Massive Selection for Main Safety Valve - Steam extraction check valve – Convista

Detail

Used for steam, water and other non-corrosive medium pipes of pumping or other systems in a power plant, the product is an indispensable accessory of thermal generator set to protect safe operation of the steam turbine. As a device to prevent reverse flow of medium, the valve can close rapidly and tightly to ensure separate the steam turbine rapidly and provide steam turbine or pumping system with utmost protection after the pneumatic device part receives reversed liquid flow signal in case the water supply heater has super high-water level. 

Advantages

1. The valve seat and body adopt integrated structure, with 25° included angle between the valve seat and the branch pipe. On the premise of increasing no flow resistance, closing stroke is shortened to better ensure rapid closing and sealing performance of the valve and the valve closing stroke duration is less than 0.5s.
2. With swing type structure, the valve disc is supported by the valve stem in the valve body. Both ends of the valve stem are supported by the guiding sleeve on the valve body. With Stellite alloy build-up welding, the sealing surface is not less than 3mm after processing and its hardness has certain hardness difference comparing with valve seat hardness.
3. The valve is installed with some rotary pneumatic actuators. When the pneumatic actuator is at its opening state, the valve disc is not opened or closed by pneumatic actuator, capable of rotating freely; the valve can close automatically even the actuator does not operate. At its closing state, the pneumatic actuator exerts auxiliary force on the valve disc to ensure closing duration and sealing reliability of the valve.
4. The valve bonnet adopts middle flange structure and the sealing gasket adopts winding gasket for sealing, featuring reliable sealing and convenient disassembly.
5. For a valve with lower working pressure, a damp heavy hammer is loaded on the valve stem to balance gravitational torques of valve disc and other closing parts; capable of ensuring steady opening of valve disc and reduced vibration during forward flow of low-pressure medium.
6. With streamline design, inner cavity of the valve body has lowered valve resistance and strong flow capacity.
7. With angular displacement stroke switch, the pneumatic actuator can monitor its on-off state remotely.
8. The valve structure has heavy hammer or heavy hammer free types.
9. The valve has manual test device for the pneumatic actuator. Online micro-operation test of the cylinder is realized by manual and throttle valves to prevent long-term no-operation of the valve and the cylinder at working state, providing verification reference for normal working.