A polymer object includes (a) a body portion having a surface portion thereon; (b) at least a first array of feature elements formed on said surface portion, each of said feature elements comprising: (i) a support structure connected to said surface portion and extending upward therefrom; and (ii) a top segment connected to said support structure, said top structure and said support structure together defining an internal cavity formed therein; (c) said polymer object produced as a single piece object by an additive manufacturing process.

There are a variety of manufactured objects where it is desirable to have different functional characteristics on the surface of the part rather than in the body of the object. For example, a power tool handle may require a substantially rigid body, yet a gripping surface that provides cushioning and/or vibration isolation to the operator.
Such characteristics are traditionally imparted by adhesively attaching two different materials to one another (see, e.g., U.S. Pat. No. 6,974,626) or overmolding a soft material onto another, harder, substrate material (see, e.g., U.S. Pat. No. 7,808,816). Disadvantages of overmolding, however, are that it is a complex process that requires expensive tooling, the expensive tooling makes it difficult to customize, and the resulting products may encounter adhesion problems during extended field use.
Additive manufacturing with different grades of materials offers some promise for these types of applications, but changing materials during additive manufacturing can slow the process, mechanical properties can be limited by the materials available, and again adhesion issues between different materials may be encountered during extended field use.
Accordingly, there is a need for new ways to manufacture three-dimensional objects as a single, unitary, piece of material, which objects have surface regions with functional characteristics that differ from other portions of the object.

Surface feature arrays for additively manufactured products


A self cleaning filtration device wherein an activation piston, laterally supported within an activation cylinder is immersed in filtrate within the confines of an immersion chamber. The immersion chamber receives filtrate from a disk filtration stack via orifices and sparger support tubes (the “Tubes”). Gas pressure (i) drives the piston, the Tubes, and the disk compression block upward and (ii) forces the immersion chamber fluid through the Tubes to separate the disks. The Tubes contain gas entrainment orifices on the side of the piston that are configured to facilitate entrainment of gas into the fluid. The entrained fluid impacts the opened disks with a high energy dispersed scouring action, to flush the disks clean.

