Autonomous water supply system for modern home- this is not new. Quality Devices for water supply tested by users and time.

But it is better for buyers to familiarize themselves with the functionality of all devices. autonomous system water supply before purchase and installation.

Kinds

In order to properly pump water long time, a diaphragm expansion vessel is required.

For the convenience of the system and saving space, three types of these devices are on sale:

• floor;
• hinged;
• flat.

Specialist's note: when choosing between types of expansion tanks, remember that only the floor tank has a replaceable membrane.

What exactly adds an expansion tank to the system:

Operating principle

Fluid pressure builds up in the system. Then storage tank filled with a certain volume.

In it, the water compartment gradually increases, and the opposite compartment containing air decreases.

This process continues until equilibrium is reached, in other words, desired pressure in system. When the pressure drops below the level of air pressure, timely contraction of the inner membrane occurs.

Due to it, the water supply is normalized. The tank device functions as long as necessary to stabilize the pressure of water and air.

The right choice of instrument

Choosing a model with necessary functions and volume, consider the fact that the frequency of operation of the pump depends on the total volume of the tank.

The leading characteristic for any tank is not the functionality, but its volume.

At the same time, for each water supply system there are criteria that cannot be neglected, namely:

1. Number of permanent water users. (Daily use).
2. Number of points for water intake. (Appliances, faucets and other plumbing fixtures).
3. Approximate frequency of use of water intake points at the same time.
4. On-off cycle. You need to know exactly the one-hour limit of this cycle for your pump.

Approximate calculation:

When calculating for three permanent consumers, a tank with a total volume of 20-24 liters is installed. However, pumping equipment should produce approximately 2 cubic meters per hour.

When counting on four regular users with a margin, it is better to install equipment from 50 liters. The pump capacity in this case is approximately 3.5-3.7 cubic meters per hour.

If there are more than 10 consumers, then a tank of at least 100 liters is required, and pumping equipment with a rate of more than 5 cubic meters per hour.

To avoid breakage and expensive repairs, you need to carefully read the manufacturer.

In this choice, chasing a cheaper and dubious brand is not necessary. Incorrect savings can lead to breakdowns in the future.

Models with a low retail price inside are made, as a rule, without defects. But consumables are always made from the cheapest materials.

It is better to ask about the material from which the membrane is made. Its environmental friendliness and stability will improve comfort as well as the life of the system.

You may also be interested in the article about.

Read the article on malfunctions and repair of the hydraulic accumulator with your own hands.

How is it different from a hydraulic accumulator

Installation diagram of a membrane expansion tank Accumulator, membrane tanks and are devices that are most in demand in modern device plumbing and heating.

But it is better to know their significant differences, because the expansion tank creates the effect of pressure smoothing when the liquid is heated.

talking plain language, if there is no necessary space for water, which gradually changes its volume, then any non-plastic container will burst. For this, a device with a membrane was created, which normalizes the difference in a working system.

Both devices are appearance very similar. But their device, purpose and performance characteristics various.

The hydraulic accumulator is used to supply water for drinking.

Its main property is the supply of the desired water pressure.

The most important part in the tank and accumulator is the membrane.

The material from which it is made is different in devices for supplying water, including between the tank and the accumulator.

The arrangement of the chambers for air and liquid is also different. The accumulator inside is equipped with a “pear” tank. Air exerts pressure on it, it is between the walls of the tank and the water tank.

For each of the above devices, the most important parameter is the durability and reliability of the membrane. Its quality guarantees the stability of the entire system.

Watch the video in which the specialist explains how to choose a membrane expansion tank for home water supply:

Today we have to find out why we need to install an expansion tank in the water supply system, how the membrane tank works, and how to connect it correctly. We will start, however, by clarifying the wording and names of sanitary fittings.

