Abstract: A concrete filled tube column includes: an outer tube connected to beams of the structure, the outer tube consisting of a plurality of tube pieces coaxially disposed in series; a concrete core disposed within the outer tube; an inner flange peripherally mounted on the inner face of each tube piece; and a concrete layer peripherally disposed on the inner face of each tube piece. The concrete layer includes a tubular portion positioned under the inner flange and in direct contact with the entire lower side of the inner flange. The tubular portion has an inner peripheral face tapering upward so that the transverse inner size at the lower end of the tubular portion is equal to the transverse inner size of each tube piece. In constructing the column, a plurality of the precast structural tubes, each including: the tube piece; the inner flange; and the concrete layer, are prepared. Then, one of the precast tubes is erected. Concrete is placed within the erected precast tube to form a concrete core.

Abstract: The cup filling unit includes a guided circulating feed means which carries cup receptacles positioned in rows transverse to the feed direction. The cup receptacles also follow feed paths parallel to the feed direction. An elevator is provided for feeding cup and/or cover stacks in an added cup and/or cover feed device. The carrier of the elevator engages under a cup and/or cover stack and raises it from below axially into a lower opening of a shaft of an intermediate magazine. Each lower opening is associated with an engagable or disengagable supporting base for gripping under or delivering an overlapping cup and/or cover stack. The intermediate magazine is movable and displaceable from its filling position into a discharging position. In the discharging position the lower opening of the intermediate magazine substantially coincides with the upper opening of a cup and/or cover delivery magazine positioned above the cup and/or cover delivery station.

Abstract: This air operated plastic pail capper machine is designed to quickly and effectively push a cover onto a pail, while also pushing out any air that may be above the contents of the pail. Primarily, it consists of a base with rollers on top for easy alignment of a pail with a plate attached to a piston rod of an air cylinder, and the air cylinder is mounted to a sleeve attached to a post secured to the base of the machine. Palm operated valves are also employed to operate the machine.

Abstract: A device and method for bagging thin flexible members such as a stack of tortillas having a curved pan for accepting and bending the stack of tortillas, a bagging head for opening and positioning a bag adjacent curved pan and an actuator for inserting the curved pan with the stack of tortillas thereon into the opened bag and transferring the bag with the tortillas therein onto a conveyor.

Abstract: An apparatus for automatically collecting and packing a selected number of units of product in flexible bags into a carton in a vertical orientation. The apparatus includes a collecting assembly for receiving and positioning a row of such units in an inclined position. An assembly is provided to transport the inclined row of units from the collecting assembly to a loading station. The loading station is operable to raise one or more rows transported thereto from their inclined position to a substantially vertical position, then plunge the vertically positioned units into a carton. A controller is provided for synchronizing the relative operation of the apparatus.

Abstract: Packaging of series of relatively small articles between long webs of wide packaging laminates having faces of resilient heat sealable foam. One web is fed foam-face-up across a table, the articles to be packaged placed on it in spaced locations, heated melting shoes applied to web edges to melt the foam surfaces there, and a second web applied foam-face-down over the spaced articles and heat sealed to the lower web at its melted edges. Melting shoes can have their surfaces treated to make them essentially non-wetable by the melted foam. Transverse heat sealing and severings are effected between successive articles. The heat sealings can be set by cold pressings. Web backings can be made relatively non-porous to minimize bleed-through of melted foam. Before sealing, sandwiched articles and be pressed between upper and lower resilient fingers to urge articles to level at which they project up as much as they project down, from plane of web edges.

Abstract: To retain compressible articles such as paper towels, toilet paper and the like tightly compressed in a weldable foil, a feeding push element (3) pushes the articles into a bag and, in accordance with the invention, the bottom of the bag is yieldingly restrained to permit movement of the articles into the bag while displacing the bag against a yielding force. When the bag is filled, the counter abutment plate (6) adjacent the bottom of the bag has reached a limit or terminal position, so that articles in the bag are compressed. Hold-down elements then close over the still open end of the bag, permitting sealing of the still open bag while the articles are retained compressed. The abutment plate can then be moved out of position for further transport of the filled bag with the material retained therein in compressed condition.