1. Field of Invention
This invention provides a method and device to purvey an efficient, reliable and cost effective self cleaning disk filtration process.
2. Description of Prior Art
Modern industry and agriculture both require filtration technologies of varying capacities. Initially, innovative and higher efficiency filtration technologies evolved primarily out of the industrial market needs with agricultural filtration needs being satisfied by relatively simple and somewhat crude technologies. Concurrent with worldwide agricultural growth, and specifically as a consequence of the development of high efficiency drip tube irrigation technologies, the demand and consequential development of much more efficient, yet cost effective and reliable agricultural filtration processes burgeoned. Indeed, the previous trend of agricultural filtration technologies being primarily low cost derivatives of industrial designs has been superseded by the current industrial interest in employing modern agricultural derived technologies to industry. In many cases, adaptation of agricultural based filtration technologies into industrial applications have been positive and straight forward. Other industrial applications however, have encountered problems.
Disk filtration is one of the most promising of the filtration processes applied to the agricultural market. These agricultural based disk filtration technologies of the prior art however were fraught with problems and difficulties when applied to industrial service. The invention defined herein provides resolution to these problems and difficulties. As a point of fact, the new disk filtration technology defined herein defines superior performance for a majority of industrial filtration needs.
Disk filtration technology has been developed over many decades. There are generally two categories referenced in the art as disk filtration. One such category incorporates the parallel mounting of one or more disks comprised of a screening material encapsulating a substantially hollow plate-like structure which is generally mounted on a filtrate conduit. In such art, the filtration process occurs across the disk encapsulating screens wherein the screens may or may not include the provision of a filter aid coating such as diatomaceous earth. This subcategory of filtration technology has been commonly employed in industry for decades.
The second category of disk filtration has been developed primarily, though not exclusively, through agricultural needs. This category is the focus of this invention. This art embodies the employment of multiple ring-type disks, generally, though not always, made of a plastic material, stacked together to compose a primarily hollow cylindrical assemblage. Unfiltered water is forced, under pressure, to pass between these disks in a substantially radial direction, typically from the external to the internal side of the stack. Various types of protrusions or surface topology of the disks provide for the trammeling of particulate matter suspended in the fluid. Particle capture occurring upon the external surfaces of the cylindrical assemblage and/or upon the topologically rendered, adjacent contacting surfaces of the disks. Wherein for clarity, the trammeling surface external to the stack is substantially perpendicular to the direction of flow while that of the contacting surfaces is substantially coplanar with the direction of flow. The filtrate typically exits internal to the hollow disk stack and is ported from there to process for use.
The geometrical configuration and associated filtration mechanism of the disks as defined in the prior art are diverse. Reference is made to an early disk filter process wherein tapered disks with radial oriented internal filtrate porting was proposed for removal of a disperse sizing of particles is demonstrated in U.S. Pat. No. 1,643,299.
Other configurations practiced in the art are delineated in U.S. Pat. Nos. 2,847,126, 3,648,843, 3,827,568, 4,430,232, 4,707,259 and 4,726,900. In these practices perturbations and/or other spacing mechanisms are embodied on the disk surfaces so as to facilitate geometrical spacing between adjacent disks consistent with the required filtration size or grade. In such art the unfiltered water is constrained to pass radially between the disks of the cylindrical assemblage. Particles larger than the disk spacings therefore being trammeled upstream of the constrained fluid path. Various manifestations of this art have been further proposed in which an upstream configuration of the disks is so modified as to provide for an increased upstream surface lineage, thereby providing for an enhanced particle trammeling area. Reference is made to U.S. Pat. No. 4,410,430.
Further lessons of the art demonstrate an employment of surface grooves on one or both sides of the disks for the provision of flow channels between abutted disks. The size and geometry of said channels being the constraint on the passage of particles. Particles of sufficient size are trammeled at the entrance to the groove channels. References to these developments of the art are provided in U.S. Pat. Nos. 1,642,864 and 3,195,730.
As is compulsory with filtration processes in general, disk filtration processes require some means of filtration media surface cleansing to remove the collected solids separated from the treated fluid. Some examples of the prior art demonstrate little discussion of this issue. It can only be assumed that in these cases either disposal or disassembly and manual cleaning must be the procedure of choice. A drawback of disposal option is the expense of replacement. A disadvantage of disassembly and cleaning is the expense of labor and associated process downtime.
Prior art has evinced many examples in which the disks are cleaned through a mechanical means and/or hydraulic means. Such means being accomplished in automated, semi-automated or manually implemented processes. An example, cited in the prior art of a mechanical means for cleaning, demonstrates a procedure wherein the disks are rotated relative to one another providing a scraping mechanism and thereby facilitating removal of the collected debris. U.S. Pat. No. 1,926,557 as an example of such art. Detriments inherent in this application of the art are mechanical complexities involved in maintaining the proper relative disk orientations and the rotary mechanisms necessary to facilitate relative disk rotations. This example of the prior art also suffers from a detrimental tendency to smear or extrude rather than remove those collected solids which are soft and pliable.
Prior art has demonstrated other mechanical cleaning methods wherein brushes are employed to clean accumulated debris from the outer surface of a cylindrical filtration disk stack. Reference is made to U.S. Pat. No. 2,422,735 relating to such an invention. This example of the art suffers from mechanical complexity, high wear problems and fouling of the brushes.
Prior art has cited many examples of hydraulic cleaning processes. In these embodiments of the art, a washing liquid, generally filtrate, is directed to flush the collected solid debris from the disk stack. In the simplest form of the art, filtrate is forced to flow in a reverse manner through the filter with the aim of dislodging, separating and transporting collected solids from the filter. Solids entrained reverse flush waste fluid is then generally ported-aside for further processing or discharge.
An agricultural application in which such a reverse flow imbued cleaning process has found common use is irrigation system pre-filtration processes. In these applications, a plurality of filtration bodies containing disk filter stacks are operated in a parallel manner between a common inlet manifold and a common outlet manifold. Pressurized, unfiltered water passes from the inlet manifold through the filters, where solids are collected, and enters the slightly less pressured outlet manifold as filtrate for irrigation use.
Applications of such embodiments wherein an irrigation system and filtration process are so configured to facilitate reverse flowing pressurized filtrate from an outlet manifold for flushing of filters have been common. In these applications inlet flow to a chosen filtration body is diverted from communication with an inlet manifold to communication with a waste flush manifold. Pressure in the waste flush manifold is maintained at a level substantially lower than that of the outlet manifold. As a consequence of this pressure differential, filtrate from the outlet manifold flows in a reverse manner through the chosen filter body into the waste flush manifold. Solids collected in the chosen filter body are dislodged and conveyed, entrained within the reverse flowing stream, into the waste flush manifold for eventual discharge. Subsequent to cleaning, the filter is brought back into the filtration mode by restoration of communication to the inlet manifold and isolation from the waste flush manifold. The filtration system cleaning process then continues with sequential repetition of similar reverse flowing filtrate flushing on the remaining filter bodies in the system.
This embodiment of the art has historically found abundant applications, though it suffers substantially from inherent inadequacies in cleaning efficiency of the disk filtration surfaces. These inadequacies result from localized channeling of the flushing filtrate through isolated areas of the disk stacks as well as insufficient reverse flowing filtrate energy and associated cleaning activity to adequately dislodge solids adhering to the filtration surfaces. Consequently, such embodiments have proven to be labor intensive, requiring excessive maintenance for periodic manual cleaning of the filtration disk stacks. Mechanical failures and associated unreliability concerns are particularly prevalent and troublesome when the cleaning cycle frequency is high, as is a consequence of incomplete cleaning of the disks.
In response to the inadequacies of the simple reverse flowing filtrate flushing process, further developments of the art have been cited. To reduce channeling effects and to mechanically assist in dislodging solids adhered to disk filtration surfaces, several embodiments of the art have been cited wherein a filter disk cylindrical assemblage is decompressed and axially opened. In these embodiments an axial compressive force, which normally holds the disks tightly together, as a cylindrical stack during the filtration process, is removed in such a fashion that the filtration disk stack is substantially opened and the filtration disks rendered free floating in the axial direction. Reverse flowing filtrate is then directed through the open disk stack to flush collected solids debris from the opened and now accessible filtration surfaces. Upon completion of flushing, the disks are brought back together in compression and the filtration process resumed. Reference is made to U.S. Pat. Nos. 4,156,651, 4,402,829, 4,592,839 and 4,714,552 for examples cited of this art. These developments, though somewhat successful in improving the cleaning efficiency of the disks, still suffered from inadequate filtrate flushing energy and cleaning action upon the filtration surfaces of the disks.
Cleaning action in these examples of the prior art are burdened, especially within industrial applications, by an adherence of adjacent disks. As a result of collecting sticky or tacky solids between the disks, the disk elements will not separate when the compression force is removed for flushing. Accordingly, the filtration surfaces of these fused disks cannot be flushed. Frequent maintenance for manual cleaning is a necessity for many such industrial applications employing this prior art. As a result, such embodiments have proven to be labor intensive with an excessive amount of maintenance required for periodic manual cleaning of the filtration disk stacks. Mechanical failures and associated reliability concerns are particularly troublesome when the cleaning cycle frequency is high, as is a consequence of incomplete cleaning of the disks.
These embodiments of the prior art also suffer from failure of seals associated with disk stack compression and release mechanisms. These mechanisms require moving and sealing surfaces wherein sealing is necessary to provide isolation between the filtrate internal to the disk stack and the raw, dirty water external to the disk stack. As a consequence of a pressure differential between the internal filtrate side and external dirty water side of the filtration disk stack, dirt, grit and other detritus laden water tends to seep across the sealing surfaces. Inherent to this seepage is a deposition of dirt, grit and other detritus against the high pressure, dirty water side of the sealing surface. As a consequence of the location and abrasive nature of this deposit; abrasion, scoring and eventual sealing failure occurs. Leakage results and filtrate quality is compromised. Accordingly, these embodiments of the prior art have proven to be both unreliable and maintenance intensive.
In response to unacceptable performance and excess maintenance requirements, further developments of the art have been advanced. Developments have been cited in which a directed flushing spray, of higher velocity than available in the earlier cited examples of the prior art, is directed over a relatively small area of filtration disk surfaces. As a consequence of the limited filtration disk area contacted by the directed spray, the spray and/or the cylindrical disk stack are mechanically maneuvered, relative to each other, so as to facilitate exposure and cleaning of the entire disk filtration stack surface by the directed spray. In several of these embodiments the directed spray is generated by a drafting or suction type of action across the filtration surfaces. To facilitate this action, filter environs, comprising an internal volume of a filter housing and an associated enclosed disk stack, are maintained at a pressure elevated above that of an external waste flush fluid manifold. A hollow, open ended or slotted conduit tube, which is in hydraulic communication with the waste flush manifold, is perpendicularly juxtaposed against a relatively small upstream area of the filter disk stack. In response to a pressure differential between the fluids constrained within the filter environs and the conduit tube, a converging spray is drafted past and through a relatively small area of the disk stack and into the open end or slot of the conduit. This induced flow dislodges, cleans and conveys collected solid debris from the disk filtration surfaces to the waste flush manifold for further processing or discharge. As a consequence of the limited area of the filtration surfaces contacted by the converging fluid, the open end or slot of the conduit tube and/or the cylindrical disk stack are mechanically maneuvered, relative to each other, so as to facilitate cleaning of the entire filtration surface. Such embodiments have been cited to also include mechanisms for decompression of the disk stack. This action, as was previously recited, promotes access to the disk filtration surfaces to ameliorate the cleaning process. Examples delineating these lessons of the art are referenced as U.S. Pat. Nos. 4,042,504, 4,045,345, 4,271,018, 4,295,963, 4,906,373 and 4,923,601.
A disadvantage associated with these examples of the art is an excess volume of waste flush fluid generated. In these examples the drafting action generates a convergence of flow from the filter environs. A substantial portion of the drafted fluid does not adequately contact the filtration surfaces to provide effective cleaning. Consequently, there is an excess volume of waste fluid generated. Flushing energy and cleaning action are also limited as a result of relatively small pressure differentials inciting the fluid to draft across the disk surfaces. Further, as previously discussed with other examples of the prior art wherein disk decompression occurs prior to flushing, these embodiments also suffer from seal failure and adhesion of adjacent disks.
Other examples of the prior art have been cited in which a flushing flow is delivered in the form of one or more pressured flushing sprays directed over relatively small areas of a filtration disk stack. Cited examples have professed sprays in several formats, one being wherein a high pressure flushing fluid is delivered from external of a filter to one or more spray nozzles incorporated onto an axially movable and rotatable conduit. In such embodiments, filtration flow is typically in a radial direction, external to internal through a hollow cylindrical stack of filtration disks. The spray nozzles are upon the conduit, which extends within the hollow cylinder of the filtration disk stack. The spray nozzles are so oriented as to facilitate a flushing spray, directed radially outwards, through the disk stack. Axial and rotational relative motion of the sprays across the disk stack occurs via axial and rotary motion of a section of the rigid conduit external to the filter. This motion provides spray contacting of the entire interior surfaces of the disk stack. Such embodiments have been cited to also include mechanisms for decompression of the disk stack. This action, as was previously recited, promotes access to the disk filtration surfaces to ameliorate the cleaning process. Examples of such embodiments can be referenced as U.S. Pat. Nos. 4,308,142, 4,655,910, 4,655,911, 4,906,357, 5,393,423 and 6,318,563.
Modifications manifest within these cited examples improve filtration performance on some industrial applications, though problems with disk adherence and plugging still exist within many industrial applications. These embodiments of the prior art also suffer from failure of seals associated with the movable conduit and seals associated with disk stack compression and release mechanisms. Conduit seals are necessary to provide isolation between pressured raw and dirty water internal to the filter and external environs of the filter.
As a consequence of a pressure differential between the filter external and internal environs, dirt, grit and other detritus laden water tends to seep across the sealing surfaces. Inherent to this seepage is a deposition of dirt, grit and other detritus against the high pressure, dirty water side of the sealing surfaces. As a consequence of the location and abrasive nature of this deposit; scoring of the seal surfaces followed by leakage and sealing failure eventually occur. Similarly, these embodiments of the prior art also suffer from failure of seals associated with disk stack compression and release mechanisms. These mechanisms require moving and sealing surfaces wherein sealing is necessary to provide isolation between the filtrate internal to the disk stack and the raw, dirty water external to the disk stack. As a consequence of a pressure differential between the internal filtrate side and external dirty water side of the filtration disk stack, dirt, grit and other detritus laden water tends to seep across these sealing surfaces. Inherent to this seepage is a deposition of dirt, grit and other detritus against the high pressure, dirty water side of the sealing surface. As a consequence of the location and abrasive nature of this deposit, abrasion, scoring and eventual sealing failure occurs. As a result, leakage occurs and filtrate quality is compromised. Because of these multiple sealing problems, these embodiments of the prior art have proven to be both unreliable as well as maintenance intensive. As a further disadvantage, the flushing sprays in these embodiments do not provide focusing means to maximize hydraulic energy and impact of the sprays as is necessary to adequately separate adhering disks and scour the filtration disk surfaces. These flushing sprays of the prior art do not provide and maintain sufficient energy and disk cleaning activity necessary for many industrial applications.
