Abstract: A pneumatic condition sensing system for reducing the consumption of air supplied by a pneumatic source, the system having a bleed type pneumatic device for bleeding air from a branch line to atmosphere to control the pressure within the branch line in response to a sensed condition, an elongated restriction for connecting the bleed type device to the pneumatic source, the elongated restriction having an air conserving flow versus pressure relationship, and a controller connected to the branch line and responsive to the pressure therein for providing a control function usable in controlling a condition.

Abstract: A pneumatic servo assembly (20) is provided for an electro-pneumatic control system (10) having closed loop control of a D.C. motor (12) operated from an error signal (56) developed from an electrical set point signal (4) and a pneumatic feedback signal (44). The feedback signal (44) is made compatible by a pressure transducer (26) monitoring the pressure output signal (22) of the pneumatic servo assembly (20) and establishing an electrical signal indicative thereof which is scaled, zeroed, and amplified by an amplifier unit (46).

Abstract: Telescoping coil systems 14 and 16, respectively, engage a Z-shaped balance beam 12 at opposite arms 18 and 20 thereof said beam being mounted centrally by a flexural pivot suspension 10. A surface 26 is provided on the arm 18 and forms a nozzle and baffle plate system with nozzle 22. The torque caused by the pneumatic pressure acting on the surface of nozzle 22 is compensated for by a torque exerted by two telescoping coil systems 14 and 16 when an electrical current is passed through. Thereby the pressure at an output 28 is proportional to the electrical current. A flexural pivot suspension provided for the balance beam includes a pair of crossed baffle springs on each side of the balance beam. Each leaf spring has one end attached to the balance beam and the other end attached to a bearing portion.

Abstract: An electro-pneumatic transducer for converting an input current signal to a proportional output pressure signal is disclosed. The transducer includes housing means defining a chamber, the housing may be completely of magnetic material or may have a magnetic portion and a non-magnetic portion. The transducer includes an input communicating with the chamber for supplying a fluid under pressure thereto and having a valve seat with a nozzle opening therethrough, that portion of the nozzle forming the valve seat being formed of non-magnetic material while the remainder of the housing is of magnetic material or the valve seat may also be of magnetic material. The transducer also includes an output communicating with the inlet for allowing fluid supplied by the inlet to flow to a control device.Disposed within the chamber is a membrane means in operative association with the nozzle opening in the valve seat for varying the fluid flow through the nozzle opening to thereby vary the fluid pressure at the output.

Abstract: A valve construction including an impingement plate and a nozzle structure mounted for relative movement therebetween, a first conduit for conducting fluid to the nozzle structure, the nozzle structure consisting of a plurality of cylindrical nozzles at the end of the conduit proximate the plate for projecting fluid from the conduit onto the plate or into the conduit (for reverse flow applications), the plurality of cylindrical nozzles providing a greater ratio of total metering area to projected nozzle area than is obtained by a single cylindrical nozzle. As an alternate to the plurality of cylindrical nozzles, a shaped noncylindrical nozzle may be used which has a higher ratio of metering area to projected area than that of a single cylindrical nozzle.

Abstract: A vacuum regulator for automotive vehicles of the type having an engine exhaust system and a computer-controlled exhaust gas recirculation system, the regulator having a housing provided with a pair of spaced outlets intercommunicating through a flow restrictive orifice and adapted to be connected to the engine exhaust system and to the exhaust gas recirculation system, respectively; an inlet for atmospheric air connected by a passageway to the outlets; and a solenoid-operated spring-biased valve in the housing controlling flow of atmospheric air to the outlets; the housing being fashioned in two parts or sub-assemblies which are interconnected at final assembly by the flux collector which is part of the solenoid, the operating parts of the regulator being uniquely formed and arranged to minimize noise of operation, and the entire assembly being uniquely constructed to minimize cost of manufacture.

