22

2020

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07

A collection of 100 professional terms for valves

Author:


The strength performance of the valve refers to the valve's ability to withstand the pressure of the medium. Valves are mechanical products that withstand internal pressure, so they must have sufficient strength and rigidity to ensure long-term use without rupture or deformation.

1. Strength performance

The strength performance of the valve refers to the valve's ability to withstand the pressure of the medium. Valves are mechanical products that withstand internal pressure, so they must have sufficient strength and rigidity to ensure long-term use without rupture or deformation.

 

2. Sealing performance

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

 

There are three sealing parts of the valve: the contact point between the opening and closing parts and the two sealing surfaces of the valve seat; the matching point between the packing, the valve stem and the stuffing box; and the connection point between the valve body and the valve cover. The first leakage is called internal leakage, which is commonly referred to as lax sealing. It will affect the valve's ability to cut off the medium.

 

For cut-off valves, internal leakage is not allowed. The latter two leaks are called external leakage, that is, the medium leaks from inside the valve to outside the valve. Leakage will cause material loss, pollute the environment, and even cause accidents in severe cases.

 

For flammable, explosive, toxic or radioactive media, leakage is not allowed, so the valve must have reliable sealing performance.

 

 

3. Flowing medium

After the medium flows through the valve, there will be a pressure loss (that is, 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.

 

From the perspective of 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

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

 

When closing the valve, it is necessary to form a certain sealing ratio between the two sealing surfaces of the opening and closing parts and the hair seat. At the same time, it is necessary to overcome the pressure between the valve stem and the packing, the thread between the valve stem and the nut, the end support of the valve stem and the The friction force of other friction parts must apply a certain closing force and closing torque. During the opening and closing process of the valve, the required opening and closing force and opening and closing torque change, and its maximum value is at the final instant of closing or The first 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. For example, 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 accordingly to changes in media 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 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 by the number of opening and closing times that can ensure the sealing requirements, or it can also be expressed by the use time.

 

8. Type

Classification of valves according to use or main structural features

 

9. Model

The valves are numbered according to type, transmission mode, connection form, structural characteristics, valve seat sealing surface material and nominal pressure.

 

10. Connection dimensions

Dimensions of valve and pipe connections

 

11. Main dimensions (general dimensions)

The opening and closing height of the valve, the diameter of the handwheel and the connection size, etc.

 

12. Type of connection

Various methods used to connect valves to pipelines or machinery and equipment (such as flange connection\threaded connection\welded connection, etc.).

 

13. Seal test

A test to check the performance of opening and closing parts and valve body sealing pairs.

 

14. Back seal test

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

 

15. Seal test pressure

The pressure specified when the valve is tested for sealing.

 

16. Suitable medium

The media that the valve can be used for.

 

17. Suitable temperature

The temperature range of the medium suitable for the valve.

 

18. Sealing face

The opening and closing parts are in close contact with the valve seat (valve body) and serve as two contact surfaces for sealing.

 

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 plate in a gate valve, the valve disc in a throttle valve, etc.

 

20. Packing

Filling material placed in 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. Packing gland (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

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

 

26. flow diameter

Diameter corresponding to the flow channel area.

 

27. flow characteristics

Under steady flow conditions, when the inlet pressure and other parameters remain unchanged, the functional relationship between the outlet pressure of the pressure reducing valve and the flow rate.

 

28. Flow characteristics derivation

Under steady flow conditions, when the inlet pressure and other parameters remain unchanged, the change in outlet pressure caused by changes in the flow rate of the pressure reducing valve.

 

29. General valve

Valves commonly used on pipelines in various industrial enterprises.

 

30. Self-acting valve

A valve that operates on its own based on the ability of the medium (liquid, air, steam, etc.) itself.

 

31. Actuated valve

Valves operated manually, electrically, hydraulically or pneumatically.

 

32. Hammer blow handwheel

A handwheel structure that utilizes impact force to reduce valve operating force.

 

33. Worm gear 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.

 

35. Hydraulic actuator

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

 

36. Hot condensate capacity

Under a given pressure difference and temperature, the trap can discharge a larger amount of condensate.

 

37. Steam loss

The amount of fresh steam leaked from the trap per unit time.