Another embodiment of the prior art citing disk flushing by directed sprays, employs the delivery of flushing fluid from external of a filter to a full circle spraying assembly via a conduit tube movably situated through a filter housing and internally extending axially into a filtration disk stack. Reference U.S. Pat. No. 4,156,651. In this embodiment, disk flushing is purveyed by a relatively thin circular, planar type spray, directed and impacting radially outward upon the disk surfaces. To facilitate full coverage of the disk stack during a flushing operation, the circular spraying assembly is extracted axially through the disk stack, as motivated by movement of the conduit, concurrent with full circle, radial spraying of flushing fluid through the disks. Such embodiments have been cited to also include mechanisms for decompression of the disk stack. This action, as was previously recited, promotes open access to the disk filtration surfaces to ameliorate the cleaning process. Developments manifest within this cited example improve filtration performance on some industrial applications, although problems with disk adherence and plugging still exist within many other industrial applications. This embodiment of the prior art also suffers from failure of seals associated with the movable conduit and seals associated with disk stack compression and release mechanisms. Conduit seals are necessary to provide isolation between pressured, dirty water internal to the filter and external environs of the filter. As a consequence of a pressure differential between the internal and external environs of the filter, dirt, grit and other detritus laden water tends to seep across these seals. Inherent to this seepage is a deposition of dirt, grit and other detritus against the high pressure, dirty water side of the seal. As a consequence of the location and abrasive nature of this deposit; scoring of the seal surfaces followed by leakage and sealing failure eventually occur. Similarly, this embodiment of the prior art also suffers from failure of seals associated with disk stack compression and release mechanisms. These mechanisms require moving and sealing surfaces wherein sealing is necessary to provide isolation between the filtrate internal to the disk stack and the raw, dirty water external to the disk stack. As a consequence of a pressure differential between the internal filtrate side and external dirty water side of the filtration disk stack, dirt, grit and other detritus laden water tends to seep across these sealing surfaces. Inherent to this seepage is a deposition of dirt, grit and other detritus against the high pressure, dirty water side of the sealing surface. As a consequence of the location and abrasive nature of this deposit, abrasion, scoring and eventual sealing failure occurs. As a result, leakage occurs and filtrate quality is compromised. Because of these multiple sealing problems, these embodiments of the prior art have proven to be both unreliable as well as maintenance intensive. As a further disadvantage, the flushing sprays in these embodiments do not provide focusing means to maximize hydraulic energy and impact of the sprays as is necessary to adequately separate adhering disks and scour the filtration disk surfaces. The flushing sprays of this prior art do not provide and maintain sufficient energy and disk cleaning activity necessary for many industrial applications.
Further examples cited of the prior art, reference U.S. Pat. Nos. 4,655,910 and 4,655,911, exhibits the flushing efficiency of the directed spray approach, but eliminates much of the mechanical complexity associated with relative movement between the filtration disks and the directed sprays. In these embodiments, within a filter body, a filtration disk stack circumscribes a centralized, rigid element which is secured to the filter body on one end and freestanding on the other. This element is oriented in the axial direction of the disk stack and provides the rigid, lateral support necessary to maintain the cylindrical configuration of the filtration disk stack. An axially movable cap is supported on seal bearing surfaces at the free standing end of this element. When this cap is moved toward the secured end of the rigid element it compresses the filtration disk stack to facilitate filtration. When moved axially away from this position, the compression on the filtration disk stack is relieved and the disk stack is axially opened to facilitate flushing. Located on extended walls of this element are a series of spray nozzles so oriented as to equally impart a tangentially oriented spray upon the disks circumscribing the element. The secured end of the rigid element supports a critical flow check mechanism. During filtration this flow check mechanism directs filtrate flow from internal of the compressed disk stack to a filtrate discharge port exiting the filter. Upon reversing flow of filtrate back through this discharge port into the filter, the critical flow check mechanism directs the reverse flowing filtrate via hollow sections of the rigid element to lift the end cap, thereby decompressing the disk stack. Concurrently, reverse flowing filtrate is also conveyed through hollow sections of the rigid element to the spray nozzles for spray flushing the encircling disks. The similar tangential orientations of the sprays initiate a vigorous rotational spin of the disks about the rigid element. The multiple, axial placement of the spray nozzles and the rotational spin of the disks are intended to convey full flushing spray coverage of the disk stack.
The flow check mechanisms cited in these examples of the prior art have proven to be disadvantageous for several reasons. These flow check mechanisms engender a high pressure drop thereby purveying a substantial hindrance to flow through the filters. Accordingly additional filters and/or high pressure pumps must be employed to facilitate adequate flow. This is expensive and adds further operational complexity. Further, these flow check mechanisms have proven to be unreliable, sensitive to water treatment chemicals and maintenance intensive.
The performance of these embodiments of the prior art show some improvement over the previous lessons of the art, although in many industrial applications they still suffer from inadequate flushing energy and cleaning action upon the solids laden disk filtration surfaces. One specific inadequacy relates to voids of flushing spray upon the disks resulting from axial spacing gaps of the spray nozzles on the rigid element. As a result, the disk stack separates into a series of mini stacks of adhering disks. These disks adhere together because, as a result of spacing gaps between the spray nozzles on the rigid element, no spray impact occurs. These mini stacks are contacted by flush sprays only on the upper surface of the top disk of the mini stack and the lower surface of the bottom disk of the mini stack. Indeed, the presence of a top spray and a bottom spray only, with a void of spray in the middle of the mini stack, actually holds the affected disks together, hindering their separation for cleaning. Flushing efficiency of the sprays is further compromised by the similar orientation of the sprays. Each spray purveys a similar rotational impetus to the disk stack because of the similar tangential orientation of the sprays. Such rotation is intended to facilitate maximum spray coverage of the disk stacks. The disks are motivated by the sprays to rotate in the direction of the sprays. However, because of the common orientation of the sprays, these embodiments suffer from the generation of excessively high rotational speeds of the disks. As the rotational speed of the disks approach the velocity of the spray, the impact energy of the spray upon the disks approaches zero. Cleaning energy and efficiency drop dramatically and the disks do not flush clean.
These embodiments of the prior art employ the movable end cap to facilitate compression and decompression of the disks. The end cap slides down and up, respectively, on sliding sealing surfaces of the end cap and the rigid element. In these examples of the prior art, these sliding surfaces incorporate one or more seals to isolate the filtrate internal to the disk stack from the raw feed-water external to the disk stack. As a consequence of a pressure differential between the internal filtrate side and external dirty water side of the filtration disk stack, dirt, grit and other detritus laden water tends to seep across the sealing surfaces. Inherent to this seepage is a deposition of dirt, grit and other detritus against the high pressure, dirty water side of the sealing surface. As a consequence of the location and abrasive nature of this deposition; abrasion, scoring and eventual sealing failure occurs and the filtrate quality is compromised. Accordingly, these embodiments of the prior art have proven to be unreliable and maintenance intensive.
A further disadvantage of these embodiments of the prior art relate to the configuration of the sprays. The spray nozzles incorporated therein generate a diverging, expanding spray which rapidly drops in energy as it exits the nozzles and contacts the disks. Accordingly the lower spray energies result in an inability for the spray to separate adhering disks as well as purveying an inferior cleansing action to those disks which have separated.
A further disadvantage of these embodiments of the prior art is the requirement of at least two, three-way valves or four, two way valves, externally mounted to a raw water inlet and filtrate outlet of the filters. These valves are necessary to facilitate filtration operations and reverse flushing operations. These valves are expensive, high maintenance mechanisms which are particularly prone to leakage and failure.
In a prior patent granted to this inventor, reference U.S. Pat. No. 6,752,920, there is presented a filter embodiment comprised of three body chambers. One chamber contains a filter disk stack with the internal region of the disk stack ported into a filtrate plenum chamber. The filtrate plenum chamber is ported for filtrate discharge from the filter. A third flush fluid receiving plenum chamber is provided to receive an externally supplied flushing fluid for cleaning the filter disks. The filter disk stack circumscribes several rigid hollow shafts. These shafts are oriented in the axial direction of the filter disk stack and provide lateral support necessary to maintain a cylindrical configuration of the filtration disk stack. Oriented on these shafts, adjacent to the disk stack, is a plurality of nozzle holes wherein a slight majority of the nozzles are configured tangentially in one direction while the remaining, slight minority of the nozzles, are oriented tangentially in an opposing direction. These nozzles provide hydraulic communication between the hollow interior and the exterior of the shafts. The lower ends of the shafts pass, in a rigid, sealed fashion, through the filtrate plenum cavity and terminate within, and in hydraulic communication with, the flush fluid receiving plenum of the filter. The hollow interior sections of these shafts provide a conduit for flow of the cleaning medium from the flush fluid receiving plenum to the nozzles. The ends of the hollow shafts opposite the flush fluid receiving plenum support an axially movable, combined inlet valve seat and disk compression assembly. This assembly moves axially toward the disk stack during filtration to facilitate compression of the disks. During flushing operations, this assembly moves in an axial direction away from the disk stack, thereby releasing the disks for flushing, while concurrently seating in and closing an inlet port to the filter. This assembly further supports a shaft which is directed axially opposite to the inlet valve seat and disk compression assembly and extends into the filtrate plenum. The free end of this shaft supports a block valve located within the plenum chamber. While in the filtration mode, the combined inlet valve seat and disk compression assembly is compressed against the disks and the shaft moves the block valve into an open position facilitating communication between the interior filtrate volume of the disk stack and the filtrate plenum. During flushing operations, the flushing fluid is introduced, under pressure, into the flush fluid receiving chamber. The pressured fluid moves through the hollow shafts supporting the disks and motivates the inlet valve seat and disk compression assembly away from the disks and into a sealing position on the inlet port. Concurrently, the flushing fluid expels from the nozzles and impacts, in a cleansing fashion, across the filtration surfaces of the disks. The disks rotate at a low speed in the direction imposed by the slight majority of the nozzles. The spray from these nozzles impacts the disks in a head on fashion thereby providing an optimum spray cleaning performance.
This embodiment of the art provides substantially improved cleaning performance as a result of multi-directional nozzle orientations, reduced pressure drop by not requiring any check valves and the ability to employ an exterior, higher pressure, source of cleaning fluid. Further, the disadvantages associated with the required inlet and outlet valves of the prior art are eliminated. Though the performance improvements heralded by this prior art of this inventor were extraordinary, several disadvantages still remained to be addressed. One of these problems was the adherence of adjacent disks due to sticky collected solids and the consequential inability to flush clean the closed disk surfaces. These problems relate to both the fore-mentioned void spaces on the disk stack resulting from rigidly mounted spray nozzles and from the reduced flushing energy associated with diverging sprays exiting the nozzles. Another disadvantage of this prior embodiment of the art by the inventor, is the unreliability and maintenance required of moving seals on the disk compression end cap assembly in the presence of abrasive solids in the raw feed-water to the filter. Another disadvantage is the requirement of a flush valve to control the inlet of flushing fluids. This valve must be of sufficient size to accommodate the high flow rates required for efficient flushing and cleaning of the disks. As a consequence, the size and cost of this valve is substantial. Further, if chemicals are employed in the flushing fluid, the materials of construction of this valve must be resistant to these normally harsh chemicals. Such exotic materials add substantially to the cost of the valve. The disadvantages of the flush valve in this prior art of the inventor are numerous.
Another disadvantage of this latest example of the prior art corresponds to sliding seals which are required in the movable valve seat and disk compression assembly. These sliding seals are necessary to separate the filtrate internal to the filtration disk stack from the dirty, pre-filtered water external to the filtration disk stack. As a consequence of a pressure differential between the internal filtrate side and external dirty water side of the filtration disk stack, dirt, grit and other detritus laden water tends to seep across the sealing surfaces. Inherent to this seepage is a deposition of dirt, grit and other detritus against the high pressure, dirty water side of the sealing surface. The location and abrasive nature of this deposit results in an eventual failure of the seals, thereby compromising the filtrate quality.
The disk flushing procedures of the prior art have generally employed filtrate for flushing operation. For those applications in which the available filtrate is of insufficient pressure, external pressurized filtrate or other flushing fluid sources have been employed. Applications of the prior art have employed municipal water, pump pressurized filtrate and compressed air sources in an air over water approach to develop pressure for flushing. High externally supplied pressures generally improve flushing performance however, frictional pressure losses internal to the filters, throttling pressure losses through valves, throttling pressure losses through flush nozzles and energy loss through diverging spray patterns all dramatically reduce the flushing energy exerted upon the solids laden disk filtration surfaces. As a consequence, in many industrial applications, the employment of these alternative high pressure flushing processes is still insufficient to provide satisfactory cleaning of the filtration surfaces. Consequently, to facilitate effective filtration disk cleaning in such circumstances, the filters of the prior art must be dismantled and the disks removed and chemically washed. This is a labor intensive, time consuming, costly and inefficient process.
A further disadvantage in the prior art relates to the inability to readily employ chemicals beneficial for cleaning of the filtration disks. Often in industrial applications, solids adhere to the disks with such tenacity that chemicals must be employed to adequately clean the filtration disks. In order to facilitate such cleaning, the filters of the prior art must be dismantled and the disks removed and chemically washed. This is a labor intensive, time consuming, costly and inefficient process.
Industrial applications often result in a deposition of solids upon the filtration disk surfaces which require elevated temperatures for effective cleaning. A disadvantage of the prior art is that there are no ready provisions to facilitate flushing of the filtration disks at elevated temperatures. Those industrial applications in which elevated temperatures are necessary for adequate filtration disk cleaning either require the employ of an isolated, heated, high pressure cleaning fluid source or dismantling of the filters, removal of the filtration disks and external washing of the filtration disks at an elevated temperature. This is a labor intensive, time consuming, costly and inefficient process.
In a similar fashion, there are many industrial applications wherein the only method for successful cleaning of the filtration disks requires cleaning with chemicals at elevated temperatures. The prior art teaches no ready options for this procedure other than flush fluids supplied by external, heated tankage or dismantling of the filter, removal and elevated temperature chemical cleaning of the filtration disks. This is a labor intensive, time consuming and inefficient process.
Another disadvantage of the prior art is biotic plugging and fouling of the filtration disks. This problem arises from biological growth developing on the filtration disk surfaces. This common problem presents a substantial impediment to cleaning of the filtration disks. Further, the problem continues even after apparently successful flushing as a consequence of the growth of residual biotic cultures remaining on the disks. There are no methods taught by the prior art to resolve these problem other than dismantling of the filter, removal, cleaning and sterilization of the disks and any other effected internal structures by chemical, thermal or combined means. This is a labor intensive, time consuming, costly and inefficient process.

