JPH07213813A - Vacuum filter - Google Patents

Abstract

PURPOSE:To continuously feed a slurry while a filter cloth travels or stops, to feed the slurry onto the filter cloth with uniform thickness, to make the filtration speed high and also to reduce the fluctuation of water content. CONSTITUTION:A feeding box 4B is controlled by a controller 4C so that the feeding box may move at a speed of 1m/min in the opposite direction to the travelling direction of a filter cloth 1 while filter cloth 1 stops and may run after the filter cloth at a speed of 4m/min while the filter cloth 1 travels at a speed of 5m/min. The relative speed of the feeding box 4B to the filter cloth 1 is fixed 1m/min, both when it moves forward and backward.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum filtration device for filtering and dehydrating a slurry-like object to be processed in chemical industry, mining industry, food factory, etc., and particularly to a filter cloth to which the slurry is supplied. The present invention relates to a device configured to intermittently travel and vacuum filter.

[0002]

2. Description of the Related Art A method for filtering a slurry on a filter cloth by intermittently running the filter cloth is disclosed in Japanese Patent Publication No. 5-69564.
There is a filtration method and device disclosed in the publication. This technique is a horizontal vacuum filtration method in which an object to be treated such as a slurry is intermittently supplied onto a filter cloth running in one direction, vacuum suction is performed to form a cake, and dehydration and filtration are performed. As shown in FIG. 2, a supply port 101 of a slurry supply means is provided above the filter cloth which is intermittently driven by a drive device, and the supply port 101 is provided so as to be movable in the length direction of the filter cloth 102. It is a filtering device having a configuration.

With this, a plurality of layers of the slurry are formed to make the thickness of the cake uniform.

[0004]

[Problems to be Solved by the Invention] However, Japanese Patent Publication No. 5-6
According to the technique of Japanese Patent Publication No. 9564, the slurry is supplied by a predetermined supply method while the filter cloth is stationary, but since the slurry flows down without stopping the supply even while the filter cloth is running, the slurry is fed while the filter cloth is running or stationary. At, since the moving speed of the supply port with respect to the filter cloth changes,
The uniformization of the cake thickness was insufficient.

Further, since the slurry is supplied again onto the slurry on the filter cloth, the filtration rate cannot be increased.

In view of the above, the present invention provides a vacuum filtration device configured to intermittently run a filter cloth to vacuum-filter the slurry supplied onto the filter cloth, whether the filter cloth is running or stationary. The purpose of the present invention is to provide a vacuum filtration device in which the slurry is continuously supplied and the slurry is supplied on the filter cloth in a uniform thickness to increase the filtration rate and to reduce the variation in the water content.

[0007]

In a vacuum filtration device according to the present invention, an endless filter cloth which is intermittently run by a drive device is provided on an upper part of a vacuum box fixedly arranged, and the endless filtration device is provided. In a vacuum filtration device provided with a supply means for supplying an object to be processed above a cloth, a moving means for reciprocating a supply port of the supply means in a traveling direction of the endless filter cloth, and an endless filter cloth running. And a movement control means for moving the supply port in the traveling direction at a speed lower than the traveling speed of the endless filter cloth, and for moving the supply port in a direction opposite to the moving direction when the endless filter cloth is stationary. I took steps to prepare.

[0008]

In the present invention, the moving means reciprocates the supply port of the supplying means in the running direction of the endless filter cloth, and the movement control means allows the endless filter cloth to move endlessly while the endless filter cloth is running. When the endless filter cloth is stationary, the supply port is moved in the running direction at a speed slower than the running speed of the filter cloth.
Since the supply port is configured to be moved in the direction opposite to the moving direction, the endless filter cloth can be moved in one direction when the endless filter cloth is running and when the endless filter cloth is stationary. The object to be processed is supplied to a range corresponding to the traveling distance.

When the relative moving speed of the supply port with respect to the filter cloth while the endless filter cloth is running is equal to the moving speed of the supply port when the endless filter cloth is stationary, the supplied object is treated as an endless filter cloth. Supplied evenly on top.

As described above, the speed conditions for uniformly supplying the endless filter cloth will be examined in detail below. In FIG. 5, the stationary time T per endless filter cloth,
Running time per endless filter cloth t, moving speed x of the supply port while the endless filter cloth is stationary, moving speed y of the supply port while the endless filter cloth is running, travel distance per endless filter cloth L,
The running speed of the endless filter cloth can be expressed as L / t.

Here, the supply port moves in the direction opposite to the running direction of the filter cloth at the moving speed x while the endless filter cloth is stationary, and moves at the moving speed while the endless filter cloth is running. With y, it moves in the same direction as the running direction of the filter cloth. However, y <L / t. Here, since the relative moving speed of the filter cloth and the supply port is L / t-y while the filter cloth is running, this is equal to the moving speed x of the supply port when the filter cloth is stationary. Therefore, x = L / ty must be satisfied.

