The test medium to the specified value is introduced from the end of the import and the other end is closed to see that the valve and valve cap are not leak-free. The sealing test introduces the test medium from the end of the export and inspects the sealing surface at the end of the import, with no leakage in fillings and gaskets. Test pressure reduction valve method
The test method is to gradually adjust the valve's calibration bolts after the import pressure has been adjusted so that the export pressure changes in a sensitive and continuous manner within the maximum and minimum values, without any stagnation or obstruction。
1. The inscription is fixed on the valve or wheel. The marked data are complete and reflect the basic characteristics of the valve. According to the production plant on the label, the valve is obtained from the production plant on the basis of damageable drawings and information, with reference to the repair according to the date of departure. Based on the conditions of use provided on the signboard, the material and form for the replacement of the gasket, the root and the material for the replacement of the other valves are marked by casting, printing, etc., indicating the flow of the valves to the valves by public pressure, working pressure, common calibre and medium. There is also a sign on the valve - the open-scale indicator, which has an open scale line or an open arrow etc. The upper end of the throttle, the dark rod valve, is marked with an open indicator indicating the direction of the closure with an arrow pointed on the wheel. A straight groove is carved on the end of the valve to be opened in line with the valve channel, which is closed at 90°。
2 gate shape: closed pieces move along the central line vertically in the valve。
The structure of the diaphragm valve, which differs significantly from that of the general valve, is a new type of valve and a special form of cut-off valve, with the release of a diaphragm made of soft materials that separates the internal cavity of the valve from the inner cavity of the valve and the driving parts and is widely used in various fields. Common diaphragm valves include liner diaphragm valves, fluorine diaphragm valves, unlined membrane valves and plastic diaphragm valves. The diaphragm valves contain a scratching diaphragm or a combination of diaphragms in the valves and caps, and the closures are a compression device connected to the diaphragm. Valves can be stylisted or pipe walls that flow directly. The advantage of diaphragm valves is that they operate in isolation from media access, which not only ensures the purity of the work medium but also prevents the possibility of piped intermediates impacting the parts that manipulate the work of the body. In addition, any form of individual sealing is not required at valves unless used as a safety facility in the control of harmful media. In diaphragm valves, since only diaphragms and valves are exposed to work media, both of which can use a variety of materials, the valve can ideally control multiple work media, especially those with chemical corrosive or suspended particles. The working temperature of the diaphragm valve is usually limited by the material used in the diaphragm and valve liner, and its working temperature range is approximately -50 ~175 °c. The diaphragm valve is simple and consists of only three main components of the valve, the membrane and the valve combination. The valve is easily disassembled and repaired quickly, and replacement of the diaphragm can be done on site and in a short period of time。
Air-sealed tests shall be conducted at a working pressure of 1. 25 times for the rotor valve used for gas。
Recommended to read the image of the aerodynamic dust fowler
The aerodynamic valve working principle is applied in situations requiring rapid release, generally not in the case of a vapour and higher temperature media, in the case of a lower temperature and a much viscous medium, but also in the case of a medium with suspended particles. The choice of a butterfly valve indicates that the butterfly valve is applied to larger calibres (e. G., dn>600mm) and to shorter structural length requirements, as well as to high-speed flow regulation and release requirements, generally for water, oil and compressed air media such as temperature ≤80°c, pressure ≤1. 0 mpa, and, because of the greater loss of pressure of the butterfly valve vis-à-vis the valve and ball valve pressure, the butterfly valve is applied to less demanding piped systems。
4 high pressure valves: valves known as 100-800 kg/cm2 of public pressure。
The pneumatic valves can be configured with a large calibre relative to the manual and turbo-turned ball valves (both manual and turbo-turned valves are generally below the dn300 calibre, which can now reach the dn1200 calibre). The balloon valves have been widely used in sectors such as oil, chemicals, power generation, paper, atomic energy, aviation and rockets, as well as in people's daily lives. Bulk valves divided by structure:
They have heat, acid, alkalin, corrosive, grinding, oil-resistant, etc。
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