METHOD FOR CONTROLLING THE TEMPERATURE OF DINING UTENSES USED IN A CART, APPARATUS AND CART FOR CARRYING OUT THE METHOD

Description

Technical Field

[0001] The present invention relates to the field of transporting and distributing meals using trays, on which are placed food and various utensils necessary for consuming the food.

[0002] The object of the invention relates more specifically to the management of the reheating of meal trays placed inside an insulated transport trolley.

[0003] The object of the invention finds a particularly advantageous application, but not exclusively, in the field of transport and distribution of meal trays, particularly in the health sector and in penitentiary establishments. Previous technique

[0004] Typically, a meal tray is designed to hold hot and cold dishes in containers appropriate to the type of food. In the hot food delivery system, hot dishes are transported and kept at serving temperature immediately after preparation until they are served to the consumer. In the chilled food delivery system, hot dishes are brought to serving temperature just before being served, having been rapidly cooled immediately after preparation for cold storage that can last for several days.

[0005] The transport and distribution of such meal trays are generally carried out using insulated trolleys designed to offer two separate compartments. One compartment holds the trays containing utensils and cold food, while the other holds the containers for hot food. The hot compartment is equipped with heating elements to place and maintain the hot food at its serving temperature. According to the embodiment described in French patent FR 2 831 682, the heating elements are superimposed heating plates, each allowing for the individual reheating of the hot food on the meal tray placed next to it.

[0006] This insulated transport trolley includes a control unit that manages the operation of the heating plates. This control unit is connected to a system that detects the presence of meal trays, thereby inhibiting the operation of the heating plates when no tray is present. These tray detection systems help reduce the energy consumption of the insulated transport trolleys. However, the actual operating conditions of this insulated transport trolley remain unknown. In a service that serves meal trays, the capacity of the insulated transport trolleys is generally adapted to the number of trays to be distributed. However, in practice, meal trays are frequently added to or removed from these trolleys before they have been reheated.This presents a challenge in optimizing the reheating process for meal trays placed in insulated transport trolleys. Specifically, it is difficult to determine the appropriate trolley capacity based on the actual number of meal trays to be reheated. Furthermore, the electrical power supply for these trolleys is insufficient to meet the power requirements for reheating them. Description of the invention

[0007] The object of the invention is therefore to remedy the disadvantages of the prior art by proposing a method to optimize the operation of reheating meal trays in an insulated transport trolley.

[0008] Another object of the invention is to propose a method for managing the reheating of meal trays offering flexible operating conditions for these insulated transport trolleys.

[0009] To achieve these objectives, the method according to the invention aims to manage the reheating of meal trays inserted inside an insulated meal tray transport trolley, according to the following method: * at least one insulated transport trolley is made available, comprising a series of superimposed heating plates, each configured to ensure the individual reheating of a meal tray inserted inside the insulated transport trolley, * the operation of the heating plates is controlled to ensure the reheating of the meal trays, * the heating plates used to achieve effective reheating of the meal trays are detected, * and the heating plates used to achieve effective reheating of the meal trays are counted.

[0010] According to an implementation characteristic, to detect the presence of a meal tray positioned to be reheated by a heating plate, the evolution of the temperature of the heating plate is analyzed.

[0011] Depending on the preferred implementation characteristic, the evolution of the heating plate temperature is analyzed by comparing it with at least one reference evolution of the heating plate temperature.

[0012] Advantageously, the temperature evolution of the heating plate is compared with at least: * a reference evolution of the heating plate temperature for which the meal tray is absent, * a reference evolution of the heating plate temperature for which the meal tray is present, * and a reference evolution of the heating plate temperature for which the meal tray does not contain any food to be reheated.

[0013] According to an operating characteristic, the operation of all heating plates is controlled and the operation of the heating plates is interrupted for each of them whose temperature evolution of the heating plate does not correspond to a reference temperature evolution of the heating plate for which the meal tray is present.

[0014] According to another operating characteristic, for each heating plate, the presence of a meal tray positioned to be reheated by said heating plate is detected before it is ordered into operation, and only the heating plates for which the meal trays are positioned to be reheated are controlled in operation.

