JPS58156359A - Bowl-type centrifugal precipitation separator - Google Patents

Abstract

PURPOSE:To suck up and drain conc. sludge without the provision of a conical part at a bowl, by providing a draining vessel which rotates in proportion to a difference between the rotation speeds of the bowl and a screw conveyer. CONSTITUTION:A plurality of collecting vessels 11 are provided inside a chamber for conc. sludge, an opening 14 for sucking up sludge is bored at the top end part of the side wall of each of the vessels 11, and the vessels 11 are rotated in proportion to a difference between the rotation speeds of a bowl 1 and a screw conveyer. Transferred conc. sludge is intermittently sucked up by the openings 14 for sucking up sludge and drained outside the bowl 1. Accordingly, conc. sludge having the desired concentration of solid matter is drained regardless of the fluctuation in the concentration of solid matter in a supplied liquid and the amount of the supplied liquid without the need to provide a conical part at the bowl.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bowl-type centrifugal separator, and more particularly to a horizontal-shaft bowl-type centrifugal separator having a screw conveyor.

The water tank type centrifugal sedimentation separator supplies slurry into the bowl of a cylindrical or conical high-speed rotating body, and uses centrifugal force to settle the solids toward the peripheral wall of the bowl, converting them into solids and clear liquid or concentrating them. It separates into sludge and diluted slurry. There are two types of bowl-type centrifugal separators: vertical shaft type and horizontal shaft type. The former is said to be suitable for treating slurry with a low solids concentration. The latter can handle relatively thick materials, and generally the solids settled on the peripheral wall of the bowl are transferred to one end of the bowl by a screw conveyor and discharged.

To discharge solids or thickened sludge in this type of centrifugal sedimentation separator, part or all of the bowl is conical, and a screw conveyor transfers the solids or thickened sludge to the small diameter part of the conical part. There is a method in which the bowl is cylindrical and the solids or thickened sludge transferred by a screw conveyor is discharged through a nozzle provided at the side end of the bowl. Foreskin is an effective method for obtaining well-dewatered sludge and has become the standard thickened sludge discharge method in this type of centrifugal sedimentation separator.

However, by the former method, for example, solids concentration 1
This method is not necessarily suitable when simply concentrating sludge, such as when concentrating sludge with a solid content of less than 50 mL and supplying it to a digestion tank.

In other words, in such a case, it is necessary to operate with the liquid level of the pool in the cone close to the concentrated liquid discharge hole at the end of the cone, and the dry beach must be almost zero, but this kind of operation is generally not carried out. Under certain conditions, it is often impossible to obtain a stable concentrated concentration.

In addition, with this method, the angle between the conical surface of the bowl and the shaft must be made small, so the length of the conical part becomes longer.
There is a drawback that the length of the liver-kidney sedimentation separation section, that is, the cylindrical section, is not sufficient.

On the other hand, in the latter discharge method using a nozzle, when the solids concentration of the feed liquid is low, the trap must throttle the discharge amount of thickened sludge in order to maintain the thickened sludge at a predetermined concentration (
i.e. a small-bore nozzle must be used), and therefore,
There is always a risk of nozzle blockage.Furthermore, if there are large fluctuations in the amount of liquid supplied or the concentration of solids, the machine must be stopped and the nozzle replaced each time to accommodate this. In terms of power consumption, the former method discharges sludge with a lower kinetic energy than the small diameter part at the conical end because the sludge in the large diameter part of the bowl that has high kinetic energy is discharged as is. Comparatively, it always shows high values.

An object of the present invention is to be able to discharge thickened sludge with a desired solids concentration without providing a conical part in the bowl and regardless of fluctuations in the solids concentration of the feed liquid and the supply amount, and to reduce the overall length of the bowl. To provide a bowl-type centrifugal sedimentation separator that does not need to be large in size and can concentrate sludge with power equal to or less than that of a device having a conical part in the sieve.

