Low-temperature valves are valves used in low-temperature medium conditions. They are mostly used in devices for low-temperature media such as ethylene, liquefied natural gas, etc., LNG storage tanks, air separation equipment, etc. The working conditions of low-temperature valves are very demanding. The working medium of most of them is flammable and explosive substances like ethylene, LNG, LOX, etc. When heated, they vaporize and expand hundreds of times, with the lowest working temperature reaching -196℃ and the maximum operating pressure reaching 10 MPa. Therefore, the design, manufacture, and inspection of low-temperature valves differ significantly from those of general valves. Our company has accumulated rich experience through years of production practice. From design, process to manufacturing, it has become increasingly mature, and we have developed a series of low-temperature valve products.
Product Characteristics
Valve body structure: There are two types of valve bodies: split side-mounted type and top-mounted type. The top-mounted type can be maintained online.
Sealing form: The low-temperature ball valve has two sealing forms: metal sealing and soft sealing. The metal sealing ball surface and the valve seat sealing surface are coated with nickel-based hard alloy, while the soft sealing valve seat is made of PCTFE material.
Valve bonnet extension structure: To prevent the elasticity of the packing from decreasing and freezing at low temperatures, an extended neck valve bonnet is used, raising the position of the packing.
Valve bonnet cavity discharge function: A T-shaped hole is drilled at the lower part of the valve stem to connect the valve bonnet cavity with the middle cavity of the valve body, discharging the pressure in the valve cover cavity and preventing overpressure.
Pressure relief function of the middle chamber: A single-direction sealing valve seat is adopted at the inlet end, and a double-direction sealing valve seat is used at the outlet end. The valve seat at the inlet end has a self-pressure relief function. If the medium in the middle chamber heats up and vaporizes, and abnormal pressure rise occurs, it can automatically relieve pressure to the upstream. Also, according to requirements, a pressure relief hole can be drilled at the center of the ball body inlet end to allow the pressure in the middle chamber to be relieved to the upstream.
Elastic element loaded valve seat: The valve seat is pre-tightened by a spring (or butterfly spring), featuring self-tightening properties and low-temperature sealing compensation functions.
Valve body sealing: A combination of metal wound gaskets and plug seals is used for sealing between the valve bodies, ensuring the sealing performance at low temperatures.
Radial sealing of the valve seat: It adopts UPE + ELgiloy material plug seal (energy storage ring) for sealing.
Valve stem seal: Utilizes UPE + ELgiloy material plug seal (energy storage ring) + flexible graphite packing seal
The pressure-bearing components and valve internals of the low-temperature ball valve are all made of austenitic stainless steel, and undergo a deep cold treatment for more than two hours.
Three protection functions: fire prevention, anti-static, valve stem anti-slip out.
