What advantages do pressure switches with metal bellows offer and what is the basis for these? Advantages are based on the seamless design of these measuring system. This solution enables permanently stable repeatability and, simultaneously, eliminates the chance of leakage.
Bellows measuring systems derive from a mature manufacturing technology. The production of metal bellows, for example from stainless steel or perhaps a copper alloy, takes place in a number of steps. Circular discs are first cut from a flat little bit of metal, and these are then shaped into cup-shaped objects. They are softened through an annealing process in a furnace at more than 600 �C and drawn into long, thin-walled and seamless tubes.
Brazen are corrugated through the use of 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 necessary 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. This means that the instrument has a fully seamless measuring system with no need for any rubber sealing materials and the chance of leakage is eliminated. This feature makes pressure switches with metal bellows ideal for an array of applications. Process reliability is also guaranteed with liquid media.
Permanent accuracy
A metal bellows changes its length good pressure. When a defined switch point is reached, it triggers the switching function via 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 includes a high linearity. The switch differential, which is precisely adjusted with 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 home elevators pressure switches with metal bellows, e.g. models PSM-520, PSM-550 and PSM-700, are available on the WIKA website. You would like to buy pressure switches with metal bellows? In our WIKA online-shop you will find some of our standard designs. Should you have any questions, your contact will gladly assist you to.