A process mass flow apparatus for measuring the mass flow rate of a powdered, granulated or otherwise substantially divided process solid, seeds, grains, or similar particulate materials includes a process material inlet, a process material outlet, a measuring chamber connecting the process material inlet and the process material outlet, comprising a movable element with a fixed axis of rotation located in the flow path of the process material and having attached to the axis of rotation a material flow sensor which provides a raw output signal corresponding to an unknown mass flow rate and a processor which contains an empirically derived calibration function for converting the raw output signal to an adjusted signal indicating the mass flow rate of the process fluid. A method is also disclosed for determining an unknown mass flow using an empirically derived conversion function, the function being derived by correlating the output signals of a mass flow instrument sensing the flow of a calibration material with the output signals of the mass flow instrument sensing the flow of the process material, as is a method for calculating the accumulated weight of material having passed through the measuring chamber during a period of time specified by the user.

The present invention relates to a flow meter and more particularly to a process gravity free fall flow meter for measuring the flow rate and accumulated weight of solid powdered, particulate or granulated materials or other solids of like nature such as seeds, grains and pellets passing through a measuring chamber.
The current state of the art in the area of the continuous measurement of flow rates and accumulated weights of solid particulate materials is limited primarily to four systems: Coriolis force flow meters, impact flow meters, flow meters based on electronic load cells, and turbine flow meters.
Of the four major classes of flow meters suitable for solid particulate materials, each can be found to have its limitations, the major examples of which can be related to the physical phenomena and forces involved in the principles of their functioning and in the complexity of mechanisms necessary for adequately controlling and compensating for the related problems and deficiencies.
As is well known to those practiced in the art, a Coriolis flow meter is a mass flow meter that measures the mass flow rate of material flowing in a flow tube supported at both ends by oscillating the flow tube and detecting a Coriolis force acting on the flow tube, said measured force being theoretically proportional to the mass flow rate of the material. The Coriolis force is detected as a difference of phases produced at symmetrical positions between the supporting points and the center portion of,the flow tube when the flow tube is driven alternately at its center portion in a direction perpendicular to the supporting axis.
In operation, the flow tube is electromechanically vibrated out-of-phase with respect to a balance tube which is provided to reduce the vibrations that would be associated with a single unbalanced flow tube. These vibrations impart a Coriolis acceleration to material flowing through the flow tube. The reaction force to this Coriolis acceleration results in a slight distortion of the vibration mode shape of the flow tube. This distortion is measured by sensors connected to, or associated with, the flow tube. The sensors may be either of the velocity or displacement type. The material flow rate is proportional to the time or phase delay between the signals generated by two such sensors positioned along the length of the straight flow tube. A single sensor may also be used. Output signals of the sensors are applied to electronic apparatus which derives the desired information, such as mass flow rate, for the material in the flow tube.
Among the problems encountered in the application of the Coriolis force for the accurate measurement of the flow rate of a material are those related to correcting errors caused by a differences in or changes in the density of the flowing material, differences in the temperature deformation of the materials comprising the flow tube, and differences in temperature in the flow tube and the resonant member. Other difficulties related to the practical functioning of Coriolis force flow meters will be apparent to those practiced in the art. The measures required to circumvent and overcome the various limitations of the Coriolis force-based systems tend to greatly increase the complexity, and therefore the cost, of such systems.
The impact flow meter is widely employed in industry due to its potential robustness and ease of insertion into flow systems. The systems are based on the measurement of one component (usually horizontal) of the force of impact imparted by the flowing material as it falls on an impact plate positioned in the general line of flow of the material of interest. The impact of the flowing material on the impact plate produces a minimal movement or distortion in the position of the plate. A sensor, force transducer or other mechanism transfers the limited movement or distortion of the impact plate to the appropriate sensing device and related electronic circuitry which then converts that signal to an instantaneous mass flow rate based on suitable calibration data.
While the theory of the impact mechanism is clear, in practice, there are several problems that can significantly affect the accuracy of the force measurement and, therefore, the calculated flow rate. Simple physics shows that the force imparted to the impact plate by falling material will be a direct function of the relative angle of impact on the plate. Any change in that impact angle produced by an improper installation of the device in the flow path or subsequent movement after installation will introduce significant errors in the calculation of the final flow rate. In addition, because the movement of the impact plate is very limited, the mechanism employed to sense and transmit the resultant impact force to the corresponding electronic circuits must by necessity be very sensitive. That sensitivity necessitates the use of measures to protect the sensing mechanism and/or correct for changes in the response of said device, all of which imply the need for more complexity and cost in the construction and operation of such devices.
In a typical configuration for such units, bulk material is allowed to fall from a defined height upon a deflector plate which has been arranged at an angle to the vertical, with the flexural moment generated in the process being determined within the flexible joint of the deflector plate. The deflector plate arrangements have certain defects which result in relatively severe inaccuracies in measurement in the case of one and the same bulk material and which make problematical use of the same unit for a variety of materials, such as in dosing processes. Because in most such units moments are measured, it is not only the impact force which is generated via changes in pulsing which is decisive, but also the specific location where the bulk material impacts the deflector plate. In this instance, considerable variations are possible, depending upon the nature of the material involved. Furthermore, the type of momentum transmission involved is essentialxe2x80x94the degree of force transmitted is greater in the case of elastic impact than with inelastic impact. The specific impact rate, which must be taken into consideration, also varies with the type of bulk material involved and the condition of the bulk material at a given moment. The units described generally provide satisfactory results with respect to the bulk material to be weighed only through extensive calibration and generally require frequent control of such calibration.
Devices based on electronic load cells are also common in industry due to their theoretical precision and adaptability to transport belts and related systems as well as direct static weighing. Electronic load cells devices, however, are found to be extremely sensitive to physical abuse, requiring frequent calibration and control to maintain accuracy and precision. In addition, they are relatively delicate and easily broken by misuse. Their accuracy is also dependent on their proper installation so that any dislocation or movement in their location can produce significant errors in the final result.
Turbine flow meter devices have found great application in the measurement of fluid flows, especially in pressurized gas flow measurements and in simple pumped liquids such as is found in gasoline pumps. In such applications, however, the fluid flow is generally relatively constant and there exists a natural resistance in the flow field that prevents any xe2x80x9cfree wheelingxe2x80x9d of the measuring turbine when the force of the flowing material changes. In free flowing systems such as those contemplated by the present invention, turbine flow meters are rare and those in existence must incorporate some braking mechanism to prevent xe2x80x9cfree wheelingxe2x80x9d of the turbine, since free fall systems will not have the natural braking mechanism present in a pumped fluid system. Such braking mechanisms routinely involve some mechanical and/or electromagnetic phenomenon that requires continual or periodic monitoring of the applied braking force to insure constancy of its action so as not to over compensate and thereby alter the resultant forces and introduce measurement errors, or to detect and compensate for variations in braking force due to wear, fatigue or changes in characteristics due to changes in temperature or other ambient conditions.
As will be seen by the following disclosure, most of the complications and disadvantages of the flow measuring systems currently known to the art can be simplified, overcome or avoided completely by the present invention.
In view of the foregoing description of the current related art, it is an object of the present invention to provide a process mass flow apparatus for measuring the mass flow rate of a powdered, granulated or otherwise substantially divided process solids, seeds, grains, or similar particulate materials comprising: a process material inlet, a process material outlet, a flow passage or measuring chamber connecting the process material inlet and the process material outlet, a process material flow sensor located in the measuring chamber which provides a raw output signal corresponding to an unknown mass flow rate, and a signal processor, computer, programmed logic controller (plc) or other device of a similar function known to the art which contains an empirically derived conversion function for converting the raw output signal to an adjusted-signal indicating the mass flow rate of the process material. An additional object of the invention is to provide a method for determining an unknown mass flow rate using an empirically derived conversion function, the function being derived by correlating the raw output signal of a mass flow apparatus sensing the flow of a calibration material with the output signal of the mass flow instrument sensing the flow of the process material and a method for calculating the accumulated weight of material having passed through the measuring chamber during a period of time specified by the user. The exemplary mass flow instrument may further include a flow control portion, which may comprise a control unit, a valve drive, a valve, or other control or warning device known in the art that responds to an electronic, visual, audio, or other signal form produced by said control unit as a result of the process of determining the flow rate and/or accumulate weight of process material passing through or having passed through the measuring chamber.
In accordance with another embodiment of the present invention, a method for determining an unknown mass flow rate of a process material flowing through a process mass flow apparatus is provided. The process mass flow instrument provides a raw output signal corresponding to mass flow of the process material through the process mass flow apparatus. The method comprises the acts of providing one or more calibration materials which may or may not be the same as the process material and providing a mass flow apparatus similar to the process mass flow apparatus which is used for calibration purposes. The calibration mass flow apparatus is calibrated using the calibration material or materials by allowing said calibration material or materials to flow through the calibration mass flow apparatus at various known mass flow rates and correlating the raw output signal with the corresponding known flow rate and subsequently deriving a flow rate conversion function by applications of mathematical regression analysis using procedures or computer programs well known in the art. The conversion function may be a linear, quadratic, or cubic polynomial function or other mathematical function suitable for the specific application. Included in the conversion function is a multiplication factor or final calibration factor that allows the user to fine-tune the characteristics between the process mass flow meter and the calibration mass flow meter. After the calibration function is determined it is programmed into the control unit of the process mass flow meter. Once the process mass flow meter is installed in its final position, a final calibration is carried out by passing process material through the mass flow apparatus at a known flow rate. The ratio between the known flow rate of process material and that indicated by the preliminary calibration, hereafter called the final process calibration factor, K, given by the ratio of the known process material flow rate, F2, to the indicated flow rate, F1, (K=F2/F1) is then employed as the final calibration factor which is entered into the control unit program by the user to complete the calibration process.
