Abstract: A lubricant composition with decreased solubility in a liquid refrigerant and increased foaming characteristics useful in refrigeration systems to promote oil return to a compressor. A lubricant composition comprises a base lubricant, synthetic paraffinic oil, and a foaming agent. These ingredients are blended in predetermined amounts, so that when the lubricant is used in the refrigeration system, an oil rich layer will form atop the liquid refrigerant in the system's flooded evaporator, and a thick, stable foam will form when vaporized refrigerant boils up through the oil rich layer. The oil foam is then drawn through a connection at the top of the flooded evaporator and returned to the compressor.

Abstract: Inside the hermetic shell of a scroll compressor, a normally closed solenoid valve seats against the back side of a stationary scroll plate to close a discharge opening through the plate. A coil circuit that actuates the valve has an electrical resistance that increases with temperature. The temperature dependent resistance allows the coil circuit to also function as a discharge temperature sensor. Should the discharge gas over-heat, the compressor motor and the valve are de-energized in response to the resistance exceeding a predetermined limit. The closed valve prevents backflow from rapidly reversing the rotational direction of the compressor, which can be extremely noisy and damaging to the compressor. Both the valve and the compressor motor are energized at the same time, regardless of the compressor's direction of rotation.

Abstract: A compressor discharge valve assembly including a valve seat, a valve cage, and an annular ring-type valve operating therebetween. The valve cage includes a recess into which the valve retracts when in an open position, or in an alternative embodiment, the valve cage includes a lip portion for shielding the valve. In either embodiment, a reduction in valve flutter and the noise, known as chatter, which results from valve flutter is realized. The valve in alternative embodiments also includes an annular dished portion oriented toward the valve seat for directing the flow of discharge gas smoothly from the compressor and thereby further reducing valve chatter.

Abstract: A compressor driven by a three phase electric motor is contained within a housing that is filled with refrigerant and is hermetically sealed with a terminal board. The terminal board has three electrical feedthrough terminals for coupling three of the motor's six winding leads to a three phase power source. An insulator having a fourth terminal is disposed inside the housing and is attached to one of the feedthrough terminals. In a high voltage application, such as 4160 volts, the fourth terminal provides a convenient location to attach the motor's three remaining leads to a common point. In a low voltage hookup, such as 2400 volts, the fourth terminal is disregarded, and the three remaining leads are separated and paired up with the three leads that are connected to the feedthrough terminals.

Abstract: A screw compressor assembly includes a motor housing section, a compressor section and an oil separator downstream of the compressor discharge port. The motor housing section defines a flow path for suction gas traveling to the working chamber of the compressor so that the compressor drive motor is cooled by suction gas. The motor housing section also internally defines an integral heat exchange structure through which a passage for the flow of oil is defined. Discharge pressure in the oil separator drives separated oil into the passage in the motor housing heat exchange structure prior to the delivery of such oil to compressor surfaces requiring lubrication. The oil flowing through the integral heat exchange structure is cooled by the suction gas passing over the surface of the heat exchange structure interior of the motor housing.

Abstract: An air valve actuated by an electric motor has a cylindrical inlet section. The inlet section defines a seating surface upstream of which is a support grid. A backplate to which the actuating motor is mounted is supported by a plurality of rods that extend downstream of the inlet section. A damper assembly includes a generally planar damper mounted for movement axial of the inlet section. The damper assembly includes a splined rod which extends upstream of the damper and into a cooperating spline in the support grid. A threaded spindle extends downstream of the damper plate through a cooperatively threaded motor-driven drive gear which is mounted for rotation on the backplate. Because a portion of the damper assembly is splined, the damper assembly cannot rotate and is driven axially within the valve by the rotation of the drive motor and drive gear.

Abstract: A rectangular damper blade rotates about its longitudinal center line between an open and closed position to control the airflow entering an enclosure. Two longitudinal edges of the damper blade become positioned between two inlet edges of the enclosure as the blade rotates to the closed position. The blade is associated with two longitudinal seals. One seal is attached directly to one of the blade's longitudinal edges and provides wiping contact against one of the inlet edges. The other seal is attached to the other inlet edge and provides wiping contact against the blade's other longitudinal edge. Both seals have similar cross-sections to facilitate their interchangeability. And both seals include a flexible lip that extends upstream and perpendicular to the blade to enhance the sealing force and to minimize wiping friction.

Abstract: A body located downstream of the compressor discharge port in an oil-injected screw compressor assembly includes a contoured surface for directing the flow of the gas-oil mixture discharged from the compressor. The body is movable in the compressor assembly between a first position in which the flow of the mixture out of the discharge port is unimpeded and a second position in which the backflow of gas from downstream of the discharge port back into and through the working chamber of the compressor is prevented. In the first position the body facilitates the separation of oil from the discharged compressed gas while in the second position the reverse direction rotation of the screw rotors in the compressor working chamber is prevented.

Abstract: An outdoor enclosure for air handling equipment is adaptable to accept add-on air handling equipment by virtue of a two-position cover panel. The cover panel has a generally rectangular shape and is attached to a side panel of the enclosure. The cover panel is selectively mountable in either a vertical position to cover a fresh air opening through the side panel or in an open position to uncover the opening. The cover is opened by pivoting it about its upper horizontal edge which is located just above the opening and swinging its lower edge outwardly away from the side panel. An add-on mist elimination filter is installed in a generally horizontal position betweeen the cover panel's lower edge and the lower edge of the side panel's opening. In the open position, the cover panel serves as a rain sheltering hood over the filter while the opening allows fresh outside air to be drawn into the suction side of a fan located inside the enclosure.

