welded bellows industry application

The double sealing design of welded bellows can avoid leakage of valve stem packing if the bellows fails, And meet the international sealing standards; no fluid loss, reduce energy loss, improve the safety of plant equipment; long service life, reduce the number of maintenance, reduce operating costs; durable bellows seal design, ensure zero leakage of the stem, provide no maintenance conditions; welded bellows gas medium valve seat using PTFE soft sealing material to improve the sealing of the valve; high resistance The valve seat with temperature ≤ 425 ℃ adopts conical hard seal.

Welded bellows is a kind of highly flexible and retractable metal pipe made of many thin hollow diaphragms formed by stamping and precision welding. Its composition is composed of two hollow diaphragms formed by concentric circle inner edge welding to form a pair of diaphragms, and then a plurality of diaphragms are welded together by outer edge welding to form a corrugated section, and then the two ends and the end plate are welded together In this way, it can reciprocate with other moving parts according to the external needs.

With the development of science and technology, the application field of welded bellows is expanding day by day. The main uses of welded bellows are: as the detection element of control mechanism, transmitter or regulator, as well as the measurement element of temperature, pressure and liquid level, as well as various sealing and energy transfer elements.

In addition to being used as measuring elements, welded bellows can also be used as sealing, connecting, compensating and isolating elements, which have wide application prospects in many fields.

1. Instrumentation industry

Welded bellows are mainly used as pressure measuring elements in measuring and control instruments, which can replace bellows. The welded bellows can also be used as volume compensation element in gyroscope, as sealing isolation element in regulating valve, as flexible coupling, pressure switch, etc.

2. Aerospace field

Welded bellows are also used in the field of aviation and aerospace. Besides being used in some instruments of aircraft, welded bellows are also used in the automatic release pressure regulator of parachute. In addition, it can also be used as a shaft sealing door on a rocket engine.

3. Electronics and other industries

Welded bellows are also used in electronic devices. For example, a miniature welded bellows with an outer diameter of 10 mm, an inner diameter of 5 mm and a wall thickness of 0.05 mm is used in the klystron of satellite communication ground station. It is widely used in vacuum seal, axial connector, expansion joint, oil reservoir, accumulator and so on.

At present, sawtooth wave expander widely used in power industry is also a typical application example of welded bellows. The welded bellows actually play the role of volume compensation here. The working coils of voltage transformer and current transformer are immersed in the insulating oil tank. With the change of ambient temperature and working current, the temperature of insulating oil varies widely. Therefore, in a fully enclosed system, it is necessary to compensate the volume change caused by thermal expansion and cold contraction of insulating oil.

Welded bellows is a new type of component rising at home and abroad in recent years. Generally, welded bellows can be used as sensing element, sealing element, isolation medium, pipeline connection and temperature compensator. In addition to the advantages of pressure resistance, temperature resistance, corrosion resistance and good sealing performance, the welded bellows have two outstanding advantages compared with the traditional formed bellows: large deformation and long service life.

The choice of welding bellows material is very strict, in addition to the requirements of high temperature resistance, corrosion resistance, but also requires that the bellows have enough stiffness. The welding technologies used or being developed include tungsten inert gas welding, micro plasma welding, power beam welding and laser welding, among which micro plasma welding and laser welding are more commonly used.