JPS6123925A - Measuring method of instantaneous flow rate - Google Patents

Abstract

PURPOSE:To obtain a precise measured value by dividing a flow rate obtained from a constant number of flow rate signals from a flow rate pulse transmitters by the time required to output the constant number of signals, and thus calculating the mean flow rate in one period of a flow rate. CONSTITUTION:A pulse signal from the flow rate pulse transmitter is inputted to a central processing part 7 through an input/output device 8. Then, the flow rate N of one predetermined period is divided by the total pulse time of the one period to calculate the instantaneous flow rate Q. Then, the central processing part 7 updates and stores the instantaneous flow rate Q. Thus, the calculating operation is performed individually every time a pulse is inputted from a pulse transmitter PL1 or PL2. Then, the central processing part 7 is cleared on the basis of the instantaneous flow rate Q and controls the opening extents of flow rate control valve operating parts V1 and V2 according to a mixture ratio. Consequently, the amount of fed oil is displayed on a display meter 5 precisely.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an instantaneous flow rate measurement method for a flowmeter that produces periodic fluctuations between the flow rate and the flow rate measurement output axis, The present invention relates to an instantaneous flow rate measurement method that can be suitably used in machines.

[Prior art] In an ideal flowmeter that does not cause periodic fluctuations between the flow rate and the rotation of the flow rate measurement output shaft, the instantaneous flow rate is determined by the pulse transmitted from a pulse transmitter attached to the flow rate measurement output shaft. It can be found by dividing the flow rate flowing between pulses by the time between pulses.

However, most flowmeters, such as the four-piston flowmeters used in gas stations, experience periodic fluctuations of, for example, every 90 degrees. To determine the instantaneous flow rate with these flowmeters, divide the amount of one cycle by the number of pulses emitted during that period to determine the flow rate of one pulse interval, and then divide this amount by the time required for one pulse interval. I was finding it by dividing. but,
Although the values obtained in this way are accurate on average, they are inaccurate momentarily and at every pulse interval. When controlled using this measurement method, even if the actual mixing ratio is correct, the apparent mixing ratio obtained from the instantaneous flow rate determined by the above measurement method will be incorrect, and the valves in the flow path may be unnecessarily controlled to open and close. become.

[Purpose of the Invention] The present invention has been made in view of the above-mentioned reports, and its purpose is to obtain a highly accurate instantaneous flow rate in a flowmeter that causes periodic fluctuations between the flow rate and the flow rate measurement output shaft. The object of the present invention is to provide a method for measuring instantaneous flow rate.

[Structure of the Invention] The instantaneous flow rate according to the present invention is determined by dividing the flow rate obtained from a fixed number of flow signals from a flow rate pulse generator by the time required to output the fixed number. .

[Operations and Effects of the Invention] Therefore, the instantaneous flow rate is determined as the average flow rate during one cycle of the flowmeter every time a pulse is transmitted. The measured values are therefore very accurate and are therefore suitable for use in blender weighing machines, for example.

[Preferred Embodiment] When implementing the present invention, it is preferable to use a control device for measurement, and the control device has a storage area corresponding to the number of pulses for one cycle, and stores the latest inter-pulse time. It is preferable to provide a memory unit for the time between pulses that sequentially updates and stores the oldest memory during storage.

Further, it is preferable that the operating portion of the flow rate control valve that controls the respective flow rates of the two liquids be constituted by a pulse motor, and that the opening degree of the flow rate control valve is controlled by a signal from a control device.

[Example] The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an example of a refueling machine in which the present invention is implemented.

The refueling Ial is provided with, for example, a line L1 for metering regular gasoline R and a line L2 for metering high-octane gasoline H, so that both are mixed and refueled from a refueling nozzle 3 via a refueling hose 2. Refueling machine 1
There is a blend ratio setting button 4 for setting the blend ratio, a refueling meter 5 for displaying the amount of refueling, and a refueling nozzle 3 for refueling 1.
! A nozzle switch SW that is turned on whenever the switch is removed from the nozzle switch 11 is provided. Incidentally, when the blend setting button 4 is pressed, a lamp 4a (FIG. 2) lights up and is displayed on the pressed button 4.

The line L1 is equipped with a pump P1 driven by a motor PMI, a flow rate pulse transmitter PL1 attached to the output shaft [an actuating unit V1 composed of a flow meter M1 and a pulse motor that controls the flow port. A flow rate control valve Va is interposed, and the flow rate pulse transmitter PL1 is configured to transmit a pulse every time the rotation axis of the meter M1, that is, the flow rate measurement axis, rotates by a constant angle. The equipment installed in the line L2 will be given the suffix "2" and a redundant explanation will be omitted. These motors PM1, PM2, flow rate pulse transmitters PLI, PL2, flow rate control valve operating parts ■1, V2,
The nozzle switch SW1, the blend ratio setting button 4, and the fuel supply amount indicator 5 are connected to a control device 6 provided in the fuel supply machine 1 via a line (not shown).

