What is the difference between a hydraulic accumulator and an expansion tank? Expansion membrane tank for heating: design features and principle of operation Functions and types of expansion tanks

The next step is to install the tank into the system or open the shut-off valve, if it has been installed. Then the make-up valve is unscrewed and the pressure Pnach is set according to the following formula:

• Pstart > or = P0 + 0.3 bar.
• Having recorded and established the received data, you can start the water. In this case, it is important to read the pressure gauge relative to the pressure Exp. The last thing is to turn on the make-up again and bring the pressure to Pkon. Its size is calculated by the formula:
• Pcon< или = Pкл – 0,5 бар.
• In this case, Pkl is the pressure of the safety valve. For private households this figure is 3 bars.

Don't forget that in case of a complete breakdown you can...

Correct setting tank is the prerogative of specialists. Why are the above calculations needed? This data will help the user configure the tank independently in the following cases:

• pressure has dropped to critical levels or is absent altogether;
• the membrane needs to be replaced;
• setting up a tank for a non-standard object.

Operating principle of a membrane expansion tank

As a result of heating the water, the coolant expands, the membrane gradually stretches, displacing air from the chamber. Thus, there is an increase in pressure in the entire system as a whole. When the temperature drops, the water that is in the expansion tank is pushed back into the system. And this will happen exactly until the air and water pressure levels are balanced.

Very important element In heating there is an expansion tank; it helps remove excess pressure in the heating system when its temperature rises. Tanks for the heating system are of closed and open type. Open have whole line disadvantages, but membrane (closed) ones are more advanced and do not have the disadvantages that open containers have.

Reflex V 1000 membrane expansion tanks are designed to compensate for changes in water volume that may occur when the water heats up. When choosing an expansion tank for your heating system, you need to pay attention Special attention material and quality of the product with a durable and reliable body. One such reliable tank is the Reflex n 1000 model for closed heating systems.

Description of design and principle of operation

All tanks German company Reflex are made from sheet steel of the highest quality. A model such as Reflex N 1000 is expansionary pressure tank with non-replaceable membrane. It is intended for use in closed heating and cooling systems and for systems with solar collector. It was created to compensate for the volume of coolant during the period of heating or cooling of the liquid.

The container with a membrane is made of high quality materials and has polymer coating, this model is offered in red and gray color. The Reflex N 1000 membrane container is divided into two parts (chambers) membrane. One of them is low inert gas- nitrogen, it is specially pumped there under pressure, the second chamber contains water.

When the water begins to heat up, the excess volume of liquid enters the membrane tank, this process leads to gas compression, which is contained in another part of the unit. A slight pressure begins to build up in the entire container so that the pre-valve does not operate. When the water cools, it returns again under gas pressure.

Features and Specifications

Expansion membrane tanks found wide application. Most often they are installed in private homes, but they are also used in industrial complexes. The Reflex N 1000 tank model has the following technical characteristics:

1. Heating + cooling
2. The membrane is irreplaceable
3. Threaded connection
4. Modern attractive design
5. High-quality polymer coating.

Expansion tank from German manufacturer Reflex N 1000 has the following characteristics:

A membrane container has an important advantage - the tightness and mobility of the membrane creates in both chambers, where there is water and gas, the pressure is the same. This property protects the system as a whole from depressurization.

Assembly and care of the device

The expansion tank is connected through shut-off valves, this provides protection against unexpected disconnection of the tank from the heating system. It can also be connected to a multi-boiler system for each individual boiler or for the entire system.

The Reflex membrane expansion tank requires an annual preventive inspection. It is necessary to carry out measuring the initial pressure first in the air chamber, and then measure the pressure in the chamber with water. Before servicing the tank, it must be disconnected from the system; the water chamber must be empty; the water can be drained through a drain device.

Application of the Reflex membrane tank and its quality guarantee

Reflex is a universal diaphragm expansion vessel with diaphragm. The entire Reflex product line is different robust construction and reliability in operation, does not require additional energy costs during operation. Thanks to your distinctive properties and technical specifications successfully used in individual construction e, as well as in industrial and residential facilities.

