CA1130380A - Apparatus for measuring a percentage of moisture and weighing of a sheet-like object - Google Patents
Apparatus for measuring a percentage of moisture and weighing of a sheet-like objectInfo
- Publication number
- CA1130380A CA1130380A CA338,832A CA338832A CA1130380A CA 1130380 A CA1130380 A CA 1130380A CA 338832 A CA338832 A CA 338832A CA 1130380 A CA1130380 A CA 1130380A
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- microwave
- signals
- sheet
- resonance
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Abstract
ABSTRACT OF THE DISCLOSURE
An apparatus for measuring the percentage of moisture content and weighing of a sheet-like object has a couple of metal box sections for providing a cavity with openings, which co-operatively form a cavity resonator, arranged facing at the openings to each other with a gap, interposed therebetween. In measurement, the sheet-like object is inserted in the gap. The percentage of moisture content of the sheet-like object is measured by detecting the variable resonant voltage of a microwave signal in-troduced into the cavity resonator. Weighing of the sheet-like object is measured detecting the variable resonant frequency of the microwave signal introduced.
An apparatus for measuring the percentage of moisture content and weighing of a sheet-like object has a couple of metal box sections for providing a cavity with openings, which co-operatively form a cavity resonator, arranged facing at the openings to each other with a gap, interposed therebetween. In measurement, the sheet-like object is inserted in the gap. The percentage of moisture content of the sheet-like object is measured by detecting the variable resonant voltage of a microwave signal in-troduced into the cavity resonator. Weighing of the sheet-like object is measured detecting the variable resonant frequency of the microwave signal introduced.
Description
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' The present invention relates to an apparatus for measuring moisture content of and weighing a sheet in which the sheet is inserted into a cavity resonator and its percentage moisture content is measured by detecting a variable and reduced resonant voltage of microwave intro-; duced into the cavity resonator. The weight of the sheet is measured be detecting a variable resonant frequency of the microwave introduced.
By convention, separate measuring systems are used for measuring moisture content (or a percentage moisturecontent) and weight per unit area (or weiqht) of sheets as references for indicating quality of the sheet. For example, ` to measure percentage moisture, infrared rays or microwaves are used to irradiate a sheet and the amount of the reduced wave is measured as electricity. To measure weight, rays or X rays are used to irradiate the sheet and the amount of ,` the rays transmitted through the object is measured as electricity.
As described above, the conventional measuring apparatus of this type needs two independ~nt measuring systems with different wave irradiating sources, so that the measuring apparatus is bulky and expensive. Because of the use of or X rays hazardous to a human body the conventional measuring apparatus also needs a protective device for protecting the human body. The use of two measuring systems further makes it difficult to measure a paper making process in on-line manner.
Thus the invention seeks to provide an apparatus for measuring moisture content and weight of a sheet with a microwave source commonly used for both measurements.
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According to the invention there is provided an apparatus for measuring the moisture content and weight of a sheet-like object comprising: (a) a single cavity resonator having a pair of metal box sections with openings arranged spaced from and facing each other thereby providing a gap therebetween for insertion of said sheet-like object, (b) means for generating microwave signals, (c) means for coupling said microwave signals to one of said metal box sections, (d) a microwave detector, (e) means for coupling microwave signals from the other of said metal box sections to the detector, said coupled microwave signals being attenuated and shifted in frequency at a resonance condition of said cavity resonsator when said sheet-like object is inserted within said gap, (f) said de-tector generating resonance signals upon detection of a resonance condition, and (g) circuit means connected to said detector for receiv-ing said resonance signals, said circuit means comprising:
(1) means for detecting the amount of attenuation of said resonance signals for substantially determining the moisture content of said sheet-like object, and (2) means for detec-ting the resonance frequency of said resonance signals for determining the weight of said sheet-like object.
With such an arrangement, a microwave generated from a microwave oscillator may be used as a common irra-diating source for both the measurements of moisture andweight of the sheet in the cavity resonator. Therefore, both the measurements may be made by an identical measuring system, without using rays or X rays hazardous -to a human body. Accordingly, the measuring apparatus may be made small. Further, such an arrangement enables a paper manu-facturing process to be measured in on-line manner.
