Designing a Function-Enhanced Suction Accumulator for Rotary Compressor

Suction accumulator in rotary compressor is an important component from standpoints of compressor cost, performance, sound and ability of controlling excess liquid refrigerant. Because of its importance, it deserves its due attention to enhancement of its functions. This paper first defines functions of an accumulator, lists major design parameters and their common ranges. Then, a couple of major accumulator designs with an enhanced function are introduced. Advantages of the enhanced accumulators are discussed. Test observations for the accumulators are presented to demonstrate the contribution. Lastly, tests designed to evaluate effectiveness of an accumulator are proposed. FUNCTIONS OF A SUCTION ACCJ!MULAIDR Rotary compressor with a conventional suction accumulator attached is shown Fig. I. The primary function of a suction accumulator in rotary compressor is to control excess liquid refrigerant. Suction accumulator also serves as a multi-function component in a rotary compressor, including suction muffiing, filtering of contaminants. A brief discussion for various functions follows: FILTER All accumulators are equipped with filtering screen and this is critical for rotary compressor as suction flow directly enters the compression chamber where tight assembly clearances can cause problems. The screen mesh size determines the maximum size of particles that can pass through the filter. If the mesh is too fine, pressure drop across the filter and plugging of the screen may become an issue. MUFFLER Accumulator acts as a suction acoustic muffler. Degree of contribution can r.;p1ge widely in overall sound level and in specific frequency bands. RESERVOIR FOR LIQUID REFRIGERANT This is the primary function of an accumulator. It separates and collects liquid-phase refrigerant from suction stream. If the liquid is allowed to rush into suction, metallic chattering noise and lubrication difficulties may result. PERFORMANCE An accumulator affects compressor perfonnance as a result of suction gas pulsation, pressure drop inside accumulator and heat transfer between accumulator, and surrounding ambient and compressor shell. An accumulator can cost capacity and/or compressor efficiency.