JP2001121142A - Scum removing apparatus for digester tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scum removing apparatus for a digester tank which is effective for removal and is inexpensive. SOLUTION: The scum removing apparatus for removing the scum floating in the tank to the outside has a leading-out means which makes a trough having a scum induction port liftable according to the fluctuation in a water level and introduces the scum induced into the trough to the outside of the tank.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scum removing device for removing scum generated in a digestion tank to the outside thereof.

[0002]

2. Description of the Related Art Sludge digestion refers to the decomposition and stabilization of organic substances contained in sludge by anaerobic reactions. One of the methods is an anaerobic digestion method. In this method, sludge is put into a digestion tank in which air is shut off, and the sludge is fermented in an anaerobic state while being stirred and mixed. 50 to 60% of organic components in the sludge are decomposed and the sludge properties are stabilized. .
A lot of methane gas and carbon dioxide gas are generated in the process,
Most of the generated methane gas is used as a supplementary fuel for heating digestion tanks and incinerators after removing (desulfurizing) a small amount of sulfur contained therein. Recently, power has been generated using this gas.

[0003]

The digestion tank has:
There are various shapes such as cylindrical, egg-shaped, and turtle-shaped, but in each case a large amount of scum accumulates on the water surface inside, and in the past there was no inexpensive device to effectively remove this .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and has as its object to provide an inexpensive scum removing device for digestion tanks, which is effective for removal.

[0005]

According to an aspect of the present invention, there is provided a scum removing apparatus for removing scum floating in a tank to the outside, comprising a scum inlet. It is characterized in that the trough can be raised and lowered in accordance with the fluctuation of the water level, and that the trough is provided with a deriving means for guiding the scum drawn into the trough to the outside of the tank.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 shows a general example of an egg-shaped digestion tank, which includes a tank body 1 made of watertight reinforced concrete (or a PC structure equivalent thereto). The main body 1 is supported by a direct foundation 2 that is a ring foundation or another foundation such as a caisson.

A stay 3 is provided at a lower portion in the tank body 1, and a communication pipe 4 having an upper and lower opening shape is vertically provided through the stay 3 so as to vertically pass through the center of the body. The top and bottom of the tank body 1 are parabolic portions 5 and 6, which collect digestive gas in the parabolic portion 5 at the top and extract it to the outside. A drive source 7 is mounted above the top parabolic portion 5, and a drive shaft 8 projects downward from the drive source 7 in a reversibly rotatable state, and a coaxial 8 is inserted into the communication pipe 4. I have. A reversible feed means such as a screw is provided in the communication pipe 4, and a downward flow is generated as shown by a solid arrow when the drive source 7 rotates in one direction, and an upward flow as shown by a broken line arrow when rotated in the other direction. Is caused to occur.

Since the top of the tank is conical and the liquid level is narrow, the scum generated on the liquid level 10 by the rising flow of the sludge stirring flow can be crushed. However, crushing is not effective by itself, and the scum grows. The scum remains even if it is crushed, and a dedicated scum removing device for efficiently processing these scum and removing the scum to the outside has been required. In addition, the liquid level 10 has a fluctuating property, and a countermeasure is necessary.

FIG. 2 shows an embodiment of the scum removing device. The scum removing device is intended for an existing digestion tank. Two or three (or any other number of points) vertically penetrating through holes 13. Each of the insertion holes 13 has an inner diameter through which a trough 20 described later passes.

A fixed pipe 15 is passed through the insertion hole 13 through a packing 14 and is detachably fixed to the tank top wall 12 through a mounting plate 16. An elevating pipe 18 is inserted into the fixed pipe 15 via guide rollers 17 so as to be able to move up and down. The trough 20 is attached to the lower end of the lifting pipe 18 and a suction pump 21 is provided.

The trough 20 has hemispheres arranged vertically and connected between them by connecting members 22. The trough 20 is fixed to the upper half trough 20 through the lifting pipe 18. 23 is a float, a fixed pipe 1
5. By lifting the lifting pipe 18 and the trough 20,
The capacity can be adjusted appropriately. That is,
This is because a portion of the connecting material 22 is a scum inlet 24, and it is necessary to adjust the space between the inlets 24 so as to correspond to the liquid level 10. The lifting pipe 18
Since the pipe 23 projects outside the tank, the weight of the pipe 18 may be adjusted so that the float 23 may be of a fixed buoyancy type. Reference numeral 25 in FIG. 2 denotes a scum recovery unit, which may then pass through a treatment tank for microorganisms.

As shown in FIG. 1, a scum outlet 27 is opened at a height corresponding to the liquid level 10 of the tank body 1.
The scum may be eliminated through the mouth 27.
In this case, a weir 28 that can be driven up and down is provided on the outer surface of the tank body 1.
However, the weir 28 may be provided with a float floating in the liquid surface 10. Alternatively, air or water may be blown in the tank to promote scum discharge. 29 is a microorganism treatment tank.

