RU118834U1 - BLINDS - Google Patents

Abstract

1. Louvered sieve containing rotary flaps installed in the frame with upper and lower working surfaces located on the sides of the pivot axis, the upper working surface is made with a flat comb along the longitudinal edge and teeth located between the comb petals with a grooved cross-sectional shape, curved from the plane combs down and facing the convexity of the cross-section towards the lower working surface, made with through grooves opposite the mentioned teeth and with a bend along the longitudinal line downward relative to the plane of the comb, characterized in that the through grooves are made with an expansion directed from the bottom of the groove to its outlet, when this, the teeth are made with a decrease in width from the base to the end of the tooth. ! 2. A sieve according to claim 1, characterized in that the through grooves are made in the form of a trapezoid, the smaller base of which forms the bottom of the groove. ! 3. A sieve according to claim 1, characterized in that the flap is formed from a sheet blank made along one longitudinal edge with projections in the form of segments alternating with tongue protrusions made with a narrowing from the base to the end, while along the other longitudinal edge of the blank opposite reed projections are formed through grooves in the form of a trapezoid, the smaller base of which forms the bottom of the groove. ! 4. A sieve according to claim 3, characterized in that the tongue projection is made in the form of a triangle with a rounded apex at the end of the projection. ! 5. A sieve according to claim 3, characterized in that the tongue protrusion is made in the form of a trapezoid, the larger base of which is located at the base of the protrusion. ! 6. A sieve according to claim 1, characterized in that the comb petals are made in the form

Description

The technical field to which the utility model relates.

The utility model relates to agricultural engineering and can be used in cleaning systems of combine harvesters and stationary grain cleaning machines.

State of the art

A standard louvre sieve of a combine harvester is known, which contains a frame in which rotary plates — shutters of the blinds, with two working surfaces located on the sides of the rotation axis are successively mounted on parallel axes. The upper working surface has a ridge profile or comb along the longitudinal edge. The lower working surface - called the "skirt", performs the function of taking part of the air flow from the total emitted by the fan, and its direction along the sash surface upwards to the heap of the separated threshed mass (Prince S. A. Alferov. Air-lattice cleaning of combine harvesters, M .: Agropromizdat, 1987, p. 19). The design of the louvre shutter with a continuous skirt and the elongated domed shape of the comb petals contribute to the rapid attenuation of the air flow from the fan, which leads to inefficient use of the sieve area, and the formation of vortices around the comb, resulting in an air plug and threshed mass coming out from under drum, blown back, instead of lying flat on the sieve. In addition, the straw mass freely flies between the combs, clogging the separated grain.

A solution is known in which, for intensification of the air flow, the upper and lower surfaces of the valves are made with alternating sizes, and the valves are installed with alternating steps on crankshaft axes of different heights (see patent SU No. 1655346, IPC: A01F 12/44, publ. 15.06 .91 g.).

A solution is known in which the problem of increasing the separation efficiency and sieve throughput is solved by separately performing and securing the upper and lower parts of the sash, in order to be able to control the air flow direction (see patent SU No. 829033, IPC: A01F 12/44, publ. 15.05 .81g).

As the closest, by the presence of similar structural features, analogue to the claimed solution, a constructive solution of the louvre sieve was adopted (see patent for invention RU 2397634, IPC: A01F 12/44, A01D 41/12, published on 08.27.2010). According to the aforementioned patent, the louvre sieve contains a frame in which pivoting plates are installed - sashes having upper and lower working surfaces located on the sides of the pivot axis. The upper working surface is made with a flat comb along the longitudinal edge and teeth located between the petals of the comb with a grooved cross-sectional shape. The teeth are bent downward from the plane of the comb so that the convexity of the cross section is directed towards the lower working surface, in which through grooves are made opposite the said teeth, and the lower working surface itself is bent downward along the longitudinal plane of the comb.

One drawback of this solution is the inefficient use of the air flow, which attenuates before reaching the remote edge of the sieve, due to the shape of the through channels formed by the grooves in the skirts of the wings, as well as the shape of the curved teeth.

Another disadvantage is the fairly frequent damage to the teeth of the valves, occurring when the tooth is displaced from its normal central position. As a result of this displacement, the tooth abuts against the wall of the groove and, upon further closing the sieve, bends, preventing further complete closing of the sieve.

Utility Model Disclosure

The task to which the claimed utility model is directed is to increase the reliability and efficiency of the sieve.

The technical result achieved by using the claimed utility model is to improve the aerodynamic characteristics of the sieve, which ensures more efficient use of the fan air flow and increase the working surface of the sieve. Another positive result is the possibility of self-centering of the tooth in the through groove when closing the sieve.

