LU103156B1 - Diameter measurement for wear-prone components - Google Patents

Abstract

The present invention relates to a method for detecting the diameter of a component 10 which is subject to wear in order to detect the condition and the need for replacement at an early stage.

Description

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Diameter measurement for wear-prone components

The invention relates to a method for detecting the diameter of a component which is subject to wear in order to determine the condition and the need for

exchange at an early stage.

An example of wear-prone components with a rotationally symmetrical design are grinding media in a vertical roller mill, a crusher roller,

Grinding roller, kiln running rings or kiln running rollers. Wear on the running surface removes material, so that the diameter decreases steadily, albeit slowly, during operation. The wear and thus the prognosis for the further

Usability is therefore determined by measuring the scope or

diameter is most efficient.

Nowadays, during maintenance, a measuring tool with a measuring wheel with a precisely known circumference is often attached to the object to be measured and the circumference is determined in this way. The disadvantage of this method is that the requirement for the

measuring wheel are very high and the positioning of the measuring tool must be very precise. This makes the measurement time-consuming and can only be carried out by specially trained

Personnel is possible. Another current option for diameter determination is the

Measurement with gauges that have to be attached to grinding media with enormous expenditure of time.

A wear measurement is known from WO 2022 / 023 869 A1.

From EP 0 509 809 A2 a device and a method for detecting wear on a crusher roller are known.

The object of the invention is to provide a method which

Wear detection in a simple way, especially in the case of inaccurate

Placement of a detection device is possible, thus enabling detection even by untrained or only slightly trained personnel.

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This object is achieved by the method with the features specified in claim 1

Features. Advantageous further developments emerge from the subclaims, the following description and the drawings.

The method according to the invention serves to detect wear via the

Determination of the circumference or diameter of a rotationally symmetrical component subject to wear. Circumference, diameter and

Radius are only directly mathematically connected to each other via the constants 2 and/or TT and can therefore be exchanged for each other or converted into each other at will. It is therefore equivalent whether, for example, a minimal

Radius rmin, a minimum diameter dmin = 2 rmin or a minimum circumference Umin = TT dmin = 2TT min is specified at which the component is to be replaced, for example.

Examples of rotationally symmetrical wear-prone components are

Grinding and crushing rollers as well as running rings and rollers. These components can be more disc-shaped, as in a vertical roller mill, or more elongated, for example in a crusher. It is essential that the component has a rotationally symmetrical basic shape and that the wear on the outer surface of the

cylinder jacket.

The method comprises the following steps: a) _Contactless detection of surface points of at least a first part of the surface of the component, b) Determination of at least two ellipses intersecting the component and determination of the

Centers of the ellipses, ©) Determining the cylinder axis of the rotationally symmetrical component from the centers determined in step b), d) Determining the cylinder diameter or the cylinder circumference from the cylinder axis determined in step c) and the

surface points.

At first, the process seems unnecessarily complex. It would be much easier if the detection were carried out perpendicular to the surface of the component. However, this requires exact positioning. However, this process makes it possible to

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Neither distance nor angle to the surface must be maintained or determined. This makes this method particularly suitable for untrained or only slightly trained personnel

to be used by personnel.

In a further embodiment of the invention, the contactless detection takes place in

Step a) optical. The non-contact detection in step a) is particularly preferably carried out using a line laser. This does not require precise calibration, as is the case with a mechanical measuring instrument, for example. Such devices for surface detection are commercially available and therefore comparatively inexpensive.

In a further preferred embodiment of the invention, the detection takes place in

Step a) for example during maintenance or cleaning work, i.e. only temporarily.

Especially in mills and crushers, the dust pollution speaks against permanent

Setting up the recording device and the continuous execution of the

procedure, even if this would be advantageous in principle.

In a further embodiment of the invention, the detection in step a) is carried out continuously. The detection device is thus permanently integrated. The advantage is that a misalignment, for example due to vibrations, has no negative influence on the

measurement result.

In a further embodiment of the invention, the component is detected in

Step a), preferably at a constant speed. This will produce more

Data points are recorded. For example, and preferably, a complete rotation of the component is detected by wear points, for example, point-like

Depressions, scratches or the like. These characteristic points can be found again after a full rotation and can thus be used as a marker. In addition, it can also be checked whether a sufficient portion of the rotationally symmetrical component is detected by the detection device.

