Balancing valves and temperature controller working principle. Balancing valve: principle of operation

The heating system needs periodic adjustment. The coolant must be evenly distributed over it, which means that special equipment is required that will help make the adjustment correctly. Such a device is often a balancing valve.

By hydraulic balancing, the coolant is distributed to all sections of the heating circuit without exception.

Simple system options involve adjusting the coolant flow by selecting the optimal pipe diameter around the perimeter.

Special washers are also used, the passage in which is designed for uninterrupted water flow, and uniform heating of the elements.

Each of these options was used in old-style heating circuits. A new method is the installation of a balancing valve, which is a conventional valve that regulates the amount of coolant supply.

Design feature

A quality part includes reliable components:

• Robust brass body with threaded fittings for connecting pipes. Inside the product there is a saddle in the form of a special vertical channel.
• Adjusting spindle. The working part is represented by a cone that is screwed into the saddle. As a result of the spindle engagement, the coolant flow is blocked.
• Rubber sealing rings.
• Cap, usually made of plastic. There are also metal options.

A distinctive feature of the device is the presence of two special fittings.

They are responsible for the following functions:

1. Determine the pressure inside the system both before and after the valve.
2. Connect the capillary tube.

Each of the fittings measures the pressure, and if a difference in values ​​is detected on the control mechanism, the water flow is calculated.

Operating principle

Balancing valves are designed to use them to achieve maximum efficiency of all heating elements of the system, as well as to adjust it at any time.

Whatever the heating system, it involves setting up, which can be done in a certain way. This is necessary so that the parameters in individual sections are close to the calculated ones. Thus, it is possible to achieve work efficiency. Various means can be used for adjustment, however, the most common and modern is the balancing valve, the principle of which is presented in the article.

The need to use

Heating systems suggest the need for balancing, which is a hydraulic adjustment. The purpose of these manipulations is to bring the individual branches of the circuit to the required value, only in this way the required amount of heat will be supplied to each radiator. When it comes to simple systems, the required flow rate of the coolant is ensured with the help of correctly selected pipe diameters.

Use in complex systems

Complex systems in their work provide for adjustment with special washers, the passage size of which ensures the flow of water in the required volume. The listed methods are outdated, today a modern method is used, which is expressed in the installation of balancing valves. These devices are manual valves, with the help of which the flow of the coolant is regulated. The mechanism has an addition that blocks the flow, fittings are used for this.

Principle of operation

After you have learned what the principle of operation of which will be described below is used for, you can proceed to install the device. First you need to understand the principle. To do this, you can imagine a dead end branch that has several radiators, the latter act as energy consumers. A certain volume of coolant, heated to the design temperature, is supplied to them through pipes. It is determined depending on how much thermal energy will be needed to heat the premises.

It is used when there are no radiators and the water flow for each of them is constant. The mentioned device must be located on the return pipeline, in the place where it can be cut into a common line. This allows you to carry out the necessary measurements by setting the valve to the desired number of revolutions. A certain constant water flow in the regulated branch will be guaranteed. However, users quite often face the fact that the flow rate changes, this can happen when thermostatic regulators are installed on the radiators. They are designed to control the intensity of heating the room and create an obstacle in the way of water, reducing the volume of its flow. In this case, in the return common pipeline, the flow rate of the coolant volume will change.

For reference

A manual balancing valve will guarantee a certain volume of coolant, which will achieve the desired effect when the number of batteries is small and does not reach 5 pieces. If you limit the regulation limits of thermostats, then the existing circuit can be easily adjusted. If the number of radiators is more than mentioned, then they will go haywire. The thermostat installed on the first battery will block the flow of coolant, which will cause an increase in flow on the second radiator. The valve will close on it, the flow will go to the third radiator, and so on. Ultimately, such work will lead to the fact that some batteries will overheat unnecessarily, while others will remain cold, and the branch will be unbalanced. An automatic balancing valve must be installed on a riser or branch with a sufficiently large number of heaters, only then the system will work clearly.

