check valve design:

check valve- type designed to prevent the formation of backflow. Check valves allow flow working environment in one direction and prevent its movement in the opposite direction, while acting automatically and being a direct acting armature.

With the help of non-return valves, various equipment, pipelines, pumps and pressure vessels are protected, and it is also possible to significantly limit the flow of the working medium from the system when its section is destroyed.

Depending on the design and principle of operation locking organ, check valves can be divided into: lift, ball, flap and axial, as well as rotary check valves.

The simplest in design and manufacturing technology - lift valves. The locking body in them is a spool, which moves back and forth in the direction of the flow of the working medium. In the absence of medium flow through the armature, the spool in the check valve is in the “closed” position under the action of its own weight or spring, that is, the shut-off element is in the body seat. When a flow occurs, the spool, under the influence of its energy, opens a passage through the saddle. If the flow changes its direction, the spool returns to the closed position and is additionally pressed by the pressure of the medium itself.

Lift valves are installed only on horizontal sections pipelines. Required condition– vertical arrangement of the valve axis. The main advantage of a check lift valve is that it can be repaired without dismantling the entire valve. The disadvantage is high sensitivity to environmental pollution.

IN ball check valves the locking element is a spherical element, and the clamping element is a spring. Ball check valves are usually used on small diameter pipelines, mainly in plumbing.

The most compact design among check valves axial and double-leaf flap valves. In a spring disc valve, the shutter is a disc with a clamping element - a spring. In working condition, the disc is squeezed out under water pressure, providing a free flow. When the pressure drops, the spring presses the disc against the seat, blocking the flow hole. In complex hydraulic systems, double-leaf valves are used. In them, the locking disc is folded in half under the action of the flow of water. The reverse flow returns the disc to its original state, pressing it to the seat. Size range 50mm - 700mm, even larger than spring loaded disc valves.

The main advantages of wafer type check valves are their smaller size and lighter weight. In their design there are no flanges for fastening to the pipeline. Due to this, the weight is reduced by 5 times, and total length 6-8 times compared to standard check valves given bore diameter. Advantages: ease of installation, operation, the ability to install, in addition to horizontal sections of the pipeline, also on inclined and vertical ones. The disadvantage is that complete dismantling is required when repairing the valve.

Swing check valves, or check valves are used for highly large diameters pipelines. In this design, the locking element is a spool - "slam". The axis of rotation of the "flap" is above the through hole. Under the action of pressure, the "clap" leans back and does not prevent the passage of water. When the pressure drops below the permissible value, the spool falls and slams the through passage. With a pipeline diameter of more than 400 mm, rotary check valves are equipped with special devices that make the landing of the flap on the seat smoother and softer. As such devices, hydraulic dampers and weights are used, which are installed directly on the flap or using a lever. A significant disadvantage of unstressed structures is the impossibility of their installation on any sections of the pipeline, except for horizontal ones. In general, check valves have a number of advantages over check valves, including less sensitivity to contaminated media.

S. Deineko

For systems of centralized hot water supply around the world, the issue of protection against legionella is relevant. This is especially true for branched DHW systems in apartment buildings. The use of special balancing valves helps not only to reduce the risk of bacterial growth, but also to a large extent save water.

With the formation of stagnant zones in DHW systems, at a certain temperature, dangerous for human body bacteria - legionella (Legionella pneumophila). They are the causative agents of legionellosis, a disease similar in symptoms to pneumonia, which makes it difficult to make an accurate diagnosis.

The disease was first diagnosed in the United States after an incident that occurred in 1976 during the convention of the American Legion, an organization that unites veterans of various military conflicts (hence the name of the disease - "legionellosis"). Among the delegates living in a hotel in Philadelphia, there was an outbreak of a previously unknown disease that claimed the lives of 34 out of 220 sick people within a month.

Since then, in many civilized countries of the world, hundreds of cases of the disease are recorded annually, including fatal ones. The sources of reproduction of bacteria are determined by the optimal temperature for their vital activity - 20-50 °C (Fig. 1). These are air conditioning and ventilation systems, hot water supply, low-temperature heating.

