CS65592A3 - Apparatus for measuring clearance between rolls - Google Patents

Abstract

The present invention relates to an apparatus for determining a roll gap for a pair of rolls, in particular for milling plant roll frames, having at least one magnetic field sensor for a magnetic field formed between the rolls of the pair of rolls, the pair of rolls being provided with a permanent magnet arrangement (5.1 to 5.4) for generating the magnet field in the roll gap. <IMAGE>

Description

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Roll distance measuring device

Technical field

The invention is used in measuring the distance between the cylindrical sleeve and relates to a device for measuring the distance between the rollers of a pair of rollers, which consists of a source forming a magnetic field in a rolling gap and a measuring head located thereon which is mounted on the front side. rollers.

BACKGROUND OF THE INVENTION In plants equipped with a twin cylinder, it is often desirable for a technically smooth process to determine the distance between the intermediate rolls. In addition to the mechanical, optical, capacitive and other means, electromagnetic means are also used. These have the advantage that a sensor such as a Helium probe can be relatively easily evaluated for the signal to be delivered.

Such a solution is apparent from DE-AS 16 23 127. Here, a wall can be disposed on the rolling friction arm of the roller between the rollers. This fork is also designed so that it can follow the change in the position of the rollers and thus the change in roll distance. A probe carrier is located in the transverse bridge between the two fork halves. This carrier carries two measuring probes that are positioned symmetrically to the measuring axis passing through the centers of the cylinders.

The probe carrier consists of a non-magnetic material. In the probe circuit, pole pieces are provided on the carrier which determine the direction of the magnetomotor force. However, the electromagnetic induction may also be formed by two coils flowing through a current arranged symmetrically to the measurement axis. If sufficient measurement accuracy is to be achieved, the air gap between the cylinder surface and the pole piece, or between the roller surface and the coil pole, must be as low as possible. * For AC voltage devices, a magnetically displaced over the pole pieces or coil, an air gap, and a cylinder are created. This field is sensed by the sensor. A change in the position of the cylinder causes a change in the magnetic field, registers and is evaluated electronically.

The disadvantage is that the solution is difficult to use and technically manageable.

The essence of this is that large magnetic induction must be achieved. This is achievable when the weight of the rollers is very large and the material of the rollers, generally of hardened cast iron, is my unfavorable magnetic properties. This solution is not applicable in various application areas such as mills. '- · ·, .......'; ..... 5 ·;

High, induction. Causes the risk of an electric discharge causing an explosion.

SUMMARY OF THE INVENTION

The invention is based on the development of a device which can measure the distance of the cylinders by magnetic sensors without achieving a great magnetic induction. ....,

This object is solved by the knowledge of claim 1). The advantage of the invention is that the magnetic flux is obtained by a permanent magnet and not by an electromagnet. This allows for a small current requirement and for insertion into explosion-proof devices. The cost of the equipment is negligible and existing equipment can be modified.

This is achieved in practice by spot metering, - deviations occurring, in particular, by the rotation of the rollers. The progress of the distance of the rollers is thus observed by the fiefs. i f

BRIEF DESCRIPTION OF THE DRAWINGS The invention is further illustrated by the following examples. The following drawings have the following meaning: FIG. 1 shows a schematic representation of the measuring head and the permanent magnets FIG. 2 shows the construction of the measuring head FIG. 3 shows the front faces of the cylinders FIG. Magnets at the time of measurement. -,?

In the Examples, 4

As can be seen from FIG. 1, the twin cylinder consists of two protruding cylinders 1. The small spacing between the cylinder shells 2 forms a rolling gap 3. The cylinders 4 have at least one permanent magnet 5 and are also possible variants with two or more permanent magnets 5-

Permanent magnets, which are located at the edge of the end faces, are at the greatest possible distance from the rotational axes of the cylinders 1, thereby creating a locally limited magnetic field. Therefore, the permanent magnets 5 in the groove are fixed. This is accomplished by an adhesive or other reliable bond. Conventional permanent magnets 5 which contain ceramic molding are used. The weight of the permanent magnets J1 is very low compared to the weight of the rollers.

According to the invention, the poles of the same name are permanent magnets. optionally 9 * 3. 9.4, formed on a single cylinder 1.1 or 1.2, arranged opposite. This condition is the same for both cylinders 1.1, 1.2. The second condition is that the permanent magnets 5 of the co-operating rollers are arranged, with the non-identical poles facing each other. If, as shown in FIG. 1, one pole Nd is formed inside the cylinder 1.1, then this cylinder N1 is formed on the outside.

Both cylindrical faces 4.1 and 4.2 and 4.3 and 4.4 are provided with measuring heads 6 of the same type. These measuring heads 6 are mounted on the housing 7 of the rolling machine. The measuring heads 6 are formed at the height of the rolling gap, which is specifically to extend the line, which is achieved by contacting the two cylinders 1.1, 1., 2.

FIG. 2 illustrates an embodiment of a measuring head 6. This measuring head 6 consists of two magnetic field sensors 8 which are connected to each other on a platinum plate 9. Two magnetic field sensors 8 are used to increase the sensitivity. can at the same time achieve another. temperature compensation.

Between the magnetic field sensors 8, a ferrite element 10 is formed to stack magnetic field lines and thereby to increase the sensitivity. The Hall sensor is preferably used as the magnetic field sensor 8.

FIG. 3 shows the front surface of 4 cylinders of a twin cylinder. The direction of movement of the cylinders 1.1, 1.2 is indicated. It is clear from this schematic representation that the permanent magnets orbit the rotary axes in a circular motion. The rotational speeds of the cylinders 1.1, 1.2 are different for technical reasons, which allows the relative movement of the roller sections 2.1 ', 2.2 and thereby grinding or spreading. This occurs after the speed difference depending on the situation shown in FIG. permanent magnets 9 are facing each other. As already explained in FIG. 1, it generates a short-term magnetic field whose line of force is determined by the vector sum of the two magnets standing opposite each other and is dependent on the distance of the rollers 1, that is, on the rolling gauge. , which is processed on a suitable evaluation unit and output as digital information about the roll gap 3,

Claims (4)

I - 6 PATENT CLAIMS the head (6) is located at the height of the rolling gap (3). the edge of the front face (4) of each cylinder is provided with at least one permanent magnet (5), and at the end faces (4) of one cylinder C1, 1.2. the permanent magnets (5.1, 5 · 2, 5 · 3, 5 · 4), the same-name poles, are located on the opposite faces (4.1, 4.2) of the co-acting cylinders (1.1, 1.2). magnets (5.1.5.2, 5 · 3, 5 * 4). 2. Apparatus according to claim 1, characterized in that the permanent magnets (5) are formed with a weight which is relatively small in relation to the weight of the rollers (1). 3) Apparatus according to claims 1, 2, characterized in that the male magnets (5) are formed in a plane passing through the axis turning the cylinder (1). 4) Device according to claims 1 to 3), characterized in that the permanent magnets (5) are glued in the groove in the cylinder end face (4). r ASSO