[0015] According to an advantageous feature of the invention, in order to detect the heating plates used to achieve effective reheating of the meal trays, the heating plates used for a determined time and / or reaching a determined temperature are determined.

[0016] For example, the heating plates used to effectively reheat meal trays are determined based on a heating plate operating time of between 2 and 10 minutes.

[0017] Advantageously, each insulated trolley for transporting meal trays transmits to a centralized management center the number of heating plates used to effectively reheat the meal trays.

[0018] Preferably, the centralized management center determines, based on the number of heating plates used to effectively reheat meal trays, a cost of using the insulated transport trolley.

[0019] Another object of the invention is to provide an insulated trolley for transporting meal trays comprising: * an insulating envelope internally delimiting at least one compartment accessible by at least one door, * a support structure arranged inside the enclosure, to hold meal trays in a stacked position, * a series of individual heating plates for a meal tray held in position by the support structure, * a system to manage the reheating of the meal trays by the heating plates, this system comprising: .a detection device for each heating plate, of the presence of a meal tray positioned to be reheated by said heating plate, .a control unit configured to ensure: .. the operation of the heating plates to ensure reheating of the meal trays, ..the detection of the heating plates used to effectively reheat the meal trays, ..the counting of the heating plates used to effectively reheat the meal trays.

[0020] According to a preferred embodiment, the insulated trolley for transporting meal trays includes, as a device for detecting the presence of a meal tray, a temperature probe associated with each heating plate and connected to the control unit, the control unit analyzing the evolution of the temperature of the heating plate and comparing it with at least one reference evolution of the temperature of the heating plate, in order to ensure the operation of the heating plates to ensure effective reheating of the meal trays, at least for the heating plates equipped with a meal tray.

[0021] Preferably, the control unit provides information on the number of heating plates used to effectively reheat the meal trays.

[0022] Advantageously, the control unit includes a communication circuit with a centralized management center.

[0023] Another object of the invention is to provide a management installation for managing the reheating of meal trays inserted inside at least one insulated meal tray transport trolley, this installation comprising at least one centralized management center communicating with the communication circuit of at least one insulated meal tray transport trolley, so as to receive from said trolley, at least the information on the number of heating plates used to achieve effective reheating of the meal trays.

[0024] Advantageously, the centralized management center provides, for each insulated transport trolley, a cost of use of the insulated transport trolley based on the number of heating plates used to achieve effective reheating of the meal trays. Brief description of the drawings

[0025] [ Fig. 1 ] There figure 1 is a schematic perspective view showing an example of an embodiment of an insulated transport trolley implementing the invention. Fig. 2 ] There figure 2 is a functional block diagram illustrating a system for managing the reheating of meal trays in an insulated transport trolley implementing the invention. Fig. 3 ] There figure 3 is a graph showing the evolution of the heating plate temperature depending on the presence or absence of a meal tray. Description of the implementation methods

[0026] As this is more precisely apparent from the figure 1 The object of the invention implements at least one insulated trolley 1 constituting a storage and / or transport unit for a series of meal trays 2. In a conventional manner, the trolley 1 comprises an insulating box or envelope 3 internally delimiting at least one, and in the illustrated example, two compartments 4 accessible from the two opposite sides of the trolley and each closed by at least one door 5.

[0027] Typically, the trolley 1 is adapted to allow cooling of the housing units 4. For this purpose, the trolley 1 can be equipped with a cooling system or can be connected to any system allowing cooling of the housing units 4. Each housing unit 4 is equipped internally with an insulating partition 7 delimiting on either side, a so-called hot compartment 8 and a so-called cold compartment 9.

[0028] Typically, the trolley 1 is equipped with a support and guide structure 11 for the meal trays 2. Typically, this support structure 11 is formed by all elements arranged in a superimposed manner on the walls of the compartments, so as to allow the meal trays to be held at different superimposed levels inside each compartment 4. Typically, this support structure 11 has grooves forming sliding rails for the meal trays 2.

[0029] Each meal tray 2 comprises a first part 12, delimited in the illustrated example by a large cavity, and a second part 13, delimited in the illustrated example by a small cavity. Each meal tray 2 has a junction zone 14 between the cavities 12 and 13. Each meal tray 2 is designed to be inserted into a housing 4 such that the junction zone 14 is positioned opposite the partition 7, which has overlapping slots 15 to allow the insertion and passage of the meal trays 2. Of course, the object of the invention can be implemented with meal trays 2 having a first part 12 and a second part 13 arranged differently and in any way appropriate to the food and utensils used.

