Abstract: A sensor and control module have a housing with an internally mounted printed circuit board which supports a sensing element located in an outwardly projecting hollow portion formed at the lower part of the housing. The projecting portion is prism-shaped and includes air intake slots at its bottom side to enable external air to reach the element. The upper side of the projecting portion which is adjacent to control elements on the module is sealed. The housing is provided with an internal air passage adjacent to the printed circuit board between the air intake slots and air exit slots at a top side of the housing spaced from the control elements. In one embodiment, the module is a thermostat, and the sensing element is a temperature responsive resistor used to sense air temperature.
Abstract: A liquid level sensor comprises a light source in the form of a semiconductor device, a light sensor also in the form of a semiconductor device, and an optical element arranged to transmit light from the light source and to receive reflected light and transmit it to the light sensor, the liquid level sensor further comprising a carrier having gas-filled cavities means in which the light source and the light source and the light sensor are respectively mounted, the cavities being separated by barrier means to prevent scattered light reaching the light sensor from the light source. The mounting of the light source and light sensor in gas-filled cavities extends significantly the operating temperature range of the liquid level sensor.
Abstract: A method of making a current sensor device is disclosed wherein a sensor, having a magnetoresistive element configured into a bridge, an insulating substrate and a conductive member are sub-assembled and then the sub-assembly is heated to bond the components together. The bridge is attached to a first substrate having a first layer of insulation with first vias therein in which are deposited first elements of solder projecting beyond the first layer of insulation. Second elements of (e.g.) solder are deposited in second vias in a second layer of insulation on the second substrate. When the components are sub-assembled, the first elements rest on the second elements to provide a clearance between the first and second layers of insulation.
Abstract: Apparatus for control of the range of input voltage values to be measured and for compensation of the changes in the supply voltage of an analog to digital dual slope converter circuit is described. The selection of a range for input voltage measurements in the analog to digital converter circuit permits the conversion to take place over a relatively long time period, thereby increasing the resolution of the resulting conversion. Changes in the supply voltage are combined with the input analog signal (during the capacitance charging period) and with the reference voltage (during the capacitance discharge cycle) providing compensation for the effects of time, temperature and the tolerance of the supply voltage.
Abstract: A method for improving cooling of a compressor element used in an air conditioning system and having a refrigerant compressor and associated drive motor hermetically sealed in a fluid-tight shell includes the steps of detecting an excessive increase in the temperature of the compressor element, intermittently operating the system during the excessive temperature detection with a superheat of a refrigerant in the system below zero superheat degrees to concurrently allow liquid refrigerant to enter the shell to enhance the cooling of the compressor apparatus by the latent heat of vaporization of the liquid refrigerant and terminating the intermittent operation and the admittance of the liquid refrigerant into the compressor element upon a detection of a desired temperature of operation of the compressor element.
Abstract: A control for the indoor air circulating fan of a heat pump when the heat pump is operating in the heating mode. After the compressor starts, the control delays the operation of the indoor fan if the temperature is below a predetermined reference temperature. The delay time increases as the outdoor temperature decreases.
Abstract: A printed circuit board mounted rotary electrical switch has a rotatable electrical contact carrier mounted for rotation within a cup-shaped housing and carrying indexing and rotation limiting devices cooperating with the housing. An electrical contact strip is carried by the rotatable carrier for selectively providing a direct electrically conductive bridge between pairs of a plurality of projecting electrical contacts attached to the circuit board and to corresponding printed wiring on the circuit board. The housing is attached to the circuit board by screws threaded into the circuit board through perforated ears projecting from respective sides of the housing. The carrier and the housing are made of an electrically non-conductive material to protect the strip and the contacts from extraneous electrical paths.
Abstract: A refrigeration system comprises a compressor, a condenser, an evaporator, an accumulator, and an adjustable controllable expansion valve. An electronic control system monitors the value of superheat and accordingly provides an electrical control signal to adjust the controllable expansion valve in order to maintain a set point superheat value. An unfiltered path is provided to ensure expedient response when the system starts operation and when dynamic changes occur. A filtered path is provided to reduce hunting, or oscillations about the set point, of the superheat value during steady state operation.
Abstract: An electro-pneumatic transducer comprises a moving coil supported by the baffle plate covering a nozzle with the baffle plate consisting of a disk spring being concentrically arranged with respect to the nozzle.
Abstract: A temperature conditioning system has a temperature conditioning apparatus such as a heating apparatus or cooling apparatus, an air treatment for cleaning apparatus and a fan for moving air through the temperature conditioning apparatus and air treatment apparatus to supply the conditioning air to a space in which the temperature is controlled by a space thermostat connected to control the heating and cooling apparatuses. The space thermostat has a switch connected through a fan cycler to provide for cycling the fan independent of the operation of the heating and/or cooling apparatus to periodically move air through the air treatment apparatus and throughout the space to insure that the air is periodically treated and moved throughout the space to prevent stagnation when there is no call for operation of the heating and/or cooling apparatus.
