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Hydro heating. What is a hydraulic arrow? Purpose and principle of operation. Additional features and myths

Classic way Connecting the boiler to the heating system has a number of serious disadvantages. For example, it may not produce the rated power and, if adjustment is necessary, loses balance. There are significant temperature fluctuations inside the boiler, and choosing pumps for such a model is a real problem. Currently, these shortcomings are corrected using a hydraulic arrow for the heating system.

What is a hydraulic arrow in a heating system

Hydroarrow(hydraulic separator, hydraulic arrow) – part heating system, with the help of which the heating circuits are joined. It provides the smallest pressure difference between them, which makes it possible to turn off one without losing pressure in the others. In other words, the hydraulic arrow for the heating system removes the influence of the heat consumer pumps on the circulation pumps of the heat source and in the reverse order.

In addition, the hydraulic arrow is used for hydrodynamic balancing of heat supply. This simple device plays important role throughout the heating system of the home. The hydraulic separator prevents the formation of thermal shock in cast iron heat exchangers and boilers.

Some boiler manufacturers include in the document about maintenance clause on the installation of a hydraulic arrow for heating. Without its use, the buyer loses the warranty on the device (for example, on a floor-standing gas boiler).

The hydraulic arrow for heating systems is balanced by the hydrodynamic parameters of the system. Thus, the mutual influence of various thermal circuits on each other is completely eliminated, which leads them to operate without failures and maintain the specified parameters and modes.

In addition to the above-described capabilities, a hydraulic gun for heating systems can also clean the coolant from impurities, for example, sand or rust (for this it is necessary to correctly calculate the parameters). In addition, the hydraulic separator also removes air from it, and this, in turn, extends its service life. metal parts, since their oxidation slows down. Increased service life shut-off valves, pumps, sensors, radiators and heat exchanger directly affects the reliability and durability of the entire heating system.

The hydraulic boom performs the following functions:

Function for maintaining hydrobalance in the heating system. Elimination of the influence of one circuit on the hydraulic characteristics of the others when turned on and off.

Preservation function for cast iron boiler heat exchangers. The operation of a hydraulic arrow for heating systems protects heat exchangers from sudden temperature changes that may occur when the boiler is first started or when repair work oh, when the circulation pump is turned off. It is well known that such differences have a negative impact on cast iron devices.

Air vent function. The hydraulic arrow is also needed to remove air from the heating system. For these purposes, a pipe is mounted on it in its upper part, intended for mounting an automatic air vent.

Coolant filling and draining function. The vast majority of hydraulic arrows, both industrial and self-made, are equipped with drain valves, with the help of which the coolant is filled or drained from the heating system.

Heating system cleaning function. In the hydraulic arrow, the coolant moves at a reduced speed. So this setup collects various kinds dirt: scale, rust, sand, scale, and so on. These solid fractions accumulate in the lower part, which allows their removal through the drain valve. There are models of hydraulic arrows that are equipped with magnetic catchers for collecting metal debris.

Why is a hydraulic arrow needed in the heating system of a private house?

To the question: “Why do you need a hydraulic arrow in a heating system?” You can answer the following. The main goal installation of this device in a heating system is to separate the fluid flows inside it, as well as to protect boilers and associated equipment. Below are the main situations in which it may be necessary to install a hydraulic arrow in the heating system:

Typically, a hydraulic arrow is installed in rooms with an area of ​​more than 200 m2.

If it is necessary to create more than two circuits in a heating system with different consumption coolant. For example, a docked element consumes more of the substance transmitting thermal energy than the one that comes from the boiler. In this situation, it is necessary either to increase the power and circulation in the main circuit, which will not be economically feasible, as it will increase the load on the equipment, or to install a hydraulic valve to regulate the flow.

In those heating schemes that include heated floors, boilers and several circuits, the hydraulic arrow will remove any negative impact of these elements on each other. You can freely disconnect and connect any part of the structure without fear of disturbing the balance of the entire system.

If several circuits depart from one boiler, each of which has a circulation pump. Under such circumstances, the hydraulic gun will not allow counteraction from these components. The devices will operate softly, evenly distributing the coolant, which will be sufficient for each element.

A hydraulic arrow is indispensable when combining several boilers into one heating system.

In a situation where it is necessary to leave the entire system in working order, with the exception of one circuit. The hydraulic arrow provides this opportunity and, therefore, increases the maintainability of the entire heating system.

In cases where the equipment is subject to temperature changes. If a device with a higher temperature is exposed to cold liquid, the latter may crack and fail. The greatest sensitivity to such effects is shown by cast iron batteries, heat exchangers and so on. This situation can happen during an emergency shutdown, startup of the heating system, or during repair work. The hydraulic arrow will prevent thermal shock and save important parts of the entire heating system.

In addition to the above main functions of the hydraulic gun, it also has the ability to clean the heating system from decay products - scale, dirt, rust, sand, etc. For this purpose, the hydraulic separator is equipped with a valve in its lower part. In addition, the hydraulic valve can act as an air vent, thanks to a special valve in its upper part. Consequently, these capabilities of the hydraulic arrow directly have a positive impact on the reliability and safety of the entire heating system.

What types of hydraulic arrows can there be in the heating system of a private house?

Depending on the number of pipes, the following designs of hydraulic arrows can be determined:

A hydraulic arrow with 4 pipes provides 2 circuits.

