KR200290516Y1 - Heater-inserted-typed flow metering apparatus - Google Patents

Abstract

The thermal insertion type flow measuring apparatus of the present invention includes a DC power supply 21 which receives an input voltage and supplies first and second constant voltages V1 and V2 and an operating voltage V3; At least one fluid temperature sensing unit (22, 22 ') having at least one sensor each sensing a fluid temperature with a first constant voltage (V1); A voltage selector 24 which selects one of the first and second constant voltages V1 and V2 according to the control signal Co from the CPU and outputs the selected voltage Vs; At least one loss calorie sensing unit 25, 25 ′ having at least one sensor each sensing a loss of calorie with the selected voltage Vs from the voltage selector 24; A voltage fluctuation measuring unit 23 measuring voltage fluctuations based on the first and second constant voltages V1 and V2; And a CPU 6 for controlling the DC power supply 21, the fluid temperature sensing units 22 and 22 ′, the voltage selecting unit 24, the lossy heat sensing units 25 and 25 ′ and the voltage fluctuation measuring unit 23. ); In this case, the fluid temperature sensing unit (22, 22 ') and the loss calorie sensing unit (25, 25'), the sensor having a standard resistance (Rs) and the temperature dynamic resistance characteristics with a low temperature dynamic resistance and A / D It consists of transducers 22a and 22b.

Description

Thermal Insertion Flow Measurement Device {HEATER-INSERTED-TYPED FLOW METERING APPARATUS}

The present invention relates to a thermally insertable flow measuring device and method for detecting and measuring the amount of fluid flowing in a conduit by a hot wire electronic circuit. The present invention relates to an intelligent thermally inserting flow measuring device capable of precise flow measurement and easy control. .

The thermal flow meter is a flow meter that calculates a flow rate by calculating a loss heat amount according to a flow of a fluid, and calculates a flow rate based on the flow rate. An intelligent thermal flow meter is a fluid type selection information based on fluid-related information such as sensor length, fluid diameter, improved accuracy due to power fluctuations, and the influence of changes in average amount depending on the sensor tooth method, and flow rate from the sensed voltage, current and power. It is a sensor type flowmeter that can measure and measure average flow velocity and fluid temperature.

Generally, the thermal mass flowmeter which belongs to a mass flowmeter as a thermal flowmeter has a bypass heating type, a direct pipe heating type, and an insertion type according to a measuring method.

Among them, there is a conventional hot wire insertion type flow meter such as Korean Patent No. 166087. As shown in FIG. 1, it is possible to omit the dedicated air passage of the hot air flow meter, and to provide a miniaturized, space-saving and low-cost hot air flow meter, and to achieve the above object, The air flow meter is inserted into the existing air passage, and the circuit module and the sub air passage are integrally formed and the connector part is inserted so as to be located outside the main air passage.

1 and 2 is a device equipped with the conventional thermal air flow meter to the main body forming the main air passage, Figure 1 is an external view of a conventional thermal insertion type air flow measuring device, Figure 2 is AA of Figure 1 It is a cross section.

In more detail, the sub air passage 3 in which the heating wire 6 and the thermosensitive resistor 7 are disposed has a flat housing having a flat housing in the flow direction of air holding the circuit board 5. It is inserted into the main body 11 which is integrally formed in 1) and constitutes the main air passage 4, and is fixed by the fixing screw 10. At this time, the connector 2 integrally formed in the module housing 1 is located outside the main body 11.

The main body 11 is arranged in the intake system layer of the internal combustion engine so that the entire flow rate of the intake air 12 passes through the main air passage 4 of the main body 11, and the total flow rate is controlled by the classified air to the secondary air passage. To detect. The circuit board 5 is a circuit for heating the heating wire 6 or processing a signal from the thermosensitive resistor 7, but may have various other correction functions.

