SU1656121A1 - Sensor of hidden coal-rock interface - Google Patents

Abstract

The invention is intended for automatic driving of coal mining machines on formation hypsometry. The purpose of the invention is to expand the required range of insensitivity to fluctuations in m-air gap on coal-mining machines of various types, preserving the minimum dimensions of the sensor. For the third detector, the detector is installed above the filter window at a distance that is not shorter than the 6ye.tOio (-three urban gap. Raistop V, between the measurement source and the center of the detector is greater than or equal to the thickness of the sensor body material between the source - and the detector, but does not exceed the required maximum air gap. In window 4 between filter-coal and detector 3 there is a filter 5. Its width is equal to the width of window 4. Between the opposite; 4 along the line of source: Image and slit filter: near to source 2, slit 6, area Si, and farthest from source 2, slit 7, area S2. Detector 3 detects gamma radiation emitted by source 2, the intensity of which is a measure of the thickness of the coal bundle. 6 and 7 are given by the transverse dimensions of the window 4 under the detector, and their areas can be changed by changing the width of the slits. 7 Il and iL.

Description

The invention relates to devices for the automatic driving of coal mining machines on formation hypsometry.

The purpose of the invention is to expand the required range of insensitivity to air gap fluctuations on coal-mining machines of various types while maintaining the minimum dimensions of the sensor.

FIG. 1 shows the sensor, a general view and a section of a pack of coal and rocks under it; in fig. 2 section A -A in FIG. 1; in fig. 3 - experimental dependences, explaining the principle of compensation for the effect of the air gap in the gun, designed to be mounted on the auger of the combine; in fig. 4 - the same, in the sensor intended for installation in the lining section of the unit; in fig. 5 shows experimental dependences of the change in the output signal of the sensor in the absence of a filter; in fig. 6 shows the output characteristics of the sensor for the units; in fig. 7 - the same; for combines.

The sensor consists of a steel housing 1, a gamma-radiation source 2, a detector 3, a window 4 under the detector 3, a filter 5, which

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irpmo.lo ::: ::; and windows 4 between controlled rK i-.4 ..; ; i wasp coal carbon and detector 3. Filter 5 has a width equal to the window-l under the detector. Between the proc chololozhim sides of the window ps line; - t ::;:;: and:.: Imlu- sion - the detector and filter ...:.:;: -;; : s gap; close to the source, and -in Si, and far from the source, 7 gb. S2.

The datj is mounted in the node 8 of the mountain Ashgany in such a way that the distance from the working surface of the advanced sensor

1 KOiL1; 1P; STZ is reduced by NOMKI LNORL

 Yulduts-N,). :; y;:.: or oz Pos 9, the magnitude of which yb-bearing and depending on the object of the auto-m. g AC-IK (combine, unit). When ustakoz-;, e az-i x, for example, in the sections of support s.grogyT: -. u.-j mask fins select prs cel 5-15: v:.; w; exclude the influence of either the pin and,; - pg M ugznitske mz screw auger in: I -,;:., T ,, T;,: / :. ; i ,; These limits must be

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iox.Mt-U i iec:: -: .-: sensor damage in the pro (;; - About coal,

  pacc i OfiHna I 10 between the children: ::: ;;;; 1g: -; ohm g - sbfaetsa depending on;: kz e -:: rr; t is equal to 5 mi &date:; And :: r4.; R:; - :; aanz-chey for aggregates, and 15, dam: ;; a:; tch: lk is intended for lightning,

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i c in l u.ch; v; l with s and o there nst m and s- and m and ln about yjv; e; - ;: f .iv-. S gd gba and use it Ses redistribution:; n body: -; zk for automation; and} -o:; yg: o, so, automation center units.

