JPH0459065A - Screw centrifugal separator - Google Patents

Abstract

PURPOSE:To efficiently separate and discharge even a pasty and soft solid component at a low cost by providing a screw conveyor shaft and plural scrapers in sliding contact with the guide surface of a rotary drum and supplying an original liq. to the separation part through the hollow part of the conveyor shaft. CONSTITUTION:An original liq. supplied to a rotary drum 1 through a feed pipe 17 is firstly centrifugally separated in the separation part 1a, and the separated low-specific-gravity component L is discharged from an outlet 18. The concd. high-specific-gravity component H is gradually moved toward the scraping part 1b by the spiral blade 9 of a screw conveyor shaft 7 and concentrated, introduced into the scraping part 1b from the clearance between a partition plate 12 and the drum 1, the solid component in the liq. concentrate is scraped by a scraper 10 and discharged from an outlet 19 through the beach zone Z and liq. concentrate discharge hole 6. Consequently, the cost is reduced, the turning rate is further increased, and a centrifugal effect is enhanced.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a screw type centrifuge.

[Conventional technology]

The Tecantor type is widely known as a screw type centrifuge, and as shown in the sectional view in Figure 4, this centrifuge has a screw container inside a so-called rotary body that has a tapered truncated cone at one end. By coaxially supporting the rotary drum and the screw container, and rotating them at high speed in the same direction with a slight speed difference, the stock solution in the rotary drum is separated into light liquid components and heavy liquid components using centrifugal force. To separate.

In this decanter type centrifuge, the separated light liquid component moves to the inner layer within the rotating barrel based on the difference in specific gravity, and is taken out from the large diameter end of the rotating barrel, and the separated heavy liquid moves to the outer layer. The components are taken out from the small diameter end of the rotating barrel.

However, this type of separator can be used to process pasty and flexible solids such as solid-liquid separation of reaction liquids from bioreactors, concentration of sewage sludge, separation of suspensions in fruit juices, and separation of colloidal particles in the fine chemical field. When used for this purpose, there are the following problems.

In other words, in the beach zone of the inclined part of a decanter-type centrifuge, as shown in the partial vertical cross-sectional view of FIG. and move toward the small diameter end,
If the slope of the inclined portion is increased in order to shorten the rotating body, the sliding force will also increase in proportion to the slope. If the slope of the slope is made smaller in order to reduce the sliding force, the length of the rotary drum increases, resulting in an increase in cost.

In addition, if the solid content in the heavy liquid component is difficult to shear and deform, the lifting force of the screw conveyor will work effectively and the solid content can be lifted efficiently, but if the solid content is Pasty and flexible materials such as chemical products may leak through the gap between the rotary drum and the screw conveyor or slide down along the helical blades, preventing the lifting force from working effectively and reducing efficiency. I can't stir fry well.

As a means to solve this problem,
The means proposed in JP-A No. 58-43253 and the means proposed in JP-A No. 58-43253 are known.

In the former case, an annular baffle plate is installed near the boundary between the inclined part of the rotating barrel and a part of the decanter, and by adjusting the interface height between the light liquid and heavy liquid in the straight barrel part, the liquid level of the heavy liquid in the inclined part can be adjusted. Drain the heavy liquid by aligning it with the heavy liquid discharge port. However, with this method, the flow of heavy liquid tends to become unstable and pulsating because sludge accumulates in front of the discharge port and obstructs the flow of heavy liquid, and if the properties of the raw liquid or the throughput change,
It is difficult to handle because the light liquid outlet weir plate needs to be replaced.

In the latter case, a relatively large slope part and a relatively small slope part are formed in tandem in the slope part, but if the solids are difficult to discharge, the small slope part becomes quite long, so the equipment cost is reduced. , the installation area increases.

[Problem to be solved by the invention]

The present invention was proposed in view of these circumstances, and is a high-performance and economical method that shortens the axial length, makes it easy to handle, and is low-cost and capable of efficiently separating and discharging even pasty and flexible solid components. The purpose of this invention is to provide a screw-type centrifugal separator.

[Means to solve the problem]

To this end, the first invention consists of a relatively long separation part extending from one end of the cylinder to near the other end, and a relatively short rake part in the remaining part, both ends of which are closed by end plates each having a center hole, and which extend around the central axis. The rotary cylinder rotates at high speed, and the rotary cylinder is wound spirally around the outer periphery of a hollow shaft portion that coaxially passes through the rotary cylinder and forms a portion spanning the separation portion, and the outer edge of the rotary cylinder has a slight gap. A screw conveyor shaft that has helical blades facing the inner surface of the shaft and rotates at high speed with a slight difference in speed; It is equipped with a plurality of scrapers that come into sliding contact with the guide surface of the rotating barrel, and supplies the raw liquid to the separating section of the rotating barrel through the hollow shaft of the screw conveyor shaft, and passes the light liquid across the end plate at one end of the separating section. It is characterized in that, at the same time as the heavy liquid is taken out, the heavy liquid is taken up from the lifting part through its discharge hole.

