The Back Pressure Maintaining Valve is designed to ensure the system does not go below a set pressure on the inlet side.
Different ways of maintaining a back-pressure
Spring loaded – For general duties and orifice sizes up to 5.8mm (0.220″) a simple spring loaded seat design is used covering pressure up to 544 bar (8000 psi).
Dome Loaded – Pressursised gas is stored in a dome on one side of a diaphragm of piston to balance upstream fluid pressure in the other side. For maintaining large flows at medium and high pressures, spring sizes become too large and the high spring forces difficult to contain. A more compact and convenient solution is to use a dome laoded valve. In the case of pneumatic systems, the dome gas is obtained by bleeding a small flow from the supply side of the system until the desired pressure is obtained. For hydraulic systems where a separate gas pressure supply (e.g. gas bottle) is required for the initial charging of the dome – an externally loaded BPMV is suitable, please call our technical department for further details.