Solenoid valves are also available at SIO that come in various materials and specifications. Also called electrically-operated valves, these valves are automatic valves that will no longer need a professional to operate them manually. They function through the use of electromagnetic solenoid coils to alter the state of the valve from open to shut and vice-versa.
Solenoid valves are useful in applications that involve clean process media, like clean liquids, gases, and oils, that need to be managed. Basic on and off valves are the most used as several process lines only require flow/ no flow features. Solenoid valves are also useful in factories where there is no compressed air available.
You can depend on SIO to offer you the best solenoid valves that are compatible with an array of applications!
A solenoid valve is a valve that allows fluid flow or shut off when it is electrically energized or de-energized. It converts electrical energy to mechanical energy, which results to the creation of a magnetic reaction as the electric current approaches the wire in the solenoid. The actuator of a solenoid valve is in the form of an electromagnet.
The valve has an electric coil, called a solenoid, that has a ferromagnetic core in the center. The core is coined as the plunger. A magnetic field builds up to pull a plunger or pivoted armature against spring’s action when energized. The pivoted armature or plunger returns to its original state by the operation of a spring when it is de-energized.
Solenoid valves are widely used in liquid and gas circuits. These valves can be applied in several operations like heating systems, industrial automation, swimming pools, compressed air technology, sprinkler systems, dental equipment, irrigation systems, washing machines, and even car wash systems.
The body of the valve is where the solenoid valve is connected with the pipeline to regulate the flow of the fluid. But since solenoid valves are automatically actuated, they are connected directly to the body.
The inlet port is where the fluid enters to flow through the automatic valve. As the fluid passes to the inlet port, the flow can proceed to the other stages of the valve operation.
The outlet port is where the fluid enters to leave after passing through the valve. The solenoid valve takes control of the fluid flow from the inlet to the outlet ports. A fluid in the whole process eventually enters the outlet port.
The solenoid is considered the body of the solenoid coil. With its metallic finish and steel components, the solenoid is cylindrically shaped and hollow. The coil is located on the upper part inside the solenoid valve.
The solenoid is composed of several turns of coil, also called coil windings, wound up around the ferromagnetic material in the valve. The shape of a hollow cylinder is formed by the coil which is covered by steel. This coil has a hollow part where a plunger or piston is located. The spring controls the motion of the piston.
Lead wires are external connections in the solenoid valve, which are directly connected to the electrical supply. These wires serve as the pathway for the current to pass through the solenoid valve. Once the valve is energized, the current flows through the lead wires to the valve. When the valve is in the de-energized state, the fluid flow stops.
The plunger or piston is the cylindrically shaped solid metallic part that is located in the hollow portion of the solenoid valve. When the electrical energy passes through the solenoid valve, the formation of the magnetic field happens inside the hollow space.
Once the field has been created, the plunger moves in a vertical motion. It remains in its current place once the supply of electrical current stops and the creation of the magnetic field ceases.
Because of the spring force that pushes against the magnetic field, the plunger is in movement inside the space. The magnetic force created in the hollow space of the solenoid valve causes the plunger to move, but the spring prevents the movement. The spring force against the generated magnetic field makes sure that the plunger is located in the area where the current flow is blocked from passing through the valve.
The spring plays a crucial role inside the hollow space. First, the spring maintains the favored position of the plunger instead of letting the plunger fall down because of gravity once the flow of the current through the solenoid valve is blocked. Second, the spring stops the plunger from moving because of the flow of fluid force in the valve body. The plunger moves up when the liquid is available and goes down when the liquid flow stops when the spring is not around. In order for the piston to take control of the fluid, the spring should be present to force it.
This is where the fluid flows in the solenoid valve. The orifice connects the inlet port and outlet port. The fluid flow that starts in the inlet to the outlet happens in the orifice.
In ordinary valves, the orifice is covered with the disc found at the bottom of the stem where the handle is connected. Thus, the handle controls the opening of the orifice. However, for solenoid valves, the plunger, which is controlled by the spring and the current that flows through the solenoid valve, opens the orifice.