[0030] As is more precisely apparent from the figure 1 Each meal tray 2 is positioned inside each compartment 4, so that the junction area 14 is aligned with the insulating partition 7, thus extending the first part 12 and the second part 13 into a hot compartment 8 and a cold compartment 9, respectively. The positioning of the first part 12 and the second part 13 in the hot compartment 8 and the cold compartment 9 depends on whether the food is hot or cold and is placed inside these parts of the meal trays. As illustrated in the Fig. 1 The first part 12 of meal tray 2 is intended to be placed inside the hot compartment 8 while the second part 13 of this meal tray 2 is intended to be placed in the cold compartment 9. Of course, the first part 12 and the second part 13 of the meal trays are arranged according to the size of the hot compartment 8 and cold compartment 9.

[0031] The trolley 1 is equipped with a series of heating plates 18, each providing individual heating for each meal tray 2 to reheat them. More specifically, each heating plate 18 is designed to reheat the hot portion of the meal trays, i.e., the food items arranged on the first section 12 of the trays. The heating plates 18 are mounted inside the hot compartment 8, extending in a stacked fashion below (or even above) each tray level.

[0032] The heating plates 18 are made in any suitable manner. For example, the heating plates 18 are made of resistive or inductive plates extending inside the hot compartment 8 so that the lower face of the first part 12 of each meal tray 2 is in contact with the upper face of a heating plate 18. The heating plates 18 can also each be made of a plate having a heating element in the form of a film or a tubular resistance.

[0033] As this is more precisely apparent from the figure 2 The trolley 1 according to the invention includes a system 20 for managing the reheating of meal trays by heating plates 18. This management system 20 includes a detection device 21 adapted to detect, for each heating plate 18, the presence of a meal tray 2. In other words, the detection device 21 makes it possible to detect, for each heating plate 18, whether a meal tray 2 is positioned to be reheated by said heating plate 18.

[0034] According to a preferred embodiment illustrated in the drawings, the trolley 1 includes, as a sensing device 21, a temperature probe 22 associated with each heating plate 18. For example, each heating plate 18 has a temperature probe such as an NTC thermistor whose resistance decreases as the temperature increases. This temperature probe is attached to the heating plate, for example, by a silicone pad.

[0035] The temperature probes 22 of the heating plates 18 are connected to a control unit 23 that analyzes the temperature evolution of the heating plate as measured by the associated temperature probe 22. The control unit 23 compares this temperature evolution of the heating plate with at least one reference temperature evolution of the heating plate to determine whether or not a meal tray 2 is positioned to be reheated.

[0036] Indeed, it must be considered that the temperature of the heating plate 18 changes differently depending on whether or not a meal tray is placed on the heating plate. figure 3 This illustrates, as an example, the evolution over time t of the temperature T of the heating plate 18 in the presence of a meal tray 2 (curve A) and in the absence of a meal tray 2 (curve B). These curves show that the temperature of the heating plate 18 increases much more rapidly when a meal tray 2 is absent compared to a heating plate 18 equipped with a meal tray. This is explained by the fact that the meal tray and the food absorb heat, so the heating plate 18 with a meal tray heats up less quickly than a heating plate without a meal tray.

[0037] Advantageously, the figure 3 This illustrates, as an example, the evolution over time of the temperature of the heating plate 18 in the presence of an empty meal tray 2, i.e., one without food (curve C). The temperature of such a heating plate 18 increases more rapidly compared to a heating plate 18 equipped with a meal tray 2, but more slowly compared to a heating plate 18 without a meal tray 2.

[0038] Advantageously, such a detection system 21 analyzes the temperature variation of the heating plates 18 over a time interval to detect the presence of a meal tray, the absence of a meal tray, or the presence of an empty meal tray. Of course, the trolley 1 can be equipped with a different type of detection system 21 to detect the presence or absence of a meal tray in relation to the heating plates, such as the one described, for example, in French patent FR 2 831 682. Each heating plate 18 is connected to a mechanical element in the partition 7 or in the junction area 14, which detects the presence of the tray and activates the heating plate. Inserting the tray into the insulated trolley mechanically activates the heating plates 18.

