Device for maintaining the temperature of a medical liquid contained in a container

Abstract

The utility model discloses a device for medical liquid heating constant temperature in container, including heating sheet, control module, temperature sensor and power module, heating sheet includes the flexible heating sheet body for the wrapping container, and heating sheet body is equipped with heating element, and heating element includes two or more than heating unit of independent temperature control by control module, and the area of each heating unit radiation constitutes a heating area, and each heating area is evenly arranged with temperature sensor of electric connection with control module, the arrangement mode of heating unit on heating sheet body satisfies: at least in one kind of use state, has two or more than heating area in the direction of gravity. The utility model not only can realize the quick heating of medical liquid in container, can also realize the constant temperature control after heating to target temperature.

Description

Technical Field

[0001] This utility model relates to the field of medical and nursing device technology, specifically to a device for heating and maintaining the temperature of medical liquids inside a container. Background Technology

[0002] Currently, sterile medical fluids are generally stored in sealed containers, such as saline bags, saline bottles, medicine bags, and medicine bottles. These containers are typically stored in operating rooms or hospital warehouses. The temperature in operating rooms is generally around 20°C, the ambient temperature, while the temperature in hospital warehouses may be even lower in winter. Human body temperature is typically 36°C to 37°C. Directly administering liquids at this temperature into the human body, such as into the gastrointestinal tract, can easily cause irritation, discomfort, or spasms in patients. Therefore, it is necessary to heat and maintain the temperature to human body temperature.

[0003] The existing methods for heating medical liquids mainly include the following:

[0004] The first method involves pouring the medical fluid into a sterile transfer storage container (the container is reusable and sterilized). A heating element at the bottom of the container directly heats the fluid through heat conduction. Patent application CN102631179A discloses a system for enhancing visual clarity in gastrointestinal endoscopy, which addresses the issues of low-temperature and highly irritating rinsing fluids by using a heating plate to heat the rinsing bottle (similar to a kettle principle) and a temperature sensor to monitor the temperature of the rinsing fluid inside. However, this method still requires a fixed container to store saline solution, meaning sterile saline solution still needs to be poured into this container before use. This presents problems such as complex operation, the need for repeated sterilization of the container, and potential contamination during operation and storage.

[0005] The second method involves hanging a medical liquid bag and securing it with two hollow heating pads (connected by an elastic band). The heater inside the hollow heating pad heats and maintains the temperature of the liquid inside the saline container. Patent CN211461513U discloses a portable, large-capacity saline heater, including a hollow first heating pad and a second heating pad connected by an elastic band. Both the first and second heating pads have heaters inside their cavities. However, this type of heater must be hung for use, and the heating pads can only conduct heat to the liquid inside the container through the sides against the outer wall. This results in low thermal conductivity, slow heating, and most of the heat dissipating upwards into the surrounding air, leading to poor heating efficiency. Furthermore, the overall structure and materials of the heater are very complex.

[0006] The third approach involves designing the liquid container as a specialized container incorporating heating pipes. Patent application CN204364573U discloses a heated infusion bag, comprising an infusion bag body and an infusion connector on the bag body. The bag body has a heating mechanism for heating the internal medication. This mechanism includes multiple heating tubes embedded in the side wall of the bag body, a thermally conductive insulating ring layer wrapped around the heating tubes, multiple arc-shaped protrusions evenly distributed on the outer circumference of the insulating ring layer, an auxiliary heating tube in each of the arc-shaped protrusions, and a power plug connected to the heating tubes and auxiliary heating tubes. While this patent achieves heating of the liquid to be delivered, it modifies the structure of the infusion bag itself, essentially making it a specialized container unsuitable for standard saline bags / bottles. Furthermore, the heating mechanism's placement on the side wall of the bag body also results in low heating efficiency. Additionally, infusion bags are typically disposable, significantly increasing usage costs and rendering them impractical. Summary of the Invention

[0007] To address the aforementioned issues, this invention provides a device for heating and maintaining the temperature of medical liquids within a container (hereinafter referred to as a "heating and temperature control device"). This device not only enables rapid heating of the medical liquids within the container but also achieves constant temperature control after heating to the target temperature.

[0008] The specific technical solution of this utility model is as follows:

[0009] This utility model discloses a device for heating and maintaining the temperature of medical liquids inside a container, which includes a heating element, a control module, a temperature sensor, and a power module for supplying power to the control module; the heating element includes a flexible heating element body for wrapping the container, and the heating element body is equipped with a heating element.

[0010] The heating element includes two or more heating units whose temperature is independently controlled by the control module. The area radiated by each heating unit constitutes a heating zone. Each heating zone is equipped with a temperature sensor electrically connected to the control module. The arrangement of the heating units on the heating element body satisfies the following condition: at least in one usage state, there are two or more heating zones in the direction of gravity.

[0011] The control module is configured to control the heating power of the heating zone where the temperature sensor is located based on the electrical signal output by the temperature sensor.

[0012] As an optional solution, the arrangement of the heating units on the heating element body satisfies the following condition: in the hanging state, there are two or more heating zones in the direction of gravity.

[0013] As an optional embodiment, the heating element body includes a thermally conductive layer with a thermal conductivity of 0.2 to 3 W / m·K for conducting the heat generated by the heating element; the thermally conductive layer is any one of silicone, rubber, or PVC containing thermally conductive fillers.

[0014] As an optional solution, the heating element body further includes an outer sheath layer stacked with the heat-conducting layer, and the heating element is disposed between the outer sheath layer and the heat-conducting layer; the outer sheath layer is any one of foamed silicone, nylon cloth, PVC cloth, and Oxford cloth.

