RU2798374C1 - Tiered hop dryer with dielectric and convective heating sources - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: tiered hop dryer with sources of dielectric and convective heating, characterized in that it contains tiered non-ferromagnetic resonators, made in form of truncated cones with exponential generatrix and concave bases, to which concave ceramic mirrors are coaxially attached, and the diameters of the concave bases of non-ferromagnetic resonators are equal to each other and are multiples of half the wavelength, and the lengths of the resonators are different, gradually decreasing towards the lower tier, and are similarly multiples of half the wavelength, dielectric screws with individual electric drives are coaxially located inside the resonators, while along the perimeter of the concave bases of the resonators with a shift of 120 degrees, waveguides with air cooling magnetrons are placed, in addition each resonator has non-ferromagnetic air ducts from individual heat guns are connected at the side of the concave bases, and air vents which are below-cutoff waveguides covered with non-ferromagnetic fine mesh grids are attached at the side of the truncated parts of the resonators, while sluice gates with electric drives are installed above the upper and lower resonators.

EFFECT: invention allows preserving consumer properties of hops while improving its microbiological parameters.

1 cl, 6 dwg

Description

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

Freshly harvested hop cones contain 76-82% moisture. It is known that at a temperature of 110°C, 68% of alpha acids, 59% of beta acids are oxidized within an hour, and 80-90% of essential oils evaporate. Therefore, hop drying technology is subject to stringent requirements.

Of the existing devices for drying hops, hop dryers based on the convective drying method, for example, the PCB-750 hop dryer, Czech production, and the XC-400 hop dryer, are most widely used. But biochemical analysis shows that the convective drying method does not fully ensure the preservation of the consumer properties of hop cones due to uneven heating over the cross section of the cones. The temperature gradient directed from the surface to the center of the cones counteracts the moisture gradient directed from the center of the cone to the periphery. Because of this, dried hop cones have an uneven color of a golden-greenish hue, and crumpled and crushed hop cones exceed 15% of the mass. In addition, the efficiency of drying hops by the convective method depends on the moisture absorption capacity of the atmospheric air. Even under favorable conditions, the drying quality remains low due to the uneven drying of hops, associated with the heterogeneity of the cones, the uneven thickness of the hop layer and the uneven distribution of heated air in the chamber. Energy costs per unit of production remain high, and due to the violation of drying technology, up to 40% of first-class hops are transferred to the second grade [1].

Therefore, the development of equipment and the implementation of an intensive technology for drying hops with sources of dielectric and convective heating, which makes it possible to increase the uniformity of drying due to the selective action of an electromagnetic field of ultrahigh frequency (2450 MHz, wavelength 12.24 cm).

In such a dryer, resonators are the working elements. Of particular interest are resonators with low energy losses during the oscillation period relative to the energy stored in the system. Important is the value that characterizes the product of the intrinsic quality factor of the resonator and the resonant frequency of the oscillation. It is known that for microwave electromagnetic cavity resonators this value reaches up to 2-10 Hz at a frequency of 2450 MHz. Promising cavity resonators are resonators with focusing mirrors made of ceramics and sapphire [2]

Known microwave convective hop dryer with elliptical toroidal resonators [3, patent No. 2772987]. It contains resonators with curved surfaces arranged in series in a horizontal plane, docked through ceramic biconvex perforated plates. Convective heat is supplied from the heat gun through air ducts to each resonator. The concentration of the energy of the electromagnetic field in the volume of the resonator and the reduction of radiation losses is achieved through the use of a biconvex ceramic plate. The disadvantage is the complexity of the design of the resonators.

Known microwave convective hop dryer continuous flow action with a hemispherical resonator [4, patent No. 2770628]. Hemispherical non-ferromagnetic resonator is docked coaxially with the cylindrical part of the hop dryer, air ducts with an electric heater are attached to its side surface. The hemispherical resonator is divided into zones by ceramic perforated biconvex baffles. At the top of the resonator, air outlets from each zone and a loading hopper are installed. A dielectric distributor is installed under the bunker. The disadvantages are the difficulty in step-by-step regulation of the heating rate and drying of freshly harvested hops.

