RU2803542C1 - Microwave convective continuous flow hop dryer with tiered resonators of different configurations - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: invention can be used in hop farms for drying freshly harvested hops. Microwave convective hop dryer contains tiered hemispherical 4, cylindrical 10 and truncated conical 15 non-ferromagnetic resonators. They are joined together by bases 6, 12 of equal diameter. Along the perimeter of resonators 4, 10, 15, waveguides with air-cooled magnetrons 26, 24, 22 are installed with a shift of 120 degrees, the emitters of which are directed into the corresponding resonators. In each non-ferromagnetic resonator 4, 10, 15, dielectric perforated cellular electric drums 5, 9, 16 are installed coaxially vertically with a height equal to the height of the corresponding resonator and a diameter equal to the diameter of the small base 17 of the truncated conical resonator 15. On the hemispherical resonator 4, where the segment 2 is cut out corresponding to the size of the cross section of the drum cell 5, a non-ferromagnetic loading tank 1 is installed. On all bases 6, 12, 17 of the resonators at the level of the cells of the dielectric drums 5, 9, 16, radial segments are cut corresponding to the radius of the drum. The segment chord size is not more than two wave penetration depths. The electric drive 3 of the cellular drum 5 of the first tier is located on the surface of the hemispherical resonator 4. The second cellular drum 9 is set in motion due to the engagement of the toothed dielectric gear and the dielectric ring 11 on the drum 9. The electric drive 19 of the third cellular drum is located outside the truncated conical resonator 15. Under the open segment 18, on a small base 17 of a truncated conical resonator 15, there is a non-ferromagnetic receiving capacitance 20. Air outlets 27, 7, 13 and air ducts 25, 23, 21 from heat guns are attached to the side surfaces of all resonators 4, 10, 15 from opposite sides, directed from bottom to top, against the movement of raw materials in the cells of the drums in height.

EFFECT: use of the invention improves the quality of hop processing.

1 cl, 8 dwg

Description

The invention relates to the field of agriculture and can be used in hop farms for step-by-step drying of freshly harvested hops in a continuous mode while maintaining consumer properties.

The Russian hop dryer XC-400, which uses a convective drying method, was tested in the Chuvash Republic. The total energy consumption of the XC-400 hop dryer is 20 GJ for drying 1 ton of hops, with a humidity of 75-82%. The drying air temperature is not more than 65 ^o C, the final humidity of dried hops is 6%, the humidity of conditioned hops is 11% [1]. It is known that due to the duration of the process and uneven drying of hop cones, its consumer characteristics are reduced. Convective air supply at a temperature of 65 ^o C does not reduce the development of microflora or the appearance of mold. Therefore, up to 15% of first-grade hops can lose value and will be assessed as second grade.

The task of drying hops comes down to preserving a good presentation, color and aroma, the maximum amount of bitter substances (12-22%), tannins (2-5%) and essential oils (0.2-0.8%) for its use in brewing

The scientific problem is the low energy efficiency of hop dryers with convective heat supply and the lack of small-sized continuous flow hop dryers for hop farms that ensure the preservation of the consumer properties of hops at reduced operating costs.

The closest in technical essence is a microwave - convective hop dryer with tiered resonators in the form of hemispheres and an ellipsoid (patent No. 27749612). The hop dryer contains coaxially and tiered resonators in a vertically located cylindrical shielding housing [2].
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Disadvantage: the difficulty of matching the thickness of the hop layer with the penetration depth of the electromagnetic wave in the centimeter range, which entails uneven dielectric heating of the hops. High metal consumption due to the presence of a shielding housing.

The technical result of the invention is the preservation of the consumer properties of dried and disinfected hops during three-stage drying in different modes in a working chamber formed by tiered non-standard resonators.

