Homemade solenoid valve. Do-it-yourself electromagnetic valve for irrigation

A solenoid valve for water is a widely used electromechanical device that regulates the flow of liquids and gases through a pipeline.

The design of the valve is quite simple:

valve body and covers. For their manufacture, brass, stainless steel, cast iron or a variety of polymers (ecolon, polypropylene, nylon, and others) can be used.

Valves (24 VAC solenoid and valve itself) operating at all pressures and temperatures. Due to the use of modern materials in their design, they are quite resistant to aggressive environments.

Plungers and rods are made of special magnetic materials.

Solenoids (electric coils) are enclosed in a sealed housing, which serves as a reliable protection against dust. The winding is done with high quality enamel wire made of electrotechnical copper.

Operating principle

The electromechanical water valve is designed in such a way that in the event of a power outage or failure of the control panel, it can be used like a regular water tap.

To do this, it is enough to turn the control solenoid a quarter of a turn in the direction indicated by the arrow:

ON - open
OF - closed.

In addition, manual control allows you to quickly preserve the irrigation system for the winter period.

Connection

The valve is connected to the mains by means of a plug. It is controlled by applying a pulse (voltage) to the solenoid. The supply voltage can be:

AC (AC: 24V, 110V, 220V);
direct current (DC: 12 V, 24 V).

The main operating position of the solenoid valve depends on its design:

normally open (NO);
normally closed (NC);
pulse (bistable) - the most common and switching from one position to another by a control pulse.

The solenoid valve for supplying and relieving water pressure is widely used in automatic irrigation systems and performs the function of an electric faucet.

At the right time, it opens through the control panel and passes the necessary flow of water into the irrigation pipeline.

Choice

The range of models of manufactured valves is very extensive, but they all meet the main requirement - to give water access to the irrigation system. The main parameter when choosing a device is the size of its inlet and outlet (1-3 inches).

All manufactured models can have only design features that do not affect the performance of the valve.

However, the most popular are 1-inch solenoid valves with high throughput: up to 50 l / min, installed both on long pipelines (HDPE 80 with a diameter of up to 40 mm) and on short watering lines, but with a large water flow.

A positive feature of the solenoid valve is a built-in mechanical regulator that regulates the water level in the irrigation system.

Thus, optimal water flow is achieved, it becomes possible to more accurately adjust the irrigation radius using sprayers, and the valve becomes an integral part of drip irrigation, that is, it is used in low-pressure systems.

The most popular are normally closed inch valves of the SRV series with a capacity of more than 100 l / min and an operating pressure range of 1.5 - 10 atm.

For safety reasons, a valve with an inlet larger than 1 inch must be fitted with a water pressure regulator.

Installation and causes of failure

An electric valve for lowering and increasing water pressure is installed on a crushed stone drainage pad near the irrigation system, after which it is covered with a box.

Its close location to the pipeline allows you to save money and maintain the operating pressure in the irrigation system.

Any, even the most reliable equipment, during its operation, can suddenly fail. The solenoid valve for water is no exception.

Breakdowns can occur for several reasons:

Cable break from the control panel - voltage does not reach the valve.

Plunger spring broken (replace solenoid) - valve does not operate with normal power supply.

The solenoid coil burned out. In this case, there is no click when turned on.

Blockage of the hole on which the solenoid is wound is clogged. It is necessary to unwind the structure and flush the hole.

Where is it applied?

The scope of the solenoid valve, in addition to its use in the irrigation system, is very extensive:

The industrial use of the solenoid valve for water is:

Firstly, in its installation in the automation system for washing water treatment lines (industrial reverse osmosis). Here, valves with a sufficiently high pressure are used - up to 70 atm.

Their second purpose is to automatically maintain the required level in the tanks, as well as distribute and mix various flows.

Electric valves are needed for automatic control of various hydraulic systems. Finished products are quite expensive. Let's look for a cheaper solution.

The most accessible valves are from failed washing machines.

The coils of such devices are designed for a voltage of 220 volts AC, which limits their capabilities. Sometimes it is more convenient to control the valve with a low voltage of 12 volts.

I needed such a device to regulate the mode of the heater of the passenger compartment of a VAZ car. Suitable valves from foreign cars are outrageously expensive, and with the appreciation of the currency they become a luxury item. Let's try to convert the solenoid valve from the washing machine to the on-board voltage of the car.

