EXPANSION TANK WITH HEAT ACCUMULATION DESCRIPTION

The present patent concerns hydraulic systems for heating and hot water production, and more specifically it concerns a new expansion tank with heat accumul ati on/ storage .

Hot water production systems can use various sources for heating water, such as boilers with gas burners, air/water heat pumps, or other renewable sources such as solar radiation or geothermal energy.

Hydraulic systems normally include at least one expansion and compensation tank, which has the task of compensating for variations in water volume, and is normally made up of two caps, an upper cap and a lower cap, joined together in such a way as to define an internal volume. Said internal volume is divided into two parts by a membrane, wherein the upper part, or water section, is in hydraulic communication with the system and is intended to contain part of the water contained in the system, while the lower part, or gas section, is filled with gas. The membrane is elastic and adapts to the volume/pressure variation within said water section.

Hydraulic systems are also connected to various user units, such as radiators or underfloor heating pipes, etc.

Hydraulic systems often also include at least one buffer tank, that is, a technical water storage tank, which serves for storing the excess heat produced by the sources, for example a boiler or an air/water heat pump, in the form of hot water which is made available according to the requirements of the system.

A buffer tank usually comprises at least one inlet line and at least one outlet line. Buffer tanks containing a heat exchange coil are also known, in which, for example, water coming from a solar thermal system circulates. The subject of the present patent is a new type of expansion tank with a thermal flywheel, which thus serves both the function of a normal expansion tank and that of a buffer tank or storage tank.

The new expansion tank comprises a tank internally divided into two volumes by at least one fixed partition. A first volume, which therefore has fixed dimensions, is intended to be connected to the hydraulic system and to contain water, acting as a storage tank.

The second volume is in turn divided into two parts by means of an elastic membrane, wherein a first part, or water section, is intended to be hydraulically connected to the hydraulic system and filled with water from the system, while the second part, or gas section, is intended to be filled with gas at a predetermined pressure. The volume of said water section therefore varies according to the variations in the volume of the water circulating in the system, which are compensated for by the elastic membrane and by corresponding variations in the volume of the gas section.

Said water section is in hydraulic communication with said first volume, for example by means of a simple hole made in said fixed partition between said first volume and said second volume.

A single device, therefore, integrates both the functions of a normal storage tank and the functions of a normal expansion tank.

The new expansion tank with thermal flywheel can be conveniently installed in a hydraulic heating and hot sanitary water production system.

The system in which the new expansion tank with thermal flywheel is installed comprises: at least one hot water production device such as, for example, an air/water heat pump or a solar thermal system or a boiler or the like; a circuit for water circulation, connected to said at least one hot water production device; at least one user unit connected to said circuit such as, for example, one or more radiators and/or an underfloor heating circuit or the like; said at least one expansion tank with thermal flywheel, connected to said hydraulic circuit and suited to receive the incoming hot water from said at least one hot water production device and/or the water returning from said user units, and to convey water to said one or more user units and/or to said at least one hot water production device.

The characteristics of the new expansion tank with thermal flywheel and of the system including the invention are clarified in greater detail in the following description making reference to the drawing that is attached hereto by way of nonlimiting example.

Figure 1 shows a sectional view of the new expansion tank with thermal flywheel (1), provided with a membrane (7) in a first position determined by a given pressure value inside the water section (62), while Figure 2 shows a sectional view of the same expansion tank (1) shown in Figure 1, where the membrane (7) is in a second position, determined by a higher pressure value inside the water section (62).

In a preferred, particularly effective solution, the new expansion tank with thermal flywheel (1) comprises: an upper cap (2), an intermediate cap (3), joined to said upper cap (2) in such a way as to define a first volume (4) intended to contain water; a lower cap (5), externally joined to said intermediate cap (3), and wherein a second volume (6) is defined between the side (31) of the intermediate cap (3) and the side (51) of the lower cap (5), said second volume (6) being in turn divided into two parts (61, 62) by at least one elastic membrane (7). Said intermediate cap (3) thus acts as a separating element between the first volume (4), where the water storage takes place, and the second volume (6), where the volume compensation of the system’s water takes place.

The part of the volume defined between said membrane (7) and said lower cap (5), or gas section (61), is intended to be filled with gas, while the part of the volume defined between said membrane (7) and said intermediate cap (3), or water section (62), is intended to be filled with water.

For this purpose, according to the invention, the side (31) of said intermediate cap (3) is provided with at least one opening that places said first volume (4) in communication with said water section (62), whose volume is adaptable thanks to the presence of the membrane (7).

A preloading valve (52) is mounted on the side (51) of the lower cap (5) to adjust the pressure value inside said gas section.

At least two fittings for connection to the hydraulic system, respectively for the inlet of water into said first volume and for the outlet of water from said first volume (4), are mounted on the sides (21) of said upper cap (2) and/or of said intermediate cap (3).

The figure shows that, for example, four fittings (22, 23, 32, 33) can be provided, two for the inlet of water into the first volume (4), two for the outlet of water from the first volume (4).

At least said upper cap (2) and said intermediate cap (3) have heat-insulated sides (21, 31). In the preferred solution, shown for example in Figures 1 and 2, the inside of the tank (1) is heat-insulated and includes, for example, a heat insulating outer casing (8) that encloses it entirely.

In the preferred solution, all the sides of the expansion tank with thermal flywheel, and thus also said lower cap (5), are insulated.

In the new expansion tank, the air volume can vary between 10 and 30% and the water volume can vary between 90 and 70%.

In essence, the tank (1) has an overall volume intended to be filled with water and resulting from the union of the first fixed volume (4) with the water section (62), whose volume is variable and adaptable. The new tank (1) thus simultaneously serves the two functions of thermal storage tank and expansion tank.

Therefore, with reference to the above description and the attached drawings, the following claims are made.