JPH0238822A - Apparatus for detecting liquid level in piping - Google Patents

Abstract

PURPOSE:To easily and rapidly detect the surface of the liquid in piping from the outside by transmitting an ultrasonic wave toward the liquid in the piping from the outside and performing the counting operation of a clock pulse on the basis of the reflected wave from the bottom surface of the liquid and that from the surface of the liquid. CONSTITUTION:When the water level in piping 14 is inspected, the frequency of a clock pulse generator 9 is set corresponding to the diameter of the piping 14 at first by a pipe diameter selecting dial 8 to generate a measuring clock pulse. An ultrasonic vibrator 2 is brought into contact with the bottom surface of the piping 14 to transmit an ultrasonic wave SAW and, at this time, the first reflected wave RAW 1 reflected by the bottom surface 15a of water 15 and the second reflected wave RAW 2 passed through the bottom surface to be reflected from the surface 15b of the water are received by an ultrasonic transmitter-receiver 3. These reflected waves are detected by a water surface reflected wave detector 6 to give a signal to a counter and the number of pulses are counted to display the water level in the piping 14 on an analogue meter 13 on the basis of the counted number of pulses.

Description

[Detailed Description of the Invention] [Field of cooperation with Teikyo] This invention relates to a liquid level detecting device in piping, and more specifically, to a liquid level detecting device using ultrasonic waves.

[Prior Art] Generally, in large tanks, a liquid level detection device such as a liquid level gauge is used as a means for detecting the liquid level. In such a liquid level detection device, by installing sensor portions at strategic points inside the tank, the liquid level can be detected near the tank or in a monitoring room.

[Problem to be solved by the invention] However, when performing repair or maintenance work on piping lines, it is necessary to know in advance whether there is fluid in the piping or the liquid level. It is difficult to apply liquid (ke) detection equipment.In other words, piping lines are laid in various directions such as horizontally, inclinedly, and vertically, and the D diameter of the piping is not constant, and the number of laid piping lines is huge. The presence or absence of internal fluid for individual piping,
It is very difficult to know the liquid level etc.

This invention was made in view of the above-mentioned problems, and an object of the present invention is to provide a liquid level detection device that can easily and quickly detect the liquid level from outside the pipe. Another object of the present invention is to provide a small and portable liquid level detection device. Furthermore, the present invention aims to provide a simple and inexpensive liquid level detection device.

[Means for Solving the Problems] The present invention includes an ultrasonic transmitting/receiving means for transmitting ultrasonic waves from the outside of a pipe toward a liquid inside the pipe and receiving the reflected waves; Upon transmission, a first detection signal is output based on the reception of the first reflected wave generated at the bottom surface of the liquid, and a first detection signal is output based on the reception of the second reflected wave generated at the liquid surface. a liquid surface reflected wave detector that outputs the second detection signal, a clock pulse generator that generates a clock pulse, and counts the number of pulses of the clock pulse based on the input of the first detection signal. a clock pulse counter that starts and ends based on input of the second detection signal; and a liquid level indicating means that indicates the liquid level based on the number of pulses counted by the clock pulse counter. By providing this, the above problem is solved.

Further, in the above configuration, further comprising a frequency setting means for setting the frequency of the clock pulse in accordance with the pipe diameter of the piping, and the liquid level indicating means is counted by the clock pulse counter. The above problem is solved by using a digital/analog converter that converts the number of pulses generated into an analog signal and an analog meter that gives a liquid level indication according to the analog signal as the liquid level indicating means.

1 Effect 1 The liquid level detection device of this invention uses ultrasonic waves! Since the liquid level can be easily and quickly detected from outside the container. In addition, since it is equipped with a frequency setting means that can set the frequency of the clock pulse for liquid level detection according to the diameter of the piping, it is possible to accurately measure the liquid with an analog meter regardless of the size of the piping. Be able to detect the position.

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows one embodiment of the present invention, and is a block diagram showing the electrical configuration of an in-tube ice image detection device.

In this figure, ■ is the main body of the device, and 2 is an ultrasonic transducer. In the apparatus main body 1, 3 is an ultrasonic transmitter/receiver, which has an ultrasonic transmitting function and an ultrasonic receiving function. This ultrasonic transmitter/receiver 3 is provided with a variable resistance knob 4 for adjusting sensitivity.

5 is a timing signal generator for generating ultrasonic oscillation timing signals, etc.; 6 is a water surface reflected wave detector;
It outputs a detection signal when it receives a received signal of reflected waves of ultrasonic waves generated at the bottom and surface of water.

