JP2001091321A - Flowrate sensor unit and flow meter using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flowrate sensor unit capable of reducing the generation of a flowrate measurement error based on the difference of individual sensor units. SOLUTION: A flowrate detector 5 including a heater and a temperature sensor is bonded to a heat transfer material 6, a fluid temperature detector 9 including a temperature sensor is contacted to a heat transfer material 10 and the flowrate detector 5, a fluid temperature detector 9 and parts of the heat transfer materials 6 and 10 are contained in a housing 2. In the housing 2, a memory 1 storing information on individual flowrate sensor units used for obtaining fluid flowrate by using the detection signal of a detection circuit comprising with the heater, the temperature sensor of the flowrate detector and the temperature sensor of the fluid temperature detector is contained. The flowrate detector 5, the fluid temperature detector 9 and the memory 1 are connected with a plurality of leads 4 in the housing 2. To the housing 2, a fluid flow path 13 is connected and the heat transfer material 6, 10 are extended into the flow path 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid flow detecting technology, and more particularly to a flow meter for measuring a flow rate or an integrated flow rate of a fluid flowing in a pipe, and a flow rate sensor unit used for the same.

[0002]

2. Description of the Related Art
Various types of flow sensors (or flow rate sensors) for measuring the flow rate (or flow rate) of various fluids, especially liquids, are used, but because of the ease of cost reduction, a so-called thermal type (or flow rate sensor) is used. In particular, indirect heat type) flow sensors are used.

In this indirectly heated flow sensor, a sensor chip formed by laminating a thin-film heating element and a thin-film temperature sensing element on a substrate by using a thin-film technology via an insulating layer is interposed between a fluid in a pipe and the sensor chip. What is arrange | positioned so that heat transfer is possible is used. By energizing the heating element, the temperature sensing element is heated to change the electrical characteristics of the temperature sensing element, for example, the value of electrical resistance.
This change in electric resistance (based on the temperature rise of the thermosensitive body)
Varies according to the flow rate (flow velocity) of the fluid flowing in the pipe. This is because a part of the calorific value of the heating element is transmitted into the fluid, and the amount of heat diffused into the fluid changes according to the flow rate (flow velocity) of the fluid. This is because the amount of heat supplied changes and the electrical resistance value of the thermosensitive body changes. The change in the electric resistance value of the temperature sensing element also differs depending on the temperature of the fluid. Therefore, a temperature sensing element for temperature compensation is incorporated in an electric circuit for measuring the change in the electric resistance value of the temperature sensing element. It has also been practiced to minimize the change in the flow measurement value due to the temperature of the fluid.

Such an indirectly heated flow sensor using a thin film element is disclosed in, for example, Japanese Patent Application Laid-Open No. 11-11856.
No. 6 describes this. In this flow sensor,
An electric circuit including a bridge circuit is used to obtain an electric output corresponding to the flow rate of the fluid.

By the way, the output of the electric circuit of this flow sensor is generally not in a simple proportional relationship with the flow value. Therefore, it is conceivable to perform data processing using a calibration curve in order to convert an electric circuit output into a flow value. A microcomputer can be used for this data processing, and the obtained flow rate digital signal can be input to a display device or, if desired, transmitted to a remote location via a communication line.

However, the flow sensor as described above is
In some applications, it is necessary to dispose (so-called disposable) a portion that comes into contact with a fluid and a portion around the fluid periodically or after a required amount of fluid flows. For example, when applied to the measurement of the flow rate of raw materials in the synthesis of high-purity reagents or the synthesis of pharmaceuticals, disposables are required to ensure that product purity does not decrease due to contamination with impurities. When applied to flow rate measurement of samples, disposable elements are required in order to prevent undesired chemical reactions from adversely affecting the analysis due to unknown components contained in the sample, When applied to the measurement of the flow rate of a medical solution to be injected into a living body or the flow rate of a biological fluid collected from a living body, disposable is required from the viewpoint of preventing disease infection.

[0007] In reality, there is a strong demand for downsizing and cost reduction of the disposable portion. Therefore, as this disposable part, it is conceivable to unitize a heat transfer member that can be extended into the fluid flow conduit, a sensor chip fixed to the heat transfer member, and wiring connected to terminals of the sensor chip. .