The principle of operation of the valve on the riser with a large number of radiators

If an automatic balancing valve is used under the conditions described above, then the principle of operation is somewhat different. In this case, the valve is adjusted to the maximum calculated water flow. During operation, when the thermostat of any battery will reduce the consumption of hot water, the pressure in the area will increase. The automatic regulator will receive a pulse through the capillary tube, this will allow the device to respond quickly by adjusting the water flow, then the other thermostats will not have time to work, the flow will not be blocked, and the system will remain hydraulically balanced.

Classification

The balancing valve, the principle of operation of which was described above, is offered for sale in a wide range. Before you make a purchase, you must understand the classification. Thus, when choosing, it is necessary to take into account the design parameters of the system at the installation point. The master must pay attention to the maximum pressure of the working medium and the nominal parameter, and also take into account the pressure difference in the return and supply circuits.

The valve may belong to one or another class depending on the area of ​​use. Thus, the devices are used at individual construction sites, housing and communal services, in industrial facilities and on sections of main pipelines. The balancing valve, the principle of which you should know before purchasing the device, can be selected according to the type of piping system that is designed for air conditioning, hot or cold water supply, cooling or heating. Among other things, the described devices differ in the type of coolant, such as steam, water or glycol solution. By type of installation, valves are divided into fixed and adjustable.

Main types of valves

If you are interested in the MSV balancing valve, then it is offered for sale in a wide variety, among other models you can see devices with manual adjustment, with which it is easy to adjust individual sections of the system and the entire pipeline, determining the pressure and flow of the medium at control points. With the help of manual balancing valves, it is possible to turn off individual sections, freeing them from the working coolant. The main advantage is low cost, but you should pay attention to some disadvantages. Among the main ones is the ability to set the balance only for the average design parameters of direct current. With fluctuations in flow, which occurs in plumbing systems, balancing can be disturbed.

An automatic balancing valve, the price of which is 6,000 rubles, can also be automatic; it is installed on the return and inlet circuits. Another type of valve provides the ability to adjust the temperature of the working medium.

Installation Features

If you decide to purchase a Danfoss balancing valve, you should first familiarize yourself with the installation features. In order to guarantee measurement accuracy, there must be sections of pipe free of bends before and after the device. The length of the section will depend on the diameter. Before the valve, the length of the straight pipe should be equal to 5 pipe diameters, after the valve, the length should be two diameters or more. If these recommendations are not taken into account when a Danfoss balancing valve is installed, then the measurement error can reach 20%.

The problem of uneven distribution of heating in multi-circuit heating systems is quite common. The coolant flow is similar to electric current, therefore it flows along the path of minimum resistance. It turns out that the farther from the boiler, the less heat consumption is than near it. To equalize this indicator, the craftsmen use a balancing valve.

Sometimes, in order to save money, an ordinary crane is installed to adjust the level of patency, but this setting is coarser and inaccurate, while the balancing valve does its job perfectly. The choice is influenced by the result that the tenants seek to obtain. Often, craftsmen install a ball valve with a long switch and turn the lever in a different direction, which also causes inconvenience. The balancing valve device initially has special inputs that serve as flow measurements. It uses the elements of the heating system to the maximum, makes them give off all the heat, with the possibility of adjustment at any time.

Design and principle of operation

The mechanism is that the valve device changes the internal flow area. Turning the handle activates the nut and spindle. When unscrewing, the final element rises to the upper position from the lower one. If it is located in the lower part, the parts reliably block the flow, preventing the coolant from passing through the pipes. In other words, when the valve is unscrewed, the spool passes a certain amount of heat, increasing the permeability. When closed, the opening narrows, making the flow negligible.

The radiator structure required for the mechanical adjustment of the heating branches is based on the following elements:

• brass frame with threaded pipes for connecting pipes. The interior features a molded round saddle in a vertical format;
• locking and regulating spindle with a working area in the form of a frame, which enters the saddle when twisting. It determines the exact amount of water flow;
• sealing ring made of rubber;
• a cap made of metal or plastic that acts as a protector.

Main models of valves differ from radiator ones in dimensions, inclined spindle arrangement and fittings. They perform the following role:

• coolant drain;
• connection of measuring devices;
• installation of a capillary tube from a pressure corrector.