Abstract: A method for vaporizing the refrigerant trapped in the oil reservoir of a hermetic compressor. The refrigerant is vaporized by heat from a small pill shaped PTC heater (positive temperature coefficient heater) simply attached with adhesive tape in a shallow depression disposed near the bottom of the reservoir. The depression, formed on the compressor shell as a seamless indentation, extends into the reservoir and has a concave shape that conforms to the external surface of the heater. This provides a strong and hermetically sealed integral heater fixture having close fitting heat conductive contact with its associated heater element. The heater, being disposed in the shallow indentation, is placed in more direct contact with the liquid refrigerant, which tends to settle at the bottom of the reservoir due to its density being greater than that of the oil.

Abstract: A flue gas/combustion air heat exchanger for a furnace. The furnace includes a combustion chamber that burns a mixture of fuel and combustion air to produce heat for a comfort zone. The resulting products of combustion, along with any waste heat not transferred to the zone, pass through a flue duct before venting to atmosphere. Incoming combustion air is discharged across the relatively hot flue duct before it enters the combustion chamber. In passing across the hot flue duct, the incoming air is preheated by waste heat of the combustion products. The heat exchange relation between the incoming combustion air and the combustion products within the flue duct enables the furnace to recover waste heat that would otherwise be lost if the combustion products were free to discharge to atmosphere before giving up a portion of their waste heat to the incoming combustion air.

Abstract: A microcomputer based fault detector for identifying a phase reversal, a phase loss, and a power loss in three-phase circuits. A microcomputer samples a pattern of timing signals generated in response to three current transformers associated with each of the three phases. The changing pattern of timing signals represent the phase relationship of each of the three phases. The sampling rate of the microcomputer is synchronized to the alternating current in each of the three phases by an interrupt signal indirectly generated by one of the phases. In the absence of current in this interrupt generating phase, a backup interrupt, internal to the microcomputer, is enabled which directs the microcomputer to determine if the absence of the first interrupt is due to a phase loss or a power loss. Either interrupt prompts the microcomputer to sample the pattern of signals and compare it to a predetermined pattern.

Abstract: A refrigeration system has multiple compressors in a parallel arrangement. The pressures in the shells of operating compressors are maintained equal by the controlled delivery of suction gas and entrained oil to the shells of individual operating compressors in quantities which maintain the pressures therein equal. A valve, directly responsive to compressor shell pressures, occludes the flow of suction gas to the shell of an operating compressor in which the pressure is greater than that found in the shell of another operating compressor so as to equalize the pressures in the compressor shells. The equalizing valve arrangement directs and apportions essentially the entire amount of suction gas to the shells of operating compressors while cutting off the flow of suction gas into the shells of non-operating compressors.

Abstract: A normally open pneumatic air control valve includes an inlet section which defines a seating surface and a support grid. A support plate, located downstream of the inlet section, is itself supported by a plurality of rods extending from the inlet section. A damper assembly is disposed for movement axial of the inlet section and is supported for such movement between the inlet section support grid and the downstream support plate. The damper assembly is actuated by the admission of a pressurized gas to a chamber cooperatively defined by a housing fixed to the support plate and a diaphragm disposed therein. A spring acts on the fixed grid support of the inlet section and on the damper assembly to urge the damper assembly away from the inlet section so that the valve is biased to the open position.

Abstract: A normally closed pneumatically actuated air valve for use in a variable air volume air distribution system has a unitary inlet section which supports a damper assembly and actuator through a support grid disposed in the inlet section. The damper assembly is mounted for axial movement, on a fixed spindle and guide piston, under the impetus of the expansion of a pressure chamber defined by a portion of the damper assembly and a diaphragm which conformably surrounds the guide piston. A biasing spring acts on a surface of the fixed guide piston and on the damper assembly to bias the damper assembly toward a seating surface of the inlet section.

Abstract: A frameless air handling enclosure is made possible by the use of double-flanged edges on the enclosure's side and bottom panels. The edge configuration provides reinforcement and rigidity to an otherwise flexible panel and also provides a mating surface for fastening the panels together. The enclosure includes an access opening that is covered by a removable access panel having a lining of sound and thermal insulating material. The access panel is installed by first sliding it upward into engagement with a top flange retainer and then sliding it back down into engagement with a bottom flange retainer. Upon engagement with both flange retainers, the lining of insulation is compressed against the perimeter of the access opening. This compression fit not only helps hold the access panel firmly in place but also provides a weathertight seal around the perimeter of the opening.

Abstract: In a system with parallel connected compressors, a suction and discharge manifold arrangement for isolating an inactive compressor from the rest of the operating system. A check valve in the discharge line of the compressor prevents fluid flow back into the discharge port from a common system discharge line when the compressor is de-energized. A normally closed, pressure actuated valve in the suction line of each compressor prevents fluid from flowing through the compressor suction port when the compressor is inactive. The valve is connected to the compressor's discharge line, and opens in response to the discharge pressure developed when the compressor begins to operate. Pressure and oil level equalizing lines interconnect the compressor oil sumps, conveying oil between compressors and equalizing pressure in the oil sumps.

Abstract: A device for mounting a thermal overload protector to the motor of a hermetic refrigeration compressor. The overload protector is temperature responsive and is operative to protectively interrupt the current to the motor when the stator windings, rotor, or other heat source in the compressor overheats due to a compressor overload. The protector's mounting device is a plastic receptacle having a shield connected by an integral hinge. The hinge not only facilitates manufacturing the receptacle as a unitary part by an injection molding process, but also enables the shield to be opened for inserting the overload protector into the receptacle. The overload protector is held firmly in place by a U-shaped bracket integrally disposed inside the receptacle. A U-shaped groove runs along the inner edge of the bracket and is designed to slidingly engage protectors of various shapes. The receptacle includes an opening on one side of the protector opposite the heat retaining shield.