Heat stabilization system for hot products and method of manufacturing the same

Abstract

The present invention discloses a thermostabilizing system 100 for the storage and transport of hot goods, particularly food. The system combines a biodegradable polyurethane insulated container 102 with a novel phase change material to achieve improved retention times and temperature ranges. The thermostabilizing system demonstrated in the present invention has achieved retention times of 10-14 hours at temperatures ranging from 45-70°C.

Description

[Technical Field]

[0001] This application claims the benefit of Indian Provisional Patent Application No. 202211065792, filed on November 16, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates generally to supply chain networks, and particularly, but not exclusively, to supply chain networks for the storage and / or transportation of hot goods such as perishable foods. [Background technology]

[0003] Since the pandemic struck the world more than two years ago, demand for food delivery services and platforms has skyrocketed. Currently, 68% of 1,000 consumers surveyed by the National Restaurant Association say they are more likely to order takeout or delivery than they were before the pandemic. For customers, there's nothing worse than paying for a delicious takeout or delivery meal only to have it arrive cold. In a First Orion food delivery survey report, 36% of respondents cited "cold food" as one of the most common issues that required them to contact customer service. Furthermore, delivering hot food while still hot isn't just a customer satisfaction issue—it's also a food safety issue. The FDA states that hot food should be kept at 140°F to prevent bacterial growth. If restaurants are delivering food outside the safe temperature zone, it poses a safety risk to customers.

[0004] Perishable food supply chains (PFSCs) are characterized by increasing concerns over food quality and safety, food waste and losses, and low economic sustainability. Other factors such as power shortages or absence, inadequate infrastructure, and poor connectivity can cause unexpected delays in delivery, resulting in product quality deterioration and spoilage. To mitigate these issues, heat stabilization systems have emerged.

[0005] There are several strategies that can be used when delivering hot food to customers. The first and most obvious is to increase the insulation of the food, for which packaging plays a key role. Choosing the right packaging materials and processes is crucial to ensure the freshness and safety of the product.

[0006] Most commercially available heat-stable systems use an insulated container along with a heating pouch that helps maintain a high temperature within the insulated container. Some commercially available insulated containers utilize insulating materials based on polystyrene, polyethylene, polyvinyl chloride, polypropylene, or polyethylene terephthalate to create a heat-stable container. However, these materials have limitations on disposal and recycling and are not safe for use. For example, expanded polystyrene is a potential carcinogen, and polyvinyl chloride contains chemicals that are harmful to the human body, such as phthalates, lead, cadmium, and organotins.

[0007] Furthermore, most commercially available insulated containers are typically used for low-temperature transportation and catering services. They are inadequate for transporting hot perishable foods over long distances. Efficiently delivering hot foods to customers requires more than just increased insulation. Specific planning involves vehicle characteristics, geographical area-based routing, and delivery prioritization, especially considering the limited period during which these containers can maintain their temperature. Current solutions for storing hot foods include lunch boxes and large insulated catering containers. While these maintain warmth for a short period of time, their large size makes them unsuitable for delivering small orders to customers and too costly for widespread industrial use. Following FDA guidelines, maintaining food at a temperature between 45°C and 70°C is essential to prevent bacterial contamination and food spoilage. Inadequate packaging can lead to bacterial growth within perishable foods, rendering them unsafe and inedible.

[0008] Thus, in the face of increasing demand, it is more important than ever to come up with solutions that provide improved and safer containers for storing and / or transporting hot goods, especially perishable foods such as ready-to-eat meals. Summary of the Invention [Problem to be solved by the invention]

[0009] Herein, the objectives of the present disclosure met by at least one embodiment are listed below.

[0010] The primary object of the present invention is to provide an improved heat stabilization system for the supply chain of hot goods, particularly ready-to-eat foods.

[0011] Another object of the present invention is to improve the holding time of hot goods.

[0012] Another object of the present invention is to provide a wider temperature range for the storage and / or transportation of hot goods.

