RU198376U1 - BLIND BED FOR DRYING BULK MATERIALS - Google Patents

Abstract

The utility model relates to devices for drying bulk heat-resistant materials, for example, cereals and legumes, and can be used in direct-flow conveyor-type dryers with active ventilation. Louvered bed for drying bulk materials contains a group of identical corner elements fixed relative to each other. The first shelves of corner elements are located in parallel with an overlap and with a clearance t in height, forming the working surface of the inclined bed. The second shelves are directed downward from the first. The angle between the flanges of the corner elements exceeds the straight line by the angle α. The louvered bed contains inclined longitudinal elements in the form of girders, equipped with metal strips with evenly spaced slots. Second shelves of corner elements are fixed in the slots of the raspor. On the first flanges in the overlap zone with a width b, projections are made to provide a predetermined clearance height between adjacent first flanges. It is proposed that the angle between the shelves of the corner elements be made greater than the straight line by the value of the angle α such that α = arctan t / (B-b), where α is the angle between the edge of the metal strip and the first shelves. The technical result consists in increasing the reliability of the device by reducing the overvoltage in the corner elements, when installed with an interference fit during the assembly of the louvered bed, while reducing heat losses by reducing aerodynamic resistance. 1 h. p. f-ly, 3 ill.

Description

The invention relates to devices for drying bulk heat-resistant materials, for example, cereals and legumes, and can be used in direct-flow conveyor-type dryers with active ventilation.

Direct-flow dryers, having such advantages as simplicity of design, ease of use, and the ability to manufacture from available materials, at the same time provide more gentle drying modes and reduce the high humidity of the seeds to conditional in one pass. In such installations, it is necessary to reduce the resistance of the air distribution system to the air flow so that air freely passes through the openings of the louvre bed and is evenly distributed in the grain embankment without the formation of stagnant zones in the lower layers that impair the quality of seed drying. Therefore, the optimization of the parameters of the gas distribution louvre bed is an urgent task. To determine the design parameters of all elements of the louvre bed, it is necessary to consider the entire aerodynamic system that forms the air flow in the louvre bed, including the shape, length and width of the channels for the passage of air flows.

A tilted louvre bed of a closed plate conveyor is known, described in a dryer according to GB patent No. 704996 with a priority of June 26, 1951. The conveyor is a chain conveyor with a working part length of about 60 feet (18288 mm), and the return section of the conveyor passes more or less horizontally above the base of the front end of the device, from where it then rises relatively steeply to a height of about 7 feet (2134 mm), after which it lowers (this is its working part) with a slight tilt (about 6 degrees) to the rear end of the device. The fan is located mainly under the steeply rising front end of the conveyor and is adapted for suction of air in the axial direction (across the movement of the conveyor) and for its tangential supply to the channel from which it can pass through the working part of the conveyor to its upper side. A closed plate conveyor moves the drained material at a convenient speed. In the upper working part of the conveyor, heated air is supplied from below by a fan passing through the drained material. The working upper part of the conveyor is inclined to the level at which the dried material is delivered, that is, the conveyor feed of the material is supplemented by gravity. For grain, seeds, and similar materials, plates are overlapped in the working part of the conveyor, creating a surface along which material can be moved along the conveyor. The plates are arranged in a row, preferably overlapping (Figure 5 of GB Patent No. 704996) so that the final edge of each plate is overlapped by the initial edge of the subsequent plate by a small amount, on the order of 1/8 or 3/16 of an inch (overlap area 3.175-4.76 mm) . The final edge of each plate is provided with protrusions on which the corresponding initial edge of the subsequent plate rests to form gaps, i.e. narrow slots directly in the layer of the working part of the conveyor, which are directed towards the air flow from the fan. The plates are made in the form of inclined wide shelves of corner elements having a width in the direction of movement of about 3 or 4 inches (76.2-101.6 mm), so that the transverse slots are respectively distributed along the length of the conveyor under its working part. The height of the slots (gaps) depends on the height of the protrusions on the plates, as is clearly shown in Figure 5. From Figure 5 it can be seen that the shelves of the corner elements are approximately half as wide as the wide shelves and are directed vertically downward, forming a right angle with the wide shelves .

