SU1685360A1 - Method for defrosting of biological objects - Google Patents

Abstract

The invention relates to refrigeration technology and relates to a method of defrosting frozen biological objects. The purpose of the invention is to reduce energy consumption and intensify the process. To do this, biological objects are affected by an electron-ion flux generated by excitation of a corona discharge between electrodes. 1 hp f-ly, 2 ill., 1 tab.

Description

The invention relates to the field of refrigeration, in particular to methods of defrosting frozen biological objects, mainly meat, fish, endocrine raw materials, vegetables, etc.

There is a known method for defrosting products, which involves creating pressure in the chamber from 13 to 0.133 kPa and defrosting a product placed between the electrodes by bombarding it with ions and electrons when a glow discharge is excited.

The disadvantages of the known method are the need to evacuate to create a reduced pressure in the defrosting chamber. The implementation of the method requires the use of sealed chambers, which is extremely difficult to implement on an industrial scale. In addition, a high intensity of ion treatment in a glow discharge can lead to significant heating (more than 90 ° C) of biological objects and their death (for example, seeds) or a sharp decrease in quality (for example, meat).

The purpose of the invention is to reduce energy consumption and intensify the process.

According to the method of defrosting biological objects by exposing them to an electron-ion flux, the latter is generated by excitation of a corona discharge between electrodes.

Biological objects should be placed in the interelectrode gap or beyond

The method is carried out as follows.

Biological objects are affected by an electron-ion flux generated by excitation of a corona discharge between electrodes.

Corona discharge is a type of stationary electrical discharge in a gas arising in a highly inhomogeneous electric creep. The corona discharge is accompanied by the movement of gas particles from the corona electrode by an electric wind consisting of a stream of ions, electrons, charged particles and partly of neutral particles. The particle charge reaches a value close to the maximum in a very small fraction of a second (0.1-0.2 s). The corona standard ion concentration is 1012-1016 ions / m3

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When exposed to frozen biological objects by an air electron-ion flow, charged (diffusion process) and uncharged (convection) particles are deposited on the surface of objects and charged particles move from the surface inside biological objects. This process is accompanied by an increase in the temperature of biological objects due to heat exchange between the particles and the object and the release of heat during diffusion and convection processes, as well as the diffusion of particles into the objects.

The deposition rate of uncharged particles (molecular size) on biological objects is calculated by the formula

V - ° C Ve- -g-,

where D is the molecular diffusion coefficient of the particles;

C is the concentration of particles in the environment;

(e) is the thickness of the layer of particles near the surface of the biological objects being processed, where molecular diffusion takes place.

In the deposition of uncharged particles on the surface of an object, the difference in temperature of the medium and the surface of objects (thermal diffusion) is of great importance. When biological objects are deformed, the temperature difference reaches 20-60 ° С and more, which contributes to the intensification of the process.

Deposition rate of charged particles

Vr ne

b ur where e is the elementary electric charge;

E - tension sex;

tj is the viscosity of the medium;

p is the radius of the particles;

n is the number of elementary charges.

Thus, the effect on the frozen biological objects by the electron-ion flux generated by excitation of corona discharge between the electrodes leads to their defrostation.

When biological objects are placed in the interelectrode gap, the intensity of the defrostation process is observed as the concentration of ions and electrons is maximum in the interelectrode gap.

When biological objects are placed outside the interelectrode gap, energy consumption is reduced, since in this case the interelectrode distance can be minimized and power can be reduced.

spent on the excitation of a corona discharge, decreases with the reduction of the electrode distance.

A reduction in energy costs occurs and

due to the fact that evacuation of the defrosting chamber is not required,

The intensification of the process of defrosting biological objects occurs due to the electric wind that blows objects and consists of charged particles (ions and electrons) and uncharged particles,

FIG. 1 shows a scheme for carrying out the method of defrosting biological objects when placed in an interelectrode gap, top view; in fig. 2 - the same, when placing biological objects outside the interelectrode gap.

0 The implementation of the proposed method is carried out in a chamber (Fig. 1) with a conveyor 1, on which biological objects 2 are moved between the corona 3 and the grounded 4 electrodes, which are connected to the power supply 5. When voltage is applied to the electrodes 3 and 4, a corona discharge is excited between them, accompanied by the generation of an electron-ion flux, which, when it moves from the corona electrode 3 to the grounded electrode 4, acts on biological objects 2.

When placed on the conveyor 1 biological objects 2 outside the interelectrode

5 spacing (Fig. 2) along the conveyor 1, on two sides of it, are installed in pairs corona-forming 3 and grounded non-continuous 4 electrodes connected to the power source 5. Thus, on biological

0 objects are affected by an electron-ion flux generated by excitation between the corona discharge electrodes 3 and 4 and passing through a discontinuous grounded electrode 4.

5 Example 1. Defrostations are subjected to five blocks of meat (beef) weighing 7 kg each, having a temperature of -18 ° C. The process is carried out at an air temperature of 8 ° C and a relative humidity of p 95%.

0 Mass units (biological objects 2) are placed in the interelectrode space of the corona-forming electrode 3, which is a dielectric frame with wire wires

5 elements of nichrome wire with a diameter of 0.1-0.5 mm, and a grounded electrode 4, which is a stainless steel plate. A potential of 10–20 kV from a high voltage brush is fed to the discharge electrode.

Example 2. The process of defrosting is carried out analogously to example 1, with 15 bird carcasses of 2.0-2.5 kg each (chicken) having a temperature of 12 ° C being placed in the interelectrode gap.

Example 3. The process of defrosting is carried out analogously to example 1, with five blocks of fish (cod), 5 kg each, each having a temperature of -18 ° C being placed in the interelectrode gap.

Examples 4-6. The grounded electrode 4 is a steel grid of wire 1 mm in diameter with a cell size of 10x10 mm, the process is carried out under the conditions of example 1, while the biological objects, respectively, according to examples 1-3 are placed outside the interelectrode gap behind the grounded electrode.

The results of the studies in examples 1-6 are presented in the table.

The proposed method of defrosting biological objects has the following

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My advantages: the process of defrosting is intensified, as a result of which the processing time of biological objects is reduced by 20–40%; energy consumption for the implementation of the method is reduced by 30-50%; simplified work on the proposed method and equipment maintenance due to the absence of vacuum installations.

Claims (2)

1. A method of defrosting biological objects by exposing them to an electron-ion flux, characterized in that, in order to reduce energy consumption and intensify the process, the electron-ion flux is generated by excitation of a corona discharge between the electrodes. 2. A method according to claim 1, characterized in that the biological objects are placed in the interelectrode gap or beyond FIG.   3 VA G m, fig.Ј