A method is described for containing dispersed particulate or soluble matter during contaminated sediment remediation operations in the marine environment. The preferred method comprises the use of a specially designed marine vessel that establishes a negative differential pressure gradient between a defined remediation control zone and the external ambient water environment, thereby preventing the release of contaminants dispersed during the remediation process. The preferred method also includes the use of marine vessels to remove contaminants contained within said control zone and to provide for the management of solids collected in the process.

This application relates to a process for isolating sections of the lakes, reservoirs, rivers, streams, and other water bodies so that contaminated sediments may either be removed or treated in-situ, while at the same time containing and preventing the release of particulate and soluble matter to the ambient water environment.
Removal of sediments that accumulate on the bottom of natural and artificial water bodies is commonly practiced to permit navigation of ships and/or to maintain designated water depths. This type of sediment removal is commonly referred to as maintenance or navigational dredging. Sediments are sometimes removed to clean up the bottom of these water bodies when such sediments are found to be contaminated and pose a threat to public health and/or the ecosystem. This type of sediment removal is commonly referred to as environmental dredging. In some cases the objectives of the sediment removal activity are both maintenance and environmental. The in-situ treatment of contaminated sediments to render contaminants inert without the need to remove the sediments from the waterway is another remediation approach that is being researched as an alternative to dredging. At the present time, however, sediment removal or dredging is the primary remediation method commercially practiced.
Current methods of maintenance or environmental dredging can be divided into two general categories. They include mechanical dredging and hydraulic or vacuum dredging. The fundamental difference between these categories is the equipment used and ultimately the form in which the sediments are removed. Mechanical dredges typically remove the sediments directly with clamshell-type buckets at a relatively low liquid to solid ratio (i.e., relatively little water is entrained in the sediments compared to hydraulic dredging operations). Hydraulic or vacuum type dredges agitate the bottom channel to dislodge the sediment, and pump (vacuum) the sediment from the waterway. In hydraulic dredging operations the sediment is transported in a slurry with water acting as the transportation medium. This results in a water sediment mix with a high liquid to solid ratio. The sediment in the slurry must later be segregated from the water carrier. This is typically accomplished using large impoundment areas where the sediment is extracted by settling and the water (effluent) is returned to the originating waterway.
The removal of bottom sediments, whether by a mechanical or by a hydraulic dredging operation, involves some form of raking, grabbing, penetrating, cutting, or hydraulically scouring of the waterway or channel bottom. During such operations, sediments are readily suspended into the water column, dispersed and lost. In addition to sediment loss due to sediment disturbance and resuspension, in the case of mechanical dredging operations, sediment loss will occur when the bucket leaks sediments due to improper bucket closure resulting from debris stuck in the bucket, inadequate bucket sealing mechanisms, and the displacement of water contained within the bucket that occurs when solids enter the bucket during the excavation. While hydraulic dredging operations may have the advantage of a vacuum system that can assist in capturing some resuspended solids during bottom scouring operations, the large volumes of water that must be withdrawn and processed during such operations limit the feasibility of hydraulic dredging operations to areas where large impoundments are available. In addition, the presence of tides and currents can be expected to significantly reduce the efficiency of capture of resuspended solids by vacuum dredges when compared to operations that occur in quiescent waters.
Sediment resuspension and loss during dredging is a particular concern in environmental dredging operations where sediments are contaminated and the resuspension and dispersion of such sediments can result in ecological and human health impacts. This concern is underscored by the fact that most contaminants are generally associated with or bound to the fine particles, which are also those particles that are most easily resuspended and dispersed during the dredging operation. In addition to particulate resuspension, the potential release of soluble contaminants that may be present in the pore space of contaminated muds or may be subject to dissolution from the mud particle upon resuspension during dredging operations is also a concern.
Other problems associated with environmental dredging operations include the lack of suitable methods to monitor the actual loss of sediment that occurs during the excavation process, the lack of appropriate methods to monitor and ensure that the cleanup is being properly effected, and the absence of suitable methods to make certain that the handling of such sediments, during marine-to-land transfer and land-based transfer of such materials, do not result in liquid leakage or loss of sediments.
Current approaches for monitoring sediment loss during the excavation typically involve the use of discrete upgradient and downgradient subsurface sampling stations. Water samples collected at these stations are used to assess the increase in solids or turbidity loading to the waterway during the excavation. Given the unpredictability of subsurface currents, the discontinuous dredging operation, and discrete (spike) loadings that can be expected during dredging operations, the collection of representative samples is difficult. In addition, a determination of sediment loss can only be made after the release has already occurred.
To achieve target cleanup goals at a contaminated sediment site, due to the resuspension and the redeposition of sediment that occurs during conventional mechanical and hydraulic dredging operations, second and third passes to clean the contaminated area are routinely common. Even with multiple passes of a contaminated area, targeted specifications are still difficult to achieve. Current methods to assess the effectiveness of the cleanup of the subsurface sediments after the excavation typically involve the collection of core samples at discrete locations in the dredge area. Due to the expected variability in the spatial distribution of contamination in bottom sediments, particularly after the sediment is disturbed in a dredging operation, the collection of representative bottom sediment samples is also a difficult proposition. If the remediation effort has not met the required specifications, dredging equipment must be remobilized and returned to the location for additional cleanup at significant expense.
The removal and management of contaminated sediments during environmental dredging operations is best accomplished by collecting the sediments in a secure manner, dewatering the sediments, and transferring the sediments in such a way that there will be little risk for spills or loss of material. In mechanical dredging operations, sediments are typically placed in solids barges that require off-loading facilities that make use of additional cranes and buckets to remove the sediments from the solids barge for land-based management. Such operations are extremely messy and difficult to manage, and present a relatively high risk for further environmental contamination. Hydraulic dredging operations, as previously noted, require the construction of facilities for collecting the slurry and segregating the solids from the slurry, and thickening and/or dewatering the collected solids prior to transport to the disposal site. These facilities must be constructed in close proximity to the dredging operation and also increase the risk of local environmental contamination.
Most of the advances in environmental dredging technology in recent years have focused on the development of improvements in the design of buckets or vacuum dredges that tend to reduce or control the disturbance of the bottom of the waterway during the sediment excavation process (Ouwerkerk, R. and H. Greve (1994). xe2x80x9cDevelopments in Dredges During the Last Decade.xe2x80x9d Pages 690-699 in Dredging ""94, Proceedings of the Second International Conference on Dredging and Dredged Material Placement, Edited by: E. C. McNair, Jr., American Society of Civil Engineers. 1994; Zappi, P. A. and D. F. Hayes. xe2x80x9cInnovative Technologies for Dredging Contaminated Sediments.xe2x80x9d Improvement of Operations and Maintenance Techniques Research Program, U.S. Army Corps of Engineers, Waterways Experiment Station, Vicksburg, Miss. Miscellaneous Paper EL-91-20. September 1991; and Herbich, J. B. Handbook of Dredging Engineering, McGraw Hill, Inc., New York. 1992).
The primary objective of most mechanical bucket modifications has been to create as tight a seal as possible on the bucket through the installation of rubber backing compressible seals and sensors (proximity switches) to ensure the bucket is closed prior to lifting in the hope of minimizing spillage. A dredging apparatus referred to as a xe2x80x9ccable arm clamshell bucket,xe2x80x9d advertised by Cable Arm Incorporated of Trenton, Mich., claims to reduce turbidity levels through its use of electronic sensors to detect bucket closure and compressible seals. While these types of systems offer improved designs, they do not eliminate the impact due to raking, upswell, and water displacement that will occur on excavation. In addition, such systems are incapable of effectively addressing leakage that will occur when debris is caught in the bucket and prevents full bucket closure.
Numerous modifications and subcategories of hydraulic dredges have been developed to attempt to mitigate problems associated with hydraulic dredging particle resuspension (Cleland, J. Advances in Dredging Contaminated Sediment, Scenic Hudson, Inc., 1997). Many have specific features that are designed to reduce sediment dispersion resulting from cutterblade, jetting, or raking mechanisms. None of these methods, however, have proven to be highly effective in areas where currents are present, nor do they significantly reduce or have suitable provisions for managing large volumes of contaminated water that are generated in the process. Large impoundment areas and suitable treatment methods are still needed to contain fine contaminated particulates that are drawn up with these sediments.
In addition to the use of improved mechanical or vacuum dredge systems, physical barriers such as silt curtains (flexible, impermeable canvas or rubber-like sheets that are deployed by attaching ballast to the bottom of the fabric and floats to the top to hold the curtain in a vertical configuration) or sheet piles have been employed during environmental dredging operations in attempts to isolate the area of dredging and contain contaminated particulates that are dispersed into the water column during the excavation process. These physical barriers do not prevent the migration of soluble contaminants. Silt curtains can provide some temporary particulate containment, but lack secure containment due to the porous nature of joints and curtain underflow, and their use in waterways with currents or tides is, in most cases, impractical. The application of fixed sheeting along the periphery of a dredge area is costly and, due to the porous joints of sheet piles, cannot guarantee complete particulate containment. Finally, while the referenced physical barriers provide some containment, once the barriers are removed the resuspended particles that were temporarily contained are free to migrate from the dredge area.
