DD265468B5

DD265468B5 - METHOD FOR DETECTING STONES ON BELT BELT FOLDER

Info

Publication number: DD265468B5
Application number: DD30752787A
Authority: DD
Inventors: Heinrich Heinisch; Horst Firle
Original assignee: Ver Mitteldeutsche Braunkohlen
Priority date: 1987-10-02
Filing date: 1987-10-02
Publication date: 1994-01-13
Also published as: DD265468A1

Description

Es zeigt sich, daß das Verfahren grundsätzlich zur Feststellung von Fremdkörpern aller Art eingesetzt werden kann, sofern deren Dichte höher als die des übrigen Fördergutes ist. Das betrifft also ggf. auch relativ große Eisenteile im Fördergutstrom.It turns out that the method can be used in principle for the detection of foreign bodies of all kinds, provided that their density is higher than that of the other material to be conveyed. So this may also affect relatively large pieces of iron in Fördergutstrom.

embodiment

Die Erfindung soll nachstehend an einem Ausführungsbeispiel näher erläutert werden. In den dazugehörenden Zeichnungen zeigen:The invention will be explained in more detail below using an exemplary embodiment. In the accompanying drawings show:

Fig. 1: Die Anordnung der Meßwertaufnehmer zur Ausübung des Verfahrens am Traggerüst des Gurtbandförderers Fig. 2: Eine geeignete AuswerteelektronikFig. 1: The arrangement of the transducers for performing the method on the support frame of the belt conveyor Fig. 2: A suitable evaluation

Fig. 3: Den Signalverlauf bei unterschiedlichen Inhomogenitäten im FördergutstromFig. 3: The waveform at different inhomogeneities in Fördergutstrom

Am Traggerüst 4 des Gurtbandförderers 1 sind die Meßwertaufnehmer 2; 3 für Volumen und Masse angebracht. Als Meßwertaufnehmer 2 für die Ermittlung des Volumens hat sich eine bekannte Fördervolumenmeßeinrichtung auf HF-Basis als geeignet erwiesen, während dio Masse mit Hilfe von an den Tragrollen 5 angebrachten Kraftmeßdosen 3 gemessen wird. In der Auswerteelektronik 6 wird der Quotient aus Masse : Volumen, also das entsprechende Signal für die Darstellung der Dichte ermittelt. Die Auswertelektronik 6 besteht aus dem durch die Meßwertaufnehmer 2; 3 angesteuerten Quotientenbildner 9, dem ein Differentiationsglied 10 nachgeschaltet ist. Dessen Ausgang ist mit einem ersten Eingang eines Vergleichers 11 beschaltet, dessen zweiter Eingang an einer Referenzspannungsquelle 12 sowie einem Regler für die Ansprechschwolle 13 anliegt, wobei der Regler 13 weiter mit dem Ausgang 14 des Vergleichers 11 verbunden ist. Während über die Referenzspannungsquelle 12 der Ansprechpunkt der Schaltung gewählt wird, dient der Regler 13 der Einstellung des Spannungshubes des Ausgangssignals 14.On the support frame 4 of the belt conveyor 1, the transducers 2; 3 attached for volume and mass. As a transducer 2 for determining the volume, a known Fördervolumenmeßeinrichtung HF-based has been found suitable, while the dio mass is measured by means of attached to the support rollers 5 load cells 3. In the transmitter 6, the quotient of mass: volume, ie the corresponding signal for the representation of the density is determined. The evaluation electronics 6 consists of the through the transducers 2; 3 controlled quotient generator 9, which is followed by a Differentiationsglied 10. Its output is connected to a first input of a comparator 11 whose second input is applied to a reference voltage source 12 and a regulator for the Ansprechschwolle 13, wherein the controller 13 is further connected to the output 14 of the comparator 11. While the response point of the circuit is selected via the reference voltage source 12, the regulator 13 serves to set the voltage swing of the output signal 14.

