Abstract: An air filtration system includes a light weight container which stores a quantity of water for filtering contaminants from inhaled air. A coupling assembly is used to connect the container to a flexible hose for delivery of the filtered air to the dust mask worn by the user. The coupling assembly allows a user to interchange one light weight container with another in a quick and convenient manner if one container becomes saturated with contaminants. A user simply pulls downward on the slidable jacket to release the industrial plug and allowing the attachment of another container to the hose via the coupling assembly.

Abstract: Electret filter media comprising a nonwoven web of thermoplastic nonconductive microfibers having trapped charge, said charge provided by (1) subjecting the nonwoven web to a corona treatment, followed by (2) impingement of jets of water or a stream of water droplets on the web at a pressure sufficient to provide the web with filtration enhancing electret charge and (3) drying the web. This electret filter media may be used in a respiratory mask to provide extraordinarily good filtration properties.

Abstract: An electret filter media includes an additive or mixtures thereof that enhance the charge stability of the media. The filter media achieves acceptable alpha values for a range of filtration challenges without significant decay in alpha values over time. Preferred charge additives include fatty acid amides, oleophobic fluorochemical surfactants, and mixtures thereof.

Abstract: A gas mask has a facepiece defining an interior chamber and an opening spanning a front portion of facepiece. An optical panel visor is mounted in the opening in the front portion of the facepiece. A hinge joins opposite sides of the visor along a vertical line for relative rotational movement of the opposite sides of the optical panel and the facepiece with respect to each other.

Abstract: A respiratory mask assembly for filtering airborne biological and/or chemical agents from air for breathing, comprises an outer hood adapted to seal with and encompass at least the head and neck of a wearer from ambient atmosphere, at least one transparent lens attached to the outer hood for providing visual sight to the wearer, at least one filter assembly attached to the outer hood, the filter assembly adapted for filtering airborne biological and/or chemical agents from air passing therethrough, an airflow regulator located in the outer hood, the airflow regulator including an outlet adapted for expelling exhaled air to ambient, and an inlet adapted for drawing air thereinto, and air conveying means located in the outer hood for conveying air filtered through the filter assembly from ambient to the inside surface of the transparent lens for drawing into the airflow regulator inlet.

Abstract: The invention features methods and apparatus for the treatment of asthma patients. A controlled supply of breathable air delivered to a patient interface or mask (4) is controlled for patient comfort to maintain a steady pressure level in a range 2 to 4 cm H2O to accommodate patient respiration. The breathable air is cleaned by a high efficiency particulate arresting filter (10) to remove allergens from the air supply. The apparatus may be programmed to automatically detect asthma-related symptoms such as an asthma attack by analyzing the respiratory flow of the patient. In response to the detection of such an attack, the apparatus may provide an audible warning or if configured with a treatment delivery module (14A, 14B), the device may administer a therapeutically effective dose of a drug or substance, for example, a broncho-dilator, to alleviate the patient's breathing difficulty. Preferred mask designs allow for proper CO2 washout to accommodate the low pressures supplied to the mask and prevent asphyxia.

Abstract: An improved structure of respirator filter comprised of a laminated layers of fireproof fabric, static fibers, active carbon fibers and non-woven filter cotton; interlaced with airflow guides in among the layers of the filter; a hole or multiple holes being respectively provided at the center or in the peripheral of another airflow guide so to create air conduction for increasing area and time for the gas to contact the filter for improved smoke and toxicity filtration effects.

Abstract: In a ventilation system, such as anaesthesia machines or ventilators for intensive care, provided with a hosed directed to patient, a breathable gas supplying tube, an exhaustion tube and an antibacterial/antiviral filtering device connected at one side to the hose and at the other side to the breathable gas supplying tube and to the exhaustion tube, the filtering device including a casing, provided with an inlet conduit connected to the breathable gas supplying tube, and an outlet conduit connected to the hose; the casing having at least two chambers having parallel axes, defined by at least a common wall, and in fluid connection one with the other.

Abstract: A respiratory protection apparatus has a face body, and a right side and a left side of a vertical centerline of the body are respectively provided with filtering devices each of which houses an electrical fan unit therein. Without narrowing the field of the front vision, without increasing the front side weight, and without deteriorating the work efficiency and comfortable fitting, the apparatus ensures the air flow rate of more than 120 liters per minute. Moreover, the electrical fan unit may be detachable from the face body, so that the face body is easily washed and parts are readily replaced with new ones.

