Abstract: An apparatus for controlling an electrical appliance coupled with an output terminus and configured to operate in response to an alternating input signal, such as input AC power. The apparatus comprises a reference signal generator for receiving the input signal and generating a reference signal (either V.sub.RAMP or V.sub.CONTROL) in response to the input signal, and a control circuit for controlling connection of the input signal to the output terminus in response to the reference signal and to a user-defined set-point signal. The control circuit is coupled with the reference signal generator and with a set-point terminal. The set-point terminal receives the set-point signal and the control circuit controls connection of the input signal with the output terminus in response to a predetermined relationship between the reference signal and the set-point signal; the apparatus is capable of generating a modified periodically interrupted AC power output based on an AC power input.

Abstract: A fail-safe closed damper for installation in a system of ducts. The damper includes at least one damper blade connected to a spring-loaded shaft. A power-actuated unit is employed to disengage a coupling which interconnects the spring-loaded shaft to an operating linkage. The use of the power-actuated unit ensures that the damper will be tripped at the appropriate predetermined temperature and will not be affected by the large frictional forces imparted on the components of the damper by the biasing spring or by such external factors as dust, humidity and dirt. The damper employs a sensor having dual sensing devices and which is centrally disposed in the duct to ensure receipt of a representative sample of airflow. The damper further includes a damper blade position indicator for sensing whether the damper blade is open or closed.

Abstract: A valve actuator mechanism for supplying a selectively adjustable close-off force to an associated valve. The mechanism comprises a means for urging the valve plunger into engagement with the valve seat with a predetermined initial force and resistive means for generating a resistive force such that the close-off force is less than the initial by a predetermined amount. The resistive force can be selectively adjusted also.

Abstract: A modular fluid control module having a plug-in connector is provided for control of one or more functional load devices in response to fluid condition and demand input signals. The module includes a fluid circuit board having top and bottom plate members bonded to a common center plate. The top and bottom plates each have a plurality of parallel flow lines. The first and second parallel lines are substantially perpendicularly related to define an X-Y coordinate grid. The center plate has openings establishing preselected connection of the parallel flow lines in the top and bottom plates. The top plate includes a multiple input/output port connector which includes a plurality of ports connected to the parallel flow lines of the top plate. Each of the top and bottom plates includes a plurality of plug-in logic and control ports connected to select internal flow lines of the corresponding plate.

Abstract: A modular pneumatic control apparatus controls a mixed air handling units in an air conditioning system. The apparatus includes a single configured manifold module plate having a plurality of function module plug-in connectors and a plurality of input/output plug-in connectors. Function modules have complementary plug-in connectors for connection to the manifold module are designed with common opposite outer plates having surface passageways abutting a center plate with openings to define a particular circuit. The outer plates have all external ports for defining any function module used in any system. The manifold module is a constant architecture and acts as an interface between the system sensors and load devices and the function modules which create the desired complex control systems. Only a relatively small number of function modules are required.

Abstract: A sensing probe unit includes an electrically nonconductive polymeric layer charged with a permanent electric charge to form an electret and intimately bonded to a compensating metal electrode. In the fabrication, the polymeric layer is cleaned and the metal electrode affixed to one surface by vapor deposition, lamination or baking. The polymeric layer may also be applied by coating the electrode with dielectric particles and then heating the subassembly to fuse the particles into an integral layer and to bond the fused layer to the electrode. The subassembly is thermally destressed and the polymeric layer is thereafter charged by triboelectric charging, corona discharge or electron beam charging, or by liquid contact charging processes. In the latter, a Freon-type or other similar liquid having good wetting properties and high evaporation rate is used as a contact charging liquid which creates a particularly stable electret. The sensing probe is stored to prevent loss of charge and sensitivity.

Abstract: A square root signal extractor generates an output signal which is a square root function of an input signal. First and second diaphragm amplifiers have cascaded output chambers connected to a high gain output amplifier. The first and second amplifiers are connected as the non-inverting input and the inverting input respectively of the operational amplifier. A high gain output diaphragm amplifier is connected to the inverting amplifier output. The output diaphragm amplifier is constructed such that only a low level input pressure change is required to create a full swing of the output pressure. A non-linear input restrictor and a linear feedback resistor are connected to the input chamber of the inverting amplifiers. The feedback resistor has a significantly greater resistance than the input resistor. The non-inverting diaphragm amplifier is connected to the transmitter by a fluid repeater. A reference signal source is connected to the input restrictor and thus to the inverting input.