.The invention will be better understood upon reading the following description in connection with the accompanying drawings, in which:
Figure 1 shows a perspective view of a cavity resonator according to the invention;
Figure 2 shows a block diagram of a measurement system according to the invention;
Figure 3 shows a block diagram of the system shown i~ Figure 2;
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Figure 4 shows a block diagram of another embodi-ment to be used in place of the measuring circuit and meters shown in Figure 2;
Figure 5 shows characteristic curves of resonant voltage values with respect to a resonant frequency when the :' moisture content of a sheet changes;
Figure 6 shows a characteristic curve of the resonant voltage with respect to the resonant frequency when the weight of an object to be measured within the cavity resonator changes under a fixed moisture content;
Figure 7, which is on the third sheet of the ;il drawings, shows characteristic curves of moisture content with respect to an amount of reduced microwave obtained by using a measuring apparatus according to the present inven-tion; and Figure 8 shows a characteristic curve of weight to resonant frequency with respect to weight measured ~y apparatus according to the invention.
Referring now to the drawings and particularly Figures 1 and 2, a cavity resonator 11 a~cording to the invention is comprised.of upper and lower metal box sections 12 and 13 for providing ~avities with openings 121 and 13 ~` arranged facing each other with gap 15 intervening. In > measurement, a sheet 14 to be measured is inserted into the 25 gap 15. A flange 122 provided~at the opening 121 oE the upper section 12 and a-.flange 132 provided at the openin~
131 of the lower section 13 are capacitively coupled with each other. One side of the upper section 12 is opened to have a coupling hole 123 coupled with a wave guide 16. A
microwave oscillator 17 such as a VCO (voltage controlled --3~
~L3~
oscillator) is mounted to the wave guide 16. The VCo 17 is connected to a saw-tooth wave oscillator 18 whereby a saw-tooth wave is applied to the oscillator 18 to oscillate a microwave signal which in turn is guided through the wave guide 16 to the cavity resonator 11. The lower section 13 is opened at one side to have a coupling hole 133 coupled with a wave guide 19. Within the wav~ guide 19, a device to detect a resonant output si~nal of the resonator 11, for example, a diode detector 20, is provided. An output signal from the detector 20 is applied -from a terminal a to a measuring circuit 21. The measuring circuit 21 receives the detected output from the detector 20 and produces at an output terminal _ a resonant voltage dependent on the sheet inserted into the gap-15 of the resonator 11. The resonant voltage is then applied to a meter 22 where it is visually indicated. The measuring circuit 21 also receives the saw-tooth wave signal from the saw tooth wave oscillator 18 -to produce a resonant frequency dependent on the sheet at an output terminal _. The resonant frequency is then applied to a meter 23 where it is visually indicated.
The de~ailed circuit diagram of the measuring circuit 21 will be descrihed with reference to Figure 3. The detected output signal from the detector 20 is fed in through the terminal a to an amplifier 31. The output signal of amplifier 31 is then applied to a known peak voltage hold circuit 32 which holds a peak value of the resonant voltage dependent on the sheet. The peak voltage is then compared with a reference voltage 34 in a differen-tial amplifier 33. The output signal from the differential amplifier 33 emerges at a terminal c. The output signal 1~3(.~
from the amplifier 31 is applied to a differentiationcircuit 35 where it is differentiated to produce a differen-tiated waveform signal which in turn is fed into a Schmidt trigger circuit 36. Upon.receipt of the dif~erential signal, the Sch~idt trigger circuit 36 procudes a rectangu-lar wave signal. A saw-tooth wave signal fed in through the terminal b is fed through an.amplifier 37 to a sample hold circuit 38. Upon receipt of the rectanyular wave signal derived from -the Schmidt trigger circuit 36, the sample hold circuit 38 sweeps the saw-tooth wave signal to produce an output signal proportional to the resonant frequency of the signal of those detec.ted output signals. The output signal from the sample hold circuit is applied through an amplifier 39 to an adder 40. A resonant voltage derived from the differential amplifier 33 also applied to adder 40 and compared with the output s.ignal proportional to the resonant : fre~uency to compensate for.deviation of the moisture content of the resonant frequency value at the resonant voltage. The compensated value emerges from a terminal d.