[0039] Thanks to such a detection system 21, the control unit 23 allows the operation of the heating plates 18 opposite which meal trays with food to be heated are positioned.

[0040] According to an advantageous feature, the control unit 23 is configured to detect the heating plates 18 used to perform the so-called effective reheating of the meal trays. The reheating operation consists of bringing the food in the hot portion of the meal trays (first part 12) to a so-called serving temperature at which the meal tray is ready to be distributed to the end user. However, this reheating operation of a meal tray may be interrupted before completion for various reasons related to the operation of the trolley. Therefore, the control unit 23 detects that a heating plate 18 has performed a reheating operation even if the reheating operation has not yet been completed.

[0041] The control unit 23 thus detects, for each of the heating plates 18, that a reheating operation has taken place—that is, that it is effective—after a predefined operating time or for a predefined temperature value detected by the temperature probe 22. This predefined operating time or temperature value is, of course, less than the value required to reheat the meal tray to its serving temperature. For example, the control unit 23 can be considered to detect, for a heating plate 18, that a reheating operation is effective if the heating plate 18 operates for a heating time of between 2 and 10 minutes.For example, a reheating operation is considered successful if the heating plate 18 operates for 5 minutes, whereas a complete reheating operation lasts approximately 45 minutes. In other words, even if the reheating operation is interrupted before its completion but has exceeded, for example, 5 minutes, the control unit 23 considers that this heating plate 18 has successfully reheated the device.

[0042] It should be noted that the reheating of meal trays can also be considered effective for heating plates 18 reaching a predefined temperature. In other words, as soon as a heating plate 18 reaches a predefined temperature detected by the temperature probe 22, then this heating plate is considered to have effectively reheated the associated meal tray. Of course, it is possible to combine this heating plate temperature criterion with the heating plate operating time criterion to characterize the effective reheating of a meal tray.

[0043] According to another feature of the invention, the control unit 23 is configured to count the number of heating plates 18 used to effectively reheat the meal trays. The control unit 23 thus counts the heating plates 18 that have successfully reheated the meal trays, corresponding, as explained above, to a predefined operating time or to reaching a predefined temperature. This count therefore includes heating plates 18 that have partially reheated the meal trays as well as those that have fully reheated them. Conversely, the control unit 23 does not count heating plates 18 that have been activated for a shorter operating time than the predefined time or that have not reached the predefined temperature.The control unit 23 thus provides information on the number of heating plates 18 used to achieve effective reheating of the meal trays, in accordance with the definition given above.

[0044] It should be noted that the control unit 23 may include a display unit 25 capable of displaying at least the number of heating plates 18 used to effectively reheat the meal trays. According to this embodiment, the trolley 1 is equipped with the control unit 23, whose display unit 25 is mounted in any suitable location to be visible to a trolley user. This display unit 25 may also display the power consumption, for example. Advantageously, the control unit 23 records the number of heating plates 18 used to effectively reheat the meal trays. Typically, the control unit 23 is structured around at least one microcontroller or microprocessor associated with input / output interfaces and memory.

[0045] According to an advantageous embodiment, the control unit 23 includes a communication circuit 26 with a centralized management center 27. The communication circuit 26 informs the centralized management center 27 of at least the number of heating plates 18 used to effectively reheat the meal trays. The communication circuit 26 of the control unit 23 communicates with the centralized management center 27 in any suitable manner, via a wired or wireless connection. For example, the centralized management center 27 is part of a digital network....

[0046] As is evident from the figure 2 This leads to a management system 30 for managing the reheating of meal trays inserted inside at least one insulated transport trolley 1 according to the invention. This management system 30 comprises at least one centralized control unit 27 communicating with the communication circuit 26 of at least one insulated transport trolley 1 for meal trays. Naturally, the centralized control unit 27 communicates with the communication circuits 26 of several insulated transport trolleys 1 for meal trays, together constituting at least one fleet of trolleys operated on a site. The centralized control unit 27 thus receives from each trolley at least the information on the number of heating plates 18 used to effectively reheat the meal trays.

