Expansion tank for heating. The expansion tank of the heating system

Each water heating system is characterized byspecified capacity. Therefore, when creating it, it is important to remember that as the temperature rises, the liquid expands, and accordingly, the hydraulic pressure inside any enclosed space increases significantly. To avoid excessive increase and prevent possible accidents, an expansion tank for heating is installed in each system. It can be open or closed.

Purpose of the container

To understand all the functions that are performed by thethe tank, it is necessary to know that the water circulating in the heating system can not be compressed. When heated, its actual density decreases, which leads to an increase in the occupied volume. Therefore, without a special capacity, which will leave the excess liquid, you can not do. And the expansion tank of the heating system performs several functions at once. It takes an excessive amount of water released during the heating process, allowing you to maintain a constant hydraulic pressure. If the temperature drops or a slight leakage of liquid from the specified container is restored, the required volume in the system is restored. In addition, the tank is also designed to collect air generated during the heating of water.

Types of containers

Specialists distinguish two types of expansionTanks: open and closed. Immediately it is worth noting that the first option is now considered obsolete, but it is still used in many homes. An open expansion tank for heating is a tank connected by its bottom to the pipe. The hotter the water in the system, the higher the level rises. Install such a tank, usually above the top of the heating system, and place it in most cases in the attics of houses. In this case, its walls are covered with insulating material in order to prevent heat losses. The use of open tanks leads to the oxidation of the liquid by oxygen, which causes the corrosion of pipes and radiators from inside. The lid on the open-type expansion tank is not needed, but it can be put to protect it from getting debris.

The closed type of containers is considered more modern. These tanks are a sealed capsule, they can be made in the form of an oval or a ball. Their main advantage is the absence of contact between the liquid and the surrounding air. Due to this, water does not evaporate. Moreover, when using a closed type tank, there is no risk that the liquid level rises so much that it can pour out of the tank and ruin the finish of the walls and the floor of the room.

Classification of closed containers

When choosing expansion tanks,that they differ depending on the gas filler, the composition of the membrane and the principle of its location. The purchased container can be filled with ordinary air, nitrogen-containing mixture or other more rare filler. Membranes of tanks are of the following types:

- of natural butyl rubber, they provide the best thermal resistance;

- from ethylene-propylene rubber, are the most modern variant, are used in systems of both heating and water supply;

- of durable heat-resistant rubber, the cheapest type that is often found in products from China.

Also, the expansion tank for heating canbe equipped with an irreplaceable, replaceable or pear-shaped membrane. The first version is equipped with a special clamping ring, which ensures long-term use of this equipment, allowing to maintain the constant required pressure. In this case, the diaphragm does not stretch, but rolls over the walls of the tank, increasing the reliability of the structure.

Replaceable membrane is better used in largesystems, where a large amount of filling is possible. In such tanks, it is located on both sides between the flanges and when the container is filled with liquid, it remains immobile.

The pear-shaped replaceable membrane is attached only to the upper flange. If an excessive amount of liquid is ingested, it rests on the sides of the tank, evenly distributing the load.

Rules for selecting the tank

Before acquiring a container it is important to find out the generalvolume of the system. The expansion tank for heating must contain at least 10% of the heat carrier. In this case, it is necessary to take into account the volume of radiators, pipes and the boiler itself. Experts in selecting the optimal option take into account a greater number of indicators, among which not only the amount of liquid, but also the operating temperature, static and maximum pressure in the system.

Having ascertained the necessary volume of the tank, it is possible to proceed to its selection and pay attention to other indicators, such as gas filler, membrane material and its location.

Installation or replacement

If you just start installing the systemheating or decided that you need to replace the expansion tank, it is worth learning about some of the features of its installation. So, a closed container can be placed in any place, but the most functional area for it is a return. The optimal location will be the area between the circulation pump and the boiler itself.

The tank is connected to the system withusing a pipe that is equipped with a ball valve. In order for the membrane to take excess liquid without problems, the pressure in the vessel must be at least 0.2 atmosphere lower than in the system itself. You should also be aware that the release of the plant gas, be it air or liquid nitrogen, is prohibited.

Cost of equipment

Many when selecting the tanks are not looking atwhat principle they work for, not on their volume, but on value. But to save on this equipment is not worth it, because the safety and reliability of the heat supply system will depend on which particular expansion tank is installed. The price for the desired option, of course, may seem to you inflated, but it is better to spend once and never to know what is wrong with the selection of capacity. The cost will depend on the volume, on the type of membrane installed. It can be in the range of one to ten to twelve thousand rubles.