RU2834712C1 - Grain cleaning machine pneumatic system - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: proposed invention relates to machine building and can be used in agricultural production, flour-and-elevator and feedstuff industry for cleaning grain materials from light impurities. Pneumatic system of grain cleaning machine includes pneumatic separation channels of pre-sieving and post-sieving separation with devices for input of cleaned material and air discharge channels, radial fan, suction chamber, cyclone, loading device of initial material, devices for removal of cleaned grain and wastes. Pneumatic separation channel of post-sieve separation is equipped with expansion chamber and communicated with it by inlet window. Expansion chamber adjoins the pneumatic separating channel on the side of its outlet, is equipped with a curvilinear baffle plate, the upper end of which adjoins the external wall of the pneumatic separating channel outlet, and the lower one forms with the chamber wall an outlet window with depth equal to 0.4…0.5 of its length, and is located above the edge of the inlet window at a distance equal to at least two of its depths. Expansion chamber length is 4…5 depths of the inlet window. Expansion chamber depth is 1.0…1.2 of the chamber length. Depth of the inlet window is equal to the depth of the pneumatic separation channel. Air flow rate in pneumatic separation channels is controlled by throttle valves installed in air discharge channels.

EFFECT: expansion of technological capabilities of the pneumatic system – effective operation in modes of preliminary, primary and secondary cleaning at permissible losses of fodder grain to wastes and small hydraulic resistance of the expansion chamber.

4 cl, 2 dwg

Description

The proposed invention relates to mechanical engineering and can be used in agricultural production, the flour-milling and elevator industry and the feed industry for cleaning grain materials from light impurities.

A pneumatic system of a grain cleaning machine is known, containing pneumatic separating channels of pre-sieve and post-sieve separation with devices for input of the cleaned material and air exhaust channels equipped with throttle valves, a radial fan, the inlet of which is connected to the air exhaust channels by means of a suction chamber, and the outlet pipe - by means of an air duct with a cyclone, a loading device for the original material, devices for outputting cleaned grain and waste (Sychugov N.P., Sychugov Yu.V., Isupov V.I. Machines, units and complexes for post-harvest processing of grain and grass seeds / Ed. N.P. Sychugov. Kirov: publishing house OOO "VESI", 2015. - Pp. 91-94). In this pneumatic system, the grain material is processed twice - before and after the sieves, which improves the quality of cleaning.

The disadvantages of this pneumatic system are that when operating in the primary cleaning mode, the loss of wholesome and feed grain into unused waste (cyclone) increases above the standard values, and the wear of the radial fan wheel blades also increases.

The closest in technical solution and achieved result to the proposed invention is a pneumatic system of a grain cleaning machine, containing pneumatic separating channels of pre-sieve and post-sieve separation with devices for introducing the cleaned material and air discharge channels equipped with throttle valves, a radial fan, the inlet of which is connected to the air discharge channels by means of a suction chamber, and the outlet pipe - by means of an air duct with a cyclone, a loading device for the original material, devices for removing cleaned grain and waste, while the pneumatic separating channel of post-sieve separation on the side of its outlet is equipped with an expansion chamber with a rotary cover and a device for removing feed grain, wherein the rotary cover is hingedly mounted on the edge of the wall of the expansion chamber and, when closed, simultaneously serves as the inner wall of the outlet (RU Patent No. 2735076, MKI ⁷ B07B 4/00. Pneumatic system of a grain cleaning machine cars. / Burkov A.I., Glushkov A.L., Lazykin V.A. No. 2020110940; Application 03/16/2020. // Publ. 10/28/2020. Bull. No. 31 - prototype).

The presence of an expansion chamber with a rotating lid allows for efficient operation not only in the pre-cleaning mode (with the lid closed), but also in the primary cleaning mode (with the lid open) - to capture randomly released particles of forage and whole grain from the air flow.

The disadvantage of this pneumatic system is that when operating in the secondary cleaning mode, the air flow speed in the pneumatic separation channel increases to the maximum hovering speed of the feed grain particles, while the conditions for their deposition in the expansion chamber worsen, and they move together with light impurities into the waste.

