Hydraulic arrow for heating systems. What is a hydraulic arrow for heating: functions and calculation methods Is a hydraulic arrow needed in an open heating system

While creating autonomous system One of the most important heating problems is always the careful balancing of its operation. It is necessary to ensure that all devices and components act, so to speak, “in unison”, so that each of them fully copes with its specific task, but at the same time, its functioning does not have a negative impact on others. This task looks very difficult, especially in the case when a complex, branched heating system is created, with many final heat exchange circuits.

Often such circuits have their own thermostatic control circuits, their own temperature gradient, and they differ significantly in both throughput and the required level of coolant pressure. How to connect such diversity into a single system that would work as a single “organism”? It turns out that there is a fairly simple and very effective solution. This is a hydraulic separator, or as it is more often called, a hydraulic arrow for heating systems.

This publication will discuss why it is needed, how it is designed and how it works, and what advantages it provides. For the most inquisitive readers, information is provided that allows you to independently calculate the hydraulic needle.

What is the purpose of the hydraulic arrow of the heating system?

It will be much easier to understand the purpose of the hydraulic separator if we consider the operation of the autonomous heating system of the building, starting with the simplest circuits and gradually complicating them.

So, the simplest heating system with forced circulation of coolant.

Of course, this image, and the subsequent diagrams, are presented with significant simplification - some important elements heating systems (for example), which are not important specifically for considering the purpose of the hydraulic separator.

TO– heating boiler;

R– heating radiators or other high-temperature heat exchange devices (convectors). Shown in the singular, “collectively” - in reality, of course, their number may be different. IN in this case it is important that they are all placed on one closed loop.

N– a pump that circulates the coolant through the general heating circuit.

Correct selection of the circulation pump, taking into account the required thermal power heating system, the length of the circuits and the features of heat exchange devices, allows us to ensure stable, balanced operation of the entire circuit without any additional components.

(It should be immediately noted that in some cases, even in such a simple scheme, the installation of a hydraulic switch is also required - this will also be discussed below in the text).

How to choose the right circulation pump for a heating system?

A system with forced circulation always stands out due to its flexibility in terms of adjusting operating modes, in matters of economy and operational efficiency. The main thing is that its technical characteristics are correct. More details about this can be found in a special article on the portal.

The heating circuit shown above is good for small house. But if the building is large, and even has two or more levels, then the complexity of the system increases significantly.

In such cases, it is usually used collector circuit connecting various circuits. To the common collector ( Cl) can be connected:

R– the same high-temperature circuits with radiators, and there may be several such circuits, of varying length, branching and with a different number of heat exchange devices.

STP– systems of water “warm floors”. And here there are completely different requirements for the level of coolant temperatures, that is, high-quality regulation is necessary to ensure admixture from the “return”. The length of laid “warm floor” pipes can be many times greater than the length of high-temperature circuits, that is, the level of hydraulic resistance will also be significantly higher.

Bgvs– this abbreviation marks the boiler indirect heating, which ensures the operation of an autonomous hot water supply system. And again - completely different requirements for ensuring coolant circulation through it. In addition, control of water heating in a boiler is most often done by turning this circulation on and off.

Even a reader inexperienced in such matters should have a natural doubt - will a single pump be able to cope with this entire versatile system? Apparently not. Even if you purchase a model with increased performance, the problem will not be solved. In addition, this will negatively affect the operation of the boiler - overestimate the parameters permissible flow rate and pressures set by the manufacturer - this means reducing the durability of expensive equipment.

In addition, each of the connected circuits also differs in its own performance and required pressure. That is, there will be no consistency in simultaneous functioning.

It would seem that the solution is obvious - to equip each of the circuits with a “personal” circulation pump, which, according to its characteristics, would meet the specific requirements of a particular section of the system.

But it turns out that such a measure does not solve the issue at all. On the contrary, differences in the parameters of individual circuits further aggravate the imbalance of such a circuit, and considerable problems can arise in other manifestations.

In order for all circuits to work correctly, precise coordination of all installed circulation pumps is required. And this is impossible to achieve, if only for the consideration that in such systems with quantitative and qualitative regulation of the heating level, the current productivity and pressure are variable values.

For example, there is a certain stability in the operation of the system. But at some point, maximum heating is reached on one of the underfloor heating circuits. Adjusted thermostatic valve blocks to a minimum or even completely closes the flow of coolant from the outside, from the collector, and circulates in a closed circle. Another similar example is when heated water was taken from the hot water supply system, instead cold water entered the tank, and the pump of this circuit was automatically started to compensate for the drop in temperature in the boiler.

The pump located in the boiler piping ( Nk), which will be primarily affected by all this “tatteredness” of the system, is unlikely to last long. And what’s even worse is that such surges will cause absolutely unnecessary frequent cycles of starting and stopping the boiler itself, which will significantly reduce its service life as specified by the manufacturer.

The manifold acts as a separator for the hydraulic systems of each of the system circuits. What if we also “give autonomy” to the boiler circuit? That is, to come to a position in which the boiler created the required volume of heated coolant, but each of the circuits could take exactly as much as required in this moment.

This is a completely feasible task if you select a “small” boiler circuit from the general scheme. This is precisely the function that is performed by the hydraulic separator, which is otherwise called a hydraulic arrow (in the diagram - HS). This name, apparently, was assigned to it by analogy with railway switches - it is capable of redirecting coolant flows in the direction needed at the moment.

The design of a conventional hydraulic separator is extremely simple. This is a small round or rectangular section, plugged at the ends, into which pairs of pipes are embedded - for connection to the boiler and separately - to the manifold (or directly to the heating circuit).

In essence, two (or more) completely independent circuits are formed. Yes, they are interconnected in terms of heat transfer, but each of them maintains its own circulation, optimally suited for specific conditions at the current moment in time. That is, both the flow rate (let’s call it conventionally Q) of the coolant and the created pressure (N) - in each of the separated circuits - are their own.

As a rule, the performance indicators in the boiler circuit are stable (Qк) - the circulation pump operates in the specified optimal mode, the most “gentle” for the boiler equipment. The cross-section of the separator itself ensures minimal hydraulic resistance in the “small” circuit, which makes the circulation in it completely independent of the processes that are currently occurring in other parts of the heating system. This mode of operation of the boiler, without pressure surges, without multiple frequent start-up and stop cycles, is the key to its many years of trouble-free operation.

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How does a hydraulic arrow function in a heating system?

Three main operating modes of the hydraulic separator

If we do not take into account various intermediate options, the operation scheme of the hydraulic gun can be comprehensively described by three main modes of its operation:

Mode one

The system is practically in equilibrium. The flow rate of a “small” boiler circuit practically does not differ from the total flow rate of all circuits connected to the manifold or directly to the hydraulic valve ( Qк =Qо).

The coolant does not linger in the hydraulic arrow, but passes through it horizontally, creating virtually no vertical movement.

