MACHINE FAMILY
Reciprocating (Piston) Compressors
High pressure at real flow — the process-gas workhorse.
Crank-driven piston in a lubricated or non-lubricated cylinder. Still the answer whenever high pressure meets real flow, and the only domestic route to several-hundred-bar process duty outside diaphragm machines.
The envelope
| Recommended discharge pressure | ≤ 400 bar(g) |
|---|---|
| Flow window | 10–100,000 Nm³/h |
| Per-stage ratio / stages | 3.5:1 per stage · at most 4 stages on one crankshaft |
| Oil-free | Available / by design |
| Sealing | Packing / piston rings on the rod (lubricated) — distance piece with vent/ drain is mandatory for hazardous gas; non-lubricated labyrinth designs eliminate cylinder oil |
| Wetted materials | Carbon steel, Stainless steel 316L, Duplex 2205, 13Cr martensitic stainless, Hastelloy C-276 |
| Design standards | API 618 where specified for petroleum/chemical/gas service; Chinese suppliers commonly hold GB/T 20322 (≡ API 618 MOD) certification |
Where it is used
- Process-gas boosting where pressure and flow are both high
- Large-flow hydrogen duties that outgrow diaphragm machines
- Multi-service and multi-gas installations
- The default when a diaphragm machine is too small and a screw tops out
Where it stops
- The gas has to be fundamentally clean — carry-over and solids are what kill it
- Above 400 bar(g) the documented evidence thins and the duty goes to review
- Discharge temperature, not pressure, is what usually decides the stage count
Chinese evidence for crank-driven process machines reaches 50 MPa; published international envelopes run to 1,000 bar for oil-lubricated designs.
Related reading
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