Filtrate immersed activation assembly for disk filters


A subsea storage structure for treatment and storing drill cuttings from drilling operations in the sea bottom includes a generally closed container or tank suitable to be positioned on the sea bottom near the drilling site, which tank is provided with an upper inlet for supply of drill cuttings, and an output to ambient water for water which is displaced during the supply of drill cuttings. The tank contains arrangements for cleansing of the drill cuttings and storage of accumulated oil, fluids and other constituents separated from the drill cuttings, and structure for extraction of the accumulated oil, fluids and other constitutents lighter than water.

The present invention relates in general to subsea storage and cleansing of drill cuttings from holes drilled in the sea bed, especially in connection with hydrocarbon exploration. More particularly the invention relates to a storage structure designed to be positioned on the sea bottom for storage and cleansing of drill cuttings continuously delivered from nearby drilling operations.
Furthermore, the invention relates to a method for cleansing and separation of drill cuttings from oils, fluids and other contaminating constituents.
In connection with drilling operations in the sea bed drilling fluids and drilling slurries are pumped down during the drilling for different purposes, such as cooling, lubrication of the drill bits, prevention of corrosion, and also in order to create a pressure barrier in order to sustain those substantial pressures which may occur in the drill well when reaching ground formations with high pressures. Two main types of drilling fluids and drilling slurries are used, namely water-based and oil-based. Oil-based drilling fluids are primarily used to provide a lubrication of the drill string in the well and also to prevent corrosion of the drilling equipment. Oil-based drilling fluids are further used for drilling at high temperatures, in order to improve well stability and reduce scaling, and in order to control possible risks of water penetration. While drilling fluids and slurries are primarily used in order to create a pressure barrier in connection with high pressures in the well, they also serve as a supporting vehicle for the well cuttings which are generated during the drilling. Drill cuttings, contaminating oils, drilling fluids and the like are continuously transported up to the surface, i.e. to the drilling platform or drilling vessel where the drill cuttings and the drilling fluids to a certain degree are filtered for recovery of the drilling slurries. The drill cuttings are thereafter usually dumped in the sea and come to rest at the sea bottom.
The drilling cuttings normally contain both oil and various chemicals which usually are located as a film encompassing the drill cutting particles. If the cuttings are disposed of by dumping into the sea, oil and chemicals detach from the cutting particles and then normally will float up and form oily films on the sea surface, thereby contaminating the sea water.
One is here speaking of considerable quantities and volumes. Asan example, it can be mentioned that in the North Sea during the first six months of 1989 it was planned to drill altogether 125 oil and gas wells, and the drill cuttings from a single well may constitute approximately 500 metric tons. Knowing that oil contaminated drill cuttings may contain up to 50 volume % oil-based fluid one will understand that the risk of substantial environmental contaminations is rather great.
In this technical field great efforts have therefore been made to provide steadily improved methods for cleaning of the drill cuttings. For separation and cleansing of the drill cuttings are utilized both burning and/or chemical methods. It is obvious that such methods will be expensive, and the results have hitherto not been satisfactory.
An alternative to separation and cleansing is to accumulate the drill cuttings for transporting the same ashore with barges or the like, possibly for further cleansing and storage ashore. Such procedures obviously are rather expensive and new problems will arise in connection with storage ashore.

Method and means for cleansing and storing drill cuttings from drilling operations in the sea bottom


A resonator device for testing a material quantity in the tobacco-processing industry for existence of at least one foreign substance and/or for detecting at least one of weight, density and humidity level of the material includes a resonator housing having a through opening for the material to pass through and a testing region located inside the resonator housing to which the material can be moved at least in part. The device has at least one element that increases energy density of electromagnetic waves for increasing the energy density in at least a portion of the testing region.

