Abstract: A two-part coupling structure includes a male coupling part and a female coupling part which are mutually engageable to open fluid communication between a fluid-storage vessel and a conduit. The coupling parts are disengageable from one another to discontinue fluid communication between the vessel and the conduit, and also to close communication between ambient and each of the vessel and conduit. The retention volume of fluid which is trapped between the connected male and female coupling parts and which is exposed to or lost to ambient when the coupling parts are disconnected is very small. Because of particular structural features, the coupling parts will function reliably even with fluid having chunks or particulates of non-fluid material therein.

Abstract: A fuel-delivery control system is provided for use in a fuel tank. The fuel-delivery system includes a housing module formed to include a fuel-delivery channel and a check valve assembly positioned to lie in the fuel-delivery channel. The check valve assembly includes a support base formed to include a guide passageway, a mounting fixture inserted into the fuel-delivery channel and arranged to interconnect the housing module and the support base, a valve member, and a spring. The valve includes a guide stem extending into the guide passageway for movement therein and a closure member appended to the guide stem for movement with the guide stem between a channel-closing position engaging the housing module and a channel-opening position disengaging the housing module. The guide stem moves in the guide passageway as the closure member moves between the channel-opening position and channel-closing position. The spring yieldably urges the valve member to its channel-closing position.

Abstract: A cap for use with bottled water dispensing systems. The cap includes a main outer cap and an inner cap. The main outer cap has a central sleeve which receives and seals against a probe. The inner cap moves into and out of a sealing engagement with the central tube as the bottle is raised and lowered over the probe. The seal between the inner cap and the central tube is located on the outside surface of the central tube. The inner cap has a guide sleeve which centers the inner cap about the central tube, which is particularly important to achieve a proper attachment of the inner cap to the central tube during removal of the bottle from its support. The locations of the various components of the cap allow the cap to have effective differentials between the forces which are necessary to achieve proper sequencing of the formation of the various seals and connections which occur during use of the cap.

Abstract: Disclosed herein is a method of and apparatus for negative pressure dispensing of fluids wherein a dispense valve assembly (12) seals a container (18) and has valves (26) for ingress of ambient air and (38) for egress of dispensed fluid respectively, and a coupling head (58) mates with the dispense valve assembly and has a mechanism (62, 74, 84) operative to open the air and fluid valves and form a sealed connection (52, 84) solely with the fluid valve, such that fluid can be pumped out of the container via the fluid valve and the coupling head, whilst ambient air flows into the container via the air valve.

Abstract: The invention relates to devices for transferring, without the risk of contamination, products flowing out under gravity from an upper receptacle (1) or pipe (43) towards a lower receptacle (1) or pipe (16).The device [according to the invention] includes a hermetic enclosure (19, 45) covering the orifice (18, 44) of one of the receptacles or pipes (16, 43), it being possible for the mouth of the orifice (5, 11) of the other receptacle (1) or pipe to be inserted therein, this other receptacle (1) or pipe [includes closing-off means]including a flange (10, 14) capable of closing the enclosure (19, 45) when the mouth of the other receptacle is inserted therein so that a flow of inert gas can be driven through the inside volume of the hermetic enclosure (19, 14) preventing cross-contamination between the content of the receptacle (1) or pipe (43) and the ambient atmosphere.

Abstract: A filler head for a motor vehicle fuel tank filling pipe has a bowl-shaped body, the upper face of which includes a filling orifice. A shut-off valve is pivoted to the bowl of the body between a rest position, towards which it is resiliently biassed and in which it closes off the filling orifice, and a withdrawn position in which it lies within the bowl and in which the filling orifice is open. The valve is put into its withdrawn position by a filling nozzle when the latter is introduced into the filling orifice. The filler head has automatic locking means for locking the shut-off valve in its rest or closed position, with these locking means comprising an unlocking control member.

Abstract: A two-part coupling structure includes a male coupling part and a female coupling part which are mutually engageable to open fluid communication between a fluid-storage vessel and a conduit. The coupling parts are disengageable from one another to discontinue fluid communication between the vessel and the conduit, and also to close communication between ambient and each of the vessel and conduit. The retention volume of fluid which is trapped between the connected male and female coupling parts and which is exposed to or lost to ambient when the coupling parts are disconnected is very small. Because of particular structural features, the coupling parts will function reliably even with fluid having chunks or particulates of non-fluid material therein.