[0013] It is yet another object of the present invention to provide a cost-effective and sustainable heat stabilization system. [Means for solving the problem]

[0014] The following presents a simplified summary of some embodiments of the invention in order to provide a basic understanding of the invention. This summary is not an extensive overview of the invention, and is not intended to identify key / critical elements of the invention or to outline the scope of the invention. Its sole purpose is to present some embodiments of the invention in a simplified form as a prelude to the more detailed description that is presented later.

[0015] The present invention discloses a thermostabilizing system for the supply chain of hot goods, such as prepared foods. The disclosed thermostabilizing system combines a novel phase change material (PCM)-containing pouch with thermal insulation technology. A phase change material (PCM) is a substance that releases or absorbs sufficient energy during a phase transition to provide useful heat or cooling. The PCM disclosed in the present invention provides a retention time of up to 10 hours in a temperature range of 45-70°C, ideal for preventing microbial growth. This PCM has a latent heat of 100 J / gram and is prepared by simply melt-mixing the required proportion of catechol in glutaric acid at 110°C and then cooling to room temperature to crystallize the mixture. In an exemplary embodiment, 200 grams of PCM was prepared by melting 40 grams of catechol in 160 grams of glutaric acid in a beaker at 110°C and thoroughly mixing. The mixture was cooled and allowed to crystallize. The formed crystals were melted at 80°C and then heat-sealed into kraft polypropylene pouches (CPPs). (The amount of solution required depends on the weight of the food product that needs to be transported; the weight-to-volume ratio should be 5:1.) Kraft polypropylene pouches are selected based on their glass transition temperature, holding capacity, and effective sealing ability. PCM-containing pouches must be preheated at 80°C for 6 hours before use in the proposed heat-stable system.

[0016] Another key component of the disclosed heat-stable system is the insulated container. The material chosen for this container design is polyurethane. Most commercially available insulated containers utilize insulating materials based on polystyrene, polyethylene, polyvinyl chloride, polypropylene, or polyethylene terephthalate to prepare the insulated container. However, these materials have disposal and recycling restrictions and are unsafe for use. For example, expanded polystyrene is a potential carcinogen, and polyvinyl chloride contains chemicals harmful to the human body, such as phthalates, lead, cadmium, and organotin. Thus, polyurethane offers several advantageous characteristics compared to the above materials, making it a suitable material for preparing heat-stable containers. Polyurethane containers are particularly cost-effective to manufacture and maintain in the food delivery industry. Their lightweight construction also makes them suitable for long-distance food transport. Furthermore, polyurethane is biodegradable, environmentally friendly, and does not contain toxic chemicals that disrupt the endocrine system.

[0017] According to a preferred embodiment, polyurethane foam (PUF) is filled between the inner and outer walls of the insulated container, and the container walls are made of aluminum. The thickness of the container can be determined based on the requirements for retention time and temperature range. A container designed with 12 mm thick insulation exhibited a heat transfer efficiency of 378 kJ and provided a retention time of up to 10 hours. Meanwhile, a container designed with 20 mm thick insulation exhibited a heat transfer efficiency of 197.60 kJ and provided a retention time of up to 14 hours.

[0018] In a preferred embodiment, the insulated container is equipped with a heater assembly for externally heating the container, allowing for uniform and consistent heat distribution throughout the material within the container. The heater assembly consists of a heating plate equipped with a nichrome element and is designed to prevent the surface temperature from exceeding 95°C.

[0019] The insulated container further includes a microcontroller-based temperature sensor on the exterior surface of the top lid coupled to a display screen for monitoring and displaying the temperature within the container, the temperature sensor being connected to the microcontroller unit, and the temperature within the container being displayed on the LCD screen.

[0020] In an exemplary embodiment, the insulated container is covered with Rexine cloth to improve aesthetics and ease handling of the container, and the Rexine cloth is adhered to the aluminum container using a 3M adhesive.

[0021] The thermostabilization system according to the present invention achieved a 14-hour hold in the range of 45-70°C.

