Automatic beverage preparation machine equipped with an electromagnetic induction continuous fluid heater

Abstract

In an automatic beverage preparation machine (1) operable to dispense a beverage in a container (9), the fluid for preparing the beverage is heated by an electromagnetic induction continuous fluid heater (25) having a tubular body (27) defining a flow path for the fluid to be heated; the tubular body (27) has an end outlet section leading to a chamber (K) closed by plug-like bodies (37A, 37B) movable to allow access to the flow path; the plug-like (37A, 37B) are arranged outside the housing (2) or are removable and extractable through an opening (45) formed in the housing (2) to allow direct access to the flow path from the outside.

Description

[0001] Cross - reference to related applications

[0002] This patent application claims the priority of a European patent application with a filing date of June 19, 2020 and an application number of 20181250.0, and an Italian patent application with a filing date of September 18, 2020 and an application number of 102020000022039. The entire contents disclosed therein are incorporated herein by reference. Technical field

[0003] This application generally relates to the field of automatic beverage preparation machines, and particularly to a table - top or freestanding automatic beverage preparation machine equipped with an electromagnetic induction continuous fluid heater. Background art

[0004] As is well known, automatic beverage preparation machines are generally used to prepare beverages, especially hot beverages obtained by heating liquid products. The liquid products can be, for example, water for preparing coffee, tea, etc., or all types of milk, or milk - based mixtures for preparing hot milk, cappuccino, etc., or even gaseous, such as air or gaseous mixtures used as heating means for heating components for preparing beverages.

[0005] To this end, known automatic beverage preparation machines have fluid product heaters, which generally exist in the form of storage heaters (boilers, kettles) or continuous - flow or through - flow heaters.

[0006] Continuous fluid heaters operate according to two different technologies: resistive heating and electromagnetic induction heating. Resistive heating is common in the field, but electromagnetic induction heating is not as common in this field compared to the former.

[0007] In the first technology, a potential difference is applied across opposite ends of a heating element, which is directly or indirectly flowed through by the fluid to be heated. Then an electric current is generated in the heating element, and through the Joule effect, energy is dissipated in the form of heat to heat the fluid by conduction.

[0008] Two embodiments of the first technology are disclosed in patent EP 2 044 869 A1.

[0009] In the second technology, electromagnetic induction is used to heat the fluid to generate eddy currents in the heated pipe through which the fluid is to flow.

[0010] When the pipe is formed by a single - tube body made of a conductive material, the pipe can form an almost straight flow path. The eddy currents dissipate energy in the form of heat through the Joule effect, thereby heating the fluid flowing in the pipe.

[0011] Alternatively, the pipe can form a "twist", typically a helical flow path. In this case, the insert is disposed within the tubular body and together with the tubular body forms a helical flow path.

[0012] An electromagnetic induction continuous fluid heater having a helical flow path is disclosed in Italian Patent Application No. 102019000007166 and the corresponding international application No. PCT / IB2020 / 052950, both filed in the name of the present applicant.

[0013] In the above patent applications, the electromagnetic induction continuous fluid heater is used to heat water, and the electromagnetic induction is generated by an induction winding around the tubular body.

[0014] In another embodiment, the electromagnetic induction is generated by induction around the tubular body but at a certain distance from the tubular body.

[0015] In other embodiments, the electromagnetic induction is generated by associating the induction winding with the insert.

[0016] A different electromagnetic induction continuous fluid water heater in an automatic beverage preparation machine is disclosed in international applications WO 2015 / 063572 A1 and WO 2017 / 191529 A1. The water heater includes a metal heating pipe and an electric induction winding, the coils of the electric induction winding being wound around a spool made of an electrically insulating material and having an inner cavity accommodating the metal pipe. The metal pipe and the spool are at least partially separated by a gap within the cavity to allow separate maintenance of the metal pipe and the electric winding.

[0017] During experiments and tests, the applicant has experienced the special efficacy of the electromagnetic induction continuous fluid water heater, which is the subject of the applicant's Italian Patent Application No. 102019000007166 and international application No. PCT / IB2020 / 052950, for heating liquids containing fatty substances, in particular liquid milk for preparing milk-based beverages such as hot milk and caffe latte, and hot beverages brewed with high-pressure hot water such as coffee and tea beverages, which also contain liquid milk as well as hot or cold, foamed or unfoamed beverages such as caffe macchiato, cappuccino, etc.