Abstract: A hopple for developing a trotting gait for horses which includes two sets of diagonally disposed hopple loops which encircle a horse's legs and which are connected so as to fetter the horse's legs diagonally through a motion transfer assembly mounted beneath the horse's belly and which assembly permits the front and rear legs of the horse to be linearly restrained so that the legs are diagonally fettered without the imposition of lateral stress.

Abstract: A hydraulic system (30) suitable for raising, lowering, floating and locking a cutting deck (16). Hydraulic circuit (30) preferably includes a back pressure system (40) for automatically, or manually, applying a preferred back pressure to hydraulic cylinders (24) to "float" decks (16). Connected to back pressure system (40) is an actuation system (42) which can automatically or manually act on back pressure system (40) to change the back pressure depending on conditions. For example, it may be desirable to increase the back pressure when mower (10) encounters a hill to transfer more weight from the cutting unit (16) to the traction vehicle (12) of mower (10).

Abstract: A mower bar is disclosed having rotating cutters driven by vertical drive shafts and associated gearing. The mower bar includes an air duct along its forward edge and at each rotating cutter. Air ducts are also included in each cutters' centered dish portion.

Abstract: A harvesting arrangement for harvesting corn and other grain fruits and formed as a front implement of a harvester thresher, the harvesting arrangement comprises drawing devices for drawing harvested product from the field, a picking gap for separating ears from stalks, a picking roller which is only one for each stalk row, the picking roller including a substantially cylindrical base body with a casing provided with a plurality of impact plates having cut outs, a cutting device including a plurality of individual cutters each having a free-running end which faces toward the base body and an opposite end which faces away from the base body, the casing of the base body having a plurality of recesses in which the free running ends of the cutters are introduced, and holding elements arranged to support the opposite ends of the cutters adjustably relative to the base body.

Abstract: A lawn mower attachment that allows the lawn mower to pulverize the lawn clippings into a mulch. The mulching attachment mounts over the opening to the discharge chute (90). It consists of equally spaced rods (30) that form a grid. This grid permits air to escape while filtering the mulched material. Each rod (30) is suspended such that it is free to rotate about its longitudinal axis, move vertically in response to the terrain, and pivot about the suspended end. The pivot motion is constrained in angular displacement so as not to decrease the mulching capability. The vertical, rotating, and pivoting motion of the rods act to cleanse the grid and return the residue for further trituration. Limiting the grid rod motion insures grid integrity thus insuring that only properly prepared residue escapes.

Abstract: The invention relates to a machine for working grass, hay or other crops on the field, provided with two rake members which are drivable about upwardly directed axes of rotation. During operation, the distance between the rake members can be changed by controls at the seat of the tractor on which the machine is mounted to adapt the machine to various circumstances. The machine is provided with swath forming crop guide members, the relative positions of which are automatically adapted to remain about the same irrespective of the distance between the rake members.

Abstract: A steam piston balance means for a turbine engine comprises, in one form, a pressure chamber and means for supplying steam to the chamber to apply a force to walls of the chamber. The chamber is defined, in part, by an inner surface portion of a member connected and rotating with a portion of a thrust bearing whereby pressure force applied on the inner surface in turn applies a tractor force on the thrust bearing.

Abstract: The present invention provides a method for the destruction of hazardous carbonaceous wastes by the plug flow, thermal combustion of said wastes comprising (a) obtaining an intimate admixture of vaporized fuel and air, said admixture containing at least a stoichiometric amount of air, (b) passing said admixture to a plug flow combustion zone, and (c) effecting sustained and essentially complete combustion of said fuel under essentially adiabatic conditions to destroy said wastes and to form a combustion effluent of high thermal energy; said combustion being characterized by said fuel-air admixture having an adiabatic flame temperature such that that actual flame temperature in the combustion zone is greater than about 1350K.

Abstract: Weight and spatial concerns in aircraft are alleviated or minimized through a combined auxiliary and emergency power unit including a gear box 10 adapted to drive a generator 16 and a hydraulic pump 18 as auxiliary to emergency power supplies for the aircraft. The system includes a pair of turbine wheels 22 and 24 along with a pair of motion transmitting paths 12, 26, 42; 14, 68, each including a selectively operable clutch 42, 68 so as to connect the turbine wheels 22, 24 to the gear box 10 in mechanical parallel. A rotary compressor 28 is connected to one of the turbine wheels 22 and an associated combustor 46 provides combustion gas to the turbine wheel 22 for auxiliary power unit operation. A pressure tank 56 for compressed oxidant and an additional combustor 60 are utilized to provide combustion gas to the other turbine wheel 24 in an emergency power unit mode of operation.

