Abstract: An electronic type air/fuel ratio control system for use in gasoline engines comprises an accelerator, a detector of the manipulation angle of the accelerator, a shunt conduit by-passing a throttle valve, an air by-pass valve exposed in the shunt conduit for controlling flow rate of by-pass air, and a control circuit. The control circuit is responsive to the output of the accelerator manipulation angle detector and generates a control signal for the air by-pass valve, whereby the air/fuel ratio can be controlled with high accuracy when the flow rate of air is low.

Abstract: A temperature-detection type change-over valve for switching the state of communication between a plurality of passages, suitable for use in combination with a controller for controlling the operation of an internal combustion engine. The valve has a thermally expandable member adapted to expand when heated, a shaft adapted to be pressed and moved in one direction as the thermally expandable member expands, a valve movable following the movement of the shaft between a first and a second position for switching the state of communication of passages, and a tension spring disposed to surround the shaft and adapted to exert a biasing force to act against the force generated by the expansion of the thermally expandable member.

Abstract: An altitude compensation ignition system for compensating ignition timing of an internal combustion engine depending upon variations in altitude or atmospheric pressure comprises pressure sensitive compensation means consisting of a bellows whose ends are fixed to a distributor and a vacuum advance device and adapted to be elongated and shortened in response to variations in atmospheric pressure. When the atmospheric pressure is lowered, the bellows is elongated to move a contact point relative to a rotor of the distributor, thereby advancing the ignition timing.

Abstract: An ignition timing control system for retarding the spark of a spark plug wherein the ignition timing is regulated to be practically constant while the engine speed is within a low range, but wherein the ignition timing is retarded in proportion to an increase in engine speed as the engine speed increases over a given speed. The system is applicable to capacitive discharge ignition systems and includes a control circuit for triggering the capacitive discharge system as a function of engine speed. The control circuit includes a pick-up coil for generating a voltage having an amplitude proportional to engine speed, and for providing a trigger signal at the peak of the voltage waveform when the voltage waveform is below a preset value. When the voltage waveform exceeds this value, as determined by a limit circuit, the trigger signal is generated as the voltage waveform falls from its peak and reaches the preset value.

Abstract: A fuel metering apparatus is shown as having a throttle body with induction passage means therethrough and a throttle valve for controlling flow through the induction passage means, fuel under superatmospheric pressure is metered and such metered fuel is supplied to a fuel discharge nozzle situated within the induction passage means downstream of the throttle valve; a first air flow is supplied to the metered fuel upstream of the fuel discharge nozzle as to cause the metered fuel to at least start to undergo atomization even before being discharged at the discharge nozzle; a second air flow is also supplied to the fuel discharge nozzle as to at idle engine speed flow sonically therethrough, and additional throttling valving means are provided for controlling the air flow to the fuel discharge nozzle.

Abstract: A fuel control system for an internal combustion engine in which the accelerator pedal is set by the operator and defines an air flow control variable which is applied to a control loop that actuates a servo motor or other suitable rotary means to set the relative position of an air flow control flap within the induction tube. The control loop attempts to maintain the position of the air flow flap in continuous correspondence with the accelerator pedal position. The actuating current for the final control element is used as one input datum for a stored data field. Another input variable to the data field is the actual position of the air flow valve or flap. The data field contains empirically obtained data relating these two variables with the prevailing air flow rate and generates an output signal that is used as the air flow rate signal in a control pulse generator. The control pulse generator also receives other signals related, for example, to temperature, engine speed, etc.

Abstract: A fuel control system for improving the driveability of a high power to weight ratio vehicle by using power as the controlled parameter. In the system, an operator command signal is compared to a quantity of fuel per engine revolution signal to develop an error signal proportional to the difference between actual power being delivered from the engine and operator commanded power.

Abstract: There is described a method and an apparatus for use with the fuel preparation system of an internal combustion engine, for example, a fuel injection system which operates injection valves with electrical control pulses. When the gas pedal of a vehicle is actuated abruptly, the air flow measuring device of such systems is subject to oscillations around its equilibrium point, and the initial one of these swings is used to cause enrichment of the fuel-air mixture. The return swing generates an undesired lean signal which is suppressed by a "damping circuit". In addition, there is provided mixture enriching during steady applications of the gas pedal by means of a time-decaying enrichment signal generated by a slow acting circuit which operates in superposition to the action of the damping circuit. Both circuits may be suppressed by a blocking circuit during certain engine conditions, for example, during engine starting and engine overrunning as well as on the basis of temperature.