[0015] As an optional solution, the heating element is a resistive heating element; the resistive heating element is one or more of the following: metal resistance wire, graphene film, flexible resistive heating film, carbon fiber heating element, and ceramic heating element.

[0016] As an optional solution, the temperature sensor is fixed inside the heating element body; the temperature sensor is any one of thermistor, resistance temperature detector, thermocouple, or integrated temperature sensor.

[0017] As an optional solution, a temperature control protection switch with an automatic reset function is also included; the temperature control protection switch is connected in series between the heating unit and the power module in the heating zone.

[0018] As an alternative, the heating element may further include fasteners and / or straps connected to the heating element body, the fasteners being used to secure the heating element body to the outer surface of the container it encloses, and the straps being used to hang the device.

[0019] As an optional solution, the control module includes a main control module and two or more sub-control modules connected in parallel to the main control module; the temperature sensor of each heating zone is electrically connected to the main control module and the sub-control module corresponding to the heating zone where the temperature sensor is located.

[0020] As an optional solution, the heating element body is also provided with an attitude detection sensor electrically connected to the control module; the attitude detection sensor includes at least one of a gravity sensor, an acceleration sensor, and an angle sensor.

[0021] As an optional solution, the control module includes a main control module and two or more sub-control modules connected in parallel to the main control module; the attitude detection sensor is electrically connected to the main control module, and the temperature sensor of each heating zone is electrically connected to the main control module and the sub-control module corresponding to the heating zone where the temperature sensor is located.

[0022] As an optional solution, the sub-control module includes a PID control unit and a PWM drive circuit; the PID control unit adjusts the heating power of the heating zone where the temperature sensor is located through the PWM drive circuit based on the electrical signal fed back by the temperature sensor.

[0023] This utility model has the following beneficial effects:

[0024] (1) Compared with the existing technology, the heating of medical liquid in infusion container can only be achieved through heat conduction. This utility model achieves a heating method that combines heat convection and heat conduction by designing the arrangement of heating zones in the device and combining independent temperature control of each heating zone. This greatly improves heating efficiency, reduces heating time, and reduces heat loss.

[0025] (2) In terms of temperature control, this utility model further combines closed-loop control algorithms such as PID, which can achieve precise temperature control during heating and constant temperature processes, and avoid container damage or personal injury caused by temperature exceeding the threshold or temperature overshoot.

[0026] (3) The present invention can be customized and flexibly set the number and arrangement of heating zones according to the type, size and shape of the infusion container, as well as the temperature control accuracy requirements and usage requirements.

[0027] (4) In the preferred embodiment of this utility model, a temperature sensor is configured in each heating zone of the heating element body. Based on the temperature of the heating zone detected by the temperature sensor, abnormal temperature changes in each heating zone are controlled to avoid the phenomenon of device loss due to empty heating of the heating zone caused by the decrease of medical liquid level (i.e., no medical liquid in the heating zone).

[0028] (5) In an optional embodiment of this utility model, an attitude sensor is configured on the heating element body. Based on the device usage status detected by the attitude sensor, the control module can allocate the initial heating power of the heating zone at different heights in the direction of gravity, promote the formation of heat convection, and further improve the heating efficiency.

[0029] (6) In the optional embodiment of this utility model, a temperature control protection switch is set between the heating unit and the power supply module in each heating zone. The temperature control protection switch and the control module are independent of each other, so as to provide dual protection for the device.

[0030] (7) In the optional scheme of this utility model, the thermal conductive layer is made of a flexible material with good adhesion and thermal conductivity of 0.2 to 3 W / m·K, especially thermally conductive silicone, which can ensure both adhesion and good thermal conductivity.

[0031] (8) This utility model heats medical liquids in a non-contact manner, eliminating the need to pour the medical liquids into a container first, simplifying surgical procedures, avoiding repeated sterilization of containers, and mitigating the risk of contamination from prolonged storage of liquids in containers. Furthermore, the device has a simple and reliable structure, is reusable, and has very low operating costs. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the heating and temperature control device described in Example 1. Figure 1 ;

[0033] Figure 2 This is a schematic diagram of the heating and temperature control device described in Example 1. Figure 2 ;

[0034] Figure 3 This is a schematic diagram of the circuit connection of the heating and temperature control device described in Example 1. Figure 1 ;

[0035] Figure 4 This is a schematic diagram of the circuit connection of the heating and temperature control device described in Example 1. Figure 2 ;

[0036] Figure 5 This is a schematic diagram of the heating and temperature control device described in Example 1 in use.

[0037] Figure 6 This is a schematic diagram of the heating and temperature control device described in Example 2;

[0038] Figure 7 This is a schematic diagram showing the usage state of the heating and temperature control device described in Example 2;

[0039] Figure 8 This is a schematic diagram of the heating and temperature control device described in Example 3;

[0040] Figure 9 This is a schematic diagram of the usage state of the heating and temperature control device described in Example 3. Figure 1 ;

[0041] Figure 10 This is a schematic diagram of the usage state of the heating and temperature control device described in Example 3. Figure 2 ;

[0042] Figure 11 This is a schematic diagram of the heating and temperature control device described in Example 3.

[0043] Attached image captions:

[0044] 100-Heating element, 110-Heating element body, 111-Outer sheath, 112-Heat-conducting layer, 113-Heating element, 114-Snap fastener, 120-Strap, 130-Hanging strap; 200-Control module (not shown in the figure); 300-Battery module (not shown in the figure); 400-Temperature sensor; 500-Temperature control protection switch. Detailed Implementation

[0045] The technical solution of this utility model will be clearly and completely described below with reference to specific embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0046] In the description of this utility model, the use of terms such as "upper," "lower," "left," "right," "front," "rear," "inner," "outer," "top," and "bottom," indicating orientation or positional relationships, is based on the orientation or positional relationships shown in the accompanying drawings. These terms are used solely for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the use of terms such as "first" and "second" is used to distinguish similar objects and is not necessarily used to describe a specific order or relative importance. Those skilled in the art can understand the specific meaning of the above terms in this utility model in conjunction with the specific circumstances. In addition, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, but rather to include other units not explicitly listed or inherent to these products or devices.