However, in such a case, there are the following problems. That is, when the sensor unit unitized as described above is used disposably,
In a data processing circuit for converting an electric circuit output into a flow value, a common calibration curve is used for a plurality of sensor units. This calibration curve defines a standard relationship, and does not take into account individual conditions for each sensor. However, in reality, each sensor unit is based on subtle differences in the position of the heat transfer member that can extend to the outside, the bonding state between the sensor chip and the heat transfer member, and the connection state between the sensor chip and the wiring. In many cases, the relationship between the output corresponding to the flow rate and the flow rate value differs for each sensor unit. In that case, a measurement error based on the individual difference of the sensor unit occurs in the flow rate measurement, and the measurement accuracy decreases.

Accordingly, an object of the present invention is to provide a flow sensor unit capable of reducing the occurrence of a flow measurement error based on individual differences between sensor units.

It is another object of the present invention to provide a flow meter capable of reducing the occurrence of flow measurement errors based on individual differences between sensor units.

[0011]

According to the present invention, as a means for achieving the above object, a flow rate detecting section including a heating element and a flow rate detecting temperature sensing element is joined to a flow rate detecting heat transfer member. A flow sensor unit in which the flow detection unit and a part of the flow detection heat transfer member are housed in a housing, wherein the housing includes the heating element and the flow detection temperature sensing element. A memory for storing the individual information of the flow rate sensor unit used when obtaining the fluid flow rate value using the detection signal of the detection circuit including the memory is housed, and the flow rate detection unit and the memory are outside the housing. A flow sensor unit, wherein the flow sensor unit is connected to the plurality of leads partially exposed to the inside of the housing.

In one embodiment of the present invention, a fluid temperature detecting portion including a fluid temperature detecting temperature sensing element is joined to a fluid temperature detecting heat transfer member, and the fluid temperature detecting portion and the fluid temperature detecting heat transfer member are connected to each other. A part of the transmission member is housed in the housing, the detection circuit includes the fluid temperature sensing temperature sensing element, and the fluid temperature sensing unit includes a plurality of leads partially exposed outside the housing. And in the housing.

In one aspect of the present invention, the individual information stored in the memory is correction information of a reference calibration curve used when obtaining a fluid flow value using a detection signal of the detection circuit.

In one embodiment of the present invention, a fluid flow passage is connected to the housing, and the other part of the heat transfer member for flow rate detection extends into the fluid flow passage.
In one aspect of the present invention, a fluid flow passage is connected to the housing, and the other part of the heat transfer member for detecting a fluid temperature extends into the fluid flow passage.

According to the present invention, a flow meter including the above-described flow sensor unit and an electric circuit connected to a lead of the flow sensor unit is provided to achieve the above object. The electric circuit unit obtains the fluid flow rate value by referring to a reference calibration curve stored in advance based on a detection signal of the detection circuit, and at that time, stores the fluid flow rate value in a memory in the flow rate sensor unit. A flow meter that corrects the reference calibration curve using the individual information.

In one embodiment of the present invention, the electric circuit section includes an analog circuit section that obtains an output corresponding to the flow rate of the fluid by using a detection signal of the detection circuit, and the electric circuit section based on an output of the analog circuit section. A digital circuit for obtaining a fluid flow value; the digital circuit includes a microcomputer and a main memory for storing the reference calibration curve;

In one embodiment of the present invention, the individual information stored in the memory of the flow rate sensor unit includes an output value corresponding to the fluid flow rate obtained by actually measuring the flow rate sensor unit and a true fluid flow rate. It reflects multiple relationships with values.

In one embodiment of the present invention, the lead of the flow rate sensor unit and the electric circuit are detachably connected.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view showing an embodiment of a flow sensor unit according to the present invention, and FIG.
It is A 'sectional drawing.

As shown in these figures, the flow rate detecting section 5 is joined to the surface of the fin plate 6 as a flow rate detecting heat transfer member, and the fluid temperature detecting section 9 is connected to the fluid temperature detecting heat transfer member. It is joined to the surface of the barrel fin plate 10. A part of the flow rate detecting unit 5, the fluid temperature detecting unit 9, and the fin plates 6, 10 are housed in the housing 2.

As shown in FIG. 3, the flow rate detector 5 has a thickness of, for example,
on a rectangular substrate 30 of about 2 mm square on the order of 2 mm, a thin film temperature sensing element 31 for flow rate detection, an interlayer insulating film 32, a thin film heating element 33, electrodes 34 and 35 for the heating element, and a protective film 36.
And a chip-shaped one in which a bonding layer of the thin film temperature sensing element 31 for flow rate detection and a pad layer 37 covering the heating element electrodes 34 and 35 are formed.

