What are the components of a valve?

author: ATHENA GROUP

2023-07-22

A valve is a device used to control fluid flow and is widely used in various industrial fields. The structural composition of the valve refers to the various parts of the valve, including the valve body, valve bonnet, valve stem, seat, seal and so on. The structure of the valve will be described in detail below:

Body:The valve body is the main part of the valve, it is the shell of the valve, used to accommodate the internal components of the valve. The body material is usually cast iron, carbon steel, stainless steel, such as A216 WCB, A217 WC6,A217 WC9,A350 LCB,SS304, SS316 and so on.
Refer to diagram 1 part 1 which is the body of the valve;Refer to diagram 2 part 1 which is the body of the valve;Refer to diagram 3 part 1 which is the body of the valve;Refer to diagram 4 part 1 which is the body of the valve

Bonnet:The valve bonnet is the upper part of the valve that covers the internal components of the valve. The valve cover is usually made of the same material as the valve body, but there are some special cases that require to use different materials.
Refer to diagram 1 part 7 which is the bonnet of the valve;Refer to diagram 2 part 8 which is the bonnet of the valve;Refer to diagram 3 part 8 which is the bonnet of the valve;Refer to diagram 4 part 14 which is the bonnet of the valve.

Stem: The stem is the main moving part of the valve, which is connected to the valve handle/handwheel/gear and the valve internals, and is used to control the switch of the valve. The stem material is usually stainless steel or ductile iron, such as SS316,SS304,DI.
Refer to diagram 1 part 3 which is the stem of the valve;Refer to diagram 2 part 4 which is the stem of the valve;Refer to diagram 3 part 4 which is the stem of the valve;Refer to diagram 4, there is no stem for check valve, but hinge pin in part 8.

Wedge: The wedge is the opening and closing part of the gate valve, the opening and closing of the gate valve and the sealing performance and life are mainly dependent on the wedge, which is the key pressure control part of the gate valve. According to the structure of the ram can be divided into two categories- flexible wedge and solid wedge.
Refer to diagram 1 part 2 which is the wedge of the gate valve;Refer to diagram 2 part 3 which is the wedge of the gate valve;Refer to diagram 3 part 3 which is the wedge of the gate valve;Refer to diagram 4 part 3 which is the wedge of the gate valve

Seat: The seat is the sealed part of the valve, which is used in conjunction with the stem and valve internals to control the flow of media. The material of the valve seat is usually carbon steel, stainless steel, etc. Such as A105, SS304, SS316.
Refer to diagram 1&3 , seat is integral with body, so don’t marked separately for this gate valve sample. But you can see diagram 2&4, part 2, which is seat separately.

Seal: The valve seal is a key part of the valve, which is used to ensure the sealing performance of the valve. The sealing material is usually rubber, teflon, graphite and so on.
Refer to diagram 1 part 8 which is the packing of valve;Refer to diagram 2 part 10 which is the packing of valve;Refer to diagram 3 part 10 which is the packing of valve;Refer to diagram 4 there is no packing of valve, but you can see gasket in part 12.

Driving device:The valve driving device refers to the device used to control the opening and closing of the valve and adjust the lifting of the valve. In different industrial fields, the types and specifications of valves and drives used are also different. The function of these valve drives is to ensure the normal operation of the valve and improve production efficiency.

For manual valve, should be lever( for small ball valve, butterfly valve etc.), handwheel (for small size gate valve, globe valve etc.),gear(for bigger size gate valve, globe valve etc.); Simple and reliable operation, low cost. Its principle is to manually rotate the radial rim of the valve through manual operation, drive the up and down movement or rotation of the gate or ball, and control the flow of the medium. Although its control mode is relatively primitive, in some small industrial enterprises and personal use, manual valve drive devices are still a more practical choice.

For valves with actuator, it should be pneumatic actuator, electric actuator(It uses the motor to drive the worm transmission mechanism, which drives the opening and lifting of the valve, replacing the manual operation. This kind of drive device is widely used in some occasions requiring high automation control and precision, such as chemical industry, water conservancy engineering, metallurgy industry and electric power industry. The electric drive device is stable and reliable, avoiding accidents and quality problems caused by improper operation or manual monitoring negligence, and improving the valve switching speed and operating efficiency.), hydro. Actuator (Hydraulic valve driving device is a new type of driving device with the development of hydraulic technology in recent years. In the hydraulic valve driving device, the motor pushes the hydraulic oil into the hydraulic cylinder through the hydraulic pump, and the piston of the hydraulic cylinder rises and pushes the hook claw to realize the opening of the valve; The valve is closed when the hydraulic oil is returned to the tank. Hydraulic valve drive device is suitable for all kinds of large valves, with large opening and closing force, easy control and other characteristics, and more energy saving than electric drive device.)etc.

Refer to diagram 1 part 16 which is the handwheel of the valve;Refer to diagram 2 part 16 which is the gear of the valve;Refer to diagram 3 part 17 which is the handwheel of the valve;Refer to diagram 4 there is no any driving device for check valve.

The above is the main structural composition of the valve, different types of valves have some special structural composition, such as the ball of the ball valve, the disc of the butterfly valve, etc. The structural composition of the valve has an important impact on the performance and service life of the valve, so it is necessary to select the right valve according to the specific application and medium.Valve with alloy steel surfacing sealing surface, wear resistance, corrosion resistance, long life.