Scroll type fluid machine having a circulation path and inlet path for guiding refrigerant from a discharge chamber to a drive casing and to a rear-side of movable scroll

摘要

In a scroll-type fluid machine (4), a refrigerant in a discharge chamber (80) is adjusted at prescribed discharge pressure by using a discharge valve (84), discharged from a scroll unit (52), and supplied to a refrigeration circuit (2), and the machine has a circulation path (7) for introducing the refrigerant in the discharge chamber from the refrigeration circuit toward a drive casing (22) while maintaining the refrigerant pressure, and an inlet path (93) formed in a compression casing (24) and leads the refrigerant in the circulation path to the rear side of a movable scroll (54) to make the led refrigerant counteract the refrigerant discharge pressure acting on the front side of the movable scroll.