Abstract: A dental mask which has two separate chambers, one for inhalation and the other for exhalation. The two separate chambers being separated by an elasticized strip across the philtrum area. The mask is designed to be disposable, yet also have the ability to accept, for increased protection, filter insertable pads which can be placed in the inner surface of the mask. An embodiment of the mask would allow the main frame to be reusable, by having means for snapping a disposable filter onto the frame.

Abstract: The present invention is a protective respiratory apparatus including a neck-sealable hood adapted to enclose the head of a wearer, the hood having an interior and exterior, two filters sealingly secured in symmetrical relation to the hood wherein air passing from the outside of the hood to the inside of the hood is filtered of contaminants, a half-mask cup inside the hood, the cup adapted to sealingly cover the nose and mouth of the wearer, the cup mechanically, but not fluidly coupled to the two filters, and at least one air intake valve in the cup wherein filtered air resident in the interior of the hood is drawn into the half-mask cup for respiration by the wearer.

Abstract: The present invention discloses a seamless pad-type filter which is characterized in that it comprises two co-extensive sides, a top side and a bottom side. The top and bottom sides are made of fluid filtration material. The two sides create an inner chamber therebetween and are surrounded and joined together by a seamless outer perimeter. The seamless outer perimeter providing a seamless folded continuity between the two sides of the pad-type filter in the form of a plurality of fold lines which, as connecting segments beginning and ending at the same point, define the seamless outer perimeter. The top side further comprising a plurality of positive and negative secondary creases formed around a plurality of positive and negative crease lines. The crease lines are inclined to the fold lines and form pleats.

Abstract: A method and apparatus for protecting humans against hazardous particulate agents such as biological or chemical agents. A special porous cloth contains activated carbon threads that is used as a quick escape mask to cover the mouth and/or nose of a person to protect the person from inhaling hazardous particulates. This simple cloth mask may be designed for short-term emergency respiratory protection and can be particularly convenient for use by people who are in relatively public, enclosed areas (such as in restaurants, bars, or hotel rooms) and who might need to evacuate those areas in a short period of time. The cloth may also be used in other applications, for example, as a tent liner, as a liner for military uniforms or diving suits, or as a water or air filtration device. In addition to protection from hazardous agents, the cloth may sometimes additionally filter out bad odors.

Abstract: The present invention provides filtration materials and face masks that include a spunbonded/meltblown/spunbonded (SMS) laminate.

Abstract: An oxygen mask filter system for preventing the transmission of a disease from a patient to medical personnel. The oxygen mask filter system includes a face mask having an interior surface and an exterior surface, a plurality of vent apertures, a disk member movably attached to the exterior surface of the face mask about the vent apertures, and a filter member attached to the interior surface of the face mask for filtering gases prior to expulsion from the interior of the face mask to the exterior through the vent apertures.

Abstract: An improved structure of respirator filter comprised of a laminated layers of fireproof fabric, static fibers, active carbon fibers and non-woven filter cotton; interlaced with airflow guides in among the layers of the filter; a hole or multiple holes being respectively provided at the center or in the peripheral of another airflow guide so to create air conduction for increasing area and time for the gas to contact the filter for improved smoke and toxicity filtration effects.

Abstract: Personal Air Filtering Device with a face mask comprised of nonporous material, the face mask held onto the user's head by standard elastic straps, the face mask having a flexible gasket about its perimeter to provide an airtight seal between the mask and the user's face, the face mask having a check valve that lets exhaled air out of the mask but does not let unfiltered air into the mask, a flexible tube that enters the face mask at one end and enters an air filtering assembly on the opposite end, said air filtering assembly enclosed in a housing, said housing having an air intake opening, and said air filtering assembly including an air moving device such as a fan or pump, a carbon filter cartridge, a particulate matter filter, a battery power supply, and an on-off switch. A preferred embodiment includes said flexible tube held onto the user's clothing by a neck clip.

Abstract: A device for removing airborne contaminants and inhaled biopathogens, particularly particulate or aerosol contaminants, from respired air that can be either stationary or incorporated into a garment or accessory worn upon the body. In a preferred embodiment, the device provides multiple levels of protection against inhalation of a dangerous airborne contaminant. In a preferred embodiment, a negative electrode of a portable power supply such as a battery is connected to voltage multiplier and modulation circuit and than to a discharge electrode having an electron emissive surface disposed near the wearer's airway such as, for example, on a chin guard disposed in front of the airway. The positive (counter) electrode is similarly disposed away from the airway such as, for example, near the forehead, but is electrically insulated from the wearer's body.

