The main factors that should be considered when designing butterfly valves are:

1. Process conditions of the process system where the valve is located

Before designing, you must first fully understand the process conditions of the process system where the valve is located, including: medium type (gas, liquid, solid phase and two-phase or multi-phase mixture, etc.), medium temperature, medium pressure, medium flow (or flow rate), power source and its parameters, etc.

1) Media type

The butterfly valve structure is usually designed according to the primary medium, but auxiliary media, such as those used for cleaning, testing and purging, must also be considered. The adhesion and deposition of the medium have an impact on the valve structural design; at the same time, more attention should be paid to the impact of the corrosiveness of the medium on the structure and materials.

2) Medium temperature

Possible problems include: ① Different thermal expansion: Different temperature gradients or expansion coefficients will cause uneven expansion of the valve sealing pair, causing the valve to become stuck or leak when opening and closing. ② Changes in material properties: The reduction in allowable stress of materials at high temperatures must be considered during design. In addition, thermal cycling can sometimes cause dimensional changes as parts that expand at very high temperatures may yield locally. ③Thermal stress and thermal shock.

3) Medium pressure

It mainly affects the strength and stiffness design of the pressure-bearing parts of the butterfly valve, as well as the design of the necessary specific pressure and allowable specific pressure of the sealing pair.

4) Medium flow

It mainly affects the erosion resistance of the butterfly valve channel and sealing surface, especially for gas-solid and liquid-solid two-phase flow media, which must be carefully considered.

5) Power supply

Its parameters directly affect the connection interface design, opening and closing time, drive sensitivity and reliability of the butterfly valve. Changes in power supply voltage and current intensity have little effect on the valve. Mainly, the pressure and flow of the air source and hydraulic source will directly affect the realization of the butterfly valve function.

2. Butterfly valve function

When designing, it must be clear whether the butterfly valve is used to connect or cut off the medium in the pipeline, or to regulate and control the flow and pressure of the medium in the pipeline. The factors considered in the design of the sealing pair of control valves with different functions are different. If the valve is used to connect or cut off the medium in the pipeline, the cutoff capacity of the valve, that is, the sealing performance of the valve, is important to ensure that the selected Under the premise that the material must be corrosion-resistant, low, medium pressure and normal temperature valves often adopt a soft-sealing structure, while medium, high-temperature and high-pressure regulating valves use a hard-sealing structure; if the valve is used to regulate and control the medium in the pipeline When considering the flow rate and pressure, the inherent regulating characteristics and regulating ratio of the valve are mainly considered.