Because the solenoid coil is activated electrically, the valve can be switched remotely by programming, sensors, or device memory. Consisting of a solenoid coil and a valve, solenoid valves function by converting electrical energy into mechanical energy, which can open or close the valve in order to shut off, release, or distribute the fluids or gasses such as air. Solenoid valves are chosen above other types of valves such as butterfly or ball valves because solenoids offer the unique capacity for being activated remotely, by sensor cue or by hysteresis (the device’s memory).
Water valves are made from a variety of materials including plastics or metals. Stainless steel is commonly used because of its sanitary and corrosion-resistant qualities. Solenoid water valves are used widely in home appliances such as washing machines, dishwashers, ice makers, and refrigerators. Industrial and commercial businesses use solenoid water valves in applications such as vending machines, sensor-activated water faucets, sprinkler or irrigation systems, and many others which require triggered water flow.
The types of valves which are considered solenoid water valves are typically normally closed (NC), which is to say that the valve’s inactive state blocks the flow of water and releases flow when activated.
Water solenoids are also typically pilot-operated diaphragm valves, as opposed to direct-acting. Where direct-acting solenoids have a plunger in direct contact with the valve’s inlet, opening and closing the valve to permit and hinder flow, the pilot-operated solenoid is actually a combination of a pneumatic valve and a smaller solenoid valve. Pilot-operated solenoid valves work with a diaphragm rather than a plunger, using differential pressure to release or hinder flow. Pressure is controlled by a small solenoid vent chamber which activates the valve by lifting a vent and changing internal pressure.
Pilot-operated water valves, often referred to as hydraulic valves, are often used to pneumatically control water flow in home washing appliances. Solenoid water valves are usually pilot-operated rather than direct-acting since water pressure within the valve provides a secure seal and the pilot solenoid requires relatively little power to activate the valve. Thus, in appliances such as washing machines, in which water must be triggered at specific times, solenoid water valves provide a sealed, easily activated solution to timed water flow control.