Extreme vacuum cooling with adaptive freezer pressure control for food flavor injection

Abstract

The invention discloses a method and device related to commercial kitchen food processing and preparation. The extreme vacuum cooling (EVC) technology and device are used for food rapid cooling and flavor injection, can operate under the ultra-low pressure condition, and prevents liquid in the refrigerator from splashing through self-adaptive refrigerator pressure control. The EVC cooling and flavor injection device comprises an integrated design suitable for a small load and a dual-module design suitable for a large load. The device can obviously accelerate the pickling and marinating process of food, and saves a large amount of time. By utilizing the EVC device, a large amount of meat, vegetables and fruits can be prepared according to formulas with various flavors. The high-productivity food prefabricated kitchen with the plant as the main part can reduce labor, improve the time efficiency and increase the yield.

Description

Technical Field

[0001] The subject matter of this patent relates to food handling and preparation for commercial kitchens and food processing plants. More specifically, this patent relates to methods and apparatus for rapid cooling and flavor infusion of food. Background Art

[0002] In U.S. Patent Application No. 17,469,712 (the entire contents of which are hereby incorporated by reference), we disclose a method and apparatus for extreme vacuum cooling (EVC), wherein an EVC cooler operates at ultra-low pressure conditions, has adaptive pressure control, can process large quantities of food, meet government food safety regulations, save energy and time, and achieve uniform cooling to maintain good food quality. Extreme vacuum cooling (EVC) technology is defined as vacuum cooling at extremely low pressure conditions with vacuum cabinet pressure control and added clean dry air or inert gas.

[0003] Vacuum cooling is based on the principle of evaporative cooling, where water absorbs a large amount of heat in order to evaporate from a liquid to a gas. Water evaporation can occur at any temperature above freezing. When the freezer pressure of an EVC unit is intentionally reduced, the vapor pressure of the water inside the food can become higher than the freezer pressure, causing the water inside the food to quickly convert to vapor. This water evaporation transfers energy to cool the food evenly throughout the food mass. The conversion of water to vapor can occur quickly so that the resulting energy transfer can cool the food evenly and quickly.

[0004] However, if the pressure difference between the freezer pressure and the vapor pressure of the water inside the food is too high, excessive foaming may occur due to rapid evaporation. When the bubbles burst on the surface of the food, the force of the bubble surface tension may cause splashing inside the freezer. This is not a problem for solid foods, such as beef and chicken, because the food structure does not fall apart when the steam passes through the food into the vacuum freezer. For low viscosity foods, such as soups and sauces, this can be a big problem. We call this a liquid splash event for these low viscosity foods.

[0005] In U.S. Patent Application No. 17,469,712, solid foods with high viscosity are defined as Type A foods and liquid foods with low viscosity are defined as Type B foods. For example, Type A foods include beef, pork, chicken, potatoes, baked foods, and stir-fried meats and vegetables. Type B foods include soups, stews, sauces, and pasta in sauces. There may be a gray area between what is actually Type A or Type B food. In any case, viscosity is used in food cooling recipes and freezer pressure set point calculations to ensure that the EVC device can cool all types of food with good and consistent performance.

[0006] Liquid splash events can contaminate food freezers when interior freezer surfaces and shelf fixtures are coated with food liquids and sauces. It is important to carefully control freezer pressure for Type B foods so that the pressure differential between freezer pressure and vapor pressure is properly and automatically managed to achieve rapid cooling and avoid liquid splash.

[0007] In recent years, the culinary industry has been advocating the concept of plant-based. It is a cooking and eating style that emphasizes the consumption of foods from plants, including fruits and vegetables, whole grains, legumes, nuts and seeds, vegetable oils, and herbs and spices, aiming to promote health and support the sustainability of the earth. Although a small amount of meat can still be added to "plant-based" dishes, this new type of plant-based dishes needs to have richer flavors to attract consumers.

[0008] In commercial kitchens, chefs and workers need to prepare a large amount of food within a certain period of time. In order to give the food more and better flavor, they usually marinate and stew meat and vegetables before cooking. However, it may take hours to days to marinate or stew food using conventional methods. This may become a major bottleneck in commercial kitchens. Therefore, it is very necessary to provide a food flavor injection device that enables chefs to prepare a large amount of food in a shorter time.

[0009] Various attempts have been made to speed up the pickling process. For example, vacuum picklers for home use, such as those described in U.S. Pat. No. 7,047,875, include models ranging from simple sealed containers to those that use a hand-operated pump to extract air. In addition, vacuum drums, such as those described in U.S. Pat. No. 5,230,221, can also play a role in improving the food pickling process.

[0010] While these devices can potentially improve marinating to some extent, they have key disadvantages and are not suitable for food flavor infusion in commercial kitchens. Reasons include the following: (1) These devices can only produce vacuum conditions slightly below the ambient atmospheric pressure. Therefore, the time savings due to the vacuum are very small. (2) These devices usually operate at room temperature. If flavor infusion cannot be completed within the 4-hour food safety regulation time period, it may cause food safety issues. (3) Food vacuum tumblers can damage food during their tumbling operation, which can compromise product quality. (4) Home marinating machines can only process small amounts of food.

[0011] On the other hand, there are vacuum coolers used in agriculture and food processing, such as vacuum coolers for cooling baked products. However, these vacuum cooling devices cannot be used for food flavor injection. They do not have the ability to deal with the problem of liquid splash. Since food flavor injection requires the food to be immersed in marinade or brine, the problem of liquid splash is the main technical obstacle for vacuum cooling devices to be used for food flavor injection. Summary of the invention

[0012] In this patent, we describe extreme vacuum cooling (EVC) technology and devices for food flavor infusion. The EVC device can operate at ultra-low pressure conditions, such as 1kPa or 99% vacuum conditions, to achieve more efficient use of time and energy for rapid cooling and flavor infusion. By implementing adaptive pressure control on the food freezer, liquid splashing can be avoided, allowing the EVC device to be efficiently used for rapid food cooling and flavor infusion, saving a lot of time. Using the EVC food flavor infusion device, a large amount of meat, vegetables and fruits can be marinated or braised with various flavor infusion recipes.

