Introduction to application industry in welding bellows

- Apr 27, 2019-

Introduction to application industry in welding bellows



Welded bellows double seal design if the bellows culvert failure, stem packing will also avoid leakage, and in line with international sealing standards; No fluid loss, reduce energy loss, improve plant equipment safety; Long service life, reduce maintenance times, reduce operating costs; Rugged bellows culvert seal design ensures zero leakage of stem and provides no-maintenance conditions; PTFE soft sealing material is used to improve the sealing performance of the valve. Resistance to high temperature of 425 or less cone seat is hard seal.


The welded bellows is a kind of thin hollow membrane formed by many stamping methods, which is made of highly flexible and telescopic metal tubes by precision welding, as shown in the figure. It is composed of two shaped hollow diaphragm in the form of concentric circle for the inner edge of the welding diaphragm pair, and then a number of diaphragm for the pile together for the outer edge of the welding corrugated section, and then at both ends and end plate metal welding combination of bellows group, so can be external needs and other moving parts together for reciprocating movement.


With the development of science and technology, the application field of welded bellows is expanding day by day. The main use of welding bellows is: as a control mechanism, transmitter or regulator detection components can also be used as temperature, pressure and liquid level measurement components, but also for a variety of sealing and energy transfer components.

Besides being used as measuring element, welded bellows can also be used as sealing, connecting, compensating and isolating element.


1. Instrument industry
Welded bellows are mainly used as pressure measuring elements in measuring and controlling instruments. The welded bellows can also be used as a volume compensation element in the gyroscope, a sealing and isolating element in the regulating valve, and a flexible coupling, a pressure switch, etc.
2. Aerospace
Welded bellows are also used in the aerospace field. In addition to being used in some of the instruments of the aircraft, welded bellows are also used in the automatic release pressure regulators of the parachutes. In addition, can also be used as a rocket engine on the shaft seal.
3.Electronics and other industries
Welded bellows are also used in electronic devices. For example, in the klystron of satellite communication ground station, micro-welded bellows with an outer diameter of 10mm, an inner diameter of 5mm and a wall thickness of 0.05mm are used. It is used as vacuum seal, axial connector, telescopic joint, oil reservoir, accumulator, etc.


Sawtooth type expander widely used in power industry is also a typical application example of welded bellows. The welded bellows actually act as a volume compensation here. The working coils of the voltage transformer and current transformer are all immersed in the insulated oil tank. Therefore, in a completely closed system, the volume change caused by thermal expansion and cold contraction of insulating oil must be compensated.


Welded bellows is a new type of component which has been developed at home and abroad in recent years. Welding bellows in addition to the pressure resistance, temperature resistance, corrosion resistance, good sealing, and other advantages, compared with the traditional shape of the bellows has two prominent advantages: large deformation, long life.


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