[0047] Combination Figures 1 to 5 As shown in Embodiment 1 of this utility model, a device for heating and maintaining the temperature of medical liquids inside a container (hereinafter referred to as the "heating and temperature control device") is disclosed, mainly including a heating element 100, a control module 200, a power supply module 300, and a temperature sensor 400. The temperature sensor 400 is integrated onto the heating element 100. The control module 200 and the power supply module 300 are typically independent of the heating element 100, but can be integrated as a single component and electrically connected to the heating element 100 via connectors or cables; alternatively, in other optional solutions, the control module 200 and the power supply module 300 can also be integrated with the heating element 100, but the influence of temperature changes on the heating element 100 should be minimized.

[0048] The heating element 100 mainly consists of a heating element body 110 and accessories such as straps 120 and hanging straps 130. Straps 120 are primarily used to secure the heating element body 110 after it wraps around the object being heated, ensuring close contact between the heating element body 110 and the object. Alternatively, straps 120 can be replaced with Velcro, elastic bands, etc., as long as they can secure the container within the heating element body 110. Hanging straps 130 are used for suspending the heating and temperature control device during use. The suspended state is generally considered the standard usage state, as is the hanging position. In addition, the device may also be used horizontally or at an angle, depending on the environment and requirements during use.

[0049] Understandably, in this invention, the object to be heated refers to the medical liquid contained in the container, and the container holding the medical liquid can be a commonly used infusion bag, infusion bottle, or other infusion container.

[0050] In terms of size design, the heating element body 110 can be designed as a rectangular structure with a length of 26mm and a width of 22mm. This size can basically cover commonly used 500mL infusion bags and 500mL infusion bottles. Of course, this size design can also be adjusted according to actual needs.

[0051] The heating element body 110 is a flexible structure used to wrap the infusion container. It mainly consists of an outer layer 111, a heat-conducting layer 112, and a heating element 113 disposed between the outer layer 111 and the heat-conducting layer 112. Figure 2 As shown. The outer layer 111 mainly serves waterproof, heat-insulating, and decorative purposes. For example, flexible materials such as foamed silicone, nylon cloth, PVC cloth, and Oxford cloth can be selected. The heat-conducting layer 112 is made of a flexible material with good thermal conductivity and good adhesion. The thermal conductivity is usually 0.2 to 3 W / m·K to ensure good thermal conductivity. For example, flexible heat-conducting materials such as silicone, rubber, and PVC with added alumina thermally conductive filler can be used. The surface of these flexible materials can be tightly attached to the outer surface of the container, thereby achieving efficient heat conduction and heating. The outer layer 111 and the heat-conducting layer 112 can be connected and fixed at the edges, which can be achieved by sewing, snaps 114, and Velcro, or it can be integrally formed with the heating element 113 by pressing.

[0052] The heating element 113 is mainly used to generate heat, and a resistive heating element is preferred. It should be noted that the heating element 113 located between the outer sheath 111 and the thermally conductive layer 112 is laid out in zones according to requirements, that is, it has multiple independently temperature-controlled heating units, and the area radiated by each heating unit constitutes a heating zone. The heating element body 110 usually has more than two heating zones.

[0053] In one alternative embodiment, the heating element 113 is a metal resistance wire, preferably made of a high-temperature resistant, low-cost, and long-term-operational iron-chromium-aluminum alloy. The resistance wire can be arranged in a serpentine pattern and fixed to the surface of the heat-conducting layer 112 by means of bonding or other methods. Understandably, since the resistance wire is flexible and bendable, and is embedded in the flexible heating element body 110, it can be coiled to wrap around and conform to the outer surface of the container being heated.

[0054] In another alternative, the heating element 113 is made of graphene film. Graphene has the advantages of high thermal conductivity, high electrothermal conversion efficiency, uniform heat distribution, good flexibility, and long life, but its price is relatively high. Therefore, graphene film can be selected as the heating element 113 in applications requiring high flexibility.

[0055] In another alternative, the heating element 113 is a flexible resistive heating film, such as a PI heating film or a PET heating film. The flexible resistive heating film mainly consists of a flexible substrate and conductive materials attached to or embedded in the substrate; it generates heat when energized, thus being a resistive heating element.

[0056] In another alternative, the heating element 113 is a carbon fiber heating element. Carbon fiber itself is conductive, and heat is generated due to the resistance effect (Joule heating) when electricity is applied. Carbon fiber heating elements have advantages such as far-infrared radiation, lightweight, and corrosion resistance, but their high-temperature resistance is slightly inferior. Therefore, carbon fiber heating elements can be selected as the heating element 113 in scenarios requiring low-temperature heating or for containers with large external areas.

[0057] In another alternative, the heating element 113 is a ceramic heating element. The ceramic heating element is a conductive ceramic doped with antimony tin oxide and silicon carbide, and it also belongs to the resistive heating element category. Ceramic heating elements are characterized by high temperature resistance and corrosion resistance, but they lack flexibility. Therefore, in non-flexible application scenarios, a ceramic heating element can be selected as the heating element 113.

