JP2002153772A - Centrifuge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a horizontal centrifuge improved in the efficiency of separation and reduced in energy consumption and cost. SOLUTION: This centrifuge is composed of a bowl 1 rotating at a high speed and a screw conveyor 10 encased therein. The bowl 1 is a horizontal cylindrical straight drum having a port 7 for discharging a separated liquid C at the outer periphery of its rear wall 3 and has a mud discharging port 6 at its frontal inner periphery against which a press ring 8 is abutted. The rotary drum 11 of the conveyor 10 has a port for feeding a liquid (a) at its rear and has the ring 8 used for compacting a heavy component and a butted against its front. The bowl 1 has a mud discharge controller 20a being opposite to the ring 8 and used for compacting a heavy component at its frontal inner periphery against which it is abutted in a manner that it may move in the longer direction in response to the back pressure so as to automatically regulate the compaction of the heavy component and its delivery clearance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a straight-body centrifugal separator in which the concentration, dehydration, and recovery of solids and separated water of sewage sludge and industrial wastewater are performed by centrifugal force. .

[0002]

2. Description of the Related Art A decanter-type centrifugal separator has been generally used for solid-liquid separation of sludge and the like. As shown in FIG. 11, the separating device has a conical cylinder 41 at the end of a horizontally long straight body portion 40.
A screw conveyor 10 provided with a spiral blade 12 on an inner cylinder (inner rotating cylinder) 11 in a bowl (outer rotating cylinder) 1 which is formed at a high speed and rotated with a relative speed difference from the bowl 1 And a stock solution a such as sludge is supplied from the inner cylinder 11 into the front and rear central portions of the bowl 1 to perform solid-liquid separation by centrifugal force. The heavy component b sedimented and separated by the centrifugal force in the bowl 1 is sequentially raked toward the front end by the spiral blade 12, and further subjected to a consolidation and dewatering action in the conical cylinder 41, thereby causing The separated liquid C is discharged from the mud outlet 6 to the outside of the machine, and the separated liquid C is supplied to the rear end wall 3 of the bowl 1 on the opposite side.
Is overflowed and discharged from a discharge hole 42 provided at the bottom.

In this decanter-type centrifugal separator, the filtrate is stored in the bowl 1 so that the filtrate does not come out of the mud outlet 6 for discharging the cake, and is called a beach. The conical section lifts heavy components above the water level in the bowl and enhances the dewatering effect.
The feature is that a conical cylinder 41 whose front end is narrowed to a small diameter is required.

[0004] These conventional centrifugal separators have been developed for the concentration and dehydration of crystals and the like in a liquid phase, but are different from those for the concentration of substances to be treated such as sludge having different properties. When used for dewatering, the sediment layer of the sludge is paste-like and has a strong hydrophilicity, and in order to increase the dewatering rate, it is necessary to exert a strong consolidation effect so as to squeeze out water. In the above conventional decanter-type centrifugal separator, when the processing liquid a is supplied to the central part of the bowl 1, in the bowl straight body part 40 immediately after the supply, solid-liquid separation is performed by a high centrifugal force field (about 2000 to 3000G). Although it is done,
In the bowl conical portion 41 from which the heavy component b is discharged, since the distance (diameter) from the rotation center is short, the phenomenon that the centrifugal force is weakened and the water content is increased is seen. In fact, in the apparatus shown in FIG. 7, it has been observed that the moisture content is lowest at the d portion near the boundary between the straight body portion 40 and the conical portion 41. Furthermore, in order to discharge heavy components, it is necessary to raise the conical portion against strong centrifugal force, and even if it is attempted to transport by a screw conveyor, if the water content is low, co-rotation will occur due to frictional resistance. However, there is a tendency that only heavy components having a relatively high water content close to the rotation center of the straight body portion 40 are discharged, while the heavy components remain and are not discharged.

[0005] Further, since the heavy component b passes through a conical cylinder having a large inclination for discharging the water beyond the water level in the bowl, the heavy component b slips at this portion and the discharge becomes poor.
There is a disadvantage that the sludge is discharged from the separation liquid outlet 42 together with the separation liquid and the separation liquid becomes dirty. In addition, since the discharged heavy component having a relatively high water content close to the rotation center of the straight body portion 41 is discharged, the rotation of the bowl 1 is reduced in order to lower the water content of the discharged heavy component. It is the fact that the number is higher than necessary (about 2,000 to 3,000 rpm). Therefore, large power is required.

The present invention has been made to solve the above-mentioned problems in the decanter-type centrifugal separator. In the above-mentioned conventional centrifuge, the sludge is directly discharged from the d portion having the lowest water content. It is intended to obtain a centrifugal separator that can be drained. As a result, the separation efficiency can be improved by promoting the separation, the number of rotations of the bowl can be reduced, the power can be saved, and the apparatus can be simplified and downsized because it has no conical beach portion.

