JP2936270B2 - Extrusion centrifuge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention has a centrifugal separator for separating solid and liquid using centrifugal force, in particular, a screen for solid and liquid separation, and has improved abrasion resistance thereof. It relates to an extrusion centrifuge.

[Conventional technology]

There are various types of centrifugal separators, such as a conical type and an Escher-Wis extrusion type.

The latter extruding centrifuge comprises a rotating outer cylindrical basket and an inner cylindrical basket disposed coaxially therewith, a cylindrical wire screen or plate screen fixed to the inner surface of each of the outer cylindrical basket, and the inner cylindrical basket. It has a continuous extrusion mechanism for extruding the basket forward and scraping and discharging the cake separated on the outer screen.

FIGS. 2 to 4 and FIGS. 5 to 5 illustrate screens for solid-liquid separation of a centrifuge having such a continuous extrusion mechanism.
There are so-called wire screens and plate screens respectively shown in FIG.

In manufacturing the wire screen, although not shown, first, a flat bar 232 arranged in a cylindrical shape with a stainless steel wire 231 having a wedge-shaped cross section spaced apart to form a gap 230 that allows only fluid to pass therethrough. And integrated by welding. Then, it is cut for each predetermined circumference and divided into several parts. Next, the wire 231 is reversely bent so that the outer peripheral surface of the wire 231 at the time of welding attachment becomes the inner peripheral surface. The form after the reverse bending is shown in FIGS. Here, the reason why the stainless steel wire 231 has a wedge-shaped cross section and performs reverse bending is as follows.
This is because the narrowest width of the gap (slit) 230 that allows only the fluid to pass through is extremely narrow, about 100 μm, in a state of being finally mounted on the inner surface of the basket of the separator, and it is difficult to obtain this by machining.

FIG. 2 shows a unit U which is cut at predetermined circumferential lengths, divided into several parts, and subjected to reverse bending after being integrated by welding. These segment-shaped units U, U... Are drawn in a cylindrical shape while their side edges are aligned with each other, and attached to the inner surface of the basket of the separator.

The plate screen is not shown, but first, a stainless steel plate 233 is cut to form a gap 230 ′ that allows only fluid to pass therethrough in the same manner as the wire screen.
To form Next, after performing reverse bending so that the outer peripheral surface at the time of cutting processing becomes the inner peripheral surface to obtain the shape shown in FIGS. This plate screen is used when it is not required that the width of the gap (slit) is as narrow as that of the wire screen.

[Problems to be solved by the invention]

However, in the conventional wire screen and plate screen, since simple stainless steel is used in a bare state, there is a problem that wear resistance is poor, replacement frequency is increased, and running cost and maintenance cost are increased.

SUMMARY OF THE INVENTION An object of the present invention is to provide an extrusion-type centrifugal separator that has been made to solve the above problems, is easy to process, has high wear resistance and corrosion resistance, and can reduce running costs and maintenance costs.

[Means for solving the problem]

The above object is to provide a rotating outer cylindrical basket and an inner cylindrical basket disposed coaxially with the rotating outer cylindrical basket, a cylindrical wire screen or a plate screen fixed to their respective inner surfaces, and pushing the inner cylindrical basket forward. In a centrifugal separator provided with a continuous extrusion mechanism for scraping and discharging the cake separated on the outer screen, a ceramic thin film having abrasion resistance and corrosion resistance is formed on a contact surface between the slurry of the screen and a solid material. Can be solved.

