RU2552822C1 - Method of defrosting of liquid medical and food products and device for its implementation - Google Patents

Abstract

FIELD: electricity.SUBSTANCE: method of defrosting and/or heating of liquid medical and food products, including components of blood, blood plasma and so forth, situated in flexible or solid vessels, provides contact action of the thermal source on products due to use as a heat source of the elastic electric heating module which densely wrap the vessel with a product. Meanwhile during heating the product in the vessel is being mixed from the moment of thawing. The efficiency of the heating module is increased due to displacement of air bubbles from the space between the vessel and the heat source by dense wrapping of the vessel with the elastic electric heating module. Meanwhile the process of product defrosting is monitored and controlled. At decrease of rate of change/growth of temperature Vi > Vi+1 is the mixer is switched on. The device for implementation of the method of defrosting and/or heating of frozen liquid medical or food products consists, at least, of one vessel with a product, the heat source, the mixer and the control unit. The heat source is the elastic electric heating module consisting of an elastic electric heating element placed in an electric insulating shell. The mixer is a platform fitted with the drive and the control unit on which the vessel with the electric heating module is fixed.EFFECT: device and the method allow to provide sufficiently uniform heating at direct contact with frozen liquid medical and food products without using the intermediary heat carrier, ensure intergity of defrozen products at significant decrease of power consumption per unit of defrozen product, possibility of creation of small-sized, independent defroster capable to work both from network power supplies, and from board and independent power supplies with low operating voltage that improves the safety of operation of such devices and creates conditions for significant expansion of scope of application.10 cl, 4 dwg

Description

The invention relates to the field of electrical engineering and can be implemented for practical purposes in medical, biological, domestic devices and devices, for example, for thawing liquid medical and food products.

By defrosting we mean the whole process of heating liquid frozen medical and food products (hereinafter referred to as products) from the start of heating when the products are frozen, then transferring the product from solid to liquid and bringing the liquid product to the required temperature.

Technical devices for defrosting and heating blood components have been around for a long time. There are known analogues of the methods and designs of devices developed both in Russia and abroad. Let's consider some of them.

There is a method of defrosting blood products, including blood plasma, including immersing plastic bags with components of blood frozen to a temperature of -25 ÷ -30 ° C and below in a special bath with water at a given temperature until completely thawed, and the packets with drugs are first thawed blood to a temperature of 0 ÷ + 4 ° C, the achievement of the specified temperature is judged by lowering the water level in the bath to the calculated value determined by the formula

Δh = n (V _mn -V _zn ) / S,

Δh is the set value for reducing the water level in the bath during plasma thawing, determined empirically, n is the number of packets of frozen plasma placed in the bath at a time, V _mn is the volume of the packet with frozen (solid) blood plasma, V _zn is the volume of the packet with thawed (liquid) blood plasma, S is the bath area, and then the timer for the estimated time to bring the temperature of the packets with blood components to 7 ÷ 8 ° C (to obtain the VIII factor) or 35 ÷ 37 ° C (for administration to a patient with hemophilia or Willibrand disease) (Patent RU 2280460, IPC C2, 2004).

A known method for thawing medical and food products, especially for deep-frozen canned plasma or blood, which is provided with at least two plastic bags containing a heating agent and located on both sides of the product to be heated. In addition, this method uses a device in the form of a compressing body, which acts constantly on at least one plastic bag so that the heating agent and, therefore, the medical product are forced to perform a swinging movement (Patent EP 0318924, IPC A1, 1989) .

Also known is a method for thawing and / or heating medical products, special low-frozen blood solutions or injections, or infusions for subsequent transfusion, conversion or injection. The inventive method covers heating modules on which a container containing a low-frozen product is placed. A preheated elastic pad is placed on the container and provides a heating process for the container. The heating temperature is monitored using a temperature sensor, and heating stops when the desired temperature is reached (Publication WO 0204052, IPC A1, 2002).

