RU2800591C1 - Rotary microwave convection hop dryer - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: invention can be used in hop farms for drying freshly harvested hops. The rotary microwave-convective hop dryer contains shielding cylindrical non-ferromagnetic housings 1 located vertically, inside which, coaxially and in tiers, between stationary perforated non-ferromagnetic bases 7, 11, 15, non-ferromagnetic perforated rotors 4, 8, 12 with radial ceramic perforated partitions 6, 10, 14 are located. In each rotor, the outer and inner non-ferromagnetic perforated shells form an annular space. Rotors with fixed non-ferromagnetic bases form coaxial resonators. The loading of raw materials into the compartments formed between the radial ceramic partitions occurs through sector cuts in the non-ferromagnetic bases of each coaxial resonator. Along the perimeter of the outer shells of the rotors there are crowns 20, 22, 24 for engagement with the drive gears on the shaft of the motor-reducers located outside the hop dryer. Non-ferromagnetic electrically driven spiral screws 3, 17 are located in the loading non-ferromagnetic tanks. The emitters from the air-cooled magnetrons 18, 26 are directed to the respective annular spaces through the waveguides. A non-ferromagnetic air duct 19, 21, 23 with a heat gun is connected to each tier of the working chamber through the shielding body. Perforated inner non-ferromagnetic shells form an air outlet 25.

EFFECT: invention will make it possible to preserve the consumer properties of dried and disinfected hops in the process of staged microwave convective drying.

1 cl, 10 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.

It is known that the preservation of consumer properties of dried hops, such as: golden-green color; aroma; light yellow lupulin; the absence of crumpled cones (no more than 5%) is possible with a combined endogenous-convective drying method in working chambers - cavity resonators of non-standard designs with air-cooled magnetrons that provide a continuous drying mode [1].

Scientific innovation idea implementation of this drying method lies in the fact that the working chamber is made in the form of tiered rotors with perforated ceramic compartments located between stationary non-ferromagnetic bases, forming coaxial resonators in which a traveling wave is excited from three microwave generators.

Known microwave convective hop dryer continuous-flow action with tiered resonators in the form of hemispheres and ellipsoid (patent No. 2774961) [1].

Flaws. In this hop dryer, there are difficulties in coordinating technological parameters with each other, namely, layer thickness, density and speed of movement of raw materials, heating temperatures of raw materials and air in each resonator. Therefore, it is difficult to gradually adjust the heating and drying rate of freshly harvested hops.

The closest in technical essence is the well-known carousel extractor of one and two tiered versions [3, pp. 274-278]. This is a cylindrical device with a perforated stationary bottom, over which a rotor with radial baffles moves. The main parts of the rotor are the inner and outer shells, forming an annular space, which is divided by radial partitions. In cross section, each radial partition has a downwardly tapering shape.

Some components of the developed rotary microwave convective hop dryer are similar to those of a carousel extractor [2].

The development of a rotary microwave-convective continuous-flow hop dryer with tiered working chambers for step-by-step drying of freshly harvested hops, which makes it possible to dry hop cones in an efficient mode under the conditions of hop-growing farms while maintaining its consumer properties, at reduced operating costs, is relevant.

The technical result of the invention is the preservation of consumer properties of dried and disinfected hops in the process of phased microwave convective drying in different modes, in a working chamber formed from non-ferromagnetic rotors with radial ceramic compartments arranged in tiers between stationary perforated non-ferromagnetic bases.

To solve a technical problem and achieve the claimed technical result, a rotary microwave convective hop dryer contains

shielding cylindrical non-ferromagnetic housings located vertically, inside which coaxially and in tiers, between stationary non-ferromagnetic bases, non-ferromagnetic perforated rotors with radial ceramic perforated baffles are located, the cross section of which has a shape tapering downwards, where the chord distance between the baffles is not more than two wave penetration depths,

moreover, in each rotor, the outer and inner non-ferromagnetic perforated shells form an annular space, and the rotors with stationary non-ferromagnetic bases form coaxial resonators,