Coolant temperature at the supply pipes ( T1 And T2) – is the same. Naturally, the same situation applies to the pipes connected to the “return” ( T3 And T4).

In this mode, the hydraulic gun, in fact, has no effect on the functioning of the system. But such an equilibrium position is an extremely rare phenomenon, which can be noticed only occasionally, since the initial parameters of the system always tend to change dynamically - the entire system of its thermostatic regulation is based on this.

Mode two

At the moment, it has turned out that the total flow rate on the heating circuits exceeds the flow rate in the boiler circuit ( Qк< Qо).

It is a completely normal situation, quite often encountered in practice, when all circuits connected to the collector at this very moment require maximum coolant flow. In ordinary words, the immediate demand for coolant exceeded what the boiler circuit could produce. The system will not stop or become unbalanced. It’s just that in the hydraulic arrow, a vertically ascending flow will form on its own from the “return” pipe of the manifold to the supply pipe. At the same time, this flow in the upper region of the hydraulic separator will be mixed with hot coolant circulating along the “small” circuit. Temperature balance: T1 > T2, T3 = T4.

Mode three

This mode of operation of the hydraulic separator is, in fact, the main one - in a well-planned and correctly installed heating system, it will be the one that will prevail.

The coolant flow rate in the “small” circuit exceeds the same total indicator on the collector, or, in other words, the “demand” for the required volume has become lower than the “supply”. ( Qк >Qo).

There may be many reasons for this:

— Thermostatic control equipment on the circuits has reduced or even temporarily stopped the flow of coolant from the supply manifold to the heat exchange devices.

— The temperature in the indirect heating boiler has reached its maximum, and the intake hot water It hasn’t happened for a long time - the circulation through the boiler has stopped.

— Disabled for some time or for a long period separate radiators or even circuits (the need for maintenance or repair, there is no need to heat temporarily unused rooms and other reasons).

— The heating system is put into operation in stages, with the gradual inclusion of individual circuits.

None of the above reasons will have any negative impact on the overall functionality of the heating system. The excess coolant volume will simply go into the “return” of the small circuit in a vertical downward flow. In fact, the boiler will provide a slightly excess volume, and each of the circuits connected to the manifold or directly to the hydraulic arrow will take exactly as much as is currently required.

Temperature balance under this operating mode: T1 = T2, T3 > T4.

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Prices for hydraulic arrows for heating systems

hydraulic arrow for heating

Additional features of the hydraulic gun

In addition to the operating modes mentioned above, the hydraulic gun is capable of performing several more useful functions.

After entering the main cylinder of the hydraulic separator, due to a sharp increase in volume, the flow rate drops. This promotes the settling of insoluble suspensions that may appear in the coolant during its movement through pipes and radiators. A tap is often mounted at the bottom of the hydraulic valve to periodically drain accumulated sediment from the system.
The same reason - a sharp decrease in flow speed, also makes it possible to separate gas bubbles from the liquid. It is clear that the system usually includes air vents in the safety group and Mayevsky valves on the radiators, but an extra separator will never hurt, especially at the outlet of the boiler, where gas formation during high-temperature heating cannot be completely eliminated.

Manufacturers of heating equipment even provide special meshes inside the main cylinder when making hydraulic separators - this way the separation is more efficient. Well, in this case, an automatic air vent is installed on top of the hydraulic arrow.

At the beginning of the article it was said that even in the simplest system heating water gun can play a useful role. This applies to systems equipped with boilers with a cast iron heat exchanger.

Despite all the advantages of cast iron, this metal has an “Achilles heel”: due to its fragility, it does not like mechanical or thermal shocks. A sharp change in temperature, when there is cold water at the entrance to the heat exchanger, and in the area exposed to flame the indicators are many times higher, can lead to the appearance of cracks. This means that this critical period of “acceleration” should be minimized.

This is where the hydraulic separator helps. Heating a small volume in a “small” circuit when starting the system will not take much time. Then you can sequentially open circulation in the remaining heat exchange ducts.

It is interesting that some manufacturers of boiler equipment with cast iron heat exchangers directly address this issue in the operating instructions. Connecting such a boiler directly to the collector may well entail a refusal by the manufacturer to fulfill its warranty obligations.

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Main parameters of the hydraulic separator

So, we have seen that the fundamental design of a hydraulic separator is extremely simple. True, the discussion was and will continue to be mainly about the “classical” layout of this element of the system - a vertical cylinder with side pipes. The fact is that in the assortment of shops and craftsmen there are often more complex models, for example, immediately combined with a collector. True, this does not change in any way either the operating principle or the basic dimensional proportions of the separator.

Despite the simplicity of the device, the parameters of the hydraulic separator must still meet certain requirements. And if a skilled house owner, who has good plumbing and welding skills, is going to make a hydraulic arrow on his own, he should know what to start from.

Attention! All pipe diameters listed below are not external diameters, but internal ones, that is, nominal diameters!

The “classic” layout of a conventional hydraulic arrow is based on the “rule of three diameters”. That is, the diameter of the pipes is three times smaller than the diameter of the main cylinder of the separator. The nozzles are located diametrically opposite, and their placement along the height of the hydraulic arrow is also tied to the base diameter. This is shown more clearly in the diagram below:

Some changes in the location of the pipes are also practiced - a kind of “ladder”. In this case, the diagram takes the following form:

This change is mainly aimed at more effective removal gas and insoluble precipitate. When moving along the supply pipe, a slight change in the direction of the coolant flow in a zigzag downward manner contributes to a more quality removal gas bubbles. On the reverse flow, on the contrary, the step is upward, and this makes it easier to remove solid inclusions. And besides, this arrangement contributes to better mixing of flows.

Where did these proportions come from? They are selected to ensure a vertical flow velocity (upward or downward) in the range from 0.1 to 0.2 meters per second. This threshold cannot be exceeded.

The lower the vertical flow speed, the more effective the separation of air and sludge will be. But that's not even main reason. The slower the movement, the better and more complete the mixing of flows with different temperatures occurs. As a result, a temperature gradient is formed along the height of the hydraulic needle, which can also be “put into service.”

If the heating system includes circuits with different temperature conditions, then it makes sense to even use a hydraulic arrow, which will act as a collector, and different pairs of pipes will have their own temperature pressure. This will significantly reduce the load on thermostatic devices, making the entire system more manageable, efficient and economical.

For lovers self-made– below is the recommended assembly diagram for such a hydraulic arrow with three different temperature outputs to the heating circuits. The closer the pair of pipes is to the center, the lower the temperature difference in the supply pipe, and the smaller the temperature difference in the supply and return. For example, for radiators optimal mode– 75 degrees in supply with a difference Δt = 20 ºС, and for heated floors 40÷45 with Δt = 5 ºС will be sufficient.