Thus, the module housing 1 is inserted to be perpendicular to the air flow from the flat mounting hole in the flow direction of air installed in the main body 11, and then fixed to the main body with screws 10. In this case, it is a part of the connector 2 that goes out of the main body 11. The reference numbers 8 and 9 are terminals, respectively.

Therefore, the air sucked into the internal combustion engine flows through the air passage 4 of the main body 11, but a part of the air flows through the air passage 3, and the flow rate is measured in the heating wire 6 installed on the way. In addition, since the module housing 1 is cooled by the intake air amount, the flow rate is calculated from the heat loss of the sensor.

However, in the conventional flow meter, the flow rate is measured by a loss of heat according to the flow rate by passing a constant current to the thermocouple in a current control circuit by being attached to a part of the pipe, and then measuring a separate fluid pipe diameter or setting the structure of the fluid pipe. By measuring the flow rate, it is difficult to calculate the precise flow rate due to the fluctuating static flow rate, the change in the dynamic resistance of the thermocouple, the change in the resistance of the thermocouple, the Lenolz according to the tooth position, and the change in the number of external surface design. Since measurement errors occur depending on the shape of the fluid pipe (curved pipe, straight pipe, etc.), there is a problem when the mounting method is changed to an ideal fluid state of 20D or more.

In other words, if the flow rate is an ideal fluid, it is relatively accurate, but may vary depending on the position at which the flow meter is mounted. That is, the flow rate through the conduit is the fastest in the center of the conduit and slows toward the edge, and also increases in the downward direction under the influence of gravity. In other words, the measurement at any one position in the conduit becomes too large.

In addition, the conventional method has no countermeasures against drift and vortex generation, and the error is too severe.

In addition, in the conventional thermal insertion type flow measurement method, the flow rate is measured by supplying a constant current source, but the supply of the constant current source is more complicated than the supply of the constant voltage source.

The present invention is intended to solve the above problems, the object of the present invention is to measure the flow rate in the entire position, not one position in the conduit, it is possible to make a precise measurement, relatively accurate in the occurrence of drift and vortex The present invention provides a thermally insertable flow measuring apparatus and method capable of measuring the same.

Another object of the present invention is to provide a flow meter that can be measured by the supply of a constant voltage source.

Further objects or effects of the present invention will become more apparent from the following detailed description of the invention described with reference to the accompanying drawings.

1 is an external view of a conventional thermal insertion type air flow measurement device.

2 is a sectional view taken along the line A-A in FIG.

3 is a block diagram of a thermal insertion type flow measurement device according to the present invention.

4 is a circuit diagram of the voltage selector of FIG. 3.

5 is a detailed view of the fluid temperature sensing unit of FIG. 3.

6 is an example of a method of inserting a sensor into a fluid tube.

7 is another example of placing a sensor in a fluid tube.

8 is a circuit diagram for explaining a relationship between an applied voltage and a measurement voltage of each sensor.

<Description of the symbols for the main parts of the drawings>

1: Module housing 2: Connector

3: secondary air passage 4: main air passage

5: circuit board 6: heating wire

7: thermosensitive resistor 8, 9: terminal

10: screw 11: body

21: DC power supply 22, 22 ': fluid temperature sensing unit

23: voltage fluctuation measuring unit 24: voltage selector

25, 25 ': heat loss sensing unit 26: CPU

27: flow rate display portion 28: flow rate display portion

29: fluid temperature display unit 30: fluid selection unit

31: Communication port

The present invention relates to an intelligent thermal insertion type flow measurement method and apparatus for precisely measuring the flow rate of a gas or liquid flowing in a pipe, and utilizes the temperature change of the temperature sensor and the heat loss of the sensor according to the flow rate of the gas. , The main principle to measure the flow rate, the sub principle of varying the measured quantity difference according to the location and mounting method of the sensor, and the A / D calculation of the current and voltage measured in the temperature and loss calorie sensor The sub principle of knowing resistance, dynamic resistance, sensor length and diameter of fluid flow pipe, the intrinsic value of viscosity, specific heat, etc. related to fluid, and the flow rate of fluid from the equation By applying the principle of minutes that can be calculated and the sub-principles of knowing the characteristic values of a sensor, the microprocessor can calculate and measure the flow rate and flow rate. Provide the device.

