A pressure switch is actually a type of mechanical switch that makes an electric contact when a particular amount of pressure is reached with the input. They are generally used for offering automatic on/off switching from a hydraulic or pneumatic source. The pressure switch can be specially designed to react to either a fall in pressure or a rise in the pressure.
When selecting a pressure switch for protecting equipment, products or operators, you should essentially consider deadband, set point and reliability. Pressure switches are generally used in plants across the globe for an extensive range of control, shutdown and alarm applications. They are economical means for protecting equipment and operators by sensing when the pressure drops down or rises up beyond safe levels.
Once the pressure rise or drop is determined, an electrical signal is then sent to control the equipment or to activate an alarm. Set point refers to a pressure level where the control function or alarm is set to occur. Generally, most pressure switches enable physical set-point changes in the field. However, some manufacturers also provide models with two different set points for both minimum and maximum pressure alarm applications.
On the other hand, a deadband is actually a difference between reset points and set points resulting from the inefficiencies in mechanical parts of the switches. While some pressure switches include deadband adjustments, others have non-adjustable, fixed deadbands. So, when it comes to selecting pressure switches you need to choose the one that can best suit your requirements.
