A solenoid valve is operated by one or two solenoids, the solenoid is to convert electrical energy into magnetic energy , then magnetic energy into mechanical energy, the solenoid is mounted on the valve housing to become a valve, it can be used in the hydraulic, pneumatic and water industry. – finotek.com
Electro-mechanically operated valve is known as solenoid valve. Through solenoid; the opening valve is controlled by an electric current. The flow is switched on or off in case of two-port flow and the outflow are switching between the two outlet ports; in case of three-port valve. Solenoid valves are mostly used as hydraulic solenoid valves in controlling the elements in fluid. Pneumatic and hydraulics are the basis of fluidics, based on fluid dynamics. The task of hydraulic solenoid valves in fluidics are to distribute, shut off, dose, mix or release the fluid. Long service life, compact design, high reliability, low control, power and safe switching are the services offered by solenoid valves. On a manifold; many solenoid valves can be placed together and rocker actuators, plunger-type actuator and pivoted-armature actuators are the type of solenoid valves that are used. Beside of this the most frequently used of these is plunger-type actuator.
ASCO Numatics was the first company in 1910 that started to develop and manufacture solenoid valves. The design variations of solenoid valves are many and it can have a number of fluid paths and ports. In a 2-way / 2-port valve, if the valve is open, then there is a connection between the two ports and fluid flows between the two ports and the ports are isolated if the valve is closed. In non-energized condition of solenoid if the valve is open then it is termed as normally open (N.O) valve and if the valve is closed on the same condition then the valve is termed as normally closed (N.C) valve. There are also 3-way, 4-way valves and more with complicated designs and all these valves with media of hydraulic oil known as hydraulic directional solenoid valves.
A directional control valves or hydraulic directional solenoid valves are one of the most basic and fundamental parts in pneumatic and hydraulic machinery. The function of this type of valves is to allow the flow of fluid from one or more sources into different paths. The cylinder of the solenoid valve is mainly mounted with spool which is controlled electrically or mechanically. The spool’s movement restricts the fluid flow, hence known as a control valve.
Higher forces are required when large orifices and high pressures are encountered and in order to generate these forces, a design a hydraulically solenoid operated directional spool control valve is used. To generate high valve forces, line pressure is used and this line pressure is controlled by small solenoid valve. A very less amount of power is required to control piloted valves but it is a little bit slower.
The two main parts of a solenoid valve are the solenoid and the valve. The function of the solenoid is to convert electrical energy into mechanical energy and this in turn is used for opening and closing of valve mechanically. A solenoid valves may use rubber seals or a metal seal and can have electrical interfaces for easy control of the valve. Sometimes a spring is used in hydraulic solenoid valves for normally open and normally closed function while there is no activation of valve.
The components of solenoid valve are retaining clip, core tube, core, plug-nut, core spring, solenoid coil, bonnet, hanger spring, valve housing and O-rings or backup washer. The magnetic component of the solenoid is a plunger or core which moves when the solenoid is energized. The core is placed co-axially with the solenoid and the movement of core will break or make the seals which in turn controls the fluid movement. The spring holds the core in the normal position when the core is not energized and the plug-nut is also placed co-axially. The core is placed in core tube and these guides the core. It also has plug-nut contained in it. A shunt path is offered for the field lines if the core tube is magnetic. Hence the core tube should be always non-magnetic in order to optimize the movement of the core. The coil of the solenoid consists of many numbers of turns of copper wire, which surrounds the core tube and is used to induce the core’s movement. Epoxy is used to encapsulate the coil and for low magnetic path resistance, iron frame is used for the coil.
The most common material used for the production of solenoid valve are casting iron, carbon steel, stainless steel, in order to make the body compatible with the hydraulic pressure fluid. In order to make the seals compatible with the fluid, the O-rings, the plug-nut, springs, core and other components are exposed to the fluid. The core tube is made up of non-magnetic material as to pass the field of solenoid through the core and plug-nut and both these materials should be made up of material that has a good magnetic property like iron or steel. Hence material like stainless steel is used sometimes as it comes in both magnetic and nonmagnetic materials. A stainless steel solenoid valve for example, can use 305 stainless steel for the core tube, for the body; a 304 stainless steel, 302 stainless steel for the springs and stainless steel of 430 F for the plug-nut and core.
Solenoid valves are used as hydraulic directional solenoid valves and hydraulic solenoid valves in the fluid power of the hydraulic systems. Solenoid valves are used in automatic irrigation sprinkler systems with an automatic controller. In order to control the water entry into the domestic dishwashers and washing machines, solenoid valves are used. In dentist chairs; solenoid valves are used to control the water and air flow. Solenoid valves are simply referred as ” Solenoid ” in the paintball industry and these are used to control a larger valve that is used to control the propellant. These valves are also now used in household purifiers (RO systems) as well. Besides controlling the flow of fluids and air, solenoids are used especially for patch-clamp in the pharmacology experiments, which controls the application of both antagonist and agonist. A solenoid valve is also used in steam boilers, plastic molding machinery, vacuum and compressors, in coffee machines and in gas boilers to control the flow of gas to the burner. You see, the industrial parts will often be found beside us, same working principle but showing different appearance shapes.