RU2435644C2 - Device for grain heating - Google Patents

Abstract

FIELD: processing procedures.

SUBSTANCE: invention refers to process of drying loose grain materials with utilisation of hot air and it can be implemented in agriculture for grain drying. The device for grain drying consists of a chamber of a shaft type, of a rotor set on it, of loading and unloading devices, and also of arranged in tiers elements displacing grain. The device is equipped with a system for supply of heat carrier. The elements displacing grain are of a disk shape and have stepped external surface. The elements are made rotating and stationary. Also, a rotating and a stationary element form a pair and face each other with concave surfaces. Diametre of the stationary element is bigger, than diametre of rotating element. The rotating element can be secured on the rotor, while the stationary ones - on walls of the chamber. Rotating and stationary elements can be made with utilisation of anti-burning material. Each disk element can be equipped with scrapes for removal of grain. Also, the device can have a window for a visual control.

EFFECT: significant reduction of power expenditures for grain heating due to increased surface of heating and grain loosening.

5 cl, 6 dwg

Description

The invention relates to techniques for drying bulk granular materials using hot air and can be used in the field of agriculture for drying grain.

One of the main stages in post-harvest grain processing is drying. It allows you to keep the grain quality for a long time. The use of high-performance dryers significantly reduces the time for preparing grain for long-term storage, reduces grain losses in the field during the harvest period, and also allows the process of transferring grain from the field to a long-term storage warehouse to be carried out in a fairly short time and with minimal losses. There are various methods for drying grain. Basically, these are methods based on increasing the temperature of grain.

They differ mainly in terms of the transfer of heat to the grain and the removal of moisture from it and the nature of the medium. Heat can be transferred to the grain by contact, i.e. the contact of grain with the heated surface of various drying ovens, heated air or a mixture of air with flue gases, called a gas mixture.

In the first case, the air, in contact with the heated grain, takes away part of the heat from it and simultaneously absorbs moisture evaporating from the grain.

Drying with heated air can be represented in such a simple scheme:

atmospheric air containing a known amount of moisture is heated by a heater and increases the moisture capacity. Then, acting under the influence of artificial draft in the drying chamber, the heated air heats the grain and at the same time absorbs the moisture released from it. With reduced temperature and high humidity (relative and absolute), air is removed from the dryer.

When drying grain with a gas mixture, 2-2.5 times less fuel is consumed than when drying with heated air, and therefore it is most widely used. Currently, almost all domestic dryers operate on a gas mixture.

To maintain the quality of grain during artificial drying, the maximum temperature of the air or gas mixture entering the drying chamber, the maximum temperature of the heated grain and the drying time are important.

In dryers with uniform movement of the coolant and intensive mixing of the grain, you can increase the temperature and speed of movement of the coolant (air or gas mixture).

Three groups of factors affect the drying efficiency of heated air:

1) environmental conditions;

2) the type of culture being dried;

3) the design of the dryer and its operation.

The most widely used grain elevators are grain dryers developed by the All-Union Thermotechnical Institute and conventionally designated VTI (see Internet resource http://www.bibliotekar.ru/spravochnik-44/index.htm . Agricultural buildings and structures. Grain dryers). Mines consist of drying and cooling chambers. The height of the drying chamber is divided into two zones corresponding to the drying steps, in each of which the coolant (gas mixture) is supplied by separate fans with different temperatures. The inlet and outlet ducts are arranged through one in horizontal rows. Gates are installed under the drying and cooling chambers. Grain drying and cooling occur in one unit. A disadvantage of the known grain dryers is the restriction on the type of grain, because only drying of food and feed grain is possible. The grain dryer does not have a flexible technological scheme that allows drying of grain, depending on the initial moisture content of raw grain.

According to expert estimates, in the elevator industry of the Russian Federation, 75% of grain dryers are outdated, have outdated technological systems, become fire hazardous and require replacement.

A known installation for drying granular materials in a fluidized bed containing a housing, a gas distribution sectional grill, between the sections of which are installed heating elements made in the form of vertical longitudinal ribs and connected, like sections of the gas distribution grill, to a current source (see patent No. 779769, IPC : F26B 17/26, F26B 3/34, published November 15, 1980) [1].

However, in this installation, heating elements made in the form of vertical longitudinal ribs, when immersed in a grain layer, do not provide a convective supply to the processed material of an air heat flow that has a conveying effect, since they are not washed by the heat carrier, but only conductive heating is carried out, which reduces drying intensity.