Although some advancement has been made in bucket or vacuum dredging, little progress has been made in developing physical barriers that effectively contain resuspended particulates or soluble contaminants during a dredging operation.
Smith, in his U.S. patent, Dredge Environ Protection Assembly, U.S. Pat. No. 4,386,872, Jun. 7, 1983, does describe an approach for temporarily isolating an area within a waterway during a dredging operation to prevent disturbed sediment from spreading. Smith proposes the use of a barge-mounted assembly where the barge (an open hopper barge) system is floated over the area to be dredged and a series of separate large side panel members (preferably xe2x85x9c inch thick steel, 24 feet long, and 18 feet high) are lowered from the barge to the river channel to isolate the dredge area. Smith""s invention requires that the area within the panels be pumped dry prior to the excavation. Smith further describes the use of panel support columns that would be lowered to a depth below the bottom necessary to resist the water pressure that would be exerted on separate side panel members. Smith""s invention provides for the use of a series of support column caissons (preferably 4 feet in diameter) that would be lowered to the bottom to support the entire vessel when the inner panel area is dewatered. Smith describes these caissons as xe2x80x9cstiltsxe2x80x9d to support the barge above the channel. Smith makes no mention as to how these caissons would support the barge on a soft muddy foundation, but does state that the columns would be lowered to a depth below the bottom surface of the waterway that would be required to support the barge. Smith describes in his patent how the panels would be lowered and set up end to end until they reach the bottom with fluid-tight seals located between the side panels and the panel support columns. Smith describes these fluid tight seals as xe2x80x9crubber sealing stripsxe2x80x9d to prevent infiltration of water through the panels into the dredge area.
Although Smith in his invention proposes equipment to physically separate the dredge area from the ambient water environment, Smith""s invention lacks practical utility. His plan to pump the area dry would exert significant hydrostatic pressure on his proposed sliding panel wall and its support structure. Smith fails to recognize that continuous pumping will almost certainly be required to maintain his dredge zone in the dry condition that his invention requires, and he does not address the disposition of the water that would be pumped from his dredge zone, which can be expected to contain contaminants.
Smith""s invention requires caissons to support the entire weight of the barge. This would necessitate that his support caissons be driven to a firm foundation such as bedrock. Such a foundation could be well below the bottom of the channel, further complicating the practicality of the invention. Smith does not describe any means to drive the panels below the initial placement depth in the event it becomes necessary to excavate deeper to remove additional contaminated sediment during a dredging operation. His proposed use of rubber sealing strips sandwiched between his panel support columns and panels, to prevent water infiltration, is theoretically plausible, but Smith fails to address how these strips would be attached nor how they would be sufficiently secure to withstand the abrasive forces they would encounter during deployment and redeployment of the side panels (if his system is to be mobile as implied). Smith does not address how the joints between multiple panels that lay one upon another, if needed, would be sealed.
Smith implies in his patent that an inclined non-horizontal bottom channel, which would result in a gap between the bottom panel and the inclined bottom surface, could be mitigated by attaching one or more extension panels to the bottom panel to block the flow of water. Smith states that such lower extension panels could be attached to the upper panels with bolts. Smith fails to address how these gaps would be identified, how the extension panels would be sized, and how bolts would be attached. One can only assume that Smith is considering the use of divers to bolt extension panels to all locations where gaps in the bottom seal are identified. Even so, Smith fails to address how these lower extension panels would be made watertight. Smith""s invention fails to account for debris such as logs, rocks, etc. that will invariably be encountered at the bottom of the channel at most dredge locations, preventing a side panel from fully penetrating the subsurface, thereby resulting in additional gaps under the panel. Large gaps would result in an inability to pump the inner dredge area dry, which is a key feature of Smith""s invention. In summary, the authors believe that Smith""s invention lacks the means to make it a practical mobile vessel for removing contaminated sediments in a dredging application.
Other inventors have focused their efforts on the development of physical barriers in the marine environment to contain spills or to provide dry areas for construction.
Santamaria, in his U.S. patent, Barrier for Water Treatment, U.S. Pat. No. 6,089,789, Jul. 18, 2000, describes a curtain barrier system that can be deployed to isolate two bodies of water for the purpose of treating the water contained on one side of the barrier without mixing of the two water bodies. Santamaria""s invention includes two flexible water impermeable curtains, similar to conventional silt curtains, that are deployed vertically, joined to a bottom web that contains ballast material to hold the barrier to the lagoon bottom and end anchors (on shore) to prevent the movement of the barrier.
While Santamaria describes in his invention a system to isolate two water bodies, Santamaria does not relate his system to a contaminated sediment dredging operation. His invention is intended to provide for the treatment of water on one side of an area of a lagoon that is separated from the remaining lagoon locations. Santamaria""s invention is similar to commercially available silt curtains that are held in place by a ballasted bottom and a buoyed float at the top. Santamaria describes features of his impermeable flexible curtain that differentiate it from silt curtains used in commercial applications. While Santamaria""s invention does provide some measure of separation, it cannot be used in the center of a channel where it cannot be anchored, nor would it be effective in sealing in a location where there are currents, and as such its application is primarily intended for a quiescent lagoon.
Strange, in his U.S. patent, Marine Pollution Containment Device, U.S. Pat. No. 4,889,447, Dec. 26, 1989, describes a containment barge consisting of two self-propelled semi-circular hulls that can be oriented in a manner that contains marine spills. The device described by Strange is designed as a rapid deployment device and provides for the mobile containment of oil spills at the surface. It does not extend vertically to the bottom of a channel, which would be necessary to address contaminated sediment dredging containment issues.
McClellan, in his U.S. patent, Mobile Cofferdam, U.S. Pat. No. 5,277,517, Jan. 11, 1994, describes a mobile cofferdam vessel that consists of a watertight rectangular shell that can be filled with water to submerge the cofferdam vessel in place, or have the water evacuated to float the vessel. The submerged vessel is designed to replace conventional stationary cofferdams that establish a zone that could be dewatered for use in constructing on the bottom of a waterway. McClellan describes the use of a pump to dewater the interior of the cofferdam to define a dry working environment.
McClellan""s invention is intended for construction of elongated structures (such as tunnels or piles) below a waterway where a physical barrier is submerged by sinking a physical structure at a desired location and dewatering the area inside the physical structure so that construction can take place. The application is not designed nor intended for contaminated sediment excavation and removal.
It is relevant to this invention that interlocking sheet piles are commonly used in the construction industry to act as barrier walls to prevent soil movement or to prevent or minimize liquid permeation. Typical sheet piles are comprised of individual steel plates that are vertically aligned with one another as they are sequentially driven into the ground. Interlocking joint connections are used to connect the sequentially aligned sheets.
While interlocking joint connections of conventional sheet piles effectively hold and align the sheets, they are not specifically designed to prevent seepage of water through the interlocking joint connection.
Reducing sheet pile seepage is important in applications where at least one of the objectives of the installation is to divert, intercept or control water flow. In most applications this flow is usually subsurface or groundwater flow. In the marine environment where contaminated sediments must be excavated and sheet piles are used as physical barriers to segregate the excavation area from the main water body, reducing sheet pile seepage rates is important.
There are several known methods for sealing sheet piles. Most of these methods make use of sealants, which are cement-based, bituminous-based, or consist of low permeability materials, such as bentonite or combinations of the above, to seal the voids in the sheet pile joint connection. Some related patents include Hunsucker (U.S. Pat. No. 3,302,412), Zanelli et al. (U.S. Pat. No. 5,163,875), Cherry et al. (U.S. Pat. No. 5,437,520). While many of the above inventions have the potential for sealing sheet pile joints, they also require special sheet pile construction and in addition cannot be reused once the sheet piles are removed (i.e., piles must be cleaned and the sealant applied each time the piles are used).
Wheeler and Harvey (U.S. Pat. No. 5,938,375) describe a method in which sealant material is inserted into a form-like housing that is designed to vertically align with the seam between adjacent sheet piles. Sealant material is inserted into this housing to reduce seepage. The housing is designed so that it may be installed on conventional sheet piles without the use of specialized sheets. While such is an advantage claimed by the authors of the patent, the use of applied sealants limits the potential for reusing the sheet pile if redeployment is required without having to clean and completely reseal the system.
Others have proposed the use of specially designed sheet piles with a variety of interlocking surfaces to increase the surface area contact between adjacent sheets and hence reduce seepage through the sheets. Some related patents include U.S. Pat. No. 5,320,454 and Wickberg and DeGrout (U.S. Pat. No. 5,921,796). While increasing surface contact will undoubtedly reduce seepage, once installed the removal of such sheets are extremely difficult so they tend to weld together and bind. Such an approach is not practical in applications that require installation and reuse of the sheet piles in a continuous operation.
As will be shown, the invention being disclosed in this application incorporates a novel approach that makes use of a new sealing system that can reduce flow through the seam of sheet piles installed in the water environment, and has particular application in the cleanup of contaminated sites where sheet piles are used to segregate the dredge zone from the ambient water body.
At the present time, essentially all contaminated sediment remediation strategies involve the removal of contaminated sediments via one or more of the aforementioned dredging methods. There are presently ongoing research efforts being conducted to seek methods for treating sediments in-situ. The primary objective of an in-situ treatment strategy is to chemically or biologically render the offending contaminants within the sediments inert, thereby eliminating the need for dredging. One of the major impediments to the implementation of such an in-situ treatment strategy is a system that can deliver and contain chemical or biological additives that might be used in such a treatment strategy and to prevent the migration of sediments that may be disturbed if the aforementioned additives are mixed with the sediments.