First, let's see how it all works.

We remove the coil by inserting a thin screwdriver into the gap between the solenoid and the housing. In this case, you can slightly compress the petals that fix the solenoid coil with pliers.

To operate at 12 volts, the valve solenoid (coil) must be replaced.

The most suitable solenoid was found in the EPPKh VAZ 2105 air valve.

Since no images of the insides were found on the Internet, I will give them for the curious.

Let's start disassembly

The simplest thing is to cut off the rolling on the emery or cut it with a file along the outer edge.
Valve cover (inside view):

Stock, he's a cork. The air flow is blocked by a rubber insert at the end. On the opposite end there is a recess for the spring:

Steel washer to close the magnetic flux and non-magnetic guide in which the stem moves:

Coil:
1. In the case.

2. Taken out.

Oval o-rings seal the leads from the inside of the housing. We will need one of them in the future, so save them.

And finally, the case from the inside. The end face of the fixed magnetic circuit with a protrusion for the spring is visible:

The next step is to refine the hull. On the sandpaper, we grind the tube with a riveting from the back side, and putting the case upside down, gently knock out the remnants of the internal magnetic circuit with a beard. If the body is washed inward, we eliminate the deformation. Next, the central hole is drilled to a diameter of 9mm.

To create a magnetic system similar to the valve system from a washing machine, it is necessary to cut two strips from tin from a can - one 15 mm wide, the other 10 mm wide. The length of the strips should be such that a ring of about 1.5 turns is wound on the valve stem from the washing machine.

Summer is the most successful season for innocent water fun in the country and surrounding areas. Why at cottages? Because, I would not use this valve at home. What are we talking about?
Let's try to figure it out.
And so, let's get started!

In fact, this part of automation is still completely unexplored for me,
However, I would like to find a budget option for experiments. Fortunately, there is a dacha and often, for certain reasons, the possibility of my presence on it does not coincide with the desired schedule for the distribution of water ... What exactly is this for?
There are a lot of options - automatically distribute water to certain areas of the dacha, automatically pour an additional container (because the water supply is limited in time, and the water pressure does not allow you to do everything at once).

Thread 1/2, there is no outer casing, the coil is cast, there is a metal mesh at the inlet to the valve, on the body there is a water supply arrow (inlet-outlet), the principle of operation is a membrane, which closes the valve under the action of a spring. The valve is normally closed.

The seller sends with a track that is absolutely not tracked.

Seller details:

Data from the device:

I want to say right away that the seller's data does not match reality, although the data on the nameplate are more reliable (except for zero pressure).

Firstly, and this is the most important factor - for systems with low pressure, the valve WILL NOT work! He needs support to open the membrane.
Secondly, the current consumed by the coil is 2! (TWO) times more - 430 mA, and during prolonged operation, it heats up significantly. True, the valve begins to open at about 7-8 V.

Now let's start preparing the patient:

We unscrew 4 screws and see: a whole molded plastic frame, a rubber valve, a cylindrical flask in which there is a metal core and a spring supporting the valve in a closed state. On the left in the photo - the entrance of water, on the right - the exit.
As you can see, there is a risk of leakage and there is a risk of failure due to the core and spring not being protected from rust.

PROS: simple design, low cost.
CONS: plastic thread and body, high current consumption, no additional sealant other than a rubber membrane, inability to use in systems with low pressure.

It remains to test it in combat conditions.

I plan to buy +39 Add to favorites Liked the review +25 +55

Any electrical machine works due to the presence of many special parts. We offer to consider what a normally closed solenoid valve is, its principle of operation and where to buy it.

General information

The electromagnetic solenoid water or gas valve is an electromechanical device designed to control the flow of liquid or gas in appliances with a power up to v308 (EV220B, Tecofi, Castel, ESM, EVR, GBP, GBV, NBR, PARKER, SCE, SYDZ, automatic transmission, KSVM, ZSK, ISP, Burkert, KSP). This valve is controlled by an electric current that passes through the coil. When current is applied, a magnetic field is created and causes the piston inside the coil to move. Depending on the design, the piston will open when electricity is applied, or the flow valve will close. When the current stops flowing to the valve coil, it will return to its normal state.

Photo - Danfoss solenoid valve

Mechanisms are:

direct and indirect type of action;
vacuum, hydraulic, pneumatic valve;
2-, 3-, multi-way.