According to the present invention, a cylindrical bowl that rotates about a horizontal axis and a cylindrical bowl that rotates about a horizontal axis, and a cylindrical bowl that rotates in the vicinity of its inner circumferential wall within the electric bowl, are arranged at an adjustable rotational speed difference between the bowl and the bowl. ,
It is equipped with a screw conveyor that rotates coaxially with the shaft, and the above-mentioned screw conveyor is provided from the direction of the rotation axis. The solids in the sludge supplied into the sludge are sedimented and separated on the inner wall of the bowl by centrifugal force, and the separated solids or thickened sludge is transferred to one side end of the sludge by a screw conveyor, The clarified liquid is discharged to the outside of the bowl by a discharge means provided in the bowl, and the clarified liquid is discharged overflowing from the side wall of the bowl. One or more pumping containers that rotate in proportion to the difference in rotational speed of the screw conveyor, and a pumping port formed in the container intermittently drains the thickened sludge area near the peripheral wall of the bowl due to the rotation of the containers. The container enters the container and pumps out the thickened sludge, and the discharge port drilled in the container is constantly or intermittently aligned with the opening in the side wall of the bowl, so that the pumped thickened sludge is discharged out of the bowl. There is something about it.

In a preferred embodiment of the wheel-type centrifugal sedimentation separator according to the present invention, two to four of the above-mentioned scooping containers are provided, each of which is arranged at equal intervals surrounding the rotating shaft of the screw conveyor, parallel to the shaft, and connected by gears. The driven shafts are mounted on the same number of driven shafts, and the driven shafts are hollow shafts that extend outside the bowl through the side wall of the bowl, and the hollow shafts form the discharge ports for the thickened sludge.

Embodiments of the present invention will be described below based on the drawings. 1st
2 and 2 are a schematic vertical cross-sectional view of an embodiment of the bowl-type centrifugal sedimentation separator of the present invention, and a schematic cross-sectional view taken along the Mu staff line in FIG. 1. In addition, although the embodiment shows an apparatus for sludge concentration, the name is different (sludge and sludge), and general slurry concentration can be carried out in exactly the same way.

This device includes a cylindrical bowl 1 and a screw conveyor 2 provided within the bowl 1 close to the inner circumferential wall of the bowl 1.
It is equipped with The bowl 1 is fixed to a horizontal hollow shaft supported by a bearing 3. The hollow shaft is rotated at high speed by a drive source (not shown). The screw conveyor 2 is fixed at both ends to rotating shafts 6A and 6B which are concentric with the hollow shaft of the bowl 1, inserted into the hollow shaft, and rotatably supported by the hollow shaft, and are connected to a drive source or a drive source (not shown). The bowl 1 is rotated in the same direction as the bowl 1 by a transmission means from the bowl rotation shaft, with an adjustable rotation speed difference from the rotation speed of the bowl 1.

The cell 1 is partitioned by a separation disk 8 into a sedimentation separation chamber 4 on the left side of the drawing and a thickened sludge chamber 5 on the right side. The sedimentation separation chamber 4 and the thickened sludge chamber 5 communicate with each other at the peripheral edge of the separation disk 8, that is, near the peripheral wall of the bowl 1. A portion of the screw of the screw conveyor 2 exists only in the sedimentation separation chamber 4.

The shaft 5B on the left side in the drawing of the screw conveyor 2 is a hollow shaft, into which a supply pipe 6 for sludge to be supplied is inserted. The supplied sludge enters the screw conveyor 2 from the supply liquid source 17 through the supply pipe 6 and is sent to the sedimentation separation chamber 4 from the liquid distribution boat 7. Six ducts 10 extending through the thickened sludge chamber 5 and out of the bowl 1 are joined to the separation disk 8 at equal intervals.