Abstract: A bag valve and spout for a bag-in-box bag wherein the bag valve is all plastic and recyclable. The bag valve is caused to rotate inside of the spout as a result of the hose connector being a screw threadedly connected to and disconnected from the bag valve. In the open position, holes in the bag valve align with holes in the spout, and vice versa for the closed position.

Abstract: A refillable compressed gas capsule, in particular, for household uses and for compressed-gas hand-operated devices, includes a valve body pretensioned by a spring and slidably held against a valve seat by the inner pressure of the compressed-gas capsule and against the pretension towards the interior of the capsule, which body is held in a holding means inserted into an opening provided in the face side of the capsule limiting the opening path of said valve body and comprising at least one opening leading into the interior of the capsule. In order to produce such a compressed-gas capsule in a very simple manner, it is provided that the holding means and the valve seat are held at least indirectly by an inwardly directed flanged edge of the capsule.

Abstract: A cap for use with bottled water dispensing systems. The cap includes a main outer cap and an inner cap. The main outer cap has a central sleeve which receives and seals against a probe. The inner cap moves into and out of a sealing engagement with the central tube as the bottle is raised and lowered over the probe. The seal between the inner cap and the central tube is located on the outside surface of the central tube. The inner cap has a guide sleeve which centers the inner cap about the central tube, which is particularly important to achieve a proper attachment of the inner cap to the central tube during removal of the bottle from its support. The locations of the various components of the cap allow the cap to have effective differentials between the forces which are necessary to achieve proper sequencing of the formation of the various seals and connections which occur during use of the cap.

Abstract: An aerosol dispenser filling apparatus in which a liquid, such as paint, containing cylinder (24) is removably mounted above an aerosol can receiving position above the cylinder into the cylinder which has an upper flared or expanded extremity (26) to guide the piston into the cylinder. The aerosol can (46) is connected to the bottom of the cylinder so that the liquid is forced from the cylinder into the can.

Abstract: A drug vessel suitable for aseptic mixing of a drug with a solvent or diluent and for parenteral administration of the resultant solution, which includes a cylindrical vessel body reduced in diameter at both sides thereof to form a narrow mouth portion at each end, and a seal member to be attached to each mouth portion of the vessel body for sealing the same.

Abstract: An alternative fuel system and compressed natural gas (CNG) conversion kit, primarily for smaller size industrial vehicles, such as compact loaders and lift trucks restricted in the space available in the engine compartment for the components of a CNG system where the vehicle was initially engineered for other fuel systems such as gasoline liquid petroleum gas (LPG) or diesel fuel having substantially fewer parts and components and less complex systems. A CNG tank is mounted horizontally outside of the engine compartment and a high pressure line connects from the tank to a regulator mounted inside the engine compartment for decompressing the gas to a pressure suitable for mixing with air in the carburetor of the engine. The CNG system has a refilling receptacle with an electrical interlock to the ignition preventing accidental drive-away.

Abstract: The prevent invention relates to a shutter of a leaf spring type supported at a filler neck portion of a fuel filler pipe by a shutter support portion within the filler pipe. The invention aims to improve a durability in opening and closing action of the shutter. The shutter according to the invention is formed to have an arm portion extending from a shutter working portion, the arm portion being elastically deformed when the shutter opens, and a turned end portion extending from the arm portion toward the shutter working portion. The turned end portion is held by the shutter support portion at a location near the shutter working portion such that deformation of the turned end portion is not restricted when it elastically deforms in accordance with the opening movement of the shutter.

Abstract: A fuel filler module fits in the filler pipe of an automotive fuel tank and includes a spring biased trap door that cooperates with a fuel nozzle restrictor to seal an open end of the filler pipe automatically when a fuel nozzle is withdrawn. The fuel filler module also includes a fuel nozzle guide that is part of a vent system for venting the fuel tank during the refuelling process and a splash guard feature that prevents splash back at the end of the refuelling process. The fuel filler module comprises four-snap together components that are largely plastic parts or assemblies of plastic parts that are designed for easy molding to facilitate economical manufacture.

Abstract: A cup is provided with a flexible lip containing a duct having an end provided with a flexible valve which is opened by pinching the lip; the duct communicates with a receptacle containing the beverage and the wall of the receptacle is made from a flexible material so as to expand when a liquid is injected into the receptacle and to exert on the liquid a pressure tending to expel the liquid from the receptacle; a cover is provided for storing the cup and includes a filling and washing area.