[0058] It's worth noting that heat conduction and heat convection are two different modes of heat transfer. Heat conduction transfers heat through the thermal motion of microscopic particles such as molecules, atoms, or free electrons, occurring in solids, liquids, and gases. Heat is transferred from a high-temperature region to a low-temperature region. Conduction is more efficient in solids but slower in liquids and gases. Heat convection, on the other hand, transfers heat through the macroscopic motion of fluids, primarily occurring in liquids and gases. The motion of the fluid significantly improves heat transfer efficiency, making it considerably more efficient than heat conduction.

[0059] Specifically, in this invention, when a temperature difference exists within a liquid, energy transfer occurs through the microscopic vibrations, displacements, and collisions of molecules, atoms, and electrons within the liquid. This allows heat to be conducted from the high-temperature region to the low-temperature region, which is the most common heat conduction method used in liquid heating. During the heating of medical liquids within a container, when a temperature gradient exists in the direction of gravity and the high-temperature region is located at the bottom, the density difference drives natural objects, generating thermal convection. For example, when the fluid at the bottom is heated, the resulting hot fluid expands and decreases in density, creating buoyancy that causes the hot fluid to rise, while the cold fluid above sinks due to gravity, thus forming a convective circulation that transfers heat. In infusion containers, the heating rate of medical liquids via thermal convection is significantly higher than that via thermal conduction.

[0060] In Example 1, the heating pad body 110 has two heating zones along its wrapping direction (i.e., the horizontal direction in the hanging state). The heating pad body 110 can be folded along its centerline to wrap the infusion container (such as an infusion bag or bottle) containing medical fluid, and the medical fluid in the infusion container is heated through these two heating zones. It is understood that the corresponding area is called a heating zone because this area corresponds directly to the location of a set of heating elements 113, and is the area radiated by the heating elements 113. Each heating zone is equipped with a set of heating elements 113, and the temperature of the heating elements 113 in each heating zone is independently controlled by the control module 200.

[0061] The control module 200 is mainly used to heat and control the temperature of the heating element 113 in the heating element body 110, so as to achieve rapid heating and constant temperature of the heated object, namely the medical liquid. Figure 3 As shown, the control module 200 typically includes a main control module and multiple sub-control modules. The number of sub-control modules is usually in one-to-one correspondence with the number of heating units, and multiple sub-control modules are connected in parallel to the main control module.

[0062] The main control module simultaneously receives electrical signals from the temperature sensors in all heating zones, while each sub-control module only receives electrical signals from the temperature sensors in its own heating zone. Based on the received electrical signals, the main control module can intelligently allocate the maximum heating power of each sub-control module and control each sub-control module to reduce its heating power or stop heating altogether.

[0063] like Figure 4 As shown, the sub-control module mainly consists of a PID control unit and a PWM drive circuit. The PID control unit can be an MCU that implements the PID algorithm through embedded software (such as STM32F407) or a dedicated PID controller (such as MAX31856).

[0064] During operation, the temperature sensor feeds back the real-time temperature signal to the PID control unit of the sub-control module. The PID control unit calculates the error between the feedback value (i.e., the real-time temperature signal data detected by the temperature sensor) and the set value (e.g., 37 degrees Celsius) using a PID algorithm. Based on this error, it outputs a corresponding control signal and generates a PWM signal with a corresponding duty cycle through the signal generator in the PWM drive circuit. This controls the on and off times (i.e., duty cycle) of the switching transistors in the PWM drive circuit to precisely regulate the heating power of the heating element 113, thus forming a closed-loop control. For cost considerations, the PID control unit is preferably implemented in software. For example, multiple PWM drive circuits can share a single MCU to form multiple PID closed-loop control circuits, which can independently control the heating power of each heating zone.

[0065] The power module 300 can use AC mains input, which is converted to low-voltage AC by a transformer and then rectified and regulated to output DC power. This is suitable for scenarios with high lifespan requirements or low cost requirements. Alternatively, it can use AC mains input, which is converted to low-voltage DC output by a switching power supply. This has high power conversion efficiency and is suitable for general scenarios or scenarios with compact size requirements. It can also use battery input, which is converted to low-voltage regulated DC output by a DC-DC circuit. This is suitable for scenarios without AC mains input or in outdoor environments.

[0066] Each heating zone is equipped with a temperature sensor 400 to detect the real-time temperature of the object being heated within its zone and transmit the temperature signal to the control module 200. The temperature sensor 400 can be a thermistor (NTC / PTC), resistance temperature detector (RTD), thermocouple, or an integrated temperature sensor (e.g., DS18B20, which directly outputs a digital signal). The temperature sensor 400 is integrated into the heating element body 110, specifically either embedded in the thermally conductive layer 112 or fixed to the inner side of the thermally conductive layer 112 (closer to the object being heated) by adhesive bonding, sewing, or other methods.

[0067] It is important to note that since the temperature sensor 400 is positioned between or embedded in the heat-conducting layer 112 and the infusion container, the temperature it detects is, more accurately, the temperature at the interface between the heat-conducting layer 112 and the infusion container. If the heat-conducting layer 112 is in indirect contact with the medical fluid inside the infusion container through the container—that is, if the heat-conducting layer 112 is in close contact with the container wall and there is medical fluid in the heating area—the detected temperature indirectly reflects the temperature change of the object being heated in the heating area. Therefore, the detected temperature can be considered the temperature of the object being heated in the heating area. However, if the infusion container is separated from the heat-conducting layer 112 or there is no medical fluid in the heating area, the temperature detected by the temperature sensor 400 only reflects the temperature change in its own heating area.

