Abstract: An improved control over the pressure vented or tapped to a back pressure chamber in a scroll compressor is achieved by maintaining a vent hole closed for the majority of the operational cycle of the scroll compressor. The hole is preferably selectively exposed to a discharge pressure for a small portion of the cycle, and to an intermediate pressure for a second small portion of the cycle. Other than those two small portions, the hole is preferably closed. The invention reduces pulsation in the back pressure chamber and also reduces pumping losses caused by fluid moving into and out of the back pressure chamber through the hole. In one embodiment, grooves are formed in the fixed scroll member to communicate a selected intermediate pressure and a discharge pressure to locations on the base plate of the fixed scroll member. A vent hole in the wrap of the orbiting scroll member cyclically moves over the two grooves.

Abstract: A screw machine (10) has a rotor housing (12) defining overlapping bores (12-1, 12-2). Female rotor (14) is located in bore (12-1) and male rotor (16) is located in bore (12-2). A wear resistant coating is deposited on the tips (14-1, 16-1) of the rotors. A conformable coating is deposited on the valleys (14-2, 16-2) of the rotors. A conformable coating is depsoited on the surface of the bores coacting with the rotors.

Abstract: A low cost protective clutch member is positioned adjacent an end of the drive shaft in a scroll compressor. The device is a thin washer having a tab which is selectively driven against the housing stop when the compressor is driven in a forward direction, but is movable into a notch in the shaft when the shaft is driven in a reverse direction. The tab prevents rotation of the shaft when in the notch.

Abstract: A variable size is provided for a discharge port in a scroll compressor. The variable size is movable dependent on conditions within the scroll compressor to achieve a desired pressure ratio based upon operational conditions in the compressor or an associated refrigerant cycle. In one embodiment a plunger moves axially to increase or decrease the size of a discharge port. In a second embodiment, the plunger rotates about an axis and has a groove that is selectively aligned with the port to increase or decrease the effective size of the port.

Abstract: A compressor diagnostic system incorporates a control which receives a plurality of data streams about various operational features of the compressor. As an example, both temperature and pressure of the suction and discharge refrigerant are taken and sent to the control. Moreover, information with regard to the power being supplied to the motor is taken and stored. All of this information is utilized at a control which compares the information to expected values and determines a fault based upon the evaluation. Moreover, in another feature of this invention, much of this data is stored, and maintained at the compressor. In the event of a compressor failure, this stored information will provide a maintenance worker with a good indication of why the compressor failed.

Abstract: A pressure responsive oil flow regulating supply valve assembly includes an oil supply input; an oil supply output; an oil flow path defined between the input and output. A valving mechanism located in the oil flow path includes a device for restricting oil flow at a first level in response to normal pressure and for restricting oil flow at a second level in response to high pressure conditions. In addition, other levels of restriction may be provided for other pressure conditions.

Abstract: A system includes a motor mounted within a housing and a compressor pump unit. A single-phase PSC motor includes a switch assembly which selectively connects primary or alternate windings. During normal load operation, when maximum efficiency is desired, the switch is placed in one position, then during high load operation, when maximum torque output is needed at maximum a load point, the switch is placed in the closed position. In effect, the number of main winding turns is decreased and the motor is strengthened. As the auxiliary capacitors are also now connected in parallel, the net effect is an increase in the total auxiliary capacitance, which also serves to strengthen the motor. Another embodiment provides a switch for a three-phase WYE connected motor. In yet another embodiment, a three phase delta connected motor switch is provided.

Abstract: An unloader valve for a scroll compressor to selectively communicate suction and discharge is positioned outwardly of the compressor housing. In this way, the unloader valve is ideally positioned to address several system failures. As an example, loss or charge, reverse running, fan failure, etc. are all addressed in an efficient and quick manner. The unloader valve may be the normal unloader valve controlled by a system control which also selectively controls capacity. The unloader valve control is modified such that it is also operable to open the unloader valve when a system failure is detected.

Abstract: An improved scroll compressor having an axially movable non-orbiting scroll eliminates the need for a separator plate. With the elimination of the separator plate, a back pressure chamber is provided to resist the discharge pressure which will be directed against a rear face of the non-orbiting scroll. In other embodiments, a seal on the rear of the non-orbiting scroll contacts the inner periphery of the end cap. Various ways of increasing the discharge pressure volume, or eliminating undesirable noise are also disclosed. Further, several ways of connecting the end cap to the center shell are also disclosed.

Abstract: A scroll compressor is provided that has greater control over the compressed volume by having a plurality of sequentially spaced unloader valves and associated holes. By providing the plurality of valves, a control achieves greater variation over the final compressed volume. The present invention is most preferably utilized in the type of scroll compressor having a hybrid wrap geometry to provide an increased volume of refrigerant adjacent the suction area of the compressor.

