Type AB Pressure Reducing Valve

The AB pressure reducing valves are balanced inlet design, which are suitable for use on compressed air, gas, water and oil. These valves are used in a variety of applications throughout industry, where their outstanding accuracy and reliability have been proven. The AB is also a WRAS - Approved Product. Valves are supplied in sizes half inch to two inch in S. G. Iron with ends screwed female to customers requirements. Inlet pressures of up to 27.60 Barg for air and liquid service can be accommodated. (Consult Broady Technical Sales Engineers for further information). Reduced pressure ranges of 0.70 to 8.30 Barg are possible.

All valves are supplied with a nitrile disc and diaphragm for air, gases, oils, etc. as standard, but other materials are available on request. Valves for potable water service are supplied with a neoprene disc and diaphragm.

High pressure is admitted to the underside of disc valve. The spring is then compressed the requisite amount and the valve opened permitting pressure to pass to the service side. Expansion and consequent reduction of pressure takes place as it leaves the valve orifice and the reduced pressure is then controlled by the reaction of the spring to the reduced pressure acting upon the area of the piston. If the reduced pressure tends to fall, the spring, through the medium of the diaphragm, opens the valve and increases the orifice area. Conversely, if the pressure rises the valve closes until the required downstream pressure is restored; uniformity of the reduced pressure is thereby maintained
within very close limits. The reduced pressure can be varied to requirements by compressing or relaxing the spring. The adjusting screw is provided for this purpose. Compressing the spring increases the reduced pressure, relaxing the spring decreases the reduced pressure.

All valves should be fitted in a horizontal pipeline with, flow in the direction of the arrow cast on the side of the body. The adjusting screw should be directly above or below the pipeline. The pipe must be clean and free from dirt, scale, etc. It is advisable to fit a stop valve on the high pressure side of the line. A relief valve should always be fitted where dead end conditions apply.

Type_AB.pdf