Expansion membrane tank– a mandatory component, without which the functioning of the system is not possible. It is he who creates the necessary pressure for the full operation of the water supply system, makes reserve water reserves and even performs a number of protective functions. In connection with such a high importance of equipment, the question naturally arises: how to choose and correctly install a tank? To understand, let's approach the issue comprehensively: we bring to your attention the structure and operating principles of the expansion device, its types, selection features, as well as the connection diagram and useful instructions on setup with video.
Functions and operating principle
A membrane tank is a sealed, predominantly metal tank, consisting of two separated chambers: air and water. The separator is a special rubber membrane - it is usually made of strong butyl, which is resistant to the development of bacterial microorganisms. The water chamber is equipped with a pipe through which water is directly supplied.
The main task of the expansion membrane tank is to accumulate a certain volume of water and supply it at the user’s request under the required pressure. But the functions of the device are not limited to this - it also:
- protects the pump from premature deformation: thanks to the water reserve, the pump does not turn on every time the tap is opened, but only when the tank is empty;
- protects against changes in water pressure when using several taps in parallel;
- protects against water hammer that could potentially occur when the pumping unit is turned on.
Operation of the device
The principle of operation of the tank is as follows. When the pump turns on, water begins to be pumped into the water chamber under pressure, and the volume of the air chamber at this time decreases. When the pressure reaches the maximum allowable level, the pump turns off and the water supply stops. Then, as water is drawn from the tank, the pressure decreases and, when it decreases to the minimum allowable level, the pump turns on again and resumes pumping water.
Advice. During operation of the tank, air can accumulate in the water chamber, which causes a decrease in the efficiency of the equipment, so at least once every 3 months it is necessary to carry out maintenance of the compartment - to bleed excess air from it.
Types of membrane tanks
There are two types of expansion membrane tanks:
Advice. When choosing between a replaceable and permanent membrane, consider one important factor: in the first case, the water is completely contained in the membrane and does not come into contact with the inner surface of the tank, which eliminates corrosion processes, and in the second case, the contact is maintained, so it is impossible to achieve maximum protection against corrosion.
Features of choosing a tank
The main factor in choosing a membrane tank is its volume. When calculating the optimal tank volume, the following nuances should be taken into account:
- number of users of the water supply system;
- number of water intake points: taps, shower and jacuzzi outlets, outlets for household appliances and boilers that work with water;
- pump performance;
- the maximum number of pump on/off cycles in one hour.
To calculate the approximate volume of the tank, you can use the following guidelines from experts: if the number of users is no more than three, and the pump capacity is no more than 2 cubic meters per hour, then a tank with a volume of 20-24 liters is quite sufficient; if the number of users is from four to eight, and the pump performance ranges from 3-3.5 cubic meters per hour, a tank with a volume of 50-55 liters will be required.
When choosing a tank, remember: the more modest its volume, the more often you will have to turn on the pump and the higher the risk of pressure drops in the water supply system.
Advice. If you assume that over time there will be a need to increase the volume of the membrane tank, buy equipment with the ability to connect additional containers.
Tank connection diagram
The membrane tank can be installed either vertically or horizontally, but in both cases the connection diagram will be identical:
- Determine the installation location. The device must be located on the suction side circulation pump and before the branching of the water supply. Make sure that there is free access to the tank for maintenance work.
- Secure the tank to the wall or floor using rubber pads and ground it.
- Connect a five-pin fitting to the tank nozzle using an American fitting.
- Connect in series to the four free terminals: a pressure switch, a pipe from the pump, a pressure gauge and a distribution pipe that supplies water directly to the intake points.
Tank connection
It is important that the cross-section of the connected water pipe is equal to or slightly larger in relation to the cross-section of the inlet pipe, but in no case should it be smaller. One more nuance: it is advisable not to place any technical devices, so as not to provoke an increase in hydraulic resistance in the water supply system.
Equipment setup instructions
After the membrane tank is installed and connected, it is important to properly configure and start it up. Let us dwell on the main points of this stage.
