JP2019076933A - Screen of screw press - Google Patents

Abstract

To provide a screen of a screw press capable of reducing a dehydrated cake water content by improving fillability of a filtration chamber to a stock solution having low flowability.SOLUTION: A screw press includes a supply pipe connected to a starting end wall of a filtration chamber, such a screw blade that a starting end part of the screw blade is provided with a prescribed gap between itself and the starting end wall, and a screen having a nonporous cylinder part not having fine pores as long as a prescribed width on the starting end side. Hereby, accumulation of a solid portion on the filtration chamber starting end side is prevented, and a stock solution can be filled easily into a spiral passage of the screw blade, to thereby improve dewaterability.SELECTED DRAWING: Figure 2

Description

  The present invention relates to improvement of the dewatering performance of a screw press, and more particularly to a screen of a screw press which reduces the moisture content of the dewatered cake by improving the filling capacity of the filtration chamber.

Conventionally, screw presses for concentrating and dewatering organic sludge such as sewage, human waste, or food production processing drainage are generally known. The screw press is a device in which screw blades are inserted into a cylindrical screen, and the screw blades are rotated to convey the sludge while performing solid-liquid separation on the screen.

Further, in a screw press, there is also known a screen in which both ends are formed as non-porous cylinders in relation to the configuration and the mounting and demounting flange.

For example, the screen of the screw type concentrator disclosed in Patent Document 1 is configured such that both ends of the cylindrical screen have a predetermined width in a non-porous cylinder from the viewpoint of the configuration and strength of the supply and discharge of the stock solution.

  The screen of the screw type concentrator disclosed in Patent Document 2 describes that the aggregation portion is formed in the non-porous cylinder after supplying the stock solution by making the supply unit a non-porous cylinder.

Furthermore, in the screw press, the supply pipe of the undiluted solution is connected to the beginning end wall of the filtration chamber, and the undiluted solution is supplied to the filtration chamber in the axial direction of the screw shaft. A screw press having a predetermined gap between is also known, and is disclosed, for example, in Patent Document 3.

Patent No. 3627809 gazette Japanese Utility Model Publication No. 56-24634 Patent No. 4014531

In general, since the hole diameter for solid-liquid separation provided in the screen of a screw press is small, the screen is formed of a thin plate in terms of processing. In order to prevent the screen from being damaged by the internal pressure of the filtration chamber etc., it has reinforcing means such as reinforcement with a punching metal with a large diameter opening at the outer peripheral part of the screen or arranging ribs at predetermined intervals. ing.

In addition, the beginning of the screw blade inserted into the screen and the beginning wall of the filtration chamber have a gap, and solid content of the undiluted solution which is not conveyed by the screw blade may accumulate there.

Patent Document 1 is configured to supply the undiluted solution from the circumferential surface of the screen and discharge the dewatered cake from the circumferential surface of the screen. From the viewpoint of strength, it is recognized that both ends of the screen are non-perforated.

Although patent document 2 provides a non-porous cylinder part with a large width in the axial direction of a screen, and forming a flocculated floc in a non-porous cylinder is described, the undiluted solution is supplied from a screw axis. Therefore, the stock solution is easily deposited on the front end side of the filtration chamber, and there is no description or suggestion about the gap between the front end of the screw blade and the front end wall of the filtration chamber. Moreover, since the non-perforated cylindrical part is provided by the big width | variety, in order to ensure a filtration area, the subject that the full length of a screw press becomes long occurs.

Patent document 3 connects the supply pipe of the undiluted solution to the start end wall of the filtration chamber, and supplies the undiluted solution to the filtration chamber in the axial direction of the screw shaft. A predetermined gap is provided between the filtration chamber and the beginning end wall of the filtration chamber. However, the fine pores of the screen are provided up to the start wall, and particularly in the case of a low-flowing undiluted solution, solid content is deposited in this gap and sufficient solid-liquid separation can not be performed. Also, it is unclear whether the position of the supply pipe is connected to the upper side or the lower side of the filtration chamber.

The present invention provides a screen of a screw press which improves the strength of the screen of the screw press and prevents solids from being deposited on the front end side of the filtration chamber.

