Dual volume-ratio scroll machine

Abstract

The present invention provides the art with a scroll machine which has a plurality of built-in volume ratios along with their respective design pressure ratios. The incorporation of more than one built-in volume ratio allows a single compressor to be optimized for more than one operating condition. The operating envelope for the compressor will determine which of the various built-in volume ratios is going to be selected. Each volume ratio includes a discharge passage extending between one of the pockets of the scroll machine and the discharge chamber. All but the highest volume ration utilize a valve controlling the flow through the discharge passage.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. patent application Ser. No. 10 / 726,713 filed Dec. 3, 2003 which is a continuation of U.S. patent application Ser. No. 10 / 195,280 filed Jul. 15, 2002 which is a continuation-in-part of U.S. patent application Ser. No. 09 / 688,549 filed on Oct. 16, 2000. The disclosure of the above application is incorporated herein by reference.FIELD OF THE INVENTION [0002] The present invention relates to generally to scroll machines. More particularly, the present invention relates to a dual volume ratio scroll machine, having a multi-function seal system which utilizes flip or flip seals. BACKGROUND AND SUMMARY OF THE INVENTION [0003] A class of machines exists in the art generally known as scroll machines which are used for the displacement of various types of fluids. Those scroll machines can be configured as an expander, a displacement engine, a pump, a compressor, etc., and the features of the present inve...

AI Technical Summary

Benefits of technology

[0004] Scroll-type apparatus have been recognized as having distinct advantages. For example, scroll machines have high isentropic and volumetric efficiency, and hence are small and lightweight for a given capacity. They are quieter and more vibration free than many compressors because they do not use large reciprocating parts (e.g. pistons, connecting rods, etc.). All fluid flow is in one direction with simultaneous compression in plural opposed pockets which results in less pressure-created vibrations. Such machines also tend to have high reliability and durability because of the relatively few moving parts utilized, the relatively low velocity of movement between the scrolls, and an inherent forgiveness to fluid contamination.

[0008] To maximize efficiency, it is important for the wrap tips of each scroll member to sealingly engage the end plate of the other scroll so that there is minimum leakage therebetween. One way this has been accomplished, other than using tip seals (which are very difficult to assembly and which often present reliability problems) is by using fluid under pressure to axially bias one of the scroll members against the other scroll member. This of course, requires seals in order to isolate the biasing fluid at the desired pressure. Accordingly, there is a continuing need in the field of scroll machines for axial biasing techniques—including improved seals to facilitate the axial biasing.

[0011] Scroll compressor design specifications for air conditioning applications typically include a requirement that the motor which drives the scroll members must be able to withstand a reduced supply voltage without overheating. While operating at this reduced supply voltage, the compressor must operate at a high-load operating condition. When the motor is sized to meet the reduced supply voltage requirement, the design changes to the motor will generally conflict with the desire to maximize the motor efficiency at the primary compressor rating point. Typically, the increasing of motor output torque will improve the low voltage operation of the motor but this will also reduce the compressor efficiency at the primary rating point. Conversely, any reduction that can be made in the design motor torque while still being able to pass the low-voltage specification allows the selection of a motor which will operate at a higher efficiency at the compressor primary rating point.

[0012] Another aspect of the present invention improves the operating efficiency of the scroll compressor through the existence of a plurality of built-in volume ratios and their corresponding design pressure ratios. For exemplary purposes, the present invention is described in a compressor having two built-in volume ratios and two corresponding design pressure ratios. It is to be understood that additional built-in volume ratios and corresponding design pressure ratios could be incorporated into the compressor if desired.

Problems solved by technology

For example, scroll machines have high isentropic and volumetric efficiency, and hence are small and lightweight for a given capacity.

One way this has been accomplished, other than using tip seals (which are very difficult to assembly and which often present reliability problems) is by using fluid under pressure to axially bias one of the scroll members against the other scroll member.

When the motor is sized to meet the reduced supply voltage requirement, the design changes to the motor will generally conflict with the desire to maximize the motor efficiency at the primary compressor rating point.

Typically, the increasing of motor output torque will improve the low voltage operation of the motor but this will also reduce the compressor efficiency at the primary rating point.

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