In place of~the measuring circuit 21 and the meters 22 and 23, an oscilloscope 41 may be used. In this case, the output signal from the detector 20 is applied as a vertical input signal to a terminal a of the oscilloscope 41. On the other hand, a saw-tooth wave signal ~rom the saw-tooth wave oscillator 18 is supplied as a horizontal input signal to a terminal b. As a result, a resonant curve dependent on the object to be measured is depicted on the display surface and from the curve depicted, the resonant voltage and the resonant frequency may be measured.
i 30 By using the above mentioned measuring circuit 21 ~13(~3~
~ or the oscilloscope 41, the sheet 14 is inserted into the : gap 15 of the cavity resonator 11 and the saw-tooth wave volta~e from the saw-tooth wave oscillator 18 is applied to the VCO 17. Upon application thereto of the saw-tooth wave, the VCO 17 produces a microwave signal frequency-modulated in accordance with the.level of the applied voltage which in turn is led to the cavity resonator 11 by way of the wave guide 16. When the oscillating frequency introduced approaches the resonant frequency of the cavity resonator 11, the detected output is guided out from the detector 20 through the wave guide 19.. In this case, if the sheet 1~ has a given weight, and the resonant voltage value and the reso-nant frequency.are L(V) and l~f/s), a resonant curve is depicted as indicated by curve I in Figure 5. As the moisture content of the object with the given weight in-creases, the reduction of the microwave increases t SO that the resonant voltage decreases from L(V) to L(M) and the resonant curve changes to become a curve II. When the moisture content further increases, the resonant voltage decreases from M(V) to N(~) and the resonant curve becomes a curve III.
The relationship between water content of the sheet or object to be~measured and the reduction of the microwave transmitted therethrouyh is as shown in Figure 6, 25 as a result of the measurementO As seen from the Figure, the reduction substantially linearly changes with increase of the moisture content. Therefore, by Measuring the resonant voltage by the measuring circuit 21 or the oscillo-scope 41 microwave and measuring the reduction of the microwave, a percentage of moisture content proportional to L3(~8(~
the reduction may be obtained.
When the sheet 14 contains water with a given percent of moisture, the resonant voltage is M(V) and the amount of a frequency deviation from the resonant frequency detected when no object is inserted in the gap of the cavity resonator is l(f/s), then the resonant curve obtained is depicted as curve I in Figure 7. When the weight of a sheet with given moisture content changes, the resonant frequency de~reases to be m~f/s~, ( m) and the resonant curve changes to become curve II. When ~he weight increases, a deviation of the resonant frequency decreases from m(f/s), to n(f/s), --and its resonant curve is depicted as curve III.
The experiment showed a relationship between the weiyht and the resonant frequency detected as shown in Figure 8. As shown, the~resonant fxequency substantially linearly changes as the weight increases. Accordingly, by measuring the deviation of the resonant frequency by the measuring circui-t 21 or the oscilloscope 41, a weight proportional to the-resonant frequency displacement may be obtained.
Having described a specific embodiment of the invention, it is obvious that modification and variation of the invention is possible in light of the above teachings.
' The present invention relates to an apparatus for measuring moisture content of and weighing a sheet in which the sheet is inserted into a cavity resonator and its percentage moisture content is measured by detecting a variable and reduced resonant voltage of microwave intro-; duced into the cavity resonator. The weight of the sheet is measured be detecting a variable resonant frequency of the microwave introduced.
By convention, separate measuring systems are used for measuring moisture content (or a percentage moisturecontent) and weight per unit area (or weiqht) of sheets as references for indicating quality of the sheet. For example, ` to measure percentage moisture, infrared rays or microwaves are used to irradiate a sheet and the amount of the reduced wave is measured as electricity. To measure weight, rays or X rays are used to irradiate the sheet and the amount of ,` the rays transmitted through the object is measured as electricity.
As described above, the conventional measuring apparatus of this type needs two independ~nt measuring systems with different wave irradiating sources, so that the measuring apparatus is bulky and expensive. Because of the use of or X rays hazardous to a human body the conventional measuring apparatus also needs a protective device for protecting the human body. The use of two measuring systems further makes it difficult to measure a paper making process in on-line manner.
Thus the invention seeks to provide an apparatus for measuring moisture content and weight of a sheet with a microwave source commonly used for both measurements.
,. ~
~3~
According to the invention there is provided an apparatus for measuring the moisture content and weight of a sheet-like object comprising: (a) a single cavity resonator having a pair of metal box sections with openings arranged spaced from and facing each other thereby providing a gap therebetween for insertion of said sheet-like object, (b) means for generating microwave signals, (c) means for coupling said microwave signals to one of said metal box sections, (d) a microwave detector, (e) means for coupling microwave signals from the other of said metal box sections to the detector, said coupled microwave signals being attenuated and shifted in frequency at a resonance condition of said cavity resonsator when said sheet-like object is inserted within said gap, (f) said de-tector generating resonance signals upon detection of a resonance condition, and (g) circuit means connected to said detector for receiv-ing said resonance signals, said circuit means comprising:
(1) means for detecting the amount of attenuation of said resonance signals for substantially determining the moisture content of said sheet-like object, and (2) means for detec-ting the resonance frequency of said resonance signals for determining the weight of said sheet-like object.