In addition to ongoing efforts to develop in-situ treatment technology, dredge muds present at the bottom of waterways are at times in a fluff-like form, making the mechanical excavation of such sediments extremely difficult. This is because a mechanical bucket will be scooping mostly water when attempts are made to excavate such a material. Just as the introduction of chemical or biological reagents can assist in rendering contaminants inert, it is possible to introduce conditioning agents that will promote the densification of fluff-like bottom muds to permit the more effective excavation of such sediments. Such a strategy, however, is also limited by systems that can isolate the area to be conditioned to avoid the loss of conditioning agents and disturbed sediments during the chemical delivery and mixing process.
In contrast to the prior art, the invention being disclosed herein relates to the development of a system that isolates a contaminated sediment area and produces a negatively pressurized control zone into which mechanical or hydraulic dredging apparatus can be placed and used to remove contaminated sediment or additives can be introduced to treat or condition the sediments. The invention does not require the dewatering of the subject dredge area. The invention does not require the use of large columns to support a vessel. The invention is not susceptible to large gaps in the barrier that would result in major water infiltration, and the invention provides a practical means to deploy and redeploy the vessel during continuous operations along a waterway. As will become apparent, the maintenance of this negatively pressurized control zone ensures a secure zone that prevents the release of both particulate and soluble matter, and can be readily monitored and evaluated to establish or certify that the operation (dredging or treatment) has met its specified objectives. These features are not included in the prior art. In addition to the establishment of the control zone, the inventors have included a new method for managing dredge solids removed by securing and stabilizing said solids at the dredging site to minimize the opportunity for spills associated with conventional solids management approaches.
It is therefore an object of the invention to provide for the removal or the in-situ treatment or conditioning of contaminated sediments from the bottom of lakes, rivers, reservoirs, and other water bodies in a manner that prevents the release and transport of particulate matter, soluble matter or additives from a contaminated site during dredging, treatment or conditioning operations.
It is also an object of the invention to establish boundaries of a control zone where the excavation, treatment or conditioning of sediments can occur in a contained manner.
It is a further object of this invention to make such a control zone mobile to permit redeploying the invention along a contaminated waterway.
It is a further object to establish a negative differential pressure between said control zone and the ambient water environment.
It is yet another object of the invention to establish such a negatively pressurized control zone by deploying a sealed, vertical barrier wall beneath a marine vessel and by pumping water from the inner volume of the control zone to establish a differential pressure gradient between the control zone and the ambient water environment.
It is also a further object of the invention that such a sealed, vertical barrier consist of sheets and sheet pile joint seals to respectively define the surface area and volume of the control zone, and to reduce the permeability through the joints of the sheets and hence the rate of flow required to establish said negatively pressurized control zone.
It is still a further object of the invention to treat water collected from the control zone, if necessary, during the pumping process with a polymeric membrane filtration treatment system to enable the discharge of this purified water back into the ambient environment.
It is yet a further object of the invention that such a polymeric membrane filtration treatment system be incorporated into a mobile water treatment vessel, to avoid the need for land-based facilities.
It is also a further object of this invention to incorporate mechanical and/or hydraulic dredging equipment for use within this control zone, if sediment removal is desired, to improve the effectiveness of the subsurface cleanup.
It is a further object of this invention to provide the means to contain all contaminated matter within said control zone and remove such matter until such time as the contaminated area can be certified as complying with the desired specification of the cleanup.
It is a further object of the invention to incorporate a dredge solids stabilization and transportation vessel that can manage the contaminated solids that are removed in a dredging process, and transport such solids to an off-loading facility in an environmentally sound manner.
In keeping with these and other objects of the invention, a system is described that provides for the containment of particulate and soluble matter within an isolated zone by the use of a specially designed marine vessel that establishes a negatively pressurized control zone that can be used with either mechanical or hydraulic dredging equipment to remove contaminated sediment, or with systems that can introduce and mix reagents into the contaminated sediments for in-situ treatment or conditioning purposes. The physical boundary of the control zone is established by deploying a vertical barrier wall in the form of sheet piles and impermeable sheet joint seals located within and below an open barge-like vessel.
While the use of sheet piles and impermeable sheet joint seals can assist in establishing the physical boundary of the control zone in which suspended contaminants are contained, the driving force used to ensure that neither soluble nor particulate matter is released from this zone during dredging, in-situ treatment or in-situ conditioning operations is provided by the introduction of a pumping system located inside the control zone. This pumping system withdraws water from the control zone to establish a negative pressure gradient directed toward the inside of the control zone from the ambient water environment. Development of this negative pressure gradient between the ambient water surface and the control zone water surface elevation ensures that all flow through the vertical barrier is into the control zone, thereby preventing the release of any liquid or particulate matter contained within the confines of the control zone into the ambient water environment.
Liquid pumped from the control zone, where agitation due to dredging, treatment or conditioning occurs, can be expected to contain contaminated particulate matter and, in some cases, soluble contaminants that must be treated prior to release into the ambient water environment. To achieve the appropriate degree of treatment for the collected water, the invention makes use of a polymeric membrane treatment system capable of removing particulate matter in the range of 0.01 to 10 microns, and soluble contaminant removal, if warranted.
Most polymeric membrane filtration systems in commercial operation at the present time utilize positive pressure as a driving force to pass liquids through the membrane. In recent years, immersed vacuum-driven hollow fiber membranes have been introduced commercially. An immersed hollow fiber membrane filter operating under negative pressure is a polymeric filter that achieves filtration by drawing water through a thin fiber (membrane) surface into the hollow annular inner core of the fiber. Either pressurized or immersed hollow fiber membrane filtration systems are suitable for use in the subject application.
Once the subject control zone is established, dredging can be undertaken using either mechanical or hydraulic dredging techniques, or reagents can be introduced and mixed with bottom sediments with assurance that any suspended material or soluble contaminants will be confined to the control zone or pumped out to the membrane treatment system for removal. As will subsequently be described, the preferred dredging operational mode makes use of both mechanical and hydraulic dredging equipment to remove contaminated sediments. The preferred in-situ delivery and treatment mode makes use of pumping and sediment agitation equipment to deliver the treatment reagent to the subsurface sediment, simultaneously mixing and disbursing the reagent within the sediment layer to be treated.
To minimize the pumping rate required to maintain a differential elevation and hence a negative pressure gradient between the control zone and the ambient water environment, the inventors have developed a specially designed sheet pile joint seal that is designed to reduce the flow of water through the joint between the individual sheet piles. The sheet pile joint seal included in the invention consists of a flexible shroud and a sealing tube that is deployed from the vessel and slides down the outer portion of the vertical barrier wall to secure each sheet pile joint. Pressurization of the sealing tube, by use of water pressure or air pressure or both, is used to achieve a seal that substantially reduces seepage through sheet pile joints deployed in a water column. The effectiveness of the seal is enhanced by the established pressure gradient, which acts to force the flexible shroud and sealing tube into the sheet pile joint, thereby reducing the flow of water through the joint.
To provide the means to effect the removal, treatment or conditioning of contaminated sediments, and to treat the collected water and manage all sediments without the need for land-based facilities in the vicinity of the cleanup, the inventors have further developed a system in which all components of the subject invention are adaptable to mobile marine vessels. This includes the specially designed control zone vessel, referred to as a contaminated sediment remediation vessel, the membrane water treatment system, and the solids stabilization and transportation system.
The system and vessels included in the invention are designed to provide mobile platforms that can readily be deployed and redeployed in order to provide for ongoing remediation over an extended length of contaminated waterway.
While other inventors have proposed physical barriers for separating a dredging area from an ambient waterway to prevent the escape of contaminated particulates, no prior inventions consider the use of a low pressure control zone that is not dewatered to achieve said objective. No prior invention considers the possibility of treating water pumped from said control zone to remove soluble contaminants that may be released during the excavation. No prior invention makes use of sheet piles deployed from a mobile vessel as the vertical barrier wall with the means to penetrate the channel bottom and bottom debris if necessary to achieve a bottom seal. No prior invention provides for individual sheet pile joint seals that can readily be deployed to the desired depth, and can assist in sealing the low pressure control zone to prevent the outflow of contaminants and reduce the inflow of water into said zone. No prior invention provides the means to readily deploy and redeploy a vertical, low permeability barrier in a practical manner during a cleanup operation. No prior invention provides the means to introduce and mix additives to treat or condition sediments, in-situ, in a contained manner. No prior invention provides the means to manage solids without land-based solids handling facilities near the dredge site.

