RU2558737C2 - Method of controlling layer state in aerodynamic systems of machines for post-harvesting treatment of material and device for its implementation - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: invention relates to agricultural machinery industry, particularly to aerodynamic machines for post-harvesting treatment of the material (grain, seeds of herbs, oil crops and others), namely, to the aerodynamic dryers and air systems of seed-cleaning machines. In the method of controlling the layer state in aerodynamic systems of machines for post-harvesting treatment of the material, comprising assessment of the length of the ultrasonic wave path, at that in the information evaluation unit and the servo drive control of louvered shutters the actual length of the ultrasonic wave path with a predetermined value is compared, selected with regard to the characteristics of the material, according to the obtained difference of values the optimal parameters of air feeding into the material treated are determined. To implement the method, on the end walls of the aerodynamic boxes the ultrasonic rangefinders are mounted, transmitting the signal to the information evaluation unit, controlling the servo drive of the louvered shutters located at the entrance to each aerodynamic channel.

EFFECT: increase in efficiency of the method.

2 cl, 4 dwg

Description

The invention relates to agricultural machinery, in particular, to aerodynamic machines for post-harvest processing of material (grain, grass seeds, oilseeds, etc.), namely to aerodynamic dryers and air systems of seed cleaning machines.

Machines for post-harvest grain processing function, as a rule, as part of the production line, therefore the nature of the change in the parameters of the material supplied to the processing (its moisture, clogging, density, etc.) is stochastic, which inevitably causes a stochastic change in all process state variables and significantly affects on their performance, quality and technological reliability of the work process. The control of modes is possible only with the help of dynamic models, which are based on a variable state of the material layer on the working bodies of aerodynamic systems.

The control of the state of the material layer in the aerodynamic systems of machines for post-harvest processing of the material, as a rule, is reduced to maintaining the specific air supply and, accordingly, the gas velocity in the layer. With increased air consumption, the removal of the main material from the layer increases, which leads to an increase in the load on the dust collecting devices, an increase in the loss of the product and energy consumption, and at a lower consumption, to a decrease in the quality of the process (drying, transportation, separation into fractions of the material). In existing designs of dryers and grain cleaning machines, the air supply to the material layer is controlled manually, and the operator controls the optimality of the adjustment.

Recently, in agriculture, ultrasonic sensors and devices have been used to control and automate various processes, and they have also been used in machines for postharvest processing of material, namely, to control the height of the processed material in active ventilation bins.

Ultrasonic flaw detectors operate on the principle of recording reflected ultrasonic signals or receiving attenuated ultrasonic signals.

The closest prototype of the present invention in terms of the method for determining the state of the material layer is a method for detecting a hidden defect using an ultrasonic flaw detector [3]. The defectoscope functioning is based on the property of penetration of ultrasonic waves into solids. The propagation speed of an ultrasonic wave mainly depends on the following parameters of the medium: density of the medium; medium elasticity; the presence of defects (cracks, voids). The sensor has a source and receiver of ultrasonic waves. If we place the object under study between the source and the receiver and measure the time it takes for the waves to travel from the source (point A) to the receiver (point B), knowing the distance AB, we can determine the propagation velocity of the ultrasonic wave when it passes through a specific section of a solid body. This makes it possible to study the internal structure of a solid body for defects and density fluctuations.

The disadvantage of this method in relation to the processed material in post-harvest machines is the impossibility of its use in systems with a stochastic change in the density of the material, for example, grain heap, in the process of processing, because dimensional characteristics and changing “bulk” density are not taken into account.

The technical task of the invention is to increase the reliability, quality of the post-harvest processing of the material and its transportation in the device, reducing energy consumption for post-harvest processing of the material.

The problem is solved in that the proposed method of controlling the state of the layer in the aerodynamic systems of machines for postharvest processing of the material and the device for its implementation due to the distinctive features provides increased reliability, quality of the process of postharvest processing of the material and its transportation in aerodynamic systems and reduced energy consumption for postharvest processing of the material .

The claimed method is illustrated in figures 1-4.

Figure 1 presents a General view of the aerodynamic system of the machine (dryer) for post-harvest processing of material.

Figure 2 shows the control system of the blinds.

Figure 3 presents the shift of the edges of the received signal with respect to the emitted.

Figure 4 shows a diagram for determining the theoretical shortest path traveled by an ultrasonic wave through a layer of material.