With such an arrangement, a microwave generated from a microwave oscillator may be used as a common irra-diating source for both the measurements of moisture andweight of the sheet in the cavity resonator. Therefore, both the measurements may be made by an identical measuring system, without using rays or X rays hazardous -to a human body. Accordingly, the measuring apparatus may be made small. Further, such an arrangement enables a paper manu-facturing process to be measured in on-line manner.
.The invention will be better understood upon reading the following description in connection with the accompanying drawings, in which:
Figure 1 shows a perspective view of a cavity resonator according to the invention;
Figure 2 shows a block diagram of a measurement system according to the invention;
Figure 3 shows a block diagram of the system shown i~ Figure 2;
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Figure 4 shows a block diagram of another embodi-ment to be used in place of the measuring circuit and meters shown in Figure 2;
Figure 5 shows characteristic curves of resonant voltage values with respect to a resonant frequency when the :' moisture content of a sheet changes;
Figure 6 shows a characteristic curve of the resonant voltage with respect to the resonant frequency when the weight of an object to be measured within the cavity resonator changes under a fixed moisture content;
Figure 7, which is on the third sheet of the ;il drawings, shows characteristic curves of moisture content with respect to an amount of reduced microwave obtained by using a measuring apparatus according to the present inven-tion; and Figure 8 shows a characteristic curve of weight to resonant frequency with respect to weight measured ~y apparatus according to the invention.
Referring now to the drawings and particularly Figures 1 and 2, a cavity resonator 11 a~cording to the invention is comprised.of upper and lower metal box sections 12 and 13 for providing ~avities with openings 121 and 13 ~` arranged facing each other with gap 15 intervening. In > measurement, a sheet 14 to be measured is inserted into the 25 gap 15. A flange 122 provided~at the opening 121 oE the upper section 12 and a-.flange 132 provided at the openin~
131 of the lower section 13 are capacitively coupled with each other. One side of the upper section 12 is opened to have a coupling hole 123 coupled with a wave guide 16. A
microwave oscillator 17 such as a VCO (voltage controlled --3~
~L3~
oscillator) is mounted to the wave guide 16. The VCo 17 is connected to a saw-tooth wave oscillator 18 whereby a saw-tooth wave is applied to the oscillator 18 to oscillate a microwave signal which in turn is guided through the wave guide 16 to the cavity resonator 11. The lower section 13 is opened at one side to have a coupling hole 133 coupled with a wave guide 19. Within the wav~ guide 19, a device to detect a resonant output si~nal of the resonator 11, for example, a diode detector 20, is provided. An output signal from the detector 20 is applied -from a terminal a to a measuring circuit 21. The measuring circuit 21 receives the detected output from the detector 20 and produces at an output terminal _ a resonant voltage dependent on the sheet inserted into the gap-15 of the resonator 11. The resonant voltage is then applied to a meter 22 where it is visually indicated. The measuring circuit 21 also receives the saw-tooth wave signal from the saw tooth wave oscillator 18 -to produce a resonant frequency dependent on the sheet at an output terminal _. The resonant frequency is then applied to a meter 23 where it is visually indicated.
The de~ailed circuit diagram of the measuring circuit 21 will be descrihed with reference to Figure 3. The detected output signal from the detector 20 is fed in through the terminal a to an amplifier 31. The output signal of amplifier 31 is then applied to a known peak voltage hold circuit 32 which holds a peak value of the resonant voltage dependent on the sheet. The peak voltage is then compared with a reference voltage 34 in a differen-tial amplifier 33. The output signal from the differential amplifier 33 emerges at a terminal c. The output signal 1~3(.~
from the amplifier 31 is applied to a differentiationcircuit 35 where it is differentiated to produce a differen-tiated waveform signal which in turn is fed into a Schmidt trigger circuit 36. Upon.receipt of the dif~erential signal, the Sch~idt trigger circuit 36 procudes a rectangu-lar wave signal. A saw-tooth wave signal fed in through the terminal b is fed through an.amplifier 37 to a sample hold circuit 38. Upon receipt of the rectanyular wave signal derived from -the Schmidt trigger circuit 36, the sample hold circuit 38 sweeps the saw-tooth wave signal to produce an output signal proportional to the resonant frequency of the signal of those detec.ted output signals. The output signal from the sample hold circuit is applied through an amplifier 39 to an adder 40. A resonant voltage derived from the differential amplifier 33 also applied to adder 40 and compared with the output s.ignal proportional to the resonant : fre~uency to compensate for.deviation of the moisture content of the resonant frequency value at the resonant voltage. The compensated value emerges from a terminal d.