Abstract: An internal combustion engine dual fuel system for controllably running the internal combustion engine on a liquid fuel, such as gasoline, in the usual manner or, at will, on liquified petroleum (LP) gaseous fuel. The conventional liquid fuel system of the internal combustion engine is unmodified except for the addition of a remotely controlled shut-off valve in the fuel line at the carburetor fuel inlet. An LP gas suction verturi is disposed in the air induction flow to the carburetor inlet, for example by being mounted in the air filter above the carburetor inlet, and is supplied in fuel from the vapor phase of an LP gas, such as butane or propane, above the level of the liquified gas in an appropriate tank. The LP gas tank and the line supplying the gas to the carburetor air inlet are maintained at a substantially constant temperature via a by-pass of the engine coolant circuit, the flow of coolant through the by-pass being automatically controlled by a thermostat.

Abstract: A vaporization chamber for an internal combustion engine, the engine having a liquid fuel reservoir and an intake manifold, the generator serving to convert liquid fuel to a combustible gas mixture including a vaporization chamber the outlet of which is connected to the engine intake manifold, a plurality of small diameter tubular reeds extending within the vaporization chamber and communicating with the inlet and means of introducing liquid fuel from the fuel reservoir and air through the reeds into the vaporization chamber.

Abstract: Apparatus for controlling exhaust gas recirculation in an internal combustion engine employs a first control valve in an exhaust gas recirculation passageway, a second control valve in an air conduit connecting the intake passage to atmosphere through selective restriction means, and a regulating valve responsive to differential vacuum intensities for actuating the control valves. The restriction means comprise a plurality of individual restrictions one or more of which are selectively put into operation depending upon engine operating parameters such as coolant temperature and driving speed.

Abstract: To simplify a Wiegand wire type pulse source, a Wiegand wire (4) has a coil (3) wound thereon. A permanent magnet (5) is positioned with a gap from the coil, and a magnetically permeable masking element, for example a sector-shaped disk, is movable between the magnet and the coil. The coil (3) is connected to a source of direct current (B) which so magnetizes the Wiegand wire (4) that, when a gap of the masking element occurs between the magnet (5) and the coil (3), the Wiegand wire is reversely magnetized until, again, a solid portion of the masking element is interposed in the gap between magnet (5) and coil (3) to restore the magnetic direction due to the battery (B). Re-magnetization pulses are picked off the coil (3) by a suitable pulse coupling element such as a capacitor (C).

Abstract: A ball projecting apparatus is described, including a spring biased plunger for striking a hollow ball positioned within a guide tube to project the ball out of such tube. The ball projecting apparatus is useful as a baseball hitting trainer. An adjustment device is provided for changing the position where the plunger inpacts that ball to enable the path of the ball to curve to the left or right to simulate baseball pitching. Also the top half of the guide tube is removed to reduce its resistance to lateral spin of the ball across its direction of travel. In one embodiment, the plunger impact position is adjusted by changing the angle of the plunger shaft relative to the ball guide tube axis. In another embodiment, this adjustment is achieved by supporting the plunger shaft substantially parallel to the guide tube axis but spaced therefrom and rotating such plunger shaft about such axis into different rotational positions relative to the center of the ball.

Abstract: An efficient, clean burning, woodburning stove in which super heated fresh air and exhaust gases from the primary combustion of the wood fire are introduced into a secondary combustion chamber wherein these gases are mixed to recombust remaining fuel particles. Exhaust from the secondary combustion chamber enters a heat exchange chamber wherein the heat content of the exhaust gas is transferred to the cooking surface of the stove. The burning rate of both the primary and secondary combustion can be independently controlled by individually selecting the air supplies to the combustion areas. An inclined grate, in combination with the direction of the exhaust gases, provides a self feeding feature in which an even burning rate of the fire is insured.

Abstract: Excess heat from a source such as a fireplace is absorbed into a liquid medium and transferred to storage for later use or to a distribution network for radiation at remote locations. The fireplace can be formed by heat conducting walls of a multi-chambered enclosure having an air guiding path for heating the air along with a liquid medium passing through the enclosure in a heat exchanger arrangement. The heated liquid medium can be stored and, when there is no combustion in the fireplace, returned to the fireplace enclosure for supplementary air heating. The liquid medium storage can include a tank having a pair of baffle plates in generally horizontal but diverging relation for producing heat layer stratification and separation of the liquid medium. Both cool and warm liquid medium are delivered between the baffle plates in proximity to the end of minimum vertical separation.