In the following, the reflected wave at the bottom of the water will be referred to as a first reflected wave, and the reflected wave at the liquid surface will be referred to as a second reflected wave. In addition, corresponding to these reflected waves, a first detection signal,
This is called a second detection signal. The water surface reflected wave detector 6 is provided with a variable resistor 7 for adjusting a dead zone.

This variable resistor 7 for adjusting the dead zone is provided in order to prevent the detection of reflected waves other than those from the bottom or surface of the water (details will be described later). 8 is a dial for selecting the pipe i1, which indicates the diameter of the pipe whose internal water level is to be detected. For example, 2OA, 50A, 80A11
00A, 20OA.

There are scales that indicate the pipe diameter, such as 300A, 500A, and 700A (for example, 20A indicates a pipe diameter of 20 mm). 9 is a water level detection clock whose frequency can be varied.
It is a clock pulse generator that generates pulses, and is selected using the tube diameter selection dial 8. :'
The frequency is set according to k.

This frequency is set in order to obtain a constant number of clock pulses from the reception of the first reflected wave to the reception of the second reflected wave, regardless of the pipe diameter when the pipe is full of water. 1 died in . Specifically, this frequency is determined as follows. That is, the inner diameter of the tube is 17, the propagation speed of the ultrasonic wave in water is ~r, and the distance from the reception of the first reflected wave to the second
Let T be the time required to receive the reflected wave, then T=2
The L/V relational expression is established. Therefore, in order to always generate N clock pulses during time T, regardless of the tube diameter, frequency F may be set to F=T/H. Although the above N can be set arbitrarily, in the following, N=
The case where it is set to 100 will be explained. 10 is a counter that counts the number of clock pulses manually. This counter 10 starts counting the number of pulses from the time when the first detection signal outputted from the water surface reflected wave detector 6 is inputted, and continues counting until the second detection signal is inputted. 11
10 is a D/A converter that converts the number of pulses counted into an analog signal, 12 is an amplifier that amplifies the analog signal, and 13 is a pointer that swings according to the amplified analog signal to adjust the water level. This analog meter is a zero-indication analog meter.This analog meter I3 becomes full scale and indicates "full" when 100 clock pulses are counted by the counter IO.

Next, the operation of the i+2-groove in-pipe water level detection device will be described with reference to FIGS. 1 to 3.

FIG. 2 is a scene explanatory diagram showing a work scene, and FIG. 3 is a time chart showing operations. For example, to check the water level in a pipe with a pipe diameter of 100A, first use the pipe diameter selection dial 8.
Adjust the pointer to the 10OA scale position. As a result, the clock pulse generator 9 is set to a frequency corresponding to the pipe diameter of 100A, and generates a measurement clock pulse PLSl under the set frequency (see Fig. 3 (b)). .

Next, the work piece brings the ultrasonic vibrator 2 into contact with the bottom of the piping 1.
7\~V to the transmitter (waveform shown in Figure 3 (a)) 0
The ultrasonic SAW sent (1 yen) first hits the bottom surface 1 of the water 15.
51 and received by the ultrasonic transceiver 3 as a first reflected wave RAW.

The ultrasonic transceiver 3 receives a first reflected wave R at time T.
When A W I is received (see FIG. 3 (a)), the received signal is sent to the water surface reflected wave detector 6. Water surface reflected wave detection′
A″A6 supplies the first detection signal KEN I triggered by the above received signal to the counter IO. The counter !0 receives the first detection signal KEN I at time T1 and counts the number of pulses from this. (See Figure 3 (b)).The water surface reflected wave detector 6 detects the first reflected wave R.
When receiving AWI, variable resistor 7 for dead band adjustment is applied.
The reflected ultrasonic wave is not detected for a certain short period 101 defined by . This is, for example, the first
Due to the reflected wave 1'(A', VI), multiple reflections may occur between the outer and inner walls of the pipe 14. Therefore, by the time the second reflected wave RAW2 arrives, the dead zone period is canceled.