Abstract: Apparatus for the automatic fueling of automotive vehicles, comprising a robot which includes a fueling pistol and which is operative, to move the fueling pistol automatically from a rest position to a vehicle fueling location. The invention is characterized in that the fueling pistol (16) includes a rigid, first tubular element (20), which is intended to be moved by the robot (1) towards a receiving plate (21) provided with a hole and forming part of the vehicle fueling location. A flexible second tube (26), is arranged within the first, rigid tube (20) for movement from a first terminal position, in which the outer free end (27) of the second tube (26) is located within the first tube (20), to a second terminal position in which the second tube projects from the first tube. A pipe connector is provided between the hole and the fuel pipe of the vehicle.

Abstract: A closed granular chemical handling system comprising a dispensing valve and a receiving valve. The dispensing valve and the receiving valve are automatically opened when the valves are coupled together, and are automatically closed when the valves are uncoupled from one another. The valves are configured so that the receiving valve always is the first to open and the last to close. The valves are driven together by a camming structure having a neutral portion that acts as a delay between the opening and closing of both valves so as to allow granular material to flow from between the valves through the receiving valve.

Abstract: The device is intended for neutralizing a residual-pressure valve, without the need to remove it, for the purpose of filling the bottle. The device comprises a tubular housing (12) designed to be fastened, in the operative position, to a connection piece (2) of the bottle sealingly and comprising at least one first lateral connector (44) for connection to a gas source, a gripper (20) seated axially in the housing (12) and stressed by a spring (38) so as, in the operative position, to penetrate into the connection piece (2) round the rod (8) of the closing member (6), and an actuator for displacing the gripper (20) axially counter to the action of the spring (38) and for simultaneously closing it so as to drive the rod (8) and lift the closing member (6) from its seat.

Abstract: By employing two independent, separate and distinct flow paths which are controllably sequentially opened during use in a single actuation operation, an error-free, spill-free flame and explosion proof liquid delivery/filling system is achieved. In the preferred embodiment, both flow paths are normally maintained in a closed, sealed configuration, requiring an actuation force to controllably, sequentially open the flow paths. In addition, by providing a cooperating, mating liquid transfer assembly, the container on which the liquid delivery/filling system is mounted can be refilled with safety and ease, completely eliminating spillage of the liquid. In this way, a fully integrated, cooperating, liquid flow controlling system is realized.

Abstract: A dunnage bag valve and coupling arrangement comprises a valve stem having a spring loaded valve member which is movable to open a passage through the stem. A pair of circumferentially extending, diametrically opposed slots are formed on opposite sides of the stem. An axially extending opening is provided at one end of each slot for receiving a lug. A pair of lugs are formed on the inner cylindrical portion of a coupling so that the coupling can be pressed onto the stem and twisted, the lugs being introduced into the slot openings and then riding along the circumferential portions of the slots. An air hose is threaded to the coupling so that compressed air can be introduced through the valve stem into the dunnage bag. A fixed post inside the coupling opens the valve member when the coupling is engaged to the valve stem. To prevent rotation of the stem, teeth at the base of the stem engage teeth on the ring of a handle that is held while the coupling is pushed and twisted onto the valve stem.

Abstract: An oil drainage coupler that enables a single fitting to be coupled to associated oil drainage plugs of various sizes thereby enabling oil to be quickly drained from all makes and models of vehicles. This coupler produces a vacuum-tight seal that enables a vacuum pump to be used to enhance the rate at which oil is drained. The two halves of this coupler can be coupled by a rotation of one half into the other by an angle less than 90.degree., thereby making this a quick coupler that can be coupled by a single quick motion of vehicle service personnel.

Abstract: The invention relates to a cap for a hydraulic fluid reservoir for a brake circuit of a vehicle. According to the invention, it has a filling aperture (24) intended to be closed by a valve member (38) through the action of a spring (36) mounted in the cap (10) in order to allow the reservoir to be filled on the assembly line without removing the cap. The valve member (38) is axially movable against the spring (36) which returns it in a closed position. The valve member (38) preferably has a seal.

