JPS5861809A - Detector for flocculated floc - Google Patents

Abstract

PURPOSE:To provide a detector for flocs which permits continuous measurement automatically for a long time and lessens manpower by providing a transparent plate and a photodetecting plate. CONSTITUTION:In figure, 1 is a transparent glass cylinder in a vertical direction where flocculated waste water flows from below to above. A linear projector 2 is provided in a vertical direction along the outside surface of the cylinder 1. A photodetector 3 is attached on the outside surface on the other side of the cylinder 1 by facing the projector 2 so that the light projected from the projector 2 passes through the flocculated waste water flowing in the cylinder 1 and is detected with an image sensor. A cover 4 is provided to enclose a part of the projector 2, the photodetector 3 and the cylinder 1 so as to prevent the entry of miscellaneous light from the outside into the photodetector 3. An annular fresh water chamber 5 is provided between the bottom end of the cylinder 1 and the constricting part 9 of an inflow part 11 so as to enclose both. The average grain sizes of flocculated flocs are detected automatically by making use of the change in transmittance with the varying sizes of the flocs.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for detecting agglomerated flocs such as an aggregation mixing tank.

For example, in a coagulation mixing tank in wastewater treatment equipment, solid-liquid separation has traditionally been promoted by adding a coagulant to wastewater to generate coagulated flocs. It is desirable to continuously adjust the amount of addition to an appropriate value, but since a suitable means for detecting flocs has not been developed, currently, the separation clarity after wastewater treatment is measured, and the moisture value in the separated solid content is measured. The amount of flocculant added is determined each time by measuring the amount of flocculant or using a turbidity meter.

The present invention was proposed in view of the above circumstances, and aims to provide a labor-saving coagulated floc detection device that can automatically carry out continuous measurement over a long period of time. a transparent plate, one of a light emitter or a light receiver attached to the other surface of the transparent plate, and a light emitter or a light receiver attached to one surface of the transparent plate at an appropriate interval and opposite to one of the light emitter or light receiver. The present invention is characterized in that it comprises a cleaning means for cleaning the other of the projector and the receiver, and the surface of the transparent plate that is immersed in the coagulated wastewater.

Embodiments of the present invention will be explained with reference to the drawings. FIG. 1 is a vertical cross-sectional view showing a first embodiment in which the present invention is applied to the outlet piping of a flocculation mixing tank, and FIG. FIG. 3 is a longitudinal cross-sectional view showing a second embodiment in which the present invention is applied to an outlet gutter of a coagulation mixing tank.

First, in Fig. 1, 1 is a transparent glass tube in the vertical direction through which the coagulated wastewater flows from the bottom to the top, and 2 is a transparent glass tube l.
A linear light projector 3 installed vertically along the outer surface of the projector 2 is attached to the outer surface of the other side of the transparent glass tube l, facing the projector 2, and allows the light emitted from the projector 2 to flow through the transparent glass tube l. An image sensor that receives light through the coagulated wastewater - a multiple light receiver, 4 a light emitter 2 degrees and a light receiver 3. This is an annular cover that surrounds a part of the transparent glass tube l to prevent miscellaneous light from outside from entering the light receiver 3, and the cover 4 surrounds the entire transparent glass tube l to enable visual observation of the coagulated wastewater. 5 is an annular fresh water chamber attached between the lower end of the transparent glass cylinder 1 and the narrowed part 9 of the coagulated wastewater inflow pipe 11 so as to surround both, and a fresh water inlet 10 as described later. The introduced fresh water flows out from the annular gap 8 between the lower end of the transparent glass cylinder l and the narrowing part 9, forming a fresh water film along the inner surface of the transparent glass cylinder 1. 6 is the upper end of the transparent glass cylinder l. A flange connecting the flanges to the lower end of the coagulating wastewater outflow pipe 12, 37F! .

There are seven flanges connecting the upper end of the coagulated wastewater inflow pipe 11 to the lower end of the narrowed part 9.

In such a device, the transmittance of light passing through the flocculated wastewater in the transparent glass tube 1 varies widely depending on the size of the flocs, and the transmittance of the culm base where the flocs are large increases. Become.

For example, approximately 19 flocs with an average particle size of 10 mm have a total volume of 10 cIl, and when they are arranged on a plane, the total shadow area is approximately 14.9 d, whereas the flocs with an average particle size of lμ have a total volume of 10 cIl. In the case of 1.9 x 10" pieces, the total volume is 10
i, the total projected area is 1.5x10'i, so the latter has a total projected area about 10,000 times larger than the former, so the light transmittance is large due to the size of the aggregated flocs. Fig. 2 shows this relationship in terms of projected area ratio for the particle size range of agglomerated flocs lμ to 22 mm, with the average particle size of 10++ m set as 1. Well, you can find out the average particle size of the flocs.

Therefore, in FIG. 1, the amount of light entering the receiver 3 changes depending on the size of the agglomerated flocs in the transparent glass tube l, and the light receiver 3 has a large number of diodes having image sensors arranged in parallel as light receiving elements, and a multiplexer. The brightness and darkness of the light in the field of view is scanned and output sequentially by the photodiode 1.
It is possible to read the light and shade of each individual floc and determine the size of the flocs.

In some cases, a pendency meter can also be used as a light receiver.

At this time, if the inner surface of the transparent glass tube l becomes contaminated with coagulated wastewater, the proper functioning of the light projector 2 and the light receiver 3 will be inhibited.

