Pressure Switches

Pressure switches (or pressure sensors as they are also known), close an electric circuit when it detects that a certain set pressure has been reached. The pressure enters the mechanism, acts on the diaphragm or piston, which moves the plunger. This in turn moves and causes the contact disc to become disconnected. A piston is used for systems where there is higher pressure. The pressure switch can make contact either on a fall or rise in pressure whilst the parameters at which it works is adjustable. There are a number of different types of pressure switches. They can be operated by pneumatic or hydraulic means. Some pressure switches are installed with a vacuum (a sealed chamber) along with a diaphragm. For industrial use, the pressure switches are calibrated with a scale and pointer for precision work using complex machinery. Pressure switches have a number of applications. The sensor in the mat of automatic doors can be a type of pressure switch: the weight on the mat acting as the change in pressure. In general terms, pneumatic pressure switches are used for compressors, water pumps and other industrial machinery whilst hydraulic pressure switches tend to be installed in vehicles like cars.