To solve a technical problem and achieve the stated technical result, a continuous-flow microwave convective hop dryer with tiered resonators of different configurations contains

tiered hemispherical, cylindrical and truncated conical non-ferromagnetic resonators, joined together by bases of equal diameter, along the perimeter of which waveguides with air-cooled magnetrons are installed with a 120-degree shift, the emitters of which are directed into the corresponding resonators,

Moreover, with a diameter equal to the diameter of the small base of the truncated cone, dielectric perforated cellular electric drive drums with a height equal to the height of the corresponding resonators are installed coaxially vertically in each non-ferromagnetic resonator,

in this case, a non-ferromagnetic loading capacity is installed on the hemispherical resonator, where a segment is cut out the size of the cross-section of the drum cell,

and on all the bases of the resonators, at the level of the cells of the dielectric drums, radial segments are cut out corresponding to the radius of the drum, and with a chord of no more than two wave penetration depths,

wherein the electric drive of the cellular drum of the first tier is located on the surface of the hemispherical resonator, and the second cellular drum is driven by the engagement of the toothed dielectric gear and the dielectric rim on the drum, the electric drive of the cellular drum of the third tier is located outside the truncated conical resonator,

in this case, under the open segment on the small base of the truncated conical resonator there is a non-ferromagnetic receiving tank, and air vents and air ducts from the heat gun are attached to the side surfaces of all resonators on opposite sides, directed from the bottom up, against the movement of raw materials in the drum cells.

The essence of the invention is illustrated by drawings, which show:

- microwave convective hop dryer of continuous flow action with tiered resonators of different configurations, general view in section with positions (Fig. 1);

- microwave convective hop dryer of continuous flow action with tiered resonators of different configurations, general view, sectional view (Fig. 2);

- hemispherical non-ferromagnetic resonator (Fig. 3);

- cylindrical non-ferromagnetic resonator (Fig. 4);

- non-ferromagnetic truncated conical resonator (Fig. 5);

- dielectric perforated cellular drum of the first tier (Fig. 6);

- dielectric perforated cellular drum of the second tier (Fig. 7);

- dielectric perforated cellular drum of the third tier (Fig. 8);

A continuous-flow microwave convective hop dryer with tiered resonators of different configurations contains (Fig. 1−8):

- non-ferromagnetic loading container 1;

- open segment 2 on a hemispherical non-ferromagnetic resonator;

- electric drive 3 of the cellular dielectric perforated drum 5 of the first tier;

- hemispherical non-ferromagnetic resonator 4;

- cellular perforated dielectric drum 5 in a hemispherical non-ferromagnetic resonator 4;

- non-ferromagnetic base 6 of the hemispherical resonator 4;

- non-ferromagnetic air vent 7 on a cylindrical resonator 10;

- open segment 8 on the base 6 of the semi-cylindrical resonator 4;

- cellular perforated dielectric drum 9 in the second cylindrical non-ferromagnetic resonator 10;

- a dielectric crown 11 with a gear for driving a dielectric perforated cellular drum 9 of the second tier;

- lower base 12 of a cylindrical non-ferromagnetic resonator 10;

- non-ferromagnetic air vent 13 on a truncated conical resonator 15;

- open segment 14 on the lower base 12 of the cylindrical non-ferromagnetic resonator 10;

- non-ferromagnetic truncated conical resonator 15;

- cellular perforated dielectric drum 16 in a truncated conical resonator 15;

- small base 17 of the truncated conical resonator 15;

- open segment 18 on the base 17 of the truncated conical resonator 15;

- electric drive 19 of the cellular dielectric drum 16 of the third tier;

- non-ferromagnetic receiving capacity 20;

- air ducts 21, 23, 25 with heat guns into the corresponding resonators 15, 10, 4;

- waveguides with magnetrons 22, 24, 26 on corresponding resonators 15, 10, 4;

- air vent 27 on a hemispherical resonator 4.

A continuous-flow microwave convective hop dryer with tiered resonators of different configurations contains tiered hemispherical 4, cylindrical 10 and truncated conical 15 non-ferromagnetic resonators. They are connected to each other by bases 6 and 12 of equal diameter. Along the perimeter of the resonators 4, 10, 15, waveguides with air-cooled magnetrons 26, 24, 22 are installed with a shift of 120 degrees, the emitters of which are directed into the corresponding resonators.

