EP2271970B1

EP2271970B1 - Hydraulic device for feeding and controlling a water stream towards users

Info

Publication number: EP2271970B1
Application number: EP08763837.5A
Authority: EP
Inventors: Umberto Bertolotti
Original assignee: IVAR SpA
Current assignee: IVAR SpA
Priority date: 2008-04-23
Filing date: 2008-04-23
Publication date: 2015-08-12
Anticipated expiration: 2028-04-23
Also published as: CN102016739B; CN102016739A; EP2271970A1; WO2009130724A1

Description

The present invention relates to a hydraulic device for feeding and controlling a stream of fluid, typically water, towards one or more users.
In particular, the present invention relates to a multifunctional hydraulic device, apt to hydraulic balance and record heat consumed by the users.
The present invention applies to hydraulic systems installed in houses, offices or buildings in general.
A specific technique required by hydraulic systems in buildings involves a correct feeding and a balanced distribution or hot or cold water towards single users, without unbalances occurring in the circuit. In the present invention and claims, the term user refers to a closed hydraulic circuit, typically comprising heat exchanging elements (e.g. radiant panels and/or radiators) so as to enable heat exchange between the fluid and one or more elements connected to the user circuit, such as air of one or more rooms and/or sanitary water.
It is preferred that, whatever the instantaneous demand of the single user for a specific use (feeding a heating or sanitary system) and whatever the user's position in the building, water available for single users always has a given flow rate and above all the general hydraulic system undergoes no unbalances that might affect the other users causing an excess or a shortage of water.
Known hydraulic devices comprise a delivery branch, generally provided with a three-way valve for adjusting by way of a command given by an ambient thermostat the flow rate towards the user, or better for allowing or preventing the passage of water towards the user, a return branch through which hot water gets back to the boiler, and a bypass duct connecting the delivery branch to the return branch, through which duct water not demanded by the user circulates, i.e. when the three-way valve is closed. Generally, such devices further comprise balancing valves, apt to adjust the water flow rate both in the bypass circuit and in the main water circuit (i.e. the one including the user), and an instrument for recording consumed calories cooperating with two heat probes placed in the delivery branch and in the return branch and with a flow meter for measuring the amount of water used by the user, mounted upstream from the bypass duct. Similar devices are often highly complex from a structural point of view and also bulky, since they have several additional components beyond the main ones referred to above.
Moreover, the device setting and system adjustment step is very laborious and requires the intervention of qualified and expert technicians and/or the use of expensive or complex instruments.
As a matter of fact, after adjusting the desired maximum flow rate requested by the users, normally the flow rate in the bypass duct is set by placing the balancing valve of the bypass duct in the correct position as can be obtained by reading suitable tables and diagrams containing indexes corresponding to given flow rates or related pressure drops.
Relevant prior art is disclosed by EP 1 772 677 A2 .
Disadvantageously, the adjustment of these devices by reading diagrams and tables firstly requires such diagrams to be available to the technician, and secondly the technician to have a certain experience and familiarity in reading and correctly interpreting data obtained from diagrams and from measuring instruments installed in the device.
In this context the technical task of the present invention is to propose a hydraulic device for feeding and controlling a water stream towards users that is free from the drawbacks mentioned above.
In particular, an aim of the present invention is to propose a hydraulic device for feeding and controlling a water stream towards users that enables a fast and easy installation, without using auxiliary instruments or diagrams.
A further aim of the present invention is to propose a hydraulic device for feeding and controlling a water stream towards users that is structurally simple and little bulky.
The present invention is defined by claims 1 and 12.
According to the present invention, the technical task and the aims as described are achieved by a hydraulic device for feeding and controlling a water stream towards users comprising the technical characteristics listed in one or more of the appended claims.
In an aspect, the invention relates to a method according to any of the claims 12 to 15, characterized in that the device (1) comprises a shut valve (15) placed along said first hydraulic path (5) for opening or closing said first hydraulic path (5).
In an aspect, the invention relates to a method according to any of the claims 14 to 15 or to the latter aspect above, characterized in that the device (1) comprises a further shut valve (16) placed along said second (12) hydraulic path for opening or closing said second hydraulic path (12).
In an aspect, the invention relates to a method according to any of the claims 12 to 15 or to one of the two latter aspects above, characterized in that the device (1) comprises a first and a second temperature probe (18a, 18b) associated to the delivery branch (2) and to the return branch (3), respectively, and apt to cooperate with the measuring instrument (4) for detecting the caloric consumption of said user circuit.
Further characteristics and advantages of the present invention will be more evident from the indicative, and therefore non-limiting, description of a preferred but not exclusive embodiment of a hydraulic device for feeding and controlling a water stream towards users, as shown in the accompanying drawings, in which:

Figure 1 shows a section of a hydraulic device for feeding and controlling a water stream towards users according to the present invention, in a first operating configuration of normal use;
Figure 2 shows a section of a hydraulic device according to the present invention, in a second operating configuration of normal use;
Figure 3 shows a section of a hydraulic device according to the present invention, in an operating configuration of setting.

