Abstract: A method of controlling a space heating system having a plurality of electrical resistance heaters includes the steps of computing the aggregate number of resistance heaters required to be energized to raise the actual temperature within a space to a set point temperature. This aggregate number may have integer and fractional components. One of the resistance heaters, denominated a controlled heater, is adapted both for continuous energization or for modulated control by intermittent energization. A group of second resistance heaters is adapted for continuous, staged energization, this group including a number of heaters equal to the integer component. Energization of the heaters comprising this group is preferably sequential after the lapse of a preselected interstage time delay between energization of the controlled heater and the first heater of the group.

Abstract: An apparatus useful in determining the value of a capacitor includes a first bilateral switch for flowing a charging current through a resistive element to an initially-depleted first capacitor of known value. The first capacitor is thereby charged to the potential of a trigger reference over a resulting first time period. A second bilateral switch is provided for flowing a charging current through the same resistive element to an initially-depleted second capacitor, thereby charging it to the potential of the same trigger reference over a resulting second time period. A device such as an oscilloscope or frequency counter is used for determining these time periods and the value of the unknown second capacitor may thereupon be computed using disclosed formulas.

Abstract: A motor-driven rotary actuator includes an electric drive motor adapted to be configured for providing one of a plurality of output torques. A power transmission is coupled to the drive motor and includes a rotatable output shaft and drive elements adapted to be formed of disparate materials selected for transmitting one of the output torques. An electric controller is coupled to the motor for providing rotation positioning control of the output shaft in response to digital command signals.

Abstract: In general, a motorized valve actuator includes an electric drive motor having a rotatable shaft for providing an actuating torque. An output member is provided for operating a valve to be coupled thereto and a gear member is adapted to be mounted intermediate the shaft and the output member and in a first position or in a second position. The gear member includes first means for driving coupling of the motor shaft and the output member when the gear member is mounted in the first position and second means for decoupling the output member from the shaft when the gear member is mounted in the second position. In the latter position, the gear member permits the output member to be driven by a source of power external to the actuator.

Abstract: A light fixture for underwater use in swimming pools has a waterproof gasket between the lens and the housing enclosing the electrical components. The gasket is fabricated of an off-white, neoprene material and is devoid of any coloring agents, such as carbon black, which are subject to leaching by chlorine-containing water in the pool. As a result, discoloration of the wall of the pool and also of the lens will not occur, even where chlorine concentrations are relatively high.

Abstract: In general, a sealing apparatus for substantially preventing the flow of air through a damper assembly having a plurality of movable vanes includes a first, rigid sealing member having a generally circular cross-section and adapted to be attached to a first edge of a first movable vane. The first edge is movable through a first arc between a damper-open position and a damper-closed position. A second resilient sealing member has a generally rectangular cross-section and is adapted to be attached to a second edge of a second movable vane. The second edge is movable through a second arc between the damper-open and damper-closed positions. The sealing members make substantially line contact one with the other as the edges are moved toward the damper-closed position and are in substantially gas flow-preventing area contact one with the other when the vanes are in the damper-closed position.

Abstract: A capacitive pressure transducer of the deflecting diaphragm type is adapted to be coupled to a capacitance transducing circuit and includes a generally planar, electrically conductive base member support upon a first insulative substrate. A sensor member is supported upon a second insulative substrate in a generally parallel, spaced relationship from the base member and coacts with the base member to form a sensor capacitor. A reference member is generally coplanar with and in electrical isolation from the sensor member and coacts with the base member to form a reference capacitor. The sensor and reference members each have a plurality of segments interposed one with another. The sensor and reference capacitors have pressure-dependent capacitance values Cs and Cr respectively such that, for discrete pressures selected within an operative range of pressures, the output signals from the transducing circuit will be substantially linear.

Abstract: A stationary horizontal cylindrical reactor for the production of lead oxide utilizes a series of horizontal rotating blades to promote and maintain the oxidation reaction, to provide a particle size reduction and to effect centrifugal classification of the lead oxide produced in the reaction. The preheated reactor chamber is supplied with raw lead, air and water, and the use of the entire reactor chamber-blade interface as a reaction zone results in a highly energy efficient and high rate production process. The process is extremely versatile and can be used to produce low free lead (less than 1%) litharge (PbO) and high free lead or leady litharge on a consistent high volume basis.

Abstract: A control apparatus for repetitively verifying the integrity of a main fuel valve control circuit in a standing pilot burner system includes a probe circuit adapted to receive an electrical signal representative of the presence of a standing pilot flame and a first circuit which coacts with the probe circuit for energizing a first relay in response to the electrical signal. A second circuit is adapted to receive a heat demand signal and coacts with the first circuit for sequentially disabling the probe circuit, de-energizing the first relay, energizing a second relay, re-enabling the probe circuit and re-energizing the first relay to actuate a main fuel valve.

Abstract: In general, an electronic control module includes a module frame adapted for swingable mounting to a rail member. The module includes a plurality of bus conductors constructed and arranged to engage the bus conductors of adjacent modules when mounted. The module also includes a plurality of electrically-conductive pads for engaging a circuit board which is attachable to the module frame. Terminals are included for the connective termination of external wiring. The module is swingably removable from a rail member while yet avoiding movement of a module which may be mounted adjacent thereto. The invention is particularly useful for the construction of electronic digital communication systems used with heating, ventilating and air conditioning equipment.

