What is a high-pressure gate valve?
A high-pressure gate valve is designed for use in high-pressure applications. This valve is connected to the pipe using bolts and nuts or by using welding. These two methods produce a high-strength joint between the valve and pipe leading to fluid flow without leakage. The valve operates by using a component known as a disc. The disc moves up and down to start and stop fluid flow. High pressure gate valve manufacturers make this valve from high-strength metallic materials such as stainless steel and carbon steel. These materials have a high melting point, allowing the valve to operate comfortably at high pressure and temperatures. The valve is operated using a manual handwheel. It can also be operated using electric, pneumatic, and hydraulic actuators. It is best suitable for shut-off applications. When used for throttling flow, the valve disc wears out rapidly or is damaged due to high pressure. The valve is bi-directional, allowing fluid flow in either direction.
Figure: High-pressure gate valve.
Components of a high-pressure gate valve
Actuator
The actuator is the source of power that operates the valve. It can be a manual handwheel or an electric, pneumatic, or hydraulic actuator. The manual handwheel is where the valve operator applies force to open or close the valve. The electric actuator uses an electric motor to operate. The pneumatic actuator uses compressed air, while the hydraulic actuator employs hydraulic fluid.
Stem/shaft
The stem, also known as the shaft, is a metallic component connecting the valve actuator to the disc. It transmits power from the actuator to the disc. High-pressure gate valve manufacturers design the stem to be either rising or non-rising. The rising stem rises above the valve when the valve is started. It has the advantage of notifying the operator when the valve is fully opened. The non-rising stem does not go above the valve and is thus designed with an indicator that helps the operator know when to close or open the valve.
Valve disc
The valve disc, or the gate, stops or starts the fluid flow. It gets the power to close/open from the valve actuator via the stem.
Seats
Seats are components that create a perfect seal between the body and valve disc when the disc closes flow to prevent leakage. The valve uses two seats integrated into the valve body.
Valve body
The valve body is a heavy-duty component that covers valve seats and discs. It also helps seal internal fluid against atmospheric pressure to ensure no pressure loss or leakage. Depending on the type of valve-pipe connection, the valve body comes with ends for welding or with flanges. A valve body with flanges is connected to the pipe using bolts and nuts. A valve connected to the pipe using the welding method comes with butt weld ends.
Bonnet
Bonnet is a component that is mounted on top of the valve body. The bonnet and body are made of the same metallic material. The bonnet seals the interior of the valve against pressure loss as well as prevent fluid leakage and entry of dirt. High-pressure gate valve manufacturers connect the bonnet to the body using bolts or pressure seals.
Packing
Packing is used to seal pressure between the valve stem and the bonnet. It also ensures fluid does not leak through the stem. The packing is replaced after a certain period since it wears out or loosens.
Figure: Components of a high-pressure gate valve.