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I decided to throw a small article - suddenly someone will come in handy, like me))

I built a small, unpretentious device to maintain a constant water level in the tank. The circuit was taken from the Internet and repeated only with the addition of an elementary parametric voltage stabilizer, since according to the terms of reference, the device must be powered from 24V, and the entire circuit and relay to 12V.

Three-electrode water level sensor.

A diagram of the pump control device is proposed. This scheme is from the set offered by "Master KIT". The pump control device will automate the operation of the suburban pump, with the help of which water enters the shower tank. The principle of operation of the "smart assistant" is as follows, when the water level in the shower tank falls below a certain level L, the pump turns on and starts pumping water into the tank. When the water level reaches the set H level, the device turns off the pump.

This device can be used in the country, in a country house, a cottage. The electrical schematic diagram of the device is shown in the figure.

The circuit is simple and does not need to be configured.

Water has electrical resistance. While there is no water in the tank, transistors T1 and T2 are closed, a high voltage is present on the collector of transistor T1. This high voltage, flowing through the diode D1 to the base of the transistor T3, opens it and the transistor T4, which leads to the switching on of the executive relay, to the power contacts of which the pump is connected. The pump starts pumping water into the container. The LED turns on to indicate that the pump is running. When the water level reaches sensor L, transistor T1 opens, the voltage across its collector drops. However, the pump continues to operate, because voltage is applied to the base of the transistor T3 through the resistor R8 and maintains the TZ-T4 switch in the open state. When the water level reaches the "H" sensor, the transistor T2 opens, and a low level goes to the base of the transistor T3. The TZ-T4 key closes - the relay turns off. Only when the water level drops below the "L" level again, the relay will turn on again. Structurally, the device is made on a printed circuit board made of foil-clad fiberglass with dimensions of 61x41 mm. You can use materials at hand as L and H sensors, such as half-inch copper plumbing nuts firmly attached to insulated wires. Turning on devices. Connect the sensor wires to the board and place them in an experimental container of the same height as the shower tank used at the dacha as follows: "COM" at the bottom (if the container is iron, you can connect this wire to the container body); "L" - at the desired lower water level (pump activation level); "H" - at the level of shutdown of the pump. Connect the device to the power source, observing the polarity. Do not connect mains voltage and pump yet. Turn on the power. The indicator LED should light up and the relay "clicked", connecting the pump. Pour water into a container. When the water level reaches the "H" sensor, the relay should turn off. Empty the container. When the water level drops just below the "L" sensor, the relay should turn on. Now you can finally mount the sensors on a real object and, being careful, connect the 220 V circuit and the pump to the contacts of the circuit.

The advantage of this scheme over simpler ones is the use of relays with only one contact. In almost all similar simpler circuits, 2 groups of contacts are used.

Replacements are possible in the circuit: any bipolar transistors with the specified conductivity. I put B9014 and B9015, but VT5 in the stabilizer - KT805BM in TO-220 with a small radiator. The presence of a radiator is mandatory - the heating is very intense. I also put it on thermal paste. Diodes - any silicon. Capacitors - any with a voltage of at least 16V for C1, C2 and 40V for C3. The bridge (or diodes in the bridge) - for a voltage not lower than the supply voltage and a current of at least 200mA. The current consumption of the circuit when the relay was triggered was 150mA at a supply voltage of 24V. When powered by DC, the bridge can be thrown out. when powered from a 12V (constant) source, you can remove the entire stabilizer circuit.

First version.

I used a combination of DIP and SMD components in the board. The first version of the board, one of the devices is soldered on it. The board of the second is slightly modified: the bridge is removed from the board, the use of a transistor in the stabilizer in the TO-220 package is provided, more SMD elements, increased track width.

The diode bridge is sealed on a separate small board.

To automate many production processes, it is necessary to control the water level in the tank; the measurement is carried out using a special sensor that gives a signal when the process medium reaches a certain level. It is impossible to do without level gauges in everyday life, a vivid example of this is the shut-off valves of the toilet bowl or automatic equipment to turn off the well pump. Let's take a look at the different types of level sensors, their design and how they work. This information will be useful when choosing a device for a specific task or making a sensor with your own hands.