The protective polymer coating serves reliable protection from damage with outside. The system is equipped with everything necessary to be convenient for specific operating conditions.

Conclusion

All expansion tanks of the German manufacturer Reflex have high quality, their coating is resistant to any environment and can withstand various temperature fluctuations. The entire design is designed to provide compensation for the coolant in the event that during operation the temperature in the Reflex N 1000 unit heats up or cools down.

Considering German quality, the entire system has proven to be very reliable, many citizens have already appreciated this unit, so numerous reviews about the Reflex N 1000 tank are only positive. The products of the German company are confirmed by all necessary certificates.

When heated, any coolant expands and increases in size. As a result, the pressure in a closed heating system gradually increases and reaches a critical point. The membrane expansion tank of the heating system is designed to prevent the destruction of components and pipelines due to expansion of the coolant.

The main function of the expansion tank is to optimize the operating pressure in the heating system. Closed heating systems cannot operate properly unless a membrane heating tank is connected to them.

Diaphragm expansion tank design

• Metal body - a prerequisite for the production of tanks is the ability to withstand extreme loads without breaking the seal.
• The membrane must be highly elastic and capable of responding to changing pressure associated with heating of the coolant. At the same time, high demands are placed on the membrane in terms of strength. Typically, rubber is used in the production of membranes.

The design of a membrane heating tank for closed heating systems involves the use of tanks with replaceable and non-replaceable diaphragms. Each design has both its advantages and disadvantages.

How does a membrane expansion tank work?

• Water or antifreeze begins to expand, resulting in an increase in its volume in the system.
• The design of a membrane-type expansion tank implies that it is filled with gas.
• The membrane is a kind of layer between the gas and the coolant.
• When heated, the liquid, expanding and creating pressure, enters the tank and displaces air or gas.
• After the coolant pressure drops, the gas pushes the coolant out of the tank using a membrane.
• The operation of the safety valve in a heating system with a membrane tank is to relieve excess gas pressure in the event of large expansion of the coolant. The pressure relief valve ensures safe operation of the system in case of overheating of the fluid or antifreeze.

For normal operation heating in the membrane tank there must be a pressure corresponding to the height of the top point. If the tank is installed in two-storey house And maximum height from the boiler on the ground floor to the radiator on the top 7 meters, then we take 0.7 into the calculations and add 0.5 to it. We obtain the initial pressure when coolant is supplied to the system. The resulting coefficient for the tank should be lower by 0.2. It turns out that the normal pressure in the membrane-type expansion tank in this case is 1 atm.

Like all heating equipment, the membrane tank needs maintenance. It needs to support appropriate operating pressure and refill with gas or air from time to time.

Types of expansion tanks for heating systems

• The expansion tank membrane is in the form of a diaphragm. This device is more like a barrel separated by a movable rubber partition. When the liquid enters its section, it fills the reservoir, and then, under pressure, it begins to compress the gas, gradually moving the membrane. This device is not always effective for houses with a small heated area.
• Round membrane tanks of balloon type. In this case, the air chamber is located around the perimeter of the entire tank. It surrounds the water chamber. As pressure increases, this chamber begins to expand like an inflated rubber ball. The uniqueness of such a device is that with its help it is possible to more accurately control the coolant pressure, even in closed systems with a small volume of liquid in the pipeline.
• Non-removable membrane. The diaphragm is attached around the entire perimeter. Non-removable membranes are intended for use in private heating systems and for heating cottages. Limited use and installation in small industrial facilities is allowed.
• Tank with replaceable membrane. They are a hollow pear. Removable membranes are able to work effectively in systems with high heating intensity of the coolant and high atmospheric pressure. The advantage of such a device is the ability to replace the diaphragm. The disadvantage is that high demands are placed on the work required to change the membrane. The membrane must not be distorted during installation.