[0018] In particular, the applicant has determined that this special efficiency stems from the water heater heating liquid milk without burning the fat contained therein, thus maintaining its sensory characteristics unchanged.

[0019] The Applicant has also verified how this water heater is able to effectively heat any type of liquid milk, among others, of natural origin, artificial origin, animal origin (cows, goats, sheep, donkeys, buffaloes, etc.), vegetable origin, raw, fresh, pasteurized, whole, partially or fully skimmed, UHT, lactose-free, and highly digestible, as well as any other type of milk.

[0020] The subject matter of Italian Patent Application No. IT 102020000014692 and the corresponding International Application No. PCT / IB2021 / 051201 is an electromagnetic induction continuous fluid heater for heating mixtures of liquid substances or fatty substances, both filed in the name of the present Applicant.

[0021] Finally, the Applicant has also determined the effectiveness of the water heater in its Italian Patent Application No. 102019000007166 and International Application No. PCT / IB2020 / 052950 for heating other types of fluids used in automatic beverage preparation machines, other types of fluids being, for example, gases or gas mixtures, in particular air for foaming milk, or air for heated beverages already produced, the temperature of which is unsatisfactory or different from that envisaged by the user.

[0022] The experiments carried out by the Applicant have to a large extent consisted in the following particularly beneficial effect of the electromagnetic induction continuous fluid heater: it allows the fluid to be heated in a short time.

[0023] Different fluid heaters in fluid foaming machines, in particular milk foaming machines, are disclosed in Patent US 2018 / 193807 A1 and WO 2017 / 216015. Summary of the Invention

[0024] The above-mentioned electromagnetic induction continuous fluid heater represents a generally functionally effective technical solution for heating liquids in automatic hot beverage preparation machines.

[0025] However, the Applicant has determined that effective heating requires careful daily cleaning of the pipes, the fluid in the pipes causing flow and regular replacement of certain components of the filter, but on the other hand, these cleaning / replacement operations are extremely difficult and require a relatively long intervention time.

[0026] This is because although the known heater can be opened or removed to allow access to the path of fluid flow, it is actually installed inside the housing of the automatic beverage preparation machine, in a difficult-to-reach position, and thus cleaning and / or replacing the housing parts of the same heater when necessary is subordinate to the disassembly of the housing parts. For the re-commissioning after maintenance / replacement, the reverse operation is of course necessary.

[0027] In some cases, the disassembly of the housing is not immediate and easy because, sometimes also for aesthetic reasons, the housing consists of half-housings or parts, even of complex geometries, which are joined together by "hidden" screws or bolts and thus cannot be accessed immediately.

[0028] In some cases, the maintenance of the heater even requires the automatic beverage preparation machine to be tilted or completely overturned, forcing the maintenance technician to operate under uncomfortable conditions and also to avoid liquid leakage along the heater opening or detaching the heater from the hydraulic or pneumatic circuit in the automatic beverage preparation machine.

[0029] Obviously, such an operation is both time-consuming and requires a relatively large support / manipulation space, which is usually not feasible in the area where the automatic beverage preparation machine is placed.

[0030] The object of the present invention is to provide an automatic beverage preparation machine with an electromagnetic induction continuous fluid heater, the design features of which allow the above problems to be solved in a simple and economical way, in particular allowing immediate access to the heater and making it easy to maintain.

[0031] According to claim 1, the present invention provides an automatic beverage preparation machine with an electromagnetic induction continuous fluid heater. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 An automatic beverage preparation machine according to the present invention and a preferred embodiment in a functional or beverage dispensing configuration are schematically shown in a perspective view.

[0033] Figure 2 With Figure 1 similarity, an automatic beverage preparation machine as shown in Figure 1 is shown in a maintenance configuration and some components are removed for clarity.

[0034] Figure 3 An automatic beverage preparation machine as shown in Figure 1 is shown in a cross-section.