The aforementioned problem has been solved, and the technical results have been achieved in the design of the louvre sieve, comprising pivoting flaps installed in the frame with upper and lower working surfaces located on the sides of the rotation axis, of which the upper working surface is made with a flat comb along the longitudinal edge and located between the petals of the comb teeth with a grooved cross-sectional shape, curved downward from the plane of the comb and convex to the side of the lower working surface awns formed with through slots in front of said teeth and with the longitudinal limb with respect to the downlink comb plane.

New in the design of the inventive sieve is the implementation of through grooves with an extension directed from the bottom of the groove to its exit, as well as the implementation of curved teeth of the upper working surface with a decrease in width from the base to the end of the tooth.

Under the "upper and lower working surface" refers to the parts of the sash located on the sides of the axis of rotation.

In the prototype solution, the through groove is a slit, a rectangular cut, made from the edge deep into the sash plate. In the claimed solution, the groove walls are located to each other at an angle, the opening of which is directed to the edge of the sash. Thus, the narrowest part of the groove is located at the bottom, and the widest at the edge of the sash plate, at the exit of the groove.

The proposed shape of the through grooves (notches) made in the lower part of the sash, expanding to the edge of the sash, provides the best conditions for the passage of the air flow created by the cleaning fan. The range of the air flow increases, provides a longer preservation of the power of the flow during its movement along the sieve.

The narrowing of the groove from the bottom up to its bottom, which is located as a result of the installation of the sash in the sieve frame above, contributes to the additional orientation of the air taken by this sash upward along the sash.

The shape of the curved fluted teeth of the sash, having a large width at the base and narrowing towards the end, provides an increase in the speed of air jets coming out from under the comb washing the end part of the tooth, compared with the speed of the air currents enveloping the tooth at its base. As a result of such a difference in the speeds of the air flows coming out from under the comb, a difference in the vacuum of air is created at the base of the tooth and at its end part, which leads to the formation of a funnel in the recess of the tooth gutter at its base. A relatively heavy grain is drawn into this funnel, which slides along the gutter under the sieve, while light straw particles of the heap and floor are blown away.

At the same time, blowing is of better quality, due to the high speed of air flows, which meet less resistance of pointed teeth.

The formation of more powerful jets of air rising upward along the sash and coming out from under the comb provides, on the one hand, a larger rise of the grain to be cleaned above the sieve, and on the other hand, it can increase the range of its movement along the sieve in the “flight phase”, t. e. finding the heap in suspension. The result is a more effective separation of the straw-grain mass, a decrease in the density of the heap per unit area of the sieve, which contributes to a better separation of the straw particles.

Thus, the combination of such essential features as: the shape of the through grooves expanding to the exit, the grooved shape of the teeth facing the convexity of the cross section to the air flow and the implementation of the teeth narrowing from the base to the end, provide a redistribution and a certain organization of air flow, which leads to improvement aerodynamic characteristics of the louvre sieve. As a result, the possibility of a longer, without attenuation, propagation of the air flow along the sieve is provided, the duration of the flight phase of the divided mass of grain heap over the sieve increases, and the conditions for the formation of an aerodynamic funnel, which contributes to a better separation of the straw-grain mass, are provided. As a result, the quality of cleaning increases, the productivity of the sieve in the same area increases, the percentage of hammering decreases.

The pointed shape of the tooth helps to pierce the clogging of the groove when closing the sash. Moreover, even if the tooth has shifted from its normal position in the center of the groove, and when the sieve is closed, it abuts against the wall of the through groove, the shape of the tooth, characterized by the relative position of the side walls at an angle to each other, due to the narrowing of the width of the tooth from its base to the end, ensures that the tooth under the influence of the walls of the groove will still move to its central position. Thus, the shape of the tooth and the shape of the through groove of the sash leaf, in the aggregate, provide another positive result, namely, self-centering of the tooth in the through groove when closing the sieve, which eliminates the possibility of bending or damage to the teeth of the sash that occurs in the prototype solution.

The technical results obtained are valid for both the upper and lower grain sieve.

The form of the concrete implementation of the through grooves is not limited, the main thing is to comply with the conditions for expanding the groove to the exit. The walls of the groove can be made both in a straight line and in a curved shape. However, the trapezoidal shape is the most technologically advanced and effective form of performing through grooves.

In a preferred embodiment of the device, the through grooves are made in the form of an isosceles trapezoid, the smaller base of which forms the bottom of the groove.