The first step is to find out the internal pressure of the tank. In theory, it should be 1.5 atm, but it is possible that a leak occurred during storage of the device in a warehouse or during transportation, which caused a decrease in such an important indicator. To make sure the pressure is correct, remove the spool cap and take measurements with a pressure gauge. The latter can be of three types: plastic - cheap, but not always accurate; mechanical automobile - more reliable and relatively affordable; electronic – expensive, but as accurate as possible.
After measurements, you need to decide which pressure will be most optimal in your case. Practice shows that for the normal functioning of plumbing and household appliances, the pressure in the membrane tank must vary within 1.4-2.8 atm. Assuming you've chosen these metrics, what next? First, if the initial pressure in the tank is below 1.4-1.5 atm, it must be increased by pumping air into the corresponding chamber of the tank. Then you should set the pressure switch: open its cover and use the large nut P to set the maximum pressure value, and use the small nut ∆P to set the minimum value.
The process of setting up equipment is simple
Now you can start the system: as water is pumped in, watch the pressure gauge - the pressure should gradually rise, and after it reaches the maximum set point, the pump should turn off.
As you can see, without an expansion membrane tank you really can’t even count on the full operation of your individual water supply. Therefore, if you want to uninterruptedly enjoy the benefits of civilization, carefully approach the selection and connection of the device - all the principles and subtleties are before you, so we advise you to study them well and only then proceed to active actions.
Calculation of accumulator volume: video
Membrane expansion tank for water supply: photo
The heating system of a private home (as well as water supply) must be functional and reliable. If during installation any violations were made or something was not done, then it will not last long, even if it works for some time. One of the main elements in any autonomous system associated with the use of water is an expansion tank for water supply, the selection, installation, installation of which will be discussed in this material.
What is this?
Even the name itself speaks for itself - an expansion tank is needed to expand the entire heating circuit of a house or water supply pipes through which hot or cold water flows. The fact is that during heating, the liquid increases in volume, and the pipes through which it flows do not change their physical parameters - their elasticity tends to absolute zero. This means that the pressure inside the pipes and the entire installation will increase, which can lead to damage - so-called water hammers occur, and as a result, destruction individual elements installations or pipe circuits. This applies mainly to the heating system, but it also fully applies to hot water supply.
To avoid water hammer, engineers came up with the idea of including in the system a small reservoir filled with air, that is, a substance that, unlike water, is compressed. And if the pressure in the pipes increases during heating of water, then thanks to this tank it will increase quite slightly. "P , You can read in our article.”
On a note! Expansion tank It is often installed in other systems, but the purpose of its use is the same - to reduce pressure in pipelines and the risk of air locks.
This tank is also sometimes used to create a reserve stock. cold water and ensures the supply of liquid to any location in the system in a matter of minutes. At the same time, the average capacity of the container is about 30 liters.
For systems that provide water to a home, tanks equipped with membranes are most often used. This is a relatively small container, inside of which there is a diaphragm made of elastic material and dividing the device into two parts - with air and airless, or rather, water. When the water supply system is operating, the water chamber is filled with liquid and, acting on the membrane, compresses it, reducing the volume of the air part, increasing the pressure in it. As soon as the pressure reaches a certain level, the pump pumping water will stop. And it turns on when the pressure drops to minimum values.
On a note! The pressure inside the system can be monitored by a pressure gauge installed in it.
Such a tank allows you to ensure uninterrupted operation of the water supply system and stable water flow in any house, even a multi-story one.
Types of tanks
There are two types of expansion tanks - closed and open. They differ from each other in their design features.
Table. Types of expansion tanks.
| Type | Description |
|---|---|
| This is a tank that has a membrane separation between the compartments - water and air. The diaphragm in it is heat-resistant and avoids corrosion. Such a tank is sealed and looks like a small cylinder or ball made of metal. This element of the system serves for a long time, and if the membrane is damaged, it can be easily replaced with a new one. Also, additionally, for an expansion tank of this type, a pressure gauge and safety valve– all together they form a security system. |
| Such a tank is a container with a threaded connector at the bottom, which allows you to combine the device with the system. This structure must be installed in the highest part of the heating system. It is used extremely rarely, as it has a lot of disadvantages - this includes an increased risk of corrosion in pipes, fairly decent dimensions, and rapid failure at critical pressure levels. The liquid level in such a container directly depends on how much water is in the heating circuit. |
Membrane tanks, in turn, are divided into two types - with a replaceable diaphragm and with a stationary one. The replaceable membrane speaks for itself - if necessary, it can be easily changed by removing it through a flange secured with several bolts. An expansion tank of this type lasts as long as possible, and the shape of the body can be either vertical or horizontal, which makes it possible to select a container for a specific room.
