Abstract: A refrigerant system includes a compressor with a discharge valve that temporarily restricts the compressor's outflow at startup so that the discharge pressure can quickly rise to force lubricant back to the compressor. The discharge valve also helps prevent an axial face of a rotor of a screw compressor from rubbing against a bearing housing axial face of the compressor's housing. When the system turns off under certain low ambient air temperature conditions, the valve closes to help prevent the system's evaporator from freezing up. The discharge valve includes a novel arrangement of a piston, a valve stem extending from the piston, and a valve plug pivotally attached to the valve stem. The pivotal connection ensures a positive seal between the valve plug and a valve seat. A somewhat restricted fluid passageway between the valve's discharge chamber and piston chamber helps prevent the valve from chattering as the valve opens.

Abstract: A refrigerant system includes a compressor with a discharge valve that temporarily restricts the compressor's outflow at startup so that the discharge pressure can quickly rise to force lubricant back to the compressor. The discharge valve also helps prevent an axial face of a rotor of a screw compressor from rubbing against a bearing housing axial face of the compressor's housing. When the system turns off under certain low ambient air temperature conditions, the valve closes to help prevent the system's evaporator from freezing up. The discharge valve includes a novel arrangement of a piston, a valve stem extending from the piston, and a valve plug pivotally attached to the valve stem. The pivotal connection ensures a positive seal between the valve plug and a valve seat. A somewhat restricted fluid passageway between the valve's discharge chamber and piston chamber helps prevent the valve from chattering as the valve opens.

Abstract: A protection system for a compressor. The system comprises a compressor having a discharge and including at least one rotor and at least one bearing; a lubrication system including at least one oil recovery device for recovering oil from the compressor, and further including bearing conduit connecting the oil recovery device to the compressor bearing and including rotor conduit for connecting the oil recovery device to the compressor rotors; and an oil protection system. The oil protection system includes a compressor discharge temperature sensor located in the discharge for sensing the temperature of a lubricant/refrigerant mixture discharged by the compressor, a differential pressure sensor located in the bearing conduit for measuring a differential pressure in the bearing conduit, and an oil detector located in the rotor conduit for detecting the presence of oil in the rotor conduit.

Abstract: The position of a slide valve in a screw compressor in a refrigeration system is controlled using a gaseous medium sourced from two or more sources of such fluid, both of which are in open flow communication with the slide valve actuating piston when the slide valve load solenoid is open. Preferred gas sources are a closed compression pocket in the working chamber of the compressor and the discharge passage downstream of the compressor's working chamber. Gas at sufficiently high pressure is available whenever the compressor is operating to ensure that the compressor will load under all conditions within the compressor's operating envelope.

Abstract: A low side scroll compressor is protected from both the potentially damaging effects of improper electrical hookup and the development of high discharge temperatures by the disposition of a valve member in a passage which communicates between the suction pressure portion and a discharge pressure portion of the compressor. The valve operates to permit the flow of gas from the suction to the discharge pressure portion of the compressor through a protective passage when the compressor is caused to run backwards due to miswiring so as to avert damage to the scroll members. The valve permits the flow of gas from the discharge to the suction pressure portion of the compressor through the protective passage when the temperature of the discharge gas produced by the compressor is caused to exceed a predetermined temperature. The resulting flow causes the compressor motor to de-energize.

Abstract: In a rotary compressor, a relief valve for providing refrigerant at suction gas pressure to the discharg port when the rotary compressor is operated in the reverse rotation direction. The relief valve includes in the preferred embodiment a passage for providing a source of refrigerant at suction pressure, a pressure responsive relief valve, and a passage for providing refrigerant at suction pressure from the relief valve to the discharge port. When the compressor system is operated in the correct rotation, refrigerant at discharge pressure maintains the relief valve in the closed position, preventing flow from the discharge port to the suction pressure source. When the compressor system is operated in the reverse rotation however, the pressure in the discharge port is reduced to below that of the refrigerant in the suction pressure source, whereupon the releif valve opens permitting flow from the suction pressure source to the discharge port.