RU2406952C1 - Cyclic dryer for seeds and grains - Google Patents

Abstract

FIELD: agriculture. ^ SUBSTANCE: for heating and cooling air supplied to the bins using a vortex tube connected with its outputs with bins through the devices of switching flows of heated and cooled air, and a source of compressed air is used as an air pump, in the form of a compressor or a blower, at that the pressurised air from the source is fed to the dryer and then into the vortex tube, where it is divided into hot and cold flows, at that the cold air flow is used to achieve the effect of final cooling of the product before unloading, and the coolant temperature is regulated by air supply injected into the vortex tube. ^ EFFECT: invention enables to use one device for heating and cooling of air supplied for drying and regulate the duration of cycles of heating and cooling of products along with simple design. ^ 2 cl, 1 dwg

Description

The invention relates to agricultural production, in particular to drying seeds and grain (food and feed), and can also be used in forestry and food industry, both in large farms of industrial type, and in private and private farms with limited production volumes, as well as during busy periods of harvesting and part-time work of grain.

Known mobile grain dryer ZSPZH-8, having two drying shafts, divided into drying and cooling zones, in which three fans supply heated from the furnace and the external cooled air. The grain of the mine is loaded with a conveyor belt, the firebox runs on liquid fuel (see Yukish A.E. “A Guide to the Equipment of Elevators and Warehouses,” 2nd ed. - M .: Kolos, 1978, p. 161-164) .

Some of the drawbacks of such a dryer include the complexity of the design (three fans and a liquid-fuel firebox), the additional need for electricity to drive the fans, and the fire hazard of the design.

Also known is the “Rotary dryer for seeds and grain”, in which one of the three units is equipped with a cooling chamber, and the exhaust pipe of the sedimentary chamber is connected via chokes to the fan of the furnace device and the heat exchanger of the dryer, and during cooling the grain is cleaned of impurities (see RF Patent No. 2219447, F26В 15/04, Published on December 20, 2003. Bull. No. 35).

The disadvantages of such a dryer include the large dimensions and the presence of two types of energy carriers when it is impossible to change the duration of the heating and cooling cycles of the grain, depending on the speed of the dryer carousel.

Also known is the “Cyclic Dryer for Bulk Materials”, in which one blower fan and electric air heating are used, and the cooling cycles take place during the free fall of the product through partitions in drying columns of adjustable height (see RF Patent No. 2082924, F26В 17/10, Publ. June 27, 1997 Bul. No. 18). With a somewhat simplified design of such a dryer, the number of heating-cooling cycles is regulated only constructively - by the number of sections, which makes it difficult to adjust and reconfigure the dryer during operation.

The objective of the invention is to develop a cyclic dryer for seeds and grain, using one device for heating and cooling the air supplied to the dryer and allowing you to adjust (change) the duration of the heating and cooling cycles of the product with the simplicity of design, which does not require special training for personnel and is completely fireproof, and the dryer is possible in both mobile and stationary versions with a serial design of an air blower.

The problem is solved in that in a cyclic dryer as a single device for heating and cooling the drying agent - air, use a vortex tube connected to its outputs with bunkers through a device for switching flows of heated and cooled air, moreover, obtained using one vortex tube, heated and cooled air flows into the respective bins with the product, while two cycles occur simultaneously in the dryer: heating the product in one hopper and cooling in another hopper, with the possibility of exclusion of cycles without stopping the air injection, and the drying process is based on the displacement of moisture from the body of the product with its active ventilation due to the movement of moisture from the zone with higher humidity to the zone with lower humidity (occurs both at the heating stage and at the deposition stage) and due to the movement of moisture from the warmer to the less heated zone (occurs at the cooling stage, when the heated product is blown by a cold stream of air).

