A liquid foodstuff production plant including a system for recovering thermal energy

Abstract

A liquid foodstuff production plant comprising: a filling machine configured to fill containers with liquid foodstuff; a thermal treatment tunnel machine; and a conveyor configured to move the filled containers through the tunnel machine, the tunnel machine being configured to apply liquid to the moved filled containers so as to cause a temperature change of the liquid foodstuff. The production plant further including a system comprising: a heat pump; a conduit passing through the heat pump to allow a flow of liquid foodstuff through the heat pump; and a circuit configured to collect at least some of the liquid applied to the filled containers and to recirculate the liquid through the tunnel machine, passing through the heat pump to allow a flow of the collected liquid through the heat pump. The heat pump is configured to exchange thermal energy between the liquid foodstuff and the collected liquid flowing therethrough.

Description

[0001] “A LIQUID FOODSTUFF PRODUCTION PLANT INCLUDING A SYSTEM FOR RECOVERING THERMAL ENERGY”

[0002] Field

[0003] The present invention relates to liquid foodstuff production plant including a system for recovering thermal energy in the production plant.

[0004] Background

[0005] In liquid foodstuff production plants, when the liquid foodstuff is to be cooled before being poured into containers, an intermediate heat exchanger and related utilities are involved to cool the liquid foodstuff (typically using propylene glycol as a refrigerant to reduce the temperature of the liquid foodstuff). Similarly, when the liquid foodstuff is to be heated during its preparation process, an intermediate heat exchanger and related utilities are involved to heat the liquid foodstuff using steam or hot water (in case of hot water, one or more stratification tanks can be used to store the water).

[0006] The use of these intermediate heat exchangers and related utilities, managed at the plant level, helps to control the risk of contamination of the liquid foodstuff. In practice, the heat exchangers work as an intermediate barrier between the liquid foodstuff under process and a source of thermal energy (external to the foodstuff preparation and filling line). Furthermore, the steam / hot water and propylene glycol are not harmful to the liquid foodstuff under treatment, thus providing additional safety in case of leakage during the heating / cooling process.

[0007] Any known attempt to heat / cool the liquid foodstuff via a direct contact with a heat pump (for example a double walled chiller) results in a reduced efficiency or works only with a very high temperature difference.

[0008] Summary

[0009] According to an aspect of the present disclosure, there is provided a liquid foodstuff production plant according to claim 1.

[0010] In embodiments, a heat pump is used to exchange thermal energy between liquid foodstuff (flowing through the heat pump before being dispensed into containers) and liquid applied to containers already filled with liquid foodstuff and moved through a thermal treatment tunnel machine (the applied liquid flowing through the heat pump along a circuit for collecting and recirculating the applied liquid through the tunnel machine), thereby warming one of the liquid foodstuff and the collected liquid and cooling the other of the liquid foodstuff and the collected liquid.

[0011] In this way, the heat pump is advantageously used to directly exchange thermal energy between the liquid foodstuff under preparation and the tunnel machine, thus avoiding (or at least limiting) the use of intermediate heat exchangers and related utilities and allowing the recovery of thermal energy directly within the foodstuff preparation and filling line.

[0012] For example, in some embodiments the prepared liquid foodstuff is with gas (e.g., beer or soft drinks) and cooled at a temperature suitable for avoiding foam formation during the filling process (cold filling). In these embodiments, the heat pump is used to directly remove thermal energy from the liquid foodstuff under preparation (flowing through the evaporator of the heat pump before / after addition / formation of gas - and / or before / after being mixed with substances, if required) and convey the removed thermal energy to the liquid collected from a tunnel warmer or a tunnel pasteurizer (flowing through the condenser of the heat pump). The warmed collected liquid is recirculated through the tunnel warmer or tunnel pasteurizer, thus directly recovering the thermal energy removed from the liquid foodstuff into the tunnel warmer or tunnel pasteurizer.

[0013] In some other embodiments, the prepared liquid foodstuff is without gas (e.g., a sport drink) and as such, after undergoing a heating process (e.g., flash pasteurization), it can be dispensed into containers at a temperature greater than ambient temperature (hot filling), thus requiring the filled containers be then cooled using a tunnel cooler. In these embodiments, the heat pump is used to directly remove thermal energy from liquid collected from the tunnel cooler (flowing through the evaporator of the heat pump before being recirculated through the tunnel cooler) and convey the removed thermal energy to liquid foodstuff (flowing through the condenser of the heat pump before undergoing the required heating process). In this way, the cooled liquid can be re-used in the tunnel cooler, while its removed thermal energy is directly recovered by pre-heating the liquid foodstuff before undergoing the heating process (thus saving energy required in the heating process).

[0014] It is important to note that the use of the heat pump to directly exchange thermal energy between liquid foodstuff and liquid collected from a tunnel machine not only avoids the costs involved in the use of intermediate heat exchangers (e.g., installation and maintenance costs) to heat / cold the liquid foodstuff, but also reduces the temperature gap between the fluids involved in the thermal exchange (thus resulting in an increased efficiency).

[0015] In this regard, it will be appreciated that since in the tunnel machine liquid is applied to filled containers moved therethrough in order to gradually change the temperature of the contained liquid foodstuff, the temperature of applied liquid collected from the tunnel machine and the temperature of the liquid foodstuff before the filling process can be close enough so as to result in a coefficient of performance, cop, for the operating heat pump at least greater than 2.5 (for example up to 6.5 in the embodiments where heat is exchanged between the liquid foodstuff and liquid collected from a tunnel warmer or tunnel cooler, or up to 5 in some embodiments where heat is exchanged between the liquid foodstuff and liquid collected from a tunnel pasteurizer).

[0016] Furthermore, it will be appreciated that the amount of liquid foodstuff flowing through the heat pump and the amount of liquid foodstuff within containers passing through the tunnel machine is the substantially the same (with a short delay in time required to provide the filled containers to the tunnel machine), thus the energy recovered from the liquid foodstuff is employed substantially in real time.

[0017] Brief Description of the Drawings

[0018] Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

[0019] Figure 1 schematically illustrates a system for recovering thermal energy in a liquid foodstuff production plant, including a heat pump to directly exchange thermal energy between liquid foodstuff under preparation and a 3 -zones tunnel warmer;

[0020] Figure 2 schematically illustrates the components of the heat pump illustrated in Figure 1 and their interaction with the liquid foodstuff and the 3 -zones tunnel warmer;

[0021] Figure 3 is a lateral view of the heat pump illustrated in Figures 1 and 2.

[0022] Figure 4 illustrates an example of a thermal cycle of a liquid foodstuff flowing through the heat pump and the 3-zones tunnel warmer illustrated in Figure 1.

[0023] Figure 5 illustrates the system of Figure 1, further including a heater between the heat pump and the tunnel warmer.

[0024] Figure 6 illustrates the system of Figure 1, modified to include a buffer stratification tank; Figure 7 schematically illustrates a first embodiment of a liquid foodstuff production plant including a system for recovering thermal energy, the system including a heat pump to directly exchange thermal energy between liquid foodstuff under preparation and a 9-zones tunnel pasteurizer.

[0025] Figure 8 illustrates an example of a thermal cycle of a liquid foodstuff flowing through the heat pump and the 9-zones pasteurizer illustrated in Figure 7. Figure 9 schematically illustrates a system for recovering thermal energy in a liquid foodstuff production plant, including a heat pump to directly exchange thermal energy between liquid foodstuff under preparation and a 4-zones tunnel cooler.

[0026] Figure 10 schematically illustrates the components of the heat pump illustrated in Figure 9 and their interaction with the liquid foodstuff and the 4-zone tunnel cooler;

[0027] Figure 11 illustrates an example of a thermal cycle of a liquid foodstuff flowing through the heat pump and the 4-zones tunnel cooler illustrated in Figure 9.

[0028] Figure 12 illustrates the system of Figure 9, modified to include a buffer stratification tank. Figure 13 schematically illustrates a second embodiment of a liquid foodstuff production plant including a system for recovering thermal energy, the system including a heat pump to directly exchange thermal energy between liquid foodstuff under preparation and a 9-zones tunnel pasteurizer.