Abstract: A pressure responsive oil flow regulating supply valve assembly includes an oil supply input; an oil supply output; an oil flow path defined between the input and output. A valving mechanism located in the oil flow path includes a device for restricting oil flow at a first level in response to normal pressure and for restricting oil flow at a second level in response to high pressure conditions. In addition, other levels of restriction may be provided for other pressure conditions.

Abstract: A compressor diagnostic system incorporates a control which receives a plurality of data streams about various operational features of the compressor. As an example, both temperature and pressure of the suction and discharge refrigerant are taken and sent to the control. Moreover, information with regard to the power being supplied to the motor is taken and stored. All of this information is utilized at a control which compares the information to expected values and determines a fault based upon the evaluation. Moreover, in another feature of this invention, much of this data is stored, and maintained at the compressor. In the event of a compressor failure, this stored information will provide a maintenance worker with a good indication of why the compressor failed.

Abstract: A refrigerant cycle is provided with an expansion device that is movable between a normal mode of operation and a low charge mode of operation. In the low charge mode of operation, the expansion device does not lower the pressure of the refrigerant as much as it does in its normal mode of operation. In this way, the relatively high pressure ratios that are experienced by a compressor during a low charge operation will not be experienced. Instead, the pressure ratio across the compressor is reduced during low charge operation, and the compressor will be better protected.

Abstract: A scroll compressor is provided with a clutch to minimize or eliminate the detrimental effects of reverse rotation. Generally, the clutch prevents rotation of the shaft during both powered and unpowered reverse rotation. The clutch could be subject to damage during powered reverse rotation, and thus a clutch protection mechanism is incorporated that will prevent the clutch from moving to an actuated position if powered reverse rotation occurs.

Abstract: A low cost protective clutch member is positioned adjacent an end of the drive shaft in a scroll compressor. The device is a thin washer having a tab which is selectively driven against the housing stop when the compressor is driven in a forward direction, but is movable into a notch in the shaft when the shaft is driven in a reverse direction. The tab prevents rotation of the shaft when in the notch.

Abstract: A scroll compressor is provided with a clutch to minimize or eliminate the detrimental effects of reverse rotation. Generally, the clutch prevents rotation of the shaft during both powered and unpowered reverse rotation. The clutch could be subject to damage during powered reverse rotation, and thus a clutch protection mechanism is incorporated that will prevent the clutch from moving to an actuated position if powered reverse rotation occurs.

Abstract: A number of improvements increase the flow of lubricant within a scroll compressor. A centrifugal oil separator is mounted on the discharge port to remove oil from the refrigerant. The oil is returned through a leak path such that the oil can easily return back to a suction pressure chamber. The leak path is preferably upstream of a check valve. Thus, at shutdown, the leak path will not allow upstream components to also equalize in pressure with the suction pressure chamber of the compressor. Further, a number of embodiments include ways of resisting flow of refrigerant through the leak path, while still allowing oil flow. A number of valve elements are described which perform this function. Alternatively, labyrinth flow paths, or positioning of the return paths such that it will be closed when the compressor is shut down are disclosed.

Abstract: A scroll compressor assembly includes a first linear drive for driving a first scroll along a first linear axis and a second linear drive for driving the first or second scroll along a second linear axis which is non-parallel to the first linear axis. Relative orbital movement between the first and second scrolls is obtained by controlling the frequency of oscillations of the first linear motor along a first linear axis and the second linear motor along the second linear axis. Further, capacity control is achieved by varying the movement of the first and second linear motors.

Abstract: Oil retention recesses are formed in an outer periphery of the slider block of a scroll compressor. The recesses insure that a quantity of oil is captured and maintained during operation and after shutdown of the scroll compressor. If the scroll compressor is operated or started back up during a “starved” lubricant condition, the captured oil insures the scroll compressor can operate without damage for a period of time such that lubricant can be returned to the sealed compressor.

Abstract: A simplified drive arrangement is provided to allow a scroll compressor to be operated at two capacity levels by a reversible electric motor. A pair of one-way clutches are positioned on a pair of parallel shafts. When the motor is driven in a forward direction drive passes through one of the one-way clutches and directly to the orbiting scroll. However, when the motor is driven in a reverse direction, drive passes through a countershaft, which in turn passes through a second one-way clutch. The drive passing through the second one-way clutch will result in the orbiting scroll being driven at a distinct speed then when the motor is driven in a reverse direction. In this way, capacity modulation is achieved with a very simple mechanism.