JPS6152409B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention selects a specific flowmeter adapted to measure a so-called minute flow rate, which has a relatively small flow rate, from among a plurality of flowmeters with different flow measurement ranges, and corrects the measurement of the flowmeter. The present invention relates to a flow rate measuring device that can measure a flow rate with extremely high accuracy.

Generally, fuel carburetors used in automobiles etc.
During factory production, each product is inspected for quality.
Currently, whether or not the fuel consumption amount of mixed gas is within an appropriate error range is fixedly measured only for a specific air flow rate. Therefore, it is not possible to maintain high accuracy in a wide range of flow rate measurement ranges to determine whether appropriate fuel consumption is being achieved in response to wide variations in the airflow flowing through the ventilate pipes, and differential pressure flow rates cannot be used. Due to the principle of the meter, there are errors caused by physical changes such as changes in viscosity due to temperature of the measured fluid, so it is extremely inadequate for testing fuel vaporizers, and it is difficult to obtain highly accurate fuel vaporizers. I had the inconvenience of not being able to do it.

Furthermore, it is often required that the flow rate measurement range be relatively diverse and that the flow rate measurement can be performed with high accuracy.

The present invention has been made by focusing on the above points,
Because the flow rate measurement range is relatively diverse, such a wide flow rate range is subdivided using multiple flowmeters with different flow rate measurement ranges, and a specific flowmeter corresponding to the measured flow rate is artificially or It is an object of the present invention to provide a flow rate measuring device which is capable of automatically selecting and measuring the flow rate, and which is capable of providing a highly accurate measuring function while correcting the instrumental error by comparing the flow meter with a reference flow meter.

To explain in more specific detail, a positive displacement flowmeter with a relatively large flow rate measurement range, such as a non-circular gear type flowmeter or a Roots type flowmeter, is placed upstream as a reference flowmeter, and Differential pressure flowmeters such as capillary flowmeters and orifice flowmeters with small flow measurement ranges are connected in series as multiple flowmeters with various flow measurement ranges, and the superiority of the differential pressure flowmeters is An object of the present invention is to provide a flow rate measuring device that can accurately measure a flow rate by utilizing responsiveness.

In general, positive displacement flowmeters have the advantage of being able to perform actual measurements where the effects of changes in the density and viscosity of the fluid to be measured can be ignored; however, even if the viscosity of the fluid changes due to temperature, etc., the accuracy of flow measurement is not affected. However, since the flow rate measurement is generally obtained as a digital signal, there is a disadvantage that the responsiveness is less preferable than that of an analog signal in order to obtain the instantaneous flow rate output. On the other hand, the aforementioned differential pressure flowmeter has the disadvantage that measurement errors occur when the viscosity of the fluid changes due to temperature changes, but because it is obtained as an analog signal, it has the characteristic of extremely good responsiveness. .

The present invention has been achieved by paying attention to the above-mentioned points, and one embodiment of the present invention will be described in detail below.

Reference numeral 1 indicates a positive displacement flowmeter such as a non-circular gear type flowmeter (trade name: oval flowmeter) which has a relatively large flow rate measurement range. Differential pressure flow meter 2 ₁ ,
The configuration is such that flow rate corrections of 2 ₂ , 2 ₃ , . . . can be performed.

3 is a main pipe in which the positive displacement flowmeter 1 is interposed;
₁ , 4 ₂ , 4 ₃ . . . are branch pipes in which one or more differential pressure type flowmeters 2 ₁ , 2 ₂ , 2 ₃ . Differential pressure flowmeters 2 ₁ , 2 ₂ , 2 ₃ . . . are differential pressure flowmeters 2 that measure different minimum flow rates, although the flow ranges overlap each other in the illustration.
Four flowmeters are used, from ₁ to ₂₄ , which measure the maximum flow rate, including an orifice type flowmeter, a laminar flow type flowmeter, etc. 5 is each differential pressure type flowmeter 2 ₁ , 2 ₂ , 2 ₃ . . .
A differential pressure transmitter that can detect and measure the differential pressure before and after...
The flow rate measurement of each differential pressure type flow meter 2 ₁ , 2 ₂ , 2 ₃ . . . can be obtained as an analog quantity. 6 ₁ , 6 ₂ , 6 ₃ ... are each differential pressure flowmeter 2
₁ , 2 ₂ , 2 ₃ . . . The differential pressure branch pipe 8 connected to the downstream side of the differential pressure transmitter 5 and communicating with the downstream differential pressure pipe 7 of the differential pressure transmitter 5 is an upstream differential pressure pipe of the differential pressure transmitter 5. It is connected to the upstream side of flowmeters 2 ₁ , 2 ₂ , 2 ₃ . 9 ₁ , 9 ₂ , 9 ₃ ... are the differential pressure branch pipes 6
₁ , 6 ₂ , 6 ₃ ... can be opened and closed automatically or manually by means of differential pressure switching solenoid valves interposed therebetween. 10 ₁ , 10 ₂ , 10 ₃ ... are branch pipes 4 ₁ ,
The selection solenoid valves provided at 4 ₂ , 4 ₃ . . . can be opened and closed automatically or manually like the aforementioned solenoid valves. 11 is an A/D converter for converting the analog signal of the differential pressure transmitter 5 into a digital signal; 12
is the digital signal from the reference flowmeter 1 and the A/D
This shows an arithmetic circuit that can receive digital signals from the converter 11 and perform correction calculations, and further includes the arithmetic circuit 1.
2, the solenoid valves 9 ₁ , 9 ₂ , 9 ₃ ... and 10
₁ , 10 ₂ , 10 ₃ . . . are provided with a transmission mechanism that can automatically select and switch between them, and are electrically connected to each other via an interface circuit 12a.

