Pressure switches with metal bellows: Stable repeatability, no risk of leakage

What advantages do pressure switches with metal bellows offer and what’s the foundation for these? The advantages are based on the seamless design of their measuring system. This solution enables permanently stable repeatability and, as well, eliminates the chance of leakage.
Bellows measuring systems derive from an adult manufacturing technology. The production of metal bellows, for example from stainless steel or perhaps a copper alloy, occurs in several steps. Circular discs are first cut from a flat piece of metal, and these are then shaped into cup-shaped objects. Dreadful softened through an annealing process in a furnace at more than 600 �C and then drawn into long, thin-walled and seamless tubes.
Constant elasticity
The tubes are corrugated by using forming tools at ruthless, and are trimmed to the designed size. In the next stage, the spring-like metal cylinders are pressed together in accordance with the specified dimensions (length, outer and inner diameter). This creates the constant elasticity needed for the stable repeatability of the movement. In the final step, the bellows are degreased and passivated, i.e. given a protective coating against corrosion.
Bellows manufactured from stainless for pressure switches
Seal-free functionality
In a pressure switch, the metal bellows is brazed or welded to the process connection. Its other end is in contact with the transmission mechanism. Because of this the instrument has a fully seamless measuring system with no need for any rubber sealing materials and the risk of leakage is eliminated. This feature makes pressure switches with metal bellows ideal for a variety of applications. Process reliability is also guaranteed with liquid media.
Permanent accuracy
A metal bellows changes its length based on the pressure. Whenever a defined switch point is reached, it triggers the switching function with a transmission mechanism. If the pressure drops or rises again, the bellows returns to its original shape and the switch contact returns to its original position.
The expansion movement of a metal bellows has a high linearity. The switch differential, that is precisely adjusted via a specific calibrated spring system, remains correspondingly constant. This ensures the accuracy of pressure control and switching, even over a long period of time.
Note
Detailed information on pressure switches with metal bellows, e.g. models PSM-520, PSM-550 and PSM-700, are available on the WIKA website. Missing Out want to buy pressure switches with metal bellows? In our WIKA online-shop you will discover some of our standard designs. Should you have any questions, your contact will gladly assist you to.g

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