Pressure Switches

Pressure switches are precision instruments designed to maintain, monitor, and manage the pressure levels within industrial systems. By monitoring and responding to pressure changes, pressure switches help automate processes, ensure safety, and protect equipment from damage due to abnormal pressure conditions. Whether mechanical or electronic, pressure switches provide reliable and cost-effective pressure control, making them indispensable components in numerous systems.

The pressure switches sensing element, which could be a diaphragm, piston, bellows, or Bourdon tube, is exposed to the system's fluid pressure, as the pressure changes, the sensing element moves or deforms in response to the pressure differential. The switch has an adjustable setpoint mechanism, usually a spring and screw, which allows the user to set the pressure level at which the switch will activate or deactivate. This setpoint defines the pressure at which the electrical contacts within the switch will change state (either open or close). The electrical contacts are the components that open or close the circuit when the pressure reaches the setpoint. The switch can be configured as normally open (NO) or normally closed (NC), depending on whether it completes or interrupts a circuit when the set pressure is reached. When the pressure reaches the setpoint, the force exerted on the sensing element causes the switch's internal mechanism to actuate the electrical contacts, either opening or closing them to control the connected device or system.

Mechanical pressure switches operate based on mechanical movement of the pressure sensing element, typically using springs, diaphragms, or pistons to actuate the switch contacts. Mechanical pressure switches are suitable for many standard applications due to their reliability and simplicity. Electronic pressure switches use electronic sensors (such as piezoelectric or strain gauge sensors) to detect pressure changes, and provide more precise control and can offer features like digital displays, programmable setpoints, and remote monitoring. They are ideal for applications requiring high accuracy, frequent switching, or integration into digital control systems. Differential pressure switches monitor the difference in pressure between two points in a system and are used in applications like filter monitoring or leak detection, where the pressure differential between two points is critical.

Pressure switches are used to automatically start or stop pumps or compressors based on the system's pressure. For example, a pressure switch in a water pump system will turn the pump on when pressure drops below a certain point and off when it reaches the desired level. Pressure switches provide safety functions by activating alarms or shutting down equipment when pressures exceed or fall below safe operating limits, protecting both equipment and personnel. In heating, ventilation, and air conditioning (HVAC) systems, pressure switches monitor refrigerant or air pressures to control compressors, fans, and other components, ensuring efficient operation and preventing damage. Pressure switches can detect a pressure drop across filters in air or fluid systems, indicating that the filter is clogged and needs replacement or cleaning. Pressure switches are used in hydraulic and pneumatic systems to control actuators, motors, or valves, ensuring proper pressure is maintained for smooth and efficient operation. The are very useful in various industrial process control industries, such as chemical, oil and gas, and food processing, to maintain pressure levels within safe and optimal ranges for different stages of production.

Mechanical pressure switches have many advantages, as they are robust and have few moving parts, making them reliable for many applications with minimal maintenance. Pressure switches are generally more affordable than more complex pressure sensors or transmitters, making them suitable for basic control or safety applications. Pressure switches can be used in a wide range of applications and industries, from HVAC and water systems to heavy industrial processes. The setpoints are adjustable, allowing users to customize the pressure levels at which the switch activates or deactivates according to specific operational requirements.