JP4052149B2 - Temperature measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a temperature measuring device that measures the temperature of a fluid using an ultrasonic flow meter, and is suitable for an automatic supply device for effervescent drinking water, and particularly for controlling the amount of gas injected into drinking water. The present invention relates to a temperature measuring device suitable for water temperature measurement.
[0002]
[Prior art]
In an effervescent beverage supply device, for example, a beer dispenser, the temperature of beer is measured by inserting a temperature sensor into a beer supply conduit in order to suppress the amount of foaming due to temperature change, and the amount of beer supplied Is measured by a flow rate detection means (not shown). As a temperature measuring device for such a beer dispenser, for example, the temperature measuring device shown in FIG. 7 includes a temperature sensor 11 inserted into a beer conduit 9 and a converter 1.
[0003]
The converter 1 includes a temperature measurement unit 12 that measures the temperature of beer based on a signal from the temperature sensor 15, and a control unit that controls the amount of carbon dioxide injected into the beer based on the temperature signal from the temperature measurement unit 12. 13.
[0004]
The temperature sensor 15 detects the temperature of the beer in the conduit 9 and outputs an electrical signal corresponding to the temperature to the temperature measuring unit 12, and various types are known (see, for example, Patent Documents 1 to 3). .) The temperature measurement unit 12 converts the electrical signal input from the temperature sensor 15 into a temperature signal and outputs the temperature signal to the control unit 13.
[0005]
When the relationship between the beer temperature and the carbon dioxide content is stored in advance and the temperature signal is input, the control unit 13 can read the carbon dioxide content corresponding to the input temperature. Therefore, the control unit 13 is set to output a pressure adjustment signal to the pressure adjustment valve of the carbon dioxide gas cylinder so that the content of carbon dioxide gas corresponds to the temperature of beer.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-023373 [Patent Document 2]
Japanese Patent Laid-Open No. 11-326070 [Patent Document 3]
Japanese Patent Laid-Open No. 2000-292269
[Problems to be solved by the invention]
By the way, in the effervescent beverage supply apparatus, for example, the beer dispenser, as described above, the pressure control of the carbon dioxide gas is performed through the control unit 13 from the measured beer temperature in order to suppress the foaming amount due to the temperature change. For the purpose of quantitative extraction, separate measuring means, temperature measuring means and flow rate detecting means, were provided. As described above, the apparatus for measuring the temperature and flow rate of the fluid uses two types of measuring means, which causes problems that the size is increased and the price is increased.
[0008]
The present invention has been made in view of the above, and an object of the present invention is to provide a temperature measuring device capable of measuring the temperature of a fluid while reducing the size and reducing the cost and reducing the cost.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a temperature measuring device according to claim 1 is a temperature measuring device for measuring a temperature of a fluid passing through a conduit, and a pair of ultrasonic waves disposed on an outer peripheral portion of the conduit. The temperature of the conduit is measured based on a signal output from the transmitter / receiver and the temperature sensor, and the propagation time and speed of the ultrasonic wave propagating in the conduit, and the ultrasonic wave propagating in the fluid are measured. A calculation unit that calculates a propagation time and a sound velocity, and transmits ultrasonic waves bidirectionally between the pair of ultrasonic transmitters and receivers, and receives the signals from each other, and the calculation unit propagates the received upstream signal. Calculate the total propagation time from the arithmetic average of the time and the propagation time in the downstream direction, and calculate the propagation time of the fluid only from the total propagation time based on the sound velocity specified from the measured temperature of the conduit. Of only the fluid And identifies the temperature of the fluid by calculating the sound speed of the fluid from between.
[0010]
According to a second aspect of the present invention, there is provided the temperature measuring device according to the above invention, wherein the temperature sensor is embedded in a conduit.
[0011]
According to a third aspect of the present invention, there is provided the temperature measuring device according to the above invention, wherein a plurality of the temperature sensors are embedded in the conduit.
[0012]
According to a fourth aspect of the present invention, there is provided the temperature measuring device according to the above invention, wherein the temperature sensor is disposed in the conduit along the flow of the fluid.
[0013]
According to a fifth aspect of the present invention, there is provided the temperature measuring device according to the above invention, wherein the calculation unit calculates the temperature of the fluid based on signals output from the plurality of temperature sensors.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a temperature measuring device according to the present invention will be described below with reference to the drawings. In addition, this invention is not limited by this embodiment.
