Suction Line Accumulators

A suction line accumulator sits between the evaporator and the compressor to catch liquid refrigerant that would otherwise reach the compressor. Liquid slugs damage valves, dilute the oil and cause the pressure spikes that crack discharge pipework - and the risk is highest exactly when the system is working hardest: at start-up after defrost, after a hot gas cycle, or on a system whose expansion valve is oversized.

Eighteen sizes run from SLA-204 to SLA-2117, with ODF connections from 1/2 inch to 2-1/8 inch and volumes from 1.5 L to 11.0 L. Shell diameters run from 102 mm to 219 mm. Capacity is published at -18 C for R22 (3.2 to 45.0 kW) and R404A (2.8 to 64.0 kW), which is the range that covers most cold store and blast freezer duties.

The internal arrangement matters more than the volume: gas enters at the top, changes direction, and liquid falls out of the stream while oil is metered back through a small bleed hole at the bottom. That bleed hole is sized to return oil at the expected mass flow - too large and liquid passes through with the oil, too small and oil accumulates in the accumulator.

Three body configurations (FIG1, FIG2, FIG5) differ in connection layout to suit different pipe runs.

Install vertically, as close to the compressor as practical, and insulate it: an uninsulated accumulator condenses moisture and, more importantly, picks up heat that flashes the liquid it is holding. Size by the maximum liquid slug the system can produce, not by average flow.