JPH0133140Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an apparatus for filtering and concentrating a suspension such as sewage sludge.

[Conventional technology]

A screen drum having a cylindrical surface made of a liquid-permeable screen is rotatably installed in a filtrate receiving tank, and its rotational drive device is connected to the screen drum. When the suspension is supplied into the screen drum, the filtrate suspended in the screen is collected through the filtrate receiving tank, and the concentrated slurry is discharged from the other end of the screen drum. A suspension concentrating device designed to do this is known, for example, from Japanese Patent Publication No. 55-42819.

In the above-mentioned known example, the filtrate receiving tank is provided with an overflow port, and the filtrate filtered by the screen drum is
The filtrate is collected at a predetermined height in the filtrate tank, and filtration is performed with the lower part of the screen drum always partially immersed in the filtrate receiving tank.

[Problem that the invention attempts to solve]

In a suspension concentration device in which filtration is performed under the conditions described above, filtration by gravity is performed using the slight difference between the head of the suspension in the screen drum and the head of the filtrate in the filtrate receiving tank. Therefore, in order to obtain a large filtration pressure, the overflow port should be lowered or the filtrate should not accumulate in the filtrate receiving tank to prevent the screen drum from being immersed in the filtrate. good.

However, in this case, the sludge concentrated in the rotating screen drum strongly adheres to the inner surface of the screen drum.
Not only is it prone to clogging, but it is also difficult to separate from the screen. Additionally, as the drum rotates, the clumps of mud adhering to the inner surface of the screen are lifted up to a high position inside the drum, and when they collapse, they are thrown onto the inner surface of the screen below. Therefore, the impact at this time causes problems such as the mud passing through the screen and being pushed out of the drum.

The purpose of this invention is to provide a suspension concentration device that does not cause the above-mentioned problems even if the lower part of the screen drum is not immersed in the filtrate in the filtrate receiving tank.

In addition, in conventional suspension concentration devices using screen drums, the stock solution is supplied into the screen drum through an opening formed at one end of the screen drum. It is constructed so that the outlet part of the suspension is connected to the inserted suspension supply pipe,
In the conventional apparatus, the suspension supply pipe was opened downward below the axis of the screen drum.

Therefore, in conventional equipment, the lower part of the screen drum is always immersed in the filtrate receiving tank for one minute.
If the suspension is supplied from the supply pipe to the part of the screen drum that is immersed in the filtrate receiving tank, the suspension supplied to the screen drum will flow into the screen drum. This is not a problem because it is diffused and then filtered, but
In order to obtain a large filtration pressure, if the screen drum is prevented from being immersed in the filtrate by preventing the filtrate from accumulating in the filtration tank, the outlet of the suspension is aligned with the axis of the screen drum as described above. The conventional suspension supply device, which opens downward at the bottom of the suspension, has the following problems.

In other words, if the suspension supplied into the screen drum is filtered without accumulating in the screen drum, the suspension supplied into the screen drum will flow through the inner surface of the screen drum as the screen drum rotates. There was a problem in that the filtration action by the screen drum was only performed in a short rotational range (approximately 90 degrees) from just below the axis of the screen drum to the side thereof.

Another purpose of this invention is to solve the above-mentioned problem when the lower part of the screen drum is not immersed in the filtrate receiving tank, so that the filtration action can be performed more efficiently and over a longer rotation period of the screen drum. An object of the present invention is to provide a suspension concentrating device which is adapted to be used in a suspension concentration system.

[Means to solve the problem]

The technical means taken by this invention to solve the above problems is to install a screen drum whose cylindrical surface is made of a liquid-permeable screen so as to be rotatable in a filtrate receiving tank, and to attach the screen drum to the screen drum. A rotational drive device is connected to the screen drum, and a suspension supply device is disposed at one end of the screen drum, and the suspension is supplied into the screen drum.
A suspension concentrating device, wherein the filtrate filtered through a screen is collected through a filtrate receiving tank, and the concentrated slurry is discharged from the other end of the screen drum, wherein the screen drum A screen drum cleaning device capable of supplying cleaning water toward the rising side and surface of the screen drum is disposed at a position substantially along the axial direction of the screen drum on the side of the screen drum. The washing water of the washing device is supplied to a position on the rising side surface of the screen drum that is slightly higher than the center of rotation of the screen drum; comprising a suspension supply tube having its suspension outlet portion inserted into the screen drum through an opening formed at one end of the screen drum; In the vicinity of the opening, the shape of the outlet portion in plan view is formed into a U-shape, and the outlet portion is piped horizontally or with a slight upward slope, and the outlet is located near the screen. ,It is in.

〔Example〕

To explain the embodiment with reference to FIGS. 1 to 8, 2 is a filtrate receiving tank supported by the machine frame 1, 3 is a sludge receiving tank installed next to the filtrate receiving tank 2 with a partition wall 4 in between. 2 is connected to a filtrate extraction pipe 5, and the sludge receiving tank 3 is provided with a discharge chute 6. A screen drum 10 as described below is horizontally suspended within the filtrate receiving tank 2.

That is, this screen drum 10 includes a pair of annular end plates 11, 12 and several annular bones 13, 13...
A screen 15 like a filter cloth is stretched around the circumferential surface of a cylindrical case formed by connecting the 4, 14, etc., and this screen drum 10
A support arm 1 is provided on a rotating shaft 16 passing through the center thereof and protrudes in a radial direction from the rotating shaft 16.
7, 17, etc., and by supporting this rotating shaft 16 on a pair of bearings 18, 18 on the machine frame 1, the axial direction thereof is slightly inclined. , horizontally suspended in the filtrate receiving tank 2. Note that 19 and 20 are ribs of the support arm 17;
Reference numeral 1 denotes a sprocket wheel fitted onto the rotating shaft 16, and the screen drum 10 is connected to its drive source (not shown) via the sprocket wheel 21 and chain 22.

