Patent Description:
Said machines comprise a product containing element in which the product is contained and stirred with a stirrer. These machines also comprise a refrigeration system integrated in the machine to allow thermally processing the product to be dispensed.

There are prior art refrigeration systems in which a heat exchanger fluid circulates. Generally speaking, the refrigeration system comprises a compressor, which increases the pressure of the heat exchanger fluid, a heat exchanger, which draws heat from the heat exchanger fluid, exchanging it with the outside environment, an element for reducing the pressure (for example, a throttle valve) which reduces the pressure of the heat exchanger fluid and an evaporator which draws heat from the product to be dispensed to transfer it to the heat exchanger fluid.

The cooling capacity of the refrigeration system is influenced by the temperature of the ambient surroundings.

If the outside ambient temperature is high, the heat exchanger would be able to exchange a reduced quantity of heat with the outside environment at the evaporator.

The refrigeration systems generally comprise a fan or a turbine with the heat exchanger in order to cool it. The heat exchangers made in this way are referred to as air condensers.

The fan (or turbine) in the air condensers guarantees the operation of the machine, allowing the heat exchange between the heat exchanger fluid and the air.

However, the air condensers may have several drawbacks linked especially with high temperature conditions of the outside environment.

In effect, in the case of a high temperature of the outside environment, the fans of the air condensers must operate at higher speeds to allow an adequate heat exchange of the heat exchanger fluid with the outside environment and can therefore be very noisy.

Document <CIT> shows a machine for processing liquid or semi-liquid food products including a containing element for containing the product to be dispensed; a stirrer for stirring the product to be dispensed; a heat exchanger fluid flowing in a circuit in a direction of circulation through an evaporator, a compressor, a condenser and a pressure reducing element; a fan rotating about an axis of rotation to force an air flow towards the condenser; a control unit connected to the fan to control the fan through a speed signal; a temperature sensor, located downstream of the condenser in the circulation direction to detect a condensation temperature and configured to send to the control unit a temperature signal as a function of which the control unit generates the speed signal. Document <CIT> shows a machine for making and dispensing cold or ice beverages, such as cool drinks, slushes, sorbets and the like, comprising at least: a containment and processing tank for the product to be dispensed which has a front wall, which is equipped at the bottom of it with a dispensing mouth for dispensing the beverage, a dispenser, located at the beverage dispensing mouth and able to be turned on or off to allow the beverage to be dispensed; a thermal treatment cylinder located inside the containment tank; a stirrer located outside an outer surface of said thermal treatment cylinder and adapted to rotate about a respective axis of rotation; a refrigerating plant comprising a first exchanger, a second heat exchanger, a pressure reducing unit and a compressor, the first heat exchanger being located inside said thermal treatment cylinder, a containment compartment for the second heat exchanger, a pressure reducing unit and a compressor.

A further drawback is represented by the heat released by the air condenser into the room where the cooling machine is situated.

The main drawback caused by the high temperatures of the outside environment, if air condensers are used, is a significant reduction in the performance of the refrigeration unit.

The aim of the invention is to provide a machine for processing liquid and semi-liquid food products which overcomes the above-mentioned drawbacks of the prior art and a method for food processing in said machine.

More specifically, the aim of this disclosure is to provide a machine for processing liquid and semi-liquid food products which is capable of functioning efficiently under all ambient conditions.

The technical features of the invention, with reference to the above-mentioned aims, are clearly described in the claims below and its advantages are more apparent from the detailed description which follows, with reference to the accompanying drawings which illustrate a preferred non-limiting example embodiment of the invention:.

With reference to the accompanying drawings, the numeral <NUM> denotes a machine for making and dispensing liquid or semi-liquid food products according to this invention.

The machine <NUM> may allow the production of different types of liquid or semi-liquid products, such as, for example, ice creams, sorbets, yogurts, custards, etc..

The primary heat exchanger fluid passes through the closed circuit <NUM> in the following order: the evaporator <NUM>, the compressor <NUM>; the at least one first air condenser <NUM> and the throttle element <NUM>.

The machine <NUM> further comprises a control unit U.

The refrigeration system <NUM> of the machine <NUM> further comprises, according to the invention:.

Also according to the invention, the control unit U is configured to drive the regulating means <NUM> in such a way as to regulate the flow of primary heat exchanger fluid in the first and in the second condenser <NUM>, <NUM> as a function of an operating parameter O of the machine <NUM>.