In FIG. 2, the control device 6 is provided with a central processing section 7, which is connected via an input/output device 8 to each device such as the motors PM1 and PM2. Therefore, input signals from each of the devices are input to the central processing unit 7 via the input/output device 8,
Further, signals from the central processing section 7 are transmitted to each of the above-mentioned devices via an input/output device 8. In addition to the central processing unit 7, the control device 6 includes a ROM (ROM>9) that stores one cycle's worth of flow rate, program, calculation formula 8, etc.
A RAM (RAM), that is, an inter-pulse time storage unit 10, which has a storage area corresponding to the number of pulses corresponding to a cycle and sequentially updates and stores the oldest memory when storing the updated inter-pulse time, and a clock 11. There is.

When refueling, the worker presses the blend ratio setting button 4 according to the customer's order, and the central processing unit 7 accordingly sets the blend ratio setting button 4.
Turn on the light 4a. There, the worker turned to the refueling nozzle 3.
When i is removed, the nozzle switch SW is turned on, and based on that signal, the central processing unit 7 returns the refueling amount indicator 5 to zero, sets the flow control valve operating parts V1 and V2 to the required opening degree, and adjusts the flow rate. Open the control valve ■a1■b and turn the motor PM
1, PM2 is activated, and pumps P1 and P2 are driven.

Then, refueling work is performed. During this refueling operation, pulse signals are input from the flow rate pulse transmitters PLI and PL2 to the central processing unit 7 via the input/output device 8, and are based on the instantaneous flow rate determined by the instantaneous flow rate measurement method of the present invention described below. The mixing ratio is calculated by using the mixing ratio, and if the mixer is out of order, the flow rate control valve is controlled to open or close.

Next, one measuring method of the present invention will be explained mainly with reference to FIG.

When the pulse signal from the flow rate pulse generator is input to the central processing unit 7 via the input/output device 8 (step S1), the central processing unit 7 calculates the interpulse time measured by the clock 11 as shown in FIG. The previous memory is updated and stored in the n address specified by the step described later in the interpulse time storage unit 10 (step S2>).Then, the central processing unit 7 It is determined whether the address corresponds to the number of pulse intervals nmax (step 83), and if n is not nmax, that is, if NO in step S3, the next interpulse time is stored in the interpulse time storage section 10. The address is stored to specify n=n+1, that is, the next address (step S4
). When n is equal to nmax, that is, in the case of YES in step S3, the pulse m time storage section 10 stores it to specify that n=1, that is, address 1, is the address at which to store the next interpulse spacing (step S3). 85).

In this way, when the latest inter-pulse time is stored in the inter-pulse time storage section 10, the oldest memory is sequentially updated, and nmax inter-pulse times are always stored. Then, each time one pulse signal is input and the inter-pulse time is updated in the inter-pulse time storage section 10, the central processing section 7 inputs the nm value stored in the inter-pulse time storage section 10.
The ax number of inter-pulse times are added (step S6), and then the instantaneous flow IQ is calculated by dividing the preset flow fMN for one period by the sum of the inter-pulse times for one period determined in step S6. (Step 87). Finally, the central processing unit 7 updates and stores the instantaneous current IQ (step S8
). These steps are the pulse generators PLI, PL
Each time a pulse is input from 2 onwards, it is executed individually. Then, the central processing section 7 controls the opening degrees of the flow m control valve operating sections V1 and V2 based on the mixture ratio calculated based on this instantaneous flow ff1Q.

As a result, oil blended to the correct blend ratio is supplied, and the amount of oil supplied is displayed on the oil supply amount indicator 5.

[Summary] As explained above, according to the present invention, the instantaneous flow rate is obtained by dividing the flow rate during one cycle by the sum of the inter-pulse times during one cycle, so a highly accurate measurement ratio can be obtained. For example, a blender meter is suitable for use in a machine.

[Brief Description of the Drawings] Fig. 1 is an explanatory diagram of a refueling machine implementing the present invention, Fig. 2 is a block diagram showing an example of a control device implemented in the present invention, and Fig. 3 is an explanatory diagram of a refueling machine implementing the present invention. A flowchart showing the program of the control device, and FIG. 4 is an explanatory diagram of the interpulse time storage section. PLl, PL2...Flow rate pulse transmitter Vl,
■2... Flow m control valve operating section N... Flow fjlT for one cycle... Inter-pulse time for one cycle 6... Control device 10... Inter-pulse time storage section

Claims (2)

[Claims] (1) An instantaneous flow rate measurement method characterized in that the flow rate obtained from a fixed number of flow rate signals from a flow rate pulse generator is calculated by dividing the flow rate by the time required to output the fixed number. (2) The instantaneous flow rate measuring method according to claim 1, wherein the constant number of flow rate signals is a value obtained from periodic fluctuation characteristics of the flow meter.