Measuring apparatus

Abstract

To provide a measuring apparatus capable of reducing cleaning frequency of a sensor.SOLUTION: A measuring apparatus installed in a paper machine for measuring a quality of a paper machined by the paper machine includes a sensor contacting with at least one face of the moving paper, a head part installed with the sensor and scanning the sensor in a direction crossing with a movement direction of the paper, and an air ejection part for ejection of an air to the sensor while the head part is moving outside of both end parts of the paper in the width direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a measuring device for measuring the quality of paper made by a paper machine. [Background technology]

[0002] A BM meter (Basis Weight & Moisture Measurement System) is installed on a paper machine as a measuring device for online measurement of the quality of paper made by the paper machine, such as basis weight, moisture content, ash content, and thickness. The BM meter continuously measures paper thickness and other parameters during the papermaking process by scanning a head equipped with various sensors, such as a caliper (paper thickness) sensor, across the width of the paper (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2-287245 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the caliper sensor of the BM meter (measuring device) mentioned above had the problem that a large amount of pitch, a sticky foreign substance, adhered to the contact part of the paper surface, and this adhesion would peel off, causing paper waste and joints.

[0005] Therefore, cleaning to remove pitch is usually performed approximately every eight hours, but depending on the type of paper, a large amount of pitch can accumulate in a short period of time, so cleaning was required every 10 to 20 minutes.Since scanning with the BM meter was not possible during cleaning, the number of measurements was insufficient, and as a result, there was a risk of missing an abnormality in the paper thickness profile.

[0006] An object of the present invention is to provide a measuring device that can reduce the frequency of cleaning the sensor. [Means for solving the problem]

[0007] The present inventors have completed the present invention in order to solve the above problems. The present invention provides the following. (1) A measuring device that is installed in a papermaking machine and measures the quality of paper made by the papermaking machine, characterized in that it comprises a sensor that contacts at least one side of the moving paper, a head unit that mounts the sensor and scans the sensor in a direction intersecting the moving direction of the paper, and an air injection unit that injects air into the sensor while the head unit is moving outside both ends of the width direction of the paper. (2) The measuring device according to (1), wherein the air injection unit is installed outside both ends of the paper in the width direction. (3) A measuring device according to (1) or (2), characterized in that the direction of the air sprayed by the air spray unit is opposite to the direction of movement of the paper, parallel to the direction of movement of the paper, or directed outward from both ends of the paper in the width direction. (4) The measuring device according to (1) or (2), further comprising a guide bar attached to the tip of the air injection part to guide the injection direction of the air injected from the air injection part. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a measuring device that can reduce the frequency of cleaning the sensor. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1A is a front view showing the configuration of a measurement device according to an embodiment, and FIG. 1B is a cross-sectional view showing the configuration of a measurement device according to an embodiment. [Figure 2] 5A and 5B are diagrams for explaining an injection area onto which the air injection unit in the embodiment injects air. [Figure 3]10A and 10B are diagrams for explaining the positional relationship between an upper head section, a lower head section, and an air ejection section according to the embodiment. [Figure 4] 10A and 10B are diagrams for explaining the positional relationship between an upper head portion, a lower head portion, and a guide portion according to the embodiment. [Figure 5] 10A and 10B are diagrams for explaining an injection area to which air is injected by an air injection unit according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] A measuring device according to an embodiment of the present invention will be described below with reference to the drawings. The measuring device according to this embodiment is, for example, a BM meter (Basis Weight & Moisture Measurement System) installed on a paper machine, and measures the quality of paper produced by the paper machine, such as basis weight, moisture content, ash content, and thickness, online. FIG. 1(A) is a front view showing the configuration of the measuring device according to this embodiment, and FIG. 1(B) is a cross-sectional view taken along the line AA in FIG. 1(A). In the following, an XYZ Cartesian coordinate system is set as shown in FIG. 1, and the positional relationship of each part will be described with reference to this Cartesian coordinate system. The X axis is set in a direction perpendicular to the plane of FIG. 1(A), the Y axis is set in the left-right direction on the plane of FIG. 1(A), and the Z axis is set in the up-down direction on the plane of FIG. 1(A).

[0011] As shown in Fig. 1, the measuring device 2 according to this embodiment includes vertical frames 4 and 6 with their longitudinal direction in the Z direction, and horizontal frames 8 and 10 with their longitudinal direction in the Y direction. The vertical frame 4 is disposed on the -Y direction side, which is the anti-maintenance side, and the vertical frame 6 is disposed on the +Y direction side, which is the maintenance side. The horizontal frame 8 is disposed on the +Z direction side, and the horizontal frame 10 is disposed on the -Z direction side. Paper 18 produced by a papermaking machine (not shown) moves from the -X direction to the +X direction within the frame formed by the vertical frames 4 and 6 and the horizontal frames 8 and 10.