In choosing solenoid valves for your industrial applications, here are some things to consider:
To find the right type of solenoid valves for your perusal, you have to know the type of media they will be used for. In general, these valves are primarily designed to operate with media having no solid articles such as oil, steam, heat transfer fluids, water, petroleum products, and compressed air. By knowing the type of media, you will know what materials your solenoid valves should be made of.
Solenoid valves can be made from brass which is ideal for fuel, water, inert gas, or air, stainless steel for applications with corrosive fluids or food product liquids, or plastic for food and chemical industries.
Solenoid valves can have two or more ports. Two digits often define them; one determines the number of ports, while the other digit talks about the number of positions. Most solenoid valves use an on or off basis to be operated. Some of these valves, however, are used to keep the proportion of the valve to the current or supply voltage.
You can either choose normally open (NO) or normally closed (NC) solenoid valves to optimize the supply time of your solenoid valve, depending on the applications where the valves will be used. When the valves are powered by electricity, a normally open solenoid valve opens the valve, and a normally closed solenoid valve closes and prevents the flow of the fluid. If needed, you may consider choosing a bistable solenoid valve. This valve has flaps that remain in its position when a power failure occurs. Bistable solenoid valves use very little energy.
In general, solenoid valves are sensitive to moisture. It is essential to check the external conditions of the application to choose the right solenoid valves that have sufficient protection class (IP) for the desired environment. You may opt to look for solenoid valves that have lower protection rating so you can install these valves remotely in a less humid area.
Since they are integrated into a circuit directly, solenoid valves are classified using a nominal diameter or DN. The connection and pipe diameters are determined by the standards set for each country or geographical locations where the solenoid valves are going to be utilized, and on the type of media, these valves will be used for.
2/2-way solenoid valves are diaphragm or poppet type valves which are only used for on and off functions since they have no exhaust port. 2/2-way solenoid valves are considered versatile since they are widely used in various applications of several industries.
Mostly considered as a spool type solenoid valve, the 3/2 way solenoid valves means ‘3 ports, 2 positions’ valve. In their resting state, the most basic of 3/2-way valves utilize port 1 as the inlet, port 2 as the valve outlet, and 3 as the exhaust, which is blocked in its resting state.
The spool position changes once the power is applied in the solenoid and the inlet port is blocked while the flow passes through the outlet to the exhaust ports. Normal valve function is restored, and the spool spring goes back to its resting state when there is no power.
5/2-way solenoid valves are quite similar to 3-2 way valves in its operation, except that these valves make use of another two extra ports which are primarily designed to be used as pneumatic cylinders or pilot double acting pneumatic actuators. 5/2-way solenoid valves can be produced with a single coil that allows spring return, or with a double solenoid coil.
5/3-way solenoid valves commonly have two coils. They are considered as a spool type solenoid valve, and these valves have 5 ports and 3 positions. Two of the positions have the same function as those of the 5/2-way solenoid valve. The third position is assigned in a different operation.
The third position is activated when power is not applied in either of the solenoid coils. This position performs the pressure held function or the “all ports blocked function.” Thus, the third position holds the larger actuator and the valve in a steady state until there is power in one of the solenoid coils.
Direct-acting solenoid valves, or also known as direct operated solenoid valves, use an elementary working principle. As the fluid flows through a small hole, called an orifice, the plunger with a rubber gasket on the bottom closes the valve by using a small spring. Made from ferromagnetic materials, the plunger is surrounded by an electric coil to control the operation of the direct-acting solenoid valves using a magnetic field.
The magnetic force pulls the piston to the coil, opening the orifice for the medium to pass through once it is electrically energized. The term for this is a Normally Closed (NC) valve. A Normally Open (NO) valve is operated in the opposite manner. To open the orifice while the solenoid is not energized, the NO valve has been constructed differently. The orifice closes when the solenoid has been actuated.
