The present invention relates to a system for recovering heat from the hot waste flow flow flowing out from industrial machines preferably used for textile processing, which allows to manage in a unitary and efficient manner, and in particular with a single exchanger, the regulation of the flow incoming to the machines, as a function of the previous energy exchange between such inlet flow and such outgoing flow.

Textile machines can be discontinuous or continuous.

A discontinuous machine is a machine in which loading and discharging do not occur in the same time and the temperature of the waste flow is not related to that of the loading fluid.

A continuous machine is a machine in which loading and discharging occur in the same time and the temperature of the waste flow is generally correlated to that of the loading fluid.

Currently, the operation of recovering heat from the hot liquids flowing out from continuous industrial textile machines is carried out using a heat exchanger for each machine, in particular because of the different needs of each machine in terms of flow rate and temperature of the inlet working liquid; instead, examples of recovery in discontinuous machines, in which there is no coincidence in time between discharging and loading, are not known.

The industrial machines adapted to carry out fabric processing need a working liquid at a certain temperature level, depending on the type of machine.

In particular, if the predetermined point of processing the working liquid is colder than required, the heating of the same by suitable heating means is provided. If the temperature is too high, because of various reasons, there is no way to resolve this problem, resulting in technological risks for the process. In addition, some machines work continuously, and then the operation for the re-delivery of the inlet new liquid towards the machine is continuous in nature, and especially the characteristic parameters of the incoming liquid can be adjusted as a function as those of the outgoing waste flow liquid. Other machines are designed to operate in a discontinuous way, and therefore do not need a continuous intake of incoming liquid, and especially the characteristic parameters of the incoming liquid are not correlated with those of the outgoing waste flow.

The object of the present invention is to provide a system for managing the recovery of heat from waste flow flows outgoing from various industrial machines, preferably adapted to perform processing in the textile field, and for the consequent regulation of the characteristic parameters of the new flows incoming to such machines, in a unitary manner and with a single exchanger.

Such object is achieved by a system for managing the recovery of heat from various waste flows coming respectively from various industrial machines preferably adapted to be used for textile processes, comprising:

- a heat exchanger;

- a heating conduit fluid dynamically connected to said exchanger so as to be adapted to introduce a heating flow into said exchanger;

- a source conduit and an intermediate conduit fluid dynamically connected to said exchanger, so that said source conduit is adapted to introduce a source flow into said exchanger and said intermediate conduit is adapted for the flushing of an intermediate flow deriving from said source flow and heated in said exchanger through said heating flow;

- an outlet conduit adapted for the flushing of an outlet flow;

- an inlet conduit adapted for the flushing of an inlet flow;

- various discharge conduits respectively fluid dynamically connected to said machines on one side and to said outlet conduit on the other, so as to be able to respectively transfer from said machines to said outlet conduit various waste flows respectively coming from said machines, so as to form said outlet flow;

- various load conduits fluid dynamically connected to said inlet conduit on one side and respectively to said machines on the other, so as to be able to transfer at least part of said inlet flow from said inlet conduit towards such machines respectively;

characterised in that:

- said heating conduit is fluid dynamically connected to said outlet conduit so as to be able to receive a liquid coming from said outlet flow in order to generate said heating flow;

- said inlet conduit is fluid dynamically connected to said intermediate conduit so as to be able to receive a liquid coming from said intermediate flow in order to generate said inlet flow;

- said system comprises intermediate adjustment means adapted to automatically adjust the flow rate of said source flow and/or the flow rate of said heating flow so as to correlate one to the other, based on one first flow rate measurement recorded in at least one point of said heating flow and a second flow rate measurement recorded in at least one point of said source flow;

- said system comprises various cooling channels, of which each one is in fluid dynamic communication with at least one of said load conduits and is associated with load adjustment means, which are adapted to make a cooling flow automatically lead into at least one of said load flows and are adapted to automatically adjust such cooling flow based on at least one temperature measurement recorded in at least one corresponding load flow point.

Through the configuration of the intermediate adjustment means, the flow rate values respectively of the heating flow and the source flow can be approached to each other, so as to increase the efficiency of the heat exchanger in response to the variation in the flow rates of the possible discharge flows from and/or in the load flows required by the machines. Through the cooling channels, a single load flow can be prevented from be at a temperature too hot for the corresponding machine.

The outlet conduit and the heating conduit could be two parts of a single conduit, as well as the intermediate conduit and the inlet conduit could be two parts of a single conduit.

