JP2895682B2 - Interface level detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting the level of an interface between a settled sludge and a supernatant in a sludge treatment tank, and more particularly to the prevention of malfunction of the device when a sludge solution is charged and a settled sludge is withdrawn. is there.

[0002]

2. Description of the Related Art In purifying a liquid containing sludge, a liquid containing sludge is separated into a sludge (2) and a supernatant (3) in a sludge treatment tank (1) as shown in FIG. ,
The sediment (2) is discharged from the lower part of the treatment tank (1) for treatment. In this case, in order to know an appropriate discharge time of the settled sludge, the depth H ₁ from the liquid level (4) to the interface (5) between the supernatant liquid (3) and the settled sludge (2), or the interface (5) ) it is necessary to know the such depth H ₂ of up to the bottom of the tank (1a) from. Therefore, a method using an ultrasonic wave is widely used as a means. For example, as shown in FIG. 2, a wave transmitting / receiving surface is immersed in a liquid near the liquid surface (4) to provide an ultrasonic wave transmitter (6) and a wave receiver (7). The ultrasonic wave is transmitted from the transmitter (6) toward the tank bottom at a constant time interval from the transmitter (6) as a drive signal using a pulse output from the transmitter (9) controlled by the synchronization circuit (8). Wave S. Then, a reflected wave or a leaked transmitted wave from the interface (5) or the tank bottom (1a) is received, and the received wave is added to a receiver (amplifier circuit) (10) to be enveloped, signal processed, and signal recorded. And the envelope output is converted into a digital signal by an analog-to-digital converter (11), and is temporarily stored in a memory (12) ((12a) is a write circuit, and (12b) is a read circuit). In addition to the CRT (14) via the readout display circuit (13) in synchronization with the transmission, the liquid level image (a), the interface image (b), and the tank bottom tank (c) are displayed. The depth scale (16) is set on the CRT (1) by the depth scale generation circuit (15).
4) Display simultaneously on the screen so that the depth of the interface and the like can be read directly. And from further example transmission of the transmission wave S in FIG. 3 by the calculator (17) (a), from time to the received reflected wave R ₁ from the interface based on this calculation and the depth from the liquid surface to the interface This is digitally displayed (18) to enable direct reading, and furthermore, when the measured interface level reaches a set value by providing a depth setting circuit, the discharge valve is opened to automatically discharge the deposited sludge. That has been done.

[0003]

However, the apparatus for detecting an interface level in a sludge treatment tank as described above has the following problems to be solved. That is, immediately after the liquid (raw sludge) containing the sludge for the treatment, the sludge is widely dispersed in the treatment tank (1). Also, at the time of discharging the settled sludge (2), it is inevitable that the settled sludge, especially at the upper part of the interface, is dispersed in the supernatant. Thus until a certain time has elapsed, for example, as shown in FIG. 3 (b), causing a large number of reflected wave R _3, R ₄ ...... R _N from many distributed sludge. Thus for example, the reflected wave R ₃ misidentified and the reflected wave R ₁ from the interface, the erroneous measurement state. In addition, before reaching the predetermined interface position, the sludge discharge valve of the treatment tank (1) is opened to discharge the fresh sludge that has just been introduced as it is, causing environmental pollution, and There is a major problem that takes time to reduce the processing efficiency.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an interface level detecting apparatus which can surely prevent the above-mentioned problems from occurring.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to provide the following means, namely, [providing an ultrasonic transmitter / receiver near the surface of the sludge liquid charged into the sludge treatment tank, and using the transmitted ultrasonic wave and the ultrasonic transmitter / receiver. A sludge input switch and a sludge which are supplied when a raw sludge is charged into a sludge treatment tank and when a settled sludge is discharged, in an interface level detection method for detecting an interface level between a supernatant liquid and sludge from a received wave based on the sludge. A discharge switch is provided to control the interface level detection device by the output of each contact point, to perform the time until the sludge settles, the measurement to be missed, and the notification thereof].

[0006]

With the above arrangement, it is possible to prevent the measurement of the interface level from being erroneously performed when the raw sludge is introduced into the sludge treatment tank and when the settled sludge is discharged, and there is no possibility of causing environmental pollution.