At the beginning, the control circuit of the range finder 19 (FIG. 2) generates a distance measurement start signal. Upon receipt of this signal in the ultrasonic rangefinder 6, the generator 13 generates a packet of rectangular pulses with a frequency depending on the geometric dimensions of the material particle 26 (grains), which, using the emitter 14 in the form of an ultrasonic wave, is sent to the space that is received by the receiver 15, which is far from the emitter at a distance L (figures 1, 4). If there is material on the perforated baffle 3, ultrasonic waves pass through the material and fall into the receiver 15, but with a time shift t ₁ (Fig. 3). After that, the receiver 15 transmits the received pulses to the transducer of the received signal 16 (Fig.2), where the determination of the edge shift time t _{1 of the} outgoing 24 and 25 received pulses (Fig.3) takes place. The front shift t _{1 is} proportional to the "path" of the stochastic layer passing by the ultrasonic wave (the course of the ultrasonic wave in the stochastic layer). Based on a comparison of the frontal shift, an impulse is formed with a duration proportional to the indirectly measured distance of the "path" (travel) of the ultrasonic wave. The distance L _З - the theoretical shortest "path" of the ultrasonic wave from the emitter 14 to the receiver 15 through the material layer (Fig. 4) - will depend on the state (degree of fluidization) of the layer, which, subject to the diffraction conditions of ultrasound when interacting with a material particle, is indirectly formula (1):

where L _Z is the theoretical shortest path of an ultrasonic wave through a layer of material, mm;

L is the distance between the emitter and the receiver, mm;

d _e is the equivalent particle diameter of the material, mm;

n is the number of particles of material on the shortest path of the ultrasonic wave;

l _e - equivalent circumference of a particle, mm.

where a, b, c - respectively the length, width and height of the particle, mm

Obviously, L ₃ can take values

where L _Z.P. - the path of an ultrasonic wave passed through a layer of dense material.

In the aerodynamic systems of machines for postharvest processing of the material, the optimal state of the layer (operating mode) corresponds to a well-defined L _{Z. opt.} , which in practice can be calculated taking into account the dependences (1-4) and the optimal porosity of the layer or determined experimentally.

Next, the pulse is transmitted to the comparison circuit 18 of the information evaluation unit 17, which compares the optimal L _{Z. opt.} for the operation of the aerodynamic system on a specific material or the state (fluidization) of the layer with a measured distance L ₃ (the current state of the layer). If it is necessary to adjust the angle of the louver shutter, the comparison circuit 18 transmits a signal to the control circuit of the servo drive 20, which, in turn, changes the angle of the position of the servos 21 according to the established program. If the perforated partition 3 is not occupied by the material (L = L _З ), then the louver shutters 11 will turn to the “louver shutters are closed” position 12. Depending on the state of the material and program settings in the mode circuit 23, the central control processor 22 sets the evaluation unit operation mode information 17.

T.O. in the presence of material on the partition, the path L _З traveled by the ultrasonic wave will always be greater than L - the distance between the emitter and the receiver. When the state of the layer (its fluidization) changes, the number of particles in the path of the ultrasonic wave and L ₃ will change; according to this indicator, it is proposed to monitor and control the level of the fluidization of the layer.

Depending on the humidity, type and other parameters of the material, the program generates a control signal for the servo drive of the louver shutters 11, which ensures the maintenance of optimal parameters of the air supply to the processed material.

Known aerodynamic installation for drying bulk materials containing a shaft, in which there are drying boxes with perforated partitions. A drying bin is installed above the shaft, and a drying bin with a dispenser is fixed under the shaft. On the side walls of the mine are fixed air distribution ducts with movable dampers that distribute air flows into the ducts [1].

The disadvantage of this installation is that each distribution flap regulates the air flow in two drying boxes, which makes it difficult to control the state of the layer, and also in the absence of dried seed on one of the boxes leads to a decrease in the transporting capacity of the other drying box (as the air goes along the path of least resistance), loss of drying agent to the atmosphere and a decrease in the economic efficiency of drying.

The closest prototype of the invention in terms of the device is a production plant [2], including fans and connected air distributors with drying boxes. A drying bin is installed above the upper drying box, and the lower one is equipped with an outlet device. In the air distributors there are channels with rotary shields designed to adjust the distribution of air through the channels. The drying boxes are made of air supply and conveying channels, between which perforated sieves are rigidly installed. The first, third and fifth drying boxes are connected to one frame, the second, fourth and sixth are connected to another frame.