Note that, in this application, the term liquid or liquid flow means one or more substances in the liquid state, or a flow of one or more substances in the liquid state, even if such liquid and such flow may include therein also one or more substances in the solid or gaseous state. The waste flows outgoing from industrial machines, for example, are usually dirty and therefore include therein substances in the solid state, but, however, can be considered still liquid flows.

A possible embodiment of the present invention may comprise at least one of the following aspects.

Preferably, the intermediate adjustment means are adapted to reduce the discrepancy between such flow rate of the heating flow and the flow rate of the source flow, and the load adjustment means are adapted to cool down each one of said load flows if it is too hot for the corresponding machine.

Preferably, the system comprises a logic control unit, which is adapted to ensure that the intermediate adjustment means and the load adjustment means work automatically.

Preferably, the load adjustment means are adapted to cool respectively the corresponding load flows if they are too hot for the machines respectively connected to said load conduits.

Preferably, the intermediate adjustment means comprise a first flow rate sensor for said heating flow and a second flow rate sensor for said source flow.

Preferably, the first flow rate sensor is placed on the heating conduit and the second flow rate sensor is placed on the source conduit.

Through flow sensors, it is unable to do so that the efficiency of the heat exchanger is not affected by changes in the flow rates of the discharge flows and in the flow rates required by the machines taking the inlet load flows.

Preferably, the intermediate adjustment means comprise intermediate interception means adapted to vary the flow rate of said source flow and/or said heating flow, based on at least one first flow rate measurement of said first flow rate sensor and a second flow rate measurement of said second flow rate sensor.

The intermediate interception means are preferably located on the source conduit.

The intermediate interception means preferably comprise an intermediate valve.

Preferably, the load adjustment means comprise a load temperature sensor of the corresponding load flow and adapted to record the temperature thereof in at least one point located downstream of a crossing between the cooling channel and the load conduit.

In this way, the adjustment performed by the load adjustment means is adapted to be based on the temperature measurement of the load flow downstream of the region, where the cooling flow is introduced.

Preferably, the load adjustment means comprise load interception means adapted to automatically adjust the flow rate of a cooling flow entering the corresponding load conduit, based on at least one temperature measurement of the corresponding load temperature sensor.

Through said load interception means and said load temperature sensors, the flow rate of the cooling flow entering a load flow can be correlated to the corresponding temperature.

In particular, it is unable to do so that if the temperature detected by the load temperature sensor is too high, the load interception means associated with the corresponding cooling channel increase the corresponding cooling flow so as to cool the corresponding load flow.

The load interception means preferably comprise a load valve. Preferably, the load interception means are located on the corresponding cooling channel and/or on the corresponding load conduit and/or in a crossing point between the two.

Preferably, the system comprises various expulsion channels, of which each one is in fluid dynamic communication with at least one of said load conduits and is associated with load adjustment means, which are adapted to make an expulsion flow automatically flow from the corresponding discharge flow and are adapted to automatically adjust such expulsion flow based on at least one temperature measurement recorded in at least one corresponding discharge flow point.

Preferably, the discharge adjustment means are adapted to ensure that each discharge flow is partially or totally expelled if it is too cold.

Preferably, the control logic unit is adapted to ensure that the discharge adjustment means work automatically.

Preferably, the discharge adjustment means comprise a discharge temperature sensor of the corresponding discharge flow and adapted to detect the temperature thereof in at least one point located upstream of a crossing between the corresponding expulsion channel and the corresponding discharge conduit.

Preferably, the discharge adjustment means comprise discharge interception means adapted to automatically adjust the flow rate of the expulsion flow leaving the corresponding discharge conduit, based on at least one temperature measurement of the corresponding discharge temperature sensor.

By said discharge interception means and said discharge temperature sensors, the flow rate of the expulsion flow leaving one discharge flow can be correlated to the corresponding temperature.

In particular, it is unable to do so that if the temperature sensor detects a temperature of the corresponding discharge flow to below a certain value, the flow rate of the same is decreased and/or cancelled by the discharge interception means associated with the corresponding expulsion channel. Preferably, the discharge interception means are located on the corresponding expulsion channel and/or on the corresponding discharge conduit and/or in a crossing point between the two.

The discharge interception means preferably comprise a discharge valve. Preferably, the system comprises a first tank.

Preferably, said outlet conduit is in fluid dynamic communication with said first tank so as to be adapted to make said outlet flow lead into said first tank.