The shutter of the louvre sieve is made of sheet blanks, plates. On one longitudinal edge of the workpiece, ridges of the comb are formed, preferably in the form of segments, alternating with reed ridges tapering towards the end. Reed ledges have the form of triangles or trapezoids. In the first case, the top of the triangle, forming the end of the protrusion, is rounded in radius. In the case of a trapezoidal shape of the reed protrusion, the larger base of the trapezoid forms the base of the protrusion. Through the second longitudinal edge of the workpiece opposite the reed ridges, through grooves are formed in the form of a trapezoid, the smaller base of which forms the bottom of the groove.

All corners in the workpiece are preferably rounded, which is necessary in order to ensure the safety of further operation of the louvre sieve.

In preferred specific cases of the device, the distinguishing features are also aimed at improving aerodynamic performance:

- the petals of the comb are made in the form of segments;

- in the middle part of the leaf a longitudinal zig is made for placement on the axis of rotation;

- the longitudinal bending line of the lower surface is located at a distance less than the depth of the through groove;

- the teeth are bent in an arc with the center lying on the lower working surface, lower from the axis of rotation of the sash.

Brief Description of the Drawings

Figure 1 - louvre sieve, General view;

Figure 2 is a view A from figure 1, a top view, fragment, sieve in the "closed position";

Figure 3 is a view B from figure 1, shows the shutter of the louvre sieve, bottom view;

Figure 4 is a section B-B of figure 3, a side view of the sash with a side view;

Figure 5 - section C-C of figure 4 is enlarged, shows a cross section of the tooth;

In Fig.6 (a and b) - options for sheet blanks for the manufacture of the sash;

In Fig.7 is a graph of the dependence of the height of the flight of the grain heap on the range of its movement.

Utility Model Implementation

The louvre sieve made according to the claimed invention contains pivoting flaps 3 installed in the frame 1 on the longitudinal axes 2 (see Figs. 1, 2).

The axis of rotation 2 is fixed in the middle part of the leaf 3 so that two working surfaces 4 and 5 are formed on its sides. The surface 4 of the rotary leaf 3 in any position of the sieve, from “closed” to “fully open”, is located above the axis of rotation, therefore called the "upper" work surface. The surface 5 of the sash 3 is always below the axis, therefore it is called the “bottom”.

Sash 3, shown in Fig.3-5, contains a longitudinal ridge 6 in the middle part to accommodate the axis 2. On the upper working surface 4 along the longitudinal edge there is a flat comb 7 with petals in the form of segments, between which there are teeth 8 with a grooved cross shape sections.

The teeth 8 are made with decreasing width from the base to the end of the tooth, are bent from the plane of the comb 7 downwards and face with a convexity of the cross section towards the lower working surface 5, on which through the grooves 9 are formed through the grooves 9 of a trapezoidal shape. The edge of the working surface 5 is bent downward relative to the plane of the comb 7 along a longitudinal line 10 located from this edge at a distance less than the depth of the groove 9. The angle of the bend is 40-50 °.

The manufacture of the shutter of the blinds can be carried out by known methods on known equipment, for example using dies, allowing cutting and bending. The manufacture of the shutter shutter is as follows.

Flat strip is cut out from a strip of sheet material (see Fig. 6). In the process of such cutting, a comb 7 is formed immediately with petals in the form of segments, through grooves 9 and reed ledges 11.

On figa shows the implementation of the reed protrusions 11 with a triangular shape, the apex of the triangle forming the end of the protrusion is rounded radius. On figb shows the implementation of the reed tabs 11 with a trapezoidal shape, the larger base of the trapezoid is located at the base of the protrusion, and the smaller is the end of the protrusion. In Fig. 6a and b, the dotted lines also show the possible shapes of the grooves 9 allowed by the present invention.

The billet is bent, as a result of which the longitudinal ridge 6 is formed, the longitudinal edge is bent with through grooves 9, as well as the profiling of the tongue protrusions 11 with the formation of a grooved cross-sectional shape. Then carry out the bending of the protrusions 11 of the workpiece from the plane of the comb 7 along an arc of a circle with a center lying on the lower working surface 5. In this case, the convexity 12 of the cross section of the tooth 8 is turned towards the opposite groove 9.

The axis 2 is placed in the recess of the ridge 6 of the sash and fix it. The sash 3 is installed in the sieve frame 1 at an appropriate distance from each other, allowing the entry of the curved teeth 8 of one sash into the corresponding grooves 9 of the adjacent one (see Fig. 2).

The work of the louvre sieve is as follows.