[0007]

In the separation apparatus of the present invention, the shape of the whole bowl is a straight cylinder of a horizontally long cylinder. Thereby, the residence time of the heavy component can be extended, and the solid-liquid separation can be sufficiently performed. Further, in the apparatus of the present invention, a suppression ring for consolidating heavy components and a sludge adjusting body opposed thereto are provided at a front end portion where heavy components are discharged, and the inner periphery of the bowl having the highest pressure density is provided. The heavy component can be taken out from the section through a narrow discharge gap, and the discharge gap is automatically adjusted according to the back pressure. As a result, the compaction action can be automatically adjusted by controlling the discharge pressure of the heavy component, and the solid-liquid separation performance can be improved and a stable heavy component can be obtained regardless of the properties of the stock solution.

[0008] In the apparatus of the present invention, a place for discharging the filtrate can be provided on the peripheral wall at the rear of the bowl.
A scraping blade for scraping off sludge adhering to the filtrate discharge section provided on the bowl peripheral wall may be provided.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show an embodiment of the apparatus of the present invention, FIGS. 4 to 6 show other embodiments of the heavy component discharge section, and FIGS. 7 to 10 show other embodiments of the separated liquid discharge section. It shows an embodiment.

1 to 3, reference numeral 1 denotes a bowl (outer rotating cylinder) which is rotated at a high speed, and has a horizontal cylindrical straight body shape. 5 is protruded, is supported by a bearing (not shown), and is rotated at a high speed by a driving device. A plurality of mud holes 6 are provided on the peripheral wall at the front end of the bowl 1 along the circumferential direction. In the rear end wall 3 of the bowl 1, an outlet 7 for the separated liquid is provided. This discharge hole 7 is, for example,
Although illustration is omitted, it is preferable that a plurality of fan-shaped ones be spaced in the circumferential direction, or that a large number of small holes be spaced along the outer peripheral portion of the rear end wall 3.

Reference numeral 10 denotes a screw conveyor housed in the bowl 1 and a spiral wing 12 is wound around the outer periphery of a horizontal cylindrical rotating drum 11 and both ends thereof are connected to the hollow shafts 4 and 5 of the bowl 1.
The rotating shaft 13 is supported by a protruding portion inside the bowl and is rotated with a required speed difference from the bowl 1 by a rotating shaft 13 inserted through the hollow shaft 4. A supply chamber 14 for a stock solution a is provided on the rotating drum 11, and the bowl 1 and the rotating drum
A supply port 15 communicating with an annular space 17 is provided between the supply chamber 15 and the supply pipe 15 for the undiluted solution inserted through the rear hollow shaft 5 of the bowl 1. The front end of the rotary drum 11 has a tapered surface 8a on the outer periphery at a position corresponding to the rear part of the mud hole 6 so that the side facing the rear end has a tapered surface 8a for consolidating the heavy component b to be discharged. The pressing flange 8 is provided around.

Immediately after the discharge port 6 of the bowl 1 is provided, at a position facing the pressing flange 8, the opening degree of the discharge port 18, which is a discharge gap with the suppression flange 8, is determined by the heavy component. A sludge adjustment ring 20 that automatically adjusts according to the discharge pressure of the oil is provided to protrude. This sludge adjusting ring 20 contacts the inner periphery of the bowl 1,
A main body ring 21 having a mountain-shaped cross section having a tapered surface 21a on the side facing the rear end.
On the outer periphery of the arm, a leg piece 22 protruding into each of the mud holes 6 protrudes, and the leg piece 22 is provided with an insertion rod 23 protruding in the rear end direction. Then, insert the insertion rod 23 into the bowl 1
Of the bowl 1 and is normally urged by the spring 25 toward the rear end of the bowl 1 so as to resist the spring 25 in response to the heavy component discharge pressure. It moves toward the front end of the bowl 1 so that the width of the gap (discharge port) 18 is automatically adjusted. Note that hydraulic or pneumatic means can be used in place of the spring 25.

In the above apparatus, the undiluted solution a enters the supply chamber 14 from the supply pipe 16 as shown by the arrow, is supplied into the annular space 17 from the supply port 15, and is supplied to the bowl 1 and the screw conveyor 10.
The liquid is conveyed toward the front end by the spiral blade 12 while being separated into solid and liquid by the centrifugal force of the rotation. Then, the separated liquid C, which is the separated liquid, is discharged outside the apparatus through the discharge hole 7 in the rear end wall.