Preferably, said outlet conduit is in fluid dynamic communication with said heating conduit through said first tank.

Preferably, said outlet conduit is in fluid dynamic communication with said heating conduit through at least a first pump.

In this way, one can advantageously adjust the pressure of the heating flow that is directed towards the heat exchanger.

Preferably, the first pump is adapted to withdraw fluid from said outlet flow. Preferably, the first pump is adapted to feed said heating flow.

Preferably, said first pump is adapted to withdraw liquid from said first tank.

In this way, the operation of the first pump is facilitated.

Preferably, the system comprises a second tank.

Preferably, said inlet conduit is in fluid dynamic communication with said second tank so that said inlet conduit can receive liquid incoming from said second tank.

Preferably, said intermediate conduit is in fluid dynamic communication with said inlet conduit through said second tank.

Preferably, said intermediate conduit is in fluid dynamic communication with said inlet conduit through at least a second pump.

In this way, the system can also be used for machines, which work discontinuously. In fact, in the case of discontinuous machines, the inlet flow can be adjusted according to the requests of the machines. Preferably, said second pump is adapted to withdraw liquid deriving from said intermediate flow.

Preferably, the second pump is adapted to feed said inlet flow.

Preferably, said second pump is adapted to withdraw liquid from said second tank.

Preferably, the system comprises compensating adjustment means that are adapted to create a pressure on one extreme section of at least one of said load conduits downstream of a crossing between the same and the corresponding cooling channel.

Preferably, the compensating adjustment means comprise an auxiliary flow rate sensor and auxiliary interception means adapted to operate based on at least one measurement of said auxiliary flow rate sensor. Said auxiliary interception means preferably comprise an auxiliary valve. In this way, if the auxiliary flow rate sensor detects a zero flow rate, such as in the case of a machine, which is connected to the corresponding conduit load, is discontinuous, and in that moment does not require a load flow rate, the auxiliary valve closes to create a back pressure downstream of such corresponding load conduit.

If the flow rate sensor detects a very low flow rate on a machine and a flow rate very high on another, the auxiliary valves operate automatically to ensure the feeding also to the machine that is withdrawing less volume. Preferably, the exchanger comprises a shell and tube adapted for the flushing of said heating flow, and an external conduit containing said shell and tube and adapted for the flushing of said source flow around said shell and tube.

According to another aspect, the present invention relates to a method of use of the system just described, which comprises the following steps: - a heating flow originating from the combination of various discharge flows coming from said machines respectively enters said exchanger, while a source flow enters into exchanger; - at the same time as the entry of the heating flow and the source flow into the exchanger, the intermediate adjustment means vary the flow rate of said heating flow and/or of said source flow based on at least one of a first flow rate measurement of said heating flow and a second flow rate measurement of said source flow, so that the values of such flow rates tend to approach one another;

- a inlet flow, deriving from said source flow once heated in said exchanger, creates various load flows;

- the load adjustment means vary the flow rates of the cooling flows respectively entering the corresponding load flows respectively, based on the respective temperature measurements of the corresponding load flows, so that each load flow is cooled if it is too hot for the corresponding machine.

Advantageously, this procedure of use includes a preliminary phase during which the discharge adjustment means vary the flow rates of the expulsion flows leaving the corresponding discharge flows respectively, based on the respective temperature measurements of the corresponding load flows, so that each discharge flow is partially or totally expelled if it is too cold.

The features of the present invention will be clarified from the accompanying description related to two possible embodiments of the present invention provided by way of illustration, and not limitation, of the more general claimed concepts.

The following detailed description refers to the accompanying drawings, in which

- Figure 1 is a diagram of a first possible embodiment of the present invention;

- Figure 2 is a diagram of a second possible embodiment of the present invention, with some parts cut away to better illustrate others;

- Figure 3 is a schematic sectional view of a detail of Figure 1 along the line ll-ll and according to a first embodiment; - Figure 4 is a schematic sectional view of a detail of Figure 1 along the line ll-ll and according to a second embodiment; and

- Figure 5 is a schematic view of a part of an embodiment of the present invention.

Figure 1 is a schematic illustration of a system 1 for managing the recovery of heat from various waste flows coming respectively from various industrial machines M, preferably adapted to be used for textile processes, according to a first embodiment of the present invention.

The system 1 comprises a heat exchanger 2, preferably comprising a shell and tube in which a warmer liquid flow flows, which is adapted to heat a colder liquid flow flowing around it.