Priority is claimed herein with respect to German Patent Application Serial Nos. 101 12 499.6 filed on Mar. 15, 2001 and 101 57 266.2 filed on Nov. 22, 2001, the subject matter of which, along with the subject matter of each and every U.S. and foreign patent document mentioned herein, is incorporated herein by reference.
The invention relates to a resonator device, in particular a microwave resonator device, for testing a material quantity and especially a material flow in the tobacco-processing industry for the existence of at least one foreign substance and/or for detecting the weight, density and/or humidity level of the material or material flow. The resonator device is provided with at least one resonator housing and at least one opening in each resonator housing for the material or material flow to pass through.
The invention furthermore relates to a corresponding measuring device, especially a microwave measuring device, as well as a measuring system, in particular a microwave measuring system, for testing a material quantity and especially a material flow in the tobacco-processing industry for the existence of at least one foreign substance and/or for detecting the weight, density and/or humidity level of the material. Such a measuring device comprises at least one resonator housing, inside of which an electromagnetic field can be generated and which has at least one through opening for the material.
Finally, the invention relates to a method for testing a material for the existence of at least one foreign substance and/or for detecting the weight, density and/or humidity level of the material.
A corresponding resonator device or resonator housing for microwaves is known from German Patent No. 198 54 550 A1 commonly owned by the present assignee. This document discloses a resonator housing for the tobacco-processing industry, through which a rope of tobacco is moved and is subjected to microwaves for the purpose of detecting the weight and/or humidity level of the rope material. The purpose of this resonator housing is to improve the measuring accuracy and, if necessary, the measuring sensitivity when detecting the weight and/or humidity level of filler materials for ropes in the tobacco-processing industry. According to German Patent No. 198 54 550 A1, this is achieved by producing the housing at least in part from a material with a low expansion coefficient, so that with a corresponding fluctuation in the temperature, the housing essentially retains the same shape. It also improves the measuring accuracy if the resonator housing temperature is controlled to be at a constant value. Finally, it is advantageous according to the aforementioned reference if the interior housing walls are at least partially coated with a corrosion-resistant metal or consist of such a metal. The measuring accuracy for detecting the weight and/or humidity level for the aforementioned materials can be improved considerably in this way.
German Patent No. 101 00 664.0 also commonly owned by the present assignee, furthermore discloses a method for testing a production material or a material quantity primarily containing a production material, wherein the material is tested for the existence of a foreign substance. A microwave field is generated for this, the material is moved into the effective range of the microwave field and its influence on the microwave field is analyzed, wherein the actual values of a first and a second characteristic variable of the microwave field are measured simultaneously. A reliable value range is specified for these actual values and these are checked to determine whether the actual values are in the reliable range. A signal is generated if the actual values are outside of the reliable value range. For the purpose of this invention, the variable for a microwave field includes real variables of the generated microwave field, such as amplitude and phase, as well as variables of the components for guiding a microwave field, e.g. the resonance frequency and the band width of a resonator in which the microwave field propagates.
With the known measuring method, the goods to be measured are moved through the field of a resonator, wherein the dielectric properties of the goods to be measured change the field. By measuring the change in the resonance properties or the field, it is possible to determine the weight, density and humidity level as well as to detect foreign substances. However, it is difficult to detect very small foreign substances or to achieve a relatively exact local resolution. In particular the position of the foreign substance relative to the field orientation determines the measuring accuracy.
It is an object of the present invention to provide a resonator device, a measuring device and a measuring system, which increase the sensitivity of a method for determining whether a material flow contains a foreign substance and/or for detecting the weight, density and/or humidity level of the material flow or the material quantity.
Furthermore, it is an object of the present invention to increase the sensitivity of such a method and, in addition, provide means and a method for improving the accuracy and the local resolution of respective measurements.
The above and other objects are solved with a resonator device, in particular a microwave resonator for testing a material, in particular a material flow, in the tobacco-processing industry for the existence of at least one foreign substance and/or for detecting the weight, density and/or humidity level of the material or the material flow. The resonator device comprises a housing provided with an opening for the material quantity or the material flow to pass through, wherein the material can be transferred at least in part to a testing area, located in particular inside the resonator. At least one element that increases the energy density of electromagnetic waves is provided, wherein the energy density can be increased at least in a portion of the testing area.
As a result of this measure, a kind of bundling of the electromagnetic waves is possible in the testing area, which results in an increased flow of the respective waves, in particular microwaves, through the material to be checked or the region of the material flow to be checked. As a result, the sensitivity when measuring the weight, density and/or humidity level of the material flow and/or when testing for the existence of a foreign substance is increased, without the necessity of coupling additional energy into the resonator device. For the purpose of this invention, increasing or raising the energy density of electromagnetic waves in particular also means that these waves are bundled, focused, narrowed down or compacted. The electromagnetic waves preferably are microwaves. A material is advantageously tested with the resonator device according to the invention. The material advantageously is a material flow. For the purpose of this invention, the term testing region also encompasses the term measuring region.
The element preferably comprises a line resonator with at least one end face functioning as electrode. By using a line resonator, the waves coupled into the resonator can be bundled easily and effectively, wherein the waves or the respective field in particular exit the end face in the form of a beam.
It is advantageous if a coupling-in antenna and a coupling-out antenna are provided, which are arranged symmetrically inside the resonator. The antennas are furthermore arranged near a spot on the line resonator, where the field component that induces the coupling has a high amplitude, preferably a maximum.
A particularly good coupling of the waves coupled in and out of the element occurs if the element is preferably arranged inside a resonator cavity, at a distance to the walls delimiting the cavity.
A particularly effective method for testing the material flow is possible if the at least one end face is arranged near the material flow or the material quantity or the testing region. The size of the end face preferably is smaller than the region of the material flow, located inside a testing region in the resonator, wherein a cross-sectional surface that is essentially parallel to the end face is taken into consideration. The material flow, which in this case is a tobacco flow in the tobacco-processing industry that is advantageously wrapped with a wrapping material such as paper, refers to a cigarette rope having a circular diameter of approximately 6 to 10 mm. The size of the end face, which may be rectangular, is preferably smaller than {fraction (1/10)} of the area for the material flow to be projected against one wall of the resonator device. This refers, for example, to an area ratio as shown in FIG. 2, wherein the decisive area is the cross-sectional surface of the cigarette rope inside the cavity 7, which is shown in FIG. 2.
The line resonator preferably is a metal strip or a thin metal cube with an end face in the direction of the testing region. If at least one inside wall of the resonator housing preferably serves as an electrode, particularly as a backplate electrode to the end face, the electromagnetic wave field can be generated between the end face of the metal strip and the inside wall, so that a defined, narrowly limited measuring range is provided.
Two end faces are advantageously provided, which are directed toward the testing region. A particularly preferred embodiment of the resonator device has two end faces, wherein these are arranged opposite each other to allow the material flow to move through the space between the end faces. Such an embodiment of the resonator device permits a particularly even bundling of the waves, wherein an extremely high energy density is possible. The line resonator preferably is an open ring. In addition, the two end faces preferably are essentially parallel to each other, which further increases the homogeneity of the wave field.
Extremely reliable and exact measurements are possible if the one element consists at least in part of a material with low expansion coefficient, especially with respect to temperature. A long service life is ensured for the resonator device if the at least one element furthermore is coated with a corrosion-resistant material and in particular a metal and/or consists in part of such a material.
The invention further provides for a measuring device, in particular a microwave measuring device, for testing a material, especially a material flow in the tobacco-processing industry, for the existence of at least one foreign substance and/or for detecting the weight, density and/or humidity level of the material. The invention comprises at least one resonator housing, which is provided with at least one opening for the material to flow through and inside of which an electromagnetic field can be generated. The invention is modified in that the measuring device comprises at least two resonator housings, which respectively define one measuring range, wherein each electromagnetic field respectively comprises an electric field and the fields in the respective measuring regions are oriented in different spatial directions relative to each other. The electromagnetic field in this case is preferably a microwave field, comprising a stationary microwave field in the resonator housing. According to the invention, the different directions, relative to each other, of the electrical fields permit a more exact determination of foreign substances since foreign substances not detected with the one resonator housing can be detected with a high probability with the other resonator housing. In particular this refers to foreign substances having a geometric shape that is larger in one direction than in the other direction. Having different field directions relative to each other in space means, in particular, that these fields are distinguished by different angles relative to the conveying direction.
The measuring regions preferably are positioned successively in a conveying direction of the material flow, so that a separate evaluation of the respective measurements of the material quantity in the measuring regions can take place and so that the individual measuring regions are not influenced by the adjacent measuring region.
A particularly preferred embodiment of the present invention is obtained if the electrical fields are oriented essentially orthogonal to each other. For the purpose of this invention, orthogonal means perpendicular to each other.
If one electrical field is oriented essentially in the conveying direction of the material flow and one electrical field is oriented crosswise thereto, it is possible to take a measurement in the traditional manner, for example as described in German Patent No. 198 54 550 A1, as well as take a supplemental measurement crosswise to this direction.
For the purpose of this invention, field refers in particular to an electrical field. In the case of a dynamic field, the field intensity vector represents one field direction or orientation, as for a stationary electromagnetic wave.
If three resonator housings are provided, the measuring accuracy can be increased even further. For this, the third resonator housing is preferably designed so that the electrical field is positioned essentially orthogonal to the fields inside the other two resonator housings.
The measuring device according to the invention preferably comprises a resonator device that is designed or advantageously equipped according to the invention, as described in the above. A compact design for the measuring device is obtained if a single housing comprises at least two resonator housings.
According to a further aspect of the invention, there is provided a measuring system, particularly a microwave measuring system, for testing a material flow in the tobacco-processing industry for the existence of at least one foreign substance and/or for detecting the weight, density and/or humidity level of at least a section of the material flow. The measuring system is modified in that at least two measuring devices are provided for measuring the material flow in space, in different directions relative to each other. In this case, the measuring direction must be understood to be the direction of the field that is critical for the measurement, particularly the electrical field. For this, at least one measuring device is preferably designed such that a measuring in the conveying direction of the material flow is possible. German Patent No. 198 54 550 A1 shows in this connection, a corresponding measuring device that permits a measurement in the conveying direction of the material flow. One of the resonator devices according to the invention can be used, for example, as described in the above if at least one measuring device is designed to permit a measuring crosswise to the conveying direction of the material flow.
In a preferred embodiment of the invention, three measuring devices are advantageously provided, wherein the measuring devices are designed such that the material flow can be measured in three different spatial directions, relative to each other, in particular in essentially orthogonal directions. Very exact measurements and in particular measurements with a high local resolution are possible with a measuring system of this type. It is advantageous if the measuring device, which permits a measurement crosswise to the conveying direction, is one of the resonators according to the invention and described in the above.
According to yet another aspect of the invention, there is provided a method for testing a material quantity, in particular a material flow in the tobacco-processing industry, for the existence of a foreign substance and/or for detecting the weight, density and/or humidity of the material. For this, a first electromagnetic field is generated in a first resonator and a second electromagnetic field is generated in a second resonator, the material is moved through the first and the second field and a change in at least one characteristic of the electromagnetic field is measured.
The field intensity, the frequency or the phase, for example, can represent one characteristic of an electromagnetic field. In the case of a stationary wave field, the position of the antinodes or the nodes or the resonant frequency and the amplitude can furthermore represent one characteristic of an electromagnetic field, e.g. for a resonator.
The electrical fields are preferably oriented in different directions relative to each other. It must be assumed that the E field and the H field are oriented in different directions relative to each other. An even more exact analysis of the material flow based on the foreign substances or an even more exact detection of the density, humidity level and weight of the material flow is possible if a third resonator device is provided, which generates a third electromagnetic field. The material quantity is moved through this third field, which is oriented in a different direction relative to the first and second field, and the change in at least one characteristic of the third field is measured.
The electrical fields in the respective resonators are essentially positioned orthogonal to each other.
If the measured values are evaluated to generate an ejection signal, it is possible to separate out, for example, sections of the material flow from the further processing. As a result, it is possible to avoid the production of poorly filled cigarettes or cigarettes that are too dry or are composed of a foreign substance. The measured values from the resonators are preferably correlated, so that a very exact local resolution is possible. The rejection of conveyed material can be kept as low as possible with such an exact local resolution. Combining the measuring results from the different resonators thus increases the accuracy or the local resolution of the measurements.