Rice. 1. Influence temperature regime on the vital activity of legionella

Legionella enters the internal network engineering from natural sources- fresh water and soil. The most suitable environment for the reproduction of pathogenic bacteria is biocolonies that form on the walls of pipelines (therefore, they are less prone to this plastic pipes with a smooth inner surface) and other elements of systems. The risk of formation of such substances is especially high in water supply networks with long and branched pipelines, where, due to imbalance during the absence of water analysis, water stagnation is observed.

To combat legionella, methods such as disinfecting water with chlorine or ozone are used. However, in the case of hot water, the most acceptable and effective is the thermal effect. It consists in maintaining a high temperature of water in the pipelines of the system with the prevention of stagnation, as well as short-term heating of water to values ​​\u200b\u200bcritical for the survival of bacteria.

Balancing

For DHW systems in apartment buildings, the following situation is typical - when disassembling water, hot water goes through the water-folding unit closest to the heat source. At the same time, less heated water, which has cooled down during the period of no water analysis (for example, at night), is supplied to the connection points located on the floors above. Thus, the consumer is forced to drain this water until it reaches the flow with the required temperature. And the longer the pipelines, the more water is drained into the sewer. As a result - large losses in the water supply system. In addition, the last consumer on the line may not wait hot water with standard settings.

This is especially true for buildings commissioned in the 70-80s of the last century, in the DHW systems of which there is no circulation line or the circulation system does not function due to physical wear and tear.

However, even in houses with an operating circulation line, the required water temperature is not always reached immediately after the opening of the water assembly. Indeed, until recently, circulation lines (T4 in Fig. 2) were equipped only according to the principle of changing hydraulic resistance different diameters pipelines, that is, the diameter of the circulation pipe varied, depending on the distance from the source of water heating, and was less than the diameter of the supply pipeline of the DHW system (T3). At the same time, the temperature in the circulation line was not controlled and was not taken into account, which also led to excessive consumption of electricity for the operation of the circulation pumps.

In order to avoid such situations in new buildings, special balancing valves have been installed on the circulation lines for several years. They can also be used in the reconstruction of existing hot water systems.

These valves differ in that, in addition to a given flow rate through the circulation line, using the so-called thermal actuator, it is possible to set the required water temperature in the circulation line, for example, in the range from 40 to 65 °C. If the temperature drops, the valve opens and lets water through for heating. At the same time, there is no constant need for hot water circulation. It appears only when there is no water analysis in the system. Estimated value The temperature of the water in the circulation line is, as a rule, no more than 5-10 ° C from the temperature of the water in the DHW system. This indicator is affected by:

• diameters and length of pipelines;
• air temperature in places where pipelines are located;
• efficiency and condition of thermal insulation.

The balancing valve allows you to adjust the flow of water through the circulation line. The use of a thermal drive with it makes it possible to control the water temperature: when it decreases in the circulation line, the valve will be open until the temperature reaches the set value. After that, the thermal actuator blocks the flow and turns off the circulation pump.

Thus, due to the use of balancing valves with thermal actuators, a constant temperature is maintained in the DHW system. This reduces waste of water and also reduces the risk of bacterial growth.

On fig. 2 shows the places for achieving the greatest efficiency of the balancing valves in the DHW system, i.e. they should be located after the last draw-off point. There are modifications of balancing valves with thermal actuators for systems in which thermal disinfection of water is provided.

Rice. 2. Scheme of the DHW circulation system with balancing valves

Thermal disinfection

For the complete destruction of legionella in hot water systems, a short-term heating of the water in the system by a boiler is used to temperatures that are critical for the life of bacteria - for example, above 60 ° C for half an hour. As a rule, this is done at night in the absence of water analysis.

The thermal actuator (Fig. 3) of balancing valves designed for systems with thermal disinfection operates according to the following principle. When the temperature rises above 62 ° C, the drive does not close, but, having reached the limit, on the contrary, it opens.