Contaminated sediment remediation vessel

c/o Chesner Engineering, P.C. 2171 Jericho Turnpike


A thermoplastic molding composition suitable for making articles having good combination of properties is disclosed. The composition contains

The present invention relates to thermoplastic molding compositions and in particular to compositions containing polycarbonate resins.
A thermoplastic molding composition suitable for making articles having good combination of properties is disclosed. The composition contains
(A) a copolycarbonate derived from compounds of formula (I)
wherein R1 to R4 independently of one another represent H, C1-C4-alkyl, phenyl, substituted phenyl or halogen, and compounds of formula (II)
wherein R5 to R8 independently of the others denote H, CH3, Cl or Br and X is C1-C5-alkylene, C2-C5-alkylidene, C5-C6-cycloalkylene, C5-C10-cycloalkylidene, and (B) a homopolycarbonate derived from bisphenol A. The composition that features resistance to stress cracking and good low-temperature properties is suitable for automotive construction and exterior applications.
For automotive construction and other exterior applications, polycarbonates have long been sought that are as resistant as possible to chemicals and are preferably transparent and that are both resistant to low temperatures and are thermally stable. Transparent polycarbonates are therefore required that exhibit improved low-temperature strength compared with polycarbonate of pure 2,2-bis(4-hydroxyphenyl)propane, and have increased thermal stability, while having improved stress cracking behavior.
Copolycarbonates based on 4,4xe2x80x2-dihydroxydiphenyl and 2,2-bis(4-hydroxyphenyl)propane are already known from JP-A 5117382 and have been described in EP-A1 0 544 407, U.S. Pat. No. 5,470,938, U.S. Pat. No. 5,532,324 and U.S. Pat. No. 5,401,826 as being particularly resistant to chemicals, resistant to heat and flame retardant, while having the same mechanical properties and transparency as commercially available polycarbonate of pure bisphenol.
German Patent Application DE 10047483.7 describes copolycarbonates of 4,4xe2x80x2-dihydroxydiphenyl and 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) that exhibit particularly good low-temperature properties. However, it is also described that the good low-temperature properties diminish as the content of 4,4xe2x80x2-dihydroxydiphenyl falls. Since 4,4xe2x80x2-dihydroxydiphenyl is an expensive component in comparison with 2,2-bis(4-hydroxyphenyl)propane, it is desirable for reasons of cost to keep the 4,4xe2x80x2-dihydroxydiphenyl content as low as possible, without losing the desired improvement in the low-temperature strength.
The object was, therefore, to reduce the amount of 4,4xe2x80x2-dihydroxydiphenyl (DOD), or compounds of formula (I), necessary to prepare a particular amount of the polycarbonate, without thereby losing the desired properties of the polycarbonate.
Surprisingly, it has now been found that it is possible to produce blends of copolycarbonates containing DOD, or compounds of formula (I), and polycarbonate of pure bisphenol A that exhibit the desired properties of the copolycarbonate (A) unchanged, while the amount of DOD or compounds of formula (I), based on the amount of end product, is reduced.
That is particularly astonishing given that it is generally not possible when producing blends to predict what properties a blend will ultimately have. The properties of the starting polymers may be enhanced, eliminated, may change (in either direction), and in some cases the starting polymers may not even be miscible homogeneously, etc. In short, no prediction is possible and a result like the present result is in no way obvious but, on the contrary, is highly surprising.
Accordingly, the present invention relates to a thermoplastic molding composition containing (A)1 to 99 wt. % of copolycarbonate derived from 0.1 mol % to 46 mol %, preferably from 11 mol % to 34 mol % and especially from 26 mol % to 34 mol %, of compounds of formula (I)
wherein R1, R2, R3 and R4 independently of one another represents H, C1-C4-alkyl, phenyl, substituted phenyl or halogen, preferably H, C1-C4-alkyl or halogen, and particularly preferably all represent the same radical, especially H or tert-butyl, and complementary amounts, that is from 99.9 mol % to 54 mol %, preferably from 89 mol % to 66 mol % and especially from 74 mol % to 66 mol %, of compounds of formula (II)
wherein R5, R6, R7 and R8 independently one of the others denote H, CH3, Cl or Br and X is C1-C5-alkylene, C2-C5-alkylidene, C5-C6-cycloalkylene, C5-C10-cycloalkylidene, as bisphenol monomers, and
(B) 1 to 99 wt. % of a bisphenol A-derived homopolycarbonate.
The molding composition is suitable for use in fields in which particularly good low-temperature properties are sought. Preferred mixtures of the copolymer (A) with polycarbonate (B) are from 30 to 95 wt. % of (A), very particularly preferably from 40 to 95 wt. % of (A), with correspondingly complementary amounts of polycarbonate (B).
Mixtures of polycarbonate (B) with copolycarbonates (A) in which the copolycarbonates (A) is present in amounts of 34 to 26 mol %, especially from 33 to 27 mol %, more especially from 32 to 28 mol %, very especially from 31 to 29 mol % and most especially 30 mol % of bisphenol monomer of formula (I), in each case supplemented by a complementary content of bisphenol monomer of formula (II), are very particularly preferred, and the invention relates thereto.
The indicated percentages of the bisphenol monomers relate to the total content of bisphenols in the polycarbonates, defined on the basis of 100%. Component B is a homopolycarbonate derived from bisphenol A.
Blends that have the compositions mentioned as being preferred, particularly preferred or very particularly preferred are preferred, particularly preferred or very particularly preferred.
The definitions, relative proportions and explanations given above in general or within the scope of preferences may, however, also be combined with one another as desired, that is to say between the respective ranges and preferred ranges. They apply correspondingly to end products as well as to preliminary and intermediate products.
Surprisingly, it has now been found that the polycarbonate blends according to the invention have good low-temperature properties. That is especially surprising because blends derived from only a small amount of bisphenol monomer (I) exhibit better low-temperature properties than the corresponding pure copolycarbonates (A) derived from the same amount of (I).
The blends may therefore be used to make molded articles wherever the properties profile of the polycarbonates known hitherto is inadequate, especially, for example, in the electrical sector and in the construction sector, for coverings or glazing, especially in the automotive sector as films, sheets, fittings or housing parts, but also in the optical field as lenses and data storage means, and also as commodity goods, and when increased dimensional stability under heat or chemical resistance are required at the same time as good low-temperature properties. In addition, they may also replace other materials in applications in which conventional polycarbonates could hitherto not be used because their low-temperature properties were not adequate therefor.
According to the invention, good low-temperature properties are to be understood as meaning, for example, without being limited thereto, good low-temperature strength, since conventional polycarbonates become brittle at low temperatures and thus tend to break and tear.
According to the invention, low temperatures are to be understood as being temperatures below 0xc2x0 C., particularly preferably below xe2x88x9210xc2x0 C., particularly preferably below xe2x88x9220xc2x0 C., very particularly preferably below xe2x88x9230xc2x0 C., especially below xe2x88x9240xc2x0 C. and very especially below xe2x88x9250xc2x0 C.
Preferred compounds of formula (I) are 4,4xe2x80x2-dihydroxydiphenyl (DOD) and 4,4xe2x80x2-dihydroxy-3,3xe2x80x2,5,5xe2x80x2-tetra(tert-butyl)diphenyl, 4,4xe2x80x2-dihydroxy-3,3xe2x80x2,5,5xe2x80x2-tetra(n-butyl)diphenyl and 4,4xe2x80x2-dihydroxy-3,3xe2x80x2,5,5xe2x80x2-tetra(methyl)diphenyl, with 4,4xe2x80x2-dihydroxydiphenyl being particularly preferred.
Preferred compounds of formula (II) are 2,2-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane and 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 1,1-bis(4-hydroxyphenyl)-cyclohexane, especially 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) and 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (bisphenol TMC), very particularly preferably 2,2-bis(4-hydroxyphenyl)propane (bisphenol A).
The copolycarbonate (A) may be derived from one or more compounds of formula (I).
Likewise, (A) may be derived from one or more compounds of formula (II).
The preparation of (co)polycarbonates is known.
For the preparation of polycarbonates by the interfacial process or the melt transesterification process, reference is made, for example, to xe2x80x9cSchnellxe2x80x9d, Chemistry and Physics of Polycarbonates, Polymer Reviews, Vol. 9, Interscience Publishers, New York, London, Sydney 1964, p. 33 ff and to Polymer Reviews, Volume 10, xe2x80x9cCondensation Polymers by Interfacial and Solution Methodsxe2x80x9d, Paul W. Morgan, Interscience Publishers, New York 1965, Chap. VIII, p. 325 and EP-A 971790.