The maximum pressure and flow rate for the valve’s operation are related to the diameter of the orifice and the magnetic field of the valve directly. Such a principle is widely used for applications having small flow rates. Since direct-acting solenoid valves do not have a minimum operating pressure, they can be used from 0 bar up to the highest pressure rate allowed.
Direct-acting plunger solenoid valves are the most common direct acting solenoid valve, which uses a rugged, effective working principle.
When the coil is de-energized, the core spring, together with the fluid pressure, forces the plunger and the seal which blocks the path from the inlet to the outlet. Once the power is applied, the solenoid coil creates a magnetic force to pull the seal and the plunger upwards and against the fluid pressure and the spring. Thus, opening the path for the fluid to pass through from the inlet to the outlet ports.
Direct-acting 3-way plunger solenoid valves have three ports and two seats. One valve seat is always closed, and the other is always open. Direct acting 3-way plunger solenoid valves are primarily designed to mix and distribute compressed air to pilot larger pneumatically driven valves.
In direct acting 3-way plunger solenoid valves, the spring acts up against the media pressure from under the seat to force the plunger to the valve seat when there is no power in the coil. Once the valves are in their energized state, the plunger is raised up, allowing the fluid to flow through the pressure port and inlet port which then closes the inlet and outlet channel.
Pivoted armature valves boast on their durability, long service life, and user-friendliness. In direct acting pivot solenoid valves, once the valve is switched by the coil, a lateral or rotational movement of the core around the pivot is induced. Thus, allowing the armature to seal one of the two horizontally arranged seats in the body cavity.
Compared to the plunger style, direct acting pivot solenoid valves can be used in a media that separates the diaphragm. These valves can then be used in controlling and regulating corrosive, contaminated fluids, and vacuum.
Direct-acting rocker solenoid valves have very high cycle life, which can be constructed with or without a diaphragm. In these valves, the energy present in the coil flows through a horizontal, low mass rocker moving around a fulcrum between the valve seats to seal one vertically oriented seat.
The operation of direct acting rocker solenoid valves provides enough amount to resist back pressure. In these valves, the ports are all located in the same place where the body is located. When direct acting rocker solenoid valves have no diaphragm, they are used to regulate liquids and neutral gases and are utilized as a pilot for pneumatically actuated valves found in non-hazardous and hazardous environments.
Once a diaphragm is isolated in the direct acting rocker solenoid valves, it separates the valve’s mechanism from the path of the fluid, which allows direct acting rocker solenoid valves to be utilized for aggressive fluids that are employed in either servo-assisted valves, or stand-alone valves.
Direct-acting flipper solenoid valves move in a flexible sealing system which is located in two opposing seats. These valves employ a tremendously high cycle life, which are always integrated with a diaphragm. The vertical framework of these solenoid valves has a flipper with low mass moving around a fulcrum and has a permanent magnet.
Direct-acting flipper solenoid valves are often utilized to control liquids and neutral gases repeatedly. They are being used as a pilot for pneumatically actuated valves in non-hazardous and hazardous environments.
Direct-acting two-way solenoid valves are shut-off valves having one outlet port and one inlet port. When these solenoid valves are de-energized, the core spring uses the pressure of the fluid to hold the valve seat on the valve seat to block the flow of the medium.
The valve opens when it is energized by pulling the seal and core to the solenoid coil. The electromagnetic force present in the entire operation is greater than the combined forces of the spring and static and dynamic pressure of the medium.
Semi-direct operated solenoid valves combine the properties of indirect and direct valves. This combination allows the semi-direct operated solenoid valves to work from zero bar until the maximum pressure rate. These valves are also known for its ability to handle high flow rates. Semi-direct operated solenoid valves have a similar structure with indirect valves. They have a movable membrane with pressure chambers and a small orifice on both sides.
The difference between indirect operated solenoid valves and semi-direct operated solenoid valves is that the solenoid plunger of semi-direct valves is connected to the membrane of the valve. In order for the valve to open, the plunger is lifted to directly lift the membrane creating a passageway for the fluid to pass through.