If you look through publications about heating systems, you will notice that horizontal hydraulic separators are also used. In such options, of course, there is no question of air or sludge separation. And the location of the pipes can differ significantly - for effective convection of the coolant, schemes are often used even in the opposite direction of the flows of the “small” and heating circuits. Some similar examples shown in the illustration:

If desired, such a hydraulic separator can be made, for example, for reasons of more compact placement of equipment in the boiler room. The counter direction of flows, by the way, makes it possible to slightly reduce the diameter of the pipes. But at the same time, some design requirements must be met:

— Between the pipes of the same circuit (no matter which), a distance of at least 4d must be maintained.

— When applying the first rule, it should be borne in mind that if the inlet pipes have a diameter of less than 50 mm (and this happens very often), then in any case the distance should not be less than 200 mm.

Concluding the consideration of the design of the hydraulic needle, we can add the following. Home craftsmen often make such devices even from polypropylene pipes. At the same time, they deviate from the “canons” of the layout and create a separator, for example, in the form of a lattice. With this approach, it is quite possible to make a hydraulic arrow from pipes with a diameter of 32 mm. True, in terms of mixing quality similar design will be inferior to the single-hull.

You can also find completely “exotic” designs. So, one of the craftsmen installed two sections of a conventional cast-iron heating radiator as a hydraulic switch. There are no words - such a device will cope with the task of hydraulic flow separation. But such an approach will also require very reliable thermal insulation of the device, otherwise it will experience completely unproductive heat loss.

Calculation of parameters of a “classical” hydraulic arrow

The schemes proposed above are wonderful. But here's how to accurately determine the specific values of these very D And d?

We offer two calculation options. The first is based on the power of the heating system. The second is on the performance of circulation pumps installed in the boiler circuit and in all heat exchange circuits.

We will not bore the interested reader with a series of formulas. It is better to invite him to use the capabilities of the online calculators located below, which will make the necessary calculations quickly and accurately. The result will be shown in millimeters - the recommended minimum internal diameters of pipes for the manufacture of the hydraulic arrow itself and the pipes for connecting the circuits. Next, in accordance with the diagrams proposed above in the publication, it remains to determine the remaining dimensions.

Calculator for calculating hydraulic separator parameters based on boiler power

In the data entry fields you must indicate:

Speed of vertical flow movement.
Maximum design power of the heating system.
Temperature operating conditions of the “small” circuit, that is, the temperature level in the supply and “return” directly near the heating boiler.

Designing your own heating system is far from easy. Even if the installers “plan” it, you need to be aware of many nuances. Firstly, to monitor their work, and secondly, to assess the need and feasibility of their proposals. For example, in recent years, hydraulic arrows for heating have been intensively promoted. This is a small addition, the installation of which costs a considerable amount. In some cases it is very useful, in others you can easily do without it.

What is a hydraulic arrow and where is it installed?

The correct name for this device is a hydraulic arrow or hydraulic separator. It is a piece of round or square pipe with welded pipes. There is usually nothing inside. In some cases there may be two grids. One (above) for better “discharge” of air bubbles, the second (bottom) for screening out contaminants.

In the heating system, the hydraulic arrow is placed between the boiler and consumers - heating circuits. It can be positioned both horizontally and vertically. Most often they are placed vertically. With this arrangement, an automatic air vent is installed at the top, and a shut-off valve at the bottom. Some of the water with accumulated dirt is periodically drained through the tap.

That is, it turns out that a vertically installed hydraulic separator, at the same time as its main functions, removes air and makes it possible to remove sludge.

Purpose and principle of operation

A hydraulic arrow is needed for branched systems in which several pumps are installed. It provides the required coolant flow for all pumps, regardless of their performance. That is, in other words, it serves for hydraulic decoupling of the heating system pumps. That’s why this device is also called a hydraulic separator or hydraulic separator.

A hydraulic arrow is installed if the system has several pumps: one on the boiler circuit, the rest on the heating circuits (radiators, water floor heating, indirect heating boiler). For correct operation, their performance is selected so that the boiler pump can pump a little more coolant (10-20%) than is required for the rest of the system.

Why do you need a hydraulic arrow for heating? Let's look at an example. In a heating system with several pumps, they often have different capacities. It often turns out that one pump is many times more powerful. All pumps have to be installed nearby - in the manifold unit, where they are hydraulically connected. When powerful pump turns on full power, all other circuits remain without coolant. This happens all the time. To avoid such situations, they install a hydraulic arrow in the heating system. The second way is to spread the pumps over a long distance.

Operating modes

Theoretically, three modes of operation of a heating system with a hydraulic arrow are possible. They are shown in the figure below. The first is when the boiler pump pumps exactly the same amount of coolant as required by the entire heating system. This is an ideal situation in real life very rare. Let's explain why. Modern heating adjusts its operation according to the temperature of the coolant or the temperature in the room. Let's imagine that everything was calculated perfectly, the valves were tightened, and after adjustment, equality was achieved. But after some time, the operating parameters of the boiler or one of the heating circuits will change. The equipment will adapt to the situation, and the equality of productivity will be violated. So this mode can last a matter of minutes (or even less).

The second mode of operation of the hydraulic switch is when the flow rate of the heating circuits is greater than the power of the boiler pump (middle picture). This situation is dangerous for the system and should not be allowed to happen. This is possible if the pumps are selected incorrectly. Or rather, the boiler pump has too low a capacity. In this case, to ensure the required flow rate, coolant from the return line will be supplied to the circuits along with the heated coolant from the boiler. That is, at the boiler outlet, for example, 80°C, into the circuit after adding cold water is coming eg 65°C (actual temperature depends on the flow deficit). After passing through the heating devices, the temperature of the coolant drops by 20-25°C. That is, the temperature of the coolant supplied to the boiler will be best case scenario 45°C. If we compare it with the output temperature - 80°C, then the temperature delta is too high for a conventional boiler (not a condensing boiler). This mode of operation is not normal and the boiler will quickly fail.

The third operating mode is when the boiler pump supplies more heated coolant than the heating circuits require (right figure). In this case, part of the heated coolant is returned back to the boiler. As a result, the temperature of the incoming coolant rises, and it operates in a gentle mode. This is the normal operating mode of a heating system with a hydraulic arrow.

When is a hydraulic arrow needed?

A hydraulic arrow for heating is 100% needed if the system will have several boilers operating in a cascade. Moreover, they must work simultaneously (at least most of the time). Here, for correct operation, a hydraulic separator is the best solution.

If there are two simultaneously operating boilers (in cascade), a hydraulic arrow is the best option

Another hydraulic arrow for heating can be useful for boilers with a cast iron heat exchanger. In the hydraulic separator tank, warm and cold water. This reduces the temperature delta at the boiler outlet and inlet. This is a blessing for a cast iron heat exchanger. But a bypass with a three-way adjustable valve will cope with the same task and will cost much less. So even for cast iron boilers located in small heating systems, with approximately the same flow rate, it is quite possible to do without connecting a hydraulic arrow.

