Abstract: A control arrangement for a fuel ignition system including redundant pilot and main valves, includes a thermal heat sensor mounted on a heat exchanger or in an exhaust stack of main burner apparatus and having a heating element which is energized in response to operation of thermostatically controlled contacts to close associated contacts to effect energization of the pilot valve permitting fuel to be supplied to a pilot outlet and the main valve which is operated when a pilot flame is established, the heating element being deenergized when the main valve is operated and the heat sensor being responsive to heat from the main burner to maintain the contacts closed maintaining the pilot valve energized. The heat sensor responds to a flame out condition to deenergize the pilot valve, thereby interrupting fuel flow to main valve.

Abstract: A control arrangement for a heating system including a furnace having a fuel-fired burner apparatus and a vent stack with a motor driven damper plate pivotally mounted within the stack, includes a stack damper control circuit including first and second limit switches which permit energization of a drive motor in response to a request for heat, premitting the damper plate to be driven to an open position, and for energizing an interlock switch which prepares an energizing path for fuel supply valves of the system, the first limit switch being operated when the damper plate approaches the open position to complete the energizing path for the fuel supply valves prepared by the interlock switch, and the second limit switch deenergizing the motor when the damper plate is driven to the fully open position. The motor is reenergized at the end of the heating cycle to drive the damper plate to the closed position, and the second limit switch deenergizes the motor when the damper plate reaches the closed position.

Abstract: A flat solar collector apparatus includes an inner energy absorber plate having a absorber surface and energy transfer passageway connected to a storage unit. A transparent cover is secured in outwardly spaced and sealed relation to the absorber plate to define a sealed air space therebetween. The cover includes a pair of stacked, transparent sheets having light transmitting conductive coatings on the opposed sides or faces. Each conductive coating is provided with an electrical connector means for connection to a suitable power supply with an insulating spacer located between the outer peripheries defining a chamber filled with nematic liquid crystals. A D. C. or A. C. voltage source connected to the coatings controls the light scattering characteristic of the crystals and thereby changes the cover from a normally highly transparent to an increasingly translucent state, and thereby the energy transmittance of the cover.

Abstract: A differential pressure cutout switch including a low pressure operating point assembly and a high pressure operating point assembly which are mechanically linked and are operable to respond to first and second pressures supplied over respective first and second pressure inlets of the switch to control a contactor switch assembly which is movable to a first position to provide an open circuit between outputs of the switch and movable to a second position to connect a resistance of a finite value between the outputs as a function of the difference between the two pressures. The differential pressure cutout switch is described with reference to an application in a protection control system for monitoring lubrication oil pressure for a compressor of a refrigeration system.

Abstract: A control arrangement for a fuel ignition system to provide an interlock on start-up to prevent energization of fuel valves under certain failure conditions includes a pulse generating circuit operable when enabled to provide pulses for enabling a first switching device which energizes a pilot valve to supply fuel to a fuel outlet and prepares an energizing path for a main valve, and a second switching device enabled by a flame sensing circuit when a flame is established at the outlet to close associated contacts to complete the energizing path for the main valve and to cause the pulse generating circuit to continue to generate pulses for maintaining the first switching device enabled, the pulse generating circuit being inhibited whenever the contacts are closed at start-up, or close after the system is in a lock out state, preventing the enabling of the first switching device to maintain the pilot valve and the main valve deenergized.

Abstract: A control arrangement for a fuel ignition system for providing an interlock on start-up to prevent the energization of fuel valves of the system under certain failure conditions includes a switching device which is energized over normally closed contacts of a flame relay to close associated contacts to prepare an energizing path for a pilot valve and to energize an interlock relay which completes the energizing path for the pilot valve, a main valve being energized and the switching device being deenergized to interrupt the energizing path when the flame relay is operated in response to the establishing of a pilot flame, and the pilot valve and the main valve being maintained energized over a holding path provided by the interlock relay, the energization of the pilot valve and the interlock relay being prevented whenever the normally closed contacts of the flame relay are open on start-up.