KV series hydraulic arrow with 2 pipes on one side and 8 or 10 pipes on the other.

The manifold hydraulic arrow has many pipes for the possibility of connecting its own heating branch to each of them, as well as for connecting its own circulation pump to such branches.

The location of the pipes relative to each other is:

On one axis.

Offset in the form of alternating pipes (the outlet is located below the inlet).

In the latter case, the coolant will move more slowly, which will lead to better cleaning of it from air and impurities. When the pipes are located on the same axis, the coolant speed is higher, as a result of which parts of the debris can enter the second circuit.

Devices may differ in power and volume. If you know the characteristics of the boiler, then choosing the right one will not be difficult. By volume they are:

Small, up to 20 l.

Medium, up to 150 l.

Large, up to 300 l.

What are the advantages and disadvantages of a hydraulic arrow in the heating system of a private house?

Let's highlight positive properties hydraulic arrows:

Creating a uniform direction of heat energy between the return and supply pipelines;

Possibility to use pumps with relatively low power, which has a beneficial effect on installation and maintenance costs;

Reducing hydraulic loads in the heating system pipeline;

Increasing the service life of thermal installations;

Removing air from the coolant.

The hydraulic separator has no obvious disadvantages. To the question: “Is a hydraulic arrow needed in a heating system?” the answer is mostly positive. But it is worth noting that this polypropylene device still has certain disadvantages.

The disadvantages of the hydraulic gun are:

Impossibility of use with a solid fuel boiler;

If the boiler has high power, then the period of use of the hydraulic gun will be significantly reduced.

What is the principle of operation of a hydraulic arrow in a heating system

The hydraulic arrow can be designated as an intermediary between the boiler or stove and the entire heating system. The operation of the hydraulic separator is as follows:

The coolant enters the hydraulic separator, changing direction and speed. This is necessary to create a movement in which the hot flow goes up and the cold flow goes down. In turn, this process creates a thermal separation within the water gun for all circuits connected to it. For example, boilers have a high temperature, heated floors have a low temperature, and boilers are characterized by average values ​​of this indicator.

Coolant high temperature, getting into the hydraulic arrow, reduces the rate of heat distribution. This leads to the release of air, which must be removed from the heating system using a special valve located at the top of the device. It can be either manual or automatic. A Mayevsky tap is usually used as a manual valve (also called a mechanical valve). In some models, a hydraulic arrow for complex heating systems is installed at the bottom of a faucet to remove dirt and debris.

The hydraulic arrow has three operating modes:

Mode 1

In this mode, the heating system works flawlessly. The coolant pressure generated by the pump in the smaller circuit is equal to the total pressure in the remaining circuits of the system. The inlet and outlet temperatures have the same values. Working fluid either does not move vertically at all, or this movement is minimal.

However, as practice shows, ideal work situations are extremely rare. As noted above, the functioning of heating circuits is prone to fluctuations and changes.

Mode 2

In a smaller circuit, the fluid flow is not as high as in the heating circuit. In this case, demand exceeds supply, which leads to the formation of a vertical flow from the return pipe to the supply pipe. During its rise, this flow mixes with hot liquid coming from the heating device.

Mode 3

The situation is absolutely the opposite of mode 2. In this case, the coolant flow in the heating circuits is less than this figure in the small circuit. This happens for several reasons:

A short shutdown of one or more circuits due to the lack of need for heating any room;

During the heating process of the boiler, when all circuits are connected in turn;

Repair of one of the circuits in which this element is disabled.

These situations are not critical, since a downward flow of a vertical direction is formed in the hydraulic arrow.

What parameters are used to select a hydraulic arrow in the heating system of a private house?

There are only two parameters by which you can select a hydraulic gun:

Power. To determine this parameter, it is necessary to add up the thermal power of the heating system circuits. The power of the hydraulic arrow must be equal to the total power of the boilers included in this system. It will not be a problem if this indicator of the hydraulic separator is higher, but a device with a lower power is unacceptable. For example, a device with a parameter of 100 kW is suitable for a system of 85, 90 or 95 kW. But if the total boiler rating is 105 kW, then you need to choose another hydraulic pump with greater productivity.

The total volume of coolant passed through.

Why is low vertical speed important in a hydraulic gun?

Reason #1

The main reason is that a low vertical velocity allows more debris to settle. Dirt, sand, and rust will accumulate in the hydraulic arrow after some time. Consequently, this element of the heating system is also used as a sludge storage tank.

Reason #2

Creation of natural convection of coolant in the heating system. In other words, the cold flow will go down, and the hot flow will go up. This process is necessary when using a hydraulic arrow to obtain the required pressure from the temperature gradient. For example, you can make a secondary circuit for a heated floor, the temperature in which will be lower than the main one. Or get a higher temperature for an indirect heating boiler, which will intercept the greatest temperature difference, which will allow you to heat the water faster.

Reason #3

Reduction of hydraulic resistance in the hydraulic arrow. This resistance in itself is close to zero, but if you remove the first reasons, then it becomes possible to make a hydraulic separator as mixing unit. The diameter of the hydraulic needle will be reduced, and the vertical speed in it will be increased. This method provides significant savings on materials and can be used when a temperature gradient is not needed. Thus, only one heating circuit will be installed.

Reason #4

Removing air from the heating system through an air vent.

How to calculate the hydraulic arrow of a heating system using the formula

The hydraulic arrow for any heating system is selected or manufactured taking into account two parameters:

Number of pipes (calculated based on the number of circuits);

Diameter (or area) cross section housings.

