JPH0544776Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a sheet tester that uses ultrasonic waves to non-destructively measure the physical properties of a sheet such as paper.

Conventional technology Regarding a sheet tester that uses ultrasonic waves to measure the physical properties of sheets such as paper, the
No. 50-36998, Japanese Utility Model Publication No. 51-21758, Japanese Patent Publication No. 53-26516, and Japanese Patent Publication No. 54-25434.

Problems to be Solved by the Invention Conventional sheet testers use a pair of ultrasonic transmitter and receiver transducers, both of which are arranged at a prescribed interval on a support plate, which can be raised and lowered, and a sample support body provided under the support plate, which can be rotated around a vertical axis, to measure the characteristics of a sheet sample at prescribed rotation angles. However, when measuring a sheet sample at 10° rotation angle intervals, it is necessary to raise and lower the support plate and rotate the sample support body for each measurement value, and it is difficult to measure the characteristics of the sheet sample at 10° intervals in all directions, i.e.
When measuring at 180°, it takes at least about 80 seconds. When measuring at multiple measurement points at intervals over the entire width of a wide sheet of several meters, the number of samples increases and it is necessary to measure a given size (e.g., 25 cm).
It takes time to prepare samples (such as squares) and therefore a great deal of measurement time is required, and there has been a strong demand for a reduction in measurement time and for continuous measurement across the entire width of wide sheets.

Means for Solving the Problems The present invention uses an ultrasonic transmitting/receiving transducer, measures the propagation velocity of ultrasonic waves in a sheet sample between the transmitting and receiving transducers, and A sheet tester for determining the physical properties of a sheet sample between the two components includes an ultrasonic oscillator, a transmitting switching circuit, multiple pairs of transmitting and receiving transducers, a receiving switching circuit, an ultrasonic receiver, and an amplifier. and a sensor body in which the plurality of pairs of transmitting transducers and receiving transducers are arranged and protruded from the sensor surface of the support board at predetermined center angular intervals on the same circumference, and a sensor body facing the sensor surface. A sheet sample support provided therein, a sheet feeding device that allows a long sheet sample on the sheet sample support to be moved a predetermined distance, and a sheet sample support that moves the sheet sample between the sensor body and the sheet sample support. a clamping device for clamping and releasing;
an output device, the sheet feeding device operating means for feeding the elongated sheet sample a predetermined distance in the longitudinal direction on the sheet sample support, and the elongated sheet sample being transferred to the sensor body and the sheet sample support. the clamping device operating means for clamping and releasing the clamping device between the transmitter and the receiver; the transmitting switching circuit that sequentially switches and transmits the ultrasonic transmission waves from the transmitter to the adjacent transmitting transducer; switching means,
A switching means of a receiving switching circuit that sequentially switches to a receiving transducer facing the transmitting transducer across the center of the circumference and a receiving transducer adjacent to the receiving transducer; input from the receiver via an amplifier; The ultrasonic propagation time of the sample sheet between the selected transmitting transducer and the receiving transducer is sequentially changed to the propagation time for the same distance at the same measurement point of the long sheet sample by the received wave. The calculation is performed at the same measurement point without changing the relative position between the sensor body and the sheet sample.
Calculated propagation times in all 360° directions are calculated for each direction with an angular spacing of 1/2 of the center angular spacing of adjacent oscillators, twice as many as the number of pairs of the plurality of transmitting/receiving oscillators. The minimum value and maximum value of the calculation propagation time group, the orientation angle between the direction of the minimum value and the sheet manufacturing direction (MD),
The direction of the maximum value and the direction perpendicular to the MD (CD)
Calculate the orientation angle with respect to Each means of the calculation analysis output means that sequentially performs similar calculations for calculation propagation times in all directions of 360 degrees, aggregates and organizes the calculation analysis as a profile with each calculation value at each measurement point, and outputs it to the output device. The above-mentioned problems could be solved by using an ultrasonic sheet tester comprising a computer device having the following functions.

Effect Since the present invention has the above-mentioned configuration, by creating only a long sheet sample with a predetermined width over the entire width of the wide sheet to be measured, it is possible to measure the length of the long sheet sample. It is now possible to automatically measure, calculate, and output the physical properties at any position in the width direction (width direction of the sheet) in a 180° direction, that is, in all directions, and continuously over the entire length, and the measurement time is also extremely shortened. I have reached the point where

Example The embodiments shown in the drawings will be described below.

The measurement principle is the same as the conventional one.

The propagation time of ultrasonic waves in a certain direction of a sheet sample is measured, and the relative intensity of the sheet sample in the measurement direction is determined.