A typical calibration function for a preferred embodiment of the present invention would be of the form
Q=K*[(A*S3)+(B*S2)+(C*S)+D]
where Q is the flow rate of process or calibration material passing through the measuring chamber at the instant of signal conversion, K is the previously defined final process calibration factor, S is the value of the raw signal produced by the material flow passing through the measuring chamber, and A, B, C, and D are the derived coefficients for a polynomial regression best fit curve to the calibration data.
Another object of the present invention is to provide a means by which the user can carry out in a continuous way a control of the flow rate and accumulated weight of a granulated, powdered or other particulate material as it passes through the zone of measurement in a way that produces an appropriate signal allowing the calculation of flow rate and/or accumulated weight of material passed as well as offering the possibility of providing a signal that may subsequently be employed in the control of one or more related processes such as process feed, valves, motors, etc. The fact that the user can pass materials as diverse as grains, seeds, pellets, powders, etc., in a continuous way makes much more efficient diverse processes such as loading, transport, transfer, packaging, and the like. In addition, the present invention provides the ability to measure and control flow rates and accumulated weights of materials in fixed lines of transport, in dosing operations, for fiscal control operations, and in situations requiring portable operation all with a simple, easy to use apparatus.
The apparatus of the invention has a measuring chamber having a body comprising a flow tube or conduit having a rectangular, circular, elliptical, or other cross section through which the Solid material to be measured is directed. Within the measuring chamber is located a movable element with a fixed axis of rotation on which the passing solid material exercises a force or torque proportional to the mass flow rate of the solid material and acting against a constant restoring force applied to the axis or the movable lever device, said restoring force being such that the degree of rotational or linear movement imparted by the passing solid will be a function of the force imparted by the solid material due to gravitational forces in free fall or to momentum imparted to said process material by some mechanical means of material transport.
Attached to the axis of the movable lever assembly or to some other convenient part of said assembly is a digital or analog device that measures the angle of rotation of said movable element or some proportional value of the linear movement of said assembly. The raw signal from the digital or analog measuring device is passed to an appropriate electronic circuit that conditions the raw signal in a manner such that a properly programmed associated microprocessor, computer, programmable logic controller (plc) or other similar device receiving said signal converts said signal to an instantaneous flow rate based on a preprogrammed calibration function or table. An additional step in the program then employs an internal clock or other suitable device or method and the previously calculated instantaneous flow rate for calculating the accumulated weight of material having passed through the measuring chamber during the measuring process. If so desired, the raw signal and/or calculated flow rate or accumulated weight can be employed as a feedback signal for the control of appropriate valves, motors or other control devices as are well known in the art.
A particularly important embodiment of the invention is its applicability as a portable device for measuring and controlling the amount of solid material being extracted from or loaded into tanks, trucks, rail cars, ships or other containers or transport systems in a continuous manner, providing important information related to the rate of material transfer, partial weights of material transferred, and final total weights transferred from or to the point of interest to the user. In particular, an important embodiment of the present invention is its application in mobile field operations such as, for example, the loading of seeds, grains, or other bulk materials into trucks, rail cars, silos, etc., at the time of harvest, storage, or production.
A second important embodiment of the invention is its use in fixed process lines for which its compact design and potential for structural modification and custom design make it a particularly attractive alternative to similar products known in the art.
The invention described is notable for its ease of use and flexibility of installation, requiring no more than correct leveling and a simple in-place calibration process. Other factors related to the installation of the invention vary according to the place and form of use.

Process mass flow apparatus and method for measuring the mass flow of powdered and granulated solids as well as the accumulated weight of material passed during a specified time

Barrio Parque Corcovado, Villa Rumipal, Cordoba


Processes for producing colored toner particles are provided comprising mixing a monomer, a colorant and an initiator to form an oil soluble organic phase; dispersing this oil soluble phase in controlled size between 5 to 20 microns in a water phase, employing a suspending agent, for example polyvinyl alcohol; polymerizing, employing conventional suspension polymerization techniques; introducing a second monomer which is allowed to diffuse into the first polymer and consequently swells the polymer; introducing a water soluble initiator; and heating this reaction mixture to effect a polymerization of the second monomer and form the desired toner.

This invention relates in general to electrostatography and in particular to an electrostatographic developing material and a method for its production.
Electrostatography is perhaps best exemplified by the process of xerography as first described in U.S. Pat. No. 2,297,691 to C.F. Carlson. In this process, a photoconductor is first given a uniform electrostatic charge over its surface and is then exposed to an image of activating electromagnetic radiation which selectively dissipates the charge in illuminated areas of the photoconductor while charge in the non-illuminated areas is retained thereby forming an electrostatic latent image. This electrostatic latent image is then developed or made visible by the deposition of finely divided, electroscopic marking material, referred to in the art as "toner" to the surface of the photoconductor, which marking material conforms to the pattern of the electrostatic latent image. The visible image may then be utilized in a number of diverse ways. For example, the image may be viewed in-situ of the photoconductive insulator, fixed in place on the photoconductive insulator or transferred to a second surface such as a sheet of paper and fixed in place thereon as desired depending upon whether photoconductive insulating material is reusable as is the case with amorphous selenium photoconductive insulators or non-reusable as is the case with particulate zinc oxide-binder film type xerographic plates.
Although the original Carlson patent describes developing the electrostatic latent image by dusting it with various powders such as lycopodium, gum copal, cumarone-idene resin, various powdered dyes and the like, many other developing materials and techniques have been devised since that time. Some of the development techniques include brush development as described in U.S. Pat. No. 3,015,305 to Hall, powder cloud development as described in U.S. Pat. No. 2,918,900 to Carlson, liquid spray development as described in U.S. Pat. No. 2,551,582 to Carlson, immersion development as described in U.S. Pat. No. 3,010,842 to Ricker, loop development as described in U.S. Pat. No. 2,761,416 to Carlson and doner development as described in U.S. Pat. No. 2,895,847 to Mayo. However, it is more than likely that the commercial xerographic development technique most widely used today is the technique known as cascade development which is described in U.S. Pat. No. 2,618,552 to Wise. This development technique is carried out by rolling or cascading across the electrostatic latent image bearing surface, a developing mixture composed of relatively large carrier particles, each having a multiplicity of electrostatically adhering fine marking particles, known as toner particles, on its surface. As this mixture cascades or rolls across the image bearing surface, the toner particles are electrostatically deposited on the charged portions of the image and not on the uncharged background areas of the image. In addition, toner particles accidently falling on these non-imaged areas are physically removed therefrom by the electrostatic attraction of carrier particles which pass in close proximity to these unbound toner particles. The result of this development process is an excellent background-free copy of the electrostatic image made up of the toner particles electrostatically clinging to the image surface. As a general rule when any one of these development processes is used with a reusable electrostatographic plate, such as an amorphous selenium plate, the toner particle image is transferred to and fixed on a second layer such as a paper sheet in contact with the toner image by adhesive transfer, by electrostatic transfer as described in U.S. Pat. No. 2,576,047 to Schaffert. After the image is transferred from the surface of the amorphous selenium plate, the plate surface may be cleaned and it is then ready for reuse in a subsequent cycle. The toner resins are usually thermoplastics selected to have melting points significantly above any ambient temperatures which might be encountered (generally running above 180.degree. F) and these are fixed to the paper in most cases by radiant heat fusing).
Most other electrostatographic techniques use the above described or similar development methods employing the same type of marking material or toner, and differ only in the mode of forming the electrostatic latent image charge pattern which is developed. (See, for example, U.S. Pat. No. 2,576,047 to Schaffert and U.S. Pat. No. 3,064,259 to Schwertz). In another technique, for example, in U.S. Pat. No. 3,081,698 to Childress, a conductive screen with a plurality of apertures which define the image area to be reproduced is spaced opposite a conductive backing electrode and a potential is applied between this backing electrode and the screen such that when finely divided electrostatographic toner particles smaller than the apertures in the screen are applied to the surface of the screen opposite the backing electrode, the electrostatic field set up by the potential source causes the particles to move through the apertures in the screen to form a toner image on the backing electrode in the configuration of the apertures on the screen. Various surfaces may be interposed between the screen and the backing electrode so that the particle image may be intercepted and formed on such interposed surfaces. Regardless of the surface upon which the toner image is deposited, it may be fixed in place upon that surface or transferred to another surface and fixed thereon.
The common feature of all of these electrostatographic systems is that they employ the lines of force from an electric field to control the deposition of finely divided, marking material or toner on a surface, thus forming an image with the toner particles.
In addition to the developing powder or toner materials described in the original Carlson patent, a number of other toner materials have been developed which are especially valuable for use in the newer development techniques including the cascade technique described immediately above. Generally speaking, these new toner materials have comprised various improved resins mixed with different pigments such as carbon black. Some exemplary patents along this line include U.S. Pat. No. 2,659,670 to Copley which describes a toner resin of rosin-modified phenol-formaldehyde, U.S. Pat. No. 25,136 to Carlson which describes a xerographic toner employing a resin of styrene polymers and copolymers and U.S. Pat. No. 3,079,342 to Insalaco describing a plasticized styrene-methacrylate copolymer resin.
