MACHINE FAMILY
Diaphragm Compressors
Zero-leakage by construction — the gas never touches anything that moves.
A hydraulically driven metal diaphragm stack separates the process gas from the hydraulic oil. There is no shaft seal and no sliding seal on the gas side, making it the reference machine for gases that must not leak, must not be contaminated, or are too dangerous to leak.
The envelope
| Recommended discharge pressure | 1–900 bar(g) |
|---|---|
| Flow window | 1–1,000 Nm³/h |
| Per-stage ratio / stages | 7:1 per stage · at most 4 stages on one crankshaft |
| Oil-free | Available / by design |
| Sealing | Hermetic — metal diaphragm stack with tell-tale leak detection port (no shaft seal) |
| Wetted materials | Stainless steel 316L, Duplex 2205, Hastelloy C-276, Monel 400 (Ni-Cu), PTFE / FFP lining or coating |
| Design standards | No dedicated API standard exists for diaphragm machines — the gas heads are pressure vessels typically built to ASME VIII Div.1 or EN 13445. State the required design code, head material and fatigue life in the RFQ. |
Where it is used
- Hydrogen refuelling and storage, at every grade up to 90 MPa
- High-purity, toxic, flammable or valuable gases
- Specialty-gas filling where contamination is not negotiable
- Small-to-moderate flows at very high pressure
Where it stops
- Clean gas only — droplets or solids in the stream rule the family out
- Above 1,000 bar(g) the duty is bespoke design, not selection
- Above about 1,000 Nm³/h the economics fade and the duty goes to review
Diaphragm machines are in documented Chinese production to 90 MPa, with deliveries into operating hydrogen stations; published international ceilings run to 1,000 bar.
Related reading
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