Abstract: In a refrigeration system including a compressor, a condenser exposed to a cooling medium for causing condensation of the refrigerant within the refrigeration system and an apparatus for controlling the flow of the cooling medium, a control method and apparatus for operating the flow control apparatus in response to suction pressure or suction temperature as sensed at the compressor. In an exemplary system utilizing air as the cooling medium and a fan for causing airflow, the fan is started after compressor start-up when sensed suction pressure rises above a predetermined amount. An additional feature includes an adaptive time limited compressor cut-out protection for low ambient temperature operation.

Abstract: A capillary tube assembly having a capillary tube body for connection to a refrigeration system and a tube end cap for accepting a plurality of capillary tubes each of which is identically preformed. The capillary tube assembly is adaptable to different refrigeration systems of varying capacity by utilizing a suitable number of identically preformed capillary tubes together with a suitable tube end cap. The capillary tube assembly is manufactured by preforming identically a suitable number of capillary tubes, preparing a tube end cap with the desired number of apertures and inserting therethrough the capillary tubes, securing the tube end cap to a capillary tube body and reducing the diameter of the tube body to the diameter of the refrigerant supply line of the refrigeration system to which the capillary tube assembly is to be applied.

Abstract: An electrically actuated valve for incremental fluid flow rate control is disclosed. The valve is comprised of a valve body having an interior with a planar outlet surface against which a rectilinear valve element is slidingly operated. The valve body includes an inlet orifice and an outlet orifice in the planar outlet surface for fluid flow through the valve body. The valve element has an orifice therethrough controlling flow through the outlet orifice in accordance with the position of the valve element, which is linearly actuated by a rotary stepper motor.

Abstract: In a scroll compression apparatus having an orbiting scroll, a frame with a pressure regulation chamber adjacent the orbiting scroll wherein the frame includes a spring biased annular seal and a pressure responsive device in a discharge aperture through the frame for maintaining constant pressure in the pressure regulation chamber. Preferably, the frame includes an annular groove of rectangular cross-section accommodating a relatively smaller annular seal also of rectangular cross-section. An annular seal spring having a first planar surface and a second planar surface is disposed in the annular channel to bias the annular seal. The pressure responsive device has a first element exposed to discharge fluid pressure and a second element exposed to fluid at suction pressure such that the pressure differential serves to operate a piston for increasing or decreasing the flow area of the discharge aperture from the pressure regulation chamber.

Abstract: In a co-rotating scroll apparatus wherein one scroll is a drive scroll and the other scroll is an idler scroll, an axial pressure balancing mechanism and means for discharge pressure balancing is disclosed. The drive scroll wrap is provided with an end plate having a plurality of extension members extending thereform. The extension members extend through corresponding slots in an Oldham coupling ring to drive the idler scroll in relative orbital rotation. The extension members further extend through clearance slots in the end plate of the idler scroll to secure a compression plate and spring biasing the end plate of the idler scroll toward the drive scroll to provide improved axial compliance between the scrolls. Means for axial pressure balancing of the idler scroll shaft and the drive scroll drive shaft are disclosed. The apparatus also includes axial thrust bearings for preventing axial oscillations of the drive and idler scrolls.

Abstract: A tube arrangement for a tube-type heat exchanger. The tube arrangement provides for the location of the tubes in the upper portion of the drum defining the combustion chamber of the heat exchanger. In one embodiment, four heat exchange tubes are provided, with two of the tubes disposed such that the axial center line of the tube lies across the horizontal center line of the heat exchanger drum, and with two tubes disposed entirely above the horizontal center line of the drum.

Abstract: In a compressor of the hermetic, scroll-type, a motor engaging drive shaft having a net axial thrust load determined by the pressure of compressed fluid acting upon the opposing ends of the shaft. In the preferred embodiment, the shaft includes a first end in the discharge pressure portion providing a first plan view area and a second end in the suction pressure portion having a circular, eccentrically disposed cavity with a second plan view area. The shaft has an axial bore for communicating refrigerant at discharge pressure through the shaft between the respective ends such that refrigerant at discharge pressure acts in opposite directions upon both of the respective plan view areas to balance the net thrust load of the shaft.

Abstract: A variable capacity refrigeration system includes a control scheme having three interrelated closed loops. The system includes a refrigeration system controller and at least one variable speed, electronically commutated DC motor driving a compressor. In the first closed loop, the controller supplies a speed command signal to a motor drive which governs the speed of the motor driven compressor. The speed of the compressor varies the system's capacity to condition the temperature of a comfort zone. A temperature sensor in the zone provides a temperature feedback signal to the controller to complete the first closed loop. In the second closed loop, the speed command signal from the controller is varied in response to a speed feedback signal received from a compressor drive which includes both the motor and the motor drive. The third closed loop is between the motor drive and the motor.

Abstract: A method of controlling a refrigeration compressor involves momentarily energizing the compressor after extended off periods. When the temperature of a comfort zone remains below its set point temperature for an extended period, such as at night, periodically energizing the compressor for brief periods improves the confort level of the zone.

Abstract: An economizer for an air handler, air conditioner or similar unit. The economizer has a first position and a second position. In the first position, the economizer is retracted and presents a relatively flat end surface of the air handler, and in a second position the economizer projects from the air handler and provides for the intake of ambient air into the air handler. The invention provides for the shipment of the economizer intact with the air handler so that installation of the unit is conveniently achieved.

