Abstract: A differential pressure responsive switch utilizes an operating diaphragm which has a position controlled by a pressure being monitored with the diaphragm acting through a transmission member upon an electrical switch and includes a first chamber divided by a control diaphragm and having an inlet for the pressure to be monitored to one side of the control diaphragm while the other side of the control diaphragm carries a closure member for an adjacent bleed valve seat. An inlet for the bleed valve is connected via a throttle to a source of a pressurized gas and to a second chamber defined by the operating diaphragm and a spring is engaged through the transmission member to urge the operating diaphragm against the pressure in the second chamber.

Abstract: An over-temperature control for a thermostat uses an electrical contact actuator of a memory metal having an ability to change its physical configuration at a transition temperature to a "memory" shape. The contact actuator is arranged to bear against a cantilevered leaf spring having electrical contacts at a free end of the spring while the other fixed end of the spring is connected to complete an electrical circuit through the spring. The spring is also actuated by a bi-metallic element to produce a normal temperature responsive operation of the thermostat. The memory material actuator is arranged to provide a flexing of the spring cantilever to move the free end contact between a first and a second electrical terminal when the memory material is exposed to a transition temperature allowing the actuator to assume its "memory" shape.

Abstract: An electro-pneumatic pressure converter including a switching valve having at least one plate-like piezoelectric element, which is supported at one end in a cantilever manner inside a sealed chamber and a distal end portion of which moves upon application of a voltage, at least two pressure nozzles which are opened and closed upon displacement of the piezoelectric element, and an output channel extending from the sealed chamber to an external portion; a pilot relay for converting a pneumatic pressure signal from the output channel into a pneumatic pressure signal; a pressure sensor for converting the output pressure signal of the pilot relay into an electrical signal; pulse width modulating means for supplying a pulse-width modulation signal corresponding to a difference between the electrical signal from the pressure sensor and an external input signal to the plate-like piezoelectric element of the switching valve; a power supplycircuit for obtaining a predetermined voltage from the external input voltage to

Abstract: A control method uses a room thermostat for generating an output signal representative of an energy demand and an energy source which can be cyclically switched on and off and includes the steps of determining within a switching cycle of the energy source the actual switch on period, comparing the actual switch on period with an adjustable desired switch on period within the cycle to produce a control signal representative of the energy demand and controlling the energy source in accordance with the control signal.

Abstract: A method for producing sinusoidal waves uses the steps of generating a plurality of clock signals during a 2.pi. period, using the clock signals to control the generation of 2.pi. periodical square wave pulses having preselected length and phase relationships during respective ones of the clock signals and applying the square wave pulses to a low pass filter. The reduction of pulse length as well as the phase relationship of the pulses is evaluated from a system of equations by setting the odd harmonics of corresponding Fourier series to zero or to a predetermined minimum value. A circuit device utilizing this method uses a switching amplifier operated in a binary sequence having a period corresponding to the desired sine wave period and a low pass filter connected to the output of the amplifier.

Abstract: An electromagnetic valve uses a solenoid coil to produce a magnetic attraction of a cylindrical shell core against the action of a spring. A valve seat is constituted by a plate of a hard material arranged to cooperate with a circular ridge on an end of the core to obtain an hermetic seal therebetween. The plate is maintained against a bearing surface within a valve housing by a telescoping element located within the shell core and providing a sliding support surface for the shell core.

Abstract: An explosion-proof type electro-displacement converter device comprising a cylindrical first yoke attached through a permanent magnet which is at the center of the bottom of a bowl-shaped second yoke, an exciter coil winding supported elastically by springs and arranged in the magnetic path formed between the yokes, the opening of the bowl-shaped yoke is sealed by a sealing means, and an output stem linked with the exciter coil winding and projecting, leaving an explosion-proof gap, through an opening which penetrates through the bowl-shaped yoke or the sealing means.

