JP3225691B2 - Open channel flow meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an open channel flow rate measuring device for validating a flow signal only when there is a flow velocity in measuring the flow rate of an open channel.

[0002]

2. Description of the Related Art A surface velocity type flow meter shown in FIG. 2 is usually used for measuring a flow rate in an open channel. The surface velocity type flow meter 10 is C
The main body 11 includes a PU 12, a display 13, an output port 14, and the like, a diaphragm pressure sensor 15 for detecting a water level in an open channel, an ultrasonic flow meter 16, and the like. The CPU 12 has a pressure sensor 15 and an ultrasonic current meter 16.
From the water level signal and the flow velocity signal from the controller, the flow velocity is corrected by correcting the flow velocity with the water level using the flow velocity distribution curve of the open channel previously determined, and the water level, the flow rate, etc. are displayed on the display 13 and the output port 14 Outputs a flow signal.

[0003]

In the flow rate measurement of the open channel by the above-mentioned surface velocity type flow meter, even if the channel is blocked up to a gate or the like and the flow velocity is 0, if the water pressure (water level) is present, the flow rate can be reduced. There is a drawback that an output signal is output and the flow rate is erroneously measured.

[0004] The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide an unnecessary flow signal output when a water channel is blocked or a flow rate is extremely small. An object of the present invention is to provide an open channel flow velocity measuring device that does not perform the measurement.

[0005]

To achieve the above object, an open channel flow measuring device according to the present invention comprises a first pressure sensor for detecting a water level in an open channel, and a first pressure sensor for detecting a flow velocity. A sound velocity meter, a surface velocity type flow meter having an arithmetic unit for calculating and outputting the open channel flow rate from the water level signal and the flow rate signal, a second pressure sensor for detecting the water level of the open channel, and a second sensor for detecting the flow rate. From the ultrasonic flowmeter 2 and the water level signal and the flow velocity signal, there is no backflow in the open channel, the pressure is above the specified level, and the normal flow velocity is above the specified level. A flow rate detector having an arithmetic unit that outputs a contact signal when the three conditions are satisfied; a flow rate signal of the above-mentioned surface velocity type flow rate signal and a contact signal from the flow rate detector are input; Analog output with signal enabled Characterized by comprising a Kensa.

[0006]

The surface velocity type flow meter detects the water level with a pressure sensor and corrects the flow velocity signal of the ultrasonic flow velocity meter to obtain the flow velocity. For this reason, the open channel is blocked and backflow occurs,
If there is no water level or the flow rate is extremely low, erroneous measurement may result in output of an unnecessary flow rate signal.

[0007] The flow rate detector detects three conditions: no backflow is generated from the water level signal and the flow velocity signal; the pressure is higher than a specified value; and the normal flow rate is higher than a specified value. Only when the condition is satisfied, a contact signal is output to the sequencer to make the flow velocity signal valid, so that an unnecessary flow rate signal is not output from the sequencer.

[0008]

An embodiment of the present invention will be described with reference to FIG.
The same components as those shown in FIG. 2 are denoted by the same reference numerals, and the description thereof will not be repeated.

In FIG. 1, reference numeral 20 denotes a contact output flow rate detector which, like the surface velocity type flow meter 10, detects a main body 21 composed of a CPU 22, a display 23, an output port 24 and the like, and a water level and a flow velocity in an open channel. A pressure sensor 25 and an ultrasonic flow meter 26. The pressure sensor 25 and the ultrasonic current meter 26 detect the water level and the flow velocity in the open channel. A sequencer 28 receives an analog flow signal converted by a DA converter (not shown) of the surface velocity flow meter 10 and a contact signal from the flow velocity detector 20 and outputs an analog flow signal when there is a contact signal. It is.

The CPU 22 of the flow velocity detector 20 determines from the water level signal and the flow velocity signal from the pressure sensor 25 and the ultrasonic velocity meter 26 that (1) no backflow, (2) water level is specified or more, and (3) normal flow velocity is specified. (1) to (3)
When all of the above are satisfied, a contact output of “with reverse speed” is output from the output port 24 to the sequencer 28.

If at least one of the above (1) to (3) is not satisfied, there is no contact output, so that a backflow occurs due to damming, the water level does not satisfy the specified value, or the flow is normal. An erroneous measurement signal such as when the flow velocity is below the specified value is not erroneously output from the sequencer 28. Therefore, the flow signal from the sequencer 28 is a flow rate when a normal flow velocity exists.

[0012]

Since the present invention is configured as described above, the following effects can be obtained.

(1) When measuring the flow rate in an open channel, when the channel is blocked or when the flow rate is extremely small, unnecessary erroneous measurement flow rate signals need not be output.

(2) For this reason, danger such as erroneous control due to an erroneously measured flow signal can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view of an open channel flow rate measuring device according to an embodiment.

FIG. 2 is a configuration explanatory view of an open channel flow rate measuring device according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Surface speed type flow meter 11 ... Surface speed type flow meter main body 12, 22 ... CPU 13, 23 ... Display 14, 24 ... Output port 15, 25 ... Pressure sensor 16, 26 ... Ultrasonic flow meter 20 ... Contact output Flow detector 21 ... Flow detector body 28 ... Sequencer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01F 1/00 G01F 1/66

Claims (1)

(57) [Claims] 1. A first pressure sensor for detecting a water level in an open channel, a first ultrasonic current meter for detecting a flow velocity, and an arithmetic unit for calculating and outputting an open channel flow rate from the water level signal and the flow velocity signal. A surface velocity flow meter having: a second pressure sensor for detecting the water level of the open channel, a second ultrasonic current meter for detecting the flow velocity, and no backflow in the open channel from the water level signal and the flow velocity signal. That the normal flow velocity exists above the specified pressure,
A flow rate detector having an arithmetic unit that outputs a contact signal when the three conditions are satisfied, and a flow rate signal of the surface velocity type flow rate signal and a contact signal from the flow rate detector are input; An open channel flow rate measuring device, comprising: a sequencer that makes a flow signal valid and outputs an analog signal only when a signal is present.