[0013] We conducted a variety of brining and pickling tests on meats and vegetables to quantify the performance of the EVC Food Flavor Infusion Device at 0.01 ATM and compared it to the same ingredients processed using traditional methods at atmospheric pressure conditions. The effectiveness of flavor infusion was quantified by the weight gain of the tested ingredients. In one case, the weight gain of the test meat was recorded after 4 hours of brining in each test using the EVC device. Subsequently, the same type and amount of meat was brined using traditional methods at atmospheric pressure conditions. When the weight gain reached the same level, the brining time required was recorded. Our test results show that the time savings for food flavor infusion using the EVC device are significant. The time required for brining or pickling is typically only one-half to one-third of that required for traditional methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In the attached figure:

[0015] Figure 1 A perspective view of a unitized design EVC cooling and food flavor infusion device is shown, according to one embodiment of the present invention.

[0016] Figure 2 A perspective view of a unitized design of an EVC cooling and food flavor infusion device is shown, showing more of its components, according to one embodiment of the present invention.

[0017] Figure 3 A perspective view of a modular design EVC cooling and food flavor infusion device showing all major components and a refrigerator pressure control system according to one embodiment of the present invention is shown.

[0018] Figure 4 is a perspective view of an EVC cooling and food flavor infusion device having a dual module design including a food cooler module and a utility module according to an embodiment of the present invention.

[0019] Figure 5is a perspective front view of a food cooler module having key components for EVC cooling and food flavor infusion apparatus according to an embodiment of the present invention.

[0020] Figure 6 is a perspective view of a utility module having key components for an EVC cooling and food flavor infusion device according to an embodiment of the present invention.

[0021] Figure 7 is a perspective view of an EVC cooling and food flavor infusion device having a dual module design showing all major components with a freezer pressure control system according to an embodiment of the present invention.

[0022] Figure 8 is a diagram of a 2-input-1-output (2x1) pressure control system for controlling cabinet pressure of an EVC cooling and food flavor infusion device according to an embodiment of the present invention.

[0023] Fig. 9 : is a diagram showing the mechanism of a reverse split range setter according to an embodiment of the present invention, which can divide a controller signal into 2 ranges to operate a vacuum control valve and an inflow air control valve.

[0024] Fig.10 is a time-amplitude graph illustrating a freezer pressure set point trajectory for cooling high viscosity foods, controlled freezer pressure, boiling temperature, and food temperature, in accordance with an embodiment of the present invention.

[0025] Fig.11 is a time-amplitude graph illustrating freezer pressure set point trajectories for cooling low viscosity foods and for food flavor infusion as well as boiling point temperature and food temperature in accordance with an embodiment of the present invention.

[0026] Fig.12 is a diagram showing a method for using the Figures 1 to 8 A block diagram of the steps of a method for marinating or braising food using an EVC food flavor injection device is shown.

[0027] The term mechanism is used herein to refer to hardware, software, or any combination thereof. The term EVC refers to extreme vacuum cooling as defined and described in this patent application. The terms EVC cooling and food flavor infusion apparatus refer to the extreme vacuum cooling device introduced in this patent. The term HMI refers to a human-machine interface including a computer screen to allow a user to interact with the device. The term IPC refers to an industrial personal computer. The term PLC refers to a programmable logic controller. The term PAC refers to a programmable automation controller.

[0028] In this patent, we define solid foods with high viscosity as type A foods and liquid foods with low viscosity as type B foods. For example, type A foods include beef, pork, chicken, potatoes, baked foods, and stir-fried meat and vegetables. Type B foods include marinades, brine, brine, wine, juice, oil, soup, stew, sauce, and pasta in sauce.

[0029] Without loss of generality, all numerical values ​​given in this patent are examples. Other values ​​may be used without departing from the spirit or scope of the present invention. The description of specific embodiments herein is for the purpose of demonstration and is by no means intended to limit the scope of the present disclosure to exclude other embodiments of the present invention that are not particularly described. DETAILED DESCRIPTION

[0030] A. Extreme Vacuum Cooling for Food Flavor Infusion

[0031] Figures 1 to 11 An extreme vacuum cooling (EVC) device with two design embodiments having adaptive cabinet pressure control for rapid food cooling and flavor infusion is shown in FIG.

[0032] Figure 1 A perspective view of a unitized design EVC cooling and food flavor injection device is shown, according to one embodiment of the present invention. The EVC cooling and food flavor injection device 10 includes a food refrigerator 12, a refrigerator door 14, a trolley 16 that is pushed into the food refrigerator, a food tray 18 on the trolley, an instrument panel 20, a left front panel 22, a control and monitoring computer 24 with an HMI screen, and a system power switch 26.

[0033] The food freezer 12 is constructed so that it can operate under extremely low pressure conditions. In this embodiment, the extremely low pressure condition can be defined as less than or equal to about 0.1 ATM or 10kPa. The freezer door 14 allows the user to easily access the interior of the food freezer and can isolate the freezer from atmospheric pressure. Because the device can operate under extremely low pressure conditions, the food freezer and its door are specially designed and manufactured to cope with the pressure difference between atmospheric pressure and 0 Pascal (vacuum pressure), which is approximately 100 kPa. The food tray trolley 16 is constructed of stainless steel and has multiple brackets to hold food trays or trays. Foods such as meat, vegetables, noodles and soup are placed in the food tray 18. The dashboard 20 includes sensors, inlet air control valves and air filters, electrical wires and signal lines. The left front panel 22 covers the pressure that will be Figure 2 The main components of the device described in . A control and monitoring computer 24 with an HMI screen is mounted on the left front panel and can provide cabinet pressure control and logic control for the EVC device. The human machine interface (HMI) screen allows the user to operate the device. The system power switch 26 can turn the device on and off.

