Abstract: A system for controlling refrigerant flow in an air conditioning system employing an electrically operated valve for controlling flow of refrigerant from the condenser to the evaporator. Separate thermistors sense the temperature of the refrigerant entering and discharging from the evaporator. A comparison of the sensed temperatures is used to modify the control signal to the valve for maintaining proper refrigerant flow to the evaporator. A control module is directly attached on the valve body to enhance heat conduction.

Abstract: A system for controlling refrigerant flow in an air conditioning system employing an electrically operated valve for controlling flow of refrigerant from the condenser to the evaporator. Separate thermistors sense the temperature of the refrigerant entering and discharging from the evaporator. A comparison of the sensed temperatures is used to modify the control signal to the valve for maintaining proper refrigerant flow to the evaporator.

Abstract: A refrigeration control system for cooling a vehicle passenger compartment having a compressor/pump for circulating refrigerant between an evaporator located for cooling the compartment air and a condenser located for ambient heat exchange. An expansion valve controls refrigerant flow from the condenser to the evaporator; and, a first thermistor senses directly the temperature of the refrigerant on the high pressure inlet side of the valve and a second thermistor senses refrigerant flow temperature on the low pressure discharge side of the valve. A microprocessor compares the first thermistor output with predetermined first upper and lower values and effects opening and closing of the compressor clutch switch for high pressure cut-off; and, a fan switch is opened and closed for energization and de-energization of a condenser cooling fan.

Abstract: An automotive air conditioning system including an electrically operated expansion valve controlling refrigerant flow to the evaporator. The valve is pressure balanced and provides a minimum flow even when the valve is fully closed. The valve includes a solenoid operator which is energized in a pulse width modulated fashion.

Abstract: A vibration damping device for a thermostatic expansion valve comprises a spring member having a plurality of cantilevered fingers substantially parallel to the direction of travel of moving components but which are spring loaded to provide a force normal to that direction. The damping device is fixedly attached to one of the moving or stationary components and is arranged so that its fingers exert the normal force against the other of the moving or stationary components. Accordingly, a constant magnitude frictional force is produced over the range of movement, thus damping vibrations caused by pressure pulses from the compressor of the refrigeration system in which the thermostatic expansion valve is installed.

Abstract: The electrically operated clutch controlling operation of the compressor is regulated by a damped pressure switch. The pressure switch has a diaphragm which moves in response to pressure variation to actuate the switch. The force acting on the diaphragm is opposed by spring force. The housing is provided with a damping chamber between the diaphragm chamber and the restricted passage in the inlet. The restricted passage is the clearance between the hole drilled in the metal insert and the wire fixed in the hole. The restriction is selected relative to the damping chamber so the switch will not cycle more than four times per minute when sensing pressure at the outlet of a finned coil evaporator in an automotive air conditioning system operating under light load.

Abstract: The inlet and outlet tubes on each side of the valve body are connected to the valve body by a notched plate engaging the shoulder upset from the tube. The upset forms a metal-to-metal seal against the seat in the body while the O-ring engages the wall of the flared section of the inlet leading to the smaller bore which receives the end of the tube.

Abstract: The novelty is the low cost, versatile manner of mounting an evaporator pressure regulator valve (EPR) on a thermostatic expansion valve (TXV) to provide a compact combination valve. The TXV controls refrigerant flow to the evaporator in accordance with the pressure acting below the diaphragm and the temperature influencing the temperature responsive charged space above the diaphragm. The rider pin connecting the diaphragm to the valve is hollowed out so that the bottom of the hole in the rider pin is in the refrigerant return flow path. A restrictor is placed in the upper end of the rider pin to prevent migration of condensed refrigerant to the head chamber in the event the valve is mounted upside down. A sleeve of low thermal conductivity positioned around the rider pin where it passes through the return conduit damps temperature changes and reduces valve hunting. The EPR threads into the TXV outlet.

Abstract: The thermostatic expansion valve has a valve controlling flow from the inlet to the outlet and is biased to seated position by the compressed spring adustably mounted in the outlet. The valve is actuated by a push pin extending from the underside of the diaphragm pad. The diaphragm is mounted between upper and lower stampings welded together at their periphery. The space above the diaphragm is connected via a capillary tube to a feeler bulb and is part of a charged system the pressure of which varies with temperature at the bulb. The lower head stamping is connected to the valve body by novel means. The upper end of the body is provided with a groove receiving an O-ring. Inside this groove the body is provided with an annular extension outside the push pin hole. The lower head stamping is placed on the body and the annular extension is crimped over the stamping to firmly fix the head on the body while devloping high unit pressure on the O-ring to provide an effective seal at low cost.

Abstract: The interior of the bellows is sealed at atmospheric pressure so the pressure on the outside of the bellows is resisted by the atmospheric pressure within the bellows as well as by the spring. When the pressure on the outside of the bellows (which is evaporator pressure in a refrigeration system) exceeds a predetermined amount, the bellows tends to collapse and the head of the bellows pulls away from the actuating pin and allows the spring acting on the pilot valve to open the pilot valve whereupon the pressure to the right of the head of the piston is reduced, allowing the piston to move to the right against the return spring force and thus open the outlet by moving the end of the piston wall past the slot in the stationary sleeve. When the pressure falls below the desired amount, the bellows expands and moves the head of the bellows against the actuating pin to close the pilot valve.