[0015]
In order to achieve the above object, a temperature measuring device according to the present invention is characterized in that the temperature of a fluid can be measured at a low cost with a simple configuration by using an ultrasonic flowmeter. Further, the present invention is based on the principle that the temperature of the fluid is derived from the sound speed of the fluid by utilizing the fact that the temperature of the fluid has a correlation with the sound speed of the fluid.
[0016]
First, the measurement principle of the ultrasonic flowmeter will be described. An ultrasonic flowmeter using ultrasonic waves transmits and receives ultrasonic waves to and from each other using a pair of ultrasonic transmitters / receivers arranged in a conduit that allows a fluid to be measured to pass through. Then, utilizing the fact that the ultrasonic velocity in the moving fluid becomes the vector sum of the sound velocity and the flow velocity, the ultrasonic wave is emitted in the flow direction and in the opposite direction, and the flow rate is obtained by the propagation time difference, the signal phase difference, etc. .
[0017]
Therefore, since the temperature measuring device according to the present invention also has a function as an ultrasonic flow meter, the basic configuration is also common to the ultrasonic flow meter.
[0018]
FIG. 1 is a block diagram showing a configuration of a temperature measuring apparatus according to Embodiment 1 of the present invention. In FIG. 1, this temperature measuring device is disposed on the outer periphery of a conduit 9 through which a fluid passes, and includes a pair of ultrasonic transmitters / receivers 10a and 10b that transmit and receive ultrasonic waves to each other, and ultrasonic transmitters / receivers 10a and 10b. And a converter 1 that processes an input ultrasonic signal, identifies a temperature of the fluid, and outputs a control signal for controlling the amount of gas contained in the fluid.
[0019]
First, when receiving a transmission instruction of an ultrasonic signal from the control unit 8, the transmission unit 2 transmits an ultrasonic transmission signal to the ultrasonic transceiver 10 a via the switch 7. Here, the switch 7 switches the signal from the transmitter 2 to the ultrasonic transmitters / receivers 10a and 10b and the signal from the ultrasonic transmitter / receivers 10a and 10b to the receiver 3 under the control of the controller 8. .
[0020]
When an ultrasonic transmission signal is transmitted from the transmitter 2 to the ultrasonic transceiver 10a, ultrasonic waves are transmitted from the ultrasonic transceiver 10a and received by the ultrasonic transceiver 10b. Then, an ultrasonic reception signal based on the ultrasonic wave received from the ultrasonic transmitter / receiver 10 b is transmitted to the receiving unit 3 via the switch 7.
[0021]
The receiving unit 3 binarizes the received ultrasonic signal based on a predetermined reference value set in advance, recognizes it as a received signal, and transmits the time recognized as received to the time measuring unit 4. The time measurement unit 4 is notified from the control unit 8 of the time at which the ultrasonic signal is transmitted, and measures the time difference between the transmission signal and the reception signal to thereby transmit the ultrasonic signal from the ultrasonic transmitter / receiver 10a to the ultrasonic transmitter / receiver 10b. Identify the propagation time. Similarly, by switching the transmission path of the switch 7, the time measuring unit 4 specifies the propagation time from the ultrasonic transmitter / receiver 10 b to the ultrasonic transmitter / receiver 10 a, and calculates these two types of propagation times to the calculation unit. 6 to send.
[0022]
The calculation unit 6 stores the relationship between the temperature of the conduit 9 and the speed of sound and the relationship between the temperature of the fluid and the speed of sound, and the detection signals from the temperature sensors 11 to 13 as temperature signals. And a temperature measuring unit 5b for conversion. Further, the temperature sensors 11 to 13 are disposed in the conduit 9 along the flow of the fluid, detect the temperature of the conduit 9, and output a detection signal to the temperature measuring unit 5 b via the converter 1. The temperature measurement unit 5b calculates the temperature of the conduit 9 based on the input detection signal and outputs a temperature signal corresponding to the temperature to the calculation unit 6.
[0023]
The calculation unit 6 calculates the sound velocity in the fluid from the temperature of the conduit 9 input from the temperature measurement unit 5b and the difference between the propagation times of the two types of ultrasonic waves propagated in the fluid input from the time measurement unit 4. calculate. Then, the fluid temperature is specified by the relational characteristic between the fluid temperature and the sound speed stored in the storage unit 5a.