The thin film thermosensitive element 31 has a thickness of 0.5 to 0.5, for example.
It is patterned into a desired shape, for example, a meandering shape at about 1 μm.
Large temperature coefficient of platinum (Pt) and nickel (Ni)
A highly stable metal resistance film can be used. Or
Use manganese oxide type NTC thermistor
Can also be. The interlayer insulating film 32 and the protective film 36
For example, an SiO film having a thickness of about 1 μm_Two Using
Can be Examples of the thin film heating element 33 include a film
Resistors patterned to a desired shape with a thickness of about 1 μm
For example, Ni, Ni-Cr, Pt, and Ta-SiO
_Two , Nb-SiO _Two Use of cermet
Can be. The heating element electrodes 34 and 35 are, for example,
A film made of Ni having a film thickness of about 1 μm or
A stack of gold (Au) thin films of about 5 μm should be used.
Can be. As the pad layer 37, for example, the vertical and horizontal 0.
Au thin film of 2mm × 0.15mm and thickness of about 0.1μm
Alternatively, a film made of a Pt thin film can be used.

As shown in FIG. 4, the fluid temperature detecting section 9 has the same configuration as that in which the thin film heating element 33 and the like are removed from the flow rate detecting section 5, that is, a substrate 30 similar to the above-mentioned substrate 30. 'On the top, in order, the thin film temperature sensing element 31 for detecting fluid temperature
A thin film thermosensitive element 31 'for detecting fluid temperature and a protective film 36' similar to the protective film 36 described above are laminated, and a pad layer 37 'for covering the bonding portion of the thin film thermosensitive element 31' for detecting fluid temperature is formed. It is made of the formed chip.

One surface of one end of each of the fin plates 6 and 10 is connected to the substrates 30 and 3 of the flow rate detecting section 5 and the fluid temperature detecting section 9.
It is joined to the 0 'side by a joining material having good thermal conductivity. The fin plates 6 and 10 are made of, for example, copper, duralumin, or a copper-tungsten alloy and have a thickness of 0.1 mm.
A rectangular material having a width of about 2 mm and a width of about 2 mm can be used, and for example, a silver paste can be used as a bonding material.

As shown in FIGS. 1 and 2, a flow passage member 12 is connected to the housing 2 of the sensor unit, and the other ends of the fin plates 6 and 10 are connected to the flow passage member 12. It extends to a fluid flow passage 13 formed inside. The fin plates 6, 10 extend through the center of the fluid flow passage 13 having a substantially circular cross section. Fin plate 6,10
Are arranged along the flow direction of the fluid in the fluid flow passage 13 (indicated by an arrow in FIG. 1), so that the flow rate detecting unit 5 is not greatly affected by the fluid flow.
In addition, it is possible to satisfactorily transfer heat between the fluid temperature detection unit 9 and the fluid.

The housing 2 and the flow passage member 12 can be formed of a synthetic resin such as an epoxy resin or a polyphenylene sulfide resin. In the housing 2, a chip-shaped semiconductor memory 1 for storing individual information of the sensor unit is accommodated. This memory 1
Will be described later.

The electrode terminals (pads) of the flow rate detecting section 5, the fluid temperature detecting section 9 and the memory 1 are connected to the inner lead section (part in the housing) 4a of each lead 4 by the Au wire 3, respectively. Each lead 4 extends out of the housing 2 and is partially exposed outside the housing to form an outer lead portion 4b. The outer lead portion 4b may be, for example, a J-bend type.

In FIGS. 1 and 2, a space 15 is formed at the center of the housing 2 and the flow rate detecting portion 5 is provided here.
9, a part of the fin plates 6, 10 and the inner lead portion 4a are located.
2 is covered with a cover 16 that is integrated with the housing 2 as shown in FIG. 2, or is sealed with a synthetic resin so as to be integrated with the housing 2.

FIGS. 5 and 6 show modified examples of the flow sensor unit as described above. In these drawings, members and portions having the same functions as those in FIGS. 1 and 2 are denoted by the same reference numerals. This modification is different from that shown in FIGS. 1 and 2 only in that the housing 2 is formed integrally with the flow passage member 12 by simultaneous molding.