Abstract: A tank oil drain device comprises a drain receptacle associated with the tank, the receptacle defining a bore having a mouth opening to the tank exterior, the receptacle having a first port communicating between the tank interior and the bore; a plunger received in the bore, and a spring urging the plunger toward a position in the bore in which the first port is blocked; a seal normally sealing off between the bore and the side of the plunger at a location between the first port and the mouth; and lock structure carried by the receptacle, near the mouth, for retaining a tubular drain plug pushed into the bore for displacing the plunger in the bore sufficiently to unblock the first port thereby establishing oil draining communication via the first port and the plug to the exterior. The first port remains blocked by the plunger while the seal engages and seals off about the drain plug through a predetermined range of movement of the drain plug in the bore.

Abstract: A quick connect/disconnect assembly (10) comprises a male insert (50) secured to one end of a hose assembly (14), a separate female adapter (52) for attachment to an aerosol can (12), and dual seal arrangement (68, 70) within the adapter, and a releaseable latch (78) for positively interconnecting the insert and adapter. Upon insertion of the male insert (50), leakage of any fluid is contained within the female adapter (52).

Abstract: A seal for a fitting adapter for fluid couplings wherein a coupling probe is received within a recess within the other coupling half and the seal prevents the creation of subatmospheric pressures during withdrawal of the probe. The seal includes a lip or flapper valve component which establishes sealing during coupling pressurization, and permits atmospheric pressure to flow around the lip during coupling disconnection.

Abstract: An automatic shut-off nozzle for a vehicle servicing system can be rapidly mated to a receiver fitting on a fuel tank. Both the nozzle and the receiver have valves which are normally closed but which open when the nozzle is mated to the receiver. The nozzle includes a piston which moves so as to displace a spring-biased operculum forming the valve of the receiver; the piston is automatically retracted when the receiver is filled.

Abstract: A valve (20) has a valve housing (22) with a central passage (28) extending axially through the valve housing (22). Aperture (40) in the valve housing connect a second passage (38) to the central passage (28) to extend through the valve housing. A poppet valve member (24) is configured for sealing engagement of the central passage (28). The valve member (24) is urged into sealing engagement with the central passage (28) by internal pressure in a container (36) on which the valve (20) is provided. The valve member (24) and the valve housing (22) are configured so that the valve member (24) will drop away from sealing the central passage (28) when the pressure in the container (36) is insufficient to hold the valve member (24) in sealing position against the central passage (28) to leave the valve (20) in a permanently open state. An annular valve member (26) seals the second passage (38 ) in the same manner.

Abstract: A T-shaped manifold employs a single multiway control valve for purging and charging a cryogenic system of interest. The single multiway control valve is positioned at the intersection of a crossbar and perpendicular elongate member. One end of the crossbar is associated with a source of working gas. the opposite end of the crossbar provides a purge or check valve outlet. One end of the elongate member is connected to the multiway control valve and an opposite end is coupled by a VCO fitting to the cryogenic system of interest. At one setting, the single multiway control valve provides working gas to the system through the one end of the crossbar and elongate member. At a second setting, the multiway control valve allows gas to be vented from the system to ambient through the elongate member and the purge valve outlet. An in-line pressure gauge connected to the elongate member provides an indication of ingoing flow as well as outgoing flow of gas during respective charging and purging of the system.

Abstract: A container for receiving and retaining contents under pressure is provided with an improved valve structure to prevent contamination of the discharge valve during the filling operation. The valve structure includes a check valve which is opened when filling the container, and a sealing element which engages and surrounds a filling tube thereby preventing the contents from reaching the discharge valve. Additionally, purging of the discharge mechanism will clean the same of any residue that may be found therein.

Abstract: A liquid filling nozzle comprising a vertical tubular nozzle main body having a reduced diameter portion at an intermediate portion of its height, a damper attached to the lower end of the nozzle main body and pivotally movable upward and downward, a resistant member extending within the nozzle main body from the reduced diameter portion to a portion therebelow and movable upward and downward for acting against a liquid flowing downward, a member connecting free ends of the damper to the resistant member, and a resilient member biasing the resistant member upward.

Abstract: A self-contained tank filling fitting having dual operation wherein the fitting may be used with a gravity fluid supply system or a pressurized fluid supply system. The fitting includes an elbow having an upper end closed by a removable cap, and a pressurized filling port located in the bend of the elbow aligns with a tank port to reduce resistance to pressurized fluid filling. An automatic differential pressure valve controlled by a float operated vent automatically closes the pressurized filling port upon the tank being filled.