Abstract: An on-off valve mounted in a high pressurized gas container, which has a holding portion for holding a flow amount controlling member in a path formed in an upper stream side of the body of the valve, and in which a flow amount controlling member is movably held. In the flow amount controlling member, an orifice is formed. When the valve moves into an opening position, a high pressurized oxygen gas is flowed into a valve chamber by gas pressure, the flow amount controlling member moves and closes the path. At this time, the gas flow amount is restricted by the orifice, so that the pressurizing speed of the gas pressure at the down stream side of the orifice becomes slow and then heat generation due to the adiabatic compression is reduced.

Abstract: A filtering face mask that covers at least the nose and mouth of a wearer and that includes an exhalation valve. The exhalation valve opens in response to increased pressure when the wearer exhales to allow the exhaled air to be rapidly purged from the mask interior. An exhale filter element is placed in one of several locations in the exhale flow stream to remove contaminants from the exhaled air. The face mask is beneficial in that it provides comfort to the wearer by allowing warm, moist, high-CO2-content air to be rapidly evacuated from the mask interior through the valve and also protects the wearer from splash fluids and polluted air while at the same time protecting other persons or things from being exposed to contaminants in the exhale flow stream.

Abstract: The present invention relates to a fan-forced positive pressure breathing apparatus commonly known as a Powered Air Purifying Respirators (PAPR) system, and specifically concerns the connecting of the breathing components of such equipment. The invention is a method and apparatus for rapid engagement of PAPR breathing components (such as air supply lines and filter elements to a blower housing). The invention also provides for indicating and/or monitoring whether the relative components have been aligned and coupled in sealed engagement.

Abstract: A multilumen filter device has a housing with first and second filter chambers, each chamber in fluid communication with a separate distal and proximal fluid path. The filter device may be used to provide respiratory gases to and receive expiratory gases from a patient connected to a unilimb respiratory circuit. The filter device may also serve as a connector for respiratory circuit components, and have fasteners or blocking devices at either or both of its distal and proximal ends.

Abstract: A respiratory protection air-purifying device that minimizes the area required in front of the face, especially around the mouth area, by locating the heavier filter cartridge behind the head, resting on the lower neck and shoulders, connected by two filtered air tubes around the head and neck partially counter-balancing the valve chamber directly in front of the mouthpiece, forming a ring around the head with the mouthpiece in the mouth and the exhaust port in the bottom of the valve chamber. The valve chamber has the filtered air intake check type valves opposite each other horizontally, an exhaust check type valve down with short exhaust tube and an oval mouthpiece tube passing through the mouthpiece, into the mouth. The respirator is worn around the head and neck with the filter resting on the lower neck and shoulders, the mouthpiece inserted in the mouth.

Abstract: A nose airflow enhancer and filter for airborne solids and pathogens utilizing a flexible plastic spring material having an attachment system to connect the spring material to the nose in a U-shaped configuration, with the plastic material underlying the nostrils, the spring material having attached thereto a length of filter material which underlies and is in substantial contact with the nose, thereby permitting the filter material to remove airborne solids and pathogens during breathing of the user while airflow through the nose is enhanced.

Abstract: A stackable filter device for filtering an input to a source of suction comprises: a substantially hollow filter pad having first and second filter walls constructed of a filter material, the periphery of the first filter wall being sealingly engaged to the periphery of the second filter wall to form the filter pad, each of the filter walls having an aperture. The first and second filter walls each have an annular member fixedly contacted to the circumferential edge of the aperture. The annular members support the aperture, and are structured so as to integrally form connectors operable to removably connect the filter device to the source of suction or to an additional filter device on a first side of the filter device and to a sealing end cap or an additional filter device on a second side of the filter device. The filter device preferably includes a tubular stiffening member passing through the filter device. The stiffening member is rigidly attached at each end thereof to one of the annular members.