Microwave-resonator and measuring device


A method of coding a secret, a numerical value d, subdivided into a number N of secret elements [di]n1, a composition law () applied to the elements di giving the value d. The following are calculated: (A) a first image (TN) of the secret by iterative calculation and application of the law () between the first image Ti-1 of rank i−1 and of the product according to this law of the element (di) of next rank and of a random value (Ri) of a first set, (B) a first numerical value (S1) by application of the law () to the N random values (Ri), (C) a second numerical value (S2) by application of the law to the N−1 random values (Aj) of a second set, (D) a second image T′ of the secret by application of the inverse law () to the first image (TN) and to the second numerical value (S2) so as to generate an intermediate image (Tx) and then application of the inverse law to the intermediate image (Tx) and to the second numerical value (S2). The random value (Aj) of corresponding rank is allocated (E) to the first N−1 elements (di) and the value of the second image (T′) is allocated (E) to the last element (dN). Application to secret or public key cryptography processes.

The considerable upsurge in communications by transmission of electronic messages has very quickly raised the problem of the confidentiality of the data transmitted.
Very sophisticated solutions for enciphering/deciphering these data have been proposed by means of encipherment algorithms using a single secret key, serving for encipherment/decipherment, and then a public key, with which is associated a private key, used for deciphering the data, enciphered by means of the public key.
The aforementioned solutions are satisfactory, to the extent that secret-key algorithms are hard to break, at the very least if the secret key is not compromised, and that public-key/private-key algorithms do not entail limitations as regards the dissemination of the public key and require the implementation of hardware and software means of prohibitive complexity and calculation cost with a view either to breaking the encipherment/decipherment algorithm or to retrieving the value of the private key associated with the public key.
In all events, use of a cryptographic scheme with a single secret key or a public key, with which a private key is associated, it is indispensable to prevent any compromising of the secret key or of the private key, so as to guarantee the confidentiality of the data transmitted.
Whilst satisfactory protected-access cryptographic components have been proposed, in particular integrated in the form of security processors for the cryptographic components of electronic cards, termed chip cards, exterior access by way of the input/output port to the security components of these electronic cards possibly being made extremely difficult or indeed practically impossible, the read/write manipulation of the secret or private keys by these components may allow the compromising of the aforementioned keys, in particular of the secret values or secrets entering into the definition of these values.
This compromising may occur through "hidden channel" attack (known as Side Channel attack), this type of attack possibly consisting for example in detecting the intensity variations of the electric current consumed by the security component or the card in the course of these manipulations, these being necessary.
The object of the present invention is to remedy the drawbacks of the risks of hidden channel attack, through the implementation of a method of coding a secret, subdivided into several mutually uncorrelated secret elements, it not being possible for the manipulation of the secret elements to enable the original secret to be retrieved, although each secret element might, as the case may be, be compromised.

Method of coding a secret formed by a numerical value


A radar level gauge system, for determining a filling level of a product contained in a tank, the radar level gauge system comprising: a transceiver for generating, transmitting and receiving electromagnetic signals; a propagating device electrically connected to the transceiver and arranged to propagate a transmitted electromagnetic signal towards a surface of the product contained in the tank, and to return echo signals resulting from reflections at impedance transitions encountered by the transmitted electromagnetic signal, including a surface echo signal resulting from reflection at the surface, back to the transceiver; processing circuitry connected to the transceiver and configured to determine the filling level based on the surface echo signal; and a bottom reflector arranged at a bottom of the tank. The bottom reflector comprises a plurality of phase-modifying structures, each being configured to modify a phase of the transmitted electromagnetic signal and to reflect phase-modified electromagnetic signals, wherein the plurality of phase-modifying structures are arranged in such a way that phase-modified electromagnetic signals being reflected by different phase-modifying structures interact to provide destructive interference towards the propagating device.

Radar level gauge (RLG) systems are in wide use for determining the filling level of a product contained in a tank. Radar level gauging is generally performed either by means of non-contact measurement, whereby electromagnetic signals are radiated towards the product contained in the tank, or by means of contact measurement, often referred to as guided wave radar (GWR), whereby electromagnetic signals are guided towards and into the product by a probe acting as a waveguide.
The transmitted electromagnetic signals are reflected at the surface of the product, and the reflected signals are received by a receiver or transceiver comprised in the radar level gauge system. Based on the transmitted and reflected signals, the distance to the surface of the product can be determined.
More particularly, the distance to the surface of the product is generally determined based on the time between transmission of an electromagnetic signal and reception of the reflection thereof in the interface between the atmosphere in the tank and the product contained therein. In order to determine the actual filling level of the product, the distance from a reference position to the surface is determined based on the above-mentioned time (the so-called time-of-flight) and the propagation velocity of the electromagnetic signals.
Most radar level gauge systems on the market today are either so-called pulsed radar level gauge systems that determine the distance to the surface of the product contained in the tank based on the difference in time between transmission of a pulse and reception of its reflection at the surface of the product, or systems that determine the distance to the surface based on the phase difference between a transmitted frequency-modulated signal and its reflection at the surface. The latter type of systems is generally referred to as being of the FMCW (Frequency Modulated Continuous Wave) type.
Many products, in particular liquids, are at least to some extent transparent to the electromagnetic signals in the frequency range typically used in radar level gauge systems, which may possibly cause electromagnetic signals reflected from the bottom of the tank to interfere with the electromagnetic signals reflected from the surface of the product when measuring low filling levels, i.e. the distance resolution may be insufficient to distinguish the electromagnetic signals reflected from the bottom of the tank from those reflected from the surface of the liquid.
EP 1 242 794 discloses a radar level measuring device having an absorber for microwave signals positioned at the base of the tank. Through this absorber, the reflection at the bottom of the tank can be considerably reduced, which allows measurement of low filling levels. In the radar level measurement device according to EP 1 242 794, the absorber is provided in the form of a connected plate of spikes where the tips of the spikes point in the direction of the incident microwaves. The spikes are made of a material which has a good absorption capacity for microwaves. Although the absorber according to EP 1 242 794 allows measurement of lower filling levels than was previously possible, the extension from the bottom of the tank to the top of the absorber limits the lowest filling level that can be measured to in the order of at least one wavelength of the microwave signals. As the frequency range of radar level gauging systems is typically in the order of tenths of gigahertz, the wavelength is in the order of a few centimeters.