Abstract: An optimal start programmer for starting a heating or cooling cycle for an intermittently occupied building includes a digital counter which is enabled at the start of a pre-occupancy "search" period and accumulates counts from a timing source. A digital to analog converter is responsive to the cumulative output count of the counter circuit for generating a staircase or ramp signal which provides a time-variable set point signal during the search period. In the heating mode, the reference signal to the digital to analog converter is a signal representative of the outdoor ambient temperature; and in the cooling mode the reference is a constant signal. The operating mode of the system during the search period is determined by a mode selection circuit which is responsive to a heating mass signal and a cooling mass signal to automatically determine whether the system is to operate in a heating mode, a cooling mode or an inhibit mode in which neither the boilers nor the chillers are actuated.

Abstract: An air pollutant and/or fire combustion sensing apparatus includes a capacitive sensor having spaced sensing electrodes producing a free space mounted within an environment subject to possible fire or the like. One of the sensing electrodes has an outer dielectric layer for absorbing contaminating gaseous products. The electrodes are connected to a high voltage power source for producing a charged capacitor with a high intensity static electric field of substantially 5.times.10.sup.5 V/M up to the dielectric breakdown of air in the free space or gap. The electric field reacts upon the contaminating gaseous products of combustion and environmental pollution and produces an opposing electric field with a net change in the electric field and the summated voltage appearing across the electrodes. A high input impedance detecting circuit with good electrometer characteristics responds to the change in the field.

Abstract: A heater vent having a temperature responsive damper such as a bimetallic element is disclosed. A shroud-like structure is positioned to cooperate with the temperature responsive element to close the vent at an elevated temperature and thereby reduce loss of residual heat while permitting the combustion gases to be completely purged from the firebox. For safety, movement of the temperature responsive element is uninhibited in all positions with complete vent closure occurring at ambient temperature and with the damper open during heater burner operation.

Abstract: The system includes a damper plate equipped with a draft controller or sensing switch and a motor for positioning the damper plate to control the furnace draft. Upon generation of a call-for-heat signal, an initialization signal drives the damper off its closed position. From then on, draft must be sensed by the draft controller switch to complete the cycle to open the damper plate. When the damper plate is fully opened, a fuel and ignition control circuit is energized to supply fuel to the furnace, and an electronic timer is energized to generate a signal which establishes a trial-for-draft period. When the fuel is ignited, the draft will increase and energize the motor to move the damper plate off the fully open position during the trial-for-draft period, and thereafter, the position of the damper plate is controlled by the draft controller switch to achieve a proper draft within design range.

Abstract: When a call for heat is established, a flame relay is actuated for a predetermined time by means of a cycling timer. Upon this initial actuation, the flame relay inhibits a checking relay and initializes a trial-for-ignition (or simply "ignition") timer. After the cycling timer times out and the flame relay has been completely cycled, which establishes operativeness of the flame relay and flame sensing circuitry, the checking relay is enabled and actuated for the ignition period. The checking relay then actuates the pilot valve and a spark generator to start a pilot flame. If a flame is sensed, before the ignition timer times out, the flame relay actuates the main valve and establishes a holding current for the ignition timer so that the checking relay continues to be energized. If a flame is not sensed during the trial period, the ignition timer disables the checking relay, thereby de-energizing the pilot valve before the main valve is opened.

Abstract: A dual thermostat apparatus includes two thermostats which generate fluid control signals proportional to room air temperature. The thermostats are matched leakport pressure sensors having a signal orifice and a bimetal lid element to generate back pressure signals linearly related to temperature. The bimetal elements have adjustment cams to set the reference position with respect to the orifice. The cams are connected to a common shaft and dial to provide simultaneous and opposite readjustment with respect to the reference pressures. The signals are applied to separate signal chambers of the duplex relay, with a pressure regulator connected to the heat signal chamber to limit the operative pressure level of the heating signal to a selected maximum switchover pressure. The duplex relay controls a pressure supply valve for supplying a proportional pressure signal to a common output line to pneumatic operators of a heating valve and a cooling valve.

Abstract: A pilot assembly includes a base having a cylindrical side wall which holds an electrode subassembly and glass preforms in place for fusing the glass to secure the electrode subassembly to the base. Prior to fusing, a spark electrode is assembled by inserting it into a metal clip receptacle held in a ceramic insulator body forming a part of the electrode subassembly. A pilot tip and orifice subassembly are secured to the base. Fusion of the glass and brazing of the metal including the high tension clip to bring it to spring temper for connection to a plugged wire are accomplished in a single step of heating. The pilot tip includes a locator member which holds the spark electrode in place during fusing and establishes the spark gap. It is removed after fusing.