When can I deliver

If the heating system has only one pump - on the boiler, a hydraulic arrow is not needed at all. You can get by if one or two pumps are installed per circuit. Such a system can be balanced using control valves. When is the installation of a hydraulic arrow justified? When the following conditions exist:

There are three or more circuits, all of very different power (different circuit volumes, different temperatures required). In this case, even with perfectly accurate selection of pumps and calculation of parameters, there is a possibility of unstable operation of the system. For example, a situation often occurs when the radiators get cold when the floor heating pump is turned on. In this case, hydraulic isolation of the pumps is needed and therefore a hydraulic arrow is installed.
In addition to radiators, there is a water-heated floor that heats large areas. Yes, it can be connected through the manifold and mixing unit, but it can force the boiler pump to work in extreme mode. If your heating pumps often burn, you most likely need to install a hydraulic arrow.
In a medium or large volume system (with two or more pumps), you are going to install automatic control equipment - based on coolant temperature or air temperature. At the same time, you don’t want/can’t adjust the system manually (with taps).

In the first case, a hydraulic decoupling is most likely needed, in the second, it is worth thinking about installing it. Why just think? Because these are significant expenses. And it’s not just the cost of the hydraulic gun. It costs about $300. I'll have to put more optional equipment. At a minimum, you need manifolds at the inlet and outlet, pumps for each circuit (with a small system, you can do without them), as well as a pump speed control unit, since they can no longer be controlled through the boiler. Combined with the installation fee for the equipment, this “add-on” amounts to approximately two thousand dollars. Quite a lot indeed.

Why then install this equipment? Because with a hydraulic arrow, heating works more stable and does not require constant adjustment of the coolant flow in the circuits. If you ask the owners of cottages whose heating is made without a hydraulic separator, they will tell you that they often have to reconfigure the system - turn the valves, adjusting the flow of coolant in the circuits. This is typical if used various elements heating. For example, there is a warm floor on the ground floor, radiators on two floors, heated utility rooms, in which it is necessary to support minimum temperature(garage, for example). If you expect to have approximately the same system, but the prospect of “adjustment” does not suit you, you can install a hydraulic arrow for heating. If it is available, each circuit receives as much coolant as it requires at the moment and does not in any way depend on the operating parameters of nearby pumps in other circuits.

How to select parameters

The hydraulic separator is selected taking into account the maximum possible coolant flow rate. The fact is that at high speeds of liquid movement through the pipes, it begins to make noise. To avoid this effect, the maximum speed is assumed to be 0.2 m/s.

Parameters required for the hydraulic separator

By maximum coolant flow

To calculate the diameter of the hydraulic arrow using this method, the only thing you need to know is the maximum coolant flow that is possible in the system and the diameter of the pipes. With pipes everything is simple - you know which pipe you will use for wiring. We know the maximum flow that the boiler can provide (it is in the technical specifications), and the flow rate through the circuits depends on their size/volume and is determined when selecting circuit pumps. The flow rate for all circuits is added up and compared with the power of the boiler pump. A large value is substituted into the formula to calculate the volume of the hydraulic needle.

Let's give an example. Let the maximum flow rate in the system be 7.6 cubic meters/hour. The permissible maximum speed is taken as standard - 0.2 m/s, the diameter of the pipes is 6.3 cm (2.5 inch pipes). In this case we get: 18.9 * √ 7.6/0.2 = 18.9 * √38 = 18.9 * 6.16 = 116.424 mm. If we round, we find that the diameter of the hydraulic needle should be 116 mm.

According to the maximum boiler power

The second method is to select a hydraulic needle according to the boiler power. The estimate will be approximate, but it can be trusted. The boiler power and the difference in coolant temperatures in the supply and return pipelines will be needed.

The calculation is also simple. Let maximum power boiler - 50 kW, temperature delta - 10°C, pipe diameters are the same - 6.3 cm. Substituting the numbers, we get - 18.9 * √ 50 / 0.2 * 10 = 18.9 * √ 25 = 18.9 * 5 = 94.5 mm. Rounding, we get the diameter of the hydraulic needle 95 mm.

How to find the length of the hydraulic arrow

We have decided on the diameter of the hydraulic separator for heating, but we also need to know the length. It is selected depending on the diameter of the connected pipes. There are two types of hydraulic arrows for heating - with taps located one opposite the other and with alternating pipes (located offset from one another).

Determining the length of the hydraulic arrow from a round pipe

It is easy to calculate the length in this case - in the first case it is 12d, in the second - 13d. For medium-sized systems, you can select the diameter depending on the pipes - 3*d. As you can see, nothing complicated. You can calculate it yourself.

Buy or make it yourself?

As they said, a ready-made hydraulic arrow for heating costs a lot - $200-300 depending on the manufacturer. To reduce costs, there is a natural desire to do it yourself. If you know how to cook, no problem - we bought the materials and did it. But the following points must be taken into account:

The thread on the bends should be well cut and symmetrical.
The walls of the outlets are of the same thickness.

The quality of a homemade product may be “not very good”

It seems like obvious things. But you will be surprised how difficult it is to find four normal fittings with normally made threads. Next, everything welds must be of high quality - the system will work under pressure. The bends are welded strictly perpendicular to the surface, at the required distance. In general, this is not such an easy task.

If you don’t know how to do it yourself, you’ll have to look for a performer. It’s not at all easy to find: either they charge a lot for the services, or the quality of the work is, to put it mildly, “not very good.” In general, many people decide to buy a hydraulic gun, despite the considerable cost. Moreover, in Lately, domestic manufacturers make no worse, but much cheaper.

Hydroarrow. Operating principle, purpose and calculations.

A complete list of information about hydraulic guns

How I envy you that you got here and are reading this article. I didn't find it on the Internet detailed explanation hydraulic arrows and other hydraulic separators.

Therefore, I decided to do my own investigation into the principles of operation of the hydraulic separator. And dispel stupid arguments and calculations about hydraulic arrows.

Video about the purpose of the hydraulic arrow

Video: Tee hydraulic arrow - calculation of diameters/flow rates of the hydraulic arrow

This is a complete list of information on how to understand the operation of the hydraulic switch and make calculations. I will also tell you how to understand the popular formula for calculating the hydraulic arrow and you will understand how much you can deviate from the calculations in order to understand the effectiveness of the hydraulic arrow. Let's solve the problem from real example. Let's consider the physical laws applicable to hydraulic arrows.

In this article you will learn:

This article is not plagiarism by copying other people's calculations and other people's recommendations!!!

And so let's get started!!! I explain qualitatively and in in simple language, for Dummies.

To understand how a hydraulic arrow works, we will touch on hydraulics and heating engineering. With the help of hydraulics, we will understand how water moves in a hydraulic arrow. And with the help of heat engineering, we will understand how heated water passes and is distributed.