Direct acting electric valves open and close an orifice inside the valve. In experimentally controlled valves (they are also called shut-off devices), the piston opens and closes the hole. High pressure valves (such as a flanged valve) use pistons and special seals to control the state of the orifice.

Video: Danfoss solenoid valves

Description of the construction of the standard device

The simplest solenoid valve has two ports: inlet and outlet. Additionally, there may be three or more ports.

Photo - Solenoid valve design

Water or gas enters through the inlet (2). Any substance must pass through the tank opening (9) before entering the outlet (3). The outlet is closed by a piston (7).

The solenoid valve in the photo above is a normally closed solenoid valve type ASCO, TORK or Danfoss. It works as follows: these devices are connected to a spring (8), which presses on the piston against the opening of the bore. The sealing material at the tip of the piston contains a protection (gasket) against water or gas entering the holes, as long as the piston is lifted by the electromagnetic field generated by the coil. The diagram demonstrates the operation of the standard.

Photo - Solenoid valve

There are many valve design variations. Conventional valves may have multiple ports and pistons. The two-way valve of indirect action (return) has 2 ports - EV1140, DU50, DU32, DU100, DU15, DU25, RU16 series; if the valve is open, two ports are connected and liquid moves between them; if the valve is closed, the ports are isolated. If the valve is open, then the solenoid is not energized, then the valve is called normally open (NO). Similarly, if the valve is closed, then the solenoid is not energized, such a valve is called normally closed, say, YCD21, YCPS31, YCWS1. There are also three port and more complex device designs, their designation looks like 30 (3, 33, etc.). The three-way valve has 3 ports for motor control; it connects one port or two of them (usually an intake port and an exhaust port).

A small solenoid valve can generate limited force. The approximate relationship between the required electromagnetic forces Fs, fluid pressure P and orifice area A for a direct acting valve is:

Fs \u003d P * A \u003d P * pi * d 2 / 4

Where d is the hole diameter.

In some solenoid valves, electromagnetic forces act directly on the main valve. Others use small, full solenoid valves, known as manned valves. Piloted valves require much less power, but they are much slower. Such solenoids typically need full power all the time to fully open and hold that position.

The design and purpose of the piloted valve

Gas shut-off pilot valve SCE238A002 (200 bar), Nemen, VIKING, SPOOL, JOUCOMATIC, EVELEN, SMART TORK, consists of two main parts: a throughput device and a direct-acting valve. The pass mechanism converts electrical energy into mechanical energy, which in turn opens or closes the part. A direct acting valve controls the flow of a liquid or gas.

Photo - Solenoid valve

Solenoid valves can use metal seals or rubber seals, and it is also easy to control. The spring is used to keep the valve normally open or closed when not in use.

Pressurized water enters the chamber. The inlet is an elastic membrane, and above it is a spring that pushes it down. The diaphragm has a hole through the center, it allows you to control the amount of water, often a very small part is skipped. This water fills the cavities on the other side of the diaphragm so that the pressure is equal on both sides of the valve.

After the diaphragm is closed by the valve, the bottom outlet pressure decreases and more pressure keeps the valve closed. So the spring has nothing to do with closing or opening the valve.

If current is passed through the diaphragm solenoid, the water in the chamber flows out through the direct passage faster than the chamber is replenished. The incoming pressure raises the diaphragm.

When the solenoid turns off again, the passage is closed by a spring, very little force is needed to push the diaphragm down, the main valve closes again. In practice, there is often no separate spring; The elastomer diaphragm is adapted so that it works like its own source, mostly in a closed form.

Photo - Sirai Solenoid Valves

It can be seen from the explanation that this type of valve depends on the pressure difference between inlet and outlet, since for it to work, the inlet pressure must always be greater than the outlet pressure. If the outlet pressure is, for any reason, higher than the inlet pressure, the valve will open too quickly for this to be prevented by a size difference of no more than half an inch.

To increase pressure, a plastic seal is often used, which is fixed in the area of \u200b\u200bthe inlet.

The connection method for each device is slightly different, so we highly recommend that you read the certificate when buying, check the passport of a specific model. The instructions describe in detail the installation of each individual valve.

Application area

The scope of application directly depends on the material of the valves. The part, the main material of which is brass, is not used in aggressive environments, for example, to control diesel fuel, liquids with an acid base.