S = G / 3600 ʋ, where:

S – pipe cross-sectional area, m2;

G – coolant flow, m 3 /h;

ʋ – flow velocity, taken equal to 0.1 m/s.

Such a low flow rate of the coolant is explained by the need to ensure a zone of zero pressure. As the speed increases, the pressure will also increase.

Coolant consumption can be determined based on the required thermal power consumption of the heating system. If you plan to use an element with a round cross-section, then calculating the diameter of the hydraulic arrow will not be difficult. To do this, you need to take the formula for the area of ​​a circle and determine the size of the pipe:

D = √ 4S/ π

If you decide to assemble the hydraulic arrow yourself, then you need to pay attention to the location of the pipes on it. In order not to place them haphazardly, you need to calculate the distance between the taps based on the diameter of the pipes being mounted. To do this, you can use one of the following methods:

Three diameter method;

Alternating pipe method.

Hydraulic arrow in the heating system of a private house and its step-by-step do-it-yourself installation

To make a hydraulic arrow, you can use a metal pipe or container. This will reduce costs, especially if you can do the welding work yourself (semi-automatically). You can also contact experienced specialist. After making the hydraulic arrow, it needs to be insulated.

Step 1. Take necessary tools and spare parts

You will need:

Welding machine (argon);

Profiled pipe of the required diameter;

Air release plug;

Plug for sludge removal;

Branch pipes (at least 4).

Step 2. Weld the top and bottom bottom

Since the hydraulic arrow is made from a pipe or tank, the pipes and the bottom must be welded on both sides using argon welding. It is important to consider that the quality of work must be at high level. It is also advisable to use a drawing, even if made by hand, but indicating the necessary parameters.

Step 3. Divide the hydraulic separator capacity

The container for the hydraulic arrow must be divided into several components:

The distance from the bottom to the lower pipes should be 10-20 cm. This is where rust, scale, sand and other debris will collect.

The distance from the top of the device to the upper nozzle should be approximately 10 cm.

The upper inlet and outlet pipes must be at a distance regulated by the temperature gradient. They can be either at the same level or with a shift. The higher the outlet pipe is located, the higher the operating temperature in it.

If the outlet pipe is located below the inlet pipe, then the hot flow will enter it after the entire volume has been completely heated. With this arrangement, you will get a smooth heating system. If the upper nozzles are located on the same axis, this will lead to the formation of a direct flow with weak air separation, which may lead to the occurrence of air jams.

It is important to pay attention to the location of the upper inlet pipe. It should not be at the highest point, as this prevents the movement of the hot flow. Thus, there will be no mixing of cold and hot water, which will make the installation of a hydraulic arrow pointless.

Step 4. Checking the device

The device is checked upon completion of the welding work. To check, all holes are hermetically sealed, except one, through which water is drawn into the hydraulic arrow. After filling, the last hole is also sealed hermetically, and the hydraulic arrow is left for a day. This method allows you to detect the absence of leaks.

Installing a hydraulic arrow in a heating system: 5 general rules

It doesn’t matter at all how the hydraulic arrow will be fixed - it can be fixed both vertically and horizontally. The angle of inclination is also not important. It is only necessary to take into account the direction of the end pipes. The operation of the air vent and the ability to clean sludge depend on their location.

The hydraulic arrow is mounted immediately after the boiler shut-off valves.

The installation location is selected depending on the heating system layout. However, it is important to remember that the hydraulic separator must be installed as close to the boiler as possible. For collector circuit The hydraulic arrow is installed in front of the boiler.

If it is necessary to connect an additional pump, then the hydraulic arrow is installed between the pump and the outlet pipe leading to the heating device.

When using a solid fuel boiler, the hydraulic arrow is connected to the output-input. This method helps to select the optimal and individual temperature for each component of the system.

Unusual solutions regarding the hydraulic valve in the heating system of a private house

As a rule, hydraulic arrows are made from iron pipes or steel. However, not everyone wants to use iron devices in their heating system, which clog the entire system with rust. On top of that, find the pipes large diameter made of plastic or stainless steel is not so simple.

In such conditions, a lattice-like structure made of small-diameter pipes can help. Such a design can actually be made from pipes and pipes of a similar diameter, using tees for connections. For example, a 32mm camera would be suitable. metal-plastic pipe. It can also be done from copper pipe, but polypropylene is suitable only under conditions of low operating temperature, up to 70 degrees.

An easier and cheaper way would be to install a radiator. However, this will lead to heat loss if thermal insulation is not performed.

How much will a hydraulic arrow cost in the heating system of a private house?

Due to the fact that the vast majority of hydraulic arrows industrial production equipped with a sludge separator, air vent and thermal insulation, their cost is largely determined by the place of manufacture and additional capabilities.

The price of a device made in Germany, depending on additional elements, can be in the range of 17-156 thousand rubles.

Water guns for heating systems made in Italy have an average price range from 17 to 40 thousand.

Prices for hydraulic separators domestic producers start from 3,200 rubles and rarely exceed 40 thousand.

