How to select a ball valve
What factors need to be considered when choosing a valve
1 Clarify the purpose of the valve in the equipment or device
Determine the working conditions of the valve: the nature of the applicable medium, working pressure, working temperature and control mode.
2 Select the correct valve type
The correct choice of valve type is based on the designer's full grasp of the entire production process and operating conditions as a prerequisite, in the selection of valve type, the designer should first master the structural characteristics and performance of each valve.
3 Determine the end connection of the valve
In threaded connections, flange connections, and welded end connections, the first two are most commonly used. Threaded valves are mainly valves with nominal diameter below 50mm, if the diameter size is too large, the installation and sealing of the connection part is very difficult. Flange connected valve, its installation and disassembly are more convenient, but the more threaded connected valve is bulky, the price is higher, so it is suitable for a variety of diameter and pressure of the pipeline connection. The welded connection is suitable for higher load cutting conditions and is more reliable than the flange connection. However, the disassembly and reinstallation of welded valves are more difficult, so its use is limited to occasions where it can usually operate reliably for a long time, or where the conditions of use are engravings and the temperature is higher.
4. Selection of valve material
The selection of valve shell, inner parts and sealing surface material, in addition to considering the physical properties of the working medium (temperature, pressure) and chemical properties (corrosion), should also master the cleanliness of the medium (there are no solid particles), in addition, but also refer to the relevant provisions of the state and the use of the department. The correct and reasonable selection of valve material can obtain the most economical service life and the best performance of the valve. The selection sequence of valve body materials is: cast iron - carbon steel - stainless steel, and the selection sequence of sealing ring materials is: rubber - copper - alloy steel -F4.
5 Others
In addition, the flow rate and pressure level of the fluid flowing through the valve should be determined, and the appropriate valve should be selected using the available information (such as the valve product catalog, valve product samples, etc.).
How to select ball valve
Ball valve is suitable for low temperature, high pressure, high viscosity media. Most ball valves can be used in media with suspended solid particles, and can also be used in powdery and granular media according to the material requirements of sealing; The full-channel ball valve is not suitable for flow regulation, but it is suitable for occasions requiring quick opening and closing, which is easy to achieve emergency cutting; Ball valves are usually recommended in pipelines with strict sealing performance, wear, shrinking channels, rapid opening and closing action, high pressure cutoff (large pressure difference), low noise, gasification, small operating torque, and small fluid resistance.
Ball valve is suitable for light structure, low pressure cut-off, corrosive media; Ball valve or low temperature, cryogenic medium of the most ideal valve, low temperature medium piping system and device, should be selected with a low temperature ball valve cover; When the floating ball valve is selected, the valve seat material should undertake the load of the ball and the working medium. The large-diameter ball valve needs a larger force during operation. The ball valve with DN≥200mm should use worm gear transmission form. Fixed ball valve is suitable for large diameter and high pressure occasions; In addition, the ball valve used for the process of highly toxic materials and combustible media pipelines should have a fireproof and anti-static structure.