[0007]

Next, an embodiment of a method for detecting an interface level according to the present invention will be described with reference to the drawings. FIG. 1 is a block circuit diagram of an embodiment of the present invention, in which the same reference numerals as in FIG. 3 indicate the same parts. In FIG. 1, (1) is a sludge treatment tank,
(6) is a transmitter, (7) is a receiver, (() is a synchronous circuit,
(9) is a transmitter, (10) is a receiver, (11) is an analog / digital converter, (12) is a memory, (12a) is a write circuit, (12b) is a read circuit, and (13) is a display circuit. , (14) is a CRT, (15) is a depth scale signal generation circuit, (16) is a depth scale, (17) is a depth calculator,
(18) is a digital display of depth, and the above configuration is the same as the conventional one. (19) is a raw sludge input detection switch, which is manually turned on when raw sludge is input. (20)
Is a timed circuit, and the switch (19) is connected to the receiver (1).
0) the missing contact (19a) for grounding the input terminal, the operating contact (19b) of the missing alarm buzzer (21) and the closing contact (19c) of the sludge discharge valve (22) of the treatment tank (1). The sludge input detection switch (19) has a timed circuit (2
0) automatically turns off after the time required for the dispersed sludge to settle. (23) is a settling sludge discharge detection switch, (24) is a time limit circuit, and switch (23) is a missing contact (23) for grounding the input terminal of the receiver (10).
a) and the operating contact (23b) of the missing alarm buzzer (25)
And a switch (2) turned on when the settled sludge is discharged.
3) is automatically turned off by a timed circuit (24) after a necessary time has elapsed. In this manner, the detection of the interface level is stopped when the sludge is charged and discharged, so that an erroneous interface level is not given. Further, there is no possibility that the inputted sludge is discharged.

Although the present invention has been described above, other known methods can be used as the missing measurement method. Also, using a contact signal for detecting the input or discharge of the raw sludge, a digital value of the interface depth at the time of the input of the raw sludge is used. Display and interface image display
It can be kept at the value before raw sludge is introduced, or can be set to zero or full scale value.

[0009]

According to the present invention, the following excellent effects can be obtained. It is possible to always perform stable measurement of the interface level. Environmental pollution due to malfunctions can be prevented, and the processing capacity can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an embodiment of an interface level detection method according to the present invention.

FIG. 2 is an explanatory view of a settling sludge treatment method and an explanatory view of a conventional interface level detection method using ultrasonic waves.

FIG. 3 is a waveform chart for explaining the operation of the interface level detection method using ultrasonic waves.

[Explanation of symbols]

 (1) Sludge treatment tank (1a) Tank bottom (2) Sludge (3) Supernatant (4) Liquid level (5) Interface (6) Transmitter (7) Receiver (8) Synchronous circuit (9) Transmitter (10) Receiver (11) Analog-to-digital converter (12) Memory (12a) Write circuit (12b) Read circuit (13) Display circuit (14) CRT (15) Depth scale signal generation circuit (16) Depth scale (17) Depth calculator (18) Digital display of depth (19) Settling detection switch (19a) Missing contact (19b) Missing alarm buzzer operating contact (19c) Discharge valve closing contact ( 20) Timed circuit (21) Missing alarm buzzer (22) Sludge discharge valve (23) Settling sludge discharge detection switch (23a) Missing contact (23b) Alarm buzzer operating contact (24) Timed circuit (25) Missing alarm buzzer

Claims (1)

(57) [Claims] An ultrasonic transmitter / receiver is provided near the liquid level of sludge fed into a sludge treatment tank, and an interface level between the supernatant and the sludge is detected from the transmitted ultrasonic wave and a received wave based on the ultrasonic wave. A sludge input detection switch and a sedimentation sludge discharge detection switch that are turned on when raw sludge is put into a sludge treatment tank and when sedimentation sludge is discharged, and an interface level detection device is provided by a contact output thereof. The interface level detection method is characterized in that the measurement of the measurement and the notification of the measurement are performed by controlling the measurement.