In the past, these toners have generally been prepared by thoroughly mixing the softened resin and pigment to form a uniform dispersion as by blending these ingredients in a rubber mill or the like and then pulverizing this material to form it into small particles. Most frequently, this division of the resin-pigment dispersion has been made by jet pulverization of the material. Although this technique of toner manufacture has produced some very excellent toners, it does tend to have certain shortcomings. For example, it generally produces a rather wide range of particles sizes in the toner particles. Although the average particle size of toner made according to this technique generally ranges between about 5 and about 10 microns, individual particles ranging from sub micron in size to above 20 microns are not infrequently produced. Furthermore, this is a batch process which tends to be slow, expensive, noisy and dusty. In addition, this technique of toner production imposes certain limitations upon the material selected for the toner because the resin-pigment dispersion must be sufficiently friable so that it can be pulverized at an economically feasible rate of production. The problem which arises from this requirement is that when the resin-pigment dispersion is sufficiently friable for really high speed pulverizing, it tends to form an even wider range of particle sizes during pulverization including relatively large percentages of fines. In addition, such highly friable materials are frequently subject to further pulverization or powdering when they are employed for developing an electrostatographic copying apparatus. All other requirements of electrostatographic developers or toners including the requirements that they be stable in storage, non-agglomerative, have the proper triboelectric properties for developing, form good images, do not film or soil the selenium plate and have a low melting point for heat fusing are only compounded by the additional requirements imposed by this toner forming process.
Accordingly, it is an object of the present invention to provide a process which will directly produce a colored particle in a range of particle sizes from 1 to 100 microns useful in electrostatographic reproduction systems.
It is another object of the present invention to provide a direct process for colored toner production which avoids the many cumbersome operational sequences heretofore required.
It is still another object to provide a process for toner production which enables low-melting resins to be employed as the major constituent of the toner.
It is a still further object to provide a process for toner production wherein the surface hardness of a low-melting resinous particle can be modified to produce a useful toner material.
Yet still another object of this invention is to provide a novel encapsulation system for providing toners.
These and other objects of the instant invention are accomplished, generally speaking, by providing a process for producing colored toner particles comprising mixing a monomer, a colorant and an initiator to form an oil soluble organic phase; dispersing this oil soluble phase in controlled size between 5 to 20 microns in a water phase, employing a suspending agent, for example polyvinyl alcohol; polymerizing, employing conventional suspension polymerization techniques; introducing a second monomer which is allowed to diffuse into the first polymer and consequently swells the polymer; introducing a water soluble initiator; and heating this reaction mixture to effect a polymerization of the second monomer and form the desired toner. It is found that at the second initiator, the water soluble initiator, generates a free radical which attacks the surface of the swollen polymer particle and promotes polymerization at the surface by reacting with monomer at the surface thereby decreasing the monomer concentration and causing the transport of monomer to the surface by diffusion. The process is found to be self terminating when the total amount of sorbed monomer has been converted to polymer at the surface, thus providing an encapsulated toner employing the toner encapsulation system of the instant invention.
Thus, the surface hardness of the polymer particles can be increased by admixing the monomer of a tough polymer such as styrene with the polymer particles prior to recovering with continuous agitation. After a period of time sufficient to enable the monomer to diffuse into the polymer particles as above recited, the water soluble polymerization initiator is admixed and the polymer particles and the polymerization conditions and thereafter the surface hardened polymer particles containing a coloring are recovered.
Any organic momomer can be suitably employed in the present invention. The selection of a particular monomer is dictated by the properties desired in the ultimate polymeric toner. Thus, for example, monomers having the characteristic vinyl C.dbd.C structure can be employed. Illustrative of such monomers are esters of saturated alcohols with mono and polybasic unsaturated acids such as alkyl acrylates and methacrylates, haloacrylates, diethyl maleate, and mixtures thereof; vinyl and vinylidene halides such as vinyl chloride, vinyl fluoride, vinylidene chloride, vinylidene fluoride, tetrafluoroethylene, chlorotrifluoroethylene and mixtures thereof; vinyl esters such as vinyl acetate, unsaturated aromatic compounds such as styrene and various alkyl styrenes, alpha-methyl styrene parachlorostyrene, parabromostyrene, 2,4-dichlorostyrene, vinyl naphthalene, paramethoxystyrene and mixtures thereof; unsaturated amides such as acrylamide, methacrylamide and mixtures thereof; unsaturated nitriles such as acrylonitrile, methacrylonitrile, haloacrylonitrile, phenylacrylonitrile, vinylidene cyanide, and mixtures thereof; N-substituted unsaturated amides such as N,N dimethyl acrylamide, N-methyl acrylamide, and mixtures thereof; conjugated butadiones such as butadiene, isoprene and mixtures thereof; unsaturated ethers such as divinyl ether, diallyl ether, vinyl alkyl ether and mixtures thereof; unsaturated ketones such as divinyl ketone, vinyl alkyl detone and mixtures thereof; unsaturated aldehydes and acetals such as acrolein and its acetals, methacrolcin and its acetals, and mixtures thereof; unsaturated heterocyclic compounds such as vinyl pyridine, vinyl furan, vinyl coumarone, N-vinyl carbazole, and mixtures thereof; unsaturated alicyclic compounds such as vinyl-cyclopentane, vinyl-cyclohexane and mixtures thereof; unsaturated thio compounds such as vinyl thioethers; unsaturated hydrocarbons such as ethylene, propylene, coumarone, indene, terpene, polymerizable hydrocarbon fractions, isobutylene and mixtures thereof; alkyl compounds such as alkyl alcohol, allyl esters, diallyl phthalate, triallylcyanurate and mixtures thereof.
Any suitable mixture of copolymerizable monomers of the type described above can also be used in the process of this invention.
Any suitable colorant, whether insoluble pigment or soluble dye, can be dispersed or dissolved in the organic monomer or mixtures of monomers to form the organic phase employed in the dispersion polymerization process of this invention. If desired, especially for photoelectrophoretic processes, photosensitive colorants can also be employed. Additionally, combinations of pigments and/or dyes can be employed to obtain specific coloration effects.
Suitable pigments for use in the present invention include, for example, carbon blacks, Algol Yellow, Pigment Yellow 6, Benzidine Yellow, Vulcan Fast Yellow GR, Indofast Orange, Ortho Nitroaniline Orange, Vulcan Fast Orange GG, Irgazine Red, Paranitraniline Red, Toluidine Red, Permanent Carmine FB, Permanent Bordeaux FRR, Romanesta Red, Pigment Orange R, Vulcan Fast Rubine BF, Lake Red D, Lithol Red 2G, Double Ponceau R, Calamine Red MB, Pigment Scarlet 3B, Acid Alizarine Red B, Rhodamine 6G, Rhodamine B Lake, Methyl Violet B Lake, Gentian Violet Lake, Quinizarin, Victoria Pure Blue BO Lake, Ethylviolet Lake, Phthalocyanine Blue B Pr, Pigment Blue BCS, Peacock Blue Lake, Brilliant Green B, and the like.
Typical photosensitive organic materials include substituted and unsubstituted organic pigments such as phthalocyanines, for example, copper phthalocyanine, beta form of metal-free-phthalocyanine; tetrachloro-phthalocyanine; and x-form of metal-free phthaocyanine; quinacridones, as, for example, 2,9-dimethyl quinacridone; 4,11-dimethyl quinacridone; 3,10 -dichloro-6,13-dihydroquinacridone; 2,9-dimethoxy-6,13-dihydro-quinacridone and 2,4,9,11-tetrachloroquinacridone; anthraquinones such as 1,5-bis-(beta-phenylethylamino)antraquinone; 1,5-bis-(3'-methoxypropylamino) anthraquinone; 1,2,5,6-di-(C,C'-diphenyl)-thiazole anthraquinone; 4-(2'-hydroxyphenylmethoxyamino)anthraquinone; triazines such as 2,4-diaminotriazine; 2,4-di-(1'-anthraquinonylamino-6-(1''-pyrenyl)-triazone; 2,4,6-tri-(1'-1'',1'''-pyrenyl)- triazone; azo compounds such as 2,4,6-tris (N-ethyl-p-aminophenylazo) phloroglucinol; 1,3,5,7-tetrahydroxy-2,4,6,8-tetra (N-methyl-N-hydroxyl-ethyl-p-amino-phenylazo) naphthalene; 1,3,5-trihydroxy-2,4,6-tri(3'- nitro-N-methyl-N-hydroxy-methyl-4'-aminophenylazo) benzene; metal salts and lakes of azo dyes such as calcium lake of 6-bromo-1 (1'-sulfo-2-naphthaylazo)-2-naphthol; calcium lake of 1-(2'azonaphthalene-1'-sulfonic acid)-2-naphthol; calcium lake of 1 -(4'-ethyl-5'-chloroazobenzene-2'-sulfonic acid)-2-hydroxy-3 naphthoic acid; and mixtures thereof. Other organic pigments include polyvinylcarbazole; trisodium salt of 2-carboxyl phenyl azo (2-naphthiol-3,6-disulfonic acid; N-isopropyl-carbazole; 3-benzylidene amino-carbazole; 3-aminocarbazole; 1-(4'-methyl 5'chloro-2'-sulfonic acid) azobenzene-2-hydroxy-3-napthoic acid; N-2" pyridyl-8,13-dioxodinaphtho-(2,1-b; 2',3'-d)-furan-6carboxamide; 2-amino-5-chloro-p-toluene sulfonic acid and the like.
The x-form of metal free phthalocyanine is preferred because of its excellent photosensitivity and intense coloration.
Typical inorganic photosensitive compositions include cadmium sulfide, cadmium selenide, cadmium sulfo-selenide, zinc oxide, zinc sulfide, sulfur, selenium, antimony sulfide, lead oxide, lead sulfide, arsenic sulfide, arsenic-selenium, and mixtures thereof.