Abstract: A negative pressure respirator 20′ that has an integrally-disposed filter element 28 and that covers at least the nose and mouth of a wearer. The respirator 20′ includes an exhalation valve 22 and an impactor element 50 that covers the exhalation valve 22. The exhalation valve 22 has a diaphragm and an orifice and opens in response to increased pressure when the wearer exhales to allow exhaled air to be rapidly purged from the mask interior. The impactor element 50 is positioned in the exhale flow stream to remove particles and other contaminants from the exhaled air. The exhalation valve and impactor element have a ratio of Zn:Dj of less than about 5.

Abstract: An apparatus for supplying a breathing gas to a patient has a gas supply for generating a flow of breathable gas during an inspiration and an expiration phase of a patient breathing cycle. An inspiration line is provided having an inlet through which a flow of breathing gas from the supply can pass as well as an expiration line through which an expiration gas from the patient can flow. A flow controller is provided for selecting, during an inspiration phase, a first flow path for gas from the supply into the inlet and for selecting, during the expiration phase, a second flow path for gas from the supply in a direction across a venturi outlet of the expiration line, to enhance removal of expiration gas therefrom by venturi suction.

Abstract: A smoke mask includes a generally planar breathing filter sized to cover the nose and mouth of a user. The breathing filter may be either dry or moistened, and has a filter efficiency of at least about 95%, meaning that at least about 95% of charge neutralized particles having an approximate size of 0.3 micrometers are removed from air flowing at a rate in a range of about 81 liters per minute to about 89 liters per minute, with a total filter load of at least about 200 milligrams of the particles. A transparent eye shield, which may be either a plastic film or goggles, is attached to the breathing filter. Pressure sensitive adhesive is located on the peripheral edge of one surface of the mask structure for securing the mask to the face of the user.

Abstract: An improved multi-layer face mask has at least one adhesive strip applied between the inner face cover layer and the intermediate filter layer. The adhesive strip is defined so as to extend across the filter body and is bounded on each longitudinal side by longitudinally extending regions that are free of adhesive. The adhesive strip may be disposed along a pleat formed in the face mask body. For example, the adhesive strip may have a width so as to extend between parallel fold lines of a pleat.

Abstract: A disposable travel mask has a body and is held in position over the nose and mouth of a wearer. The body of the ask has a filter area for entrapping air-borne contaminates. The filter area has at least two layers, such as an inner layer adjacent the wearer's mouth and an outer layer. The outer layer entraps large contaminates such as dust and also traps at least a portion of the bacteria or other germs. The other layer entraps contaminates that have passed through the first layer. The travel mask may be assembled from commonly available materials. For example, an anti-allergen filter material may be sealed to a surgical mask or a laser mask. The travel mask may have a printed design or pattern to make the travel mask more aesthetically pleasing and to allow the travel mask to better blend into a travel environment.

Abstract: An electret is described that includes a surface modified polymeric article having surface fluorination produced by fluorinating the polymeric article.

Abstract: An improved respirator filter assembly includes an integral fit seal check mechanism easily controlled by the user. Upon release, the seal check mechanism permits free airflow through the filter assembly. The seal check mechanism includes an air passageway having a sealing rim and a blocking member which is selectively movable between engaged and disengaged positions relative to the sealing rim. A spring element is disposed to releasably maintain the blocking member in the disengaged position during filter assembly operation, wherein a user may actuate the blocking member against the bias of the spring element to move the blocking member into the engaged position to substantially prevent entry of air into the air passageway during seal checking.

Abstract: A filter material laid in folds in a plurality of folds, characterized in that the folds are provided with at least one bending portion having a bending resistance moment that is reduced in comparison with the remaining portions and a method and apparatus for producing same.

Abstract: An arrangement to provide a moisture barrier and bacteria barrier for various medical components that is connected to a measuring tube, arranged in the flow paths of a respirator is simple and inexpensive and exchangeable and does not cause a flow resistance in the flow paths of the respirator. A carrier carries at least two moisture barriers and bacteria barriers such that one barrier, given a carrier introduced in the respirator, is arranged exactly in front of each component.

Abstract: A catheter mount incorporates a filter pleated along its length in zig-zag fashion. Opposite edges of the filter are sealed between identical upper and lower parts of a housing between teeth extending along opposite sides.

Abstract: Respiratory devices having first and second lines of demarcation bisected by a fold. The devices are capable of being folded in a first substantially flat configuration for storage (e.g., in a pocket) and are capable of being unfolded in a second ready-to-wear configuration so that a portion of the device covering the nose and the mouth is off-the-face. Processes for making such devices include folding a preform over a bisecting axis and cutting the preform at desired angles and sealing the cuts together to form the mask.