[0024]
Here, a method for specifying the temperature of the fluid flowing through the conduit 9 based on the propagation time of two types of ultrasonic waves will be described in detail. FIG. 2 is a time chart showing changes in the transmission signal (a) in the transmission unit 2, the reception signal (b) in the reception unit 3, and the time measurement unit transmission pulse (c) in the time measurement unit 4. FIG. 3 is a cross-sectional view of the conduit 9 for explaining the ultrasonic propagation path in detail.
[0025]
First, when an instruction for transmitting an ultrasonic wave is output from the control unit 8, the transmission unit 2 outputs an ultrasonic transmission signal a1 as shown in FIG. An ultrasonic wave is transmitted from the ultrasonic transmitter / receiver 10 a disposed in the conduit 9 by the ultrasonic transmission signal a <b> 1 of the transmitter 2. Originating ultrasonic wave, via conduit 9 route R _A, as shown in FIG. 3, once enters the fluid at a predetermined refraction angle, via the fluid path R _B, is reflected by the conduit 9, the fluid It again enters the conduit 9 through the path R _B ′ with a predetermined refraction angle, and reaches the ultrasonic transceiver 10 b via the conduit 9 path R _A ′. Since the ultrasonic signal passing through such a path (R _A → R _B → R _B ′ → R _A ′) is the shortest path through the fluid, the receiving unit 3 is shown in FIG. A received signal b2 as shown is received.
[0026]
By the way, a part of the transmitted ultrasonic wave propagates only through the conduit 9 and reaches the ultrasonic transceiver 10b. Since the sound wave passing through only the conduit 9 is shorter than the path passing through both the conduit 9 and the fluid, it can reach the ultrasonic transceiver 10b quickly. Moreover, the sound velocity of the ultrasonic wave propagating through the polysulfone material known as the material of the conduit 9 is 2,300 m / s at 3 MHz and 10 ° C., while the ultrasonic wave propagating through water, which is the main component of the fluid. The speed of sound is 1,400 m / s at 3 MHz and 10 ° C. Therefore, the ultrasonic wave that travels only through the conduit 9 propagates the fastest.
[0027]
However, since the ultrasonic wave is attenuated by various factors such as the density, viscosity, specific heat, and thermal conductivity of the medium, the attenuation rate of the ultrasonic wave does not depend only on the path length. Therefore, as shown in FIG. 2B, the sound wave b1 passing only through the conduit 9 is fast, but the amplitude is received with a small amplitude, and conversely, the sound wave b2 passing through both the conduit 9 and the fluid is slow, but the amplitude is Received greatly.
[0028]
In the case of the temperature measuring device according to the present invention, the above is true, and in the receiving unit 3, the received signal b1 is an ultrasonic wave propagated only through the conduit 9, and b2 is both the conduit 9 and the fluid. It is the ultrasonic wave that propagated. Therefore, if a predetermined reference value is set, it is possible to distinguish the reception signal of the ultrasonic wave b1 propagated only through the conduit 9 and the ultrasonic wave b2 propagated through both the conduit 9 and the fluid.
[0029]
When a predetermined reference value is set in the receiving unit 3 as described above, the output b becomes zero because b1 of the reception signals b1 and b2 received by the receiving unit 3 does not satisfy the reference value. In the time measuring unit 4, pulses c1 and c2 corresponding to the transmission signal a1 and the reception signal b2 are transmitted.
[0030]
Next, a case where ultrasonic waves are transmitted from the ultrasonic transmitter / receiver 10b downstream of the fluid and received by the ultrasonic transmitter / receiver 10a upstream of the fluid will be described.
[0031]
In this case, the transmission unit 2 transmits a transmission signal a2 as shown in FIG. 2A, and the reception unit 3 receives reception signals b3 and b4 as shown in FIG. 2B. Also in this case, for the same reason as described above, the ultrasonic wave propagated only through the conduit 9 is received as the received signal b3, and the ultrasonic wave propagated through both the conduit 9 and the fluid is received as the received signal b4.