The configuration described above is the same as that seen in conventionally known concentrating devices, but the concentrating device according to this invention includes the following cleaning device located on the side of the screen drum 10. 25 are arranged.

That is, reference numerals 26 and 26 denote a pair of support columns erected from the machine frame 1, and the support columns 26 and 26 are provided with a surface on the rising side when the screen drum 10 rotates, which are arranged along the axial direction of the screen drum 10. The cleaning water can be spouted toward a position slightly higher than the rotating shaft 16. Many knots 2
A cleaning water supply pipe 28 with pipes 7, 27, . . . attached thereto is installed.

Further, reference numeral 30 denotes an outlet portion 3 of the suspension from the opening 11a of the end plate 11 constituting the screen drum 10 into the screen drum 10.
0a is inserted into the suspension supply pipe 30, and as shown in FIG. The outlet portion 30a has a U-shape in plan view, and the outlet portion 30a is piped horizontally or with a slight upward slope, and the outlet is located near the screen.

[Effect of action]

The suspension concentration device of this invention is provided with a cleaning device at a position along the axis of the screen drum on the side of the screen drum. of,
Washing water can be supplied to a position slightly higher than the center of rotation of the screen drum, so when this washing device is activated,
When the screen drum is rotated and the suspension is concentrated, the sludge adhering to the inner surface of the screen drum is removed as the screen drum rotates.
On the way up, the washing water that passes through the screen and is supplied into the screen drum allows the screen to be separated from the screen reliably and smoothly without any falling impact.

Therefore, the above-mentioned washing device has the effect of being able to separate the mud from the screen efficiently even with a weak washing water pressure, and because the washing pressure is low, it can separate the mud from the screen without destroying the flocs of the mud. It has the effect of being able to concentrate, and since the muddy material is separated without any impact from falling, the muddy material will not be slammed against the screen and fall through the screen. can.

In addition, although the concentrating device of this invention is equipped with the above-mentioned washing device, there is also a device inside the screen drum for receiving the washing water and discharging it outside the screen drum. Since there is no water collection device installed, you may be concerned that the concentration level will decrease with this device, but when we tested it, we found no decrease in the concentration level at all. On the contrary, the effect is that the recovery rate of suspended solids is good because the washing water containing mud does not come out of the system, and in the case of mud that has aggregated with polymers, the washing water In this case, the polymer remaining on the surface of the slurry was washed away, resulting in an improved concentration effect. This idea was made based on such knowledge.

In addition, in the suspension concentrating device of this invention, the suspension is supplied into the screen drum, especially in the vicinity of the opening of the screen drum, where the outlet portion is formed into a U-shape in plan view. At the same time, the outlet section is piped horizontally or with a slight upward slope, and the outlet is connected to a suspension supply pipe located near the screen.
The suspension supplied from the outlet of the supply pipe into the screen drum reaches a position approximately symmetrical to the area to which the cleaning water is applied when the axis of the screen drum is the center of the object. The liquid is supplied toward the inner circumferential surface of the screen drum, and is biased in a counter direction with respect to the rotational direction of the screen drum.

Therefore, with the device of this invention, a large filtration pressure can be obtained at this time, and the suspension supplied into the screen drum has a longer filtration section (more than 90 degrees) compared to the conventional device described above. According to the concentrating device of this invention, the suspension supplied into the screen drum is filtered in the above-mentioned first half filtration section immediately after being supplied into the screen drum to avoid the influence of the washing liquid. In the subsequent filtration section, the slurry that has been dehydrated and has a high concentration can be filtered while being washed with washing water, and the suspension supplied to the screen drum can be filtered as a whole. It can be concentrated extremely efficiently.

[Brief explanation of the drawing]

FIG. 1 is a partially longitudinal side view showing an embodiment of a suspension concentrating device according to this invention, and FIG.
3 is a sectional view taken along the line 1-2, and FIG. 3 is a plan view of the suspension supply pipe. 2...Filtrate receiving tank, 3...Sludge receiving tank, 10...
Screen drum, 15...filter cloth (screen),
16... Rotating shaft, 25... Washing device, 27... Nozzle, 28... Washing water pipe, 30... Suspension liquid supply pipe.

Claims (1)

[Claims for Utility Model Registration] A screen drum having a cylindrical surface made of a liquid-permeable screen is rotatably installed in a filtrate receiving tank, and a rotation drive device for the screen drum is connected to the screen drum. A suspension supply device is installed at one end of the drum, and when the suspension is supplied into the screen drum, the filtrate filtered through the screen is collected through the filtrate receiving tank, and the concentrated sludge is collected. is discharged from the other end of the screen drum. A cleaning device for the screen drum that can supply cleaning water toward the side and surface of the screen drum is installed, and the cleaning water from the cleaning device is supplied from the center of rotation of the screen drum on the rising side surface of the screen drum. the suspension is supplied to a slightly higher position; The suspension supply pipe has a part inserted into the suspension supply pipe, and the exit part of the suspension supply pipe has a U-shape in plan view near the opening of the screen drum. A suspension concentrating device characterized in that the outlet portion is piped horizontally or with a slight upward slope, and the outlet is located near a screen.