Down with the confusion

In plumbing stores, you can find two varieties of these devices that differ from each other in color:

Image	Description
	1. Expansion tanks installed for heating - water supply are usually red and, in full accordance with the name, are designed to compensate for the thermal expansion of water or liquid heat carrier when heated. Liquids practically do not compress, and when they expand, the pressure in a closed circuit begins to grow at a catastrophic rate; air bag hinders its growth.
Hydraulic accumulators, or expansion tanks for drinking water systems - blue	2. Hydraulic accumulators - of blue color(cm. ) . They allow you to create an autonomous stock cold water, and act as a damper. That is, they extinguish pressure surges when opening / closing valves and turning on / off the pump supplying water.

The video in this article will help you learn more about membrane tanks.

Device

How are expansion tanks for water supply arranged?

A membrane tank is a steel container with a pipe for connecting to a water supply or heating system and a valve for pumping. It is divided by an elastic membrane into two compartments - air and water. The air compartment is often filled with nitrogen instead of air, which prevents corrosion of the tank walls.

Curiously: the expansion tank of a hot water or heating system is usually equipped with a membrane with increased heat resistance. There are no other design differences between it and the accumulator, so the expansion tank can be safely used as a hydraulic accumulator.

Scheme

Now let's take a closer look at why an expansion tank is needed in the water supply system, using specific schemes as an example.

Boiler piping

The boiler piping usually includes two fittings installed on its inlet pipe:

Image	Description
	Check valve. It lets cold water from the tap in storage water heater, but does not allow it to pour back when the cold water is turned off.
	Safety valve. Because the check valve turns the water supply and boiler into a closed circuit, when the water is heated, the pressure in it begins to rise rapidly. When it reaches dangerous values, the safety valve discharges excess water through the drain tube.

Useful: Check and safety valves combined in one housing are often sold under the name "boiler safety group".

While the volume of the boiler is small, the loss of heated water is insignificant or absent (thermal expansion is compensated by the elasticity of the walls of the water pipe). But with its significant volume hot water is discharged into the drainage in liters and tens of liters, which significantly affects the costs for the needs of hot water supply.

Connecting the expansion tank to the water supply system completely eliminates the loss of heated water. Its excess is accommodated by a membrane tank, which is accompanied by a slight increase in pressure in the circuit.

How big should an expansion tank be for a water supply system with a known volume boiler?

Usually it is taken equal to 10% of the volume of the boiler. Yes, the thermal expansion of water within reasonable temperature limits is less than 10%; however, do not forget that the capacity of the water compartment is not equal to the full volume of the membrane tank: part of this volume is occupied by air.

Therefore, in practice, rounding up is used: an expansion tank for water supply of 50 liters is able to provide safe work 500 liter boiler.

Water supply

How to use a hydraulic accumulator or expansion tank for cold water supply, providing yourself with water during its periodic shutdowns?

Do-it-yourself installation instructions for the device are extremely simple and consist of only two points:

1. Connect the tank pipe to any part of the water supply with a flexible or rigid connection;

1. Install a non-return valve at the cold water inlet. It will not allow water to drain from the tank into the disconnected and dumped main water supply.

Please note: the useful capacity of the membrane tank differs markedly from its full volume. For example, an expansion tank of a water supply system of 500 liters is able to store no more than 250 liters of water in case of a shutdown.

Well water

How to install an expansion tank in a water supply system with water supply from a well or well? Again, it is mounted at any point of the water supply.

In addition to the membrane tank, such a system includes:

Image	Description
	Submersible or It raises water and creates an excess pressure that ensures the operation of plumbing fixtures.
	Check valve. It is placed after submersible pump or at the suction pipe of a surface pumping station.
	An automatic relay that controls the operation of the pump (that is, turns it on when the pressure in the circuit drops and turns it off when the pressure reaches the upper critical value.

What pressure should be maintained in the expansion tank of the water supply system?

The answer cannot be given without knowing the settings of the automatic control of the pump. The pressure in the expansion tank of the water supply should be slightly lower (by about 0.2 atmospheres) than the pressure for turning on the pumping of water from the well. In this case, the pump will start before the remaining water from the membrane tank flows out through the open tap.