[0032]
Here, if a predetermined reference value is set, only the received signal b 4 having a large amplitude can be output to the time measuring unit 4. The time measuring unit 4 transmits pulses c3 and c4 as shown in FIG. 2 (c) corresponding to the transmission signal a2 transmitted by the transmission unit 2 and the reception signal b4 received by the reception unit 3, and the calculation unit 5 is output.
[0033]
Here, assuming that the propagation time of the ultrasonic wave from the upstream to the downstream of the fluid is T _1a and the propagation time from the downstream to the upstream is T _1b , T _1a = c 2 -c 1, T _1b = c 4 -c 3. Under the influence of the fluid flow, T _1a ≠ T _1b .
[0034]
However, if the total propagation time through both the conduit 9 and the stationary fluid is T ₂ , if the fluid flow in the conduit 9 is constant, the downstream propagation time T _1a and the upstream propagation time T Using the arithmetic mean of _1b , the total propagation time T ₂ can be expressed as in the following formula (1).
T ₂ = (T _1a + T _1b ) / 2 (1)
[0035]
Here, the total propagation time T ₂ passing through both static fluid conduit 9 is obtained, the total propagation time T _2, as can be seen from FIG. 4 showing a relationship between characteristics of the temperature of the fluid, the total propagation time T ₂ is a two-linear function of temperature, from the total propagation time T _2, the temperature of the uniquely fluid can not be specified. This is because the sound speed varies depending on the medium. In other words, the speed of sound depends on the medium.
[0036]
Therefore, the total propagation time T ₂ when the fluid passes through the conduit 9 needs to be divided into the propagation time of the conduit 9 and the propagation time of the fluid. Therefore, the total propagation time T _2, 'the time T _A to propagate, fluid path (R _B ← → R _B conduit 9 path _{(R A ← → R A)} ' when divided into a time T _B to propagate) The total propagation time T ₂ is expressed by the following equation (2).
T ₂ = T _A + T _B (2)
Further, assuming that the sound speed of the conduit 9 is V _A and the sound speed of the fluid is V _B , the propagation times T _A and T _B are expressed by the following equations (3) and (4).
T _A = (R _A + R _A ′) / V _A (3)
T _B = (R _B + R _B ′) / V _B (4)
[0037]
By the way, in the temperature measurement part 5b, the detection signal output from the temperature sensors 11-13 embedded in the conduit | pipe 9 is converted into a temperature signal, and is output to the calculating part 6. FIG. As shown in FIG. 3, if the three temperature sensors 11 to 13 are installed in the conduit 9 so as to follow the flow of the fluid, they are output from the temperature sensors 11 to 13 and converted into temperature signals by the temperature measuring unit 5b. For each of the temperature signals t11, t12, and t13, the calculation unit 6 can calculate the temperature t of the conduit 9 by defining it as an arithmetic mean value {(t11 + t12 + t13) / 3}.
[0038]
On the other hand, the storage unit 5a in the calculation unit 6 stores a relational characteristic (FIG. 5) between the temperature t of the conduit 9 and the sound velocity. When the temperature t of the conduit 9 is specified, the sound velocity V of the conduit 9 is determined. _A is specified. When the acoustic velocity V _A of the conduit 9 is specified, the conduit 9 path (R _A + R _A ') is geometrically derived, ultrasonic wave propagation time T _A of the calculation propagating conduit 9 from equation (3) Is done.
[0039]
When the propagation time T _A of the conduit 9 is calculated, the propagation time T _{B of the} ultrasonic wave of the fluid is calculated from the equation (2). Further, when the fluid propagation time T _B is calculated, the fluid path (R _B + R _B ′) is geometrically derived, so the sound velocity V _{B of the} fluid is calculated from Equation (4).
[0040]
Therefore, if the relationship characteristic (FIG. 6) between the sound speed of the fluid and the temperature of the fluid is input to the storage unit 5a, if the value of the sound speed V _B of the fluid calculated by the calculation unit 6 is known, the relationship characteristic ( The temperature of the fluid is specified from FIG. When the temperature of the fluid is specified, the calculation unit 6 outputs the specified fluid temperature to the control unit 8. The control unit 8 stores the carbon dioxide content at the specified fluid temperature, and controls the pressure adjustment to the pressure adjustment valve of the gas cylinder so that the value of the content matches a predetermined value. A signal is output and a beverage containing a predetermined amount of carbon dioxide gas is supplied.