[0022] The present invention has several use cases, including: · Delivery of cooked meals such as curry and rice; ·Storage and delivery of hot meals for restaurants, railway canteens, cafeterias, etc.; ·Storage utility for travelers, street vendors, hawkers and all stalls in tourist areas; Accessible to remote areas without electricity, ideal for rural areas and beaches. [Brief explanation of the drawings]

[0023] The drawings described herein are for the purpose of illustrating selected embodiments only and are not intended to limit the scope of the present disclosure. The present invention will now be described in conjunction with the following illustrated drawings, in which like numerals refer to like elements. [Figure 1] FIG. 1 is an isometric view of a thermal stabilization system 100 . [Figure 2] FIG. 2 shows the thermostable system 100 in a closed state. [Figure 3] FIG. 3 shows the thermostable system 100 in an open position. [Figure 4] FIG. 4 is an isometric view of the front side of stand 202. [Figure 5] FIG. 5 is an isometric view of the back side of stand 202. [Figure 6] FIG. 6 is a cross-sectional view of the container lid 104. [Figure 7] FIG. 7 is a cross-sectional view of the container base 106. [Figure 8] FIG. 8 is an isometric view of the heater assembly.

[0024] (Detailed explanation) The following detailed description of the invention is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description of the invention.

[0025] In this specification, the term PCM is used to refer to a phase change material prepared by mixing glutaric acid and catechol in a 4:1 ratio, and PCM pouch refers to a kraft polypropylene pouch (CPP) containing the above PCM.

[0026] The terms "insulated vessel" or "hot box" are used interchangeably throughout this specification.

[0027] 1-5, in an exemplary embodiment, Figure 1 shows a proposed thermostability system 100 according to the present invention. The thermostability system 100 generally comprises an insulated container 102 and a PCM pouch.

[0028] The insulated container 102 has a top lid 104 attached to its bottom, the container base 106. The lid 104 is secured to the underside of the container base 106 by a hinge and has a latch 112 on the front for opening and closing. The latch 112 is preferably made of steel and includes a spring for better locking and sturdiness. The hinge is located on the outside of the container 102 for smooth opening and closing. Placing the hinge on the inside of the box makes the lid harder to open and close. The lid 104 has a sensor display screen 108 on its top surface along with a button 110. In this embodiment, the display screen 108 is a 1-inch square LCD screen and the button 110 is a push button.

[0029] In a preferred embodiment, a stand 202 is provided. The stand 202 allows for convenient handling of the hot box and minimizes the possibility of spillage or leakage of the contained products by keeping the box upright. Figures 4 and 5 show isometric views of the front and rear of the stand 202, respectively. In a non-limiting example, the stand 202 is designed from 0.8 mm thick GI metal plate and is mechanically secured to the container base 106 by bolts passing through bolt holes 402.

[0030] Reference is now made to Figures 6 and 7. Figure 6 is a cross-sectional view of the lid 104, and Figure 7 is a cross-sectional view of the container base 106. In a preferred embodiment, the insulated container 102 is designed with outer and inner walls made of 0.8 mm thick aluminum. To provide thermal insulation, polyurethane foam (PUF) is injected between the outer and inner walls of the container 102 through injection holes drilled in the container walls. Reference numerals 602 and 702 indicate the PUF injection areas in the lid 104 and container base 106, respectively.

[0031] The insulated container 102 further includes a heating assembly 800, as shown in FIG. 8. The heating assembly 800 is generally composed of a top plate 802, a bottom plate 806, and a tray 804 housed between the top and bottom plates. The heating assembly 800 is designed to uniformly heat items placed within the sealed insulated container 102. The heating element of the heating assembly is constructed of nichrome. The shape and size of the heating element can be customized based on the shape and size of the insulated container 102. In a preferred embodiment, the heating assembly 800 is designed for a maximum surface temperature of 95°C and includes a circuit breaker that cuts off power to the heater when the current exceeds a certain limit. A microcontroller is also integrated with the heating assembly to regulate the heating of the assembly.

[0032] In the exemplary embodiment, the insulated container 102 is covered with Rexine cloth to enhance aesthetics and facilitate convenient handling of the container. The Rexine cloth is adhered to the aluminum container using a 3M adhesive.

