In the direct acting-valve, the valve gets activated by the solenoid which pulls a plunger or piston to block air or fluid from flowing. In some solenoid valves, the conduit is not directly opened by the electromagnetic field. In a pilot operated valve, a solenoid moves the plunger that creates the small opening and the pressure created by that small opening operates the valve seal.
In both the valves the electric current needs to flow continuously through the solenoid, because once the current is stopped the electromagnetic fields will disperse and the valve will return to its closed position.
In automobiles, starter solenoid acts as a relay that brings metal contact into place to close the circuit. Starter solenoid receives small current when automobile ignition is activated, by the turn of a key or start button. This renders the magnetic field of starter solenoid to pull on the contacts, thus closing the circuit between the starter motor and car’s battery. The solenoid needs continuous electric supply to maintain the circuit, but as the engine starts, it gets self-powered and the solenoid gets de-activated.
Moreover, these can be used in particular type of locking systems in the doors that use an electromagnet and offer secure closure. The solenoid is used in various appliances and products like fuel injection gear system, computer printers, doorbells and in many more products. They are versatile and can be found in everything from paintball guns to automated industries. They give quick response which makes them the most significantly used tool for different purposes.