JP2005265496A - Physical quantity measuring method and measuring instrument therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a physical quantity measuring method which enables the detection of a phase shift quantity accurately even if the transmission precision or the like of microwaves is not two high and capable of measuring the stable physical quantity of an object to be measured at low cost, and a measuring instrument therefor. <P>SOLUTION: In the physical quantity measuring method for detecting the phase shift quantity obtained by comparing the reference output of microwaves emitted from a microwave transmitter P and the output of the microwaves propagated through tea leaves and measuring the water content (physical quantity) of tea leaves on the basis of the phase shift quantity, the reference output is set to 360° being one cycle of the waveform corresponding to the cycle of its waveform and the waveform thereof is compared with the waveform corresponding to the waveform of the output propagated through the object to be measured to calculate phase shift quantity. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention detects a phase shift amount obtained by comparing a reference output of a microwave emitted from a microwave transmission means and an output of a microwave propagated through an object to be measured, and based on the phase shift amount The present invention relates to a physical quantity measuring method and a measuring apparatus for measuring the physical quantity of the object to be measured.

  Most of the tea leaf processing is a work process in which tea leaves are dried using a cocoon drying device (leaf punching machine, roughing machine, twisting machine, intermediate grinder, intermediate grinder, brewing machine, etc.). It is extremely important for quality control to grasp the dry state of tea leaves (water content of tea leaves) during the process. Therefore, various devices for measuring the moisture content of tea leaves have been proposed.

  For example, in the tea leaf moisture content measuring device disclosed in Patent Document 1, a microstrip line is arranged facing an accommodating space for accommodating a tea leaf being processed, and propagation of microwaves through the microstrip line is performed. Along with the path, the attenuation is obtained. That is, in the process of propagation of microwaves through the microstrip line, a part of it is absorbed and attenuated by the moisture contained in the tea leaves, so the attenuation and the moisture content contained in the tea leaves are correlated and oscillated. The moisture content can be calculated based on the attenuation amount of the microwave.

However, as a result of various studies to obtain the moisture content of the object to be measured such as tea leaves more accurately, the applicant of the present invention has found that the ratio of the attenuation amount to the “phase shift amount” which is another characteristic of the microstrip line. It has come to be noted that has a very high correlation with the moisture content in the measured object. That is, the phase shift amount and the attenuation amount obtained by comparing the reference output of the microwave emitted from the microstrip line with the output of the microwave propagated through the object to be measured are detected, and based on these parameters. The moisture content, which is the physical quantity of the object to be measured, is calculated.
JP 2000-46758 A

  However, in the physical quantity measuring method described above, a high-accuracy microwave transmitter such as a crystal oscillator is necessary to accurately detect the amount of phase shift due to microwaves, and therefore, an expensive apparatus is used. There is a problem that the measurement cost increases.

  The present invention has been made in view of such circumstances, and even if the microwave transmission accuracy is not so high, the amount of phase shift can be accurately detected, and a low-cost and stable object to be measured can be obtained. An object of the present invention is to provide a physical quantity measuring method and measuring apparatus capable of measuring a physical quantity.

  According to the first aspect of the present invention, the amount of phase shift obtained by comparing the reference output of the microwave emitted from the microwave transmission means and the output of the microwave propagated through the object to be measured is detected. In the physical quantity measurement method for measuring the physical quantity of the object to be measured based on the phase amount, the reference output is a natural number multiple of 360 degrees that is one period of the waveform corresponding to the period of the waveform. The amount of phase shift is obtained by comparing with the waveform corresponding to the waveform of the output propagated through.

  According to a second aspect of the present invention, in the physical quantity measuring method according to the first aspect, the moisture content of the object to be measured is calculated based on the phase shift amount and the attenuation amount of the microwave.