The number of revolutions from the closed to the maximum open state is from 3 to 5, this indicator is different for each manufacturer. To change the position of the stem, an ordinary or specialized key in the form of a hexagon is required.

What is the pressure difference between two points

When the master adjusts the flow rate using the balancing cock, the pressure losses on the pipes and on the valve become different, which changes the pressure drop on the balancing valves.

The calculation of this difference is worth considering with an example. So, pressure gauges are installed on the supply and return pipelines, which show the pressure level at these points. The difference will be considered the value that equates to the difference between the two pressure gauges. In other words, if one device outputs 1.5 bar and the other outputs 1.6 bar, then the difference is 0.1 bar. If the valve is automatic, it automatically corrects the difference between the points. This element always comes in pairs, since it is very important to feel the deviation.

Mechanical balancer

The manual valve works great at stable pressure. Ideal for apartments and houses with a small number of heating radiators. Simplifies repair work, because it does not need to turn off the entire heating system. Effective action is carried out in those rooms where the number of radiators does not exceed 5 units.

With a significant number of batteries, mechanical devices cause the valves to malfunction. At the moment when the thermostat on the first radiator is closed, the fluid flow on the second one increases. Then the temperature of the coolant in some batteries rises to boiling, but in others it heats up too little. Only automatic valve models can cope with such a problem.

Automatic balancer

Installation of devices is carried out on branches or risers with a large number of radiators. They differ from the first type in the principle of operation. The valve is moved to the position of maximum fluid consumption. When the coolant flow rate is reduced by the thermostat of one of the radiators, the pressure rises. Then the capillary tube mechanism begins to work, which immediately proceeds to the analysis of the pressure drop. In general, the advantages of automatic balancers are as follows:

• the presence of a capillary tube, which contributes to the instantaneous operation of the adjustment;
• the mechanism does not change the pressure level, preventing vibrations from disturbing it;
• if desired, craftsmen can create "independent regions".

The flow adjustment is carried out so quickly that the following thermostats do not yet have time to completely overlap. This ensures that the system is constantly balanced.

Applications

In private homes, mechanical models are often used. They are quite enough to heat a building up to 500 m². Installation of manual valves of the main plan is carried out in the following situations:

• in buildings with an extensive heating system with many risers;
• in multi-apartment buildings equipped with an individual boiler room;
• during tying a solid fuel boiler with an existing heat accumulator.

Radiator models are installed at the outlet of the heater, while main valves are installed exclusively in the pipeline that returns the cooled liquid to the boiler room. If the structure is mounted in tandem with an automatic valve, then it can be located both in the return and in the supply pipeline.

Steel and aluminum radiators with a bottom connection are often initially equipped with taps using specialized fittings that act as attachments for connections to such parts. The need to install valves also disappears in the following cases:

• in dead-end mechanisms of insignificant length, with identical “shoulders” in terms of hydraulics;
• when all batteries have thermostatic valves with presetting;
• on the final radiator (dead end);
• in the mechanisms of the collector plan.

Temperature controllers with presetting, mounted on the liquid supply, also cope with the work of the balance valve, due to which a shut-off ball valve can be connected at the outlet of the heating mechanism. Similarly, the armature is installed on the connections to the last battery in the chain, and since there is no need for adjustment, it must be completely open.

Installation and operation

Professionals leave a small gap in front of the valve and straight pipe. This prevents the occurrence of bends that impede the movement of water. In order to protect against the ingress of dirt and dust on the adjustment elements, a special filter is installed directly in front of the valve. The pipe itself must be washed before installation, checked for damage. Further, the installation is carried out as follows:

1. The master is determined with the area where the valve will be mounted in the future. The dimensions of the straight zones of the pipe before and after the element must correspond to the following parameters: 5 diameters in front of the part, 2 and more after it, as this eliminates turbulence.
2. The valve is screwed into the pipe, pre-equipped with tow. Threading can be done with a die or other similar tool. The main thing is that it be at least 7 turns.

