Zero Velocity Valve
Zero Velocity Valves are developed to eliminate water hammer problems. In common practices Pumps and Swing Check Valves are installed on the pump discharge end. Theoretically, the swing check valve closes quickly when the pump is shut off, but actually not quick enough to prevent reversal of flow. The wedge will slam against its seat and will cause noise, vibration and pipe stressing. All these hindrance can be controlled by use of Spring Loaded Zero Velocity Valve.
Water Hammer is a phenomenon that is caused when fluid flowing in a system through a pipe is stopped or flow suddenly interrupted causing high pressure shock waves. It is a severe problem on pump discharge when swing check and other conventional check valves are used. These types of valves have very slow closing characteristics and with high head causes shock waves causing problems such as : pipe deflection and rupture, pump damage etc.
The Shiva Durga Zero Velocity Valve is a spring-assisted, enter-guided, flanged check valve that provides reliable, low maintenance service for a wide range of luid and pressure / temperature combinations. The valve consists of a body, seat, spring, and disc with stem and guide bushing. Check valves are avaialable in a variety of sizes and pressure rating and in variety of metals to meet most check valve requirements.