RU2502978C2 - Method to determine density of roll from stems of bast crops and device for its realisation - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: force of resistance to insertion of a feeler into a roll is measured in the plane of its diametral cross section in direction from periphery to core and speed of feeler motion, the produced results are compared with reference values, and based on the results of comparison they determine the density of the roll. At the same time the device is equipped with a channel for measurement of motion speed of the feeler, comprising the serially connected speed sensor, amplifier and converter of frequency into voltage. Besides, the output of the amplifier in the channel of measurement of force of resistance to feeler insertion and the outlet of the converter of frequency into voltage are connected to an indicator via a voltage divider. As a result of inspection it was established that the relative error of the proposed method for determination of density does not exceed 4.5%, which is less than the error of density measurement by the opposed method almost by 2%.

EFFECT: higher accuracy of measurements.

2 cl, 3 dwg

Description

The invention relates to the field of determining the density of materials and can be used in agriculture and at flax mills for the primary processing of flax raw materials to determine the parameters of rolls formed from stalks of bast crops.

A known method for determining body density by dividing the numerical values of body weight by its volume. However, this method is inefficient and laborious with a large mass of bodies (200-400 kg). In addition, in this way it is not possible to determine the density distribution over the volume of an inhomogeneous body.

There is a way to determine the density of bodies by the speed of propagation of sound waves passing through a substance and comparing the measurement results with reference values (1). In this way, it is also possible to determine only the average density of the material (substance) of the body and it is not possible to measure local density (density at a particular point in the body by its volume) in bodies with different concentrations of material by volume, for example, in rolls from the core to the periphery. This drawback does not allow using this method to configure the baler press system (e.g. PRP-1,6) (2) to form coils from the stems of linen trusts of high humidity with a uniform density distribution in the direction from the core to the periphery, intended for artificial drying linen trusts in rolls in drying plants with a coolant supply from the butt surface of the roll (3). Similarly, using this method, it is not possible to configure the pressing system of a round baler for flax straw in rolls intended for industrial preparation (in washing tanks) of flax strands in rolls, when the core of the roll should be less dense compared to the periphery. The last point is important for the uniformity of the straw soaking.

The prototype of the claimed technical solution is a method for determining the density of a material in a roll in the plane of its diametrical section in the direction from the periphery to the core, by the strength of resistance to penetration of the probe into the roll in this plane, by comparing the measurement results with reference values and by the results of comparison with the determination of density (4). A device for implementing the method comprises a series-connected resistance sensor, amplifier and indicator.

The disadvantage of this method is the low accuracy of measuring the density of the roll, which is due to the significant dependence of the measurement results on the speed of the probe. The speed of the probe changes due to the elastic deformation of the drive links, skidding of the electric motor that occur when there is a sharp change in the density of the material in the roll due to the heterogeneity of the selected tape stems (thick, thin, skipped tape, etc.), changes in the friction forces of the probe tip on the stems along due to changes in the moisture of the stems in the layers of the roll (the top of the selected tape is less wet than the bottom, or vice versa).

The invention is aimed at eliminating the above-mentioned disadvantages of the known, and from its use the following technical result can be obtained: improving the accuracy of measurements. The specified technical result is achieved due to the fact that they measure the force of resistance to penetration of the probe into the roll in the plane of its diametrical section in the direction from the periphery to the core and the speed of the probe, compare the results with reference values and determine the density of the coil from the results of the comparison, the device is equipped with a channel for measuring the speed of the probe containing a speed sensor, an amplifier and a frequency to voltage converter connected in series, the output of the channel amplifier measuring Measuring the resistance to penetration of the probe and the output of the frequency converter into voltage are connected to the indicator through a voltage divider.

The figure 1 shows a device for determining the density of the roll and the structural diagram of the device explaining the essence of the invention, figure 2 is an example of a specific implementation of the object of the invention.

Providing the device with a channel for measuring the speed of the probe and the voltage divider slightly complicates the design in comparison with the prototype, at the same time, it improves the accuracy of density measurements.

The device for implementing the method (figure 1) consists of a tip 1 with a force sensor 2, mounted in a tubular rail 3, driven by guides 4 and 5 by a gear wheel 6 connected to a drive, which is not shown to simplify the figure. The device can be stationary and mobile.