The role of the expansion tank in the heating system is not limited to depreciation overpressure. Before choosing a suitable device, you need to determine for what purpose you plan to use it.

How to calculate the volume of a membrane type expansion tank

• Temperature range considered operating for the device.
• Membrane elasticity.
• Diffusion stability.
• Dynamic indicators.

V=(V sys ×K)÷D

The volume of the expansion tank for a closed heating system is, according to this formula, the product of the volume of the system V sys and the coefficient of increase in coolant K (it is 4%) divided by the efficiency of the tank itself.

D=(Pmax-P start)÷(Pmax+1)

P - in in this case is an abbreviation for maximum and initial pressure. Using these two formulas, you can easily perform calculations and select the required model.

In addition to the standard round device You can purchase a rectangular membrane-type expansion tank; it is more convenient to use and has an attractive appearance.

How to install a membrane type expansion tank

1. It is better to install the expansion tank before, rather than after, the circulation pump, this will help to avoid surges in pressure. There are no other restrictions regarding the installation location.
2. After installation, it is necessary to check whether the operating pressure of the device matches that required. The check can be done quite simply if you install a pressure sensor in the tank when connecting. A sensor measuring the pressure in the tank is installed directly at the inlet. If the existing indicators do not meet the required ones, it is necessary to bleed the air and pump the device again until the diaphragm pressure meets the required one.
3. When the heating system is closed, the expansion tank is correctly installed so that the inlet valve (water pipe) points downwards. This will allow the coolant to drain, even if the membrane fails. Some models have a coolant level indicator, which allows you to determine whether the liquid has been completely drained from the system.

Installation membrane tank is a prerequisite for installing a closed-type heating circuit. Some boilers are already equipped with such a device; in this case, if necessary, installation of an additional tank is allowed.

An autonomous heating system must have an expansion tank for heating, or a compensator. Its function is to compensate for the excess pressure that occurs in the system when the coolant expands due to heating. With a rapid increase in temperature, the coolant liquid expands and a pressure surge occurs, the so-called water hammer. It can destroy pipeline elements and connecting fittings. Other names for expansion devices: hydraulic accumulator, expansomat.

Design and principle of operation of expansion tanks for heating

Heating systems can be open or closed. Accordingly, heating expansion tanks exist in open and closed types.

Open type tanks

An open expansion tank for heating is a parallelepiped-shaped container made of stainless steel. This tank is placed at the highest point of an open heating system, usually in the attic.

Pipes connected to the tank:

• mainline;
• circulation;
• alarm, with locking device.

In this type of heating system, the coolant (water) circulates naturally, without pumps. Despite the comparative cheapness and simplicity of such heating, it is gradually becoming a thing of the past due to numerous shortcomings.

• In an open tank, the coolant constantly evaporates, so you need to monitor the water level and add it as necessary. For the same reason, it is problematic to use another coolant, such as antifreeze - it evaporates even faster.
• It is possible for water to overflow from the tank, so it is necessary to ensure its drainage into the sewer or drainage system.
• An open expansion tank requires good thermal insulation so that the water does not freeze in severe frosts.
• Installation in the attic will require additional pipes and connecting elements.
• Air entering the system from the expansion device provokes corrosion of the pipeline and radiators, and also leads to the appearance of air locks.

The open compensator system is suitable for heating small one-story houses. More large houses heated closed systems.

Closed tanks

A closed, or membrane expansion tank of a heating system contains an elastic membrane inside, which divides the internal volume of the compensator tank into two compartments, gas and liquid. The gas part contains air under pressure (in some models - nitrogen or inert gas), and the liquid part receives excess coolant when heated.

Closed tank (membrane)

The higher the temperature, the more the liquid part of the accumulator is filled. At the same time, the gas part contracts and the pressure in it increases. When the threshold value is reached, the safety valve is activated and excess pressure is released. And when the heating system cools down, the reverse process occurs and the coolant returns from the tank to the pipeline.

