What type of control valve should be used for small-diameter two-position shut-off valves?
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For the safety interlocks in our production line, we need to use two-position cut-off valves with a small diameter, with no leakage allowed. We have tried using pneumatic ball valves, but the results were not satisfactory; the reason is that the medium flowing in our pipelines is coal tar, which has a high viscosity, and it is difficult for the normally closed valves to open. Is there a better option?
How about using a solenoid valve? Let’s hear what others think
It uses a plug valve, which features a simple structure, rapid on/off operation, ease of use, low fluid resistance, few components, and light weight. It is suitable for media with high viscosity and applications requiring rapid switching, but it is generally not suitable for steam and media at high temperatures.
Zero-leak butterfly valves are a good choice. What’s the caliber?
Butterfly valves are generally not used for small diameters; they are typically employed for larger diameters
In applications where zero leakage is required, ball valves are an excellent choice. If the valve cannot be opened, it is because the cylinder used is too small; if a single-acting cylinder is used, its diameter must be larger than that of a double-acting cylinder. The user can ask the manufacturer to recalculate and select an appropriate cylinder
Would V-ball valves or off-center rotary valves perform better, or should electric valves be used?
Did the second floor say to use a solenoid valve? ? ? Crazy, hehehe, there’s no other meaning behind it; it’s just a joke. Solenoid valves are definitely not meant for this purpose. In the chemical industry, they are rarely used to directly control fluid media, and the reason is that their flow capacity is too low. Secondly, the pressure tolerance of solenoid valves is very low, generally not exceeding 1 MPa. Thirdly, solenoid valves are only suitable for clean media, such as instrument air. How to use coal tar? It is recommended to use a plug valve. The advantages of plug valves are as mentioned on the 3rd floor. Additionally, plug valves feature a wedge-shaped seal; if the sealing performance deteriorates over time, it is possible to increase the sealing strength by pressing down further, which facilitates maintenance. Plug valves perform well in cutting off viscous media and fiber-containing media. Additionally, if imported valves are used, ball valves from OBIT should work well, but they are too expensive; a 2-inch manual valve costs around 100,000 RMB
A V-type ball valve can be used, but since the medium you are using is coal tar, the issue of heat tracing needs to be taken into consideration. Therefore, when selecting the valve, attention should be paid to its sealing material (I believe a polytetrafluoroethylene composite material should be used)