Brief Introduction of Vacuum Valve
Vacuum valve model composition:
The correct selection of the valve model and specifications requires understanding of the vacuum valve model; the company’s vacuum valve model preparation method is basically similar to ZBJ78016-89 “Vacuum valve model, preparation method”. The product model is composed of a basic model and an auxiliary model, separated by a short horizontal line, and the model composition is as follows:
Represents the range of vacuum used by the product, expressed by the first letter of the Chinese Pinyin keyword (printed capitals)
- The representative vacuum range is: low vacuum 105 ~ 10-1Pa (760 ~ 10 Torr)-D;
- The representative vacuum range is: high vacuum 105 ~ 10-4Pa (760 ~ 10-6 Torr) use-G;
- The representative vacuum range is: ultra-high vacuum 10 ~ 10-7Pa (760 ~ 10-9 Torr)-C;
Represents the valve plate structure or product function category, its first (or second) letter in Chinese Pinyin (printed capital) is used to indicate:
C flapper valve, Q inflation valve, D baffle valve, U ball valve, F flapper valve, W trimmer valve, I butterfly valve, Y differential pressure valve, M diaphragm valve;
Represents the product-driven method, which is expressed by the first letter of the Chinese Pinyin keyword (print capital):
S manual, D electric, Q pneumatic, C magnetic, Y hydraulic;
Represents the valve channel form, which is represented by the first letter of the Chinese Pinyin keyword (print capital):
Z direct valve, J angle valve, S three-way valve;
Special case: Only valves with inflation are coded with the capital letter Q in Chinese Pinyin, and other types of valves do not use symbols as codes.
Represents product specifications-nominal diameter, expressed in Arabic numerals, the unit is (mm):
For example: DN 16mm, 100mm, 500mm, etc. are expressed by 16,100,500, etc.
Special case: Very few products use Arabic numerals to indicate their performance parameters. For example, “30” in the model of GW-30-T type high vacuum trim valve indicates that the maximum adjustable amount of high vacuum trim valve is 30 Torr.L / S.
The corner note represents the seal structure of the shaft seal. At present, only the stainless steel bellows is used as the shaft seal.
Only some products (such as vacuum (pressure) ball valves) use uppercase English letters with parentheses to indicate the connection method or the code of the valve’s main seal and auxiliary material.
(KF) means the standard GB4982 “Clamping Vacuum Quick-release Flange”, (G) means the standard GB7306 “Cylinder Pipe Thread”, (F) means GB6070 “Loop Vacuum Flange” standard, (JB) means JB919-75 “Vacuum Flange” standard H or H (Ⅰ) indicates that the two ends of the valve adopt a welded structure, H (Ⅱ) indicates that one end of the valve adopts a welded structure, and the other end uses a plug structure with a rubber tube ;
Products designed by analogy several times Here are some examples:
- GM-25H (Ⅰ) high vacuum diaphragm valve, nominal diameter 25mm, welded structure at both ends.
- CCQ-150 pneumatic ultra-high vacuum plug-in valve with a nominal diameter of 150mm.
- GID-250 electric high vacuum butterfly valve, nominal diameter 250mm.
4, GUQ-40 (KF) pneumatic high vacuum (pressure) ball valve, nominal diameter 40mm, connection method is GB4982 “Clamping vacuum quick release flange” DN40 quick release flange.
5, GD-J100b high vacuum baffle valve, nominal diameter 100mm, the conduction form is angle type, the shaft seal form is stainless steel metal bellows.
6, DYC-JQ50 electromagnetic vacuum differential pressure valve, nominal diameter 50mm, the conduction form is angle type. (Low vacuum generally only needs the word vacuum).
7, DDC-JQ80 electromagnetic vacuum belt inflation valve, nominal diameter 80mm, the conduction form is angle type. (Low vacuum generally only needs the word vacuum).
8, GDC-J25b electromagnetic high vacuum baffle valve, nominal diameter 25mm, the conduction form is angle type. The shaft seal is made of stainless steel metal bellows.
The vacuum valve has the following characteristics:
The pressure is lower than atmospheric pressure, and the pressure drop on the disc must not exceed 1 kgf / cm2. The operating temperature of the medium depends on the process in which the device is used. The temperature generally does not exceed the range of -70 ~ + 150 ° C.
The most basic requirements for this type of valve are to ensure a high degree of tightness in the connection and the tightness of the structure and gasket material.
Vacuum valves can be divided into four groups according to media pressure:
1) Low vacuum valve: medium pressure p = 760 ~ 1 mmHg.
2) Medium vacuum valve: p = 1 × 10-3 mm Hg.
3) High vacuum valve: p = 1 × 10-4 ~ 1 × 10-7 mm Hg.
4) Ultra-high vacuum valve: p≤1 × 10-8 mm Hg.
As a closed-circuit valve with a diameter less than 250 mm, the widely used valve bellows has a linear motion vacuum bellows globe valve. Gate valves are subject to greater restrictions, but this is mainly for large bores. Also available are ball stopcocks (ball valves), plunger valves and butterfly valves. Plug valves for vacuum valves have not been promoted, because the plug valves need to be lubricated with oil, so that oil vapor may enter the vacuum system, which is not allowed. Vacuum valves can be controlled manually and remotely on the spot, as well as electric, electromagnetic drive (solenoid valve), pneumatic and hydraulic controls.