FI73831C - GIVARE FOER MAETNING AV MEKANISKA EGENSKAPER HOS EN ROERLIG AEMNESBANA. - Google Patents

Description

73831

SENSOR FOR MEASURING THE MECHANICAL PROPERTIES OF A MOVING MATERIAL - GIVARE FÖR MÄTNING AV MEKANISKA EGENSKAPER HOS EN RÖRLIG ÄMNESBANA

This invention relates to the continuous measurement of mechanical dimensions, such as thickness, of a moving web of material, such as a paper web.

5 The quality of the paper web coming from the paper machine is monitored by various sensors that measure the reluctance of the magnetic gap (air gap) depending on the mechanical dimensions of the paper web, such as the thickness, which is a measure of that quantity.

10

For example, the CALITEL 11R sensor and the method for measuring the thickness of the moving material web coating material GB 2 147 423 based on inductive measurement are previously known. This sensor is placed in a carriage moving in the width direction of the paper web, so that it can be moved over the entire width of the paper web 20.

However, it has been found that such a sensor does not perform measurements at all paper machine speeds or grades without causing holes in the paper web, especially unpolished, because the pressure of the sensor levels against the web must be kept to a certain level to obtain a reliable measurement result.

When such a pressure is loaded on the paper web, the resin spot or other particle therein, when in the 73831 range, generally tears the triangular tab from the web. Such pressure also provides a strong surface temperature on the sensor surfaces in contact with the web due to friction. The high temperature helps 5 resin spots or other particles to adhere to the sensor surfaces.

At low sensor pressures, differences in the standard laboratory test due to web roughness variations and corrugations occur when the track is loaded.

It is an object of the present invention to provide a sensor for measuring the thickness of a moving web of material such as paper in a manner in which the above-mentioned drawbacks are eliminated. To achieve this, the device according to the invention is characterized by what is set forth in the characterizing part of claim 1.

The mechanical stresses acting on the web of the sensor according to the invention are so large and parallel that they do not damage the web with certainty.

It is a further advantage of the invention that by adjusting the pressure of the sensor part against the web appropriately, it is possible to obtain directly consistent measurement results with laboratory assays carried out in accordance with the standard, and that the sensor part does not require expensive special components.

30 In the following, the center is described in detail with reference to the drawings, in which:

Figure 1 shows a side view of the sensor with respect to the direction of travel of the web and the connection of the sensor 35 to the electronic part.

Il 3 73831

Fig. 2 shows a sectional view taken in the direction I-I of Fig. 1.

The sensor according to Figures 1 and 2 comprises a drum mounted according to Figure 2 attached to the frame 14 below the web 5 of the carriage by the arms 13 and a sensor part 1 attached to the frame 10 above the carriage by means of the arms 3, 4 and the joints 5.

A magnetoresistive component 2 is preferably embedded in the sensor part 1 and a signal conductor 7 is conveyed therefrom in a certain way to the electronic unit 8, which gives the display part 9 a suitably scaled signal, e.g. mV / micrometer.

15

The pressure of the sensor part 1 against the web 15 can be adjusted to suit by using e.g. a spring 6.

The drum 11, which contacts the web of the sensor from below, is non-magnetic and has a rail 12 of suitable width made of magnetic material in its axial direction.

As the web 15 travels between the sensor drum 11 and the sensor 1 25 in the direction 16, the sensitively mounted drum 11 obtains a circumferential speed 17 corresponding to the web motion. Thus, as the drum 11 rotates, the magnetic rail 12 bypasses the magnetoresistive component 2 dependent on the passing distance, i.e. the thickness of the web.

The material of the sensor 1 is very wear-resistant, such as "robadur" (= Trade name of the material).

4,73831

If it is desired that the sensor 1 does not make direct contact with the web 15, e.g. for reasons due to the sensor material, the sensor part 1 can be raised to a suitable distance from the web 15 (e.g. 0.1 mm) by a sensitive rotating roller preferably attached to the Senso-5. contact the web and obtain a circumferential speed corresponding to its speed of movement.

Il

Claims (2)

5,73831 A sensor for measuring the thickness of a moving material web with a material web (15) running between a sensor part (1) and a rotating drum (11), characterized in that a rail of magnetic material is embedded in the surface of the rotating drum (11) 12) which, bypassing the magnetoresistive component (2) embedded in the sensor part 10 (1) by a thickness-dependent distance of the web (15), causes said distance-dependent change in the magnetic flux acting on the component (2), the magnitude-dependent change in the resistance , which is for the thickness of the measuring web (15). Sensor according to Claim 1, characterized in that the sensor part (1) is provided with a rotating roller which is preferably attached to it.