The SantechStandard company offers wide choose devices for heating systems, and also delivers to your city. For more than 10 years, SantekhStandard has been successfully operating in the market plumbing equipment. The products offered by the company are distinguished by high-tech performance and comply international standards quality. The company's consultants will select the most optimal option for you, and will also tell you in detail about the delivery of the selected equipment. You just need to contact us by phone:

In order to equalize the hydraulic pressure in the heating system and reduce the pressure on the boiler, a hydraulic separator or, more simply put, a hydraulic arrow is used. This device is a piece of round or square section, with pipes welded to it. General form Such a device can be seen in the figure below.

What does a hydraulic arrow look like for a heating system?

As can be seen from the figure, on one and the other side there are pipes for connecting pipes from the boiler and from the heating system circuits. At the top there is usually an automatic valve for releasing air, and at the bottom there is a tap for discharging sediment from the heating system.

Usage

Typically, a hydraulic separator is installed in the following cases:

1. If the house has a large, powerful heating system with a large number of radiators, but at the same time with a small water circuit of the heating boiler. If such a system operates without a hydraulic valve, then, firstly, it is very difficult to balance, if at all possible, and secondly, a large load is created on the heating boiler pump, which quickly disables it.
2. If the heating system is combined from several circuits: radiators, heated floors, indirect heating boiler. In such heating systems without a hydraulic separator, when one circuit is turned off, an imbalance of the heating system may occur with a sharp increase in the temperature of the coolant. This also adversely affects the operation of the boiler.
3. When using two or more heating boilers in a heating system to link them into one heating system.

By installing a hydraulic arrow in the heating system, you can get the following positive changes:

1. Uniform heating of all radiators of the heating system. With good correct balancing, you can set the optimal thermal regime in the heating system.
2. Coordinated operation of water floor circuits, heating batteries and an indirect heating boiler.
3. The ability to remove accumulated dirt and excess air in the heating system. With a drain valve and automatic air valve on the hydraulic arrow you can remove various slag from the heating system.
4. It is possible to coordinate the operation of two boilers without using complex, bulky equipment.

Disadvantages of using a hydraulic gun:

1. The need to work only on heating systems with forced circulation coolant;
2. It is necessary to install an additional circulation pump on each circuit.

The hydraulic arrow in the heating system is installed strictly vertically so that sediment collects at the bottom and air leaves the heating system at the top.

Design and principle of operation

The diagram of an industrial hydraulic separator is shown in the figure below.

Hydraulic separator device

In the figure, the movement of water from the boiler is shown by a red arrow. Water entering the hydraulic switch goes around the dividing plate (2) and enters through the air exhaust channel (3) to the flow straightener (4). To remove excess air from the water, the design provides an automatic air vent (1). To control the water temperature in the hydraulic arrow, a thermometer is installed in the sleeve (5). The further movement of water into the system is shown by the red arrow. The blue arrow shows the reverse movement of water from the system to the boiler. Through the separating plates (6) the water is mixed in the hydraulic arrow. At the bottom of the hydraulic arrow there is a dirt collector with plates (7). Dirt is drained from the hydraulic arrow using a tap (9).

As can be seen from the figure, the design is not so complicated, and therefore there are no special requirements for operation. You just need to monitor the operation of the automatic air vent and dump the accumulated dirt from the hydraulic arrow.

The connection diagram and operating modes of the hydraulic arrow are shown in the figure below.

Diagram of hydraulic gun operating modes

The figure shows three main options for the operation of the hydraulic arrow. As can be seen from the figure, in the first case, the heating system consumes less coolant than the heating boiler produces. At the same time, in the hydraulic arrow there is a downward movement of water, in the direction of water movement in the boiler circuit. This situation can occur if, for example, thermal valves operate in the heating system, which restrict the flow of water. In the second case, the coolant flow rates of the heating system and the boiler are the same, and the heating operates in optimal mode. In this case, no movement of water along the hydraulic arrow is observed. The third option is when the heating system flow rate is greater than the boiler flow rate. In this case, the water in the hydraulic arrow moves upward.

Manufacturing schemes

Industrially manufactured water guns are not cheap and many people make them with their own hands. In this case, you need to make preliminary calculations. The main design dimensions are shown in the figure below.

Hydraulic switch diagram with main design dimensions

As can be seen from the figure, the diameter of the hydraulic needle itself is taken equal to three diameters of the inlet pipes, so the calculations come down mainly to determining the diameter of the hydraulic needle.

The figure shows two options for hydraulic arrows. The purpose of the second option is better than the first in that when the water passes through the supply pipeline, it is freed from air bubbles, and when it flows back, it better gets rid of sludge.

The calculation comes down mainly to determining the diameter of the hydraulic needle:

Where:

• D – diameter of the hydraulic needle in mm;
• d is the diameter of the inlet pipe in mm, usually taken equal to D/3;
• 1000 – conversion factor meters to mm;
• P – boiler power in kJ;
• π – pi number = 3.14;
• C – heat capacity of the coolant (water – 4.183 kJ/kg C°);
• W – maximum vertical speed of water movement in the hydraulic arrow, m/s, usually taken equal to 0.1 m/s;
• ΔT – difference in coolant temperatures at the inlet and outlet of the boiler, C°.

The calculation can also be performed using the following formula:

• Q – coolant flow, m³/s;
• V – speed of water movement in the hydraulic arrow, m/s;

There is also the following formula to calculate the diameter of the hydraulic needle:

• G – flow rate, m³/hour;
• W – water speed, m/s;

The height of the hydraulic arrow can be any and is limited only by the height of the ceiling in the room.

If you make the diameter of the hydraulic arrow large enough, you can get two in one: a hydraulic arrow and a heat accumulator, the so-called capacitive separator.

