Patent Application
20130136816
The invention relates to an apparatus for non-destructively inspecting a conveyor belt in a manufacturing facility. The conveyor belt has a carrying-side cover plate and a running-side cover plate each made of a rubber mixture and has an embedded tension member. The manufacturing facility comprises at least the following facility components: a vulcanizing press including an upper platen and a lower platen, which can be heated; a first winding unit for the unvulcanized conveyor belt blank, which is fed to the vulcanizing press by unwinding; a second winding unit, which receives and rolls up the vulcanized conveyor belt after it has left the vulcanizing press; carrying rollers for the conveyor belt; and, a process computer.
In relation to the structure of a conveyor belt, reference is made in particular to the following patent literature: DE 25 20 943 A1; DE 25 32 190 A1; DE 38 01 120 A1; U.S. Pat. No. 5,460,261; DE 44 36 042 A1; EP 0 336 385 A1; U.S. Pat. No. 5,609,242; and, WO 2008/034483 A1.
The carrying-side cover plate and running-side cover plate each comprise a rubber mixture, containing a rubber component or a rubber component blend, a wetting agent or a wetting system comprising a wetting agent and an accelerator, and usually further mixture ingredients, in particular a filler and/or a processing aid and/or an ageing prevention agent and/or a plasticizer and/or other additives (for example, fibers, colored pigments). The relevant rubber base is in particular:
natural rubber (NR)
butadiene rubber (BR)
chloroprene rubber (CR)
styrene-butadiene rubber (SBR)
nitrile rubber (NBR)
butyl rubber (IIR)
ethylene-propylene rubber (EPM)
ethylene-propylene-diene rubber (EPDM)
SBR/NR blend
SBR/BR blend
NR/BR blend
Of particular importance until now was CR, which is distinguished by high resistance to flame, weathering and ageing, in particular for conveyor belts with use in underground mining. Nowadays, major importance is assigned to the material base SBR/NR.
As a result of the vulcanization of a rubber mixture of the aforementioned type, the conveyor belt experiences the necessary elastic properties.
The embedded tension member or reinforcement used is cords made of steel or aramid extending in the conveyor belt longitudinal direction, cords made of steel being of particular importance. In particular in conjunction with steel cord conveyor belts, embedded transverse reinforcement made of synthetic cords, for example of polyamide (PA), is additionally used for the purpose of split prevention (WO 2008/034483 A1). The tensile member or reinforcement can also be a textile fabric, in particular a single-layer or multilayer fabric, for example a polyester-polyamide fabric.
In addition, the following components can also be embedded in the carrying-side and/or running-side cover plate/s: conductor loops, transponders, bar codes, a polymer matrix with detectable particles mixed in or other detectable elements. In this regard, reference is made in particular to the following patent literature: DE 44 44 264 C1; DE 197 15 703 A1; U.S. Pat. No. 7,954,632; and, U.S. Pat. No. 6,781,515.
During the production of a conveyor belt, in addition to the visual monitoring, process-controlled devices for monitoring production areas are also used, for example when monitoring the vulcanization temperature.
In DE 10 2009 003 458 A1, a recent development for monitoring the cord tension of a steel cord conveyor belt during the production thereof is described. The monitoring device comprises at least the following components: a clamping device, which clamps all the cords; a measuring device, which monitors the cord tension of each cord; and, a cord tensioning device which, following evaluation of the measured results from the measuring device, is capable of performing re-tensioning individually as required on each cord.
Here, the measuring device is a sound level measuring station which is equipped with at least one sound pick-up which, for each coil that is set in oscillation, measures a change in the oscillation frequency and therefore, by comparison of the sound level, a change in the cord tension.
In past years, however, most development work has been invested in monitoring a running conveyor system which, given troughed or closed conveyor belt guidance, can extend over several kilometers. In particular, opto-electronic monitoring systems and radiation monitoring systems were used. These systems are described in the patent publication listed below.
An object of the invention is, then, to provide a generic apparatus in such a way that all conveyor belt-specific data and also defects during the production of a conveyor belt can be detected reliably herewith.
This object is achieved in that a housing is arranged upstream and/or downstream of the vulcanizing press and is provided with two housing openings through which the conveyor belt runs without contact, wherein a radiation source emits rays within the housing in the direction of the surface of the conveyor belt. These rays contain such a high amount of energy that they pass through the conveyor belt. A sensor likewise accommodated in the housing detects the rays which have passed through without contact. The process computer finally evaluates the result of the radiographic check by detecting the actual values and comparing the same with the nominal or set values of the conveyor belt.
