Abstract: An optically based liquid level (liquid-vapor) detector for use with a window having a substantially planar side facing the liquid-vapor side and a substantially planar side positioned parallel to the liquid-vapor side facing the outside. The detector comprises a light source positioned on the outside of the window to direct its light through the outside planar side to the inside planar liquid-vapor side and a light detector positioned on the outside of the window to receive light transmitted from the source and returned from the planar liquid-vapor window side. The detector further includes electronic means for detecting the light intensity change affecting the transducer, from the condition of liquid on the liquid-vapor side, to the condition of vapor on the liquid-vapor side of the window, whereby an action or signal is generated in response to such change.

Abstract: An optically based liquid level (liquid-vapor) detector for use with a window having a substantially planar side facing the liquid-vapor side and a substantially planar side positioned parallel to the liquid-vapor side facing the outside. The detector comprises a light source positioned on the outside of the window to direct its light through the outside planar side to the inside planar liquid-vapor side and a light detector positioned on the outside of the window to receive light transmitted from the source and returned from the planar liquid-vapor window side. The detector further includes electronic means for detecting the light intensity change affecting the transducer, from the condition of liquid on the liquid-vapor side, to the condition of vapor on the liquid-vapor side of the window, whereby an action or signal is generated in response to such change.

Abstract: A floodback detector for refrigerant systems employing any of: minimum suction temperature, temperature rate of change and duration thereof; minimum superheat, superheat rate of change and duration thereof.

Abstract: A non-fouling liquid level detector and control especially for a sealed system likely to have iron particle contaminants. The device employs a float projecting above the liquid level and bearing above the liquid level a unmagnetized ferromagnetic tell-tale. A magnetic field is generated by a magnet positioned outside the sealed system. The magnetic field extends around the float and tell-tale through a magnetically permeable partition comprising a wall of the sealed system that is positioned between the magnet and the float. The float position is monitored by a magnetic field sensor such as a Hall Effect device positioned adjacent the magnet, outside the sealed system. The sensor responds to the movement of the tell-tale. The output of the sensor is employed to control the monitored liquid level.

Abstract: A protective construction for a piezo-resistive silicon pressure transducer intended for connection to a pressure source that exhibits pressure transients. The construction includes the transducer, a conduit for providing pressure communication between the pressure source and the transducer and a flow restrictive device positioned within the conduit.

Abstract: An optical liquid level sensor for distinguishing between the presence of oil and vapor within a compressor crankcase. The sensor has a light transmitting window positioned to interface the crankcase interior and a planar side facing the crankcase exterior. A light source and a light sensor are both positioned adjacent the exterior face of the window. The sensor has a first condition when the prismatic face is immersed in oil and a second condition when the prismatic face is immersed in vapor. An electronic circuit having a dual MOSFET switch for alternating current is mounted adjacent the light source and sensor. The circuit provides power to the source and monitors the sensor. When the sensor is in the first condition, the circuit closes the switch. When the sensor detects the second condition, the circuit starts a timer and continuously tests the condition of the sensor. If the first condition is detected, the timer resets to its initial value.

Abstract: A gage having sensors for observing temperature and pressure. The gage includes a display and an internal computer. A data cartridge separate from the gage but with an electrical plug type connection to it is supplied. The data cartridge has a non-volatile memory on which is stored data relating pressure and saturation temperature of a volatile refrigerant. A program is stored within the gage. The program contains instructions for measuring temperature and pressure from a source, retrieving from the data cartridge saturated temperature data corresponding to the observed pressure, calculating superheat or subcooling and displaying in sequence the observed pressure in absolute or gage terms, the corresponding saturated temperature, the observed temperature and the superheat or subcooling.

Abstract: An optical sensor, having serviceable electronics, for monitoring the level of a liquid within a vessel having an exterior and an interior and for providing an electrical signal on the traverse of the liquid level past the sensor. The sensor comprises a fitting adapted to traverse the vessel wall, the fitting including a window having a prism shaped interior face and a planar exterior face sealed into the fitting and providing a fluid-tight optical path from the vessel interior to the vessel exterior. The fitting includes a chamber adjacent the planar face of the window and an electronic module shaped to fit the chamber. The module has an optical face. A light source and a light detector are positioned in the optical face to provide substantially zero clearance light communication between the window and both the source and the sensor, when the module is positioned within the chamber.

Abstract: An oil level sensor device for sensing and controlling the level of oil in the crankcases of refrigeration compressors, each compressor having a crankcase with a housing for oil that accumulates during the compression operation and each housing having an opening with a prism member mounted in it, the prism members having two angularly relating surfaces exposed to the oil in the crankcase and a light source and a light sensor mounted adjacent to the prism on the outside of the crankcase housing such that the light from each light source impinges on one of the angularly related prism surfaces and is reflected thereby to the second angularly related surface and then back to the light sensor. Each light sensor has an output which is connected to the input of the control circuit which operates to energize a solenoid valve to add oil to the crankcase from a remote source when the oil level in the crankcase as sensed is below a predetermined level.