Hirks-iv fi: iu the possible distance between the source and the radiation and the detector, depending on the size of the sensor, depends. Only one thickness of the material from the fis-case of the sensor between the source and the detector is necessary to absorb the direct radiation of the source. In pe ™: .r; S.-r -; - .S: o; -;.; Truktspi sensor with active usptg ion: chg; yhz gsimz-radiation of 220 mCi rsdione-: lnd of the crimps 241, energy 60; .Sv} then; the main unit, -.- t, -. material (steel) of the body of the dzt- -; ika -; 0 ;; g; -l / radiation source and pH detector; h; .- ;. РЗ;,

 i jj iii. The filter "l" is chosen as such. chtbb; (Bleed by the filter of the sample. t.j scattered gamma radiation

lay within 10 K 20. Then from the formula (s / es1) the material and the required thickness of the filter are determined.

The intensity of the radiation arriving at the detector through slit 6 is marked with an increase in the air gap in the hBsi Bz2 range (Fig. 3 and 4, curve 1, and the intensity of radiation through slit 7 increases, curve 2). If the area of the slots is chosen from the condition

with S3; -S.l „

0 - si:, then total, registered5

0

The intensity measured by the detector (curve 3) does not depend on the air gap in the heal-Paz2 range.

It can be seen that curve 1 has an inversion nature. Inversion is explained by the fact that, at small air gaps, the intensity of the radiation detected by the detector increases due to an increase in the mutual visibility zone of the source-detector in the scattering medium coal-rock to a value. and then falls by increasing the distance between the detector and the radiation scattering medium.

The position of the inversion point on curve 1 relative to the abscissa axis hB3 determines the lower limit IH3 of the required insensitivity range to the air gap oscillations, since the total to the left of the inversion point recorded by the detector, the intensity (curve 3) drops sharply and the sensor becomes sensitive to the air gap oscillations .

In this sensor (without changing its dimensions) the position of the inversion point is selected by changing the distance I 10 between the detector and the window with the filter.

From the experimental dependencies shown in FIG. 5, it can be seen that when the value is 5 mm, the inversion point falls on them. and for mm, per mm, which corresponds to the required values of the lower limit of the insensitivity range:. oscillations of the air gap for installed on the unit and

Having established the distance i 10 between the detector v with a window equal to 5 or 15 mm, depending on the type of sensor, proceed to the choice of the thickness to h; filter and square near the far cracks. Since the lengths of the near 6 and 7 deep slots are given by the transverse gauge / iM window A under the detector, their areas can be changed by changing the width of the slots.

The method of choosing the filter thickness, near and far slits is as follows.

Let it be necessary to ensure that the sensor is insensitive to fluctuations in the air gap in the range from hB3i to hBs2.

Claims (4)