How to pump up an expansion tank in the water supply system if the pressure in it has fallen below the required level? This can be done with any air pump - bicycle, car, etc. The pump hose is connected to the spool on the diaphragm tank.

Water from a container

Water supply from storage capacity practiced in horticultural partnerships with scheduled water supply, and also where worn-out water mains are often turned off for repairs. The easiest way to supply water to the water supply is by gravity, from a tank installed in the attic.

However, this scheme has three serious drawbacks:

1. The water supply is limited by the strength of the overlap;
2. The attic must be insulated and heated, otherwise the water will freeze in the very first frost;
3. The pressure in a gravity water pipeline is limited by the vertical distance between the tank and the faucet. Meanwhile for normal operation household appliances (instantaneous water heaters, washing and dishwashers) you need a pressure of at least 3 meters (0.3 kgf / cm2).

The supply of water from a tank installed in the basement, underground or basement floor, using a pumping station, is devoid of all these disadvantages: the weight of the soil standing on the surface or the screed of the tank is not limited in any way, the pressure is created by the pump, and the temperature of the soil is below the freezing level all year round above zero.

What role does the expansion tank for water supply systems play in this scheme? The same as when supplying water from a well: it smooths out pressure surges and allows the pump to stand idle with little water flow.

What should be the connection diagram for the expansion tank for water supply? Again, the same as with autonomous water supply from a well or well.

However: in practice, a surface pumping station is usually placed to supply water from a tank, which is a pump, an automatic switch with a pressure sensor and a hydraulic accumulator on one frame.

The fight against water hammer

A water hammer is a short-term pressure surge that occurs in a closed circuit due to the inertia of a moving water flow when it stops instantly. Water hammer often takes pressure beyond the strength of pipes and flexible hoses; the consequences are very predictable - the owner gets breaks in the water supply at the seams and fittings.

If expansion tanks are connected to the water supply, the water supply is made absolutely safe: the air tank in this case also plays the role of a damper. A small volume tank is mounted on the water supply inlet or (with collector water distribution) on the collector.

Conclusion

We hope that our material will help the dear reader in the design and installation of their own water supply. Good luck!

An autonomous water supply system today no longer surprises anyone. Such designs are very convenient and practical, however, their operation often requires devices that a person using only centralized water supply may simply not know about. For example, an autonomous water supply system will work uninterruptedly for a long time only if it includes an expansion tank for water supply. Modern industry produces many of the most different models such devices. To choose the best option for yourself, you need to navigate the types of equipment and have a good idea of ​​​​the principle of its operation.

The device and functions of this equipment

Types of membrane tanks

There are two main types of expansion membrane equipment.

Membrane instrument

home distinguishing feature- the possibility of replacing the membrane. It is removed through a special flange, which is held on by several bolts. At the same time, it should be taken into account that in large-volume devices, in order to stabilize the membrane, it is additionally fixed with the back 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. What protects metal surfaces from corrosion, and the water itself from possible pollution and significantly extends the life of the equipment. Models are available in both horizontal and vertical versions.

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

Stationary Diaphragm Device

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 changed. 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 its rapid corrosion. To prevent metal destruction and water pollution inner surface the water part of the tank is covered with a special paint. However, this protection is not always durable. Devices of horizontal and vertical types are issued.

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

Our next article provides expert advice on choosing a membrane tank:

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 points, which include not only showers and taps, but also household appliances, such as washing machines and dishwashers.
• The probability that water will be consumed by several consumers at the same time.
• Limit number of start-stop cycles per hour for the set pumping equipment.

• If the number of consumers does not exceed three people, and installed pump has a capacity of up to 2 cu. 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 performance of pumping equipment is 5 cubic meters. m per hour, choose an expansion tank of 100 liters.