FIG. 7 shows a schematic configuration diagram of an embodiment of a flow meter constructed using the above-described flow sensor unit. A socket 20 is fitted to the outer lead portion 4b exposed outside the housing 2 of the sensor unit, and a wiring 21 is connected to the socket 20. One end of the wiring is electrically connected to each outer lead portion 4b, and the other end is connected to the electric circuit portion 22. The electric circuit section 22 has an analog circuit section 23, a digital circuit section 24, and a display section 25. The wiring 21 is connected to the analog circuit section 23, and the output of the analog circuit section 23 is a digital circuit. Input to the unit 24. The digital circuit unit 24 is connected to the display unit 25 and a communication line for communication with the outside.

FIG. 8 shows a modification of the connection between the flow sensor unit and the electric circuit unit as described above. In this modified example, a modular jack 26 is interposed in the middle of the wiring 21, and the modular jack 26 allows the wiring 21 to be connected to the sensor unit side portion 21 a and the electric circuit side portion 21 b.
And separable into Therefore, while maintaining the connection between the housing 2 and the socket 20, the modular jack 2
6, the wiring part 21b to the wiring part 21a, the socket 20
And the flow sensor unit attached to the socket can be removed. According to this, the wiring portion 21
a and the socket 20 can be disposable together with the flow sensor unit. Although the disposable part increases by doing in this way, the fin plates 6 and 10 like when attaching the housing 2 to the socket 20 are used.
Since there is no change in the state of extension to the fluid flow passage, there is an advantage that the attaching / detaching operation is facilitated.

FIG. 9 is a circuit diagram of the flowmeter as described above.

As a power supply, an AC 100 V is used.
Outputs 15V and + 5V DC. The DC +15 V output from the DC conversion circuit 71 is input to the voltage stabilization circuit 72.

The stabilized direct current supplied from the voltage stabilizing circuit 72 is supplied to a bridge circuit (detection circuit) 73.
The bridge circuit 73 includes a temperature sensing element 31 for flow rate detection, a temperature sensing element 31 ′ for temperature compensation, a resistor 74, and a variable resistor 75. Potentials Va and V at points a and b of the bridge circuit 73
b is input to the differential amplification circuit 76 having a variable amplification factor. The output of the differential amplifier circuit 76 is input to the integration circuit 77.

On the other hand, the output of the voltage stabilizing circuit 72 is supplied to the thin film heating element 33 via a field effect transistor 81 for controlling the current supplied to the thin film heating element 33. That is, in the flow rate detecting section 5, based on the heat generated by the thin-film heating element 33, the thin-film temperature sensing element 31 performs temperature sensing under the influence of heat absorption by the fluid to be detected via the fin plate 6. Then, as a result of the temperature sensitivity, FIG.
The difference between the potentials Va and Vb at points a and b of the bridge circuit 73 shown in FIG.

The value of (Va-Vb) changes when the temperature of the temperature sensing element 31 changes in accordance with the flow rate of the fluid. By appropriately setting the resistance value of the variable resistor 75 in advance, it is possible to obtain (Va−
The value of Vb) can be set to zero. At this reference flow rate, the output of the differential amplification circuit 76 is zero, and the integration circuit 77
Is constant (a value corresponding to the reference flow rate). The level of the output of the integrating circuit 77 is adjusted so that the minimum value is 0V.

The output of the integrating circuit 77 is a V / F conversion circuit 78
, Where a pulse signal having a frequency (for example, 5 × 10 ^{−5 at the} maximum) corresponding to the voltage signal is formed. This pulse signal has a constant pulse width (time width) (for example, 1 to 10).
Microseconds). For example, when the output of the integrating circuit 77 is 1 V, a pulse signal of a frequency of 0.5 kHz is output, and when the output of the integrating circuit 77 is 4 V, a pulse signal of a frequency of 2 kHz is output.

The output of the V / F conversion circuit 77 is supplied to the gate of the transistor 81. Thus, a current flows through the thin-film heating element 33 via the transistor 81 whose pulse signal has been input to the gate. Therefore, the divided voltage of the output voltage of the voltage stabilizing circuit 72 is applied to the thin film heating element 33 in a pulsed manner at a frequency corresponding to the output value of the integration circuit 77 via the transistor. Current flows intermittently. Thereby, the thin-film heating element 33 generates heat.
The frequency of the V / F conversion circuit 77 is
At 0, it is set based on a high-precision clock set based on the oscillation of the temperature-compensated crystal resonator 79.