Abstract: When a stall is dectected during high power operation, the engine is given one chance to recover without a change in bleed schedule. Should a record stall occur within 10 seconds the control system switches to an override bleed schedule for 51/2 minutes, or until throttle is reduced. This supplies a minimum adaquate thrust for a limited time.

Abstract: Continuous combustion heat engine including a compressor (12), combustor (14) and expander (16) which operates on a Brayton cycle with positive displacement pistons (90) in the compressor and variable expansion ratio pistons (190) in the expander. Compressor (12) delivers compressed air to the combustor (14) where it is mixed with fuel and combusted to produce expansion gases for the expander (16). Power input to the compressor and power output from the expander are achieved through the radially disposed pistons (90,190), connecting rods (94), cranks (98), crank shafts (100), planetary gears (104), sun gears (106) and sun gear connectors (114) which rotatably secure the sun gears (106) and manifolds (110,166) together. The pistons (190) for the expander have positive displacement sections (192) and free floating sections (200) for the variable volume ratio capability.

Abstract: The use of a single main centrifugal fuel pump for supplying fuel to an aircraft gas turbine engine has advantages over other known systems, however a problem has existed in that the centrifugal pump, when driven in a fixed ratio to the engine speed, cannot deliver fuel at adequate pressure under engine starting conditions. The disclosed fuel supply system using a main centrifugal pump overcomes this shortcoming by having a turbine-driven start pump added to the fuel supply with both the turbine and the start pump receiving fuel pumped by the main centrifugal pump and the turbine utiliziing the high flow, low pressure fuel to drive the start pump which incresases the pressure of the fuel to a value adequate for engine starting. The start pump delivers fuel until such time as the main centrifugal fuel pump has reached a speed to provide the fuel to the engine at the required pressure, at which time the turbine is no longer driven and the output of the start pump goes to zero.

Abstract: A regulating system for regulating a double-shaft gas turbine, wherein simultaneously: the fuel feed electrovalve is governed by a signal proportional to the difference between the number of revolutions per minute of the power turbine and a reference value; the movable nozzles of the power turbine are governed by a signal either proportional to the difference between the number of revolutions per minute of the compressor and a reference value, or proportional to the difference between the temperature of the exhaust gases and a relevant reference value; and the movable stator-blades of the compressor are governed by a signal proportional to the ratio between the revolutions per minute of the compressor to the square root of the ratio of the absolute ambient temperature to an absolute reference or design temperature.

Abstract: A thin membrane of high strength but ductile material is placed over a perforated structural support, thus allowing high pressure on the membrane side of the support to separate one chamber from another. Upon application of pressure through the perforated structural supporting structure, the membrane will collapse allowing communication between chambers. The arrangement has utility in rocket motors and gas generators where discrete impulse segments are desired to be available on command, and may be fabricated in concentric or tandem (series) volumes.

Abstract: An augmentor liner 16 for a gas turbine engine is formed of thin perforated material and has pressurized cooling air surrounding it. A stiffner ring 42 is supporter from the liner with radially flexible straps 52, while relative radial displacement is limited by clips 50, 44. The liner is restrained from buckling while permitting thermal expansion.

Abstract: An exhaust system having a protective arrangement includes a plurality of spaced overlapping inclined armor plate blockers providing a ballistic shield over the entire exhaust area. A louvered grate is provided extending between the tops of the blockers to permit egress of gases from the engine but to block destructive elements from being thrown into the interior of an engine. Cooling air is supplied to the blockers and is caused to move along a path which carries it across the surfaces of the blockers so as to materially reduce the temperature of these surfaces. Further, this cooling air is directed not only over surfaces of the blockers which are directly visible externally of the vehicle, but also over a surface which, while not directly visible from the exterior of the vehicle, is a potential source of reflected heat which could be sensed exteriorly of the vehicle.

Abstract: An exhaust nozzle extends from an engine nacelle and has an opening disposed at an acute angle such that the exhaust stream is blown over a length of the propeller blade. The opening has a plurality of guide vanes disposed therein to shape the exhaust stream most effectively. By spreading the exhaust stream over the length of a propeller, mixing of the exhaust stream with ambient air is maximized, thereby lowering the temperature of the exhaust stream to tolerable levels.

