A vent control solenoid is an electromagnetic actuator used to open and close gate or louver-type ventilation and air conditioning vents. These solenoids typically feature low-voltage coils and are controlled manually or by an automated system. The vent solenoid usually produces only the opening motivation, with a return spring or system air pressure used to close the vents again. Vent solenoids are commonly-used air flow control devices in domestic, industrial, and automotive air circulation systems. The term "vent solenoid" may also be used to describe the solenoid-operated vent valves on pressure chambers.
Gate or louvered vents are widely used as air circulation entry and exit points in ventilation and air conditioning systems. The vents may be static types that remain open at all times, be adjustable through a range of positions, or be of a two-position, open, or closed design. The latter type of vents are typically actuated by a vent control solenoid via a manual switch or the control circuit of an automated ventilation system. In some cases, the solenoid may be fitted with a mains voltage coil, but most have low-voltage coils, typically rated between 12 and 24 volts, many fed by solar charged batteries. Where the vents are used as entry or exit points in rooms, the solenoid is usually mounted on the inside of the vent assembly where it is not visible.
These devices function in the same way as all solenoids and feature a standard hollow-cored wire coil and a metal plunger. A suitably rated voltage is sent to the coil via a control circuit, causing a magnetic field to form around it. This magnetic force then rapidly pulls the plunger into the coil core. The operating arm for the vent is connected to the plunger via a linkage, the movement of which opens the vent when the plunger moves.
Most vent control solenoid models only supply the opening movement for the vent, and a return spring is then used to close the vents again when the solenoid power is cut. In some cases, the vents may also be closed by the pressure of the air traveling through the system. Common applications for the vent control solenoid as air flow controllers are industrial, domestic, and automotive air conditioning and ventilation systems. The vent control solenoid identifier is often used to describe manual or automated pressure relief vent valves. These valves are installed on pressure vessels where they function as purge or relief devices for venting the pressure within the vessel when repairs or maintenance are required.