The problem that needs to be solved is to expand the technological capabilities of the pneumatic system - the ability to operate efficiently in both the preliminary and primary cleaning mode, as well as secondary cleaning with acceptable losses of feed grain in waste and low hydraulic resistance of the expansion chamber.

The stated problem is solved using a pneumatic system of a grain cleaning machine comprising pneumatic separating channels of pre-sieve and post-sieve separation with devices for introducing the cleaned material and air exhaust channels equipped with throttle valves, a radial fan whose inlet opening is connected to the air exhaust channels by means of a suction chamber, and whose outlet pipe is connected by means of an air duct with a cyclone, a loading device for the initial material, devices for removing cleaned grain and waste, the pneumatic separating channel of post-sieve separation is equipped on the side of its outlet with an expansion chamber with a device for removing feed grain and is connected to it by an inlet window, wherein the expansion chamber is equipped with a curved reflective partition, the upper end of which adjoins the outer wall of the outlet of the pneumatic separating channel, and the lower end forms an outlet window with the wall of the chamber with a depth equal to 0.4 ... 0.5 of its length, and is located above the edge of the inlet window at a distance equal to at least two of its depths, the length of the expansion chamber is 4...5 depths of the inlet window, the depth of the chamber is 1.0...1.2 lengths of the chamber, the depth of the inlet window is equal to the depth of the pneumatic separation channel.

The presence of an expansion chamber with a curved reflective partition with an optimal ratio of design parameters allows the pneumatic system to operate effectively in all modes (preliminary, primary and secondary cleaning) - to capture the separated particles of feed grain from the air flow with low hydraulic resistance.

Figure 1 shows a diagram of the pneumatic system of a universal grain cleaning machine, and Figure 2 shows a diagram of the expansion chamber.

The pneumatic system of the grain cleaning machine contains pneumatic separating channels 1 and 2 for pre-sieve and post-sieve separation with input devices 3 and 4 for the material being cleaned and air exhaust channels 5 and 6, a radial fan 7 with an input opening 8 and an output branch pipe 9, a suction chamber 10, an expansion chamber 11 with a curved reflective partition 12, a cyclone 13, an air duct 14, a loading device 15 for the original material, devices 16, 17, 18 and 19 for removing cleaned, feed grain and waste. In the air exhaust ducts 5 and 6, throttle valves 20 and 21 are installed. The expansion chamber 11 adjoins the pneumatic separating duct 2 of the post-screen separation on the side of its branch 22. The curved reflective partition 12 of radius R _n is located inside the expansion chamber 11, its upper end adjoins the outer wall of the branch 22 of radius R , and the lower one forms with the wall of the chamber an outlet window 23 of depth H _out and is located above the edge of the inlet window 24 at a distance H _n , equal to at least two of its depths H _in . The depth H _out of the outlet window 23 is 0.4 ... 0.5 of the length L _РК of the expansion chamber. The length L _РК of the expansion chamber 11 is 4 ... 5 depths H _{in of} the inlet window 24, its depth H _РК is 1.0 ... 1.2 of the length L _РК of the chamber. The depth H _of the inlet window 24 is equal to the depth h _{of the PSC} of the pneumatic separation channel 2.

The pneumatic system of the grain cleaning machine works as follows.

The initial material is evenly distributed by the loading device 15 across the width of the pneumatic system and, under the action of gravity, falls into the device 3, by means of which it is fed into the pneumatic separating channel 1 of the pre-screen separation. The air flow created by the radial fan 7 blows through the grain material and removes light impurities and dust from it, which are fed through the air exhaust channel 5 into the suction chamber 10. After cleaning in channel 1, the grain material is fed through the outlet device 16 to the screen mill (not shown in the drawing), where large and small impurities that differ from the main crop in width and thickness are separated, and then by device 4 it is directed into the pneumatic separating channel 2 of the post-screen separation for repeated blowing.