That is, the thermal insertion type flow measuring device according to an aspect of the present invention for achieving the above object, the DC power supply for supplying the first and second constant voltage (V1, V2) and the operating voltage (V3) receiving an input voltage Feeder 21; At least one fluid temperature sensing unit (22, 22 ') having at least one sensor each sensing a fluid temperature with the first constant voltage (V1); A voltage selector 24 which selects one of the first and second constant voltages V1 and V2 according to the control signal Co from the CPU and outputs the selected voltage Vs; At least one loss calorie sensing unit (25, 25 ') having at least one sensor each sensing a loss of heat with the selected voltage (Vs) from the voltage selector (24); A voltage variation measuring unit (23) for measuring a voltage variation based on the first and second constant voltages (V1, V2); And a CPU controlling the DC power supply 21, the fluid temperature sensing units 22 and 22 ′, the voltage selecting unit 24, the lossy heat sensing units 25 and 25 ′ and the voltage fluctuation measuring unit 23 ( 6); And at least one fluid temperature sensing unit (22, 22 '), a sensor having a standard resistance (Rs) and a temperature dynamic resistance characteristic having a low temperature dynamic resistance while sensing the intrinsic temperature of the fluid; Comprising transducers 22a and 22b, the at least one loss calorie sensing unit 25, 25 'measures the amount of energy consumed by the copper resistance sensor, but the standard resistance and the temperature are low. It is characterized by consisting of a sensor having the dynamic characteristics and the A / D converter (25a, 25b).

Preferably, the input / output unit connected to the CPU 26 further includes a display unit 27-29, a fluid selection unit 30, and a communication port 31.

Also preferably, the dynamic resistance sensor is inserted into the fluid tube, characterized in that penetrates from one surface of the fluid tube to the opposite surface.

Further preferably, the fluid temperature sensing unit 22, 22 ′ includes at least two sensors S11-S14, and the loss calorie sensing units 25, 25 ′ also have at least two sensors S21. -S14).

Hereinafter, a thermally inserted flow meter according to an exemplary embodiment of the present invention will be described with reference to FIGS. 3 to 8.

3 is a block diagram of a thermal insertion type flow measurement apparatus according to the present invention, FIG. 4 is a circuit diagram of the voltage selector of FIG. 3, and FIG. 5 is a detailed view of the fluid temperature sensing unit of FIG. 3. 6 and 7 are examples of a method of inserting a sensor into a fluid tube, and FIG. 8 is a circuit diagram for explaining a relationship between an applied voltage and a measured voltage of each sensor.

First, as shown in FIG. 3, the thermally inserted flow meter of the present invention is a DC power supply that receives AC or DC voltage and supplies first and second constant voltages V1 and V2 and an operating voltage V3. The first and second constant voltages V1 according to the supply device 21, at least one fluid temperature sensing unit 22 and 22 ′ sensing the fluid temperature with the first constant voltage V1, and the control signal Co from the CPU. At least one or more loss calories sensing the loss calories with the selected voltage Vs from the voltage selector 24 and selecting any one of V2) and outputting the selected voltage Vs. And a voltage fluctuation measuring unit 23 for measuring voltage fluctuations based on the first and second constant voltages V1 and V2, and a CPU 26 for controlling them.

The function of each device is described in more detail below.