Abstract: An improved method for removing solid particulate matter from the exhaust of a diesel engine, having the steps of passing the engine's exhaust flow through at least a part of filter means to trap solid particulate matter contained initially in the exhaust, thereby to remove said matter from said exhaust flow, periodically interrupting the exhaust flow through at least said part of the filter means, passing, during said interruption, at least one backflush fluid pulse through at least said part of the filter means thereby to dislodge from the filter means, and entrain, said solid particulate matter, and transporting said dislodged solid particulate matter to the intake of said engine so that said matter can be combusted in the engine, wherein the improvement comprises purge means advantageously positioned so as to allow the discharge of noncombustible particulate matter from the engine before it accumulates to a harmful level.

Abstract: A control device for a hydrostatic drive for at least two actuators having a variable displacement pump whose adjusting device can be acted on as a function of the displacement and/or of the delivery pressure, wherein a control valve is associated with each actuator in its hydraulic supply line and the delivery flow for each actuator is determined by means of a pressure compensator as a function of the valve preset at the control valve, is simplified while ensuring accurate control. This is achieved by having the adjusting device always set the pump at a displacement which is slightly less than the sum of the actual instantaneous volume flows required by the actuators.

Abstract: A hydraulically operated continuously variable transmission includes a hydraulic pump coupled to an input shaft, a hydraulic motor coupled to an output shaft, a closed hydraulic circuit interconnecting the hydraulic pump and the hydraulic motor, a hydraulic actuator for actuating a controlled member in the closed hydraulic circuit, an auxiliary pump connectable to the closed hydraulic circuit and the hydraulic actuator, a supply oil passage for supplying oil discharged from the auxiliary pump to the hydraulic actuator, and a control valve coupled between the supply oil passage, the closed hydraulic circuit, and an oil tank. The control valve comprises a hydraulic chamber communicating with the supply oil passage, a spring, and a spool disposed between the hydraulic chamber and the spring.

Abstract: An actuator including a device made of thin film shape memory material mounted to a substrate. The thin film device is deformed from its original shape. Thereafter, the device is heated to restore the device to its original shape. Motion of the device occurs in the deforming and restoring steps, which is used to produce some form of work result.

Abstract: A suction type turbo-supercharger (6) is driven by highly negative pressure suction air produced by a negative pressure generator (4) which accelerates the exhaust gas stream of an internal combustion engine (1), external air being drawn by the negative pressure into the suction turbine (61) of the turbo-supercharger (6) to rotate the supercharging turbine (62) coaxial and coupled with the suction turbine (61) to thereby supercharge the air fed into the combustion chamber of the engine. The air stream produced by the negative pressure drives the turbo-supercharger and may also be used to cool the engine, in which case the turbo-supercharger is driven by the air stream after cooling the engine.

Abstract: There is provided an apparatus and method for generating power from a working fluid wherein the working fluid is a saturated vapor or superheated vapor generated in a high pressure zone where the working fluid is used to impart work to a working shaft by means of directly linked high and low pressure cylinder piston assemblies located in the high pressure zone and a lower pressure zone, respectively.

Abstract: A gas turbine engine combustor is provided with a semi-spherical upstream wall constituted by two correspondingly shaped skins which are spaced apart by pedestals attached to one of the skins to define a space between them. Cooling air is progressively metered into to space through apertures in the first upstream skin to provide effective cooling of the second downstream skin. The cooling air is exhausted from the space through an outlet defined by the first skin and the periphery of the second skin to provide film coating of the upstream end of the combustor side wall.

Abstract: Aircraft engine cooling apparatus having a plurality of cooling gas inlet nozzles, producing first streams of cooling gas moving in a forward direction, a plurality of first direction reversal members for splitting the first streams into second and third streams straddling the nozzles, and substantially reversed in direction relative to the direction of the first streams, a plurality of second direction reversal members, positioned between pairs of adjacent nozzles, for again substantially reversing the directions of the second and third streams, while combining the second and third streams to form a fourth stream of laminar flow cooling film, and wherein adjacent pairs of the first direction reversal members have wall portions configured to form gradually diverging channels through which the fourth stream cooling film moves.

