Practical selection examples showing how passage count, pressure, speed, media, mounting, and installation space affect rotary union choice.
These are engineering selection examples, not published customer performance claims. Final model selection must be checked against the actual machine drawing, operating media, duty cycle, temperature, pressure, speed, and installation method.
A rotating cutting or clamping assembly may need several independent fluid paths without twisting external hoses. The correct passage count depends on the machine circuit diagram; oxygen, nitrogen, compressed air, and coolant must not be combined unless the machine design explicitly permits it.
| Selection item | Typical question | Begapunk direction |
|---|---|---|
| Passages | How many independent circuits cross the rotating interface? | Choose the same number of isolated passages, with spare capacity only when justified. |
| Pressure and media | What are normal and peak pressure for each circuit? | Confirm every medium and pressure separately before model approval. |
| Speed | Continuous rotation or intermittent indexing? | Use continuous-duty speed, not only peak RPM. |
| Mounting | Threaded body or flange pattern? | Verify bolt pattern, port orientation, and available envelope in CAD. |
BP-2P-0001 can be evaluated for two low-pressure circuits. Three or more circuits require a matching multi-passage model or a custom review. The machine builder must confirm gas compatibility and applicable safety requirements.
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Salt, humidity, temperature cycling, and difficult maintenance access can change the required housing finish, shaft material, bearing protection, seal compound, and test plan. A standard indoor pneumatic model should not be assumed suitable for offshore service.
| Input required | Why it matters |
|---|---|
| Media and concentration | Determines seal and metal compatibility. |
| Pressure, RPM, and duty cycle | Defines the combined pressure-speed operating point. |
| Temperature range | Affects elastomer selection and dimensional clearances. |
| Corrosion or test standard | Defines coating, material, and validation requirements. |
| Maintenance interval | Influences bearing protection and serviceability. |
BP-2P-130-0001 is a heavy-duty catalog reference, not an automatic offshore solution. Any corrosive or safety-critical application requires drawing review, material confirmation, and an agreed validation plan.
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Even when pressure and RPM are suitable, installation can fail because of bolt-pattern mismatch, insufficient hollow-bore clearance, hose interference, or rigid piping loads. A CAD fit check reduces dimensional risk before production.
| Check | Required confirmation |
|---|---|
| Hollow bore | Clearance around the shaft, drawbar, cable, or tooling. |
| Envelope | Body diameter, total length, and service access. |
| Mounting | Bolt circle, thread specification, depth, and locating feature. |
| Ports and hoses | Fitting size, bend radius, and freedom from external load. |
| Operating point | Media, normal pressure, peak pressure, RPM, and duty cycle. |
BP-2P-30-0001 provides a 30 mm hollow-bore catalog option. Download or request the current drawing and confirm all interfaces in the machine assembly before ordering.
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2-in-2-out flange mount, 1 MPa, 200 RPM. Laser cutting & packaging.
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Heavy-duty 2-in-2-out, 5 MPa, 80 RPM. Base for custom offshore designs.
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2-in-2-out with Ø30 mm hollow bore, 1 MPa, 150 RPM. CNC coolant.
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Request a Free Quote →Technical Note: Case study data reflects actual customer outcomes as of June 11, 2026. Results vary by application, environment, and maintenance practices. Contact our engineering team for a feasibility assessment specific to your machine. Last updated: June 11, 2026.