Abstract: A protective structure for use in a surgical environment includes a face shield formed as a transparent tube to extend around the wearer's head and a cloth head covering extending above and around the face shield, with a viewing aperture being formed in the head covering to extend in front of the wearer's face, and with the head covering being attached to the face shield around the viewing aperture. A support structure extends from a rear portion of the face shield to a front portion thereof, forming an air channel through which air is moved by an internal fan between an air inlet aperture in the head covering at the rear of the support structure and an air outlet at the front of the support structure above the wearer's face.

Abstract: An air-impermeable hood having first and second substantially airtight seals adapted to encircle a portion of a wearer's body below the head, typically the neck. Continuously exhaled air from the wearer of the hood is channeled between the first and second seals pressurizing a space there between creating a continuously pressurized purge zone to the introduction of ambient air into the hood. When the pressure in the purge zone exceeds the resistance of the second seal, air taking the path of least resistance flows out of the second seal. The effect is that exhaled air from the wearer creates a pressurized barrier against ambient air yet also prevents the accumulation of excess carbon dioxide and moisture within the ocular area.

Abstract: The present invention is a protective spark cover for covering the exterior face of a filter for use with a respirator or the like. During metal welding, smelting and cutting operations and similar activities creating sparks, splatter and the like, exposed respirator filters may be perforated and made unusable. The present invention protective spark cover provides a removable cover to protect such filter elements from welding and spark damage and other similar mechanical damage. The invention is essentially a screen cover to protect the filter element and a frame to hold the screen in place over the filter.

Abstract: A bi/multi-directional air flow filter cartridge includes a filter pad and a filter pad base. The filter pad includes: outer filter walls made of a filter material suitable for filtering at least particulates, the walls being spaced apart to define an inner area therebetween, and to allow air to pass into the inner area from two or more directions; and a gas/vapor adsorber/absorber member, located within the inner area defined by the outer filter walls, the filter walls maintaining a spacing between inner surfaces of the walls and the gas/vapor adsorber/absorber member, wherein the gas/vapor adsorber/absorber member includes an adsorber/absorber upstream portion of its outer surface structured to, in response to a source of suction, receive air that has already been filtered by the filter walls, such that the air passes through at least a minimum length of the gas/vapor adsorber/absorber member and then out of an opening in the filter pad at a downstream portion of the gas/vapor adsorber/absorber member.

Abstract: The present invention provides a flexible respirator filter having substantially coextensive front and back portions of filter material which are sealed to each other along their periphery, forming a sealed edge. A flexible plastic frame is contained within the front and back portions to form a plenum between the front and back portions of filter material. The frame has a peripheral edge which remains adjacent to the sealed edge of the filter material along substantially the entire length of the sealed edge to provide sufficient rigidity to prevent crushing while at the same time providing sufficient flexibility to fit under other personal protective equipment. A connector for attaching the filter to the respirator mask is formed integrally with the frame such that it protrudes through the back portion of the filter material. A plurality of recesses are also formed integrally with the frame to facilitate grasping the filter without crushing or damaging it.

Abstract: An improved oral/nasal mask-hood is provided for protection of individuals in the event of fire or smoke exposure. When attached to a supplemental supply of oxygen the mask-hood also provides hypoxia protection to individuals exposed to decompression as in some aircraft incidents. The mask-hood employs a five stage filtering process for converting toxic atmospheric air to breathable fresh air. The hood covers the wearer's head, neck and shoulder area. A neck seal is provided inside the hood for preventing gases from locating within the hood and irritating the wearer's eyes. A transparent member is located on the hood adjacent the wearer's line of sight to provide visibility during the emergency. The hood-mask device, as assembled, is small enough to retrofit into the space provided for the present decompression mask alone.

Abstract: A filter mask is provided for use in environments of smoke and toxic gas which includes a filter element having a filling of shiftable bodies coated with a flowable, aloe vera extract having a gel-like viscosity and a retainer for holding the filter element over the mouth and nose of the wearer. The coating has a pH level which is alkaline which aids in the reduction of toxic gases such as hydrogen cyanide, hydrogen chloride and acrolein inhaled by the wearer. The filter element is preferably replacably mounted to the retainer, and may be provided as a bag-like flexible fabric container adapted to shift so as to conform to the face of the wearer. The filter element itself is adaptable to a variety of different uses for removing smoke particulates and toxic gases from air flowing therethrough.