[0047] According to an advantageous embodiment, the centralized management center 27 provides, for each insulated transport trolley, a usage cost based on the number of heating plates 18 used to effectively reheat the meal trays. For example, a unit price is assigned for each use of one heating plate 18.

[0048] The description of the trolley and the installation allows for the implementation of a process to manage the reheating of meal trays 2 which follows directly from the preceding description.

[0049] The method according to the invention aims to detect the heating plates 18 used to reheat meal trays 2 placed inside an insulated transport trolley 1. After activating the heating plates 18 to reheat the meal trays, the method aims to detect which heating plates 18 have been used to effectively reheat the meal trays. The method then aims to count the number of heating plates 18 used to effectively reheat the meal trays.

[0050] According to an advantageous embodiment, the method consists of analyzing the temperature change of the heating plate to detect the presence of a meal tray 2 positioned to be reheated by a heating plate 18. Indeed, it appears that the temperature of the heating plate changes depending on the presence or absence of a meal tray.

[0051] The method aims to analyze the temperature evolution of the heating plate 18 by comparing it with at least one reference temperature evolution of the heating plate. Thus, the temperature evolution of the heating plate 18 is compared with a known temperature evolution of the heating plate, depending on the presence or absence of the meal tray. Typically, the method aims to compare the temperature evolution of the heating plate 18 with: * a reference evolution of the heating plate temperature for which the meal tray is absent, * a reference evolution of the heating plate temperature for which the meal tray is present, * and a reference evolution of the heating plate temperature for which the meal tray does not contain any food to be heated.

[0052] There figure 3 illustrates as an example the reference evolution over time of the temperature of the heating plate 18 in the presence of a meal tray 2 (curve A), in the absence of a meal tray 2 (curve B) and in the presence of an empty meal tray 2, i.e. without food to be heated (curve C).

[0053] Analyzing the temperature evolution of the heating plate 18, i.e. the rate of temperature change of the heating plate, makes it possible to know whether the heating plate is in the presence of a meal tray or an empty meal tray.

[0054] According to the advantageous embodiment implemented, the method aims to control the operation of all the heating plates 18 and to interrupt the operation of any heating plate whose temperature change does not correspond to a reference temperature change for the heating plate containing the meal tray. In other words, as soon as the absence of a meal tray is detected, the operation of the associated heating plate is stopped. Furthermore, it can be provided that as soon as an empty meal tray is detected, the operation of the associated heating plate 18 is stopped.

[0055] It should be noted that the method according to the invention can be implemented with a different system for detecting the presence of the meal trays. According to this alternative embodiment, for each heating plate 18, the presence of a meal tray 2 positioned to be reheated by said heating plate is detected before it is activated, and only the heating plates 18 for which the meal trays 2 are positioned to be reheated are activated.

[0056] According to one feature of the invention, the method consists of detecting the heating plates 18 used to effectively reheat the meal trays. To detect the heating plates 18 used to effectively reheat the meal trays, the method consists of determining which heating plates are in use for a specified duration and / or reach a specified temperature.

[0057] Typically, the process determines which heating plates are used to effectively reheat the meal trays, based on a heating plate operating time of between 2 and 10 minutes. Thus, all heating plates 18 that have operated for this predefined minimum time are considered to have effectively reheated the meal trays.

[0058] Advantageously, the process allows each insulated transport trolley 1 of meal trays to record the number of heating plates 18 used to achieve the effective reheating of the meal trays.

[0059] According to an advantageous feature, the process aims to transmit to a centralized management center 27, the number of heating plates 18 used to achieve the effective reheating of the meal trays.

[0060] The centralized management center 27 determines, based on the number of heating plates 18 used to effectively reheat the meal trays, a cost for using the insulated transport trolley. This cost is then passed on to the trolley operator. It should be noted that this process allows for the rental of such insulated transport trolleys, with the operator being billed based on the number of meal trays actually reheated.

Claims

1. A method for managing the reheating of meal trays (2) inserted inside an isothermal transport trolley (1) for meal trays, the method comprising: * providing at least one isothermal transport trolley (1), comprising a series of stacked heating plates (18) that are each configured to ensure the individual reheating of a meal tray (2) inserted inside the isothermal transport trolley, * controlling the operation of the heating plates (18) to ensure the reheating of the meal trays, * detecting the heating plates (18) used to effectively reheat the meal trays, * and counting the heating plates (18) used to effectively reheat the meal trays.