Diagram of a capacitive separator in a heating system

As can be seen from the figure, a hydraulic arrow of this type has a large volume, about 300 liters or more, therefore, in addition to performing its main task, it is also capable of accumulating heat. The use of a hydraulic arrow of this type is especially justified when heating with a solid fuel boiler, as it can smooth out temperature fluctuations in the heating boiler and retain the thermal energy of the boiler after the end of combustion for quite a long time.

You need to know some nuances when using this type of hydraulic arrow:

1. Firstly, such a hydraulic arrow must be insulated, since otherwise it will heat the boiler room and not transfer heat to the heating system.
2. The boiler will produce less power. This is explained by the fact that a high coolant temperature is required, and the boilers are equipped with automatic equipment that will automatically reduce its power to reduce the outlet temperature.

Hydraulic arrow for several circuits

For heating multiple circuits there are different designs hydraulic separators.

Scheme of using a hydraulic arrow in a heating system with several circuits

As can be seen from the figure, in this design, water flows from the boiler to the hydraulic switch and returns to it through two pipes, and is discharged into the system through several. This connection diagram allows you to separate the heating circuits and supply water with a different temperature gradient to each circuit.

If you make a device according to this principle, then during its operation the following will happen:

1. Hot water from the pipe (T1) will be absorbed by the pipe (T2), at a flow rate of Q1=Q2.
2. If Q1=Q2 the water entering the pipe (T3) becomes equal in temperature to the temperature of the pipes (T6), (T7), (T8), and the temperature difference between (T3) and (T4) is not significant.
3. If Q1=Q2+Q3 0.5, the following happens: temperature T1=T2, T3=(T1+T5)/2, T4=T5.
4. If Q1=Q2+Q3+Q4, then T1=T2=T3=T4.

As you can see, this connection scheme has a number of disadvantages and cannot separate the heating circuits qualitatively with the required temperature gradient.

In order to correctly distribute the temperature along the circuits, use the following connection diagram:

Hydraulic arrow diagram for correct temperature distribution along the circuits

When powered according to this scheme, it is necessary to observe certain conditions for proper operation devices:

1. The pipeline (T1) must be located above the pipeline (T2).
2. Pipe (T9) must be located exactly in the middle between pipes (T3) and (T4).
3. The pipeline (T10) and (T5) must be located at a distance of at least 20 cm from each other.
4. The pipe (T5) must be located above the pipes (T6), (T7) and (T8) so that the water coming from these pipes is mixed before entering the pipe (T5).
5. The distance between pipes (T2), (T3) and (T4) should be as equal as possible.

With this operating scheme, the temperature in the circuits can be equalized using balancing valves on pipelines (T1), (T9) and (T10). This is especially good for a boiler that needs to supply the highest coolant temperature to the lowest-temperature underfloor heating.

Instead of balancing valves, since they are too expensive, conventional valves with modulating control can be used.

You can also connect the circuits using the following collector circuit:

Collector diagram for connecting a hydraulic arrow

With this connection scheme, the temperature pressure is also regulated balancing valves, but not to the same extent as in the previous scheme. In this case, the diameter of the collectors must be large enough to distribute the coolant evenly.

Hydraulic gun designs

If when using a hydraulic arrow the goal is not to remove sludge and air from the heating system, then you can position it horizontally according to the following scheme:

Scheme horizontal arrangement hydraulic guns

As can be seen from the figure, here the hydraulic arrow is located horizontally, and the pipes, accordingly, can be either from below or from the side. In this case, the length of the hydraulic needle and the distance between the pipelines can be anything, it is only desirable that the supply and discharge pipes be located at a distance of at least 20 cm from each other.

Typically, a hydraulic separator is made of metal, but if you don’t want rust to get into the system, you can make it from polypropylene yourself. Moreover, if there are no polypropylene pipes suitable diameter, then the structure can be given the following form:

Hydraulic arrow made of plastic pipes

It can be made even easier if you install a heating radiator instead of this design. At the same time, it needs to be insulated so that it does not transfer heat to the boiler room. Otherwise, heat loss will occur.

When using a hydraulic arrow in a heating system, the following improvements in operation can be achieved:

1. The durability of the boiler increases. When working without a hydraulic valve, you can often observe temperature jumps in the system, which has a bad effect on the operation of the boiler.
2. Ability to adjust the temperature on each individual circuit.

Purpose of the hydraulic gun. Video

The video below tells about the device, purpose and operating principle of the hydraulic gun.

The hydraulic separator is considered one of the most good decisions to regulate the heating system. Despite its disadvantages, such as, for example, the need to use additional pumps and the inability to operate in free-flow mode, the use of a hydraulic arrow in a heating system has a number of advantages. It copes best with the distribution of hydraulic resistance and temperature gradient in the heating network, and it can be made with your own hands from available materials. This cannot be said, for example, about three way valve, for the production of which you need at least lathe. And subsequent operating costs are kept to a minimum. So the hydraulic separator can be considered one of the best means to regulate the heating system according to the price/functionality ratio.

In contact with

Often, on the pages of Internet resources, you can find a very concise description, written only in technical terms. hydraulic guns. In this article we will try to reveal what is a hydraulic arrow and why is it needed?.

Hydroarrow— used for hydraulic separation of flows. Thus, a hydraulic separator is a kind of channel between the circuits, which allows you to create dynamically independent circuits for transmitting movement from the coolant. Most often used on the Internet official name: hydraulic arrow —hydraulic separator.