A device for defrosting a blood plasma is known, including a special bath with a working fluid, for example, distilled water, a heating and cooling device, a temperature sensor and a control circuit, as well as an electric stirrer connected to the executive circuit of the control circuit, characterized in that it is equipped with a level sensor liquid in the bath connected to the input of the control circuit, and the bath is equipped with channels for the flow of liquid from the end of the bath to the beginning (in the compartment, for the location of the plasma packets in the chessboard ohm order), the evaporator of the cooling device and the heating element are located directly in the bath, and the liquid level sensor is located in the bath compartment, separated from the rest of the bath by vertical partitions and communicating with the bath through the connecting hole in the lower part of the specified compartment, and is additionally introduced into the control circuit timer (Patent RU 2280460, IPC C2, 2004).

The methods and apparatus considered that ensure the thawing of components, liquid medical and other products, including blood plasma, allow the functional safety of the elements included in these products to be maintained during heating.

These methods and device create the conditions for heating products using a coolant (in many cases, distilled water). Since the coolant has a rather large volume and mass, considerable energy (~ 1 kW or more) is spent to heat it and maintain the required temperatures. With such capacities, the use of on-board and, moreover, autonomous sources of electricity that ensure the operation of defrosters is not possible, therefore all defrosters of this type work only from stationary electric networks with a voltage of 220 V.

In addition, voids are formed between the coolant and the container with the defrosted product, filled with air, which are additional thermal insulators, which leads to an additional (inefficient) energy consumption. To eliminate them, additional devices are used that greatly complicate the design of the defroster.

The objective of the invention is to develop a method and design defrosting, not having the above disadvantages or, at least, to reduce these disadvantages.

To avoid excessive energy consumption and unproductive expenditure of the resource of the electric drive of the stirrer, it is advisable to include it when the defrosted product begins to melt. Up to this point, the frozen product is ice and there is no need to mix it.

Simplification of the defrosting design, which should not affect the safety of the elements that make up the blood, for which the existing analogues used a rather complex defrosting design and the corresponding defrosting control system to maintain the entire temperature in a certain temperature range, since it should be fairly uniform .

In addition, it should be borne in mind that the currently used similar defrosters have, due to the large dimensions of complex control systems and material consumption, a high cost.

The technical result achieved in this case is the creation, on the basis of the proposed method, of a new device that ensures the safety of defrosted products with a significant reduction in power consumption per unit of defrosted product, the possibility of creating small-sized, autonomous defrosters that can operate both from mains power sources and from onboard and autonomous sources power supply with low operating voltages, which increases the safety of operation of such devices and flushes the conditions for a significant expansion of the scope of application.

The proposed method of thawing liquid medical and food products, including blood components, blood plasma, etc., located in flexible or solid containers, includes contact heating of the container with the product by a heat source, mixing the product during heating and controlling the heating process of the product through the unit control, while before heating the product, air bubbles are displaced from the space between the heat source and the tank, for which elastic Woven fabric electric heating module, which tightly wrap the container with the product. The product is heated in a predetermined temperature regime, while the current temperature is measured at regular intervals on the surface of the tank, and the data is transmitted to the control unit to ensure a given temperature regime of the temperature change, determined by the formulas:

;

;

V _i - the rate of change of temperature from T ₁ to T ₂ over a period of time Δt = Δt _i = t ₂ -t _{1 is} compared with the rate of change of temperature for the next equal time period V _{i + 1} , and when the product is heated, stirring is made from the moment of melting of the product that is, when the condition V _i > V _{i + 1} is satisfied.

A device is proposed that implements the above method of thawing and / or heating frozen liquid medical or food products, which consists of at least one container for placing products, a heat source, a stirrer, and a control unit. As a heat source, an elastic electric heating module is used, which tightly wraps the container with the product, and to ensure uniform heating of the product, the device is equipped with a stirrer and a unit for monitoring and controlling the process of defrosting the product. When V _i > V _{i + 1} , the stirrer is switched on. Using the proposed device allows for fairly uniform heating of the container with frozen liquid medical and food products without the use of a heat transfer agent, which allows to achieve a significant (~ 5 times) reduction in the level of energy consumption for defrosting and heating of products, as well as to achieve a significant simplification of the design and reduction of dimensions defrost, expand the scope.

