Breather Valve

Breather Valve

Closed vessels or tanks filled with liquids must have an opening through which the accumulated pressure can be released and vacuum in the tank or vessel compensated. For that purpose MR’s Overpressure and Vacuum Relief Valves are provided with weight-loaded or spring-loaded valve discs. In the case of overpressure in the tank, the overpressure valve disc guided in the housing is lifted and releases the volume flow into the atmosphere. When there is a vacuum in the tank, the overpressure of the atmosphere lifts the vacuum disc and the tank is vented.
EN 13463-1 / EN 13463-5 / API 2000


MR’s Breather Valves are ideal for routine service for vent-to-atmosphere applications.
This valve provides protection against positive or vacuum overpressure, and prevents air intake and evaporative losses of product while helping to contain odorous and potentially explosive vapors.


  • Minimzation of product lossed
  • Replaceable seat
  • Reduction of emissions
  • Excellent flow characteristics
  • Maintenance of pressure up to just below the maximum permissible (tank) pressure


Size From 1 1/2″ (ND 40A)  To 12″ (ND 300A)
Pressure Range From 22 mmH20  To 10000 mmH20
Vacuum Range From 22 mmH20  To 8400 mmH20


No. Description Spec.1 Spec.2 Spec.3
1 Body A216-WCB A351-CF8M B26-319
2 Cover A283-C A351-CF8M B26-319
3 Disc A240-304 A240-316 A240-304
5 Seat A351-CF8 A351-CF8 A351-CF8

– Special materials can available upon request.