The analog circuit section 23 includes the above components.

The pulse signal output from the V / F conversion circuit 77 is counted by a pulse counter 82. The microcomputer 83 converts the result into a corresponding flow rate (instantaneous flow rate) based on the pulse count (pulse frequency) based on the frequency generated by the reference frequency generation circuit 80, and integrates the flow rate with respect to time. Calculate the flow rate.

The conversion into the flow rate is performed using a reference calibration curve stored in the main memory 84 in advance. An example of this calibration curve is shown in FIG. That is, a data table obtained by measuring the pulse frequency output from the pulse counter 82 for each flow rate of the fluid using a certain flow rate sensor unit as a reference is stored in the main memory 84 as a reference calibration curve. ing.

In the present embodiment, the individual information of the sensor unit in the flow rate measurement is recorded in the memory 1 in the sensor unit. The individual information is, for example, data indicating a plurality of relationships between a true flow rate value measured and obtained in advance using the sensor unit and an output pulse frequency of the pulse counter 82.

The individual information will be described with reference to FIG. FIG. 11 shows a reference calibration curve SL. This reference calibration curve SL shows the relationship between the flow rate value x and the pulse frequency value y. On the other hand, the memory 1 in the sensor unit stores, as individual information, the relationship of (flow rate value-pulse frequency value) at points indicated by P and Q in FIG.
That is, P (x ₁ , y ₁ ) and Q (x ₂ , y ₂ ) are stored.

The data storage in the memory 1 is performed, for example, by using an EEPROM as the memory 1 in the presence of the space 15 as shown in FIGS. Before the application of (i), the output pulse frequency values y ₁ and y ₂ are measured by flowing the fluid at the flow rate values x ₁ and x ₂ , and these values are written by laser irradiation. After the storage of the individual information in the memory 1, the resin sealing of the space 15 or the provision of the cover 16 is performed.
Complete the sensor unit. Thereby, the memory 1
Can be manufactured at low cost. The memory 1 is not limited to the EEPROM,
A different type of writable memory may be used.

When measuring the flow rate of the fluid to be detected, the microcomputer 83 first corrects the reference calibration curve based on the individual information as described above to create a corrected calibration curve. That is, the reference calibration curve SL as shown in FIG.
Based on (x ₁ , y ₁ ) and Q (x ₂ , y ₂ ), (x ₁
, Y ₁ ) and (x ₂ , y ₂ ) are obtained. Specifically [including the sign, for example, the correction value to the flow rate value x when the pulse frequency value is y ₁ C (y
₁ ) is added to the value [x + C (y ₁ )]. When the pulse frequency value is y ₂ , a correction value [including the sign] C (y ₂ ) is added to the flow rate value x [x + C]. (Y ₂ )], and for other pulse frequency values y, the correction value C (y) may be determined by, for example, an extrapolation method. At that time,
In consideration of the function form of y = f (x) of the reference calibration curve SL, extrapolation is performed so that the deviation from this form is reduced.

In the above description, the individual information is P (x ₁ ,
Although the case where two points of y ₁ ) and Q (x ₂ , y ₂ ) are shown, the correction calibration curve CL can be more easily obtained by using three or more pieces of individual information.

As described above, the microcomputer 83 specifies the flow rate value on the correction calibration curve CL corresponding to the pulse frequency output from the pulse counter 82 at the time of the flow rate measurement as the measured value (as described above). Alternatively, the reference flow rate value may be obtained by using the reference calibration curve SL, and the correction value C (y) may be added thereto.

The digital circuit section 30 includes the above components.

The values of the instantaneous flow rate and the integrated flow rate obtained as described above are displayed on the display unit 25 and are transmitted to the outside via a telephone line or other communication line including a network. If desired, data of the instantaneous flow rate and the integrated flow rate can be stored in the main memory 84.

Reference numeral 85 denotes a backup power supply (for example, a battery).

When the fluid flow rate increases or decreases, the differential amplifier circuit 76
Changes in polarity (depending on the positive or negative of the resistance-temperature characteristic of the flow sensing temperature sensor 31) and magnitude according to the value of (Va-Vb), and the output of the integration circuit 77 changes accordingly. I do. The speed of change of the output of the integrating circuit 77 can be adjusted by setting the amplification factor of the differential amplifier circuit 76. The response characteristics of the control system are set by the integrating circuit 77 and the differential amplifier circuit 76.