Design and principle of operation

The design of this type of measuring devices is determined by the following parameters:

• By functionality, depending on this device, it is customary to divide into alarms and level gauges. The former track a specific filling point of the tank (minimum or maximum), the latter continuously monitor the level.
• The principle of operation, it can be based on: hydrostatics, electrical conductivity, magnetism, optics, acoustics, etc. Actually, this is the main parameter that determines the scope.
• Measurement method (contact or non-contact).

In addition, design features determine the nature of the process environment. It is one thing to measure the height of drinking water in a tank, and another thing to check the filling of industrial waste water tanks. In the latter case, adequate protection is required.

Types of level sensors

Depending on the principle of operation, signaling devices are usually divided into the following types:

• float type;
• using ultrasonic waves;
• devices with a capacitive level detection principle;
• electrode;
• radar type;
• working on a hydrostatic principle.

Since these types are the most common, let's take a look at each of them separately.

Float

This is the simplest, but, nevertheless, effective and reliable way of measuring liquid in a tank or other container. An example implementation can be found in Figure 2.

Rice. 2. Float switch for pump control

The structure consists of a float with a magnet and two reed switches installed at the control points. Let's briefly describe the principle of operation:

• The tank is emptied to a critical minimum (A in Fig. 2), while the float drops to the level where reed switch 2 is located, it turns on a relay that supplies power to the pump pumping water from the well.
• The water reaches the maximum mark, the float rises to the location of the reed switch 1, it works and the relay turns off, respectively, the pump motor stops working.

It is quite simple to make such a reed switch on your own, and its setting comes down to setting on-off levels.

Note that if you choose the right material for the float, the water level sensor will work even if there is a layer of foam in the tank.

Ultrasonic

This type of meter can be used for both liquid and dry media, while it can have an analog or discrete output. That is, the sensor can limit the filling upon reaching a certain point or track it continuously. The device includes an ultrasonic emitter, a receiver and a signal processing controller. The principle of operation of the signaling device is shown in Figure 3.

Rice. 3. The principle of operation of the ultrasonic level sensor

The system works as follows:

• an ultrasonic pulse is emitted;
• the reflected signal is received;
• the duration of the signal decay is analyzed. If the tank is full, it will be short (A fig. 3), and as it becomes empty it will start to increase (B fig. 3).

The ultrasonic signaling device is non-contact and wireless, so it can be used even in aggressive and explosive environments. After the initial setup, such a sensor does not require any specialized maintenance, and the absence of moving parts significantly extends the service life.

Electrode

Electrode (conductometric) alarms allow you to monitor one or more levels of an electrically conductive medium (that is, they are not suitable for measuring the filling of a tank with distilled water). An example of using the device is shown in Figure 4.

Figure 4. Measurement of liquid level by conductometric sensors

In the given example, a three-level signaling device is used, in which two electrodes control the filling of the container, and the third is an emergency one, to activate the intensive pumping mode.

Capacitive

With the help of these signaling devices, it is possible to determine the maximum filling of the container, moreover, both liquid and bulk solids of mixed composition can act as a technological medium (see Fig. 5).

Rice. 5. Capacitive level sensor

The principle of operation of the signaling device is the same as that of a capacitor: the capacitance is measured between the plates of the sensitive element. When it reaches the threshold, a signal is sent to the controller. In some cases, the "dry contact" version is used, that is, the level gauge works through the tank wall in isolation from the process medium.

These devices can operate over a wide temperature range, they are not affected by electromagnetic fields, and they can be triggered over a long distance. These characteristics significantly expand the scope of application up to severe operating conditions.

Radar

This type of signaling devices can really be called universal, since it can work with any process environment, including aggressive and explosive, and pressure and temperature will not affect the readings. An example of device operation is shown in the figure below.

The device emits radio waves in a narrow range (several gigahertz), the receiver catches the reflected signal and, according to its delay time, determines the capacity of the tank. The measuring sensor is not affected by pressure, temperature, or the nature of the process medium. Dustiness also does not affect the readings, which cannot be said about laser alarms. It is also necessary to note the high accuracy of devices of this type, their error is no more than one millimeter.