  According to a third aspect of the present invention, there is provided a microwave transmission means capable of transmitting a microwave, and a microwave reception means capable of receiving an output propagated through a measurement object in the microwave transmitted by the microwave transmission means. And a comparison operation means for detecting a phase shift amount by comparing the reference output of the microwave transmitted by the microwave transmission means and the output of the microwave received by the microwave reception means, In the physical quantity measuring device for measuring the physical quantity of the object to be measured based on the phase shift amount detected by the comparison calculation means, a natural number multiple of 360 degrees that is one period of the waveform corresponding to the period of the waveform of the reference output It is characterized by comprising conversion means for converting into

  According to a fourth aspect of the invention, there is provided the physical quantity measuring device according to the third aspect, further comprising attenuation amount detecting means for detecting an attenuation amount from the output received by the microwave receiving means, and the attenuation amount and the phase shift. The moisture content of the object to be measured is obtained based on the amount.

  According to the first and third aspects of the invention, even if the microwave transmission accuracy is not so high, the phase shift amount can be detected accurately, and the physical quantity of the measured object can be measured at low cost and stably. can do.

  According to the second and fourth aspects of the invention, the moisture content of the object to be measured can be measured at low cost and stably even if the microwave transmission accuracy is not so high.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
The physical quantity measuring device of the present embodiment is applied to a tea leaf moisture content measuring device, and the moisture content measuring device is disposed in a roughing machine 1 in a tea making process as shown in FIG. This is for measuring the moisture content of tea leaves during the drying process with the machine 1. The moisture content measuring device 2 disposed in the roughing machine 1 appropriately collects tea leaves during the drying process by the roughing machine 1, and calculates the moisture content by the detection means 15 and the calculation means 16 (see FIG. 4). Configured to get.

  In addition, you may comprise so that the moisture content of the tea leaf before a drying process or after a drying process may be measured. Further, reference numerals 8, 17, 18 and 19 in the same figure denote a control panel for controlling the roughing machine 1, a hot air generator for generating hot air, a hot air duct for introducing hot air, and a processed tea leaf, respectively. The take-out door is shown.

  As shown in FIG. 1, the moisture content measuring device 2 has a storage space S that can store tea leaves. The storage space S is vertically fixed by a fixed bottom plate 3 and an air cylinder 7. Surrounded by a measuring plate 4 that can be moved in the direction, a discharge plate 5 that can be moved in the left-right direction in the figure by an air cylinder 6, and a side plate (not shown) fixed to the front and back of the figure. Is formed.

  That is, the storage space S is a space surrounded by the bottom plate 3 on the lower side, the measurement plate 4 on the upper side, a pair of side plates on the side and the discharge plate 5 on the rear side, and the side facing the discharge plate 5 (front side) ) To form an opening A. The opening A is formed so as to face the processing chamber (chamber for drying the tea leaves) of the roughing machine 1, and the opening A allows the tea leaves being subjected to the drying process in the processing chamber to the accommodation space S. The tea leaves can be discharged from the accommodation space S after the introduction or moisture content measurement has been completed.

  The measurement plate 4 is composed of a plate-like member disposed above the bottom plate 3 by a predetermined distance, and can be moved toward or away from the bottom plate 3 by an air cylinder 7. That is, when the tea leaves are collected in the storage space S, the measurement plate 4 is positioned away from the bottom plate 3, and when measuring the moisture content, the measurement plate 4 is close to the bottom plate 3 as shown in FIG. Thus, the tea leaves in the accommodation space S can be pressurized. A shutter 9 is formed at the end (on the opening A side) of the measurement plate 4 so that the opening A can be opened and closed.

  Similarly to the bottom plate 3 and the measurement plate 4, the discharge plate 5 is composed of a plate-like member, and is configured to be able to slide in the gap between the measurement plate 4 and the bottom plate 3 by the air cylinder 6. That is, when the air cylinder 6 is driven from the state of FIG. 1, the discharge plate 5 enters the storage space S and the tea leaves in the storage space S can be discharged from the opening A as shown in FIG. It has become. In addition, you may make it provide wiping means, such as a scraper, in the lower end (side which contact | abuts the upper surface of the baseplate 3) of this discharge plate 5. FIG.