Abstract: In a device for converting electric signals into pneumatic signals, a soft-iron core (3) and a coil (2) are arranged stationary. The soft-iron core has an air gap (7) between two pole shoes (5, 6). A permanent magnet (8) is movably arranged within this gap (7) or directly in front of it. The permanent magnet can be fastened, for instance, to one lever arm of a rocker (9). The other lever arm of the rocker (9) is then developed as baffle plate (11) adapted to throttle the stream of air emerging from a pneumatic nozzle (12) to a greater or lesser extent depending on the position of the rocker. The dynamic pressure of this stream of air is fed via a booster (15) to an outlet (20).

Abstract: A fuel injection system is proposed which serves to adapt the fuel-air mixture as precisely as possible to operating conditions of the internal combustion engine. The fuel injection system includes metering valves, each of which is assigned a regulating valve whose movable valve element can be exposed on one side to the fuel pressure downstream of the respective metering valve and on the other side to a control pressure line defined on one end by a control pressure valve of the nozzle/impact plate type and on the other end by a control throttle. The control pressure valve has a permanent magnet and an electromagnet, the magnetic fluxes of which are guided via an armature in such a manner that in at least one air gap the magnetic fluxes of the permanent magnet and of the electromagnet extend in the same direction, while in at least one other air gap the magnetic fluxes of the permanent magnet and of the electromagnet extend in opposite directions.

Abstract: An optical hydraulic control wherein the flow of hydraulic fluid is controlled by movement of a valve spool 12. Movement of the valve spool is initiated by a hydraulic pressure differential that is established by moving a control member 34 out of an equilibrium position. Movement of the control member from its equilibrium position is accomplished by illumination of a beam support structure 36 with an optical command signal. The control member 34 is returned to its equilibrium position after appropriate movement of a valve spool 12 by mechanical linkage between control member 34 and valve spool 12 or, alternatively, by modulation of the optical command signal.

Abstract: A diaphragm operated valve assembly is controlled by an electromagnetic valve assembly. A flat disc armature, which forms part of a flux path, is operable in an inner chamber to modulate the flow between the inner chamber and an exit port in response to an applied magnetic force. The level of the effective magnetic force is a function of the armature mass, and the pressure acting on the disc surface. A pole piece adjacent to the flat disc armature is slidably adjustable to establish a specified force to actuate the armature to the closed or sealing position. This specified force is proportional to the current flow through the winding of the electromagnetic valve assembly. Thus the armature operates to seal communication between the inner chamber and the exit port at a given pressure differential as a function of current flow. The travel distance between the armature and a nonmagnetic seal seat has been minimized by spring biasing the armature in proximity to the seal seat.

Abstract: A flapper-poppet (new) that differs from a flapper-nozzle (old) in that the flapper-nozzle is a second stage operator that employs an amplifier which operates on de-amplified pressure. Although both the flapper-poppet and the flapper-nozzle are controlled by a conventional torque motor, the flapper-poppet is a first stage operator which operates on high supply pressure.

Abstract: A temperature compensation circuit is provided which can be used for span temperature compensation in an electropneumatic transducer system and which includes a constant current generator circuit coupled to a bridge of piezo resistances in a pressure transducer to supply a constant current through one piezo resistance of the bridge to common. The Electropneumatic Transducer System includes a zeroing circuit, a voltage chopping circuit, a linearity correction circuit, a low-current shut-off circuit, and a high-current shut-off circuit to provide hard turn-ons and hard turn offs of the system at the lower and upper ends of the pressure output range or span. The Electropneumatic Transducer System also includes a voltage railsplitting circuit arrangement to minimize the operating currents, and voltages. With these features, the Electropneumatic Transducer System is particularly adapted for use in hazzardous combustible atmospheres where Intrinsic Saftey and accuracy are required.

Abstract: A normally closed line pressure regulator valve has an orifice that is opened and closed as the coil of the solenoid is energized and deenergized. When the valve is opened, the pump outlet is opened to a vent port. A line pressure relief valve in parallel with the solenoid valve opens at a predetermined pressure when the solenoid valve is closed and establishes a maximum line pressure. Minimum line pressure is determined by the pressure drops across orifices located between the outlet of the pump and the vent port. Line pressure is regulated between the maximum and minimum values by energizing and deenergizing the solenoid coil.

