Cryogenic valves are valves that can be used under low temperature conditions. Valves that operate below -40°C are commonly referred to as cryogenic valves. Cryogenic valves are one of the indispensable important equipments for petrochemicals, air separation, natural gas and other industries. Their quality determines whether they can produce safely, economically, and continuously. With the development of modern science and technology, the use of cryogenic valves has become more and more extensive, and the demand is also increasing.
For temperatures above -50 °C, long neck structures are generally not used. For ball valves with temperatures below -50 °C, the neck length T is determined according to the design and calculations of Yijie Valve Company. The cryogenic ball valve is mainly used to output liquid cryogenic media such as Ethylene, liquid oxygen, liquid hydrogen, liquefied natural gas, liquefied petroleum products, etc. are not only flammable and explosive, but also have to be gasified when they are heated. When they are gasified, the volume expands hundreds of times.
The material of the LNG valve is very important, and the material is unqualified, which can cause external leakage or internal leakage of the housing and the sealing surface. The comprehensive mechanical properties, strength and rigidity of the component can not meet the requirements of use or even fracture. Leakage of liquefied natural gas caused explosions. Therefore, in the process of developing, designing, and developing liquefied natural gas valves, material is the most important issue. Valve body, valve cover: LCB (-46 °C), LC3 (-101 °C), CF8 (304) (-196 °C).
The cryogenic valve requires the use of a long-neck bonnet structure, which reduces the amount of heat introduced into the external device; ensures that the temperature of the stuffing box is above 0° C. so that the packing can work normally; and it prevents the stuffing box from being overly cold. The valve stem in the stuffing box and the parts in the upper part of the valve cover are frosted or frozen.
The design of the long-neck bonnet cover is mainly the design of the length L of the neck. L refers to the distance from the bottom of the stuffing box to the upper surface of the upper seal seat. It is related to the thermal conductivity of the material, the thermal conductivity area, the surface heat dissipation coefficient and the heat dissipation area. The calculation is relatively complicated and generally obtained by experimental methods.
The working conditions of cryogenic valves are harsh. Most of their working media are flammable, explosive, and highly permeable. The minimum operating temperature is -269°C and the maximum operating pressure is 10 MPa. Therefore, the design, manufacture and inspection of cryogenic valves are quite different from those of general valves.
Yijie Valve has always been inspirational to do everything. We encountered many customers in the sales misunderstanding of the low-temperature valve will think of writing a mid-section. A lot of guests, directly put the valve material is low-temperature steel is directly considered a cryogenic valve, in fact, it is only a semi-finished product of cryogenic valves, because he did not pass the cryogenic cryogenic treatment, it can be said cryogenic cryogenic treatment is the crowning touch of cryogenic valves The key to cryogenic valves is cryogenic treatment, so as to ensure that the various parameters of cryogenic valves meet the requirements, especially the expansion coefficient, will not lead to various valve stuck conditions in use. Sometimes considering the issue of price, we must also consider the quality of the valve. Cryogenic valves are special valves.
The realization of most of the domestic cryogenic valves are not cryogenic cryogenic treatment, the first cost will be expensive, here I can give you a rough calculation, if the cost of their own jacketed cryogenic equipment is high, the cryogenic equipment is expensive, also In addition to the cryogenic liquid nitrogen, which is a necessary material, it is also a poorly stored medium. There is also a lot of liquid nitrogen consumed in handling a valve, and the price of liquid nitrogen is not cheap. Our factory manufactures low-temperature valves with special low-temperature treatment, places the rough-processed parts in the cooling medium for several hours (2-8 hours) to release stress, ensure the low-temperature performance of the materials, and guarantee the precision machining dimensions. When the valve is in a low temperature condition, it causes leakage due to a temperature change.
Cryogenic valve inquiry enough attention to the matter is now:
In order to better meet the customer's requirements for use in cryogenic valves, if you need cryogenic valves, please provide the specific parameters you know
1. The name of the cryogenic media
2. Low temperature medium temperature
3. You need to customize the length of the long neck of your cryogenic valve, which is not provided according to our standard
4. Cryogenic valve material (can be customized according to customer requirements)
5. Cryogenic valve pressure
6. Cryogenic valve seals (soft or hard seals)
7. Connection method (flange connection or welding)
8. Drive method (manual, pneumatic, electric)
9. Delivery date