On the other hand, the ultrasonic waves S A to V that have passed through the bottom surface of the water 15 travel through the water, reach the water surface 15b, are reflected there, and are transmitted as second reflected waves 1 (A W 2) of the ultrasonic transducer 2. Thus, the second reflected wave RΔW2,
When received by the ultrasonic transmitter/receiver 3 at time point '2 (see FIG.
Supply OF< to 0. counter! 0 finishes counting the number of pulses upon receiving the second detection signal KFN2 at time T (see FIG. 3(b)). At this time, for example, 70
If clock pulses are counted, then I) /
An A converter 11 supplies an analog signal corresponding to 70 pulses to an analog meter 13 via an amplifier 12. As a result, the analog meter 13 indicates "full"
It shows that the water level is 7/10 compared to the actual time. Further, for example, when 30 nozzle pulses are counted, the analog meter 13 displays that the water level is 3/10 of the level when the tank is "full", as described above. Further, if, for example, 100 clock pulses are counted, analog meter 13 will indicate full scale, indicating "full." Next, pipe diameter 2
If you want to check the internal water level of a 00A pipe, use the same operation as described above to set the clock pulse generator 9 to a pipe with a diameter of 20A.
F of this set frequency is set to a frequency corresponding to A.
The clock pulse PLS2 is generated (Fig. 3 (c)).
reference). Thereafter, the same operating procedure as described above is performed.

At this time, for example, if clock pulses on the 70 side are counted, the analog meter 13 will display that the water level is 7/10 compared to when it is "full". Also, for example, if 30 clock pulses are counted, the analog meter 13 will be 3/I compared to when it is "full".
Displays that the water level is Q.

Additionally, if 100 clock pulses are counted, the analog meter 13 indicates "full."

According to the above configuration, even if the pipe diameter is 5,
The ratio of internal water level can be accurately determined.

In addition, in the example of "double series", the case where the piping is arranged horizontally has been described, but it can also be applied to the case where the pipe is arranged vertically. In this case, the water level can be checked by placing an ultrasonic vibrator on the side of the vertical pipe. Of course, 100 pulses are counted below the water surface, and the number of pulses is not measured above the water surface, so the water level can be determined.

In addition, in the above example, the case of detecting the water level was described, but it is not limited to this, and other liquids (
For example, it can be applied to liquid level detection of oil (petroleum).

Further, in the above example, a case was described in which an analog meter was used, but the same effect as described above can be obtained by using a digital display as the water level indicating means.

[Effects of the Invention] As explained below, since the liquid level detecting device for piping according to the present invention emits ultrasonic waves, the liquid level can be easily and quickly detected from outside the piping. In addition, it is possible to obtain a small and portable one-liquid detection device. Also,
Easy and cheap! You can build two.

Furthermore, the liquid level detection device of the present invention sets the frequency of the clock pulse for liquid level detection in accordance with the diameter of the piping.
tl filter, the liquid level can be accurately detected even with an analog meter without affecting the pipe diameter of the pipe.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, in which ultrasonic waves ('II
FIG. 2 is a block diagram showing the electrical configuration of the in-pipe water level detection device used, FIG. 2 is a scene explanatory diagram showing a working scene, and FIG. 3 is a time chart showing the operation of the same embodiment. 2... Ultrasonic transducer (ultrasonic transmitting/receiving means), 3
... Ultrasonic transmitter/receiver (ultrasonic transmitter/receiver), 6
...Water surface reflected wave detector (liquid surface reflected wave detector) 8
・・・・・・Pipe diameter selection dial (frequency setting means),
9... Tarokk pulse generator, 10...
...Counter (clock pulse counter), 11...
...D/A converter, I3...analog, meter (display means), 14...piping, 15a...
...Low surface of water (low surface of liquid), 15b... Water surface (liquid surface) Applicant Ishikawajima Harima Heavy Industries Co., Ltd.

Claims (2)

[Claims] (1) An ultrasonic transmitting/receiving means that transmits ultrasonic waves from the outside of the pipe toward the liquid inside the pipe and receives the reflected waves; Based on the reception of the resulting first reflected wave, the first
a liquid surface reflected wave detector that outputs a detection signal and outputs a second detection signal based on reception of a second reflected wave generated at the liquid surface; and a clock pulse generator that generates a clock pulse. a clock pulse counter that starts counting the number of pulses of the clock pulse based on the input of the first detection signal and ends counting the number of pulses of the clock pulse based on the input of the second detection signal; - A liquid level detecting device in piping, comprising: liquid level indicating means for indicating the liquid level based on the number of pulses counted by a pulse counter. (2) The liquid level detection device in a pipe according to claim 1, further comprising a frequency setting means for setting the frequency of the clock pulse in accordance with a diameter of the pipe, and a liquid level indicating means. A digital /
A liquid level detection device for piping, characterized in that the liquid level indicating means includes an analog converter and an analog meter that gives a liquid level indication according to the analog signal.