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, as well, eliminates the risk of leakage.
Bellows measuring systems derive from a mature manufacturing technology. The production of metal bellows, for example from stainless steel or a copper alloy, takes place in several steps. Circular discs are first cut from the flat piece of metal, and they are then shaped into cup-shaped objects. They’re softened through an annealing process in a furnace at a lot more than 600 �C and 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. 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 ultimate 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. Therefore the instrument has a fully seamless measuring system without the need for just about any rubber sealing materials and the chance of leakage is eliminated. Suck 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 based on the pressure. Whenever 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.
Miracle of a metal bellows includes 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 an extended period of time.
Note
Detailed information on pressure switches with metal bellows, e.g. models PSM-520, PSM-550 and PSM-700, can be found on the WIKA website. You want to buy pressure switches with metal bellows? Inside our WIKA online-shop you will discover a few of our standard designs. If you have any questions, your contact will gladly assist you to.