[0029] Description of the Embodiments

[0030] Before disclosing embodiments of the invention with reference to the Figures 1-13, it is to be noted that the in the present disclosure the term “liquid foodstuff’ encompasses any food in liquid or semi-liquid form (that can be ingested by humans or animals or that can be absorbed by plants), with or without gas, and with a viscosity allowing the flow of the foodstuff through a conduit, such as (but not limited to) alcoholic drinks (e.g., beer, spirits, wine, et cetera), soft drinks (e.g., cola, soda, et cetera), non-carbonated drinks (such as sport drinks, tea, fruit-flavoured drinks, et cetera), milk, juices, water, sauces, soups, molasses, syrups, oils, and vinegars, et cetera.

[0031] It is to be further noted that same / similar elements / components of the disclosed embodiments are indicated through Figures 1-13 with similar reference numerals.

[0032] Referring now to Figure 1, there is illustrated a system 10 for recovering thermal energy in a carbonated liquid foodstuff production plant.

[0033] In particular, a filling machine 11 is used, along a foodstuff process line, to fill containers (such as bottles, cans, or packs) with prepared carbonated liquid foodstuff. The prepared liquid foodstuff can be carbonated as an intrinsic result of its preparation phase (e.g., fermentation for producing beer) or as a result of external gas introduction into the liquid foodstuff under preparation (e.g., to obtain soft drinks, like a cola or soda drink). The preparation of the carbonated liquid foodstuff can also optionally involve mixing the liquid foodstuff within one or more substances (e.g., colourant or flavour substances), before or after the liquid foodstuff is carbonated. In order to avoid foam formation, the ambient temperature of the liquid foodstuff is reduced before the prepared liquid foodstuff undergoes the carbonating process and then filling process (cold filling).

[0034] After the cold filling, one or more auxiliary conveyors (not shown in Figure 1) are used to move the filled containers until they reach a tunnel warmer 100 employed in the foodstuff process line. The tunnel warmer 100 comprises a conveyor 2 to move the filled containers through its zones. In particular, the tunnel warmer 100 comprises three zones 101, 102, 103 with respective sprayers 104, 105, 106 arranged at top portions of the zones 101, 102, 103 and configured to spray water, at respective set temperatures, on the filled containers moved by the conveyor 2 through the three tunnel zones (starting from the zone 101).

[0035] The set temperature of the water sprayed in the second zone 102 is greater than the set temperature of the water sprayed in the first zone 101 and lower than the set temperature of the water sprayed in the third zone 103, so as to cause a controlled gradual increase of the temperature of the liquid foodstuff within the containers moved through the zones 101-103. For example, the tunnel warmer 100 can be used to cause an increase of temperature of the liquid foodstuff such as to reach a temperature above a dew point (thus drying condensation that can be formed on the containers during the cold filling).

[0036] The bottom portions of the tunnel zones 101-102 are in communication via an opening 107 and the bottom portions of the tunnel zones 102-103 are in communication via an opening 108, so as to allow a limited flow of sprayed water between adjacent tunnel zones (such that to balance the level of sprayed water at the bottom portions of the zones). In particular, some of the water sprayed in the first zone 101 can flow, through the opening 107, into the bottom portion of the second zone 102, and some of the water sprayed in the second zone 102 can flow, through the opening 108, into the bottom portion of the third zone 103.

[0037] In this and the other disclosed embodiments, it is assumed that the production plant operates (under normal conditions) according to a continuous line process, whereby prepared liquid foodstuff and empty containers are continuously provided to the filling machine 11, the filling machine 11 continuously fills received empty containers with received liquid foodstuff, and the filled containers are continuously provided to the employed thermal treatment tunnel machine (the tunnel warmer 100 in Figure 1), with only a short time delay required to cover the distance between the filling machine 11 and the tunnel machine.

[0038] In order to cool the liquid foodstuff before reaching the filling machine 11, the system 10 comprises a fluid-to-fluid heat pump 20 including an evaporator 21 and a condenser 22. The system 10 further comprises: a conduit 23 passing through the evaporator 21 (to allow a continuous flow of liquid foodstuff through the evaporator 21 of the heat pump 20); and a circuit configured to collect sprayed water from the bottom of the last tunnel zone 103 and to recirculate the collected water through the tunnel zones 101-103, passing through the condenser 22 of the heat pump 20.

[0039] In particular, the circuit comprises: a conduit 25 connected to an opening 26 defined at the bottom of the last tunnel zone 103 and passing through the condenser 22 of the heat pump 20; and a pump 27 positioned along the conduit 25 and configured to pump sprayed water drained from the opening 26 through the conduit 25, thus causing a continuous flow of the drained sprayed water through the condenser 22 (before being recirculated through the zones 101-103).

[0040] The configuration of the heat pump 20 to cause a thermal transfer from the liquid foodstuff to the drained sprayed water flowing respectively through the evaporator 21 and condenser 22 is explained with reference now to Figure 2.

[0041] In particular, the heat pump 20 comprises an internal circuit 30 allowing a continuous circulation of a refrigerant (e.g., propylene glycol) between the evaporator 21 and the condenser 22. A compressor 33 (connected to an electrical motor 34 controlled by a variable frequency driver 35, VFD) and an expansion valve 36 are provided, along opposite sides of the circuit 30, between the evaporator 21 and the condenser 22.

[0042] In operation, the refrigerant flowing (in a liquid form at a cold temperature) through the evaporator 21 absorbs heat from the liquid foodstuff concurrently flowing through the evaporator 21, thereby cooling the liquid foodstuff to a temperature suitable for cold filling. Then, the refrigerant flows through the compressor 33 that increases the pressure (and temperature) of the refrigerant so as to cause a change of its state from liquid to gas. The refrigerant in the gas form flows through the condenser 22, thereby transferring the heat removed from the liquid foodstuff to the water drained from the last tunnel zone 103 that is concurrently flowing through the condenser 22. Then, the cooled refrigerant flows through the expansion valve 36 that causes a drop of pressure (and temperature) of the refrigerant, thus changing its state from gas back to liquid. The liquid (and cooled) refrigerant is then recirculated through the evaporator 21, restarting the thermal cycle of the heat pump 20. It will be appreciated that the evaporator 21 and the condenser 22 allow a direct thermal exchange between the liquid foodstuff and the water drained from the last tunnel zone 103 without physical contact between these fluids, thus limiting a foodstuff contamination risk (in compliance with the special needs, such as hygiene, purity, and potability, of the liquid foodstuff under process).

[0043] With reference now to Figure 3, in some embodiments the evaporator 21 and the condenser 22 are inclined in order to further enhance safety of the foodstuff under processing. In particular, the inclination of the evaporator 21 facilitates a full drain of foodstuff out from the heat pump 20 (thus avoiding foodstuff stagnation that may result in contamination due to microbiological formations). Similarly, the inclination of the condenser 22 facilitates a full drain of refrigerant out from the condenser 22 (thus avoiding refrigerant stagnation).

[0044] In some embodiments a system can also be provided to stop the flow of the foodstuff towards the evaporator 21 and / or the flow of the water drained from the tunnel zone 103 towards the condenser 22 in case of detecting a pressure (or other parameter) difference between the refrigerant fluid circulating in the heat pump 20 and at least one of the liquid foodstuff entering the evaporator 21 and the drained water entering the condenser 21 exceeding a defined threshold.

[0045] At least one of the following precautions may also be implemented to improve safety of the liquid foodstuff: using an edible fluid as refrigerant, using in the evaporator 21 a surface in contact with the liquid foodstuff having roughness less than Ra < 0.8 pm (to avoid retention of dirt), and using double ferrule and closure clamps and / or front flanges and / or food grade gasket connections for the evaporator 21 and / or condenser 22.

[0046] With reference back to Figure 1, it is assumed for example that the heat pump 20 is used to cool liquid foodstuff substantially ready to be poured within the containers (except for the required decrease of temperature operated by the heat pump 20). This means that the liquid foodstuff entering the evaporator 21 is already carbonated (and mixed with one or more substances, if required). Thus, the heat pump 20 can be installed into or in proximity to the production plant hall including the filling machine 11, and the conduit 23 extends, after passing through the evaporator 21, until reaching the filling machine 11. Thus, the conduit 23 allows a direct flow of the prepared and cooled liquid foodstuff to the filling machine 11 (as illustrated in Figure 1). Alternatively, the conduit 23 can be connected to one or more further conduits allowing flow therethrough of the cooled foodstuff liquid until reaching the filling machine 11.