[0068] Understandably, infusion bags and infusion bottles are two common types of infusion containers. Infusion bags are typically flexible, i.e., soft bags, with a fully enclosed design. They drain fluid using negative pressure, and as the fluid volume decreases, the infusion bag deforms. When the infusion bag deforms to a certain extent, it may separate from the heating zone. In this case, the temperature change rate (i.e., the slope of the temperature change curve) detected by the control module 200 (specifically, the main control module) will show an anomaly (e.g., a sudden increase in the slope). Therefore, it can be set that when the temperature change rate difference exceeds a set threshold, the control module 200 will reduce the heating power of the heating zone (e.g., heating at a set minimum power Pmin) or stop heating altogether.

[0069] Infusion bottles are typically made of glass or plastic, and are rigid structures. Air needs to be introduced into the bottle through a vent to drain the fluid, preventing deformation of the bottle body. Similarly, as the fluid level decreases in an infusion bottle, the heating element 113 in the upper heating zone only contacts the bottle wall and cannot directly transfer heat to the liquid through the bottle wall. The heating element 113 only heats the bottle body it contacts. Consequently, the temperature detected by the temperature sensor 400 cannot reflect the temperature change of the object being heated; it only represents the temperature change at the interface between the heat-conducting layer 112 and the infusion bottle. At this time, the temperature change rate detected by the temperature sensor 400 in the upper heating zone is significantly different from that detected by the temperature sensor 400 in the lower heating zone. The main control module will control the power supply module 200 to allocate all or most of its electrical energy to heat the lower heating zone, while the upper heating zone is not heated or only a small portion of its electrical energy is used for heating. This means controlling the heating power of the upper heating zone to decrease (e.g., heating at a set minimum power Pmin) or stopping heating altogether, thereby ensuring constant temperature or rapid heating while reducing heat loss.

[0070] In one alternative approach, when the heating and temperature control device starts heating, the main control module distributes the initial heating power equally to each heating zone of the infusion container. During heating, based on PID closed-loop control, the heating power is adjusted according to the real-time temperature detected by the temperature sensor 400, and the heating power of each heating zone may no longer be equal. Simultaneously, the main control module also monitors the rate of temperature change (i.e., the slope of the temperature change curve) continuously detected by the temperature sensor 400 in real time. When the rate of temperature change of one or more heating zones exceeds a set threshold, it indicates that there is no medical fluid in the heating zone, and it may only be heating the infusion container. The control module will then reduce the heating power of that heating zone, either by heating at the set minimum heating power Pmin or by stopping heating altogether.

[0071] It's worth noting that, on the one hand, PID closed-loop control can achieve constant temperature control after heating to the target temperature; on the other hand, since the temperature detected by the temperature sensor 400 is not the actual temperature of the object being heated, but rather an indirect measurement through the container, overheating may occur when monitoring the target temperature during heating. For example, if there is no medical fluid in the heating zone, it could lead to overheating damage to the infusion bag; or after initially heating to the target temperature, the actual temperature of the heated fluid may lag behind, resulting in overheating beyond a certain range of the target temperature. This could lead to the administration of fluid exceeding the target temperature into the patient, causing discomfort or even tissue thermal damage, harming the body. Therefore, PID control can effectively reduce or avoid over-threshold or temperature overshoot problems.

[0072] However, it is understood that the closed-loop control algorithm of this invention is not limited to the PID algorithm. The PID algorithm is suitable for scenarios requiring precise temperature control and low temperature error requirements, such as when the temperature is directly input to sensitive parts of the human body. In other solutions, especially in scenarios where the temperature is within a certain range and the temperature error requirement is not high, such as when liquids come into contact with human skin, the bang-bang control algorithm can also be used to achieve closed-loop temperature control.

[0073] In Example 1, the heating pad body 110 has two heating zones in the horizontal direction. In use, the infusion container containing medical fluid is wrapped inside the heating pad body 110 and secured with straps 120. It is understood that infusion bags are generally flat, and infusion bottles are generally round. During use, the two heating zones of the heating pad body 110 are respectively attached to the two sides of a flat infusion bag or the outer periphery of a round infusion bottle, and the heating element 113 heats the medical fluid inside the infusion bag or bottle. In normal use, i.e., in the hanging state, the infusion bag or bottle is placed vertically, and the contact area between the two horizontal heating zones and the medical fluid is basically symmetrical, with little difference in heating power; heating is primarily by heat conduction.

[0074] The applicant understands that, in addition to the normal hanging position, infusion containers are also used in horizontal or angled positions. For example, in some operating rooms or emergency rooms, there may be situations where hooks are unavailable or occupied, making it impossible to hang the infusion containers (infusion bags / bottles), forcing them to be placed horizontally or at an angle. Similarly, in some outdoor or ordinary environments, hooks are often unavailable, again necessitating the horizontal or angled placement of the infusion containers. Therefore, it is necessary to heat the medical fluids inside the horizontally or angled containers to a constant temperature of body temperature (around 37°C). Furthermore, some surgeries or examinations are very short, such as gastroscopy or colonoscopy, which typically last about an hour, or when the interval between surgeries is short, significantly increasing the required heating rate of sterile medical fluids. The fluids need to be rapidly heated to body temperature (around 37°C) and maintained at a constant temperature within a very short time, which is difficult to achieve using only heat conduction.