The radiation source emits especially x-rays and here, the radiation source is in the form of an x-ray tube. Within the housing, the radiation source is arranged in such a way that the belt surface can be covered by the rays in accordance with the following two variants I or II described below.
The radiation source covers the entire conveyor belt width. This is preferably the case when the conveyor belt is not excessively wide, for example up to 1000 mm.
Large overland conveyor belts are generally up to 2800 mm wide. Since, in particular, the x-ray tubes are relatively expensive, the conveyor belt is divided up into longitudinal strips when a single x-ray tube is used. If, for example, the conveyor belt has a width of 2000 mm, then this is divided up into four longitudinal strips each having a width of 500 mm. As soon as each strip has been examined and evaluated, the x-ray tube is displaced by 500 mm. A 2000 mm wide conveyor belt would then be recorded completely over its entire width in four steps.
Opposite the radiation source, that is, on the other side of the conveyor belt, the rays are detected by sensors which also comprise light-sensitive chips. In order to obtain a good resolution, for example of 3 mm, line sensors are preferably used. The sensor can also act as an individual sensor or as a sensor chain. The dimension of a sensor depends in particular on according to which of the two aforementioned Variants I or II the radiation source covers the extent of the conveyor belt width. In the case of Variant II, a displaceable sensor can be used.
The intensity of the received rays in conjunction with the subsequent evaluation of the gray values by means of specific image processing software permits conclusions to be drawn about the condition of the conveyor belt.
The data from the points deviating from the satisfactory condition of the conveyor belt is finally evaluated in real time and automatically leads to fault messages, for example via individual threshold value data filters. In addition, the data is evaluated graphically.
By using the apparatus of the invention, the following data can be acquired:
(a) detection of cord defects, edge defects and other damage; and,
(b) detection of the cord pitch, cord position, inclusions (air, foreign bodies), belt width, belt thickness, position and condition of the transverse reinforcement, fabric butt joints, (longitudinal and transverse), position and condition of integrated components (conductor loops, transponders, bar codes, et cetera).
The invention will now be described with reference to the drawings wherein:
A radiation source 9, in particular in the form of an x-ray tube, is accommodated within the housing 7. The radiation source with its high-energy rays 10, in particular in the form of x-rays, covers the carrying-side cover plate 5. With regard to the measurement, reference is made to the two Variants I and II described herein. A sensor 11, which is arranged in the immediate vicinity of the running-side cover plate 6, detects the rays 10 that have passed through, without contact (that is, without any wear). The sensor is formed in particular in this case as a line sensor. A process computer 30 finally evaluates the result of the radiographic check, for example the extent of the air inclusions 8.
As
For large overland conveyor belts, which are generally up to 2,800 mm wide, the conveyor belt 4 can be thought of as being divided up into several longitudinal strips. The x-ray tube is displaced by incremental amounts so that the longitudinal strips are covered sequentially. Thus, referring to
The unvulcanized conveyor belt blank is stored on a first winding unit 16 following its production. When unwinding the conveyor belt 17, this blank is fed to the vulcanizing press 13 in the running direction (arrow direction) for the purpose of vulcanization.
Upstream of the vulcanizing press 13, there is arranged a housing 18, as described in more detail within the context of
A second winding unit 19 finally receives the vulcanized conveyor belt by rolling the latter up. This rolled up and finished conveyor belt can then be transported to its location of use on a conveyor system.
During the entire production operation between the first winding unit 16 and the second winding unit 19, the conveyor belt 17 outside the vulcanizing press is guided on carrying rollers 20 and 21 or on a roller system. With regard to the winding technique for the conveyor belt, reference is made, for example, to the teaching according to U.S. Pat. No. 7,438,252 incorporated herein by reference.
The housings 18 (
It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2010 036 637.4 | Jul 2010 | DE | national |
This application is a continuation application of international patent application PCT/EP2011/056537, filed Apr. 26, 2011, designating the United States and claiming priority from German application 10 2010 036 637.4, filed Jul. 27, 2010, and the entire content of both applications is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP2011/056537 | Apr 2011 | US |
| Child | 13751827 | US |