[0047] The warmed water drained from the last tunnel zone 103 is distributed, after flowing out from the condenser 22, to the tunnel zones 101-103 based on the energy demand to maintain the set temperatures of the water sprayed by the sprayers 104-106. In particular, the circuit used to recirculate the warmed sprayed water flowing out from the condenser 22 includes three conduits 51, 52. 53 connecting, respectively, openings 44, 45, 46 defined at the bottom of the tunnel zones 101, 102, 103 to the respective sprayers 104, 105, 106 of the zones 101, 102, 103. The circuit further comprises three pumps 41, 42, 43 positioned along the conduits 51, 52, 53, respectively, and configured to pump, through the openings 44-46 and the respective conduits 51-53, some of the sprayed water at the bottom of the respective tunnel zones 101-103 to the sprayers 104-106.

[0048] In this regard, it is to be noted that the sprayed water drained through the openings 44-46 have been in contact with filled containers moved by the conveyor 2, thus causing a decrease in temperature of the sprayed water of one or a few degrees Celsius.

[0049] Thus, in order to maintain the set temperatures of the water sprayed in the zones 101-103, the circuit further includes three conduits 54, 55 and 56 connecting the conduit 25 to the conduits 51, 52 and 53, respectively, and three temperature control valves, TCVs, 47, 48, 49 positioned along the conduits 54, 55 and 56, respectively.

[0050] The TCVs 47-49 are configured to be actuated to mix an amount of warmed water flowing out, through the conduit 25, from the condenser 22 with drained sprayed water flowing, through the conduits 51-53, towards the pumps 41-43, to maintain the set temperature of the water sprayed by the sprayers 104-106.

[0051] For example, each conduit 51, 52, 53 can be associated with a respective controller (e.g., a PID controller, not illustrated in Figure 1) connected to a respective one of the TCVs 47-49 and in communication with a temperature sensor (e.g., a probe) for sensing the temperature of the sprayed water drained from the openings 44-46. Based on the sensed temperature, each controller can control the aperture of the respective TCV 47, 48, 49 to modulate the amount of warmed water flowing therethrough, in such a way as the resulting mixed water provided to the respective sprayers 104, 105, 106 is at the required set temperature. Alternatively, a single controller can be employed to actuate the three TCVs 47, 48, 49, in communication with each of the temperature sensors associated with the conduits 51, 52, 53 (or thermostatic TCVs can be used instead of actuated TCVs).

[0052] An exemplary operation of the system 10 is disclosed with reference now to the Figure 4, illustrating for example the thermal cycle of a cola drink undergoing, during the continuous foodstuff line process, first the cooling process operated by the heat pump 20 and then (after being poured into containers) the warming process operated by the tunnel warmer 100. As illustrated in portion 60 of Figure 4, the values of the set temperatures of the water sprayed by the sprayers 104, 105, 106 are, respectively, 29 °C, 34 °C and 38 °C, suitable for causing an increase of temperature of the cold cola within the containers from about 12°C to about 30 °C.

[0053] Starting from the third tunnel zone 103, the sprayers 106 spray water at the set temperature of 38 °C on filled containers that are moved through the zone 103 by the conveyor 2. The sprayed water reaches the bottom portion of the zone 103 with a decreased temperature of about 37 °C (due to the contact with the containers filled with cola). Some of this sprayed water is drained from the opening 26 and pumped through the conduit 25 so as to reach and flow through the condenser 22.

[0054] As illustrated in portion 61 of Figure 4, the thermal exchange operated by the heat pump 20 results in a temperature decrease of the cola from the ambient temperature of about 25 °C to about 12 °C, and in a corresponding temperature increase of the drained sprayed water from 37 °C to about 42 °C (the difference between the amounts of temperature decrease and increase of the cola and the drained sprayed water depending on the flow rate difference between the cola and drained sprayed water).

[0055] It is to be appreciated that due to the proximity between the temperature values of the sprayed water flowing out from the condenser 22 and the cola flowing into the evaporator 21, the cop of the pump 20 is particularly high (about 6.25). This because the cop of a heat pump is inversely proportional to the electrical power required by the compressor 33, and the less the gap between the input temperature of the liquid providing heat energy and the output temperature of the liquid receiving the heat energy the less work is required by the compressor 33.

[0056] It is to be further appreciated that by operating a heat pump in cooperation with a tunnel warmer to cool liquid foodstuff, as per the principles disclosed with reference to the exemplary embodiment of Figure 1 (and considering different liquid foodstuff and / or sprayed liquid temperatures than the temperatures illustrated for example in Figure 4), the difference in temperature between liquid foodstuff flowing into the evaporator 21 and warmed sprayed water flowing out from the condenser 22 is generally lower than 30 °C (resulting in a cop greater than about 4.5), and can range for example down to 15 °C (resulting in a cop ranging up to about 6.5).

[0057] With reference now to portion 62 of Figure 4, a certain time is needed for the cooled cola to continue its flow until reaching the filling machine 11 and, once bottled / canned, to reach the tunnel warmer 100. In the meantime: the TCV 47 is controlled to mix sprayed water drained through the opening 44 (at a temperature of about 28 °C after being in contact with filled containers moved through the first zone 101) with a first amount of the warmed water (at 42 °C) flowing through the conduit 25, required to obtain mixed water at the set temperature of 29 °C (that is provided, by the pump 41, to the sprayers 104); the TCV 48 is controlled to mix sprayed water drained through the opening 45 (including: water sprayed by the sprayers 104, flowing into the bottom potion of the second zone 102 via the opening 107, at a temperature of about 28 °C; and some of the water sprayed by the sprayers 105, at a temperature of about 33 °C after being in contact with filled containers moved through the second zone 102) with a second amount of the warmed water (at 42 °C) still flowing through the conduit 25, required to obtain mixed water at the set temperature of 34 °C (that is provided, by the pump 42, to the sprayers 105); the TCV 49 is controlled to mix sprayed water drained through the opening 46 (including: water sprayed by the sprayers 105, flowing into the bottom potion of the third zone 103 via the opening 108, at a temperature of about 33 °C; and some of the water sprayed by the sprayers 106 of the third zone 102, at a temperature of about 37 °C after being in contact with filled containers moved through the third zone 103) with a third amount of the warmed water (at 42 °C) still flowing through the conduit 25, required to obtain mixed water at the set temperature of 38 °C (that is provided, by the pump 43, to the sprayers 106). With reference now to Figure 5, an embodiment is illustrated where the system 10 is further provided with a heater 70 connected to a portion of the conduit 25 between the condenser 22 and the intersection with the conduit 54. In particular, the heater 70 includes a conduit 71 to allow a flow therethrough of steam (or hot water). The conduit 25 passes through the heater 70, thereby allowing transfer of thermal energy from the steam (or hot water) flowing through the conduit 71 to the sprayed liquid flowing through the conduit 25 before being recirculated through the tunnel zones 101-103. The cooled steam (or hot water) is provided back to a condenser connected to an external source of heat, and then recirculated through the heater 70.

[0058] In some embodiments, the heater 70 can be used to heat the sprayed water to be recirculated through the tunnel zones 101-103 instead of the heat pump 20, at the start-up of the line process (when the heat pump 20 is still not operating) and / or in case of emergency (when the heat-pump 20 stops operating). In alternative embodiments, the heater 70 may be used in cooperation with the heat pump 20 so as to further heat the warmed sprayed water flowing out from the condenser 22, before being recirculated through the tunnel zones 101-103. Furthermore, in some embodiments where the heat pump 20 is added, as a retrofit solution, to a pre-existing foodstuff process line, the heater 70 can be a heater already present in the production plant (advantageously reused to work in alternative to or in cooperation with the newly installed heat pump 20).

[0059] With reference now to Figure 6, the system 10 of Figure 1 is modified to include a stratification tank 80 (initially filled with water at atmospheric temperature) that works as a buffer for storing warmed water provided by the heat pump 20 that can be recirculated, when required, through the zones 101-103 of the tunnel warmer 100.