Any suitable dye or class of dyes may be used. Typical acid dyes include, for example, anthraquninone-C.I. Acid Blue 127, triphenylmethane-C.I. Acid Blue 103, azine-C.I. Acid Blue 98, xanthene-C.I. Acid Violet 9, nitroso-C.I. Acid Green 1, monoazo-C.I. Acid Yellow 29, diazo-C.I. Acid Green 20, xanthene-C.I. Acid Red 92, quinoline-C.I. Acid Yellow 3, diazo-C.I. Acid Orange 79.
Typical basic dyes include thiazole-C.I. Basic Yellow 1, ketone imine-C.I. Basic Yellow 2, acridine-C.I. Basic Yellow 4.
Typical dispersed dyes include nitro-acetamine Yellow 2 RZ-C.I. Disperse Yellow 1, azo-C.I. Disperse Orange 3, azo-Disperse Red 1, anthraquinone-C.I. Disperse Violet Celanthrene Red, anthraquinone-C.I. Disperse Blue 9, amino ketone-C.I. Disperse Green 1, azo-C.I. Disperse Black 9, C.I. Blacks 18, 19, 16, 1, 7, 12, 24, and 27; and diazo-C.I. Food Black 1.
The colorant can be dispersed in the monomer by admixing the colorant with the monomer under intensive agitation as obtained, for example, in a high speed, high shear mixer such as a Waring Blender equipped with a Polytron high shear head, a homogenizing mixer or the like, capable of a speed of from about 1000 to 3000 rpm. The amount of colorant added can range from about 2 to about 15 weight percent based on the weight of the monomer. Preferably, prior to dispersion of the colorant in the monomer, dispersing aids can be added to the monomer such as surfactants, dispersants and the like to assist in effecting a uniform dispersion. It has been found that increasing the viscosity of the monomer prior to addition of the colorant is an effective means of stabilizing the colorant dispersion. Typical oil soluble surfactants which can be employed to aid the dispersion of colorant are, for example, bis(trialkyl) esters of sodium sulfosuccinic acid, nonyl phenyl polyethoxy ethanol, dimethyl lauryl amine oxide, polyoxyethylene oleate, polyglycol stearate, polyethylene glycol oleic acid ester, and the like. Generally, from about 0.5 to about 1 weight percent surfactant based on the weight of monomer is sufficient. Stabilization of the colorant dispersion can be obtained by increasing the viscosity of the monomer-colorant dispersion through addition of a polymer soluble in the monomer. Generally, the most conveniently employed polymer is the polymer corresponding to the monomer employed; however, other polymers which are soluble in the monomer can also be suitable employed. Stabilization can be effected by addition of from about 1 to about 20 weight percent based on the weight of the monomer. A uniform dispersion of the colorant in the monomer can be effected by continuous high speed mixing for from about 10-20 minutes although longer or shorter periods can be employed depending upon the particular mixer employed.
Once the colorant/monomer dispersion is obtained, a polymerization initiator can be admixed therewith just prior to commencement of polymerization. Most conveniently, the polymerization initiator can be dissolved in a portion of monomer and the resulting solution can be blended with the colorant/monomer dispersion. Illustrative polymerization initiators which can be suitably employed are azobisisobutyronitrile (AIBN), benzoyl peroxide, methylethyl ketone peroxide, cumene hydroperoxide, 2,4-dichloryl benzoyl peroxide and the like. Generally, from about 0.5 to about 5 weight percent initiator based on the weight of monomer is sufficient.
In addition to the preparation of a readily polymerizable organic phase, the dispersion polymerization process of the present invention requires an aqueous phase containing a suspending agent. The aqueous phase can be prepared by dissolving a suspending agent in water with continuous agitation. Suitable water soluble suspending agents are, for example, water soluble polymers such as poly(vinyl alcohol), poly(ethylene oxide), methyl cellulose, hydroxyethyl cellulose, cyanoethyl cellulose and the like. Generally, from about 1 to about 10 weight percent suspending agent based on the weight of water has been found sufficient to effect a dispersion of the organic phase when said phase is admixed with the aqueous phase. Above about 10 weight percent, the resulting viscosity of the aqueous phase would generally be too high to enable the obtainment of the desired particle size. Preferably, 1 to about 4 weight percent suspending agent is employed.
After preparation of the aqueous phase, the aqueous phase can be charged to a reaction vessel and stirred at high speeds of from about 1000 to about 3000 rpm, while the organic phase is added thereto. Under these conditions, the organic phase is rapidly and uniformly dispersed within the aqueous phase as a plurality of particles having an average particle size ranging from 1 to about 100 microns. Generally, sufficient organic phase is added to the aqueous phase to effect a volumetric ratio of organic phase to aqueous phase ranging from about 0.05:1 to about 0.4:1, and preferably ranging from about 0.1:1 to about 0.2:1.
Upon completion of the addition and dispersion of the organic phase in the aqueous phase, the speed of agitation can be reduced to about 300 to 1000 rpm. The reaction vessel is then maintained at conditions sufficient to effect a rapid polymerization of the dispersion thereby avoiding the formation of a tacky particulate phase. Polymerization can be rapidly effected at a polymerization temperature of 60.degree. to about 90.degree. C under subatmospheric, atmospheric or super atmospheric pressure. Preferably, and most conveniently atmospheric pressure or autogenously generated pressures can be employed. Under these polymerization conditions, the reaction will be complete within from about 1 to 4 hours. Higher or lower temperatures can be employed depending upon the particular polymerization initiator employed.
When using carbon black as the colorant, initiation of polymerization sometimes becomes complicated because of the ability of the carbon black to trap the free radicals generated. AIBN, however, has been found to be an effective initiator even with carbon black.
Upon completion of the polymerization, the polymerized particles can be recovered by cooling the reaction vessel to room temperature while stirring continuously to prevent agglomeration. Thereafter, the reaction medium can be thoroughly washed with water to remove the suspending agent and the particles can be recovered by filtration and drying. If desired, after washing, the aqueous dispersion can be freeze dried to recover the particles.
It is considered preferable in order to obtain free flowing particles, that blocking or agglomeration of the particles due to moisture sensitivity be avoided. Moisture sensitivity is sometimes imparted to the particles during polymerization by grafting thereon of the suspending agent as, for example, poly(vinyl alcohol) can be grafted to the particulate polymer during the polymerization reaction. The particles can be made moisture insensitive by treating with an insolubilizer such as melamine formaldehyde resins, toluene diisocyanate, dimethylolurea and the like. This can be conveniently accomplished by dipping the particles in a bath of the hardening agent or through use of a spray of said hardening agent.
In instances wherein the monomer selected for use in preparation of the ultimate toner resin provides a low melting polymer, it may be desirable to provide a means for surface hardening of the particle to enhance its use as a toner particle under the relatively rigorous conditions encountered in conventional electrostatographic and photoelectrophoretic processes.
Surface hardening of the toner particles can be affected after the initial polymerization reaction by first removing any residual initial initiator present in the reaction system. This can be easily accomplished by heating the reaction system at temperatures ranging from about 60.degree. to 90.degree. C for a sufficient period of time to remove the initiator. The actual period of time will vary depending upon the half life of the particular initiator employed in the presence of the colorant, particularly carbon black. Generally, heating within said temperature range for about 4 hours has been found sufficient. Thereafter, 5 to about 10 weight percent based on the weight of particulate polymer of a monomer of a tough polymer such as styrene, methyl methacrylate, vinyl chloride, vinyl pyridine and the like is added to the reaction system with continuous stirring for a sufficient period of time to allow the monomer to diffuse into the polymer particles. Upon completion of the diffusion period, generally from about 0.5 to about 2 hours, from about 0.1 to about 10 weight percent of water soluble initiator based on the weight of monomer is added to the aqueous reaction system and polymerization is effected by heating the reaction system at temperatures ranging from about 60.degree. to 80.degree. C for about one hour with continuous agitation. Suitable water soluble initiators are, for example, potassium persulfate, ammonium persulfate, hydrogen peroxide, sodium perborate and the like. In this manner, polymerization is effected only at the surface of the toner particles thereby imparting surface hardening thereto.
Upon completion of the polymerization, the surface hardened toner particles can be recovered as described above; namely by washing the particles with water to obtain a clear aqueous slurry of the toner particles which can be filtered and dried or freezedried to recover the particles intact.
In this manner, uniform spherical toner particles containing a colorant which can be photosensitive can be readily obtained. Advantageously, the particles can be surface hardened in situ enabling the use of low melting resins which are desirable for rapid fusing operations.
The toner compositions obtained in accordance with the present invention can be admixed with solid or non-solvent liquid vehicles therefor to form electrostatographic developer compositions. In general, successful results have been obtained with from about 10 to about 200 parts by weight of either solid or liquid vehicle to about 1 part by weight of toner. Preferably, the vehicle to toner ratio ranges from about 50 to 1 to about 150 to 1. In such preferred compositions the vehicle acts effectively to remove any toner particles which might tend to adhere to a non-image area and the toner itself forms dense readily transferable and fusible images.
Solid vehicles are generally in the form of granular carrier particles which are grossly larger than the toner particles by at least an order of magnitude of size and are shaped to roll across the image-bearing surface.
Generally speaking, the carrier particles should be of sufficient size so that their gravitation or momentum force is greater than the force of attraction of the toner in the charged areas where the toner is retained on the plate in order that the granular carrier particles will not be retained by the toner particles, while, at the same time, the toner particles are attracted and held, or repelled, as the case may be, by the charged or uncharged areas of the plate since said toner particles acquire a charge of opposite polarity to the charge of both the granular carrier particles and the plate. It has been found best to use granular carrier particles of a size larger than about 10 microns, usually between 30 and about 1,000 microns, and toner particles of a size from about 1 to 20 microns. The granular carrier particles may, if desired, be somewhat larger or smaller as long as the proper size relationship to the electroscopic toner is maintained so that the granular carrier particles will flow easily over the image surface by gravity when the plate is inclined without requiring additional means or measures to remove them.