  The bottom plate 3 is formed of a plate-like member on which an upper surface faces the accommodation space S and is inclined at a predetermined angle, on which tea leaves introduced from the opening A can be placed. That is, since it is inclined downward by a predetermined angle from the opening A side to the discharge plate 5 side, it is avoided that the tea leaves in the accommodation space S naturally fall from the opening A. As shown in FIG. 2, a microstrip line 10 for measuring the moisture content of the tea leaves accommodated in the accommodation space S is formed on the upper surface of the bottom plate 3. Since the microstrip line 10 is formed along the edge of the bottom plate 3, it can measure almost the entire area of the accommodation space S.

  Further, as shown in FIG. 3, the microstrip line 10 is formed by stacking a protective plate 14, a strip conductor 11, a dielectric 12, and a conductor plate 13, and among these, between the strip conductor 11 and the conductor plate 13. In addition, an oscillator P that can oscillate microwaves is connected, and a receiver Q is connected to the other end to receive the oscillated microwaves. A protective plate 14 made of acrylic or the like is formed on the surface of the strip conductor 11 (that is, the side facing the accommodation space S).

  On the other hand, the strip conductor 11 and the conductor plate 13 are arranged to face each other with the dielectric 12 interposed therebetween. The strip conductor 11 and the conductor plate 13 are preferably made of metal such as copper or gold, and the dielectric 12 is preferably made of glass epoxy or ceramic. Further, the arrangement pattern in plan view of the strip conductor 11 (that is, the microstrip line 10) is not limited to that shown in FIG. 2, and may be formed in various patterns.

  Then, the microwave oscillated from the oscillator P causes various losses (conductor loss, dielectric loss and radiation loss) in the process of propagating through the microstrip line 10 and is received by the receiver Q after the level is lowered. Is done. Here, the microwave is transmitted from the oscillator P in a state where the tea leaves are not located on the microstrip line 10 and is received by the receiver Q. The transmission level (output level) of the oscillator P and the reception level of the receiver Q ( The difference from the input level is set as a reference value.

  On the other hand, when microwaves are sent out from the oscillator P in a state where tea leaves are introduced into the accommodation space S and the tea leaves are pressurized by bringing the measuring plate 4 close to the bottom plate 3, they are included in the tea leaves in addition to the above loss. Since a loss occurs due to the absorption of microwaves in the water that is absorbed, a value obtained by further subtracting the reference value from the difference between the transmission level and the reception level is the amount of attenuation of the microwaves due to the water in the tea leaves.

Specifically, when the attenuation amount of the microwave is ΔA, the attenuation amount ΔA is the moisture content M (%) of the tea leaf, the density ρ (kg / m ³ ) of the tea leaf accommodated in the accommodation space S, the tea leaf Can be expressed by functions G and Q of the length (effective measurement length) L (m) and the temperature T of tea leaves on the microstrip line. That is, the relational expression ΔA = G (M, ρ, L, T) = ρLG ′ (M, T) holds.

  The above relational expression is premised on the fact that the height of the tea leaves on the microstrip line 10 is sufficiently large and the change in the height does not affect the measured value. In particular, since it does not take much time for the measurement time, the premise is that the temperature T of the tea leaves is constant. Therefore, the relational expression can be simplified as ΔA = ρLG ″ (M) (hereinafter referred to as relational expression 1).

  However, in the moisture content measuring apparatus 2 according to the present embodiment, the moisture content is obtained by detecting the microwave phase shift amount Δφ in addition to the attenuation rate ΔA. Specifically, the oscillator P and the receiver Q are electrically connected to the detection means 15 for detecting the attenuation amount ΔA and the phase shift amount Δφ, and the attenuation amount ΔA detected by the detection means 15 and The calculating means 16 can calculate the ratio with the phase shift amount Δφ.