[0035] Figure 4 An Figure 3 is shown in a cross-section along line IV-IV as shown in

[0036] Figure 5 An automatic beverage preparation machine as shown in Figure 2 is shown in a part of a partially disassembled maintenance configuration. DETAILED DESCRIPTION

[0037] The present invention will now be described in detail with reference to the accompanying drawings so that a person skilled in the art can obtain and use the present invention. Various modifications to the proposed embodiments will be immediately apparent to those skilled in the art, and the general principles disclosed herein can be applied to other embodiments and applications without thereby departing from the scope of protection of the present invention as defined in the appended claims. Therefore, the present invention should not be limited to the embodiments described and shown, but should be accorded the broadest scope of protection in accordance with the features described and claimed.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly used by a person of ordinary skill in the art related to the present invention. In case of conflict, this description, including the definitions provided, shall prevail. In addition, the examples provided are for illustrative purposes only and should not be considered limiting.

[0039] The terms used herein are only for describing the preferred embodiments and are not intended to limit the scope of the present invention.

[0040] Referring Figure 1 and Figure 2 , reference numeral 1 denotes an operable automatic beverage preparation machine for preparing general beverages, in particular hot beverages in which a fluid to be heated is heated starting from a predefined temperature, the predefined temperature being a function of the type / temperature of the beverage to be prepared and the physico-chemical and sensory characteristics of the liquid to be heated.

[0041] The following term "fluid" refers to any liquid product or any liquid mixture, such as water or milk, or any heatable gaseous substance or mixture, such as air. Air or an equivalent gas mixture is used for brewing beverages, such as tea, coffee, etc., or for foaming other substances, such as natural or artificial liquid milk, etc.

[0042] Still referring Figure 1 , the automatic beverage preparation machine 1 further comprises a housing 2 which in turn comprises a base wall 3, an upper wall 4, two side walls 5 and a front wall 6 facing the user in use. The walls 3 - 6 are firmly interconnected with each other.

[0043] In the described embodiment, the housing 2 has a front recess 7 ( Figure 3 ), the bottom of which is defined by a resting surface 8 of a cup 9 and the top of which is defined by a wall 8A ( Figure 3 ), into which the beverage is dispensed, and a beverage dispenser 10 projects from the wall 8A for dispensing the beverage into the cup 9.

[0044] Referring Figure 3 , the housing 2 houses a beverage preparation group 12 for preparing and dispensing beverages by heating a fluid, which in this case comprises a liquid (such as water or milk) and a gas (such as air or a gas mixture).

[0045] The beverage preparation assembly 12 includes a fluid inlet circuit 13, a heating device 14, and a fluid outlet circuit 15. Among them, the fluid inlet circuit 13 receives the fluid to be heated, the heating device 14 heats the received fluid, the heated fluid is heated in the fluid outlet circuit 15, and the fluid outlet circuit 15 has a fluid outlet connected to the fluid distribution nozzle 10.

[0046] The heating device 14 is an electromagnetic induction continuous fluid heater and has a fluid inlet 14A connected to the fluid outlet of the fluid inlet circuit 13 and a fluid outlet 14B connected to the fluid outlet circuit 15.

[0047] The fluid inlet circuit 13 includes a three-way selection valve 18, which has an inlet port fluidly connected to the water supply pipe 19, an inlet port fluidly connected to a liquid supply pipe 20 providing a liquid different from water (such as milk or cleaning liquid), and a fluid outlet 18A providing the selected liquid.

[0048] The fluid inlet circuit 13 further includes a proportional valve 21 operable to control the proportion of inlet air, a tubular T-joint 22 having an inlet fluidly connected to the outlets of valves 18 and 21, and an outlet fluidly connected to the inlet of the fluid outlet circuit 15 through a rotary pump 23 and a pressure sensor 24, which are known per se and thus not described in detail.

[0049] Refer to Figure 3 and in particular Figure 4 the heating device 14 includes two heaters 25, 26, which are respectively installed and fixedly coupled in the housing 2 and arranged in series with each other in the flow direction of the fluid provided by the fluid inlet circuit 13.

[0050] Conveniently but not necessarily, each heater 25, 26 is of the type described in Italian Patent Application No. 102020000014692 filed by the applicant on June 19, 2020, which is hereby incorporated by reference, and the disclosure of which regarding the necessary components is incorporated herein in its entirety.

[0051] Conveniently, the two heaters 25, 26 are of the same construction. Preferably, the two heaters 25, 26 are arranged side by side, as Figure 2 and Figure 4 shown and firmly connected to the housing 2.