[0075] In the aforementioned special usage scenarios or when a heating rate is required, the infusion container should be kept flat or tilted during use. For example... Figure 5 As shown, the heating and temperature control device described in Example 1 is in a horizontal position. On the one hand, since the liquid in the infusion container cannot completely fill the container, especially the infusion bottle, the upper heating zone a1 has difficulty directly heating the medical liquid through heat conduction from the container wall. This results in the liquid temperature above the container being significantly lower than the liquid below, creating a temperature gradient in the vertical direction (i.e., the direction of liquid gravity). Furthermore, as the amount of liquid in the container gradually decreases, the upper surface of the infusion bag may no longer be in contact with the upper heating zone a1, and the distance between the upper surface of the liquid in the infusion bottle and the upper heating zone a1 gradually increases, making the heat conduction heating method of the upper heating zone a1 increasingly ineffective. The applicant unexpectedly discovered that although the heat conduction effect of the upper heating zone a1 deteriorates at this time, it promotes the formation of heat convection heating. Therefore, by reducing the heating power of the upper heating zone a1 or directly stopping the heating of the upper heating zone a1, it is possible to further promote the rapid heating and temperature maintenance of the medical liquid in the infusion container through a combination of heat convection and heat conduction when the infusion container is used horizontally or at an angle.

[0076] It is worth noting that in Example 1, two heating zones are set in the wrapping direction, and this arrangement is more suitable for the flat bag-shaped structure of infusion bags. For the circular cross-section structure of infusion bottles, multiple heating zones can be set at equal intervals in the horizontal direction, and each heating zone can be independently temperature controlled. These heating zones are evenly distributed circumferentially around the axis of the infusion bottle after the heating plate body 110 wraps the infusion bottle, forming a surrounding heating.

[0077] Optionally, each heating element 113 is also equipped with a temperature control protection switch 500. The temperature control protection switch 500 is connected in series between the power supply module 300 and the heating element 113 to provide over-temperature protection. When the temperature of the heating element 113 exceeds a set threshold, the circuit is automatically cut off, stopping the heating element 113 from operating. This prevents the heating element 113 from exceeding the set safe temperature due to failure or abnormality of components such as the temperature sensor 400 and the control module 200. The temperature control protection switch 500 can be set at any position between the power supply module 300 and the heating element 113, for example, on the surface or inside of the heat-conducting layer 112 or the outer sheath 111 of the heating element 100, or it can be set on the external power supply cable. The temperature protection switch 500 is independent of the main control module, providing a backup double protection function. For example, it can be set to automatically cut off at 45 degrees Celsius (above the constant temperature of 37 degrees Celsius) and close again after returning to 45 degrees Celsius, with the main control module controlling the constant temperature. The temperature control protection switch 500 can be selected from various types, including bimetallic temperature control switches with automatic reset function, snap-action temperature controllers, and electronic temperature control switches.

[0078] Based on the heating and temperature control device provided in Example 1, the applicant conducted a set of comparative experiments. The comparative example is a patent scheme similar to that in publication number CN211461513U, which does not employ zoned heating. Both Example 1 and the comparative example were placed in a flat position, and the experimental data are shown in Tables 1 and 2, respectively.

[0079] Table 1:

[0080]

[0081] Table 2:

[0082]

[0083] As can be seen, by adopting the scheme described in Example 1, the heating efficiency is significantly improved, and under the same conditions and starting point, the time to reach 37 degrees is reduced by half.

[0084] Combination Figure 6 and Figure 7 As shown, Embodiment 2 discloses another heating and temperature control device, which differs from Embodiment 1 mainly in the arrangement of the heating zones on the heating element body 110. In Embodiment 2, the two heating zones are arranged vertically, meaning that in the normal hanging state, the medical fluid is temperature-controlled by different control modules in the direction of gravity. The horizontal arrangement of the same heating zone on the heating element body 110 ensures that the two surfaces of the infusion bag or the infusion bottle are heated evenly around the circumference, and the length of the heating zone completely covers the infusion bag or infusion bottle as much as possible to increase the heating area.

[0085] like Figure 7As shown, initially, the heating power of the upper and lower heating zones is set to be equal. However, as the liquid in the infusion container decreases and the liquid level drops, the temperature detected by the temperature sensor 400 in the upper heating zone 2a will change from reflecting the temperature of the medical liquid to only reflecting the temperature at the interface between the heat-conducting layer 112 and the infusion container. At this time, the temperature change rate may exceed the set value, thereby triggering the reduction of the upper heating zone 2a to the set minimum heating power P. min Initiate heating or stop heating altogether.

[0086] As a preferred option, when the container is suspended, the upper heating zone 2a can be set to heat with a lower heating power P1 and the lower heating zone 2b with a higher heating power P2 at the start of heating. This creates a significant temperature gradient in the direction of gravity for the medical fluid from the outset, enabling rapid heating or temperature maintenance of the medical fluid in the infusion container during normal use (suspended state) through a combination of heat convection and heat conduction. As the infusion container is used, the liquid level gradually decreases. If an abnormal temperature change rate is detected in the upper heating zone 2a (e.g., exceeding a set threshold), the heating power of the upper heating zone 2a can be further reduced to the minimum heating power P. min Or stop heating. It's worth noting that this method not only facilitates heat convection but also reduces heat loss, significantly improving heating efficiency. Furthermore, this method is also applicable to the heating and temperature control device shown in Example 1. Wherein, P min ≤P1 <P2。

[0087] Understandably, the heating zone arrangement in Example 2 is particularly suitable for routine use. To further refine temperature control and improve heating efficiency, multiple equally spaced heating zones can be arranged along the direction of gravity of the medical liquid, i.e., the vertical direction, with each zone having independent temperature control. Furthermore, compared to Example 1, Example 2 creates a temperature difference in the hanging state, i.e., a temperature difference along the long side or axial direction of the container. The temperature gradient is more pronounced, resulting in more significant heat convection and higher heating efficiency.