Moreover, with a diameter equal to the diameter of the small base 17 of the truncated conical resonator 15, in each non-ferromagnetic resonator 4, 10, 15 dielectric perforated cellular electric drive drums 5, 9, 16 with a height equal to the height of the corresponding resonators are installed coaxially and vertically. On the hemispherical resonator 4, where segment 2 is cut out the size of the cross-section of the cell of the drum 5, a non-ferromagnetic loading capacity 1 is installed. On all bases 6, 12, 17 of the resonators, at the level of the cells of dielectric perforated drums 5, 9, 16, radial segments are cut out corresponding to the radius of the drum . The chord of the radial segment is no more than two wave penetration depths (6-7 cm). The electric drive 3 of the cellular perforated dielectric drum 5 of the first tier is located on the surface of the hemispherical resonator 4. The second cellular perforated drum 9 is driven by the engagement of the toothed dielectric gear and the dielectric rim 11 on the drum 9. The electric drive 19 of the third cellular drum is located outside the truncated conical resonator 15 Under the open segment 18 on the small base 17 of the truncated conical resonator 15 there is a non-ferromagnetic receiving capacitance 20. Air vents 27, 7, 13 and air ducts 25, 23, 21 from the heat gun are attached to the side surfaces of all resonators 4, 10, 15 on opposite sides, directed from bottom to top, against the movement of raw materials in the cells of drums 5, 9, 16.

The technological process of drying freshly harvested hops is as follows. Pour hop cones into loading container 1, after closing the valve in it. Turn on electric drives 3, 11, 19 of all cellular perforated dielectric drums 5, 9, 16. Turn on heat guns to supply warm air (65 ^o C) through the corresponding air ducts 25, 23, 21. Open the damper in the loading tank 1 and turn on sequentially, according to as hops enter through open segments 2, 8, 14 into the cells of the corresponding perforated dielectric drums 5, 9, 16, microwave generators (magnetons 26, 24, 22). In cellular perforated drums, freshly harvested hops are exposed to EMF (frequency 2450 MHz, wavelength 12.24 cm, penetration depth 3-3.5 cm) and convective heating. In the hemispherical resonator 4, during the rotation of the perforated cellular dielectric drum, surface moisture is removed, heated by convection, evaporated and carried away through the air vent 27. Hop cones are endogenously heated to 31-34 ^o C due to polarization currents. The cross-section of the drum cells is presented as a radial segment, while the chord of this segment is no more than two wave penetration depths (6-7 cm), so the raw materials are heated evenly in the drum cells. When the perforated dielectric drum 5 rotates, hop cones from the cells through the open segment 8 enter the cells of the perforated drum 9 of the second tier. In the cylindrical resonator 9 of the second tier, under the influence of EMPSHF of the appropriate dose and convective heating, the hop cones are heated to 35-55 ^o C. In this case, the bound moisture, due to the pressure gradient, tends to the periphery of the surface of the hop cones, is heated by convective heat, evaporates and is carried away by convective air through the air vent 7. The partially dried raw material, through the open radial segment 14 on the base 12, enters the cells of the perforated drum 16 located in a truncated conical resonator. In this resonator, under the influence of microwave emfs of the appropriate dose and convective heat, hop cones are heated to 56-70 ^o C. In a truncated conical resonator, the electric field strength is high (1.2-2 kV/cm), sufficient to disinfect hops. The bound moisture is endogenously heated, evaporates and carried away with convective air through the air outlet 13. The hops, dried to 9-10% humidity with a total microbial number of less than 500 thousand CFU, are poured through the open segment 18 into the receiving container 20.

The drying rate of hop cones depends on the transfer of mass and heat inside the capillary-porous cone and on the external mass and heat exchange of the hop surface with the environment in the drums. The drying regime should not be constant throughout the entire hop drying process, but should change during the process in accordance with the patterns of heat and moisture transfer in hop cones. Therefore, to implement a variable mode of drying hops, the working chamber is divided using three resonators of different configurations. By supplying coolant of certain parameters to individual resonators of the hop dryer, using the microwave convective method of heat supply, control of drying modes is achieved. Since the quality of dried hop cones is the main indicator, the choice of coolant temperature is determined by the electrical properties of the hop.

The quality of dried hops depends on the temperature and air pressure, the dose of exposure to the ultrahigh frequency electromagnetic field, and the electric field strength at each stage of drying, so at least a three-stage drying process should be followed. The drying speed of hops depends on the specific power of the generators in each resonator and on the parameters of the coolant: temperature, speed and relative humidity. The proposed microwave technology and microwave convective hop dryer provide the greatest uniformity of drying of hop cones, with complete release of moisture to the coolant if the air pressure is sufficient, but below the speed of soaring of the cones.