The system 1 comprises an outlet conduit 3 suitable for the flushing of a outlet flow from carious industrial machines M, and an inlet conduit 4 suitable for the flushing of an inlet flow towards these industrial machines M. The output flow and the inlet flow take place, in the embodiments shown, preferably respectively according to the arrows U and E.

The system 1 comprises various discharge conduits 5 respectively fluid dynamically connected to said machines M on one side and to said outlet conduit 3 on the other, so as to be able to respectively transfer from said machines M to said outlet conduit 3 various waste flows respectively coming from said machines, so as to form said outlet flow. In the figures, only two discharge conduits 5a and 5b are shown by way of example. The discharge flows occur, in the embodiments shown, according to the arrows SC.

The system 1 comprises various load conduits 6 fluid dynamically connected to said inlet conduit 4 on one side and respectively to said machines M on the other, so as to be able to transfer at least part of said inlet flow from said inlet conduit 4 towards such machines M respectively. In the figures only two discharge conduits 6a and 6b are shown by way of example, The load flows take place, in the embodiments shown, according to the arrows C.

The system 1 comprises a heating conduit 7 fluid dynamically connected to said exchanger 2 so as to be adapted to introduce a heating flow into said exchanger 2, according to the arrow R.

The system comprises a source conduit 8 and an intermediate conduit 9, which are fluid dynamically connected to said exchanger 2. The source conduit 8 is adapted to introduce a source flow into said exchanger 2. The intermediate conduit 9 is adapted for the flushing of an intermediate flow deriving from said source flow and heated in said exchanger 2 through said heating flow.

The arrows S and I respectively indicate, in the embodiments shown, the source flow and the intermediate flow.

The system 1 comprises intermediate adjustment means adapted to automatically adjust the flow rate of said source flow and/or the flow rate of said heating flow so as to correlate one to the other, based on at least one first flow rate measurement recorded in at least one point of said heating flow and a second flow rate measurement recorded in at least one point of said source flow.

Preferably, the intermediate adjustment means are adapted to ensure that the detected value of the flow rate of the heating flow and the detected value of the flow rate of the source flow are approached to each other, so as to decrease the absolute value of the difference between these flow rates, i.e. the heating flow and the source flow, respectively.

In the embodiments shown, the intermediate adjustment means are adapted to automatically adjust the flow rate of the source flow, so as to adjust it so that the latter follows the flow rate of the heating flow.

Advantageously, the intermediate adjustment means comprise a first flow rate sensor 10r for said heating flow and a second flow rate sensor 10s for said source flow, which serve precisely to ensure that the flow rate of the source flow can be adjusted based on the difference between the two. Preferably, the intermediate adjustment means comprise intermediate interception means 1 1 s adapted to vary the flow rate of said source flow and/or said heating flow, based on at least one first flow rate measurement of said first flow rate sensor 10r and a second flow rate measurement of said second flow rate sensor 10s.

The intermediate interception means 1 1 s, in the embodiments shown, are placed on the source conduit 8 and are adapted to vary the flow rate of the source flow.

The intermediate interception means 1 1 s preferably comprise an intermediate valve 1 1 a.

The system comprises at least various cooling channels 12a and 12b, of which each one is in fluid dynamic communication with at least one of said load conduits 6a and 6b. Each of said cooling channels 12a and 12b is also associated with load adjustment means, which are adapted to make a cooling flow automatically lead into at least one of said load flows and are adapted to automatically adjust such cooling flow based on one temperature measurement recorded in at least one corresponding load flow point. The cooling flows, in the embodiments shown, take place according to the arrows F.

In the embodiments shown, each of the cooling channels 12a or 12b intersects with the corresponding load conduit 6a or 6b, respectively, at one point or node or crossing.

Advantageously, the load adjustment means comprise a load temperature sensor 13a or 13b of the corresponding load flow and adapted to record the temperature thereof in at least one point located downstream of such crossing.

Advantageously, the load adjustment means comprise load interception means 14a or 14b, respectively, adapted to adjust the flow rate of a cooling flow entering the corresponding load conduit 6a or 6b, respectively, based on at least one temperature measurement of the corresponding load temperature sensor 13a or 13b, respectively. The load adjustment means 14a or 14b advantageously comprise a load valve 14a or 14b, respectively.

