JPS6018474B2 - flotation separation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus that performs flotation separation by generating fine bubbles using a water head difference.

First, the conventional apparatus will be explained with reference to FIG. 1. Reference numeral 1 is an air ration tank, 2 is a floatation tank, and both are passed through a lower lotus passage 3.

Further, there is an air diffuser 4 connected to a compressed air source at the lower part of the tank 1, the lower part a of the tank is a small straw, and the upper part b is enlarged and a scum scraper 5 is installed at its upper end. This scraping machine 5
This is a pair of left and right endless chains with a large number of flights lined up at regular intervals, and an overflow trough 6 is provided to discharge the floating scum scraped up by the scraper 5. In the case of such a conventional device, water to be treated (hereinafter referred to as raw water) mixed with a flocculant etc. flows from the upper part of the aeration tank 1, enters the tank 2 through the lotus passage 3 at the lower part, and enters the overflow trough 6. The water overflows to the outlet pipe 10 and is taken out from the take-out pipe 10. Further, the air ejected from the many air diffusers of the air diffuser 4 mixes into the raw water in the tank 1 as bubbles, and some of the air bubbles are dissolved in the raw water. Therefore, the raw water flowing into the lower part a of the flotation tank 2 from the lotus passage 3 becomes under reduced pressure as it rises into the tank 2, so dissolved air becomes fine bubbles and precipitates, adsorbed by suspended substances in the raw water. and surface. The floating scum is discharged to an overflow trough 6 by a scraper 5, and the treated water from which the scum has been separated is taken out from a treated water outlet pipe 7 provided in the middle of the tank 2. However, in the case of a follower device like the one above,
When warming air with the air diffuser 4 at the bottom of the aeration tank 1, an air lift effect occurs due to excess air, causing turbulent flow within the tank 1, and the liquid at the top and bottom of the tank 1 mix, so the air at the bottom of the tank Solubility decreases. The purpose of the present invention is to prevent the deterioration of the air dissolution efficiency in the aeration tank in the conventional device as described above, and as shown in FIG. Alternatively, a plurality of porous baffle plates 8 such as a net shape are arranged at appropriate intervals, and if necessary, a plurality of balls 9 are arranged below each baffle plate 8, and the balls 9 are made of plastic. etc., baffle plate 8
The liquid must be of such a size that it cannot pass through the hole in the shaft, and its specific gravity is lower than that of the liquid in the shaft.

Further, since the other structures are the same as the conventional device shown in FIG. 1, the same reference numerals are given and the explanation will be omitted.
Since the present invention provides the porous baffle plate in the aeration tank as described above, the airlift effect caused by the air released from the air diffuser 4 is reduced.

Therefore, mixing of the liquid between the upper and lower parts in the aeration tank is prevented, and the air dissolution efficiency can be improved compared to the conventional one. Next, the difference between the conventional layer and the device of the present invention will be explained using graphs shown in FIGS. 3 and 4.

In each figure, the vertical axis shows water depth, and the horizontal axis shows dissolved oxygen concentration. In both graphs, the diagonal line A represents the theoretical oxygen solubility with respect to water depth. However, in the conventional apparatus shown in FIG. 3, the actual dissolved oxygen concentration is as shown by the solid line B, and bubbles are deposited at the water depth indicated by the dotted line C.

In addition, in the case of the device of the present invention shown in FIG. 4, the oxygen concentration changes in different stages as shown by the solid line D, but on average it almost matches the diagonal line A, and the oxygen dissolution efficiency is higher than that in FIG. 3. I understand that. Moreover, in the graph of FIG. 3, dotted line B is the water depth at which bubbles are deposited. As described above, the present invention improves the dissolution efficiency of air with an extremely simple structure of simply providing a porous baffle plate in the aeration tank of the conventional device, thereby increasing the flotation separation efficiency of suspended matter in the flotation tank. This has the effect of increasing

In addition, when the spheres are arranged as in the embodiment, the spheres flow due to the downward flow in the aeration tank and the rising surplus air, which not only increases the mass transfer efficiency. It is possible to reduce the airlift effect caused by excess air and further enhance the effect of preventing liquid from flowing between the upper and lower portions within the aeration tank.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal side view of a conventional flotation device, FIG. 2 is a longitudinal side view of a flotation device of the present invention, and FIG. 3 is a graph showing the water depth and oxygen concentration in the aeration tank of the conventional device. FIG. 4 is a graph showing the water depth and oxygen concentration in the aeration tank of the device of the present invention. 1... Air ration tank, 2... Floatation tank, 3... Communication path, 4... Air diffuser, 8... Baffle plate, 9... ···ball. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. An air ration tank is provided adjacent to the floatation tank, the floatation tank and the air ration tank are communicated at the bottom, and an air diffuser is provided at the bottom of the air ration tank. What is claimed is: 1. A flotation separation device for flotation and separation using a water head difference, characterized in that a plurality of grid or net-shaped baffles are arranged at appropriate intervals in the air ration tank. 2. In the flotation separation device set forth in claim 1, a plurality of spheres are arranged below each baffle plate in the air ration tank, the size of which does not pass through the baffle plate, and the specific gravity of which is smaller than the water to be treated. thing.