Kinetics of hop drying: in a dielectric perforated drum of the first tier, the hops heat up and the drying speed increases. Then, in the second tier drum, a period of constant drying speed begins, characterized by a constant hop temperature and a constant rate of moisture evaporation. Depending on the electrical and thermophysical properties of hops and the operating parameters of the microwave convective process, the temperature varies within a wide range (35-55 ^o C). The temperature of the hops during the period of constant drying rate should be significantly below 100 ^o C, so that the evaporation of moisture mainly occurs not inside the hop cones, but on its surface [3, p. 328].

In the drum of the third tier, after the end of the period of constant speed (in the second tier), the intensity of evaporation decreases, and the temperature of the hops increases (56-70 ^o C). With this three-zone drying process technology, the intensity of hop drying is high, allowing it to preserve its consumer properties at low energy costs. The EMHF energy is spent only on creating the necessary temperature and pressure gradient inside the hop cones, and the evaporation of moisture occurs due to convective heating.

So, combined drying is convenient for selective evaporation of moisture from the complex structure of hop cones, containing different forms of moisture bonding. Warm air is supplied to each resonator at a certain pressure and flow rate, which passes through a layer of hop cones and is removed through air vents. The moisture contained in the cones turns into a vapor state and is removed by air flow through the perforations of the drums and air vents. The highest air temperature in the resonators is allowed no more than 65 ^o C, and the speed of movement of the heated air should not exceed 0.5 m/s. The hops are dried to a moisture content of 9-10%.

The hop dryer provides step-by-step removal of moisture from hop cones while moving through resonators using cellular perforated drums. In this case, hop cones are subjected to endogenous convective heating, dried and disinfected, i.e. consumer characteristics are preserved and microbiological indicators are improved.

In all resonators, the dose of exposure to EMF microwaves, the temperature and pressure of the supplied air are controlled and regulated depending on the humidity and volume of loaded hops by changing the power of microwave generators and heat guns, as well as the speed of the conveyor.

Information sources

1. Order No. 738-r on approval of the Concept for the development of hop growing in the Chuvash Republic for 2020-2025. [Electronic resource]. Access regime: km.cap.ru›doc/laws/2020/08/20/disposal-738-r.

2. Patent No. 27749612 RF, IPC S12S3/02; F26B3. Ultra-high-frequency hop dryer with tiered resonators (tubing)/Prosviryakova M.V., Storchevoy V.F., Goryacheva N.G., Mikhailova O.V., Novikova G.V.; applicant and patent holder RGAU-MSHA named after K.A. Timiryazeva (RU). – No. 2021129382; application 08.10.2021. Bull. No. 18 dated June 24, 2022.

3. Lykov A.V. Drying theory. M. Energy, 1968, 470 p.

Claims (1)

A continuous-flow microwave convective hop dryer, characterized by the fact that it has tiered non-ferromagnetic resonators of hemispherical, cylindrical and truncated conical shapes, connected to each other by bases of equal diameter, while waveguides with air-cooled magnetrons are installed along the perimeter of the resonators with a shift of 120 degrees , the emitters of which are directed into the corresponding resonators, in addition, in each non-ferromagnetic resonator, dielectric perforated cellular electric drive drums are installed coaxially vertically, having a diameter equal to the diameter of the small base of the truncated conical resonator, and a height equal to the height of the corresponding resonators, and in the hemispherical resonator a segment of size cross-section of the drum cell, in which a non-ferromagnetic loading capacity is installed, and on all bases of the resonators, at the level of the cells of dielectric drums, radial segments are cut out corresponding to the radius of the drum, and with a chord of no more than two wave penetration depths, while the electric drive of the cellular drum of the first tier is located on surface of the hemispherical resonator, the second cellular drum is driven by the coupling of the toothed dielectric gear and the dielectric rim on the drum, and the electric drive of the third tier cellular drum is located outside the truncated conical resonator, in addition, under the open segment on the small base of the truncated conical resonator there is a non-ferromagnetic receiving container, and air vents and air ducts from the heat gun are attached to the side surfaces of all resonators on opposite sides, directed from the bottom up against the movement of raw materials in the drum cells.