Abstract: Apparatus and method for selectively determining the resonant frequency of a gas compressor including a compressor drive motor and a muffler in a generally spaced relationship, and an apparatus mechanically linking the compressor drive motor and the muffler. The apparatus as disclosed in one embodiment includes two conical frustums as wedge members, each having an axial bore accommodating a single non-resilient shaft for joining the conical frustums such that the shaft may be adjusted to force the wedge members closer together, biasing the muffler with respect to the compressor drive motor, and thereby adjusting the resonant frequency of the compressor structure to a determined resonant frequency.

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.

Abstract: In an island type refrigeration display cabinet, a top aperture containing two oppositely disposed louvers for discharging oppositely directed coplanar air curtain sections, to form a single air curtain of multiple section in the top aperture of the display cabinet. Preferably, the cabinet also includes means for withdrawing air from the interior display space of the cabinet and forcing the air through a bifurcated conduit. Each bifurcation of the conduit is flowably connected to one of the respective louvers in the top opening of the display cabinet. Each bifurcation of the conduit also includes means for refrigerating the air flowing through the conduit to the louvers.

Abstract: A solenoid valve used as an expansion valve in a refrigeration circuit has an opening that varies as a function of the pulse width of a high frequency PWM (pulse width modulated) control signal. A transistor controls the electrical current delivered to the solenoid valve. The PWM control signal rapidly cycles the transistor on and off at a constant frequency that is sufficiently high to prevent the valve from having enough time within a cycle to move between fully open and closed. As a result, the valve balances at an intermediate position determined by the relative lengths of the on and off periods of each pulse cycle. The relative on-off pulse widths, often referred to as, "duty cycle", is varied in response to a temperature sensor to control the flow of refrigerant through the refrigeration circuit. The duty cycle is also adjusted to compensate for any variations in the supploy voltage applied across the solenoid valve.

Abstract: The variable opening of a pressure independent supply air valve for a building ventilation system is controlled in response to a standard airflow transducer whose output is modified to emulate a close tolerance transducer. In a calibration mode, a microcomputer based control closes the valve and a summing amplifier reduces the transducer output by an amount equal to a compensation signal provided by the microcomputer. Once the output is reduced to a predetermined desired level, the value of the compensation signal is stored in memory for later use during a run mode. In the run mode, the actual supply airflow rate is determined based upon the transducer output less the compensation signal. And the control adjusts the position of the valve until the actual airflow rate meets a desired airflow rate as determined by a room thermostat.

Abstract: An automated heat exchanger tube expander includes an automatically adjustable tool stop, an automatically adjustable back support, and a universal base support. The adjustable stop, the back support, and the base support function together to facilitate the manufacturing of various size tube and fin heat exchangers. The automatic tube expander avoids the time consuming set up for each different size heat exchanger normally required by manual tube expanders.

Abstract: A perforated plastic baffle for a shell-and-tube heat exchanger includes pressure actuated tube seals. Heat exchanger tubes run lengthwise through a cylindrical shell, and baffles traverse the tubes. The pressure actuated seals line each baffle perforation through which the tubes extend. Each seal includes a flexible annular lip that surrounds the tube and extends upstream from the baffle. Fluid flowing through the shell and being redirected by the baffles provides a pressure differential that forces the seals' lips tightly against and around the tubes. In the absence of the fluid pressure differential, the sealing force is greatly reduced which enables the tubes to be easily inserted through the baffle perforations during assembly of the heat exchanger.

Abstract: A liquid/gas bypass line bypasses an expansion device of a refrigeration apparatus. An inlet of the bypass line is connected slightly above the bottom of a condenser so that it can pass either liquid refrigerant or vaporous refrigerant, depending on the level of liquid refrigerant in the condenser. The other end of the bypass line is connected to discharge into the evaporator, bypassing the expansion device. The bypass line functions as a conventional hot gas bypass during low load conditions when the level of liquid refrigerant is below the line's inlet. When the level rises above the inlet, often occurring when the condenser coolant temperature is low and the compressor is fully loaded, the bypass line returns excess accumulated liquid refrigerant to the evaporator. Maintaining the proper levels of liquid refrigerant in both the condenser and the evaporator not only provides the most effective use of their heat transfer surfaces, but also promotes the proper return of oil to the compressor.

Abstract: In refrigeration system, a first solenoid operated valve in parallel disposition with an inlet pressure regulator for refrigerant to a receiver. The refrigeration system also includes a second solenoid operated valve disposed in a receiver bypass line. The first solenoid valve is a normally open valve and the second, bypass solenoid valve is a normally closed valve. A sensor is disposed on the outlet of the condenser of the refrigerant system for determining the condition of refrigerant exiting the condenser. A controller then operates the first solenoid valve and the second solenoid valve to direct flow to the receiver or to bypass the receiver if the refrigerant is subcooled.

Abstract: A premix furnace burner for a gas combusting furnace. The furnace burner includes a premix chamber and a burner plate assembly. The burner plate assembly is comprised of a burner plate with a plurality of relatively small apertures for the passage of a mixture of combustible gas and air and an annular ring for retaining the burner plate. The annular retaining ring determines the capacity of the furnace burner by appropriately sizing of the opening in the annulus of the retaining ring to sealingly overlay a selected portion of the burner plate apertures. The retaining ring further secures the burner plate in the correct operational position while simultaneously permitting the burner plate to expand and contract in response to temperature changes induced by combustion of the gas and air mixture.