Typical carrier materials include: sodium chloride, ammonium chloride, potassium chlorate, granular zircon, granular silicon, methyl methacrylate, glass, silicon dioxide, flintshot, iron, steel, ferrite, nickel, carborundum, and mixtures thereof. Many of the foregoing and other typical carriers and described by L. E. Walkup et al, in U.S. Pat. No. 2,638,416 and E. M. Wise in U.S. Pat. No. 2,618,552.
When it is desired to employ a liquid developer composition, the toner compositions of the present invention can be incorporated in any conventional liquid vehicle which is a non-solvent for and non-reactive with the polymer and which has a volume resistivity above about 10.sup.10 ohm-cm and a dielectric constant greater than 2.5. In addition, the liquid vehicle should, if possible, be one which does not have an appreciable toxicity and which is not too flammable. It is also considered desirable to employ a liquid which is neither malodorous nor highly colored. It is preferred that the liquid vehicle be inert to the material which bears the electrostatic latent image to be developed. Suitable liquid carriers are, for example, kerosene, turpentine, benzene, cyclohexane, carbon tetrachloride, silicones, fluorinated hydrocarbons such as tetrachlorodifluoroethane, trichlorotrifluoroethane and the like. Other suitable liquid vehicles are described in U.S. Pat. No. 2,899,335.
In another aspect of the present invention, an electrostatographic process is provided which employs the developer compositions of this invention. The toner develops the electrostatic latent image on the image bearing surface and can be fused thereon or can be subsequently electrostatically transferred to a substrate and then fused on the substrate to form a permanent image thereon.

Method of producing toner particles by in-situ polymerization and imaging process


An in-the-ear (ITE) physiological measurement device (2) includes a structure (4) formed for easy insertion into multiple shaped and sized ear canals. An inflatable balloon (6) surrounds an end portion of the structure (4) to be positioned in the ear. Optionally, a mushroom shaped tip (22) is connected with an end of the structure (4) and carries a plurality of sensors (8). Inflation of the balloon (6) expands the tip (22) radially to position the sensors (8) proximate to vascular tissue within the ear canal. Once suitably positioned, the one or more sensors (8) sense physiological signals from the vascular tissue and bone structure.

The following relates to monitoring physiology. It finds particular application to an in-the-ear structure that is inserted in the ear canal to suitably position one or more physiological sensors within the inner ear to capture information indicative of physiological phenomena including blood pressure, respiration, perfusion index, blood oxygen, pulse rate, and body temperature, for example.
Physiological signals have been measured from within the ear. However, there are no multi-parameter physiological measurement devices that non-invasively measure blood pressure from within the ear. Examples of barriers that frustrate such development include the varying size and shape of the human ear canal from person to person, an inability to strategically position sensors within the ear canal to optimally receive physiological signals, and an inability to protect sensing devices from contamination through contact with inner ear tissue while measuring physiological signals.
In one aspect, an in-the-ear physiological measurement device includes a structure formed for insertion into an ear canal. One or more sensors are operatively coupled to a portion of the structure that is positioned in the ear. An inflatable balloon is operatively coupled to the portion of the structure positioned in the ear and inflates to position the one or more sensors proximate to tissue within the ear canal. Once suitably positioned, the one or more sensors sense physiological signals from the surrounding tissue and bone structure.
One advantage includes measuring physiological signals from within the ear.
Another advantage resides in non-invasively measuring blood pressure from within the ear.
Another advantage is continuously measuring non-invasive blood pressure from with the ear.
Another advantage resides in an in-the-ear device that forms to different shaped and sized ear canals.
Another advantage is positioning the sensor within the ear canal to optimally receive physiological signals therefrom.
Another advantage is positioning the sensor within the ear canal with ideal force and pressure to ensure close coupling of sensors with tissue without causing blanching of the tissue.
Another advantage is positioning the sensor within a well perfused physiological site even if the body is experiencing peripheral shutdown due to shock or other conditions.
Another advantage is the prevention of over insertion into the ear.
Another advantage is measuring physiological signals through a sheath that mitigates contamination of the physiological sensors.
Another advantage resides in an in-the-ear physiological signal measuring device that equalizes ear pressure with ambient pressure, especially during balloon inflation and deflation.
FIG. 1 illustrates an in-the-ear (ITE) physiological measurement apparatus 2 (hereafter "the ITE apparatus 2") for measuring one or more physiological signals (e.g., blood pressure, pulse, blood oxygen, perfusion, temperature, respiration . . . ) from within an ear canal. The ITE apparatus 2 includes a structure 4 that inserts into the ear canal. The structure 4 is dimensioned to enter the ear canal to a suitable depth and adapts to various shaped ear canals (e.g., different curvatures). That is, the structure 4 is small in diameter compared to the diameter of the ear canal. In a preferred embodiment, the structure 4 projects into the ear canal such that an end portion is positioned proximate to a bony region of the ear or other relatively quiet zone of the ear canal.
The end portion of the structure 4 residing in the ear canal includes an annular inflatable balloon 6. The inflatable balloon 6 surrounds the end portion of the structure 4 (as illustrated) or suitable portions thereof. The inflatable balloon 6 ideally supports one or more sensors 8 that are operatively coupled to a surface of the balloon 6 and that measure physiological signals. Suitable sensors include light emitting diodes (LEDs), an infrared (IR) source, light detectors, a pressure transducer, a microphone, and a thermistor, for example. The sensors 8 are strategically positioned on the balloon 6. For example, a light detecting sensor typically is positioned to minimize or prevent absorption of light not indicative of the physiological process under measurement (e.g., light from outside the ear, light emitted from another sensor located on the balloon 6 . . . ). Although depicted as circular in FIG. 1, the one or more sensors 8 can be any shape. Alternatively, the sensors could be mounted within the end portion of the structure 4 and could be moved into contact with the tissue once inserted into the ear.
The inflatable balloon 6 is inflated to position the one or more sensors 8 proximate to appropriate tissue within the ear canal with ideal force and pressure to ensure close coupling of sensors with tissue but without causing decreased perfusion or blanching of the tissue. For adult humans, this includes inflating the balloon 6 to conform to the widely varying ear canal diameters from about 6 mm to about 13 mm. For neonates and small pediatrics, where the ear canal diameter various from about 4 mm in diameter to about 7 mm in diameter, smaller and shorter ITE devices are used. Typically, sensors for measuring blood oxygen are positioned proximate to ear canal tissue that is perfused with arterial blood supplied by branches of the External as well as the Internal Carotid Arteries, thus serving as a well perfused physiological site even if the body is experiencing peripheral shutdown due to shock or other conditions. Such sensors include an energy emitting means (e.g., an LED, an IR source . . . ) and an energy detecting means that detects energy transmission through the vascular tissue. In another example, a temperature sensor (e.g., a thermistor) is also positioned proximate to vascular tissue. In yet another example, sensors for sensing audio signals (e.g., a microphone) indicative of pulse pressure sounds, and/or respirations are suitably positioned in relatively quite regions of the ear canal to mitigate sensing extraneous audio signals (noise).
The inflatable balloon 6 is also used to facilitate non-invasively measuring blood pressure. For a non-invasive blood pressure measurement, the inflatable balloon 6 is inflated until it occludes blood flow in a portion of the ear proximate a blood pressure sensor(s) (e.g., a pressure transducer) operatively connected to the inflatable balloon 6. The pressure in the inflatable balloon 6 is then suitably released to deflate the inflatable balloon 6. A systolic and a diastolic blood pressure are obtained during inflation and/or deflation using an auscultatory approach (e.g., via a microphone operatively connected to the balloon 6) and/or an oscillometric approach (e.g., via optical sensing components attached to the balloon).
A continuous non-invasive blood pressure is measured by obtaining an initial blood pressure measure as describe above and then re-inflating the balloon 6 to a mean pressure. A servo mechanism periodically adjusts balloon pressure to locate a maximum pulse waveform amplitude indicative of mean blood pressure. As long as the derived mean pressure is relatively close to the initial pressure and/or the pulse waveform amplitudes are relatively close, the derived continuous systolic, diastolic, and mean blood pressure are calculated with high accuracy.
The structure 4 includes one or more passageways (as illustrated in FIGS. 2-4 infra) that extend through the structure 4. Such passageways house sensor data, power, and control wires, provide a hermetically sealed channel for inflating/deflating the balloon 6, and/or allow pressure inside the ear to equalize with the environment during balloon inflation/deflation. FIG. 2 depicts an aspect in which the structure 4 includes a channel 10 for both housing sensor wiring and inflating/deflating the balloon 6. The channel 10 isolates the wires from the inner ear environment, mitigating contamination of both the ear and the sensor wiring and provides a pressurized air conduit to the balloon 6. FIG. 3 depicts an aspect in which the structure 4 includes separate channels for sensor wiring and inflating/deflating the balloon 6; one or more first channels 12 house sensor wiring and a second channel 14 provides the pressurized air conduit for inflating/deflating the balloon 6. FIG. 4 depicts an aspect in which an optional channel 16 provides an ear pressure stabilizing mechanism that allows ear pressure to equalize with the environment during balloon inflation and/or deflation. The channel 16 mitigates pressure build-up in the ear during balloon inflation and/or deflation and potential pain therefrom. The examples in FIG. 2-4 depict the structure 4 and the passageways 10-16 with circular shaped cross-sections. These particular shapes are not limitative and are provided for explanatory purposes. It is to be understood that the structure 4 and/or the passageways 10-16 can be essentially any shape (e.g., oval, rectangular, irregular . . . ) conducive to the ear canal.