Hydrostatic

These alarms can measure both limit and current filling of tanks. Their principle of operation is shown in Figure 7.

Figure 7. Measurement of filling with a gyrostatic sensor

The device is built on the principle of measuring the pressure level produced by a liquid column. Acceptable accuracy and low cost made this type quite popular.

Within the framework of the article, we cannot inspect all types of alarms, for example, rotary-flag ones, to determine granular substances (there is a signal when the fan blade gets stuck in a granular medium, having previously pulled out a pit). It also makes no sense to consider the principle of operation of radioisotope meters, all the more to recommend them for checking the level of drinking water.

How to choose?

The choice of a water level sensor in a tank depends on many factors, the main ones are:

• Liquid composition. Depending on the content of impurities in the water, the density and electrical conductivity of the solution may change, which is likely to affect the readings.
• The volume of the tank and the material from which it is made.
• The functional purpose of the container for the accumulation of liquid.
• The need to control the minimum and maximum level, or monitoring of the current state is required.
• The admissibility of integration into the automated control system.
• Switching capabilities of the device.

This is not a complete list for the selection of measuring instruments of this type. Naturally, for household use, the selection criteria can be significantly reduced by limiting them to the volume of the tank, the type of operation and the control scheme. A significant reduction in requirements makes it possible to independently manufacture such a device.

We make a water level sensor in the tank with our own hands

Let's say there is a task to automate the operation of a submersible pump for water supply to a summer cottage. As a rule, water enters the storage tank, therefore, we need to make sure that the pump automatically turns off when it is full. It is not at all necessary for this purpose to buy a laser or radar level signaling device, in fact, you do not need to purchase any. A simple task requires a simple solution, it is shown in Figure 8.

To solve the problem, you will need a magnetic starter with a 220 volt coil and two reed switches: a minimum level for closing, a maximum for opening. The pump connection diagram is simple and, importantly, safe. The principle of operation was described above, but let's repeat it:

• As the water rises, the float with the magnet gradually rises until it reaches the maximum reed switch level.
• The magnetic field opens the reed switch, disconnecting the starter coil, which leads to a de-energization of the motor.
• As the water flows, the float descends until it reaches the minimum mark opposite the lower reed switch, its contacts close, and voltage is supplied to the starter coil, which supplies voltage to the pump. Such a water level sensor in a tank can work for decades, unlike an electronic control system.

To regulate and control the level of liquid or solid matter (sand or gravel) in production, in everyday life, a special device is used. It is called the water level sensor (or other interesting substance). There are several varieties of such devices, which differ significantly from each other in their principle of operation. How the sensor works, the advantages, disadvantages of its varieties, what subtleties when choosing a device should be paid attention to and how to make a simplified model with a relay with your own hands, read in this article.

The water level sensor is used for the following purposes:

Possible methods for determining the tank load

There are several methods for measuring liquid level:

1. Contactless- often devices of this type are used to control the level of viscous, toxic, liquid or solid, free-flowing substances. These are capacitive (discrete) devices, ultrasonic models;
2. Contact- the device is located directly in the tank, on its wall, at a certain level. When the water reaches this indicator, the sensor is triggered. These are float, hydrostatic models.

According to the principle of operation, the following types of sensors are distinguished:

• Float type;
• Hydrostatic;
• Capacitive;
• Radar;
• Ultrasonic.

Briefly about each type of device

Float models are discrete and magnetostrictive. The first option is cheap, reliable, and the second is expensive, complex design, but guarantees an accurate level reading. However, a common disadvantage of float devices is the need for immersion in liquid.

Float sensor for determining the level of liquid in the tank

1. Hydrostatic devices - in them all attention is paid to the hydrostatic pressure of the liquid column in the tank. The sensitive element of the device senses pressure above itself, displays it according to the scheme to determine the height of the water column.

The main advantages of such units are compactness, continuity of operation and affordability in the price category. But they cannot be used in aggressive conditions, because one cannot do without contact with liquid.

