JPS59171814A - Ultrasonic flowmeter - Google Patents

Abstract

PURPOSE:To improve the accuracy of measurement of ultrasonic detectors by providing two ultrasonic pass-type flowrate detectors and one ultrasonic reflection-type flowrate detector, and by selecting these detectors in accordance with the variations in the density and turbidity of a liquid. CONSTITUTION:Two ultrasonic pass-type flowrate detectors 2 and 2A are provided oppositely to each other along the peripheral wall of a conduit 10, and when transmitting and receiving an ultrasonic wave, they detect the mean velocity of a flow from a time of propagation of the ultrasonic wave required for its passing through a liquid. A flowrate transmitter 3 converts said means velocity of the flow into a flow rate q1 and inputs the same to an operator 11. An ultrasonic reflection-type flowrate detector 4, containing transmitting and receiving elements 13 and 14, is provided on the peripheral wall of the conduit 10 for performing the transmission and reception of an ultrasonic wave. The velocity of the flow within a range of a prescribed distance from the peripheral wall of the conduit 10 is detected by this detector. A flowrate transmitter 5 converts this velocity of the flow into a total flow rate q2. A gamma-ray transmitter 8 converts a quantity of transmitted gamma rays into a density gamma. A turbidity detector detects the transmittance of a light. A temperature detecting element detects the temperature of the liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of mosquito treatment to which the invention pertains] The present invention relates to an ultrasonic flow meter that measures the flow rate of industrial water, agricultural water, and other liquids such as lower sea squirts by setting the flow velocity using ultrasonic waves.

[Prior art and its problems]

In general, liquids have little variation in density (therefore, no correction is made for density when measuring flow rate.

However, in the collection pipes where sewage flows in, rainwater from the ground often gets mixed in, and when it rains, not only is it contaminated by pollutants, but also a considerable amount of air bubbles are mixed in, causing a change in the density of the liquid. It turns out that it does. Therefore, it is necessary to accurately measure the flow rate even in such water collection pipes.

The measurement methods of ultrasonic flowmeters are the ultrasonic passing type, which uses the Doppler effect of ultrasonic waves passing through the liquid to detect the average flow velocity along the path, and the ultrasonic passing type, which detects the average flow velocity in the path of ultrasonic waves passing through the liquid. Ultrasonic waves are broadly classified into the ultrasonic reflection type, which uses reflection from objects to approximately calculate the average flow velocity inside the pipe from the flow velocity at a certain distance from the pipe wall. Among these, ultrasonic transmission type flowmeters have good measurement accuracy, but if there are too many bubbles or particles in the liquid, the passage of ultrasonic waves will be blocked, making measurement impossible. There is a risk.

In contrast, ultrasonic reflection flowmeters are capable of measuring the flow rate of liquids containing contaminants and cannot determine the absence of contaminants that can reflect ultrasound waves.

Therefore, for example, if rainwater gets mixed into the sewage and a large number of bubbles form, it becomes impossible to measure with an ultrasonic transmission type flowmeter, but by switching to an ultrasonic reflection type flowmeter, flow rate measurement becomes possible. However, the measurement accuracy of the ultrasonic reflection type flowmeter is lower than that of the ultrasonic transmission type flowmeter. Conventionally, the timing for switching from an ultrasonic transmission type flowmeter to an ultrasonic reflection type flowmeter was the point at which the ultrasonic transmission type flowmeter could not receive reception, that is, the detection signal was cut off (zero). , timing of switching was an internal device.

In addition, since the amount of bubbles tends to fluctuate, switching is often delayed, making measurement impossible. In addition, when calculating a more accurate flow rate value by density correction of the defined value, it is necessary to perform flow correction in synchronization with switching between the ultrasonic passing type and ultrasonic reflection type flowmeters. There were some problems.

[Purpose of the invention]

In view of the above-mentioned points, the present invention aims to provide an ultrasonic flowmeter that effectively solves the problems of the prior art, provides stable flow rate measurement, and has the same measurement accuracy as described above.