Attention! In large expansion tanks, the membrane is additionally secured with a nipple.
In containers with a stationary membrane, this part cannot be replaced - it is tightly attached to the walls of the body. If the unit fails, it is completely replaced. By the way, the water in such an installation, unlike the previous type, comes into contact with the metal of the tank, as a result of which a corrosion process occurs on its inner surface. Installation can also be either vertically or horizontally oriented.
Expansion tanks are not only mounted, but also floor-mounted. They can also have a flat shape and differ in color: blue ones are for cold water, red ones are for hot water.
Popular models
Nowadays the market offers a huge range of different expansion tanks from various manufacturers. The models differ from each other in quality, size, shape and even color, although they are similar in principle to each other. Selecting a tank for a specific water supply system will not be difficult. You should pay attention to tank models from following companies– Russian “Gileks” and Italian Elbi, Aquasystem, as well as Refix (Reflex), Zilmet. , You can read in our article.
The advantages of Gilex tanks are the complete absence of the risk of air locks in the system and the absence of contact of water with air, which prevents evaporation of liquid, and rust does not damage the pipes. The brand produces tanks of various sizes - from 6 to 700 liters. The disadvantage of the containers is that only units with a volume of over 24 liters have removable membranes. By the way, the diaphragm is made of high-quality EPDM - ethylene-propylene-diene rubber. Gilex tanks are economical, durable, inexpensive, but at the same time reliable and can have different shape.
Elbi tanks have everything Required documents, including a certificate of conformity and a sanitary-epidemiological conclusion, allowing them to be safely used in residential buildings. There are vertical, horizontal, and also for sanitary water. Vertical tanks belong to the AS/AC series and have replaceable diaphragms, can be of different volumes - from 5 to 25 liters - and are used in home water supply systems, as well as in irrigation systems and other installations that do not require powerful water pressure. The membranes inside the containers are made of EPDM, working temperature ranges from -10 to +99 degrees. The tank is protected from corrosion by durable paint.
Elbi tanks for horizontal installation belong to the AFH series and have replaceable membranes. Their capacity is greater than that of the previous series - from 25 to 100 liters of water. Such installations can already be used in small industries. The tanks are made of durable steel and have a special platform for mounting the pump.
Refix tanks are suitable for use in both technical and drinking water supply systems and are excellent hydraulic accumulators. All parts in contact with water are protected from rust, and the liquid is perfectly stored inside the rubber bulbs. Models DD, DE are designed for water-saving purposes, used in drinking water supply systems, ideal for use in conditions with a high level of rust formation. DE series tanks have a bulb, which is replaceable only in models with a volume of over 50 liters. Models of the HW series, designed for individual water supply systems, also have legs for installation on the floor and a place for mounting the pump.
The international company Zilmet has held a high position in the equipment market for more than 50 years, and in Europe it is considered the largest manufacturer of expansion tanks. Their Hydro-PRO devices are used to work with any water in various types installations. The equipment is made of durable and high-quality carbon steel, and special internal MIG welding is used in production, which avoids damage to butyl rubber membranes. The inside of the tanks is coated with high-strength powder resin, which prevents rust from prolonged contact with moisture. Operating temperature range – from -10 to +99 degrees.
Aquasystem tanks have replaceable membranes and come in various volumes - from 8 to 50 liters. The maximum coolant pressure is 0.5 MPa, and the air pressure is 0.15 MPa. The operating temperature range of the equipment varies from -10 degrees to +110. The tanks are made of black steel, powder coated.
Attention! Don't chase the cheap! As you know, the miser pays twice. The point is that the use is not quality equipment can lead to serious damage not only to the expansion tank, but also to the system itself, and repairs will cost much more than buying high-quality equipment right away.