Known recirculation dryers (see. "Grain dryers stationary mine grades of chipboard". Internet resource http://www.kmz.pl.ua/products.php?cat=26 ), designed for drying all types of grain, oilseeds and other food crops appointments with different initial humidity. In a recirculating grain dryer, part of the dried grain is mixed with raw grain, so that the grain of any initial moisture content is dried to dry state in one pass. The higher the moisture content of raw grain, the less it is fed to the dryer and the more dry recycle grain is added to it. Recirculation dryers do not require the selection of batches of grain by moisture. Thanks to contact moisture exchange and repeated circulation of grain, its moisture is leveled. Known, for example, a mine recirculation grain dryer according to patent No. 2142103 [2]. The dryer contains parallel recirculation and drying-cooling shafts. A heating chamber and a heat and mass exchanger are installed above the mines. To implement flexible, interchangeable drying schemes for grain of various quality, the heat and mass exchanger above the shafts is equipped with a vertical partition with a bypass window dividing it into two parts, with a heating chamber installed on one above the recirculation shafts and an additional vertical partition with an adjustable damper in the other above the drying and cooling shafts a bypass window located below the bypass window in the first partition.

The closest in design features to the claimed invention is a device for heating grain according to patent No. 2351861, IPC F26B 17/12, F26B 23/04, published April 10, 2009) [3], selected for the prototype. The known device contains a shaft with inlet and outlet pipelines. In the mine, heating elements are arranged in a tiered fashion, made in the form of flat multi-electrode composite electric heaters installed in the mine with support elements, with the possibility of rotation about a horizontal axis and equipped with a mechanism for their rotation, each flat multi-electrode composite electric heater is enclosed in a wear-resistant heat-conducting shell. The presence of a rotation mechanism allows you to change the speed of movement of grain in the mine and provide the ability to control the heating of grain in a wide temperature range. However, in the known device, heat is transferred to the grain only by a contact method, i.e. contact of grain with the heated surface of the heating elements.

The disadvantage of this device is the high energy costs for electric heaters, as well as the fact that this design provides only conductive heating, that is, the drying of the material occurs through heat transfer, only from the heated surface, which reduces the drying efficiency.

The technical result achieved by the claimed invention is to increase the efficiency of the drying process by increasing the heating surface and loosening the grain, reducing energy consumption for heating the grain, increasing the operational reliability of the device.

The technical result is achieved due to the fact that the device for heating grain contains a shaft-type chamber, a rotor installed in it, loading and unloading devices and belt-mounted grain-moving elements, while it is equipped with a coolant supply system, the grain-moving elements have a plate shape and a step external (external) surface and are made both rotating and stationary, moreover, the rotating and stationary elements form a pair and face each other with concave surfaces, while the stationary element is made with a diameter larger than the diameter of the rotating element.

In this case, the rotating elements are fixed on the rotor, and the fixed ones are on the walls of the shaft-type chamber.

While rotating and stationary elements are made using non-stick material.

Moreover, each plate element is equipped with scrapers for removing grain.

In this case, the device is equipped with a window for visual inspection.

The list of drawings illustrating the claimed invention.

Figure 1 - diagram of a device for heating grain;

figure 2 - arrangement of plate elements 5 and 6;

figure 3 - diagram of the rotating element 5;

Figa - top view of the rotating element 5;

4 is a diagram of a fixed element 6;

figa is a top view of a stationary element 6;

5 is a diagram of the movement of the drying agent (hot air);

6 is a diagram of the movement of grain in the elements 5, 6.

A device for heating grain contains a chamber 1 of a shaft type with a system for loading and unloading of dried material and a system for supplying and discharging a heat carrier (Fig. 1), placed in a housing 2.

On top of the housing 2 of the device is a loading hopper 8. Below is a funnel 9 of the discharge hopper. Air ducts 10 and 11 are installed on the sides of the housing 2 of the device to remove excess moisture. The chamber 1 through the duct 14 is connected to a heat generator 12, equipped with a radial fan 13.

In the center of the chamber 1, a vertical rotor 3 is installed, rotating from an electric drive 4.

Rotating grain moving elements 5 are fixed on rotor 3. Fixed elements 6 are fixed inside on the walls of chamber 2. Rotating 5 and stationary 6 moving elements are installed in pairs (Fig. 2). The pairs of elements 5 and 6 are arranged in tiers along the entire height of the chamber 1. Elements 5, 6 have a plate shape, face each other with concave surfaces, and the diameter of the lower fixed plate exceeds the diameter of the upper rotating plate (figure 2).