[0060] In particular, a bottom portion of the tank 80 is connected, via a valve 81, to a first portion 25a of the conduit 25 between the opening 26 and the condenser 22 (before the pump 27). A second portion 25b of the conduit 25 extends from the output of the condenser 22 to an opening 82 defined at a first side of the top portion of the tank 80. A conduit 28 extends from an opening 83, defined at a second side of the top portion of the tank 80, and is connected to the conduits 54, 55 and 46. A pump 84 is disposed along the conduit 28 close to the top portion of the tank 80 (before the intersection with the conduit 54).

[0061] Under normal conditions (where liquid foodstuff is continuously flowing through the evaporator 21 and containers filled with liquid foodstuff are continuously moved through the tunnel zones 101-103), the valve 81 is operated to allow the flow of the sprayed water drained from the last tunnel zone 103 to the condenser 22 (while preventing a flow towards the bottom portion of the tank 80), and the pump 84 causes a flow of sprayed water warmed by the heat pump 20 into the top portion of the tank 80, and from the top portion of the tank 80 towards the conduits 54-56.

[0062] When there are first time periods during which no containers filled with liquid foodstuff are available to be thermally processed by the tunnel warmer 100 but liquid foodstuff is flowing through the evaporator 21 (e.g., at the start of operation of the foodstuff process line), the warmed sprayed water flowing through the condenser 22 can be advantageously stored in the top portion of the tank 80.

[0063] When there are second time periods during which no liquid foodstuff is flowing through the evaporator 21 but containers filled with liquid foodstuff are available to be thermally processed by the tunnel warmer 100 (e.g., close to the end of operation of the foodstuff process line), the valve 81 can be operated to divert the flow of sprayed water drained from the last tunnel zone 103 towards the bottom portion of the tank 80, while the warmed water stored in the top portion of the tank 80 during the first periods can be pumped through the conduit 28 to be distributed, according the amount required to maintain the set temperatures, to the sprayers 104-106. In this way, the tank 80 can recirculate warmed sprayed water through the tunnel zones 101-103 (at least for a limited time depending on the amount of stored warmed water and the tank volume).

[0064] Referring now to Figure 7, there is illustrated a system 150 for recovering thermal energy in a carbonated liquid foodstuff production plant, substantially differing from the system 10 illustrated in Figure 1 in that the heat pump 20 is used to cool the liquid foodstuff using sprayed water drained from a zone of a tunnel pasteurizer 200 instead of a tunnel warmer. In particular, the tunnel pasteurizer 200 comprises nine zones 201-209 having respective sprayers 211-219 arranged at top portions of the zones 201-209 and configured to spray water, at respective set temperatures, on filled containers moved by the conveyor 2 through the zones (starting from the zone 201).

[0065] The set temperatures of the water sprayed in the lateral zones 201-203 are suitable for causing a controlled gradual increase of the temperature of the liquid foodstuff within the moved containers. The set temperatures of the water sprayed in the central zones 204-206 are suitable for causing a further increase of the liquid foodstuff temperature to reach and maintain a pasteurization temperature. The set temperatures of the water sprayed in the lateral zones 207-209 are suitable to cause a controlled gradual decreased of the temperature of the liquid foodstuff within the moved containers.

[0066] The bottom portions of the tunnel zones 201-209 are in communication via openings 220- 227, so as to allow a limited flow of sprayed water between tunnel zones (to balance the level of sprayed water at the bottom portions of the tunnel zones). In particular: some of the water sprayed in the zone 209 can flow, through the opening 227, into the bottom portion of the zone 208, and some of the water sprayed in the zone 208 can flow, through the opening 226, into the bottom portion of the zone 207; and some of the water sprayed in the zone 206 can flow, through the opening 224, into the bottom portion of the zone 205, and some of the water sprayed in the zone 205 can flow, through the opening 223, into the bottom portion of the zone 204.

[0067] A flow of sprayed water between the zones 206 and 207, through the opening 225, can be controlled via a valve (not illustrated in Figure 7, that can allow flow of water only in response to a certain reached level of sprayed water at the bottom portion of the zone 207). The system 150 includes a circuit configured to collect sprayed water from an opening 228 defined at the bottom of the zone 207 and to recirculate the collected water through the lateral tunnel zones 201-203 and 207-209, passing through the condenser 22 of the heat pump 20.

[0068] In particular, the circuit comprises: a conduit 230 having a first end connected to the opening 228 and a second end connected to a first opening of an intermediate atmospheric tank 231 (warm tank 231) for storing the drained sprayed water; a conduit 232 connected to a second opening of the warm tank 231 and passing through the condenser 22; a pump 233 positioned along the conduit 232, between the warm tank 231 and the condenser 22, and configured to pump sprayed water stored in the warm tank 231 through the conduit 232, thus causing a continuous flow of sprayed water from the bottom portion of the tunnel zone 207 into the warm tank 231 , and from the warm tank 231 through the condenser 22.

[0069] The heat pump 20 causes a transfer of thermal energy from the liquid foodstuff flowing through the evaporator 21 (along the conduit 23) to the sprayed water flowing through the condenser 22, thereby cooling the liquid foodstuff (at temperature suitable for operating cold filling) and warming the sprayed water.

[0070] After flowing out from the condenser 22, the warmed water is distributed to the lateral tunnel zones 201-203 and 207-209.

[0071] In particular, the circuit to recirculate the warmed sprayed water includes: a conduit 241 connecting an opening 244 defined at the bottom of the zone 209 to the sprayers 211 of the zone 201; a conduit 242 connecting an opening 245 defined at the bottom of the zone 208 to the sprayers 212 of the zone 202; and a conduit 243 connecting an opening 246 defined at the bottom of the zone 207 to the sprayers 213 of the zone 203.

[0072] The circuit further includes: three pumps 261, 262, 263 disposed, respectively, along the conduits 241, 242, 243, and configured to pump, through the openings 244-246 and the respective conduits 241-243, some of the sprayed water present at the bottom of the tunnel zones 207-209 to the sprayers 211-213 of the tunnel zones 201-203; three conduits 271, 272 and 273 connecting the conduit 232 to, respectively, the conduits 241, 242 and 243; and three temperature control valves, TCVs, 281, 282, 283 disposed along the conduits 271, 272, 273, respectively, to distribute the warmed sprayed water flowing out from the condenser 22 based on the energy demand to maintain the set temperatures of the sprayers 211-213.

[0073] In order to circulate water sprayed by the sprayers 211-213 of the tunnel zones 201-203, the circuit further includes: a conduit 251 connecting an opening 254 defined at the bottom of the zone 201 to the sprayers 219 of the zone 209; a conduit 252 connecting an opening 255 define at the bottom of the zone 202 to the sprayers 218 of the zone 208; and a conduit 253 connecting an opening 256 defined at the bottom of the zone 203 to the sprayers 217 of the zone 207. The circuit further includes three pumps 264, 265, 266 disposed along the conduits 251, 252, 253, respectively, and configured to pump, through the openings 254-256 and the respective conduits 251-253, some of the sprayed present at the bottom of the tunnel zones 201-203 to the sprayers 219, 218, 217 of the tunnel zones 209, 208, 207.

[0074] With still reference to Figure 7, a circuit is also provided to recirculate sprayed hot water drained from an opening 290 defined at the bottom of the central tunnel zone 204 to the sprayers 204, 205, 206 of the central tunnel zones 204-206, based on the energy demand to maintain their set temperatures.

[0075] In particular, the circuit comprises: a conduit 291 having a first end connected to the opening 290 and a second end connected to a first opening of an intermediate atmospheric tank 292 (hot tank 292) for storing the drained sprayed water; a conduit 293 connected to a second opening of the hot tank 292 and passing through a heater 68 (e.g., a steam heater exchanger); and a pump 295 positioned along the conduit 293 (between the hot tank 292 and the heater 68) and configured to pump water stored in the hot tank 292 through the conduit 293 (thus causing a continuous flow of sprayed water from the bottom of the zone 204 into the hot tank 292, and from the hot tank 292 through the heater 68).

[0076] The circuit further comprises: three conduits 294, 295, 296 (connecting openings defined at the bottom of the zones 204, 205, 206 to the their sprayers 214, 215, 216); three pumps 297, 298, 299 (disposed along the conduits 294, 295, 296); and three TCVs 94, 95, 96 disposed along three conduits 91, 92, 93 (to distribute the hot sprayed water flowing out from the heater 68 based on the energy demand to maintain the set temperatures for the central zones 204-207).

