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Professional terminology for getting started with valves, these must be known!

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Valves are pipeline accessories used to open and close pipelines, control flow direction, adjust and control the parameters (temperature, pressure and flow) of the conveyed medium. You may wish to read more about the professional terminology of the valve industry!

Valves are pipeline accessories used to open and close pipelines, control flow direction, adjust and control the parameters (temperature, pressure and flow) of the conveyed medium. You may wish to read more about the professional terminology of the valve industry!

PART. 1
Basic professional terminology
1. Strength performance The strength performance of a valve refers to the valve's ability to withstand medium pressure. 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 index 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. Flow 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 consumes 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. 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, which represents 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 (type) classifies valves according to their uses or main structural features. 9. Model (model) numbers valves according to type, transmission mode, connection form, structural characteristics, valve seat sealing surface material and nominal pressure. 10. Connection dimensions: the size of the connection between the valve and the pipe. 11. General dimensions: the opening and closing height of the valve, handwheel diameter, connection dimensions, 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 (seal test) is a test to test the performance of the opening and closing parts and the valve body sealing pair. 14. Back seal test is a test to test the sealing performance of the valve stem and valve cover sealing pair. 15. Seal test pressure (seal test pressure) is the pressure specified when the valve is tested for sealing. 16. Suitable medium: The medium that the valve can be used for. 17. Suitable temperature: The temperature range of the medium suitable for the valve. 18. Sealing face (sealing face) The opening and closing parts are closely attached to the valve seat (valve body) and are two contact surfaces that serve as seals. 19. Disc is 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 is put into the stuffing box (or stuffing box) to prevent the medium from leaking from the valve stem. 21. Packing seat (packing seat) supports the packing and keeps the packing sealed. 22. The packing gland (gland) is a part used to compress the packing to achieve sealing. 23. The bracket (yoke) is on the valve cover or valve body and is used to support the valve stem nut and transmission mechanism parts. 24. Dimension of connecting channel: The structural dimension of the assembly connection part between the opening and closing parts and the valve stem. 25. The flow area refers to the minimum cross-sectional area between the valve inlet end and the valve seat sealing surface (but does not refer to the "curtain" area). It is used to calculate the theoretical displacement without any resistance. 26. The flow diameter corresponds to the diameter of 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 refers to the change in outlet pressure caused by changes in the flow rate of the pressure reducing valve under stable flow conditions when the inlet pressure and other parameters remain unchanged. 29. General valve is a valve commonly used in pipelines in various industrial enterprises. 30. Automatic valve (Self-acting valve) relies on the ability of the medium (liquid, air, steam, etc.) to act on its own. 31. Actuated valve is a valve operated by manual, electric, hydraulic or pneumatic pressure.32. Hammer blow handwheel is a handwheel structure that uses impact force to reduce valve operating force. 33. Worm gear actuator is a device that uses a worm gear mechanism to open, close or adjust valves. 34. Pneumatic actuator is a driving device that uses air pressure to open, close or adjust valves. 35. Hydraulic actuator is a driving device that uses hydraulic pressure to open, close or adjust valves. 36. Hot condensate capacity (Hot condensate capacity) The larger amount of condensate that a trap can discharge under a given pressure difference and temperature 37. Steam loss (Steam loss) The amount of fresh steam leaked from the trap per unit time .

 

PART.2  Valve definition terms

 

 

 

 

 

 

1. Valve

 

A complete set of mechanical products with movable mechanisms used to control the flow of media in pipelines.

 

2. Gate valve, slide valve

 

The opening and closing parts (gate plates) are driven by the valve stem and move up and down along the valve seat (sealing surface).

 

3. Globe valve, stop valve

 

The opening and closing type (valve disc) is driven by the valve stem and moves up and down along the axis of the valve seat (sealing surface).

 

4.throttle valve

 

A valve that changes the cross-sectional area of ​​the passage through opening and closing parts (valve discs) to adjust flow and pressure.

 

5.Ball valve

 

Open-close (ball) valve that rotates around a curve perpendicular to the passage.

 

6.Butterfly valve

 

Open-close (butterfly plate) valve that rotates around a fixed axis.

 

7. Diaphragm valve

 

The opening and closing type (diaphragm) is driven by the valve stem, moves up and down along the axis of the valve stem, and separates the action mechanism from the medium.

 

8. Plug valve (cock)

 

A valve of the open-close type (plug) that rotates about its axis.

 

9. Check valve, non-return valve

 

The opening and closing type (valve disc) uses the force of the medium to automatically prevent the reverse flow of the medium.

 

10.Safety valve, relief valve

 

Open-close type (valve disc) is a valve that automatically opens and discharges when the pressure of the medium in the pipeline or machine equipment exceeds the specified value; it automatically closes when it is lower than the specified value to protect the pipeline or machine.

 

11.Pressure reducing valve

 

A valve that reduces the medium pressure by throttling the opening and closing parts (valve disc), and uses the direct effect of the pressure behind the valve to automatically maintain the pressure behind the valve within a certain range.

 

12. Steam trap

 

A valve that automatically drains condensation water and prevents steam leakage.

 

13. Draining Valves

 

Valves used for sewage discharge from boilers, pressure vessels and other equipment.

 

14. Low pressure valve

 

Various valves with nominal pressure PN≤1.6MPa.