In addition, a duct 1 is provided on the sedimentation separation chamber 4 side of the separation disk 8.
An annular groove 9 for collecting separated liquid is provided to cover the opening of 0. When the bowl 1 rotates at high speed, the sludge in the sedimentation separation chamber 4 is pressed against the peripheral wall of the bowl 1 by centrifugal force, and when the liquid level approaches the edge of the annular groove 9, the liquid flows from the edge to t4.
It overflows into the annular groove 9, passes through the duct 10 from the annular groove 9, and is discharged to the outside of the bowl 18. 16 is the pool liquid level.

The thickened sludge chamber 5 is provided with five pumping containers 11. The scooping containers 11 surround the rotating shaft 6m of the screw conveyor 2, are provided at equal intervals, are parallel to the shaft 6m, and are respectively attached to six driven shafts 12 connected to the shaft 6m by a gear mechanism 15. , is bearing on the separation disc 8 of the meckle 1. A hollow shaft 13 coaxial with the driven shaft 12 is fixed on the opposite side of the driven shaft 12 that fixes the pumping container 11.
3 passes through the side wall of the bowl 1 and is rotatably supported in a sealed manner by the side wall.

As is clear from FIG. 2, the collecting container 11 has a shaft 12.1.
It has a fan-shaped cylindrical shape with center point 3, and a pumping port 14 for pumping out the thickened sludge is bored at the tip of its side wall (the side wall of the WI-shaped radius part). The thickened sludge separated from the clarified liquid in the sedimentation separation chamber 4 passes through the outside of the peripheral edge of the separation disk 8 and enters the thickened sludge chamber S. In FIG. 2, the peripheral edge of the separation disk 8 is shown in solid lines and is designated by the reference numeral 8. The pumping container 11 rotates as shown by the arrow, and the pumping port 14 intermittently enters the thickened sludge section as the pumping container 11 rotates, and pumps the thickened sludge into the container 11. The thickened sludge pumped into container 11 is
1 is moved to a position approaching the shaft 12.13, and is discharged through the hollow shaft 13 to the outside of the bowl 19.

The apparatus of the present invention is constructed as described above, and the supply liquid is supplied from the supply source 1.
7 through the supply pipe 6, and sent from the liquid distribution boat 7 to the sedimentation separation chamber 4. The feed liquid is separated into solid and liquid by centrifugal force in the sedimentation separation chamber 4, and the clarified liquid is passed through the annular groove 9 and the duct 1.
0 and is discharged to the outside of the bowl 18. Further, the solid matter or thickened sludge that has settled on the peripheral wall of the bowl 1 due to centrifugal force is transferred by the screw conveyor 2, passes through the gap around the periphery of the separation disk 8, enters the thickened sludge chamber 5, is scooped up into the scooping container 11, and is pumped up into the hollow shaft 13. It passes through and is discharged to the outside of the bowl 19.

The means for discharging the thickened sludge in this device is not always open like a conventional discharge nozzle, but the pumping port enters the thickened sludge intermittently to pump out the thickened sludge. The discharge passage to the outside of the mouth and bowl can be made sufficiently large, and there is no risk of blockage. In addition, the amount of thickened sludge discharged is exactly proportional to the rotational speed of the scooping container and therefore the rotational speed difference between the bowl and screw conveyor, so if there are fluctuations in the supply liquid conditions, the rotational speed difference can be adjusted while the operation is in progress. This allows us to respond quickly. Furthermore, it is also possible to construct a so-called automatic control system that continuously detects the concentration of thickened sludge or the amount of supplied liquid and its concentration, and controls the difference in rotational speed between the bowl and the screw conveyor based on the detected concentration. Note that the rotational speed difference can be precisely adjusted by the amount of oil in the case of hydraulic motor drive, or by a variable speed electric motor or continuously variable transmission in the case of gear mechanism drive. Furthermore, since this thickened sludge discharge means can be accommodated in a small space, by placing it on the edge of the bowl, almost the entire length of the bowl can be used as a sedimentation separation chamber. Furthermore, since the concentrated sludge discharge hole is located above the pool liquid level, it is expected that the power consumption will be the same or lower than that of the conventional homol conical end discharge method.