Why do you need a hydraulic arrow in a heating system?

In a heating system, the hydraulic arrow is the connecting link between two separate heat transfer circuits and it completely neutralizes the dynamic influence between the circuits. She has two purposes:

• first, it eliminates the hydrodynamic influence, when turning off and turning on some circuits in the heating system, on the entire hydrodynamic balance. For example, when using radiator heating, underfloor heating and boiler heating, it makes sense to separate each flow into a separate circuit to eliminate influence on each other.()
• secondly, with a small coolant flow rate, it should receive a large flow rate for the second, artificially created circuit. For example, when using a boiler with a flow rate of 40 l/min, the heating system produces a flow rate 2-3 times greater (consumes 120 l/min). In this case, it is advisable to install the first circuit as the boiler circuit and install the heating decoupling system as the second circuit. In general, it is not economically feasible to accelerate the boiler more than is provided by the boiler manufacturer; in this case, the hydraulic resistance also increases, it either does not give required consumption, or increases the load of fluid movement, this leads to increased energy consumption of the pump.

On what principle does the hydraulic arrow work?

Coolant circulation in the primary circuit is created using the first pump. The second pump creates circulation through the hydraulic valve in the second circuit. Thus, the coolant is mixed in the hydraulic arrow. If the flow rate in both circuits is the same, then the coolant freely penetrates from circuit to circuit, creating, as it were, a single, common circuit. In this case, no vertical movement is created in the hydraulic arrow or this movement is close to zero. If the flow rate in the second circuit is greater than in the first circuit, then the coolant moves from bottom to top in the hydraulic arrow and, with increased flow in the first circuit, from top to bottom.

And when adjusting the hydraulic needle, you need to achieve minimal vertical movement. Economic calculation shows that this movement should not exceed 0.1 m/s.

Why reduce the vertical speed in the hydraulic gun?

The hydraulic arrow also serves as a waste settler in the system; at low vertical speeds, the garbage gradually settles in the hydraulic arrow, being removed from the heating system.

Creating natural convection of the coolant in the hydraulic arrow, so the cold coolant goes down, and the hot one rushes up. This creates the required temperature pressure. When using a heated floor, you can get reduced temperature coolant, and higher for the boiler, ensuring rapid heating of the water.

Reducing hydraulic resistance in the hydraulic arrow,

The release of microscopic air bubbles from the coolant, thereby removing it from the heating system through the auto-ventilator.

How do you know when you need a hydraulic gun?

As a rule, a water gun is installed in houses with an area of ​​more than 200 sq.m., in those houses where a complex system heating. Where distribution of coolant into several circuits is used. It is advisable to make such circuits independent of others in common system heating. Hydrostrelka allows you to create a perfectly stable heating system and distribute heat throughout the house in the right proportions. When using such a system, heat distribution along the circuits becomes precise and deviations from the configured parameters are eliminated.

Advantages of using hydraulic arrows.

Protection of cast iron heat exchangers excluding thermal shock. In a conventional system, without the use of a hydraulic switch, a sharp increase in temperature is created when some branches are disconnected and the subsequent arrival of already cold coolant. The hydraulic pointer ensures constant boiler flow, reducing the temperature difference between flow and return.

The durability and reliability of boiler equipment increases due to stable operation without temperature changes.

Lack of imbalance and creation of hydraulic stability of the heating system. It is the hydraulic arrow that allows you to increase the additional coolant flow, which is very difficult to achieve by installing additional pumps.

Operating principle of a hydraulic boom video

Why do you need a hydraulic arrow?

In this article I would like to explain in a simple and accessible form the principle of operation of a hydraulic separator and dwell on the advantages of using this device. Let's first consider the following standard diagram(picture 1.

If in your diagram the number of heating circuits (consumer pumps) is not as large as in Figure 1, do not rush to close the page, in schemes with floor-standing boilers made of cast iron heat exchangers, the hydraulic arrow can perform an important function - to protect the heat exchanger from “thermal shock”.

Hydraulic boom operation

The function of the hydraulic separator, as its name suggests, is to separate the primary (boiler) circuit from the secondary (heating) circuit. When using a hydraulic diverter, the pressure delta P between the supply and return manifolds is close to zero. The delta pressure P is determined by the hydraulic resistance of the separator, which is insignificant. In addition, this value is a constant value, independent of the number of simultaneously operating pumps in the secondary circuit.

Practical experience shows that the use of a hydraulic boom is strongly recommended if, without a separator, the pressure difference between the collectors is delta P > 0.4 meters of water column.

In addition, one of the most important functions of the hydraulic switch is to protect the cast iron heat exchanger of the boiler from thermal shock. When the boiler is turned on for the first time, the heat exchanger can heat up to a high temperature in a very short period of time, while even in the shortest heating loop the coolant does not yet have time to heat up to a similar temperature. Therefore, from the return pipeline of the heating system (for example, from the return manifold, Figure 1), the “cold” coolant enters the hot heat exchanger, which leads to its premature destruction and failure of the boiler.

The use of a hydraulic arrow makes it possible to reduce the heating circuit of the boiler and ensure that the temperature difference in the supply and return pipelines does not exceed 45 degrees. WITH.

Inside the hydraulic separator, mixing of incoming and return water can occur and it can operate in three modes.