Abstract: The compressor motor controller of the present invention includes a hot motor detector adapted to be coupled to a plurality of temperature sensors for detecting an overtemperature condition of the compressor motor. The hot motor detector incorporates logic switching means for generating a motor control signal. A self diagnostic sensor is coupled to the hot motor detector for detecting an electrically shorted condition of the temperature sensors while a low voltage detector is coupled to the hot motor detector for sensing a low line voltage condition. Means are provided for protecting the compressor motor against the undesirable effects of short cycle operation while a lubricating oil pressure detector receives signals from a pressure transducer which are representative of oil pressure.

Abstract: The thermostat of the present invention includes a sensor for providing a signal representative of the actual temperature within a space. A microcomputer is coupled to the sensor and intermittently utilizes power at a first level when in an operating state for controllably generating output signals in response to the temperature signal. The microcomputer is adapted to be connected to a battery as a sole power source therefor. An isolating interface device such as an electromagnetic relay is coupled to the microcomputer and is adapted for connection to temperature-affecting equipment such as a heating or cooling system controller. The relay actuates the equipment in response to output signals from the microcomputer. A voltage detection circuit may optionally be provided for signalling a low battery voltage condition.

Abstract: The invention facilitates the reception of bus-transmitted digital signals in the presence of electrical noise and includes a transmitter adapted to be coupled to a two wire communication bus. The transmitter has a controllable transistor for switching one wire of the bus between zero and reference voltages, thereby generating digital output signals. A receiver is coupled to the bus for receiving digital input signals which define a first wave form and are transitory between a first voltage and a second voltage. The receiver includes an R-C circuit for shaping the first wave form to a second wave form and a hysteresis switch for providing a first output condition when the second wave form transcends through a first intermediate voltage in a first transition direction. A second output condition is provided when the second wave form transcends through a second intermediate voltage in a second transition direction.

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: A low level, microprocessor based direct digital system controller includes power supply means for providing a source of regulated electrical power to the controller. A field programmable processor means transfers selected data base information to and receives status signals from a field interface means, digitally executes control and energy management algorithms respecting those signals in accordance with computer program routines selected from a library of mnemonically identified routines residing in the read only memory (ROM) portion of the processor means. The processor means responsively directs programmed data and digital command signals to the field interface means which periodically updates the data base of the processor means, analyzes and conditions signals received therein from the processor means and from remote data points and selectively controls the data points.

Abstract: The hinge of the present invention comprises an I-shaped support bracket including an elongage body member and a plurality of laterally extending flanges. A panel bracket is adapted for attachment to a generally planar panel member and includes means for pivotably coupling the panel bracket to the flanges along a first pivot axis. A door bracket is provided for attachment to a generally planar door member and includes means for pivotably coupling the door member to the flanges along a second pivot axis. When closed, the supported door member is disposed in a reference plane and in generally normal, edgewise relationship to the panel member. The support bracket, panel bracket and door bracket cooperate during door opening and closing for permitting lateral door movement generally parallel to the reference plane. The panel bracket and the door bracket may optionally be configured to be interchangeable one with the other.

Abstract: A method of preparing mixtures of dilute acid of varying final specific gravities utilizes microprocessor controlled mixing in two in-line stages. Process recycled or production reject acid or water is initially mixed with concentrated acid and directed to an intermediate heat exchanger for removing the exothermic heat generated during mixing. The specific gravity of the mixture exiting from the heat exchanger is continuously measured and fed to a microprocessor which calculates the deviation between the measured specific gravity and a preselected set point specific gravity which is greater than the desired final specific gravity. The calculated deviation is used to generate a control signal which, in turn, is applied to adjust the flow of concentrated acid until the measured specific gravity corresponds to the set point specific gravity.

Abstract: A motor-driven rotary actuator includes an electric drive motor adapted to be configured for providing one of a plurality of output torques and power transmission means including a rotatable output shaft. The transmission means is coupled to the drive motor and includes drive elements adapted to be formed of disparate materials selected for transmitting one of the output torques. An electric controller is coupled to the motor for providing rotation positioning control of the actuator output shaft in response to analog command signals.

Abstract: An electronically controlled apparatus for controllably positioning pneumatic actuators includes, in a first embodiment, first means for selectively flowing compressed fluid to the actuator and valve means for selectively exhausting compressed fluid from the actuator. An electronic control panel is adapted to receive digital command signals from a computerized controller and is coupled to the first means and to the valve means for actuation thereof in response to the command signals. Means are included for isolating electrical switching transients from the controller.In a second preferred embodiment, the positioner also includes transducer means for generating a feedback signal representative of the position of the actuator piston assembly. A third preferred embodiment is similar to that of the second embodiment and incorporates a control adapted to receive analog rather than digital command signals. An optional high limit pressure switch may be used with any embodiment.

Abstract: A transducer for generating a feedback signal representative of the position of a movable member includes a signal generating mechanism for providing an electrical feedback signal representative of the position of the movable member. The signal generating mechanism includes a first shaft portion having a first longitudinal centerline and a drive mechanism having a shaft member coupled in driving engagement to the first shaft portion. The drive mechanism is adapted to be cable connected to one of a plurality of movable members having maximum travel spans different one from the other. The shaft member has a shaft longitudinal centerline which is concentric with the first centerline, the centerlines defining a first axis. An alignment mechanism is coupled to the drive mechanism and the signal generating mechanism and permits limited movement of the first axis with respect to a reference axis. The alignment mechanism thereby isolates the signal generating mechanism from misalignment reaction forces.