JPH02291923A - Flow-rate display device of pulse transmission type flowmeter - Google Patents

Abstract

PURPOSE:To make it possible to display a minute flow rate without special machining on a disk wherein pulse generating slits are cut by feeding back and controlling the amplitude of a sawtooth wave so that the peak voltage of the sawtooth wave is constant. CONSTITUTION:A waveform shaping circuit 12 receives pulses which are transmitted from a flowmeter when a flow rate is measured and shapes the waveform. The, an edge detecting differential circuit 13 detects the rise-up of the pulse based on the shaped pulse and outputs a rise-up signal. Thereafter, a sawtooth wave generating circuit 14 converts the pulse into a sawtooth wave based on the rise-up signal. An amplitude control circuit 15 feeds back and controls the amplitude of the sawtooth wave so that the peak voltage of the sawtooth wave becomes constant. A step wave generating circuit 17 generates n-step comparison voltages whose values become high stepwise every time the pulse is detected. Then, a comparator 16 compares the voltages of the sawtooth waves and generates a new pulse signal every time the voltages agree. A counter 3 counts transmitted 16 pulse trains. The number of the counted 3 pulses is converted into a flow rate per hour, and the flow rate is displayed on a display device 4.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a flow theory display device for a pulse-generating flowmeter such as a wet gas meter.

(Prior art) As shown in Fig. 5, the display device of a pulse transmitting type flowmeter consists of a timer (1), a gate circuit (2), a counter (3), and an indicator (4). The pulses emitted when measuring the flow rate are input from (A) and counted directly on a predetermined time base, which is then converted to flow rate per hour and displayed on the display (4). ing.

For example, in the case of a wet gas meter, a pulse emitting type flowmeter (A>) is divided into an outer cylinder (5) filled with a liquid such as water or oil, as shown in Figures 2 to 4. A total wI cylinder (7) divided into 3 to 5 chambers by a plate (6) is rotatably provided, and the gas entering from the inlet (8) is partially immersed in the sealing liquid of the measuring cylinder (7). Introduce the gas into the chamber <9>, use the gas pressure to push it up, exhaust the gas in the opposite chamber (9'), and rotate the meter cylinder (7) in the direction of the arrow V, meter atfl (7). a disk (11) that is attached to the shaft (10) of and rotates together with the shaft (10);
The photoelectric sensor (13) is turned on and off to generate pulses through slits (12) formed at regular intervals along the periphery of the sensor.

For example, in the case of a 109 meter (minimum measurable flow rate 10n/R), one rotation of the indicator tube, that is, one rotation of the disk, is the gas flow filo.
j, and the number of slits is 0.1 per slit! 100 slits/round are provided so that J is formed.

Therefore, this is the ON state of the photoelectric sensor. OFF, that is, pulses are generated 100 times in one rotation of the disc, and one pulse represents 0.11.

Therefore, the display device counts the number of pulses for 36 seconds,
This is multiplied by 100 to display the flow 1 (j) per hour (3,600 seconds).

(Problem to be Solved by the Invention) Therefore, the number of display digits in the above conventional device is 10 fJ/8. ′
1 order, for example 8404)/hour, this indication means that the flow rate is greater than or equal to r 840.11 /hour and less than 850 fJ/hour, and 10.1
Even if you try to adjust 1 to the flow of 1/hour order, there is no display for the digits below it, so it is difficult to set it unless you are an expert.

In addition, if no pulse occurs in 36 seconds, the flow rate display will be O when the flow rate is less than 101/hour, so when testing large gas consuming equipment such as a boiler, for example, When measuring the flow rate when only the pipe burner is burning, or when measuring continuously with a standard wet gas meter that matches the capacity of the meter during meter verification, use the wet gas meter to measure minute flow rates. Accurate measurements cannot be made when attempting to do so.

Therefore, one possibility is to increase the number of slits, for example, 1000 slits/circumference, and by doing so, it becomes 0.01 Jl/slit 1 ~ lj
/ hours, but it is technically difficult to form such a large number of slits precisely at the same corner.

