Which expansion tank to choose for cold water supply: membrane or with a diaphragm
Today it is difficult to surprise anyone with an autonomous water supply. This system is very convenient and practical, but for its uninterrupted operation additional devices are very often used, about which an ordinary person may not even guess. One such element is an expansion tank for cold water supply. In the modern market of water supply there are many different models of such products. So, so as not to make a mistake in choosing such a device, you need to understand, on what the principle of its work is based.
Design features and functionality
The main purpose of expansion tanks is maintaining a stable pressure level in an autonomous cold water supply system. Closed type membrane device is most often used in water supply systems.
This product resembles a tank, inside which the membrane is mounted, made of rubber and divides it into two separate chambers for air and water. After starting the system with the help of an electric pump, the water part of the tank is filled. In turn, the air chamber begins to lose its volume. In this case, the less air remains, the more pressure is injected.
Have a moment, when the pressure in the air chamber exceeds the specified parameters, the pumping equipment will be switched off automatically. In turn, the pump will only be switched on if that is the case, when the pressure level in the expansion tank drops below the minimum value. In this case, the cycles of starting and stopping the equipment occur automatically.
For convenience, many models of membrane expansion tanks are equipped with a manometer for pressure control. Also, modern devices have the ability to adjust the operating range to the parameters, appropriate to the consumer. Installation of an expansion tank in the cold water supply system provides the following functions:
- maintaining the set pressure level when the pump is not running;
- protection of the autonomous water supply system from unforeseen water hammer, which can be provoked by a voltage drop in the mains or the formation of air plugs in the pipeline;
- maintaining a certain amount of water under constant pressure;
- additional protection of the pump against wear.
Installation of expansion tanks for cold water supply allows for low consumption of water resources, in general do not use pumping equipment, and cover the need with fluid, accumulated in the tank.
Expansion tank with replaceable membrane
The main distinguishing feature of such equipment is the ability to change the membrane as it wears. To do this, it is simply removed through a special flange device, fixed with several bolts. It is important to consider, that in tanks of large volumes for the purpose of stabilization of a membrane it in addition fastens the back party to a nipple.
Another feature of this product is that, that liquid, falling into the tank, is inside the membrane, which prevents contact with the inner walls of the tank. Due to this, the metal of the device body remains protected against corrosion, which significantly increases its service life. At the same time, models are presented as vertical on store shelves, and horizontal type.
Expansion tank with diaphragm
A feature of this device is the division of the tank into two separate tanks with a rigid diaphragm. Therefore in case of its failure it is necessary to change all product completely. In such a container, in the part with liquid there is a direct contact of water with the metal case of the device, which leads to the formation of corrosion.
To solve this problem, the inner walls of the device are opened with special dyes. However, this protection is short-lived and over time, the case still rusts. The same, as well as expansion tanks with a removable membrane model with a diaphragm happen vertical or horizontal.
How not to make a mistake with the choice of device?
In the first place, choosing expansion membrane tanks for cold water supply, you need to consider their volume. In addition, we should not forget about such factors, affecting basic device parameters:
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the number of residents of the house use an autonomous water supply system;
- number of water intake points, which in addition to the shower or faucet in the sink include a dishwasher or washing machine and other appliances, used in everyday life;
- the possibility of simultaneous use of water resources by several consumers;
- limit values of the number of starts and stops of the electric pump within one hour.
According to experts, the choice of expansion tank for cold water should be based, based on the following standard indicators:
- if the water in the house is used by a family of no more than three people, and pumping equipment produces 2 cube. meters of liquid per hour is better to prefer tanks with a volume of up to 24 l;
- if in private or suburban housing lives from 5 to 7 man, and the pump feeds to 3,5 cube. meters for an hour mount an expansion tank of 50 liters;
- if the number of inhabitants exceeds 10 persons and installed powerful 5 cubic pump, then it is advisable to use an expansion tank with a capacity of c 100 l.
In the process of choosing the appropriate model of the membrane expansion tank for cold water supply must take into account that, that the smaller the size of the tank, the more often the pumping equipment is switched on and off. Also use a small tank leads to sharp pressure drops in the water supply system. In addition, such a device must accumulate a certain supply of water resources. It is only on the basis of these parameters that the volume of the expansion tank should be selected.
You should also know, that in most designs of a tank the possibility of installation of additional tanks for water is put. At the same time, everything can be improved without interruption in the work of the main water supply system. After installing an additional tank, the total volume of the tank will be the sum of the tanks used.
In addition to the technical parameters when choosing an expansion tank for cold water supply you need to pay attention to the manufacturer. In the pursuit of savings, you can buy a product, which constantly breaking down, and the homeowner will spend money on its repair.
Most often, low-quality materials are used to reduce the cost of finished products. Of particular importance is the quality of rubber used to make the membrane. This affects not only the service life of the membrane tank, but also on water safety parameters, coming from him into the house.
If you buy a device with replaceable membranes, you need to find out the cost of spare parts. Very often unscrupulous producers for profit cost of replaceable parts artificially inflated. In this situation, you should think about buying a model from another company. Often large manufacturers are willing to take responsibility for their products, since reputation is for them in the first place. Therefore, it is advisable to prefer models of expansion tanks of well-known brands.
Independent installation of an expansion tank
All models of expansion tanks are shared into two main groups, which are determined by the method of connection to the cold water supply. Models of vertical and horizontal construction are presented on the market. There are no special differences in the design of such devices. The main features are the placement of water pipes in the room, where the equipment is installed. At the same time in the course of installation of a membrane tank it is necessary to adhere certain recommendations of specialists:
- The diaphragm expansion tank must be installed on site, to which there is free access. This is required for regular maintenance of equipment.
- It is important to provide for the possibility of dismantling the connecting pipes in order to replace or repair the tank in case of breakage.
- It is important to consider, that the diameter of the connecting pipes must correspond to the inlet pipes of the expansion tank.
- Be sure to ground it when installing the device, which reduces the likelihood of electrolytic corrosion.
Installation of the membrane expansion tank is carried out from the suction side of the pumping equipment. There should be no additional elements on the section between the pump and the tank, able to make hydraulic resistance into the water supply system.
Expansion tanks are an integral part of any stand-alone cold water supply system. Thanks to this device, the required level of pressure in the water supply is maintained, prevents premature wear of pumping equipment and preserves a certain supply of water resources. However, this can only be achieved with the right choice and installation of the device.