For the operation of the vortex tube, a source of compressed air (compressor or blower) is used, while the dryer design has a desiccant air dryer installed in front of the entrance to the vortex tube, where it is divided into heated and cooled flows, and pre-dried air (heated or chilled), which allows to intensify the drying process of the product, and the cold air flow is used to achieve the effect of the final cooling of the product before unloading, the coolant temperature is controlled supply of air injected into the vortex tube. The dehumidifier used can be either refrigerated type, or based on the second vortex tube. The latter is simple and cheap in design, has no moving parts, does not require any maintenance and does not contain environmentally, chemically dangerous and toxic substances. In this regard, the use of a desiccant based on a vortex tube in the composition of the proposed dryer may be preferable.

The vortex tube was originally created as a device for cooling or heating the supplied gas. The design of the vortex tube is quite simple, devoid of moving parts. For the operation of the vortex tube, it is necessary to provide only a supply of compressed air. With various designs of vortex tubes, the required inlet gas pressure can range from 0.6 atm to tens, and the temperature difference at the outlet is from -20 ° C at the cold end to 200 ° C at the hot end.

In a vortex tube based. on the Rank-Hills effect (vortex effect), there is a separation of the swirling flow of gas supplied to the pipe into two. One of the flows (near-axis) has a temperature below the incoming stream, and the other (peripheral) is higher.

The vortex tube in its main initial version contains a housing with an energy separation chamber, a nozzle central gas flow inlet, a diaphragm, a throttle device and pipes for the removal of cold or hot flow (see, for example, A.V. Martynov, V.M. Brodyansky “ What is a vortex tube ”, M., Energy, 1976, p.6 and 7). The diaphragm and the cold flow outlet pipe are located on the “cold” end of the vortex tube, i.e. on the installation side of the nozzle input. Accordingly, the throttle device and the heated flow outlet pipe are located at the opposite “hot” end of the vortex tube.

Vortex tubes in modern technology are used to a limited extent in air cooling systems of electronics, in air curtains at fixed workplaces in metallurgy and galvanic shops, and in means of individual thermal protection. Narrowly specialized eddy tubes in single quantities are used in the aerospace industry, in medicine for local cooling of the body surface during operations, in energy, metallurgy, shipbuilding and ship repair, chemical and gas industry for heat-protective equipment of workers, repairmen, builders, etc. (see, for example, A.D.Suslov et al. “Vortex Devices”, Moscow, 1985, pp. 31-33; Sh.A. Piralishvili et al., “Vortex Effect, Experiment, Theory, Technical decisions ", M., Publishing House of the UNTsP Energomash, 2000, pp. 41-42).

Typically, a vortex tube uses only one outlet (cold or hot), which somewhat reduces its efficiency, inhibiting widespread use.

Previously, the use of a vortex tube for drying grain with adjustable and variable heating-cooling cycles and the use of both waste streams (cold and hot) in agriculture from public sources is unknown.

The drawing shows a schematic diagram of a cyclic dryer of seeds and grain based on a vortex tube.

The loop dryer includes:

1. Compressed air source (compressor)

2. Air dryer

3. Vortex tube

four; 5; 6; 7 switching cranes

8. The first bunker

9. The second bunker.

A cyclic dryer operates as follows.

Compressed air from source 1 (compressor or blower) enters air dryer 2, where moisture is removed. Drained air enters the vortex tube 3, connected by its outputs to the bins 8 and 9 through the device for switching the flow of heated and cooled air. In the vortex tube, there is a separation of the dried air into heated and cooled flows. The heated air stream enters in particular into the first hopper 8, and the cooled stream into the second hopper 9, while the switching valves 4 and 6 are open, and the valves 5 and 7 are closed. The air entering the first hopper 8 blows out the entire product layer and is discharged into the atmosphere through special purge windows. In the hopper 8, the product warms up and in parallel its preliminary drying. In the second hopper 9, the product heated from the previous cycle is dried and cooled (if necessary, the temperature of the heat carrier can reach -20 ° C and below), and the cold air flow is used to achieve the effect of the final cooling of the product before unloading, and the temperature of the heat carrier is regulated by the flow air injected into the vortex tube 3. After the cooling process is completed, the product is unloaded from the second hopper 9 and the next batch is loaded into it. Next, redirected heated and cooled flows between the first and second bins by closing the taps 4 and 6 and opening the taps 5 and 7.