The present invention was made in view of the above-mentioned problems of the prior art, and its main purpose is to make it possible to display minute amounts of 5i without adding any special processing to a disk with slits for pulse generation. The purpose is to make it easier to make fine adjustments to the flow rate.

(Means for Achieving the Object) In order to achieve the above object, the display device for a pulse emitting type flowmeter of the present invention provides a display device for a pulse emitting type flowmeter that displays pulses emitted from the pulse emitting type flowmeter in conjunction with measurement of a flowing wall. A waveform shaping circuit that inputs and shapes the pulse; an edge detection differentiation circuit that detects the rising edge of the pulse based on the shaped pulse and outputs a rising signal;
a sawtooth wave generation circuit that converts the pulse into a sawtooth wave based on the rising signal; an amplitude il1 control circuit that feedback controls the amplitude of the sawtooth wave so that the peak voltage of the sawtooth wave is constant; a staircase wave generation circuit that generates an n-step comparison voltage that increases each time the pulse is detected, compares the comparison voltage with the sawtooth wave voltage, and generates a new pulse signal each time the voltages match; It is equipped with a comparator, a counter that counts the pulse train transmitted from the comparator on a predetermined time base, and a display that converts the number of pulses counted by the counter into a flow rate per time and displays it.

<<Operation>> The pulse-emitting type flowmeter display device configured as described above generates pulses with an interval of 1/n of the time between the previous pulse and the current pulse transmitted from the pulse-emitting type i-meter. The number of pulses is multiplied by n, and the flow rate up to 1/n of the flow rate that can be converted by one pulse transmitted from the flow meter is displayed.

(Example" Hereinafter, one embodiment of the present invention will be described based on the drawings.

This embodiment shows a case where the pulse emitting type flowmeter (A) is a wet gas meter, and the wet gas meter (A) is similar to the conventional wet gas meter described above, and is equipped with water or oil as shown in FIGS. 2 to 4. A metering iκ1 (7) is rotatably provided inside the Gaisho (5) which is filled with a liquid such as the above, and the inside is divided spirally into 3 to 5 chambers by a partition plate (6).
The gas entering from 8) is transferred to the chamber (9) of the meter hanging tube (7) which is partially immersed in sealing liquid, and the gas pressure is used to push it up and exhaust the gas in the opposite chamber (9゛). Let me, total M
The cylinder (7) was rotated in the direction of the arrow, and the disks (11) were attached to the shaft (10) of the cylinder (7) and rotated together with the shaft (10). The photoelectric sensor (13) is turned ON by the slit (12). It has a conventionally well-known structure in which a pulse is generated by turning it off, and 100 slits (12) are formed along the periphery of the disk (11).

Therefore, in the wet gas meter <A), for example, the gas flow f
fi10Jl t-[[m (7) F1 rotation L
In the case of a 610jl meter, one pulse will be generated every 0.11 times the gas flows.

This pulse is then input to the display device fffi (B) connected to the wet gas meter (A).

The display device (B) includes a waveform shaping circuit (1) as shown in FIG.
2), edge detection differentiation circuit (13), sawtooth wave generation circuit (14), amplitude control circuit (15), comparator (1B)
, staircase wave generation circuit (17), timer (1), gate circuit 2). Counter (3). First, the waveform shaping circuit (12) inputs pulses from the wet gas meter (A) and shapes the waveform, and then transforms this into a differential wave by the edge detection differentiation circuit (13). It detects the rising edge of the pulse and outputs a rising signal.

The sawtooth wave generation circuit (14) receives the rising signal, integrates the pulse, and converts it into a sawtooth wave.

At this time, the amplitude control circuit (15) adjusts the amplitude of the sawtooth wave to keep the peak voltage of the sawtooth wave constant based on the voltage set by the reference sawtooth wave generation voltage setting circuit (18). feedback control.

The above-mentioned toothed wave iii whose imaging width has been controlled enters a comparator (16), and its voltage is compared with a comparison voltage entered from a staircase wave generation circuit (17).