1. The sensor is set up on a model simulating a two-layer coal-rock environment and consisting of graphite plits of variable thickness with a density of p 1.6 g / cm 3 and a concrete block with a density of 2.2 g / cm. The thickness of the graphite plate above the rock is set equal to half the measuring range of the thickness of the coal bundle by the corresponding rock-coal sensor. When using america-241 with an energy of 60 keV as the radiation source, the thickness of the graphite plate above the rock is set to a different 20 mm. 2. Sensor rock - coal is placed above a two-layer medium with an air gap hB3i. The window under the detector is closed with a steel filter of variable thickness, ensuring the presence of only the farthest gap from the source. The dependences of the counting rate of the detector on the size of the air gap ng f (hB3) are removed at different filter thicknesses and the width of the farther gap. By increasing the thickness of the filter, we achieve that the inversion point on the ng 1 (bVz) dependence falls on the value of the air gap size not less than bB3. When using a source from americium-241, the thickness of the steel filter varies from 1 to 7 mm. For sensors mounted on the machine and combine, the size of the groove 2 is 60 and 120 mm, respectively. In this case, the experimentally selected thickness of the steel filter is 2.5 and 5 mm, respectively. 2.1. By installing a filter of a selected thickness under the detector, the dependences of the counting rate on the air gap size (hB3) at different widths of the furthest gap are removed, which is increased until the inversion point on the ng Jvz dependence shifts to hB3 ЬВ32. It is practically sufficient to have seven dependences of the form (hB3) when changing the width of the far slit from 2 to 14 mm, taken every 2 mm. 3. Selecting the thickness of the steel filter according to claim 2 and having obtained a series of dependencies according to claim 2.1, go to the choice of the width of the near slot. 3.1. Sensor rock - coal is placed over a two-layer medium coal - rock with an air gap pvz1. The window under the detector is closed with a steel filter, ensuring that there is only a gap of a certain width closest to the source. In addition, under the steel filter set next to it, a 10 mm thick lead plate, in which there is also only a source closest to the gap, of the same width as in the steel filter. Take off dependence of the counting rate of the detector oi of the air gap size.) at different widths of the near field, the dependence of PB (PVZ) has an inversion character (curve 1 in Figs. 3 and 4). Width near the slots increase as long as the falling nature of the (hB3) s arrays takes place; the range of variation of the air gap from ps1 to bs2. Almost enough to have seven dependencies (hBs) when changing the width of the near click or 1 to 7 mm, taken every 1 mm. 3.2. The window under the detector is completely covered with a steel filter. Under steel filter set lead plate according to claim. 3.1. The dependences of the counting rate of the detector on the size of the air gap pb + f-f (groove) are taken at different widths of the gap closest to the source in lead, the width of which is set each time the same as in clause 3.1. As a result, seven dependences of the form (Lb3) are obtained when the width of the near width of the proximal gap in lead varies from 1 to 7 mm removed every 1 mm. 3.3. Using dependencies in accordance with clauses 3.1 and 3.2, subtracting their ordinates, build seven dependencies of the form ne - pb + f f (has). 4. From the series of increasing dependencies in accordance with clause 2.1 and the series of decreasing dependencies in accordance with clause 3.3, two such ones are selected, when adding the ordinates of which receive the dependence rig + (PB-Pb + f) -const when the air gap changes from hB3i to pVE2 (curve 3 in fig. 3 and 4). The width of the proximal and distant slots is unambiguously determined by the selected dependences, since each dependency of the series is obtained at a certain value of the width of the proximal or distant slit. Based on this, a latent coal-rock monitoring sensor with a size of 112x62x65 mm, a radiation source of americium 241 with a capacity of 220 mCi and a radiation detector of seven small-sized, parallel-installed SBM-21 counters have been developed. For the sensor installed in the lining section of the unit, the parameters are as follows: thickness of the steel filter 2.5 mm; the width and area of the proximal gap, respectively, 3 mm and 156 mm2; the width and area of the far gap, respectively, 62 mm and 322.4 mm; The distance between the detector and the window is 5 mm. For the sensor mounted on the auger of the combine, the parameters are as follows: the thickness of the steel filter is 5 mm; the width and area of the proximal gap, respectively, 4.3 mm and fj 223.6 mm; the width and area of the far gap, respectively, 10 mm and 520 mm; the distance between the detector and the window is 15 mm. The output characteristics of the sensor installed in the lining section of the unit are shown in Fig. 6, and the sensor installed on the auger of the combine is shown in Fig. 7. The numbers in the crises indicate in millimeters the thickness of the coal pack above the rock. It can be seen that the counting rate n is practically constant within n ± o, where cr - vf when the air gap changes from B B3 to MF 2 To eliminate stitching of the detector through the filter gaps for example, epoxy compound. This compact coal-rock control sensor is versatile and can be used to automate frontal units, combines of any size, units for chamber excavation, etc., operating with a recess at full capacity. Claims of the sensor for monitoring the latent boundary coal rock according to ed.St. No. 684952, about tl and h and y - y and so that, in order to expand the required range of insensitivity to fluctuations in the air gap on coal-mining machines of various types with maintaining the minimum dimensions of the sensor, the detector is installed above the window with the filter at a distance that does not exceed the required minimum air gap, and the distance between the radiation source and the center of the detector is greater than or equal to the thickness of the sensor body material between the source and the detector, but does not exceed the required value maximum air gap. 7 Sh 4 (rig. G phage. one Sh WQ 200 1501 1001 501 U 20 30 40 50 60. hQftff 90 100 110 software 0zg woa 15001QO & VF 10 20 Jtf 40 Eid 60 FIG. five 25 200H  I 1001 50 40 83i 20 -50 W 50 6 $ fyfyiMH i fig d Of WITH 83 N ъ "Q fv WITH ; NW, „, 4-q i N "Li cs "V, four "five