[0034] In this embodiment, the EVC device adopts an integrated design, integrating all components into one device. This simplified design is suitable for rapid cooling and food flavor injection applications with a small total load (e.g., less than 100 pounds).

[0035] Figure 2 A perspective view of an EVC cooling and food flavor infusion device of a unitized design is shown, showing more of its components according to one embodiment of the present invention. The EVC cooling and food flavor infusion device 10 includes a food cooler 12, a cart 16 that rolls within the food cooler, a food tray 18 on the cart, an instrument panel 20, a cold trap 32, a vacuum pump 34, a vacuum control valve 36, an outflow air outlet 33, a refrigeration unit 35, and an electrical panel 38.

[0036] exist Figure 2 Components 12, 16 and 18 are already in Figure 1 . The cold trap 32 is used to condense water vapor from the food refrigerator back into liquid form. The vacuum pump 34 can pump air out of the food refrigerator to achieve an extremely low pressure condition. The vacuum control valve 36 is used to isolate the cold trap 32 and the food refrigerator 12. When the vacuum pump 34 is running to pump air out of the food refrigerator, the valve can also regulate the outflow air. Therefore, it is used as one of the actuators to control the refrigerator pressure. The refrigeration unit 35 is used to cool the cold trap 32 to condense water vapor. The outflow air outlet 33 allows air to be pumped out to the atmosphere. The electrical panel 38 is used to receive power and supply power to the EVC device.

[0037] Figure 3 A perspective view of a modular design EVC cooling and food flavor infusion device is shown, showing all major components and a refrigerator pressure control system according to one embodiment of the present invention. The EVC cooling and food flavor infusion device 10 includes a food refrigerator 12, a trolley 16 that is pushed into the food refrigerator, a food tray 18 on the trolley, an instrument panel 20, a cold trap 32, a vacuum pump 34, a vacuum control valve 36, an outflow air outlet 33, a refrigeration unit 35, an electrical panel 38, an inline air filter 41, an inflow air control valve 42, an inflow air inlet 43, a temperature sensor 44, a humidity sensor 46, a pressure sensor 48, and a 1-input-2-output controller 40.

[0038] exist Figure 3 In, already in Figure 1 and Figure 2 Components 12, 16, 18, 32, 33, 34, 35, 36 and 38 are described in detail. Temperature sensor 44, humidity sensor 46 and pressure sensor 48 are Figure 1 and Figure 2The actual sensor probes are installed at different locations within the food refrigerator. For example, there may be multiple temperature sensor probes that are inserted into food samples in different food trays to measure the food temperature. Humidity sensor probes and pressure sensor probes are usually installed at the top of the food refrigerator.

[0039] exist Figure 3 In, a 1-input-2-output controller 40 can provide adaptive freezer pressure control for a food freezer. To avoid liquid splashing, it is important to control the freezer pressure based on a predetermined pressure set point trajectory that is derived based on food type, viscosity, freezer pressure, food temperature, and boiling temperature. For food flavor infusion, the food is immersed in a marinade or brine, which typically has a low viscosity. The freezer pressure set point trajectory for marinating should be determined based on the viscosity of the brine, and the pressure set point trajectory for pickling should be derived based on the viscosity of the specific marinade. In Figures 8 to 11 The freezer pressure control system is described in more detail in.

[0040] Figure 4 is a perspective view of an EVC cooling and food flavor infusion device having a dual module design including a food cooler module and a utility module according to an embodiment of the present invention.

[0041] The EVC cooling and food flavor infusion device 50 includes a food refrigerator 52, a refrigerator door 54, a trolley 56 pushed into the food refrigerator, a food tray 58 on the trolley, an instrument panel 59, a utility module 60, a cold trap 62, a vacuum pump 64, a vacuum control valve 66, an outflow air outlet 63, a refrigeration unit 65, an electrical panel 68, a vacuum air connection pipe and connector 67, electrical and signal line conduits 69, and a control and monitoring module 70.

[0042] and Figures 1 to 3 Compared to the unitized design EVC unit in the Refrigerator, this is a dual-module design that separates the food cooler from the utility module. This design is suitable for rapid cooling and food flavor infusion applications with a large total load, such as a total load between 100 and 300 pounds. The dual-module design has many advantages, such as the food cooler and utility module can be limited to a certain size and weight range, which is easy to transport and install.

[0043] exist Figure 4In the embodiment, the food refrigerator 52 is constructed so that it can work under extremely low pressure conditions. In this embodiment, the extremely low pressure condition can be defined as less than or equal to about 0.1 ATM or 10kPa. The refrigerator door 54 allows the user to easily access the interior of the food refrigerator and can seal the food refrigerator from atmospheric pressure. Because the device can operate under extremely low pressure conditions, the food refrigerator and its door are specially designed and manufactured to cope with the pressure difference between atmospheric pressure and 0 Pascal (vacuum pressure), which is about 100 kPa. The food tray trolley 56 is constructed of stainless steel and has multiple brackets to hold food trays or trays. Foods such as meat, vegetables, noodles, soup, etc. are placed in the food tray 58. The dashboard 59 includes sensors, inflow air control valves, wires and signal lines.