Solenoid valves are used to control hydraulic and pneumatic systems, to control cylinders or large industrial valves with large diameters.

Photo - Two-way solenoid valve

Most often, production uses a valve for mechanisms and devices where a limited supply of water, gas, air, etc. is necessary. – washing machine, dishwasher, heating system control. The double-acting pulse valve is used as a device for supplying air and water in dental offices, for watering the earth, feeding various appliances with diesel fuel, controlling the operation of a machine with a mini gas installation, and even for a refrigerator.

Price overview

You can buy a solenoid air, deluge or gas valve with a power of up to 380 volts in Russia, Ukraine, Belarus, at any specialized store. You will find devices of this type: Freon, Honda, SVM, CEME (CEME), SKN for a variety of installations. Each manufacturer offers its own price list, we have collected average prices for valves made in Russia, Italy, Germany and the CIS countries:

All companies provide a guarantee for their products for a year, the sale is carried out in official dealer stores.

When developing my heating system, along with natural circulation, I planned to make myself a forced circulation so that I could attach an automatic regulator to it. After all, what does natural mean: you manually open the necessary tap (or taps), and the heated water itself rises to the batteries, giving off heat there and then descending down to the heater (or to the storage, thermal accumulator). Thus, it is necessary to constantly monitor the temperature in the house in order to turn off the circulation in time, and then, when necessary, reopen it.

Well, it's inconvenient! Did not open on time - it got cold in the house. Did not close - too warm, or even hot. Not only is it uncomfortable, but also overspending when it's hot. And the overspending is not only that the stored heat is unnecessarily spent in the house, but the heat loss of the house also increases, since with an increase in the temperature in the house, the heat loss through the building envelope (walls, ceiling ...) also increases.

So we need automation. There are no difficulties at first glance. The temperature sensor controls, say, a solenoid valve. The temperature in the house dropped - the sensor opened the valve. Increased - the valve closes.

I don't have any problems with the temperature sensor. There is one. But the solenoid valve ... I searched the Internet, joked on the price lists of Internet and non-Internet stores - it's expensive, damn it! And what's the cost of that kind of money? I went to the metal market, talked to people, consulted. To take cheap for 2-3 thousand rubles means to take a one-time. But I don’t have a water supply system, I have heating! If something broke on the water, turned off the water and patched it up, and in winter heating in which case you won’t get any fuss - you need to drain the water, and do it quickly so as not to freeze ... In general, cheap stuff doesn’t suit me, but an expensive valve , for 6-7 thousand rubles ... Yes, and the wife, to put it mildly, persistently objects to such an acquisition.

But I still want automation. In Russia they say: the need for inventions is cunning. And I also decided to dodge and still make automation, but at the same time not upset my beloved and do without an expensive valve. Instead, he put, you will not believe, a check valve. It costs essentially a penny, and at the same time it perfectly performs the functions of an automatic solenoid valve, however, only in tandem with a circulation pump. Have you already guessed what it is? Yes, yes, this is exactly the point: there is a spring in the check valve that presses the rubber gasket to the seat. This spring does not allow the water to move in a straight direction during natural circulation, since the pressure is not so great as to force the elastic from the saddle. But when the pump turned on and started working - everything is fine here, here the pressure increases, the spring is compressed, and water flows freely through the valve and pump.

Hurray, hurrah, and throw caps into the air. But there is one thing that should be taken into account. The strength of this spring was not calculated by engineers for such an application, and even in my heating system. The whole trouble is that the pressure on it during natural circulation directly depends on the height of the water column, that is, on the distance at which the upper point of the uppermost battery is located in relation to this spring. In fairness, it is worth mentioning the dependence on the temperature difference from above and below.

So, in my system, this spring is still a little bit, but skips. That is, there is no complete closure when the pump is turned off. Therefore, I had to simply, without further ado, disassemble the valve and stretch the spring. The video shows this barbaric operation in detail. And only after this "modernization" it was possible to achieve normal operation of automation. That is, I turn on the pump - the water goes, turn it off - the water does not circulate. Now tepericha and caps can be thrown with good reason.

I will answer any questions you may have about the photo. The check valve in series with the top pump is the valve in question. The lower pump is another branch in heating, which is still waiting for its modernization. But the upper pump with a valve, as can be seen in the photo, is shunted with a straight piece of pipe with a tap. What is this for?