The closest in technical essence is the known hop dryer with toroidal and astroidal resonators with energy supply in an electromagnetic field [5, patent No. 2772992]. The hop dryer contains toroidal resonators arranged in series in a vertical plane with alternating astroidal resonators with truncated tops and ceramic biconvex perforated disks in the middle.

Flaws. Such an alternation of resonators provides different rates of heating and drying of hops with a certain duty cycle of the technological process, if the layer thickness, raw material density, raw material movement speed, raw material and air heating temperature in each resonator are coordinated with high accuracy. Otherwise, it becomes difficult to maintain the temperature regime, the uniformity of drying decreases, which affects the quality of the processed hops.

An analysis of known technical solutions has shown that a technical problem in this area is the need to expand the arsenal of tools used for the staged drying of freshly harvested hops in a continuous mode while maintaining consumer properties.

The technical result of the invention is the preservation of consumer properties of hops while improving its microbiological parameters.

To solve the technical problem and achieve the claimed technical result, a tiered hop dryer with sources of dielectric and convective heating contains tiered non-ferromagnetic resonators made in the form of truncated cones with exponential generatrix and concave bases, to which concave ceramic mirrors are coaxially attached, and the diameters of the concave bases of non-ferromagnetic resonators are equal to each other and are multiples of half the wavelength, and the lengths of the resonators are different, gradually decreasing towards the lower tier, and are similarly multiples of half the wavelength, dielectric screw screws with variable pitch and diameter are coaxially located inside the resonators, connected to individual electric drives, while concave along the perimeter At the bases of the resonators with a shift of 120 degrees, waveguides with air-cooled magnetrons are placed, in addition, non-ferromagnetic air ducts from individual heat guns are connected to each resonator from the side of the concave bases, and from the side of the truncated parts of the resonators air vents are attached - transcendental waveguides, covered with non-ferromagnetic fine-mesh grids, while above the upper and under the lower resonators there are sluice gates with electric drives.

The main criteria in the design of a hop dryer with sources of dielectric and convective heating are three-stage drying of hops in a continuous-line mode of operation with different temperature conditions and different electric field strengths in the resonators and electromagnetic safety without an additional shielding case when using air-cooled magnetrons. The hop dryer contains tiered

metal-dielectric resonators in the form of truncated cones with an exponential generatrix, inside which the raw materials loaded through sluice gates are transported using screw screws with variable pitch and variable screw diameter.

The design of the resonators provides excitation of only certain types of oscillations and high electric field strength and electromagnetic safety in the continuous operation of the dryer with sources of dielectric and convective heating.

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

fig. 1 - spatial image of a tiered hop dryer with sources of dielectric and convective heating, general view;

fig. 2 - image of the technological process of the movement of raw materials through cavity resonators;

fig. 3 - spatial image of a tiered hop dryer with sources of dielectric and convective heating, a general view in section with positions;

fig. 4 - spatial image of individual elements of the first tier of the hop dryer;

fig. 5 - spatial image of individual elements of the second tier of the hop dryer;

fig. 6 is a spatial representation of individual elements of the third tier of the hop dryer.

Tiered hop dryer with sources of dielectric and convective heating contains (Fig. 1, 2):

- electric drive of the first dielectric screw 1;

- sluice gate 2 with rotary feeder electric drive and loading capacity;

- ceramic concave mirror 3 in the first resonator;

- the first non-ferromagnetic (aluminum, copper) resonator 4 with an exponential generatrix;

- air-cooled magnetrons 5 with waveguides on the first resonator 4;

- dielectric (PTFE) screw 6 inside the first resonator 4;

- non-ferromagnetic air duct 7 to the first resonator 4;

- air outlet-transcendental waveguide 8 from the first resonator, covered with a non-ferromagnetic fine mesh;

- non-ferromagnetic perforated adapter 9;

- the second non-ferromagnetic resonator 10 with an exponential generatrix;

- ceramic concave mirror 11 in the second resonator;

- non-ferromagnetic air duct 12 to the second resonator 10;

- dielectric screw 13 in the second resonator 10;