In a further embodiment of the invention, the detection of the

Surface points allow edge detection of the component and measuring points outside the

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Component are eliminated before further processing. In the simplest case, the

Measuring points outside the actual component to be measured are significantly further away.

The edge can thus be clearly seen from the jump in distance from the detection device. All data points with a distance that is clearly too large are eliminated. This is also applicable to objects that are located between the

detection device and the component, for example a hanging

Rope. Here, the distance is too short, which indicates that this does not belong to the component and these data points can therefore also be removed more easily.

In a further embodiment of the invention, the values of the surface points recorded in step a) are examined for deviating extreme values before further processing. Such extreme values can arise, for example, from metallic reflections or the like. This results in measurement values that are meaningless and clearly stand out from the rest of the set of points. These deviating extreme values are then replaced by the average of the neighboring surface points. These

Approximation leads to much better results than using the

extreme values.

In a further embodiment of the invention, the values of the surface points recorded in step a) are checked to ensure that a sufficient part of the surface is recorded. This is intended to prevent only a part of the surface that is too small from being recorded, which may show little or no wear.

The method according to the invention is explained in more detail below using embodiments shown in the drawings.

Fig. 1 Device

Fig. 2 Ellipses

Fig. 3 Cylinder axis

Fig. 4 cylinder

Fig. 5 Second example

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Fig. 1 shows how a rotationally symmetrical component 10, for example a

grinding roller, is detected by a detection device 20, here a line laser. The

Positioning can be done relatively freely. For example, it does not have to be arranged exactly perpendicular to the rotationally symmetrical component. Therefore, the detection device 20 can be positioned very easily even by untrained or only slightly trained personnel.

The laser detects the surface point by point. Since the rotationally symmetrical component 10 is not as isolated in reality as shown here, edge detection 10 is useful in order to recognize points that are too far to the front or back as no longer belonging to the component 10. In the example shown, three rows of points are shown on the

Surface is detected. This can be done by three detecting lasers or by methods of

detection device 20 can be achieved.

From the point family, ellipses 30 are then calculated as shown in Fig. 2 and the

Center points of the ellipses 30 are determined. The cylinder axis 40 shown in Fig. 3 then follows from the centers. This allows the mathematical cylinder 50, which describes the rotationally symmetrical component 10, to be determined using the recorded set of points, as shown in Fig. 4, and thus the cylinder diameter or the cylinder circumference can be determined and thus the wear (reduction in the

diameter).

In Fig. 5 a second example is shown in which the detection is rotated by 90 ° in contrast to the first example shown in Fig. 1. The detection takes place here approximately in the longitudinal direction of the rotationally symmetrical component 10, which during the

The detection is rotated so that the surface is detected. The further evaluation steps are carried out analogously.

Reference numeral 10 rotationally symmetrical component 20 detection device 30 ellipses

cylinder axis

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cylinder

Claims (8)

230064 P00LU LU103156 1/2 Patent claims 1. Method for detecting wear by detecting the circumference or the diameter of a rotationally symmetrical component (10) subject to wear, the method comprising the following steps: a) contactless detection of surface points of at least a first part of the surface of the component (10), b) determining at least two ellipses (30) intersecting the component (10) and determining the centers of the ellipses (30), c) determining the cylinder axis (40) of the rotationally symmetrical component (10) from the centers determined in step b), d) determining the cylinder diameter or the cylinder circumference from the cylinder axis (40) determined in step c) and the surface points detected in step a). 2. Method according to claim 1, characterized in that the contactless detection in step a) is carried out optically. 3. Method according to claim 2, characterized in that the contactless detection in step a) is carried out with a line laser. 4. Method according to one of the preceding claims, characterized in that the component (10) is rotated during the detection in step a), preferably at a constant speed. 5. Method according to claim 4, characterized in that a complete rotation of the component (10) is detected by wear points. 6. Method according to one of the preceding claims, characterized in that the values of the surface points recorded in step a) are examined for deviating extreme values before further processing and that deviating extreme values are replaced by the mean value of the neighboring surface points. 230064 P00LU LU103156 2/2 7. Method according to one of the preceding claims, characterized in that when detecting the surface points, an edge detection of the component (10) takes place and measuring points outside the component (10) are eliminated before further processing. 8. Method according to one of the preceding claims, characterized in that the values of the surface points detected in step a) are checked for detection of a sufficient part of the surface.