[Action]

In the present invention, a ceramic layer having abrasion resistance is formed on the contact surface of the screen for solid-liquid separation with the slurry, so that the screen can be used for a long period of time, and the running cost of the centrifuge is reduced. In addition, maintenance costs can be reduced. Further, in the present invention, in order to obtain a wear-resistant screen, it is sufficient to simply form a ceramic layer on the outermost surface, without using a difficult-to-process material as a material of the solid-liquid separation screen, using an easily processable material similar to the conventional one. The wear resistance can be improved without impairing the workability and hence the workability.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows the entire apparatus, in which a cylindrical casing 10 is fixed to the front of the apparatus, and an outer cylindrical basket 12 and an inner cylindrical basket 14 are coaxially arranged in the casing 10. An outer screen 16 and an inner screen 18 are fixed to the inner surfaces of these baskets 12, 14 by fixing means such as bolts.

On the other hand, the outer cylindrical basket 12 is integrated with a holding plate 12A bolted to the tip of the main shaft 20 by bolts,
The main shaft 20 is rotated by an output of a motor (not shown) being transmitted to a pulley 22, thereby rotating the outer cylindrical basket 12.
And the outer screen 16 rotates in the circumferential direction.

On the other hand, an extrusion shaft 24 is inserted with play into the main shaft 20, and its rear end is integrated with a piston 26. Further, a holding plate 14A is fixed to the tip of the extrusion shaft 24 by bolts, and the inner cylindrical basket 14 is integrated with the holding plate 14A by bolts.

Further, in the inner cylindrical basket 14, an extruding plate 28 and an integral distributor plate 30 are arranged parallel to and separated from the extruding plate 28. The pushing plate 28 is fixed to a holding plate 12A that holds the outer cylindrical basket 12 via a plurality of support arms 36 that penetrate the holding plate 14A with play. The distributor plate 3 is bolted to the extrusion plate 28.

Reference numeral 32 denotes a slurry supply pipe which communicates between the extruding plate 28 and the distributor plate 30 and supplies the slurry to be treated.
Numeral 34 denotes a cleaning liquid supply pipe which injects a cleaning liquid from a nozzle at the tip of the pipe to clean the cake deposited on the outer screen 16 and the inner screen 18.

In the centrifuge configured as described above, the slurry to be processed is supplied from the slurry supply pipe 32 between the extruding plate 28 and the distributor plate 30. At this time, the rotation of the main shaft 20 rotates the outer cylindrical basket 12 and the outer screen 16, and the support arm 36 penetrates the holding plate 14A, so that the inner cylindrical basket 14 and the inner screen 18 are also rotated in the same direction. .

During this rotation process, the pushing shaft 24 moves back and forth by the piston 26. Now, when the inner cylindrical basket 14 that has retreated moves forward, the pushing portion 14a at the front end thereof slides on the inner peripheral surface of the outer screen 16 and scrapes the cake deposited on the outer screen 16 forward. Discharge into the casing 10 from the end.

The inner cylindrical basket 14 from which the discharge has been completed retreats to the original position shown in the figure. The inner cylindrical basket 14 continuously receives the supply of the slurry, and the inner screen 18 on the inner surface thereof.
, A part of the slurry is transferred to the outer screen 16, and the solid-liquid separation is also performed on the outer screen 16. The filtrate at each screen 16, 28 is discharged into the casing 10 through the through holes in each basket 12, 14.

As is clear from the above description, each screen 16,
The particles 16 in the slurry collide with the particles 18 at high speed due to the centrifugal force, so that the screens 16 and 18 are extremely worn.

Therefore, in the present invention, a ceramic thin film having abrasion resistance and corrosion resistance is formed on the contact surface between the slurry of the screen and the solid material.

As shown in FIGS. 8 and 9 (in the case of a wire screen) and FIGS. 10 and 11 (in the case of a plate screen), as shown in FIGS.
A super hard ceramic coating layer 40 or 50 of a single layer or a composite layer of TiN, TiC, TiCN, Al ₂ O ₃ , C-BN or the like is formed. This carbide ceramic coating layer 40 or
50 can be formed by a known method such as a PVD method (physical vapor deposition method), a CVD method (chemical vapor deposition method), or ion plating, and the film thickness should be 0.1 μm to 10 μm. desirable. The point at which the super hard ceramic coating layer 40 or 50 is formed may be at the stage of the above-described material or at the stage after assembly.