  The microwave phase shift amount Δφ can be expressed by the following equation under the same conditions as ΔA. In other words, the relational expression Δφ = Q (M, ρ, L, T) = ρLQ ′ (M, T) holds. For the same reason as described above, it is assumed that the temperature T of the tea leaves is constant. Therefore, the above relational expression can be simplified as Δφ = ρLQ ″ (M) (hereinafter referred to as relational expression 2).

  By the way, since the above-mentioned functions G ″ (M) and Q ″ (M) can be approximated as a linear function with respect to the moisture content M, the relational expression 1 and the relational expression 2 can be expressed as G ″ (M) = a1M + a2 respectively. , Q ″ (M) = b1M + b2. When the ratio of the attenuation amount to the phase shift amount is obtained using these, ΔA / Δφ = G ″ (M) / Q ″ (M) = (a1M + a2) / (b1M + b2) (hereinafter referred to as relational expression 3). .

  From the relational expression 3, it can be seen that the ratio ΔA / Δφ of the attenuation amount to the phase shift amount is a function of only the moisture content M, and the moisture content can be measured without being affected by the density ρ and the length L. Further, in a microwave of several GHz to measure a plant such as green tea, the attenuation amount with respect to the microwave can be regarded as almost zero in a dry state. Therefore, the relational expression 3 is further simplified. The following relational expression is obtained. That is, a relational expression 4 of ΔA / Δφ = a1 / b1 × (1-1 / (b1 / b2) M + b2) is derived, and the calculation means 16 obtains the moisture content M of the tea leaf using the relational expression 4.

  Here, in the moisture content measuring apparatus 2 according to the present embodiment, the detection means 15 has a circuit as a comparison calculation means as shown in FIG. 7 in order to detect the phase shift amount Δφ. The circuit includes a phase adjustment circuit 20 connected to the transmitter P, a conversion circuit 21 composed of a JK flip-flop as conversion means, an integration circuit 22 that forms a reference output α, and an RS connected to the receiver Q. A phase comparison circuit 23 composed of a flip-flop and an integration circuit 24 that forms a propagation output β are provided.

  The reference signal input from the transmitter P is detected by, for example, heterodyne detection, and then transmitted to the phase adjustment circuit 20. The phase adjustment circuit 20 performs zero point adjustment. As shown in FIG. 8, the waveform of the reference signal after the adjustment is a sine wave α1 having a half cycle of 180 degrees, but the conversion circuit 21 has one cycle of the waveform corresponding to the half cycle. It is converted into a certain 360-degree rectangular wave α2 (see FIG. 9), averaged by the integrating circuit 22 to become a DC voltage, and used as a reference output α.

  On the other hand, the propagation signal input from the receiver Q is detected by, for example, heterodyne detection (detected as a sine wave β1 in FIG. 8), and then transmitted to the phase comparison circuit 23. The phase comparison circuit 23 uses the phase adjustment circuit. Comparison with the reference signal adjusted at 20 is performed. As shown in FIG. 10, the signal output from the comparison circuit 23 becomes a rectangular wave β2 corresponding to the phase shift amount φ in FIG. 8, averaged by the integration circuit to become a DC voltage, and is set as a propagation output β. The

  Thereafter, the propagation means β through the integrating circuit 24 is compared with the reference output α through the integrating circuit 22 by the calculating means 16 to obtain the phase shift amount φ. As described above, in the process of obtaining the phase shift amount φ, the comparison with the output of the rectangular wave of 180 degrees is normally performed, whereas in the present embodiment, the rectangular wave of 360 degrees as shown in FIG. Since the comparison with the output is performed, even if the transmitter P, the heterodyne detector, the waveform shaper, etc. do not use a highly accurate one, the frequency fluctuation and waveform distortion can be absorbed, and a stable amount of phase shift is always achieved. Detection can be performed. That is, the accuracy of the transmitter P or the like is not so good. For example, the position of the zero point in FIG. 8 is shifted up and down or the waveform is shifted to the left and right due to noise, resulting in an asymmetric square. In addition, the phase shift amount φ can be reliably detected.