[0077] With still reference to Figure 7, when there are first time periods during which no containers filled with liquid foodstuff are available to be thermally processed by the tunnel pasteurizer 200 but liquid foodstuff is flowing through the evaporator 21, the warmed sprayed water flowing out from the condenser 22 can be advantageously stored in the warm tank 231 (by operating a valve 234 to allow flow of the warmed sprayed water into the tank 231).

[0078] When there are second time periods during which no liquid foodstuff is flowing through the evaporator 21 but containers filled with liquid foodstuff are available to be thermally processed by the tunnel pasteurizer 200, the valve 234 can be operated to allow flow of the warmed sprayed water stored in the tank 231 (during the first time periods) to the TCVs 281- 283, passing through the condenser 22 (without being warmed by heat exchange with liquid foodstuff). In this way, the tank 231 can recirculate warmed sprayed water through the lateral tunnel zones 207-209, 201-203 (at least for a limited time depending on the amount of stored warmed water and the tank volume).

[0079] Furthermore, in an emergency case where the heat pump 20 stops to operate, a valve 66 can be operated so as to provide some of the hot sprayed water flowing through the conduit 93 to the warm tank 231 (thus warming the sprayed water stored in the tank 231). In this way, the tank 231 can work as a buffer to recirculate warmed sprayed water through the lateral tunnel zones 201-203, 207-209, via the TCVs 281-283, even if the heat pump 20 stops to operate. Concerning the use of the hot tank 292 as a buffer, when there are first time periods during which no containers filled with liquid foodstuff are available to be thermally processed by the tunnel pasteurizer 200 but sprayed water collected from the opening 290 of the central tunnel zone 204 is flowing through the heat exchanger 68, the warmed sprayed water flowing out from the heat exchanger 68 can be advantageously stored in the tank 292 (by operating a valve 67 to allow flow of the warmed sprayed water into the tank 292).

[0080] When there are second time periods during which the heat exchanger 68 is not operating but containers filled with liquid foodstuff are available to be thermally processed by the tunnel pasteurizer 200, the valve 67 can be operated to allow flow of the warmed sprayed water stored in the tank 292 (during the first time periods) to the TCVs 94-96 (passing through the heat exchanger 68 without being warmed). In this way, the tank 292 can recirculate warmed sprayed water through the tunnel central zones 204-206 (at least for a limited time depending on the amount of stored warmed water and the tank volume). Furthermore, a valve 2950 may be used to cause a flow of some of the warmed sprayed water stored in the tank 231 to the tank 292.

[0081] An exemplary operation of the system 150 to cool liquid foodstuff is disclosed with reference now to the Figure 8, illustrating for example the thermal cycle of beer undergoing, during the continuous line process, first the cooling process operated by the heat pump 20 and then (after being poured in the containers) the heating process operated by the tunnel pasteurizer 200.

[0082] As illustrated in portion 63 of Figure 8: the values of the set temperatures of the water sprayed in the lateral tunnel zones 201, 202, 203 are, respectively, 30 °C, 39 °C and 49 °C (suitable for causing an increase of temperature of the cold beer within the containers from about 5°C to about 37 °C); the value of the set temperatures of the water sprayed in the central zones 204-205 is about 63 °C (suitable for causing a further increase of temperature of the beer within the containers from 37 °C to a pasteurization temperature of about 60 °C); the value of the set temperature of the water sprayed in the central zone 206 is about 61 °C (suitable for maintaining the reached pasteurization temperature); and the values of the set temperatures of the water sprayed in the lateral zones 207, 208, 209 are, respectively, about 47 °C, 37 °C and 29 °C (suitable for causing a decrease of temperature of the beer within the containers from about 60 °C to 35 °C).

[0083] Starting from the tunnel lateral zone 207, the pump 233 causes a flow of water sprayed in the tunnel zone 207 (at a temperature of about 45 °C after being in contact with containers filled with beer at a lower temperature), from the opening 228 to the warm tank 231, and from the warm tank 231 to the condenser 22 of the heat pump 20.

[0084] As illustrated in portion 64 of Figure 8, the thermal exchange operated by the heat pump 20 results in a temperature decrease of the beer flowing through the evaporator 21 from 18 °C to about 5 °C, and in a corresponding temperature increase of the sprayed water flowing through the condenser 22 from 45 °C to about 50 °C.

[0085] With reference now to portion 65 of Figure 8, a certain time is needed for the cooled beer to continue its flow until reaching the filling machine 11 and, once bottled / canned, to reach the tunnel pasteurizer 200. In the meantime: the TCV 283 is controlled to mix sprayed water drained through the opening 246 (including: water sprayed by the sprayers 218 of the zone 208, flowing into the bottom potion of the zone 207 via the opening 226, at a temperature of about 35 °C; and some of the water sprayed by the sprayers 217 of the zone 207, at a temperature of about 45 °C after being in contact with filled containers) with a first amount of the warmed water (at 50 °C) flowing through the conduit 232, required to obtain mixed water at the set temperature of 49 °C (that is provided, by the pump 263, to the sprayers 213 of the lateral zone 213); the TCV 282 is controlled to mix sprayed water drained through the opening 245 (including: water sprayed by the sprayers 219 of the zone 209, flowing into the bottom potion of the zone 208 via the opening 227, at a temperature of about 27 °C; and some of the water sprayed by the sprayers 218 of the zone 208, at a temperature of about 35 °C after being in contact with filled containers) with a second amount of the warmed water (at 50 °C) still flowing through the conduit 232, required to obtain mixed water at the set temperature of 39 °C (that is provided, by the pump 262, to the sprayers 212 of the lateral zone 202); and the TCV 281 is controller to mix water sprayed by the sprayers 219 (at a temperature about of about 27 °C after being in contact with filled containers) with a third amount of the warmed water (at 50 °C) still flowing through the conduit 232, required to obtain mixed water at the set temperature of 30 °C (that is provided, by the pump 261, to the sprayers 211 of the first zone 201).

[0086] Water sprayed by the sprayers 211, 212, 213 (at a temperature of 29 °C, 37 °C and 47 50 °C, respectively, after being in contact with filled containers) is then pumped, through the conduits 251, 252, 253, to the sprayers 219, 218, 217, respectively, of the lateral zones 207, 208, 209.

[0087] It is to be appreciated that since the warmed sprayed water is recirculated only through the lateral tunnel zones 201-203, 307-208 (while sprayed water is separately collected from and recirculated through central zones 204-206), the sprayed water can be collected from the lateral tunnel zone 207, such that the temperature value (50 °C) of the warmed sprayed water flowing out from the condenser 22 is relatively close to the ambient temperature (18 °C) of the beer flowing into the evaporator 21 (resulting in a cop for the pump 20 of about 4.6).

[0088] It is to be further appreciated that by operating a heating pump in cooperation with a tunnel pasteurizer to cool liquid foodstuff, as per the principles disclosed with reference to the embodiment of Figure 7 (and considering different liquid foodstuff and / or collected sprayed liquid temperatures than the temperatures illustrated in Figure 8), the difference in temperature between the liquid foodstuff flowing into the evaporator 21 and the warmed sprayed water flowing out from the condenser 22 is generally lower than 55 °C (resulting in a cop greater of about 3.5), and can range for example down to 25 °C (resulting in a cop for the heat pump ranging up to about 5).

[0089] With reference now to Figure 13, there is illustrated an alternative system 300 for cooling carbonated liquid foodstuff using the heat pump 20 in cooperation with the tunnel pasteurizer 200, substantially differing from the system 150 illustrated in Figure 7 in that sprayed water is collected from the central zone 204 of the tunnel pasteurizer and distributed, after passing through the condenser 22 of the heat pump 20, to all the tunnel zones 201-209 (according to amounts required to maintain the set temperatures of the sprayers 211-219).