The heavy component b including the solid and liquid components is supplied to the spiral blade 12
While being squeezed toward the front end of the bowl 1 by the centrifugal force, separation of the remaining liquid proceeds, and the separated liquid C is also discharged from the discharge hole 7. The heavy component b transported to the front of the bowl 1
The condensate action is exerted by the sludge adjusting ring 20 protruding from the front end and the pressing flange 8 at the front end of the rotating drum 11. At this time, the adjusting ring 20 is pushed toward the front end of the bowl 1 as shown by an arrow in FIG. 2 against the spring 25 in accordance with the pressure acting on the tapered surface 21a.
It is discharged from the discharge port 18 formed between the pressing flange 8 and the discharge port 6.
Spilled out of the aircraft. Then, the discharge port 18 flows out of the apparatus according to the back pressure. The size of the discharge port 18 is automatically adjusted according to the back pressure.

FIGS. 4 to 6 show another embodiment in which the pressing flange 8 and the adjusting ring 20 are provided. In the embodiment of FIG. 4, the cross-sectional shape of the pressing flange 8 is changed. The side facing the rear end is a substantially orthogonal surface 8b, and the side facing the front end is substantially parallel to the tapered surface 21a of the sludge adjusting ring 20. It is a tapered surface 8c. In the embodiment of FIG. 5, the pressing ring 8 does not have a mountain-shaped cross section, but has a vertically long surface 8b whose surface facing the rear end is substantially orthogonal. Figures 1 to 3 show the effect
It is almost the same as that of the embodiment.

In the embodiment shown in FIG. 6, the pressing flange 8 has a mountain-shaped cross section, contrary to the embodiment shown in FIG.
The sludge adjusting ring 20 has an upright surface 21b on the side facing the rear end without making the cross-sectional shape of the main body ring 21 mountain-shaped, and the top of the pressing flange 8 is located outward from the inner end of the main body ring 21. It is located.

In the apparatus of the present invention, a place for discharging the filtrate may be provided on the peripheral wall of the bowl 1. 7 and 8 show the embodiment. In this embodiment, a discharge port is not provided in the rear end wall 3, and a discharge part 30 for filtrate is provided in the peripheral wall at the rear part of the bowl 1 instead.
As shown in FIG. 8, for example, the filtrate discharge portion 30 includes a plurality of discharge holes 31 formed in the circumferential direction and a porous plastic molded body for filtering solids, a wire net, ceramic, metal, and the like inside the discharge holes 31. It has a structure in which a screen 32 made of a sintered body, a filter cloth, or the like is provided. The structure of the filtrate discharge section 30 is not limited to the above-described structure, and the structure can be appropriately changed as long as the structure includes a combination of the discharge hole 31 and the screen 32.

As described above, in the case where the discharge point of the filtrate is provided on the peripheral wall of the bowl 1, the separated liquid C is discharged immediately after the supply of the undiluted solution, so that almost a water surface is generated in the bowl 1. Therefore, the solid-liquid separation is performed more efficiently.

Further, in the apparatus of the present invention, as shown in FIG. 9, the discharge point of the filtrate is changed to the bowl rear end wall 3 as in the embodiment of FIG. 1 and the bowl 1 as in the embodiment of FIG. May be provided on the peripheral wall. That is, the discharge port 7 is provided on the rear end wall, and the filtrate discharge section 30 is provided on the peripheral wall of the bowl. In this way, the separated liquid C is discharged from both the discharge port 7 and the filtrate discharge part 30, so that the sludge having a low concentration or the high-load sludge can be efficiently processed.

FIG. 10 shows an embodiment in which a means for scraping off the sludge adhering to the filtrate discharge section 30 is provided. That is, in this embodiment, toward the screw conveyor 10,
Corresponding to the filtrate discharge section 30, a part of the spiral blade 12 is cut out, and the tip of the rotary cylinder 11 is in sliding contact with the screen 32, and the scraping blade 33 of the sludge adhered to the screen 32 is cut off. Multiple are mounted radially. It is preferable that the scraper blades 33 not only scrape the sludge adhering to the screen 32 but also maintain an angle with respect to the axis so as to have a conveying force for the sludge. In the embodiment of FIG. 17, the outlet 7 is provided in the rear end wall 3 of the bowl 1, but the outlet 7 may not be provided.

The sludge adhering to the screen 32 of the filtrate discharge unit 30 can be scraped to some extent by the spiral blade 12 of the screw conveyor 10. But spiral wings 12 and screen
Since there is a slight gap between the inner surface of the screw 32 and the rotation speed difference between the bowl 1 and the screw conveyor 10, the scraping by the spiral blade 12 is slow. Insufficient scraping results in clogging of the screen 32 and poor discharge of separated water. Therefore,
In the apparatus of this embodiment, the scraper blades slidingly contacting the screen 32
33 is provided so that sludge can be scraped positively.