[0033] The technical advantages of the present invention are demonstrated in the form of experimental results shown below:

[0034] The present invention preferably uses polyurethane foam (PUF) as the insulating material in the thermal stabilization system 100 .

[0035] Monitoring the temperature of an insulated container, displayed on the sensor screen 108, has been shown to reduce the risk of food contamination compared to sensors monitoring food temperature. This is because measuring food temperature requires contact between the sensor and the food, which not only presents challenges in sensor placement on the food but can also lead to an unsanitary process. The component placement of the present invention overcomes this drawback.

[0036] By combining a PUF-infused insulated container with a PCM pouch, a temperature range of 45–70°C and a holding time of 10–14 hours were achieved. Various thicknesses of the container and concentrations of the PCM solution were tested to achieve different temperature ranges and holding times.

[0037] In one non-limiting example of the present invention, a 12 mm thick insulated container 102 was tested. The dimensions (length x width x height in centimeters) of the insulated container 102 were set to 20 x 15 x 12 for a thickness of 12 mm.

[0038] In another non-limiting example of the present invention, a 20 mm thick insulated container was tested. The dimensions (length x width x height in centimeters) of the insulated container 102 were 18 x 18 x 18 for the 20 mm thickness.

[0039] The results obtained for the thicknesses tested are as follows: Table 1: Technical specifications for 12mm and 20mm insulated containers [Table 1]

[0040] It has been observed that when the heat stabilization system 100 presented by the present invention is used on food products, the food products maintain their quality without any loss of aroma, taste or texture.

[0041] It has been determined that the manufacturing costs of the containers used in the present invention are lower than other commercially available containers.

[0042] Compared to other commercially available containers made using polystyrene, polyethylene, polyvinyl chloride, polypropylene, or polyethylene terephthalate, the most efficient form of the present invention was observed with polyurethane foam injected into the walls of the insulated container.

[0043] The container's insulation is lightweight and has been found to be readily biodegradable, making it convenient to store, transport and dispose of after use.

[0044] The best results were observed when the PCM was prepared with glutaric acid and catechol in a 4:1 ratio for storage in the desired temperature range.

[0045] While the foregoing detailed description has presented at least one exemplary embodiment, it should be understood that numerous variations exist, and that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as defined in the appended claims and their legal equivalents.

Claims

1. an insulated container (102) for storing or transporting hot goods, wherein the insulating material used for preparing said insulated container (102) is polyurethane foam (PUF); one or more kraft polypropylene pouches containing a phase change material for maintaining a warm temperature within the insulated container (102), the phase change material being a mixture of glutaric acid and catechol; A thermal stabilization system (100) comprising an insulated container (102) and a mechanically configured heating assembly (800) for uniformly heating a product contained within the insulated container (102).

2. The thermostabilization system of claim 1, wherein a temperature range of 45 to 70°C is maintained within the insulated container (102) for a period of 10 to 14 hours.

3. 10. The thermally stable system of claim 1, wherein the phase change material is prepared by mixing glutaric acid and catechol in a ratio of 4:

1.

4. 2. The thermal stabilization system of claim 1, wherein the top lid (104) of the insulated container (102) is secured to the container base (106) by a plurality of hinges, and the lid (104) can be opened and closed using one or more latches (112) provided on the front side of the lid (104) and the container base (106).

5. 2. The thermally stable system of claim 1, wherein the insulated container (102) is designed with a 12 mm thick insulating PUF material and has a heat transfer efficiency of 378 kJ.

6. 2. The thermally stable system of claim 1, wherein the insulated container (102) is designed with a 20 mm thick insulation PUF and has a heat transfer efficiency of 197.60 kJ.

7. 10. A method of storing or transporting hot products utilizing the thermal stabilization system (100) of claim 1, wherein the products include food products.

8. Dissolving 1 part catechol in 4 parts glutaric acid in a beaker at 110°C; Mix thoroughly and cooling the mixture to crystallize; Melting the crystallized mixture at 80°C; and heat sealing the molten crystallized mixture into a kraft polypropylene pouch (CPP).

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