During preliminary and primary cleaning, light impurities and dust are lifted by the air flow up the pneumatic separation channel 2, through the inlet window 24 they enter the expansion chamber 11, due to the presence of the curved reflective partition 12 they perform a V-shaped movement and through the outlet window 23 and the air outlet channel 6 they are transported into the suction chamber 10. Randomly separated shrunken, crushed, small grains (feed grain) under the action of gravity and inertia settle to the bottom of the chamber 11 and are removed by device 18 from the pneumatic system into the waste fraction separated on the screen mill.

During secondary cleaning, the air flow velocity in the pneumatic separating channel 2 is set higher than during preliminary and primary cleaning. In addition to light impurities and dust, shrunken, crushed, small grains (feed grain) and accidentally separated full-fledged grains of the main crop are removed from the grain material, which, getting into the expansion chamber 11, are deposited in it. Then, device 18 removes them from the pneumatic system and combines with the feed fraction separated on the sieve mill. Light impurities and dust (waste) are transported through channel 6 into the suction chamber 10.

The air flow with light impurities and dust from the suction chamber 10 enters the inlet opening 8 of the fan 7 and through the outlet pipe 9 along the air duct 14 is fed into the cyclone 13. Light impurities and dust are deposited and discharged to the outside by the device 19, and the exhaust and purified air is removed from the cyclone 13 into the atmosphere.

The finally purified material is removed from the pneumatic system through device 17.

Regulation of the air flow rate in pneumatic separation channels 1 and 2 to create optimal separation conditions in accordance with the operating mode of the pneumatic system is carried out by throttle valves 20 and 21. In this case, no additional adjustment of the design parameters of the expansion chamber is required.

The supply of material to the pneumatic system is regulated by the loading mechanisms of the process line.

Experimental studies conducted on a model of the second pneumatic separating channel with an expansion chamber (Fig. 2) made 0.3 m wide and in natural size in the longitudinal-vertical plane (chamber length L _РК = 0.5 m = 5 H _вх ; chamber depth H _РК = 0.6 m = 1.2 L _РК ; inlet window depth H _вх = h _ПСК = 0.10 m; outlet window depth H _вых = 0.2 m = 0.4 L _РК ; installation height of the lower end of the reflective partition H _п = 0.2 m = 2 H _вх ; depth of the outlet channel 6 h _отв = 0.12 m; reflective partition with a radius of curvature R _п = 0.1 m), it was established that at an air flow rate in the ПСК of 10.0 ± 0.1 m/s, the effect of sedimentation of forage grain amounted to 96.8% (loss of feed grain 3.2% with an acceptable level of 5.0%) with a small hydraulic resistance of the expansion chamber ( P _РК = 200.0 Pa).

Thus, the presence of an expansion chamber with a curved reflective partition with an optimal ratio of design parameters allows the pneumatic system to operate effectively in all modes (preliminary, primary and secondary cleaning) - to capture the separated particles of the feed fraction of grain from the air flow with acceptable losses of feed grain in waste and low hydraulic resistance.

Claims (4)

1. A pneumatic system of a grain cleaning machine comprising pneumatic separating channels for pre-screen and post-screen separation with devices for introducing the material to be cleaned and air exhaust channels equipped with throttle valves, a radial fan whose inlet opening is connected to the air exhaust channels by means of a suction chamber, and whose outlet pipe is connected by means of an air duct with a cyclone, a loading device for the initial material, devices for removing cleaned grain and waste, the pneumatic separating channel for post-screen separation is equipped on the side of its outlet with an expansion chamber with a device for removing feed grain and is connected to it by an inlet window, characterized in that the expansion chamber is equipped with a curved reflective partition, the upper end of which adjoins the outer wall of the outlet of the pneumatic separating channel, and the lower end forms an outlet window with the wall of the chamber with a depth equal to 0.4 ... 0.5 of its length, and is located above the edge of the inlet window on a distance equal to at least two of its depths. 2. The pneumatic system of a grain cleaning machine according to paragraph 1, characterized in that the length of the expansion chamber is 4...5 depths of the input window. 3. The pneumatic system of a grain cleaning machine according to paragraph 1, characterized in that the depth of the expansion chamber is 1.0...1.2 times the length of the chamber. 4. The pneumatic system of a grain cleaning machine according to paragraph 1, characterized in that the depth of the input window is equal to the depth of the pneumatic separating channel.

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