With reference to the accompanying figures, the numeral 1 globally refers to a hydraulic device according to the present invention.
Inside the hydraulic paths of the device 1 preferably flows hot and/or cold water, apt to supply a final user, e.g. a closed hydraulic circuit in a flat of a block of flats, with heating or sanitary water.
The hydraulic device 1 comprises a delivery branch 2 through which water can be sent to the final user (not shown, but schematically connectable to the device on the right side of the figures), and a return branch 3 through which water gets back to the general system and/or to a boiler, not shown but schematically connectable to the device on the left side of the figures by way of suitable pipes.
Both the delivery branch 2 and the return branch 3 have each a corresponding inlet section 2a, 3a and a corresponding outlet section 2b, 3b. The inlet section 2a of the delivery branch 2 is connectable to a pipe coming from the general system (typically the general system of the building, including the boiler), whereas the inlet section 3a of the return branch 3 is connectable to a pipe coming from the user. Conversely, the outlet section 2b of the return branch 2 is connectable to a pipe directed to the user, whereas the outlet section 3b of the return branch 3 is connectable to a pipe directed to the general system or to the boiler.
The return branch 3 can be advantageously coupled with a measuring instrument 4, apt to measure the instantaneous flow rate and/or the user's calorie consumption.
Preferably, the device 1 also comprises said measuring instrument 4, by which both the instantaneous flow rate getting through the return branch 3 can be quantified and the calorie energy consumption can be recorded.
As can be seen in the accompanying figures, the device 1 further comprises at least one first hydraulic path 5 putting the delivery branch 2 in fluid communication with the return branch 3.
Preferably, the device 1 comprises a shut-off valve 6 associated to the delivery branch 2. The shut-off valve 6 can be operated between a first operating configuration for opening the delivery branch 2, in which the whole water stream getting into the section 2a gets through the whole delivery branch 2 and gets out from the section 2b reaching the final user, and a second operating configuration for closing the delivery branch 2, in which the water stream getting into the section 2a is diverted from the delivery branch 2 towards the return branch 3, without getting through the final use. For simplicity's sake, in the following description the first operating opening configuration will be explicitly referred to as "ON" position and the second operating closing configuration will be referred to as "OFF" position.
The shut-off valve 6 preferably comprises a shutter 6a, shutter adjustment members and a suitable seat placed on the delivery branch 2 for the components of the valve itself. In particular, in the present description and claims, the term 'valve seat' generally refers to the parts of the device 1 shaped so as to house and/or cooperate with the remaining components of the valve itself. The shutter 6a is movable (parallel to its longitudinal development) between two positions corresponding to the first and second operating configurations above, respectively. The shutter has two seals, preferably O-rings, with a circumferential development and longitudinally spaced apart, which are apt to engage a respective gap on the delivery branch 2 and to ensure the tightness of the shutter 6a in the respective gaps. In the OFF position (Figs. 2 and 3), the shutter engages a gap corresponding to a cross section of the delivery branch 2, so as to close said delivery branch 2. Simultaneously, the shutter releases a second gap corresponding to a cross section of the first hydraulic path 5, which extends laterally from the delivery branch 2. In the ON position (Fig. 1), the shutter operates conversely.
Advantageously, said shut-off valve 6 is a motorized, preferably three-way, zone valve, and although it can also take intermediate positions between ON and OFF positions, it is advantageously operated only between the two extreme operating configurations mentioned above.
The shut-off valve 6 is preferably placed between the inlet section 2a and the outlet section 2b, thus dividing the delivery branch 2 into an initial portion 2c and an end portion 2d.
From the delivery branch 2, in particular on the shut-off valve 6, starts a connection duct 7 included within the first hydraulic path 5.
The latter fits into the recturn. branch 3 on a connection area 8 of said return branch 3, placed upstream, considering the flowing direction R of the return water stream, from a portion 9 of the return branch 3 configured so as to couple directly with the measuring instrument 4, so that the latter lies downstream from the connection area 8 of the return branch 3 with the first hydraulic path 5.