[0012] The measuring device 2 also has an upper head unit 12 on the +Z direction side and a lower head unit 14 on the -Z direction side. The upper head unit 12 is attached to a horizontal frame 8 and is movable in the ±Y directions along the horizontal frame 8. The lower head unit 14 is attached to a horizontal frame 10 and is movable in the ±Y directions along the horizontal frame 10. The lower head unit 14 is equipped with a caliper sensor 16 (see FIG. 2) for measuring paper thickness and sensors (not shown) for measuring basis weight, moisture content, etc.

[0013] The upper head unit 12 and the lower head unit 14 move in the -Y direction from the maintenance side while facing each other, then move further in the -Y direction while sandwiching the paper 18 moving in the +X direction, and when they reach the anti-maintenance side, they move in the +Y direction from the anti-maintenance side, and then move further in the +Y direction while sandwiching the paper 18 moving in the +X direction. In this way, the upper head unit 12 and the lower head unit 14 repeatedly scan the caliper sensor 16 and other components in the ±Y directions between the maintenance side and the anti-maintenance side. While the lower head unit 14 moves along the -Z side of the paper 18, the caliper sensor 16 comes into contact with the surface of the paper 18 on the -Z side to measure the paper thickness of the paper 18.

[0014] The measuring device 2 is equipped with an air injection unit 20 on the anti-maintenance side (-Y direction side). When the upper head unit 12 and the lower head unit 14 are moving in the ±Y directions and the caliper sensor 16 approaches the air injection unit 20, as shown in FIG. 2, the air injection unit 20 injects air toward the caliper sensor 16, i.e., in the -X direction, which is the opposite direction to the movement of the paper 18. Pitch adheres to the caliper sensor 16 due to contact with the paper 18. The air injection unit 20 injects air between the upper head unit 12 and the lower head unit 14 to blow away the pitch adhered to the caliper sensor 16. The shaded area in FIG. 2 indicates the direction and area of ​​air injected by the air injection unit 20. The air injection unit 20 is installed in a position where air is injected into an area where pitch blown away from the caliper sensor 16 will not be mixed into the paper 18. Specifically, since the air is diffused over a width of 200 to 300 mm, it is desirable to install the air ejection unit 20 at a position 300 mm or more away from the edge of the paper 18 in the -Y direction.

[0015] It is desirable that the air injection unit 20 be fixed in a position that does not interfere with the movement of the upper head unit 12 and the lower head unit 14 when the upper head unit 12 and the lower head unit 14 approach the air injection unit 20, and that can blow away the pitch sufficiently and reliably, and that can reliably inject air into the gap G (see Figure 3) between the upper head unit 12 and the lower head unit 14. Depending on the thickness of the pipe constituting the air injection unit 20 relative to the gap G, for example, if the pipe constituting the air injection unit 20 is rigid, the tip of the air injection unit 20 is installed near the gap G between the upper head unit 12 and the lower head unit 14 as shown in Figure 3(A), at a position inserted into the gap G between the upper head unit 12 and the lower head unit 14 but not in contact with the upper head unit 12 and the lower head unit 14 as shown in Figure 3(B), at a position inserted into the gap G between the upper head unit 12 and the lower head unit 14 but in contact with the lower head unit 14 as shown in Figure 3(C), or at a position inserted into the gap G between the upper head unit 12 and the lower head unit 14 but in contact with the upper head unit 12 (not shown).

[0016] Furthermore, for example, if the diameter of the pipe that constitutes the air injection unit 20 is smaller than the gap G and the pipe that constitutes the air injection unit 20 does not have rigidity, a configuration may be provided that includes a guide unit 22 that guides the air injection direction, as shown in Fig. 4. The guide unit 22 includes two guide bars 22a and 22b attached to the tip of the air injection unit 20. The guide bar 22a is attached to the +Z direction side of the air injection unit 20, and the guide bar 22b is attached to the -Z direction side of the air injection unit 20. Inserting the guide bars 22a and 22b between the upper head unit 12 and the lower head unit 14 prevents the position of the air injection unit 20 relative to the caliper sensor 16 from shifting, and therefore prevents the air injection direction from shifting. Depending on the thickness of the pipe constituting the air injection section 20 for the gap G, in addition to being inserted at a position where the guide bar 22a is not in contact with the upper head section 12 and the guide bar 22b is not in contact with the lower head section 14 as shown in Figure 4, the guide bar 22a may be inserted at a position where it is in contact with the upper head section 12 or the guide bar 22b may be inserted at a position where it is in contact with the lower head section 14.

