Valves are important components of industrial pipeline systems and play a crucial role in the production process.

1、 Main functions of valves

1) Connecting and cutting off media: Gate valves, butterfly valves, and ball valves can be selected;

2) Prevent medium backflow: check valve can be selected;

3) Adjust medium pressure and flow rate: optional shut-off valve and regulating valve;

4) Separation, mixing, or distribution of media: Plug valves, gate valves, and regulating valves can be selected;

5) To prevent the medium pressure from exceeding the specified value and ensure the safe operation of pipelines or equipment, safety valves can be selected.

The selection of valves is mainly considered from two aspects: device operation and economy.

2、 Principles for selecting valves

Multiple key factors are involved, and the following is a detailed discussion on these factors:

1. Properties of the fluid being transported

Fluid type: Whether the fluid is liquid, gas, or vapor directly affects the choice of valve. For example, liquids may require shut-off valves, while gases may be more suitable for ball valves. Corrosive: Corrosive fluids require corrosion-resistant materials such as stainless steel or special alloys. Viscosity: High viscosity fluids may require larger diameters or specially designed valves to reduce clogging. Particle content: Fluids containing solid particles may require wear-resistant materials or specially designed valves, such as pinch valves.

2. Function of valves

Switch control: In situations where only switch function is required, ball valves or gate valves are common choices.

Flow regulation: When precise flow control is required, globe valves or regulating valves are more suitable.

Prevent backflow: Check valves are used to prevent fluid backflow.

Diverting or merging: Three way valves or multi way valves are used for diverting or merging.

3. Valve size

Pipeline size: The valve size should match the pipeline size to ensure smooth fluid flow. Flow requirements: The valve size must meet the system flow requirements, as being too large or too small can affect efficiency. Installation space: Installation space limitations may affect the selection of valve size.

4. Valve resistance loss

Pressure drop: Valves should minimize pressure drop as much as possible to avoid affecting system efficiency.

Flow channel design: Full bore valves (such as full bore ball valves) can reduce resistance losses.

Valve type: Some valves (such as butterfly valves) have low resistance when opened, making them suitable for low pressure drop situations.

5. The working temperature and pressure of the valve

Temperature range: Valve materials need to adapt to fluid temperature, and temperature resistant materials should be selected for high or low temperature environments.

Pressure rating: Valves should be able to withstand the maximum working pressure of the system, and high-pressure systems should choose valves with high pressure ratings.

Comprehensive influence of temperature and pressure: Special consideration should be given to material strength and sealing performance in high temperature and high pressure environments.

6. Material of valve

Corrosion resistance: Select appropriate materials based on the corrosiveness of the fluid, such as stainless steel, Hastelloy, etc.

Mechanical strength: Valve materials need to have sufficient mechanical strength to withstand working pressure.

Temperature adaptability: Materials need to adapt to working temperatures, heat-resistant materials are required for high temperature environments, and cold resistant materials are required for low temperature environments.

Economy: Choose materials with good economy while meeting performance requirements.