The channel for measuring the resistance to penetration of the probe into the roll is formed by a force sensor (for example, piezoelectric) 2 connected in series, an amplifier 7, a voltage divider 8 and an indicator 9. The channel for measuring the probe speed is formed by a series of inductive frequency sensors 10 mounted by a sensitive surface to the teeth rails in the plane of rotation of the gear wheel 6, an amplifier 11 and a frequency to voltage converter 12, the output of which is connected to a voltage divider 8.

The device operates as follows. When the gear 6 is rotated, the tubular rack 3 moves along the guides 4 and 5. The rotation of the tubular 3 in the guides 4 is eliminated due to the corresponding shapes of the guides and the cross-section of the rack (for example, the square profile of the rail and the square hole in the guides). The deflection of the rack 3 and the exit of the wheel 6 from engagement with the teeth of the rack prevents the guide element 5, which is a stop and is located opposite the gear wheel on the opposite side of the rack 3. The tip 1 with a force sensor 2 is introduced into the roll 13 along a line passing through the axis of the roll in position the roll shown in figure 1. The stop 14 is an obstacle to rolling or shifting the roll.

The signal from the force sensor 2 is amplified by the amplifier 7 and fed to the input of the voltage divider 8. When the inductive frequency sensor 10 interacts with the teeth of the rack 3, signals are generated that are amplified by the amplifier 11 and fed to the input of the frequency converter to voltage 12. From the output of the converter 12, the signal in the form voltage is supplied to the second input of the voltage divider 8. The amplification of the signals is made so that the signal of the channel for measuring the resistance to penetration of the probe is always greater than the signal of the channel for measuring the speed of the probe. In the voltage divider 8 there is a division of voltage signals. The measured value of the division results is indicated by indicator 9.

Figure 2a shows a copy of the waveforms of the change in the force F (in volts) of the resistance to penetration of the probe into the roll along its diametrical section D) (in meters) in the direction from the periphery to the core at different probe speeds: 1-0.5 m / s; 2-1.0 m / s; 3-1.5 m / s.

Figure 2c shows copies of the oscillograms of a change in the relative value — the ratio of the resistance to penetration of the probe into the roll along its section D in the direction from the periphery to the core to the value of the speed of the probe at the same different speeds of the probe.

From the above dependencies, the difference in density indicators is obvious, confirming the predominant difference of the claimed subject matter.

When comparing the claimed and opposed method, the actual density distribution in a roll of stems of linen trusts was determined in layers as the roll was unwound. The layers in the roll were separated by twine laid in the roll together with the flax trust in the process of pressing the roll. When unwinding the roll, the circumference of the roll was measured after removing each layer of stems. A portion of the stalk layer 200 mm long was cut from the stalk layer symmetrically to the probe line. The weight of the cut stems was determined by weighing, and the cut volume of the stems from each layer of the roll was calculated from the calculated diameters and the known height of the cut section of the layer. Density was determined as the quotient of the division of mass by volume. As a result of the audit, it was found that the relative error of the proposed method for determining the density does not exceed 4.5%, which is less than the error in measuring the density by the opposed method by almost 2%.

Information sources

1. Glybkin I.P. Automatic densitometers. K., 1965, p. 612

2. Kolesnikov Yu.A., Sapunkov A.P. The manual of the baler, - M .: Agropromizdat, 1985, 127 p.

3. Lyubarsky V., Jonushass 3., Mikyalenis S. Installation for drying raw materials "Flax and hemp", 1987, No. 5, p. 37.

4. Osobov V.I., Vasiliev G.K., Haymaking machines and complexes. - M. Mechanical Engineering, 1983, p. 284.

Claims (2)

1. The method of determining the density of a roll of stalks of bast crops, which consists in measuring the resistance to penetration of the probe into the roll in the plane of its diametrical section in the direction from the periphery to the core, characterized in that they measure the resistance to penetration of the probe into the roll in the plane of its diametrical section in the direction from the periphery to the core and the speed of the probe, compare the results with reference values and determine the density of the roll from the results of the comparison. 2. The device for implementing the method according to claim 1, having a measuring channel containing a series-connected force sensor, an amplifier and an indicator, characterized in that it is equipped with a channel for measuring the speed of the probe, containing a series-connected speed sensor, an amplifier and a frequency to voltage converter moreover, the output of the amplifier channel for measuring the resistance to introducing the probe into a roll and the output of the frequency to voltage converter are connected to the indicator through a voltage divider.

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