Preferably, the device 1 further comprises at least one first balancing valve 10 placed on the delivery branch 2, preferably between the inlet section 2a and the outlet section 2b. Said valve 10, whose use will be explained in the following, is apt to balance the flow rate in the primary circuit, i.e. in the circuit comprising the delivery branch 2, the use and the return branch 3.
The balancing valve 10 preferably comprises a shutter 10a, shutter adjustment members (typically of manual type) and a suitable seat placed on the delivery branch 2 for the remaining components of the valve itself. Advantageously, said seat of the balancing valve 10 of the primary circuit is placed downstream from the seat of the shut-off valve 6, considering the feeding direction M of the delivery water stream.
The device 1 preferably also comprises a second balancing valve 11, associated to the first hydraulic path 5. The balancing valve 11 preferably comprises a shutter 11 a, shutter adjustment members (typically of manual type) and a suitable seat placed on the first hydraulic path 5 for the remaining components of the valve itself. In particular, the seat of the shutter of the balancing valve 11 is placed on the connection duct 7, e.g. on an outlet section 7b of said duct.
The second balancing valve 11 is apt to adjust the flow rate of water flowing within a recirculation or bypass circuit, when the shut-off valve is in the OFF position. Advantageously, said balancing valve 11 is a valve with manual adjustment.
The shutter 11a is movable so as to get near and away from the outlet section 7b of the duct 7, so as to control the flow rate of fluid in said duct 7. Advantageously, the shutter 11 a has on its circumference a seal, preferably an O-ring.
Also the use of this second balancing valve 11 will be explained in detail in the following.
The device 1 preferably comprises a shut valve 15 associated to the first hydraulic path 5, e.g. a ball valve. The shut valve 15 preferably comprises a shutter 15a, shutter adjustment members (typically of manual type) and a suitable seat placed on the first hydraulic path 5 for the remaining components of the valve itself. In particular, the seat of the shutter of the shut valve 15 is placed on the first hydraulic path 5 so as to open or close the duct.
According to the preferred illustrated embodiment, the device 1 preferably comprises a second hydraulic path 12, which connects the delivery branch 2 and the return branch 3.
Preferably, as shown in the accompanying figures, the second hydraulic path 12 extends from the delivery branch 2 and fits into the return branch 3, in a connection area 13 of the return branch 3 placed downstream, considering the flowing direction R of the return water stream, from the portion 9 configured so as to be coupled directly with the measuring instrument 4, so that the latter lies between the connection area 8 with the first hydraulic path and the connection area 13 with the second hydraulic path.
The first 5 and the second 12 hydraulic path preferably coincide at least on a passage gap between the delivery branch 2 and the two hydraulic paths. More preferably, they coincide at least on the connection duct 7 and separate from each other downstream (following the flowing direction of the fluid in the bypass) from the seat of the balancing valve 11, e.g. directly downstream from the outlet section 7b of the connection duct 7.
In operation, the first hydraulic path 5 is preferably a setting circuit for the device 1. The second hydraulic path 12 is preferably a water recirculation or bypass circuit, which is active when no water supply to the user is demanded. Water flows through the first and/or the second path when the shut-off valve 6 is in OFF position and the shutter 6a closes completely the passage gap between the initial portion 2c and the end portion 2d of the delivery branch 2, though leaving the connection gap between the initial portion 2c of the delivery branch 2 and the connection duct 7 open. Water is thus deviated towards the first 5 and/or the second 12 hydraulic path.
When water has reached the outlet section 7b of the connection duct 7, it gets along (in opposite directions in the embodiment shown in the figures) either the first 5 or the second 12 hydraulic path, as shown in Figures 2 and 3 by the arrows P1 and P2.
The device 1 preferably comprises a shut valve 16 associated to the second hydraulic path 12, e.g. a ball valve. The shut valve 16 preferably comprises a shutter 16a, shutter adjustment members (typically of manual type) and a suitable seat placed on the second hydraulic path 12 for the remaining components of the valve itself. In particular, the seat of the shutter of the shut valve 16 is placed on the second hydraulic path 12 so as to open or close the duct.
The second hydraulic path 12 preferably comprises, along its development, a throttling 17. The latter is configured so as to reproduce the same pressure drop (K_v) as the measuring instrument 4.