Abstract: A bubble detector for a liquid stream flowing within a conduit comprising a walled chamber communicating with the conduit interior, the chamber being positioned to trap and accumulate bubbles entrained with the liquid stream. A window in the chamber wall for optically examining the chamber, the window having its inner surface positioned to provide an interface with the chamber contents. Means for distinguishing between liquid and gas in the chamber comprising a light source positioned to direct its light toward the window inner surface, and a light sensor oriented to receive light reflected from the window inner surface the light source being positioned at such angle to the window inner surface that transmission of light with refraction occurs when liquid is present in the chamber and total internal reflection occurs when gas is present in the chamber. And an output device responding to the sensor for taking an action when a predetermined volume of bubbles have accumulated in the chamber.

Abstract: An improved capacitance bridge type liquid level control system for use in refrigeration applications is disclosed which provides improved apparatus for sealing the probe in its mounting and for insulating same against the condenser reservoir stand pipe in which it is mounted. Improved sealing between the probe and probe body is accomplished through an annular PTFE seal which when compressed pushes inwardly to seal a tubular PTFE insulation against annular ridges in the side of the probe rod proper. The improved probe rod shape also maintains a proper stabilized axial alignment between the probe rod and the probe body.

Abstract: In a refrigeration system there is provided a main valve that has its inlet port fluidly connected to an evaporator while its outlet port is fluidly connected to the suction port of a motor-compressor. The closing of the main valve is controlled by an auxiliary valve, the auxiliary valve being connected in an auxiliary line that at one end opens to the gas port of a condenser or to a line between the condenser and the motor compressor. The auxiliary valve is connected in the auxiliary line in series with a fixed throttle and is downstream of the throttle. The closure member of the auxiliary valve opens on an increase in the evaporator pressure. A check valve, for example a two way magnetic valve, is connected between the auxiliary valve and the suction port.

Abstract: An improved capacitance bridge type liquid level control system for use in refrigeration applications is disclosed which provides improved apparatus for sealing the probe in its mounting and for insulating same against the condenser reservoir stand pipe in which it is mounted. Improved sealing between the probe and probe body is accomplished through an annular PTFE seal which when compressed pushes inwardly to seal a tubular PTFE insulation against annular ridges in the side of the probe rod proper. The improved probe rod shape also maintains a proper stabilized axial alignment between the probe rod and the probe body.

Abstract: A refrigeration control system for modulating an electrically-operated expansion valve in which a modulating, electrically-operated expansion valve is connected to the evaporator inlet, and first and second condition-responsive electrical sensors are positioned to respond to conditions at selected location in the system. An electrical amplifier circuit connects the condition-responsive electrical sensors to the valve for regulating the opening and closing of the valve in response to differences in the conditions sensed by the sensors. Refrigerant is fed to at least one of the sensors so as to cause modulation of the expansion valve. More particularly, the condition-responsive sensors are temperature-responsive, the first sensor being positioned to respond to the temperature of the liquid refrigerant expanded to suction pressure, and the second sensor being positioned to respond to suction line sensible temperature.

Abstract: A pilot-operated pressured regulator valve includes a main valve for controlling refrigerant flow in a refrigeration suction line. A pilot valve which is responsive to evaporator pressure controls a flow of high pressure refrigerant to the main valve for modulating the main valve. A bleed is provided for bleeding the high pressure refrigerant from the main valve. A solenoid-actuated shut-off valve controls the bleed flow from the main valve. The shut-off valve is selectively closed for maintaining the high pressure refrigerant in the main valve for closing the main valve. A bleed flow of high pressure is provided to the main valve when the shut-off valve is closed in order to maintain the main valve closed.

Abstract: A refrigeration control system for modulating an electrically-operated expansion valve in which a modulating, electrically-operated expansion valve is connected to the evaporator inlet, and first and second condition-responsive electrical sensors are positioned to respond to conditions at selected location in the system. An electrical amplifier circuit connects the condition-responsive electrical sensors to the valve for regulating the opening and closing of the valve in response to differences in the conditions sensed by the sensors. Refrigerant is fed to at least one of the sensors so as to cause modulation of the expansion valve. More particularly, the condition-responsive sensors are temperature-responsive, the first sensor being positioned to respond to the temperature of the liquid refrigerant expanded to suction pressure, and the second sensor being positioned to respond to suction line sensible temperature.

Abstract: A refrigeration control system for modulating an electrically-operated expansion valve in which a modulating, electrically-operated expansion valve is connected to the evaporator inlet, and first and second condition-responsive electrical sensors are positioned to respond to conditions at selected location in the system. An electrical amplifier circuit connects the condition-responsive electrical sensors to the valve for regulating the opening and closing of the valve in response to differences in the conditions sensed by the sensors. Refrigerant is fed to at least one of the sensors so as to cause modulation of the expansion valve. More particularly, the condition-responsive sensors are temperature-responsive, the first sensor being positioned to respond to the temperature of the liquid refrigerant expanded to suction pressure, and the second sensor being positioned to respond to suction line sensible temperature.