Valves are pipeline attachments used to open and close lines, control flow, and regulate and control the parameters (temperature, pressure, and flow) of the medium being transported.  This article will introduce basic terminology and definitions of industrial valves for new beginners in this industry

1, Shell strength performance

The strength properties of a valve are the ability of the valve to withstand the pressure of the medium. Valves are mechanical products that withstand internal pressure and must therefore 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 the sealing parts of the valve to prevent the leakage of the medium. It is the most important technical performance index of the valve.

There are three sealing parts of the valve: the contact between the sealing surface of the opening and closing parts and the valve seat; the joint of the packing with the valve stem and the stuffing box; the connection between the valve body and the valve cover. The leak in the former place is called endoleak, which is commonly referred to as the lack of tightness, which will affect the ability of the valve to cut off the medium.

For shut-off valves, internal leakage is not allowed. The latter two leaks are called external leaks, ie the medium leaks from the valve to the outside of the valve. External leakage can cause material loss, pollute the environment, and cause accidents in severe cases.

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

3, flowing media

When the medium flows through the valve, pressure loss (both pressure difference before and after the valve) is generated, that is, the valve has a certain resistance to the flow of the medium, and the medium consumes a certain amount of energy in order to overcome the resistance of the valve.

In terms of energy conservation, when designing and manufacturing valves, it is necessary to reduce the resistance of the valve to the flowing medium as much as possible.

4, opening and closing torque

The opening and closing torque refer to the force or moment that must be applied when the valve is opened or closed.

When closing the valve, it is necessary to form a certain sealing specific pressure between the opening and closing parts and the sealing surface of the bearing seat, and at the same time overcome the between the valve stem and the packing, between the thread of the valve stem and the nut, and at the end of the valve stem and The friction of other friction parts must be applied with a certain closing force and closing torque. During the opening and closing process, the required opening and closing force and opening and closing torque are changed. The maximum value is the final moment or opening of the closing. The initial moment. When designing and manufacturing valves, it is desirable 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 is no strict requirement for the opening and closing speed of the valve, but some working conditions have special requirements for the opening and closing speed. If some requirements are quickly opened or closed, in case of accidents, some requirements are required to be slowly closed to prevent water hammer, etc. This should be considered when selecting the valve type.

6, motion sensitivity and reliability

This refers to the sensitivity of the valve to the corresponding changes in the media parameters. For valves with regulating functions such as throttle valves, pressure reducing valves, regulating valves, etc., as well as valves with special functions such as safety valves and traps, the functional sensitivity and reliability are important technical performance indicators.

7, the service life

It indicates the durability of the valve, is an important performance indicator of the valve, and has great economic significance. Usually indicated by the number of opening and closing times that can guarantee the sealing requirements, it can also be expressed by the use time.

8, type

Classification of valves by use or main structural features

9, model

Numbering the valve by type, transmission, connection type, structural characteristics, seat sealing surface material and nominal pressure.

10, connection dimensions

Valve and pipe joint size

11, general dimensions

Valve opening and closing height, handwheel diameter and connection size.

12, type of connection

The various ways in which the valve is connected to the pipe or machine (eg flange connection / threaded connection / welded connection, etc.).

13, seal test

Tests for the performance of the opening and closing parts and the valve body seal pair.

14, back seal test

Test the sealing performance of the valve stem and bonnet seal pair.

15. Seal test pressure

The pressure specified by the valve during the seal test.

16, suitable medium

The medium to which the valve can be applied.

17, suitable temperature

The temperature range of the medium to which the valve is applied.

18, sealing face

The opening and closing member is in close contact with the valve seat (valve body), and serves as a sealing contact surface.

19, disc

A general term for a part used to cut off or regulate the flow of a medium, such as a gate in a gate valve, a valve flap in a throttle valve, and the like.

20, packing

Load the stuffing box (or stuffing box) to prevent the media from leaking from the valve stem.

21, packing seat

A part that supports the packing and keeps the packing sealed.

22, packing gland

A part that is used to compress the packing to achieve a seal.

23, yoke

A part used to support the stem nut and transmission mechanism on the bonnet or valve body.

24, dimension of connecting channel

The structural dimensions of the joint between the opening and closing member and the valve stem assembly.

25, flow area

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

26, flow diameter

Corresponds to the diameter of the runner area.

27, flow characteristics

In the steady flow state, when the inlet pressure and other parameters are constant, the outlet pressure of the pressure reducing valve is a function of the flow rate.

28. Flow characteristics derivation

In the steady flow state, when the parameters such as the inlet pressure are constant, the change in the outlet pressure caused by the change in the flow rate of the pressure reducing valve.

29, general valve

Valves commonly used in pipelines in various industrial enterprises.

30, self-acting valve

A valve that acts on its own depending on the capabilities of the medium (liquid, air, steam, etc.).

31. Actuated valve

Valves that are operated by manual, electric, hydraulic or pneumatic pressure.

32. Hammer blow handwheel

A handwheel structure that utilizes a striking force to relieve valve operating forces.

33, worm gear actuator

A device that opens or closes or adjusts a valve with a worm gear mechanism.

34, pneumatic actuator

Use the pneumatic pressure to open or close or adjust the drive of the valve.

35, hydraulic actuator

Use hydraulic pressure to open or close or adjust the valve's drive.

36. Hot condensate capacity 

The maximum amount of condensate that can be discharged from the trap in a given differential pressure and temperature

37. Steam loss

The amount of fresh steam leaking out of the trap per unit time.

If you are interested in more information, freely contact us and discuss with us via sales@jhflow.com