When the fluid flow rate increases, the temperature of the flow rate detecting temperature sensing element 31 decreases. Therefore, the integration circuit 77 for increasing the amount of heat generated by the thin film heating element 33 (ie, increasing the pulse frequency). Output (higher voltage value)
When the output of the integrating circuit reaches a voltage corresponding to the fluid flow rate, the bridge circuit 73 is in an equilibrium state.

On the other hand, when the flow rate of the fluid decreases, the temperature of the temperature sensing element 31 rises, so that the thin-film heating element 3
An output (lower voltage value) of the integrating circuit 77 that reduces the amount of heat generated in (3) (that is, reduces the pulse frequency) is obtained. When the output of the integrating circuit reaches a voltage corresponding to the fluid flow rate, the bridge The circuit 73 is in an equilibrium state.

That is, in the control system of the present embodiment, the frequency (corresponding to the amount of heat) of the pulsed current supplied to the thin film heating element 33 is set so that the bridge circuit 73 is in an equilibrium state. The realization of the state (response of the control system) can be, for example, within 0.1 seconds.

In the embodiment described above, since the reference calibration curve is corrected based on the individual information of the newly used flow rate sensor unit, the tip of the flow rate detector 5 and the fluid temperature detector 9 and the heat transfer member are corrected. Even if the connection state with the flow sensor unit or the connection state of the wire bonding between the chip of the flow rate detection unit 5 and the fluid temperature detection unit 9 and the lead differs depending on the individual flow rate sensor unit, the flow rate can be controlled with high accuracy by the individual flow rate sensor unit. A measurement can be made. Therefore, even when the electric circuit portion of the flowmeter is continuously used and the flow sensor unit is disposable, high measurement accuracy can be maintained, and the applicable field of flow measurement can be expanded.

According to the above embodiment, the pulse signal generated by the V / F conversion circuit 78 is used for measuring the flow rate, and this pulse signal can sufficiently reduce an error due to a temperature change. Since it is easy, it is possible to reduce the error between the flow rate value and the integrated flow rate value obtained based on the pulse frequency. Further, in the present embodiment, since the energization of the thin-film heating element 33 is controlled by ON / OFF using a pulse signal generated by the V / F conversion circuit 78, the occurrence of a control error based on a temperature change is extremely small. .

Further, in this embodiment, since the flow rate detecting section is a minute chip including a thin film heating element and a thin film temperature sensing element, the above-described high-speed response is realized.
The accuracy of the flow measurement can be improved.

In the present embodiment, the temperature of the flow detecting temperature sensing element 31 around the thin film heating element 33 is maintained substantially constant regardless of the flow rate of the fluid to be detected. It is possible to prevent the occurrence of ignition explosion of the flammable fluid to be detected with little deterioration over time.

[0060]

As described above, according to the flow rate sensor unit and the flow meter of the present invention, the connection state of the chip of the flow rate detecting section and the fluid temperature detecting section with the heat transfer member and the lead, etc., are individual flow rate sensors. Even if the flow sensor unit differs, the flow rate measurement can be performed with high accuracy by the flow rate sensor unit, and the high measurement accuracy can be maintained even when the flow rate sensor unit is used disposably.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a flow sensor unit of the present invention.

FIG. 2 is a sectional view taken along line A-A 'of FIG.

FIG. 3 is an exploded perspective view illustrating a configuration of a flow detection unit.

FIG. 4 is an exploded perspective view illustrating a configuration of a fluid temperature detection unit.

FIG. 5 is a schematic sectional view showing a flow sensor unit of the present invention.

FIG. 6 is a sectional view taken along line A-A ′ of FIG. 5;

FIG. 7 is a schematic configuration diagram of a flow meter of the present invention.

FIG. 8 is a diagram showing a connection example between a flow sensor unit and an electric circuit unit of the flow meter of the present invention.

FIG. 9 is a circuit configuration diagram of the flow meter of the present invention.

FIG. 10 is a diagram showing an example of a calibration curve in the flow meter of the present invention.

