IMO Circor type GA Bypass valves GAR, GAS and GAD.
IMO ab offers a special single acting bypass valve for use in hydraulic systems where a safe and accurate opening pressure is required. The GA valve has a built-in automatic hydraulically acting pressure compensator, which ensures very low pressure rises and pressure variations in the event of opening. This applies both to opening and to the damped closing process. The valve is thus designed not to create undesirable pressure surges or pressure variations during opening and/or closing.
Version: IMO GAR, GAS and GAD.
Application:
IMO GA valves are intended for use in oil-based systems as a safety valve or bypass valve i.e. the valve can be used as a working valve*. The valve is adjusted to the opening pressure by means of the spring tension and damped by means of the Trottle screw. During flow-through operation the valve is thus in hydraulic balance.
*It is however a condition that the bypass valve is not exposed to pulsating flow if it is to function as a working valve. Pulsating flow can be dampened by means of pulsation dampeners.
Installation:
According to Manual page 2 however close location to pressure transmitter (pump), as well as oil-filled pipe is recommended for safe performance. Water or chemicals are not compatible with GA valves. Water should therefore not be used as a test medium.
Since a large amount of energy is released into the liquid through the valve, it is not recommended to make a bypass to the suction side of the pump, but instead return to the tank.
Please refer to technical brochure GA 1102 GB for free download.