Preferably, the load interception means 14a or 14b are located on the corresponding cooling channel 12a or 12b, respectively, and/or on the corresponding load conduit 6a or 6b, respectively, and/or, as shown in the figures, in a crossing point between the two.

In the embodiments shown, in particular, the load interception means comprise a three-way valve indicated with 14a or 14b and located at the crossing between the corresponding cooling channel 12a or 12b, respectively, and the corresponding load conduit 6a or 6b, respectively. As regards the load conduit 6a, if the temperature detected by the load temperature sensor 13a is too high, the load valve 14a makes sure automatically that a cooling flow arriving from the cooling channel 12a is entered into the load flow flowing in such load conduit 6a.

The same apply with regard to the load conduit 6b, the load temperature sensor 13b, the load valve 14b, and the cooling channel 12b.

Note that the presence in the figures of just two load channels 6a and 6b is purely exemplary, as the embodiments shown, and more in general the present invention, is adapted to operate also with numerous machines M. In these embodiments, there are a number of expulsion channels 15a and 12b, of which each one is in fluid dynamic communication with at least one of said discharge conduits 5a and 6b. Each of said expulsion channels 15a and 15b is also associated with load adjustment means, which are adapted to ensure that an expulsion flow is automatically drained, and are adapted to automatically adjust such expulsion flow based on one temperature measurement recorded in at least one corresponding discharge flow point. The expulsion flows, in the embodiments shown, take place according to the arrows B.

In the embodiments shown, each of the expulsion channels 15a or 15b intersects with the corresponding discharge conduit 5a or 5b, respectively, in a point or node or crossing. Advantageously, the discharge adjustment means comprise a discharge conduit temperature sensor 16a or 16b of the corresponding discharge flow and adapted to record the temperature thereof in at least one point located upstream of such crossing.

Advantageously, the discharge adjustment means comprise discharge interception means 17a or 17b adapted to adjust the flow rate of a expulsion flow leaving the corresponding discharge conduit 5a or 5b, respectively, based on at least one temperature measurement of the corresponding discharge temperature sensor 16a or 16b, respectively. Preferably, the discharge interception means 17a or 17b are located on the corresponding expulsion channel 15a or 15b, respectively, and/or on the corresponding discharge conduit 5a or 5b, respectively, and/or in a crossing point between the two.

The discharge interception means 17a and 17b preferably comprise a discharge valve.

In the embodiments shown, in particular, the discharge interception means comprise a first valve and a second valve, both indicated with 17a or 17b, one located on the expulsion conduit 15a or 15b, respectively, and the other placed on the discharge conduit 6a or 6b, respectively.

As regards the discharge conduit 5a, if the temperature detected by the discharge temperature sensor 16a is too low, the valves 17a makes sure automatically that such discharge flow is at least partially or totally expelled through the expulsion conduit 15a.

The same apply with regard to the discharge conduit 5b, the discharge temperature sensor 16b, the discharge valve 17b, and the expulsion channel 15b.

Note that the presence in the figures of just two discharge channels 5a and 6b is purely exemplary, as the embodiments shown, and more in general the present invention, is adapted to operate also with numerous machines M. The heating conduit 7 is fluid dynamically connected to the outlet conduit 3 so as to be able to receive a liquid coming from said outlet flow in order to generate said heating flow.

Preferably, the system comprises a first tank V1 .

In the embodiment shown, the outlet conduit 3 is in fluid dynamic communication with said first tank V1 so as to be adapted to make said outlet flow lead into said first tank V1 .

Preferably, said outlet conduit 3 is in fluid dynamic communication with said heating conduit 7 through said first tank V1 .

Preferably, said outlet conduit 3 is in fluid dynamic communication with said heating conduit 7 through at least a first pump P1 .

In the embodiment shown, the first pump P1 is adapted to withdraw liquid from said outlet flow.

The first pump P1 is advantageously adapted to feed said heating flow, and therefore is advantageously communicating with said heating conduit 7.

Advantageously, said first pump P1 is adapted to withdraw liquid from said first tank V1 , so as to be able to withdraw the liquid arrived from the outlet conduit and entered in the tank V1 , so that it generates the heating flow. In this sense, both the pump P1 and the first tank V1 contribute to put the outlet conduit 3 in fluid dynamic communication with the heating conduit 7. Note, however, that the heating conduit 7 and the outlet conduit 3 may be part of a single continuous conduit, and in such a case they would still be in fluid dynamic communication.

The flow rate downstream of the pump P1 is preferably related to the filling speed of the tank V1 .

