How the entire valve is connected to the pipeline or equipment is a problem that cannot be ignored, because most of the valve's running, emitting, dripping, and leaking phenomena occur here. 1 flange connection Flange connection is the most used connection form between valve and pipeline or equipment. It refers to a detachable connection that is connected to each other by flanges, gaskets and bolts as a set of combined sealing structure. Pipe flange refers to the flange used for piping in the pipeline installation, and refers to the inlet and outlet flanges of the equipment when used on the equipment. The flange connection is easy to use and can withstand greater pressure. Flange connection can be applied to valves of various nominal sizes and nominal pressures, but there are certain restrictions on the operating temperature. In high temperature conditions, the flange connecting bolts are prone to creep and cause leakage. In general, the method The blue connection is recommended to be used at a temperature of ≤350℃. According to the shape of the joint surface, it can be divided into the following types: Smooth: used for valves with low pressure. Processing is more convenient Concave-convex type: high working pressure, medium hard washer can be used Tongue and groove type: gaskets with greater plastic deformation can be used, which are widely used in corrosive media and have better sealing effects Trapezoidal groove type: oval metal ring is used as a gasket, used for valves with working pressure ≥60kg/cm² or high temperature valves Lens type: The washer is a lens shape and is made of metal. For high-pressure valves or high-temperature valves with working pressure ≥100 kg/cm² O-ring type: a newer flange connection, the sealing effect is more reliable than ordinary flat gaskets 2 pair clip connection A connection form in which the valve and two pipes are directly clamped together with bolts. 3 Welding connection Welding connection refers to a connection form in which the valve body has a welding groove and is connected to the piping system by welding. Standards such as GB/T 12224, API600, ASME B 16.34 and so on make provisions for welding grooves. The welding connection between the valve and the pipeline is divided into butt welding connection (BW) and socket welding connection (SW), and the socket welding end should meet the requirements of JB/T 1751. Butt welding connection (BW) can be applied to various sizes, pressures and high temperature working conditions, socket welding connection (SW) is generally suitable for valves ≤DN50. 4 threaded connection This is a simple connection method, often used for small valves. There are two situations: Direct sealing: the internal and external threads directly play a sealing role. In order to ensure that the joints are not leaking, they are often filled with lead oil, thread hemp and PTFE tape. Among them, PTFE tape is widely used. This material has good corrosion resistance, excellent sealing effect, convenient use and storage, and can be completely removed when disassembled, because it is a non-sticky film, which is much better than lead oil and hemp. Indirect sealing: The tightening force of the thread is transmitted to the gasket on the two planes, so that the gasket plays a sealing role. 5 card set connection The working principle of the ferrule connection is that when the nut is tightened, the ferrule is under pressure so that its blade bites into the outer wall of the pipe, and the outer cone of the ferrule is tightly sealed with the inner cone of the joint under pressure, thus reliably preventing 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, resistant to high pressure (1000 kg/cm²), high temperature (650°C) and shock and vibration; 3) There are many options This kind of material is suitable for anti-corrosion; 4) The processing accuracy is not high; 5) It is convenient for high-altitude installation. At present, the ferrule connection form has been adopted in some small-caliber valve products in my country. 6 clamp connection This is a quick connection method. It only requires two bolts and is suitable for low-pressure valves that are frequently disassembled. 7 internal self-tightening connection Internal self-tightening connection is a connection form that uses medium pressure for self-tightening. Its sealing ring is installed at the inner cone and is at a certain angle with the side facing the medium. The pressure of the medium is transmitted to the inner cone and then to the sealing ring. On the cone with a certain angle, two component forces are generated, one with The center line of the valve body is parallel to the outside, and the other is pressed against the inner wall of the valve body. The latter component is the self-tightening force. The greater the medium pressure, the greater the self-tightening force. Therefore, this connection form is suitable for high-pressure valves. Compared with flange connection, it saves a lot of material and manpower, but it also needs a certain pre-tightening force to be reliable when the pressure in the valve is not high. Valves made with the principle of self-tightening are generally high-pressure valves. There are many types of valve connection. For example, some small valves that do not need to be removed are welded to the pipe; some non-metallic valves are connected by sockets, and so on. Valve users should be treated in accordance with the situation of Gu Xiu. 8 other There are many other valve connection forms. For example, some small valves that do not need to be removed are welded to the pipe; some non-metallic valves are connected by sockets, and so on. Valve users should be treated in accordance with the situation of Gu Xiu. Dongguan Guancheng Precision Plastic Manufacturing Co., Ltd. , https://www.dpowerchargers.com