at the same time, in the non-ferromagnetic loading tank located on the upper non-ferromagnetic stationary base of the resonator of the first tier, above the sector cut, and in the receiving non-ferromagnetic tank located under the sector cut of the lower stationary non-ferromagnetic base of the third tier resonator, electric-driven spiral screws are installed,

moreover, along the perimeter of the outer perforated shells of the rotors, gear rims are located for engagement with the drive gears on the shaft of the motor-reducers located outside the hop dryer,

while the emitters from the air-cooled magnetrons located with a shift of 120 degrees on the upper base of the resonator of the first tier and under the lower base of the resonator of the third tier are directed to the corresponding annular spaces through the waveguides, and the rotor of the second tier is located between the stationary perforated non-ferromagnetic bases,

at the same time, non-ferromagnetic air ducts from the heat gun are connected to each rotor through shielding housings, and perforated inner non-ferromagnetic shells form an air vent.

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

- spatial image of a rotary microwave-convective hop dryer (general view), (Fig. 1);

- spatial image of a rotary microwave-convective hop dryer (general view in section), (Fig. 2);

- spatial image of a rotary microwave-convective hop dryer (general view in section, with positions), (Fig. 3);

− spatial image of a perforated rotor with perforated ceramic baffles and a crown on the outer shell (Fig. 4);

- spatial image of a ceramic perforated radial partition (Fig. 5);

- spatial image of a non-ferromagnetic housing of one tier with a cutout for the drive gear (Fig. 6);

- spatial image of a non-perforated base with a sector cut (Fig. 7);

- spatial image of a perforated base with a sector cut (Fig. 8);

− spatial image of a ring gear with an electric drive gear (Fig. 9);

− electrically driven non-ferromagnetic spiral auger − retarding system (Fig. 10).

Rotary microwave convective hop dryer contains (Fig. 1-10):

- non-ferromagnetic cylindrical shielding housings 1;

- stationary non-ferromagnetic bases 2, 7, 11, 15 with sector cutouts;

- non-ferromagnetic loading capacity with an electrically driven non-ferromagnetic spiral screw 3;

- tiered non-ferromagnetic rotors 4, 8, 12;

- compartments 5, 9, 13 formed by perforated ceramic radial partitions 6, 10, 14;

- receiving non-ferromagnetic capacity 16;

- non-ferromagnetic electrically driven spiral auger 17 for unloading dried hops;

- magnetrons 18, 26 with waveguides and fans for cooling;

- non-ferromagnetic air ducts 19, 21, 23 with heat guns of the corresponding tiers of the hop dryer;

- electric drives of the rotors (due to the clutch of the drive gear on the shaft of the gear motor with the ring gear) 20, 22, 24;

- air outlet 25 with exhaust fan.

Rotary microwave-convective hop dryer (Fig. 1-10) contains shielding cylindrical non-ferromagnetic housing 1 arranged in tiers. Inside each housing, electrically driven perforated rotors 4, 8, 12 are located coaxially and in tiers between perforated non-ferromagnetic stationary bases 2, 7, 11, 15 with sector cutouts. In each rotor, the outer and inner non-ferromagnetic perforated shells form an annular space. Rotors with fixed non-ferromagnetic bases form coaxial non-ferromagnetic perforated resonators. Each annular space is divided by vertical radial perforated ceramic baffles 6, 10, 14 into several compartments 5, 9, 13. In cross section, these ceramic baffles have a downwardly tapering shape to facilitate loading of raw materials to the lower tier or unloading into an unloading tank.

The raw material is loaded into the compartments and unloaded from the compartments through sector cuts in the bases of each resonator. The individual drive of the rotors is carried out with the help of gears with gear rims 20, 22, 24, installed on the outside, along the perimeter of the outer shell of each rotor. Due to the engagement of the drive gear on the shaft of the gear motor with the ring gear, the rotor rotates.

The technological process of drying is as follows .

Turn on heat guns to supply warm air of a certain temperature and capacity through non-ferromagnetic air ducts 10, 21, 23 to the perforated rotors of all tiers. The supply of convective heat from individual heat guns to the rotor is carried out through non-ferromagnetic air ducts directed through the shielding cylindrical housings of the hop dryer.