Abstract: A draft air combustion apparatus for directing substantially all of the draft air provided into a stove pipe for a stove upwardly into the stove pipe, and permitting a small amount of the draft air to flow downwardly into the stove to provide air to an area of combustion of the exhaust gases created by combustion in the stove in a region of the stove near the entrance to the stove pipe. The apparatus of the present invention including a plurality of vane elements located near the entrance of the draft flue to the stove pipe and being oriented parallel to each other and at an angle to direct the draft air upwardly.

Abstract: This invention pertains to a smoke collecting and exhausting system for a roaster boiler. The roaster includes a smoke exhaust passage provided therein so as to direct smoke from the roaster downwardly and to a smoke collecting and exhausting system. The smoke collecting and exhausting system includes a smoke collecting duct means which communicates with the smoke exhaust passage for collecting smoke from the roaster. The smoke collecting and exhausting system also has filter provided in the smoke collecting duct for removing oil particles from the smoke. A smoke drawing device is provided at a location away from the roaster and is connected to the smoke collecting duct downstream of the roaster.

Abstract: An energy collector and transferring apparatus which in its first embodiment utilizes three connected closed loop conduit systems. The first closed loop conduit system is to include an energy collector which is to collect not only solar energy but ambient energy. The energy is absorbed within a black liquid flowing through the first conduit system. The first conduit system includes a first energy exchanger wherein the absorbed energy is transferred from black liquid to a second energy absorbing medium. The second energy absorbing medium is cycled within a second closed loop conduit system. A compressor is included within the second closed loop conduit system to condense this medium from a gaseous state to a higher density fluid, thereby substantially raising the temperature. The energy from the second energy absorbing medium is then to be absorbed through an energy exchanger to a third energy absorbing medium of a third closed loop conduit system.

Abstract: An improved sun-tracking solar energy collector in constant focal communication with the rays of the sun during daylight hours and in which the moving element is made compact and inexpensive by incorporating therein only the function of receiving and redirecting the rays of the sun.

Abstract: Solar collectors have flat plate-like foil tubes with permeable interlayers with lattice structure surfaces bonded to the foils of the tube. Several tubes with insulating backing are seam bonded together to form a sheet for covering a roof. Heat transfer medium flows from inlets into a space along one side of the tube, through the permeable interlayer into a space along the other side of the tube and through an outlet. The structure is thin, light, inexpensive and easy to install. Flow of medium which covers substantially all of a surface may be precisely controlled. Temperature of medium in the collectors may be maintained only slightly higher than temperatures throughout the system.

Abstract: A heat pipe solar collector comprises an evacuated transparent envelope spaced from and surrounding the evaporation zone and a protective jacket spaced from and surrounding the condensation zone. The protective jacket is connected to the transparent envelope to protect the joint between the transparent envelope and the heat pipe against damage and is provided with openings for the passage of a heat-absorbing medium.

Abstract: Brain wave patterns associated with relaxed and meditative states in a subject are gradually induced without deleterious chemical or neurological side effects. A white noise generator (11) has the spectral noise density of its output signal modulated in a manner similar to the brain wave patterns by a switching transistor (18) within a spectrum modulator (12). The modulated white noise signal is amplified by output amplifier (13) and converted to an audio signal by acoustic transducer (14). Ramp generator (16) gradually increases the voltage received by and resultant output frequency of voltage controlled oscillator (17) whereby switching transistor (18) periodically shunts the high frequency components of the white noise signal to ground.

Abstract: A method and device for pressurizing the flow of venous blood in the portal vein to a diseased liver. The method comprises introducing arterial blood into the flow path of the venous blood in the portal vein. The device comprises an elongate chamber, the ends of which are adapted to be connected to the ends of the portal vein from which a section has been removed to provide a substitute flow path for the removed section, interiorly thereof a nozzle facing in the direction of flow and a conductor, one end of which is connected to the nozzle and the other end of which is connected to an arterial vein.