Radar level gauge system with bottom reflector and bottom reflector


An image processing method includes the steps of generating a first image through restoration processing of an amplitude component and a phase component of an input image, generating a second image that has an equal state of the phase component to that of the first image and a different state of the amplitude component from that of the first image through restoration processing of the phase component without restoration processing of the amplitude component of the input image, obtaining difference information between the first image and the second image, setting a restoration level adjustment factor used to adjust a restoration degree in the restoration processing, and generating a restoration adjusted image by composing the difference information with the second image according to the restoration level adjustment factor.

1. Field of the Invention
The present invention relates to image processing for correcting (or reducing) a deterioration component of an image generated by image pickup, utilizing image restoration processing.
2. Description of the Related Art
An image obtained by capturing an object by an image pickup apparatus, such as a digital camera, contains a blur component as an image deterioration component, such as the spherical aberration, coma, curvature of field, and astigmatism of an image pickup optical system. This blur component occurs when a light flux emitted from one point of the object, which is expected to converge on one point on an image pickup surface when there is no aberration or diffraction, forms an image with some divergence.
The blur component, as used herein, is optically represented by a point spread function ("PSF") and is different from a blur caused by defocusing. A color shift in a color image caused by longitudinal chromatic aberration, chromatic spherical aberration, or chromatic coma of the image pickup optical system is a difference of the blurring degree among wavelengths of the light. A lateral color shift can be regarded as a position shift or phase shift due to a difference of the image pickup magnification for each wavelength of the light if the lateral color shift is caused by the lateral chromatic aberration of the image pickup apparatus.
An optical transfer function ("OTF") obtained by performing a Fourier transform for the PSF is frequency component information of the aberration and is represented by a complex number. An absolute value of the OTF or an amplitude component is referred to as a modulation transfer function ("MTF") and a phase component is referred to as a phase transfer function ("PTF"). The MTF and the PTF are frequency characteristics of an amplitude component and a phase component of the image deterioration due to the aberration. The phase component will be expressed as a phase angle by the following equation, where Re(OTF) and Im(OTF) are a real part and an imaginary part of the OTF:PTF=tan−1(Im(OTF)/Re(OTF))
Thus, the OTF of the image pickup optical system deteriorates the amplitude component and the phase component of the image, and the deteriorated image has an asymmetrical blur state of points of the object like the coma.
In addition, the lateral chromatic aberration (i.e., chromatic aberration of magnification) occurs when an imaging position shifts due to a difference of an imaging magnification for each wavelength of the light, and is obtained as RGB chromatic components, for example, in accordance with the spectral characteristic of the image pickup apparatus. The image divergence occurs not only when the image position shifts among the RGB, but also when the imaging position shifts for each wavelength of a chromatic component or when the phase shifts. Therefore, due to the phase degradation component of the aberration, asymmetry of the PSF is viewed on a primary section of each direction (azimuth direction) orthogonal to a principal ray (a ray that passes the center of the pupil of the image pickup optical system). The amplitude degradation component affects the size of the spread of the PSF for each azimuth direction.
In order to highly precisely correct through image processing the image degradation caused by the image pickup optical system, it is thus necessary to correct the phase degradation component and the amplitude degradation component of the aberration.
Edge enhancement processing is a known method of correcting the amplitude degradation component by detecting an edge portion in an image and by enhancing the edge as disclosed in Japanese Patent Laid-Open No. ("JP") 2000-156816.
A geometric correction is a known method of correcting a phase degradation component by varying an image magnification for each chromatic component of an image as disclosed in JP 06-113309.
Another known method of correcting the amplitude degradation component and the phase degradation component utilizes the OTF information of the image pickup optical system. This method is referred to as an image restoration or image recovery, and processing used to correct (or reduce) an image degradation component utilizing the OTF information will be referred to as image restoration processing hereinafter.
The image restoration processing will be outlined as follows: Assume that g(x,y) is a deteriorated image (input image), f(x,y) is a non-deteriorated, original image, and h(x,y) is the PSF as a Fourier pair of the OTF. Then, the following equations are established, where * denotes a convolution and (x,y) denotes a coordinate on an image.g(x,y)=h(x,y)*f(x,y)
The above equation is converted into a display format on a two-dimensional frequency plane by a Fourier transform, which is a format of a product for each frequency. "H" denotes a Fourier-transformed PSF or corresponds to the OTF. (u,v) denotes a coordinate on the two-dimensional frequency plane or corresponds to a frequency.G(u,v)=H(u,v)·F(u,v)
In order to obtain the original image from the deteriorated image, both sides are divided by H as follows:G(u,v)/H(u,v)=F(u,v)
When this F(u,v) is inverse-Fourier-transformed and returned to the real surface, the restored image corresponding to the original image f(x,y) can be obtained.
Where R denotes an inverse Fourier transform of H−1, the original image can also be obtained through the convolution processing to the image on the real plane as in the following equation:g(x,y)*R(x,y)=f(x,y)
This R(x,y) is referred to as an image restoration filter. For a two-dimensional image, the image restoration filter is usually a two-dimensional filter having a tap (cell) corresponding to each pixel of the image. In general, as the number of taps in the image restoration filter increases, the restoration precision improves. The image restoration filter needs to reflect at least an aberrational characteristic, and is remarkably different from a conventional edge enhancement filter (high-pass filter) having about three taps in each of the horizontal and vertical directions. Since the image restoration filter is prepared based on the OTF, the deterioration of each of the amplitude component and the phase component can be highly precisely corrected.
The real image has a noise component, and the noise component is remarkably amplified disadvantageously along with the restoration of the deteriorated image when the restoration utilizes the image restoration filter made with a perfect reciprocal of the OTF. With noises, an image worth viewing cannot generally be obtained.
This can be expressed by the following equations where N denotes a noise component:G(u,v)=H(u,v)·F(u,v)+N(u,v)G(u,v)/H(u,v)=F(u,v)+N(u,v)/H(u,v)
For example, like a Wiener filter illustrated by Equation 1, there is a known method of controlling the restoration degree (or restoration level) in accordance with a signal to noise ratio ("SNR") between an image signal and a noise signal:
                              M                                (                          u              ,              v                        )                          =                              1                          H                                            (                                  u                  ,                  v                                )                                                                                                                  H                                                        (                                          u                      ,                      v                                        )                                                                              2                                                                                                              H                                                              (                                              u                        ,                        v                                            )                                                                                        2                            +                              SNR                2                                                                        Equation                                                  1
M(u,v) denotes a frequency characteristic of the Wiener filter, and |H(u,v)| denotes an absolute value (MTF) of the OTF. For each frequency, this method further restrains the restoration gain as the MTF is smaller or the SN ratio is lower, and further enhances the restoration gain as the MTF is larger or the SN ratio is higher. In general, the MTF of the image pickup optical system is high on the low frequency side and low on the high frequency side, and thus the restoration gain of the image is restrained substantially on the high frequency side.
When the noises are impermissible to the desired image quality after the restoration processing is performed by setting the actual SNR to a parameter, an additional restraint on the noise amplification is necessary by adjusting the SNR parameter so as to reduce the restoration gain. This corresponds to the SNR value in Equation 1 set to a larger value. In addition, when there is a difference between the aberrational characteristic in the actual image pickup condition and the aberrational characteristic estimated by the image restoration filter, the restored image may contain a problem of an artifact, such as ringing. Moreover, when the restoration degree is different from the estimated one for each of the RGB chromatic components, the restored image may be colored or a false color may occur. This false color is also one of the artifacts, such as noises and ringing.
FIG. 15 illustrates false colors in a restored image. The false color occurs as illustrated by a broken line in FIG. 15. A false color "A" occurs when an edge part is further colored than a pre-restoration image caused by the manufacturing error. A false color "B" occurs when a periphery of a brightness saturation part is further colored than the pre-restoration image caused by the brightness saturation generated by the intensity of solar reflected light. A false color "C" occurs when the edge part is further colored than the pre-restoration image caused by defocusing.
In the Wiener filter, the restoration degree lowers by setting a large value to the SNR value in Equation 1. The restoration degree starts dropping from a high frequency and the pre-restoration frequency characteristic cannot be reproduced even when the restoration degree is reduced. This is clear from the fact that M=1 is not established or the image restoration filter does not affect the image unless the SNR has a frequency characteristic in the Equation 1.
In order to adjust the restoration degree, JP 2007-183842 sets a parameter used to design the image restoration filter as in Equation 2:
                              F                                (                          u              ,              v                        )                          =                                                            α                                                                                H                                                              (                                              u                        ,                        v                                            )                                                        *                                            +              1              -              α                                                      α                                                                                                                H                                                                    (                                                  u                          ,                          v                                                )                                                                                                  2                                            +              1              -              α                                ×                      G                                      (                              u                ,                v                            )                                                          Equation                                                  2
F(u,v) and G(u,v) are Fourier transforms of the restored image and the deteriorated image, respectively. The adjustment parameter α provides a change from a filter that affects nothing (α=0) to an inverse filter (α=1), and the restoration degree of the image is adjustable in a range from the original image to the maximum restored image.
The image restoration method disclosed in JP 2007-183842 is a continuously adjusting method of the restoration degree including a reproduction of the original image. Apparently, this adjustment can successfully restraint generations of noises, ringing, and a false color. However, this image restoration method requires a recalculation of an image restoration filter and additional convolution processing to an input image whenever the parameter is changed.
In addition, since the deteriorated image is closer to the original image as the restoration degree is made lower, an aberrational component having asymmetrical blur again appears, such as the lateral chromatic aberration and the coma. The asymmetry of the aberration is caused by a phase shift for each frequency for forming the PSF. On the image, the coma degrades the image quality due to the deletion of an image, and the lateral chromatic aberration degrades the image quality through a chromatic shift. In particular, the lateral chromatic aberration is likely to stand out, and has conventionally been corrected as in a method disclosed in JP 06-113309. The method disclosed in JP 2007-183842 can correct the lateral chromatic aberration only when the restoration degree is high, and the lateral chromatic aberration becomes larger as the restoration degree is lower.
The adjustable restoration degree can restrain the problem, but increase the asymmetry of the aberration, such as the lateral chromatic aberration. In addition, the processing load increases because a lateral chromatic aberration amount varies and a correction amount of the lateral chromatic aberration needs to be changed in accordance with the setting of the restoration degree even when the lateral chromatic aberration correction processing is introduced in addition to the image restoration processing.