The invention is illustrated by drawings, which represent the following:

figure 1 shows a graphical dependence of the temperature on the outer surface of the container with the product from time to time during defrosting;

figure 2 presents the design of the defrost;

figure 3 and figure 4 shows the design of the elastic electric heating module in the unfolded and wrapped form, respectively.

The proposed method of thawing liquid medical and food products, including blood components, blood plasma, etc., includes contact heating of products in flexible or solid containers by exposure to a heat source that covers the container with the product, while in the process heating the container with the product, the product is mixed and the temperature regime is controlled as it is heated using the control unit. Before heating the container with the product, it becomes necessary to displace air bubbles from the space between the container and the heat source. In this method, this problem is solved by using an elastic electric heating module as a heat source, consisting of at least one elastic electric heating element located in an insulating sheath, while between the electric heating element and the insulating sheath on the side not facing the tank, heat-insulating material, while the mixer is a movable platform equipped with a drive and a control unit, on which is fixed on the tank with an electric heating module, and the control unit is connected with temperature sensors mounted on the surface of the elastic electric heating module from the side facing the tank, the electric heating element and the stirrer drive. Using an elastic electric heating module, the container with the product is tightly wrapped. Also, in the process of heating the tank, the temperature of the heating and the rate of change of temperature on the surface of the tank with the product are controlled and the product is mixed from the moment it melts, as well as the control of the heating level. The stirrer is turned on at the beginning of the drop in the rate of temperature change at V _i > V _{i + 1} . The flexible electric heating element and the mixer are turned off when the set temperature is reached, for example, the mixer is turned on at V _{i + 1} <13 ° C / min, control of the heating temperature level to T ₃ ≤38 ° C (Figure 1). The temperature parameters that are controlled during the heating process are determined by the formula and include:

;

;

V _i - the rate of change of temperature on the surface of the tank for a fixed period of time Δt = Δt _i ;

V _{i + 1} - the rate of change of temperature on the surface of the tank for the next equal period of time Δt = Δt _{i + 1} ;

V _i > V _{i + 1} - comparison of the rate of change of temperature, when this condition occurs, the stirrer is turned on;

T ₃ ° C - the required temperature of the product, upon reaching which the defrost is switched off.

A device that implements the above method for defrosting medical and food products (FIG. 2) consists of an elastic electric heating module (1) with which a flexible or rigid container (2) with a product is tightly wrapped. The container is located and fixed on the mixer platform (3), which has the ability to swing on the axis of rotation (4) located on the supports (5) of the base of the defrosting case (6). The platform (3) is driven by an electric drive (7) through rods (8) and hinges (9). The elastic electric heating module (1) (Figure 4) is an electrical insulating shell (10), in which an elastic electric heating element (11) is placed, and between it and the electrical insulating shell (10) from the side opposite to the location of the container (2), a heat-insulating material (12), and from the side of the tank (2) there is only an elastic electric heating element (11) and an insulating shell (10). In order to remove air bubbles, the container (2) is tightly wrapped by an elastic electric heating module (1). Alternatively, the elastic electric heating module (1) in expanded form (Figure 3) can be made rectangular with side valves (13) with fasteners (14) in the form of Velcro. A sensor (15) is installed on the inner surface of the elastic electric heating module (1), which provides temperature control connected by electric wires to the control unit (16), through which the operating modes of the elastic electric heating element (11) and the electric drive (7) of the mixer (17) are controlled. The control unit (16), an elastic electric heating element (11), an electric drive (7) of the stirrer are connected to a stationary or mobile power supply via electric wires (18) and a connector (19) (not shown in Fig.). In order to ensure higher hygiene, the space between the platform and the base of the body is covered with a cover (not shown in Fig.). As an elastic electric heating element (11), one of the design options for a heating element can be used: woven, knitted, wire or based on a synthetic film.