In place of~the measuring circuit 21 and the meters 22 and 23, an oscilloscope 41 may be used. In this case, the output signal from the detector 20 is applied as a vertical input signal to a terminal a of the oscilloscope 41. On the other hand, a saw-tooth wave signal ~rom the saw-tooth wave oscillator 18 is supplied as a horizontal input signal to a terminal b. As a result, a resonant curve dependent on the object to be measured is depicted on the display surface and from the curve depicted, the resonant voltage and the resonant frequency may be measured.
i 30 By using the above mentioned measuring circuit 21 ~13(~3~
~ or the oscilloscope 41, the sheet 14 is inserted into the : gap 15 of the cavity resonator 11 and the saw-tooth wave volta~e from the saw-tooth wave oscillator 18 is applied to the VCO 17. Upon application thereto of the saw-tooth wave, the VCO 17 produces a microwave signal frequency-modulated in accordance with the.level of the applied voltage which in turn is led to the cavity resonator 11 by way of the wave guide 16. When the oscillating frequency introduced approaches the resonant frequency of the cavity resonator 11, the detected output is guided out from the detector 20 through the wave guide 19.. In this case, if the sheet 1~ has a given weight, and the resonant voltage value and the reso-nant frequency.are L(V) and l~f/s), a resonant curve is depicted as indicated by curve I in Figure 5. As the moisture content of the object with the given weight in-creases, the reduction of the microwave increases t SO that the resonant voltage decreases from L(V) to L(M) and the resonant curve changes to become a curve II. When the moisture content further increases, the resonant voltage decreases from M(V) to N(~) and the resonant curve becomes a curve III.
The relationship between water content of the sheet or object to be~measured and the reduction of the microwave transmitted therethrouyh is as shown in Figure 6, 25 as a result of the measurementO As seen from the Figure, the reduction substantially linearly changes with increase of the moisture content. Therefore, by Measuring the resonant voltage by the measuring circuit 21 or the oscillo-scope 41 microwave and measuring the reduction of the microwave, a percentage of moisture content proportional to L3(~8(~
the reduction may be obtained.
When the sheet 14 contains water with a given percent of moisture, the resonant voltage is M(V) and the amount of a frequency deviation from the resonant frequency detected when no object is inserted in the gap of the cavity resonator is l(f/s), then the resonant curve obtained is depicted as curve I in Figure 7. When the weight of a sheet with given moisture content changes, the resonant frequency de~reases to be m~f/s~, ( m) and the resonant curve changes to become curve II. When ~he weight increases, a deviation of the resonant frequency decreases from m(f/s), to n(f/s), --and its resonant curve is depicted as curve III.
The experiment showed a relationship between the weiyht and the resonant frequency detected as shown in Figure 8. As shown, the~resonant fxequency substantially linearly changes as the weight increases. Accordingly, by measuring the deviation of the resonant frequency by the measuring circui-t 21 or the oscilloscope 41, a weight proportional to the-resonant frequency displacement may be obtained.
Having described a specific embodiment of the invention, it is obvious that modification and variation of the invention is possible in light of the above teachings.
Claims (10)
1. Apparatus for measuring the moisture content and weight of a sheet-like object comprising:
(a) a single cavity resonator having a pair of metal box sections with openings arranged spaced from and facing each other thereby providing a gap therebetween for insertion of said sheet-like object, (b) means for generating microwave signals, (c) means for coupling said microwave signals to one of said metal box sections, (d) a microwave detector, (e) means for coupling microwave signals from the other of said metal box sections to the detector, said coupled microwave signals being attenuated and shifted in frequency at a resonance condition of said cavity resonator when said sheet-like object is inserted within said gap, (f) said detector generating resonance signals upon detection of a resonance condition, and (g) circuit means connected to said detector for receiving said resonance signals, said circuit means com-prising:
(1) means for detecting the amount of attenuation of said resonance signals for substantially determining the moisture content of said sheet-like object, and (2) means for detecting the resonance frequency of said resonance signals for determining the weight of said sheet like object.