Hydrostatic liquid level sensor

1. Capacitive devices - plates are provided to control the water level in the tank. By changing the capacity indicators, one can judge the amount of liquid. The absence of movable structures and elements, a simple scheme of the device guarantee the durability and reliability of the device. But one cannot fail to note the disadvantages - this is the obligatory immersion in liquid, exactingness to the temperature regime.
2. Radar devices - Determine the degree of water rise by comparing the frequency shift, the delay between emission and arrival of the reflected signal. Thus, the sensor acts as an emitter and a reflector catcher.

Such models are considered the best, accurate, reliable devices. They have a number of advantages:

The disadvantages of the model include only their high cost.

Tank liquid level radar sensor

1. Ultrasonic sensors - the principle of operation, the circuit of the device is similar to radar devices, only ultrasound is used. The generator creates ultrasonic radiation, which, upon reaching the surface of the liquid, is reflected and after a while falls on the receiver of the sensor. After a little mathematical calculations, knowing the time delay and speed of ultrasound movement, determine the distance to the water surface.

The advantages of the radar sensor are also inherent in the ultrasonic version. The only less accurate indicators, a simpler scheme of work.

The subtleties of choosing such devices

When buying a unit, pay attention to the functionality of the device, some of its indicators. The extremely important questions when buying a device are:

Options for sensors for determining the level of water or solids

DIY liquid level sensor

You can make an elementary sensor to determine and control the water level in a well or tank with your own hands. To perform a simplified version, you must:

A DIY device can be used to regulate water in a tank, well, or pump.

The application of water level sensors, in fact, is much wider than it seems at first glance. They are used to measure the water level in containers of various types and purposes. Distinguish:

Water is used everywhere, both at home and at work. And everywhere there is a need to control its level, since the overflow or emptying of the container can lead to serious negative consequences.

The level can be measured either continuously using level gauges and level indicators, or pointwise using level limit switches.

How to choose a device for measuring the water level?

Water level sensors are used to measure its amount in a conventional tank. In our catalog there are more than 30 types of water level control sensors. We are ready to advise, as it is important not to make the wrong choice.

The main selection criterion is the operating conditions. You should also take into account what kind of data needs to be monitored (water reaching a specific point, continuous level measurement, etc.), the size and purpose of the tank, the possibility of mounting the sensor, etc.

Water level alarms

When contact with the medium arises or disappears, these devices signal that the limit level has been reached. The alarms are used to prevent overflow of the tank / dry running of the pump, to maintain the set water level within the set limits, and also as a warning signal.

Level gauges for continuous measurement of water level

These gauges continuously indicate the degree of filling of the container. Level gauges can be used for:

• monitoring the amount of water in various tanks,
• dosing,
• process control.

Most level gauges (with the exception of microwave, acoustic and radar) use a probe immersed in a liquid for measurement. This is where differences in operating principles begin. Our catalog contains level gauges for various purposes. The choice of the right one depends on many factors, such as: type of container, conditions and place of operation, etc.

Water level indicators

Water level indicators are used exclusively for monitoring the level of the water column. There are no elements in them that convert mechanical action (increase / decrease in the water level) into an electrical impulse. Therefore, you can control the level change using the indicators only by observing the scale on them.

Water is essential in almost any technological process. In any industry, it is used for different purposes, be it:

• hardening,
• turning and milling (here water is used as part of the coolant),
• at nuclear power plants (as a working fluid),
• for food production,
• irrigation of fields, etc.

The list of applications is endless. And where the use of water is necessary, its storage is also required. Accordingly, you need to know its amount, which is currently prepared for use. In many technological processes, constant level control is indispensable. Level switches, level gauges and indicators can help in solving such problems.

There are a large number of types of tanks that differ in the field of application, and at the same time are suitable for storing water.

• In private homes, they are used to store drinking water and water for general needs;
• In areas with vegetable gardens, orchards, as well as in the agricultural industry, they are installed for water supply to irrigation systems;
• In industry, tanks are used for:
  • heating systems (boilers),
  • transportation of water (tank trucks),
  • storage,
  • filtration,
  • water treatment,
  • water supply of various technological processes.

