Three-way direct acting solenoid valves work in almost the same way as a two-way direct acting solenoid valve. The fixed core has an exhaust orifice running through it. The plunger has an upper seal and lower seal allowing flow to or from either the body seat or exhaust seat depending on the configuration.
Applications using three way solenoid valves
As three way solenoid valves operate in the same manner as two way direct operating solenoid valves they have similar applications.
Direct acting solenoid valves are suitable for fast and frequent operation. Direct acting solenoid valves are useful when there are lower flow rates because of a smaller orifice. They can be used with many media including water, air, steam, oil or any media compatible with the wetted materials. Typical applications include coffee cartridge, air dryer, hydro sauna and weed killing equipment. Direct acting solenoid valves can also be used in vacuum applications, for example in a vacuum pump system.
Nickel plating can protect brass bodies against corrosion that may be caused by cleaning detergents. Nickel plating versions of direct acting solenoid valves are available and can be useful in applications where car washing equipment is being produced. This is also a very inexpensive way to prolong valve life.
Car Washing System Applications
Self service car washing systems and vital to the car washing industry as they can cover vehicles that traditional car washes cannot clean such as motorcycles, caravans and small boats. High pressure water is mixed with wax, detergent and car washing foam and delivered through a lance and a brush. During the shampooing cycle two solenoid valves let hot and cold water in to the cycle. Three more solenoid valves are used inside the circuit to intercept the liquid detergent, foam and wax and mix them with water. A pump sucks up the mixture and lets it back in to the system at 80bar. Before it reaches the brush, the liquid is mixed with air. The lance gun shoots water or shampoo under pressure according to the selected cleaning cycle.
Coffee Dispensers in Vending Machines
Soluble beverages such as coffee can be supplied in cartridges and mixed with water when needed. The coffee cartridge is expelled in to a special container once it is needed. Here there are cabinets for a cup dispenser, spoon and sugar and a product storage compartment with a door. These machines are widely used in households and in other industries such as shops, offices, hotels.
Water is stored in a tank and when required can be sucked up by a vibrating pump. It is then intercepted by two three way solenoid valves. One supplies the hydraulic actuator and the other delivers water to the boiler. The operation starts when the cartridge is in, the two solenoid valves open at the same time and the actuator pushes the boiler downwards against the cartridge. There is a safety valve above the second solenoid valve that prevents water from flowing out before the actuator has descended completely. When there is a pressure of about 10 bar in the circuit the safety valve will open and cold water will flow in to the boiler while water that was already warmed flows out and filters through the cartridge. The solute produced i.e. coffee, tea, hot chocolate flows through a nozzle in to the cup. At the end of the cycle the second solenoid valve closes and exhausts the remaining hot water under overpressure from the third way in to the collecting tank. Next the first solenoid valve closes and water under pressure inside the actuator is exhausted from the third way in to the tank. When only hot water is required a two way solenoid valve directly connected to the boiler intercepts hot water and pours it directly into the cup through a different nozzle.
For more advice and information on how M&M International solenoid valves can be used in your application, please contact our technical team on +44 (0) 8444 501123.