In the design of the dryer, an additional hopper can be provided to ensure the continuity of the drying process: while the other two bins are vented with cold and hot air flows, in the third one the product is loaded (unloaded).

Depending on the size of the dryer and its degree of automation, several options for its execution are possible:

- with manual or mechanized processes of loading and unloading the product from the drying bins of the first 8 and second 9;

- with reverse air flow from the vortex tube by taps or valves with servo-controlled switching;

- with an additional unit for automated control and monitoring of parameters.

The novelty of the dryer is that the proposed dryer does not contain any chemically hazardous and ozone-depleting substances (such as freon, ammonia, etc.) for cooling the supplied air. As a refrigerant and a coolant, dried compressed air passing through a vortex tube is used. If a compressor or an electric blower is used as a source of compressed air, then emissions of pollutants, carbon dioxide, etc. into the atmosphere are completely eliminated.

Unlike dryers in which heating is carried out by flue gases, drying with clean air using a heat and cold generator in the form of a single vortex tube maintains the quality of the product and ensures complete fire and explosion safety, as this eliminates direct contact of flue gases (and sparks) with the product. In the proposed dryer, there is no open flame at all, and the temperature of the drying agent at the entrance to the hoppers does not exceed the set values, due to the peculiarities of the vortex tube, which sharply distinguishes the proposed dryer from analogues, since the possibility of overheating or supercooling of the product is excluded.

The design of the vortex tube in the proposed dryer is able to provide a temperature of the cold air stream much lower than the ambient temperature (to -20 ° C), which reduces the required number of heating-cooling cycles to achieve the final moisture of the product, compared to dryers where the cooling is carried out with atmospheric air. This circumstance is especially relevant for areas with a hot climate, where ambient temperatures can be kept at 30 ° C or more. A decrease in the number of heating-cooling cycles leads to a reduction in energy costs, due to the lack of repeated processes of heating and cooling the product; to reduce the total drying time, which means that the productivity of the dryer increases.

In the proposed dryer, the product at the outlet has a temperature below ambient air, which increases its stability during storage. In air-cooled dryers, more time is required to cool the product, which reduces their productivity.

The temperatures of the hot and cold ends of the vortex tube, as well as their performance, can be controlled by the air supply from the compressor, depending on the set drying conditions. The temperature of the hungry air stream at the exit of the vortex tube can be adjusted so that the effect of the final cooling of the product is achieved.

An unobvious effect of the proposed cyclic dryer in a mobile version may be the possibility of its use directly in the field during peak periods of harvesting and part-time work.

The proposed dryer consists of functional independent units that are joined together by standard elements. At the time of preservation (storage), the installation can be easily dismantled for ease of storage and transportation. Units such as a source of compressed air (compressor or blower), a vortex tube (together with a source of compressed air) can be used for other purposes. For example, a source of compressed air - for powering pneumatic devices, a vortex tube with a source of compressed air: “cold end” - for cooling, freezing food, conditioning rooms in warehouses, warehouses, etc .; “Hot end” - warming machinery, equipment in the winter season, defrosting and cleaning from ice, space heating, etc .; active ventilation bins - for storing dried product.

Claims (2)

1. A cyclic dryer of grain and seeds, including hoppers for the product with grain loading and unloading devices, a single supply and distribution device for heated and cooled air in the hoppers, characterized in that a vortex tube connected to its outlets is used to heat and cool the air supplied to the hoppers with bunkers through devices for switching the flow of heated and cooled air, and a compressed air source in the form of a compressor or blower is used as an air blower. 2. The cyclic dryer of seeds and grain according to claim 1, characterized in that the injected air from the source is supplied to the dryer, and then to the vortex tube, where it is divided into heated and cooled streams, and the cold air stream is used to achieve the effect of final cooling product before unloading, while the temperature of the coolant is regulated by the flow of air pumped into the vortex tube.