Their pilot control system is designed to allow the main valve to begin to open during the initial low pressure wave that accompanies power failure of a pump or similiar failure mode. Usually, the anticipation function of the valve is done using a regular low tech timer that opens the valve a pre determined period of time after pump shut down.īobPE RE: Water Main Surge Relief Valve epbpe (Civil/Environmental) 3 Mar 03 19:51īobPE The surge anticipator valve I refer to is the pilot controlled over hydraulically main style as made by Cla-Val, OCV, Ross, etc. If you want to control the negative or low pressure wave, a surge tank design will have to be placed into service. These valves do nothing for this low pressure wave. Prior to arrival of the high pressre positive wave, the valves open to waste water and reference the high pressure wave to atmosphere. A transient starts with the low pressure wave upon pump shutoff at which time the vlves are closed as not to let air into the system which could magnify the problems. I am a little confused though from you posts, these valves work by the anticipation of a surge which is the high pressure wave arrival at the pump station. The valves are quite complicated as you indicate, however, they are not used too frequently if the system works right!!! The valves must be looked at and cycled to make sure they are operational, but they usually dont need much replacement maintenance and are very reliable. RE: Water Main Surge Relief Valve BobPE (Civil/Environmental) 3 Mar 03 16:18 Make sure that your system has adequate supply and pressure to reclose the valve after the initial low pressure wave, otherwise the valve might remain open and never close because the pressure cannot recover enough to reset the pilot system. As I mentioned in my previous post, a surge valve in the wrong application is often worse than using no valve at all. Adjustment is much simpler to initially perform and maintain than a surge valve. A pressure relief valve, on the other hand, will generally only have a high pressure pilot, speed controls, and control pilot for pilot control over the main valve. The initial adjustment and maintenance of the adjustment is critical for proper response and operation of the valve. A surge anticipator valve normally will include: 1- high pressure pilot, 1- low pressure pilot, 1- flow limiter (to restrict amount of main valve opening), 1- control pilot valve, 1- strainer/needle valve assy., opening and closing speed controls, and numerous other cocks, copper tubing, and fittings. The surge anticipator valves (surge relief) are indeed high maintenance valves due to the multiple pilots and complex piping.
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