  The detection means 15 is formed with an attenuation detection means (not shown) electrically connected to the receiver Q, and the attenuation detected by the attenuation detection means (received by the receiver Q). In comparison with the phase shift amount φ detected as described above), the moisture content of the tea leaf is obtained. Therefore, since the phase shift amount φ is stably detected as described above, the moisture content of the tea leaf can also be detected stably.

Next, the effect | action in the moisture content measuring apparatus 2 of the said structure is demonstrated.
During the drying operation by the roughing machine 1, the shutter 9 is opened so that the opening A faces the processing chamber of the roughing machine 1. As a result, a part of the tea leaves sown upward by the drying operation of the roughing machine 1 enters from the opening A and is accommodated in the accommodation space S. When a predetermined amount of tea leaves are accommodated in the accommodation space S, the air cylinder 7 is driven to move the measuring plate 4 in the direction approaching the bottom plate 3, and the tea leaves in the accommodation space S as shown in FIG. Pressurize.

  In this state, a microwave is oscillated from the oscillator P and received by the receiver Q, and the detection unit 15 detects the attenuation amount ΔA and the phase shift amount φ. As described above, the phase shift amount φ detected here is obtained by comparing the reference output whose half cycle is 360 degrees with the output propagated through the tea leaves. Subsequently, the calculation means 16 calculates the ratio of the attenuation ΔA to the phase shift amount Δφ using the relational expression 4 (may be the relational expression 3), and calculates the moisture content M (%) from the ratio. Since the relational expression 4 used in the calculating unit 16 does not use the density ρ and the length L as parameters, the water content M (%) can be obtained without affecting the density ρ and the length L.

  That is, by determining the ratio of the attenuation amount to the phase shift amount, the parameters of density ρ and length L can be excluded from the relational expression for determining the moisture content M, which is an unstable factor of the measured value. It is not necessary to grasp the two parameters of the density ρ and the length L, and a high moisture content tea leaf can be accurately measured using a microstrip line.

  When the series of moisture content measurements described above is completed, the air cylinder 7 is driven and the measuring plate 4 returns to the original position (position shown in FIG. 1), the pressurizing action on the tea leaves is released, and the air cylinder 6 When driven, the discharge plate 5 slides into the accommodation space S (see FIG. 6). Thereby, the tea leaves in the accommodation space S are discharged from the opening A and returned to the processing chamber of the roughing machine 1. Thereafter, the air cylinder 6 is driven and the discharge plate 5 returns to the original position (position shown in FIG. 1), and is in a standby state until the next moisture content measurement.

  In this way, the discharge plate 5 can be slid in the storage space S, and the tea leaves in the storage space S can be returned to the processing chamber of the roughing machine 1, so that the tea leaves can be discharged from the storage space. Compared to what is performed, a series of operations in the moisture content measurement work can be performed automatically, and workability can be improved.

  Although the present embodiment has been described above, the present invention is not limited to this. For example, by connecting a plurality of JK flip-flops of the conversion circuit 21 in FIG. 7, the reference output corresponds to the period of the waveform. It is good also as a natural number multiple of 360 degree | times which is 1 period of the waveform to carry out. However, the natural number in this case does not include 0. Further, the present invention is not limited to the method for obtaining the moisture content of tea leaves by the ratio between the attenuation amount of microwaves and the amount of phase shift, but other calculation methods (for example, calculation methods using parameters such as density ρ and length L as in the past) ), The moisture content may be obtained from the attenuation amount of the microwave and the phase shift amount. That is, the reference output to be compared with the output propagated through the tea leaves (more specifically, the waveform corresponding to the waveform of the output propagated through the tea leaves) is calculated as the phase shift amount calculation method. It suffices to set 360 degrees, which is one period of the waveform corresponding to the period, and any subsequent calculation method may be used.

