Flexible sensing element for the instrument, which has a high requirement for the elastic properties of the corrugated pipe as an elastic sensitive element. The corrugated tube used as an elastic sensitive element is essentially a pressure displacement output or a pressure change into a concentrated force output. The pressure is concentrated force output ripple tube deformation is very small or almost no displacement, so on the ripples produced by stress than the output displacement of the corrugated pipe stress wave, to elastic aftereffect, lag effects can be said not, therefore, force balance type corrugated pipe for the reliability and accuracy of the elastic sensitive element of the instrument can be very high. This is in the measuring instrument, multi force balance type corrugated tube elastic sensitive element, the pressure variable displacement output of the corrugated tube may result in greater pressure on the corrugated, should pay attention to the design, also elastic aftereffect, lag had certain influence on the elasticity of the corrugated pipe.
Corrugated metal pipe is characterized in that the pressure, axial force, lateral force or bending moment can produce the corresponding displacement, and has the pressure, vacuum sealing, corrosion resistance, temperature stability and long service life. Therefore, it has been widely used in many industrial fields. Its main application in the following aspects.
In the instrument as an elastic sensitive element of the bellows, the design of the corrugated pipe stiffness as small as possible. Temperature control and temperature measurement can be used to change the volume of the cavity (or outside) in the process of displacement.
Vacuum switch is the key component of vacuum arc extinguishing chamber. The main contact is the key element in the vacuum arc extinguishing chamber. Only the metal bellows are used to make the contact movement and the vacuum arc extinguishing chamber. The vacuum switch every time and break, the corrugated pipe for a large displacement, a large and frequent axial displacement is easy to make the corrugated tube due to fatigue and damage. Corrugated pipe is an important part of the vacuum arc extinguishing chamber shell. If it is damaged, the life of the vacuum arc extinguishing chamber is terminated by a leak. The other parts of the vacuum arc extinguish chamber are not easy to damage, so the fatigue life of the corrugated tube is determined by the mechanical life of the vacuum arc extinguishing chamber. In addition, the actual axial displacement is equal to the actual axial displacement of the vacuum switch. Therefore, the axial displacement of the corrugated pipe can be determined by the maximum contact distance.

The fatigue life of the corrugated pipe is related to its structure and the materials used, and it also has a great relationship with the conditions of use. The working stroke of the corrugated pipe used in the vacuum switch has a great influence on its fatigue life. The same kind of corrugated pipe, the same kind of vacuum switch, in order to get a longer fatigue life, only to reduce the work of the corrugated pipe or contact distance can be achieved. In contrast, if the increase in the work of the corrugated pipe or contact distance, the fatigue life of the bellows will be greatly shortened. Therefore, the main performance of the corrugated pipe used in the vacuum switch is the axial displacement and the vacuum seal. There are two kinds of working state, on or off, in the vacuum switch, the corrugated pipe needs to be stretched and deformed, and the corrugated tube is compressed and deformed in order to guarantee the service life of the vacuum switch.
Corrugated pipe and welded corrugated pipe can meet the requirements of the use of ordinary vacuum switches, taking into account the cost of manufacturing, the general vacuum switch are used in the hydraulic forming corrugated pipe. Only the use of a vacuum switch with a long service life and a large contact stroke is used for welding corrugated pipe. Corrugated pipe materials are generally stainless steel 00Cr17Ni14Mo2, 0Cr18Ni9 and 1Cr18Ni9Ti, etc..
For flexible coupling of metal hose, metal hose is used to compensate for the position deviation caused by the installation of the pipe system and the requirement of the working end displacement, and the fluid pressure of the system. The core part of the metal tube is a corrugated pipe, the ratio of the length and diameter of the corrugated pipe is more than 3, the wave type is divided into annular and spiral shape, and the bending rigidity of the ring is smaller than that of the spiral type. In order to increase the bearing ability of the metal hose, in many cases, the corrugated pipe outside the armored metal wire or woven with metal net.
For corrugated tube heat exchanger for heat transfer, the corrugated tube heat exchanger is an effective and enhanced heat exchanger, which is a combination of metal forming, mechanics and heat transfer. As heat transfer tube bundle, the corrugated tube is mainly used to enhance heat transfer, and the effect of heat compensation and anti vibration is also played. The failure mode of corrugated pipe is mainly fatigue cracking, stress corrosion cracking and corrosion cracking. In the corrugated tube heat exchanger, the main performance of the corrugated pipe is heat exchange efficiency, fatigue life, pressure, temperature, corrosion resistance, anti vibration and thermal compensation, etc.. The heat transfer efficiency is mainly related to the waveform, and the wave shape affects the forming process of the corrugated pipe.
Valve for sealing isolation components, bellows valve, whether it is the valve, throttle valve, control valve, or valve, bellows valve, bellows are as the valve stem without the packing sealing element. In the work of the valve, bellows and valve stem together for axial displacement and reduction, but it also bears the pressure of the fluid and the absolute seal. The axial displacement of the corrugated pipe is related to the diameter of the valve, and the working stroke of the corrugated pipe is generally 1/4. The axial displacement of the corrugated pipe should be limited by the mechanical limit of the valve stem. Corrugated pipe is not allowed to rely on a plastic deformation, but also to prevent the distortion of the corrugated tube. In the valve, the main use of corrugated pipe is the pressure, the work of displacement and fatigue life. The failure mode of corrugated pipe is fatigue fracture, stress corrosion damage and instability of bellows. The factors that affect the service life of corrugated pipe are working pressure, working displacement, working temperature, fluid medium, wave structure, the quality of raw materials, pressure, vibration, connecting parts and assembly quality. Corrugated pipe is the most easily damaged parts, so the design and selection of corrugated pipe is very important, if the design is not reasonable, often lead to premature valve failure. Compared with the packing seal valve, bellows valve has a higher reliability and service life. It has been widely used in the nuclear industry, petroleum, chemical, pharmaceutical, aerospace and other industrial fields.
For metal corrugated expansion joints, metal corrugated expansion joints are widely used in various piping systems to compensate for the axial, lateral and angular displacement caused by temperature and pressure fluctuations. Metal bellows expansion joints are the core part of the corrugated pipe, through the corrugated pipe can be deformed and pressure seal to carry out pumping, horizontal and angular displacement, and bear the pressure of the system, the other parts are structural parts, starting guidance, support, connection, diversion and other functions. According to the design and use requirements, the corrugated pipe and the structural parts are welded into the axial, transverse and angular direction to different types of corrugated expansion joints.