Abstract: A float stabilized constant current source uses a floated cylinder with a rotational signal output generator and two torque generators for applying a linear torque and an opposing current squared torque to the floated cylinder, respectively. The current squared torque is balanced against the linear torque by a servo system applying a current to the torque generators in series to create a point of zero net torque on the floated cylinder. The current is obtained from the signal generator representative of a cylinder rotation and is used as a stabilized constant output current, i.e., a precision constant current reference driving an electrical load.

Abstract: A fluid pressure regulating valve having a two-stage high and low flow rate control capability combined with a natural-LP gas control pressure changeover uses a spring biased pressure regulating diaphragm controlling a fluid through an orifice defined by a valve seat. A solenoid valve armature is attached to a spring providing the spring bias for the diaphragm and is arranged to be actuated by a selectively energizable solenoid coil. An extension of the armature is captured by a step regulator assembly which is threaded into a valve body containing the regulating diaphragm. The high fire and low fire adjustments in the step regulator assembly are on non-moving threaded members attached to the regulator assembly and bearing on the extension of the armature to vary the energized and deenergized position of the solenoid armature.

Abstract: A control system having combined closed loop and duty cycle functions uses a differential amplifier for amplifying the difference between a setpoint or reference temperature for a system to be controlled and a detected system temperature, a thermostat having a differential circuit for providing a predetermined hysteresis lag for an output of the amplifier and a duty cycle generating circuit for changing the operating potential of the differential circuit in accordance with a predetermined duty cycle to shift the operating point of the differential circuit.

Abstract: Impurity compensation for compensating the analysis of the calorific content for fuel having an unknown amount of a known additional constituent of interest (impurity) is disclosed. In the illustrative embodiment oxygen is the impurity. In that embodiment, the fuel containing the impurity is combusted to achieve substantially stoichiometric combustion by varying the air/fuel ratio supplied to a combustion means by a rotary speed controlled in response to the sensing of oxygen in the combustion products. A first measurement of the calorific content is made using a normal operation of the analyzer and a second measurement is made using a known amount of air added to the combustible gas stream. The true air/fuel ratio and the calorific content is then computed using a predetermined relationship among the system variables.

Abstract: A D.C. power control for a D.C. solenoid actuator which may be used for a D.C. solenoid operated valve uses a timer circuit for switching from an initial high pull-in power after a predetermined delay to a low hold power for the valve solenoid utilizing a pulse control where the valve "on" time is held constant and the "off" time is varied. The pulses are high frequency to prevent the valve from switching with each of the pulses while enabling the average current in the valve solenoid coil to be controlled independently between the pull-in and hold current values.

Abstract: An A.C. power control circuit for a D.C. solenoid actuator which may be used for a solenoid operated valve uses a triac circuit to initially apply A.C. line voltage to energize the solenoid coil of the valve to be actuated to provide valve pull-in power. A capacitor in an RC network is concurrently charged to a D.C. level, and the D.C. voltage on the capacitor is used to control the gate of the triac. After a predetermined delay as determined by the RC network charging time of the capacitor, the triac is phase controlled to produce a change in the current applied to the solenoid coil. In one embodiment, the voltage applied to the solenoid coil changes at this time from the full sine wave voltage of the A.C. source to a voltage pulse which is only a portion of the positive half of the input sine wave. This voltage produces a change in the power applied to the solenoid coil to a hold-in power level. This circuit produces a current pulse phase control of up to 90.degree..

Abstract: A two-stage solenoid valve uses a pair of stacked coaxial armatures in a cylindrical sleeve housing. A first armature is provided with a fluid sealing ring and is urged by a first spring to peripherally seal an adjacent internal fluid port in a valve base supporting a first end of the sleeve housing. The first armature is provided with a coaxial bore extending through the armature and coaxial with the fluid sealing ring to form a fluid channel. The second armature also has a coaxial bore extending therethrough with a resilient sealing member slideably retained within the bore. A second spring is arranged to urge the resilient sealing member against a first end of the bore in the second armature and to extend therefrom to a fixed plug in a second end of the cylindrical housing. The resilient sealing member cooperates with a fluid port defining an end of the coaxial bore in the first armature opposite the end of the first armature having the fluid sealing surface.