Abstract: Disclosed is a valve for use in a pressure-resistant container, permitting the full filling of the container with a liquefied gas thanks to a well controlled gas depletion path. The opening and closing of the depletion path is effected by bringing two opposing contact members apart and close to each other whereas the flow rate of gas depletion depends on the roughness of the contact surface areas of the opposing member. Such an appropriate depletion path can be made without difficulty such as encountered with formation of depletion path with recourse to machining.

Abstract: In a valve assembly receivable in an outwardly projecting neck in a keg, for normally sealing the keg and for cooperation with a detachable coupler by which the keg is tapped, the cylindrical spring retainer of the assembly has at its axially inner end deflector surfaces so liquid flowing inward along that cylindrical wall during filling of the keg through the gas passage of the valve assembly is deflected radially across the inner end edge of that wall as a sheet-like jet. This prevents upward spray out of the annular space between the siphon tube and the spring retainer, thus preventing overcarbonation, excessive foaming and underfilling of the keg.

Abstract: A fueling nozzle for closed circuit fuel systems comprising a body having a passage including inlet and outlet ends. A reciprocal plunger within the passage serves to open the fuel tank inlet and cooperates with a valve to close the nozzle when not in use. A reciprocal differential pressure actuated pressure regulating sleeve within the passage is positioned relative to a valve seat in accord with the nozzle fluid pressure and the nozzle passage is exposed only to regulated pressure. An indicator mounted on the body senses the position of the pressure regulator sleeve to give a visual indication of the position and condition of the regulator sleeve.

Abstract: A bulk syrup delivery system in which a compartmentized tank delivery truck includes a plurality of separate compartments or tanks, generally one for each of several different types of soft drink syrup. One multichannel delivery hose, having one channel or passageway for each type of syrup, extends from a hose reel on the delivery truck to a delivery receptacle at the account. The account has a plurality of separate storage tanks, each of which is coupled to the delivery receptacle, which is designed to couple to the end of the delivery hose, such that each compartment in the delivery truck couples to the proper storage tank in the account. A plurality of separate check or closure valves are installed in each side of the coupling between the hose and the delivery receptacle, such that flow therebetween is prevented until the valves are opened. The compartments in the delivery truck are pressurized (e.g.

Abstract: An improved fuel filler restrictor assembly including a reinforcing wall member adjacent to the aperture through which a fuel filling nozzle is inserted. The reinforcing wall member is secured to the filler neck restrictor body and extends across the filler tube with opposite edge portions adjacent to the filler tube wall so as to prevent prying of the restrictor assembly by a bar or the like and thereby to prevent removal of the restrictor portion of the assembly by back and forth prying movements by the bar.

Abstract: An insert is provided for a liquid inlet at the top of a tank not having a fill pipe for preventing liquid from a nozzle spout of a diameter greater than a predetermined dimension from filling the tank, and allowing liquid from a nozzle of smaller diameter to fill the tank to very near the top. The insert has a mouth with a wide opening at the top and an opening at the bottom just large enough to receive a spout having that predetermined diameter. A throat having an internal diameter slightly greater than that predetermined dimension extends from the bottom opening. A valve closes the throat under the force of a spring and a grid prevents the nozzle spout from being inserted past the end of the throat. Connected to the valve is a structure that is engaged by the nozzle when said spout is inserted into the throat to open the valve and permit liquid from the spout to pass into the tank.

Abstract: A separable coupling for filling or emptying a bulk container of a liquid or semi-liquid food product comprises a closure on the container, and a coupling member attached to a supply or discharge conduit and which is releasably connectable with the closure. Valves on the closure and coupling member are connected in series in the product flow path when the coupling is made. They are connected mechanically together and actuated in series so that the valve of the coupling member is actuated through the agency of the valve on the closure in a fail-safe manner. Provision is made for feeding superheated steam to the part of the product flow path lying between the valves, so that the exposed surfaces of the closure and coupling member can be sterilized or purged before and after a filling or discharging operation.