Abstract: An electric to pneumatic transducer that utilizes an electrical coil and a magnet assemble that is suspended by a plurality of springs. The magnet assembly acts upon a nozzle assembly in such a manner that movement of the magnet assembly causes a change in the release of pneumatic fluid from the nozzle assembly. The movement of the magnet assembly is accomplished by increasing or decreasing the electrical current that passes through the electrical coil with a corresponding increase in pressure or decrease in pressure exerted by the magnet assembly upon the nozzle assembly. The unique configuration of the springs also allows free up and downward vertical movement of the magnetic assembly and restricts or prevents sideward movement of the magnet assembly.

Abstract: A pressure control valve with an impact plate which serves as a regulator for a specific drop in pressure. The pressure control valve includes an armature disposed in an electromagnetic field established by an electromagnetic coil and a permanent magnetic field, with the armature being rotatably supported between two respective pole shoes located on each side of the armature. The pole shoes located on one side of the armature, in contrast to the pole shoes located on the other side, have an opposing magnetic polarity induced by the permanent magnet. The pole shoes which are not aligned opposite one another on armature 85, are approached by armature 85 with movement of the impact plate toward a valve seat, and causes an increase in the air gap planes facing the armature, as compared to the other two pole shoes, and thereby establishes a non-linear characteristic for the pressure control valve.

Abstract: An apparatus for maintaining a relatively moist ambient gas in intimate contact with a humidity sensing element includes a control nozzle for flowing relatively dry pneumatic control gas therethrough. The nozzle is adapted to be modulated for controlling the humidity within a space. A rigid control cone is coupled to the nozzle for defining a cavity therebetween and having a fixed volume. The cone includes a pin member which is movable with respect to the cone for effecting nozzle modulation. A discharge spigot is disposed in fluid flow communication with the cavity, the spigot being arranged for exhausting the pneumatic control gas to a region remote from the humidity sensing element.

Abstract: An electro-hydraulic control structure having a control input positioning a flapper relative to a nozzle to generate a control output pressure is provided with a squeeze film damper which utilizes the flapper, or an extension thereof, as the movable element of the squeeze film damper. Preferably the flapper is pivoted and forms with the nozzle exhaust passageway a tapered gap receiving a small portion of the nozzle flow which acts as the damping fluid. The majority of the nozzle flow passes through a hollow portion of the flapper located downstream of the nozzle.

Abstract: An apparatus is disclosed for adjusting an output pressure signal from a pneumatic device to a selected pressure for a given input pressure signal, the apparatus having a pneumatic device for receiving an input pressure signal and for providing an output pressure signal as a function of the input pressure signal, and a mounting apparatus for tiltably mounting the pneumatic device to a support to adjust the output pressure signal in response to selectively tilting the pneumatic device so that a given output pressure signal can be selected for a given input pressure signal.

Abstract: In a VAV terminal local control loop including a bellows controlled orifice in which the bellows inflation is controlled by a bleed thermostat, a signal is produced indicative of terminal satisfaction/dissatisfaction which can be used in controlling the air handler. Specifically, the position of the opening in the bleed plate is detected and compared with the position of the bleed plate permitting the maximum amount of conditional air to be supplied by the terminal to the zone. A signal indicating whether or not the bleed plate is in the maximum bleed position is generated which can be used to furnish information for controlling the air handler.

Abstract: A variable output nozzle for permitting the output of air or gas from the nozzle to be varied. The variable output nozzle includes a nozzle housing having a bore located therein, a spherical ball located within the bore for reciprocal movement within the bore and an aperture in the nozzle housing for supplying pressurized air or gas to the bore in the nozzle housing. A plurality of slots are also located in the nozzle housing and extend into the upper portion of the bore and the bottoms of at least some of these slots are located at different depths so that the volume of pressurized air or gas exiting the nozzle will vary as the spherical ball passes the bottoms of the slots. The variable output nozzle is particularly useful as a pneumatic pressure transducer nozzle.