Abstract: A proportional motor control circuit for supplying bidirectional drive to a motor as a function of variations of a sensed parameter includes a temperature sensing amplifier which is responsive to an error signal indicative of deviations of the parameter from a set point to provide an output signal representing the direction and amount of the deviation, and a pair of operational amplifiers, each of which serves as a load for the other amplifier, which are responsive to the signal output of the temperature sensing amplifier to determine the polarity of the energizing potential applied to a D.C. motor over motor drive circuits. The motor control circuit is described with reference to an application in an environmental control system to effect positioning of dampers located in air ducts for supplying heated or cooled air to an area in response to changes in the air temperature in the area.

Abstract: A fuel ignition system including a control arrangement which provides an interlock on start-up to prevent the energization of fuel valves of the system under certain failure conditions, and an igniter which is enabled when the system is activated to provide ignition sparks for igniting fuel supplied to a fuel outlet, the igniter being disabled when a flame sensing relay operates and a timing circuit of the igniter permitting the igniter to provide ignition sparks for a predetermined time duration following the operation of the flame sensing relay.

Abstract: An environmental air distribution control system regulates the flow of air under pressure by using the system pressure itself to effect the desired control. This is accomplished by using one or more pressure regulating valves, each pressure regulating valve being adapted to selectively vary the pressure drop across its output impedance to thereby control the rate of flow of air.

Abstract: A control system including a programmable multiple channel digital controller which is operable to generate control signals which are transmitted over electrical power lines of a building complex for enabling receivers associated with functional devices for controlling the operation of functional devices, the transmitter being operable to transmit control signals during selected ones of a plurality of data channels which define a data frame, and in one embodiment, different ones of the receivers are programmed to respond to control signals transmitted in different data channels for controlling the associated functional device. In another embodiment, the transmitted control signals are coded to represent an address of one or more of the receivers and a control command, each receiver comparing its address with the transmitted address, and the addressed receiver effecting the control function represented by the control command.

Abstract: A pneumatic actuator includes a cup-shape cylinder body housing a piston and having a generally flat base with a mounting hub projecting outwardly. A piston rod is slidably mounted in the hub and connects to a load such as a damper in an air mixing box. The base is formed with a bearing recess or depression means encircling the hub. The recess defines a spherical sector offset from the center of a complete sphere of the same radius. An annular swivel ring includes an inner diameter adapted to loosely fit over the hub and includes an outer periphery which is generally spherically shaped and defines a central spherical sector having a maximum planar diameter slightly larger than that of the sector defined by recess. The swivel ring is a two-part member having interconnecting slot and projection elements providing a snap joint connection, with the mounting plate firmly clamped therebetween. The swivel ring with the attachment plate fits over the mounting hub.

Abstract: A control arrangement for use in an automatic fuel ignition system for providing electronic detection of a leak condition for a pilot valve operable to supply fuel to a pilot outlet for ignition to establish pilot flame includes a flame sensing circuit which effects operation of a main valve when a pilot flame is established, the flame sensing circuit maintaining the main valve deenergized when a pilot flame is established during an ignition interval and permitting a delay device to deenergize the pilot valve for a time to interrupt the supply of fuel to the pilot outlet to attempt to extinguish the pilot flame, and a time out device operable to deactivate the system when the delay device fails to cause the pilot flame to be extinguished, the flame sensing means overriding the delay device and the timeout device when the pilot flame is established at the end of the ignition interval.

Abstract: A gas valve having first and second redundant valve members, disposed in a passageway between an inlet and an outlet of the valve which are individually operable to open and close respective inlet and outlet valve ports, and a pressure regulating apparatus interposed between the inlet and outlet valve ports operable to supply gas to the outlet valve port initially at a pressure lower than the inlet pressure when the first and second valve members are operated to open respective valve ports, and to gradually increase the pressure of the gas supplied to the outlet valve port until the outlet pressure equals a value intermediate the inlet pressure and the initial outlet pressure, as established by a pressure regulator spring of the pressure regulating apparatus. The gas valve is disclosed with reference to an application in a fuel ignition system to regulate gas flow to a combustion box to minimize ignition noise and rollout of gas flame from the combustion box.

