The RAF 88 are adjusted to eliminate hazardous pressure surges typical of water hammer conditions. A water hammer is caused by an abrupt shutoff of a pump or rapid closure of a main valve, causing a fast, propagation of low-pressure fornt, followed by an extremely high-pressure waves, each one composed of alternating low and high pressure is created within a few seconds.
The RAF 88 is a piloted hydraulic valve activated by line pressure. The valve has two pilots, for high and low pressure. Under normal conditions, the RAF 88 is closed. It opens when the line pressure drops below a preset pressure, in anticipation to the following surge, and remains open until the fluctuations subside.
Use RAF 88 to protect water lines against water hammer damages. Uphill supply lines of considerable length and large diameter pipes are more susceptible to water hammer damages.
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