1. Bellows, welded or convoluted (formed) are used in a large number of industrial applications. Below you will find a few;

2. Load cells; A load cell deforms if a certain load in the form of a pressure or a strain is imposed on it. This deformation is then detected by a strain gauge through which a low voltage direct current is flowing. The change in voltage is detected and made visible on a control panel. To protect this strain gauge from outside damages or weather influences a bellows is mounted over the gauge to protect it from outside influences.

3. Vacuum interrupters; For the switching of very high voltages in transformer stations sparks should be avoided. To prevent any danger that the surrounding atmosphere will explode, oxygen has to be removed in the area where the sparks occur. This can be done by sealing the spark area completely. Bellows are used to seal such confined volumes and the inside of the bellows is evacuated or filled with an inert gas.

4. Mechanical Seals; These are mostly used to close the inside of a pump from the outside world to prevent leakage. For that purpose, a mechanical seal is mounted on the pump shaft. As the pump shaft is turning, there has to a rotating sealing element consisting of a stationary and a rotating ring. To enforce sufficient pressure on the two rings one is fitted with a spring. This spring can also have the form of a diaphragm (welded) bellow.

5. Pressure gauges: If the pressure of aggressive fluids or gases has to be measured, the gauge has to be isolated from the flow. For critical applications a diaphragm sealing is used instead of a bourdon tube in the gauge. This gives more security that the aggressive media will not leak. The diaphragm is a self contained sensor, transmitting the displacement to the measuring device.

6. Sensors: In this application diaphragm or convoluted bellows are completely sealed and filled with a certain gas. Two electrical poles are penetrating the inside of the bellows. By varying the current of those two poles the temperature inside the bellows can be regulated. The expansion or contraction of the bellows is used as an actuator to control a certain movement.

7. Valve Sealing: A bellows is used between the housing and the rising stem to seal the inside completely from the outside world. In Europe this is of particular importance as regulations such as TA Luft prohibit any leakage.