Abstract: A method of removing an article from an enclosure member providing an environment isolated from the ambient environment is particularly applicable in removing infected hospital materials from isolator enclosure members for isolating human patients with acute infectious diseases. Present methods do not satisfactorily prevent spread of infection from the removed material and maintain the integrity of the isolator. In one arrangement of the invention a disposal bag 21 sealed around a port 25 contains a closure bag 28 having a rigid hoop 30 across the disposal bag 21. Heat sealer 33 cuts and seals around the hoop leaving part of closure bag 28 closing the disposal bag 21 and part of bag 28 closing transfer port 25. In another arrangement closure bag 28 slides over a rigid former 34 extending outwardly from the transfer port and cutter sealer 33' cuts and seals portions of the closure bag across the disposal bag by cooperating with a backing member 29' in the closure bag 28.

Abstract: An otoscope comprises a guide tube which is to be inserted into the external auditory meatus of a patient and a side-viewing microscope which is reciprocated through the guide tube. A light beam direction-diverting device is provided in the distal end section of the guide tube. Where the microscope is in a retracted position, the light beam direction-diverting device faces an illumination window and observation window in the lateral wall of the distal end section of the microscope to divert light beams emitted from the illumination window ahead of the microscope in its axial direction and light beams conducted to the guide tube along the microscope toward the observation window. The microscope protrudes from the proximal end of the guide tube. When, therefore, the proximal end of the microscope is pushed into the guide tube, the distal end of the microscope protrudes from the distal end of the guide tube. A microscope-actuating device is provided between the guide tube and microscope.

Abstract: An implant useful for the surgical construction of a penis comprises an elongated member having a pair of stems at the proximal end for anchoring the member in the pubic area of a patient, and a trunk with a urethra receiving and supporting groove and an open distal end. In the preferred embodiment, the implant is made completely of silicone elastomer. A method of constructing a penis using the implant is also described.

Abstract: A pair of guide blocks are movable along an arcuate track of a substantially constant radius and each defines at least one rectilinear pin opening therethrough which extends parallel to the radius of the arcuate track for receiving rectilinear alignment pins therethrough. A scale extends along the arcuate track which indicates the angle of orientation of the pins with respect to each other. A first pin is inserted into a bone, a pin opening of one of the guide blocks is inserted about the protruding end of the first pin, and a second pin is inserted through the pin opening of the other guide block and then into the bone at an angle with respect to the first pin which corresponds to the angle indicated on the arcuate track. After the pins have been inserted into the bone, the osteotomy guide is removed from the pins, the bone is severed, and the bone segments are adjusted until the protruding ends of the pins are in alignment with each other.

Abstract: A composition and method for use with peritoneal dialysis patients for preventing or treating dialysis induced peritonitis. The method utilizes a flush solution of normal saline to prepare the peritoneal cavity for infusion of a dilute iodine solution which operates to kill pathogenic organisms contained therein. The dilute iodine solution has a combination I.sub.2 and HIO concentration in the approximate range of 0.1 ppm to 15 ppm and requires residence time of less than five minutes to provide an effective kill. The serial application of flush and dilute iodine solutions may be applied as part of a regular peritoneal dialysis program to prevent peritonitis or may be used with greater frequency as treatment for existing dialysis induced peritonitis.

Abstract: An I.V. administration set is provided with a flexible expansion section so as to accommodate an additional volume of liquid without the use of excessive lengths of tubing. The expansion section is in the form of pleated or corrugated tubing which, upon the introduction of liquid into an I.V. set such as by means of a hypodermic syringe, will accommodate an additional portion of liquid which is known in the I.V. administration art as a retrograde volume.

Abstract: A needle cannula comprises a hollow tubular member having a first portion and a second portion terminating in a sharp point. The outside diameter of the second portion is less than the outside diameter of the first portion, while the inside diameter of the second portion is not less than the inside diameter of the first portion.

Abstract: In an irrigation device, irrigation fluid flows from a reservoir 12 via an inflow passage 11 to a bladder 22 and out through an outflow passage 15 to a collection bag 17. Debris such as blood clots which tend to form at inlet 23 is disturbed and removed by manipulation of the balloon 18 using a procedure of closing and opening clips at P, Q and R in sequence.

Abstract: A catamenial tampon having a hollow core opening onto its insert end and having radial slots at said end in communication with the hollow core; the invention also relates to the method of tampon fabrication and to a tool used in such fabrication.

Abstract: A tampon having a series of parallelly aligned fibers is fused to a withdrawal string positioned transversely near one end of the fibers. The aligned fibers are then rolled in a jelly roll configuration in a manner which allows the free end of the withdrawal string to be centrally positioned at the bottom of the tampon at the inner end of the jelly roll.