The device 1 further comprises at least two seats 18 for temperature probes 18a and 18b, a first seat being located on the delivery branch for a first probe 18a and a second seat on the return branch for a second probe 18b. In particular, the seat for the first probe 18a is placed upstream from the seat of the shut-off valve 6, considering the flowing direction M of the delivery stream. The seat for the second probe 18b is located downstream form the measuring instrument 4, considering the flowing direction R of the return water stream. Advantageously, the device 1 also comprises said temperature probes 18a and 18b. The temperature values detected by the probes 18a and 18b are used to detect the temperature difference between delivery stream and return stream, thus obtaining, crossing these values with the instantaneous flow rate values obtained from the measuring instrument 4, the caloric consumption of the system.
Advantageously, the device 1 comprises at least one seat for a non-return valve 19 placed on the delivery branch 2, preferably downstream from the seats of the shut-off valve 6 and of the first balancing valve 10 with respect to the flowing direction (M) of the fluid stream in the delivery branch 2, e.g. on the outlet section 2b of said branch. Advantageously, the device 1 also comprises said non-return valve 19.
Advantageously, there is also at least one seat for a filter 20, placed on the return branch 3 upstream from the portion 9 for housing the measuring instrument 4, considering the direction R of the return stream, e.g. (Figures) upstream from the connection area 8 between the first hydraulic path 5 and the return branch 3. Advantageously, the device 1 also comprises said filter 20.
Advantageously, at least the delivery branch 2, the seat of the shut-off valve 6, the seat of the first balancing valve 10, the seat of the second balancing valve 11 and at least one portion of the first hydraulic path 5 are obtained as one piece 30, preferably of melted metal. Preferably, also the first seat for the first temperature probe 18a and/or the seat for the non-return valve 19 are obtained from said body 30. Advantageously, at least the connection duct 7 and/or a portion of the second hydraulic path 12 are also obtained from said piece 30. Preferably, at least one portion (or the whole) of the shutter 6a of the shut-off valve and/or of the shutter 11 a of the second balancing valve 11 and/or of the shutter 10a of the first balancing valve 10 and/or of the first probe 18a and/or of the non-return valve 19 are housed in said body 30. During installation, the device should be set and the balancing valves 10 and 11 should be adjusted so as to balance the whole system and always ensure a correct supply of water stream.
After connecting the device 1 (including at least the measuring instrument 4) to the use and to the main system, e.g. by connecting the inlet section 2a of the delivery branch 2 and the outlet section 3b of the return branch 3 to the pipes of the main system, and the inlet section 3a and the outlet section 2b to the users pipes, the following steps have to be executed.
First of all, the primary circuit has to be balanced, i.e. the one including the delivery branch, the user and the return branch and which is active during the normal operation of the heating system of the single user. In other words, the flow rate of water getting through the delivery branch 2, the use and the return branch 3 has to be adjusted.
During this first step, the shut-off valve 6 has to be opened, i.e. placed on ON, so that the connection duct 7 is closed and the delivery stream flows only through the whole delivery branch 2. In other words, the shutter 6a of the shut-off valve 6 closes the inlet to the first hydraulic path 5 (connection duct 7).
After getting through the use, water gets back to the return branch 3. Advantageously, during this step the whole return stream has to be let through only the whole return branch, e.g. without dispersing towards the first hydraulic path 5. To this purpose the first hydraulic path 5 has to be closed for the return stream, e.g. by closing at least the ball valve 15.
If also the second hydraulic path 12 is present, as in the preferred illustrated embodiment, the respective ball valve 16 can be closed, as an alternative (Figure 1) or integration to closing the valve 15, still with the aim of closing the first hydraulic path 5 to the return stream. As a matter of fact, by closing at least one of the ball valves 15 and 16 the hydraulic path made up of the separate portions of the hydraulic paths 5 and 12 is bypassed for the return stream, so as to ensure that the return water stream only gets through the return branch 3.