Rice. 3. Thermal drive

Structurally and technically, it works quite original. An insert from a stem with a certain set of washers at a large increase in temperature falls beyond the limit of shutting off the flow. The process occurs due to mechanical expansion. But if the temperature rises above 72 °C, the valve will close again (Fig. 4) in order to avoid thermal burns of consumers.

Rice. 4. Regulating characteristics of the balancing valve with thermal disinfection function

The thermal disinfection function is supported by many modern controllers, such as the Smile type (Honeywell). In carrying out this process, it is important that the required high temperature is reached at all points in the system. Therefore, the pump must be switched on in the mode of increased circulation, and automatic balancing valves provide the desired hydraulic balance.

In private construction and in apartments with electric boiler can be disinfected manually. Periodically (once a month) heat up the boiler to the limit and drive water through the system. This is especially recommended before seasonal use of the boiler (during summer shutdowns of centralized hot water supply).

Device examples

The installation of balancing valves on the recirculation lines of hot water systems has been practiced in Ukraine relatively recently - about 3-4 years. Now in new buildings with an extensive DHW system, their installation is necessarily provided. After all, without hydraulic balancing, for example, for high-rise building with 6-10 entrances and with several risers in each, it is practically impossible to hydraulically “link” the circulation lines of the first and last entrances.

It is important to know that in DHW systems it is unacceptable to use balancing valves designed only for heating systems. After all, despite the similarity of the tasks being solved, there are a number of features. For example, valves for DHW circulation systems are made of materials that are resistant to corrosion and meet the relevant hygiene requirements.

Balancing valves for DHW systems manufactured by Danfoss (Denmark), Honeywell (Germany), Oventrop (Germany) and others are presented on the Ukrainian market.

For example, balancing valves for hot water supply Alwa-Kombi-4 (Honeywell) (Fig. 5) are made of corrosion-resistant red bronze grade Rg5. Hydraulic balancing is carried out by manual installation water flow through the valve, according to the calculations for the required pressure drop for each circuit. To automatically control the water temperature, the valve is equipped with a thermal actuator. In the standard version, it maintains the required water temperature in the range of 40-65 °C (insert with a black cap), in a special version, a thermal drive is provided with the function of supporting thermal disinfection (supplied with an orange cap). The Alwa-Kombi-4 can be retrofitted with a thermal actuator at any time, even after installation on the system. The valves are resistant to high temperatures(up to 130 °С) and pressure (up to 16 bar). Diameters - from 15 to 40 mm.

Rice. 5. Balancing valve for DHW system (Alwa-Kombi-4)

There are also automatic mixing valves that keep the water at a constant temperature after mixing. They are installed both at individual points of water intake (washbasin, shower, etc.), and at their small groups, for example, in preschool institutions or schools.

Backflow protection

To protect water supply systems from the ingress of contaminants and pathogenic bacteria during gusts or penetration by counterflow, special shut-off devices (Backflow Preventer, English - "backflow prevention device") are used in the EU countries.

According to European standards EN 1717, they must be installed at every water supply installation - at the entrance to buildings, as well as on distribution lines - up to the apartment. The purpose of their application is to prevent the ingress of polluted water into the centralized water supply system.

The devices have three chambers (Fig. 6), which overlap in the event of a sharp decrease in inlet pressure or an increase in the back pressure of water from the consumer. At the same time, contaminated water is cut off and drained into the sewer. Thus, unwanted impurities do not enter the internal and external networks of the water supply system.

Rice. 6. Backflow preventer (BA-295, Honeywell)

There are various modifications of shut-off valves, depending on the category of buildings. However, they have not yet received mass distribution in Ukraine due to the lack of domestic standards for their mandatory application.

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For many novice plumbers, it holds many mysteries and mysteries. In this article I will try to explain how it will work with a servo of three different models. We will consider the logic of operation and the electrical wiring diagram.

Option 1: The price is from 6300 to 9200 rubles. Item options may be available.

Option 2: The price is about 2500-5000 rubles, if you try to find it on a Chinese website and order from China.

Option 3. An expensive option, but there are a lot of options. The price can be about 15-20 thousand rubles.

Wiring diagram for a three-way valve with a servomotor for domestic hot water

The valve can be installed both on the supply line (supply) and on the return line of the pipeline (return).