The outer surfaces of the plate elements 5 and 6 are made stepped to increase the surface of the heat transfer (figure 3, 4). In this case, the plate elements 5 and 6 can be made of non-stick material, for example, food-grade silicone, or have a non-stick coating.

On each disk element 5, 6, scrapers 7 for removing grain are installed from below (FIGS. 3, 4).

The camera 1 is equipped with a window 16 for visual inspection made of heat-resistant glass (figure 5).

A device for heating grain can be equipped with a remote control system for the temperature of the dried material and coolant, as well as the upper and lower levels of the dried material.

The process of heating the grain is as follows.

Hot air (drying agent) through the fan 13 through the heat generator 12 is pumped into the chamber 1 (directed upward), where convective heating of the grain and removal of excess moisture through the ducts 10, 11. The direction of the air flow and its temperature schedule provide drying of grain in three conditional thermal zones - from lower air temperatures in the third zone to higher in the first zone (figure 5).

The grain is continuously fed into the loading hopper 8 and then by gravity (top to bottom) into the chamber 1. Here the grain is heated not only by contact with the heated air, but also by heat transfer from the elements 5, 6 heated by the hot air. When the grain comes into contact with the surfaces of the elements 5 and 6, conductive heating occurs.

Getting on the stepped outer surface of the rotating elements 5, the grain under the action of centripetal forces, moving along the steps, gets into the plate of the lower stationary element 6, the diameter of which is larger than the diameter of the upper plate. Under the influence of the temperature of the drying agent, moisture is first removed from the grain surface, then internal moisture moves from the core to the periphery. Under the action of the heat carrier flow passing through the grain layer, the grains intensively move one relative to another, the grain is in motion, which creates a “fluidized bed” effect in plate 6. In the fluidized bed, close contact is achieved between the granular material and the coolant, which ensures uniform heating and drying of the grain. The effect of a fluidized bed is achieved by a small layer height (up to 50 mm) with constant loosening of grain. The height of the layer is regulated by scrapers 7 mounted on each element 5, 6 from the bottom (Fig 3, 4).

Passing through the belly-located dish-shaped elements 5, 6 (Fig. 6), the grain heats up, falling down the chambers, the grain is unloaded through the discharge hopper 9 and goes further along the technological chain of the grain drying complex.

The implementation of the plate-shaped elements 5, 6 with a stepped surface significantly increases the heating surface, which can significantly reduce energy consumption for heating grain. The implementation of the surface of the plate elements 5, 6 of non-stick material prevents sticking and burning of grain to the surfaces, helps to increase the efficiency of the device.

The average duration of the grain in the drying chamber under the influence of a drying agent is from 7 to 17 minutes and is set by the operator depending on the culture and humidity of the initial grain mass.

The maximum temperature of the heated air (coolant) t max = 180 degrees.

Stepless regulation of the rotor speed of the dryer (from 8 to 30 revolutions per minute) and a wide range of temperature settings for the heat generator allow you to adjust the drying process for various crops.

The camera provides visual control through heat-resistant glass for the mechanical movement of the grain mass and the rotating parts of the device.

The inventive device for heating grain will find application in the composition of seed cleaning and drying lines and other complexes when working with grain of high harvesting humidity.

INFORMATION SOURCES.

1. Patent No. 779769, Installation for drying granular materials in a fluidized bed, published November 15, 1980

2. Patent No. 2142103. Mine recirculation grain dryer. Published: 11/27/1999.

3. Patent No. 2351861, A device for heating grain, published April 10, 2009 - the closest analogue.

Claims (5)

1. A device for heating grain, containing a shaft-type chamber, a rotor installed in it, loading and unloading devices and belt-mounted grain-moving elements, characterized in that it is equipped with a coolant supply system, the grain-moving elements have a plate shape and a stepped outer surface and are made both rotating and stationary, moreover, the rotating and stationary elements form a pair and face each other with concave surfaces, while the stationary element is made with etrom larger than the diameter of the rotating member. 2. The device for heating grain according to claim 1, characterized in that the rotating elements are fixed on the rotor, and the stationary ones on the walls of the shaft chamber type. 3. The device for heating grain according to claim 1, characterized in that the rotating and stationary elements are made using non-stick material. 4. The device for heating grain according to claim 1, characterized in that each plate element is equipped with scrapers for removing grain. 5. The device for heating grain according to claim 1, characterized in that it is equipped with a window for visual inspection.

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