First, the DC power supply 21 receives general commercial AC power or DC power to generate and supply the first and second constant voltages V1 and V2 and the operating voltage V3. Here, the first constant voltage V1 is a measurement voltage of the fluid temperature sensing unit, and measures an error of the fluid temperature sensing unit and the lossy heat sensor unit, and measures the surface area A and the fluid sensor length 1 of the fluid sensor. The second constant voltage V2 is a voltage for supplying heating energy to the loss calorie sensing unit and calculating residual calories of the sensor, flow rate of the fluid, loss of heat due to heat conduction, and total calorific value, and operating voltage V3. ) Is the voltage for A / D conversion of the analog values measured by the fluid temperature sensor and the lost heat sensor. In general, there is a relationship of V1 < V2 &lt;

The voltage selector 24 is a portion for selectively supplying the first and second constant voltages to the loss calorie sensing unit. When the V1 is selectively supplied, it is time to initialize or correct an error.

The fluid temperature sensing unit 22, 22 'is a sensor for sensing the intrinsic temperature of the fluid. The sensor and the A / D converters 22a and 22b having a standard resistance Rs and a temperature dynamic resistance characteristic having low temperature dynamic resistance. It consists of.

Loss calorimeter sensing unit 25, 25 'is to measure the amount of energy consumed by the dynamic resistance sensor, the sensor and A / D converter (25a, 25b).

The CPU 26 is composed of a processor and a peripheral circuit, and controls the voltage selector, the fluid temperature sensing unit, and the loss calorific sensing unit with control signals Co, Cn, and Cm to select power supplies V1 and V2. In addition, the sensing unit processes the A / D data to calculate the flow rate, flow rate, and fluid temperature, and displays the flow rate, flow rate, and fluid temperature number on the display, and also connects to a remote device. In addition, the above flow rate and flow rate calculation parameters are selected according to the selected values.

Here, Co is a control signal for selecting the voltage of the heat loss sensing unit, the operation of Co and the voltage selector is shown in FIG. When control signal Co is 'high', Q1 is 'on' and outputs V1 (t) as Vs (t). When control signal Co is 'low', Q2 is 'on' and V2 (t) Will be output as Vs (t).

In addition, the other control signals Cm1 and Cm2 are control signals for the CPU to read the values obtained by A / D conversion of voltages applied to a standard resistance and a copper resistance sensor in the fluid temperature sensing unit 22, respectively, and another control signal. Cn1 and Cn2 are control signals for the CPU to read the values obtained by A / D conversion of a voltage applied to a standard resistance and a copper resistance sensor in the lossy heat sensing unit 25, respectively, and Cp1 and Cp2 are voltage fluctuation measuring units 23. C) A control signal for the CPU to read the A / D converted V1 and V2 voltages.

On the other hand, the measurement data Om1 and Om2 are the values obtained by A / D conversion of the voltage applied to the standard resistance and the copper resistance sensor by the fluid temperature sensing unit 22, respectively, and the other measurement data On1 and On2 are the loss calorie sensing unit ( 25) is the value obtained by A / D conversion of the voltage applied to the standard resistance and the copper resistance sensor, and Op1 and Op2 are values obtained by A / D conversion of the voltage V1 and V2 of the voltage fluctuation measuring unit 23, respectively.

In addition, as shown in FIG. 3, the device of the present invention is an input / output unit connected to the CPU 26, and includes a display unit such as a flow rate display unit 27, a flow rate display unit 28, and a fluid temperature display unit 29, and a fluid selector ( 30) and a communication port 31 further.

A schematic configuration diagram of the fluid temperature sensing unit 22 is as shown in FIG. 5.

In other words, the constant voltages V1 and V2 are supplied to the constant voltage source, but are not voltages in a precise sense, and thus are actually voltages that change with time, and thus are represented by V1 (t) and V2 (t). The supply voltage V1 (t) is applied to the series circuit of the standard resistor Rs and the copper resistor R (t), and the voltage measured at each measuring point a and b is converted into a digital value by a 12-bit A / D converter. After the conversion, the measured values Om1 and Om2 are input to the CPU, respectively.