Many will ask the question:- Where is it better? For delivery or return?

In terms of the functionality of the DHW, this is not important. But there are some nuances why it is necessary to put on the supply or on the return line.

Nuances between supply and return:

anyone Do any of you know why it is necessary to put a hydraulic accumulator on the return line of the pump? Or believes that it can be placed anywhere? Do you know why the pump is put on supply or return? Answer: This is because from where these elements are located, the pressure distribution at different points of the pipeline changes. And in some cases, again, the reason is the convenience of filling and draining the coolant in the heating system. It also helps to avoid airing and much more.

And why in the instructions for boiler equipment, it is recommended to keep the pressure at least 1.5 bar? Because the pressure in the boiler heat exchanger must not be reduced! The decrease in pressure leads to cavitation of the coolant in the heat exchanger. It also leads to early boiling of the coolant. And all this leads not only to a decrease in the power of the boiler, but also to the deposition of scale in the heat exchangers, which leads to the deposition of scale and overgrowth of the heat exchangers. Which in turn will lead to a short service life of the boiler equipment.

Do you think, if the pressure gauge shows 1.5 Bar, does this mean that pressure less than 1.5 Bar cannot be present in the system at the same height as the pressure gauge? Answer: This may be more often the case with the owners, who independently figure out where the pump and accumulator will stand. And they don’t understand how the pressure will be distributed after that.

Also how does the accumulator affect the pressure distribution: http://santeh-baza.ru/viewtopic.php?f=2&t=93

Why do you need a three-way valve for domestic hot water?

The main task of the three-way valve for hot water supply is to redirect the movement of the coolant from the heating system towards the indirect heating boiler (another heat exchanger) and back in automatic mode.

As soon as the command came to heat the indirect heating boiler, the coolant must be redirected towards the BKN coil. The heating signal is generated by a special relay, which is located at the BKN (Indirect Heating Boiler). That is, BKN has a built-in electrical thermal relay, which provides a switching contact.

What does a three-way valve for domestic hot water look like?

The electrical diagram of the valve for the domestic hot water supply of the Thermona boiler?

Wiring diagram with boiler and boiler

The servo has three pins, one common. If you give a voltage of 220 Volts to two contacts (direction 1 + common), there will be one position. To another position, you need to give a voltage of 220 Volts to the other contact (Direction 2 + common). The phase and zero of the 220 Volt network is not important.

Option 3. The most difficult option, which requires more detailed study. It has a variety of functionalities.

If you have a more efficient heating system + hot water with high costs. Then it is not possible to use valves of option 1 and 2, since they have a low throughput!

This device consists of two parts:

1. Rotary mixing valve (diameter optional)

Servo drive ESBE

Servo Model: ESBE ARA641 220 Volt. 30 seconds. Article number 12101100

Drive characteristics:

1. Rotate 90 degrees. There is a degree adjustment setting. You can do a little more or move a little to the side.

2. 3x point control. That is, 3 contacts 220 Volts for control: Terminal 1, terminal 2 and common terminal.

3. The time it takes for the actuator to turn 90 degrees depends on the model. Model ARA641 30 sec.

4. Wire cable 1.5 meters.

5. Torque force: 6 Nm.

Servo drive wiring diagram: ESBE ARA641

This device has three conductors: Blue, brown and black.

Blue- a common conductor, usually Zero is closed to it

Brown and black These are position 1 and 2 conductors.

When there is a voltage of 220 volts, the blue and black drives turn in one direction by 90 degrees.

When there is a voltage of 220 volts on the blue and brown drive turns in the other direction by 90 degrees.

These servos have a button to turn off the direction of movement. That is, you can force the valve to the desired position during the repair or test.

Note that the more threads, the more torque may be required.

In the ESBE catalog You can pick up other valves and servos!

For example,

1. Select not three-point (three-contact) control, but two-point control. That is, a constant voltage goes to one contact, and you simply give or take voltage to the second contact.