FIG. 3 shows another embodiment, in which a trough 31 has an inverted triangular pyramid-shaped hopper shape, and a V-notch-shaped scum inlet 32 is formed in an upper opening thereof. Trough 31
A stay 33 is provided on the upper side, and the elevating pipe 33 and the trough 3 are connected via the stay 33. still,
34 is a submersible pump, 35 is a float, and 36 is a weight. This embodiment can be configured in place of the lower part of the scum removing device as in the embodiment shown in FIG.

FIG. 4 shows another embodiment, and shows a scum removing apparatus mainly intended for a newly installed digestion tank. In the figure, a pair of fixed pipes 39 (one, three or four) may be vertically installed from the tank top wall 12,
.. Are vertically movable and communicate with a trough 41 provided horizontally below the elevating pipe 40. The trough 41 has a square gutter shape, but may have a round gutter shape.

At the upper end of the trough 41, a scum inducing port 42, which is a V-notch, is provided. . In this case, a pump may be used, but it may be caused to flow naturally by a siphon method. 43 is a float for following the water level. As shown by the phantom line, a hydraulic or electric cylinder 45 may be used as a driving unit, and the driving unit may be configured to be driven by a water control sensor 48 by a water level sensor 46 and a control unit 47 thereof. Good. 49 is a microorganism treatment tank. The trough may be made of plastic in each embodiment.

FIG. 5 shows another embodiment, which relates to a scum removing apparatus applicable to a new or existing digestion tank. The device is a parabolic part 5 of the tank body 1.
Then, a through hole 51 is drilled corresponding to the liquid surface 10, and a fixed pipe 53 is fixed in the hole 51 through a packing 52 in a penetrating manner.
An elevating pipe 54 is placed inside the tank of the pipe 53 with a bellows 55
It is connected by. A first screw 57 and a second screw 58 are connected to both pipes 53 and 54 via a joint 56. The tip of the elevating pipe 54 is a scum inlet 59, and 60 is a float for following the water level. The scum attraction port 59 can move up and down according to the water level as indicated by the arrow, and swallows the scum of the liquid surface 10 and is guided to the outside by the first and second screws 57 and 58.

FIG. 6 shows another embodiment. In this embodiment, a rotation support portion 61 is provided around a drive shaft 8 corresponding to the height of the parabolic portion 5 of the tank body 1 and one or more revolving blades 62 are attached. And can swing freely between the virtual line. When the drive shaft 8 rotates in one direction, the blade 62 becomes like a solid line, and when the drive shaft 8 rotates in the other direction, the blade 62 becomes like a virtual line. Thus, the scum is pushed in the outer diameter direction, and the scum is sucked out of the tank by the pump 64 installed at the pushed position. It should be noted that the screw conveyor 65 may be used to remove the oil from the tank as shown by the imaginary line, or a V-notch type trough may be used.

In addition to the above-described embodiments, the present invention can be applied to other types of digestion tanks such as the above-mentioned cylindrical shape and tortoiseshell shape. In addition, especially in newly constructed digestion tanks, a scum skimmer (a scum removal device main body) having an opening at the top of a pipe such as a cylinder is arranged on the liquid surface, and is rotatable back and forth around a horizontal axis. It may be configured to swallow. In this case, the main body can be moved up and down freely, but it is not limited to this. Further, a pipe may be inserted from the top wall so that the lower end of the pipe can be swallowed, and the pump may be suctioned from outside the tank. In this case, the pipe can be freely raised and lowered according to the water level.

[0019]

According to the present invention having the above-described structure, an apparatus for removing scum in a digestion tank which is effective for removal and which is inexpensive can be provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a digestion tank including an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a main part of the scum removing device showing one embodiment of the present invention.

FIG. 3 is a front view showing another embodiment.

FIG. 4 is a longitudinal sectional view showing another embodiment.

FIG. 5 is a cross-sectional view showing another embodiment.

FIG. 6 is a cross-sectional view showing another embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Tank body 10 ... Liquid level 15 ... Fixed pipe 18
... elevating pipe 20 ... trough 24 ... scum inlet 3
1 ... trough 32 ... scum inlet 33 ... lifting pipe
34 ... submersible pump 39 ... fixed pipe 40 ... elevating pipe 41 ... trough 45 ... cylinder 53 ... fixed pipe 54 ... elevating pipe 57, 58 ... screw 59 ...
Scum inlet 64 ... Pump 65 ... Screw conveyor.

Claims (1)

[Claims] 1. A scum removal device for removing scum floating in a tank to the outside, wherein a trough provided with a scum induction port can be moved up and down according to a change in water level. An apparatus for removing scum in a digestion tank, comprising a deriving means for guiding induced scum out of the tank.