The regulating means <NUM> are shown in <FIG>, <FIG>, <FIG>, <FIG> with a "butterfly" symbol and in <FIG>, <FIG> with a small circle.

It should be noted that inside the closed circuit <NUM> the primary heat exchanger fluid passes in succession: the evaporator <NUM>, the compressor <NUM>; the at least one first air condenser <NUM> and the throttle element <NUM>. According to this direction of circulation, the expression "upstream" means everything that precedes, in the circuit, a predetermined point/element; the expression "downstream" means all that follows, in the circuit, a predetermined point/element.

It should be noted that the expression "regulating means" is used to mean elements which allow the flow of the primary heat exchanger fluid to be varied (continuously, discretely, or of the ON-OFF type, that is, between two end values of zero flow and maximum flow).

According to an embodiment, the regulating means <NUM> are located upstream of the first condenser <NUM>.

According to another embodiment, the regulating means <NUM> are located downstream of the first condenser <NUM>.

According to another embodiment, the regulating means <NUM> are located downstream of the second condenser <NUM>.

According to a particular embodiment, the regulating means <NUM> are located upstream of both the first condenser <NUM> and the second condenser <NUM>.

According to another particular embodiment, the regulating means <NUM> are located downstream of both the first condenser <NUM> and the second condenser <NUM>.

According to an embodiment, the regulating means <NUM> comprise at least one two-way valve.

According to another embodiment, the regulating means <NUM> comprise at least one three-way valve.

Advantageously, the regulating means <NUM> make it possible to operate the refrigeration system <NUM> in three different ways:.

According to a preferred embodiment, the evaporator <NUM> is operatively coupled to the container <NUM>, thus allowing heat to be exchanged between the primary heat exchanger fluid and the product being processed inside the container <NUM>.

According to an embodiment, the evaporator <NUM> and the containing element <NUM> have a partition wall <NUM> in common. In particular, the partition wall <NUM> has a surface in contact with the primary heat exchanger fluid and a further surface in contact with the product to be dispensed.

According to this configuration, the walls of the container <NUM>, since they are closest to the evaporator <NUM>, are subject to possible formation of ice.

Preferably, the stirrer <NUM> has blades designed to prevent formation of ice on the inside surface of the container <NUM>; in effect, during rotation of the stirrer <NUM>, the blades are designed to scrape the inside surface of the container <NUM>. According to another embodiment, the stirrer <NUM> is a screw feeder. According to an embodiment, the first air condenser <NUM> comprises a fan <NUM>.

The first condenser <NUM> also comprises a finned structure, coupled to the closed circuit <NUM>, designed to allow the heat exchange surface between the primary heat exchanger fluid and the surrounding air to be increased. The fan <NUM> is rotated by an electric motor (not illustrated).

The purpose of the fan <NUM> is to cool the primary heat exchanger fluid which passes through the first condenser <NUM> allowing said primary heat exchanger fluid to increase the quantity of heat exchanged with the environment.

The refrigeration system <NUM> of the machine <NUM> comprises a second condenser <NUM> operating with a secondary heat exchanger fluid (for example, water or a mixture of water). This type of condenser allows the heat exchange to occur between primary heat exchanger fluid and secondary heat exchanger fluid. The heat exchange between the primary heat exchanger fluid and the secondary heat exchanger fluid occurs without direct contact between the two since they flow inside separate circuits. In particular, the primary heat exchanger fluid and the secondary heat exchanger fluid may be in the same current or counter-current. According to an embodiment, the second condenser <NUM> is a plate heat exchanger.

According to another embodiment, the second condenser <NUM> is a shell heat exchanger.

According to an embodiment, the second condenser <NUM> is a concentric tube heat exchanger.

The secondary heat exchanger fluid used in the second condenser <NUM> may flow in a secondary circuit <NUM> (illustrated in <FIG>) so as to be recirculated and cooled to continue to be able to exchange heat with the primary heat exchanger fluid of the closed circuit <NUM>. In particular, for this purpose, the second condenser <NUM> may be coupled to at least one cooling tower <NUM> (with natural circulation or forced circulation, that is to say, provided with fans to favour the heat exchange between the secondary heat exchanger fluid and the surrounding air).