The first disadvantage of the above louvre bed is the increased aerodynamic resistance of the channel for the passage of air flow between the shelves in the mating zone of the shelves of the corner element, due to the fact that the angle between the shelves of the corner elements is made straight. Because of this, part of the air flow in the joint zone of the shelves is reflected from the surface of the shelves, which creates a large aerodynamic drag, which leads to an increase in heat loss and a decrease in the quality of drying. In addition, the height of the gap between the wide shelves affects the overall inclination of the entire louvre bed, which leads to an unreasonable increase in the size of the dryer at small angles of inclination of the louvre bed.

The second drawback is that the overlap (overlap) of the corner elements is only 1/8 or 3/16 of an inch (overlap zone 3.175-4.76 mm), that is, it is quite small, which can cause deterioration in the quality of drying due to spillage of agricultural material under the working part. In addition, the absence of structural elements that ensure the installation of corner elements with equal pitch and clearance reduces the stability of the structural parameters of the channels for the passage of air flows, which negatively affects the aerodynamic characteristics of the louvre bed.

Also known is the inclined louvre bed according to the patent for utility model RU No. 182685 with a priority of October 24, 2017, selected as the closest analogue. The louvre bed for drying bulk materials contains a series of identical corner elements fixed to each other, the first shelves of which are parallel overlapped with the overlap and with the gap between the shelves, forming the working surface of the inclined bed, and the second shelves are directed downward from the first. The bed contains oblique longitudinal elements in the form of runs, equipped with metal strips with evenly spaced slots, in which the second shelves of the corner elements are fastened. The strips are attached to the sides of each of the runs, while the slots of the strips are made at right angles to the upper edge of the runs. On the first shelves in the area of overlap (overlap) protrusions are made to provide a given gap between the first shelves. The angle between the shelves of the corner elements is made to exceed the straight line by an angle α, the value of which is determined by the height t of the protrusion and the width of the first shelf.

In this louvered bed, the channels for the passage of air flow have greater stability of parameters due to the fixing of the lower shelves of the corner elements at a time in special strips with slots.

In addition, the louvre bed has lower aerodynamic drag in the joint zone of the shelves, since the angle between the shelves exceeds the straight line by the angle α, which contributes to the redirection of the air flow to the drying zone and, thereby, reduces heat loss and energy consumption for drying.

However, the angle α, determined by the height t of the protrusion and the width B of the first shelf, provides reliable fastening of the corner element opposite only for the case when the overlap zone is small and does not exceed 10 mm. At the same time, calculations and practice show that the optimal overlap value, which on the one hand provides minimal aerodynamic resistance to air flow, and on the other hand ensures guaranteed non-spillage of the product under the louvre bed, is in the range of 30-50 mm. Therefore, the execution of the angle between the shelves without taking into account the overlap zone leads to an unjustified decrease in this parameter, which causes overvoltages in the corner elements when they are installed with an interference fit in the slotted plates during the assembly of the louvre bed.

The utility model is aimed at solving the problem of improving the reliability of the device by reducing the overvoltage in the corner elements when they are installed with an interference fit during the assembly of the louvre bed while reducing heat loss by reducing aerodynamic drag.

The essence of the utility model is that in a louvre bed for drying bulk materials containing a group of identical corner elements fixed to each other, the first shelves of which are parallel to the overlap and with a clearance t in height, forming the working surface of the inclined bed, and the second shelves are directed down from the first and the angle between the shelves of the corner elements exceeds the straight line by the value of the angle α, while the louvre bed contains oblique longitudinal elements in the form of runs, equipped with metal strips with evenly spaced slots, in which the second shelves of the corner elements are fastened, and on the first shelves in Overlaps with a width of b have ledges made to provide a given clearance height t between adjacent first shelves, it is proposed that the angle between the shelves of the corner elements be greater than the straight line by the angle α = arctan t / (Bb), where α is the angle between the edge of the metal strip and the first shelves .