FIG. 5 illustrates the ITE apparatus 2 inserted into an ear canal. The structure 4 is inserted such that the end portion with the balloon 6 residing in the ear canal is in a bony region of the ear. The balloon 6 is inflated to position the sensors 8 proximate to inner ear tissue to sense signals indicative of physiological states, including blood pressure, temperature, pulse, respiration, and blood oxygen, for example.
FIG. 6 illustrates the ITE apparatus 2 with an optional sheath 9 placed over the structure 4 and balloon 6 to protect the ear and the structure/balloon/sensor assembly from contamination. In one aspect, the sheath can be semi-permeable to allow air flow, but prevent fluid from moving from one side of the sheath to the other side. In another aspect, the sheath prevents substantially all matter from moving from one side of the sheath to the other side. The structure/balloon/sensor assembly can be disposable, washable, and/or sterilizable.
The structure 4 is shown supported in the ear by a (BTE) ear piece 18. The structure 4 can be operatively attached to the ear piece 18. Such attachment can be through a fastening means including a threaded connector, a snap, a set screw, an adhesive, a rivet, etc. FIG. 6 shows an exemplary connection region 20 between the structure 4 and the optional ear piece 18. A protective sheath 9 may be used to mitigate contamination of the physiological sensors if desired. In another aspect, the structure 4 and the ear piece 18 can be formed as a single unit.
FIG. 7 shows the BTE device 18 connected to the ITE device 2. The ITE device 2 includes a battery 21 which powers both devices. With this embodiment, the ITE device 2 and battery 21 are low cost and disposable.
FIGS. 5-7 above illustrate the optional ear piece 18 as a behind-the-ear supporting device. In a preferred embodiment, the ITE apparatus is connected to a behind-the-ear (BTE) device (18) by means of a semi-rigid connector tube that is formed to fit over and/or around the ear to prevent over insertion and to hold in position the ITE device with optimised orientation and positioning. It is to be understood that other types of supporting devices are contemplated. For example, the structure 4 can be mounted to supporting devices that attach to a region of the head, neck, shoulders, etc.
The BTE device 18 can house various electronics that receive physiological signals from the sensors 8 (e.g., via sensor wire extending through the passageways 10 and 12 briefly described above) and transmit the physiological signals to another transceiver (not shown) worn by the subject (e.g., a transceiver worn around the neck or waist) or to a remote device (not shown) such as a monitoring device, a database, a computer, and a graphical display. The BTE device 18 can optionally include a processor (not shown), memory (not shown), and a battery (not shown). The processor is used to control the sensors and electronics, process raw data, and read data from the sensors; the memory is used to store data and/or configuration; and the battery powers the processor, active sensors, and the transceiver.
In the embodiment of FIGS. 8-11, the one or more sensors 8 are located on a soft, pliable tip 22 (rather than directly on the inflatable balloon 6, or on the ITE device tip on a side opposite the inflatable balloon 6) that is operatively connected to the end of the structure 4 inserted into the ear. The balloon 6 is shown in FIG. 8, but has been removed from the FIGS. 9-11 for clarity of illustration. Upon inserting the structure 4 in the ear, the sensors 8 are still positioned by inflating the balloon 6; however, inflating the balloon 6 expands sensor carrying leaves 24 of the tip 22, which positions the sensors 8 proximate to inner ear tissue.
FIG. 12-14 depict the tip 22 as an expandable mushroom shaped element. In this embodiment, inflating the balloon 6 from the insertion level of FIG. 13 expands the soft, pliable tip 22, which positions the sensors 8 proximate to inner ear tissue (See FIG. 14). The tip 22 and/or balloon 6 also serve as an optical reflector, helping to reflect light from a light emitter through the tissue, from the bone, through the tissue, reflectively and transmissively, to the reflector, from the reflector back through the tissue and so forth, until it finally reaches the light detector. The back side of the tip 22 is opaque which blocks unwanted ambient light coming from within the ear canal. The tip (22) and/or the balloon (6) also serves as buffer between external ambient airflow and thermistor (8) that is measuring a surrogate of core body temperature. Flex-circuit connectors 26 each extend through the structure 4, bend around the balloon 6, and flexibly interconnect with an associated sensor 8.
The invention has been described with reference to the preferred embodiments. Modifications and alterations may occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be constructed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Sizing and positioning technology for an in-the-ear multi-measurement sensor to enable NIBP calculation


The invention concerns a gel covering of a patient interface. This gel covering has a mask connection area by which its side that faces away from the patient is joined with a mask body. The patient interface can be designed, for example, as a respiratory mask. On its side that faces the patient's face, the respiratory mask has thin, inwardly formed, peripheral contact lips. The respiratory mask has accessories that allow it to be fastened on the patient's head as well as a hose connection for supplying air. At least one region formed from a filler is placed in or on the walls of the gel covering. The method is used to produce the gel covering of the invention.

1. Field of the Invention
The present invention relates to a method for producing a patient interface that contains a gel filling.
2. Background of the Invention
A prior-art gel rim for a ventilator mask, as described in EP 0 799 076 B1, is made of a polyurethane (PU) gel, which is enclosed in a protective PU foil. An additional silicone covering is positioned between the patient's face and the PU gel body. The wall thicknesses of the PU foil and the silicone covering are held essentially constant. The hardness of the gel filling here is in the range below 10 Shore 00.
The material properties and hardness properties are not equally well suited for all users. Polyurethanes (PU) are formed by a condensation and adduction reaction between isocyanates and polyols. Numerous additives are used in the production of PU. Polyurethanes that are not completely cured may contain residual monomers, for example, isocyanates. Exposure to isocyanates and additives can lead both to allergic and irritative contact eczemas. This causes some patients to reject the PU materials.
Therefore, the objective of the present invention is to improve the comfort of wearing a patient interface and thus to improve patient compliance. A further objective of the invention is a cost-effective method for producing the patient interface.
The stated objective is basically achieved with the characterizing features of Claim 1, wherein the gel covering has a cavity that is filled with a gel of a certain consistency and elasticity.
A further objective of the invention is to design a patient interface of the aforementioned type in such a way that wearing comfort is improved and cost-effective production is achieved.
This objective is basically achieved by the characterizing features of the associated dependent claims.
The gel filling can have a wide variety of characteristics. Possible fillings range from gel materials, such as polyurethane gel or silicone gel and the natural gel agarose, to foams, gas mixtures and liquids, such as saline solution, which is widely used in medicine. Ultimately, it may also be the same material of which the gel covering is made, especially when it is foamed. Due to the integrated design of the invention, the thickness of the walls of the gel covering can be adapted very precisely to specifications in order to lend greater or lesser stiffness to some sections of the gel covering, exactly as needed.
The invention is suitable for every patient interface that rests against the patient's body. The invention can thus be used especially in the following types of patient interfaces: nasal, oral, and full-face masks, in nasal pillows or nasal prongs, in emergency, home, and hospital ventilation, CPAP, APAP, and bilevel ventilation, and in medical orthoses and prostheses and support devices.
To produce the patient interface of the invention, it is proposed that the gel covering be produced with at least one cavity by shaping methods from an elastic plastic, preferably a silicone, and that this cavity then be filled with the given gel. The cavity preferably should be filled through an opening provided for this purpose, which preferably is not situated in areas of the gel covering that come into contact with the skin.
It is especially preferred that the cavity be filled by injection of the filler material, and the covering is preferably pierced in its relatively thicker areas. After the filling operation, especially when the cavity is filled with liquid or gaseous fillers, the one or more openings are tightly sealed, for example, with a stopper, by welding or by adhesive bonding. Especially gaseous fillers can be placed under pressure during this operation, so that the pressure level can affect and determine the properties of the gel body.
In an alternative method of production, a covering blank is first sealed by a stopper, and a permanent connection between the covering blank and the stopper is then produced by the use of joining means, with the sealed covering being produced from a uniform material, preferably silicone.
In an alternative method of production, the geometry of the covering blank is predetermined in the production process by at least one metal core, and after the covering blank has been produced, the metal core is removed through an opening in the covering blank, where the length of the opening is less than half the circumference of the covering blank.
In addition, it is proposed that a covering blank be produced which is open in the area that defines the place of contact between the body of the mask and the patient interface. In the next step, the covering blank can be adhesively bonded onto the interface of the patient interface. In this connection, the patient interface can consist of a hard plastic (preferably PC, PP, or PA), silicone, or a hard plastic (preferably PC or PA) with an integrally fabricated silicone border (double-shot molding). This solution offers economic advantages, since only one joining operation is carried out.
Furthermore, it is proposed that a covering blank be produced which is peripherally open. A sealed gel body is inserted into the covering blank and then sealed by adhesive bonding or vulcanizing.
In accordance with the invention, it is also proposed that a covering blank be produced with several openings. All of the opening but one are then sealed. The covering is filled with gel through the remaining opening, which is then sealed by a stopper.
The region of the gel-filled covering that constitutes the contact contour to the patient is preferably thinner than 5 mm in cross section, especially preferably thinner than 3 mm, and most preferably thinner than 2 mm. In this way, a relatively hard gel feels like a soft gel to the patient. At the same time, the gel-filled covering is very light due to the thinness of the walls.
Optionally, a second skin is placed over the gel-filled covering and is thus positioned between the gel-filled covering and the patient when the patient interface is being used. The second skin can be undetachably joined with the gel body (formed as an integral part or adhesively bonded). Alternatively, the second skin can be mounted as a separate member on the gel body or on the patient interface.