Advantageously, the use of a condenser operating with a secondary heat exchanger fluid guarantees a better thermodynamic efficiency with respect to only use of an air condenser.

Moreover, advantageously, use of a second condenser <NUM> operating with a secondary heat exchanger fluid significantly reduces the noise due to the fan of the air condensers, especially when the fan operates in overload conditions.

Preferably, the control unit U is connected (to command and/or control) with one or more of the following components of the machine <NUM>:.

The control unit U is programmed to generate, receive and process control signals.

The control unit U is programmed to generate drive signals as a function of the control signals.

The control unit U is programmed to send said control signals to the components of the machine <NUM> to which the control unit U is connected and which is designed to control.

Describing in more detail the control mode of the machine <NUM>, it should be noted that the control unit U is configured to rotate the stirrer <NUM> about the mixing axis A by controlling the actuator <NUM>. According to a preferred embodiment, the actuator <NUM> is an electric motor.

The control unit U is configured to drive the regulating means <NUM> in such a way as to regulate the flow of primary heat exchanger fluid in the first and in the second condenser <NUM>, <NUM> as a function of an operating parameter O of the machine <NUM>.

In particular, the expression "operating parameter" is used to mean any machine state or operating parameter which can be associated with processing (for example a parameter relating to the state of components, ingredients and/or products).

Preferably, the operating parameter is a parameter relating to the state of the ingredients and/or of the products or, alternatively, a parameter relating to the state of the refrigeration system (preferably the state of the primary heat exchanger fluid at one or more points of the system). The control unit U allows, depending on the operating parameter O, the control of the machine <NUM> in an optimum manner.

The control unit U may, according to an aspect, be configured for regulating the speed of rotation of the fan <NUM> of the first air condenser <NUM> as a function of the operating parameter O.

Regulating the speed of rotation of the fan of an air condenser guarantees the optimum operation of the air condenser.

In an embodiment, the control unit U is configured to drive the regulating means <NUM> in such a way as to allow the primary heat exchanger fluid to flow in the first condenser <NUM> and/or in the second condenser <NUM> as a function of the type of product.

In one embodiment, the machine <NUM> comprises a user interface <NUM>. According to an embodiment, the user interface <NUM> is connected to the control unit U to allow a user to enter the value of the operating parameter O (relating to the state of components, ingredients and/or products).

According to an embodiment, the user interface <NUM> connected to the control unit U allows the type of product to be inserted so as to consequently regulate the regulating means <NUM>.

The machine <NUM>, according to an embodiment, comprises at least one sensor <NUM> by means of which it is able to measure the operating parameter O.

Advantageously, detecting the operating parameter O by means of the sensor <NUM> makes it possible to keep the machine <NUM> monitored.

Another advantage of detecting the operating parameter O by means of the sensor <NUM> is that of making the control of the machine <NUM> automated.

The operating parameter O detected by the sensor <NUM> may be:.

According to an embodiment, the machine <NUM> comprises at least two sensors <NUM> designed to measure different operating parameters O.

According to one aspect, the control unit U is configured to drive the regulating means <NUM> in such a way as to allow the primary heat exchanger fluid to flow only in the first condenser <NUM> if the temperature or the pressure detected by the sensor <NUM> is less than a first predetermined value.

Preferably, if the first predetermined value is a temperature value, the first predetermined value is between <NUM> and <NUM>.

Still more preferably, if the first predetermined value is a temperature value, the first predetermined value is between <NUM> and <NUM> (preferably <NUM>).

Advantageously, activating only the first condenser <NUM> if the temperature or the pressure detected is less than the first predetermined value guarantees that the refrigeration to operate in an optimum manner. Advantageously, for these temperature and/or pressure values the first condenser <NUM> has a lower energy consumption than the second condenser <NUM>.

According to an aspect, the control unit U is configured to drive the regulating means <NUM> in such a way as to allow the primary heat exchanger fluid to flow only in the first condenser <NUM> if the temperature or the pressure detected by the sensor <NUM> is less than a first predetermined value.

Preferably, if the second predetermined value is a temperature value, the second predetermined value is between <NUM> and <NUM>.

Still more preferably, if the second predetermined value is a temperature value, the second predetermined value is between <NUM> and <NUM> (preferably <NUM>).