Loss calorie sensing unit 25 also has the configuration as shown in FIG. 5, wherein the constant voltage may be V1 or V2, and the measured output values are On1 and On2. Here, Rs is a precision standard resistance which is non-dynamic resistance, and R0 ± 0.05%, and R (t) is a kind of sensor coated with external vision as a sensor having thermal copper heating and temperature dynamic resistance.

To explain these operations, first, the time variation V1 (t) voltage for measuring the fluid temperature and the time variation V2 (t) voltage for supplying energy are selected to calculate the error of the sensor, and also V1 (t). And the V2 (t) voltage fluctuation can be corrected by the central controller 26 by A / D conversion in the voltage fluctuation control unit 23 of FIG. It is connected in series with a sensor having a dynamic resistance characteristic, and the flow rate can be measured by A / D conversion of the voltage between ab and the voltage between bc, respectively, according to the fluctuating voltages V1 (t) and V2 (t).

Meanwhile, a method of inserting the dynamic resistance sensor into the fluid tube is shown in FIG. 6. In the example of FIG. 6, four sets of two sensors are illustrated. In this case, for example, sensors S1 and S2 may be used as sensors of the fluid temperature sensing unit 22, and C3 and S4 may be used as sensors of the lossy heat sensing unit 25. Each sensing unit may have only one sensor, but it is possible to increase the precision of the measurement error Lennolds function by inserting a plurality of sensors.

FIG. 7 illustrates an embodiment in which the fluid temperature sensing unit 22 and the loss calorific sensing unit 25 are each implemented by four sensors. Each sensor is connected to V1 (t) and V2 (t) through the standard resistor Rs, respectively, and the copper resistors S11-S14 and S21-S24 connected to each standard resistor penetrate one point of the conduit surface. However, it passes through the center point of the conduit through the opposite side of the conduit through the conduit out of the conduit is configured to be grounded. Therefore, the copper resistance is perpendicular to the conduit plane. Since the copper resistance passes through the centerline of the conduit, a more accurate measurement is possible compared to the prior art in which the copper resistance is mounted at a specific position of the conduit.

In addition, the copper resistances do not meet each other because they cross only the center line. The voltages (V11 (t), V12 (t); V21 (t), V22 (t)) applied to the standard resistance and dynamic resistance of each sensor are separately measured, A / D converted, and output to the CPU. Since the summation results in the measurement of fluid information, a relatively accurate measurement is possible even in the presence of vortices and drifts.

On the other hand, with reference to Figure 8 will be described the principle of measuring the flow rate using the flow meter according to the present invention. As shown in FIG. 8, V _A (t) of low voltage is relatively to the series circuit of the standard resistance (R _s1m ) and the non-heating copper resistance (R _1m (t)) of the mth sensor among the four sensors of the fluid temperature sensing unit. V _A (t) and V _B (t) are applied to the series circuit of the standard resistance (R _s2n ) of the nth sensor and the heater dynamic resistance (R _2n (t)) of the heating element. It is adapted to be applied via the switch SW.

First, when the switch SW is connected by switching to the contact point A, a relatively low voltage V _A (t) is applied to both sensing circuits, and therefore, the standard resistances R _s1m and R _s2n of both sensing circuits and copper resistance _{(R 1m (t), R} 2n (t)) , the same voltage, respectively take in, or _{(V Am1 (0) = V} Bm1 (0), V Am2 (0) = V Bm2 (0)), or standard Since a fixed voltage value must be output corresponding to the resistance value of the resistor, the measurement conditions are set to eliminate the manufacturing error and to make accurate measurement with less measurement error by comparing the initial fluid temperature and performing correction. .

Then, the switch contact is switched to the point B, the full-fledged fluid measurement starts. V _B (t) is a voltage much higher than V _A (t), so that the heater copper resistor is heated to generate heat, and therefore has a high resistance value of Ro if there is no fluid flow. However, when there is a flow of fluid, the heat is deprived by the flow rate of the fluid, so that it has a resistance value of R _Bn2 (t) smaller than Ro, and thus the measured voltage (V _Am1 (t), _Am2 V (t)) is a but, the measured voltage sensing unit heat loss variation _{(V Bm1 (t), V} Bm2 (t)) There are influenced. Eventually it is possible to read this change and measure the current flow rate.