[Key points of the invention]

According to the present invention, two pipes are provided in a conduit through which a liquid flows and are arranged opposite to each other so as to detect a flow rate of the liquid with less contaminants than the propagation time of the ultrasonic wave passing through the liquid. one ultrasonic passing type flow rate detector installed in the conduit and detecting the flow rate of the liquid containing the contaminants based on the propagation time of the ultrasonic waves reflected by the contaminants contained in the liquid; an ultrasonic reflection type flow rate detector; a @degree detector installed in the conduit to detect the density of the liquid that changes due to the contaminants; and a turbidity detector installed in the conduit to detect the turbidity of the liquid. a temperature detection element provided in the conduit to detect the temperature of the liquid; A switching setting value calculation function that calculates a switching setting value to be switched to a type flow rate sensor at a required timing according to changes in the density and turbidity of the liquid, and a switching setting value calculation function that calculates the switching setting value to be changed at a required timing, This is achieved by providing a computing unit with a flow value correction computing function for correcting each flow rate detected by the ultrasonic transmission type or ultrasonic reflection type flow rate detector according to changes in the density, turbidity, and temperature. Ru.

[Embodiments of the invention]

Next, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 shows a schematic configuration diagram of an embodiment of the present invention.

In the figure, the ultrasonic passing type 1 includes an ultrasonic passing type flow transmitter 3 having a detector 2.2A, an ultrasonic reflecting type flow transmitter 5 having a detector 4, and a gamma ray source section in this embodiment. 6 and a detector 7, a turbidity transmitter 9A having a turbidity detector 9, a temperature transmitter 15A having a temperature detection element 15, and these transmitters 3, 5, 8, 9A, 15
The flow rate indicator recorder 12 is connected to the computing unit A and the flow rate indicator recorder 12 connected to the computing unit. The two ultrasonic passing type flow rate detectors 2 and 2A are provided facing each other along the circumferential wall of the 5w1o, and when transmitting and receiving ultrasonic waves, the average flow velocity is determined by the propagation time of the ultrasonic waves passing through the fluid. Detect. The flow rate transmitter 3 converts this average flow velocity into a flow rate of 1, which is input to the calculator 11. The ultrasonic reflection flow rate detector 4 houses transmitting/receiving elements 13 and 14 and is connected to a conduit 100.
It is installed on the peripheral wall and transmits and receives ultrasonic waves. Between these transmitting and receiving elements 13° and 140, ultrasonic waves reflected by contaminants in the liquid are received, and depending on the propagation time of the ultrasonic waves, the conduit 100
Detects the flow velocity up to a certain distance from the surrounding wall.

The flow rate transmitter 5 approximately converts this flow rate into an overall average flow rate, 2, and inputs it to the calculator 110. Further, the gamma ray source section 6 and the detector 7 are provided in pairs on the peripheral wall of the conduit 10, and detect the amount of transmitted gamma rays emitted from the gamma ray center section 6 when they pass through the liquid. .

The γ-ray transmitter 8 converts this amount of transmission into density γ, and the arithmetic unit 1
1 input. Note that the turbidity detector 9 optically detects the light transmittance in the liquid, and the transmitter 98 converts this light transmittance into turbidity d, which is used as the manual power of the computing unit II. Further, the temperature output system 15 detects the liquid temperature, and the temperature transmitter 15A inputs the temperature T to the calculator 11. It's 1 for Pura, l1jt
I! - The device 11 has a switching set value calculation function and
It has a tool function.

Figure 2 is a complete diagram showing the switching setting points of the ultrasonic transmission type and ultrasonic reflection type flow rate detectors that switch according to changes in fluid density.
(B) is a case in which only suspended matter is used as a contaminant and no air bubbles are included. In the figure, a curve P indicates that air bubbles are mixed into water whose density γ is 1 g/cm, and the density γ decreases with time t, and as the air bubbles decrease, the density γ increases and becomes l g/cm.
It shows that it approaches 3. At this time, range A and range C are ranges in which the flow rate is detected by the ultrasonic passing type flow rate detectors 2 and 2A. Further, range B is a range where the flow rate is detected by the ultrasonic reflection type flow rate detector 4. Point P ] + P
2 is a detector switching point for switching from the ultrasonic passing type flow rate detector 2, 2A to the ultrasonic reflecting type flow rate detector 4, and from the ultrasonic reflecting type flow rate detector 4 to the ultrasonic passing type flow rate detector 2, 2A. be. Such a switching point P].

P2 has a density γ of ε1. At the point where ε2 changes, if 1° and 2 are set as the switching setting value, an appropriate timing width t2 can be set.
It should have t+e and be able to prevent noise during switching. Note that at point P3, due to an increase in the number of bubbles in the liquid, the output signal of the ultrasonic transmission type flow rate detector 2 becomes zero, making it impossible to measure the flow rate.