It is very important that these containers are not empty or overflowing. In order to prevent such moments that can lead to emergency situations, level limit switches are installed in the tanks.

In the pool, a water level sensor, installed to constantly monitor the amount of water, controls the pumps via a frequency converter to keep the level within the set limits.

For this, a system of "communicating vessels" is installed, where the pool is the main one, and the container is representative, connected to it by pipes. Only a certain type of water level sensor can be installed in this container.

In this case, level gauges that measure the water level using a probe (potentiometric, capacitive, magnetostrictive, etc.) are suitable.

For owners of private houses and summer cottages, it is very important to know the amount of remaining water in wells, wells, boilers of the heating system. This is necessary so as not to be left without water at the most inopportune moment. To do this, we propose to install sensors in these tanks for measuring the maximum water level, which notify about filling or emptying.


Well water level control

It is very important to monitor and control the water level in the well in order to prolong the life of the submersible pump. In order to know the moments of filling and emptying the well and to prevent dry running of the pump, you can buy water level sensors.


Well water level control

Using a well as a source of water supply also requires the delivery of water to the house or to an intermediate tank for its further storage, which requires the installation of a submersible pump. And, accordingly, the same problems arise as in the well (dry running of the pump and overflow).

There are many solutions where water level sensors control pumps in a well. You can familiarize yourself with one of the cheapest methods in the article: "The use of water level sensors in wells."


Wastewater level control

It is very important for owners of private houses to know when the cesspool will fill up in order to order the appropriate services for its emptying. Since in solving this problem we do not need to know the exact amount of wastewater, we can install one cable float switch for filling. In order to obtain correct data on the level of wastewater in the well, the alarm device must be selected from a material that does not adhere to sticking.


Monitoring the water level in the heating boiler

If you are using an internal heating system, it is very important not to run out of hot water. Setting the water level indicator will be more than sufficient. An important point to pay attention to will be the technical characteristics of the temperature sensor.

Thus, after installing a water level control system, you will not be left without heat and water supply at the most inopportune moment.

To summarize: if high accuracy is not important to you when measuring the amount of water, then level switches can solve most of the tasks.

Now let's look at the use of water level sensors in industrial tanks. Let's do this using the example of a water treatment plant.

To monitor and control the amount of water at treatment plants, special monitoring and alarm systems are installed, consisting of: water level sensors in tanks, flow meters, level switches, controllers, frequency converters and, finally, pumps. All these systems allow preventing accidents in the production of filtered water, as well as managing systems for bottling and transferring water to the consumer.

Before you buy water level sensors in a tank, you need to decide on the purposes of its application. The choice of water level sensors in the tank is determined based on the production need and the parameters of technological processes.

For the correct choice of a level sensor, it is necessary to know the technological parameters: the conductivity of the medium, the depth / size of the container, its location, etc. For different purposes, the same level gauges, indicators and level switches can be used, and for some, only special sensors. For advice on choosing the sensors you need, please contact our support service.

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Hello everyone. Today we will talk about a very simple set for self-assembly of the device to control the water level. This set can be successfully soldered by a 5-7 grade schoolchild in one evening. You can, of course, do it completely yourself, including the fee, but I decided to save time, so a set was ordered.

The set was purchased in order to at least somehow automate the collection of water in a barrel in the country. Moreover, this is not really a barrel, but rather a pipe going down 2.5-3 meters, so the water reserves there are decent (for simplicity, let it be a barrel). The idea was simple, as long as there is no regular water supply, the solenoid valve opens and draws water into the barrel at a given level. Water consumption in buckets as needed and automatic topping up into the barrel. In order to prevent the valve from often triggering from water fluctuations, several levels are conceived. The lower one at which the valve turns on and the upper one at which it turns off. Those. there is a certain dead zone at which there is water flow, but there is no water supply to the barrel yet. By the way, this dead zone is actually such a thing as hysteresis.
Last year, this function was performed by such a device as a float mechanism from a toilet cistern. It worked properly, occasionally it got clogged, since water flows through pipes straight from the river. But in the end, the winter did not survive, because it was made of plastic and fell apart from the frost.
This set was intended to replace the failed mechanism.