Advantageously, activating only the second condenser <NUM> if the temperature detected is greater than the second predetermined value guarantees that the refrigeration system operates in an optimum manner, because the second condenser <NUM>, having a thermal efficiency greater than that of the first condenser <NUM>, allows a more efficient heat exchange in these conditions.

According to an aspect, the control unit U is configured to drive the regulating means <NUM>, so as to choke (that is, subdivide) the primary heat exchanger fluid in the first condenser <NUM> and in the second condenser <NUM> if the temperature detected by the sensor <NUM> is greater than or equal to the first predetermined value and less than or equal to the second predetermined value.

Preferably, the choking is a function of the temperature: in effect, if the temperature detected by the sensor <NUM> is greater than or equal to the first predetermined value and less than or equal to the second predetermined value, the control unit U is configured to control the regulating means <NUM>, so as to choke (that is, divide) the flow of primary heat exchanger fluid in the first condenser <NUM> and in the second condenser <NUM> according to a proportion equal to a difference between the temperature/pressure value detected by the sensor <NUM> and the first predetermined temperature/pressure value divided by the difference between the second and the first predetermined temperature/pressure value.

In other words, following said criterion, if the temperature is close to the first predetermined value the choking of the heat exchanger fluid means that a greater quantity of fluid flows in the first condenser; Vice versa, if the temperature/pressure is close to the second predetermined value the choking of the heat exchanger fluid means that a greater quantity of fluid flows into the second condenser <NUM>. According to an aspect, the regulating means <NUM> allow a flow of primary heat exchanger fluid entering the second condenser <NUM> proportional to the temperature or pressure detected by the sensor <NUM>.

Advantageously, simultaneously activating the first condenser <NUM> and the second condenser <NUM> if the temperature or the pressure detected is greater than or equal to the first predetermined value and less than or equal to the second predetermined value, guarantees that the refrigeration system operates in an optimum manner, since it allows the positive aspects of both types of condenser to be used, which are optimum under the specific conditions.

With reference to the case in which the parameter detected is a pressure value at the outlet from the first and second condenser (<NUM>, <NUM>), according to an aspect, the regulating means <NUM> are configured so as to regulate the flow of primary heat exchanger fluid in the first and in the second condenser (<NUM>, <NUM>) as a function of the pressure value detected as follows:.

If the primary heat exchanger fluid is an HFO coolant such as R-452A, the first pressure value is <NUM> bar (<NUM> MPa) and the second pressure value is <NUM> bar (<NUM> MPa)
It should be noted that, more generally speaking, if the primary heat exchanger fluid is a different coolant from R-452A, the first and the second pressure values may be different from those indicated.

According to one aspect, the control unit U is configured to drive the regulating means <NUM> in such a way as to allow the primary heat exchanger fluid to flow in the first condenser <NUM> and/or in the second condenser <NUM> as a function of the type of product.

According to an embodiment, the sensor <NUM> detects the type of product processed by the machine <NUM> so as to consequently regulate the regulating means <NUM>.

According to another embodiment, the type of product is introduced (that is, communicated to the control unit U) by means of a user interface <NUM>.

Advantageously, regulating the flow of primary heat exchanger fluid in the first condenser <NUM> and/or in the second condenser <NUM> as a function of the type of product guarantees the optimum characteristics for the desired product are obtained; in effect, it is possible to use - in advance - actively in the refrigeration system the first condenser <NUM> and/or the second condenser <NUM> on the basis of the characteristics and specific features of the product being processed.

According to another aspect, the control unit U is configured to drive the regulating means <NUM> in such a way as to allow the primary heat exchanger fluid to flow in the first condenser <NUM> and/or in the second condenser <NUM> as a function of the step in the operation of the machine <NUM>. The expression "operating step" means the processing time and/or the type of processing being performed on the finished product. For example, the term "operating step" may mean the mixing step, the mixing and cooling step (simultaneously), etc..

According to an embodiment of the refrigeration system <NUM> of the machine <NUM>,
the second condenser <NUM> is disposed parallel to the first air condenser <NUM>.

Advantageously, the configuration in parallel of the first and second condensers <NUM>, <NUM> allows the two condensers to be simultaneously activated in the presence of predetermined operating conditions and to exchange the heat necessary to guarantee the optimum operation of the refrigeration system.

According to an embodiment, the closed circuit <NUM> comprises a first leg <NUM> and a second leg <NUM>.