Abstract: A propellant charging head for filling a storing chamber of a propellant storage construction with a charge of propellant and method of making the charging head are provided, the head being adapted to be disposed against the construction and have a projection of the head engage a valve plunger of a valve unit disposed in the passage of the propellant storage construction so that propellant can flow from the head through the open valve unit to the chamber, the head having a generally conical nose-like member that is adapted to seat against a generally conical seat of the construction to fluidly interconnect the head to the passage.

Abstract: A tubular inlet for a fuel tank includes a transverse baffle having an opening sized to receive a fuel nozzle of a determined diameter, and apertures located laterally of said opening and which permit viewing of the tank interior when a nozzle is inserted into the said opening, the structure optionally including a movable shutter which is resilient biased to a position in which it closes said opening, the shutter being movable by said nozzle against said bias.

Abstract: An adapter for connection with the access valve fitting of a closed refrigeration system which includes a screw threaded coupling engaged with the externally threaded nipple on the refrigeration system with the adapter including a screw threaded adjustable abutment member in a normally open passage for automatically opening the normally closed "Schrader" valve with the adapter itself including a duplicate "Schrader" valve oriented in perpendicular relation to the axis of the existing "Schrader" valve and perpendicular to the longitudinal axis of the adapter itself with the adapter also including threaded fittings enabling connection with a pressure gauge, hose, closure cap, or the like.

Abstract: Joining apparatus between a container equipped in its upper part with a plug and the wall of a discharge enclosure provided with a horizontal orifice in the lower part thereof and located above said container, wherein the container is provided in its upper part with an adapting ring with respect to said wall and a second protective ring for the plug and the orifice is sealed by a detachable cover having gripping means and resting on a seat connected to said wall of the discharge enclosure.The apparatus is used for the dry transfer of fuel elements or nuclear waste to a reprocessing plant.

Abstract: A hermetically sealed high pressure gas container comprising a high stren chamber for confining the gas and a check valve fitted on and soldered to a boss formed integral with the chamber. The check valve serves as a temporary seal and permits the chamber to be charged with gas under atmospheric conditions. After charging, the inlet port of the check valve is soldered closed to provide a hermetic seal.

Abstract: An improved fuel filler restrictor assembly includes a reinforcing member adjacent the aperture through which a fuel filling nozzle is inserted. The reinforcing member is secured to the filler neck restrictor body by integral tabs and has projections extending radially inwardly beyond the minimum outer diameter of an unleaded fuel pump delivery nozzle. Restrictor tampering to permit unlawful use of leaded fuel is thereby inhibited.

Abstract: A filler tube assembly for a fuel tank of an automotive vehicle fabricated as an aluminum tube interference fit to a plastic housing through use of magnetic force having a flexible vent tube extending between the housing and the end of the tube to be inserted in the fuel tank.

Abstract: A toy balloon is automatically filled with helium gas using a system responsive to gas pressure. A novel check valve in the neck of the balloon is automatically opened upon insertion of a filler element. The flow of gas to the filler element from a constant pressure source is initiated by operation of a pushbutton which opens a valve which is resettable as a result of subsequent pressure build-up in the system. Opening of this valve results in opening a pilot valve through which gas flows to the balloon. Opening of the pushbutton operated valve also applies pressure to an expansible chamber of a timer valve through conduit means and when the pressure in such conduit means and in said expansible chamber become sufficiently high after a predetermined time (established to some degree by conditions in the nozzle and check valve) the timer valve is operated to apply gas pressure to an expansible chamber of the pushbutton valve to return it to its closed position thereby interrupting all flow to the balloon.

Abstract: Disclosed is a single piece integrally formed safety closure for a container including a body portion designed for fluid tight engagement with the neck and finish of a container and a depending portion including a passageway which extends into the container. A valve is integrally formed in the side wall of the closure and opens upon insertion of a dropper-dispenser. The valve closes upon removal of the dropper, thereby preventing spillage or inadvertent removal of the contents of the container.

Abstract: A fuel dispensing nozzle capable of sealably engaging a baffled filler pipe during a tank filling operation; a longitudinally slidable sleeve or member carried on the nozzle's discharge tube permits use of the nozzle in tank filler pipes having a deep set baffle, thereby facilitating the introduction of fuel into said tank.

Abstract: A fuel container with a filling valve, especially for a refillable cigarette or cigar lighter, comprises a partition or shield surrounding the movable valve member and provided with a small-section orifice to prevent entry of fibrous material which may block self-closure of the valve.