Expansion tank closed

In many domestic production machines, the cooling system is similar to the heating system. A circulating pump is installed in the structure. As a rule, the expansion tanks are of an open type. However, this is not very convenient. In closed systems, membrane tanks are used. Their design, which has a relatively small size, is designed for sufficiently high temperatures. The connection is made using pipes of small diameter.

In a closed, fluid-filled system, when the water temperature rises, the hydraulic pressure tends to increase. Too high pressure can lead to failure of individual parts. Expansion tanks for heating systems are used to exclude such situations. They are used to compensate for the volume of liquid that becomes larger when heated, and any attempts to squeeze water lead to an increase in its volume.

The expansion tank of the membrane type (closed) is made in the form of a hermetically sealed metal ball or oval. The volume of water should be able to increase. The expansion tank has a two-part internal space. In one the air is pumped. The second half of the space is attached to the system. During the heating process, the air is compressed.

The expansion tank (closed) requires the installation of a pressure control nipple or a safety valve and a pressure gauge. This is necessary to prevent excess pressure. For a heating system of an autonomous type with artificial circulation, a certain pressure is established. As a rule, its value is two or four bars.

The expansion tank is installed next to the boiler. The connection is made to the return line in front of the suction pipe of the circulating pump. Great importance should be given to fixing the tank itself, because in the process of working its mass will increase significantly. The whole structure is a metal case. It can be flat or balloon type. Air is pumped into the air chamber. He is under certain pressure. The initial pressure is indicated, as a rule, in the passport to the structure. The entire volume of the unconnected expansion tank is occupied by air.

Before starting, it is necessary to set the gas charge pressure equal to the static pressure. It is set at a rate of one bar per ten meters of water column, located above the structure. As the temperature increases, water enters the water chamber, thus increasing the pressure in the air space to the pressure throughout the system. With a larger volume of coolant, a mandatory condition is control over the gas pressure in the air cavity. In this case, the expansion tank is equipped with a compressor that maintains the pressure in the air compartment at a constant level.

There is one main element in the whole construction. This element - the membrane - can be diaphragmatic or balloon type. The former are non-replaceable and are usually used in small-volume designs. In the event of failure of the balloon type membrane, it can be replaced. The advantage of this design is also the absence of contact between water and the housing. The liquid is located inside the membrane. This greatly extends the life of the entire structure.

The expansion tank has a certain volume. For its calculation, special quantities are used. The main one is the total volume in the entire heating system. If this volume is not known, then it is calculated in accordance with the boiler output and taking into account the type of heating devices.