In practice, the hydraulics of the circuit never correspond to the calculated parameters, and the use of a hydraulic separator can eliminate many shortcomings.
Dimensions and calculation of the hydraulic boom

At self-production hydraulic separator, two methods are usually used to determine optimal sizes– the method of three diameters (Figure 6) and the method of alternating pipes (Figure 7).

The only size that needs to be determined when selecting a separator is the diameter of the separator (or the diameter of the supply pipes). The hydraulic separator is selected based on the maximum possible water flow in the system (cubic m/hour) and ensuring the minimum water speed in the separator and in the supply pipes. Recommended maximum speed

the movement of water through the cross section of the hydraulic separator is approximately 0.2 m/sec.

Hydraulic separator dimensions

• D – diameter of the hydraulic separator, mm;
• d – diameter of supply pipes, mm;
• G – maximum water flow through the separator, cubic meters. m/hour;
• w – maximum speed of water movement through the cross-section of the hydraulic separator, m/sec (approximate value is approximately 0.2 m/sec);
• с – heat capacity of the coolant, in this example – heat capacity of water (constant);
• P – maximum power of installed boiler equipment, kW;
• ?T is the specified temperature difference between the supply and return of the heating system, °C (assumed to be approximately 10°C).

Omitting simple mathematical calculations, we obtain the following formulas:

1) Dependence of the diameter of the hydraulic separator on the maximum water flow in the system.

Example. According to the diagram in Figure 2, after selecting the pumps, the following values ​​were obtained for maximum modes. In the boiler circuit, the water flow through each of the boilers was 3.2 cubic meters. m/hour. The total water consumption in the boiler circuit is:

3.2+3.2=6.4 cubic meters m/hour.

In the heating circuit we have:
- first zone of the heating system – 1.9 cubic meters. m/hour;
- second zone of the heating system – 1.8 cubic meters. m/hour;
- low temperature zone – 1.4 cubic meters. m/hour;
- DHW boiler– 2.3 cubic meters m/hour.
The total water flow through the heating circuit in peak mode is:

1.9+1.8+1.4+2.3=7.6 cubic meters. m/hour.

The peak water flow in the heating circuit is higher than the water flow in the boiler circuit, therefore the size of the hydraulic separator is determined by the flow in the heating circuit.

The approximate diameter of the separator was 116 mm.

2) Dependence of the diameter of the hydraulic separator on the maximum power of the installed boiler equipment.

If the pumps have not yet been selected, then you can approximately estimate the size of the hydraulic separator based on the maximum power of the installed boiler equipment, setting the temperature difference between the supply and return of the heating system to approximately 10 ° C.

Example. According to the diagram in Figure 2, two boilers will be used with a maximum power of each - 49 kW.

The approximate diameter of the separator was 121 mm.
The main advantages of using hydraulic booms

1. The selection of pumps is greatly simplified.
2. The operating mode and durability of boiler equipment is improved.
3. Protection of cast iron heat exchanger from thermal shock.
4. Hydraulic stability of the system, no imbalance.
5. If a typical wall-mounted double-circuit boiler operates on a large heating system, then the built-in pump may not be enough. Ideal option is the use of a hydraulic separator and small pumps for each zone.
6. Commercially available commercially available separators can be used as effective removers of sludge and air from the system.

Why is the coolant temperature after the arrow (hydraulic separator) less than at the inlet?

This is the most frequently asked question from people who have a hydraulic separator installed in their boiler room. This mode of operation of the hydraulic switch is described in Figure 4. The main reason is that the coolant flow rate of the boiler circuit is less than the flow rate of the heating circuits. If the temperature difference is small, you don’t have to think about this problem; if the difference is more than 10 degrees, then you need to see if the pumps are selected correctly, or try to adjust the pump flow rates using the speed switches (the pumps themselves).

Hydraulic separators for heating are literally legendary on the Internet. They are credited with many “miraculous” properties and functions. But the purpose of this article is not to debunk myths, but to explain the true purpose of this heating element and the principle of its operation. We will also tell fans of PPR systems how to calculate and install a polypropylene hydraulic arrow and whether it is possible to make it yourself.

Why do you need a hydraulic arrow?

If you plan to install a simple heating system in your home closed type, where no more than 2 are involved circulation pumps, then you definitely don’t need a hydraulic separator.

When there are three circuits and pumps, and one of them is designed to work with an indirect heating boiler, then here too you can do without a hydraulic arrow. You need to think about separating heating circuits in a situation where the diagram looks like this:

Note. Shown here are 2 boilers operating in cascade. But this is not important; there can be only one boiler.

There is no hydraulic arrow in the presented diagram, but its installation is clearly indispensable. There are 4 circuits in which the same number of pumps of different capacities operate. The most powerful of them will create a vacuum in the supply manifold, and in the return manifold - high blood pressure. When operating simultaneously, a pump with a lower capacity simply does not have enough strength to overcome this vacuum and it will not be able to take the coolant to its circuit. As a result, the branch will not function because the pumps interfere with each other.

Important. Even if the rated performance of the pumping units is the same, the hydraulic resistance of the branches will always be different. Accordingly, the actual coolant flow in each circuit is still different; it is impossible to perfectly align the system.

To eliminate the pressure difference ΔP that occurs between the collectors and to enable all pumps to safely extract required quantity coolant, a hydraulic arrow is included in the circuit. It is a hollow pipe with a design cross-section, whose task is to create a zone of zero pressure between the heat generator and several consumers. How this element works in the boiler piping circuit is described in the next section.