[0022]

As described above, according to the centrifugal separator of the present invention, the discharge part of the filtrate (separated liquid) is provided on the peripheral wall at the rear part of the bowl or the peripheral part of the rear end wall, and the undiluted liquid is filtered. Since the liquid is supplied into the bowl with the liquid discharge section (discharge hole), the suppression ring and the sludge adjusting body are provided opposite the front end of the bowl and the front end of the rotary cylinder of the screw conveyor.
It has many excellent effects as follows.

(1) A long cone with a long inclination and a large throttle as in the conventional machine by providing a bowl with a straight body shape and providing a suppression ring and a sludge adjusting body at the heavy component discharge portion. It is not necessary to provide a cylinder, and it is possible to smoothly transport and discharge heavy components having a low water content.

(2) The heavy component is condensed by the suppression ring and the sludge adjusting member at the outlet thereof, so that the solid-liquid separation performance is further improved. However, since it moves according to the magnitude of the back pressure and automatically adjusts the opening of the discharge port, it is possible to adjust the compaction action by suppressing the discharge of heavy components freely and automatically without manual operation, The solid-liquid separation performance can be improved, and a stable heavy component can be obtained.

(3) In a device provided with a filtrate discharge portion on the peripheral wall, since filtration is performed by a screen, the properties of the separated water are good and the occurrence of a water surface in the bowl can be prevented. In particular, in a device provided with a sludge scraper blade, clogging of the screen can be prevented, and operation efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of the apparatus of the present invention.

FIG. 2 is a sectional view taken along the line II in FIG.

FIG. 3 is a cross-sectional view taken along a line of FIG.

FIG. 4 is a side sectional view showing another embodiment in which a pressing flange and a discharge adjusting ring are provided.

FIG. 5 is a side sectional view showing still another embodiment.

FIG. 6 is a side sectional view showing still another embodiment.

FIG. 7 is a side sectional view showing another embodiment of the filtrate discharge part.

FIG. 8 is an enlarged side sectional view of a filtrate discharge part.

FIG. 9 is a side sectional view showing still another embodiment of the filtrate discharge part.

FIG. 10 shows still another embodiment.

FIG. 11 is a side sectional view showing a conventional decanter-type device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bowl 2 Front end wall 3 Rear end wall 6 Discharge port 7 Filtrate discharge port 8 Suppression flange 10 Screw conveyor 11 Rotary drum 12 Spiral wing 14 Supply chamber 15 Supply port 16 Supply pipe 17 Annular space 18 Discharge port (discharge gap) 20 Sludge adjustment ring 21 Body ring 22 Leg piece 23 Insertion rod 24 Engagement hole 25 Spring 30 Filtrate discharge part 31 Drain hole 32 Screen 33 Scraper blade

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuyuki Yoshida 1-2-47 Shikitsuhigashi, Naniwa-ku, Osaka-shi Kubota Osaka Head Office (72) Inventor Hiroyuki Matsui 1-2- Shikitsuhigashi, Naniwa-ku, Osaka-shi 47 Kubota Osaka Co., Ltd. (72) Inventor Takashi Uchikawa 2-1-6 Nishijima, Nishiyodogawa-ku, Osaka City F-term in Kubota Shinyodogawa Environmental Plant Center (reference) 4D057 AA11 AB01 AC01 AC06 AD01 AE03 AF01 BA11 BA13 BA17 BA20 BA43 BC05 BC11 BC12 BC15 BC16 CB01

Claims (4)

[Claims] 1. A screw conveyor rotated at a relative speed difference is accommodated in a bowl rotated at a high speed, and heavy components are separated and settled by centrifugal force from a stock solution supplied into the rotating bowl. Is transferred to the front end of the bowl by a screw conveyor and discharged, the bowl is formed into a straight cylindrical shape of a horizontal cylinder, a discharge hole for the separated liquid is provided in the rear end wall of the bowl, and the screw conveyor On the outer periphery of the front part of the rotating drum, a suppression flange that gives a consolidation effect to the heavy component protrudes, and on the inner periphery behind the mud outlet at the front of the bowl, the suppression flange is opposed to the suppression flange. A centrifugal separator characterized in that it has a condensate action and a sludge adjusting ring that automatically adjusts the discharge gap between itself and the suppression collar in accordance with the back pressure. 2. A liquid discharge part comprising a discharge hole for a separated liquid and a filtration screen attached thereto is provided on the peripheral wall at the rear part of the bowl instead of the discharge port on the rear end wall of the bowl. The centrifugal separator according to claim 1. 3. A filtrate discharge portion comprising a discharge hole for a separated liquid and a filtration screen attached thereto is provided on a peripheral wall at a rear portion of the bowl in addition to a discharge port on a rear end wall of the bowl. The centrifugal separator according to claim 1. 4. The screw conveyor according to claim 1, wherein a spiral wing of the screw conveyor is cut out, and a sludge scraping wing attached to a screen of a filtrate discharge part provided on a peripheral wall of the bowl is provided in that portion. Centrifuge.