Operating principle of a membrane expansion tank

There are two types of membrane compensators.

1. With a diaphragm type membrane. These are small sized tanks. The diaphragm membrane in them is non-removable and cannot be replaced: if it breaks, you will have to completely replace the device.
2. With a balloon (pear-shaped) membrane. It can be changed when worn out; it is used in large thousand-liter tanks.

The volume of expansion tanks for heating can vary widely from two to several thousand liters. The shape of the closed hydraulic accumulator is flat or cylindrical. In a flat expansion tank, the membrane-diaphragm is located vertically, in a cylindrical tank it is horizontal.

It is worth paying attention: a membrane compensator is sometimes mistakenly called a vacuum expansion tank for heating. However, this device does not use a vacuum. The heating system may have a vacuum deaerator to remove air microbubbles from the water.

Installing a membrane expansion tank

Unlike an open one, a membrane accumulator can be installed directly into the heating point, next to the boiler. Usually it is placed on a straight section in front of circulation pump, it is desirable that water (or other coolant) enters the compensator from above. It must be equipped with a pressure gauge, a safety valve and connected to the return line.

Hydraulic accumulators with a volume of up to 30 liters are mounted on the wall, larger ones are installed on the floor. When mounting on a wall, the tank should be securely fastened, since its weight increases sharply when filled with water.

Several membrane tanks in a heating point

Important performance characteristics and compensator volume calculation

When selecting an expansion tank, take into account the maximum operating temperature and pressure. For example, the coolant can heat up to +120° C, and the peak pressure in the heating expansion tank can reach 6-10 bar (the usual average value is 2-4 bar). Therefore, the characteristics of the membrane, its durability, heat resistance, compliance sanitary standards.

The volume of the compensator depends on the volume of coolant as a whole in the system. It is not necessary to calculate the volume mathematically accurately; a simplified method is often used: select a tank with a capacity equal to 10% of the total volume of the coolant. And if this volume is unknown, then they proceed from the power of the boiler and the type of heating devices. The ratios are as follows: for heating radiators they take – 11 l/kW, for heated floors – 17.5 l/kW, for wall-floor heaters – 7.5 l/kW.

If the capacity of the selected compensator is insufficient, the safety valve will release pressure too often. In this case, it is enough to purchase and connect in parallel another expansion tank.

It is quite difficult to take into account all the nuances, especially since in each house the heating system necessarily has its own characteristics. In order not to make a mistake when choosing and installing a device, it is better to contact a specialized company.

Video: installation of an expansion tank

Today no one will be surprised by an autonomous water supply system. Such designs are very convenient and practical, but their operation often requires devices that a person using only centralized water supply, may simply not know. For example, an autonomous water supply system will long time operate uninterruptedly only if an expansion tank for water supply is included in it. Modern industry produces many of the most different models such devices. To choose for yourself best option, it is necessary to navigate the types of equipment and have a good understanding of the principle of its operation.

Design and functions of this equipment

Types of membrane tanks

There are two main types of expansion membrane equipment.

Device with replaceable membrane

home distinctive feature– possibility of replacing the membrane. It is removed through a special flange, which is held on by several bolts. It should be taken into account that in large-volume devices, in order to stabilize the membrane, it is additionally secured with its rear part to the nipple. Another feature of the device is that the water filling the tank remains inside the membrane and does not come into contact with the inside of the tank. This protects metal surfaces from corrosion, and the water itself from possible contamination and significantly extends the life of the equipment. Such models are produced in both horizontal and vertical versions.

Devices with a replaceable membrane differ more for a long time service, since the most vulnerable element of the system can be replaced and water does not come into contact with metal body device

Device with a stationary diaphragm

In such devices, the inside of the tank is divided into two parts by a rigidly fixed membrane. It cannot be replaced, therefore, if it fails, the equipment will have to be replaced. One part of the device contains air, the other contains water, which is in direct contact with the inner metal surface of the device, which can provoke rapid corrosion. To prevent metal destruction and water pollution inner surface The water part of the tank is coated with special paint. However, such protection is not always durable. Devices are available in horizontal and vertical types.