The wall of the filled covering and/or the wall of the second skin preferably has a thickness, at least in some areas, of about 0.5 mm and, alternatively, even only 0.3 mm. In some sections, the thickness is up to 1 mm.
The gel body is secured on the patient interface by a frame, for example, by means of a clip mechanism.
Alternatively, the gel body is adhesively bonded onto the patient interface. The open gel body is preferably bonded directly onto a hard plastic part (PC) of the patient interface. Alternatively, the patient interface is fabricated by double shot technology and has a silicone component in the area of the interface with the gel body. The gel body is joined with the patient interface in this area by direct joining of the two silicone parts.
It should be noted that the scope of the present invention is not limited solely to the preferred embodiments that have been presented, and more extensive combinations and variants of the present invention can be derived from the independent and dependent claims by an individual with average skill in the art without his having to leave the scope of the present invention.
FIG. 1 shows a patient interface in the form of a nasal mask, whose mask body 1 is made of a relatively strong material and which has a gel-filled covering 3. This covering 3 is the part of the mask that rests on a patient's face (not shown) and provides the necessary seal. The mask body 1 is connected by an angled connector 2 to a sleeve 4, which is rotatably supported and serves to connect the mask to a respiratory gas hose (not shown). To guarantee secure positioning of the respiratory mask on a patient's head, a forehead support 5 is used, which has a shaft 35 that is inserted in a mount 36 of the mask body 1. The connector 2 and the mask body 1 are connected by a ball-and-socket joint 18. The ball-and-socket joint 18 is supported by a retaining ring 31. A forehead pad 13 is fastened on a mount 12 of the forehead support in a way that allows it to slide. The forehead pad 13 provides additional support for the mask on the forehead of the patient. The mask is fastened on the patient's head with straps (not shown).
On its contact side intended for contact with the patient's face, the gel covering 3 ends in a contact lip 7 that becomes thinner and thinner and provides the gel covering 3 with a soft and flexible contact zone all around its edge. The walls of the gel covering 3 are terminated on the patient interface side with a connecting member 6, which is realized either as a single piece with the gel covering 3 and consists of the same material as the gel covering 3 or as a part that is to be attached by an adhesive or welded joint.
The connecting member 6 is mechanically joined with a base part (not shown) of the mask by means of catching parts, or, alternatively, it can be undetachably joined with the base part of the mask by adhesive bonding or welding. The cavity 9 is bounded by the outer skin 8.
In accordance with the invention, the thickness or depth of the filler 15 can also be essentially constant along the cross section of the gel covering 3.
To fill the cavity 9 with a filler 15, the gel covering 3 has at least one opening, which is not shown in FIG. 1. This opening can be positioned in any desired place in the wall of the gel covering 3 except in the vicinity of the outer surfaces of the contact lips 7 and their surrounding area to prevent it from having a disturbing effect on the facial skin that will be contacted there. The filling hole is preferably sealed by adhesive bonding, welding or plugging with a stopper.
By using a thin filling of the cavity 9, for example, a soft buffer zone is realized. The buffer zone 16 is provided with a supporting function if the cavity 9 is filled with relatively inflexible material, for example, with gel with a hardness above 15 Shore 00. The flexible buffer zone 16 can also be realized in such a way that the filling has two different elastic properties at least in certain areas.
FIG. 2 is a perspective view of a gel covering 3, which has contact lips 7 all around its edge, which are designed to be formed inwardly into the gel covering 3. The wall 6 of the gel covering 3 serves to connect it with the mask body (not shown here) by means of mechanically locking elements, and it contains at least one cavity 9 with a filler 26, which is not shown in the drawing.
FIGS. 3 and 4 show further perspective views of the mask part according to FIG. 2. FIG. 3 reveals openings 10 located in the area of the lower part of the mask. The cavity 9 is filled with the gel through these holes. In one embodiment, the openings 10 are realized as hollows in the outer skin 8, which are sealed with stoppers 11 after the filling operation. In another embodiment, the openings 10 are realized as thickened regions of the outer skin, which are pierced with an injection needle to fill the cavity 9 and which seal themselves due to the elasticity of the material when the needle is pulled out. Ribs 14 are formed in the connecting member 6, which serve a position coding function and determine the orientation. In addition, the ribs allow a pneumatic passage from the interior space of the mask to the pressure gage socket (not shown) of the mask body.
FIG. 4 illustrates especially the use of stoppers 11, which are inserted in the openings 10 of the gel covering 3 after the cavity has been filled with the gel. The fabrication principle will be explained in greater detail later. The openings are preferably formed in the area of the connecting member 6, since the material thickness is greater there. A greater material thickness of the outer skin 8 is to be preferred both for the injection and for the subsequent adhesive bonding of the stopper 11 in the opening 10. The material thickness of the outer skin 8 in the area of the opening 10 is preferably greater than 1 mm in cross section and especially preferably greater than 2 mm in cross section. The opening 10 in the upper right section of the drawing is formed as part of the connecting member 6. Accordingly, the corresponding stopper 11 has the profile of the connecting member 6. The cross section of the stopper 11 reveals a peripheral undercut, which receives a corresponding groove in the mask body. The connecting member 6 has a slightly elevated and beveled insertion aid 17, which helps to achieve simple mounting of the gel rim on the mask body.
FIGS. 5 to 8 show cross sections through cavities filled with filler 15. In FIG. 5, the openings 10 are sealed with stoppers 11, and the cavity 9 is filled with gas. The drawing shows that the material thickness in the area of the connecting member 6 is at least twice as great in some sections as the material thickness in the area of the outer skin 8. In FIGS. 6 and 8, the cavity is homogeneously filled with a filler 15. FIG. 7 shows the openings 10 without stoppers and the cavities 9 without a filling. FIG. 8 additionally shows that the cavity filled with filler 15 can be shaped in various ways. In addition, in cross section, the cavity filled with filler 15 shows its thinnest point 19 in the area of contact with the patient.
The filler 15 in accordance with the invention makes it possible, within a very large range of shaping possibilities, to provide the gel covering 3 with predeterminable increased stability exactly in those areas in which it is needed, while other areas of the gel covering 3 are left with a thin wall thickness and/or a very soft material consistency.
The filling opening repeatedly described above can be designed as an opening in the conventional sense, which is resealed after the filler 15 has been applied. In particular, however, it is also possible to introduce the filler 15 in a flowable consistency by injection into the cavity 9. If this injection of the filler is carried out in a thick-walled region in a covering 8, 11 of the cavity, then, after the injection device has been withdrawn, the injection channel automatically seals itself due to the elastic properties of the material. This greatly facilitates the manufacturing process.
In another embodiment, different material thicknesses of the walls 8, 11 of the gel covering 3 can be chosen, so that, on the one hand, the thickness guarantees the necessary stiffness and, on the other hand, guarantees contact with the skin that is as soft and as tightly sealing as possible.
Especially in the area of the walls of the gel covering 3 that rest against the face, the wall has a smaller material thickness than the areas of the walls of the gel covering 3 that do not rest on any parts of the face 6.
The material thicknesses are preferably low in the area of the walls of the gel covering 3 that rest on the bridge of the nose. It is especially preferred that the material thickness of the wall in the area that rests on the bridge of the nose is less than in those areas of the wall of the gel covering 3 that rest on other parts of the face. This results in an optimal sealing function with minimal application of pressure in the area of the sensitive bridge of the nose.
FIG. 9 illustrates connections between the gel body 26 and a connecting member of the patient interface. The connecting member can consist of polycarbonate. The joint can be realized by a positive-locking connection according to the drawing on the left in FIG. 9, while in the embodiment illustrated on the right, an adhesive bond can also be realized, even with the use of silicone.
FIGS. 10 and 11 show an embodiment of the gel covering 3 of the invention. In this case, the gel covering 3 is joined with the patient interface (mask body) by means of locking mechanical elements in a mask connection area. The mechanical locking element is designed here as part of the outer skin 8 of the gel body, for example, by the double-shot process, and it has a latch that encloses an undercut of the patient interface. In the area of the joint 27 between the gel body 26 and the patient interface, there is a sealing contour (not shown).
FIG. 11 shows that the outer skin 8 is adhesively bonded with the gel body. The outer skin is preferably formed as a thin silicone lip, which overlaps the contact zone of the gel body with the skin. The adhesive joint 20 is located in the area of the connecting member 6. In addition, a locking mechanism that detachably connects the gel body 26 with the body of the patient interface can be realized in the area of the connecting member 6.
FIG. 12 shows a cross section through the joint 27 between the gel body 26 and the connecting member of the patient interface 23. The connecting member of the patient interface 23 can consist of polycarbonate (PC) or PA and is preferably hard. The connection is made here with a snap connection, which can be realized peripherally or only in segments. In the case of nasal masks and full-face masks, a segmented snap connection in the area of the corners of the triangular mask body is preferably contemplated. A recess 29 in the area of the connecting member of the patient interface 23 serves to receive the corresponding snap hook 30. The snap hook frame 31 is injection-molded or adhesively bonded as a hard part peripherally or in segments onto the mask rim 3, 7, 8, 24, 25, 32 (silicone/PU). A sealing element that has at least one sealing contour 33 is located in the joint 27. The sealing element runs peripherally along the joint 27 and preferably provides a sealing effect in the radial direction.
FIG. 13 shows five variants of possible means of connection. The upper three variants in the figure have positive-locking connections between the silicone and the rim of the mask. The fourth embodiment shows adhesive bonding without positive locking. The bonding gap is at least partially filled with adhesive in this case. The fifth embodiment is again a positive-locking connection. Even in the positive-locking connections, additional connection by adhesive bonding is also possible in order to increase the strength of the connection. The strength of the connection can be increased still further if the frame element and the gel rim are also adhesively bonded.