That is, the arithmetic circuit 12 is computerized to selectively operate a specific differential pressure type flowmeter in response to changes in the flow rate of the flowing fluid, and furthermore, it is possible to select a specific differential pressure type flowmeter from the circuit 12. A D/A that can convert digital quantities into analog quantities is provided with a signal transmitting unit 13 that can display the corrected flow rate, and a signal transmitting unit 14 that displays and transmits the corrected flow rate.
It is also possible to use a converter 15 to obtain the corrected flow rate as an analog signal.

The operation of the present invention will be explained based on the above configuration.

The components indicated by chain lines in FIG. 1 are shown equivalently to the circuit configuration shown in _{FIG .} , 2 ₃ ... can be opened and closed in various ways. However, since the flow of fluid gradually increases from zero, the differential pressure flowmeter ₂₁ that measures the minimum flow rate range is always open at the beginning of fluid flow. Therefore, both electromagnetic valves 9 ₁ and 10 ₁ are "open".

Then, the flow rate gradually increases and the differential pressure flow meter 2
Solenoid valves 9 ₂ and ₁ are installed so that when the flow rate reaches a level that cannot be measured with 1, the next differential pressure flowmeter ₂ is activated.
0 ₂ becomes "open", and the solenoid valves 9 ₁ and 10 ₁ , which had been kept "open" until now, become "closed".

In this way, the differential pressure flowmeters 2 ₁ , 2 ₂ . 9n and 10n are "open", all other electromagnetic valves are "closed", and flow rate measurement is then performed continuously.

Therefore, even if each differential pressure flow meter 2 ₁ , 2 ₂ . Since the digital quantity from 1 is continuously compared and corrected, the instrumental error correction is extremely accurate and can improve measurement accuracy.

In the embodiment, the arithmetic circuit 12 is configured such that a specific flowmeter having an optimal flow rate measurement range can be selected from a large number of differential pressure flowmeters 2 ₁ , 2 ₂ , 2 ₃ , etc. arranged in parallel. However, instead of such automatic control, the solenoid valves 9 ₁ , 9 ₂ , 9 ₃ . . .
It is also possible to manually operate 10 ₁ , 10 ₂ , 10 ₃ . . . to select a specific flow meter adapted to the flow rate.

Next, referring to FIG. 3, it shows a case where the accuracy of an automobile carburetor A is tested as an object to be inspected.A fuel chamber 17 is connected to a pipe 16 facing one side of the carburetor A. The chamber 17 is connected to a fuel supply pipe via a float needle valve 18, and the fuel supply pipe corresponds to the main pipe 3 in the above embodiment, and the portion indicated by B is the Figure 1 and 2
2 shows the measurement configuration shown in the figure.

Therefore, by changing the amount of air flowing through the carburetor A 19, the amount of fuel sucked and atomized from the pipe 16 can be varied, and the consumption amount can be freely measured in relation to the amount of air. Therefore, vaporizer A
As a result, the accuracy of the vaporizer A can be tested to an extremely high level, and a high quality vaporizer A can be obtained.

Incidentally, the fuel consumption amount corresponding to the change in the air amount can be transmitted to the outside as a digital signal or converted into an analog signal from the correction amount signal transmitter 14 through the operation shown in the above-described embodiment.

In the above embodiments of the present invention, a positive displacement flowmeter was used alone as a reference flowmeter, but the details were only explained for the case where a plurality of differential pressure flowmeters were used to measure the flow rate. It is also possible to use the differential pressure type flowmeter alone, and in such a case, it goes without saying that the configuration of the electromagnetic valve can be omitted.

Further, in the present invention, a positive displacement flowmeter 1 as a reference flowmeter and each differential pressure flowmeter 2 ₁ , 2 ₂ , 2 ₃ . . .
A selection solenoid valve 10 that connects the branch pipes 6 ₁ , 6 2 , 6 3 as close as possible and switches between the branch pipes 6 1 , 6 ₂ , 6 ₃ .
₁ , 10 ₂ , 10 ₃ , ... to prevent the temperature rise of the fluid due to heat generation from causing measurement errors, the differential pressure solenoid valve 9 should be installed as far downstream as possible, and the differential pressure solenoid valve 9 should be installed as far downstream as possible.
₁ , 9 ₂ , 9 ₃ , ... are the selection solenoid valves 10 ₁ ,
It is preferable to drive in conjunction with 10 ₂ , 10 ₃ , . . . .

