Data centre CDU and rack manifolds — supply, return and cold-plate drops
316L Stainless Steel Tube & Manifold
Bent, welded, electropolished · hydro-tested 16 bar / 3 min · helium leak tested
Cooling circuit
Overview
Custom tube assemblies for the main coolant circuit — the runs that carry deionised water or water-glycol between the stack, the pump, the radiator and the cold plates. Tube is cut, bent and welded to the assembly drawing, electropolished inside, then hydro-tested at 16 bar for three minutes and helium-tested before packing. A fixed geometry holds its bore and cleanliness where a long flexible hose would pick up pressure drop and age in service.
Key features
- 316L wetted parts — tube, forged fittings and flanges; 304 on request
- Bent and welded to drawing — port spacing and bend radius held per assembly
- Electropolished and passivated bore for low-conductivity coolant
- Borescope inspection of every weld and bend before packing
- Hydro-tested at 16 bar for 3 minutes, then helium leak tested
- Ultra-clean flush, dried, ends capped and bagged per assembly
Specification
Technical data
Technical data
| Parameter | Value |
|---|---|
| Wetted material | 316L stainless steel; 304 on request |
| Tube size | Built to drawing — OD, wall thickness and length per assembly |
| Connections | Welded flange, threaded port, weld stub, quick coupling |
| Working pressure | Design to 16 bar |
| Pressure test | Water at 16 bar, held 3 minutes, every assembly |
| Leak test | Helium sniff at joints where specified |
| Wetted surface | Electropolished and passivated |
| Coolant | Deionised water or water-glycol, conductivity ≤ 5 µS/cm |
| Marking | Part number, serial number and date code on the assembly |
| Documentation | Material certificate, weld record and test report per assembly |
Inspection sequence
| Check | Method | What it proves |
|---|---|---|
| Dimensional | Drawing dimensions, port spacing, bend angles | The assembly fits the skid without rework |
| Borescope | Internal view of every weld and bend | No spatter, burn-through or obstruction left in the bore |
| Hydrostatic | Water at 16 bar, held 3 minutes | No weep at the joints and no permanent deformation |
| Helium | Sniff test at the joints | Tightness at the leak rate agreed in the order |
| Cleanliness | Flush and dry; particle check on request | Bore clean enough for cold plates and low-conductivity coolant |
Ordering: send the assembly drawing, or the port layout, bore and overall envelope. State coolant, working pressure, cleanliness level, and whether helium testing and EN 10204 3.1 material certificates are required. Test pressure and leak rate are stated on the report shipped with each assembly.
Application
Where it is used
Stationary fuel cell plant — stack, pump and radiator distribution
Energy storage liquid cooling — PACK-level distribution lines
Related reading
From the engineering notes
Background on the design decisions behind this component — all articles.
Cooling architecture and the insulation question
Why the coolant loop and the electrical barrier must be designed together, and which components keep them apart.
Isolated DC-DC first, then the coolant piping
The 100 Ω/V and 500 Ω/V rules come from touch-safety limits, not from the converter. Worked numbers for a 500 V stack on an 800 V bus, and what they mean for hose length and rigid tube.
316L Stainless Steel Tube & Manifold — product brochure (PDF)
Full specifications, model selection tables and engineering notes. Two pages, English.
Download PDF
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