  According to the present invention, a screw shaft having a screw blade wound around the inside of the screen is rotatably installed to form a filtration chamber, and the stock solution supplied from one end of the filtration chamber is conveyed to the other end while being dewatered. A screw pipe for discharging a dewatered cake, a feed pipe connected to the beginning end wall of the filtration chamber, a screw vane having a predetermined gap between the beginning end of the screw vane and the beginning end wall of the filtration chamber; And a screen having a non-porous cylindrical portion not having micropores of a predetermined width, so that solid content is prevented from being deposited on the start side of the filtration chamber, and the undiluted solution is It is easy to be filled and the dewaterability is improved.

  If the width of the non-porous cylindrical portion of the screen is 1 to 1.5 times the gap (Ls) between the front end of the screw blade 6 and the front end wall of the filtration chamber, even undiluted liquid with low fluidity moves the non-porous cylindrical portion Can reach the beginning of the screw blade and can be transported and dewatered.

  The screen includes a cylindrical body having a large number of fine holes, a flange connected to the front and back of the cylindrical body, and an outer cylinder provided around the outer periphery of the cylindrical body, the outer cylinder having an opening larger than the fine holes. In the case of forming the hole cylinder portion and the non-hole cylinder portion having no opening with a predetermined width, the strength member can be provided around the cylinder body, so that breakage of the cylinder body can be prevented.

According to the present invention, since the non-porous cylindrical portion is provided with a predetermined width from the beginning end side of the filtration chamber, the stock solution reaches the screw blade in a fluid state and the stock solution adheres at the beginning end of the filtration chamber I have not.

The non-perforated cylindrical portion increases the strength of the cylindrical screen, and the length of the non-perforated cylindrical portion only needs to be formed to the beginning of the screw blade, so the overall length of the screw press does not increase.

Even if the high concentration undiluted solution with poor fluidity is incorporated into the screw blade at an early stage containing a large amount of water, the screw rotates in a state that the undiluted solution is filled in the flow path of the screw blade inside the filtration chamber. Improve the rate.

It is a vertical side view of a screw press concerning the present invention. Similarly, it is the enlarged view of the supply side of a screw press. Similarly, it is a longitudinal side view of a screen. Similarly, it is a longitudinal side view of the screen of other Example 1. FIG. Similarly, it is a longitudinal side view of the screen of other Example 2. FIG.

FIG. 1 is a longitudinal side view of a screw press. Reference numeral 1 denotes a screw press, which is supported by front and rear frames 3 and 4 erected on a gantry 2. In the screw press 1, a screw shaft 7 in which a screw blade 6 is wound around a screen 5 having a filtration surface at the periphery is provided internally, and a filtration chamber 13 is formed therebetween. The screw shaft 7 disposed inside the screen 5 has its diameter increased in a tapered manner from the start end side to the end side, and the relative distance between the screen 5 and the screw shaft 7 is reduced in the drawing direction. ing.

The front end of the screw shaft 7 is supported by a bearing 8 provided on the frame 3, and the rear end is supported by a bearing 18 mounted on a member erected from the gantry 2. A screw drive shaft 10 is connected to a rear end portion of the screw shaft 7, and a driving sprocket 11 is fitted to the screw drive shaft 10. The sprocket 11 is driven by a screw drive (not shown) to rotate the screw shaft 7.

The start end wall of the filtration chamber 13 is constituted by the frame 3 on the front side, and a supply pipe 9 communicating with the filtration chamber 13 is connected to the start end wall, and the stock solution is supplied to the start end of the filtration chamber 13. The stock solution supplied from the supply pipe 9 is transferred by the screw blade 6 from the start end side to the end side, and is concentrated / dehydrated while separating the filtrate from the screen 5. The dehydrated cake dehydrated in the filtration chamber 13 is discharged from the discharge unit 12. The screen 5 may be rotatable as required.

FIG. 2 is an enlarged view of the supply side of the screw press. A supply pipe 9 is connected near the bottom of the start end wall of the filtration chamber 13 to supply the stock solution to the filtration chamber 13 in the axial direction of the screw shaft 7. When the starting end of the rotating screw blade 6 is positioned downward, the starting edge of the screw blade 6 and the starting end wall of the filtration chamber 13 are obstructed by the screw blade 6 to inhibit the supply of the stock solution in the axial direction. And a predetermined gap Ls is provided. A space of only the screw shaft 7 exists at the beginning of the filtration chamber 13 by the gap Ls.