[0088] Combination Figures 8 to 10 As shown, Embodiment 3, based on Embodiments 1 and 2, discloses a heating and temperature control device. Two or more heating zones are provided in both the horizontal and vertical directions of the heating element body 110, and each heating zone is independently temperature-controlled. The advantage of Embodiment 3 compared to Embodiments 1 and 2 is that, in the conventional use state (vertical hanging), heating zones 3a and 3b are located above heating zones 3c and 3d, as shown... Figure 9As shown, heating zones 3c and 3d can be set to heat with higher heating power, while heating zones 3a and 3b can be heated with lower heating power or not heated at all. This overcomes the deficiency of Embodiment 1, which cannot heat the liquid inside the container faster through thermal convection when the container is hung vertically. When used in a flat or inclined position, heating zones 3a and 3c are located above heating zones 3b and 3d (and vice versa). Figure 10 As shown, heating zones 3a and 3c can be configured to heat with higher heating power, while heating zones 3b and 3d can be heated with lower heating power or not heated at all. This overcomes the deficiency in Embodiment 2, where the liquid inside the container cannot be heated more quickly through thermal convection when the container is placed horizontally or at an angle. In other words, this heating zone design in Embodiment 3 can heat the liquid inside the container more quickly through thermal convection regardless of the placement method.

[0089] It is worth noting that in other alternative solutions, two or more heating zones can be set in both the horizontal and vertical directions, and the number of heating zones in the two directions does not have to be equal. For example, two heating zones can be set in the horizontal direction, and four heating zones can be set at equal intervals in the vertical direction. The four heating zones can be independently temperature controlled to achieve precise temperature control of medical liquids, while also further improving heating efficiency and reducing heat loss.

[0090] Furthermore, to achieve intelligent control, this invention can add a gravity sensor or orientation sensor, or other attitude sensor, to the heating device to detect its usage status, such as whether it is hanging or lying flat. Based on the detected usage status, the control module allocates the initial heating power to each heating zone.

[0091] Taking a gravity sensor as an example, in Embodiment 3, the gravity sensor can be placed at any position on the heating element 100. Specifically, various types of sensors can be selected, such as mechanical cantilever sensors made of elastic sensitive elements, piezoelectric sensors, etc. When the heating and temperature control device starts heating, the main control module can automatically determine the current placement of the infusion container based on the gravity sensor and select the optimal solution for control.

[0092] Specifically, the gravity sensor transmits an electrical signal representing its current orientation to the main control module, allowing the main control module to differentiate and control the heating power of each heating zone. For example, if the gravity sensor detects that the device is hanging vertically, it transmits a logic digital signal of "0" to the digital signal input of the main control module. The main control module then controls the PWM drive circuit through the corresponding sub-control module, heating zones 3c and 3d with a higher heating power P2 from the start of heating, while heating zones 3a and 3b are heated with a lower heating power P1.

[0093] Preferably, the present utility model can also use an angle sensor to replace a gravity sensor or a direction sensor, which can accurately determine different inclination angles in a hanging state, a flat placement state and an inclined placement state, so as to achieve reasonable power distribution during initial heating. The angle sensor can be arranged at any position of the heating sheet 100, and a static inclination angle sensor and other types of sensors can be selected.

[0094] In an initial state, the main control module automatically determines the current placement mode and inclination angle of the infusion container based on the angle sensor, and allocates each heating area according to the optimal heating power ratio. For example, in a vertical hanging state, the angle sensor senses Figure 8 the direction shown by the middle arrow, that is, the included angle X with the horizontal plane is 90 degrees, which is the Figure 9 the state shown, the analog voltage signal information is directly transmitted to the A / D input terminal of the main control module, or after being converted by an analog-to-digital circuit, the digital signal is directly transmitted to the digital signal input terminal of the main control module. When the main control module receives the angle signal of 90 degrees, it controls the lower heating zones 3c and 3d to heat at a higher heating power P2 and the upper heating zones 3a and 3b to heat at a lower heating power P1 through the sub-control modules.

[0095] Further, calculation can also be performed according to the angle value of X, so that different angles correspond to different heating powers, and more accurate initial power distribution can be achieved.

[0096] Taking Figure 11 as an example, during initial heating, the settings can be as follows:

[0097] P 3a0 =k1*P max

[0098] P 3b0 =k2*P max

[0099] P 3c0 =k3*P max

[0100] P 3d0 =k4*P max

[0101] When X=0°, k3=k4>k1=k2;

[0102] When 0°<X<90°, k3>k4>k1>k2;

[0103] When X=90°, k4=k3>k2=k1;

[0104] When 90°<X<180°, k4>k3>k2>k1;

[0105] When X=180°, k2=k4>k1=k3;

[0106] When 180°<X<270°, k2>k1>k4>k3;

[0107] When X=270°, k1=k2>k3=k4;

[0108] When 270°<X<360°, k1>k2>k3>k4;

[0109] In the formula, P max is the set maximum heating power of a single heating area, the angle range of X is 0° to 360°, 0≤k1,k2,k3,k4≤1, P min ≤P1<P2≤P max .

[0110] Wherein, the value rule of k1, k2, k3, k4 needs to be matched according to the characteristics of the heated object to achieve the best effect.

[0111] Figure 11 In the present utility model, the sub-control module controls the duty cycle of the PWM driving circuit based on the calculation result, and further controls the initial heating power P of the heating zone 3c 3c0 , so as to achieve heating with the optimal heating power at the initial stage.