As we kept the collected board and waited for the summer cottage, an attempt was made to apply the collected board in production, on such an installation.


It is just a large saucepan with a 27 kW heating element type heater. The products are taken out of the refrigerator in whole pallets and placed in a pan. It is necessary to heat all this up to 90 C. Can you imagine how much electricity is spent on a daily basis ?!

To estimate the volumes, I will attach a couple of photos:

The products, among other things, are pork stomachs and curls (part of the intestines).
As far as I know, stomachs are stuffed with something and eaten, with intestines it is about the same - including sausages with sausages.

This case is boiled and re-frozen. Then it goes to China. So, the cycle of goods in nature. We give them natural offal, and in return, electronics ...

The question is ripe to transfer the heating of the pan to steam. So more economical and higher power. Performance increases significantly. This is where a level sensor was required so that no one would scald with steam and steam was supplied only when there was at least a minimum amount of water in the tank.

However, I caught myself in time and abandoned the final installation, although tests showed that the board worked. It is contraindicated to use homemade products in the production. Therefore, we found a less operatively needed device that performs the same functions, but also has a certificate. The principle of operation of a factory device practically corresponds to a set from an online store and in a particular case performs the same functions.
This device is of domestic production Aries SAU-M7.

Delivery and packaging:

Bangud is very stable, small bag and several layers of polyethylene foam.

In a small bag there is a "bunch" of parts, a board and wires.


I did not sort by denominations, I just spread them out for clarity.


The scheme is not simple, but very simple. 4 elements of 2AND NOT are used, with two of them performing the function of a trigger. It is needed to form a hysteresis loop.
Pins 1 and 2 of J3 give a low signal and turn on the relay. Contacts J4 1 and 2 - upper level and emergency, when any of them is triggered, the relay turns off. Relay operation is duplicated by LED lighting. The scheme reliably works on tap water and just as confidently on water after water treatment, in which there are fewer salts.
I assembled the board practically without looking at the circuit, except that I looked at the value of the resistors.
It is unlikely to mix up the leads, and even the installation of parts such as connectors or transistors will be incorrectly interfered with by the applied silkscreen.
The only drawback during installation is that I mixed up the LEDs. But this is so, little things, they do not affect performance.


Self-made conductometric level sensors were used as sensors. This is how they look when assembled:

On the board from the side of the installation of parts, silk-screen printing is applied, quite high quality.


You will not be interested in the process of desoldering parts, since I am not an assembler and do not know the features of those process for assembling boards. What I got into my hand from the edge, I sealed it.
The printed circuit board is covered with a protective mask on the soldering side. There is no metallization. The board is one-sided.

I used POS 61 type solder with rosin. I swore a little.


The power wires were fixed with a sealant so that they would not break off at the exit from the holes. The wires that came with the kit seemed to me too short.


I washed the board with a solvent and alcohol and covered it with a layer of Plastik 70. Immediately noticed the difference between my previous boards and this one. The surface is shiny and the contacts are covered with a layer of film.
Some inconvenience came to light, which is actually a plus. I wanted to shoot a video about the operation of the board using a multimeter, but I got a problem in the form of the fact that the circuitry does not corny pushing through the protective coating. Therefore, there is no multimeter in the video.

Video demonstration of the board:

Upd: while writing the review, I did not even pay attention to the product page, as usual. And only after writing the review did I pay attention to the product. The board does not match the one that was sent to me and, judging by the comments, many are sent two different board options. This does not affect the functionality. Both boards are functional.

Outcomes: The simplest set, available for schoolchildren, also has practical application. I recommend it for purchase. The sediment remained small due to the fact that the board did not come from the one in the description.

In my case, the wires turned out to be superfluous. They were probably planned for outputting LEDs from the board to the front panel and connecting a power supply.

I plan to buy +52 Add to favourites I liked the review +25 +47