[0090] Accordingly, the circuit used in the system 300 to collect and distribute sprayed water differs from the circuit used in the system 150 illustrated in Figure 7 in that: a conduit 302 is used to allow a flow (caused by a pump 303) of sprayed water from an opening 301 defined at the bottom of the central zone 204 to a first opening defined at a first side of the top portion of a stratification tank 305, passing through the condenser 22 of the heat pump 20; a conduit 307 (including a pump 308 close to the top portion of the tank 305) extends from a second opening defined at a second side of the top portion of the stank 305 for distributing warmed sprayed water not only to the conduits 271, 272, 273 of the tunnel lateral zones 207-209 (including the TCVs 281, 282, 283) but also to the conduits 91, 92, 93 associated to the tunnel central zones 204-206 (including the TCVs 94, 95, 96).

[0091] The tank 305 (that is connected via a valve 306 to the portions of the conduit 302 between the opening 301 and the condenser 22) can be used as a buffer for storing warmed water provided by the heat pump 20 that can be recirculated, when required, through the tunnel zones 201- 209 (in a similar way as previously disclosed in relation to the buffer stratification tank 80 used in the embodiment of Figure 6).

[0092] Furthermore, the system 300 of Figure 13 includes a heater 304 (e.g., a steam heater exchanger) for further increasing the temperature of the warmed sprayed water flowing out from the condenser 22 (before reaching the top portion of the tank 305). In this way, the flow rate of warmed water towards the TCVs can be maintained at an adequate level although the higher thermal energy required to maintain the set temperatures for the water sprayed in all the nine tunnel zones 201-209.

[0093] It is to be further appreciated that by operating a heating pump in cooperation with a tunnel pasteurizer to cool liquid foodstuff, as per the principles disclosed with reference to the embodiment of Figure 13, the difference in temperature between the liquid foodstuff flowing into the evaporator 21 and the warmed sprayed water flowing out from the condenser 22 is generally lower than 75 °C (resulting in a cop greater of about 2.5), and can range for example down to 55 °C (resulting in a cop ranging up to about 3.5).

[0094] With reference now to Figure 9, there is illustrated a system 350 for recovering thermal energy in a non-carbonated liquid foodstuff production plant.

[0095] In particular, a filling machine 11 is used to fill containers with prepared non-carbonated liquid foodstuff, wherein he preparation of the liquid foodstuff involves flash-pasteurization (performed by a pasteurization module 12) followed by the filling of containers with the liquid foodstuff at a high temperature into the containers (hot filling).

[0096] After hot filling, the filled containers are moved (e.g., by one or more auxiliary conveyors) until reaching the conveyor 2 that is used to move the filled containers through a tunnel cooler 400 present in the foodstuff processing line. The tunnel cooler 400 comprises four zones 401, 402, 403, 404 having respective sprayers 411, 412, 413, 414 arranged at top portions of the zones 401, 402, 403, 404 and configured to spray water, at respective set temperatures, on the filled containers moved by the conveyor 2 through the four zones 401- 404 (starting from the zone 401). The set temperatures are suitable to cause a controlled gradual decrease of the temperature of the liquid foodstuff within the moved containers (to reach an ambient temperature or at least a temperature that avoids damaging of the containers).

[0097] The bottom portions of adjacent tunnel zones are in communication via respective openings 415, 416, 417 so as to allow a limited flow of sprayed water between adjacent tunnel zones (such that to balance the level of sprayed water at the bottom portions of the tunnel zones). In particular: water sprayed in the zone 404 can flow, through the opening 417, into the bottom portion of the zone 403; water sprayed in the zone 403 can flow, through the opening 416, into the bottom portion of the zone 402; and water sprayed in the zone 402 can flow, through the opening 415, into the bottom portion of the zone 401.

[0098] In order to pre-heat the liquid foodstuff before reaching the pasteurization module 12, the system 350 comprises: a conduit 23 passing through the condenser 22 of the heat pump 20 (to allow a continuous flow of liquid foodstuff through the condenser 22); a conduit 351 connected to an opening 352 defined at the bottom of the first tunnel zone 401 and passing through the evaporator 21; and a pump 353 positioned along the conduit 351 and configured to pump sprayed water reaching the bottom of the first zone 101 through the opening 352 and conduit 351 (thus causing a continuous flow of the drained water through the evaporator 21). Before reaching the evaporator 21, the conduit 351 flows through a heat exchanger 354. The heater exchanger 354 includes a conduit 355 to allow a flow of refrigerant (e.g., propylene glycol or cooling tower water), thereby allowing transfer of thermal energy from the drained sprayed water flowing through the conduit 351 to the refrigerant flowing through the conduit 355. The warmed refrigerant is provided back to an external cooling source, and then recirculated through the heat exchanger 354.

[0099] The temperature of the cooled sprayed water flowing out from the heat exchanger 354 is further decreased by providing thermal energy, via the heat pump 20, to the liquid foodstuff under preparation.

[0100] In particular, with reference now to Figure 10, the refrigerant flowing (in a liquid form at a cold temperature) through the evaporator 21 absorbs heat from the sprayed water flowing at the same time through the evaporator 21. Then, the refrigerant flows through the compressor 33 that increases the pressure (and temperature) of the refrigerant so as to cause a change of its state from liquid to gas. The refrigerant in the gas form flows through the condenser 22, transferring the heat received from the sprayed water to the liquid foodstuff that is flowing, at the same, through the condenser 22. Then, the cooled refrigerant flows through the expansion valve 36 that causes a drop of pressure (and temperature) of the refrigerant, thus changing its state from gas back to liquid. The liquid and cooled refrigerant is then recirculated through the evaporator 21, restarting the thermal cycle in the heat pump 20.

[0101] In order to recirculate the cooled sprayed water flowing out from the evaporator 21 through the tunnel zones 401-404, the conduit 351 is connected to an opening 385 defined at the bottom of the last tunnel zone 404, and the system 350 further includes: four conduits 361, 362, 363, 364 connecting, respectively, opening 371, 372, 373, 374 defined at the bottom of the tunnel zones 401, 402, 403, 404 to the sprayers 411, 412, 413, 414; and four pumps 381, 382, 383, 384 positioned through the conduits 361, 362, 363, 364, respectively, and configured to pump, through the openings 371-374 and the respective conduits 361-364, some of the sprayed water at the bottom of the tunnel zones 401-404 to their sprayers 411-414.

[0102] An exemplary operation of the system 350 is disclosed with reference now to the Figure 11, illustrating the thermal cycle of an exemplary liquid foodstuff undergoing, during the continuous line process, a pre-heating process operated by the heat pump 20 and then a flashpasteurization process operated by the module 12.

[0103] As illustrated in portion 391 of Figure 11, the values of the set temperatures of the sprayers 411-414 are, respectively, 50 °C, 40 °C, 30 °C and 20 °C suitable for causing a temperature decrease of the hot foodstuff within the moved containers from about 85° C to about 35 °C. Starting from the first tunnel zone 401, sprayed water present at the bottom of the zone 401 is pumped through the opening 352 and the conduit 351, so as to flow through the heater exchanger 354 that reduces the temperature of the sprayed water to about 19 °C.

[0104] The cooled sprayed water then flows through the evaporator 21. As illustrated in portion 392 of Figure 11, the thermal exchange operated by the heat pump 20 results in a temperature increase of the liquid foodstuff from 25 °C to about 38 °C, and in a corresponding temperature decrease of the sprayed water from 19 °C to about 10 °C.

[0105] It is to be appreciated that due to the proximity of the temperature values of the liquid foodstuff flowing out from the condenser 22 and the sprayed water flowing into the evaporator 21, the cop of the pump 20 is particularly high (about 6).

[0106] It is to be further appreciated that by operating a heating pump in cooperation with a tunnel cooler to heat the liquid foodstuff, as per the principles disclosed with reference to the embodiment of Figure 9 (and considering different liquid foodstuff and / or collected sprayed liquid temperatures than the temperatures illustrated in Figure 11), the difference in temperature between the sprayed water flowing into the evaporator 21 and the heated liquid foodstuff flowing out from the condenser 22 is generally lower than 30 °C (resulting in a cop greater of about 4.5), and can range for example down to 15 °C (resulting in a cop ranging up to about 6.5).