As a hydraulic engineer, I propose to consider any heating system through many connecting tubes capable of passing a certain flow of water inside itself. For example, in this pipe there is such and such a flow rate, in another pipe there is a different flow rate. Or in this ring (circuit) - there is one flow rate in another ring - another flow rate is produced.

Parting words for future specialists

In order to correctly consider a heating system, it is necessary to consider the system as a system of forming rings in which some kind of flow occurs. Based on the flow rate, it will be possible to calculate, and the flow rate also gives us an accurate translation of how much heat is required to be transferred through the pipe by the coolant. You will also need to understand the difference in pressure on the supply and return pipelines. I’ll write about this in other articles sometime, on the qualitative calculation of heating system circuits.

About the forms of the hydraulic arrow:

In section:

As you can see, there is nothing complicated inside. There are, of course, all sorts of modifications with filters. Maybe in the future some Uncle Vanya will come up with more complex structures, but for now we will study such hydraulic arrows. According to the principle of operation, round hydraulic arrows are practically no different from profile hydraulic arrows. Rectangular (profile) hydraulic arrow, more beautiful than better working. From a hydraulic point of view, a round hydraulic arrow is better. A profile hydraulic arrow rather reduces the location in space and increases the capacity of the hydraulic arrow. But all this does not affect the parameters of the hydraulic guns.

Hydroarrow- serves for hydraulic separation of flows. That is, the hydraulic separator is a kind of channel between the circuits and makes the circuits dynamically independent when transmitting the movement of the coolant. But at the same time it transfers heat well from one circuit to another. Therefore, the official name of the hydraulic gun is: Hydraulic separator.

Purpose of the hydraulic arrow for heating systems:

First appointment. Receive at low coolant flow - high flow in the second artificially created circuit. That is, for example, you have a flow rate of 40 liters per minute, but the flow rate turned out to be two to three times higher - for example, flow rate = 120 liters per minute. The first circuit will be the boiler circuit, and the second circuit will be the heating decoupling system. It is not economically feasible to accelerate the boiler circuit to a flow rate greater than that provided by the boiler manufacturer. Otherwise, it will increase, which either will not provide the required flow rate, or will increase the load on the movement of the fluid, which will lead to additional pump consumption for electricity.

Second appointment. Eliminate the hydrodynamic influence of turning on and off certain circuits of heating systems on the overall hydrodynamic balance of the entire system. For example, if you have, radiator heating and a hot water supply circuit (indirect heating boiler), then it makes sense to divide these flows into separate circuits. So that they do not influence each other. Let's look at the diagrams below.

Hydroarrow is a connecting link between two separate heat transfer circuits and completely eliminates the dynamic influence of the two circuits among themselves.

There is no dynamic or hydrodynamic influence in the hydraulic arrow between the circuits- this is when the movement (speed and flow) of the coolant in the hydraulic arrow is not transmitted from one circuit to another. This means: The influence of the pushing force of the moving coolant is not transferred from circuit to circuit.

See image simple example. Further schemes will be more complicated.

This is a simplified diagram designed to understand the essence of the hydraulic arrow. Pumps that can or should be installed on a cooled return pipeline to increase their service life. However, there are factors that deliberately force pumps to be installed on a hot supply pipeline. From a hydraulic point of view, it is better to install the pump on the supply pipeline, since the hot liquid has minimal viscosity, which increases the flow rate of the coolant through the pump. I'll write about this someday.

Pump H 1 creates a flow rate in the primary circuit equal to Q 1. Pump N 2 creates a flow rate in the second circuit equal to Q 2.

Principle of operation

Pump H 1 creates coolant circulation through the hydraulic arrow along the primary circuit. Pump H 2 creates coolant circulation through the hydraulic arrow along the second circuit. Thus, the coolant is mixed in the hydraulic arrow. But if the flow rate is Q 1 =Q 2, then mutual penetration of the coolant occurs from circuit to circuit, thereby, as it were, creating one common circuit. In this case, vertical movement in the hydraulic needle does not occur or this movement tends to zero. In cases where Q 1 >Q 2, the movement of the coolant in the hydraulic arrow occurs from top to bottom. In cases where Q 1

When calculating the hydraulic arrow, it is very important to obtain a very slow vertical movement in the hydraulic arrow. The economic factor indicates a speed of no more than 0.1 meters per second, for the first two reasons (see below).

Why is the required low vertical speed in the hydraulic gun?

First, main reason low speed is to allow floating debris (crumbs of sand, sludge) to settle (fall down) in the system. That is, over time, some crumbs gradually settle in the hydraulic arrow. The hydraulic arrow can also serve as a sludge storage tank in the heating system.

The second reason- this is an opportunity to create natural convection of the coolant in the hydraulic arrow. That is, to allow the cold coolant to go down and the hot coolant to rush up. This is necessary in order to use the hydraulic arrow as an opportunity to obtain the required temperature pressure from the temperature gradient of the hydraulic arrow. For example, for a heated floor, you can get a secondary heating circuit with a lower coolant temperature. Also, for an indirect heating boiler, you can get a higher temperature, which will be able to intercept the maximum temperature pressure in order to quickly heat water for hot consumption.

Third reason- this is to reduce the hydraulic resistance in the hydraulic arrow. In principle, it is already reduced, almost to zero, but if you omit the first two reasons, you can make the hydraulic arrow like. That is, reduce the diameter of the hydraulic needle and increase the vertical speed of the hydraulic needle, make it more - increased. This method saves on materials and can be used in cases where a temperature gradient is not needed and only one circuit is obtained. This method significantly saves money on materials. Below I will present a diagram.

Fourth reason- this is to separate microscopic air bubbles from the coolant and release them through.

In what cases is a hydraulic gun necessary?

I’ll describe it approximately, for dummies. Typically, a hydraulic arrow is located in a house whose area exceeds 200 square meters. Where available a complex system heating. This means that the coolant distribution is divided into many circuits. Contour data that should be made dynamically independent of common system heating. A system with a hydraulic arrow becomes an ideally stable heating system in which heat is distributed throughout the house in precise proportions. In which deviation of proportions in heat transfer is excluded!

Can a hydraulic arrow stand at an angle of 90 degrees to the horizontal?

To put it simply, it can! It's right asked question half the answer! If you omit the first two reasons (described above), then you can safely rotate it as you want. If it is necessary to accumulate sludge (dirt) and release air automatically, then it must be installed as expected. And also if it is necessary to divide the circuits according to temperature indicators.

Calculation of hydraulic arrow

There is a very popular calculation on the Internet for calculating hydraulic arrows, but the principle of each variable figure is not explained. Where did this formula come from? There is no evidence for this formula! As a mathematician, I am very concerned about the origin of the formula...

And I will clarify all the details for you...

In particular, the simplest method is:

Three diameter method and alternating pipe method

I will tell you how these two types of hydraulic guns differ, and which is better. And is it worth resorting to any option or is it all the same. More on this below.