Now, if the Young's modulus of the sheet sample in a certain direction is ; E the density of the sheet sample ; ρ the sound velocity ; C the propagation distance, that is, the transducer spacing ; L the propagation time ; T, then E = ρC ² = ρ (L/T) ² Then, if we measure the propagation time T over a certain distance L, assuming that ρ is constant within the range of the measurement sample, we get
Find E. If T is large, E is small.

By performing measurements while sequentially changing the angle between the sample and the sensor, a profile is obtained in which the measured values for the angles are compiled and organized. Therefore, the orientation of the sample strength, aspect ratio, etc. are required.

An example of the measurement values of a conventional sheet tester will be described. The transducer spacing L = 150 mm, a pair of ceramic piezoelectric elements were used as the transmitting transducer and the receiving transducer, ultrasonic waves of about 20 kHz were used, and a paper sheet of a certain composition was used as the sample. MD (machine
direction), the width direction of the paper sheet perpendicular to the MD
For a long sheet sample cut from the full width of a paper sheet in the CD (cross direction) direction,
After measuring and calculating T in each direction up to 170° at 10° intervals from the MD direction, the following table is printed out and a line diagram as shown in FIG. 4 is drawn. In addition, below
VALUE is the measured value in each angular direction with MD as 0°.

《 0° TO 80° 》 ANGLE= 0° VALUE=41.200μS ANGLE=10° VALUE=42.200μS ANGLE=20° VALUE=44.700μS ANGLE=30° VALUE=47.600μS ANGLE=40° VALUE=51.300μS ANGLE=50 ° VALUE=55.000μS ANGLE=60° VALUE=58.200μS ANGLE=70° VALUE=60.700μS ANGLE=80° VALUE=62.000μS 《90° TO 170°》 ANGLE= 90° VALUE=62.200μS ANGLE=100° VALUE= 60.900μS ANGLE=110° VALUE=58.600μS ANGLE=120° VALUE=55.400μS ANGLE=130° VALUE=51.800μS ANGLE=140° VALUE=48.000μS ANGLE=150° VALUE=44.900μS ANGLE=160° VALUE=42. 200μS ANGLE=170° VALUE=41.000μS DIRECTIONAL ANGLE (MD) = -4.66° ... (Orientation angle between MD and minimum value direction) DIRECTIONAL ANGLE (CD) = -4.36° ... (Orientation between CD and maximum value direction) CROSS−LENGTH RATIO (D:D) = 1.510 ... (ratio of measured values in CD direction and MD direction) PEAK (MD) = 40.922 μs ... (minimum value) PEAK (CD) = 62.207 μs ... (Maximum value) CROSS-LENGTH RATIO (P:P) = 1.520 ... (ratio between maximum value and minimum value) Therefore, the maximum intensity value is in the direction -4.66° from the MD direction and -4.36° from the CD direction This means that the minimum intensity value has been found. Conventionally, it took a long time to output the measurement results.

In the present invention, as shown in Figs. 1 and 2, a plurality of transducers 1, 1 are used as ultrasonic wave transmitting and ultrasonic wave receiving transducers, and each transducer 1, 1 has its center centered at O. They are provided protruding from the sensor surface 3 of the support plate 2 at predetermined center angle intervals (in the illustrated example, a total of 8 pieces, 4 pairs at 45° intervals) on the same circumference. Therefore, the distance between each vibrator 1, 1 is constant.

As _{shown in FIG .}
Let be R ₁ , R ₂ , R ₃ , and R ₄ . It is assumed that the transmitting transducer T ₁ also serves as the receiving transducer R ₅ .

If the diameter of the circumference is d, each vibrator T ₁
The distances between R ₁ , T ₂ R ₂ , T ₃ R ₃ , and T ₄ R ₄ are all d
It is.

In FIG. 1, the sensor body 4 is placed on a horizontal support plate 2.
The lower surface of the sensor surface 3 serves as a sensor surface 3, and is movable up and down in the direction perpendicular to the double arrow A. In addition, the sensor body 4 is indicated by the double arrow A.
A clamping device that can be raised and lowered in the directions is not shown.