(a) a single cavity resonator having a pair of metal box sections with openings arranged spaced from and facing each other thereby providing a gap therebetween for insertion of said sheet-like object, (b) means for generating microwave signals, (c) means for coupling said microwave signals to one of said metal box sections, (d) a microwave detector, (e) means for coupling microwave signals from the other of said metal box sections to the detector, said coupled microwave signals being attenuated and shifted in frequency at a resonance condition of said cavity resonator when said sheet-like object is inserted within said gap, (f) said detector generating resonance signals upon detection of a resonance condition, and (g) circuit means connected to said detector for receiving said resonance signals, said circuit means com-prising:
(1) means for detecting the amount of attenuation of said resonance signals for substantially determining the moisture content of said sheet-like object, and (2) means for detecting the resonance frequency of said resonance signals for determining the weight of said sheet like object.
2. Apparatus as recited in claim 1, wherein said means for coupling said microwave energy to said one of said metal box sections includes a first microwave guide means, said microwave generating means mounted to said first microwave guide means.
3. Apparatus as recited in claim 2, wherein said microwave generating means comprises a saw-tooth generator.
4. Apparatus as recited in claims 2 or 3, wherein said microwave generating means comprises a voltage controlled oscillator.
5. Apparatus as recited in claim 1, wherein said means for coupling microwave signals to said detector comprises a second microwave guide means, said detector mounted within said second microwave guide means.
6. Apparatus as recited in claim 5, wherein said detector comprises a diode detector.
7. Apparatus as recited in claim 1, wherein said means for detecting the amount of attenuation of said resonance signals comprises:
a peak voltage holding circuit for determining the peak voltage of said resonance signals, a reference voltage source for generating a reference voltage, and comparator means for comparing said peak voltage with said reference voltage, said comparator means providing an output signal indicative of moisture content, and said apparatus further comprising indication means responsive to said moisture content output signal for indicating same.
a peak voltage holding circuit for determining the peak voltage of said resonance signals, a reference voltage source for generating a reference voltage, and comparator means for comparing said peak voltage with said reference voltage, said comparator means providing an output signal indicative of moisture content, and said apparatus further comprising indication means responsive to said moisture content output signal for indicating same.
8. Apparatus as recited in claim 7, wherein said comparator means comprises a differential amplifier.
9. Apparatus as recited in claims 1 or 7, wherein said means for generating microwave signals com-prises a saw-tooth generator and voltage controlled oscilla-tor, and wherein said means for detecting the resonance frequency of said resonance signals comprises:
a differentiation circuit for receiving and differentiating said resonance signals, a sample and hold circuit connected to receive the output of said differentiation circuit, and an output of said saw-tooth generator, an amplifier connected to receive the output of said sample and hold circuit, an adder circuit connected to receive the output of said amplifier and said attenuating detecting means for adding same, and indicating means for indicating the resonance frequency of said resonance signals.
a differentiation circuit for receiving and differentiating said resonance signals, a sample and hold circuit connected to receive the output of said differentiation circuit, and an output of said saw-tooth generator, an amplifier connected to receive the output of said sample and hold circuit, an adder circuit connected to receive the output of said amplifier and said attenuating detecting means for adding same, and indicating means for indicating the resonance frequency of said resonance signals.
10. Apparatus as recited in claim 1, wherein said means for generating microwave signals comprises a saw-tooth generator and a voltage controlled oscillator, and said circuit means comprises an oscilliscope connected to receive said resonance signals as a vertical input thereto and connected to receive a saw-tooth voltage from said saw-tooth generator as a horizontal input thereto, whereby said oscilloscope displays a resonance curve of said attenuated, frequency-shifted resonance signals.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA338,832A CA1130380A (en) | 1979-10-31 | 1979-10-31 | Apparatus for measuring a percentage of moisture and weighing of a sheet-like object |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA338,832A CA1130380A (en) | 1979-10-31 | 1979-10-31 | Apparatus for measuring a percentage of moisture and weighing of a sheet-like object |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1130380A true CA1130380A (en) | 1982-08-24 |
Family
ID=4115490
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA338,832A Expired CA1130380A (en) | 1979-10-31 | 1979-10-31 | Apparatus for measuring a percentage of moisture and weighing of a sheet-like object |
Country Status (1)
| Country | Link |
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| CA (1) | CA1130380A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114235851A (en) * | 2021-11-08 | 2022-03-25 | 国网河北能源技术服务有限公司 | Microwave resonant cavity system for measuring steam humidity |
-
1979
- 1979-10-31 CA CA338,832A patent/CA1130380A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114235851A (en) * | 2021-11-08 | 2022-03-25 | 国网河北能源技术服务有限公司 | Microwave resonant cavity system for measuring steam humidity |
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