Valves, as important equipment for controlling the flow of media in pipelines, have a series of professional terms to describe their performance, structure, function, and classification. The following is a detailed analysis of valve professional terminology:

1、 Basic Definition and Classification

Valve:

Definition: The overall mechanical product with a movable mechanism used to control the flow of media in pipelines.

Function: Open and close pipelines, control flow direction, regulate and control parameters of the conveying medium (temperature, pressure, and flow rate).

Type:

Classified by purpose or main structural characteristics, such as gate valves, globe valves, throttle valves, ball valves, butterfly valves, diaphragm valves, plug valves, check valves, safety valves, pressure reducing valves, etc.

2、 Performance parameters

Strength performance:

Definition: The ability of a valve to withstand medium pressure.

Importance: Valves are mechanical products that withstand internal pressure and must have sufficient strength and stiffness to ensure long-term use without rupture or deformation.

Sealing performance:

Definition: The ability of each sealing part of a valve to prevent medium leakage.

Sealing part: the contact area between the opening and closing parts and the sealing surface of the valve seat; The matching of packing with valve stem and packing box; The connection between the valve body and the valve cover.

Leakage types: internal leakage (affecting the ability to cut off the medium) and external leakage (causing material loss, environmental pollution, and even accidents).

Flowing medium:

Definition: After the medium flows through the valve, there will be a pressure loss (pressure difference before and after the valve), that is, the valve has a certain resistance to the flow of the medium.

Importance: From the perspective of energy conservation, valves should be designed and manufactured to minimize their resistance to flowing media.

Opening and closing force and torque:

Definition: The force or torque required to open or close a valve.

Influencing factors: When closing the valve, it is necessary to establish a certain sealing pressure between the opening and closing parts and the sealing surface of the valve seat, and overcome the frictional forces between the valve stem and packing, valve stem and nut, and other friction parts.

Opening and closing speed:

Definition: The time required for a valve to complete one opening or closing action.

Importance: Generally, there are no strict requirements for the opening and closing speed of valves, but some operating conditions have special requirements for the opening and closing speed.

Action sensitivity and reliability:

Definition: The sensitivity of a valve to changes in medium parameters.

Importance: For valves with specific functions such as throttle valves, pressure reducing valves, and regulating valves, their functional sensitivity and reliability are very important technical performance indicators.

service life:

Definition: The durability of a valve.

Representation method: It is usually expressed in terms of the number of opening and closing times that can ensure the sealing requirements, or it can be expressed in terms of usage time.

3、 Structure and components

Discs:

Definition: A general term for a component used to cut off or regulate the flow of a medium, such as the gate plate in a gate valve or the valve disc in a throttle valve.

Packing:

Definition: A filling material placed in a stuffing box (or stuffing box) to prevent medium leakage from the valve stem.

Packing Seat:

Definition: A component that supports packing and maintains packing sealing.

Packing gland:

Definition: A component used to compress packing to achieve sealing.

Yoke bracket:

Definition: A component used to support the valve stem nut and transmission mechanism on the valve cover or body.

Dimension of Connecting Channel:

Definition: The structural dimensions of the connection between the opening and closing components and the valve stem assembly.

Flow Area and Flow Diameter:

Definition: Refers to the minimum cross-sectional area and corresponding diameter between the inlet end of the valve and the sealing surface of the valve seat, used to calculate the theoretical displacement without any resistance effect.

4、 Testing and Standards

Seal Test:

Definition: Test for inspecting the sealing performance of opening and closing components and valve bodies.

Back Seal Test:

Definition: Test to verify the sealing performance of the valve stem and valve cover sealing pair.

Seal Test Pressure:

Definition: The pressure specified during the sealing test of a valve.

Suitable Medium and Suitable Temperature:

Definition: The medium and temperature range that the valve can be applied to.

5、 Other terms

Face to Face Dimension: The distance between the inlet and outlet faces of a valve, or the distance from the inlet face to the outlet axis.