The installation of the valve is easily carried out according to the principle of installing a ball valve. How exactly the valve itself is placed in space is not particularly important. The main thing is that the arrow on the body corresponds to the direction of the water flow. Otherwise, the part will contribute to fluid resistance.

How to balance the radiator network

Often, craftsmen find out the flow rate of the coolant as follows: the number of revolutions of the balancing valve is divided by the number of heating elements. In this way they calculate the adjustment step. Further, moving from the last battery to the first, the valves are twisted based on the degree of speed difference.

The calculation is approximate and takes into account the different capacities of the batteries, which is why the method is resorted to only before pre-setting during operation. Only specialists can correctly configure the device, since the process needs additional skills and knowledge. Step by step it looks like this:

1. All valves open and are brought to the working format, where the supply temperature is equal to 80 °C.
2. The temperature of all heating elements is measured.
3. The identified difference is eliminated: the taps of the first and middle batteries are slightly opened. The closest one opens by 1-1.5 turns, the second - by 2-2.5.

After 20 minutes, the master takes measurements again, since during this time there is a complete adaptation to the new settings. A perfectly tuned system has a minimum temperature difference between the nearest and farthest radiator.

Manufacturers

Today, the most famous manufacturers of balancing valves are the brands Danfoss, Herz, Caleffi, Oventrop and others. They produce products in two formats - angular and straight. The principle of their work is identical, so only the form changes. The pressure and temperature index for all manufacturers is also different. It is advisable to choose exactly the faucet that fully corresponds to the characteristics of the heating system.

The balancing valve contributes to the uniform distribution of heating in multi-circuit systems. It does not matter how far the radiator is from the boiler, as a properly adjusted valve allows heating all rooms at the same temperature.

Content

For the effective functioning of the heating system, the actual parameters of its operation must be close to the calculated values. It is important to ensure proper distribution of coolant flows along the circuits, stable pressure and temperature conditions. To solve this range of problems allows a special device - a balancing valve for the heating system.

Balancing valves used for heating systems

Purpose of the device

All branches of the heating system must receive the calculated amount of coolant. Previously, simple systems were regulated by using pipes of different diameters. In complex ones, special washers were installed, by shifting which it was possible to change the cross section of the pipeline. Today, a special valve is used that functions on the principle of a valve.

The balancing valve is equipped with two fittings, thanks to which:

• the pressure of the coolant flow is measured before and after passing through the valve;
• a capillary tube is connected to allow adjustment.

Based on the readings of the device, it is possible to determine the pressure drop during the passage of water through the regulator, and calculate, according to the instructions, how many turns of the handle are required to optimize the operation of the heating system.

Note! A number of manufacturers offer balancing valves with a digital display, but such devices are more expensive.

Principle of operation

Consider why balancing the heating system is necessary and how it happens. If several heating radiators are connected to a dead branch of the pipeline and are not equipped with thermostats, the coolant flow for each heating device will be constant. In order for each of the devices to get the required amount of heated water, a manual regulator is installed on the return line, at the point where the pipe is connected to the common line. Its valve is set to a certain number of revolutions in order to reduce or increase the diameter of the through hole.

But this option is not suitable for a system with a constantly changing coolant flow. In this case, a balancing valve is needed, the principle of which allows to reduce the volume of heated water supply by creating an obstacle in the flow path.

The manual balancer is designed to stabilize the coolant flow for 4-5 heating devices. If there are more radiators in the system, their heating will be uneven.

By setting the balancing valve for the heating system to the maximum flow rate, we get the following situation: the thermostat responsible for regulating any of the radiators will reduce the consumption of the heated coolant, as a result of which the pressure in the system will begin to gradually increase.

The balancing valve will receive a signal about the growing pressure (capillary tube is used for this) and will work, adjusting the fluid flow. Due to the fact that the thermostats on the remaining radiators do not have time to shut off the coolant supply, the pressure in the system and the coolant consumption will be balanced.

Design

Control valves vary in design. In the classic version, the device is equipped with a straight stem and a flat spool, the adjustment is due to a change in the flow area between the spool and the seat. The translational movement of the spool is provided by the rotation of the handle.