According to DE-A 2 119 779, the preparation of copolycarbonates involving compounds of formula (I) takes place preferably in solution, namely by the interfacial process and the process in homogeneous phase. Preparation thereof by the known polycarbonate preparation process in the melt (so-called melt transesterification process) is also possible, which process is described, for example, in DE-A 19 64 6401 or in DE-A 1 42 38 123. Transesterification processes (acetate process and phenyl ester process) are also described, for example, in U.S. Pat. Nos. 3,494,885, 4,386,186, 4,661,580, 4,680,371 and 4,680,372, in EP-A 26120, 26121, 26684, 28030, 39845, 91602, 97970, 79075, 146887, 156103, 234913 and 240301 as well as in DE-A 1495626 and 2232977.
Copolycarbonate (A) and homopolycarbonate (B) may contain impurities caused by the synthesis. A high degree of purity is, however, desirable and is preferably sought.
The polycarbonate and copolycarbonate according to the invention may contain structural units derived from any of a variety of end groups. These end groups are introduced as chain terminators. Chain terminators within the scope of the invention are those of formula (III)
wherein R, Rxe2x80x2 and Rxe2x80x3 may each independently of the others represent H, optionally branched C1-C34-alkyl/cycloalkyl, C7-C34-alkaryl or C6-C34-aryl, for example butylphenol, tritylphenol, cumylphenol, phenol, octylphenol, preferably butylphenol or phenol. The chain terminators used in the making of copolycarbonate (A) may be either the same as or different from the ones used in the preparation of polycarbonate (B).
The individual components (A) and (B) may, independently of each other, contain small amounts of from 0.02 to 3.6 mol % (based on the dihydroxy compound) of branching agents. Suitable branching agents are the compounds suitable for the preparation of polycarbonates and having three or more functional groups, preferably those having three or more phenolic OH groups, for example 1,1,1-tri-(4-hydroxyphenyl)ethane and isatin biscresol.
In order to alter the properties, auxiliary substances and reinforcing agents may be added to the polycarbonate blends according to the invention. These include thermal stabilizers and UV stabilizers, flow modifiers, mold-release agents, flame retardants, pigments, finely divided minerals, fibrous substances, for example alkyl and aryl phosphites, phosphates, phosphanes, low molecular weight carboxylic acid esters, halogen compounds, salts, chalk, quartz powder, glass fibers and carbon fibers, pigments and combinations thereof. Such compounds are described, for example, in WO 99/55772, p. 15-25, and in xe2x80x9cPlastics Additivesxe2x80x9d, R. Gxc3xa4chter and H. Mxc3xcller, Hanser Publishers 1983.
Other polymers, for example polyolefins, polyurethanes, polyesters, acrylonitrile-butadiene-styrene and polystyrene, may also be mixed with the components of the inventive composition.
Such substances are preferably added to the finished (co)polycarbonate in conventional apparatuses, but, depending on requirements, they may also be added at a different stage of the preparation process.
The components (A) and (B) may have molecular weights (weight-average molecular weight) of 10,000 to 60,000, preferably 20,000 to 55,000, determined by measurement of the relative solution viscosity in dichloromethane or in mixtures of equal amounts by weight of phenol/o-dichlorobenzene, calibrated by light scattering. They may already contain additives or stabilizers, such as may also be added to the blends according to the invention.
The present Application relates also to the polycarbonate blends according to the invention themselves.
The polycarbonate blends according to the invention are thermoplastically processable in the conventional manner at temperatures of 240xc2x0 C. to 380xc2x0 C., preferably 260xc2x0 C. to 360xc2x0 C. Molded articles and films of any kind may be produced in a known manner by means of injection molding or by extrusion. The present Application relates also to molded articles and extrudates produced from the composition according to the invention.
The composition according to the invention are readily soluble in solvents such as chlorinated hydrocarbons, for example methylene chloride, and may thus be processed, for example, in a known manner to cast films.
The combination of properties such as dimensional stability under heat, good low-temperature properties and chemical resistance allows the thermoplastic composition of the invention to be used in a wide range of fields. The following may be mentioned as examples of possible applications of the blends according to the invention, this list in no way being limiting:
1. Safety glazing, which, as is known, is required in many areas of buildings, vehicles and aircraft, as well as the visors of helmets.
2. Production of films, especially ski films.
3. Production of blow-molded articles (see, for example, U.S. Pat. No. 2,964,794), for example 1 to 5 gallon water bottles.
4. Production of transparent sheets, especially of hollow-chamber sheets, for example for covering buildings such as railway stations, greenhouses and lighting installations.
5. Production of optical data storage means.
6. For the production of traffic light housings or road signs.
7. For the production of foamed materials (see, for example, DE-AS 1 031 507).
8. For the production of threads and wires (see, for example, DE-AS 1 137 167 and DE-A 1 785 137).
9. As translucent plastics having a content of glass fibers for lighting purposes (see, for example, DE-A 1 554 020).
10. As translucent plastics having a content of barium sulfate, titanium dioxide and or zirconium oxide or organic polymeric acrylate rubbers (EP-A 634 445, EP-A 269 324) for the production of transparent and light-scattering moldings.
11. For the production of precision injection-molded parts, such as, for example, lens holders. To that end, polycarbonates having a content of glass fibers are used, which optionally contain in addition approximately from 1 to 10 wt. % MoS2, based on the total weight.
12. For the production of parts for optical devices, especially lenses for photographic and film cameras (see, for example, DE-A 2 701 173).
13. As light transmission carriers, especially as fiber-optic cables (see, for example, EP-A1 0 089 801).
14. As electrical insulating materials for electrical conductors and for plug housings as well as plug connectors.
15. Production of mobile phone casings having improved resistance to perfume, aftershave and perspiration.
16. Network interface devices.
17. As carrier material for organic photoconductors.
18. For the production of lamps, for example in the form of headlamps, headlight lenses or internal lenses.
19. For medical applications, for example oxygenators, dialysers.
20. For foodstuffs applications, such as, for example, bottles, kitchenware and chocolate molds.
21. For applications in the automotive sector, where contact with fuels and lubricants may occur, such as, for example, bumpers, optionally in the form of suitable blends with ABS or suitable rubbers.
22. For sports articles, such as, for example, slalom poles or ski boot buckles.
23. For domestic articles, such as, for example, kitchen sinks and letter box casings.
24. For casings, such as, for example, electrical distribution cabinets.
25. Casings for electric toothbrushes and hairdryer casings.
26. Transparent washing machinesxe2x80x94bull""s-eyes having improved resistance to the washing solution.
27. Safety goggles, optical corrective spectacles.
28. Lamp covers for kitchen appliances having improved resistance to cooking steam, especially oil vapours.
29. Packaging films for medicaments.
30. Chip boxes and chip carriers.
31. For other applications, such as, for example, stable doors or animal cages.
Films in particular may be produced from the high molecular weight aromatic polycarbonate blends according to the invention. The films have preferred thicknesses of from 1 to 1500 xcexcm, particularly preferred thicknesses of from 10 to 900 xcexcm. The resulting films may be stretched monoaxially or biaxially in a manner known per se, preferably in a ratio of from 1:1.5 to 1:5.
The films may be produced by the known processes for producing films, for example by extrusion of a polymer melt through a slit die, by blowing on a film blowing machine, by deep-drawing or casting. It is possible for the films to be used on their own. It is also possible, of course, to use them to produce composite films with other plastics films by the conventional processes, all known films in principle being suitable as partners, depending on the desired application and final property of the composite film. A composite of two or more films may be produced.
In addition, the thermoplastic molding compositions (herein referred to as polycarbonate blends) according to the invention may also be used in other layered systems, such as, for example, in co-extruded sheets.