A sheet sample support 5 is disposed below the support plate 2 and facing the sensor surface 3. The sheet sample support 5 ensures that the sensor body 4 descends and the vibrators 1, 1 come into contact with the elongated sheet sample 6 placed on the sheet sample support 5, and In order not to affect the measured values, it is desirable to use a flat plate body with elasticity and sound absorbing properties, such as a rubber sponge body. A sheet feeding device 7 is provided that can sequentially move the center of a desired point of the long sheet sample 6 on the sheet sample support 5 to just below the center O of the support plate 2. In the illustrated example, the sheet feeding device 7 is of a pinch roll type in which rolls are stacked vertically, and the rolls sandwich the sheet sample 6, and a computer device such as a CPU, which will be described later, moves the sheet sample 6 a predetermined distance along the arrows. It is possible to rotate and move in the B direction. The sheet sample 6 is introduced and guided by a guide roll 8. As mentioned above, the sheet sample 6 is held in contact with each vibrator 1, 1 of the sensor body 4 on the sheet sample support 5, but the clamping operation can also be performed by lifting and lowering only the sensor body 4. It may be done by raising and lowering only the body 5 or by raising and lowering both 4 and 5. The clamping device that clamps the sheet sample 6 is not shown as described above. As shown in Figure 3, the device is equipped with a computer device such as a CPU, and also includes a transmitter, a transmitting switching circuit, a transmitting oscillator, a receiving oscillator, a receiver, an amplifier, an output device, and a display. As shown in FIG. 5, the CPU is provided with output devices such as an ultrasonic transmitter operating means and transmitter transducers T ₁ , T ₂ , T ₃ , T _{4 .} . . switching operation means for a transmission switching circuit that sequentially switches and transmits signals;
The ultrasonic waves from the transmitting transducers T ₁ , T ₂ , T ₃ , T ₄ , etc. are received by any of the receiving transducers R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , etc. switching operation means of a wave reception switching circuit that causes waves, operation means of a receiver that receives the received ultrasonic waves from the receiver via an amplifier, and arithmetic analysis that calculates and analyzes the received measurement values as described later. Each means includes arithmetic analysis output means, sheet feeding device operating means, and clamping device operating means that sends the operation and measurement calculation results to a display device that is an output device or a separate output device, and performs output operations such as display, printout, etc. are provided, in response to operation signals of the clamping device operating means and the sheet feeding device operating means of the CPU, the clamping release operation of the clamping device, the sheet feeding operation to move the sheet sample 6 by a predetermined distance by the sheet feeding device 7, and the clamping device The clamping operation of the next position of the sheet sample 6 is performed by
After the clamping is completed, the same ultrasonic measurement and output operations as described above are repeated for the sheet sample 6 at a new measurement location.

As shown in FIGS. 2 and 3, between the transducers T ₁ R ₁ ,
Not limited to measurements in each direction between T ₂ R ₂ , T ₃ R ₃ , and T ₄ R ₄ , but also between T ₁ R ₂ , T ₂ R ₃ , T ₃ R ₄ , and T ₄ R ₅ . It is also possible to perform measurements in different directions. In this case, as shown in Figure 2, ∠R ₁ OR ₂ is an arc
Since the central angle of R ₁ R ₂ and ∠R ₁ T ₁ R ₂ are the same circumferential angle, ∠R ₁ T ₁ R ₂ = 1/2∠R ₁ OR ₂ , and the number of oscillators can be increased. Instead, the center angular spacing is halved, which means that twice as many different directions are measured in twice the number of transducers, and the measurement precision is doubled, making it possible to measure each measurement point in an extremely short time. It can be obtained in just a few seconds.

The distance between T ₁ R ₁ , etc. is equal to the circumferential diameter d, but the distance between T ₁ R ₂ , etc. is a constant distance shorter than the above d of dcos∠R ₁ T ₁ R ₂ ( In the illustrated example of FIG. 2, ∠R ₁ T ₁ R ₂ =22.5°), and the measurement result is converted into a distance d by the CPU. That is, the arithmetic analysis output means is configured to perform switching between a selected transmitting transducer and a receiving transducer at the same measurement point of the long sheet sample using received waves inputted from the receiver via an amplifier. The ultrasonic propagation time of the sample sheet is calculated sequentially into the propagation time over the same distance, and the calculated propagation time in all 360° directions at the same measurement point is calculated adjacently without changing the relative position between the sensor body and the sheet sample. The minimum and maximum values of the calculated propagation time group obtained by calculating twice the number of pairs of the plurality of pairs of transmitting and receiving transducers for each direction with an angular spacing of 1/2 of the center angular spacing of the transducers. , an orientation angle between the direction of the minimum value and the sheet manufacturing direction (MD), an orientation angle between the direction of the maximum value and a direction perpendicular to the MD (CD), a value of the ratio between the minimum value and the maximum value, and The value of the ratio between the propagation time value in the MD direction and the propagation time value in the CD direction is calculated for the same measurement point, and then the same calculation is performed sequentially for the calculated propagation time in each 360° direction for another measurement point, and each It is an arithmetic analysis output means that aggregates and organizes the arithmetic analysis of each calculated value at a measurement point as a profile and outputs it to the output device.