The primary circuit can now be balanced by acting upon the first balancing valve 10, either opening or closing it (varying the position of the shutter 10a and therefore varying the flow rate of the stream getting through the primary circuit) up to a position in which the maximum flow rate allowed for that specific system or the maximum flow rate desired for that specific user can be read on the measuring instrument 4, which in this step acts as instantaneous flow meter. Preferably, the first balancing valve 10 is blocked in said position, e.g. by lead sealing.
After balancing the primary circuit, the recirculation or bypass circuit has to be balanced.
With reference to the figures, during the setting step the recirculation or bypass circuit is simulated by the first hydraulic path 5. Conversely, during the normal use of the device, the real recirculation or bypass circuit is represented by the second hydraulic path 12. In the case provided for in the present invention, in which the second hydraulic path 12 is absent, the first hydraulic path 5 acts both as setting circuit and as recirculation circuit in two separate steps.
During the bypass balancing step, the shut-off valve 6 is closed, i.e. placed on OFF. Thus, the shutter 6a bypasses the end portion 2d of the delivery branch 2. Still in accordance with the preferred embodiment shown in the figures, the ball valve 16 of the second hydraulic path 12 is closed and the ball valve 15 of the first hydraulic path 5 is opened. Water flows from the first portion 2c of the delivery branch 2 to the connection duct 7 and from there it can flow only through the first hydraulic path 5 and from there return to the boiler or to the main system getting through the measuring instrument 4 (Figure 3).
Here again, said measuring instrument 4 act as instantaneous flow meter, similarly to the previous explanation.
By acting upon the second balancing valve 11, the position of the shutter 11a is adjusted and therefore the flow rate getting through the recirculation or bypass circuit is varied, up to a position in which an instantaneous flow rate of recirculation water corresponding to a second predefined value can be read on the measuring instrument 4.
Said value can be advantageously the maximum flow rate allowed for that specific system or the maximum flow rate desired for that specific user, as in the previous balancing operation, or it can be a higher or lower value, e.g. 60% of said maximum value.
Once the balancing valve 11 is adjusted, it is now preferable to block it, e.g. by lead sealing, so as to prevent unintentional and/or unwanted shifts of the latter from its optimal operating position. The device 1, and therefore the system, are now ready for correct operation.
To this purpose, the ball valve 15 of the first hydraulic path 5 is closed, which path can also be no longer used from now on if also the second hydraulic path 12 is present. Conversely, the ball valve 16 of the second hydraulic path 12 is preferably opened. It is also preferable to block by lead sealing the ball valve 15 and/or the ball valve 16 so as to prevent tamperings with the device. In the preferred embodiment, the first hydraulic path 5 is only a setting circuit, whereas the second hydraulic path 12 is the normal recirculation or bypass circuit.
During normal operation, in order to supply water to the users the shut-off valve 6 has to be opened (ON position) so as to bypass the second hydraulic path 12, i.e. the recirculation path. Conversely, when water supply is no longer necessary, the shut-off valve 6 is switched to the closing or OFF position (Figure 2) and the water stream flows through the second hydraulic path 12, getting into the outlet section 3b of the delivery branch 3, thus bypassing the user and preferably also the measuring instrument 4.
Since recirculation water, returning to the boiler, does not get through the measuring instrument 4, the water stream does not undergo any pressure drop (K_v), which would occur if it got through the measuring instrument 4, and therefore the same pressure drop has preferably to be recreated by means of said throttling 17.
It should also be noted that in the embodiment of the present invention without the branch 12, the measuring instrument 4 records a water stream, but to such stream is associated a temperature difference (between the positions 18a and 18b) that is practically of no value, and therefore no energy consumption. The invention achieves the designed aims as well as important advantages.
The use of a similar device enables an adjustment of said device and a balancing of the system in a simple and fast manner, without any auxiliary instruments such as diagrams or tables.
Moreover, the installation of the device according to the present invention and the setting thereof can also be executed by generic technicians, without the need for a deep technical basic knowledge, aimed above all at reading and interpreting diagrams.
Eventually, the device is structurally simple, light and little bulky, also thanks to the integration of the flow meter and of the heat recorder into one measuring instrument that can be coupled on the return branch. Finally, the device is cheap as far as manufacturing and installation are concerned.

Claims

A hydraulic device (1) for feeding and controlling a fluid stream towards a use circuit, comprising:
a delivery branch (2), apt to be connected to said use circuit so as to send said stream to said use circuit,

a return branch (3), apt to be connected to said user circuit so as to receive said stream from said user circuit, and apt to be coupled with a measuring instrument (4) of the instantaneous flow rate of said stream in said return branch (3),

a first hydraulic path (5) putting said delivery branch (2) in fluid communication with said return branch (3),

a first seat, placed on the delivery branch (2), of a shut-off valve (6), the latter being operable between a first operating configuration in which it allows the stream to get through the delivery branch (2) so as to reach said use circuit, and a second operating configuration in which it diverts the stream from said delivery branch (2) towards the return branch (3) through at least one portion of said first hydraulic path (5), without getting rough said use circuit, characterised in that

a second seat is provided, placed on the delivery branch (2), of a first balancing valve (10), and a third seat, is provided, placed on the first hydraulic path (5), of a second balancing valve (11), and in that

said first hydraulic path (5) fits into the return branch (3) in a connection area (8) placed upstream, with respect to the flowing direction (R) of the stream in the return branch, from a portion (9) of said return branch (3) intended to be coupled directly with said measuring instrument (4).
The device according to claim 1, characterized in that it comprises said measuring instrument (4) coupled directly with said portion (9) of the return branch (3) downstream from the connection area (8) with the first hydraulic path (5), considering the flowing direction (R) of the stream in the return branch (3).
The device according to claim 1 or 2, characterized in that it comprises a second hydraulic path (12) putting said delivery branch (2) in fluid communication with said return branch (3), wherein at least one portion of the second hydraulic path is separate from the first hydraulic path (5) and from said users circuit.
The device according to claim 3, characterized in that said second hydraulic path (12) connects the delivery branch (2) to an area (13) of the return branch (3) placed downstream, with respect to the flowing direction (R) of the stream in the return branch (3), from said portion (9) of the return branch (3).
The device according to claim 4, characterized in that said first (5) and said second (12) hydraulic path connect to each other at least in a connection section (7b) by which said third seat of the second balancing valve (11) lies.
The device according to claim 3 or 4 or 5, characterized in that it comprises a connection duct (7) extending from the delivery branch (2) on said first seat of the shut-off valve (6), wherein said connection duct (7) is part both of the first (5) and of the second (12) hydraulic path and wherein said third seat of the second balancing valve (11) lies level with said connection duct (7).
The device according to one of the claims 3 to 6, characterized in that said second hydraulic path (12) is configured so as to reproduce a pressure drop corresponding to the pressure drop of the combination of said first hydraulic path (5) and of said measuring instrument (4).
The device according to any one of the claims 3 to 7, characterized in that each of said first (5) and said second (12) hydraulic path has a respective seat of a respective shut valve (15, 16) associated thereto along its development.
The device according to any one of the preceding claims, characterized in that said second seat of said first balancing valve (10) is placed downstream from said first seat of said shut-off valve (6), with respect to the flowing direction (M) of the stream in the delivery branch (2).
The device according to any one of the preceding claims, characterized in that it comprises at least one first (18a) and one second (18b) seat for a respective temperature probe, the first seat (18a) being placed on the delivery branch (2) and the second seat (18b) being positioned on the return branch (3).
The device according to any one of the preceding claims, characterized in that said delivery branch (2), said first seat of said shut-off valve (6), said second seat of said first balancing valve (10), said third seat of said second balancing valve (11) and at least one portion of said first hydraulic path (5) are obtained as one only piece (30).
A method for setting a device for feeding and controlling a fluid stream according to one or more of the claims 1 to 11, wherein the device comprises said shut-off valve (6), said first balancing valve (10), said second balancing valve (11) and said measuring instrument (4), including the following steps:
- positioning the shut-off valve (6) in the first operating configuration, so that the stream gets through the whole delivery branch (2) and reaches the use circuit and, once it has got through the use circuit, it returns to said return branch (3), wherein the whole return stream gets only through the return branch (3); and

- adjusting the first balancing valve (10) in a position by which said measuring instrument (4) detects an instantaneous flow rate corresponding to a first predefined flow rate value,
characterized in that it further comprises the following steps:
- positioning the shut-off valve (6) in the second operating configuration, so that the stream is wholly deviated from the delivery branch (2) and only gets through the first hydraulic path (5) until it reaches the return branch (3); and

- adjusting the second balancing valve (11) in a respective position by which said measuring instrument (4) detects an instantaneous flow rate corresponding to a second predefined flow rate value.
The method according to claim 12, characterized in that during the step of adjusting the first balancing valve (10), the first hydraulic path (5) is kept close for the return stream, so that the return stream from the use circuit only gets wholly through the return branch (3).
The method according to claim 12 or 13, characterized In that the device comprises a second hydraulic path (5) putting said delivery branch (2) in fluid communication with said return branch (3), fitting into said return branch (3) in an area (13) of the return branch (3) located downstream, with respect to the flowing direction (R) of the stream in the return branch (3), of said portion (9) of the return branch (3), and in that during the step of adjusting the second balancing valve (11) said second hydraulic path (12) is closed for said stream diverted from the delivery branch (2), so that said diverted stream only flows in the first hydraulic path (5).
The method according to claim 14, characterized in that it comprises the next step of closing the first hydraulic path (5) and of opening the second hydraulic path (12), so that the stream only flows in the second hydraulic path (12) when the shut-off valve (6) is in the second operating configuration.