Image processing method, image processing apparatus, and image pickup apparatus for correcting degradation component of image


Secure outsourced aggregation of data using one-way chains is discussed in this application. Each input data source such as a sensor generates a Verifiable Synopsis (“VS”) which includes sensor data, an Inflation Free Proof (“IFP”) generated using a cryptographic function and a Self-Authenticating Value (“SEAL”) chain generated using a one-way function. An aggregator takes a plurality VSs from multiple data sources and aggregates them together into one. Maximum value, top-k, count, count distinct, sum, average, and other aggregate functions may be used. Folded VS provides a concise proof that no value greater than the maximum value was reported by a sensor, thus providing a check against deflation of sensor data. Similarly, the cryptographic function of the IFP provides a mechanism to prevent inflation of the sensor data. Thus it becomes possible at a portal to verify that aggregated data has not been inflated or deflated by the aggregator.

Every day the amount of data collected from a wide array of sources continues to grow. Sensors may acquire data ranging from temperature, air pressure, wave height, seismic activity, stock prices, commodity prices, and so forth. Where large numbers of sensors are employed, aggregators may receive and consolidate the data from sensors. These aggregators combine data, until a final parent aggregator generates a complete set of sensor data.
A portal, such as a server on the internet, may request information from an aggregator to fulfill a request. Unfortunately, it has traditionally been difficult to provide an assurance that information which has been aggregated has not been corrupted. Such corruption may occur because of system glitches or a malicious actor. Corruption may include increasing the reported value of a sensor ("inflation") or reducing the reported value ("deflation").
Various schemes have been put forth to try and secure aggregation. One scheme involves a single entity tightly controlling all aggregators, then making the assumption that these aggregators are not compromised. This scheme has several drawbacks. For example, an organization may not be able to afford the cost of maintaining such a system. Or the organization may not have the technical expertise or geographic reach necessary to maintain the aggregators.
Another scheme to secure aggregation involves the encryption of data at the sensor. This scheme has several drawbacks as well. For example, if the aggregator has the capability to decrypt data, typically considered necessary to aggregate the data, it gains the ability to tamper with the data before sending along to the portal. If the data is not decrypted at the aggregator, the portal is heavily loaded with the task of decrypting and aggregating data itself, removing the benefits of aggregators in the first place.
Thus, there is a desire to outsource aggregation while retaining the capability to determine if sensor data has been inflated or deflated.

Secure outsourced aggregation with one-way chains


A toilet seat handle assembly which may be readily and easily repositioned on toilet seats of a large range of widths without tools is described. The assembly has two facing clamps spanned by a bolt. The bolt threads into one of the clamps, but passes through the other clamp in such a manner that it slides upon the middle of the bolt. A handle threads onto the opposite end of the bolt, such that the second clamp slides over the bolt between the first clamp and the handle. With the clamps in position on the underside of a conventional toilet seat, bridging the inner and outer margins of one side of the seat ring, the handle may be conventionally rotated to tighten the clamps to affix the assembly. Thus, the handle serves the dual purpose of the installing and removal mechanism, as well as the handle for raising and lowering the toilet seat without the need for touching the seat itself.

It is understood that a commonly encountered problem in the use of the conventional toilet or water closet is that the user must touch the seat in order to raise and lower it onto the toilet bowl. Toilet seats, and particularly the undersides thereof, due to their proximity to the bowl, tend to be unsanitary, and few people, if any, disinfect them after use. This concern is particularly acute as regards public toilets.
A number of structures have been devised to assist in the raising and the lowering of a conventional toilet seat. However, most of these prior structures cannot be readily affixed to the toilet seat without tools, making them generally unmanageable or difficult for those not adept with tools. The positions of these handles also cannot be readily changed after they are installed.
For example, U.S. Pat. No. 1,999,555 describes a sanitary seat lift with a drip ridge, adapted to be screwed to the underside of a conventional water closet bowl seat. A toilet seat attachment held in place by a biasing spring web is disclosed in U.S. Pat. No. 3,191,193. While the springs certainly would hold the attachment in place for a time, it is anticipated that the spring wires would eventually fatigue and fail.
U.S. Pat. No. 3,717,884 mentions a lifting handle for a toilet seat, consisting of a plate-like flange which can be fastened to the underside of a toilet seat by screws, with a laterally projecting hand grip having top and bottom ribs in the form of closed loops. The bottom rib depends adjacent the toilet seat so as to act as a splash deflector. It is noted, however, that the lifter must be permanently affixed by means of screws.
A toilet operating assembly for protecting the hands of the use of a toilet against germs is described in U.S. Pat. No. 3,783,455. The device involves an operating assembly being adapted to attach to a toilet seat permanently by means of screws or the like, and includes a partially housed, vapor emitting wick, separating an operating handle and the toilet seat. U.S. Pat. No. 4,129,907 details a toilet seat operating assembly for protecting the hands of a user of the toilet seat against bacteria. The operating assembly is adapted to be permanently attached to a toilet seat, by means of screws, and includes a spherical hand-engaging portion which can be readily removed for cleaning and sanitizing.
A handle attachable to the underside of a toilet seat is disclosed in U.S. Pat. No. 4,805,246 for the purpose of manually lifting or lowering the seat in a sanitary manner. The handle includes an elongated member having an attachment portion securable to the edge marginal region of the seat and a handle portion cantilevered outwardly in position for grasping by the fingers of the user. A deodorant cake is mountable from the attachment portion and the handle portion, including a display area for carrying alpha/numeric or graphic representations in either flat, relief or raised orientation. A cover or sleeve may be inserted over the handle portion which is of sanitary composition or a band of sanitary material may be wrapped around the handle portion. Attachment is taught by means of adhesive tape. Even so, the attachment is considered permanent.
Also of interest is a toilet seat handle device for attachment to a toilet seat as an aid to raising and lowering the toilet seat without having to touch the seat, as described in U.S. Pat. No. 4,875,251. The handle is attached at one of its ends to the toilet seat and projects outwardly beyond the periphery thereof. Attachment may be made permanently by means of adhesive or screws.
By way of further, though less important information, U.S. Pat. No. 4,843,656 teaches a one-piece toilet seat comprising a rim having a central opening. The toilet seat rim has a front and back section. There is an imaginary axis passing through the front and back sections of the toilet seat rim. This axis lies generally perpendicular to the plane of the person using the toilet seat. The toilet seat rim possesses a lifting tab which extends from the rim outwardly of the rim, preferably at an acute angle to the axis. In this way, the toilet seat rim may be raised and lowered by grasping the tab.
It should be noted that all of the previous devices discussed above are permanently affixed and cannot be moved after attachment. Many of the handles require tools or special expertise for installation. Customers not handy with a screwdriver and/or a drill may have difficulty with these sorts of handles. Even those which do not require screws, such as those of U.S. Pat. Nos. 4,805,246 and 4,875,251, but which use adhesive for fastening cannot readily be removed after initial placement. Position adjustment is important for the installation of a toilet seat handle, since it is quite likely that after placement it is discovered that the position is inconvenient, for example, if the handle interferes with the natural position of the user's leg while the user is seated. Since during placement the installer is in a very different position than when using the toilet, he or she may very likely misjudge the proper position. Thus, a mechanism for quickly and easily adjusting the position of the handle would be greatly desired.
Only U.S. Pat. No. 3,191,193 seems to teach a toilet seat handle which can be quickly and easily placed. However, it is to be noted that device therein cannot be adapted to a wide variety of toilet seat widths, but is limited to a fairly narrow range of widths. While many commercially available toilet seats may come in a standard dimension, there is an increasing variety available on the market. Thus, it would be a useful advance in the art to provide a quickly repositionable toilet seat handle that would accommodate a large range of widths.

Repositionable toilet seat handle assembly