Valve entry terminology has two basic parts,which is terminology of valve industry and valve parts.After study these two parts,then you will have a good knowledge of valve，especially widely used for fully welded ball valve.
1. Strength performance
The strength performance of the valve refers to the ability of the valve to withstand the pressure of the medium. The valve is a mechanical product that can withstand internal pressure, so it 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, and it is the most important technical performance index of the valve.
There are three sealing positions of the valve: the contact between the opening and closing member and the two sealing surfaces of the valve seat; the fitting of the packing with the valve stem and the stuffing box; and the connection between the valve body and the valve cover. The previous leak is called internal leakage, which is commonly known as improper closing, which will affect the valve’s ability to intercept the medium.
For shut-off valves, internal leakage is not allowed. The latter two leaks are called external leaks, that is, the medium leaks from the inside of the valve to the outside of the valve. Leakage can cause material loss, pollute the environment, and 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 (the pressure difference between the front and rear of the valve), that is, the valve has a certain resistance to the flow of the medium, and the medium needs to consume a certain amount of energy in order to overcome the resistance of the valve.
From the perspective of energy conservation, when designing and manufacturing the valve, it is necessary to reduce the resistance of the valve to the flowing medium as much as possible.
4. Opening and closing force and opening and closing moment
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 make a certain sealing specific pressure between the opening and closing member and the two sealing surfaces of the hair seat. The frictional force of other friction parts must be applied with 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 are changed. Its maximum value is at the final instant of closing or the initial instant of opening. Valves should be designed and manufactured 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 conditions have special requirements for the opening and closing speed. If required, it should be opened or closed quickly to prevent accidents, and some require to be closed slowly to prevent water hammer. 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 media parameters. Functional sensitivity and reliability are very important technical performance indicators for valves that have specific functions, such as throttle valves, pressure reducing valves, regulating valves, and other valves that are used to adjust media parameters.
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 openings and closings that can guarantee the sealing requirements, and it can also be expressed by the use time.
8.Type
Classification of valves by application or main structural feature.
9.Model
Number the valve by type, transmission method, connection type, structural characteristics, valve seat sealing surface material, and nominal pressure.
10.Connection size
Dimensions of valve and pipe connection.
11.Main dimensions
Valve opening and closing height, handwheel diameter, and connection dimensions.
12.connection form
Various methods used to connect the valve to the pipeline or machinery and equipment (such as flange connection \ thread connection \ weld connection, etc.).
13.Seal test
Test to check the performance of the opening and closing parts and the valve body sealing pair.
14. Upper seal test
Test to verify the sealing performance of the valve stem and bonnet sealing pair.
15. Sealing test pressure
Pressure specified during valve sealing test.
16.Applicable medium
The applicable medium of the valve. Such as heating ball valves and gas ball valves.
17.Applicable temperature
Temperature range of the medium to which the valve is suitable.
18. Sealing surface
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
A general name for a part used to cut off or regulate the flow of media, such as a gate in a gate valve, a disc in a throttle valve, and so on.
20. Filling
Packing stuffed into a stuffing box (or stuffing box) to prevent media from leaking from the valve stem.
21. Filling pad
Parts that support the packing and keep the packing sealed.
22. Stents
Parts on the valve cover or valve body to support the stem nut and the transmission mechanism.
23.connection slot size
Structural dimensions of the assembly and connection part of the opening and closing member and the valve stem.
24.runner area
Refers to the minimum cross-sectional area (but not the “curtain” area) between the valve inlet end and the seat sealing surface. It is used to calculate the theoretical displacement without any resistance.
25. Flow characteristics
Under steady flow conditions, when the inlet pressure and other parameters are not changed, the outlet pressure of the pressure reducing valve is a function of flow.
26. Worm gear transmission
Device for opening and closing or adjusting valve with worm gear mechanism.
27. Pneumatic device
Actuator that opens or closes or regulates the valve with air pressure.
28. Hydraulic device
Drive device that opens and closes or adjusts valve with hydraulic pressure.
29. Hot condensate capacity
The maximum amount of condensate that can be drained out of a trap at a given pressure difference and temperature.
30. Steam leakage
The amount of fresh steam leaked by the trap per unit time.