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Stop valve The Type 14270 Stop Valve is designed to operate in systems where pressure may be present upstream and downstream of the valve. The operating spool is hydraulically balanced to render the valve insensitive to changing operating conditions, and prevents system pressure from either opening or closing the valve. Air or hydraulic pressure is applied to the operating cylinder to open the valve; closure is by spring return. Designed foer minimum flow resistance, the internal area is greater than the connecting ports &endash; reducing pressure drop to a minimum. Unloading valves Types 14330 (1/2in BSP), 14320 (3/4in BSP) and 14430 (1 in BSP) general purpose unloading valves are of the locked in pressure type, suitable for pressures up to 380 bar (5,500 psi) and flows up to 270 litres (60 gals) per minute. Features include a totally enclosed design, and low flow resistance through the by-pass port. |
Pneumatic unloading/diverting valves This range is based on the above series of totally enclosed unloading valves. An air cylinder replaces the main spring, and allows remote setting and operation from any compressed air source at pressures of up to 7 bar. Pneumatic operation enhances the performance of the standard spring valve, providing additional functions. The valve is normally held open by an internal spring with flow diverted to the by-pass port, with the service outlet closed by the service check valve. When air pressure is applied, the by-pass port is closed and flow is diverted to service.Adjustment of the air pressure can cause the valve to act as a flow regulator when there is pressure in the service line. For example, flow from a jetting nozzle may be controlled by adjustment of the air supply.The pneumatic valve performs the same functions of safety relief and unloading as does the standard spring operated valve. The characteristics of compressed air are similar to those of a fixed spring, and will allow the valve to unload when used with a total shut jetting gun. |