The operation of the device is as follows: a flexible or rigid container (2) is taken, in which there is a frozen liquid medical or food product, is tightly wrapped by an elastic electric heating module (1), on the inner surface of which there is a temperature sensor (15). An elastic electric heating module (1) when mounted on a moving platform (3) of a stirrer (17) on the tank is fixed with fasteners (14). The defroster is connected to a source of electricity through wires (18) and a connector (19). Switching on is performed using the control unit (16). After switching on, heating of the elastic electric heating element (11) begins. When the rate of temperature change on the surface of the container with the product (2) drops, and this happens when the product melts, the control unit (16) generates a signal and turns on the electric drive (7) of the mixer. An elastic electric heating element (11) and an electric drive (7) of the stirrer operate until a predetermined temperature is reached on the surface of the container (2) with a defrosted / heated product. When the set temperature is reached, the control unit (16) generates a signal and turns off the elastic electric heating element (11) and the electric drive (7) of the mixer. With a temperature indicator, manual defrost control is possible.

Claims (10)

1. A method of defrosting and / or heating medical and food products in flexible or solid containers, comprising contact heating the container with the product with a heat source, mixing the product during heating and controlling the heating process of the product through a control unit, characterized in that before by heating the product, air bubbles are displaced from the space between the heat source and the tank, for which an elastic fabric electric heating mode is used as a heat source ul, which tightly wraps the container with the product, and the product is heated in a predetermined temperature mode, while the current temperature is measured at regular intervals on the surface of the container, and the data is transmitted to the control unit to ensure the specified temperature regime of the temperature change determined by the formulas:
$$V_i=\frac{\Delta T_i}{\Delta t_i}=\frac{T_2-T_{\mathrm{one}}}{(t_{\mathrm{one}}+\Delta t)-t_{\mathrm{one}}}=\frac{T_2-T_{\mathrm{one}}}{t_2-t_{\mathrm{one}}}$$

;
V _i - the rate of change of temperature from T ₁ to T ₂ over a period of time Δt = Δt _i = t ₂ -t _{1 is} compared with the rate of change of temperature for the next equal period of time V _{i + 1} , and when the product is heated, stirring is made from the moment of melting of the product that is, when the condition V _i > V _{i + 1} is satisfied. 2. Device for thawing and / or heating medical or food liquid products, containing a container for placing products, a heat source for contact heating, a mixer and a control unit, characterized in that the container with the product is tightly wrapped on all sides by a heat source, which is made in in the form of an elastic electric heating module, consisting of at least one elastic electric heating element located in the insulating shell, while between the electric heating element m and an insulating shell on the side not facing the container, there is a thermal insulation material, while the mixer is a movable platform equipped with a drive and a control unit, on which a container with an electric heating module is fixed, and the control unit is connected to temperature sensors installed on the surface of an elastic electric heating the module from the side facing the tank, the electric heating element and the stirrer drive. 3. The device according to claim 2, characterized in that a woven or knitted electric heater is used as an elastic electric heating element. 4. The device according to claim 2, characterized in that an electric heater based on a synthetic film is used as an elastic electric heating element. 5. The device according to claim 2, characterized in that a wire-based electric heater is used as an elastic electric heating element. 6. The device according to claim 2, characterized in that an electric motor with a gearbox is used as the drive of the moving platform. 7. The device according to claim 2, characterized in that a retractor relay is used as the drive device of the moving platform. 8. The device according to claim 2, characterized in that two or more elastic electric heating modules are used as a heat source. 9. The device according to claim 2, characterized in that in order to ensure higher hygiene, the space between the platform and the base of the body is covered with a hydro and electrical insulating cover. 10. The device according to claim 2, characterized in that the drive drives the platform using traction and hinges.

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