[0044] Inside the utility module 60, a cold trap 62 is used to condense water vapor from the food freezer back into liquid form. A vacuum pump 64 can pump air out of the food freezer to achieve an extremely low pressure condition. A vacuum control valve 66 is used to isolate the cold trap 62 and the food freezer 52. In addition, when the vacuum pump 64 is running to pump air out of the food freezer, the valve can regulate the outflow air. Therefore, it is used as one of the actuators to control the freezer pressure. A refrigeration unit 65 is used to cool the cold trap 62 to condense water vapor. An outflow air outlet 63 allows air to be pumped out to the atmosphere. A vacuum air tube and connector 67 can connect the food freezer and the cold trap so that air can be pumped out of the food freezer through the cold trap. An electrical wire and signal wire conduit 69 accommodates electrical wires and signal wires between the food freezer and the utility module. A control and monitoring module 70 can be attached to the food freezer using a bracket mount.

[0045] Figure 5 1 is a perspective front view of a food cooler module with key components for EVC cooling and food flavor injection devices according to an embodiment of the present invention. The food cooler module 51 includes a food cooler 52, a trolley 56 pushed into the food cooler, a food tray 58 on the trolley, an inflow air inlet 53, an instrument panel 59, a vacuum air connection pipe and connector 67, an electrical wire and signal wire conduit 69, a control and monitoring module 70, a control and monitoring computer 72 with an HMI screen, a system power switch 74, and a system status light 76.

[0046] Parts 52, 56, 58, 59, 67 and 69 are already in Figure 4. The inlet air inlet allows air to flow within the food refrigerator to return the refrigerator pressure to atmospheric pressure. Inlet air is also important in refrigerator pressure control when it is necessary to increase the refrigerator pressure by adding clean air to the refrigerator to avoid liquid splash events. A control and monitoring computer 72 with an HMI screen can provide refrigerator pressure control and logic control for the device, and a human-machine interface (HMI) screen allows a user to operate the device. The control and monitoring computer with an HMI screen can be implemented with a number of options, including: (a) an industrial personal computer (PC) with a Windows or Linux operating system, (b) a programmable logic controller (PLC), (c) a programmable automation controller (PAC), (d) a specially designed control device, and (e) a combination thereof.

[0047] The system power switch 74 can turn the power of the device on or off. The system status light 76 can be designed with three lights. For example, (a) a flashing green light indicates that the device is in normal operation, that is, when the refrigerator pressure is at or below atmospheric pressure; (b) a flashing orange light indicates that the refrigerator door is open and the system is not ready to start vacuum operation; and (c) a flashing red light indicates that the system has an error or needs human attention.

[0048] Figure 6 6 is a perspective view of a utility module with key components for an EVC cooling and food flavor infusion device according to an embodiment of the present invention. The utility module 60 includes a cold trap 62, a vacuum pump 64, an outflow air outlet 63, a vacuum control valve 66, a refrigeration unit 65, an electrical panel 68, a vacuum air connection pipe and connector 67, and electrical and signal line conduits 69.

[0049] exist Figure 6 In the example, components 62, 64, 65, 66, 67 and 69 are already Figure 4 . The outflow air outlet 63 is connected to a vacuum pump 64 and allows air to flow out to the atmosphere. The electrical panel 68 can receive power and supply power to operate the device. Since the device is targeted at the global market, it can support different electrical standards in the world. Therefore, the device can be designed to obtain three-phase AC power or single-phase AC power from the local power grid.

[0050] Figure 78 is a perspective view of an EVC cooling and food flavor injection device with a dual module design according to an embodiment of the present invention, which shows all major components with a refrigerator pressure control system. The EVC cooling and food flavor injection device 80 includes a food refrigerator module 51, a utility module 60, and a control and monitoring module 70. Within these three major modules, the device 80 also includes: a food refrigerator 52, a trolley 56 pushed into the food refrigerator, a food tray 58 on the trolley, a cold trap 62, a vacuum pump 64, a refrigeration unit 65, a vacuum control valve 66, an electrical panel 68, a vacuum air connection pipe and connector 67, an electrical wire and signal wire conduit 69, an inflow air control valve 82, an inline air filter 81, an inflow air inlet 83, a temperature sensor 84, a humidity sensor 86, a pressure sensor 88, and a 1-input-2-output controller 89.

[0051] Parts 52, 56, 58, 62, 64, 65, 66, 67, 68 and 69 are already in Figures 4 to 6 . The vacuum control valve 66 is used to isolate the cold trap 62 and the food freezer 52, and can regulate the outflow air when the vacuum pump 64 is running to pump air out of the food freezer. Therefore, it is used as one of the actuators to control the freezer pressure. The inflow air control valve 82 can regulate the inflow air flow rate so that it is used as another actuator for freezer pressure control. The inflow air control valve 82 can also be used as a vent valve. When it is fully opened, air can freely enter the food freezer so that the freezer pressure can return to atmospheric pressure. This is an important step before opening the freezer door to remove the trolley and food trays. The inline air filter 81 is used to filter the inflow air so that the inflow air is clean for the food freezer. The inflow air inlet 83 allows air to enter the food freezer through the inflow air control valve 82.

[0052] exist Figure 7 In the system, temperature sensor, humidity sensor and pressure sensor are Figure 4 and Figure 5 The actual sensor probes are installed at different locations within the food refrigerator. For example, there may be multiple temperature sensor probes that are inserted into food samples in different food trays to measure the food temperature. Humidity sensor probes and pressure sensor probes are usually installed at the top of the food refrigerator.

[0053] exist Figure 7In, a 1-input-2-output controller 89 can provide adaptive pressure control for a food freezer. To avoid liquid splashing, it is important to control the freezer pressure based on a predetermined pressure set point trajectory that is derived based on food type, viscosity, freezer pressure, food temperature, and boiling temperature. For food flavor infusion, the food is immersed in a marinade or brine, which typically has a low viscosity. The freezer pressure set point trajectory for marinating should be determined based on the viscosity of the brine, and the pressure set point trajectory for pickling should be derived based on the viscosity of the specific marinade. In Figure 8 and Fig. 9 The freezer pressure control system is described in more detail in.