According to an aspect, the first condenser <NUM> is positioned in the first leg <NUM>.

According to an aspect, the second condenser <NUM> is positioned in the second leg <NUM>.

According to an embodiment, the first leg <NUM> is positioned in parallel to the second leg <NUM>.

According to an embodiment, the first leg <NUM> is positioned in series with the second leg <NUM>.

According to an embodiment, the closed circuit <NUM>, in the configuration in series of the leg <NUM> and of the leg <NUM>, comprises a first bypass leg <NUM> (associated with the leg <NUM>) which allows the primary heat exchanger fluid to pass beyond the first condenser <NUM> allowing the flow solely in the second condenser <NUM>.

According to another embodiment, the closed circuit <NUM>, in the configuration in series of the leg <NUM> and of the leg <NUM>, comprises the first bypass leg <NUM> which allows the primary heat exchanger fluid to pass beyond the first condenser <NUM> and a second bypass leg <NUM> (associated with the leg <NUM>) which allows the primary heat exchanger fluid to pass beyond the second condenser <NUM>.

According to an embodiment, the closed circuit <NUM>, in the configuration in series of the leg <NUM> and of the leg <NUM>, comprises the second bypass leg <NUM> which allows the primary heat exchanger fluid to pass beyond the second condenser <NUM>.

According to one aspect, the regulating means <NUM> comprise at least one valve which allows regulating the flow of primary heat exchanger fluid in the first condenser <NUM> and/or in the second condenser <NUM>.

According to an aspect, the regulating means <NUM> comprise at least one two-way and/or three-way valve.

The expression "two-way valve" means a valve provided with a valve body (with an inlet and an outlet) and a shutter, the movement of which regulates the internal passageway and chokes the flow of the primary heat exchanger fluid through it.

The expression "three-way valve" means a valve provided with a valve body and a shutter which regulates the flow of the primary heat exchanger fluid inside it. These three-way valves may be partly open or closed and be provided with an inlet and two outlets or with two inlets and an outlet. According to an embodiment (<FIG>), considering an arrangement in series of the first leg <NUM> and the second leg <NUM>, the regulating means <NUM> comprise a three-way valve v1 positioned upstream or downstream (not illustrated) of the first condenser <NUM> and a three-way valve v2 upstream or downstream (not illustrated) of the second condenser <NUM>.

According to a further embodiment (<FIG>), considering an arrangement in series of the first leg <NUM> and of the second leg <NUM>, the regulating means <NUM> comprise a two-way valve v3 positioned on the first leg <NUM> upstream or downstream (not illustrated) of the first condenser <NUM>, a two-way valve v4 on the first bypass leg <NUM>, a two-way valve v5 positioned on the second leg <NUM> upstream or downstream (not illustrated) of the second condenser <NUM>, a two-way valve v6 on the second bypass leg <NUM>.

According to an embodiment (not illustrated), considering an arrangement in series of the first leg <NUM> and of the second leg <NUM>, the regulating means <NUM> comprise a three-way valve positioned upstream or downstream of the first condenser <NUM>, a two-way valve positioned on the second leg <NUM> upstream or downstream of the second condenser <NUM> and a two-way valve on the second bypass leg <NUM>.

According to an embodiment (not illustrated), considering an arrangement in series of the first leg <NUM> and of the second leg <NUM>, the regulating means <NUM> comprise a two-way valve positioned on the first leg <NUM> upstream or downstream of the first condenser <NUM>, a two-way valve on the first bypass leg <NUM> and a three-way valve upstream or downstream of the second condenser <NUM>.

According to an embodiment, considering an arrangement in parallel of the first leg <NUM> and of the second leg <NUM>, the regulating means <NUM> comprise a three-way valve v1 upstream (illustrated in <FIG>) or downstream (not illustrated) of the first and second condensers (<NUM>, <NUM>).

According to an embodiment, considering an arrangement in parallel of the first leg <NUM> and of the second leg <NUM>, the regulating means <NUM> comprise a two-way valve v3 on the first leg <NUM> and a two-way valve v5 on the second leg <NUM>, positioned upstream (illustrated in <FIG>) or downstream (not illustrated) of the first condenser <NUM> and of the second condenser <NUM>, respectively.