2. The method according to claim 1, wherein, in order to detect the presence of a meal tray (2) positioned to be reheated by a heating plate (18), the change in temperature over time of the heating plate is analysed.

3. The method according to claim 2, wherein the change in temperature over time of the heating plate (18) is analysed by comparing it with at least one reference change over time of the temperature of the heating plate.

4. The method according to claim 3, wherein the change over time of the temperature of the heating plate (18) is compared with at least: * a reference change over time in the temperature of the heating plate for which the meal tray is absent, * a reference change over time in the temperature of the heating plate for which the meal tray is present, * and a reference change over time in the temperature of the heating plate for which the meal tray does not contain any food to be reheated.

5. The method according to one of claims 1 to 4, wherein the operation of all the heating plates (18) is controlled and the operation of the heating plates is interrupted for each of them for which the change over time in the temperature of the heating plate does not correspond to a reference change over time in the temperature of the heating plate for which the meal tray is present.

6. The method according to claim 1, wherein, for each heating plate (18), the presence of a meal tray positioned to be reheated by the said heating plate is detected before it is controlled in operation, and only the heating plates for which the meal trays (2) are positioned to be reheated are controlled in operation.

7. The method according to one of the preceding claims, wherein, in order to detect the heating plates (18) used to effectively reheat the meal trays, the heating plates used for a specific period of time and / or reaching a specific temperature are determined.

8. The method according to one of the preceding claims, wherein the heating plates used to effectively reheat the meal trays are determined on the basis of an operating time of the heating plate of between 2 and 10 minutes.

9. The method according to one of the preceding claims, wherein each isothermal trolley (1) for transporting meal trays transmits, to a centralised management centre (27), the number of heating plates (18) used to effectively reheat meal trays.

10. The method according to one of the preceding claims, wherein the centralised management centre (27) determines the cost of using the isothermal transport trolley as a function of the number of heating plates (18) used to effectively reheat the meal trays.

11. An isothermal trolley for transporting meal trays, comprising: * an insulating casing (3) internally defining at least one compartment (8) accessible via at least one door (5), * a support structure (11) arranged inside the enclosure to hold meal trays (2) in a stacked position, * a series of individual heating plates (18) for a meal tray held in position by the support structure (11), * a system (20) for managing the reheating of meal trays by the heating plates (18), this system comprising: .a device (21) for detecting, for each heating plate, the presence of a meal tray positioned to be reheated by said heating plate, .a control unit (23) configured to ensure: .. operation of the heating plates (18) to ensure the reheating of the meal trays, .. detection of the heating plates (18) used to effectively reheat the meal trays, .. counting of the heating plates (18) used to effectively reheat the meal trays.

12. The isothermal trolley for transporting meal trays according to the preceding claim comprising, as a device (21) for detecting the presence of a meal tray, a temperature sensor (22) associated with each heating plate (18) and connected to the control unit (23), the control unit (23) analysing the change over time in temperature of the heating plate and comparing it with at least one reference change over time in temperature of the heating plate, with a view to ensuring operation of the heating plates in order to ensure effective reheating of the meal trays, at least for the heating plates provided with a meal tray.

13. The isothermal trolley for transporting meal trays according to one of claims 11 or 12, wherein the control unit (23) delivers information on the number of heating plates used to effectively reheat the meal trays.

14. The isothermal trolley for transporting meal trays according to one of claims 11 to 13, wherein the control unit comprises a communication circuit (26) with a centralised management centre (27).

15. A management facility for managing the reheating of meal trays inserted inside at least one isothermal trolley (1) for transporting meal trays (2) in accordance with one of claims 11 to 14, this facility comprising at least one centralised management centre (27) communicating with the communication circuit (26) of at least one isothermal trolley for transporting meal trays, so as to receive from said trolley at least the information on the number of heating plates used to effectively reheat meal trays.

16. The facility according to the preceding claim, wherein the centralised management centre (27) provides, for each isothermal transport trolley (1), a cost of using the isothermal transport trolley as a function of the number of heating plates (18) used to effectively reheat the meal trays.