As described above, in the present invention, the differential pressure type flowmeter measures the flow rate with high sensitivity with respect to the reference flowmeter, and the instrumental error correction is continuously performed by the reference flowmeter, so that the flow rate accuracy is improved. It can be measured extremely efficiently, and because it is equipped with multiple differential pressure flowmeters with different flow measurement ranges, a specific flowmeter suitable for the fluid flow rate can always be selected automatically or manually. Therefore, it has features that make measurement operations easy.

Furthermore, in the present invention, a plurality of differential pressure flowmeters are basically provided downstream of the reference flowmeter, and the reference flowmeter always performs instrumental error correction of a specific flowmeter. However, it is also possible to perform correlation correction processing on correction coefficients of other differential pressure flowmeters other than those actually corrected using coefficients that have been actually corrected in advance.

Furthermore, it is extremely accurate when measuring a relatively wide range of flow rates, such as when measuring the fuel flow rate of a carburetor, or when measuring the fuel flow rate of various types of carburetors depending on the displacement type of an automobile internal combustion engine. A computer-linked automated device that can measure the flow rate and perform adjustment operations based on the flow rate test results, such as an automated device that adjusts the carburetor flow rate based on the fuel flow rate measurement results, such as a flow rate test stand for an automobile carburetor. It has the characteristics of being able to provide a flow measurement device with high responsiveness, wide flow measurement range, and high accuracy.

In addition, during the above-mentioned carburetor flow rate test, the fuel flow rate measurement range is automatically switched according to the driving mode, and after the flow rate measurement is completed at the final mode point of the test driving mode, correction calculations can be performed with the actual measured value of the reference flowmeter. It has many features such as:

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing one embodiment of the flow rate measuring device according to the present invention, Fig. 2 is an explanatory diagram showing the configuration of the flow rate measurement channel of the main part of the same, and Fig. 3 is a device used as a testing device for a vaporizer. It is an explanatory diagram showing an example. 1... Reference flowmeter, 2 ₁ , 2 ₂ ... Differential pressure flow meter, 5... Differential pressure transmitter, 9 ₁ , 9 ₂ ... 10 ₁ , 1
0 ₂ ...Valve mechanism (electromagnetic valve), 12... Arithmetic circuit,
12a...Interface circuit.

Claims (1)

[Claims] 1. When measuring the flow rate, a positive displacement flowmeter is used as a reference flowmeter, and on the downstream side of the reference flowmeter,
A plurality of differential pressure flowmeters with different measurement flow rate ranges are connected in parallel, and the flow rate measurement signal is normally obtained from the differential pressure flowmeter, and the actual flow rate measurement signal obtained based on the reference flowmeter is used to calculate the difference. A flow measurement device that can correct instrumental error changes based on physical changes in the measured fluid in the flow signal of a pressure flowmeter. 2 A positive displacement flowmeter is used as a reference flowmeter, and multiple differential pressure flowmeters connected in parallel with different measurement flow ranges are automatically or manually selected using separate valve mechanisms. A flow rate measurement device that can measure the flow rate while correcting the flow rate by operating a specific differential pressure flow meter corresponding to the flow rate. 3. When measuring flow rate, a positive displacement flowmeter is used as a reference flowmeter, and on the downstream side of the reference flowmeter,
A single differential pressure type flowmeter is connected, and the flow rate measurement signal obtained from the differential pressure type flowmeter includes instrumental error changes based on physical changes in the measured fluid using the measured flow rate signal obtained based on the reference flowmeter. A flow rate measurement device that allows for correction. 4 A differential pressure transmitter is interposed in one or more differential pressure flowmeters connected in parallel, with or without a valve mechanism, and the flow rate of the fluid passing through the differential pressure flowmeter is determined by the differential pressure transmitter. 3. A flow rate measuring device according to any one of claims 1 to 3, wherein the flow rate measuring device is configured to obtain the flow rate as an analog signal. 5. Claim 1, wherein a reference actual flow rate measured by a reference flowmeter and a measured flow rate obtained by a differential pressure type flowmeter are compared and calculated in an arithmetic circuit to constantly measure a corrected flow rate. The flow rate measuring device according to items 1 to 4. 6 Connect the reference flowmeter and multiple differential pressure type flowmeters at minimum position intervals, and place the valve mechanism of the differential pressure type flowmeter as a solenoid valve on the downstream side to reduce measurement errors due to temperature rise of the test fluid due to heat generation. Further, the valve mechanism for switching each differential pressure type flowmeter is configured as a solenoid valve, and the valve mechanism is automatically selected in conjunction with the electromagnetic valve, and the corrected flow rate can be measured by operating a specific differential pressure type flowmeter. Flow rate measuring device according to range 2, 4, or 5.