Abstract: A serial data communication loop system includes single input-output controllers and/or dual message transmission with a novel adaptor unit for converting from a single to dual message frame and/or from a dual to single message frame. The message frames are multiple bit binary coded signals. The adaptor unit includes first and second converting sections, the first converting from a single input to dual output message frames and the second from a pair of identical messages to a single message output. The first section includes an amplifier connected to a polarity and level sensor and to a time delay which activates a disable timer to the amplifier and a strobe timer to operate a pair of transmitters to transmit the dual message frames. The second section includes a pair of receivers connected to a logic selector in combination with individual monitors which encode the status at the receivers to normally transmit from one receiver and automatically change to the second if the first fails.

Abstract: A fail-safe energizing circuit for effecting the operation of a functional device, such as a relay, includes a resistor and a capacitor connected between outputs of an AC signal source which supplies an AC signal for charging the capacitor, a normally disabled silicon controlled rectifier connected in shunt with the capacitor and an operate coil of the relay and operable when enabled to provide a discharge path for the capacitor permitting the capacitor to discharge over the relay coil to operate the relay, and a control circuit operable to provide an enabling signal derived from the AC signal for enabling the silicon controlled rectifier. The energizing circuit is described with reference to an application in an automatic fuel ignition system for controlling the operation of a relay which energizes a fuel valve of the system.

Abstract: A method and control arrangement for a heating system including solar heating apparatus and a conventional fuel-fired heating apparatus wherein heat load of the heating system and solar heating source capability are compared, and the heating system is switched to solar heating whenever the heating capability of the solar heating apparatus exceeds the heat load of the system, the heating system being switched to the conventional heating apparatus only when the heat load exceeds the heating capability of the solar heating apparatus.

Abstract: An automatic fuel ignition system which provides automatic detection of a leak condition for a pilot valve which is operable to supply fuel to a pilot burner for ignition to establish pilot flame and a main valve which is operable to supply fuel to a main burner for ignition by the pilot flame of the system including a control circuit operable in response to a request signal to activate the system tentatively, a delay circuit which delays the operation of the pilot valve for a first delay period after the occurrence of the request signal, a flame sensing circuit which senses the presence of the pilot flame and effects operation of the main valve after a second delay period established by the control circuit, the flame sensing circuit being responsive to the presence of a flame at the pilot burner during the first delay period or at the main burner during the second delay period to cause the system to be deactivated.

Abstract: A fuel ignition control arrangement for use in a fuel ignition system includes a control circuit responsive to a thermostatically-controlled circuit element for the fuel ignition system for causing a gaseous fuel to be supplied to burner apparatus of the system, a spark-producing circuit responsive to the thermostatically-controlled element for igniting the fuel supplied to the burner apparatus, a timing circuit responsive to the thermostatically-controlled element for de-energizing the control circuit after a predetermined timing interval, and a flame sensing circuit responsive to the ignition of the fuel supplied to the burner apparatus for maintaining the control circuit in fuel supplying condition.

Abstract: An alarm transmission system for transmitting alarm and status information from a secured area to a monitoring area over a transmission line includes a code source in the secured area which provides a line security code for securing the transmission line, an alarm source which modifies the line security code in the event of an alarm condition, and a data selection network which enables preselected bits of the line security code and a further bit representing the access/secure status of the secured area to be transmitted to the monitoring area during preassigned time slots for comparison at the monitoring area with corresponding bits of a reference code provided by a reference code source, and an access/source status bit to permit an alarm to be indicted when one or more of the compared bits differ.

Abstract: A stack damper control arrangement for use in a heating system including a furnace having a fuel-fired burner apparatus and a vent stack for conducting combustion products away from the burner apparatus and a damper plate pivotally mounted within the stack and movable between a fully open and a fully closed position, includes a reversible drive motor which is energizable in response to a request for heat to drive the damper plate to the open position, a first limit switch operated when the damper plate reaches the open position to effect the deenergization of the motor, the motor being reenergized at the end of the heating cycle to drive the damper plate to the closed position, and a second limit switch operated when the damper plate reaches the closed position to effect the deenergization of the motor.