 

15.Middle pressure valve

 

Various valves with nominal pressures ranging from PN≥2.0 to PN<10.0MPa.

 

16. high pressure valve

 

Various valves with nominal pressure PN≥10.0MPa.

 

17.Super high pressure valve

 

Various valves with nominal pressure PN≥100.0MPa.

 

18.High temperature valve

 

Used for various valves with medium temperature >450℃.

 

19.Sub-zero valve

 

Used for various valves with medium temperature ranging from -40℃ to -100℃.

 

20. Cryogenic valve

 

Used for various valves with medium temperature <-100℃.

 

 

PART. 3
Valve structure terminology

 

 

 

 

 

 

1. Structure length (face-to-face dimension, face-to-centre dimension)

The distance between the inlet and outlet end faces of the valve; or the distance from the inlet end face to the outlet axis.

2. Structural length of straight-through valve

(through way type of valves Face to face dimensions)

The distance between two planes perpendicular to the axis of the valve at the end of the valve body passage.

3. Structural length of angle valve

(angle type of valves Face to face,end to end, center to face and centerto end dimensions)

The distance between a plane perpendicular to the axis at one end of the valve body passage and the axis at the other end of the valve body.

4. Type of construction

The main characteristics of various types of valves in terms of structure and geometry.

5.Through way type

The valve body form has the inlet and outlet axes coincident or parallel to each other.

6.angle type

The valve body form has the inlet and outlet axes perpendicular to each other.

7.DC type (y-globe type, y-type, diaphragm type)

The valve body form has the passage in a straight line and the position of the valve stem and the axis of the valve body passage forming an acute angle.

8. Three way type

Valve body form with three passage directions.

9.T-pattern three way

The passage of the plug (or ball) is in the form of a "T" three-way.

10.L-pattern three way

The passage of the plug (or sphere) is in the shape of an "L" tee.

11.balance type

A structural form that utilizes medium pressure to balance its axial force on the valve stem.

12. Lever type

The structural form of the lever is used to drive the opening and closing parts.

13. Normally open type

When there is no external force, the opening and closing parts are automatically in the open position.

14.normally closed type

A structural form in which the opening and closing parts are automatically in the closed position when there is no external force.

15. Steam jacket type

Various valves with steam heating jacket structure.

16. Bellows seal type

Various valves with bellows construction.

17. Full-opening valve

A valve in which the inner diameter of the flow passage in all parts of the valve is the same as the nominal pipe inner diameter.

18.Reduced-opening valve

A valve with a reduced diameter of the flow passage hole in the valve.

19. Reduced-bore valve

The diameter of the flow channel hole in the valve is reduced, and the flow channel opening of the valve closing part is a non-circular valve.

20. One-way valve (un-directional valve)

Valves designed to seal in only one direction of media flow.

21. Bi-directional valve

The valve is designed to be sealed in both directions of media flow.

22.Double-seat two-way valve

(twin-seat, both seats bi-directional, valve)

The valve has two sealing seats, and each valve seat can be sealed in both media flow directions.

23. Double-seat valve with one-way seat and two-way seat

(twin-seat, one seat un-directional and one seatsbi-directional, valve)

For a valve with two sealing pairs, when in the closed position, the two sealing pairs can maintain the sealing state at the same time. The valve body in the middle cavity (between the two sealing pairs) has a port for releasing the medium pressure. Represents the symbol DBB.

24. Upper seal (back seat, back face)

A sealing structure that prevents medium from leaking from the stuffing box when the valve is fully open.

25. Pressure seal

A structure that uses medium pressure to realize automatic sealing at the connection between the valve body and the valve cover.

26. Dimension of valve stem head

Structural dimensions of the connection between the valve stem and the handwheel, handle or other mechanical control assembly.

27. Dimension of valve stem end

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

28. Dimension of connecting channel

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

29. Type of connection

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

 

 

PART. 4
Valve parts terminology

 

 

 

 

 

 

1.Body

Parts that are directly connected to pipelines (or machinery and equipment) and form the medium flow channel.

2. Bonnet, cover, cap, lid

The main part that is connected to the valve body and forms the pressure chamber with the valve body (or through other parts, such as diaphragms, etc.).

3. 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.

4. Valve disc (disc)

Opening and closing parts in globe valves, throttle valves, check valves and other valves.

5.阀座(bodyseat ring, shoulder seated, bottom seat)

It is installed on the valve body and forms a sealing pair with the opening and closing parts.

6.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.

7. Stem, apindle

The main parts that transmit the opening and closing force to the opening and closing parts.

8. Valve stem nut (yoke bushing, yoke nut)

Parts that form a kinematic pair with the valve stem thread.

9. Stuffing letter

The valve cover (or valve body) is filled with packing, a structure used to prevent the medium from leaking from the valve stem.

10. Stuffing box

Parts filled with packing to prevent medium from leaking from the valve stem.

11. Gland, gland flange, pne-piece glang

Parts used to compress the packing to achieve sealing.

12. Packing (packing, packing rings)

Packing stuffing that is put into the stuffing box (or stuffing box) to prevent leakage at the double stem of the medium.

13. Packing seat, packing washer

Parts that support the packing and keep the packing sealed.

14. Bracket (yoke)

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

15. Impact hand wheel

(impact handwheel, hammer blow handwheelimpact handwheel, hammer blow handwheel)

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