Turn on gear motors for rotation of non-ferromagnetic perforated rotors 4, 8, 12 due to the engagement of the drive gear on the gearbox motor shaft with gear rims 20, 22, 24 on the outer shells of the rotors.

Load freshly harvested hops (70-80% moisture) into a non-ferromagnetic receiving container with the valve closed. Open the valve and turn on the electric drive of the non-ferromagnetic spiral auger 3.

After that, freshly harvested hops are loaded into ceramic compartments 5 of the coaxial resonator of the first tier using a non-ferromagnetic spiral screw 3, which simultaneously performs the function of a slowing system, which ensures electromagnetic safety and uniform loading of compartments 5 formed by radial ceramic partitions 6. Loading raw materials into compartments formed between radial ceramic baffles occurs through sector cuts in the non-ferromagnetic bases of each coaxial resonator.

Next, turn on generators 26 (magnetrons), after which an electromagnetic field of microwave frequency (2450 MHz, 12.24 cm) is excited in the coaxial resonator of the first tier (a traveling wave is excited).

A traveling wave is excited in the coaxial resonator, which reduces the risk of breakdown at a raw material moisture content of 80% and the maximum load of the resonator. The energy spent on the polarization of the raw material is generated in the hop cones in the form of heat. A valuable property of microwave energy is the concentration in the volume of hops, the mass of which is heated selectively depending on the electrical properties of its components. The released surface moisture evaporates and is removed by convective warm air (23) outside the hop dryer through the perforation of the rotor and the air outlet 25.

In the process of moving the perforated rotor 4 of the first tier with raw materials in ceramic compartments 5 between stationary non-ferromagnetic bases from the sector cut 7, partially dehydrated and heated selectively, depending on the electrical parameters of the petals and rods, hop cones are unloaded into perforated ceramic compartments 9 of the rotor 8 of the second tier. Having made almost a full circle in the upper tier, hop cones are poured through the sector cutout from the unloaded compartment into the corresponding compartment of the coaxial resonator of the second tier. In this perforated rotor 8, warm air from a heat gun, entering through a non-ferromagnetic air duct 21, ensures the evaporation of surface moisture, and the absence of an electromagnetic field of microwave frequency in this tier helps to equalize pressure, humidity and temperature in the petals and stems of hop cones due to thermal conductivity, this allows reduce rod brittleness.

Next, the raw material through the sector cutout 11 is poured out of the rotor of the second tier into the ceramic compartments 13 of the rotor 12 of the third tier. As soon as partially dried hops appear in the compartments 13, it is necessary to turn on the microwave generators 18 (it is not allowed to turn on the microwave generators without raw materials in the resonator) to excite the EMSHF. Then, in the coaxial resonator of the third tier, the hops will be exposed to endogenous-convective heating and will dry up to a moisture content of 10-12%. Such an alternation of dielectric heating and a pause, during which the temperature, pressure, and humidity equalize over the entire cross section of the hop cones, ensures a gentle drying regime and the preservation of consumer properties of raw materials. It is expected to reduce the specific energy costs for drying hops due to the exclusion of microwave generators in the second tier and the supply of convective heat to each tier in efficient modes with three-stage drying. The destruction of the structure of the cones is minimal due to the use of spiral screws for feeding and unloading raw materials.

The movement of hop cones with the help of rotors 4, 8, 12 on stationary bases 7, 11, 15 is carried out at low speeds of the motor-reducer, which provides a gentle mode of transportation. The lower base of the third tier is not perforated, which reduces the loss of convective heat. Cylindrical non-ferromagnetic housings also reduce the loss of convective heat and provide radio tightness of the hop dryer together with spiral retarding systems 3, 17 (electrically driven spiral augers 3, 17). If the diameter of a non-ferromagnetic wire is small compared to the diameter of the spiral, then it can be considered as a cylinder, the conductivity of which is infinite in the direction of the spiral turns and is zero in the transverse direction [3]. The correct selection of the spiral radius and winding pitch can provide sufficient EMF deceleration efficiency, i.e. reduction of radiation through the loading window. Calculations show that the power of the radiation flux through the loading tank will decrease by almost 4 times if a spiral moderating system is used. In addition, freshly harvested hops have a moisture content of up to 80%, which means that the electromagnetic field closes on the raw material. Therefore, one should expect compliance with the safe norm of microwave radiation of 10 μW/ ^cm2 [4].