The number of the transducers 1 (T ₁ , T ₂ ..., R ₁ , R ₂ ...) can be increased as necessary, and the physical properties of the sheet sample in different directions can be measured by the increased number. Also, different directions can be obtained by different combinations _of transmitting transducers T _{1 ,} T _{2 .} . . and receiving transducers R ₁ , R ₂ . , it becomes possible to measure the physical properties of sheet samples at different positions, improving measurement accuracy.

Effects of the invention By arranging a large number of ultrasonic wave transmitting and receiving transducers on the same circumference on the sensor surface of the support plate of the sensor body, one end of a long sheet sample is cut out by the entire width of the wide sheet. By simply holding the sheet sample between the sheet feeding device and pressing the measurement start switch, there is no need to raise/lower or rotate the support plate etc. during measurement at a single measurement point, and the sheet sample can be moved without doubling the number of transducers. As mentioned above, two of the oscillator pairs
Double the number of physical property measurements and outputs in different measurement directions can be performed for each measurement point within a few seconds, and measurements at different measurement points of a long sheet sample as well as measurement value calculation and analysis can be performed automatically. Continuous measurement and analysis is now possible, making it possible to measure the physical properties of a large number of measurement points over the entire length of a long sheet sample from one end to the other in an extremely short time. It also enables automation of feedback such as changes in sheet manufacturing conditions to achieve uniformity, and has achieved the unique effect of obtaining profiles quickly and with high precision unparalleled by conventional methods.

[Brief explanation of drawings]

Fig. 1 is a schematic side view of the embodiment, Fig. 2 is a bottom view of the vibrator arrangement on the sensor surface, Fig. 3 is a circuit diagram of the operation system, Fig. 4 is an output example diagram, and Fig. 5 is a claim. It is a correspondence diagram. 1... Vibrator, 2... Support plate, 3... Sensor surface, 4... Sensor body, 5... Sheet sample support,
6... Sheet sample, 7... Sheet feeding device.

Claims (1)

[Scope of utility model registration request] In a sheet tester that uses an ultrasonic transmitting/receiving transducer to measure the propagation velocity of ultrasonic waves in a sheet sample between both the transmitting and receiving transducers, and to determine the physical properties of the sheet sample between the two transducers, an ultrasonic transmitter,
The transmitting switching circuit, the plurality of pairs of transmitting transducers and receiving transducers, the receiving switching circuit, the ultrasonic receiver, the amplifier, and the plurality of pairs of transmitting transducers and receiving transducers are the same. A sensor body protruding from the sensor surface of the support plate at predetermined central angular intervals on the circumference, a sheet sample support disposed facing the sensor surface, and a sensor body on the sheet sample support. a sheet feeding device that can move a long sheet sample a predetermined distance; a holding device that clamps and releases the sheet sample between the sensor body and the sheet sample support; an output device; the sheet feeding device actuating means for feeding the sheet sample by a predetermined distance in the longitudinal direction on the sheet sample support; A clamping device operating means, an operating means for the transmitter and the receiver, a switching means for the wave transmission switching circuit that sequentially switches and transmits the ultrasonic waves from the transmitter to an adjacent wave transmission transducer, and a transmission transducer; A switching means of a reception switching circuit that sequentially switches to a reception oscillator facing each other across the center of a circumference and a reception oscillator adjacent to the reception oscillator; The ultrasonic propagation time of the sample sheet between the selected transmitting transducer and the receiving transducer at the same measurement point of the long sheet sample is calculated sequentially into the propagation time for the same distance, and the sensor The calculated propagation time in all directions of 360° at the same measurement point is transmitted and received by the plurality of pairs in each direction at an angular interval of 1/2 of the center angular interval of adjacent vibrators, without changing the relative position between the body and the sheet sample. A number twice as many as the number of pairs of wave oscillators is calculated, and the minimum and maximum values of the calculated propagation time group obtained, the orientation angle between the direction of the minimum value and the sheet manufacturing direction (MD), and the maximum value direction and the orientation angle between the MD and the perpendicular direction (CD),
The value of the ratio between the minimum value and the maximum value and the value of the ratio of the propagation time value in the MD direction and the propagation time value in the CD direction are calculated for the same measurement point, and then for each other measurement point in all 360° directions. a computer device having respective means of an arithmetic analysis output means for sequentially performing similar arithmetic operations on the arithmetic propagation time of , and calculating and organizing the arithmetic analysis results as a profile of each calculated value at each measurement location and outputting the arithmetic analysis output means to the output device; An ultrasonic sheet tester characterized by: