The solenoid valve is modern look shut-off valves, installed on heating pipelines, water supply, land reclamation, technical water pipelines at industrial enterprises. The device is based on an electromagnetic coil - a solenoid, which receives an impulse from external device(sensor or controller) and blocks or opens the flow of the working environment.
The main principle and advantage of using this device is automation. The valve was designed to shut off the flow of water or other liquid/gas when certain system parameters—temperature, pressure, speed, and flow—change without human intervention. This happens due to electrical magnetic field in the area of action of the valve core (plunger). When voltage occurs, it lowers or rises, depending on the conditions provided.
The working energy that drives the plunger is generated by the movement of electrons along the copper winding of the coil. The magnetism that appears when a pulse is applied from an external device is converted into a translational movement that lowers the plunger. The latter blocks the flow of water, allowing you to avoid large technological losses. As soon as the situation returns to normal, the tension disappears and the plunger rises, allowing water to continue moving through the pipes.
Important! Another advantage of the solenoid valve is high speed triggering. Thanks to this, the device can shut off the flow of water in the event of an accident on a pipeline section within 2-3 seconds after the sensor is triggered. Due to this, valves are indispensable in heating systems, hot and cold water supply, and in technical pipelines at industrial enterprises.
Design features
The valve device consists of a polymer or metal body, inside of which there is a solenoid, plunger, rod and membrane.
The material for the body is plastic, or stainless steel, brass or cast iron, which is determined by the scope of use of the valve. For example, a metal housing is used in systems with chemically aggressive or high-temperature environments, while plastic ones are used for simple drinking water or technical fresh water. Diaphragms and valve seals are made from polymer materials based on rubber and polyethylene.
This article will focus on solenoids. First, let's consider the theoretical side of this topic, then the practical side, where we will note the areas of application of solenoids in various modes their work.
A solenoid is a cylindrical winding whose length is significantly greater than its diameter. The word solenoid itself is formed by a combination of two words - solen and eidos, the first of which is translated as pipe, the second - similar. That is, the solenoid is a coil shaped like a pipe.
Solenoids, in a broad sense, are inductors wound with a conductor on a cylindrical frame, which can be either single-layer or multi-layer. Since the winding length of the solenoid greatly exceeds its diameter, when feeding DC through such a winding, inside it, in the internal cavity, an almost uniform magnetic field is formed.
Some are often called solenoids. actuators, electromechanical principle of operation, such as the solenoid valve of an automatic transmission of a car or the starter solenoid relay. As a rule, the retracted part is a ferromagnetic core, and the solenoid itself is a so-called ferromagnetic yoke.
If there is no magnetic material in the solenoid design, then when direct current flows through the conductor, a magnetic field is formed along the axis of the coil, the induction of which is numerically equal to:
Where, N is the number of turns in the solenoid, l is the winding length of the solenoid, I is the current in the solenoid, μ0 is the magnetic permeability of the vacuum.
At the edges of the solenoid, the magnetic induction is half as much as inside it, since both halves of the solenoid at the point of their union make an equal contribution to the magnetic field created by the solenoid current. This can be said about a semi-infinite solenoid or about a coil that is quite long in relation to the diameter of the frame. The magnetic induction at the edges will be equal to:
Since the solenoid is primarily an inductance coil, then, like any coil with inductance, the solenoid is capable of storing energy in a magnetic field, numerically equal to work, which the source performs to create a current in the winding that generates the magnetic field of the solenoid:
A change in the current in the winding will lead to the appearance of a self-induction EMF, and the voltage at the edges of the wire of the solenoid winding will be equal to:
The inductance of the solenoid will be equal to:
Where, V is the volume of the solenoid, z is the length of the wire in the solenoid winding, n is the number of turns per unit length of the solenoid, l is the length of the solenoid, μ0 is the magnetic permeability of the vacuum.
When passing alternating current through the solenoid wire, the magnetic field of the solenoid will also be alternating. The solenoid's resistance to alternating current is complex and includes both active and reactive components, determined by the inductance and active resistance of the winding wire.
Practical use of solenoids
Solenoids are used in many industries and in many areas of civil activity. Often linear electric drives are just an example of the operation of solenoids on direct current. Scissors cutting checks in cash registers, engine valves, starter traction relay, valves hydraulic systems etc. On alternating current, solenoids work as inductors.
Solenoid windings, as a rule, are made of copper, less often - of aluminum wire. In high-tech industries, windings made of superconductors are used. The cores can be iron, cast iron, ferrite or other alloys, often in the form of a package of sheets, or they may be completely absent.