The shape of the scooping container in the apparatus of the present invention is not limited to the shape shown in the examples. For example, a cylindrical container is provided with one or more sets of partitions and a sludge intake port, and is fixed to a bowl and around a hollow penetrating shaft with a cutout hole provided in the interior of the container.
The container may be rotated. Furthermore, the discharge route for the pumped sludge does not necessarily have to pass through the hollow shaft. For example, when the side surface of a cylindrical collecting container and the inner surface of the Mekuru side wall are slid closely together, and holes are opened at appropriate positions on both sides, and the holes match,
The collected sludge may be discharged through the hole.

Next, an example of operation of the apparatus of the present invention will be described. Table 1 shows the specifications of each part of the apparatus according to the embodiment of the present invention. The code in the table is the first
The relevant parts described in Figures and 2 are shown.

Table 1 Part of the operational data when surplus activated sludge was concentrated using this device is shown in Table 2.

Table 2 As is clear from Table 2, the concentration fluctuations of the supplied sludge (0,
5 to 1.5%) is completely absorbed by adjusting the rotational speed difference between the bowl and screen pair (4.5 to 15.Orpm). Furthermore, fluctuations in the amount of supplied sludge could be absorbed in the same way, and concentrated sludge with a constant solids concentration could be obtained.

Furthermore, during operation of this apparatus, no obstruction 2 in the thickened sludge discharge path was observed to be in a state of poor circulation.

As described above, the apparatus of the present invention is capable of smoothly discharging the feed liquid as a thickened slurry with a desired solid concentration, regardless of fluctuations in the solid concentration and supply amount of the feed liquid, and the apparatus is also compact and consumes less power. Since the amount of water is small, it is extremely effective when used for concentrating sludge to be sent to a digestion tank.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional view of an embodiment of the bowl-type centrifugal separator of the present invention, and FIG. 2 is a schematic cross-sectional view taken along the line A--A in FIG. 1...bowl, 2...screw conveyor, 4...
・Sedimentation separation chamber, 5...Thickened sludge room, 6...Liquid supply pipe,
6 A e6B...Screw conveyor shaft, 7...
Liquid distribution hoard, 8... Separation disk, 11... Sumpling container, 12.13... Driven shaft, 14... Sumpling port, 15
...Gear mechanism, 17 agents, Asamura Kogai, 4 people

Claims (2)

[Claims] (1) A cylindrical bowl that rotates about a horizontal axis, and a screw conveyor that rotates coaxially with the bowl with an adjustable rotational speed difference within the bowl and adjacent to its inner circumferential wall. The solids in the sludge supplied into the basin from the direction of the rotating shaft are sedimented and separated on the inner wall of the bowl by centrifugal force, and the separated solids or thickened sludge is transferred to one side end of the bowl by a screw conveyor. In the bowl type centrifugal sedimentation separator, the clarified liquid is transferred to the bowl and discharged to the outside of the bowl by a discharge means provided at the side end, and the clarified liquid is discharged overflowing from the side wall of the bowl. One or more pumping containers rotate in proportion to the difference in rotational speed between the containers, and the pumping port formed in the container intermittently enters the thickened sludge area near the surrounding wall of the basin due to the rotation of the container. The thickened sludge is pumped out by pumping out the thickened sludge, and the discharge port drilled in the container is always or intermittently aligned with the opening in the side wall of the bowl, so that the pumped thickened sludge is discharged outside the bowl. A bowl-type centrifugal sedimentation separator featuring: (2) Two to four of the above-mentioned scooping containers are provided, each of which is provided at equal intervals surrounding the rotating shaft of the Recas screw conveyor, and is attached to the same number of driven shafts that are parallel to the shaft and connected with gears. A bowl-type centrifugal sedimentation separator according to claim 1, wherein the shaft is a hollow shaft that extends outside the bowl through a side wall of the bowl, and the hollow shaft forms a discharge port for the thickened sludge.