[0052] In a variant not described, the two heaters 25, 26 are stacked.

[0053] In a variant, the two heaters 25, 26 are of different constructions.

[0054] Preferably, heaters 25 and 26 each include tubular bodies 27 and 28 having respective longitudinal axes 27A and 28A. Conveniently, axes 27A and 28A are parallel to each other and form an angle A with the stationary plane 8( Figure 3 ).

[0055] In the described preferred non-limiting embodiment, the tubular bodies 27 and 28 are substantially cylindrical and both axes A are straight.

[0056] Regardless of the geometry, each of the tubular bodies 27 and 28 is made of a conductive and magnetically permeable material so as to be inductively heatable by an electromagnetic induction field.

[0057] Heaters 25 and 26 also each include electrical windings 29 and 30 which, in the example, are coaxially wound about the tubular bodies 27 and 28 respectively with respect to axis A and are electrically drivable to generate an electromagnetic induction field.

[0058] Conveniently, the electrical windings 29 and 30 are independently controlled. Conveniently, winding 29 is controlled to heat the fluid to a temperature between 5 °C and 40 °C.

[0059] Winding 30 can controllably increase the temperature of the fluid provided by heater 25 to, for example, 70 °C.

[0060] In a variant, the electrical windings 29 and 30 are electrically connected in series and controlled together.

[0061] Referring again to Figure 3 , heater 25 is fluidly connected to the outlet of conduit 13 by a fluid connection means 31. In the example, the fluid connection means 31 is of the plug type and includes a fixed hollow collar 32 and a closing plug 33, the lower end portion of the tubular body 27 projecting into the hollow collar 32, the closing plug 33 defining a fluid passage and being fixed to the collar by a screw 34 so as to define the collar portion of a fluid-tight chamber K, the end of the tubular body 27 opening into the collar portion.

[0062] Referring to Figure 4 , heater 26 is fluidly connected to the inlet of the fluid outlet conduit 15 by a fluid connection means 43 having the same construction as the fluid connection means 31.

[0063] Referring to Figure 2 and Figure 4 , heaters 25 and 26 are interconnected by a fluid connection assembly 35 which includes a fluid connection means 37 associated with the tubular body 27, a fluid connection means 38 associated with the tubular body 28 and a tube 39 connecting the fluid connection means 37 and 38.

[0064] Conveniently, the fluid connection devices 37 and 38 are identical or similar in structure to the device 31 and respectively include their respective collars 37A, 38A and their respective plugs 37B, 38B, which define their respective fluid channels and are fixed to their respective collars 37A and 37B by screws 40 to define the same collar portions of their respective fluid sealing chambers K, where the free ends of the tubular bodies 27, 28 open and project into the same collar portions ( Figure 3 , Figure 4 and Figure 5 ).

[0065] Conveniently, each plug 37B, 38B stably carries a longitudinal insert 41, termed in the art as an "auger", which extends inside their respective tubular bodies 27, 28 and is configured to direct the fluid to be heated through a predetermined curved or twisted path.

[0066] In a variant not shown, the plugs 37B, 38B are devoid of the insert 41 and the fluid flows longitudinally along the axes 27A and 28A through the tubular bodies 27, 28.

[0067] Referring again to Figure 3 , Figure 4 and Figure 5 , the fluid connection assembly 35 extends beyond the fixed side wall 46 of the housing 2. The wall 46 is arranged adjacent to the upper wall 4, above the recess 7 and the fluid distribution nozzle 10, and is provided with a pair of openings 45 that put the interior of the housing into communication with the exterior.

[0068] In the example described, the tubular bodies 27, 28 extend from the wall 46 into the interior of the housing 2, while the collars 37A, 38A project from the wall 46.

[0069] In the example described, the collars 37A, 38A, the corresponding plugs 37B, 38B and the tube 39 are entirely arranged outside the housing 2. They are housed in the chamber 47 ( Figure 2 ).

[0070] The chamber 47 has a rear wall defined by the side wall 46 and is closed by a shaped hatch 48. Conveniently, the hatch 48 is hinged to the upper wall 4 to rotate about a hinge axis 49 between a closed position as shown in Figure 1 and an open position as shown in Figure 2 .