  Furthermore, in the present embodiment, the present invention is applied to a moisture content measuring device for measuring the moisture content of tea leaves, but may be applied to a device for obtaining the moisture content of an object to be measured other than tea leaves, and a physical quantity other than the moisture content. You may apply to what asks. In other words, the present invention can also be applied when obtaining some physical quantity of the object to be measured based on the phase shift amount of the microwave, thereby accurately shifting the phase shift amount even if the microwave transmission accuracy is not so high. Can be detected, and the physical quantity of the measured object can be measured at low cost and stably.

  If the reference output is a natural number multiple of 360 degrees, which is one period of the waveform corresponding to the period of the waveform, compared with the output propagated through the object to be measured and the amount of phase shift is required, the appearance The present invention can also be applied to ones having different shapes or to which other functions are added.

The longitudinal cross-sectional schematic diagram which shows the moisture content measuring apparatus which concerns on embodiment of this invention. Schematic diagram showing the microstrip line in the moisture content measuring apparatus Sectional view taken along line III-III in FIG. The block diagram which shows the connection relation of the transmitter in the same moisture content measuring apparatus, a receiver, a detection means, and a calculation means. FIG. 1 is a schematic diagram showing a state in which the measurement plate 4 is close to the bottom plate 3. 1 is a schematic diagram showing a state in which the discharge plate 5 has slid into the accommodation space S in FIG. The circuit diagram which shows the circuit for calculating | requiring the phase shift amount formed in the detection means in the moisture content measuring apparatus A sine wave indicating the reference output and propagation output input to the detection means in the moisture content measuring apparatus In the moisture content measuring device, a rectangular wave indicating a waveform corresponding to the period of the waveform of the reference output Rectangular wave output as propagation output in the moisture content measurement device Overall schematic diagram showing a roughing machine to which the moisture content measuring device is applied

Explanation of symbols

1 Coarse crusher 2 Moisture content measuring device (physical quantity measuring device)
DESCRIPTION OF SYMBOLS 3 Bottom plate 4 Measuring plate 5 Discharge plate 6, 7 Air cylinder 8 Control panel 9 Shutter 10 Microstrip line 11 Strip conductor 12 Dielectric 13 Conductor plate 14 Protection plate 15 Detection means 16 Calculation means 17 Hot air generator 18 Hot air duct 19 Take-out door 20 Phase adjustment circuit 21 Conversion circuit (conversion means)
22 Integration circuit 23 Phase comparison circuit 24 Integration circuit

Claims (4)

The amount of phase shift obtained by comparing the reference output of the microwave emitted from the microwave transmitting means and the output of the microwave propagated through the object to be measured is detected, and the object to be measured is detected based on the amount of phase shift. In a physical quantity measuring method for measuring physical quantities of things,
The reference output is compared with a waveform corresponding to the waveform of the output propagated through the object to be measured while being a natural number multiple of 360 degrees which is one period of the waveform corresponding to the period of the waveform, and the phase shift amount Is a physical quantity measurement method characterized by that.   2. The physical quantity measuring method according to claim 1, wherein the moisture content of the object to be measured is calculated based on the phase shift amount and the attenuation amount of the microwave. Microwave transmission means capable of transmitting microwaves;
Microwave receiving means capable of receiving the output propagated through the object to be measured in the microwave transmitted by the microwave transmitting means;
Comparison operation means for detecting a phase shift amount by comparing the reference output of the microwave transmitted by the microwave transmission means and the output of the microwave received by the microwave reception means,
In the physical quantity measuring apparatus for measuring the physical quantity of the object to be measured based on the phase shift amount detected by the comparison calculation means,
An apparatus for measuring a physical quantity, comprising conversion means for converting to a natural number multiple of 360 degrees, which is one period of a waveform corresponding to the period of the waveform of the reference output.   An attenuation amount detecting means for detecting an attenuation amount from an output received by the microwave receiving means is provided, and the moisture content of the object to be measured is obtained based on the attenuation amount and the phase shift amount. 3. The physical quantity measuring device according to 3.

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