[0112] It can be understood that in other embodiments, the container carrying medical liquid in the present utility model is not necessarily an infusion container, it can also be a liquid carrying container for cooling and heating (temperature control) of medical devices, such as water cooling and liquid cooling constant temperature systems for medical devices; a liquid carrying container in medical devices for human treatment or physiotherapy, such as hyperthermia and hot compress medical devices; a liquid carrying container for heat dissipation and heat conduction of medical device components, such as a container for liquid circulating in an energy generation area (such as a microwave ablation needle head, a laser output end of laser ablation) in microwave ablation and laser ablation medical devices; a liquid carrying container for filling use, such as a liquid container for filling a medical balloon; a liquid carrying container for medical devices that play a conductive role in treatment, such as a normal saline container for radiofrequency ablation; a liquid carrying container for cleaning and defogging medical device components, such as a liquid carrying container for cleaning and defogging endoscope lenses; or a medical liquid carrying container combining multiple functions described above. The present utility model does not limit this.

[0113] Finally, embodiment 4 of the present utility model discloses a heating control method applied to the above heating thermostat, which mainly includes the following parts:

[0114] Initial heating power control: This section mainly applies to the distribution of heating power when the heating and temperature control device starts heating. The main control module calculates the initial heating power of each heating zone based on the electrical signal output by the attitude detection sensor. For specific control methods, please refer to the description in Example 3, which will not be repeated here.

[0115] Closed-loop control: This section applies to temperature control during the normal heating process of the heating and temperature control device. The sub-control module dynamically adjusts the heating power of the heating zone where the temperature sensor is located based on the electrical signal fed back from the temperature sensor, using a closed-loop control algorithm to achieve closed-loop control of the target temperature. Specific control methods can be found in the description of Example 1, and will not be repeated here.

[0116] Abnormal temperature change control: This section is mainly applicable to situations where abnormal conditions occur during the heating process of the heating and temperature control device. For example, when the medical liquid level drops and the heating zone becomes empty (i.e., there is no medical liquid in the heating zone), or when the heat-conducting layer of the heating and temperature control device separates from the container wall, resulting in the failure or abnormality of the temperature sensor or control module.

[0117] When the main control module detects that the temperature change rate of the heating zone where the temperature sensor is located exceeds a set threshold based on the electrical signal output by the temperature sensor, it controls the heating power of the heating zone to reduce to the set minimum power or stops heating. For specific control methods, please refer to the descriptions in the above embodiments, which will not be repeated here.

[0118] In summary, this invention, through the arrangement of the heating zones and independent temperature control, achieves heating and temperature control of medical liquids in containers by combining heat conduction and heat convection. This avoids the need for repeated sterilization of the containers and the potential for contamination, as well as the problem of excessive temperature difference between the liquid temperature introduced into the human body and the temperature of the gastrointestinal tract. At the same time, it greatly improves heating efficiency and reduces heat loss.

[0119] Finally, it should be noted that although the technical solution of this utility model has been described above in conjunction with the accompanying drawings and embodiments, this utility model is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and guiding, and not restrictive. Those skilled in the art, under the guidance of this specification, can make many other forms without departing from the scope of protection of the claims of this utility model, and these all fall within the scope of protection of this utility model.

Claims

1. A device for maintaining a constant temperature of a medical liquid in a container, characterized in that, It includes a heating element, a control module, a temperature sensor, and a power supply module for supplying power to the control module; The heating element includes a flexible heating element body for wrapping the container, and the heating element body is equipped with a heating element; the heating element includes two or more heating units that are independently temperature-controlled by the control module, the area radiated by each heating unit constitutes a heating zone, and each heating zone is equipped with a temperature sensor electrically connected to the control module. The arrangement of the heating units on the heating element body satisfies the following condition: at least in one usage state, there are two or more heating zones in the direction of gravity.

2. The apparatus of claim 1, wherein, The arrangement of the heating units on the heating element body satisfies the following condition: when hung, there are two or more heating zones in the direction of gravity.

3. The apparatus of claim 1, wherein, The heating element body includes a thermally conductive layer with a thermal conductivity of 0.2 to 3 W / m·K for conducting the heat generated by the heating element; the thermally conductive layer is any one of silicone, rubber, or PVC containing thermally conductive filler.

4. The apparatus of claim 3, wherein, The heating element body also includes an outer sheath layer stacked with the heat-conducting layer, and the heating element is arranged between the outer sheath layer and the heat-conducting layer; the outer sheath layer is any one of foamed silicone, nylon cloth, PVC cloth, and Oxford cloth.

5. The apparatus of claim 1, wherein, The heating element is a resistive heating element; the resistive heating element is one or more of the following: metal resistance wire, graphene film, flexible resistive heating film, carbon fiber heating element, and ceramic heating element.

6. The apparatus of claim 1, wherein, The temperature sensor is fixed inside the heating element; the temperature sensor is any one of thermistor, resistance temperature detector, thermocouple, or integrated temperature sensor.

7. The apparatus of claim 1, wherein, It also includes a temperature control protection switch with an automatic reset function; The temperature control protection switch is connected in series between the heating unit and the power module in the heating zone.

8. The apparatus of claim 1, wherein, The heating element also includes fasteners and / or straps connected to the heating element body. The fasteners are used to fix the heating element body to the outer surface of the container it covers, and the straps are used to hang the device.

9. The device of any one of claims 1 to 8, wherein, The control module includes a main control module and two or more sub-control modules connected in parallel to the main control module; the temperature sensors of each heating zone are electrically connected to the main control module and the sub-control module corresponding to the heating zone where the temperature sensor is located.

10. The apparatus of claim 9, wherein, The heating element body is also equipped with an attitude detection sensor that is electrically connected to the main control module; the attitude detection sensor includes at least one of a gravity sensor, an acceleration sensor, and an angle sensor.

11. The apparatus of claim 9, wherein, The sub-control module includes a PID control unit and a PWM drive circuit; the PID control unit adjusts the heating power of the heating zone where the temperature sensor is located through the PWM drive circuit based on the electrical signal fed back by the temperature sensor.

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