Relief valve, back-pressure valve and anti-siphonage valve
Before starting the pump, you might forget to open its discharge pipe valve or the discharge pipe may be blocked for some reason. In such a case, a shut-off operation results, thereby damaging the air chamber, pump and pipes. Designed to avoid this kind of trouble, a relief valve opens itself at a preset pressure. Take appropriate actions against the potential rick of frozen liquid.
Notes) Setting position
When returning the chemical to the chemical tank, install the relief valve higher than liquid level of the tank. The discharge outlet of relief valve shall be open atmosphere, because the setting pressure of relief valve may be decreased due to the secondary-side pressure.
Back pressure valve
Too small a differential pressure between the pump’s suction and discharge sides causes a pulsating flow in the piping and then over-feeding phenomenon. A back-pressure valve is intended to prevent this phenomenon. With a back-pressure being applied at the discharge side, the pump’s check ball is kept tight, which stabilizes the discharge rate.
If the pump’s discharge side is lower in pressure than its suction side, the fluid discharges itself. An anti-siphonage valve is provided against such natural discharging.
Outline drawing / model
Valve code explanation
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