The staircase wave generating circuit (11) sequentially generates 10 levels of comparison voltages starting from the lowest voltage at each input pulse, that is, every sawtooth period, until a voltage of 1 corresponding to the peak voltage of the sawtooth wave is reached.

Comparison 3 <16> receives 10 levels of comparison voltage from the staircase wave generation circuit (17) in order from the lowest voltage every time the sawtooth wave is inputted from the sawtooth wave generation circuit (14), and calculates the voltage of the sawtooth wave. is compared with a comparison voltage, and a new pulse signal is output each time the voltage of the sawtooth wave matches the comparison voltage that is successively accepted.

Therefore, 10 pulses will be generated from one sawtooth wave.

In other words, one pulse input from the wet gas meter (A>) is divided into 10 equal parts, so the comparator (16)
One of the pulse trains outputted from corresponds to 0.011 gas M.

The pulse train output from the comparator (16) is processed by the timer (
Gate circuit (2) with the time base of 36 seconds set in 1).
) through the counter (3) and the display (4).
to be displayed.

The reason for setting timer (1) to 36 seconds is to calculate the number of counts per hour and F! by multiplying by 100. This is because l can be easily converted.

The display (4) converts the number of pulses counted by the counter (3) into flow per hour and displays the result.

Therefore, up to the order of 1 g will be displayed on the display (4).

In this example, the comparison voltage was divided into 10 stages and the pulses from the wet gas meter (A> were converted into a 10 times as many pulse train. However, by dividing the comparison voltage into more stages, it was converted into even more pulse trains. Accordingly, it becomes possible to display even smaller digits.

(Effects) Since the present invention has the above configuration, it has the following effects.

(1) Add a new pulse with an interval of 1/n of the time between the current pulse and the previous pulse emitted by the pulse emitting flowmeter, and based on this new pulse, calculate the flow rate per hour. Since it is converted into and displayed, the number of display digits is increased compared to conventional display devices without increasing the number of disk slits in the flowmeter, making it possible to display even smaller digits.

(2) As mentioned above, it is possible to display minute flow rates;
Easy to finely adjust flow rate.

(3) Also, by shortening the time base for counting, it is possible to display the lowest value than before. ;! can be displayed in short cycles.

[Brief explanation of drawings]

Fig. 1 is a functional block diagram showing the configuration of a display device of a pulse emitting type flowmeter showing an example of the present invention, and Figs. 2 and 3 are explanatory diagrams of a wet gas meter shown as an example of a pulse emitting type flowmeter. FIG. 2 schematically shows a vertical front view, and FIG. 3 schematically shows a vertical side view. FIG. 4 is a perspective view illustrating the pulse transmitting section of the pulse transmitting type current ω meter. FIG. 5 is a functional block diagram showing the configuration of a display device of a conventional pulse emitting type flowmeter. Special characteristic counter 4: Display waveform shaping circuit 13: Differential circuit sawtooth wave generation circuit 15: Amplitude control circuit comparator
17: Staircase wave generation circuit Pulse emission type flow B1 meter (wet gas meter) Display device Seibu Gas Co., Ltd. Kinmon Manufacturing Co., Ltd. Masamitsu Ota

Claims (1)

[Claims] a waveform shaping circuit that inputs and shapes the pulses emitted from the pulse-emitting flowmeter when measuring the flow rate; an edge detection differential circuit that detects the rising edge of the pulse based on the shaped pulse and outputs a rising signal; a sawtooth wave generation circuit that converts the pulse into a sawtooth wave based on the rising signal; an amplitude control circuit that feedback controls the amplitude of the sawtooth wave so that the peak voltage of the sawtooth wave is constant; A staircase wave generation circuit that generates an increasing n-level comparison voltage every time the pulse is detected, and a comparison that compares the comparison voltage with the sawtooth wave voltage and generates a new pulse signal each time the voltages match. A pulse transmitter, comprising: a counter that counts the pulse train transmitted from the comparator on a predetermined time base; and a display that converts the number of pulses counted by the counter into a flow rate per hour and displays it. Flow rate display device for type flowmeter.