[0017] Furthermore, to prevent the air injection unit 20 from contacting and damaging the upper head unit 12 and the lower head unit 14, the pipe that constitutes the air injection unit 20 may be made of a non-rigid plastic material, and to enable adjustment of the air injection direction, the pipe may be covered with a tube and wired on the outside. Furthermore, a sludge receiver (not shown) that receives pitch blown away by air injection from the air injection unit 20 may be provided on the -X direction side of the measuring device 2, i.e., on the upstream side of the paper machine.

[0018] Although the air injection unit 20 according to this embodiment is installed outside the −Y side edge of the paper 18 in the width direction, which is the side opposite to maintenance, it may also be installed outside the +Y side edge of the paper 18 in the width direction, which is the maintenance side. Furthermore, the air injection unit 20 according to this embodiment has its tip facing the −X direction and injects air in the −X direction, but the direction in which air is injected by the air injection unit 20 may be any direction opposite the direction of movement of the paper 18 and outward from the −Y side edge of the paper 18 in the width direction. For example, as shown in FIG. 5, the tip of the air injection unit 20 may be oriented from the −X direction toward the outward from the −Y side edge of the paper 18 in the width direction, and the area injected by the air injection unit 20 may fall within the shaded area in FIG. 5.

[0019] The measuring device 2 according to this embodiment is equipped with an air injection unit 20, which allows pitch adhering to the caliper sensor 16 to be removed by blowing it away with air. This reduces the frequency with which the caliper sensor 16 needs to be cleaned, and maintains high measurement accuracy for the caliper sensor 16. It also prevents the occurrence of broken paper and splices due to pitch peeling. Furthermore, because the air injection unit 20 is installed outside the −Y-direction end of the width direction of the paper 18, pitch adhering to the caliper sensor 16 can be removed while the caliper sensor 16 is not measuring the paper thickness of the paper 18, and does not interfere with the paper thickness measurement by the caliper sensor 16.

[0020] Furthermore, the direction in which air is sprayed from the air spray unit 20 is opposite to the direction of movement of the paper 18, and is parallel to the direction of movement of the paper 18 or directed outward from the widthwise end of the paper 18, i.e., the area indicated by diagonal lines in Figure 5, so that pitch blown by the air can be prevented from mixing into the paper 18.

[0021] Furthermore, a defect detector that detects defects such as holes, foreign objects, and stains in the paper 18 is usually installed on the +X side of the measuring device 2 (downstream of the paper machine), but if the air injection unit 20 injects air in the same direction as the paper 18 moves, and pitch blown by the air further in the +X direction than the defect detector gets mixed into the paper 18, the defect detector will no longer be able to detect the mixed object. However, because the air injection unit 20 in this embodiment injects air in the opposite direction to the moving direction of the paper 18, even if pitch blown by the air gets mixed into the paper 18, the defect detector can still detect the mixed object.

[0022] In the above embodiment, a semi-contact sensor has been described as an example in which the lower head unit 14 is provided with the caliper sensor 16 and the caliper sensor 16 comes into contact with one side of the paper 18, but the present invention can also be applied to a double-sided contact sensor in which the upper head unit 12 and the lower head unit 14 each have a sensor, the two sensors face each other, and one sensor comes into contact with one side of the paper 18 and the other sensor comes into contact with the other side of the paper 18. In this case, the air injection unit 20 blows away the pitch adhering to each of the opposing sensors with air, thereby simultaneously removing the pitch adhering to both sensors. [Explanation of symbols]

[0023] 2...measuring device, 4,6...vertical frame, 8,10...horizontal frame, 12...upper head portion, 14...lower head portion, 16...caliper sensor, 18...paper, 20...air injection portion, 22...guide portion, 22a,22b...guide bar.

Claims

1. A measuring device that is installed in a paper machine and measures the quality of paper made by the paper machine, a sensor contacting at least one surface of the moving paper; a head unit that includes the sensor and scans the sensor in a direction intersecting the moving direction of the paper; an air injection unit that injects air at the sensor while the head unit is moving outside both ends of the paper in the width direction; A measuring device comprising:

2. 2. The measuring device according to claim 1, wherein the air ejection units are installed outside both ends of the paper in the width direction.

3. 3. The measuring device according to claim 1, wherein the direction of the air ejected by the air ejection unit is opposite to the direction of movement of the paper, and is either parallel to the direction of movement of the paper or directed outward from both ends of the paper in the width direction.

4. 3. The measuring device according to claim 1, further comprising a guide bar attached to a tip of the air injection unit for guiding the injection direction of the air injected from the air injection unit.

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