Abstract: A control circuit for a fuel supply and ignition control system controls the operation of pilot and main valves of the system and of a motor which controls the positioning of a vent stack damper plate to normally close the vent stack and to open the vent stack at the start of each ignition cycle. At the start of each ignition cycle, a start relay is operated to energize the pilot valve and a spark generator for a trial for ignition interval defined by the excursion time of the damper plate as it is driven to the open position. When the pilot fuel is ignited, a flame sensing circuit operates a flame relay which completes a holding path for the pilot valve and when the damper plate reaches the fully open position, limit switches connect the main valve to the holding path and deenergize the drive motor and the start relay.

Abstract: A fluid signal inverting unit includes a motion balance unit having a lever which operates a valve. The balance lever is supported at the opposite ends by a pilot signal chamber and a feedback signal chamber and an intermediate pivot support is coupled to position a back pressure leakport valve. Each chamber includes an outer matched linear metal diaphragm fixedly connected to the aligned end of the lever. Increases in pilot pressure result in the outward movement of the linear diaphragm and corresponding outward and pivotal movement of the lever. The lever tends to move away from and open the valve resulting in a decrease in the output pressure and an inverted output pressure signal which may be further amplified and transmitted to a flow booster relay, and as negative feedback signal to the feedback chamber. Decrease in pilot pressure results in an opposite action and an increase output pressure.

Abstract: A fuel supply and ignition control system for controlling the operation of pilot and main valves in an intermittent pilot type system. At the start of an ignition cycle, the pilot valve is operated to supply fuel to a pilot outlet for ignition by sparks generated by a spark generating circuit. When the pilot fuel is ignited, the pilot flame bridges the spark gap, and a flame sensing network, which is connected in circuit with the spark electrodes, generates a flame signal which is applied to an enabling circuit which responsively effects operation of the main valve. The enabling circuit includes a controllable switching device which in one embodiment, is maintained disabled in the absence of a flame signal and is enabled to cause a flame relay to operate and energize the main valve when a flame signal is provided.

Abstract: An ignition system for use with a source of dc (or full-wave-rectified) power without the need for an inverter includes a flame sensing relay and a checking relay interlocked to achieve lockout if the proper starting sequence or timing are not met or if a flame-out occurs during operation. The checking relay is energized in response to a call-for-heat signal to isolate the flame detection circuitry from its source and commence a trial-for-ignition period in the flame detection circuitry which includes a timing circuit. The timing circuit actuates the flame-sensing relay during the trial-for-ignition period. The flame sensing relay energizes the fuel valve and a spark generator to ignite the fuel. If a flame is detected during the trial-for-ignition period by a flame probe, the timing circuit is disabled and operation continues until the call for heat is terminated as long as the flame is sensed. Another circuit senses flame at the spark gap and disables the spark gap generator after a flame is established.

Abstract: A printed circuit board with electronic components wired thereto has a conformal insulating coating consisting of a single component of essentially pure urethane formulation and a minor amount of fumed colloidal silica powder. The insulating coating covers asperities and protrusions as well as the conductors and circuit components while maintaining a transparent characteristic. The coating material is made by mixing of the small proportion of silica with essentially pure urethane formulation under controlled conditions to prevent moisture contamination of the materials. The mixture is thoroughly mixed, deaerated under reduced pressure with a pulsating pressure to break any air bubbles and remove essentially all air. The coating is applied in an environment having at least 30 percent relative humidity and within a confined area defined by an encircling dam masking compound. The coating is allowed to partially cure at room temperature and the confining dam compound removed.

Abstract: A mixed air conditioning controller is formed as a factory assembled and adjusted unit in a compact housing, with simple and direct input/output field connectors. Various temperature and humidity input devices are field connected to produce a sequenced control of the air dampers and mechanical cooling and heating devices, as well as auxiliary devices. The controller includes a primary input related to room demand, an outside air temperature input, with an interlocked control to the damper, a fan status input, a minimum air supply control and a by-pass switch having a low limit input. The logic network connecting the input/output includes pneumatic switching, pressure selecting and comparing devices of a diaphragm-controlled-orifice construction connected to function as fluidic repeaters, pressure regulating valves and pressure isolating and switching devices. The controller includes a conditioning channel and a damper channel.