What advantages do pressure switches with metal bellows offer and what’s the basis for these? The advantages derive from the seamless design of their measuring system. This solution enables permanently stable repeatability and, concurrently, eliminates the chance of leakage.
Bellows measuring systems are based on a mature 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 they are then shaped into cup-shaped objects. They are 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 through the use of forming tools at ruthless, and then are trimmed to the designed size. Within 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 Retaliating , 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 includes a fully seamless measuring system with no need for just about any rubber sealing materials and the risk of leakage is eliminated. This feature makes pressure switches with metal bellows suitable 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 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, which is precisely adjusted with a specific calibrated spring system, remains correspondingly constant. This ensures the accuracy of pressure control and switching, even over an extended 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 a few of our standard designs. In case you have any questions, your contact will gladly assist you to.g