Further, a second invention is the first invention, in which the inner peripheral part is attached to the screw conveyor shaft at the boundary between the separating part and the scraping part, and the heavy liquid flows from the separating part to the scraping part along the inner surface of the rotary drum. The present invention is characterized by comprising an original plate-like partition plate having a narrow gap in the radial direction that allows movement of the partition plate.

[For production]

According to the first invention, light liquid is separated in the same way as a decanter type centrifuge by the action of centrifugal force in a rotating drum that rotates at high speed, and heavy liquid is concentrated as the light liquid is separated and transferred to a screw conveyor. By moving toward the scraping part by the shaft, it moves in the rotary drum from the separation part to the scraping part while concentration progresses.

In the scraping section, a scraper attached to a screw conveyor shaft that rotates at a relatively low speed relative to the rotary drum slides against the non-concentric circular guide surface of the scraping section, thereby scraping heavy liquids, especially the solids contained therein. is raked over the beach and discharged to the outside through radial discharge holes in the raking section.

If a partition plate is installed at the boundary between the separation section and the raking section,
The partition plate preferentially introduces the concentrate into the raking section, and
By effectively scraping the concentrate in cooperation with the scraper, even flexible solids can be efficiently separated.

〔Example〕

One embodiment of the present invention will be explained with reference to the drawings. Fig. 1 is a longitudinal cross-sectional view of the whole, Fig. 2 is a cross-sectional view of Fig. 1, and Fig. 3 is a cross-sectional view of Fig. 1.
The figure is the same <n-:n sectional view showing a modification of FIG. 2.

The present invention differs greatly from the structure shown in FIG. 4 by eliminating the inclined part of the rotating body and making the entire rotating body cylindrical, and also by eliminating the conical spiral blade part of the screw conveyor and making the entire rotating body a cylindrical spiral blade part. The most important feature is that the heavy liquid discharge side of the rotary drum is used as a scraping section, and the inner circumferential surface of the rotary drum is scraped with scrapers that protrude radially from the shaft end of the screw conveyor. .

First, in Figs. 1 and 2, reference numeral 1 denotes a horizontal cylindrical rotating body, whose front and rear ends are respectively closed by a front end plate 2 and a rear end plate 3 from which a hollow journal projects. Separation part 1a extending from front end plate 2 to near rear end plate 3
and the remaining part, the scraping part 1b having a slightly larger diameter.

A guide member 5 forming a guide surface 4 having a so-called cocoon-shaped cross section with a constriction in the center is fitted onto the inner surface of the rotating body in a portion forming the raking part ib, and a guide member 5 is fitted into the constricted part to penetrate through the rotating body. A diametrical concentrate discharge hole 6 is provided therethrough. Reference numeral 7 denotes a screw conveyor shaft, which is coaxially supported on the rotating body 1 via its front and rear end journals and bearings on the front end plate 2 and rear end plate 3, and is attached to the outer periphery of the hollow shaft portion 8 spanning the separation portion 1a. A helical blade 9 is protruded in a winding manner, and its leading edge ≠- faces the inner surface of the rotary cylinder of the separation part 1a with a small gap, and the part extending over the scraping part 1b is slidable in the outward radial direction. A pair of rectangular scrapers 10 supported by a pair of rectangular scrapers 10 are disposed substantially diametrically symmetrically, and their outer edges are in sliding contact with the cocoon-shaped guide surface 4 of the guide member 5.

Reference numeral 12 denotes an annular plate-shaped partition plate which is fixed to the screw conveyor shaft 7 at the boundary between the separating section 1a and the scraping section 1b and faces the inner surface of the rotary cylinder with a narrow gap in its outer periphery;
16 is a front end plate 2 of the rotating body 1;
Each hollow journal of the rear end plate 3 is connected to the casing 15.
17 is a stock solution supply pipe inserted into the hollow shaft part 8 of the screw conveyor shaft 7, and 18 and 19 project downward from the front and rear ends of the casing 15, respectively. Separated liquid outlet and concentrated liquid outlet provided; 20.
21 are a motor and a speed reducer, respectively.

