A gate valve is a measuring valve designed to minimize the pressure by dropping the valve into the open position to stop fluid flow. Gate valves are ideal for use as shut-off valves if required. However, they have low-pressure limitations and are not optimal for applications requiring cleanliness and hygienic conditions. If needed, valves with a throttle valve can be used, but this is not recommended as the window’s vibrations during the throttling process can cause the seat window’s erosion.
Large gate valves offer a valve-bypass line that reduces the seat load and allows the valve to be opened. However, friction under high pressure can become a problem. When the seat load of a large slider floats, the seat becomes very high, and the high liquid pressure and friction of the seat make it challenging to lift the pane from the closed position.
The effort required to open and close a large gate valve can be reduced using a gear drive. Spool valves can be automated with electric actuators, or their operation can be accelerated by hydraulic, pneumatic, or linear actuators. The design can have a significant impact on the performance of the actual valve. Building regulations may require a valve to be installed in front of certain appliances (e.g., an instantaneous heater).
A valve consists of three main parts: the valve body, the valve’s seat, the disc shaft, and the packing hood. A pipe or flange connects the two ends of the valve with bolts and nuts. The valve shaft and the nut are the mounts of the valve cover. They turn to lift and open the gate and lower and close it with the valve shaft.
Gate valves refer to the gate valve’s valve closing element, which moves vertically along the centerline of the passage constructed by the valve body, hood, stem, door seal, packaging, handwheel, gearbox, and other components. This type of construction uses valve handles and threaded drives to lubricate, but the degree of opening and closing a door is different.
Like a hose, a slider has a rectangular sealing element. The closure element has a circular opening that corresponds to the entire flow range through the slider and is lowered to expose the flow gap. This construction puts the surface of the door in contact with the door at all times.
The valve is self-cleaning because it passes through the seat ring every time it is opened or closed. The gate at this point is a piece of metal. It can be raised or lowered by a rotating thread shaft.
A rising shaft is attached to the gate to give an optical indication of the valve position. Spool valves can have either a rising or non-rising shaft. Non-ascending trunks are threaded through the gate’s upper part, with a pointer thread indicating the top position. These handles are more suitable for applications where vertical space is limited.
Slides are available in a variety of designs that use different technologies to meet additional application requirements. Engine hoods protect the inner parts of a slider. Engine hoods are screw-and-bolt valve bodies that produce a leak-free seal. They are removable and can be repaired for maintenance.
The bolt is connecting the lower valve body to the upper bonnet. There are two stainless steel sliders with flanged ends. They will be installed in new extinguishing hydrants. The visible thread is the valve shaft, which protrudes from the handwheel shown below, and the valves rise from the valve shaft.
A slider is designed as a full bore for pigs, which means that when opened, the pig fits easily into the tube that fits through. The pig is closed to fit the diameter of the pipe through which it passes. Since it is a “piggable” valve, it has little resistance to opening and does not affect the liquid’s pressure that flows through it.