Do You Know All The 100 Professional Terms For Valves

Publish Time: 08/20 2024 Author: Site Editor Visit: 93

Basic professional terms

1. Strength performance

The strength performance of Lined Valve refers to the ability of the valve to withstand the pressure of the medium. The valve is a mechanical product that withstands internal pressure, so it must have sufficient strength and rigidity to ensure long-term use without cracking or deformation.

2. Sealing performance

The sealing performance of the valve refers to the ability of each sealing part of the valve to prevent the leakage of the medium. It is an important technical performance indicator of the valve.

There are three sealing parts of the valve: the contact between the opening and closing parts and the two sealing surfaces of the valve seat; the matching part of the packing and the valve stem and the stuffing box; the connection between the valve body and the valve cover. The leakage of the first one is called internal leakage, which is usually called loose closure, which will affect the ability of the valve to cut off the medium.

For cut-off valves, internal leakage is not allowed. The leakage of the last two parts is called external leakage, that is, the medium leaks from the inside of the valve to the outside of the valve. External leakage will cause material loss, pollute the environment, and cause accidents in serious cases.

For flammable, explosive, toxic or radioactive media, external leakage is even more unacceptable, so the valve must have reliable sealing performance.

3. Flowing medium

After the medium flows through the valve, pressure loss will occur (i.e., the pressure difference before and after the valve), that is, the valve has a certain resistance to the flow of the medium, and the medium will consume a certain amount of energy to overcome the resistance of the valve.

Considering energy conservation, when designing and manufacturing valves, the resistance of the valve to the flowing medium should be reduced as much as possible.

4. Opening and closing force and opening and closing torque

Opening and closing force and opening and closing torque refer to the force or torque that must be applied to open or close the valve.

When closing the valve, it is necessary to form a certain sealing pressure ratio between the opening and closing parts and the two sealing surfaces of the valve seat, and at the same time, it is necessary to overcome the friction between the valve stem and the packing, between the threads of the valve stem and the nut, at the end support of the valve stem and other friction parts, so a certain closing force and closing torque must be applied. During the opening and closing process of the valve, the opening and closing force and opening and closing torque required are variable, and the maximum value is at the final moment of closing or the initial moment of opening. When designing and manufacturing valves, efforts should be made to reduce their closing force and closing torque.

5. Opening and closing speed

The opening and closing speed is expressed by the time required for the valve to complete an opening or closing action. Generally, there are no strict requirements for the opening and closing speed of valves, but some working conditions have special requirements for the opening and closing speed, such as some require rapid opening or closing to prevent accidents, and some require slow closing to prevent water hammer, etc. This should be considered when selecting the valve type.

6. Action sensitivity and reliability

This refers to the sensitivity of the valve to respond to changes in medium parameters. For valves such as throttle valves, pressure reducing valves, and regulating valves used to adjust medium parameters, as well as valves with specific functions such as safety valves and steam traps, their functional sensitivity and reliability are very important technical performance indicators.

7. Service life

It indicates the durability of the valve, is an important performance indicator of the valve, and has great economic significance. It is usually expressed in terms of the number of openings and closings that can ensure the sealing requirements, or it can be expressed in terms of usage time.

8. Type

Classification of valves by purpose or main structural features

9. Model

Numbering of valves by type, transmission mode, connection form, structural characteristics, valve seat sealing surface material, and nominal pressure.

10. Connection dimensions

Dimensions of the connection between the valve and the pipeline

11. General dimensions

Valve opening and closing height, handwheel diameter and connection dimensions, etc.

12. Connection type

Various ways of connecting the valve to the pipeline or machinery and equipment (such as flange connection, threaded connection, welding connection, etc.).

13. Seal test

Test to check the performance of the opening and closing parts and the sealing pair of the valve body.

14. Back seal test

Test to check the sealing performance of the valve stem and the valve cover sealing pair.

15. Seal test pressure

Pressure specified when the valve is tested for sealing.

16. Suitable medium

Medium that the valve can be used for.

17. Suitable temperature

Temperature range of the medium that the valve is suitable for.

18. Sealing face

Two contact surfaces that tightly fit the opening and closing parts and the valve seat (valve body) and act as a seal.

19. Opening and closing parts (disc)

A general term for a part used to cut off or regulate the flow of media, such as the gate in a gate valve, the valve disc in a throttle valve, etc.

20. Packing

The filler that is put into the stuffing box (or stuffing box) to prevent the medium from leaking from the valve stem.

21. Packing seat

Parts that support the packing and keep the packing sealed.

22. Gland

Parts used to compress the packing to achieve sealing.

23. Yoke

Parts on the valve cover or valve body used to support the valve stem nut and transmission mechanism.

24. Dimension of connecting channel

Structural dimensions of the assembly connection between the opening and closing parts and the valve stem.

25. Flow area

Refers to the minimum cross-sectional area between the inlet end of the valve and the sealing surface of the valve seat (but not the "curtain" area), which is used to calculate the theoretical displacement without any resistance.

26. Flow diameter

Corresponds to the diameter of the flow area.

27. Flow characteristics

Under a stable flow state, when the inlet pressure and other parameters remain unchanged, the functional relationship between the outlet pressure and flow of the pressure reducing valve.

28. Flow characteristics deviation

Under a stable flow state, when the inlet pressure and other parameters remain unchanged, the change in outlet pressure caused by the change in the flow of the pressure reducing valve.

29. General valve

Valves commonly used on pipelines in various industrial enterprises.

30. Self-acting valve

Valves that act automatically by relying on the ability of the medium (liquid, air, steam, etc.).

31. Actuated valve

Valves that are operated manually, electrically, hydraulically or pneumatically.

32. Hammer blow handwheel

A handwheel structure that uses impact force to reduce the valve operating force.

33. Wormgear actuator

A device that uses a worm gear mechanism to open, close or adjust a valve.

34. Pneumatic actuator

A driving device that uses air pressure to open, close or adjust a valve.