In addition, curve R shows that in water whose density γ is 1 g/c, the density γ increases with time due to the mixing of suspended matter, and as the suspended matter decreases, the density γ decreases to 1 g/crn”. In this case, range A and range C are the ranges where the flow rate is detected by the ultrasonic passing type flow rate detector 2 and two people. 4 is the range in which the flow rate is detected.

Points R1r and R2 indicate the detection of switching from the ultrasonic passing type flow rate detector 2, 2 people to the ultrasonic reflection type flow rate detector 4, and from the ultrasonic reflection type flow rate detector 4 to the ultrasonic passing type flow rate detector 2° and 2 people. This is the switching point. Such switching points R1r R2
, the density γ is ε3. This ε3. ε
If 4 is the switching setting value, the timing width t3-t4 is set as appropriate.
It should be possible to prevent hunting during switching. Furthermore, point R3 is due to an increase in turbidity in the liquid.
This is the point at which the output signals of the ultrasonic passing type flow rate detectors 2 become zero and flow rate measurement becomes impossible.

Figure 2 (B) is a case where air bubbles or suspended matter are mixed into the liquid alone, or they often coexist.

Therefore, the switching setting value S l (S 1 + S 2 +
b 3 + 84 ) are the initial setting values A jr (,, I + 22 +
73 + , il 4 ), constant Q for density γ,
b (eLI + , R2+ CL 3 + (L 4
), constant bi7 (1!r 1+薯2
．． A general formula like the IJ formula is established.

S 1:+l'ir+ab'γ+bru 1d
......(1) Based on this formula (1), the arithmetic unit 11
The switching set value calculation function of , respectively, calculates the switching set value b I (S+ +
S2 + b 3 + S4) is calculated.

By the way, the attenuation rate of ultrasonic waves with respect to density changes depending on the type of turbidity in the liquid, and the degree of light scattering changes depending on the fineness or coarseness of the particles of turbidity, so turbidity changes. The attenuation rate of ultrasonic waves changes depending on the wavelength of the sound waves. Therefore, based on the location conditions such as sewers or rivers, the constant, j,.

k should be selected appropriately.

In addition, ultrasonic transmission type and ultrasonic reflection type flow transmitter 3,
5, the detected flow rate, □2, 2 is the temperature T determined by the fluid temperature transmitter 15A, and the turbidity d determined by the turbidity transmitter 9A, respectively.
, and the density T from the density transmitter 8.

If this corrected flow rate is Q, general equations such as equation (2) and equation (3) are established.

Q-YoF+Cg:+,T,,<,r)・・・・・・・・・
(2) Q ”” J” 2 (tl ” r T+ c
l + γ) (3) By the way, the equation (2) is the corrected flow rate Q when the flow rate fP+ is detected by the ultrasonic passing type flow rate transmitter 3. However, equation (3) is still the same as the flow rate by the ultrasonic reflection flow rate transmitter 5.
This is the corrected flow rate Q when 2 is detected. In this way, the calculator 11 switches between the ultrasonic passing type and the ultrasonic reflecting type flow rate detectors 2, 2A, and 4 using the switching setting value calculation function, and in synchronization with this switching, calculates the flow rate correction. The flow rate 11+i2 is corrected by the function according to changes in liquid density, turbidity, and temperature, improving measurement accuracy.

Next, FIG. 3 shows a schematic configuration diagram of another embodiment of the present invention. In the figure, parts having the same functions as those in FIG. 1 are designated by the same reference numerals. The ultrasonic flowmeter 16 includes ultrasonic passing type and ultrasonic reflection type flow rate detectors 2, 2A, 4,
Density detector 7, temperature detection element 15, turbidity detector 9, and integrated transmitter 1 which receives the detection signals of these detectors 2, 2A, 4, 7.9, and temperature detection element 15 as inputs.
7 and a flow rate indicator recorder 12. Integrated transmitter 1
7 is a microcomputerized switching setting value calculation function that converts each detection signal and calculates the switching setting value, and an ultrasonic passing type and ultrasonic reflection type flow rate that are switched by this switching setting value calculation function. Detector 2.2A,
This calculation unit has a flow rate correction calculation function that corrects the detection signal from 4 according to density, turbidity, and temperature. In this way, the ultrasonic flowmeter 16 has a simplified configuration due to the integrated transmitter 17, and is easy to handle.