Abstract: An electro-pneumatic signal converter for converting an electrical current signal into a pneumatic pressure, comprising a force balancing system where a magnetic force is balanced against a pneumatic force, consists of a coil (11) through which the electrical signal current flows, a magnetic circuit comprising a core (12) of ferromagnetic material disposed in the coil (11) with a nozzle chamber (14) with a mouth in the form of a nozzle (13) in one end of the core, a flapper (17) of ferromagnetic material over the nozzle and a link (16) of ferromagnetic material which closes the magnetic circuit between the flapper and the opposite end of the core, a feed line (19, 19A, 19B) for a constant flow of feed air into the nozzle chamber (14) and out again through the nozzle (13) into the gap (25) between the nozzle and the flapper, and a pressure-sensing line (24) from the nozzle chamber to a pressure-dependent member (7) to transmit a pneumatic pressure signal from the nozzle chamber to the pressure-dependent member

Abstract: A fluid flow control device comprises first second, and third fluid pathways. The first and second pathways are adapted for communication with separate sources of pressurized fluid. The third pathway is coupled in flow communication with the first pathway and includes a flexible wall which forms an interface with a portion of the second pathway. The flexible wall meters the flow communication between the first and third pathways in response to fluid pressure fluctuations in the second pathway. The fluid pressure in the first pathway is thereby elevated until substantial equilibrium with the fluid pressure in the second pathway occurs, and is thereafter continuously adjusted in response to subsequent fluctuations of fluid pressure in the second pathway to maintain this condition of substantial equilibrium.

Abstract: A damping system, more specially, for measuring and automatic control systems takes the form of mass of damping liquid placed between two parts which may be moved in relation to each other and which are to be damped. By the selection of the damping liquid, as for example a silicone oil, and of the form and size of the space between the two moving parts and, furthermore, of the properties of the two parts touched by the liquid, it is possible to make certain that the liquid is kept in place by surface tension effects, that is to say because of its own surface tension and the surface tension properties of the lining faces touched by it.The damping unit may take the form of two, more specially frusto-conical plates, able to be moved in relation to each other and of which one may undergo adjustment by using a threaded rod and a lock nut.

Abstract: A controller for a damper maintains a substantially constant volumetric rate of flow of air through a duct into a controlled space for a given condition in the space and resets the rate of flow to three different levels as a function of three different conditions in the space. Two pneumatic actuators respond to the four conditions in the space and produce forces which vary with the conditions. A floating lever receives the forces and causes the controller to set the air flow as a function of the sum of the weighted values of the forces produced by the two actuators.

Abstract: The invention relates to a device for producing a control pressure which corresponds to a rotary speed imparted to a shaft of a pump which is a part of the device. The device includes a measuring orifice formed by a fixed throttle and a control orifice formed by piston arrangement operating as a controlled throttle. The controlled throttle is responsive to oppositely acting pressures from opposite sides of the fixed throttle. The controlled throttle is in series with a fixed discharge throttle and the control pressure is tapped from between the controlled throttle and the discharge throttle.

Abstract: A nozzle flapper valve provided with a nozzle, fixed throttle and flapper, characterized in that the flapper is formed to be cylindrical and has the cylindrical peripheral surface positioned on the axis of the nozzle so as to simplify the flapper moving mechanism and to prevent the flapper clearance from being clogged with dust in the fluid.

Abstract: A fluid actuated pilot assembly employing a cantilevered spring member which is mounted to apply a force to a sensing piston in opposition to the force applied by the sensed fluid pressure. Upon the occurrence of the pressure of the fluid being sensed exceeding the force of the cantilevered spring member, the sensing piston is moved to initiate a control function.

Abstract: A pilot stage for use in pilot pressure control applications includes a magnetic torque motor having an output torque in response to an input current, a flapper operated by the magnetic torque motor and responsive to the output torque, the magnetic torque motor being arranged to apply a resultant spring rate to the flapper, and first and second nozzles responsive to the output torque applied to the flapper for providing a differential output pressure proportional to input current, the first and second nozzles having a size sufficiently large to swamp out the resultant spring rate applied to the flapper so that the first and second nozzles apply a feedback force to the flapper sufficient by itself to substantially balance motor torque.