A cylindrical screen 5 is provided around the outer periphery of the screw blade 6, and solid solution separation of the stock solution supplied from the supply pipe 9 to the filtration chamber 13 is performed. The screen 5 has a non-porous cylindrical portion 5 c having no fine hole from the start end of the filtration chamber 13 to the vicinity of the start end of the screw blade 6 by a predetermined width Ws.

FIG. 3 is a longitudinal side view of the screen, and the screen 5 is composed of a cylindrical body 14 having a large number of fine holes and flanges 15 and 16 connected to both ends of the cylindrical body 14. The flanges 15 and 16 are attached to the front and rear frames 3 and 4 respectively.

The cylindrical body 14 is composed of a non-porous cylindrical portion 5c not having a minute hole of a predetermined width Ws on the start end side (right side in the drawing) and a hole cylindrical portion 5f having a minute hole. In the non-porous cylindrical portion 5c, there is no fine hole that communicates the filtration chamber 13 with the outside, so that the water is not separated from the undiluted solution in the filtration chamber 13 to the outside. The water in the stock solution passes through the fine holes in the hole cylinder 5f and is discharged to the outside.

The cylindrical body 14 is formed by fixing or connecting the hole cylindrical portion 5f having the fine holes to the cylindrical non-porous cylindrical portion 5c by a known technique, or the outer peripheral portion or the inner peripheral portion of the fine holes has a predetermined width The non-porous cylindrical portion 5c may be provided around the periphery.

FIG. 4 is a vertical cross-sectional side view of the screen of another embodiment 1. The screen 5a is a cylindrical body 14a having a large number of fine holes, flanges 15 and 16 connected to the front and back of the cylindrical body 14a, and a cylindrical body 14a. An outer cylinder 17 is provided around the outer periphery of the housing. The flanges 15 and 16 are attached to the front and rear frames 3 and 4 respectively. The outer cylinder 17 has an opening larger than the fine hole provided in the cylindrical body 14a.

The outer cylinder 17 is constituted by a non-porous cylindrical portion 5ac not having an opening with a predetermined width Ws on the start end side (right side in the drawing) and a hole cylindrical portion 5af having an opening. In the present embodiment, the outer cylinder 17 is formed of a punching metal having a large diameter. With regard to the undiluted solution in the filtration chamber 13, solid-liquid separation is not performed in the non-porous cylindrical portion 5ac, and the water permeated from the fine holes of the cylindrical body 14a is discharged to the outside from the opening of the outer cylinder 17 in the hole cylindrical portion 5af.

It is necessary to be a thin plate in order to make fine holes, and if the outer cylinder 17 is provided around the thin plate cylindrical body 14a, the outer cylinder 17 becomes a strength member, and damage to the cylindrical body 14a can be prevented.

FIG. 5 is a vertical cross-sectional side view of a screen according to another embodiment 2, in which an outer cylinder 17a is formed by combining small diameter round bars or plate-like members. An opening between the members is a hole cylindrical portion 5af, and the non-porous cylindrical portion 5ac is provided around the outer peripheral portion of the cylindrical body 14a. An outer cylinder 17a is provided around the outer periphery of the cylindrical body 14a as a strength member, and a non-perforated cylindrical portion 5ac having a predetermined width Ws from the start end side and a perforated cylindrical portion 5af for discharging water transmitted from the cylindrical body 14a to the outside If it has, it can implement as the outer cylinder 17a of this invention.

The screens 5 and 5a may be divided into a plurality of parts in the axial or circumferential direction so that they can be easily attached to and detached from the frames 3 and 4.

The stock solution is supplied to the filtration chamber 13 of the screw press 1 through the supply pipe 9 by a supply device (not shown). The supply pipe 9 is connected to the start end wall of the filtration chamber 13, and the undiluted solution is supplied to the non-porous cylindrical portion 5 c of the screen 5 in the filtration chamber 13. Since the start end of the screw blade 6 has a distance from the start end wall of the filtration chamber 13 by the predetermined gap Ls, the screw blade 6 does not inhibit the stock solution supply.