[0054] B. Adaptive Freezer Pressure Control for EVC Devices

[0055] Figure 8 1 is a diagram of a 2-input-1-output (2x1) pressure control system for controlling the cabinet pressure of an EVC cooling and food flavor injection device according to an embodiment of the present invention. The 2-input-1-output (2x1) pressure control system 90 includes a 1-input-2-output (1x2) controller 92, a 2-input-1-output (2x1) system 94, an actuator A1 96, an actuator A2 98, signal adders 100, 102, and a set point trajectory calculation mechanism 104. Figure 8 The signals shown are as follows: r(t) - set point. y(t) - measured variable or process variable, y(t)=x(t)+d(t). x(t) - System output. V1(t) - Controller output 1, used to operate actuator A1. V2(t) - Controller output 2, used to operate actuator A2. d(t) - disturbance, caused by noise or load changes. e(t) - Error between the set point and the measured variable, e(t)=r(t)-y(t).

[0056] The control objective is for the controller to generate outputs V1(t) and V2(t) to manipulate actuators A1 and A2 so that the measured variable y(t) tracks a given trajectory of its set point r(t) under set points, disturbances, and process dynamics. In other words, the controller's task is to minimize the error e(t) in real time.

[0057] When using traditional control methods, automatic control of the cold cabinet pressure of an EVC device can be a challenge. We must control the cold cabinet pressure based on a varying pressure setpoint trajectory. In addition, the same pressure control system must cope with varying food types, payload variations, and other uncertainties. Fundamentally, a 1x2 pressure controller has only 1 input, i.e., the control error e(t), but must produce 2 control outputs V1(t) and V2(t) to simultaneously manipulate 2 actuators, namely the vacuum control valve and the incoming air control valve.

[0058] In U.S. Patent 7,142,626, “Apparatus and method of controlling multi-input-single-output systems” (控制多输入-单输出系统的装置和方法), a 2-input-1-output (2x1) model-free adaptive (MFA) control system is described. The model-free adaptive (MFA) control technology described in U.S. Patents 7,142,626, 6,055,524, and 6,556,980 is an artificial intelligence (AI) technology that uses an artificial neural network (ANN) as a key component of the controller. Adaptive cold cabinet pressure control using the model-free adaptive (MFA) control technology has been described in U.S. Patent Application No. 17,469,712.

[0059] Fig. 9 is a view according to an embodiment of the present invention, illustrating the mechanism of a reverse split-range setter that can split a controller signal into 2 ranges to manipulate a vacuum control valve and an incoming air control valve.

[0060] By separately moving and setting knobs R1 and R2 110, the controller outputs V1(t) and V2(t) are calculated according to the following formulas implemented in the split-range setter mechanism 110: where 0 < R1 ≤ 100, which defines the u(t) split-range of the controller output V1(t); and where 0 ≤ R2 < 100, which defines the u(t) split-range of the controller output V2(t). The signals u(t), V1(t), and V2(t) all have a working range of 0% to 100%. In this design, the control valve is cut off at 0% in its closed position. We can freely move and set the R1 and R2 knobs within their (0, 100) range to produce the controller outputs V1(t) and V2(t), where there may be dead zones or overlaps, or no gaps in between.

[0061] In the cold cabinet pressure control of an EVC device, there are 3 operating conditions: (1) The vacuum control valve is opened, the inflow air flow valve is closed, and the cold cabinet pressure decreases; (2) Both the vacuum control valve and the inflow air control valve are closed, and the cold cabinet pressure remains stable; and; (3) The vacuum control valve is closed, the inflow air flow valve is opened, and the cold cabinet pressure increases.

[0062] Thus, we can move and set the R1 and R2 knobs to obtain sufficient dead zones to support all three operating conditions. For example, we can set R1 = 40 and R2 = 60. When u(t) < 40, the vacuum control valve is opened to remove air from the cold cabinet, causing the cold cabinet pressure to decrease. In the dead zone, where 40 < u(t) < 60, V1(t) = V2(t) = 0 forces both control valves to close. When u(t) > 60, the inflow air control valve is opened. The inflow of clean air into the cold cabinet causes the pressure to increase.

[0063] U.S. Patent 7,142,626 also describes a 2x1 PID (Proportional Integral Derivative) control system, which can potentially be used for the cold cabinet pressure control of the EVC device. When the derivative action is removed from the PID controller, it becomes a PI controller. When the integral action is removed from the PI controller, it becomes a P controller. Although the performance of the PI and P controllers will not be as good as that of the MFA controller, both the PI and P controllers can potentially be used for cold cabinet pressure control.

[0064] C. Design of the Cold Cabinet Pressure Setpoint Trajectory for Flavor Injection

[0065] As defined in the opening section of this specification, extreme vacuum cooling (EVC) is vacuum cooling carried out under extreme low-pressure conditions through vacuum cold cabinet pressure control and the addition of clean dry air or inert gas. The EVC device disclosed in this patent can marinate or braise meat, vegetables, and fruits.

[0066] For the EVC device, dealing with the potential liquid splash problem during the processing of Class B foods and the flavor injection process is a major challenge. When the pressure difference between the pressure inside the cold cabinet and the vapor pressure of the water inside the food is too large, excessive bubbles may be generated due to rapid evaporation. For low-viscosity foods (such as soups and sauces) and in the case of flavor injection using brine or marinade, the liquid splash problem is the main obstacle faced by users. Therefore, for Class B foods and the flavor injection process, the cold cabinet pressure must be precisely controlled to ensure that the pressure difference between the cold cabinet pressure and the vapor pressure can be properly and automatically managed to achieve rapid cooling while avoiding liquid splash events.