Further, as shown in FIGS. 4 and 5, surface treatment layers 41 and 51 such as hard chromium plating and ion nitriding are formed on the first surface of the screen, and then the surface treatment layer 41 is formed on the composite layer. , 51 on the carbide ceramic coating layer
40, 50 can also be formed.

Further, the super hard ceramic coating layer 40 or 50 may be directly formed on a solid-liquid separation screen formed of a similar material in the related art.

Further, Ti may be used as a material of the solid-liquid separation screen itself, and a super hard ceramic coating layer may be formed directly after press working in the same manner as described above.

In the present invention, the outer / inner screen 16 for solid-liquid separation,
Since at least the outermost surface of the 18 is provided with the super hard ceramic coating layer 40 or 50, wear can be significantly reduced. By the way, although the life of the conventional screen was 2 to 3 months, the screen formed with the cemented carbide coating layer according to the present invention has
Its life could be extended to one year or more.

As a result, the frequency of replacement of the solid-liquid separation screens 16 and 18 was reduced, so that the running cost of the centrifuge could be reduced, and the maintenance cost required for replacement could be significantly reduced. These reduction effects greatly exceed the cost of forming a superhard ceramic coating layer on the screen for solid-liquid separation, and have a great economic effect.

〔The invention's effect〕

As described above, since the ceramic layer having abrasion resistance is formed on the contact surface of the screen for solid-liquid separation with the slurry, it is possible to improve the abrasion resistance without hindering the workability of the screen. As a result, the life of the screen has been extended more than three times compared with the conventional screen, and the maintenance cost has been reduced to 1/3.

In addition, the cost of forming a ceramic layer having abrasion resistance on the screen surface is lower than the cost in proportion to the life extension as compared with the conventional product, and the running cost can be reduced.

[Brief description of the drawings]

1 is an overall configuration diagram of an embodiment of the present invention, FIG. 2 is a perspective view of a wire screen, FIG. 3 is a view taken along line 3-3 of FIG. 2, and FIG. 4 is a view taken along line 4-4 of FIG. Fig. 5, Fig. 5 is a partial perspective view of the plate screen, Fig. 6 is a view taken on line 6-6 of Fig. 5,
7 is a view taken along line 7-7, FIG. 8 is a view corresponding to FIG. 3 of the wire screen of the present invention, and FIG. 9 is a view corresponding to FIG. 4 of the wire screen of the present invention. FIG. 10 shows the sixth embodiment of the plate screen according to the present invention.
FIG. 11 is an arrow view corresponding to FIG. 11, FIG. 11 is an arrow view corresponding to FIG. 7 of the plate screen in the present invention, FIG.
FIG. 13 is an arrow view showing another embodiment of the wire screen and the plate screen of the present invention. 10 ... casing, 12 ... outer cylindrical basket, 14 ... inner cylindrical basket, 16 ... outer screen, 18 ... inner screen, 20 ... main shaft, 24 ... extrusion shaft, 26 ... piston,
28 …… Extrusion board, 30 …… Distributor board, 32…
... Slurry supply pipe, 40, 50 ... Carbide ceramic coating layer, 41,51 ... Surface treatment layer.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B04B 7/00-7/18 B04B 3/00-3/08

Claims (1)

(57) [Claims] 1. A rotating outer cylindrical basket and an inner cylindrical basket disposed coaxially therewith, a cylindrical wire screen or a plate screen fixed to the inner surface of each of the outer cylindrical basket, and the inner cylindrical basket moving forward. In a centrifugal separator provided with a continuous extrusion mechanism for scraping and discharging the cake separated on the screen outside the extrusion, a ceramic thin film having abrasion resistance and corrosion resistance is formed on a contact surface between the screen slurry and a solid material. An extrusion-type centrifugal separator characterized in that: