What are the common problems encountered with bellows control valves in polysilicon production?
Thread Content
Since bellows control valves are used in toxic environments, what issues should be taken into consideration during actual use? How do brands such as Fisher, Samson, and Motoyama handle the manufacturing, securing, and prevention of torsion in bellows?
First, check whether the compressed air supply is unobstructed. Verify that the opening degree at the site matches the value indicated by the computer. When in use, avoid full opening or full closing; instead, adjust it gradually
Bellows control valves are primarily used with toxic, harmful, and flammable media; the bellows serve to isolate the medium from the valve stem and prevent leaks. Every bellows valve has a specific purpose for use, and if its service life is exceeded it is prone to breaking, which leads to failure of the sealing mechanism. Additionally, the medium should be clean, as otherwise it may get stuck in the grooves within the bellows, reducing its lifespan. The material choice is also important – for handling chlorine, Hastelloy is the best option. Moreover, bellows valves should have multiple layers; those with only one layer are too thin and have a shorter lifespan
On polysilicon production lines, the process media used with bellows control valves are mainly SIHCl3, Sicl4, HCl, as well as hydrogen containing these substances. A common problem is the rupture of the bellows, leading to leaks; at first the leakage is minor, but if not addressed promptly it worsens, and it becomes necessary to have the manufacturer replace the bellows. Sometimes, it happens that the length of the bellows is too great, which causes the valve to fail to operate frequently
On polysilicon production lines, the process media used with bellows control valves are mainly SIHCl3, Sicl4, HCl, as well as hydrogen containing these substances. A common problem is the rupture of the bellows, leading to leaks; at first the leakage is minor, but if not addressed promptly it worsens, and it becomes necessary to have the manufacturer replace the bellows. Sometimes, it happens that the length of the bellows is too great, which causes the valve to fail to operate frequently