A splash shield for use in wound irrigation is provided. The splash shield includes at least one outlet area located along its rim so that irrigating fluid may flow from the splash shield. The splash shield is preferably oval-shaped with a substantially flat top adjacent to which is a receiver unit. The outlet area can be formed, for example, by contoured portions or by a generally V-shaped opening, each able to define a channel to enable the escape of fluid from the splash shield. The splash shield may be used in tandem with a syringe having a tip that is positioned in the receiver unit. Additionally, a basin can be provided for use during wound irrigation. The basin includes indentations to accommodate placement of a portion of the human body within the basin and an exit portion such that fluid in the basin can move in the basin to the edge of a table, bed, gurney or the like.

This invention relates to the field of medical instruments and more particularly to a medical device to prevent splashing of possibly infectious patient bodily fluids and tissues onto medical personnel during wound irrigation.
In the medical field, the treatment of lacerations frequently requires that the wound be cleansed prior to closure. This cleansing ensures the removal of any foreign matter such as glass, grass, gravel, dirt, metal particles and/or bacteria. Any and all of these contaminants foster infection if not properly removed from the wound. The cleansing process also removes blood from the wound such that the treating medical personnel may properly explore the wound to verify and complete necessary treatment prior to the closing of the wound.
The above cleansing of a wound is commonly performed by irrigation of the wound using a syringe and a hypodermic needle, or an intravenous catheter with a blunted stylet and where the catheter length has been cut. Typically, the catheter is of 18 gauge size. Typically, the syringe is filled with an irrigating fluid, the needle is directed toward the wound, and the plunger of the syringe is depressed. The irrigation stream from the syringe and catheter combination acts to mechanically dislodge any contaminants from the wound. One obvious drawback of this process is that inherent force of the irrigation stream necessary to cleanse the wound also creates splashing and misting of the irrigation fluid and the contaminated bodily fluid. This splashing increases the risk of infection from the patient to the medical personnel providing treatment.
One known syringe splash shield provides a circular cup with integral tap on the exterior portion for connecting to a standard syringe and integral threads on the interior for attachment of a standard needle hub. The size of the circular cup is such that the needle extends beyond the base plane of the cup. Thus, this design has the inherent disadvantage of being capable of only deflecting high-angle splashes from the wound area. Additionally, the use of a needle that extends beyond the base plane of a cup increases the possibility of stabbing the patient with the needle.
Another known syringe splash shield incorporates a bell-shaped housing for deflecting splashed fluids for use with a syringe but not a needle. While this design avoids the drawback of the aforementioned syringe splash shield with a needle, it too has disadvantages. The open, planar surface of the bell-shaped housing is such that if it is held above the surface of the skin, the housing only contains high-angle splash. As such, this design may fail to fully meet its objective. On the other hand, if the bell-shaped housing is used while contacting the patient, the contained fluid cannot escape and may linger in the wound area and frustrate the intended debridement.
Both of the above known syringe splash shields are defined by circular openings. While this shape may be more easily manufactured, they are less conducive to use on long, narrow portions of the body where lacerations often occur, i.e., forearms, biceps, or calves.
In view of these perceived deficiencies in known syringe splash shields, it would be beneficial to provide a splash shield that enables medical personnel to properly clean a wound while containing essentially all splashed irrigating fluid and contaminants. It would also be beneficial to provide a splash shield that allows the contained fluid to escape in a controlled manner. It would be additionally beneficial to provide a splash guard in a shape that would function ideally on all parts of the patient""s anatomy where a laceration may occur.
In accordance with the present invention, a wound irrigation splash shield is disclosed. The wound irrigation splash shield allows medical personnel to properly cleanse a wound while confining the irrigating fluid within the shield. The wound irrigation splash shield of the present invention is intended to be used in contact with a patient""s skin in the area surrounding the wound to prevent essentially all splashing of the irrigating fluid and other contaminants onto other parts of the patient""s body or the attending medical personnel.
The wound irrigation splash shield of the present invention is essentially an inverted shell having an open bottom bordered by a rim or bottom edge. The top portion of the shell contains an orifice that allows for the irrigating fluid to pass into the center of the shell. The orifice can be positioned along the shell surface to optimize the direction of the irrigating fluid stream toward the wound. The top portion of the shell may take the shape of a truncated shell such that the top portion of the shell is substantially flat. The orifice may be positioned on this flat portion at the top of the shell. Further, the orifice may be centrally located within this flat portion.
The orifice of the splash shield may be designed to accommodate a syringe such that the syringe fits naturally into a receiver adjacent to the orifice. The receiver and/or the syringe may be designed in such a way that the syringe may be fixedly inserted into the receiver and yet remain removable by exerting a small amount of force. In this way, the syringe may be held to the splash shield without external force and yet be easily removed to re-fill the syringe with irrigating fluid as necessary. In fact, the splash shield of the present invention may be packaged, sold, stored, and/or used with the syringe as a set.
The orifice of the splash shield may also accommodate a luer tip of a bottle filled with saline solution or other irrigating fluid. The bottle may include a cap which may be removed from the bottle, e.g., by twisting or snapping. The removal of the cap may expose the luer tip. The luer tip has a similar geometry to the syringe tip. In this way, the luer tip of the bottle may be inserted directly into the orifice of the splash shield. The bottle may have collapsible sides, for example, bellows, such that attending personnel need only to squeeze the bottle to expel the irrigating fluid from the bottle through the luer tip.
The splash shield of the present invention may be shaped so as to be more readily used on long, narrow portions of the patient""s body. For example, the shell may be substantially oval-shaped having a lateral dimension and a longitudinal dimension wherein the longitudinal dimension is greater than the lateral dimension. In one embodiment, the longitudinal dimension is at least 1.2 greater than the lateral dimension. The shape of the splash shield of the present invention may also be defined, at least in part, by the height of the splash shield relative to the longitudinal and/or lateral dimensions of the splash shield. In one embodiment of the present invention, the lateral width of the splash shield may be 1.5 times larger than the height of the splash shield. In another embodiment, the lateral width dimension could be about 2 times larger than height of the splash shield.
The bottom of the splash shield is formed with one or more outlet areas through which the combination of irrigating fluid and body fluids and/or tissues can escape for subsequent capture. In one embodiment, the outlet areas are defined using contoured portions. More specifically, the rim of the splash shield may include substantially flat portions and the contoured portions. The flat portions may be planar. The contoured portions can define channels or outlet area portions which allow the expended irrigating fluid to pass from the interior of the shell to the exterior of the shell. The irrigating fluid passing to the exterior of the shell may then be collected in various ways. For example, the fluid may be allowed to flow naturally to a pan or wound basin placed under the patient""s body part or may be collected using a suction device. The contoured portions and the associated channels may be further defined in size relative to other dimensions of the splash shield. For example, at least one contoured portion may be positioned on the rim along at least one length of the rim defining the longitudinal dimension. The length of the channel can be greater than one-half the maximum longitudinal dimension. The height of the channel may be less than one-fourth the height of the splash shield. Alternatively, the length of the channel can be less than one-fourth the maximum longitudinal dimension, while the height of the channel may be at least one-third the height of the splash shield. In another embodiment, the outlet area portions include one or more generally V-shaped openings or channels that interrupt the substantially flat, planar bottom portion. Unlike the contoured portions, these generally V-shaped openings are more concentrated in the middle of the longitudinal dimension of the splash shield and the open area portions extend a much greater distance from the bottom portion.
The splash shield may be used in tandem with the wound basin of the present invention. The wound basin is a walled receptacle with a central tray. The walls extend above the central tray to contain fluid deposited in the wound basin. The wound basin may have an exit extension such that the geometry of the basin is elongated in at least one direction. In this way, the fluid deposited within the basin may be directed toward a fluid disposal bucket which may be positioned beyond the treating surface. The exit extension may include an exit canal to allow fluid deposited in the wound basin to be removed from the central tray. At least one indentation, and preferably two or more indentations, may be formed in the walls at selected positions. The indentations are depressions in the wall such that the height of the indentations is less than the height of the wall, yet still extend above the height of the central tray. The width of the indentations may be greater than the typical wall thickness of the wound basin. The indentations allow medical personnel to place a portion of a patient""s body within the central tray without causing undue discomfort to the patient, while the basin will still be capable of retaining any fluid deposited within the basin. Multiple indentations may be formed in the wall of the basin in selected positions to accommodate various body parts in various positions.
Based on the foregoing summary, a number of worthwhile aspects of the present invention can be readily identified. A wound irrigation splash shield is provided that contains essentially all irrigating fluid and associated contaminants within the shield. The wound irrigation splash shield of the present invention includes channels along the rim of the splash shield for controlled removal of the spent irrigating fluid and other contaminants. In that regard, the bottom of the splash shield can remain in contact with the body part being irrigated since the irrigating fluid with possible contaminants can escape through the channels while the bottom is in contact with the patient. The wound irrigation splash shield of the present invention may also be formed in a shape that allows the splash shield to be easily used when treating wounds on a long, narrow portion of the patient""s body. The wound basin contains fluid deposited within it and directs it to a proper disposal container. Multiple indentations along the walls of the basin allow the containment of the fluid without sacrificing patient comfort. A wound basin with multiple indentations also may provide attending medical personnel more options of placement of a patient""s body part within the wound basin depending upon where the wound is in relation to that body part. Moreover, multiple indentations provide treating personnel with a selection of indentations such that obstacles, such as walls or medical devices, may be avoided when delivering the waste fluid to the disposal receptacle.


A waterbased heatset offset lithographic ink comprising water, polyamide resins or fumarated rosin resins, hydroxyethylethylene urea, a modified linseed oil, a dibutylated benzoguanamine, a pigment and p-toluene sulfonic acid.