By lifting the membrane in opening the valve, the plunger also opens the second orifice, which has a larger diameter than the first orifice of the membrane. Pressure drops above the membrane as the second orifice opens. Thus, the pressure difference, aside from the plunger, lifts the membrane upon opening. This combination allows the proper control of systems having relatively large flow rates. Sometimes called as assisted-lift solenoid valves, semi-direct operated valves have more powerful coils compared to indirect operated solenoid valves.
Also known as servo-controlled or pilot operated solenoid valves, indirect operated or indirect acting solenoid valves utilize the pressure difference of the fluid throughout the ports to close and open the valve. The minimum pressure difference of indirect operated solenoid valves is about 0.5 bar.
A rubber membrane, known as the diaphragm, separates the inlet port and outlet port of these valves. The diaphragm has a small orifice that allows the medium to flow through the upper compartment of the valve. The pressure from the fluid flow and the spring located above the diaphragm prevents the valve from opening. When the valve is closed, the solenoid blocks the low-pressure port, which is connected to the chamber above the diaphragm.
The pilot orifice has a larger diameter compared to the hole found in the rubber membrane. In its energized state, the solenoid, the orifice opens, causing a pressure drop from the upper part of the membrane. The differential pressure present on the two sides of the diaphragm lifts the membrane allowing the fluid to flow from the inlet port up to the outlet port.
A small solenoid can control a large flow rate because of an extra pressure chamber found in the diaphragm that functions as an amplifier. Indirect operated solenoid valves are used for operations requiring one flow direction only. These valves are mostly utilized in applications having a sufficient pressure difference and a highly desired flow rate. Irrigation systems, car wash systems, and showers make use of indirect operated solenoid valves.
Internally piloted solenoid valves are employed to switch higher pressures with larger orifice sizes. The differential fluid pressure in these valves is responsible for opening and closing the valve.
Internally piloted 2-way solenoid valves use a diaphragm to provide sealing for the main valve seat. Once the pilot valve is closed, the fluid pressure increases on both sides of the diaphragm and builds up through a blood orifice. A shut-off force is available above the diaphragm when the pressure difference is still present between inlet and outlet ports.
During the pilot valve opening, the diaphragm releases the pressure that is present in the upper compartment of the membrane. The valve opens when a greater net pressure force lifts the diaphragm to allow fluid flow. Generally speaking, internally piloted valves need a minimum pressure difference to completely open and close the valve.
Internally piloted 4-way solenoid valves are primarily designed for pneumatic and hydraulic circuits to actuate double-acting cylinders properly. Four port connections – a pressure inlet, one exhaust port connection, and two cylinder port connections – are present in these valves.
The pilot valve opens in the de-energized state from the pressure inlet to the pilot channel connections. Both poppets present in the main valve have been switched over and pressurized. The pressure inlet will then be connected to one of the cylinder port connections, while the remaining cylinder port connection can release the medium via a second restrictor through the exhaust port connection.
Externally piloted solenoid valves are actuated by an independent pilot medium. The valve seat remains closed when the environment is unpressurized. A 3-way solenoid valve can be mounted on the actuator to control the independent pilot medium.
When the valve is energized, the plunger is lifted against the spring, which then opens the valve. The independent pilot medium is connected to the top of the actuator. Double-acting versions of externally piloted solenoid valves controlled by 4/2-way valves have no spring attached.
Two-way solenoid valves are the most common type of solenoid valves. These valves have two ports which will allow or block the fluid to pass through to “normally open” or “normally closed” the valve.
A normally open valve remains open until a current has been applied for the valve to close. The valve automatically returns to its normal state when there is a suspension in the electrical power. A normally closed solenoid valve will only open once a power source initiates the opening of the valve.
Three-way solenoid valves have three ports. These valves are commonly found in applications where other or exhaustive pressure are necessary for the operation, such as dishwasher or coffee.
Three-way solenoid valves are used in applications having single-acting actuators, such as diaphragm actuators. Three-way solenoids are used to send air from a single chamber of an actuator. Three-way solenoids interrupt the instrument signal for double-acting actuators having a pneumatic positioner.
