The reason and solution for the low temperature ball valve to get stuck easily
Low temperature valve, low temperature stop valve, low temperature ball valve, low temperature shut-off valve are installed at normal temperature, work at low temperature, and the temperature varies widely. If it is improperly designed or installed, it is easy to generate thermal stress or deformation. At the same time, the operating part of the valve is at normal temperature and the circulating part is at a low temperature. In order to reduce the cold damage, the valve stem tends to be made long, and it is easy to deform and get stuck. In this regard, what are the main reasons for the valve to get stuck at low temperatures? 
1. During installation, the valve and pipe are unreasonably configured to produce pre-stress; or the pipe has poor cold compensation capability, and the valve position changes at low temperature; or the valve lacks a bracket to deform at low temperature; or the valve is improperly fixed, and the cold box is deformed at low temperature. It affects the concentricity of the valve stem and the valve body.
2. In design, due to the different material of the valve stem and the valve sleeve, the coefficient of linear expansion is different. Generally, the valve stem is made of stainless steel, the coefficient of linear expansion is 1.73×10-6°C-1; the valve sleeve is brass, and the coefficient of linear expansion is 19.9×10-6°C-1, that is, the shrinkage of brass is larger than that of stainless steel, and it may be at low temperature. Bit the thread. In particular, when a dark rod structure and a fine thread are used, the temperature of the thread has a large variation range, and the thread gap is small, which is more likely to cause a bite.
3. During operation, due to incomplete heating at the valve, or water in the valve packing, freezing at low temperature, or closing the valve too tight at normal temperature, causing the thread to bite. 
In order to prevent the phenomenon of valve jamming, it is advisable to use a bright rod structure and a thick trapezoidal thread in the design; there should be a solid bracket at the valve to prevent the valve from being bent along with the pipe. The valve and the cold box can be fixed by elastic connection to prevent the valve stem from being deformed and not concentric with the valve body. During the bare cold period, the valve installation condition should be checked and adjusted in the cold state. When the valve is found to be stuck after cooling, The fixed flange of the valve on the cylinder can be adjusted to make it switch freely. In the operation, the heating before starting should be thorough, and the principle of not leaking when closing the valve should not be used too much.
2. In design, due to the different material of the valve stem and the valve sleeve, the coefficient of linear expansion is different. Generally, the valve stem is made of stainless steel, the coefficient of linear expansion is 1.73×10-6°C-1; the valve sleeve is brass, and the coefficient of linear expansion is 19.9×10-6°C-1, that is, the shrinkage of brass is larger than that of stainless steel, and it may be at low temperature. Bit the thread. In particular, when a dark rod structure and a fine thread are used, the temperature of the thread has a large variation range, and the thread gap is small, which is more likely to cause a bite.
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