[0107] With reference now to portion 393 of Figure 11, the liquid foodstuff flowing out from the condenser 22 undergoes the flash pasteurization process operated by the module 12 (e.g., using a flow of heated water), so as to further increase the temperature of the pre-heated liquid foodstuff from 38 °C to the pasteurization temperature of about 120°C. A controlled decrease of the temperature (e.g., using a flow of cold water) from 120 °C to about 85 °C is then operated (within the module 12 or by another separated cooling module). As illustrated in portion 394 of Figure 11, a certain time is needed for the cooled liquid foodstuff to continue its flow until reaching the filling machine 11 and, once poured into containers, to reach the tunnel cooler 400.

[0108] In the meantime, the cooled sprayed water flowing out from the evaporator 21 (at about 10 °C) is provided, via the opening 385, to the bottom of the last tunnel zone 404, where it mixes with water sprayed by the sprayers 414 (at a temperature of about 22 °C after having been in contact with the filled containers moved through the zone 404). Some of this mixed water (at a temperature of about 20 °C) is pumped, through the opening 374 and the conduit 364, to the sprayers 414 (to be re-sprayed in the zone 404), while some of the mixed water flows, through the opening 417, into the bottom of the preceding tunnel zone 403.

[0109] At the bottom of the tunnel zone 403, the sprayed water flowing from the zone 404 mixes with water sprayed by the sprayers 413 (at a temperature of about 32 °C after having been in contact with the filled containers moved through the zone 403). Some of this mixed water (at a temperature of about 30 °C) is pumped, through the opening 373 and the conduit 363, to the sprayers 413 (to be re-sprayed in the zone 403), while some of the mixed water flows, through the opening 416, into the bottom of the preceding tunnel zone 402.

[0110] At the bottom of the tunnel zone 402, the sprayed water flowing from the zone 403 mixes with water sprayed by the sprayers 412 (at a temperature of about 42 °C after having been in contact with the filled containers moved through the zone 402). Some of this mixed water (at a temperature of about 40 °C) is pumped, through the opening 372 and the conduit 362, to the sprayers 412 (to be re-sprayed in the zone 402), while some of the mixed water flows, through the opening 415, into the bottom of the first tunnel zone 401.

[0111] At the bottom of the tunnel zone 401, the sprayed water flowing from the zone 402 mixes with water sprayed by the sprayers 411 (at a temperature of about 52 °C after having been in contact with the filled containers moved through the zone 401). Some of this mixed water (at a temperature of about 50 °C) is pumped, through the opening 371 and the conduit 361, to the sprayers 411 (to be re-sprayed in the zone 401), while some of the mixed water flows, through the opening 352 and conduit 351, towards the heat exchanger 354.

[0112] It is to be appreciated that the amount of cooled sprayed water provided, via the opening 385, to the bottom portion of the last tunnel zone 404, in order to obtain mixed water at about 20 °C, can be controlled using a TCV (not illustrated in Figure 9) arranged along the conduit 351 (between the evaporator 21 and the opening 385).

[0113] With reference now to Figure 12, the system 350 illustrated in Figure 9 is modified to include a stratification tank 450 that works as a buffer for storing cold water provided by the heat pump 20 that can be recirculated, when required, through the zones 401-404 of the tunnel cooler 400.

[0114] In particular, a top portion of the tank 450 is connected, via a valve 451, to a first portion 351a of the conduit 351 (between the opening 352 and the evaporator 21 and before the pump 353). A second portion 351b of the conduit 351 extends from the evaporator 21 to a first opening defined at a first side of the bottom portion of the tank 450. A conduit 452 extends from a second opening defined at a second side of the bottom portion of the tank 450 and is connected to the opening 385 of the last tunnel zone 404. A pump 453 is disposed through the conduit 452 (close to the bottom portion of the tank 405).

[0115] In operation under normal conditions (where liquid foodstuff is continuously flowing through the condenser 22 and containers filled with liquid foodstuff are continuously moved through the tunnel zones 201-104), the valve 451 is operated to allow a flow of the sprayed water drained from the first tunnel zone 401 towards the heat exchanger 354 and the heat pump 20 (while preventing a flow towards the top portion of the tank 450), and the pump 453 is operated to cause a flow of the sprayed water cooled by the heat pump 20 into the bottom portion of the tank 450, and from the bottom portion of the tank 450 to the last tunnel zone 404.

[0116] When there are first time periods during which no containers filled with liquid foodstuff are available to be thermally processed by the tunnel cooler 400 but liquid foodstuff is flowing through the condenser 22, the sprayed water cooled by flowing through the evaporator 21 can be advantageously stored in the tank 450 during these first periods.

[0117] When there are second time periods during which no liquid foodstuff is flowing through the condenser 22 but containers filled with liquid foodstuff are available to be thermally processed by the tunnel cooler 400, the valve 451 can be operated to divert the flow of sprayed water drained from the first tunnel zone 401 towards the top portion of the tank 80, while cold water stored in the bottom portion of the tank 450 during the first periods can be pumped to the opening 385 of the last tunnel zone 404. In this way, the tank 450 is used to provide cooled sprayed water through the tunnel zones 401-404 (at least for a limited time depending on the amount of stored cooled water and the tank volume).

[0118] Modifications

[0119] Although this disclosure has been described with reference to particular embodiments of the present invention, it should be understood that various omissions, substitutions and changes in the form and details of the disclosed embodiments as well as other embodiments are possible.

[0120] For example, the number of tunnel zones for the tunnel machines 100, 200, 400 can be different than the number illustrated in the Figures (even encompassing the case of singlezone tunnel machines).

[0121] For example, sprayed water to be recirculated (after passing through the heat pump 20) can be collected from a zone different than the tunnel zones 103, 207, 204 and 404 (as illustrated in the embodiments of Figures 1, 7, 13 and 9). Furthermore, although in the embodiments of Figures 1, 7, 9 and 13 sprayed water is drained from only one tunnel zone, sprayed water to be provided to the heat pump 20 can be drained from more tunnel zones.

[0122] For example, although in the embodiments illustrated in Figure 1 and 9 warmed / cooled sprayed water flowing out from the heat pump 20 is recirculated through all the zones of the tunnel warmer 200 / tunnel cooler 400, in some embodiments the warmed / cooled sprayed water can be recirculate only through a subgroup of the tunnel zones.

[0123] For example, although in the embodiments illustrated in Figures 1, 7 and 13 the heat pump 20 is used to cool liquid foodstuff already carbonated, in some embodiments the heat pump 20 can be used to cool liquid foodstuff not yet carbonated (but already mixed with substances, if required). In these embodiments, the conduit 23 extending out from the evaporator 21 can be connected to a carbonating machine disposed, along the foodstuff process line, before the filling machine 11 (in the same or a different hall). Is some other alternative embodiments, the heat pump 20 can be used to cool liquid foodstuff not yet mixed (as required) with substances (but already carbonated). In these embodiments, the conduit 23 can be connected to a mixing machine positioned, along the foodstuff processing line, before the filling machine 11 (in the same or a different hall), so as to allow a flow of the cooled carbonated liquid foodstuff into the mixing machine. In some other alternative embodiments, the heat pump 20 can be used to cool liquid foodstuff not yet carbonated and not yet mixed (as required) with one or more substances. In these embodiments, the conduit 23 can by connected to the one of a mixing machine and a carbonating machine preceding the other along he foodstuff production line.

[0124] With reference to Figures 9, if the liquid foodstuff under preparation needs to be mixed with one or more substances, a mixing machine can be disposed, along the foodstuff process line, between the heat pump 20 and the filling machine 11 (before or after the pasteurization module 12). Alternatively, the heat pump 20 can be used to cool liquid foodstuff already mixed with one or more substances by a mixing machined disposed, along the foodstuff process line, before the heat pump 20.

[0125] Although the heat pump configuration illustrated in Figure 3 have been disclosed in relation to the embodiment illustrated in Figure 1, the same configuration (with inclined evaporator 21 and condenser 22) can be used in other embodiments according to the present invention. In this regard, it is to be noted that in some embodiments only one of the evaporator and condenser is inclined. Furthermore, although in the embodiment of Figure 3 the evaporator 21 and the condenser 22 are tubular heat exchangers, it is to be noted that plated heat exchanges, such as food grade plated heat exchangers, can be alternative used (inclined or not).

[0126] Furthermore, although the embodiments illustrated in Figures 5 and 13 use heater exchanger 71 and 304 to increase temperature of collected sprayed water, other types of heaters can be used (e.g., electrical heaters).

