A ROTAN pump-mounted bypass valve protects the pump and motor from brief excess pressure by recirculating liquid within the pump. It does not protect the entire pipe system and should not be used for continuous pressure control. The pump and the connected system need separate protection decisions based on the actual duty.
What does each protection device do?
| Device | Main role | Important limit |
|---|---|---|
| Pump-mounted bypass valve | Relieves short pressure peaks at the pump. | It is not a pipeline safety valve; prolonged recirculation heats the liquid and pump. |
| Separate line relief or equivalent protection | Protects the discharge piping and connected equipment according to the system design. | Its capacity and return path must be engineered for the credible blocked-outlet case. |
When should you specify a bypass valve?
A positive-displacement gear pump can raise pressure rapidly against a closed discharge. ROTAN pumps may be supplied with or without the pump-mounted valve. If the valve is omitted, specify equivalent protection for the pump and motor. Separately assess how the piping is protected. Confirm these points before start-up:
- Identify possible blocked outlets and the full-flow relief path.
- Check the selected flow direction. If a ROTAN bypass valve is fitted, its spring side must face the suction side; reversing motor rotation changes suction and discharge.
- Confirm the valve option, setting and operating limits against the exact pump manual and approved system design. Never use the valve as a routine throttling control.
What should an RFQ include?
Send enough information to confirm the correct pump and valve arrangement:
- Complete ROTAN series, size and configuration or existing nameplate.
- Liquid, viscosity at operating and start-up temperatures, and temperature range.
- Required flow, normal and maximum differential pressure, and motor or speed details.
- Flow direction, piping sketch, blocked-outlet scenario, relief return destination and required valve option.
Frequently asked questions
Can the integral bypass replace a pipe-system safety valve?
No. DESMI distinguishes pump protection from protection of the whole pipe system.
Can the pump run continuously across its bypass?
No. Long recirculation can heat the pump and liquid. Use an appropriate control method for continuous duty.
Does reversible rotation make valve orientation automatic?
No. Recheck suction and discharge after changing direction, and orient the fitted valve accordingly.
Review the configuration
Compare ROTAN families in the existing selection guide, browse DFIN pump products, then send the duty and protection details for a quotation.