- electric drive of the second dielectric screw 14;

- magnetrons with waveguides 15 on the second resonator 10;

- air outlet-transcendental waveguide 16 from the second resonator, covered with a non-ferromagnetic fine mesh;

- non-ferromagnetic perforated adapter 17 between the second 10 and third 18 resonators;

- non-ferromagnetic third resonator 18;

- ceramic concave mirror 19 in the third resonator;

- electric drive of the third dielectric screw 20;

- non-ferromagnetic air duct 21 into the third resonator 18;

- air-cooled magnetrons 22 with waveguides on the third resonator 18;

- air outlet-transcendental waveguide, covered with non-ferromagnetic fine-meshed mesh 23 from the third resonator;

- dielectric screw 24 in the third resonator 18;

- non-ferromagnetic perforated adapter 25;

- sluice gate (rotary feeder) 26;

- electric heat guns 28 for the corresponding resonators 4, 10, 18.

Tiered hop dryer with sources of dielectric and convective heating is assembled from three tiered sections (Fig. 1-5). Each tier (Fig. 3, 4, 5) consists of a non-ferromagnetic resonator (4, 10, 18) in the form of a truncated cone with an exponential generatrix and a concave base of large diameter, on which a ceramic concave mirror (3, 11, 19) is coaxially attached. Moreover, the diameters of the concave bases of all resonators are equal to each other and are multiples of half the wavelength, and the lengths of each resonator are different, but multiples of half the wavelength. The length of the resonator of the second tier is less than the resonator of the first tier, but more than the length of the resonator of the third tier.

Each resonator is truncated at the level of the critical section, at a considerable distance from the tops of the cone, practically without disturbing the structure of the electromagnetic field, and this allows you to create holes for the movement of raw materials into another resonator through the appropriate adapters. The dimensions of the resonators are chosen in such a way that cutoff conditions arise in the tapering parts for higher types of wave oscillations. As a result, in the resonators of such a design, conditions are created for the occurrence of resonant oscillations due to re-reflections of higher-order electromagnetic waves from the critical sections [6]. The diameters of the concave bases of the resonators are equal to each other and are multiples of half the wavelength. The lengths of the resonators are reduced in tiers, but are multiples of half the wavelength, i.e. the shortest resonator length is the third tier resonator.

Inside each non-ferromagnetic resonator, dielectric screw screws (6, 13, 24) with electric drives (1, 14, 20) are installed coaxially. Along the perimeter of each concave base of non-ferromagnetic resonators (4, 10, 18) with a shift of 120 degrees, waveguides with air-cooled magnetrons (5, 15, 22) are installed. The receiving container with a sluice gate 2 made of non-ferromagnetic material is installed on the first resonator 4 from the side of the concave base. The non-ferromagnetic sluice 26 for unloading is installed under the third resonator in the non-ferromagnetic adapter 25. There are non-ferromagnetic adapters (9, 17) between the non-ferromagnetic resonators (4, 10, 18). Non-ferromagnetic air ducts (7, 12, 21) from individual heat guns (28) are connected to each resonator from the side of the concave base. From the side of the truncated part of the resonators, air vents are attached - transcendental waveguides (8, 16, 23) closed with non-ferromagnetic fine-meshed grids. The length of the second resonator is greater than the third, but less than the first resonator. The cross section of each resonator varies exponentially. Moreover, the value of the exponent of the second resonator is greater than the first resonator, but less than the third resonator. The exponents of the generating resonators in each tier are higher than the previous resonator. The hop dryer is equipped with control and measuring equipment, sensors for humidity and temperature of air and raw materials, including a device for controlling the power of the radiation flux. Permissible radiation power is 10 μW/cm ² , if it is exceeded, the duration of the work of the maintenance personnel should be reduced.