With reference in particular to <FIG> and <FIG>, according to an embodiment, the container <NUM> is a thermal treatment tank 2A. In this embodiment, the machine <NUM> comprises a dispensing duct <NUM>. The dispensing duct <NUM> is configured to connect the thermal treatment tank 2A to the dispenser <NUM>.

According to an embodiment, illustrated in <FIG>, the machine <NUM> comprises a further container <NUM>. The further container <NUM> is connected to the container <NUM> by a filling duct <NUM>. The further container <NUM> is in contact with the further evaporator 102A.

In this embodiment, the machine <NUM> comprises a second actuator 5A. According to this embodiment, the machine <NUM> comprises a second stirrer 4A. The second actuator 5A is connected to the second stirrer 4A for rotating it and mixing a product contained in the further container <NUM>. According to this embodiment, the machine <NUM> preferably also comprises a pump for transferring the product from the further container <NUM>' to the container <NUM>.

The control unit U is configured for rotating the second stirrer 4A about the further mixing axis B by controlling the second actuator 5A. According to another aspect of the invention, a method is also defined for food processing of a food mixture, in particular a pasteurizing method. According to an aspect, the method comprises a step of preparing a base mixture.

According to an aspect, the method comprises a step of heating a base mixture (preferably inside the container <NUM> and/or the thermal treatment tank 2A) for a predetermined heating time. According to a first aspect, the heating occurs at <NUM> and <NUM>; preferably, said heating time is greater than or equal to <NUM> minutes.

According to an embodiment, the step of heating a base mixture comprises an alternating heating between the container <NUM> and the thermal treatment tank 2A.

According to an aspect, the method comprises a step of cooling said base mixture subjected to the rest step (preferably inside the container <NUM> and/or the thermal treatment tank 2A).

According to an embodiment, the base mixture is cooled to a temperature of between <NUM> and <NUM>.

According to the invention, during the heating step the first heat exchanger fluid is made to flow in the second condenser <NUM>.

According to the invention, during the step of cooling said base mixture, the first heat exchanger fluid flows in the second condenser <NUM>.

In other words, the first heat exchanger fluid starts to flow in the second condenser <NUM> before the step of cooling the base mixture.

The flow of the first heat exchanger fluid inside the second condenser <NUM> is interrupted when the base mixture reaches the desired temperature. Advantageously, in this way, during the more critical steps of the pasteurizing process the second condenser <NUM> is used, having a greater effectiveness.

Claim 1:
A machine (<NUM>) for processing liquid or semi-liquid food products, comprising:
- a container (<NUM>) holding the product to be dispensed and provided with a dispenser (<NUM>) for the product;
- a stirrer (<NUM>), located inside the container (<NUM>), the stirrer (<NUM>) rotating about a mixing axis (A) to mix the product to be dispensed;
- an actuator (<NUM>) connected to the stirrer (<NUM>) to set the stirrer (<NUM>) in rotation about the mixing axis (A);
- a refrigeration system (<NUM>), comprising: a closed circuit (<NUM>) configured to circulate a primary heat exchanger fluid, an evaporator (<NUM>) associated with the container (<NUM>), a compressor (<NUM>), at least one first air condenser (<NUM>) and a throttle element (<NUM>), the primary heat exchanger fluid flowing along the closed circuit (<NUM>) through the following, in succession: the evaporator (<NUM>), the compressor (<NUM>); the at least one first air condenser (<NUM>) and the throttle element (<NUM>);
- a control unit (U); the machine (<NUM>) being characterized in that the refrigeration system (<NUM>) also comprises:
- at least one second condenser (<NUM>) in which the primary heat exchanger fluid and a secondary heat exchanger fluid flow and which is configured to allow heat exchange between the primary heat exchanger fluid and the secondary heat exchanger fluid, the second condenser (<NUM>) being located downstream of the compressor (<NUM>);
regulating means (<NUM>) for regulating the flow of the primary heat exchanger fluid and operating on the first condenser (<NUM>) and on the second condenser (<NUM>) to regulate the flow of fluid in the first condenser (<NUM>) and in the second condenser (<NUM>), respectively, and in that the control unit (U) is configured to drive the regulating means (<NUM>) in such a way as to regulate the flow of primary heat exchanger fluid in the first and in the second condenser (<NUM>, <NUM>) as a function of an operating parameter (O) of the machine (<NUM>), wherein the primary heat exchanger fluid and the secondary heat exchanger fluid flow inside two separate circuits.