FIG. 11 is a diagram showing a reference calibration curve and a correction calibration curve in the flow meter of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Memory in sensor unit 2 Housing 3 Bonding wire 4 Lead 4a Inner lead part 4b Outer lead part 5 Flow rate detecting part 6 Fin plate 9 Fluid temperature detecting part 10 Fin plate 12 Flow passage member 13 Fluid flow passage 15 Space 16 Cover 20 Socket 21 Wiring 22 Electric circuit part 23 Analog circuit part 24 Digital circuit part 25 Display part 26 Modular jack 30 Substrate 31 Thin film temperature sensing element for flow rate detection 32 Interlayer insulating film 33 Thin film heating element 34, 35 Heating element electrode 36 Protective film 37 Pad layer 30 'Substrate 31' Thin-film thermosensitive element for detecting fluid temperature 36 'Protective film 37' Pad layer 71 DC conversion circuit 72 Voltage stabilization circuit 73 Bridge circuit (detection circuit) 74 Resistor 75 Variable resistor 76 Differential amplifier 77 Integration Circuit 78 V / F Conversion circuit 79 Temperature-compensated crystal oscillator 80 Reference frequency generation circuit 81 Field effect transistor 82 Pulse counter 83 Microcomputer 84 Main memory 85 Backup power supply SL Reference calibration curve CL Correction calibration curve C (y) Correction value

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takayuki Takahata 1333-2, Hara-shi, Ageo-shi, Saitama Mitsui Mining & Smelting Co., Ltd. F-term (reference) 2F030 CA10 CD04 CE02 CE03 CE04 CE09 CE24 CE25 2F035 EA04 EA08 EA09

Claims (9)

[Claims] 1. A flow rate detection unit including a heating element and a flow rate detection temperature sensing element is joined to a flow rate detection heat transfer member, and the flow rate detection unit and a part of the flow rate detection heat transfer member are connected to each other. A flow rate sensor unit housed in a housing, wherein the flow rate sensor unit is used to obtain a fluid flow rate value using a detection signal of a detection circuit including the heating element and the flow rate detection temperature sensing element in the housing. A memory for storing individual information of the flow sensor unit is stored, and the flow detection unit and the memory are connected in the housing with a plurality of leads partially exposed outside the housing. Characteristic flow sensor unit. 2. A fluid temperature detecting portion including a fluid temperature detecting temperature sensing element is joined to a fluid temperature detecting heat transfer member, and the fluid temperature detecting portion and a part of the fluid temperature detecting heat transfer member are connected to each other. The sensing circuit is housed in the housing, the sensing circuit includes the fluid temperature sensing temperature sensing element, and the fluid temperature sensing unit is connected in the housing to a plurality of leads partially exposed outside the housing. The flow sensor unit according to claim 1, wherein 3. The method according to claim 2, wherein the individual information stored in the memory is correction information of a reference calibration curve used when obtaining a fluid flow value using a detection signal of the detection circuit. Item 3. A flow sensor unit according to any one of Items 1 to 2. 4. The fluid flow passage is connected to the housing, and another portion of the flow rate detecting heat transfer member extends into the fluid flow passage.
The flow sensor unit according to any one of claims 1 to 3. 5. The fluid flow passage is connected to the housing, and another portion of the heat transfer member for detecting fluid temperature extends into the fluid flow passage. The flow sensor unit according to any one of claims 1 to 4. 6. A flowmeter comprising: the flow sensor unit according to claim 1; and an electric circuit connected to a lead of the flow sensor unit.
The electric circuit unit is based on a detection signal of the detection circuit,
The fluid flow rate value is obtained by referring to a reference calibration curve stored in advance, and at this time, the reference calibration curve is corrected using individual information stored in a memory in the flow rate sensor unit. A flow meter, characterized in that: 7. The analog circuit section for obtaining an output corresponding to the flow rate of the fluid using a detection signal of the detection circuit, and a digital circuit for obtaining the fluid flow rate value based on the output of the analog circuit section. The flow meter according to claim 6, further comprising a circuit section, wherein the digital circuit section includes a microcomputer and a main memory for storing the reference calibration curve. 8. The individual information stored in the memory of the flow rate sensor unit includes a plurality of relationships between an output value corresponding to the fluid flow rate obtained by actually measuring the flow rate sensor unit and a true fluid flow rate value. 8. The flowmeter according to claim 7, wherein the flowmeter is reflected. 9. The flow meter according to claim 6, wherein a lead of the flow sensor unit and the electric circuit unit are detachably connected.