Metal bellows are commonly used in bridge construction. Different structures have different characteristics, and different structures will reflect different waveforms. Waveform refers to the corrugated shape and shape after cutting along the axial direction. The waveform of the bellows basically has U-shaped C-shaped, Ω-shaped and S-shaped. In order to improve the pressure bearing capacity and reduce the rigidity, multi-layer bellows and bellows with reinforcement rings are introduced.
Generally, the circular cross-section is very good at withstanding high pressure, but the displacement may be small. The U-shaped cross section allows large displacements and relatively low pressure capacity. Generally, the wave shape commonly used in China is U-shaped corrugation. Under the conditions of withstanding high working pressure and large displacement, a multi-layer U-shaped corrugated structure is adopted. C-shaped bellows have high rigidity, poor sensitivity and large nonlinear error. They are usually used as seal isolation components or flexible couplings. Ω-type and S-type bellows are mainly used for high working pressure and small working displacement. For example, it is used as a sealing and isolation component on high-pressure valves.
End structure of metal bellows
There are 5 basic structure types for the end structure of the connecting pieces at both ends of the bellows:
(1) Internal coordination is represented by N
(2) External coordination is represented by W
(3) The closed bottom is indicated by D
(4) Peak QD meter has no straight wall cutoff
(5) There is no straight wall truncation at the trough indicated by Qd
The structures at both ends of the bellows are arbitrarily combined by the above five structures, and the same kind of bellows can be combined into 14 structures.
Both ends of the bellows need to be welded with the connected parts. Brass, tin bronze and beryllium bronze materials are brazed or silver welded; argon arc welding, roll welding and electron beam welding methods can be used for stainless steel and Inconel 718 and other materials. The end structure of the bellows affects the formation process of the bellows. Among them, the W-shaped structure has the best manufacturability, it is recommended to use it first. The N-type structure has poor manufacturability, and its diameters D1 and L1 lengths are best selected according to relevant standards and product samples. rupture.