Abstract: A tampon having an absorbent matrix with a superabsorbent material as a core is provided. The superabsorbent material is at least partially surrounded by a water dispersible coating and both the core and coating are surrounded by nonsuperabsorbent absorbents.

Abstract: A catheter having a shaft carrying an inflatable retention means such as a Foley indwelling or retention catheter or an endotracheal tube is provided with a retention balloon or bulb comprising thermoplastic elastomer in the form of a sleeve or collar having its margins bonded to the outer surface of the shaft which maintains its inflation and its retention capability for an extended period of time. When the catheter shaft is made of thermoplastic elastomer, the balloon can be heat sealed to the shaft. A one-piece connector including drainage fitting, inflation side arm and safety signal balloon can be bonded to the proximal end of the shaft.

Abstract: A solarium, especially for medical purposes, having one or more fluorescent tubes mounted in a frame, wherein the frame is constructed as part of a piece of residential furniture, such as a bed, a couch, a seat, a commode, a cabinet, a stand, a lamp, a television set and the like. The fluorescent tubes are disposed in reflectors which are open to an irradiation side of the frame. The fluorescent tubes are mounted under a covering which is permeable to ultraviolet rays. The covering provides a concave longitudinal trough adapted to fit the body of the user. Preferably, at least one solarium lamp is positioned at a distance above the cover so that the user can be irradiated simultaneously on both sides of his body. The solarium may be constructed as a mirror part of a hair dressing cabinet commode. In another embodiment, the fluorescent tubes are bent into a circle, where tubes of different diameters are arranged concentrically to one another.

Abstract: A novel portable cushion for selectively heating and supporting portions of a persons back while sitting or while riding in a car is disclosed, for therapeutic purposes and for comfort.

Abstract: A therapeutic device comprising, a sleeve for covering a portion of a patient's body and having flexible walls defining an inner space to receive liquid, a conduit system connected to the space, and a device for circulating a liquid through the conduit system and the sleeve space. The therapeutic device has a device for changing the temperature of the circulating liquid in the conduit system, and a device for pressurizing the liquid in the sleeve space.

Abstract: A pacemaker assembly having a ventricular inhibited pacemaker unit set to produce a signal for application to a patient's heart at a first rate of time and a ventricular triggered pacemaker unit set to produce a signal for application to a patient's heart at a second rate of time lower than said first rate of time, both units being contained within a housing and being independently operative with respect to one another.

Abstract: A maternity-nursing brassiere has a frame supported by two shoulder straps linked therewith through a pair of connector plates of resilient plastic material each having an upper eye engaged by a loop of the respective shoulder strap and a lower eye engaged by a loop of a corresponding frame strap. Two cups on the frame have upper flaps terminating in a pair of tapes each looped through an eye of a respective latch plate which is insertable between two mounting lugs rising from the associated connector plate, these lugs being wedge-shaped to form a downwardly converging gap between them.

Abstract: A novel apparatus and method for suppressing unwanted resonance in an electromanometry system. The apparatus includes a compliant air cavity connected through a variable impedance device which is coupled in parallel to the liquid-filled catheter of the electromanometry system. By varying the hydraulic impedance through which the compliant air cavity is coupled to the system, precise impedance matching capability is provided over a wide range of hydraulic impedance values, thereby permitting suppression of unwanted resonance and improved frequency response of recorded waveforms in a wide variety of catheter-transducer systems.

Abstract: A urine specimen collector assembly includes a specimen tube and funnel-shaped member wherein the specimen tube is characterized by having a lower reinforced reservoir tip of reduced diameter so that the tube is adapted for use with centrifuge machines for the precipitation of a measured quantity of solid materials in the tip from the specimen placed in the tube. The mouth of the tube is outwardly flared to conform to the shape of the outlet end of the funnel, and the funnel has a ribbed internal surface to direct the flow of liquid through an elongated outlet tip for insertion into the specimen tube so that the tube and funnel may be filled with fluid. Upon inversion, a user may empty all but a measured quantity of fluid from the tube.

Abstract: A disposable device for cleaning teeth is composed of a flexible, soft honeycombed sheet. Bristles composed of integral fibers extend outward from the exposed surface of the sheet. The sheet is secured over the finger which is used for massage of the user's gums and cleaning of the user's teeth. In its preferred form, the sheet is impregnated with a dentifrice.