The gel rim and the gel are produced in a mold 34 of an injection molding machine 40; as shown in FIG. 14. To this end, the outer skin 8 (A) (e.g., silicone or TPE) is first injected and becomes deposited on the mold to form the outer skin. The gel (B) is then injected in the same or a second injection unit 41 and fills the entire interior space. It is also conceivable for the gel to first be produced from its two or more components at the time of the injection. For this purpose, at least one component is contained in a reservoir 41. This component is first metered in during or just before the injection of the gel fraction (B). If necessary, the first component is injected again to seal the injection point. This component is injected by the first injection unit or by a third injection unit.
The gel pad according to FIG. 14 is produced with an injection molding unit. To this end, the injection unit is filled in one shot with the first and the second component or the first component again (monosandwich).
It is also possible to inject a harder material as a third or additional component in order, if necessary, to realize a functional element or additional functional elements of the gel rim.
The gel pad according to FIG. 15 is produced with an injection molding unit 41. In this case, the covering blank is transported from a first mold 43 to a second mold 44, where the filling with gel substance is carried out. In this operation, a part of the mold or the whole mold is transferred, together with the article so far produced, from one machine to the other. It is also possible to move only the article between the machines.
However, as shown in FIG. 16, the filling can also be carried out with two, three or more injection units in one machine 40. The units are controlled by the machine and possibly by an additional transfer plate 45. the transfer plate switches from one component (a) to the next (B).
It is also possible, as shown in FIG. 17, to carry out the production process with the use of a machine 40 with an integrated transfer plate 45. In this case, feeding from the various units 41 is controlled in the machine.
The injection operation can be optimized by a pressure buildup with an auxiliary medium between the first and second component. To this end, more material of the first component than is needed is injected into the mold. In an intermediate step, excess material is then forced back out of the mold by the auxiliary medium. Suitable auxiliary media for this purpose are gases as well as liquids.
The gel rim is produced quasi in one operation, in which the so-called monosandwich process is used. In the monosandwich process, two melts are first stratified one after the other in a common worm cylinder, such that the second melt is plasticated by a secondary extruder into the worm cylinder of the main machine. The injection operation is then carried out with only a single stroke, as in conventional injection molding. The sandwich structures result from the flow properties of the axially stratified melts in the worm cylinder.
The material that is injected first is deposited as a skin on the mold wall, and the material which follows forms the core. Thus, with respect to the gel rim, first the silicone skin (outer skin) is formed and then the silicone gel (core layer).
The prefabricated gel rim is manually or mechanically mounted on the frame geometry (double shot frame with a bubble and coupling for the central element), and the joint is adhesively bonded and/or vulcanized.
In this regard, it is contemplated that a projection of silicone 3.0-15.0 mm long is formed beyond the frame (on the patient side), which as a male or female joining unit fits the female or male matching part of the gel mask rim.
Before, during or after the mounting of the gel mask rim, this joint is filled either with a silicone adhesive or with an LSR (liquid silicone rubber). The silicone adhesive is cured under room conditions, while the LSR adhesive joint would be vulcanized under elevated pressure and temperature by means of an additional compression mold.
The nasal pillow mask is a special form of a patient interface and serves to convey gas to the patient's nose. As FIG. 18 shows, the pillows are produced from a soft material, such as silicone, which can be adapted to the shape of the nose, thereby providing a good seal and avoiding leaks. The shape of the pillows is oval or kidney-shaped. The two pillows form a unit. They can provide a seal directly on the edge of the nose or can be slightly inserted into the nose. Gel pads 26 embedded in the nasal pillows 25 can also prevent pressure points that might otherwise develop here. Small accordion folds 36 in the joining area of the nasal pillows allow better positioning of the nasal pillows 25 on the patient's nose.
The nasal pillows 25 are joined to the body 22 of the mask by a holding area made of a harder material. This can be joined with the nasal pillows by the double shot process and is held on the body 22 by a locking mechanism. Another variant provides direct joining of the soft nasal pillows 25 to the body 22. In this connection, the nasal pillow 25 is folded over the body 22 and held in the holding area 24 of the body 22. This holding area 24 can be formed in such a way that it forms the end support of the ball-and-socket joint 10.
In another embodiment, the ball of the ball-and-socket joint 10 can be inserted from the outside into the holding area 23 of the body 22 by the application of a small amount of force. To this end, it is provided that the ball or the socket is made of a stable plastic material, which readily elastically yields and deforms under the pressure of insertion of the ball but then returns to its original shape and holds the ball.
FIG. 19 shows a side view of and a longitudinal section through a nasal pillow. To bound the cavity 9 for receiving the gel filling, the component of the extension 45 of the nasal pillow cushion 38 that extends to the left is produced, and after it has been released from the mold, this extension 45 is folded over towards the inside. This bounds the inside of the cavity, and the gel filling is shielded from the interior space. The extension 45 that has been folded over can be adhesively bonded with the other wall material. A bending point, which in the present case takes the form of a notch, is provided in the area of the extension 45. This makes it easier to fold over the extension and provides the length of the extension 45 to be folded over. In its folded state, the extension reaches as far as the stop 47.
FIG. 20 shows a side view of and a longitudinal section through a nasal pillow with the extension folded over. The cavity 9 for receiving the gel filling is bounded here on the gas-carrying inside by the extension 45 and on the outside by the outer skin 8. To this end, the extension 45 was folded over as far as the stop 47 and adhesively bonded. It is seen that the wall thickness of the outer skin 8 is lesser in the area of the nasal pillow cushion 38 that holds the gel filling than in the area that lies below the stop 47. The lesser wall thickness supports the pressure-relieving and sealing function of the gel filling.
FIG. 21 shows a side view of and a longitudinal section through a nasal pillow that consists of two parts. The body 25 of the nasal pillow and the nasal pillow cushion 38 are produced separately, and the nasal pillow cushion 38 is filled with the gel before it is joined with the body 25 by adhesive bonding.
Naturally, all of the geometries are conceivable/realizable in mirror-image arrangement (as an example, the groove in the silicone shoulder of the frame and the plug in the gel mask rim).
It is also possible for the geometry to be such that, e.g., the female end is preformed in such a way that it does not deform into its final position until it is mounted on the opposing end (male part). This effect would promote secure support and satisfactory adhesive bonding.
The embedding of gel fillings is accomplished by filling sections of the nasal pillow. This makes it possible to realize better wearing comfort and/or better strength. The material of the nasal pillows is usually silicone. The embedded gel is a silicone gel, which is realized with a hardness in the range of less than 20 Shore 00, preferably with a hardness in the range of 10-20 Shore 00, and more preferably with a hardness on the order of 15 Shore 00. Surprisingly, it was found that gel with a Shore hardness on the order of 15 Shore 00 is especially well suited for sealing the patient interface airtight at elevated ventilation pressure in the contact zone with the underside of the nares in a way that provides sufficient support and at the same time is comfortable for the patient.
The filling can be carried out in a variety of ways. In a first variant, the nasal pillows can be realized as a single piece, and the gel filling 26 can be injected through a membrane 39 in the covering that is located on the side of the nasal pillows that faces away from the patient. Each nasal pillow has two membrane openings 39, which serve the purpose of filling and simultaneous venting during filling. This is illustrated in FIG. 22. In another variant (FIG. 23), the body 25 of the nasal pillow and the two nasal pillow cushions 38 are produced separately, and the nasal pillow cushions 38 are filled with the gel 26 before it is joined with the body 25 by adhesive bonding.
The nasal pillow cushions 38 and the body 25 of the nasal pillow are secured against torsion by a tongue-and-groove joint to prevent incorrect assembly of the nasal pillows. The wall shape and thickness of the pockets to be filled with gel can be variable. The gel filling is preferably located in a region of the nasal pillows that rests against the underside of the nares and also extends at least partially into the region of the nasal pillows, which are inserted in the nose. In addition, the silicone covering is 10-50% thinner in the area of the gel fillings than the rest of the wall and preferably 20-40% thinner in order to guarantee better adaptation to the patient.
Other variants of embodiments with support on the bridge of the nose or on the side of the nose allow the patient a free field of vision. For one thing, the nose support can be accomplished by means of small, commercially available spectacle bridges or by a relatively large-area gel pad, which is mounted on the nose support and preferably is suitable for patients who are very sensitive to pressure. The mount of the nose bridge support is connected by a snap-in mechanism with the guide part of the forehead support, so that optimum adjustment is guaranteed. The variants of embodiments shown in FIGS. 22 and 23 can be realized both as a nose support without a forehead support and as a nose support with a forehead support.
By varying the silicone Shore hardness, e.g., the attachment region in the gel variant, more precisely, the double shot bubble and the actual connection shoulder, could be harder than in the standard silicone variant injected in one piece. This would not be noticed or would hardly be noticed (not disturbing) in a comparison of gel with silicone and would be helpful during mounting.
It is also possible to produce the gel forehead pad covering by a type of gas injection technique. In other words, the forehead plate is inserted in a production mold, and silicone is injected through a borehole within the forehead plate (plastic plate that serves as a locking element of the forehead pad) in such a way that the silicone is deposited only on the outer covering of the bell-shaped forehead pad (material is deposited as a skin on the inside of the mold wall) (wall thicknesses of 0.5-1.0 mm). This technique allows fabrication of the covering without a mold core (steel core that forms the inner region of the covering in a conventional mold).

Gel filling for patient interface and method for producing patient interface with a gel filling

LOEWENSTEIN MEDICAL TECHNOLOGY GMBH + CO. KG