Abstract: An adaptive control system uses a controller for controlling an air temperature treatment apparatus at a reduced energy consuming level during periods of non-occupancy of a building and for energizing the air treatment apparatus before occupancy so that a desired internal building temperature is reached by a time of occupancy.

Abstract: A switching valve has at least one plate-shaped piezo-electric element having a free end which is supported in a sealed chamber, at least two fluid directing nozzles arranged to be opened or closed due to the position of the free end of the piezo-electric element and a fluid output passage communicating outwardly from said sealed chamber. An electric-pressure converter uses the switching valve, a pilot relay for converting a fluid pressure signal delivered from the output passage into a standard air pressure signal, a pressure sensor for converting the pressure signal from said pilot relay into an electrical signal, pulse-width modulating means for providing a pulse-width modulated signal, which corresponds to the deviation between the electrical signal from the pressure sensor and an external reference electric signal, for energizing the plate-shaped piezo-electric element in the switching valve.

Abstract: A pressure sensor header uses a layered assembly of a first and a second metal layer with an intermediate ceramic layer having a radial surface groove providing a fluid passage between a peripheral fluid port and a hole extending through the first layer between the groove and an outer surface of the first layer. A plurality of electrically conductive pins are arranged to extend through the layered assembly and are sealed to the upper and lower metal headers with glass seals to provide a fluid-tight seal. The seals on the metal pins provide a means for retaining the layered assembly in a predetermined configuration while the radial groove and the hole through the first layer provide a fluid path to a pressure transducer element supported on the first layer of the header and having an internal fluid path aligned with the hole through the first layer. Electrical connections to the metal pins provide electrical signal paths between the transducer element and associated electrical circuits.

Abstract: An electromagnetic flowmeter uses a cylindrical inner tube including an electrode, an excitation coil and an inner portion of an electrical connector with the inner portion being located on an outer circumferential surface of the tube and electrically connected to the electrode and the coil, an outer tube housing the inner tube along its axis and having an access opening extending transversely through the outer tube housing and an electrical connector support externally inserted through the access opening for supporting an outer portion of the electrical connector to selectively mate with the first portion of the connector to provide separate electrically conductive paths through the connector for connections to the electrode and the excitation coil.

Abstract: A thin bed sorption/desorption apparatus includes a heater element laminated within a high temperature chemically inert polymer with an adhesive on the outside of the laminate being used to attach a thin film of small particle size sorptive material. Various embodiments of the apparatus are each arranged to provide a flow of a sample to be analyzed across the surface of the sorptive material. The method for making the thin bed sorption/desorption apparatus includes the steps of encapsulating a thin-film heater element in a laminated structure of a polyimide which is a high temperature, chemically inert polymer. The outside surface of the laminate is coated with a polyimide adhesive which is diluted with dimethyl formamide. The sorptive material in the form of a powder having a maximum particle size of 100 mesh is applied to the wet adhesive. Subsequently, the coated structure is heat cured at approximately 220.degree. C.

Abstract: A quasi-continuous sorption/desorption analysis method includes the steps of admitting a sample to be analyzed to a stationary sorption/desorption bed for adsorption therein. The flow rate of the sample across the bed is maintained at a high rate for an extended period of time to produce a long sorption time cycle by the sorption bed. Conversely, the subsequent desorption of the sample from the sorption bed is achieved by selectively activating a rapid bed heating element and providing a concurrent low flow rate across the bed to desorb the sample from the sorption bed during a very short desorption time cycle to make the ratio of the sorption/desorption periods as large as possible. The desorbed sample is ultimately conducted to a sample constituent detector for analysis.