Radiant energy – Geological testing or irradiation
Patent
1988-07-25
1990-06-05
Hannaher, Constantine
Radiant energy
Geological testing or irradiation
250265, 250267, 250374, 2503851, G01T 500
Patent
active
049316389
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to devices for automatic steering of coal-winning machines according to seam hypsometry and, more particularly, it relates to a method of monotoring hidden coal-rock interface and to a transducer realizing this method and intended to minitor hidden coal-rock interface by registering the intensity of back scattered gamma-radiation.
The present invention can be emploted to utmost advantage for non-contact monitoring of coal-rock interface for automation of front-loading units, cutter-loaders of any size, units for chamber extraction, and other machines operated for full-seam extraction.
The invention can also be employed in geological exploration of bedrock wherever it occurs: on the surface, in mine workings, or in boreholes.
The invention can be further used for measuring the density of soil, rock, and various construction materials in situations of one-sided accessibility to areas being explored. It can be also embodied in mobile density meters for measuring the desity of rock along geological profiles, sections, and routes.
The invention can be also employed for monitoring the thickness of material in an environment of one-sided access to a medium being investigated, with a variable air gap between the transducer and medium, e.g. a layer of material carried by a running conveyer belt, or else moving rolled strip or sheet.
PRIOR ART
There is known a transducer of a hidden coal-rock interface developed in Great Britain (see D. Hartlet "Automatic steering of cutter-loader in Wallstenton Mine", Mining Engineer, 1971, Vol. 130, No. 124, P. 221) comprising a housing accomodating a gamma-ray source and a detector of back scattered gamma-radiation, spaced from the center of the source. The method of monitoring a hidden coal-rock interface embodied in this known transmitter includes irradiating the medium being monitored from the gamma-ray source, registering backward scattered gamma-radiation by the detector, and determining the hidden coal-rock interface from the intensity of backward scattered gamma-radiation thus detected. To ensure reliable performance of the device, the transmitter is urged against the roof of a mine working by a double-acting jack.
To provide favourable conditions for moving the transmitter along the roof, the transmitter is provided with tail portions at the sides of the source and of the detector. The total length of the transmitter with the tail portion is 120 cm.
The transmitter incorporates a cavity detector which disconnects the automatic control system of the cutter-loader when an air gap occurs between the transmitter and the medium being monitored, as the presence of an air gap results in the transmitter sending false signals causing malfunctioning of the entire cutter-loader control system.
Normal performance of the known transmitter is dependent on its reliable engagement with the rock body being monitored, which necessitates the employment of complicated hold-down and urging devices, as well as the incorporation of a cavity-detecting device. Furthermore, the reliability of this contact-type transmitter is affected by its operation in continuous friction-type engagement which is difficult to maintain with adequate dependability from a moving machine. As it has been already mentioned, should an air gap occur between teh transmitter and the medium being monitored, the credibility of data sent out by the transmitter is impaired.
The transmitter is rather large and cannot be built inot the screw conveyor structure of the cutter-loader to reduce to zero the transport lag. On account of the considerable dimensions of the known transmitter, it is positioned at the seam top behind the screw conveyor, which causes a transport lag between the point of application of the control action (accounting for a varying relief of the seam top) and the point of the monitoring of this action. The transport lag impairs the effectiveness of both monitoring and control.
Attempts to operate the known transmitter for monitoring the bottom of a seam
REFERENCES:
patent: 3019338 (1962-01-01), Monaghan et al.
patent: 3321625 (1967-05-01), Wahl
patent: 3418474 (1968-12-01), Spergel et al.
patent: 3546456 (1970-12-01), Grice
patent: 3846631 (1974-11-01), Kehler
patent: 4525854 (1985-06-01), Molbert et al.
patent: 4701868 (1987-10-01), Regimand
"Regulyator s Izotopnym Datchikom Poroda-Ugol dlya Upravlenia Ochistnymi Kombainami po Gipsometrii Plasta", by Z. A. Chernyak et al., Ugol, No. 12, Dec. 1976 (Nedra, Moscow), pp. 38-39.
"Automatic Steering of Cutter-Loader in Wallstenton Mine", by D. Hartley, Mining Engineer, vol. 130, No. 124, 1971, pp. 221-236.
Chernyak Zinovy A.
Geikhman Isaak L.
Kandala Anatoly I.
Khrapov Valery G.
Nunuparov Georgy M.
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