The threshed mass coming out from under the threshing drum is discharged onto the sieve, where it, under the action of gravity, oscillatory movements of the sieves and the air flow created by the fan 13, is separated: the grain, which has a higher specific gravity, falls through the holes of the sieve down into the hopper for grain collection, and the rest of the straw mass is carried out by the flow of air.

The main flow P _{1 of} air produced by the fan 13 (see Fig. 1) is distributed along the sieve through the channels organized by a set of through grooves 9 of the leaves 3. The shape of the grooves 9, made with the extension to the edge of the leaf, provides better conditions for the passage of the flow and its spread along the sieve.

Some part of the air flow P _{2 is} cut off by the solid part of the skirt 5 of the sash 3 and is directed upwards along it. Moreover, the shape of the through groove 9 contributes to the additional orientation of the air drawn by this leaf up and its direction along the leaf 3, the flat and smooth surfaces of which: the shape of the petals of the comb 7 and the streamlined shape of the teeth 8, eliminates the appearance of turbulences of air at the exit from the comb. Air calmly flows around the obstacle on both sides, connecting behind the tooth, forming a reinforced upward jet, which, like a needle, flashes the mass located at this moment above the sieve, providing enhanced loosening of the grain heap.

The air flows washing the end of the narrower part of the tooth have a speed V ₂ greater than the speed V _{1 of the} air flows enveloping the tooth at its base. The resulting difference in the suction of air created at the base of the tooth and at its end part leads to the formation of a funnel 14 in the recess of the tooth groove at its base, into which relatively heavy grain is drawn, and lighter straw particles of the heap and floor blow off further along the sieve. Figure 1 shows the formation of a funnel only at the first sash 3 sieve. Similarly, the process occurs in each tooth of all wings, with a gradual decrease in flow rates, as you move away from the fan.

The formation of powerful jets of air rising along the sash up and coming out from under the comb ensures the lifting of the cleaned grain heap above the sieve and allows you to increase the range of its movement along the sieve in suspension, the so-called phase of the "flight". In Fig.7, which shows a graph of the dependence of the height of the flight of the grain heap on the distance of its movement along the sieve, a thin line 15 shows the "phase of flight" of the grain heap that occurs when using the prototype louvre sieve. The main line 16 shows the "phase of flight" of the grain heap when using the inventive louvered sieve. The flight phase when using the inventive louvre sieve is much larger in height and longer, practically along the entire sieve. As a result of a longer stay of the heap in suspension, an effective separation of the straw-grain mass occurs, a decrease in its specific density and distribution over the entire area of the sieve, which contributes to better separation of straw particles, more efficient work of the sieve.

The pointed shape of the tooth 8 provides a piercing of the resulting “straw plugs” of the through groove 9, into which the tooth enters when closing the sieve. If the tooth is displaced from its normal position in the center of the groove, the tooth 8 that rests on the wall of the groove 9 is pushed out by the side walls of the groove to its center. As a result, bending or damage to the teeth of the sash 8 is excluded, which increases the reliability of the device.

Claims (8)

1. A louvre sieve containing pivoting flaps installed in the frame with upper and lower working surfaces located on the sides of the axis of rotation, the upper working surface is made with a flat comb along the longitudinal edge and the teeth are located between the petals of the comb with a grooved cross-sectional shape, curved from the plane combs down and convex cross section in the direction of the lower working surface, made with through grooves opposite the said teeth and with a bend along the longitudinal l downward relative to the plane of the comb, characterized in that the through grooves are made with an extension directed from the bottom of the groove to its exit, while the teeth are made with decreasing width from the base to the end of the tooth. 2. The sieve according to claim 1, characterized in that the through grooves are made in the form of a trapezoid, the smaller base of which forms the bottom of the groove. 3. The sieve according to claim 1, characterized in that the sash is formed from a sheet blank made on one longitudinal edge with protrusions in the form of segments, alternating with reed protrusions made with narrowing from the base to the end, while on the other longitudinal edge of the blank recessed protrusions formed through the grooves in the form of a trapezoid, the smaller base of which forms the bottom of the groove. 4. The sieve according to claim 3, characterized in that the reed protrusion is made in the form of a triangle with a rounded apex at the end of the protrusion. 5. The sieve according to claim 3, characterized in that the reed protrusion is made in the form of a trapezoid, the larger base of which is located at the base of the protrusion. 6. The sieve according to claim 1, characterized in that the petals of the comb are made in the form of segments. 7. The sieve according to claim 1, characterized in that the longitudinal line of the limb of the lower surface is located from its longitudinal edge at a distance less than the depth of the through groove. 8. The sieve according to claim 1, characterized in that the teeth are curved in an arc with the center lying on the lower working surface, lower from the axis of rotation of the sash.