Abstract: A flapper valve having a negative rate characteristic is variably opened by an external force and controls fluid pressure to a piston which moves, in response to this pressure, in order to return the valve to a null position. A positive rate flapper valve applies force to the negative rate flapper valve and balances the fluid pressure in the negative rate flapper valve, thus providing high sensitivity negative flapper valve operation in the null position region and a negative rate in the region to overcome piston friction, without instability.

Abstract: A motor-nozzle coupling member for coupling a motor to a nozzle in an electro-hydraulic control structure wherein a linear electric motor having an armature is located at a fixed distance relative to the nozzle by a coupler which engages the motor and nozzle and extends therebetween to establish the spacing between the motor and nozzle and with the coupler being deformable after initial assembly to set the desired spacing.

Abstract: A totally pneumatic crane warning system is disclosed capable of use in oil well environments. The crane warning system utilizes a pneumatic function generator. The pneumatic function generator includes a means for receiving a linear pneumatic signal that may be representative of a boom angle and translating that signal to a non-linear output representative of the maximum load capacity of the crane at that angle. This function is accomplished through the use of a rolling cam machined to represent the functional relationship between the boom angle and the maximum load capacity at that angle. This relationship has been found to be non-linear in nature. A pneumatic control circuit is utilized in conjunction with the rolling cam to effect the pneumatic output signal that is representative of the maximum load capacity at a given boom angle.

Abstract: A pneumatic converter comprising a bellows having in its interior a coupling plate connecting the two ends of the bellows together at a position offset from the center axis of the bellows.

Abstract: A valve, notably for use as a demand valve in breathing apparatus, has a pressure-responsive diaphragm coupled to a separate control member which lies in the path of a jet of gas which vents from a control chamber through an orifice, gas being continuously supplied to the control chamber. Deflection of the diaphragm in response to pressure changes in a second chamber caused by inhalation and exhalation of the user of the apparatus pivots the control member towards or away from the jet orifice to control the rate of venting from the control chamber and thereby vary the pressure within the control chamber. Flow of gas through the valve to the user of the apparatus is controlled by a flexible disc which in turn responds to the pressure in the control chamber. By employing a separate diaphragm and control member the former can be optimized for pressure-response while the latter can be optimized for valve-regulation by interaction with the gas jet from the control chamber.

Abstract: A thermostat for a pneumatic control system controls output pressures to a plurality of elements to be controlled. The thermostat can control output pressure directly or inversely and linearly or nonlinearly with respect to temperature. Additionally, the pressures can be controlled sequentially or simultaneously.

Abstract: A fluid signal comparator includes a flexible diaphragm clamped within a housing and defining a signal input chamber coupled to a signal source and an input/output chamber connected to an air supply and to a load. A leakport orifice unit includes a centrally located nozzle having a planar outer edge seat located in spaced parallel relation to the diaphragm. The diaphragm moves to create a pressure in the input/output chamber which balances the input signal force on the diaphragm. An output port is connected to the input/output chamber and to the load in the illustrated embodiment to transmit the pressure and/or flow to the load. The pressure of the input signal and of the stream acts on opposite sides of the diaphragm and positions the diaphragm relative to the orifice seat to create a restricted flow passageway having the necessary pressure drop to create a balanced pressure condition in the output chamber.

Abstract: For use in an agricultural machine which is automatically steered by sensing along a row of plants, a component of the automatic steering system, namely, a comparator system is disclosed herein which utilizes hydraulic signals from independent sensors and mechanically compares such signals with each other and with a mechanical feedback responsive to the degree of angularity of the steered wheels of the vehicle. The net result of the combination and construction of the comparator system is to provide automatic steering control for a small variation of steering of left and right steering courses, for example 2 to 5 degrees, wherein any large amount of deflection of the steering wheels that may be caused by the vehicle operator taking over the steering function will not affect the automatic operation of the comparator mechanism nor will the comparator mechanism have any response thereto.