And so let’s break this formula down piece by piece:

The number (1000) is the conversion of the number of meters to millimeters. 1 meter = 1000 mm.

And now, taking a step-by-step look at all the nuances that affect the diameter of the hydraulic needle...

In order to calculate the diameter of the hydraulic needle, you need to know:

Let's take this image as an example:

The flow rate of the primary circuit will be the maximum flow rate supplied by pump H1. Let's take 40 liters per minute.

Remember that the solution will come in handy.

The flow rate of the second circuit will be the maximum flow rate released by the H2 pump. Let's take 120 liters per minute.

The maximum possible vertical speed of the coolant in the hydraulic arrow will be a speed of 0.1 m/s.

To calculate the diameter, remember these formulas:

Hence the diameter formula:

To maintain the speed in the hydraulic arrow, simply insert V = 0.1 m/s into the formula

As for the flow rate in the hydraulic arrow, it is equal to:

Q = Q1-Q2 = 40-120 = -80 liters/min.

Let's get rid of the minus! We don't need him. And that Q=80l/min.

We translate: 80 l/min = 0.001333 m 3 /sec.

Well, how do you like the calculation? We found the diameter of the hydraulic arrow without resorting to temperature and thermal values; we don’t even need to know the boiler power and temperature changes! It is enough to know only the flow rates of the circuits.

Now let’s try to understand how we came to calculate this formula:

Let's consider the formula for finding the boiler power:

Inserting into the formula we get:

ΔT and C, according to the rules of mathematics, are reduced or mutually destroyed, since they are divided into each other (ΔT/ ΔT, C/C). What remains is Q - flow rate.

You don't have to specify the coefficient 1000 - this is the conversion of meters to millimeters.

As a result, we came to this formula [V=W]:

Also on some sites there is the following formula:

[3 d] is economic indicator found experimentally. (This indicator is for dummies who are too lazy to count). Below I will provide calculations for all diameters.

The number (3600) is the conversion of speed (m/s) from the number of seconds to hours. 1 hour = 3600 seconds. Since the flow rate is indicated in (m 3 / hour).

Now let's look at how we found the number 18.8

Volume of the hydraulic arrow?

Does the volume of the hydraulic arrow affect the quality of the system?

Of course, it does, and the more it does, the better. But what is it better for?

In order to equalize temperature jumps for!

An effective volume for equalizing temperature surges will be a volume of 100-300 liters. Especially in a heating system where there is a solid fuel boiler. A solid fuel boiler, unfortunately, can produce very unpleasant temperature jumps for.

Have you imagined such a hydraulic gun in the form of a barrel?

If not, then look at the image:

Capacitive hydraulic separator- this is a hydraulic gun in the form of a barrel.

Such a barrel serves as a kind of heat storage device. And creates a smooth temperature change in the second circuit. Protects the heating system from solid fuel boiler, which is capable of sharply increasing the temperature to a critical level.

The laws described below are partially applicable to small-volume hydraulic shooters (up to 20 liters).

The role of the hydraulic arrow in modern heating systems

In order to find out what a hydraulic arrow is and what functions it performs, first we will get acquainted with the features of the operation of individual heating systems.

Simple option

The simplest version of a heating system equipped with a circulation pump will look something like this.

Undoubtedly, this scheme significantly simplified, since many elements of the network in it (for example, the security group) are simply not shown in order to “make the picture easier to understand.” So, in the diagram you can see, first of all, a heating boiler, thanks to which the working fluid is heated. Also visible is a circulation pump, through which the liquid moves through the supply (red) pipeline and the so-called “return”. Typically, such a pump can be installed both in the pipeline and directly in the boiler (the latter option is more typical for wall-mounted devices).

Note! There are also heating radiators in the closed circuit, thanks to which heat exchange occurs, that is, the generated heat is transferred to the room.

If the pump is correctly selected in terms of pressure and performance, then it alone will be quite sufficient for a single-circuit system, therefore, there is no need to use other auxiliary devices.

More complex option

If the area of the house is large enough, then the diagram presented above will clearly not be enough for it. In such cases, several heating circuits are used at once, so the diagram will look slightly different.

Here we see that through the pump, the working fluid enters the manifold, and from there it is transferred to several heating circuits. The latter include the following elements.

A high temperature circuit (or several), in which there are collectors or ordinary batteries.
DHW systems equipped with an indirect heating boiler. The requirements for the movement of working fluid are special here, since the temperature of water heating in most cases is regulated by changing the flow rate of the fluid passing through the boiler.
Warm floor. Yes, the temperature of the working fluid for them should be an order of magnitude lower, which is why special thermostatic devices are used. Moreover, the contours of the heated floor have a length significantly exceeding the standard wiring.

It is quite obvious that one circulation pump cannot cope with this kind of load. Of course, today high-performance models with increased power are sold, capable of creating enough high pressure, however, it is worth thinking about the heating device itself - its possibilities, alas, are not limitless. The fact is that the boiler elements are initially designed for certain pressure and performance indicators. And these indicators should not be exceeded, as this can lead to breakdown of the expensive heating installation.

In addition, the circulation pump itself, operating at the limit of its capabilities in order to supply all circuits of the network with liquid, will not be able to last long. What can we say about the loud noise and consumption? electrical energy. But let's return to the topic of our article - to hydraulic arrow for heating.

Is it possible to install one pump per circuit?

It would seem quite logical to equip each heating circuit with its own circulation pump that meets all the necessary parameters in order to solve the problem. Is it so? Unfortunately, even in this case the problem will not be solved - it will simply move to another plane! Indeed, for the stable functioning of such a system, an accurate calculation of each pump is necessary, but even with this, a complex multi-circuit system will not become equilibrium. Each pump here will be associated with its own circuit, and its characteristics will change (that is, they will not be stable). In this case, one of the circuits can fully operate, and the second can be turned off. Due to circulation in one circuit, inertial movement of the working fluid may occur in an adjacent circuit, where this is not required at all (at least for the moment). And there can be a lot of such examples.

As a result, the underfloor heating system may overheat unacceptably, different rooms may be heated unevenly, individual circuits may become “locked.” In a word, everything is happening to ensure that your efforts to equip the system with high efficiency go down the drain.

Note! This especially affects the pump installed next to the heating boiler. And in many homes, several heating devices are used at once, which are extremely difficult, almost impossible, to control. Because of all this, expensive equipment simply fails.

Is there a way out? Yes - not only divide the network into circuits, but also take care of a separate circuit for the heating boiler. And we’ll help you with balancing the hydraulic valve for heating, or, as it is also called, the hydraulic separator.

Features of the hydraulic separator

So, this simple element needs to be installed between the collector and the heating boiler. Many will ask: why was this device even called an arrow? The reason, most likely, is that it can redirect the flow of working fluid, due to which the entire system is balanced. From a constructive point of view, this hollow pipe, which has a rectangular or circular cross-section. This pipe is plugged on both sides and is equipped with two pipes - an outlet and, accordingly, an inlet.