2. The rotation angle can be more than 90 degrees. For example, 180 degrees.

3. Closing time is not 30 seconds, but much longer. For example, you may need a smooth transition up to 1200 seconds.

4. Take a drive with a different torque force.

5. Drive for 24 or 220 volts.

6. You can choose not only for switching, but also for obtaining the desired temperature by mixing.

Download ESBE catalog for valve and actuator selection: esbekatal.pdf

If one has a two-point signal from an indirect heating boiler or from some thermostat that only has a two-point contact, then an electromagnetic switching relay can be used.

This model should be looked for in specialized stores of electricians and electronics.

Model: ABB CR-P230AC2. Pins 1 and 2 are supplied with 220 volts. Do not exceed 8 amps for changeover contacts. 8 A x 220 Volts = 1700 W. Withstand equipment up to 1700 watts. It does not apply to pumps and incandescent lamps, since the first start-up requires high currents.

In order to connect it to the wires, a special connector is used:

Base ABB CR-PLSx (logical) for relay CR-P

You should get the following:

That's actually all. Ask questions! Have you understood everything? Maybe something is missing?

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A series of video tutorials on a private house
Part 1. Where to drill a well?
Part 2. Arrangement of a well for water
Part 3. Laying a pipeline from a well to a house
Part 4. Automatic water supply
Water supply
Water supply of a private house. Principle of operation. Wiring diagram
Self-priming surface pumps. Principle of operation. Wiring diagram
Calculation of a self-priming pump
Calculation of diameters from the central water supply
Water supply pumping station
How to choose a well pump?
Setting the pressure switch
Pressure switch wiring diagram
The principle of operation of the accumulator
Sewerage slope per 1 meter SNIP
Heating schemes
Hydraulic calculation of a two-pipe heating system
Hydraulic calculation of a two-pipe associated heating system Tichelman's loop
Hydraulic calculation of a single-pipe heating system
Hydraulic calculation of the beam distribution of the heating system
Scheme with a heat pump and a solid fuel boiler - the logic of work
Three-way valve from valtec + thermal head with remote sensor
Why the heating radiator in an apartment building does not heat well
How to connect the boiler to the boiler? Options and connection diagrams
DHW recycling. Principle of operation and calculation
You are not doing the calculation of the hydraulic arrow and collectors correctly
Manual hydraulic heating calculation
Calculation of a warm water floor and mixing units

The three-way mixing valve is designed to mix two incoming streams (cold and hot) into one outgoing one with a given temperature. These valves are particularly in demand in domestic hot water systems to protect consumers from scalding. They can also supply hot water directly from instantaneous or accumulative type or used in the preliminary mixing step. No less often used to maintain a stable supply temperature in underfloor heating systems.

Principle of operation.

The internal regulation of the valves is carried out automatically due to the presence of a temperature sensing element that contacts the mixed flow and contracts or expands depending on the deviation of the mixture temperature from the set outlet value, thereby increasing or decreasing the hot or cold water.

How does burn protection work?

Most thermostatic valves on the market today have a temperature protection device - "scalding protection". In the event of an unexpected interruption in the supply of cold water to the valve, the supply of hot water is automatically shut off, thereby eliminating the possibility of supplying hot water without prior mixing to the consumer.

Flow direction.

There are two flow patterns in a thermostatic valve - symmetrical and asymmetric. Choice certain scheme depends on the type of installation and ease of installation in a particular heating or hot water system. Let's take a closer look at each of them.

GV- hot water;

XV- cold water;

SW- mixed water.

symmetrical T-shaped scheme of flow direction

Cold and hot water is supplied from opposite sides, mixing occurs in the middle. This scheme is very common in Europe, due to the compactness of the valves.

Asymmetrical L - figurative scheme of flow direction

Hot water is supplied from the side, cold - from below. It gained its distribution due to the versatility and simplicity of the resulting mixing unit.

Examples appearance thermostatic valves with symmetrical and asymmetric flow direction:

	Watts AquaMix (Germany)	Danfoss TVM-H (Denmark)

It is about thermostatic valves with an asymmetric flow pattern that will be discussed further.

Areas of application for thermostatic mixing three-way valves.