What is a high-pressure globe valve?
A high-pressure globe valve is a valve that is specially designed for use in high-pressure applications. Construction of the valve employs high-strength materials and reliable manufacturing methods like forging and casting. High-pressure globe valve manufacturers make these valves using materials such as ductile iron, carbon steel, and stainless steel. These materials have good thermal and mechanical properties making the valve suitable for high-pressure and high-temperature applications. The valve operates using a component known as a disc that closes and opens fluid flow as necessary. These valves are ideal for shut-off and throttling applications. The mechanical design of these valves makes them prone to high pressure drop. Operation of the valve is done using a manual handwheel or actuators. As such, the valve can operate manually, be automated, or semi-automated, depending on user preferences and industrial requirements.
Figure: High pressure globe valve.
Components of a high-pressure globe valve
Actuator
The actuator in these valves is mostly handwheel. Other valves operate using an electric and pneumatic actuator. The choice of the actuator depends on several factors, among them industry requirements, knowledge to repair, and torque requirements. The work of the actuator/handwheel is to provide the torque needed to operate the valve to allow or close the fluid flow. The operator applies a torque on the handwheel for manual valves to operate.
Stem
The stem is a shaft that connects the handwheel or actuator to the valve disc. Like in other mechanical machines, the stem/shaft transmits torque from the handwheel to the valve disc. It also helps to transform rotary motion from the handwheel to linear motion. The stem comes with threads that enhance linear motion from the rotary motion.
Valve disc
The valve disc is a component that controls fluid flow through the valve. It gets the power to control fluid flow from the handwheel through the valve stem. The disc material’s choice dictates the fluid type the valve can control. Some liquids are corrosive, and thus the disc needs to be made of corrosion-resistant material such as stainless steel.
Seats
There are two seats in this valve. The seat is a component that helps the disc seal off fluid flow and leakage when the valve is closed. The valve can have the seats screwed into the valve body or integrated into the valve body. Other valves have back seats on the valve bonnet. The back seats help to enhance the tight seal between the stem and bonnet to stop the pressure build-up against the valve packing.
Body
The body is an external component that covers the internal parts of the valve. It also contains the inlet and outlet ports of the valve. The body is usually thick to ensure its ability to withstand high fluid pressure and also safeguard internal parts against impact damage. The body has flanges with holes that allow connection to the pipe using bolts and nuts.
Bonnet
Bonnet is another exterior component mounted on top of the valve body. The bonnet helps contain top interior parts and seals off fluid leakage. High-pressure globe valve manufacturers connect the body and bonnet using bolts or pressure seals.
Gland packing
Gland packing is a component that uses seals between the stem and bonnet to prevent fluid leakage. It also ensures no dirt enters the valve.
Figure: Components of a high-pressure globe valve.