Abstract: A compensation circuit for sensor lag uses a sensor temperature signal modification circuit to provide a modified sensor temperature signal for subsequent use in controlling the sensed temperature. The compensation circuit digitally compares a current sensor temperature representative signal and a sensor temperature signal at a last or preceeding sample time to produce a difference signal which is converted to a sensor slope signal and is multiplied by a sensor time constant. The resulting signal is passed through a filter to eliminate transient effects and is summed with the original sensor temperature signal to provide a sensed temperature signal for control of the temperature whereby the sensed temperature is a better estimate of the actual environmental temperature controlled by a thermostat utilizing the sensed temperature signal.
Abstract: For determining the charging of a charcoal filter with gases and vapors the acoustical and the electrical impedance of the charcoal layer are measured. The more the filter is charged the greater will be the density of the charcoal layer and therewith its acoustical conductivity. The charging of a charcoal layer with water vapor results in an increase of the acoustical as well as of the electrical conductivity. By comparing the acoustical impedance and the electrical impedance respectively of a partially charged charcoal layer with the impedance of a non-charged charcoal layer and by subsequent comparison of the impedance changes caused by such charging the influence of water vapor can be eliminated. A signal is generated corresponding to the charging of the charcoal filter with other vapors and gases which signal may be used for indicating the condition of the filter and for generating an alarm if the filter becomes exhausted.
Abstract: A method of manufacturing wherein a first metal member is installed into a second metal member is disclosed. The first metal member is punched out of a stock into the second metal member which extrudes a slug. The combination is then placed over a flat surface and a second larger punch is applied to cause the slug to reflow back up into its original structure, but with that reflow crimping the first metal member that was punched out into a permanently attached place within the second metal member.
Abstract: A slow opening and fast closing gas valve includes a valve seat and a valve closure member arranged to respond to a gas pressure to seal aganst the valve seat to close the valve to an input gas flow therethrough. In order to open the valve, the gas exerting the gas pressure for sealing the valve closure member against the valve seat is allowed to bleed-off through a fixed restriction while the input gas is allowed to urge the valve closure member away from the valve seat to provide a slow opening of the input gas flow path through the valve. In order to close the input gas path through the valve, the input gas pressure is applied to the valve closure member to assist a closure spring in urging the valve closure member against the valve seat to produce a fast closure of the valve. A second valve is arranged to selectively control the flow path of the gas being bled off from the valve closure member to provide an unrestricted flow path or a restricted flow path through the fixed restriction.
Abstract: A refrigeration system control for minimizing cycling losses of a refrigeration system having an indoor coil, an indoor coil fan, an outdoor coil, an outdoor coil fan, a refrigerant line between one end of the indoor coil and one end of the outdoor coil, a compressor apparatus and a reversing valve connecting the compressor apparatus between the other end of the indoor coil and the other end of the outdoor coil includes the steps of operating the reversing valve to a state opposite to the one representative of the operating condition of the refrigeration system for a predetermined period of time starting prior to an energization of the compressor apparatus and ending after the energization of the compressor apparatus, restoring the reversing valve to a state needed for the operating condition of the refrigeration system at the end of the period of time while continuing the energization of the compressor apparatus.
Abstract: A switch operator has a low friction ratchet wheel driven by a low power time programmed clock to operate the switch in one position or another depending upon the position of the ratchet wheel to operate the ratchet wheel independent of the time programmed clock. A pawl resiliently held and biased away from the ratchet wheel engages the ratchet wheel when moving in a forward direction to move it a predetermined amount. A cam member mounted adjacent the ratch wheel is engaged by the pawl to bias the pawl against a projection on the ratchet wheel when the pawl is moved forward and to bias the pawl away from the ratchet wheel upon its return movement.
Abstract: For passive range metering of moving vehicles a receiver is used having two detectors spaced apart and directed to the path of the vehicle which moves with constant speed and the length of which is known. The receiver measures the pass-through time of the image of the vehicle through the first detector and furthermore measures the traveling time of the image of the vehicle from one detector to the other. The distance E can be calculated by equation ##EQU1## wherein f is the focal distance of the receiver optics, Q.sub.t is the quotient of the measured time values, l is the length of the vehicle.
Abstract: A method of communicating data between first and second communication apparatus having the steps of transmitting line current from the first communication apparatus to a transmission line interconnecting the first and second communication apparatus, the line current being controlled at an analog value representing analog data and having superimposed thereon a digital signal representing digital data, receiving at the second communication apparatus the analog and digital data transmitted by the first communication apparatus, controlling the transmission line voltage at an analog value for transmitting analog data from the second communication apparatus to the first communication apparatus and superimposing on the voltage containing the analog data a digital signal representing digital data, and receiving at the first communication apparatus the analog and digital data transmitted by the second communication apparatus.