Ice cube makers, refrigerators, and dishwashers are a few home appliances that operate with 12 volt solenoid valves, which are most often pneumatic but can also be hydraulic. A wide range of industries use 12v solenoid valves to power industrial tools and motors, for heating and cooling, electronic, medical, dental equipment, oil tooling, aerospace, fuel systems, and automotive.
12 volt hydraulic valves regulate the flow of fluid or water, while 12 volt air or pneumatic valves regulate the flow of gas or air. Ideal for low volume vacuum or air pressure applications, 12 volt solenoid valves can be made from either plastics or metallic elements and alloys.
The 12v refers to the amount of voltage required to operate the solenoid valve. There are also 3v, 6v, and 24v solenoid valves; however, 12 volt solenoid valves are the standard. Also powered by natural pressure and electromagnetic force, 12v solenoid valves have fewer moving parts. This is an advantage considering moving parts require maintenance.
12 volt solenoid valves control the flow of gasses or liquids through tubes, as regular valves do, but unlike other valves, can be easily operated by remote devices that activate the solenoid coil. The ability to be controlled remotely makes 12 volt solenoid valves extremely useful for operating potentially dangerous machinery or inaccessible lines.
12v solenoid valves are operated electromechanically by a solenoid, which is a magnetized coil activated by electrical charges, which controls the flow of gasses or liquids precisely through targeted electrical charges, sensor cue or by hysteresis (device memory).
12 volt solenoid valve manufacturers make two general types of valves: direct-acting and pilot-operated. Direct-acting 12v solenoid valves have a plunger that is in direct contact with the in-flow opening in the valve body, or orifice. This plunger is used to open and close the orifice, which permits or hinders flow. The pilot-operated 12 volt solenoid valve, which is actually a combination of a pneumatic or hydraulic valve and a smaller solenoid valve, works with a diaphragm rather than a plunger, using differential pressure to control the flow of gasses or fluids.
In addition, 12 volt solenoid valves must be either a normally closed (NC) valve or a normally open (NO) valve. In an NC valve, a plunging pin or rod within the valve is held blocking the passage of air or fluid by a solenoid coil; the air or fluid pressure coming into the valve helps keep the valve shut as long as the pin blocks the passage. In order for gas or fluid to flow through the valve, an electromagnetic charge is run through the solenoid coil, which becomes active and lifts the plunger out of the passage and allows flow through the entire valve. NO valves are the opposite; they remain open until the solenoid is activated and pushes down the plunger, blocking flow and creating pressure to keep the valve closed.