The invention relates to water based ink compositions for use in heat set/offset lithographic printing processes.
The heat set printing process was first introduced in the 1950""s and is now well established in the printing industry for the production of magazines, catalogues and brochures. The process yields high gloss, high quality prints and involves oven drying of the printed product.
In high speed web-offset printing presses, ink is applied to both surfaces of the web substrate simultaneously. To dry the ink before the substrate contacts a solid surface, the printed or coated web is passed through a float or floater type oven under tension and floated between cushions of hot air. Upon leaving the oven, the web must be cooled before further processing, such as sheeting, folding, or rewinding. Thus, the web is passed over one or more chill drums or rolls, i.e., internally cooled drums which reduce the web temperature from about 93xc2x0 C. to about 32xc2x0 C. Thus, heat set inks must fulfill exacting criteria to meet the high speed of press runs, the oven drying and required subsequent chilling and still meet the print quality standards. Further discussion of heat set inks and the heat set printing process can be found at The Printing Ink Manual, edited by R. H. Leach and R. J. Pierce, paces 571-576, 5th edition, (Blueprint, 1993).
Generally, lithographic heat-set/offset printing inks predominantly contain petroleum distillates. The fountain solutions typically contain a desensitizer, salts, and glycols. The use of water based inks allows the printer to avoid many of these volatile organic components (xe2x80x9cVOCsxe2x80x9d) and their byproducts but requires additional equipment such as a humidity control chamber.
The offset lithographic printing process has always presented a unique challenge to ink formulators since the process utilizes a plan ographic printing plate, i.e. the image and non-image areas are in the same plane on the image carrier, and two fluids are concurrently utilized as discussed above. Water based inks have been developed, but remain slow drying and high in tack.
U.S. Pat. No. 5,725,646, which is incorporated herein by reference, describes a way of stabilizing a water based offset ink composition without drying up on a conventional multiple roller ink train using use a re-wetting agent, namely hydroxyethylethylene urea (xe2x80x9cHEEUxe2x80x9d). Since this re-wetting agent does not dry, it remains in the final film making it susceptible to poor water resistance. High levels of VOCs emanating from the oil-based ink and the aqueous fountain solution were reduced as was the difficulty in controlling the ink/water balance, while preserving the principal advantage of the conventional lithographic printing process, i.e. high surface energy differential between the image and non-image areas of the printing plate. However, the use of conventional re-wetting agents, such as glycols and glycol ethers not only imparts poor water resistance to the final film, but also increases the tack of the formulations, thereby limiting its use on high speed presses.
U.S. Pat. No. 6,444,021, which is incorporated by reference, describes a newspaper ink composition containing a humectant and a modified soybean oil based resin so as to eliminate the need for the humidity control (chamber) associated with water based inks while allowing the use of existing, multiple roller press set-ups. Drying problems remained however as the humectant takes longer to dry once the ink has printed on coated papers.
U.S. Pat. No. 6,444,022 B1 which is incorporated by reference, describes a modified linseed oil reacted with polyglycols. In this manner, the benefits of including HEEU in the composition could be obtained without sacrificing risking water washability. However, dry times remain higher than required for heatset/offset printing.
Thus, there exists a need for a heatset/offset printing ink which can be printed at high speed and dry quicker than the prior art referenced above while still maintaining low tack for ink transfer and water resistance after printing.
It is an object of the present invention to describe heat set ink compositions which preserve the advantages of current water based ink systems containing HEEU, such as elimination of VOCs in the pressroom, while also eliminating the need for a humidity chamber in a manner which does not rely upon modified soybean oil based resin. It is an additional object of this invention to allow the continued use of existing conventional multiple roller printing systems.
A water based heat set offset lithographic ink composition according to the present invention comprises: (a) water; (b) fumarated rosin resins; (c) a modified linseed oil; (d) hydroxyethylethylene urea; (e) a dibutylated benzoguanamine; (f) p-toluene sulfonic acid (PTSA); and (g) pigment. The present invention is also directed to a waterbased heatset offset lithographic ink composition comprising: (a) water; (b) polyamide resins; (c) hydroxyethylethylene urea; (d) a modified linseed oil; (e) a dibutylated benzoguanamine; and (f) pigment.
It has been found that the use of hydroxyethylethylene urea in conjunction with benzoguanamine resin or with certain polyamide resins allows the formulation of a water based heatset lithographic ink which can be used in existing conventional multiple roller systems without the aid of a humidity chamber. Once printed, the ink has excellent rub and water resistance.
Water
The water based printing inks of the present invention contain water to act as a rheology and/or a surface energy modifier of the ink composition and to enhance the water washability of the ink. The water may be an added component or be contributed by one of the other components of the composition such as residual water from a pigment flush or press cake.
Resins for Pigment Bonding
The fumarated rosin resin in the present invention is a binder bonded to a pigment. Suggested binders to which the selected pigment may be bonded include, but are not limited to, water-soluble polyamide resins, rosin resins, rosin salts, tall oil resins, methacrylic resins, styrene-acrylic resins, polystyrenesulfonic acid and its salts, and acrylic or vinyl emulsion polymers prepared from monomers selected from the group consisting of acrylic acid esters, methacrylic acid esters, acrylic acid esters of polyhydric alcohols, methyl methacrylate, styrene, vinyl styrene, and vinyl acetate, and mixtures thereof. Particularly preferred binders are polyamide resins specially developed for use in graphic arts compositions, such as those resins sold under the trademark GAX(trademark) such as GAX(trademark) 12-513, available from FitzChem Corporation, Elmhurst, Ill., U.S.A., and fumarated rosin resins, available from Akzo Nobel Chemicals, Inc., Chicago, Ill.
Rewetting Agent
The composition of the present invention includes hydroxyethyl ethylene urea as a rewetting agent. The hydroxyethylethylene urea (HEEU) improves flow and increases open time on the rollers. While not wishing to be bound by theory, it is believed that the HEEU rewetting agent serves as a plasticizer by providing surface continuity to the dry film on the substrate.
Modified Linseed Oil
The invention includes a modified linseed oil to address problems otherwise associated with the inclusion of HEEU such as poor water resistance. The modified linseed oil also helps to reduce the ink""s tack. The modified linseed oil according to the present invention comprises the reaction product of polyglycol and linseed oil.
The modified linseed oil according to the present invention may also include lithium ricinoleate, phthalic anhydride and triphenyl phosphate. Preferred modified linseed oils include DV 1469, manufactured by Reichold Inc., Durham, N.C.
Dibutylated Benzoguanamine
The composition of the invention includes dibutylated benzoguanamine. The dibutylated benzoguanamine of the invention crosslinks with HEEU. The dibutylated benzoguanamine. The presence of water prevents this crosslinking reaction when the ink is being transferred.
Preferred dibutylated benzoguanamine includes but is not limited to Watersol CPC 248, manufactured by Dainippon Ink and Chemical Corp of Japan.
P-Toluene Sulfonic Acid Catalyst
The composition of the invention includes p-toluene sulfonic acid to catalyze the reaction between the HEEU and dibutylated benzoguanamine.
Pigment
The pigment may be any of those which are suitable for formulating offset lithographic printing inks such as dry powder, flush, presscake or pigment dispersions. Such pigments include CI Pigment Yellows 1, 3, 4, 5, 12, 13, 14, 17, 55, 65, 73, 83, 97 and 98; CI Pigment Oranges 13, 16 and 46; CI Pigment Reds 2, 3, 4, 10, 12, 48, 48:1, 48:2, 53, 57:2, 81, 104, 146, 170 and 176; CI Pigment Greens 2, 7 and 36; CI Pigment Blues 1, 15:1, 15:2, 15:3, 15:6, 16, 29, 56 and 61; CI Pigment Violets 3, 23 and 37; CI Pigment Blacks 6 and 7; and CI Pigment Whites 6, 7, 18 and 26.
In general, it is preferred that the ratio of pigment to fumarated rosin resin binder is in the range of about 1parts pigment to about 2 parts fumarated rosin resin binder (1:2). It is preferred that the ratio be about 1 parts pigment to about 1 parts fumarated rosin resin binder (1:1). A person of ordinary skill in the art will recognize that the amount of fumarated rosin resin-bonded pigment present in the ink composition of the present invention will vary, depending on several factors, including the ratio of pigment to fumarated rosin resin binder, other components to be present in a specific ink composition and the desired opacity of the end product. However, particularly when the pigment: binder ratio is approximately 1:1, it is contemplated that the resin-bonded pigment is present in an amount of about 10-60 wt % of the composition. It is preferred that the fumarated rosin resin-bonded pigment is present in an a amount of about 25-50 wt. % of the composition.
Printing Ink
In the water based heat set/offset lithographic ink of the present invention, the water is present in amounts of about 5 wt. % to about 35 wt. % and more preferably in an amount of about 5 wt % to about 15 wt. %. The resin bonded pigment may be present in the amount of about 35 wt. % and more preferably in an amount of about 25 wt % to about 50 wt. %. The modified linseed oil is present in amounts of about 5 wt. % to 30 wt. % and more preferably in an amount of about 10 wt % to about 20 wt. %. The hydroxyethylethylene urea is present in amounts of about 5 wt. % to about 20 wt. % and more preferably in an amount of about 10 wt % to about 20 wt. %. The dibutylated benzoguanamine is present in amounts of about 5 wt. % to about 20 wt. % and more preferably in an amount of about 10 wt % to about 20 wt. %. The p-toluene sulfonic acid is present in an amount of about 1 wt. % to about 5 wt. % and more preferably in an amount of about 1 wt % to about 2 wt. %.
Printing plates for use with the printing ink of the present invention should have image areas hydrophilic in nature with non-image areas hydrophobic in nature. An example of a suitable printing plate is the xe2x80x9cwaterlessxe2x80x9d Toray type. However, the image area of the plate need not contain a photo polymer. The image area of the plate may comprise, e.g. a grained aluminum surface which has no coating thereon, but is hydrophilic in nature. While the non-image area of the plate must be hydrophobic in nature, it may merely be covered with any type of hydrophobic material, provided that such hydrophobic material adheres to the non-image area of the plate during the printing process.
Water based metal driers may also be used in printing inks of the present invention. Previously, such driers could not be added because they would destabilize the water based ink system. In the composition presented here, the ink remains stable in the presence of such driers due to the presence of amine and water.

Waterbased heatset offset ink compositions


An F connector for mounting to the prepared end of a coaxial cable by compression of portions of the connector into tight frictional engagement with the cable. The body and compression ring of the usual F connector are incorporated in a unitary, one-piece body having three axial sections. The first section surrounds and frictionally engages the outer surface of the post stem in the usual manner. The second section is spaced from the stem to provide an annular space for the shielding and outer dielectric layers of the cable, also in the usual manner. A third section of the body is joined to the second section by an area of reduced thickness. In a first disclosed embodiment, the body fractures at the area of reduced thickness in response to an axial force applied to the third section in the direction of the second section. The wall thickness of the third section tapers outwardly from the area of reduced thickness, whereby movement of the third section between the inner surface of the second section and the outer surface of the cable by the axial force subsequent to fracture applies a radially compressive force to the cable and provides the desired tight frictional engagement of the connector and cable. In a second embodiment, the third section includes two, axially spaced areas of reduced thickness. The portions of the third section adjacent these reduced thickness areas are folded into the area between the second section and the cable as the axial force is applied, rather than being fractured.