Abstract: A hair curling iron with retractable brushes having a handle, a generally tubular body secured at its one end to the handle and with a side wall containing a plurality of wall openings, a plurality of bars disposed longitudinally within the body with bristles extending in a generally radially outward direction for reciprocating movement through the wall openings, supports positioned substantially within the body toward each of its distal ends and beyond the bars for longitudinal movement with respect to the body, a plurality of actuator pins fixedly secured to each support and extending longitudinally inward toward the bars at a preselected angle relative to the bars for slidably engaging the bars and moving them in a similar generally radial direction in response to the movement of the supports in a similar longitudinal direction, and a tie rod slidably disposed within the body in longitudinal, coaxial alignment with the body and fixedly secured to the supports for causing their simultaneous longitudinal mov

Abstract: A valve, comprising: a cylindrical casing, closed at its ends by covers, and having axially aligned inlet and outlet chambers midway of its length disposed at right angles to the axis of the casing. Communication between said chambers is controlled by a ported, fluid pressure operated, movable valve plate assembly, including parallel cylinders, each containing a stationary piston connected to the inner end of a pair of axially aligned rods, or guides, fixed at their outer end to the covers. Each rod has a passageway communicating at its inner end with one end of its associated cylinder for supplying operating fluid thereto to bodily reciprocate the valve plate assembly on said rods within the casing. An adjustable collar positions a fixed wear plate in sealing engagement with one side of the valve plate assembly, and a fluid pressure actuated loading ring urges a floating wear plate into contact with the other side of said valve plate assembly.

Abstract: A valve for use with a liquid comprising: a valve casing having an inlet and outlet; a valve seat arranged between the inlet and outlet; a plug adapted to be received on the valve seat; sensor means adapted to sense the level of the liquid, the sensor means being operatively associated with the plug so as to vary the position of the plug relative to the valve seat as a function of the level of the liquid; and a lever adapted to vary the position of the plug relative to the valve seat independently of the sensor means.A valve, for use with a liquid, comprising: a valve casing having an inlet and outlet; a valve seat arranged between the inlet and outlet; a plug adapted to be received on the valve seat; and a lever adapted to vary the position of the plug relative to the valve seat by means of a stem attached to the lever. The lever is attached to the stem by means of a pin attached to the lever, the pin being fitted within a fusible bushing fitted within a hold in the stem.

Abstract: An oxygen regulator for controlling the flow of breathing oxygen and uncontaminated air at various altitudes includes a balanced oxygen valve (20) and a balanced air valve (50) which cooperate with a dilution aneroid valve (62) to provide breathable mixture whose oxygen percentage increases with altitude to a predetermined altitude. Above that altitude one hundred percent oxygen is provided. A gas loading aneroid valve (110) operates to increase the oxygen pressure in accordance with altitude over a range of altitude.

Abstract: A double piping type hydraulic pressure control device in which hydraulic pressure control of a hydraulic pressure channel A is transmitted to another channel B in such a manner that the hydraulic pressure to be exerted on a balance piston for hydraulic pressure control is obtained solely from the hydraulic pressures of the two output chambers while two input hydraulic pressures are arranged to have nothing to do with the control action.

Abstract: Disclosed is apparatus for dispersing water within a flowing stream of fuel oil, to produce an oil and water emulsion which improves combustion efficiency by as much as 15 percent. The apparatus includes a pressurized supply of water, a differential pressure regulator, a proportioning or tracking valve, and an emulsifying mixer. The differential pressure regulator provides water to the tracking valve at a pressure which is a constant amount above that of the oil just upstream of the mixing point. The tracking valve has two chambers. A first chamber receives oil and contains a float which moves in response to oil flow therethrough; a float extension penetrates from the first chamber into the second chamber which receives the water, and causes movement of a needle shaped element therein, to vary the water flow path area. The operative valve elements are coaligned and configured especially for responsiveness and accuracy in proportioning.

Abstract: A butterfly valve is disclosed for use in controlling the flow of gaseous fluid under high temperature, high pressure conditions. The interior of the valve body has non-overlapping semi circular valve seats spaced to either side of the shaft for the valve disc. The valve disc is rigid and inflexible throughout and, when closed, its periphery terminates close to the interior of the valve body under all operating temperatures. When the disc is closed, the semi-circular valve seats cooperate with the recessed rigid periphery of the disc to form a chamber chargeable with purging fluid at a higher pressure than the fluid on the upstream side of the valve and effective to prevent flow of the latter past the valve disc.