3-way normally open solenoid valves have 3 pipe connections: the body orifice port, the stop port, and the cavity port. These valves have two orifices which are the body orifice and the stop orifice. One of the two orifices is always open to allow two paths of fluid flow.
When there is no power, the plunger is lifted to seal off the stop orifice which opens the body orifice to enable the fluid to pass through the valve from the body orifice port to the cavity port. Once the coil is in its energized state, the plunger is down which opens up the stop orifice to enable the fluid to flow through the valve from the cavity port to the stop port.
Similar to 3-way normally open solenoid valves, 3-way normally closed solenoid valves have three pipe connections and two orifices, which enables two paths of flow. When the coil is de-energized, the plunger moves down sealing off the body orifice to open the stop orifice and allow the fluid to pass through the valve from the cavity port and out to the stop port.
When the power is activated, the plunger is lifted, which opens the body orifice to allow the fluid to flow throughout the valve up to the stop port.
3-way directional control solenoid valves have two orifices and three pipe connections. When the valve is energized, it lowers or raises the plunger. By lifting the plunger, the body orifice opens up to direct the flow of the fluid throughout the body of the valve. When the plunger is down, stop orifice opens to allow the fluid flow to pass through the stop port.
Four-way solenoid valves have four or more port connections. Four-way solenoid valves are used with an actuator or a dual-acting cylinder. Half of the port connections in these valves supply pressure, while the other connections provide exhaust pressure. Four-way solenoid valves can be specified as normally open, normally closed, or universal.
Four-way solenoid valves have positive bi-directional action. Instead of using positioners, four-way solenoids can control the on-off operation of double-acting valves. When the solenoid is in a de-energized state, the air supply is delivered on one side of the actuator and exhausted on the other side.
Once the system starts operating, the electric motor controls the compressor, which absorbs filtered air. The air is then compressed and transferred to the refrigerator to reach the tank. In this stage, power passes through the solenoid valve through the electric coil to energize the valve. The operation closes the circuit to regulate the pressure in the valve.
As soon as the tank achieves the desired pressure reading, the motor is then stopped by a pressure switch, which keeps the air intact inside the tank. To avoid the compressor from being damaged by prolonged exposure to pressure, the solenoid valve opens, and the power ceases. Once this is done, the air in the circuit is released through an exhaust port.
Two three-way solenoid valves are used in this application. When solenoid valves are de-energized, the pressure inlet connected from the cylinder port to the exhaust port is closed. Pressure gauges compound pressure to control the amount of pressure in the pipes.
An electronic panel regulates two solenoid valves all at the same time. Solenoid valves used as press safety valves allows the fluid to flow through the valve to the piston chambers by closing their own exhaust ports. The pressure during this operation drops to enable the fluid from passing through the pressure inlet to the cylinder port connection.
In the simulation of a failure, the coil should be de-energized to reduce pressure which causes the spring to lift the piston upward and the exhaust to be opened. The fluid moves from the pressure inlet to the exhaust port, which blocks the valve. Once the system is safe, the valve can operate again and automatically resets when the stand-by position is restored.
A circular vibrator is composed of a vibrating base, a separate electronic controller to set the excursion of the vibration, and a container which can be in a stepped, conical, or cylindrical shape. A container has a spiral guider found in the internal wall to permit small parts in ascending to the linear feeder.
The pulsating force in the container is due to a magnet, which is also responsible for the vibrations produced. These vibrations cause the small parts to move forward along a track found in the container. At the end of the track, a series of traps are present to choose parts placed in a wrong position. These small parts fall at the center of the painter to make sure that only the parts in the correct position will pass through.
The solenoid valve prevents compressed air from entering the system. Instead, the valve leads the fluid to the small parts to push them into the assembly machine.
A photocell is located at the mouth of the feeder. The de-energized solenoid valve blocks the flow of air in the system once a failure is detected, causing the vibrator to stop functioning. The only way to reset the process is the intervention of an operator.