Management of efficient modes is facilitated by the ability to control the power of microwave generators, the rotational speed of the rotors of each tier, the volume of loading into the compartments, the performance and power of heat guns.

Perforated ceramic partitions with a cross-section tapering downwards allow the radiation energy to be concentrated in the raw material. Therefore, it will provide an electric field strength sufficient for hop disinfection (0.6-1 kV/cm). Ceramic baffles make it possible to reduce radiation losses through the perforation of the rotor shells [4, p. 359].

The quality of dried hops depends on the temperature and pressure of the supplied air, the dose of exposure to an electromagnetic field of ultrahigh frequency, and the strength of the electric field at each stage of drying. The uniform distribution of hops in the volume of the coaxial resonator and the uniformity of its heating is ensured due to the fact that the distance between the ceramic radial partitions is not more than two depths of wave penetration into the hop cones (4-5 cm).

The intrinsic quality factor of resonators with perforated ceramic baffles is higher than those with PTFE baffles; The efficiency of the hop dryer is higher. The absence of thermal inertia of microwave heating on the raw material ensures high accuracy in the control of the drying process and its reproducibility. With a decrease in the moisture content of hops during the drying process, the loss of microwave energy decreases, and heating continues only in those areas of the raw material where high humidity is still preserved.

Information sources

1. Patent No. 2774961 RF, IPC C12C3/02; F26B3. Microwave hop dryer with tiered resonators /Prosviryakova M.V., Storchevoj V.F., Goryacheva N.G., Mikhailova O.V., Novikova G.V.; applicant and patent holder RGAU-MSHA named after K.A. Timiryazev (RU). – No. 2021129382; dec. 08.10.2021 . Bull. No. 18 dated 06/24/2022.

2. Koshevoy E.P. Technological equipment for enterprises producing vegetable oils. - St. Petersburg: GIORD, 2001. 368 p.

3. Baskakov S.I. Electrodynamics of wave propagation: M.: URSS. 416 p.

4. Strekalov A.V., Strekalov Yu.A. Electromagnetic fields and waves. M.: RIOR: INFRA-M, 2014. 375 p.

Claims (1)

Rotary microwave-convective hop dryer, characterized in that it has vertically arranged screening cylindrical non-ferromagnetic housings, inside which, coaxially and in tiers, between the stationary non-ferromagnetic bases of the housings having sector cutouts, non-ferromagnetic perforated rotors with radial ceramic perforated partitions are installed, the cross section of which has a tapering from top to bottom, the distance of the chord between the ceramic partitions is not more than two depths of wave penetration, while in each rotor the outer and inner non-ferromagnetic perforated shells form an annular space, and the rotors with stationary non-ferromagnetic bases form coaxial resonators, and along the perimeter of the outer perforated shells of the rotors there are toothed rims for coupling with drive gears on the shaft of motor-reducers located outside the hop dryer, in addition, in a non-ferromagnetic loading tank located on the upper non-ferromagnetic stationary base of the resonator of the first tier, above the sector cutout, and in the receiving non-ferromagnetic tank located under the sector cutout of the lower stationary non-ferromagnetic base of the third tier resonator, electrically driven spiral screws are installed, while the emitters from the air-cooled magnetrons located with a shift of 120 degrees on the upper base of the first tier resonator and under the lower base of the third tier resonator are directed to the corresponding annular spaces through waveguides, the rotor of the second tier is located between stationary perforated non-ferromagnetic bases, non-ferromagnetic air ducts with heat guns are connected to each rotor through shielding housings, and perforated internal non-ferromagnetic shells form an air vent.