The gate valve is a device that is designed to operate as shutoff valves in various production lines. The mechanism is used on main pipelines to block the movement of dirty and sludge waters, bulk materials, paper and pulp media.
The devices are used in sewerage systems, sewage treatment plants, in the energy, pulp and paper, mining, food, chemical and other industries and municipal services. The gate valve differs from other similar devices by the design of the locking element.
In this type of fixture, a metal plate or wedge is used, which is able to cut inclusions in liquids flowing inside the valve. Stop valves are used to completely block the flow of any medium in the pipeline.
The knife gate valve can be installed with a vertically located spindle, with the flywheel up only on horizontal pipelines. Each shut-off valve can either be fully closed or open. The use of locking devices for throttling (incomplete closing or opening) is not allowed.
Electric gate valve allows to mechanize the process of the device. It is used to maintain flows with a low pressure drop. Devices allow to block access to equipment and have dimensions from 10 mm to 2.7 meters. Large dimensions have throttle devices.
Shutoff valves consist of a steering wheel and a disk, which is controlled by a helical rod moving at right angles to the flow up or down. In the closed position, the disk to block the flow abuts against two surfaces. To keep the fluid in the pipes and prevent leaks, an oil seal is used, which comes complete with sealing materials.
Despite the breadth of application, the gate valve is not always able to carry out the task. At low pressures, the device’s efforts are insufficient to seal the system; in such cases, lubricated taps or wedge gate valves are installed .
Shut-off valves depending on the environment of use are made of various materials. The gate valve, designed for operation in catalytic lines, is made of low alloy or stainless steel. The use of vibration-sealing lining and the abandonment of the use of austenitic steels are associated with aggressive conditions and significant pressure drops.
During the flushing of pipelines with water, the mass gate valves may cause a small leak in the gaskets. However, they should not be tightened, since the devices are not designed to work with water, and their tightness can only be checked in conditions of denser flows.
Devices with an electric or hydraulic drive are usually used in the operation of technological piping of pumping stations, systems designed for receiving and starting separators.