A type of device with a rigidly fixed membrane. The design assumes that water is in contact with the walls of the equipment

In our next material Expert recommendations on choosing a membrane tank are presented:

How to choose the right device?

The main characteristic on the basis of which equipment is selected is its volume. In this case, the following factors must be taken into account:

• Number of people using the water supply system.
• The number of water intake points, which include not only showers and taps, but also Appliances, for example, washing machine and dishwasher.
• The likelihood that water will be consumed by several consumers at the same time.
• Limit number of start-stop cycles in one hour for installed pumping equipment.

• If the number of consumers does not exceed three people, and installed pump has a capacity of up to 2 cubic meters. m per hour, a tank with a volume of 20 to 24 liters is selected.
• If the number of consumers is from four to eight people and the pump capacity is within 3.5 cubic meters. m per hour, a tank with a volume of 50 liters is installed.
• If the number of consumers is more than ten people and the productivity of the pumping equipment is 5 cubic meters. m per hour, choose an expansion tank of 100 liters.

When selecting the desired model device, it is worth considering that the smaller the volume of the tank, the more often the pump will turn on. And also the fact that the smaller the volume, the greater the likelihood of pressure surges in the system. In addition, the equipment is also a reservoir for storing a certain supply of water. Based on this, the volume of the expansion tank is adjusted. You should know that the design of the device allows the installation of an additional tank. Moreover, this can be done during the operation of the main equipment without labor-intensive dismantling works. After installing the new device, the volume of the tank will be determined by the total volume of the containers installed in the system.

Except technical characteristics When choosing an expansion tank, special attention should be paid to its manufacturer. The pursuit of cheapness can result in much more significant expenses. Most often, to produce models that are attractive for their cost, the cheapest materials are used, and, as practice shows, they are not always of high quality. The quality of the rubber from which the membrane is made is especially important. Not only the service life of the tank, but also the safety of the water that comes from it directly depends on this.

When purchasing a tank with a replaceable membrane, be sure to check the cost of the consumable element. Very often, in the pursuit of profit, not always conscientious manufacturers significantly increase the price of a replacement membrane. In this case, it will be more appropriate to choose a model from another company. Most often, a large manufacturer is ready to be responsible for the quality of its products because it values ​​its reputation. Thus, it is worth considering models from these brands first. These are Gilex and Elbi (Russia) and Reflex, Zilmet, Aquasystem (Germany).

The volume of the expansion tank for water supply may vary; it is selected based on the needs of the users. If a larger volume is subsequently required, an additional device can be installed

Features of self-installation

All expansion tanks can be divided into two groups, determined by the connection method. There are vertical and horizontal models. There are no special differences between them. When choosing, they are guided by the parameters of the room where the equipment will be located. During the installation process, you should adhere to the following recommendations:

• The expansion tank is installed in such a way that it can be easily accessed for maintenance.
• It is necessary to provide for the possible subsequent dismantling of the connecting pipeline to replace or repair the equipment.
• The diameter of the connected water supply cannot be less than the diameter of the pipe.
• The device must be grounded to avoid electrolytic corrosion.

The device is installed on the suction side of the pump. On the segment between pumping equipment and the connection point, it is necessary to exclude all elements that can introduce significant hydraulic resistance into the system. We connect the make-up line to the circulation circuit of the entire system.

According to the type of installation, expansion tanks of horizontal and vertical connection are distinguished

Please also pay attention to the material about what malfunctions most often occur in pumping stations, and how to fix them yourself:

The expansion tank is an integral part autonomous system water supply It supports, prevents premature damage to the pump and retains a certain supply of water. However, all these functions are performed only if the structure is correctly selected and installed correctly. Therefore, if you lack experience, it is better not to get carried away with amateur activities, but to find qualified specialists who will install any device with high quality.