The stock solution immediately after being supplied to the non-porous cylindrical portion 5c of the screen 5 is not subjected to solid-liquid separation. The undiluted solution in which solid-liquid separation is not performed retains water and is in a state of high fluidity. The stock solution supplied in the axial direction from the supply pipe 9 is pressed by the supply pressure and the stock solution sequentially supplied, and moves the non-porous cylindrical portion 5c to the discharge side. That is, it reaches the beginning of the screw blade 6 while maintaining the flowability of the stock solution only by the press-in pressure. The stock solution is not deposited in the vicinity of the start end wall of the filtration chamber 13, and the recovery rate of the stock solution is improved.

The non-porous cylindrical portion 5c of the screen 5 has a width Ws of about 1 to 2 times, preferably about 1 to 1.5 times the gap Ls between the front end of the screw blade 6 and the front end wall of the filtration chamber 13 . Since the non-porous cylindrical portion 5c of the screen 5 has a sufficient length to reach the start end of the screw blade 6, even a low-flowing undiluted solution can easily reach the start end of the screw blade 6. Thereafter, the undiluted solution taken into the leading end of the screw blade 6 is conveyed to the discharge side, and solid-liquid separation is performed in the hole cylindrical portion 5 f of the screen 5.

The width Ws of the non-perforated cylindrical portion 5c of the screen 5 has only the minimum necessary length for scraping off the stock solution at the beginning of the screw blade 6. Therefore, the length of the hole cylindrical portion 5f in the subsequent stage can be made sufficiently long without greatly extending the screen 5. Since the filtration area can be sufficiently secured, the overall length of the screw press 1 does not increase.

Even the highly concentrated undiluted solution with poor dewaterability is taken in from the leading end of the screw blade 6 while maintaining the fluidity, so the undiluted solution can be easily filled in the spiral path of the screw blade 6. Since the undiluted solution is filled substantially uniformly over the entire circumference of the screw blade 6, the filtrate is uniformly discharged from the cylindrical screen 5, and the dewatering efficiency is improved.

Generally, the screw press 1 press-feeds the stock solution, and solid-liquid separation is performed while the filtration chamber 13 is filled with the stock solution. An internal pressure due to the undiluted solution is generated in the filtration chamber 13. By attaching the outer cylinder 17, 17a to the screen 5a, it is possible to increase the strength of the screen 5a. In addition, by providing the non-porous cylindrical portion 5ac in the outer cylinders 17 and 17a, the length adjustment of the non-porous cylindrical portion 5ac becomes easy.

The screen of the screw press according to the present invention is particularly useful when dewatering a low-flowing stock solution, for example, a high-concentration undiluted sewage stock solution or paste-like organic waste with poor dewaterability, or a stock solution rich in incompressible inorganic substances. Play a great effect.

DESCRIPTION OF SYMBOLS 1 screw press 5, 5a screen 5c, 5ac non-perforated cylindrical part 5af hole cylinder part 6 screw blade 7 screw shaft 9 supply pipe 13 filtration chamber 14a cylindrical body 15 flange 16 flange 17 outer cylinder Ls gap Ws width

Claims (3)

A screw shaft (7) having a screw blade (6) wound around the inside of the screen (5, 5a) is rotatably installed to form a filtration chamber (13), and supplied from one end side of the filtration chamber (13) In the screw press (1), which transports the undiluted solution to the other end while dewatering and discharges the dewatered cake,
A feed pipe (9) connected to the beginning end wall of the filtration chamber (13),
A screw blade (6) having a predetermined gap (Ls) between the start end of the screw blade (6) and the start end wall of the filtration chamber (13);
And a screen (5, 5a) having non-perforated cylindrical portions (5c, 5ac) not having fine holes of a predetermined width (Ws) on the start end side.
The width (Ws) of the non-porous cylindrical portion of the screen is 1 to 1.5 times the gap (Ls) between the start end of the screw blade (6) and the start end wall of the filtration chamber (13) The screen of the screw press according to claim 1.
The screen is
A cylinder (14a) having a large number of fine holes;
Flanges (15, 16) connected to the front and back of the cylindrical body (14a),
And an outer cylinder (17) provided around the outer periphery of the cylindrical body (14a),
The outer cylinder (17) is characterized by comprising a hole cylinder portion (5af) having an opening larger than the fine holes and a non-hole cylinder portion (5ac) not having an opening of a predetermined width (Ws). The screen of the screw press according to claim 1 or 2.

Images