It turns out that a pair of interconnected circuits appear in the system, which at the same time do not depend on each other. The smaller circuit is intended for the boiler, and the larger one is designed for all branches, circuits and the collector. The flow rate for each of these circuits is different, as is the speed of movement of the working fluid; in this case, the contours do not have any significant influence on each other. Note also that the pressure in a circuit of a smaller volume is usually stable, since the heating device permanently operates at the same speed, while a similar indicator in a larger circuit may change depending on the current operation of the heating network.

Note! The diameter of the work must be selected so that a zone of low hydraulic resistance is formed, allowing the pressure in the smaller circuit to be equalized, regardless of whether the working circuits are active.

As a result, each section of the system operates as balanced as possible, pressure drops are not observed, and boiler equipment functions well.

Video - Key features of hydraulic arrows for heating

Operating principle of the hydraulic arrow

In short, the hydraulic gun can operate in one of three possible operating modes. Let's take a closer look at each of them.

Situation No. 1

We are talking about an almost ideal state of equilibrium of the entire network. The fluid pressure generated by the pump in the smaller circuit is the same as the total pressure of all circuits of the heating system. The inlet and outlet temperatures are similar. The working fluid does not move vertically or moves in a minimal amount.

But it is worth noting that in reality this kind of situation is extremely rare, because the functional properties of heating circuits, as we mentioned earlier, are prone to periodic changes.

Situation No. 2

In heating circuits, the flow rate of working fluid is higher than in a smaller circuit. Figuratively speaking, demand significantly exceeds supply. Under such conditions, a vertical flow of media occurs from the return pipe to the supply pipe. This flow, rising, mixes with hot liquid, which, in turn, is supplied from the heating device. The diagram below shows the situation more clearly.

Situation No. 3

The complete opposite of the previous situation. The flow rate in a smaller volume circuit exceeds that in heating circuits. This may happen due to:

short-term shutdown of one circuit (or several at once) due to lack of demand for heating a particular room;
warming up the boiler, which involves the step-by-step connection of all circuits;
shutting down one circuit for repair purposes.

There's nothing wrong with that. At the same time, a downward flow of vertical direction appears in the heating water arrow itself.

Popular manufacturers

There are not as few companies involved in the production of hydraulic separators for heating networks as it might seem at first glance. However, today we will get acquainted with the products of only two companies, GIDRUSS and Atom LLC, since they are considered the most popular.

Table. Characteristics of hydraulic separators manufactured by GIDRUSS.

Model, illustration	Main characteristics
1. GR-40-20
2. GR-60-25	— the product is made of structural steel; — designed for one consumer; — the minimum power of the heating device is 10 kilowatts;
3. GR-100-32	— the product is made of structural steel; — designed for one consumer;
4. GR-150-40	— the product is made of structural steel; — designed for one consumer; — minimum power of the heating device is 61 kilowatts; — its maximum power is 150 kilowatts.
5. GR-250-50	— the product is made of structural steel; — designed for one consumer; — the minimum power of the heating device is 101 kilowatts; — its maximum power is 250 kilowatts.
6. GR-300-65	— the product is made of structural steel; — designed for one consumer; — its maximum power is 300 kilowatts.
7. GR-400-65	— the product is made of structural steel; — designed for one consumer; — minimum power of the heating device is 151 kilowatts; — its maximum power is 400 kilowatts.
8. GR-600-80	— the product is made of structural steel; — designed for one consumer; — minimum power of the heating device is 251 kilowatts; — its maximum power is 600 kilowatts.
9. GR-1000-100	— the product is made of structural steel; — designed for one consumer; — minimum power of the heating device is 401 kilowatts; — its maximum power is 1000 kilowatts.
10.GR-2000-150	— the product is made of structural steel; — designed for one consumer; — minimum power of the heating device is 601 kilowatts; — its maximum power is 2000 kilowatts.
11. GRSS-40-20	— minimum power of the heating device is 1 kilowatt; — its maximum power is 40 kilowatts.
12. GRSS-60-25	- the product is made of of stainless steel AISI 304; — designed for one consumer; — the minimum power of the heating device is 11 kilowatts; — its maximum power is 60 kilowatts.
13. GRSS-100-32	— the product is made of AISI 304 stainless steel; — designed for one consumer; — minimum power of the heating device is 41 kilowatts; — its maximum power is 100 kilowatts.

Note also that each hydraulic arrow for heating of the above also performs the functions of a kind of sump. The working fluid in these devices is cleaned from various kinds mechanical impurities, which significantly increases the service life of all moving components of the heating system.

Hydraulic separators produced by Atom LLC and average prices

The products of this manufacturer are also in considerable demand, and the reason for this is not only the good quality of the hydraulic guns, but also their affordable cost. You can familiarize yourself with the characteristics of the models and their average market prices from the table below.

Features of the calculation of the hydraulic separator

Why is an accurate calculation of the hydraulic needle for heating systems necessary? The fact is that thanks to this the required temperature regime, which, in turn, will achieve coherent functioning of all elements - such as a thermal head, circulation pump, heating element, and so on. For calculations, special formulas must be used to determine the optimal dimensions of the thermometer.

The essence of these calculations is extremely simple: it is necessary to find the diameter of the installation that allows the working fluid in the heating circuit to be directed to the coolant masses of the heating device. All the necessary information for doing the calculations yourself is given below.

Note! If everything is calculated incorrectly, then energy will be overused. Therefore, before purchasing a hydraulic separator, it is necessary to mandatory perform these calculations with maximum accuracy. Ideally, this should be done by a professional design engineer who has the appropriate skills.

That's all. For a more detailed understanding of the issue, we recommend that you watch the video below. Good luck!

Video - How to calculate a hydraulic arrow for heating

The hydraulic arrow, the operating principle of which is based on the protection of boiler heat exchangers, protects them from thermal shock. In this case, the basis of the system is cast iron. Often such situations arise during the initial startup of the boiler device or during technical work when you need to disconnect the circulation pump from the hot water. In addition, the use of a hydraulic separator helps maintain the integrity of the heating system in the event of a shutdown of hot water supply in automatic mode.

The hydraulic arrow in cross-section is nothing complicated. Of course, there are more complex modifications equipped with filters. Perhaps in the future even more will be invented complex design, but so far the hydraulic arrow is a unified device.

According to the principle of operation, round hydraulic separators are no different from profile ones, which have a rectangular shape. A profile hydraulic arrow, the operating principle of which is to reduce the location in space and increase the capacity, has a more attractive appearance. Hydraulic view arrow round shape fits better.

Purpose of the device

The hydraulic arrow, the principle of operation of which will be described in this article, is needed to equalize the pressure level in the boiler system at different flow rates in the main circuit and the sum of the indicators of the secondary thermal circuits. The device regulates the functioning of heating systems with multiple circuits (radiator, water heater, heated floor). Subject to proper rules in hydrodynamics, the device will ensure the absence of negative interaction of the circuits and will enable constant operation in the established mode.