The inlet conduit 4 is fluid dynamically connected to the intermediate conduit 9 so as to be able to receive a liquid coming from said intermediate flow in order to generate said inlet flow. Preferably, the system comprises a second tank V2, in particular in the embodiment shown in Figure 2. The tank V2 becomes indispensable when at least one discontinuous machine is present between the machines M. In the embodiment shown in Figure 2, the inlet conduit 4 is in fluid dynamic communication with said second tank V2 so that said inlet conduit 4 can receive liquid incoming from said second tank V2 to generate said inlet flow.

In the embodiment shown in Figure 2, the intermediate conduit 9 is in fluid dynamic communication with said inlet conduit 4 through said second tank V2.

In the embodiment shown in Figure 2, the intermediate conduit 9 is in fluid dynamic communication with said inlet conduit 4 through at least one second pump P2.

In this way, the system 1 can also be used for machines M, which work discontinuously. In fact, in the case of discontinuous machines, the inlet flow can be adjusted according to the requests of the machines M.

Preferably, said second pump P2 is adapted to withdraw liquid deriving from said intermediate flow.

Preferably, the second pump P2 is adapted to feed said inlet flow, and therefore is advantageously communicating with said inlet conduit 4.

Preferably, said second pump P2 is adapted to withdraw liquid from said second tank V2, so as to be able to withdraw the liquid arrived from the intermediate conduit 9 and entered in the tank V2, so that it generates the inlet flow.

The pump P2, in the case of the presence of discontinuous machines M, operates according to the requests thereof.

Both the pump P2 and the second tank V2 contribute to put the intermediate conduit 9 in fluid dynamic communication with the inlet conduit 4. Note, however, that the intermediate conduit 9 and the inlet conduit 4 may be part of a single continuous conduit, and in such a case they would still be in fluid dynamic communication. Advantageously, the system comprises compensating adjustment means that are adapted to automatically create a pressure on one extreme section of at least one of said discharge conduits 6a and 6b downstream of a crossing between the same and the corresponding cooling channel 12a or 12b, respectively, based on a detected flow rate of the corresponding load flow.

Preferably, the compensating adjustment means comprise an auxiliary flow rate sensor 18a or 18b, respectively, and auxiliary interception means 19a or 19b, respectively, adapted to operate based on at least one measurement of said auxiliary flow rate sensor 18a or 18b, respectively. Advantageously, the auxiliary interception means 19a or 19b, respectively, are placed downstream of the point of crossing between the corresponding cooling channel 12a or 12b, respectively, and the corresponding load channel 6a or 6b, respectively.

Preferably, said auxiliary interception means 18a or 18b comprise an auxiliary valve 18a or 18b, respectively.

If the flow rate sensor detects a zero flow rate, the auxiliary valve 19a automatically ensures to establish a certain pressure also in the corresponding load conduit 6a. In this way, if for example the machine M, fed from the load conduit 6b, requires a load flow, while the machine connected to the load conduit 6a does not require a load flow, it is possible to avoid that the whole flow rate of the inlet flow ends up unnecessarily in the load conduit 6a, the ends of which is in this case preferably at atmospheric pressure.

If the flow rate sensor 18a detects a very low flow rate on its load conduit, the system automatically adjusts the auxiliary valve 19b of the conduit to a higher flow rate so as to balance the pressures on the two ducts. In this way, it is ensured to the feeding to the both, even in case of a "open outlet"-fed branch.

The embodiment of the present invention, shown in Figure 1 , is particularly adapted to be used in the case where all the machines M are continuous. A process of use of the embodiment of the present invention shown in Figure 1 preferably comprises the following steps:

- the output flow, originated by the combination of multiple discharge flows from said machines M and arriving respectively through the discharge ducts 5a and 5b, enters into said tank V1 before passing through said outlet conduit 3;

- the liquid coming from said output flow is drawn by the pump P1 so that the heating flow is sent into the heat exchanger 2 by passing first through the heating conduit 7, while the source flow enters into said exchanger 2 by passing first through the source conduit 8;

- simultaneously with the entry of the heating flow and of the source flow into the heat exchanger 2, the intermediate valve 1 1 s automatically varies the flow rate of said source flow based on at least a first measurement of flow rate of said heating flow performed by the first sensor flow 10r and a second measurement of flow rate of said source flow performed by the second flow rate sensor 10s, so that the values of such flow rates of said heating flow and of said source flow, respectively, tend to approach each other;

- an intermediate flow, coincident with the inlet flow and deriving from said source flow, once heated in said heat exchanger 2, splits entering into the load conduits 6a and 6b, passing first through the intermediate conduit, which coincides with the inlet conduit 4;

- the load interception means 14a and 14b, respectively associated to the cooling channels 12a and 12b, automatically vary the respective flow rates of the cooling flows entering the corresponding load flows respectively, based on the respective temperature measurements performed by the respective load temperature sensors 13a and 13b, so that each of said load flows is cooled if it is too hot for the corresponding machine M.