[0067] Fig.101 is a time-amplitude diagram showing a cabinet pressure set point trajectory for cooling high viscosity food, controlled cabinet pressure, boiling temperature, and food temperature according to an embodiment of the present invention. The diagram includes trends of pressure set point Ps 112, cabinet pressure Pc 114, boiling temperature Tbp 116, and food temperature Tf 118.

[0068] Since liquid splashing does not occur with Type A food, we can reduce the vacuum pressure more aggressively based on the capabilities of the EVC device. For example, the vacuum pressure set point Ps 112 can be designed to vary from atmospheric pressure (1.0 ATM or 100 KPa) to extreme low pressure (0.01 ATM or approximately 1.0 KPa) to achieve rapid vacuum cooling. The freezer pressure Pc 114 can be controlled to track its set point Ps. In this case, the 1x2 pressure controller described in Part B of this article will operate within its OP range between 0 and 40 to manipulate the vacuum control valve and achieve pressure control while the inflow air control valve is in the closed state.

[0069] The boiling point of a substance is the temperature at which a liquid turns into a gas when its vapor pressure equals the pressure around it. Therefore, in a vacuum freezer, the boiling point temperature of the water inside the food is directly related to the freezer pressure. It can be seen that the boiling point temperature of the water inside the food Tbp 116 varies with the freezer pressure Pc 114. The food inside the freezer is gradually cooled and its temperature is measured by a temperature sensor to produce a food temperature Tf. It should be noted that there is a time lag between Tbp 116 and Tf 118. For type A food, this temperature difference is not a problem.

[0070] For type A food, the freezer pressure set point trajectory can be based on Fig.10 The following formula is shown:

[0071] In these formulas, Pi(0) is the initial value of the freezer pressure, the constant a is the slope of the pressure ramp down, and the constant C is the pressure set point for the EVC unit operating at a fixed vacuum pressure. The actual values ​​of the slope and constants depend on the EVC unit capacity, food viscosity, total weight, and the difference between the boiling temperature and the food temperature. They can be derived experimentally and stored in the recipe as predetermined values. Note that for type B food, if we base Fig.10 If the EVC device is operated with the pressure set point trajectory shown in , the large temperature difference between Tbp and Tf can cause liquid splashing.

[0072] Fig.11 is a time-amplitude graph showing freezer pressure set point trajectories for cooling low viscosity foods and for food flavor infusion as well as boiling point temperature and food temperature in accordance with an embodiment of the present invention.

[0073] As explained in the opening section of this document, if the pressure differential between the freezer pressure and the vapor pressure of the water inside the food is too high, excessive foaming may occur due to rapid evaporation. When the bubbles collapse at the food surface, the force of the bubble surface tension can cause liquid splashing inside the freezer of Type B foods. For Type B foods and food flavor infusion, precise control of the freezer pressure is critical to ensure that the pressure differential between the freezer pressure and the vapor pressure is properly managed, allowing the EVC device to achieve rapid cooling or flavor infusion while avoiding liquid splashing events.

[0074] Since the boiling point temperature has a direct relationship with the freezer pressure, we can also use a constraint based on the difference between the boiling point temperature and the food temperature to control the freezer pressure to avoid liquid splashing for type B food. Fig.11 As shown, the freezer pressure set point Ps 120 can be reduced at the beginning to give the start of vacuum cooling. In this figure, the measured freezer pressure is not shown, but it should track the pressure set point. In this case, we can assume that the freezer pressure is equal to the pressure set point. The boiling temperature Tbp 122 decreases as the freezer pressure decreases. Thereafter, we can intentionally maintain the pressure for a period of time, then increase the freezer pressure by closing the vacuum control valve, and add clean dry air to the freezer to reach the pressure level and wait at this pressure level before the food temperature Tf 124 starts to decrease. The purpose of adding clean air is to increase the freezer pressure and maintain the temperature difference between Tbp and Tf so that liquid splashing does not occur.

[0075] like Fig.11 As shown in Figure 1, the freezer pressure set point trajectory can be calculated based on vapor pressure, boiling temperature and viscosity. The formulas used in this example to calculate vapor pressure and boiling temperature related to viscosity are known techniques described in "Perry's Chemical Engineers' Handbook" (authors Don Green and Marylee Z. Southard, published by McGraw-Hill Education), which book and its contents are expressly incorporated by reference herein.

[0076] Without loss of generality, we can design the refrigerator pressure set point Ps(t) for cooling type B food and for food flavor injection based on the following formula, which is Fig.11 It shows:

[0077] In these formulas, Pi(0) is the initial value of the freezer pressure and the constants a, b, and d are the slopes of the pressure ramp down, ramp up, and final ramp down. The constants C1, C2, and C3 are the pressure set points for the EVC unit operating at a fixed vacuum pressure. The actual values ​​of these slopes and constants are related to the EVC unit capacity, food viscosity, total weight, and the difference between the boiling temperature and the food temperature. They can be derived experimentally and stored as predetermined values ​​in the cooling or flavor infusion recipe. When conducting experiments, a visco analyzer can be used to measure the food or marinade viscosity.

[0078] For food flavor infusion, marinating is often done using a brine. Marinades can include soy sauce, teriyaki sauce, buttermilk, yogurt, ketchup, wine, liquor, vinegar, papaya juice, orange juice, kiwi juice, pineapple juice, apple juice, olive oil, brine, or a combination of these ingredients. The viscosity of marinades can vary greatly. The cooler pressure set point trajectory for marinating can be derived through certain formulas and experiments and saved in a computer database. When using an EVC cooling and flavor marinating device, the user can retrieve the trajectory as part of a marinating or marinating recipe.

[0079] D. Extreme Vacuum Cooling Methods for Food Flavor Infusion

[0080] Fig.12 is a diagram showing a method for using the Figures 1 to 11 A block diagram of the steps of a method for marinating or braising food using an EVC food flavor injection device is shown.