The disadvantage of the devices [1, 2] is the lack of an automatic control system for the position of the air dampers, the operator must manually control the amount of air supplied, while it is not possible to maintain optimal air flow in the drying chambers depending on their load.

The technical task of the invention is to create a device for implementing the method of controlling the state of the material layer in the aerodynamic systems of machines for postharvest processing of the material, maintaining optimal parameters of the air supply to the processed material and reducing energy consumption for postharvest processing of the material.

The problem is solved in that the proposed device due to the distinguishing features will ensure the maintenance of optimal parameters of the air supply to the processed material and reduce energy consumption for post-harvest processing of the material.

The essence of the claimed device is illustrated in figures 1, 4.

The aerodynamic system of a machine (for example, a dryer) for post-harvest processing of the material (Fig. 1) contains a shaft 1 in which aerodynamic ducts 2 with perforated partitions 3 are installed. An active overflow threshold is fixed at the end of each perforated partition 4. On the sides of the shaft 1 are fixed air distribution boxes 7 with louvred shutters 11 controlled by servos (Heat generator, cavity cavities and cyclones for cleaning exhaust air are not conventionally shown). A drying bin 5 is installed above the shaft 1, and a drying bin 8 with a dispenser 9 is fixed under the shaft 1.

The aerodynamic system of the machine (dryer) for post-harvest processing of the material works as follows. Material with its own weight from the drying hopper 5 enters the perforated baffle 3 of the aerodynamic box 2, where it is exposed to jets of air coming out at an acute angle from the slots of the perforated baffle 3. Distribution of the air flow through the aerodynamic boxes 2 is carried out using a distributor 10, and its consumption installed by louvre shutters 11. During operation of the machine for post-harvest processing of the material for the presence and condition of the material on the perforated partitions 3 aerodynamically Of these boxes 2 are monitored by ultrasonic rangefinders 6, consisting of an emitter 14 and an ultrasonic wave receiver 15, mounted on the end walls of the aerodynamic boxes (Fig. 4) and transmitting a signal to the information evaluation unit that controls the servo drive of the louvered shutters located at the entrance to each aerodynamic channel.

In the process of moving the material through the aerodynamic ducts, the moisture is gradually removed and the material layer is divided into fractions that differ in aerodynamic properties and dimensional characteristics. In this case, the small heavy fraction moves along the surface of the perforated gratings 3, the bulk of the material occupies a middle position in the layer, and the light soars into the upper layer and is carried out into the cyclones with exhaust air. Podsory small heavy impurities through the gap of the active overflow threshold 4 are returned again to the space between the aerodynamic ducts. The material is cooled in a cooling column.

References

1. Pat. 2275566 Russian Federation, IPC F26B 17/16. Aerodynamic installation for drying bulk materials / Zimin E.M., Volkhonov M.S .; applicant and patent holder FGOU VPO Kostroma State Agricultural Academy, publ. 10/10/2005, bull. No. 12. - 4 s .; silt.

2. Pat. 2135916 Russian Federation, IPC6 F26B 17/16. Aerodynamic installation for drying bulk materials / E.M. Zimin, M.S. Volkhonov, S.I. Sidorov, S.S. Volkhonov, G.S. Berezovsky; applicant and patent holder FGOU VPO Kostroma State Agricultural Academy, publ. 08/27/99, bull. Number 24. - 5 s .; silt.

3. DeviceSearch.ru [Electronic resource], which provides information on measuring instruments. Access mode: http://www.devicesearch.ru. Date of treatment 05.11.2013

Claims (2)

1. The method of controlling the state of the layer in the aerodynamic systems of machines for post-harvest processing of material, comprising estimating the path length of the ultrasonic wave, characterized in that in the unit for evaluating information and controlling the servo drive of the blinds according to the invention, the actual path length of the ultrasonic wave is compared with a predetermined value selected from taking into account the characteristics of the material, the resulting difference in values determines the optimal parameters of the air supply to the processed material. 2. A device for implementing the method of controlling the state of the layer in the aerodynamic systems of machines for postharvest processing of material, consisting of a shaft, aerodynamic ducts, characterized in that ultrasonic rangefinders are installed on the end walls of the aerodynamic ducts, transmitting a signal to the information evaluation unit, which controls the servo drive of the louver shutters located at the entrance to each aerodynamic channel.

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