Equalizers are also produced with a rod located at an angle relative to the coolant flow, the spool can have a cone-shaped, radial or cylindrical shape, and be driven by a servo drive.

Device types

The balancing valve for the heating system, the principle of operation of which depends on the design features, can be mechanical (manual) and automatic.

Mechanical balancer

A manual balancing valve is installed instead of classic shims and similar devices. The mechanical regulator is designed to work in a system with a constant pressure of the transported medium. Using a mechanical valve, you can not only ensure the required cross-section of the pipeline, but also disconnect a separate heating device from the network, drain the coolant from it through a special tap. The manual valve is inexpensive and can be equipped with devices to measure the pressure in the system on both sides of the regulator and the actual flow rate of the transported medium.

Automatic balancer

Automatic balancing valve is a device that allows you to quickly change the operating parameters of an autonomous heating network in accordance with pressure drops and consumption of heated coolant. For each pipeline, automatic balancers are installed in pairs.

A balancer and a shut-off valve on the supply pipeline sets a limit on the flow of the coolant in accordance with the design requirements. A valve is mounted on the return line to prevent sudden pressure drops. This approach makes it possible to divide the heating system into separate sections that can function independently of each other. Pressure equalization and adjustment of the coolant supply are carried out automatically.

Applications

Balancing valve is also included:

• In a small circulation circuit of a solid fuel heating boiler, closed to a heat accumulator. The regulator makes it possible to do without installing a mixing unit to maintain the temperature of the coolant in the circuit at a level of at least 60 degrees. The balancing valve on the supply pipe ensures that the flow rate in the boiler circuit is higher than in the heating circuit.
• To regulate the operation of an indirect heating boiler. The balancer regulates the supply of heated coolant directly from the boiler to the coil installed in the tank with water for hot water supply.

Installation and operation

The installation of the balancing valve is carried out according to the requirements of the manufacturer. If there is an arrow on the body, the device is mounted in such a way that the direction of the arrow coincides with the direction of the flow of the transported medium so that the valve can create the design resistance. Some manufacturers produce balancing valves that can be installed in any direction. The spatial arrangement of the stem in most cases is not important.

To prevent the valve from failing due to mechanical damage, a branded filter or a standard sump is installed in front of it. To avoid unwanted turbulence, valves are recommended to be installed on straight sections of the pipeline, the minimum length of which is indicated in the instructions from the manufacturer.

If the heating system is equipped with automatic valves, it should be filled through special filling fittings installed next to the valves on the return pipe, while the balancing valves on the supply pipe are closed.

The balancing valve is adjusted using a table with indicators of pressure drop and coolant flow (attached to the device) or using a flow meter for balancers. But the initial calculation of the flow rate and operating parameters must be performed at the design stage of the heating system.

In order for each balancing valve in the heating system to function properly, it is advisable to give preference to products from reputable manufacturers. These include regulators manufactured under the Danfoss trademark (Denmark), the Venturi series from BROEN BALLOREX (Poland).

Conclusion

Balance valves are recommended for use on all branches of the heating system, including underfloor heating circuits, as well as in the DHW system. This will optimize their work and save energy. It is important to choose high-quality devices, correctly mount them and configure them correctly.

Older people probably remember such a natural disaster as the visit of a plumber. And as soon as he complained about the low pressure in the system, he “secretly” reported that for a small additional fee he could remove the throttle washer. Indeed, the effect of this operation was noticeable immediately. But after a week, the neighbors called the locksmith, then the neighbors from above, and after a couple of months the whole effect was already reduced to zero. This example can serve as an illustration of the importance of precisely and correctly calculated balancing of pressures and flows in the pipeline systems of multi-apartment and high-rise buildings, cottage and summer cottages.

But such balancing is of considerable importance in the water supply systems of individual private houses and cottages, creating conditions for the joint functioning of cold and hot water supply, heating and air conditioning systems, irrigation systems, baths, swimming pools, etc. And to replace the adjustment using throttle washers , which required stopping the water supply and dismantling the pipeline, modern devices came - manual and automatic balancing valves.

