CHAIN FAULT DIAGNOSIS SYSTEM AND METHOD FOR SCRAPER CONVEYOR

Abstract

A chain fault diagnosis system and a chain fault diagnosis method for a scraper conveyor are provided. The diagnosis system includes a strain rosette attached on a top end surface of each sprocket tooth of the scraper conveyor. The strain rosette is connected to a signal gathering unit fixed on a scraper conveyor roller through a shielded conductor, the signal gathering unit sends a gathered signal to a wireless receiving device by means of wireless transmission, and the wireless receiving device transmits the gathered signal obtained thereby to an industrial control computer through a USB interface. The diagnosis method includes the following three steps: chain dislocation/skip fault judgment, chain breakage fault judgment and chain seizure fault judgment. A comprehensive monitoring of the chain state of the scraper conveyor is performed by measuring strain magnitudes in different directions of the sprocket tooth in real-time, transmitting the gathered signal to the industrial control computer via a wireless transmission method and dynamically diagnosing the faults of seizure, dislocation, skip and breakage of the scraper conveyor chain based on the obtained strain data.

Claims

1. A chain fault diagnosis system for a scraper conveyor, comprising a scraper conveyor roller and two sprockets, which are, as double-row gears, arranged at intervals on the scraper conveyor roller, and on each of which a chain is installed, the chain fault diagnosis system comprising: a strain rosette attached on a top end surface of each sprocket tooth of the scraper conveyor, wherein the strain rosette is connected with a signal gathering unit fixed on the scraper conveyor roller through a shielded conductor, a wireless transmission module of the signal gathering unit sends a gathered signal to a wireless receiving device by means of a wireless transmission, and the wireless receiving device transmits the gathered signal obtained to an industrial control computer through a USB interface, wherein the strain rosette comprises a 90? strain gauge arranged in parallel with a central axis of the sprockets and a 0? strain gauge arranged vertically to the 90? strain gauge.

2. A chain fault diagnosis system for a scraper conveyor according to claim 1, wherein the signal gathering unit comprises a power module which is connected to a signal conditioning circuit, an MCU micro-control chip and a wireless transmission module, respectively, wherein the MCU micro-control chip is connected to the signal conditioning circuit, a storage module and the wireless transmission module, respectively.

3. A chain fault diagnosis system for a scraper conveyor according to claim 1, wherein both the 0? strain gauge and the 90? strain gauge are resistance strain gauges with temperature compensation.

4. A chain fault diagnosis method for a scraper conveyor based on the chain fault diagnosis system as claimed in claim 1, comprising three steps: a chain dislocation/skip fault judgment, a chain breakage fault judgment and a chain seizure fault judgment, wherein the chain dislocation/skip fault judgment comprises: calculating a difference ?f.sub.90=f.sub.90.sup.1?f.sub.90.sup.2 between measurement results of the 90? strain gauges on the top end surfaces of two sprocket teeth at a same position on one sprocket, wherein if |?f.sub.90|?J.sub.1 and this is true for a number of consecutive sprocket teeth, then determining that a scraper is inclined, and when the scraper is inclined, further calculating a difference ?f.sub.0=f.sub.0.sup.1?f.sub.0.sup.2 between measurement results of the 0? strain gauges on the top end surfaces of two sprocket teeth at a same position on the two sprockets on the same axis of the roller; if |?f.sub.0|?J.sub.2, then determining that a chain dislocation/skip fault occurs, wherein J.sub.1=0.1?(f.sub.90.sup.1+f.sub.90.sup.2) and J.sub.2=0.1?(f.sub.0.sup.1+f.sub.0.sup.2); the chain breakage fault judgment comprises: calculating a difference ?f.sub.0=f.sub.0.sup.1?f.sub.0.sup.2 between the measurement results of the 0? strain gauges on the top end surfaces of the two sprocket teeth at the same position on the two sprockets on the same axis of the roller, wherein if |?f.sub.0| increases suddenly and exceeds a set threshold J.sub.3 and this is true for a number of consecutive sprocket teeth, then determining that a chain breakage fault occurs, wherein the set threshold J.sub.3 is 0.2?(f.sub.0.sup.1+f.sub.0.sup.2; and the chain seizure fault judgment comprises: when the measurement results of the 0? strain gauges on the top end surfaces of the two sprocket teeth at the same position on the two sprockets both increase suddenly and exceed a set threshold J.sub.4, if the measurement results of the 0? strain gauges have no periodical and alternating changes, then determining that a chain seizure fault occurs, wherein the set threshold J.sub.4 is 1.5 times of the measurement result of the corresponding 0? strain gauge in normal condition.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 shows the structural diagram of the system of the invention; and

[0015] FIG. 2 shows the structural schematic diagram of the signal gathering unit of the invention.

