Electric valve manufacturers of the valve connection forms are mainly flange, thread, ferrule, clamp, internal self-tightening, welding, clamping, etc., respectively, for different occasions, the following we are introduced in detail.
1, flange connection This is the connection form used in the valve Z more. According to the shape of the bonding surface can be divided into the following categories.
(1) smooth type: used for valves with low pressure. Processing is more convenient
(2) convex: higher working pressure, can use hard gaskets
(3) tongue and groove: available plastic deformation of the gasket, more widely used in corrosive media, the sealing effect is better.
Electric valve manufacturers
(4) trapezoidal groove type: with oval metal ring for the gasket, used in the working pressure ≥ 64 kg / cm2 valve, or high-temperature valve. (5) lens type: gasket is lens-shaped, made of metal. Used for working pressure ≥ 100 kg / cm2 of high-pressure valves, or high-temperature valves.
(6) O-ring type: This is a newer form of flange connection, which is developed with the emergence of various rubber O-ring, which is more reliable than the general flat gasket in sealing effect.
2, threaded connection This is a simple connection method, commonly used in small valves. And divided into two cases.
(1) direct sealing: the internal and external threads act directly as a seal. In order to ensure that the connection does not leak, often filled with lead oil, thread hemp and PTFE raw material tape; which PTFE raw material tape, the use of increasingly widespread; this material corrosion resistance is very good, excellent sealing effect, easy to use and save, disassembly, can be removed intact, because it is a non-stick film, much superior to lead oil, thread hemp. 2) indirect sealing: thread tightening force, transfer to the two planes between the gasket, so that the gasket to play a sealing role.
3, ferrule connection ferrule connection, developed in China in recent years, its connection and sealing principle is that when tightening the nut, the ferrule is under pressure, so that its edge bite into the outer wall of the tube, the outer cone of the ferrule and under pressure with the joint body cone, and thus can reliably prevent leakage. The advantages of this connection form are.
1) Small size, light weight, simple structure, easy disassembly and assembly;
(2) Strong connection force, wide range of use, can withstand high pressure (1000 kg/cm2), high temperature (650°C) and shock vibration;
3) A variety of materials can be used, suitable for corrosion prevention;
4) Processing accuracy is not required;
5) Easy to install at height. At present, the ferrule connection form, has been used in some small-diameter valve products in China.
4, clamp connection This is a quick connection method, which requires only two bolts, suitable for frequent disassembly of low-pressure valves.
5, the internal self-tightening connection The above various forms of connection, are the use of external forces to offset the medium pressure to achieve sealing. The following introduces the use of medium pressure for self-tightening connection form. It is installed at the inner cone seal ring, and the media side of a certain angle, the media pressure to the inner cone, and then to the seal ring, in a certain angle of the cone, resulting in two forces, one parallel to the centerline of the valve body outward, the other pressure to the inner wall of the valve body. This latter force is the self-tightening force. The greater the medium pressure, the greater the self-tightening force. Therefore, this type of connection is suitable for high pressure valves. It saves a lot of material and labor than the flange connection, but also needs a certain amount of preload in order to use reliably when the pressure inside the valve is not high. The valve made by using the principle of self-tight seal is generally a high pressure valve.
6、Welding
(1) Butt welding: for higher pressure applications.
(2) socket welding: for low pressure service.
7、Clipping Generally used for low pressure service, such as butterfly valve connection.
8, there are many forms of valve connections, such as non-metallic valves, socket connections, fusion connections, etc., valve users should be treated according to the specific situation with Hugh.