Therefore, fresh water is always introduced into the fresh water chamber 5 through the fresh water inlet 10 and passed through the annular gap 8 into the transparent glass tube 1.
By flowing into the transparent glass tube 1 and forming a fresh water film on the inner surface of the transparent glass tube 1, the coagulated wastewater is prevented from directly contaminating the inner surface of the transparent glass tube 1. Therefore, the flow rate of the fresh water membrane is slightly higher than that of the flocculated wastewater. Allow the flow to flow at a high speed.

In this way, it is also possible to prevent the coagulated wastewater from flowing back into the fresh water chamber 5 through the annular gap 8. At this time, if air bubbles get mixed into the water film, the function of the light receiver 3 will be inhibited, so it is necessary to prevent the bubbles from getting mixed in. The cross-sectional shape of the transparent glass cylinder is appropriately selected, such as a circle or a square. The fresh water film does not need to be provided over the entire circumference of the transparent glass tube 1, but may be provided on the inner surface of the transparent glass tube 1 facing the projector 2 and the light receiver 3, respectively. Furthermore, a wiper or the like may be attached instead of or in combination with the clean water membrane to mechanically clean the inner surface of the transparent glass cylinder.

Next, in the second embodiment shown in FIG. 3, the present invention is applied to the part where the coagulated wastewater flows into the gutter from the coagulation mixing tank to the separator by using the head difference, and 21 is the coagulated wastewater inlet. ,2
2 is a flocculant, 23 is a coagulation mixing tank, 24 is a stirrer, and 25 is formed between the upper end of a transparent glass plate 27 stretched upstream of the gutter 26 and the bath outlet slope of the coagulation mixing tank 23, surface 23'. 28 is a fresh water inlet, 28' is a fresh water chamber, and the upper end of the transparent glass plate 27 and the bath outlet slope 23'
It is attached at the bottom between. 29 is transparent glass plate 2
A linear floodlight is attached above 7 and extends parallel to the direction of inclination of the transparent glass plate 27.

A light receiver 30 is attached below the transparent glass plate 27 and receives the light from the projector 29 through the transparent glass plate 27;
1 is a mist hood that shields the projector 29 from water droplets and external light; 32 is a sealing cover that shields the light receiver 30 from external light; and 33 is an air inlet that introduces pressurized air into the mist hood 31.

In such a device, when the coagulated wastewater discharged from the coagulation mixing tank 23 passes through the bath outlet slope 23' and the transparent glass plate 27 to form a plate-shaped water stream and flows into the gutter 26, the fresh water inlet 2
8, the fresh water introduced into the fresh water chamber 28' is made to flow along the upper surface of the transparent glass plate 27 at a flow rate of about 1 to 5 times the flow rate of the coagulated wastewater, forming a water film through the linear gap 25. This prevents the coagulated wastewater from directly touching the transparent glass plate 27 and contaminating it, and the size of the coagulated flocs can be detected in the same manner as in the first embodiment.

At that time, if necessary, compressed air is introduced from the air supply 33 to suppress the generation of mist.

In the first and second embodiments described above, the particle size of the flocculated flocs in the flocculated wastewater can be determined from the output of the light receiver, so that the flocculation can be carried out by adding an appropriate amount of flocculant according to the particle size. Even if the particle size of the flocs is maintained at an optimum value, solid content in wastewater can be separated with high efficiency.

In short, according to the present invention, at least one surface is immersed in coagulated wastewater, a transparent plate, one of a light projector or a light receiver attached to the other surface of the transparent plate, and a By providing the other of the emitter or receiver attached at a distance from one of the emitter or receiver, and a cleaning means for cleaning the surface of the transparent plate that is immersed in the coagulated wastewater, The present invention is industrially extremely useful because it provides a labor-saving floc detection device that stably detects flocs in automatically collected wastewater.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the first embodiment of the present invention, FIG. 2 is a chart showing the relationship between the particle size and projected area of the agglomerated flocs in FIG. 1, and FIG. 3 is a diagram showing the second embodiment of the present invention. It is a longitudinal cross-sectional view showing an example. 1. Transparent glass tube, 2. Emitter, 3. Receiver, 4
・・Cover, 5・・Fresh water chamber, 6° 7・・・7 langes, 8・・Annular gap, 9・・Narrowing part, 10・・Fresh water inlet, 11・・Coagulation wastewater inflow pipe, 12・・・Coagulation wastewater outflow pipe,
21: Coagulation wastewater inlet, 22: Coagulant, 23: Coagulation mixing tank. 23'... Bath exit slope, 24... Stirrer, 25... Linear gap, 26... Gutter, 27... Glass plate, 28... Fresh water inlet, 28'... Fresh water chamber, 29... Floodlight. 30・
・Receiver, 31...Miss, hood, 32...Airtight cover, 33...Air inlet, Agent: Patent attorney Tadashi Tsukamoto Bunshuza Fudo 2 Zutoshi 3 Kuniyasu

Claims (1)

[Claims] A transparent plate having at least one surface immersed in the coagulated wastewater, one of a light projector or a light receiver attached to the other surface of the transparent board, and one surface of the transparent board with an appropriate distance between the light projector and the light projector. Alternatively, an agglomerated floc detection device comprising: the other of the light emitter or the light receiver attached to face one of the light receivers; and a cleaning means for cleaning the surface of the transparent plate that is immersed in the agglomerated wastewater.