[0071] During beverage dispensing, the hatch 48 remains in the closed position, thus isolating the fluid connection assembly 35 from the exterior. On the other hand, when the heaters 25, 26 have to be maintained, the hatch 48 is moved to the open position and the screws 40 are removed, thus releasing the plugs 37B, 38B and the collars from the housing 2. At this time, whether the tube 39 is separated from at least one of the plugs 37B, 38B, as shown in Figure 5As shown, the plugs 37A, 38A are extracted along the associated insert 41, and when set, the interior of the tubular bodies 27, 28 is made visible ( Figure 5 ).

[0072] Under these conditions, an operator performing a cleaning operation can easily insert a pipe cleaner into the tubular bodies 27, 28 and perform cleaning. After cleaning, the plugs 37B, 38B are repositioned and screwed back, the tube 39 is reconnected, the hatch 48 is closed, and the automatic beverage preparation machine 1 is ready for operation again.

[0073] It can be clearly seen from the above that direct access to the tubular bodies 27, 28 from the outside is possible without disassembling parts of the housing 2 and keeping the automatic beverage preparation machine fixed in the same operating position. On the one hand, the cleaning and maintenance operations are greatly simplified, and on the other hand, the intervention time is greatly reduced. In particular, all descaling cleaning operations are facilitated.

[0074] In addition, compared to the operation of conventional machines, maintenance does not require operating space, and the environment around the automatic beverage preparation machine 1 is not contaminated by leakage of liquids or other substances, which may occur in some cases even when the machine is tilted.

[0075] The special design and control of the heaters 25, 26 allow precise and gradual control of the temperature of the fluid being heated to avoid temperature fluctuations, thus ensuring optimal processing regardless of the fluid being treated, especially in the presence of sensitive liquids.

[0076] It can be clearly seen from the above that the described automatic beverage preparation machine 1 can be modified and changed without exceeding the scope of protection defined by the independent claims.

[0077] In particular, the fluid connection devices 37, 38 can be different from those described. Specifically, the plugs 37B, 38B and the associated collars 37A, 38A can be connected to each other and to the housing 2 in ways other than those indicated by way of example, for example, by quick coupling and release devices such as bayonet or snap-on devices.

[0078] Moreover, the fluid connection devices 37, 38 are not entirely arranged outside the housing 2 but at least partially extend into the housing 2 through the opening 45 and are even arranged inside the housing 2. The opening 45 is configured to allow access to the housing 2 and allow the removal of the plugs 37B, 38B from the outside in order to provide direct access to the tubular bodies 27, 28 from the outside without disassembling the housing.

[0079] The opening 45 can be part of a single opening rather than a separate one.

[0080] Similarly, regardless of the embodiment, the fluid connection assembly 35 and the plugs 37B, 38B can be arranged in different areas of the housing 2 related to the dispensing nozzle 10, for example, arranged in the outer recess of the side wall 5, or even on the rear wall of the automatic beverage preparation machine 1.

[0081] In a preferred embodiment, the heaters 25, 26 can be arranged in such a position that the fluid connection device 43 can also enter from the outside through the access opening formed by the housing 2. Conveniently, the two access openings of the fluid connection devices 31, 43 are arranged opposite to each other, above and below the heaters 25, 26 respectively.

[0082] In addition, the chamber 47 can be closed by a hatch other than the example indication, or even an open chamber, in which case the hatch 48 is not required.

[0083] Finally, it can be clearly seen from the foregoing that the heating device 14 can only include one heater, for example, only the heater 25. In this case, the fluid outlet circuit 15 extends from the fluid connection device 37.