Next, FIG. 4 shows a schematic configuration diagram of still another embodiment of the present invention. In the figure, the ultrasonic flowmeter 18 includes a first integrated detector 19, a second integrated detector 2o, a turbidity detector 9,
It is composed of a total transmitter 17 and a flow rate indicator recorder 12. As shown in FIG. 5, the first integrated detector 79 is installed on the peripheral wall of the conduit 100, and as shown in FIG.
Inside, an ultrasonic transmission type flow rate detection transmitter/receiver 22, an ultrasonic reflection type flow rate detection transmitter/receiver (A elements 24, 25, a temperature detection element 15, and a radiation density detection element 26) are integrated by filling synthetic resin or the like. Also, the second combined detector 2
0 is installed on the circumferential wall of the conduit 100 facing the first integrated detector 19, and as shown in FIG. 28 is integrally housed with a filler such as synthetic resin. The radiation detection element 27 is removably installed in the radiation source insertion tube 28 in the form of a cartridge, and can be easily replaced when the radiation source deteriorates. In this way, the ultrasonic flowmeter 18 is integrated into the first and second combined detectors 19,20, making it more compact and easier to attach to the conduit 10.

〔Effect of the invention〕

As explained above, according to the present invention, there are two ultrasonic transmission type quantity detectors, one ultrasonic reflection type flow rate detector,
a gravity detector that detects density that changes due to contaminants in the liquid; a turbidity detector that detects turbidity in the liquid; a temperature sensor that detects the temperature of the liquid; A switching setting value calculation function that calculates a switching setting value for switching between a type and an ultrasonic reflection type flow rate detector at a required interval according to changes in the density and turbidity of the liquid, and a switching setting value for this switching setting value. A function having a flow rate correction calculation function that corrects each flow rate of the ultrasonic transmission type or ultrasonic reflection type flow rate detector according to changes in density, turbidity, and temperature of the liquid in synchronization with switching by the calculation function. By being equipped with 4 detectors, the ultrasonic detector can be smoothly switched to a passing type or a reflective type according to changes in density and turbidity due to contaminants contained in the liquid, and can be synchronized with this switching. This makes it possible to appropriately correct the detected flow rate of each ultrasonic detector, improving measurement accuracy, and furthermore, by consolidating each detector and transmitter, its assembly is simplified, miniaturized, and It has advantages such as easy handling.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of switching set points of an ultrasonic transmission type and an ultrasonic reflection type flow rate detector that switch according to changes in fluid density. ) is a case in which only air bubbles are included as a contaminant and no turbid matter is included; (B) is a case in which only a turbid substance is in a contaminant and no air bubbles are included; FIG. 3 is a schematic configuration diagram of another embodiment of the invention; The figures are schematic diagrams of still another embodiment of the present invention, FIG. 5 is a schematic diagram of the first integrated detector, and FIG. 6 is a schematic diagram of the second integrated detector. 1.16.18: Ultrasonic flow meter, 2, 2A: Ultrasonic passing type flow rate detector, 4: Ultrasonic reflection type flow rate detector, 6: γ-ray source, 7: R-ray detector, ll: Arithmetic unit, 17: integrated oscillator, 19: first integrated detector, 20: second integrated detector. Patent applicant Fuji Electric Seizo Co., Ltd. Agent Masu Takeo Yokoya-' Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1) two ultrasonic passing type flow rate detectors installed in a conduit through which a liquid flows and facing each other so as to detect the flow rate of the liquid with few contaminants based on the propagation time of the ultrasonic waves passing through the liquid; one ultrasonic reflection type flow rate detector provided in the conduit and detecting the flow rate of the liquid based on the propagation time of ultrasonic waves reflected by the contaminants contained in the liquid; a density detector that detects the changing density of the liquid; a turbidity detector that is installed in the conduit and detects the turbidity of the liquid; and a temperature detection element that is installed in the conduit that detects the temperature of the liquid. , the switching setting value for switching the ultrasonic passing type flow rate detector to the ultrasonic reflection type flow rate detector or the ultrasonic reflection type detector to the ultrasonic passing type flow rate detector at the required timing is set according to the density and turbidity of the liquid. A switching setting value calculation function calculates the selection according to the change in the switching setting value calculation function, and in synchronization with the switching by this switching setting value calculation function, the respective detected flow rates by the ultrasonic passing type or ultrasonic reflection type flow rate detector are calculated as follows. Flow rate correction calculation that performs correction calculation according to changes in liquid density, turbidity, and temperature 'J1. An ultrasonic flow meter that is characterized by being equipped with a calculator that performs functions.