The angle between the shelves of the corner elements can be made to exceed the straight line by the value of the angle α, equal, mainly, 1-5 ° a.

The implementation of the angle between the shelves of the corner elements exceeding the straight line by the angle α = arctan t / (Bb), that is, taking into account the overlap zone allows you to provide the specified distance t between the wide shelves in height without overvoltage in the corner elements during assembly of the louvre bed, which increases reliability work louvre bed.

In addition, the execution of the angle between the shelves of the corner elements, taking into account the width of the overlap zone, leads to a decrease in aerodynamic drag in the joint zone of the shelves of the corner elements due to a decrease in the reflected heat carrier flow, therefore, leads to a decrease in heat losses and a decrease in energy consumption for drying.

The implementation of the angle between the shelves of the corner elements exceeding the straight line by an angle α equal to, mainly, 1-5 ° allows you to get the most optimal size t of the gap between the first shelves without spilling bulk materials and unjustified narrowing of the air channel.

The figure 1 shows a fragment of a louvered bed for drying bulk materials, a longitudinal section, where:

1 - corner element;

2 - the first shelf of the corner element;

3 - the second shelf of the corner element;

4 - strip with slots;

5 - run;

6 - ledge.

The figure 2 shows the remote element A in figure 1. In figure 3 shows the louvre bed, a top view.

The louvre bed (figures 1, 2) is intended for use in direct-flow conveyor-type dryers and contains a series of identical corner elements 1 fixed in the slots of strips 4 on the runs 5. The first shelves 2 of the corner elements 1 are parallel to the lap and with a clearance t in height. In each corner element 1, the first shelf 2 is wider than the second shelf 3 in width, the angle δ between the shelves 2, 3 exceeds the straight line by the angle α and is equal to 91 ° -95 °. The shelves 3 of the corner elements 1 are installed at an angle of 90 ° to the edge of the strips 4 in the evenly spaced slots of the metal strips 4. The strips 4 are based on the runs 5, which are inclined and set the slope of the entire louvre bed. The angle of inclination of the louvre bed is determined by both the angle of repose of the drained product and the overall dimensions of the dryer, such as its height and length.

Along each first shelf 2, a series of protrusions 6 are made with a regular pitch T (Fig. 3). The protrusions 6 are located in the overlap zone of adjacent corner elements 1 and are designed to support the first flange 2 of the adjacent corner element 1, which ensures fixation of a predetermined gap t between the overlapping first flanges 2 regardless of the weight of the material. When installing the corner elements 1 at a time and with an interference fit in the slots of the strip 4 as a result of elastic deformation, the second shelves 3 are securely fixed in the corresponding slots of the metal strip 4.

In FIG. 2 shows the triangle MNK, including the angle α between the edge of the metal strip 4 and the shelf 2, which is rectangular, since the triangle MNK is a straight line in construction since the perpendicular to the segment MN is restored from point K. The shelves 2 are parallel to each other, the segment MN is an adjacent leg, with MN = (B-b), and the segment NK is an opposite leg, with NK = t, therefore, α = arctan t / (B-b). The presence of technological errors in the implementation of the corner elements 1, such as the radius of the rounding of the corner of the corner element, surface irregularities of the shelf caused by the stamping of the protrusions, if necessary, can be taken into account in each specific case of the device.

The distance between the second shelves 3 within 70-90 mm allows you to optimize the ratio of such parameters of the louvre bed as the overlap and the number of corner elements, with a decrease in which there is an increase in air mass pressure in the system, an increase in the speed of passage of air mass in the drying zone and an improvement in aerodynamics.

The height of the gap t between the first shelves 2 is from 2 to 6 mm and is determined by the type of bulk heat-resistant materials, in particular grain size.