Even a well-designed and installed plumbing or heating system requires initial adjustment, and in the process of further operation - periodic adjustment of a uniform distribution of pressures and temperatures. For this, control valves are used: pressure reducers, bypass and balancing valves. And if outwardly they differ little from each other and from the usual shut-off valve, each of them has its own purpose. Reducers serve to limit the upper threshold of pressure in the system, bypass valves regulate the flow of flowing fluid through sections of the pipeline by redistributing it. Balancing valves are used to adjust the balance of pressures and temperatures in branched sections of the pipeline.

In the simplest case, the role of a balancing valve can be performed by an ordinary valve. The only difference is that balancing valves, produced for narrow ranges of values, can perform fine, “stretched”, adjustment exactly in the range for which this section of the pipeline is designed. In addition, they are equipped with measuring taps that allow, using special devices, to check and accurately set values ​​in all sections of the pipeline.

The use of balancing valves in heating systems plays a special role, allowing you to fine-tune the distribution of heat given off by the coolant in all circuits of the pipeline system.

Classification of balancing valves

When choosing a balancing valve, the design parameters of the pipeline system at the installation point should be taken into account:

• nominal and maximum pressure of the working medium,
• pressure difference in the supply and return circuit,
• nominal and maximum flow rate and flow rate of the working fluid,
• carrier temperature.

These parameters vary greatly depending on the application on:

• industrial facilities,
• sections of main pipelines,
• objects of housing and communal services,
• objects of individual construction.

By type of pipeline system, balancing valves are used for systems:

• cold water supply,
• hot water supply,
• heating,
• cooling,
• conditioning.

They also differ in the type of coolant in cooling and heating systems:

• water,
• glycol solution.

Balancing valves can be installed in the forward, reverse and bypass circuits of the pipeline system.

According to the type of setting values, they are divided into adjustable and fixed.

Types of balancing valves

The simplest type of instrumentation is manual balancing valves. With their help, you can set up individual sections of the pipeline and the entire system as a whole, measuring the pressure and flow of the working medium at control points. They allow you to disable individual parts of the system and release them from the working media. With their main advantage - a low price, they also have a number of disadvantages. The main one - the balance is set for the average design parameters of the constant flow of the working medium. With significant fluctuations in the flow, and this occurs in particular in the water supply systems of the housing and communal services, the balancing can be significantly disturbed.

This shortcoming is eliminated by automatic balancing valves, which are installed in pairs on the inlet and return circuits, partially acting as a bypass valve. When properly adjusted during initial installation, little or no further intervention is required, performing automatic adjustments.

Valves with temperature control of the working medium are used in heating, cooling, air conditioning, underfloor heating, etc. In addition to the pressure balance, they allow you to set the temperature balance in certain sections of the pipeline system.

Various combined systems for various types of working environment, for stabilization of its speed, flow, automatic redistribution at peak loads, etc.

Rules for installing a balancing valve

The installation of balancing valves is carried out in accordance with the general rules for the installation of pipeline systems. It is only necessary to pay attention to the direction of flow indicated on the body of the device, protection against ingress of foreign objects or dirt into the body. To exclude turbulences in the pipeline, it is necessary to provide for the presence of straight sections of the pipe before the valve - 5 diameters, after it - 2 pipe diameters. For automatic valves, it is also necessary to provide for the presence of a charging fitting in the circuit, through which the initial filling of the circuit must be carried out with the inlet valve closed.

Balancing Valve Manufacturers

The most famous manufacturer of hydro - and thermoautomatics and refrigeration equipment is the Danish company DANFOSS, which produces products worth 2 billion euros per year.

Also known in the market:

• Finnish company Vexve,
• Danish Broen,
• Italian GIACOMINI,
• Russian ADL.

I present to your attention a short video that describes the automatic balancing valve well:

Proper calculation, installation and adjustment of the pipeline system, regardless of its purpose, will save a lot of money and material resources during operation, as well as avoid unforeseen situations, accidents, etc. This is a job that only qualified specialists can do - hydraulic and heat engineers.