If this is expressed as a formula and described.

First, the current i _A and the dynamic resistance r _{1 of the} fluid temperature sensing units 22 and 22 ′ are calculated as in Equation 1.

That is, by measuring V _Am1 (t) and V _Am2 (t), the resistance value of the sensor (dynamic resistance) (S11-S14) can be known, and dividing it by the length of the copper resistor shows the resistivity. Since the resistivity of the resistor reflects the temperature of the fluid, the temperature of the fluid can be known.

Now, when switching the contact point of the switch to the point B and applying a high voltage to the heat loss sensing unit (25, 25 ') to measure the voltage from the heated sensor (S21-S24), the heat loss sensing unit also Equation is established, and when there is a flow of fluid, heat is deprived by the flow of the fluid, so that the temperature of the sensor (S21-S24), which is a heating heater, is applied by the applied voltage (V _B (t)). As the temperature becomes lower than the expected temperature, the increase and decrease of the copper resistance is indicative of the change resistance at the flow rate. Therefore, the flow rate can be known from the Lennolds function, and the conductivity can be known from the Russell number.

Although the present invention has been described with reference to the embodiments shown in the accompanying drawings, the present invention is not limited thereto, and various modifications may be made within a range easily understood by those skilled in the art. Therefore, the limitation of the present invention should be limited only by the following utility model registration claims.

As described above, according to the thermal insertion type flow measuring device according to the present invention, since the flow rate is measured at the entire position instead of one position in the conduit, precise measurement is possible, and the measurement is relatively accurate even when the drift and the vortex are generated. This is possible. In addition, since it is possible to provide a flow meter that can be measured by the supply of a constant voltage source instead of a constant current source, control is easy.

Claims (4)

A DC power supply device 21 receiving an input voltage and supplying first and second constant voltages V1 and V2 and an operating voltage V3; At least one fluid temperature sensing unit (22, 22 ') having at least one sensor each sensing a fluid temperature with the first constant voltage (V1); A voltage selector 24 which selects one of the first and second constant voltages V1 and V2 according to the control signal Co from the CPU and outputs the selected voltage Vs; At least one loss calorie sensing unit (25, 25 ') having at least one sensor each sensing a loss of heat with the selected voltage (Vs) from the voltage selector (24); A voltage variation measuring unit (23) for measuring a voltage variation based on the first and second constant voltages (V1, V2); And CPU 6 for controlling the DC power supply 21, the fluid temperature sensing unit 22, 22 ′, the voltage selecting unit 24, the lossy heat sensing unit 25, 25 ′ and the voltage fluctuation measuring unit 23. ); Including; The at least one fluid temperature sensing unit 22, 22 ′ senses the intrinsic temperature of the fluid, but has a standard resistance (Rs) with a low temperature dynamic resistance and a temperature dynamic resistance sensor and an A / D converter (22a). 22b), The at least one loss calorie sensing unit 25 and 25 ′ measures an amount of energy consumed by the copper resistance sensor, but includes a sensor and an A / D converter having a standard resistance and a temperature dynamic characteristic with low temperature dynamic resistance. 25a, 25b) thermal insertion type flow measurement device characterized in that. The method of claim 1, And an output unit (27-29), a fluid selection unit (30) and a communication port (31) as input / output units connected to the CPU (26). The method of claim 1, The dynamic resistance sensor is inserted into the fluid tube, characterized in that penetrating from one surface of the fluid tube to the opposite surface. The method of claim 1, The fluid temperature sensing unit 22, 22 ′ includes at least two sensors S11-S14, and the loss calorie sensing units 25, 25 ′ also include at least two sensors S21-S14. Apparatus characterized in that the made.