Bypass Valve
4Pages

APPLICATIONS Bypass valve type GA is intended for use as a pressurerelief valve in hydraulic systems, oil circulation circuits, oil firing systems, etc. The valve is intended for mineral oils and liquids with similar properties and must not be used for water, steam, corrosive liquids or the like. MODE OF FUNCTION Bypass valve type GA is direct-acting and is distinguished by its high speed during the opening process, enabling pressure surges in the event of sudden changes in volumetric flow to be kept at a low level. The valve features a built-in, automatically acting hydraulic pressure compensation device which endeavours to keep the pressure rise as small as possible within the flow rate range area specified for the valve (cf. pressure rise in response to increasing flow for a purely spring-loaded valve) During the closing process, the pressure largely coincides with the pressure during the opening process. For fine adjustment of the valve characteristics, the valve is provided with a throttling screw at the outlet which, upon delivery, is factory set and which does not usually require subsequent adjustment. VERSIONS The bypass valve type GA is available in the following versions: GAR with valve casing for threaded pipe connections GAS with valve casing for SAE-flanged pipe connections GAD with valve casing for DIN-flanged pipe connection Model Code Valve series M o d e l R = Threaded pipe connections S = SAE-flanged pipe connections D = DIN-flanged pipe connections Size (size code according to type specification overleaf) Design specification (upon deviation from standard design - 0 indicates standard design) Design modification (1 - indicates original design) Valve spring (code according to type specification overleaf) or Special variant (max. opening pressure determined by the variant) Example: GAS 04001 T040, valve with SAE-flanged connections dia. 40 mm in standard design with spring for max. 4.0 MPa opening pressure. G GA 1102 GB A MATERIAL Valve casing - steel for types GAR and GAS - nodular iron for type GAD Spring casing - steel for sizes 012, 015, 020, 034 - nodular iron for sizes 025, 040, 065, 100, 112 O-rings - Viton rubber Other parts - steel Bypass Valve GA Type Max pressure: 10 MPa Max flowrate: 15 dm3/s (900 I/min) GA 1102.02 GB

www.imo.se GA 1102.02 GB 2 INSTALLATION A bypass valve is to be installed in the outlet line as close as possible to the unit which is to be protected against excessively high pressure by the valve. No components liable to block the flow and prevent the valve from releasing liquid when the opening pressure has been attained may be installed in the return line from the valve. Overflowing liquid should be returned to tank enabling the heat evolved in overflowing to be distributed among the largest possible liquid volume. Bypass valve type GA may be mounted in any position. In order for the...

www.imo.se GA 1102.02 GB 4 SELECTION DIAGRAM The curves show approximations of the valve characteristics set upon delivery at maximum nominally adjustable opening pressure with valve springs T008, T040, T075 and T100 respectively. The pressure rise (accumulation) will not be more than 10% above the set pressure but will have a minimum value of 0.2 MPa. www.imo.se