The embodiment of the present invention shown in Figure 2 is particularly adapted to be used in the case where at least one of the machines M is discontinuous. The second pump P2 and the second tank V2 are functional to ensure that the flow rate of the inlet flow are according to the trend of the liquid demands of the machines M.

As specified above, the heat exchanger 2 is preferably of shell and tube type.

In particular, the exchanger 2 comprises a delivery conduit 22 of the incoming liquid and at least one recovery conduit 23 adapted to be traversed by the outflowing liquid.

The delivery conduit 22 is connected at the input to the source conduit 8 and at the outlet to the intermediate conduit 9. The recovery conduit 23 is advantageously arranged inside the delivery conduit 22, and is connected at the input to the heating conduit 7 downstream of the first flow rate sensor 10r, and at the output to a hydraulic conduit 28 (illustrated only in Figure 1 ).

The delivery conduit 22 and the recovery conduit 23 comprise at least two flanked longitudinal sections 24 and connection means C between the at least two longitudinal sections 24. In the example illustrated in Figures 1 and 2, there are three longitudinal sections 24 flanked two by two and connected by connecting means C.

In Figure 5, which shows one of the longitudinal sections 24 of the recovery 23 and delivery conduits 22, it can be noted that in this arrangement the connection means C from a section 24 to the another one of Figures 1 and 2 are, at each end of each section 24, the one in communication with the delivery conduit 22 and the other one with the recovery conduit 23.

In Figure 4 is shown a cross-section of the delivery 22 and recovery conduits 23, in which it can be noted that the recovery conduit 23 may advantageously comprises a plurality of recovery conduits 23' arranged inside the delivery conduit 22, so as to further reduce more the amount of dirt contained in the outflowing liquid that is deposited on the walls of the recovery conduit 23. In Figure 3 is shown another possible configuration of the delivery 22 and recovery conduits 23, such that the latter comprises a single conduit 23 inside the delivery conduit 22, which results in a structural simplification of this portion of the exchanger 2.

With reference to both the figures 3 and 4, the delivery conduit 22 is external to the recovery conduit 23 whereby the incoming liquid occupies the space around the recovery conduit. The outflowing liquid occupies the space in the recovery conduit 23, which is preferably realized by means of one (or more) pipes defining at least an inner, cylindrical and smooth wall, i.e. devoid of protuberances or projections which would hinder the outflowing liquid flow.

A washing system of the exchanger 2 is shown only in Figure 1 for sake of clarity.

In detail, cleaning means 26 are provided, which are disposed in communication with the recovery conduit 23 for the introduction of cleaning fluids in the recovery conduit 23, preferably water and lactic acid. The cleaning means 26 further comprise steam which is introduced into the recovery conduit 23 to heat said cleaning fluids.

These fluids allow to remove the residues and the fouling in contact with the surfaces of the recovery conduit 23.

To be able to perform an effective washing and possibly also a preliminary rinsing step, and/or a rinsing step after the actual washing, the cleaning means comprise input lines L for the cleaning fluids disposed in communication with the recovery conduit 23, preferably with the tank V1 In particular, a first input line L' is placed in communication with a reservoir 27 of a cleaning substance, preferably lactic acid, and has a metering pump LV suitable for dispensing the acid according to predefined metered quantities according to the type of cleaning that must be implemented. A second input line L" is placed in communication with a source of a rinsing substance, such as the water, and has a valve LV" for the controlled delivery of such substance. A third input line L'" is placed in communication with a source of steam for heating, in particular for heating the cleaning substance.

The steam input line L'" includes a system for managing the delivery of steam, provided with a valve LV" for the controlled delivery of the steam inside the tank V1 in order to maintain the temperature of the cleaning fluids within a pre-set value. In this way, a temperature sensor (not illustrated) on the conduit 7 measures the temperature of the washing fluid and activates the delivery of steam in the event that this temperature should be raised to a pre-set value. Again, the third input line L'" is preferably provided with a pressure reduction valve to delivery the steam inside the tank V1 at a pressure equal to or lower than 1 bar, thus avoiding excessive handling of the cleaning fluid (water and lactic acid) within the tank V1 .