Depending on the purpose electric machine, the core is made of one material or another. Devices such as lifting electromagnets, seed sorters, coal purifiers, etc. Next, we will consider several examples of the use of solenoids.
As long as voltage is not applied to the solenoid winding, the valve disc is pressed tightly against the pilot hole by the spring, and the pipeline is shut off. When current is applied to the valve winding, the armature and the valve plate connected to it rise, being drawn in by the coil, counteracting the spring, and opening the pilot hole.
Pressure difference with different sides from the valve leads to the movement of liquid in the pipeline, and as long as voltage is applied to the valve coil, the pipeline is not blocked.
When power is removed from the solenoid, there is no longer anything holding the spring, and the valve poppet rushes down, blocking the pilot hole. The pipeline is blocked again.
The starter is essentially a powerful DC motor powered by the car's battery. When the engine starts, the starter gear (Bendix) must quickly engage the crankshaft flywheel for a while, and at the same time the starter motor turns on. The solenoid here is the coil of the starter solenoid relay.
The retractor relay is mounted on the starter housing, and when power is applied to the relay winding, an iron core connected to a mechanism that pushes the gear forward is retracted. After the engine starts, the power is removed from the relay winding and the gear returns back thanks to the spring.
In solenoid electric locks, the bolt is driven by the force of an electromagnet. Such locks are used in access control systems and in sluice door systems. A door equipped with such a lock can only be opened while the control signal is active. After this signal is removed closed door will remain locked regardless of whether it was opened.
The advantages of solenoid locks include their design - it is much simpler than that of motor locks and more wear-resistant. As you can see, here the solenoid again works in tandem with the return spring.
For through heating, solenoid multi-turn inductors are usually used. The inductor winding is made of a water-cooled copper tube or a copper busbar.
In medium frequency installations, single-layer windings are used, and in industrial frequency installations, the winding can be either single-layer or multi-layer. This is due to a possible decrease electrical losses in the inductor and with the conditions for matching the load parameters and with the parameters of the power source in terms of voltage and power factor. To ensure the rigidity of the inductor coil, it is most often used to tie it between the end asbestos-cement slabs.
IN modern installations solenoids operate in AC power mode high frequency, therefore, as a rule, they do not need a ferromagnetic core.
In single-coil solenoid motors, turning the operating coil on and off leads to mechanical movement of the crank mechanism, and the return is again carried out by a spring, similar to what happens in the solenoid valve and in the solenoid lock.
In multi-coil solenoid motors, the coils are switched on alternately using valves. Current from the power source is supplied to each coil in one of the half-cycles of the sinusoidal voltage. The core is alternately drawn in by one or the other coil, performing a reciprocating motion, driving the crankshaft or wheel into rotation.
Experimental facilities such as the ATLAS detector, operating at the Large Hadron Collider at CERN, use powerful electromagnets, which also include solenoids. Experiments in particle physics are conducted to discover the building blocks of matter and study the fundamental forces of nature that support our universe.
Finally, connoisseurs of Nikola Tesla's legacy always use solenoids to build coils. The secondary winding of a Tesla transformer is nothing more than a solenoid. And the length of the wire in the coil turns out to be very important, because coil builders use solenoids here not as electromagnets, but as waveguides, as resonators, in which, as in any oscillatory circuit, there is not only the inductance of the wire, but also the capacitance formed in in this case coils located close to each other. By the way, the toroid on top of the secondary winding is designed to compensate for this distributed capacitance.
We hope that our article was useful to you, and now you know what a solenoid is and how many areas of its application there are in modern world, because we have not listed all of them.
For water, it is designed to regulate the passage of liquid. The device operates on an electromechanical principle. For the manufacture of the body, resistant and universal, as well as high-strength materials such as cast iron, brass, stainless steel. As for membranes and seals, they are made of highly elastic polymers. Among other things, the composition may contain silicone rubber.
Such a device is installed in that part of the pipeline system to which easy access will be provided.
Solenoid valve design
Also called solenoid. It consists of main parts such as a membrane, housing, spring, cover, rod, and also a solenoid. The valve cover and body are cast from stainless steel, brass, polymers or cast iron. These devices are designed for operation in a wide range of operating environments, temperatures and pressures.