Abstract: There is disclosed herein a negative pressure dialysis machine which includes a negative pressure valving system and transmembrane pressure alarm system.An electromagnetically controlled flapper valve is disclosed herein for use as a negative pressure control valve. The flapper valve permits accurate control of negative pressure and changes in negative pressure to be affected rapidly.Transmembrane pressure alarm systems are provided which detect the difference in pressure between the blood and dialysate in the dialyzer and activate alarms and prevent dialysis (a) if the dialysate pressure exceeds the blood pressure and/or (b) if a blood pressure signal is not received which would permit actual transmembrane pressure to increase beyond a predetermined limit.

Abstract: A temperature dependent electronic control switch, especially suited for an automatic temperature control in vehicles, including one or more NTC resistors as sensors in a bridge circuit, an amplifier, to amplify the signals from the sensors, a solenoid for producing a variable magnetic field from signals received by the amplifier, an iron strip, an air nozzle connected to a vacuum, a servomotor connected between the air nozzle and the vacuum, and a control flap. The iron strip, moving in response to the magnetic field from the solenoid, obstructs an opening in the air nozzle, thereby changing the pressure felt by the servomotor and thereby causing the control flap of an air-conditioner or heater to move in a predetermined manner to mix air of different temperatures.

Abstract: A fluid control valve, especially intended as a pilot valve in pneumatic control systems, in which the controlled flow path is provided by the gaps between adjacent coils of a helical spring. The flow direction is from the outside to the inside of the spring; this allows the valve to seal against high pressures, since the spring will be helped to remain closed by the pressure forces acting thereon.

Abstract: A fluid pressure gauge type pressure responsive gauge drive having a drive to a sensor controller system with sensor controllers actuatingly engaged at respective adjusted pressure limits with gauge movement travel unimpeded by sensor controller contact in the range of movement between sensor controller pressure limit position settings. The drive may be connected to drive a fluid pressure gauge needle over an indicating dial and upper and lower pressure limit setting needles are adjustable to desired settings over the indicating dial. Calibration structures are provided for a coordinated setting of the gauge dial drive and in the drive of the sensor controller system calibrating each gauge structure for the "C" type bourdon tube installed.

Abstract: A pneumatic control instrument includes a nozzle-flapper system having improved dynamic response characteristics under vibrational conditions. A light-mass, compliant flapper having a high natural frequency covers the nozzle and serves to cushion the impact of the nozzle striking the flapper by moving at the same amplitude of vibration as the nozzle so as to precisely track the nozzle over a wide range of vibrational frequencies and amplitudes.

Abstract: This invention relates to timing devices for pneumatic signals, of the kind comprising a pneumatic motor having gearing which is brought into coupled engagement with a timer when an input signal occurs so that a control member associated with the timer, which can be set for a desired delay between the input signal and an output signal, is moved from an initial position which determines the length of delay to a terminal position which marks the end of the delay and at which the output signal is produced.

Abstract: A pneumatic control valve of the flapper type for controlling the resultant pneumatic pressure within a chamber from two sources of pressure in proportion to an electrical control signal is disclosed, wherein two flappers, one associated with a nozzle connected with one of said sources and the other associated with a nozzle connected with the other thereof, are resiliently coupled to a common electrically actuated armature such that at least at extreme controlled pressure rates, the resilient coupling permits one flapper to close its nozzle while permitting the other to continue to control the pressure rate from the other nozzle whereby to permit reducing the flapper-nozzle gap and to enlarge the nozzle area resulting in a very high valve gain and at the same time reducing quiescent pneumatic mass flow and increasing the transient pneumatic mass flow capability through said valve.