For the purpose of being able to quickly switch from the heat recovery step to the washing step, while maintaining a certain simplicity in the structural configuration of the system, the outlet hydraulic circuit 28 (only illustrated in Figure 1 for sake of clarity) can be advantageously provided that is connected to the recovery conduit 23. The hydraulic conduct 28 comprises a recovery conduit 28a suitable for setting the recovery conduit 23 and the tank V1 in communication, and a discharge conduit 28b suitable for setting the recovery conduit 23 in communication with a discharge 29.

In order to also facilitate the automation of the washing operations, valves 30 can be provided, which are suitable for selectively setting the recovery conduit 23 in communication with the recovery conduit 28a or the discharge conduit 8b. In particular, there is provided a valve 30 on the recovery conduit 28a and a valve 30 on the discharge conduit 28b.

Again, the discharge conduit 28b has, upstream of the respective valve 10, a siphon 33 adapted to prevent the complete emptying of fluids from the recovery conduit 23. Therefore, this siphon 33 ensures to avoid, even in a condition of non-use of the exchanger 2, the emptying of the fluids from the conduit 23 while keeping the entire heat exchanger in a state of immersion.

Advantageously, the constant condition of immersion of the recovery conduit 23 prevents the formation of fouling on the internal surfaces of the recovery conduit 23 due to the presence of air and then to oxidation reactions of the pollutants present in the conduit 23 itself. Therefore, it is also maintained a certain efficiency in the heat exchange of the recovery conduit 23 due precisely to the prevention of the surface structure of the conduit.

A process of use of the embodiment of the present invention shown in Figure 2 preferably comprises the following steps:

- the output flow, originated by the combination of multiple discharge flows from said machines M and arriving respectively through the discharge ducts 5a and 5b, enters into said tank V1 before passing through said outlet conduit 3;

- the liquid coming from said output flow is drawn by the pump P1 so that the heating flow is sent into the heat exchanger 2 by passing first through the heating conduit 7, while the source flow enters into said exchanger 2 by passing first through the source conduit 8;

- simultaneously with the entry of the heating flow and of the source flow into the heat exchanger 2, the intermediate valve 1 1 s automatically varies the flow rate of said source flow based on at least a first measurement of flow rate of said heating flow performed by the first sensor flow 10r and a second measurement of flow rate of said source flow performed by the second flow rate sensor 10s, so that the values of such flow rates of said heating flow and of said source flow, respectively, tend to approach each other;

- an intermediate flow, derived from the said source flow once heated in said heat exchanger 2, passes through said intermediate conduit 9 and enters into said second tank V2;

- the second pump P2 draws the liquid from said intermediate flow, in such a way that the inlet flow is sent into the load conduits 6a and 6b passing first through the inlet conduit 4 and with a flow rate adapted to the needs of the machines M;

- the load interception means 14a and 14b, respectively associated to the cooling channels 12a and 12b, automatically vary the respective flow rates of the cooling flows entering the corresponding load flows respectively, based on the respective temperature measurements performed by the respective load temperature sensors 13a and 13b, so that each of said load flows is cooled if it is too hot for the corresponding machine M.

Preferably, before these steps, the method of use, both of the embodiment shown in Figure 1 and of that shown in Figure 2, also comprises the following step:

- On the basis of the measurements of the respective discharge temperature sensors 16a and 16b, the discharge interception means 17a and 17b, respectively associated to the expulsion channels 15a and 15b, automatically vary the flow rate of the expulsion flows leaving the corresponding discharge flows respectively, so that each each of said discharge flows is partially or totally expelled if too cold.

The present invention advantageously allows to manage in a unitary and efficient manner the heat recovery from various hot waste flows coming respectively from various industrial machines, to heat the source flow that will generate the clean load flows incoming to said machines, according to the temporal variations of both the flow rates of the actual discharge flows and the load flows required by such machines. Advantageously, the system can be used for both continuous and discontinuous machines, thus providing the heat recovery even for the machines where there is no coincidence in time between discharging and loading.

Furthermore, the process of heating the source flow by the liquid coming from the output flow, in turn originated by the combination of the discharges, is optimized through the discharge of the waste flows too cold.