Magnetic materials are used for rods and plungers. Electric coils, called solenoids, are manufactured in a dust-proof or sealed housing. High-quality enamel wire is used for winding the coils. It is made of electrical copper. The connection to the pipeline system can be made using the slate or threaded method. To connect to electrical network plug is used. Control is carried out by applying voltage to the coil.
Leading working positions
If we consider the above-described devices according to their design, they can be normally closed or normally open. Among the varieties, we can also distinguish bistable valves, which are called pulse valves. The control principle facilitates switching from closed to open position.
Operating principle
Can be used for different conditions, this involves the use of devices direct action, as well as devices that operate at zero pressure drop. On sale you can find indirect-acting valves that are pilot valves. They operate exclusively at the smallest pressure drop.
Such devices can be divided into three-way distribution, shut-off and switching valves.
Information about seals and membranes
The solenoid valve for water contains membranes that can be made of elastic polymer materials. The latter have a special design and chemical composition. Among other things, the latest compositions and other polymers are used in the design of the valves.
Operating principle of pilot valve
A solenoid valve for water can be installed quite quickly with your own hands. If we're talking about about a normally closed device, then in the static position there is no voltage, while the valve is in the closed state. The piston, which is a shut-off organ, is pressed hermetically; it is located at the seat of the sealing surface. The pilot channel is in a closed state. The pressure in the upper cavity is maintained using a bypass hole in the membrane.
This type of valve remains closed until the coil is stressed. In order for it to open, voltage must be applied to the coil. Under the influence of a magnetic field, the plunger rises, opening the channel. Due to the fact that the diameter of the channel is much larger than the bypass, the pressure of the upper cavity decreases. The pressure difference causes the piston or diaphragm to rise, causing the valve to open. The water supply solenoid valve will remain open as long as the coil is energized.
Operating principle of a normally open valve
This device works by the opposite principle: in a static position the device is in open form, but when the voltage increases, the valve closes. In order to keep the device closed, voltage will be supplied to the coil for a long time. In order for any pilot valves to operate properly, a low pressure drop must be maintained.
Such devices are called indirectly acting valves for the reason that in addition to supplying voltage, a condition must be met, which is a pressure difference. This device can be used for heating systems, water supply, hot water supply, as well as pneumatic control. The unit is suitable for conditions where there is pressure in the pipeline.
Direct acting valve operation
An electromagnetic valve, the diagram of which makes it possible to understand the principle of operation, can have direct action. This device does not have a pilot channel. In the central part there is an elastic membrane that has a metal ring. It is connected to the plunger through the spring. When a magnetic field is applied to the coil, the valve opens, the plunger rises and relieves the force on the membrane. The latter rises and helps open the valve. At the moment when closing occurs, there is no magnetic field, the plunger lowers and acts on the membrane.
For such a device, a minimum pressure drop is not required. The solenoid valve, a photo of which is presented in the article, can be used in pressure systems, as well as on drain tanks. The device can also be installed in storage receivers. Such a device can be installed in places where there is no pressure or is at a minimum level.
Features of the bistable valve
This valve can be in two stable positions: closed and open. Switching is carried out sequentially by applying a pulse to the coil. Such devices operate exclusively from a direct current source. To keep the valve closed or open position, no voltage required. By design, such devices are made as pilot ones, this indicates the need for a minimum pressure drop.
The solenoid valve is a reliable and functional fitting for the piping system. If we are talking about special electromagnetic coils, then their service life is very long. Until the device fails, it can operate until the number of starts reaches 1 million. The time it takes for the magnetic valve to operate can range from 30 to 500 milliseconds. The final figure will depend on the pressure, diameter and design.
Conclusion
Device solenoid valve was presented above, as well as the principle of its operation. Such devices can be used as locking device remote control. They are indispensable for safety as shut-off, shut-off and switching electric valves. These features must be taken into account before purchasing a valve and installing it in certain conditions.
are electromechanical control devices used to control and control the flow of various media, such as water or gas, as well as many others. It is called a solenoid valve because an electromagnetic coil (solenoid) is used to activate the control device.
How does a solenoid valve work?
When there is a need to block the flow of the medium (closing the valve), the control device supplies the electromagnetic coil with electrical voltage. Under the influence of electricity, the core lowers (or rises, depending on the design of the valve), and blocks the flow of the medium. When the voltage disappears, the core returns to its original state.
What are the advantages and disadvantages of a solenoid valve?
Application of solenoid valves.