Abstract: A pneumatic control device for operating pneumatic apparatus in a pneumatic control system. The control device includes a pneumatic conduit having a bleed orifice therein, one end of the conduit being adapted to accommodate an air pressure source, a venting member for regulating the flow of air through the bleed orifice, the venting member being movable between a first position in which the flow of air through the orifice is unimpeded by the venting member and a second position in which substantially no air will flow through the orifice, a timing means activatable for a variable but predetermined time period which time period is selectable at the outset of activation, and a control means connected to the timing means and to the venting member for controlling the movement of the venting member between the first and second positions upon the activation and deactivation of the timing means.

Abstract: A fluid flow control valve, particularly for use in a gas turbine engine fuel control system has an orifice with a closure member which is urged open by a pressure signal and which is urged shut by a biasing spring. The bias applied by the spring is variable by an input control lever and the response of the spring bias variation to lever movement is itself adjustable.

Abstract: A fluidic device having a sensing nozzle remotely mounted from an emitter assembly and communicating with it through a connecting tube. An adjustable nozzle assembly, located within the emitter assembly, is movable with respect to an outlet and aligned orifice to provide a zero level output signal from the outlet for various lengths of connecting tube. The nozzle assembly is also adjustable to provide a range independent zero level output signal for different pressure level sensitivities. A test jack communicates with the outlet to monitor the output signal and provide for adjusting the zero level output signal.

Abstract: A fluid pressure transducer device including first fluid pressure responsive means and second fluid pressure responsive means which together define a sealed volume of fluid. The first fluid pressure responsive means is exposed to first and second input fluid pressures and responsive to variations in one or both thereof to vary the volume of the sealed volume as a function of the first input fluid pressure modified by the pressure ratio of the second input fluid pressure to the first input fluid pressure. The second fluid pressure responsive means is responsive to the changes in the sealed volume of fluid and produces an output force signal in response thereto. There may be provided a variable volume chamber containing a temperature responsive element vented to the sealed volume of fluid to cause an increase or decrease in the sealed volume to compensate for temperature variations of the sealed volume of fluid.

Abstract: An electrically-controlled, hydraulically-actuated valve, having an inlet joined to a main outlet through a pressure regulating chamber; a by-pass passage joined to the pressure regulating chamber through a second enlarged chamber coaxial with the first; a valve seat formed at the juncture of the two chambers; a slidable valve, having one end tapered to seat in the valve seat and coaxially passing through the second chamber; a flow restricting viscosity non-influenced orifice in the inlet passage to form a jet of the introduced fluid; a blind hole extending into the body of the valve from the first chamber, directly opposite the discharge end of the inlet passage and coaxial therewith to avoid any jet stream impulse force on the tapered piston; a magnetizable core mounted on the other end of the valve; an annular electrical coil surrounding the core; and a biasing valve mounted in the discharge end of the by-pass passage and spring-biased against the flow of fluid.

Abstract: A pneumatic amplifier is disclosed having a body, the body with two opposed heads, a sensor head, and a valve head. An air direction chamber is defined interiorly of the two heads and body, and is separated from the sensing chamber by means of a sealed piston. The piston is actuated at one side by means of back pressure on a jet orifice which is connected to a sensor supply, and the back pressure is translated into a movement of the flexible piston. In the valve chamber, a dart valve is actuated on one end by the piston, and its cone at the other end seats in a valve seat in pneumatic connection with the valve head. The valve head has a signal supply which, when not by-passed through the dart and its associated valve, passes out through a signal tube to actuate a signal device, whether ultimately pneumatic, electric, hydraulic, or other source of power. Optionally a diaphragm type piston is employed.

Abstract: An electromagnet is mounted on a ferromagnetic support member. A ferromagnetic flapper valve element arranged to control fluid flow from a nozzle orifice is movably mounted on the ferromagnetic support member and controllably moved by the electromagnet. The electromagnet, the support member and the valve element form a substantially closed magnetic circuit with an air gap being provided between the electromagnet and the valve element. Ferromagnetic and paramagnetic spacers are disposed between the electromagnet and the support member. The air gap between the electromagnet and the valve element is determined by the combined thickness of the spacers and another gap in the magnetic circuit is determined by the thickness of the paramagnetic spacer.