Regarding the quality of the equipment it is worth Special attention pay attention to the rubber from which the diaphragm is made. Good rubber is not only the key to long service life of the equipment, but also the safety of those who will use water from a water supply system equipped with a tank.
Selecting a hydraulic accumulator
When choosing an expansion tank, you should pay attention to its characteristics and the materials from which it is made. The material from which the bulb or diaphragm is made, its strength and quality, compliance with all hygienic and sanitary standards, permissible temperatures use. From the right choice The service life will depend on the operating conditions.
Important point when choosing equipment - correct selection required volume of container. This will prevent the number of pump starts in the system, which will extend its life. You can calculate the correct volume for a cold water supply system using the formula:
Vt = 16.5*(Qmax/a)*((Pmax*Pmin)/((Pmax – Pmin)*Pprec)),
- Qmax is the maximum water consumption (l/min);
- a – the optimal frequency of equipment switching on in 1 hour (varies from 10 to 15 and is indicated in the pump passport);
- Pmax and Pmin – values (measured in bars) that show the pump on and off pressure (pressure switch settings);
- Pprec (bar) is an indicator of the initial pressure in the cavity with air inside the expansion tank (should not be greater than Pmin; on the contrary, it is set 0.5 less than Pmin).
Note! When calculating using this formula, 1 is added to all values. And the value of the container volume Vt obtained by the formula is always rounded up.
For hot water supply systems, the volume is calculated differently:
V = 0.0221*C / (1-((Pi+1)/(Pf+1)),
- C – total amount of water in the water heating system;
- 0.0221 – thermal expansion indicator, in the range of 10-60 degrees equal to this figure;
- Pi – indicator of pre-injection pressure of the expansion tank;
- Pf – pressure indicator during release of the safety valve.
The volume of water used, in turn, is affected by the number of people living in the house, the number of points of water use (taps, washing machines etc.), the ability to include several such points at once.
Attention! If you use a tank of the wrong size (with underestimated performance), then soon it will begin to leak due to heavy load. Fortunately, as the number of people living in the house increases, and therefore the load on the equipment, you can install an additional tank without removing the already installed one.
Expansion tanks for water supply systems
For water supply systems, underfloor heating
not flow-through, without shut-off and drain valves
membrane conforms to DIN 4807 T3
in tanks with a volume of 60 liters or more - the membrane is replaceable
an anti-corrosion coating is applied to the surface in contact with water
equipped with a pressure gauge for diameters of 1000 or more
blue color
preliminary pressure 4 bar
The main function of expansion tanks is to maintain constant pressure in water supply systems. The price of this equipment at the Moscow Thermal Company is available to a wide range of consumers.
Structurally, an expansion tank for water supply is a container of a certain volume, inside of which there is a membrane made of bottle. The neck of the membrane, like the membrane itself, is sealed and connected to the lid of the vessel with a removable pipe. All expansion tanks for Reflex water supply systems are equipped with a membrane that can be replaced in the event of equipment failure.
The main advantages of an expansion tank for water supply
Expansion tank for water supply is very popular in closed systems due to its unique technical and operational characteristics:
- the polymer coating perfectly protects the tank from corrosive processes;
- a replaceable membrane makes it possible to significantly extend the service life of the equipment;
- ergonomic design will optimally fit into the interior of the room.
At the same time, the water membrane chamber is made of wear-resistant rubber material.
If you decide to buy an expansion tank for water supply, first of all, pay attention to such a parameter as the capacity of the vessel. Depending on the volume of the container, the expansion tank can be used not only as an additional water container, but also as the main one.
By purchasing an expansion tank for hot water supply from our company, you are guaranteed to purchase high-quality, reliable and proven equipment specifically designed for water supply systems. All products are certified and meet the highest international standards and requirements.
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 who uses only a centralized water supply may simply not know about. 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 internal part tank. What protects metal surfaces from corrosion, and 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 the metal body of the 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 internal metal surface 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 household appliances, for example, a 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 device model, it is worth considering that the smaller the tank volume, 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 work. 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 particular 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. In the section between the 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.