[0127] Furthermore, an atmospheric tank may be used instead of the stratification tank 80 illustrated in Figure 6, and / or the stratification tank 305 illustrated in Figure 13, and / or the stratification tank 450 illustrated in Figure 12.

[0128] With reference to Figure 6, a heater (such as the heater 71 illustrated in Figure 5) can be connected to the portion 25b of the circuit 25 (to be used in alternative to or in cooperation with the heat pump 20 to warm the sprayed liquid collected from the tunnel warmer 100). With reference to the embodiment illustrated in Figure 9, it is to be further noted that the presence of a heat exchanger to cool the drained sprayed water before reaching the evaporator 21 of the heat pump 20 is optional in some applications.

[0129] Finally, it is to be noted that even in the disclosed embodiments water is sprayed in the tunnel machines 100, 200, 400, other suitable liquids can be sprayed. Furthermore, liquid can be applied in the tunnel machines without being sprayed, e.g., by immersion of the containers filled with liquid foodstuff into the liquid.

Claims

Claims:

1. A liquid foodstuff production plant comprising: a filling machine (11) configured to fill containers with liquid foodstuff; a thermal treatment tunnel machine (100, 200, 400); a conveyor (2) configured to move the filled containers through the tunnel machine, wherein the tunnel machine is configured to apply liquid to the filled containers moved by conveyor so as to cause a temperature change of the liquid foodstuff within the containers; and a system (10, 150, 300, 350) for recovering thermal energy in the liquid foodstuff production plant, the system comprising: a heat pump (20); a conduit (23) passing through the heat pump to allow a flow of liquid foodstuff through the heat pump, before the liquid foodstuff reaches the filling machine; and a circuit configured to collect at least some of the liquid applied to the filled containers from the tunnel machine and to recirculate the collected liquid through the tunnel machine, the circuit passing through the heat pump to allow a flow of the collected liquid through the heat pump before being recirculated through the tunnel machine; wherein the heat pump is configured to exchange thermal energy between the liquid foodstuff and the collected liquid flowing therethrough, so as to warm one of the liquid foodstuff and the collected liquid and cool the other of the liquid foodstuff and the collected liquid.

2. The system of claim 1, wherein a difference in temperature between the warmed one of the liquid foodstuff and the collected liquid, flowing out from the heat pump (20), and the other one of the liquid foodstuff and the collected liquid, before flowing into the heat pump (20), is less than 75 °C.

3. The system (10, 150, 300) of any of the preceding claims, wherein: the tunnel machine (100, 200, 400) comprises a plurality of zones (101-103, 201-209, 401-404) having respective liquid applicators (104-106, 211-219, 411-414) configured to apply liquid, at respective set temperatures, to the filled containers moved by the conveyor so as to cause said temperature change of the liquid foodstuff within the containers, and said circuit is configured to collect at least some of the liquid applied to the filled containers from at least a first zone (103, 207, 401) of the tunnel machine (100, 200, 400) andto recirculate the collected liquid to the liquid applicators (104-106; 211-213, 217-219; 411- 414) of at least a group (101-103; 201-203, 207-209; 401-404) of zones of the tunnel machine (100, 200, 400) including the first zone.

4. The system of any of the preceding claims, wherein: said temperature change of the liquid foodstuff within the containers comprises a temperature increase; the heat pump (20) comprises an evaporator (21), a condenser (20), and an internal circuit (30) to allow a flow of a refrigerant fluid through the evaporator and the condenser, and said conduit (23) and circuit pass through the evaporator (21) and the condenser (22), respectively, so as thermal energy is removed by the refrigerant fluid from the liquid foodstuff flowing through the evaporator (21) and provided by the refrigerant to the collected liquid flowing through the condenser (22), thereby warming the collected liquid and cooling the liquid foodstuff.

5. The system of claim 4, wherein said circuit comprises: a plurality of conduits (51-53, 241-243) each connecting an opening (44-46, 244-246) defined at a bottom portion of a respective one of said at least a group of zones (101-103, 207-209) to the liquid applicator (104-106, 211-213) of a respective target zone of said group of zones; a plurality of pumps (41-43, 261-263) each positioned along a respective one of said conduits (51-53, 241-243) and configured to pump, through the respective conduit (51-53, 241-243), some of the liquid applied to the filled containers to the liquid applicator (104-106, 211-213) of the respective target zone; and a plurality of temperature control valves, TCVs (47-49, 281-283) each connected to a respective one of said conduits (51-53, 241-243) and configured to be actuated to mix an amount of warmed collected liquid flowing out from the condenser (22) of the heat pump (20) with liquid flowing towards the pump (41-43, 261-263) disposed along the respective conduit (51-53, 241-243), such that to maintain the set temperature of the liquid applied by the liquid applicator (104-106, 211-213) of the respective target zone.

6. The system (10) of any of claims 1-5, wherein the tunnel machine is a tunnel warmer (100).

7. The system of claim 6, wherein a difference in temperature between the warmed liquid flowing out from the condenser (22) and the liquid foodstuff before flowing into the evaporator (21) is less than 30 °C.

8. The system (150) of claim 4 or claim 5, wherein the tunnel machine is a tunnel pasteurizer (200).

9. The system of claim 8, wherein said plurality of zones (201-209) comprises: at least one first lateral zone (201-203) comprising a liquid applicator (211-213) configured to apply liquid, at a respective first temperature, to the filled containers moved by the conveyor so as to cause a temperature increase of the liquid foodstuff within the containers, at least one central zone (204-206) after said at least one first lateral zone, comprising a liquid applicator (214-216) configured to apply liquid, at a respective second temperature greater than the first temperature, to the filled containers moved by the conveyor so to cause a further temperature increase of the liquid foodstuff within the containers to a pasteurization temperature, and at least one second lateral zone (207-209) after said at least one central zone, comprising a liquid applicator (217-219) configured to apply liquid, at a respective third temperature lower than the second temperature, to the filled containers moved by the conveyor so as to cause a temperature decrease of the foodstuff within the containers; and wherein said first zone of the tunnel machine corresponds to one zone (207) of said at least one first lateral zone (201-203) and said at least one second lateral zone (207-209), and wherein said group of zones of the tunnel machine (200) includes said at least one first lateral zone and said at least one second lateral zone (201-203, 207-209).

10. The system of claim 9, wherein a difference in temperature between the warmed liquid flowing out from the condenser (22) and the liquid foodstuff before flowing into the evaporator (21) is less than 55 °C.

11. The system (350) of any of claims 1-3, wherein: said tunnel machine is a tunnel cooler (400) and said temperature change of the liquid foodstuff within the containers corresponds to a decrease of temperature;the heat pump (20) comprises an evaporator (21), a condenser (22) and an internal circuit (30) to allow a flow of a refrigerant fluid through the evaporator and the condenser; and said conduit (23) and said circuit pass through the condenser (22) and the evaporator (21), respectively, so as thermal energy is removed by the refrigerant fluid from the collected liquid flowing into the evaporator (21) and provided by the refrigerant to the liquid foodstuff flowing through the condenser (22), thereby cooling the collected liquid and warming the liquid foodstuff.

12. The system of claim 11, wherein a difference in temperature between the warmed liquid foodstuff flowing out from the condenser (22) and the collected liquid before flowing into the evaporator (21) is less than 30 °C.

13. The system of any of the preceding claims, wherein said circuit comprises a first portion (25a, 351a) to allow a flow of the liquid collected from the tunnel machine (100, 400) towards the heat pump (20) and a second portion (25b, 28; 351b, 452) to allow a flow of the collected liquid from the heat pump (20) to the tunnel machine (100, 400), and wherein the system (10, 350) further comprises a liquid tank (80, 450) having: a first end connected, via a valve (81, 451), to the first portion (25a, 351a) of the circuit, the valve being configured to be operated to divert the flow of the collected liquid towards the first end of the liquid tank (80, 450) instead of towards the heat pump (20); and a second end opposed to the first end and connected to the second portion (25b, 28; 351b, 452) of said circuit.

14. The system of claim 4 or claim 11, wherein at least one of: the evaporator (21) is inclined to facilitate drainage of foodstuff from the heat pump (20); and the condenser (22) is inclined to facilitate drainage of refrigerant from the condenser (22).

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