[0041]
In the description of the embodiment, the number of the temperature sensors 11 to 13 installed in the conduit 9 is three, but the number may be other than three. This is because it is appropriate to select an appropriate number of the temperature sensors 11 to 13 according to the length and shape of the conduit 9 and the flow rate of the fluid.
[0042]
In the description of the embodiment, the temperature sensors 11 to 13 installed in the conduit 9 are arranged along the fluid flow direction, but the temperature sensors 11 to 13 may be arranged in the direction perpendicular to the fluid flow. Good. This is because the temperature distribution in the thickness direction of the conduit 9 can be taken into account when specifying the temperature of the conduit 9.
[0043]
【The invention's effect】
As described above, according to the present invention, since the temperature of the fluid can be measured using the existing ultrasonic flowmeter, without providing additional parts or the like for the purpose of fluid temperature measurement, That is, there is an effect that the temperature of the fluid can be measured in a compact manner without increasing the cost.
[0044]
Further, according to the present invention, since it is not necessary to add parts to the conduit 9 for fluid temperature measurement, gas is vaporized by protrusions such as sensors for temperature measurement, and ultrasonic waves generated by bubbles are used. Error of the propagation time is caused, and an adverse effect on the ultrasonic flowmeter and the temperature measuring device according to the present invention can be eliminated.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an ultrasonic fluid temperature measuring apparatus according to an embodiment of the present invention.
FIG. 2 is a time chart showing changes in signals in a transmission unit, a reception unit, and a time measurement unit of the ultrasonic fluid temperature measurement apparatus described in the embodiment of the present invention.
3 is a cross-sectional view of a conduit for explaining an ultrasonic wave propagation path in the conduit of the temperature measuring device shown in FIG.
FIG. 4 is a graph showing the relationship between the total propagation time of the ultrasonic wave passing through the conduit and the fluid and the temperature of the fluid described in the embodiment of the present invention.
FIG. 5 is a graph showing a relational characteristic between the sound velocity of the conduit and the temperature stored in the storage unit of the ultrasonic fluid temperature measuring apparatus according to the present invention.
FIG. 6 is a graph showing a relational characteristic between the sound speed and the temperature of the fluid stored in the storage unit of the ultrasonic fluid temperature measuring apparatus according to the present invention.
FIG. 7 is a block diagram showing a configuration of a conventional fluid temperature measuring device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Converter 2 Transmission part 3 Reception part 4 Time measurement part 5a Memory | storage part 5b Temperature measurement part 6 Calculation part 7 Switch 8 Control part 9 Conduit 10a Ultrasonic transmitter / receiver 10b Ultrasonic transmitter / receiver 11 Temperature sensor 12 Temperature sensor 13 Temperature sensor 14 Temperature measurement part 15 Temperature sensor 16 Control part

Claims (5)

A temperature measuring device for measuring the temperature of a fluid passing through a conduit, a pair of ultrasonic transceivers and a temperature sensor disposed on an outer periphery of the conduit;
The temperature of the conduit is measured based on a signal output from the temperature sensor, and the propagation time and sound velocity of the ultrasonic wave propagating through the conduit and the propagation time and sound velocity of the ultrasonic wave propagating through the fluid are calculated. With an arithmetic unit,
The ultrasonic wave is propagated bidirectionally between the pair of ultrasonic transmitters / receivers and received by each other, and the arithmetic unit calculates an arithmetic average of the received propagation time in the upstream direction and propagation time in the downstream direction. The total propagation time is calculated from the measured temperature of the conduit, and the propagation time of only the fluid is calculated from the total propagation time based on the sound speed specified from the measured conduit temperature, and the sound speed of the fluid is calculated from the calculated propagation time of only the fluid. The temperature measuring device characterized by specifying the temperature of the fluid.   The temperature measuring device according to claim 1, wherein the temperature sensor is embedded in a conduit.   The temperature measuring device according to claim 1, wherein a plurality of the temperature sensors are embedded in the conduit.   The temperature measuring device according to claim 3, wherein the temperature sensor is disposed in the conduit along the flow of the fluid.   The temperature measuring device according to claim 3 or 4, wherein the calculation unit calculates the temperature of the fluid based on signals output from the plurality of temperature sensors.

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