Abstract: A method and apparatus for electronically pressure sealing and leak testing an idle centrifugal chiller system wherein a small positive differential is maintained between the internal refrigerant vessel pressure of the chiller system and the ambient atmosphere. This differential pressure is maintained by selectively applying heat to the refrigerant.

Abstract: An air conditioning process and apparatus with absorption of water vapor in a circulating absorption liquid containing an aqueous salt solution. The absorption liquid to be supplied to the absorber is cooled by indirect contact with a circulating water stream in a heat exchanger. The circulating water is expanded at reduced pressure to release water vapor and lower the temperature of the water. The water vapor is thereafter absorbed in absorption liquid from the absorber.

Abstract: An ice storage refrigerating apparatus of direct contact type comprises a closed crystallizer tank containing water therein and a refrigerant circulating system. A refrigerant consisting essentially of a hydrocarbon having four carbon atoms and/or a hydrocarbon having five carbon atoms is brought into direct contact with the water contained in the crystallizer tank to form ice in sherbet form which is used for heat exchange to provide chilled water used for air conditioning.

Abstract: An automobile air conditioner system includes a variable displacement compressor having a wobble plate and a pressure control valve disposed in the compressor for controlling the pressure in a crank chamber. The pressure control valve is operative under the control of predetermined conditions, such as the temperature of an evaporator.

Abstract: A control device for adjusting the radial position of the sinkers in a circular knitting machine, consitituted by a couple of cams for the radial drive of the sinkers. The cams are co-planar and concentrical with the axis of the cylinder and substantially circular. The innermost cam is stationary. The outermost cam is radially approachable and pushable away due to the effect of a countercam externally placed around the outermost cam and provided with approaching and pushing-away lengths, which, by means of the countercam's discrete revolution, radially approaches the outermost cam, and pushes the outermost cam away.

Abstract: A locking device comprising a hasp rod having two limb portions and a pair of locking plate hingedly connected together along one of said limb portions of said hasp rod, said locking plate adapted for relative swinging movement between an open position where said plates permit access to said other limb of said hasp rod and a closed position where said plates clasp said other limb of said hasp rod between said plates; said plates including aligned passages for receiving padlocks to lockingly secure said plates in said closed position.

Abstract: A door latch and lock mechanism especially for storm doors and screen doors, having a latch and a lock bolt. The latch can be retracted from the outside by a button which pushes a plunger in a lengthwise direction. When the plunger is rotated in one direction it will lock the latch in the latched position and also extend the locking bolt to its locked position. When the plunger is rotated in the opposite direction, the latch is released and the bolt is retracted. The plunger is rotated in one direction or the other from the outside of the door by a key operated mechanism spaced from the push button and operatively connected to the plunger by connecting links.

Abstract: A tandem rolling mill is operated such that roll stands of an upstream stage of the mill adjacent to a strip inlet thereof are positioned relative to each other to effect a strip crown control or an edge drop control, while roll stands of a downstream stage of the mill adjacent to a strip outlet thereof are operated to axially shift the downstream stage work rolls cyclically to distribute roll wear and thermal crown in the axial direction thereof.

Abstract: Apparatus for producing panel roofing includes a platform mounted on an elevating mechanism. A panel producing machine is mounted on a support stand which in turn rides on tracks along a length dimension of the platform. A decoiler for decoiling metal sheet stock fed into the machine also rides on tracks along the platform length. The machine is oriented to produce panels in a direction perpendicular to the platform length dimension. With the platform elevated to roof edge and its length dimension parallel to that edge, the panel producing machine and decoiler are moved along the platform following extrusion of each successive roofing panel. In a preferred embodiment, the machine can be pitched to match a pitch of the roof to facilitate panel production.

Abstract: To avoid impacts on the first pass of the rolled product through a universal rolling mill the vertical rolls of the rolling mill can be provided with their own integral drive according to our invention. In an electrical drive for a vertical roll the vertical roll is the rotor of an electric motor while the stator is a circular collar on a nonrotatable supporting axle for the vertical roll. In a hydraulic drive for a vertical roll a hydraulic motor is either located in a housing side extension of the structural member supporting the vertical roll to drive it from the outside by spur wheel gearing or by a frictional drive or the hydraulic motor is mounted in the nonrotating supporting axle of the vertical roll and engages on an inner cogged drive ring on the vertical roll from the inside by spur gearing positioned on a transverse plane.