The present invention relates to connectors for installation on a terminal end of a coaxial cable as used, for example, in CATV applications by radial compression of the cable by a deformable body portion of the connector. More specifically, the invention relates to compression-type connectors wherein the number of parts is reduced and manner of effecting compression is different from conventional, prior art connectors of this type.
A common type of connector installed on a terminal end of a coaxial cable includes elements known as a post, a nut, a body and a compression ring. The post includes a hollow stem integrally joined at one end to a flange. The nut is rotatably secured to the post, typically at or near the junction of the stem and flange, and the body surrounds the stem with a first portion, near the nut, in frictional engagement therewith and a second portion in outwardly spaced relation thereto. The compression ring, a hollow, substantially cylindrical member, is initially maintained in engagement with the body by one end of the ring encircling the end of the body remote from the nut. The end of the coaxial cable is prepared by stripping away certain layers thereof at specified distances from the end of the central conductor. After the cable is xe2x80x9cpreppedxe2x80x9d the connector is installed by inserting the cable axially into the connector with the stem of the connector post being forced between the outer layer of conducting material and the woven mesh metallic shielding layer. The shielding layer and the outer dielectric layer are in the initially open, annular space between the stem and inner surface of the body. Installation is completed by axial movement of the compression ring over the body with tapered surfaces on one or both of these members causing radial compression of the body into tight, frictional engagement with the outer surface of the coaxial cable.
The prior art includes, of course, a wide variety of styles and configurations of compression connectors of this general type. A feature common to radial compression connectors, however, is the separate fabrication of the body and compression ring which provide the means of frictionally engaging the connector with the cable. A variation of this design is disclosed in U.S. Pat. No. 5,525,076 of Down wherein the connector body includes one or more grooves extending into and around its outer surface. As the body is axially compressed, a portion of the body wall at the groove(s) is forced radially inwardly, into the outer dielectric layer of the coaxial cable. This forms a moisture barrier around the surface of the cable and mechanically locks the connector and cable, but does not radially compress the body into tight frictional engagement with the cable in the manner of the prior art connectors alluded to above and the present invention.
It is a principle object of the present invention to provide a novel and improved coaxial cable connector of the radial compression type which requires fewer parts than typical prior art connectors of the same general type, thereby offering advantages normally associated with a reduction in part count of multi-element devices.
It is a further object to provide a connector which is mounted to an end portion of a coaxial cable by a novel method of operation.
It is another object to provide novel and improved means for mounting a connector to the end of a coaxial cable.
Other objects will in part be obvious and will in part appear hereinafter.
In furtherance of the foregoing objects, the invention contemplates a connector having an essentially conventional post and nut in combination with a novel body. The post has the usual, integral flange and stem portions and the nut is rotatably engaged with the post at the flanged end. The hollow body includes a first portion extending axially from a first end and having an inner diameter substantially corresponding to the outer diameter of the post stem, a second portion extending axially from the first portion and having a larger inner diameter, and a third portion extending axially from the second portion to a second end. The three portions are integrally formed as a single, molded part. In a first disclosed embodiment, the third portion is connected to the second portion by a wall section of reduced thickness. The third portion is of the same inner diameter as the second portion and tapers to a larger outer diameter from the position of smallest wall thickness toward the second end of the body. When the connector is installed on the cable, the stem extends between the metal shielding layer of the cable and the outer conducting layer in the usual manner with these two layers positioned in the space between the outside of the stem and inside of the second body portion. When an axial force is applied (by an appropriate tool) to the third body portion, tending to move it in the direction of the first portion, the wall fractures at the section of smallest thickness, allowing the third section to be forced between the second section and the outer surface of the coaxial cable. The tapered surface on the third section is wedged between the second section and the cable surface, thereby radially compressing the cable and causing tight frictional engagement of the connector and cable.
In a second embodiment, the third section of the body has two annular areas of reduced cross section, axially spaced from one another. The thickness of these sections is such, relative to the type and characteristics of the material from which the body is fabricated, that as axial force is applied to the third section, tending to move it in the direction of the second section, that the wall folds at both areas of reduced cross section. Thus, rather than fracturing the body wall, as in the first embodiment, the body remains in a single part, but with folded layers of the third body portion between the inner surface of the second body portion and the outer surface of the cable, producing tight frictional engagement of the connector and the cable.
The features of the invention generally described above will be more readily apparent and fully appreciated from the following detailed description, taken in conjunction with the accompanying drawings.

Compression connector for coaxial cable and method of installation


A xe2x80x9cdreltxe2x80x9d photoreceptor particularly for use in high speed production color printers employing a lightweight porous machinable mandrel made of a foam material as a means of mounting a flexible belt photoreceptor on a rigid and lightweight cylindrical base. This porous foamxe2x80x94like cylinder is provided with means to temporarily decrease its circumference in order to mount the flexible belt on it. The foam material can be any material that can be formed into a foam type solid structure and then machined to certain precision. Examples of such foam material include a metal foam, a polymer foam, a ceramic foam or a carbon foam.

1. Field of the Invention
This invention relates to photoreceptors for electrophotographic printing, and more particularly, this invention relates to a photoreceptor belt in combination with a cylindrical mandrel. Even more particularly, this invention relates to a photoreceptor belt removable attached to a lightweight cylindrical mandrel which is constructed of a machinable foam material.
The photoreceptor and cylindrical mandrel design of this invention is particularly well suited to replace the current belt or drum photoreceptor designs as presently used in electrophotographic printing machines. The present invention will help reduce various mechanical problems that are typically experienced in any electrophotographic apparatus that employs known combinations of a photoreceptor belt and cylindrical mandrel.
The photoreceptor and cylindrical mandrel design of this invention is particularly well suited for use in high speed production color printers, especially those printers that employ large drums which support the photoconductors. Large drums require large and heavy support structures for the drums.
2. Description of the Prior Art
In an electrophotographic mono-color printing machine an electrophotograpic process is employed in which a photoconductive member is charged to a substantially uniform potential. The charged portion of the photoconductive member is then exposed to a light reflected original document image. Exposure of the charged photoconductive member selectively dissipates the charge in the irradiated areas. This process records an electrostatic latent image on the photoconductive member corresponding to the informational areas contained within the original document being reproduced. After the electrostatic latent image is recorded on the photoconductive member, the latent image is developed by bringing it into contact with toner. The toner image on the photoconductive member is subsequently transferred to a copy sheet. The copy sheet is then heated to permanently affix the toner image to the sheet. Multicolor electrophotographic printing is substantially identical, although more complex than the mono-color printing process. In a multicolor process, after the photoconductor is cleaned of residual toner, the copying process occurs again.
Cyclic and tandem color copying processes dominate the art of color printing. In a cyclic multicolor printing process, successive latent images corresponding to different colors are recorded on the photoconductive member during each cycle. Accordingly, one photoconductive member is required in this type of machine. The photoconductive member is used repetitively for each color/cycle. Each single color electrostatic latent image is developed with toner of a color complementary thereto. This process is repeated a plurality of cycles for the difference colors in an image and the respective complementary color tone. Each single color toner image is transferred to the copy sheet and superimposed with the prior toner image. This creates a multilayered toner image on the copy sheet. Thereafter, the multilayered toner image is permanently affixed to the copy sheet creating a color copy. The primary attributes of a cyclic printing machine are its relatively low number of parts and its low cost. U.S. Pat. No. 4,583,991, herein incorporated by reference, describes a cyclic printing machine in which a sheet moves in a recirculated path and successive color toner images are transferred thereto.
A typical tandem printing machine uses multiple printing engines to transfer, in one cycle, different colored tone images directly to a sheet or to an intermediate surface for subsequent transfer to the sheet. The fast printing rate is the primary advantage of a tandem machine since all colors are printed in one cycle. However, the complex equipment of a tandem machine leads to a higher total cost.
U.S. Pat. Nos. 4,796,050 and 4,803,518, herein incorporated by reference, disclose tandem printing machines having a plurality of photoconductive drums arranged such that color separated light images of an original document are recorded thereon as electrostatic latent images. The latent images are developed into visible color images. A conveyor advances a sheet past each photoconductive drum. Visible color images are transferred from each photoconductive drum to the sheet and then fixed to the sheet.
Both cyclic and tandem printing machines can use drum or belt type photoreceptors. Disadvantages are encountered in the use of photoconductive belts because especially high speed production color printers require multiple large photoreceptors. These large size photoreceptors can range in size from four inches to fifteen inches in diameter and up to twenty-seven inches long. The substrate (mandrels) which support these photoreceptor belts are usually formed of aluminum tubes that are very heavy and quite expensive to produce. An available alternative to this type of substrate is a thin metal or plastic cylinder which slips over a core cylinder i.e., a (Drelt). The core cylinder can either be a part of the machine or a part of the photoconductor. In any case, this core is also usually very heavy. In the case of the core being part of the machine, these heavy cylinders must be rotated, and continually started and stopped. Due to their large diameter, this creates mechanical problems due to the momentum and inertia properties of the heavy core. Additional horsepower is required to drive these cylinders, and additional braking and control mechanisms are required for stopping or changing speed of the photoreceptor. In the case where the core is a part of the photoconductor, the weight is also a concern since this assembly must be constantly handled by technical representatives, and also shipped to various locations.
Accordingly, it is a primary object of this invention to provide a new and improved mounting apparatus (mandrel) for a photoreceptor which avoids all of the disadvantages outlined above. The new and improved mounting apparatus for a photoreceptor in accordance with the features of this invention is made of a very lightweight material that can also be precision machined; has particular use when mounting a flexible belt photoreceptor on a rigid cylindrical base support, thereby forming a xe2x80x9cdreltxe2x80x9d photoreceptor for use in high speed production color printers; and provides a new and improved mandrel from which a photoreceptor can be easily removed and replaced. In addition to these advantages the present invention provides a mounting apparatus for a belt photoreceptor or a rigid thin walled cylinder which supports a photoconductive material, i.e. a drum.
To achieve the advantages in accordance with the purpose of the present invention, as embodied and broadly described herein, the photoreceptor apparatus of this invention comprises a cylindrical mandrel having a photoreceptor belt attached thereto. Attached as used herein means the photoreceptor belt is substantially fixed in a place on the full circumference of the mandrel at the longitudinal surface by preferably an interference fit or other known method. Preferably, the means for attaching the belt to the mandrel comprises a retractable segment mechanism that is isolated against the photoreceptor belt to hold the photoreceptor belt in place. Preferably, the photoreceptor belt is a multilayered continuous belt. The photoreceptor apparatus in accordance with the present invention comprises a photoreceptor belt in combination with a cylindrically shaped mandrel to which the photoreceptor belt is adapted to be mounted, the mandrel or support for the photoreceptor being made of a machinable foam material.
An electrophotographic imaging process in accordance with the features of the present invention comprises charging a photoconductive member to a substantially uniform potential, said photoconductive member comprising a photoreceptor belt attached to a cylindrically shaped mandrel, the mandrel comprising a machinable foam material; exposing the charged photoconductive member to a light reflective image to dissipate portions of the charge; transferring toner to the charge; and transferring the toner to a copy sheet.
The photoreceptor used with the present invention is utilizable as a replacement for previously known photoreceptor drums in printing machines, for example U.S. Pat. No. 5,121,171 herein incorporated by reference.
The photoreceptor belt in the current invention can be any type. U.S. Pat. No. 4,265,990, herein incorporated by reference describes various acceptable belt photoreceptors.

Mandrel for a photoreceptor belt formed of a rigid machinable foam material