Dental chairs are equipped with all the necessary dental tools and adjustable lamp. They have automatic functions controlled by a console that the operator can easily use. The chair is lifted through a system by a hydraulic cylinder which utilizes oil as the medium. The height of the chair is regulated by two solenoid valves.
From the basin, the medium is pumped to the circuit at a pressure of 12-13 bar. The solenoid valves are operated by the buttons of the console. These valves prevent oil from entering into the pump and instead pushes medium flow through the cylinder.
The cylinder is responsible for the conversion of hydraulic energy to mechanical energy which is done every time the chair is lifted to its desired height. To open the second valve, another button should be pressed. Because of the overhanging weight, the medium inside the cylinder is released into the basin.
Source: GEM Vending
Found in public areas, private facilities, and offices, hot drink dispensers provide coffee, tea, and other hot drinks instantly to people. Vending machines, aside from coffee, provide soluble beverages quickly, which are widely used in various establishments.
Vending machines are divided into two types of supply. First is for coffee, and the other one is for soluble beverages. In this article, however, we will discuss more the operation of supplying soluble beverages, specifically the use of solenoid valves with media at atmospheric pressure.
The sequence of distribution is as follows: First, the glass is placed in the right position. Then the sugar is supplied, and the coffee spoon and beverage is provided afterward.
As the user chooses the product by pushing an electronic button, the infusion process is activated. A volumetric dispenser prepares a single dose of powder into the mixer. The solenoid valve delivers the hot water at 90-95 degrees from the boiler to the mixer. By letting in fresh water into the electronic system, the level of water inside the boiler remains constant.
In coffee-in-cartridge dispensers, two three-way solenoid valves prevent the flow of water from passing through the vibrating pump, which is responsible for providing supply for the hydraulic actuator. The tank, on the other hand, brings water to the boiler, which contains hot water and a thermostat to regulate the temperature.
Once the cartridge is in, the actuator pushes the boiler against the cartridge, and the solenoid valves are open. Before the actuator goes down completely, a safety valve on top of the second solenoid valve blocks the fluid from flowing.
Once the pressure reaches 9-10 bar for about 10 seconds, cold water is released by the safety valve as it opens to pass through the boiler. The release of cold water occurs once the previously warm water is filtered through the cartridge. The mixture produced, i.e., coffee or chocolate goes into the cup through a nozzle.
The second solenoid valve starts to close, and the remaining fluid from overpressure is exhausted into the tank at the end of the cycle. The first solenoid valve also closes and releases the water from the actuator into the tank. Because of the spring force, the actuator returns into its resting state.
Integrated industrial ironing boards are used for the final finishing of cloth. The appliance is composed of a vacuum blow table, an iron, and a sleeve form board. Utility presses, spotting tables, and ironing boards are categorically known as an ironing group for various operators.
Each machine can be connected to steam, a compressed air set, or vacuum, or can be operated alone. For an efficient process in ironing the clothing, the system uses steam in operation. To supply steam, the iron has a push-button control to release the medium when pressed. The solenoid valve found in the ironing board takes control of the steam that an electric boiler has released once the operator presses the button control.
In industrial ironing boards, the solenoid valve has a flow regulator in the form of a knob or screw to allow the operator to regulate properly the quantity and pressure of the steam needed to iron the garment. Solenoid valves that can withstand demanding applications and high pressure levels are best suitable for this application.
Self-service car washing systems are considered an innovation in the car washing industry. These systems are washing areas for cleaning and polishing vehicles such as camper vans, scooters, small boats, caravans, motorcycles, and all-terrain vehicles that traditional car washing systems cannot clean.
In a car washing system, high-pressure water with a mixture of detergent, wax, and car washing form is delivered through a brush and a lance. The user decides on the cleaning cycle by selecting one on the control panel. Two necessary tools are needed in cleaning the vehicle: a lance and a brush.
Solenoid valves are used in the circuit to interrupt the flow of the liquid detergent. Once the electromechanical pump sucks the liquid detergent to deliver it back to the circuit at 80 bar, the liquid mixes with air before reaching the brush.
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