Mit Fig. 3 werden die mit dem erfindungsgemäßen Verfahren erzielbaren Signale und ihre Aussagefähigkeit übor den im Fördergutstrom enthaltenen Fremdkörper dargestellt. Während beim Signalverlauf A bei gleichmäßigem Volumenstrom eine plötzliche Massenzunahme gemessen wird, beim Signalverlauf B hingegen gleichzeitig eine Volumenzunahme von Null auf einen endlichen Wert und in gleicher Weise die Masse von Null auf einen endlichen Wert gemessen wird und damit auf einen Stein im Fördergutstrom bzw. auf einen Stein auf dem leeren Fördergurt zu schließen ist, deutet sich beim Signalverlauf C durch gleichmäßige Volumen- und Massenzunahme im kontinuierlichen Fördergutstrom ein verschütteter Frostklumpen an. Nach Signalverlauf D wächst schlagartig des Volumen und langsamer die Masse an. Es handelt sich um Frostklumpen auf dem leeren Fördergurt. Ein zwischen Klumpen und Schollen verborgener Stein, ist durch den Signalverlauf E gekennzeichnet, läßt wiederum durch seine höhere Dichte einen positiven Meßwert aus der Quotientenbildung erkennen. Ein in der Kohle enthaltener Stein zoigt einen Signalverlauf F entsprechend der Dichte ebenfalls mit einem ausgeprägten Maximum, während nach Signalverlauf G Geschiebemergel ohne Steine einen ausgeglichenen Kurvenverlauf bewirkt. Aus den gewonnenen Signalen läßt sich eindeutig ableiten, daß die Gefahr der Beschädigung des Gurtbandförderers 1 nur bei den Signalverläufen A; B; E und F besteht, der plötzliche Dichteanstieg und damit das gewonnene Signal beispielsweise unmittelbar zur Auslösung einer Notabschaltung oder Einschaltung von Mitteln zur Aushaltung des Steines oder dor Steine verwendet werden kann.With Fig. 3, the achievable with the method according to the invention signals and their informativeness are represented by the foreign body contained in Fördergutstrom. While the waveform A at a uniform flow rate, a sudden increase in mass is measured, the waveform B, however, at the same time a volume increase from zero to a finite value and in the same way the mass is measured from zero to a finite value and thus on a stone in Fördergutstrom or on a stone is to close on the empty conveyor belt, indicates the signal curve C by uniform volume and mass increase in the continuous Fördergutstrom a spilled lumps of frost. After waveform D abruptly increases the volume and slower the mass. These are lumps of frost on the empty conveyor belt. A hidden between lumps and clods stone is characterized by the waveform E, in turn can be recognized by its higher density a positive reading from the quotient. A stone contained in the coal zoigt a signal curve F corresponding to the density also with a pronounced maximum, while according to signal curve G Schiebemergel causes without stones a balanced curve. From the obtained signals can be clearly deduced that the risk of damage to the belt conveyor 1 only in the waveforms A; B, E and F exists, the sudden increase in density and thus the signal obtained, for example, directly to trigger an emergency shutdown or involvement of means for holding the stone or dor stones can be used.

Claims

Method for detecting stones and other foreign objects in the conveyed on belt conveyors, characterized in that at a point of the belt conveyor (1) at the same time determines the meter load and the delivery volume of the conveyed material (7), compared the Meßwertpaare and deviations of Meßwertpaare each other taking into account correlated measured value dynamics obtained a measured value and a signal device and / or device for holding the stones and / or Notabschalteeinrichtung is supplied.

For this

2 pages drawings

Field of application of the invention

The invention relates to a method for detecting stones and other foreign bodies in the conveyed on belt conveyors, which lead to damage or increased wear of the conveyor system. Main field of application Lt the Steinaushaltung on conveyors of lignite opencast mining.

Characteristic of the known state of the art

The problem of the detection of stones and other foreign bodies, which can lead to the damage of conveyors in particular of open pit mining, has long been given special attention. In addition to the location of such foreign objects in the mountains themselves, so even before the promotion, were known for the seismic, gravimetric and radiometric examination method, the detection of foreign bodies on the conveyors themselves is of great importance, since in this area serious damage, especially to the Conveyor belts may arise. The detection of metallic foreign bodies can be regarded as solved since measuring methods are available for this purpose which are based on the change in the magnetic properties in the region of the position of the foreign body in the delivery flow.

However, difficulties still exist in the detection of stones, especially when they are hidden in the flow of conveyed material, that is to say they can not be visually recognized. By DD-PS 227538 a solution has already been known, according to which hidden stones in the near-surface area in opencast mines to be located by detecting the anomalous thermal potential field, caused by density inhomogeneities. However, this measurement method is only suitable for rocks of very large dimensions. Smaller stones, however, which are capable of damaging the belt conveyors - in practice, these are already stones with an edge length of greater than 400mm - which are already contained in Fördergutstrom, have only a little deviating from the rest of Fördergut thermal potential field, which are no longer located can. Also, the detection of stones on the belt conveyor with a Isotopenmeßanlage, as proposed by DD-PS 123703, could find no input in practice, since in the required radiation already Gurtstöße falsify the density standards and thus ongoing faulty locations are the result. For this reason, the visual inspection of the belt conveyor on incoming stones has prevailed to this day. However, it fails if these stones are covered by the other conveyed, which is why attempts have been made to initiate with the help of engaging in the Fördergutstrom mechanical Γ aster emergency shutdowns. Such a location system naturally obstructs the Fördergutstrom, especially caking and frostbite in winter operation, so that even such facilities could not prevail.

Object of the invention

The aim of the invention is to reliably locate stones and other foreign matter in the conveyed on webbing conveyors with simple metrological means and to provide a signal for measures of damage prevention on Gurtbandförderer by the foreign body.

The essence of the invention

The invention has for its object to develop a measuring method which clearly allows to detect inhomogeneities of Fördergutstromes and provides readings available, which allow a conclusion on the type of foreign body in Fördergutstrom.

This object is achieved by a mass and volume determination of Fördergutstromes carried out on a base length of the webbing conveyor of, for example = 1 m at the same time and from the density of Fördergutstromabschnittes is determined. Suitably, the mass determination is done by means of a Einrollengurtwaage, which consists of arranged on the support rollers load cells and a Fördervolumenmeßanlage on HF basis. The density is determined by means of a suitable circuit with the help of the quotient formation from the two measured values obtained. Dia Signnlgewinnung done so by determining deviations of the measured value pairs to each other and taking into account the correlated measured value dynamics. Rapid increases in density are generally indicative of danger, so that the signal of density can be used directly to resolve a signal to the equipment personnel, a forced shutdown of the belt conveyor or means to hold the stones.