Solenoid valves are used in various industries. They are used in mechanical engineering, chemical and oil and gas industries, cleaning systems, refrigeration equipment, central heating, systems automatic fire extinguishing and many other areas
Types of solenoid valves and their operating mechanisms
Depending on the state of the valve before voltage is applied to it, valves are divided into normally closed valves and normally open valves. Normally closed valves are closed when not in use, but open when voltage is applied. Normally open valves are open when operating and close when voltage is applied.
Depending on the degree of impact on the flow, valves can be shut-off valves - they are used when instantaneous shutdown of the flow is necessary, for example, in the event of a possible accident, and regulating valves - they are designed to gradually change the flow power, as well as for mixing them
According to the method of connection to the pipeline, the valves can be coupling valves (attached using threaded connection), flanged (using flanges), wafer (the valve is located between flanges, tightened with special pins) and welded (connection is carried out using electric welding)
According to the nature of action, valves are one-way, two-way, three-way, and four-way,
There are also two mechanisms for the operation of such valves:
- Direct action, used at low flow rates - that is, adjustment occurs exclusively when voltage is applied to the coil and the core is set in motion;
- Pilot action, used at high flow rates - the supply of voltage acts on the pilot, and the opening of the main valve occurs by using the energy of the water flow. This operating mechanism requires a pressure drop of about 0.2 atm. This is the principle that electromagnetic check valve for water, preventing backflow in the pipeline.
What materials are used in solenoid valves?
Solenoid valves are used in the most different combinations equipment, including for monitoring highly aggressive environments. The valve body must be made of high-strength material to prevent premature failure. The most important components here are the sealing materials.
How to choose a valve seal?
Seal selection is the most difficult aspect of solenoid valve selection. Here you need to take into account chemical properties environment, temperature and pressure. The most common sealing materials are Nitrile butadiene rubber (NBR), ethylene propylene rubber (EPDM), fluorine rubber VITON And polytetrafluoroethylene (PTFE).
Valve Seal Materials
| Material | Most Common Environments | Good resistance | Poor resistance |
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| NBR |
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| EPDM |
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| Viton |
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How solenoid valves work (video)
Regional gas company"Palyur" is official dealer Belarusian manufacturing enterprise"Thermobrest.
We supply Vn and VF solenoid valves, as well as other shut-off valves produced by the company. The list of products can be viewed at the link:
An electromagnetic valve, or solenoid valve as it is also called, is a type of shut-off valve with an electromechanical operating principle. It performs the functions of automation and remote control of the direction of gaseous and liquid working media on the pipeline. Metered supply of the required volume of flow at a time is ensured using an electromagnetic coil.
The solenoid valve is widely used both at the domestic level and in large industrial systems. Over a wide range of operating temperatures. The electromagnetic valve regulates the flow of the medium. , .
Operating principle and design of solenoid valve
In the production of the solenoid valve, materials are used that meet the requirements of GOST and international standards. The solenoid valve consists of the following elements:
In this case, the body can be made of,. is placed in a sealed housing, and the winding is made of high-strength technical copper. To ensure maximum tightness, materials such as heat-resistant rubber, silicone, rubber, fluoroplastic, and polytetrafluoroethylene (PTFE) are used for manufacturing. Stainless steel is also used for production.
The operating principle of the solenoid valve is based on the operation of an element such as an electromagnetic coil. When permanent or AC is missing on the reel, then under mechanical impact the springs, diaphragm or valve piston are located in the seat of the device. However, when voltage of varying power is applied to the solenoid, the plunger is pulled into the coil, thereby opening or closing the flow hole. Stopping the voltage supply to the coil causes the valves to close. Solenoid valve may have different design features which depend on its type.
Types of Solenoid Valve
Solenoid valves are divided according to the type of operating position, operating principle, connection to the pipeline, sealing membrane and piston seal.
According to the type of operating position, valves are:
· Failure of the induction coil is caused by incorrect voltage power supplied to the coil or by exceeding the temperature or pressure limits inside the pipeline, and moisture entering the coil can also cause short circuit and coil combustion. This fault can be corrected by replacement. You can also set to prevent the coil from overheating.
· If the valve does not open and close completely, this may be caused by a clogged control hole, a defect in the diaphragm, gasket or piston seal, as well as residual voltage on the coil.
Solenoid valve repair is carried out by qualified specialists who have access to work with electrical networks.
Production of solenoid valves carried out in special factories pipeline fittings, which are located in almost every country in the world.
Solenoid Valve Cost depends on its functions, type of design, diameter, company manufacturer of electromagnetic (solenoid) valves. Our specialists can help determine required type devices.