[0016] In the figures, 1 refers to the strain rosette, 2 refers to the shielded conductor, 3 refers to the signal gathering unit, 4 refers to the wireless receiving device, and 5 refers to the industrial control computer.

DESCRIPTION OF THE EMBODIMENTS

[0017] The invention will be further explained in combination with the attached drawings.

[0018] As shown in FIGS. 1 and 2, in the chain fault diagnosis system for the scraper conveyor of the invention, the scraper conveyor includes a scraper conveyor roller and two sprockets, which are, as double-row gears, arranged at intervals on the scraper conveyor roller, and on each of which a chain is installed; the diagnosis system includes a strain rosette 1 attached on the top end surface of each sprocket tooth of the scraper conveyor, wherein the strain rosette 1 is connected with a signal gathering unit 3 fixed on the roller of the scraper conveyor through a shielded conductor 2, the wireless transmission module of the signal gathering unit 3 sends a gathered signal to a wireless receiving device 4 by means of wireless transmission, and the wireless receiving device 4 transmits the gathered signal obtained to an industrial control computer 5 through a USB interface.

[0019] The strain rosette includes a 90? strain gauge arranged in parallel with the central axis of the sprockets and a 0? strain gauge arranged vertically to the 90? strain gauge. Both the 0? strain gauge and the 90? strain gauge are resistance strain gauges with temperature compensation. The 0? strain gauge measures the deformation of the sprocket tooth in the chain movement direction; the 90? strain gauge measures the deformation of the sprocket tooth in the direction vertical to the chain movement direction.

[0020] The signal gathering unit 3 includes a power module which is connected to a signal conditioning circuit, an MCU micro-control chip and a wireless transmission module respectively, wherein the MCU micro-control chip is connected to the signal conditioning circuit, a storage module and the wireless transmission module respectively.

[0021] The chain fault diagnosis method for a scraper conveyor based on the above diagnosis system includes three steps: chain dislocation/skip fault judgment, chain breakage fault judgment and chain seizure fault judgment:

[0022] Chain dislocation/skip fault judgment: during normal operation, the tension of the two scraper conveyor chains are basically the same, and the deformation of the top end surfaces of two sprocket teeth at the same position on the same sprocket in the direction vertical to the chains is the same; the difference ?f.sub.90=f.sub.90.sup.1?f.sub.90.sup.2 between the measurement results of the 90? strain gauges on the top end surfaces of two sprocket teeth at the same position on one sprocket is calculated; if |?f.sub.90|?J.sub.1 and this is true for a number of consecutive sprocket teeth, then it is judged that a scraper is inclined; when the scraper is inclined, the difference ?f.sub.0=f.sub.0.sup.1?f.sub.0.sup.2 between the measurement results of the 0? strain gauges on the top end surfaces of two sprocket teeth at the same position on the two sprockets on the same axis of the roller is further calculated; if |?f.sub.0|?J.sub.2, then it is judged that chain dislocation/skip fault occurs; J.sub.1=0.1?(f.sub.90.sup.1+f.sub.90.sup.2) and J.sub.2=0.1?(f.sub.0.sup.1+f.sub.0.sup.2).

[0023] Chain breakage fault judgment: in case of chain breakage fault, the tooth deformation of the sprocket having broken chain decreases suddenly, and the tooth deformation of the sprocket having no broken chain suddenly increases; the difference ?f.sub.0=f.sub.0.sup.1?f.sub.0.sup.2 between the measurement results of the 0? strain gauges on the top end surfaces of the sprocket teeth at the same position on the two sprockets on the same axis of the roller is calculated; if |?f.sub.0| increases suddenly and exceeds the set threshold J.sub.3 and this is true for a number of consecutive sprocket teeth, then it is judged that chain breakage fault occurs; the threshold J.sub.3 can be 0.2?(f.sub.0.sup.1+f.sub.0.sup.2).

[0024] Chain seizure fault judgment: in case of chain seizure fault, the tension of the two chains suddenly increases at the same time, and periodical and alternating change does not occur subsequently; when the measurement results of the 0? strain gauges on the top end surfaces of the two sprocket teeth at the same position on the two sprockets both increase suddenly and exceed the set threshold J.sub.4, if the measurement results of the 0? strain gauges have no periodical and alternating changes, it is judged that chain seizure fault occurs; the J.sub.4 is 1.5 times of the measurement result of the corresponding 0? strain gauge in normal condition.

[0025] The above description is preferred embodiments of the invention only. It shall be pointed out that many improvements and modifications can be made by one of ordinary skill in the technical field without departing from the principle of the invention, which shall also be regarded as falling within the scope of protection of the invention.