| 摘要 |
A pressure relief device has a chamber formed in a fixed scroll of a scroll-type machine, such as a scroll compressor. A piston is housed within the chamber releasably sealingly engaging a first passage which exposes the chamber to a discharge port formed in the fixed scroll. A second passage exposes the chamber to a suction plenum. A third passage exposes the chamber to pockets formed by the fixed and orbiting scrolls of the scroll compressor. In certain preferred embodiments, a pressure relief valve having a stem and a head is housed within a cavity formed in the piston. The head is biased by a spring into releasable sealing engagement with an aperture formed in the piston. The pressure relief valve passes fluid to the suction plenum whenever the difference between a discharge pressure and a suction pressure exceeds a predetermined value. The piston passes fluid to the suction plenum whenever the ratio of discharge pressure to suction pressure exceeds a predetermined value.
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