[0081] The food flavor injection step begins at box 130, where meat, vegetables and fruits are soaked in a food pan covered with a marinade or brine. At box 132, the food pan with the food for marinating or pickling is placed in the food refrigerator of the EVC device. In addition, multiple temperature sensor probes are inserted into the food sample for food temperature measurement. The average value of the temperature can be used as the food temperature Tf for temperature monitoring and calculation of the refrigerator pressure set point trajectory described in Section C of this article.

[0082] At box 134, the operator closes the freezer door and then logs into the control and monitoring computer with the HMI screen. At box 136, a food flavor infusion recipe is selected from a recipe selection menu associated with the type of brine or marinade and the total weight of the food in the freezer. The freezer pressure set point trajectory calculation is associated with food type A or B or Fig.10 and Fig.11 The types of marinades shown are very relevant.

[0083] At box 138, the operator begins the food flavor injection process, and the cabinet pressure is controlled according to a pre-set pressure trajectory. At box 140, the operator waits for a predetermined time. At box 142, the marinating or pickling process is completed and the food cabinet pressure is restored to atmospheric pressure. The food tray is then removed from the food cabinet.

[0084] E. Conclusion

[0085] Our motivation for developing Extreme Vacuum Cooling (EVC) technology and products is in line with the general trend of food industry transformation. Similar to semiconductor foundries or wafer fabs, food foundries are modern commercial kitchens or food processing plants that can produce large quantities of small packages of specially formulated foods to serve specialized customers or target customer groups. In food foundries, large quantities of food need to be cooked and refrigerated for future consumption.

[0086] In commercial kitchens, chefs and workers need to prepare a large amount of food within a certain period of time. In order to make the food have a better and more unique taste, they usually pickle and stew meat and vegetables before cooking. However, pickling or stewing food using conventional methods may take hours to days, which may become a major bottleneck in commercial kitchens. The stewed or pickled food still needs to be placed in a cooling environment to meet food safety standards. Therefore, it is desirable to provide a food flavor injection device that enables chefs to pickle, cook and cool a large amount of food in a shorter time.

[0087] The main objectives of the present invention are to rapidly cool the food to remove the cooked food from the danger zone, meet food safety standards, and effectively preserve the food, thereby saving energy and manpower.

[0088] The inventor of this patent has many years of experience in technological innovation, serving and even leading the megatrends of industrial automation, renewable energy and semiconductor equipment transformation. Our goal is to make due contributions to the food industry and society, so that people can get healthier, more delicious and reasonably priced food.

Claims

1. A device for cooling, pickling, and marinating food, which is capable of operating under extreme low-pressure conditions, comprising: a) A food freezer that can operate under extreme low-pressure conditions; b) A vacuum pump arranged to pump air out of the food freezer to achieve extreme low-pressure conditions; c) A cold trap arranged to condense water vapor from the food freezer back into a liquid form; d) A vacuum control valve arranged to isolate the cold trap and the food freezer and regulate the exhaust air flow; e) An inlet air control valve arranged to regulate the flow of added clean air and serve as a vent valve to allow the food freezer to return to atmospheric pressure; f) An electrical panel arranged to receive electricity and supply the electricity to the device; and g) A control and monitoring computer with an HMI screen, which implements freezer pressure control and enables a user to operate the device.

2. The device according to claim 1, wherein: The food freezer has a plurality of brackets for holding food trays or a trolley for holding a plurality of food trays.

3. The device according to claim 1, wherein: The extreme low-pressure conditions have a freezer pressure close to 0.1 ATM or 10 kPa.

4. The device according to claim 1, further comprising: a) An inline air filter for filtering the inlet air; b) A refrigeration unit for cooling the cold trap; c) A plurality of temperature sensors, the probes of which can be inserted into food samples in food trays to measure food temperature; d) A humidity sensor for measuring the humidity of the food freezer; and e) A pressure sensor for measuring the pressure of the food freezer.

5. The device according to claim 1, comprising a 2-input-1-output (2x1) pressure control system to control the food freezer pressure, which further comprises: a) A 1-input-2-output (1x2) pressure controller; b) A 2-input-1-output (2x1) pressure system; c) Actuator 1, which is the vacuum control valve; d) Actuator 2, which is the inlet air control valve; and e) A pressure setpoint trajectory calculation mechanism.

6. The control system according to claim 5, wherein: The 1-input-2-output (1x2) pressure controller is a model-free adaptive (MFA) controller, a proportional-integral-derivative (PID) controller, a proportional-integral (PI) controller, or a proportional controller (P), including a split-range setter to generate control outputs 1 and 2 to manipulate Actuator 1 and Actuator 2.

7. The 1x2 pressure controller according to claim 6, wherein: The split-range setter generates controller outputs in the following form: Or its equivalent form, where 0 < R1 ≤ 100, 0 ≤ R2 < 100, and the signals u(t), V1(t), and V2(t) all have a working range of 0 to 100.

8. The control system according to claim 5, wherein: The pressure set point trajectory calculation mechanism is capable of generating a set point for the controller to control the pressure of the food refrigerator to avoid liquid splash events of food flavor injection, wherein the set point trajectory is generated in the following form: or its equivalent, where Pi(0) >0 is the initial cabinet pressure, and a>0, b>0, d>0, C1>0, C2>0, C3>0 are predetermined constants used in the cooling recipe.

9. The control and monitoring computer with HMI screen according to claim 1, which is implemented in the following form: an industrial personal computer (IPC), or a programmable logic controller (PLC), or a programmable automation controller (PAC), or a specially designed control device, or a combination thereof.

