Two-Stage Screw Air Compressors

Two-stage compression splits one compression into two stages with intercooling between them, lowering the inlet temperature of the second stage, which helps reduce energy loss in the compression process and lower the discharge temperature. For models with higher power that run continuously over long periods, this structure is more clearly worthwhile. The firstAir brand offers two two-stage models: FPM+-T and FASV+-TMA.

Division of Power Between the Two Series

The FPM+-T covers 55–90 kW with air delivery of 3.76–20.80 m³/min, in models FPM+55A/W-*T, FPM+75A/W-*T and FPM+90A/W-*T; the FASV+-TMA covers 22–355 kW with air delivery of 1.16–73.00 m³/min, extending from FASV+22A*TMA to FASV+132A*TMA. The former serves medium-power continuous air supply, while the latter spans a wider power range and can carry the main air supply duty.

The Relationship Between Pressure and Air Volume

Both models have a working pressure of 0.7–1.25 MPa and offer four pressure steps: 0.7, 0.8, 1.0 and 1.25 MPa. The same model delivers different air volumes at different pressures: taking the FASV+-TMA as an example, the air delivery at 0.7 MPa and at 1.25 MPa differs noticeably, and the higher the pressure set, the smaller the air output. Selection should look up the air delivery at the actual working pressure rather than simply taking the maximum value.

Technical Specifications

Selection Points

1. First determine the working pressure, then match the air delivery at that pressure, avoiding a mistaken selection based on peak values;
2. For medium-power continuous air supply, look first at FPM+-T; for high-power centralized supply, look at FASV+-TMA;
3. The benefit of two-stage compression is related to running hours, so it is worth evaluating for continuous operation;
4. Plan the piping together with the installation space and air outlet size; the connections of both series grow larger with power.