When selecting desired model devices, it should be borne in mind that the smaller the volume of the tank, the more often the pump will turn on. As well as 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 also adjusted. You should be aware 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. After installation of a new device, the volume of the tank will be determined by the total volume of the tanks installed in the system.

In addition to technical characteristics, choosing an expansion tank, Special attention you should contact its manufacturer. The pursuit of cheapness can result in much more significant costs. Most often, the cheapest materials are used for the production of models that attract with their cost, 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 directly depends on this, but also the safety of the water that comes from it.

When buying a tank with a replaceable membrane, be sure to clarify the cost of the consumable item. Very often, in the pursuit of profit, not always conscientious manufacturers significantly overestimate the price of a replacement membrane. In this case, it would 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, since it values ​​its reputation. Thus, it is worth considering the models of just such brands in the first place. These are Dzhileks and Elbi (Russia) and Reflex, Zilmet, Aquasystem (Germany).

The volume of the expansion tank for water supply can be different, it is selected based on the needs of 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. Distinguish between 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 placed. During the installation process, the following recommendations should be followed:

• Expansion tank installed in such a way that it can provide unhindered access for service.
• It is necessary to provide for the possible subsequent dismantling of the connecting pipeline for the replacement or repair of equipment.
• The diameter of the connected water supply can not be less than the diameter of the branch pipe.
• It is necessary to ground the device, so electrolytic corrosion can be avoided.

The device is mounted on the suction side of the pump. In the segment between the pumping equipment and the connection point, all elements that are capable of introducing significant hydraulic resistance into the system must be excluded. 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

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

An expansion tank is an integral part of an autonomous water supply system. It supports, prevents premature damage to the pump and retains a certain supply of water. However, all these functions are performed only under the condition of competent selection and proper installation of the structure. Therefore, in the absence of experience, it is better not to get involved in amateur performances, but to find qualified specialists who will install any device with high quality.

The expansion tank for cold water (hydraulic accumulator) is designed for installation in a water supply system, where it performs three main functional tasks:

1. Accumulating water and maintaining its constant pressure so that water from the tap flows evenly. All submersible water pumps for wells and most surface centrifugal ones have a connection limit per hour, so this feature of the accumulator allows the pump to turn on as the pressure decreases to a certain level.

2. Protection of the water supply system from possible water hammer that occurs when the water pump is turned on.

3. Accumulation of a reserve amount of water in the tank, so that in the event of a shutdown of the water supply system, it can be used.

The membrane type water expansion tank is a new generation equipment that has more advanced specifications and high levels of reliability and durability.

The design and principle of operation of the expansion tank of the membrane type

The accumulator consists of:

Metal tank;

rubber membrane pear-shaped from material that meets sanitary and hygienic standards

Adjusting nipple

The pump supplies water to the water supply system under pressure, then to the cavity of the accumulator. The membrane expands, while the air in the gas chamber is compressed. The tank is filled with water until the water-air pressure equalizes. The pump is switched off. When water is consumed, the pressure in the system drops and, by means of a relay, the water supply pump is turned on.

How to choose the right expansion tank for cold water

When choosing equipment, the main indicator is its volume. But it is necessary to take into account:

Number of users of the water supply system;

Number of water intake points (including household appliances);

The likelihood that water will be used in several places at the same time;

The number of on-off cycles of pumping equipment per hour.

Installing a membrane-type expansion tank in the system autonomous water supply allows you to significantly extend the uninterrupted service life of all technical elements of the system without the need to replace functional parts and current repairs.

In the online store of elite sanitary equipment "SanComf" you can purchase expansion tanks for heating and cold water supply from the leading manufacturer of tanks for heating and water supply - Reflex. Products are different high quality materials used, reliability and durability of operation.

expansion tank, being integral part hot water systems, designed to receive excess water resulting from the expansion of the liquid due to heating.

Refers to an auxiliary type of equipment. It helps to stabilize the pressure in the system and its safety.

This equipment, especially when purchased from authorized dealers, removes a number of problems from the residents of a private house, makes life more comfortable and enjoyable.