Studies have shown that the dryer should ensure the gradual removal of moisture from hop cones located in tiered resonators, for example, in three resonators 4, 10, 18. The first stage of drying is carried out at an electric field strength of 0.8-1.0 kV/cm and temperature drying agent 31-35°C. The second drying stage occurs at an electric field strength of 1.0-1.5 kV/cm and a drying agent temperature of 37-46°C, the third drying stage occurs at an electric field strength of 1.5-2.2 kV/cm and a drying agent temperature 65-75°C. To implement such a technological drying regime, the following control possibilities are provided:

- the duration of heating in each resonator by changing the rotational speed of the corresponding electric motors (1, 14, 20);

- performance and power of the heating elements (TEH) of the respective heat guns 28;

- the volume of loading of raw materials into the resonator with a change in the rotational speed of rotary feeders of sluice gates 2, 26;

- power of microwave generators 5, 15, 22.

- specific power of the generator, as the ratio of the power of the generators to the volume of loading of raw materials into the resonator, etc.

The corresponding high electric field strength in each resonator is provided due to the interference of concentrated coherent waves from ceramic mirrors, which have a small value of the dielectric loss tangent, and also due to an exponential decrease in the cross section of each resonator, but with different values of the exponent.

Technological process of drying freshly harvested hops.

Turn on all electric heat guns 28 for the appropriate performance and power of the heating elements.

Turn on the electric drives of the augers in the following sequence: third 20 (lower), second 14, first (upper) 1 augers. The rotational speed of each motor-reducer is different, within the range of 0.25-1 rpm, depending on the tier. Ensure the temperature of the drying air at the first stage of drying is not more than 31-35°C. Load the loading container with freshly harvested hops and turn on the sluice gate 2, which provides a metered supply of raw materials to the first resonator 4. After the raw material begins to move inside the first resonator 4 using the first dielectric screw 6, turn on the magnetrons 5 of the first resonator to excite an electromagnetic field of microwave frequency in it (EMSHF). Waves due to the concave ceramic mirror 3 are concentrated, and the raw material in the process of moving along the resonator is exposed to EMSHF. Under the influence of EMSHF, hop cones are endogenously heated evenly over the entire cross section, since the depth of wave penetration is commensurate with the size of hop cones. Due to the fact that the pitch of the screw is different and less than two depths of penetration of the wave (5-6 cm) into the hops, therefore, the raw material is compacted and evenly heated in thickness. In the process of moving along the resonator 4 with the help of screw turns with variable diameter and pitch, the endogenously heated hop cones are blown with warm air coming through the air duct 7 from the corresponding heat gun 28. Due to the fact that during dielectric heating, temperature, humidity and pressure gradients are directed with center to the periphery of the cones, so the released moisture from the surface is removed by air.

The exhausted moist air leaves through the air duct-excessive waveguide 8 and through the perforation of the adapter 9. The speed of movement of the raw material through the resonator, therefore, the duration of exposure to EMSHF is controlled by the rotational speed of the electric motor 1. Then the heated raw material to the required temperature wakes up through the perforated adapter 9, where there is no radiation, so as the resonator is truncated at the level of the critical section, therefore, the waves are reflected from the surface and directed inside the resonator. The critical section depends on the length of the resonator and the exponent (tilt angle) of the generatrix. The exponent of the second resonator is higher than that of the first, so the critical section of the second resonator will be at the level of a shorter length, i.e. the length of the second resonator is less than the length of the first resonator, but greater than the length of the third resonator.

Further, the raw material through the adapter 9 enters the second resonator 10, is captured using the screw 13, and then the generators 15 should be turned on on the second resonator 10. The rotational speed of the screw 13 is less than that of the screw 1. raw material at the end of the screw reaches up to 46°C. After the partially dried hop cones through the perforated adapter 17 enter the third resonator 18, the generators 22 should be turned on. rotary feeder 26 (sluice) into the receiving tank 27.

In this resonator, the electric field strength reaches up to 1.5 - 2.2 kV/cm, the heating temperature of the raw material reaches up to 65-75°C.

In perforated adapters 9, 17, 25, humidity and temperature are equalized along the cross section of hop cones.

