Abstract: A self-modulating scroll compressor includes a built-in volume ratio that is defined as the ratio of a volume of a compression pocket just after completion of suction, i.e. at a beginning of a compression cycle, to the volume of the compression pocket just prior to discharge, i.e. at the end of the compression cycle. The built-in volume ratio can be controlled by the geometry of the scrolls and can be modified by, for example, extending the wrap or adding more turns to the wrap. Because the built-in volume ratio decreases to an effective volume ratio at lower capacity operation, the built-in volume ratio is at least 2.4 in order to optimize overall compressor efficiency.

Abstract: A scroll compressor has a reed valve mounted on a central discharge port. The reed valve has a valve portion at a first end and a pin holding the reed valve onto a non-orbiting scroll member at a second end. The reed valve extends along a plane which is non-perpendicular to a drive axis of a drive shaft such that the second end, which receives the pin, is further removed from the compression chambers than is the first end of the reed valve, which covers the central discharge port.

Abstract: Compressors are defined by two relatively moving members, which have a relative orbital movement between the two. Piezoelectric elements are associated with each of the two moving members to cause the moving members to result in the orbital movement.

Abstract: A compressor is provided with a dimple and a lower end cap to receive a positioning fixture pin to position the lower end cap prior to a welding operation. The use of the dimple ensures the lower end cap is properly positioned when welding occurs. In the past, lower end caps have often been mis-aligned when welded to the center shell. Further, the dimple provides the dual function of positioning a magnet within the compressor housing.

Abstract: A scroll compressor is provided with a multiple-speed motor. A control selects a speed for operating the motor, along with selecting between several available options for the system capacity adjustment to meet external load demands in a most efficient and reliable manner. The disclosed embodiment includes an economizer circuit, an unloader function, and an optional suction modulation valve. By utilizing each of these features in combination with the multi-speed motor for the compressor, the present invention is better able to tailor provided capacity to desired capacity.

Abstract: A scroll compressor has a device which may be actuated to limit the orbit radius of the orbiting scroll. The device is moveable between an unactuated position at which it is spaced from a hub for the scroll compressor, and an actuated position at which it limits the orbit radius of the hub. The device may be actuated when reduced capacity is desired.

Abstract: A scroll compressor is provided with a passage for providing both an unloader function and an economizer injection function. This common passage communicates with separate ports. The ports that are exclusively used for by-pass unloading operation are open only during by-pass unloading operation, but blocked off by a check valve during vapor injection operation. The other, normally smaller vapor injection ports are open for both vapor injection and by-pass unloading operation. By utilizing these two sets of ports, a smaller total port area is provided for vapor injection operation and a much larger total open port area for by-pass operation. The different open port areas for by-pass unloading operation and vapor injection operation allows optimization of compressor operation at both of those regimes of operation.

Abstract: A scroll compressor is provided with a cavity in its back pressure chamber to increase a volume of the back pressure chamber. In this manner, at start-up, the back pressure chamber will not be effective to bias the two scroll members together until this enlarged volume is filled with a compressed refrigerant. This reduces the load on the electric motor at start-up.

Abstract: A scroll compressor is provided with an oil bleed valve that selectively communicates a discharge pressure chamber to a suction pressure chamber. The oil bleed valve controls flow of hot oil through a passage and onto a safety shutoff switch for an electric motor.

Abstract: A scroll compressor is provided with an orifice plug inserted into an oil passage. The plug has an opening which is positioned to restrict the flow of oil through the passage, and in particular at higher speeds. The opening is formed at an outer periphery of the plug, and may be positioned at a location spaced furthest from the center of rotation of the shaft.

Abstract: The drive connection between an eccentric pin and a slider block in a scroll compressor is angled such that any vertical force between the two will drive the slider block away from the orbiting scroll member. In this manner, manufacturing tolerances will not result in any drive connection which can have a net vertical force driving the slider block toward the orbiting scroll member.

Abstract: A scroll compressor includes a scroll member having a base and a generally spiral wrap that extends from the base to define a portion of a compression chamber. The scroll member is made of a cast iron material comprising a microstructure having graphite nodules.

Abstract: A scroll compressor has lubricant flow which communicates lubricant onto a motor protector when adverse conditions are present causing the motor protector to trip the motor and stop further rotation. The lubricant is returned to an oil sump through a normal return path. The normal return path outlet may be positioned above the motor protector such that lubricant will contact the motor protector when adverse conditions are present, or the outlet may be remote from the protector. When the outlet is remote from the protector, a funnel and tubing divert the oil to the motor protector under adverse conditions. Alternatively, a passage communicating with the normal return path is selectively blocked when an adverse condition is present. At that time, lubricant is forced into an alternative oil path, which is positioned above the motor protector.

Abstract: A scroll compressor is provided with spaced grooves in a base of one of the two scroll members. A recess is formed in a wrap tip of the other scroll member. The recess in the wrap tip bridges a space between the grooves of the other scroll member. This bridging equalizes pressure between two parallel intermediate compression chambers. Pressure equalization between the chambers improves compressor efficiency.

Abstract: Oil retention recesses are formed on either or both orbiting and non-orbiting scroll elements. In one embodiment, the recesses are formed in a tip of a wrap of at least one of the scroll members. In another embodiment the recesses are formed on the base of at least one of the scroll elements. The recesses ensure that a sufficient quantity of oil is captured within the recesses to provide the lubrication into the interfacing surface of these elements. The recesses help, after a compressor is shutdown for long periods, to provide as lack of lubricant between the engaged scroll elements upon compressor start up. Other events may also cause momentary loss of oil supply at the compressor, such as, for example, compressor flooding. The recesses also help during intermittent interruption of oil delivery or when the amount of oil circulation is less than desirable.

Abstract: A thermostat for sensing an unduly high temperature in a sealed compressor, which is a scroll compressor in the disclosed embodiment, extends through the housing of the sealed compressor into the body of a non-orbiting scroll. Since the thermostat extends through the housing, the wires need not be sealed as they extend from the housing. Still, the thermostat is positioned close to the compression chambers and at a location that will quickly heat when undesirable conditions exist within the sealed compressor. In this manner, the present invention is able to rapidly respond to an undesirable situation to allow a system control to have an indication of the undesired condition.

Abstract: A scroll compressor has a stop on its eccentric pin to selectively engage a notch in a slider block, and prevent the slider block from moving upwardly and contacting a rear surface of the orbiting scroll. The present invention prevents this unwanted contact, and the resultant wear.

Abstract: A scroll compressor assembly includes a shaft having an eccentric pin that orbits a first scroll member relative to a second scroll member. The eccentric pin has a length extending from a base end to a distal end, which defines a contact area having a slight crown that engages a slider block. The contact area is moved toward the distal end of the eccentric pin to improve the stability of at least one of the first and second scroll members.

Abstract: A slider block for a scroll compressor has a recess formed in a wall between a flat portion on the outer surface and a chamfer formed on the inner surface. The recess eliminates a high stress area of the prior art, and reduces cracks originating from this area of the slider block.

Abstract: A vent is included into a scroll compressor for protecting a refrigerant system in the event of loss of charge. The vent selectively taps an entrapped compression chamber to a housing chamber which surrounds the motor. In the event of a low charge, the gas in the compression chamber will be at a high temperature, and will heat the motor when the vent opens. The vented heated gas will then actuate a temperature protection device on the motor, causing the motor to stop rotation. In further embodiments, the compression chamber which supplies the tapped fluid is the discharge port.