Abstract: A method and apparatus in which a granular adsorbent, absorbent, chemisorptive, or catalytic material, particularly activated carbon is intermixed with (a) meltable polymer(s), and that the resulting mixture is heated under pressure and pressed into a molded piece (2). We propose to heat the mixture under pressure in a connecting part for a respirator or fan filter unit or in a connecting part (1) for an adapter for a respirator or fan filter unit, thereby positively and/or non-positively compacting it with said connecting part, and to make the connection between said connecting part (1) and said compacted mixture gastight.

Abstract: A device is disclosed for monitoring the respiration parameters of an artificial respiration system. The proposed device has a treatment device including a filter and/or heat-and moisture exchanger fitted in a respiration tube system and is based on evaluation by a monitoring unit of pressure and/or flow-rate values in the respiration system. Inside the respiration system, pressure sensors are provided upstream and downstream of a flow resistance in the treatment device and pressure sensors are provided upstream and downstream of another flow resistance suitable as a reference. The signals from the pressure sensors are fed to the monitoring unit which determines the respiration parameters from the pressure difference &Dgr;p3 above the flow resistance in the treatment device, the pressure difference &Dgr;p4 above the other flow resistance suitable as a reference within the respiration system, and from the time t.

Abstract: A vacuum system for medical tables, primarily comprises a universal arm, attached inhaler masks and a vacuum source. This equipment primarily places the inhaler masks at the sides of patient's mouth. Then, through the vacuum source, the mist surrounding the patient's mouth and the dirty air breathed out by the patient will be inhaled and clean air is released after filtering.

Abstract: The present invention provides a portable protective system for protecting a wearer, and for protecting the environment about the wearer. The protective system includes a face shield coupled with a head cradle for supporting the face shield on the wearer's head. The face shield and a wearer's face substantially define a breathing zone charged by a battery-powered blower carried on the head cradle. An bag-like inlet filter element encompasses the blower to provided filtered air to the breathing zone, and an outlet filter element is operably associated with the face shield.

Abstract: A respirator 10 includes a compressible filter element 12, a filter element retainer 14, and a face piece 16. The respirator is unique in that the filter element 12 compresses when installed in the retainer 14, allowing a friction fit to be maintained between the filter element 12 and retainer 14. The friction fit enables the filter element 12 to be readily replaced when its service life has expired.

Abstract: The present invention provides a portable protective system for protecting a wearer, and for protecting the environment about the wearer. The protective system includes a face shield coupled with a head cradle for supporting the face shield on the wearer's head. The face shield and a wearer's face substantially define a breathing zone charged by a battery-powered blower carried on the head cradle. An bag-like inlet filter element encompasses the blower to provided filtered air to the breathing zone, and an outlet filter element is operably associated with the face shield.

Abstract: A cold weather air warming apparatus for permitting a user to breathe air warmed by the body. The cold weather air warming apparatus includes a mouthpiece that has a mouth engaging portion, a coupling portion, and a lumen extending through opposite ends of the mouthpiece. A length of body tubing has opposite open first and second ends. The first end of the body tubing is coupled to the coupling portion of the mouthpiece. The length of body tubing is flexible and adapted for wrapping around a torso of a user, the open second end of the length of body tubing is in communication with the lumen of the mouthpiece.

Abstract: An introducer sheath includes a connector body having an inlet and an outlet; a flexible tube for intravenous use at the outlet, including a helical coiled spring having a plurality of coils, each coil spaced from an adjacent coil, and a thin cylindrical wall prepared from a protective coating composition completely surrounding the spring to define an inner and an outer wall surface, the cylindrical wall surrounding said spring having a substantially constant wall thickness throughout its length, the coating composition comprising a thermoplastic polymeric material dissolved in a solvent solution, the composition having a solids content ranging from about 4% to about 18%, and said solution comprising a solvent selected from the group consisting of tetrahydrofuran, dioxane, methyl ethyl ketone, dimethylformamide, cyclohexane, and mixtures thereof, formed on a helical coiled spring by dipping the latter therein and then drying at room temperature; and a valve assembly including a first elastic membrane having a