Abstract: A rivet setting tool comprises a feed device which can be actuated for a rivet upsetting operation and which imparts an axial movement to the rivet pin. The feed device includes a piston-cylinder assembly formed by a working piston and a pressing piston. A trigger is arranged to apply pressure to a control valve rod which by its movement opens and closes communicating openings for a pressure fluid in the tool. The trigger is movable in a plane which is inclined with respect to the axis of the control valve rod and when actuated comes into sliding contact by means of a lower rearward edge with an upper end face of the control valve rod to displace it axially.

Abstract: A riveting head for coupling to a stapling apparatus, which is provided with a covering body, a member for removably engaging the covering body with the stapling apparatus, a pulling unit movably mounted within the covering body and formed to grip a stem in turn formed with a frangible head at one end thereof, in addition to an anvil bushing positioned on the covering body through which the stem extends when gripped by the pulling unit, and a multiplying lever pivotally mounted upon the covering body. The pulling unit is movably mounted upon the covering body through the multiplying lever which is provided with an end positioned to be actuated by a lever of the stapling apparatus.

Abstract: An electronic torque wrench equipped with at least two strain gages placed on both sides of a crosswise plane on a part forming a sensor and each supplying an output voltage, C.sub.1 and C.sub.2 respectively, which, depending on torque C applied by the wrench to an actuation point A, reacts on an electronic circuit indicating this torque. The wrench comprises a first electronic circuit for determining and storing a constant factor k during a calibration measurement for which torque C is applied at actuation point A is made zero by a parasitic force F' applied in the opposite direction of actuation force F and at a point E of the wrench other than point B of application of the latter force F, the constant factor k being used during each use of the wrench by the electronic circuit to determine, with second circuit and by application of the formula C=C.sub.1 +k(C.sub.1 -C.sub.2), the value of torque C applied to actuation point A as a function of torques C.sub.1 and C.sub.

Abstract: The present invention provides a method and system which is useful on instruments requiring experimentally determined calibration curves by which calibration data can be transferred to a plurality of field gauges, thereby avoiding the necessity of individually calibrating each gauge each time calibration is necessary. The field gauges are initially cross related to a master gauge. At a later time when a new calibration is necessary, the master gauge is calibrated using carefully prepared samples of a test material. Using the experimentally derived calibration curves with the cross relation data provides calibration data for the field gauges.

Abstract: A liquid sample to be analyzed is subjected to a vaporizing step. The vaporized components are submitted to a first separation stage by introducing said components into a packed chromatography column and flowing carrier gas through said column. The effluent of the first stage is passed through a flow dividing chamber. A second separation stage is performed by passing the effluent of the flow dividing chamber to a capillary chromatography column and flowing carrier gas therethrough. After a predetermined period of time, flushing gas is introduced through the flow dividing chamber and flowed through the first-stage packed column in a direction opposite to the original direction of flow while the direction of flow remains unchanged in the capillary column.

Abstract: In order to evaluate the condensation amount in a jet engine intake duct, for calibrating the engine, apparatus are provided which induce a high speed flow of air through a duct. The duct is designed so that the air velocity within it very gradually increases along it until a choked (sonic) condition is reached. At or around sonic conditions static pressure is very responsive to changes in flow due to condensation. Thus by first obtaining a pressure profile along the duct under non-condensing conditions and then comparing this with a pressure profile under condensing conditions a condensation amount can be computed.

Abstract: For making rapid, non-destructive permeability measurements in the field, a portable minipermeameter of the kind having a manually-operated gas injection tip is provided with a microcomputer system which operates a flow controller to precisely regulate gas flow rate to a test sample, and reads a pressure sensor which senses the pressure across the test sample. The microcomputer system automatically turns on the gas supply at the start of each measurement, senses when a steady-state is reached, collects and records pressure and flow rate data, and shuts off the gas supply immediately after the measurement is completed. Preferably temperature is also sensed to correct for changes in gas viscosity. The microcomputer system may also provide automatic zero-point adjustment, sensor calibration, over-range sensing, and may select controllers, sensors, and set-points for obtaining the most precise measurements. Electronic sensors may provide increased accuracy and precision.

Abstract: A poppet valve is mounted internally of a core tranfer piston of a core testing device. The valve face of the poppet valve is smoothly configured so that particulate matter will not cling thereto. A flow of gas is provided to blow debris away from the poppet valve assembly into the external environment.