The dryer provides gradual removal of moisture from hop cones, when moving through tiered resonators 4, 10, 18. The pressure of the supplied air is controlled and regulated depending on the humidity of the hops by changing the power of the generators and heating elements, as well as changing the speed of the electric drives of the augers. Subject to efficient modes of heating hop cones at different speeds in tiered resonators, where an electric field of different strengths is excited, hop drying occurs in a sparing mode, while maintaining consumer characteristics and improving microbiological indicators. Sluice gates, air vents - transcendental waveguides and the correct choice of the critical section on the resonator provide electromagnetic safety without an additional shielding housing. Ceramic concave mirrors reduce energy loss.

The conditions of heat and mass transfer when blowing with warm air depends primarily on the parameters of the coolant: temperature, speed and relative humidity.

The use of ceramic concave mirrors (spherical mirror - converging mirror) as part of the resonators allows you to maintain free electromagnetic oscillations of various types. Ceramics has low thermal losses, since the dielectric loss tangent is only 3-10°, therefore, the intrinsic quality factor of all designed resonators is higher than without ceramic mirrors. The concentration of the energy of the electromagnetic field in the volume of the resonator and the reduction of radiation losses is achieved through the use of ceramic concave mirrors [7].

The hop dryer should be located in a separate room, fenced off with a non-ferromagnetic grid and have a remote control.

The proposed hop dryer ensures the preservation of consumer properties of hops while improving its microbiological parameters.

Information sources:

1. Decree No. 738-r on approval of the Concept for the Development of Hop Growing in the Chuvash Republic for 2020-2025. [Electronic resource]. Access mode: km.cap.ru>doc/laws/2020/08/20/disposal-738-r.

2. Egorov V.N. Microwave dielectric resonators in physical measurements. Abstract dis. doc. Physics and Mathematics, 01.04.01 - Instruments and methods of experimental physics. Irkutsk: FSUE VNIIFTRI, 2013, 40 p.

3. Patent No. 2772987 RF, IPC C12C 3/02; F26B3. Multicavity hop dryer with energy supply in an electromagnetic field / 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. Timiryazev (RU). No. 2021132821 dated 11/11/2021. Bull. No. 16 dated 05.30.2022.

4. Patent No. 2770628 RF, C12C 3/02; F26B3. Microwave-convective continuous-flow hop dryer with a hemispherical resonator / Prosviryakova M.V., Storchevoy V.F., Goryacheva N.G., Novikova G.V., Mikhailova O.V., Ziganshin B.G. / applicant and patent holder NGIEU (RU). No. 2021136688 dated 12/13/2021. Bull. No. I dated 19.04.2022.

5. Patent No. 2772992 RF, С12СЗ/02; F26B3. Hop dryer with toroidal and astroidal resonators with energy supply in an electromagnetic field / Prosviryakova M.V., Storchevoy V.F., Goryacheva N.G., Novikova G.V., Mikhailova O.V., Ziganshin B.G. / applicant and patent holder NGIEU (RU). No. 2021135280 dated 12/01/2021. Bull. No. 16 dated 05/30/2022.

6. Drobakhin O.O. Investigation of the possibility of using coupled biconical resonators to determine the parameters of dielectric materials /O.O. Drobakhin, D.Yu. Saltykov // Applied Radioelectronics, 2014, Volume 13, No. 1. pp. 64-68.

7. Dielectric resonators. Edited by M.E. Ilchenko. M.: Radio communication, 1989. 328 p.

Claims (1)

Tiered hop dryer with sources of dielectric and convective heating, characterized in that it contains tiered non-ferromagnetic resonators, made in the form of truncated cones with exponential generatrix and concave bases, to which concave ceramic mirrors are coaxially attached, and the diameters of the concave bases of non-ferromagnetic resonators are equal to each other and multiples of half the wavelength, and the lengths of the resonators are different, gradually decreasing towards the lower tier, and are similarly multiples of half the wavelength, dielectric screw screws with individual electric drives are coaxially located inside the resonators, while along the perimeter of the concave bases of the resonators with a shift of 120 degrees, waveguides with air magnetrons are placed. cooling, in addition to each resonator from the side of the concave bases, non-ferromagnetic air ducts from individual heat guns are connected, and from the side of the truncated parts of the resonators, air vents are attached - transcendental waveguides covered with non-ferromagnetic fine mesh grids, while sluice gates with electric drives are installed above the upper and lower resonators.

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