Claims

1. An automatic beverage preparation machine (1) for operably preparing and dispensing a beverage into a container (9); the automatic beverage preparation machine (1) includes a housing (2), a support for the container (9), and a beverage preparation assembly (14) for operably preparing and dispensing a beverage into the container (9); the beverage preparation assembly (14) includes: A fluid supply circuit (13) for operably supplying a fluid to be heated for beverage preparation; A fluid outlet circuit (15) for supplying the heated fluid; And At least one electromagnetic induction continuous fluid heater (25) fluidly connected to the fluid supply circuit (13) and the fluid outlet circuit (15); The electromagnetic induction continuous fluid heater (25) includes: A tubular body (27) that is fluidly connected to the fluid supply circuit (13) and the fluid outlet circuit (15) and defines a path for the fluid to be heated to flow; and Fluid connection means (37) provided between the end of the tubular body (27) and the fluid outlet circuit (15) and defining a chamber (K), the end of the tubular body (27) opening into the chamber (K); The fluid connection means (37) includes: plug-like bodies (37A, 37B) for closing the chamber (K), and the fluid connection means (37) is configured to define a fluid passage communicating with the chamber (K); Releaseable connection means (40) for holding the plug-like bodies (37A, 37B); and An electric winding (29) for electrically driving to generate an electromagnetic induction field to heat the fluid flowing in the tubular body (27); It is characterized in that the housing (2) has an opening (45) that communicates the interior of the housing (2) with the exterior; the plug-like bodies (37A, 37B) are provided outside the housing (2) or can be extracted from the housing (2) through the opening (45); and the releaseable connection means (40) can be moved by an action from outside the housing (2).

2. The automatic beverage preparation machine (1) according to claim 1, wherein, The tubular body (27) has a longitudinal axis (27A) passing through the plug-like bodies (37A, 37B), and the longitudinal axis (27A) passes through the opening (45).

3. The automatic beverage preparation machine (1) according to claim 1 or 2, wherein, The automatic beverage preparation machine (1) further includes a hatch (48) coupled to the housing (2) and movable between a closed position and an open position, wherein in the closed position the plug-like bodies (37A, 37B) are prevented from entering, and in the open position the plug-like bodies (37A, 37B) can be disassembled and removed and direct access to the fluid passage is allowed.

4. The automatic beverage preparation machine (1) according to claim 1, wherein, The opening (45) is formed in a wall of the housing (2) disposed above the support.

5. An automatic beverage preparation machine (1) according to claim 1 or 2, wherein, The automatic beverage preparation machine (1) further includes a dispensing nozzle (10) provided outside the housing (2) for dispensing a beverage into the container (9); an opening (55) is formed above the dispensing nozzle (10).

6. The automatic beverage preparation machine (1) according to claim 2, wherein, The support member includes a stationary surface (8) for placing the container (9), and the longitudinal axis (27A) is inclined with respect to the stationary surface (8).

7. An automatic beverage preparation machine (1) according to claim 1, wherein, The automatic beverage preparation machine (1) further includes at least one other electromagnetic induction continuous fluid heater (26), which is connected in series to the electromagnetic induction continuous fluid heater (25); the other electromagnetic induction continuous fluid heater (25) includes at least one other tubular body (28), and the other tubular body (28) also defines another path for the fluid to be heated to flow; other fluid connection devices (38, 39) are arranged between the two electromagnetic induction continuous fluid heaters; the other fluid connection devices (38, 39) define other chambers (K), the end segments of the other tubular body (28) open into the other chambers (K), and the other chambers (K) include other plug-shaped bodies (38A, 38B) to close the chambers (K) and are configured to define other fluid channels communicating with the other chambers (K); other releasable connection devices (40) are provided to enable the other plug-shaped bodies (38A, 38B) to be removed; other electrically drivable electric windings (30) are provided to generate an electromagnetic induction field to heat the fluid flowing in the other tubular body (28); the other plug-shaped bodies (38A, 38B) are provided outside the housing (2) or can be extracted from the housing (2) through other openings (45) formed in the housing (2); the releasable connection devices (40) can be moved by an action from outside the housing (2).

8. The automatic beverage preparation machine (1) according to claim 7, wherein, The fluid connection device includes a fluid connection pipe to connect the chamber (K) to the other chamber (K); the pipe extends at least partially outside the housing (2) and is configured to be separated from at least one of the chambers (K).

9. The automatic beverage preparation machine (1) according to claim 7, wherein, At least one of the tubular bodies (27, 28) houses a guiding member (41) to guide the fluid flow along a curved path during heating; the guiding member (41) is firmly connected to the associated plug-shaped body and can be extracted through the associated opening (45).

10. An automatic beverage preparation machine (1) according to any one of claims 7 to 9, wherein, The plug-shaped bodies (37A, 37B) and the other plug-shaped bodies (38A, 38B) are arranged side by side.

11. The automatic beverage preparation machine (1) according to claim 1, wherein, The electric windings (29, 30) are operationally independent and selectively electrically drivable to heat the fluid flowing along their respective paths at different temperatures.

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