The hydraulic separator plays the role of a settling tank and eliminates mechanical formations (scale, corrosion) from the coolant while complying with hydromechanical standards. This function has a very positive effect on the operating time of the moving parts of the heating system.

The device removes air from the coolant, which reduces the oxidation process in metal elements.

In systems standard design, where the presence of only one circuit is implied, turning off a number of branches leads to very low consumption in the boiler. As a result, the temperature of the cooled coolant increases significantly.

The hydraulic separator ensures the maintenance of stable heat consumption, which compares the temperatures on the supply and return pipes.

What processes occur in the hydraulic arrow

To understand the purpose of installing this device in the heating system, you need to find out what processes occur with water during the period of passage through the cavity of the hydraulic needle. It is necessary to understand the basic operating parameters of two or more autonomous circuit heating systems.
After all installation work has been completed, the joints in the pipes will be welded. The heating system is being filled cold water. As a rule, the temperature is 5-15 Cº.
When the automation turns on the main circuit pump for circulation and the burner is ignited, the secondary circuit pumps do not work, and the coolant moves only through the primary circuit. Thus, the flow will rush downward.
After the coolant reaches desired temperature, the secondary water flow circuit produces the same selection. When the water flows of the main and secondary circuits are equal, the hydraulic separator acts as an air vent. It filters out dirt and fuel oil. Thus, the process of heating and heating hot water occurs. It should be noted that achieving absolutely equal water flow rates in all circuits is an impossible task.
By means of automation, the flow rate in the secondary circuit is regulated when the water reaches the desired temperature and the hot water pump turns off. If the thermal heads of the radiators cover the flow due to overheating of the room on the sunny side, then the hydraulic resistance in this circuit of the heating system increases. In this case, an automated pump is connected, which reduces the performance and flow of water in the secondary circuits. Through the flow along the main and secondary circuits, movement begins upward along the hydraulic arrow. If the heating system is not equipped with a hydraulic arrow, then due to significant distortion in the hydraulic system, at a minimum, the pumps responsible for circulation would cease to function.
When the device stops the operation of the main heating circuit pump, the coolant flow in the hydraulic arrow rushes upward. But this situation occurs very rarely.

How to make a hydraulic arrow yourself

Many people are interested in how to make a hydraulic arrow with their own hands? To make this device you will need welding skills. It should be noted that installing a homemade system will also be expensive.

To make a device such as a hydraulic arrow with your own hands, you will need drives, taps, pressure gauges, a pipe rectangular shape, grinder, hammer and welding machine with electrodes up to 3 mm.

The holes in the collector should be burned with an electrode according to the markings. On bends for welding, a chamfer of 1 mm must be made. Welding is carried out in a circle with a leg index of 3-4 mm. Next, the collector pipes are marked. with a hydraulic arrow in this case assumes the presence of three circuits.

In the contour pipe on the “cold” side, two holes should be burned along the edges and three under the connecting pipes (two in one direction and one in the other). On the “hot” side, one hole is burned in the middle and three holes for the connecting leads. Through holes must be located on the same axis with the outlet holes on the “hot” pipe. Two outlet pipes will be welded in them, and the third will be the outlet pipe. On the “cold” side there will be two holes for connecting pipes and one designed for a pipe that passes through hot pipe in the middle of the assembly. Holes for pressure gauges are burned after preliminary assembly.

The final stage in the manufacture of such a device as a hydraulic arrow with your own hands is testing the system under water pressure.

This can be done by coating the seams with soap. A pressure of at least 2 atmospheres should be applied. It can be supplied in any way and to any point (for example, a fitting drain tap). The seams do not need to be coated if it is possible to control the pressure drop. If it falls, then covering it with soap foam will be necessary.

Do-it-yourself hydraulic arrow made of polypropylene

Currently, installing a device such as a hydraulic arrow with your own hands from polypropylene is quite possible.

The main circuit departs from the boiler. Of secondary importance is the decoupling system in the heating system. It is very uneconomical to accelerate the main boiler circuit more than provided by the device manufacturer. Hydraulic resistance increases, which increases the load on the coolant and does not provide the required flow.

A do-it-yourself hydraulic arrow made of polypropylene, with a minimum flow rate of any coolant, can create a higher flow rate thanks to a second artificial circuit.

If the house has a radiator heating system and hot water supply, then it is recommended to divide the boiler into separate circuits made of polypropylene. This way they will not influence each other.

A do-it-yourself hydraulic arrow made of polypropylene has large functionality. It acts as a link between two separate circuits that transport heat. In the absence of hydraulic and dynamic influence of the circuits on each other, the flow rate and speed of the coolant and separator do not move from circuit to circuit.

Why is the coolant temperature after the hydraulic separator lower than at the outlet?

This phenomenon can be explained by different flow rates of the circuits. High temperature enters the hydraulic arrow, which mixes with the cold coolant. The consumption rate of the latter is higher than the consumption of hot.

Why does a hydraulic gun require vertical speed?

For a device such as a hydraulic arrow, the operating principle is based on a vertical direction. There is an explanation for this.

The main reason that the vertical speed is low is the presence of rust and sand in the pipes. These new growths settle on the separator. They need to be given a chance to settle.
The low speed makes it possible to create natural convection of the coolant in the hydraulic separator. The cold flow goes down, and the hot flow rises up. The result is the desired temperature pressure.
Low speed makes it possible to reduce hydraulic resistance in the hydraulic arrow. It has a zero indicator, but if we discard the first two reasons, then the hydraulic separator can be used as a In other words, the diameter of the needle is reduced and its vertical speed increases. This makes it possible to save materials. A hydraulic arrow can be used in cases where there is no need for a temperature gradient, but only a heating circuit is required.
Low speed removes small air bubbles from the coolant.

Is it possible to install at an angle of 90 degrees to the horizontal?

The device can be installed at this angle. You can place the hydraulic arrow in any position. If it is necessary to detach mechanical waste, remove the air flow in automatic mode, or divide the circuit in accordance with the temperature indicator, the device should be installed as originally intended.

Does the volume of the arrow matter?

Of course he plays. The optimal volume indicator for equalizing temperature differences is 100-300 liters. An indicator of this volume is especially relevant if the boiler operates on warm fuel.

How to choose a hydraulic gun

The arrow has two main indicators:

power (you need to sum up the power indicators of the heat and all circuits);
total volume of pumped coolant.

It is these data that determine the performance of such a device as a hydraulic gun, the calculation of the power of which is checked against the data in the technical passport upon purchase.

How to install a hydraulic arrow

As a rule, the hydraulic separator is installed in a vertical position. But the device can also be positioned horizontally at any angle. The direction of the end pipes should be taken into account, as this is necessary for the proper functioning of the air vent and the accumulation of sediment that needs to be removed from the system.