Functions and types of expansion tanks

The equipment technically performs two functions:

• liquid expansion compensation in the system to reduce the pressure in the system;
• compensation of water hammer due to excessive pressure.

Two types of expansion tanks are used for the hot water supply system.

open type

Equipment open type, which is connected using a threaded connector and is located at the highest point of the system.

Open type tanks are almost never used due to a large number flaws that significantly affect the safety of the hot water supply system and its operation:

• not tightness and the resulting corrosion;
• excessively large dimensions;
• inability to work in conditions high pressure systems;
• The water level in the tank depends on its volume in the system.

closed type

Second type auxiliary equipment- closed or membrane expansion tank. Today it is the most common.

Expansion tank installation

According to the connection method, all tanks are conditionally divided into two groups - vertical and horizontal. When choosing, you should focus on the parameters of the room. Technically correct installation requires strict adherence to the following recommendations:

• installation is recommended in a place that provides easy access for subsequent maintenance;
• provide for the possibility of dismantling the connecting pipeline in order to replace / repair equipment;
• the diameter of the water supply must be equal to the diameter of the pipe;
• to avoid electrolytic corrosion, the device is grounded.

In general, the connection diagram will require:

• shut-off shut-off valve - used to drain the tank, as well as check the pressure level;
• drain valve - with its help water pours out of the tank;
• pressure gauge - allows you to control the pressure in the place where the expansion tank is connected;
• safety valve - protects the heating system from a critical increase in pressure.

Unlike open tanks, which are installed at the top or peak point of the water supply system, devices closed type can be mounted almost anywhere.

Exception - tie-in in the immediate vicinity of the pump to avoid surges in the system. The best option– the location of the expansion tank next to heating element hot water systems.

membrane tank

This equipment is a sealed, closed container. Accordingly, it is not subject to corrosion. It has the shape of an oval or a ball, the cavity is divided by a heat-resistant rubber membrane.

The membrane tank has a number of functions:

• maintaining pressure when the pump is off;
• protection of the system against hydraulic shock;
• protection of pumping equipment;
• maintaining a certain volume of water under pressure.

Membrane tanks are divided into two types.

Replaceable membrane

The first is with a replaceable membrane. This part of the device can be dismantled through the flange. Another feature of the tank is that they exclude contact with its inside.

Accordingly, the likelihood of corrosion is reduced, and the service life is extended. Manufacturers offer both vertical and horizontal versions.

Choose suitable model you can at your own discretion, based on where the equipment will be installed. Convenience and personal aesthetic preferences play a decisive role when choosing the shape of a membrane-type expansion tank.

This does not affect functionality in any way.

Stationary diaphragm

The second type is with a stationary diaphragm. Accordingly, if the part ceases to perform its functions, the functioning is disrupted, the entire tank must be replaced.

In addition, due to the internal structure, the device is susceptible to corrosion.

To avoid this, the inside is covered with a special protective one.

But even in this case, corrosion is not completely excluded.

Tank setting

In general, the actions before setting up the tank should go in the following sequence:

• disconnecting the device from the system, it will also be enough to turn off the tap;
• relieve pressure in the system.

Last action is essential for proper tuning as system pressure can affect other readings.

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

• Pini > or = P0 + 0.3 bar.
• Having fixed and installed the received data, you can start the water. In this case, it is important to read the readings of the pressure gauge relative to the pressure Pexp. The last one is reactivation of the make-up and bringing the pressure up to Pcon. Its size is calculated by the formula:
• Pcon< или = Pкл – 0,5 бар.
• In this case, Pcl is the pressure safety valve. For private households, this figure is 3 bars.

Do not forget that in the event of a complete breakdown, you can.

Correct setting tank is the prerogative of specialists. What are the above calculations for? This data will help the user to independently configure the tank in such cases:

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

The principle of operation of the 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 moment when the indicators of air and water pressure are balanced.