The width of the first shelves 2 of the corner elements 1 in the range of 100-140 mm allows for optimal drying quality and sufficient load capacity of the louvre bed. The width of the second shelves 3 of the corner elements 1 in the range of 24-28 mm allows for sufficient bending strength of the corner element.

The protrusions on the first shelves 2 of the corner elements 1 are made in a row with a step T across the movement of the bulk material in a checkerboard pattern with a shift in the adjacent corner elements 1 by a value of T / 2, which eliminates non-blown zones, which positively affects the drying of bulk heat-resistant materials for due to even distribution of air flow.

The values of the angle α are preferably in the range of 1 ° -5 °. This is due, firstly, to the fact that the angle α is limited by the angle of inclination of the louvered bed, approximately equal to 6 °, due to the size of the dryer. Secondly, this is determined by the structural dimensions of the louvre bed - width B of the first shelf 2, equal to 100-140 mm, width b of the overlap zone, 30-50 mm, height t of the gap between the shelves 2, 2-6 mm. So, for example, with (B-b) = 70 mm and a change in the value of t from 2 to 6 mm, the angle α is in the range from 1 ° to 5 °. With (B-b) = 90 mm and a change in the value of t from 2 to 6 mm, the angle α is also in the range from 1 ° to 5 °. A dimension t of more than 6 mm will lead to spillage of bulk materials, and less than 2 mm to an unjustified narrowing of the air channel and an increase in heat loss, therefore, the angle α in the range from 1 ° to 5 ° is most preferable.

The height of the gap t (the height of the protrusion 6 of the corner element 1) and the distance T between the protrusions 6 (Fig. 1, 2) are calculated taking into account the dependence on the performance of the fans of hot and cold air flows of the dryer. The protrusions on the first shelves 2 of the corner elements 1 are arranged in a row with a step T across the movement of the bulk material. Behind the protrusions 6 on the corner elements 1 zones are formed that are not blown by hot and cold flows, which adversely affects the quality of drying. To eliminate not blown zones, the protrusions of 6 adjacent corner elements 1 are shifted by T / 2, that is, they are staggered, then on the next corner element 1 this zone will be blown. A fragment of the louvre bed with the layout of the protrusions is shown in FIG. 3.

The device operates as follows.

On the louvre bed, bulk material for drying is supplied from above. The layer of dried bulk product is transported, for example, by means of a conveyor (not shown in the figures) down the slope of the louvre bed to the discharge side. From under the louvre bed from below through the gap t between the first shelves 2 of the corner element 1, a hot air stream under pressure penetrates the bulk product (not shown in the figures) and, passing through the gaps between the grains, carries away excess moisture, while the bulk product is in motion mixes, including under the influence of pressure of a hot stream. The increase in the angle δ between the shelves of the corner element 1 due to the angle α between the first shelves 2 and the edge of the metal strip 4, increases the reliability of the device and improves the aerodynamic properties by redirecting the air flow to the drying zone.

Thus, the proposed utility model allows to increase the reliability of the device by reducing the overvoltage in the corner elements when they are installed with an interference fit during the assembly of the louvered bed while reducing heat loss by reducing aerodynamic drag.

Claims (2)

1. The louvre bed for drying bulk materials containing a group of identical corner elements fixed relative to each other, the first shelves of which are parallel to the overlap and with a clearance t in height, forming the working surface of the inclined louvre bed, and the second shelves are directed down from the first, and the angle between shelves of the corner elements exceeds the straight line by the angle α, while the louvre bed contains oblique longitudinal elements in the form of runs, equipped with metal strips with evenly spaced slots, in which the second shelves of the corner elements are fastened, and on the first shelves in the overlap zone with width b protrusions are made to provide a given clearance height t between adjacent first shelves, characterized in that the angle between the shelves of the corner elements is made to exceed the straight line by the angle α such that α = arctg t / (Bb), where α is the angle between the edge of the metal strip and first shelf. 2. The louvre bed for drying bulk materials according to claim 1, characterized in that the angle between the shelves of the corner elements is made to exceed the straight line by an angle α equal to, mainly, 1-5 °.

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