In such a structure, the stock solution supplied to the rotary drum 1 via the stock solution supply pipe 17 is first centrifuged in a known manner in the separating section 1a, and the light specific gravity components are discharged as a separated liquid through the separated liquid outlet 18. is discharged from.

The heavy specific gravity component H concentrated along with the separation of the light liquid component is sent to the scraping section 1 by the helical blade 9 of the screw conveyor shaft 7.
It is concentrated while gradually moving toward b, and the partition plate 12
It enters the raking section 1b through the gap between the rotary drum 1 and the rotary drum 1, where
As shown in FIG. 2, the solid content in the concentrated liquid is scraped by a scraper 10 that slides along the cocoon-shaped guide surface 4, passes over the beach zone Z, passes through the concentrated liquid discharge hole 6, and exits from the concentrated liquid discharge port 19 of the casing. It is discharged.

The partition plate 12 partitions the heavy liquid component and the light liquid component, and also preferentially introduces the concentrated meA into the scraping section.At this time, it faces the scraper 10 to increase the scraping efficiency, and the screw conveyor Instead of being fixed to the shaft, it can also be fixed to the rotating body.

Note that, depending on the purpose of use, the partition plate may be omitted to simplify the side passage, although the performance will be slightly degraded.

Moreover, as shown in FIG. 3, the guide member 5a having an eccentric circular guide surface 4a can be adopted as the guide member 5, and in this case, Za becomes the beach zone.

In this embodiment, the raking part is connected to the separating part of the straight body, but a structure in which the raking part is connected to the separating part having an inclined part is also possible.

〔effect〕

According to the screw type centrifugal separator having the configuration and operation described above, the following effects can be achieved, so that the present invention is extremely useful industrially.

(1) Since the rotary cylinder is a cylindrical cylinder without an inclined part, its overall length can be shortened and manufacturing becomes easier, which reduces costs and further increases the rotational speed to enhance the centrifugal effect. I can do it.

(2) Since the discharge of concentrated liquid is continuously stabilized, even highly concentrated liquid can be treated.

f3) 'a The discharge of the condensed liquid can be easily controlled by the differential speed regulator between the rotary drum and the screw conveyor shaft.

(4) Even if the solid material is paste-like and flexible,
Concentrate can be discharged stably.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention, Fig. 2 is a cross-sectional view taken along ■-■ of Fig. 1, and Fig. 3 is a cross-sectional view of the same <I-II showing a modification of Fig. 2. It is. Figure 4 shows a known decanter.
FIG. 5 is an enlarged view of the beach zone portion of FIG. 4. 1; Rotating cylinder, la; Separation part, Ib; tM lift part, 2; Front end plate, 3; Rear end plate, 4.4a; Guide surface, 5.5a;
Guide member, 6; Concentrate discharge hole, 7; Screw container shaft, 8. Hollow shaft portion, 9; Spiral flade, lO; Scraper, 12; Partition plate, 15; Casing, 16;
Main bearing, 17; Raw solution supply pipe, 18; Separated liquid outlet, 19
Concentrated liquid outlet, 20; Motor, 21; Reducer, F liquid level, G: Stock liquid, H: Concentrated liquid, L: Separated liquid, Z, Za bead zone.

Claims (2)

[Claims] (1) A rotating body consisting of a relatively long separation part extending from one end of the cylinder near the other end, and a relatively short lifting part in the remaining part, both ends of which are closed by end plates each having a center hole, and which rotates around the central axis. and is spirally wound around the outer periphery of a hollow shaft that coaxially penetrates the rotary shell and forms a portion spanning the separation section, and the outer edge faces the inner surface of the rotary shell with a slight gap. A screw conveyor shaft having helical blades and rotating with a slight difference in speed; and a screw conveyor shaft that extends radially across the scraping portion of the screw conveyor shaft and is biased outwardly and radially by centrifugal force, and its leading edge guides the rotary cylinder. a plurality of scrapers that come into sliding contact with the surface, supply the raw liquid to the separation section of the rotary barrel through the hollow shaft of the screw conveyor shaft, cross the end plate on one end side of the separation section to take out the light liquid; A screw type centrifuge, characterized in that the heavy liquid is taken out from the scraping section through its discharge hole. (2) In the screw type centrifuge according to claim 1, the inner peripheral portion is attached to the screw conveyor shaft at the boundary between the separating section and the scraping section, and the inner circumference is attached to the screw conveyor shaft along the inner surface of the rotating barrel from the separating section to the scraping section. 1. A screw type centrifugal separator characterized by comprising an annular plate-shaped partition plate having a narrow gap in the radial direction to allow movement of heavy liquid flowing into the centrifuge.