Patent Description:
The invention relates to a separator filter for a thermal system, in particular a heating and/or cooling system.

In thermal systems comprising a primary circuit (for the generation of thermal power) and a secondary circuit (for the distribution of thermal power to utilities), each provided with one or more pumps, there can be situations in which the pumps interact determining anomalous changes in the flow rates and in the heads of the circuits. In this type of systems, a hydraulic separator is used, which is interposed between the primary circuit and the secondary circuit, in order to create a common zero-head zone between the two circuits, thus making them - at least theoretically - hydraulically independent. In this way and under ideal conditions, regardless of the number of active pumps and of the delivered flow rate, the pressure in the separator always is the same as the pre-loading pressure of the system and the flow rate circulating in each circuit exclusively depends on the pump of the circuit itself, without mutual influences between the pumps. As a consequence, in case the pump of a circuit is active and the one of the other circuit is not active, the flow in the active circuit does not induce a flow in the inactive circuit.

Known hydraulic separators generally comprise a hollow body, which, in use, is arranged vertically and is provided with four sleeves, which are arranged two by two on opposite sides of the body. Two sleeves are used for the connection to a delivery line and to a return line of the primary circuit and the other two are used for the connection to a delivery line and to a return line of the secondary circuit. Between the two pair of sleeves, namely along the a vertical middle plane of the body, there can be a partition with the function of supporting the separation of the suspended particles as well as the build-up thereof on the bottom of the body. A purge valve, which is arranged on the bottom of the body, allows impurities to be periodically purged.

Known separators suffer from some drawbacks.

Known separators cannot be inspected. Despite the purge valve, inside the body there can be a build-up of deposits that are such as to determine, over time, a significant load loss, which can jeopardize the correct operation of the separator. In this case, the separation between the primary circuit and the secondary circuit is not perfect and, therefore, there can be influences between the flow rates delivered by the pumps in the respective circuits. In particular, there can be parasite flows within a circuit even if the pump of said circuit is inactive, with a consequent alteration of the temperature available to the utilities.

Another problem, which especially arises under conditions of partial loads (small flow rates) is linked to the parasite current generated along the walls of the separator between the delivery and the return of the primary and secondary circuits, which are enabled by the different temperature of the fluids (stratification). Because of these parasite currents, a precise control of the temperature available to the utilities becomes difficult.

<CIT> discloses a separator having the features of the preamble of claim <NUM>.

The object of the invention is to provide an improved separator, which solves the aforesaid problems affecting known separators.

In order to do so, the invention provides a separator according to claim <NUM>.

According to the invention, the creation of a node, in which there is a direct connection between the input lines of the primary circuit and of the secondary circuit, and the simultaneous use of a filter inside the separator, downstream of which there is the connection between the aforesaid node and the return line of the primary circuit, ensure a zero load loss between the aforesaid lines. Therefore, the separator always is in ideal operating conditions and ensures a perfect independence between the circuits in any condition.

The invention also relates to a thermal system according to claim <NUM>.

The invention will be best understood upon perusal of the following detailed description of a preferred embodiment, which is provided by way of non-limiting example, with reference to the accompanying drawings, wherein:.

With reference to <FIG>, number <NUM> indicates, as a whole, a hydraulic separator according to the invention.

The separator <NUM> comprises a hollow body <NUM> with a vertical axis A having a substantially cylindrical lateral wall <NUM> and a bottom wall <NUM>, which preferably is bulged downwards.

The body <NUM> delimits an inner chamber <NUM> and is closed at the top by a removable cover <NUM>, which is fixed to an annular flange <NUM> radially projecting from an upper end of the lateral wall <NUM> by means of a plurality of bolts <NUM>.

The body <NUM> comprises four threaded tubular sleeves <NUM>, <NUM>, <NUM>, <NUM>, which define respective connection openings communicating with the chamber <NUM> and are arranged two (<NUM>, <NUM>) on one side of the lateral wall <NUM> and two (<NUM>, <NUM>) on the opposite side (<FIG> and <FIG>).

The sleeves <NUM>, <NUM> are arranged above the flange <NUM> and preferably are coaxial and in a diametrically opposite position relative to one another; the sleeves <NUM>, <NUM> are arranged close to the bottom wall <NUM> and preferably are coaxial and in a diametrically opposite position relative to one another.

In the example shown herein, the axes of the sleeves <NUM>, <NUM>, <NUM>, <NUM> are arranged on a common plane P (<FIG>) going through the axis A.

The body <NUM> is finally provided with a bracket <NUM>, which projects from the lateral wall <NUM> and ends with a plate <NUM>, conveniently parallel to the plane P and elongated in a horizontal direction, which is provided with holes <NUM> for the fixing to a wall or another support structure.

The cover <NUM>, which is provided with an upper handle <NUM> to help it be moved, carries an air purge valve <NUM>, which is connected to the chamber <NUM> by means of a ball shut-off valve <NUM>. The cover <NUM> is further provided with a joint <NUM> for the possible introduction of substances into the carrier fluid.

The cover <NUM> finally carries, on the inside of the chamber <NUM>, a magnet <NUM>, which projects from the cover itself along the axis A and is coated with a protection sheath <NUM>, which can be removed in order to facilitate the cleaning of the magnet.

The cover <NUM> is mounted on the flange <NUM> of the body <NUM> with the interposition of a gasket <NUM>.

The lateral wall <NUM> defines, immediately under the sleeves <NUM>, <NUM>, an annular inner flange <NUM>, which supports a filter <NUM>.

The filter <NUM>, which is shaped like a cylindrical basket, comprises a lateral wall <NUM> made of a metal net with meshes with dimensions in the range of <NUM>, a bottom wall <NUM> and an upper annular flange <NUM>, which is designed to rest against the inner flange <NUM> of the wall <NUM> of the body <NUM>.

The filter <NUM> is provided with a pair of bars <NUM> (<FIG>), which are fixed on the inside of the lateral wall <NUM> in a diametrically opposite position relative to one another. The bars <NUM> axially project upwards and end with respective ends <NUM> bent in the form of an L, which can be grabbed in order to remove and install the filter <NUM>.

The bottom wall <NUM> of the filter <NUM> has a central through hole <NUM> (<FIG>) housing, in a sliding manner, a tubular sleeve <NUM>, which projects downwards and engages a funnel-shaped upper end <NUM> of an axial duct <NUM>, which leads outwards at the centre of the bottom wall <NUM>; at the lower end <NUM> of the duct <NUM> there is housed a ball purge valve <NUM>.

The tubular sleeve <NUM> is provided, at the top, with a disc shutter <NUM>, which is designed to seal the hole <NUM> of the bottom wall <NUM> when the filter <NUM> is removed from the body <NUM>. The sleeve <NUM> and the shutter <NUM> define a normally open valve, which is designed to automatically close when the filter <NUM> is removed.

The filter <NUM> divides the inner chamber <NUM> of the body <NUM> into an upper filtering zone 5a, which houses the magnet <NUM>, and into a lower hydraulic separation zone 5b. Therefore, the integration of the filter <NUM> on the inside of the body <NUM> has the effect of definitely allowing the zone 5b to be free from impurities and of preventing it from determining a pressure drop between the sleeve <NUM> and the sleeve <NUM>.

The separator <NUM> finally comprises an interconnection kit <NUM>, which can be connected to the body <NUM> in a removable manner. The kit comprises a connection <NUM>, which can be connected to the sleeve <NUM> by means of a first intermediate rotatable dead joint <NUM>, a second connection <NUM>, which can be connected to the sleeve <NUM> by means of a second intermediate rotatable through joint <NUM>, and a tube <NUM>, which hydraulically connects the first joint <NUM> and the second joint <NUM> to one another. Therefore, in use, the sleeve <NUM> is closed by the intermediate joint <NUM>, which basically constitutes a plug, and the connection of the first joint <NUM> to the sleeve <NUM> has a mere mechanical anchoring function, whereas the joint <NUM> is hydraulically connected to the sleeve <NUM> by means of the tube <NUM> and the joint <NUM>, which define a node N of the circuit with zero head, as better described below.

The tube <NUM> has a double-elbow shape and, in the example shown herein extends behind the body <NUM> (namely, between the body <NUM> ad the plate <NUM> of the bracket <NUM>). This configuration is suited in case the pipes of the primary circuit come from the side of the sleeves <NUM>, <NUM> (from the left with reference to <FIG> and <FIG>) and the ones of the secondary circuit come from the side of the sleeves <NUM>, <NUM> (from the right with reference to <FIG> and <FIG>). However, the joint <NUM> can be connected to the sleeve <NUM> and the joint <NUM> can be connected to the sleeve <NUM> in case the pipes of the primary circuit come from the right and the ones of the secondary circuit come from the left (always with reference to <FIG> and <FIG>).

<FIG> shows the diagram of a thermal system <NUM> using the separator <NUM> according to the invention and comprising a primary circuit <NUM> and a secondary circuit <NUM>. The separator <NUM> is shown in a schematic fashion and the sole sleeves <NUM>, <NUM>, <NUM>, <NUM> are indicated, whereas the relative joints, if present, are not indicated.

The primary circuit <NUM> comprises an input line <NUM>, a pump <NUM>, a generator <NUM>, for example a boiler, and a return line <NUM>, which is mechanically connected to the sleeve <NUM>, but is hydraulically connected, as discussed above, to the sleeve <NUM> by means of the tube <NUM>. The sleeve <NUM> defines (or is connected to) a connection for the input line <NUM>.

The secondary circuit comprises an input line <NUM> connected to the sleeve <NUM> of the separator <NUM>, a pump <NUM>, at least one utility <NUM> and a return line <NUM> connected to the sleeve <NUM> of the separator <NUM>. The sleeve <NUM> defines (or is connected to) a connection for the return line <NUM>.

The return flow rate coming from the utility flows into the body <NUM> of the separator <NUM> through the sleeve <NUM>. Since the cross section of the body <NUM> is much larger than the one of the line <NUM>, the flow undergoes a sudden speed reduction, with a consequent reduction in the particle dragging speed.

The magnet <NUM>, which is arranged in the upper part of the body, holds back the impurities having magnetic features (ferrous residues, metal sludge).

The remaining particles (mud, sand) are held back by the filter <NUM>: the heavier ones precipitate towards the bottom wall <NUM> due to gravity, the lighter ones are held back on the inside through direct filtration.

The return line <NUM> of the primary circuit <NUM> and the input line <NUM> of the secondary circuit <NUM> are directly connected to one another in the node N (thanks to the tube <NUM>). The node N, in turn, is connected to the input line <NUM> of the primary circuit <NUM> through the zone 5b, which, since it is free from impurities because of what mentioned above, cannot introduce any load loss regardless of the cleaning condition of the filter.

Furthermore, since the flow flowing out of the primary circuit is directly fed to the inlet of the secondary circuit without having to go through the chamber <NUM> of the separator <NUM>, stratification phenomena and parasite currents along the walls of the body <NUM> are avoided.

This ensures that the hydraulic separation between the primary circuit <NUM> and the secondary circuit <NUM> is ideal, as evidently shown by the diagrams of <FIG>. Therefore, whatever the flow rate in the primary and secondary circuits, there is a total absence of parasite flows and of mutual influence between the pumps of the aforesaid circuits and there is no alteration of the hydraulic balances between the circuits as well as no alteration of the flow temperature available to the utilities.

<FIG> schematically show the flows in the separator in different possible operating conditions of the system.

<FIG> shows the case in which the sole primary circuit is active; in this case, there is no parasite flow in the secondary circuit.

<FIG> shows the case in which the sole secondary circuit is active; in this case, the separator <NUM> only fulfils the task of filtration of the return flow coming from the secondary circuit.

<FIG> shows the behaviour in case both the primary circuit and the secondary circuit are active and the flow rate of the primary circuit is the same as the flow rate of the secondary circuit; in this case, the separator <NUM> fulfils the task of filtration of the return flow and of direct connection between the output of the primary circuit and the input of the secondary circuit. Since there is no intersection between the flows on the inside of the body <NUM> of the separator, there are no parasite currents supported by the stratifying action of conventional separators. For this reason, the separator according to the invention can be used both for heating and for cooling purposes, with no need to change the connections of the pipes.

<FIG> shows the case in which the secondary circuit <NUM> requires a greater flow rate compared to the one provided by the primary circuit <NUM>. In this case, again, the separator fulfils the task of hydraulic separation between the circuits, ensuring the magnetic filtration of the entire flow rate coming from the secondary circuit.

Finally, <FIG> shows the opposite case in which the secondary circuit <NUM> requires a smaller flow rate compared to the one provided by the primary circuit <NUM>. The excess flow rate of the primary circuit is recirculated through the separator <NUM>, which also carries out the magnetic filtration of the entire flow rate coming from the secondary circuit.

The use of the tube <NUM> allows the physical connection of the delivery and return lines of the primary circuit to be carried out on the same side of the separator <NUM>, with evident advantages in terms of assembly easiness. Furthermore, the physical connections are identical to those of a conventional separator, which makes it easier for them to be assembled by plumbers who are used to using conventional separators.

Claim 1:
Hydraulic separator for a thermal system (<NUM>) provided with a primary circuit (<NUM>) and a secondary circuit (<NUM>), including a body (<NUM>) with a vertical axis (A), defining an inner chamber (<NUM>) and equipped with a first connection (<NUM>) for connecting to a return line (<NUM>) of the primary circuit (<NUM>), a second connection for connecting to an input line of the primary circuit (<NUM>), a third connection for connecting to a return line (<NUM>) of the secondary circuit (<NUM>) and a fourth connection (<NUM>) for connecting to an input line (<NUM>) of the secondary circuit (<NUM>), and a filter (<NUM>) housed in the said inner chamber (<NUM>) and interposed between a first zone (5a) of the inner chamber (<NUM>) communicating with the third connection (<NUM>) and a second zone (5b) of the inner chamber (<NUM>) communicating with the second and fourth connection (<NUM>, <NUM>),
characterized in that the first connection (<NUM>) and the fourth connection (<NUM>) are connected to each other through a node (N) outside said inner chamber (<NUM>).