Boiler piping diagram

To understand how a hydraulic arrow works in a heating system with several circuits, we propose to study the diagram of its connection to the boiler, presented below:

Now both collectors are connected to each other by a jumper that equalizes the pressure in the supply and return lines. Thanks to this, as much coolant as needed will flow into each circuit. At the same time, it is important to ensure the same coolant flow on the heat generator side, otherwise its temperature on the consumer side may become unacceptably low.

The hydraulic arrow diagram (shown above) is very popular on the Internet, depicting 3 operating modes:

• the total coolant flow in the consumer circuits and on the boiler side is the same;
• heating branches are taken away large quantity water than circulates in the boiler circuit;
• the flow rate in the ring on the heat generator side is higher.

In fact, the hydraulic switch has only one operating mode, it is shown in the diagram under number 3. It is impossible to achieve the ideal mode (No. 1), since the hydraulic resistance of the consumer branches changes all the time due to the operation of the thermostats, and it is unrealistic to select pumps so precisely. You cannot act according to scheme No. 2, because then most of The coolant will circulate in a circle on the consumer side.

This will lead to a decrease in the temperature in the heating system, because not enough hot water will be mixed into the hydraulic arrow from the boiler side. To raise this temperature, you will have to turn the heat generator to maximum mode, which does not contribute to the stable operation of the system as a whole. This leaves option No. 3, in which a sufficient amount of water at the required temperature flows into the collectors. And to reduce it in the circuits is the task of three-way valves.

There is only one function of the hydraulic arrow in the heating system - creating a zone with zero pressure, from which any number of consumers can draw coolant. The main thing is to ensure the necessary flow from the heat source. To do this, the actual performance of the boiler pump should be slightly greater than the sum of the costs for all consumer branches. All the nuances are described in more detail and shown in the video:

Manufacturing diagram of a hydraulic arrow with a manifold

Before you buy a hydraulic gun or start making it yourself, it won’t hurt to study the structure of this element. It is very simple: a hollow tube of round or rectangular section equipped with several pipes on different sides for connection to the heating network. Moreover, the pipes for connecting the supply are located, as a rule, in the upper part of the pipe, and the return pipes are located in the lower part.

Note. The specified connection method is relevant when vertical installation hydraulic arrows. At the same time, it can also be installed in a horizontal position.

Most often, a hydraulic separator is used for heating, the design of which involves the installation of a collector. They are even sold as one set, and are made from the following materials:

• low carbon steel;
• stainless steel;
• made of polypropylene.

There are more complex models, equipped not only with an air vent and drain fitting, but also with sleeves for connecting control devices and sensors, as well as various meshes and plates. They serve to clean the coolant and separate flows. A similar hydraulic gun, whose device is shown in the drawing, has a decent cost and requires periodic maintenance:

Among home craftsmen, it is customary to make a hydraulic arrow from metal pipe, but due to the considerable popularity and low cost of polypropylene, this trend is changing. After all, even an element made from PPR together with a collector costs a lot of money. Therefore, more and more often people prefer to make a polypropylene separator at home rather than buy it in a store. For this you need PPR pipe of the appropriate diameter, tees according to the number of future pipes and 2 plugs.

Since the diameter of the pipe for making a hydraulic arrow is quite large, you will need to purchase welding machine appropriate nozzle, and allow a sufficient period of time when soldering. In principle, there is nothing complicated, the tees are connected to each other by pipe sections, and plugs are placed at the ends. Another thing is that such a separator may not look very aesthetically pleasing, and it cannot be used in every system.

The fact is that solid fuel heat generators can often reach their maximum operating mode, at which the water temperature is close to 90-95 °C. Of course, polypropylene will withstand it, but in an emergency situation (for example, when the electricity is turned off), the supply temperature can jump sharply to 130 °C. This happens due to the inertia of solid fuel boilers, so all piping to them, including the water gun, must be metal. Otherwise, disastrous consequences await you, as in the photo:

Calculation of hydraulic arrow

The separator for any heating system is selected or manufactured according to 2 parameters:

• number of pipes for connecting all circuits;
• diameter or cross-sectional area of ​​the housing.

S = G / 3600 ʋ, where:

• S – pipe cross-sectional area, m2;
• G – coolant flow, m3/h;
• ʋ—flow velocity, assumed to be 0.1 m/s.

For reference. Such a low speed of water flow inside the hydraulic separator is due to the need to provide an area of ​​almost zero pressure. If the speed is increased, the pressure will also increase.

The coolant flow rate is determined earlier based on the required thermal power of the heating system. If you decide to pick up or buy an item round section, then calculating the diameter of the hydraulic needle based on the cross-sectional area is quite simple. We take the school formula for the area of ​​a circle and determine the size of the pipe:

While doing the assembly homemade hydraulic gun, it is necessary to place the pipes at a certain distance from each other, and not at random. Based on the diameter of the connected pipes, calculate the distance between the taps using one of the diagrams:

Conclusion

When planning to install a hydraulic divider, it is important to understand when it is needed and when it is not. After all, such equipment will significantly increase the cost of installing your system. As for the idea of ​​installing or making a hydraulic arrow from polypropylene, it must be understood that it is impossible to use it together with a solid fuel boiler. Soldering it from pipes and PPR tees is not difficult for a specialist.