10. A device for cooling, pickling or marinating food capable of operating under extremely low pressure conditions, the device comprising: a) A food refrigerator module, the food refrigerator module comprising: (i) a food refrigerator capable of operating under extreme low pressure conditions; (ii) a trolley capable of holding a plurality of food pans or trays; (iii) an inlet air control valve arranged to regulate the flow of added clean air and to act as a vent valve to allow the food refrigerator to return to atmospheric pressure; and (iv) dashboard; b) a utility module, the utility module being connected to the food refrigerator, the utility module comprising: (i) a vacuum pump arranged to pump air out of the food refrigerator to achieve an extremely low pressure condition; (ii) a cold trap arranged to condense water vapour from the food refrigerator back into liquid form; (iii) a refrigeration unit, the refrigeration unit being used to cool the cold trap; (iv) a vacuum control valve arranged to isolate the food cooler from the cold trap and to regulate exhaust air flow; (v) a vacuum air connecting pipe, the vacuum air connecting pipe connecting the food refrigerator and the cold trap so that air can pass through; (vi) an electrical panel arranged to receive electrical power and to supply electrical power to the device; and (vii) a conduit that receives electrical and signal wires between the food cooler module and the utility module; c) Control and monitoring module, including: (i) a computer and control equipment capable of controlling the freezer pressure of the apparatus; and (ii) An HMI screen that allows a user to operate the device.

11. The device according to claim 10, wherein: The extreme low pressure condition has a freezer pressure approaching 0.1 ATM or 10 kPa.

12. The device according to claim 10, wherein: The control and monitoring module also includes: a) a system power switch, the system power switch is used to turn the device on or off; and b) A plurality of system status lights, which are used to indicate the working or abnormal status of the device.

13. The device according to claim 10, wherein: The food refrigerator module also includes: a) an inline air filter, the inline air filter being used to filter the inflowing air; b) A plurality of temperature sensors, the probes of which can be inserted into food samples in a food tray to measure the food temperature; c) A humidity sensor for measuring the humidity of the food freezer; and d) A pressure sensor for measuring the pressure of the food freezer.

14. The device according to claim 10, comprising a 2-input-1-output (2x1) pressure control system to control the pressure of the food freezer, which further comprises: a) A 1-input-2-output (1x2) pressure controller; b) A 2-input-1-output (2x1) pressure system; c) Actuator 1, which is the vacuum control valve; d) Actuator 2, which is the incoming air control valve; and e) A pressure setpoint trajectory calculation mechanism.

15. The control system according to claim 14, wherein: The 1-input-2-output (1x2) pressure controller is a model-free adaptive (MFA) controller, a proportional-integral-derivative (PID) controller, a proportional-integral (PI) controller or a proportional controller (P), including a split-range setter to generate control outputs 1 and 2 to manipulate Actuator 1 and Actuator 2.

16. The 1x2 pressure controller according to claim 15, wherein: The split-range setter generates controller outputs in the following form: Or its equivalent form, where 0 < R1 ≤ 100, 0 ≤ R2 < 100, and the signals u(t), V1(t) and V2(t) all have a working range of 0 to 100.

17. The 1x2 pressure controller according to claim 15, wherein: The split-range setter is set with the values of R1 and R2 to achieve three working conditions, where: (a) The vacuum control valve is open and the incoming air flow valve is closed, and the freezer pressure decreases; (b) Both the vacuum control valve and the incoming air control valve are closed, and the freezer pressure remains stable; and (c) The vacuum control valve is closed and the incoming air flow valve is open, and the freezer pressure increases.

18. The control system according to claim 14, wherein: The pressure setpoint trajectory calculation mechanism is generated in the following form for cooling Type A food: Ps(t) = Pi(0) - a*t; during the initial ramp-down period; Ps(t) = C; during the first hold period; Or its equivalent form, where Pi(0) > 0 is the initial freezer pressure, and a > 0, C > 0 are predetermined constants used in the cooling recipe.

19. The control system according to claim 14, wherein: The pressure setpoint trajectory calculation mechanism is generated in the following form to control the pressure of the food freezer to avoid liquid splashing events during food flavor injection and cooling of Type B food: Or its equivalent form, where Pi(0) > 0 is the initial freezer pressure, and a > 0, b > 0, d > 0, C1 > 0, C2 > 0, C3 > 0 are predetermined constants used in the cooling recipe.

20. The computer and control device according to claim 10, which is implemented in the following form: an industrial personal computer (IPC), or a programmable logic controller (PLC), or a programmable automation controller (PAC), or a specially designed control device, or a combination thereof.

21. A food flavor injection method using an extreme vacuum cooling and flavor injection device with a food freezer, comprising: a) Meat and vegetables are soaked in a food dish covered with a marinade or brine; b) placing the food tray in the food refrigerator; c) inserting a temperature sensor probe into a food sample to measure the food temperature; d) Close the refrigerator door; e) Log in on the computer and HMI screen; f) selecting a food flavor infusion recipe from a recipe selection menu based on brine or marinade type and total weight; g) starting a food flavor infusion process, wherein the refrigerator pressure is controlled based on a predetermined pressure set point trajectory; h) wait for a predetermined waiting time; i) return the food refrigerator pressure to atmospheric pressure; as well as j) Removing the food pan from the food refrigerator.

22. The method according to claim 21, wherein: The food flavor infusion recipe includes a predetermined extreme low pressure condition wherein the freezer pressure is reduced to 0.01 ATM (1 kPa) or less.

23. The method according to claim 21, wherein: The food flavor infusion recipe is implemented via freezer pressure control based on a predetermined pressure set point trajectory that will prevent liquid splash events from occurring.

24. The method according to claim 21, wherein: The marinade or brine is soy sauce, teriyaki sauce, buttermilk, yogurt, ketchup, wine, liquor, vinegar, papaya juice, orange juice, kiwi juice, pineapple juice, apple juice, olive oil, salt water, or a combination of these ingredients.

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