The range of supply of the filter cloth while it is stationary is x
・ T, and the range that the filter cloth supplies while running is (L / t
-Y) · t, and the sum of the two must be equal to the running distance L per filter cloth, so that x · T + (L / t−y) · t = L must be established. .

∴x · T = y · t ... That is, if the moving speed and the time are set so that the relationship of the above equation holds, the relative speed becomes constant. The following are examples of specific numerical values. For example, the running time per endless filter cloth is t = 0.1 min, the moving speed x of the supply port when the endless filter cloth is stationary is 1 m / min, and the moving speed of the supply port when the endless filter cloth is running is y = 4 m. / Min, and the running distance per endless filter cloth L = 0.5 m, T = 0.4 min from the above formula.

That is, while the filter cloth is stationary, the feed port moves at a speed of 1 m / min for 0.4 min and then, as the filter cloth runs, at a speed of 4 m / min in the opposite direction, 0.1 min It will be good if you move.

In this way, by controlling the moving speed of the supply port, the relative moving speed of the supply port can be made constant within the range corresponding to the travel distance per time. It is possible to evenly supply the product.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a vacuum filtration device according to the present invention will be described below with reference to FIGS. 1, 2, 3, 4, and 5. In the figure, reference numeral 1 is a filter cloth, and the filter cloth 1 is wound around a driving drum 2 and a plurality of (five in FIG. 1) driven rolls 3A, 3B, 3C, 3D, 3E. It is of an endless shape and is driven by the drive drum 2 so as to travel intermittently.

Above the horizontal portion 1A of the filter cloth 1, a supply unit 4, a cake cleaning unit 5 and a pressure dehydration unit 6 are formed, and below the vacuum boxes 7A, 7B, 7C, 7D, 7E. A vacuum dehydration unit is formed. The width of these vacuum boxes is the same as the travel distance L of the filter cloth 1 that travels intermittently. In addition, the traveling distance L per time
Is set shorter than the width of the filter cloth 1. That is, as shown in FIG. 4, each vacuum box 7A, 7B, 7C, 7D, 7E
Is formed in a rectangular shape that is long in the width direction of the filter cloth 1.

A scraper 8 for scraping off the cake on the filter cloth 1 is provided in the vicinity of the drive drum 2. Further, a filter cloth cleaning device 9 for cleaning the filter cloth 1 is provided between the drive drum 2 and the driven roll 3A in the vicinity of the filter cloth 1. This filter cloth cleaning device 9
In the above, the cleaning water from the cleaning water tank is supplied to the cleaning nozzle 9C via the solenoid valve 9A and the flexible hose 9B. In addition, the filter cloth cleaning device 9 is a portion having a width of one travel distance L per one movement of the filter cloth 1 while reciprocating along the traveling direction of the filter cloth 1 by the cylinder 9D while the filter cloth 1 is stationary. Is configured to be washed.

The driven roll 3B is provided with a tensioning device 10 for adjusting the tension of the filter cloth 1.

Next, the detailed structure of the supply unit 4 will be described.
The supply unit 4 is a rail arranged in the traveling direction of the filter cloth 1.
A supply box 4B that can reciprocate in the traveling direction of the filter cloth 1 along 4A, a cylinder device 4C that reciprocally drives the supply box 4B, and a control device that controls the operating direction and operating speed of the cylinder device 4C. It is equipped with 4G. A signal relating to the rotation / stop of the drive drum 2 is input to the control device 4G.

The rail 4A and the cylinder device 4C constitute a moving means, and the control device 4G constitutes a movement control means. In this control device 4G, the running time of the filter cloth 1 per time is t and the stationary time is T, the running distance per time is L, and the moving speed of the supply port when the endless filter cloth is stationary is x. , When the moving speed of the supply port while the endless filter cloth is running is defined as y, the moving speed and time are set so that the relative speed becomes constant so that the relationship of x · T = y · t is established. To control.

Therefore, the running time per filter cloth t = 0.
1 min, moving speed of supply port x = 1 m / mi when filter cloth is stationary
n, the moving speed of the supply port while the filter cloth is running, y = 4 m / min,
Assuming that the running distance per filter cloth is L = 0.5 m, T = 0.
It will be 4 min. That is, in the control device 4G, while the filter cloth is stationary, the supply port is 0.4 m at a speed of 1 m / min.
It is set so that it moves n times and then moves 0.1 min at a speed of 4 m / min in the opposite direction as the filter cloth runs. At this time, the running speed of the filter cloth is 5 m.
(= 0.5 / 0.1).

The supply box 4B is connected to a stock solution slurry supply pipe via a flexible hose 4D, and a stirring mechanism 4E for stirring the supplied stock solution slurry so as to spread uniformly in the width direction of the filter cloth 1. , A chute 4F for dropping the slurry uniformly spread in the width direction onto the filter cloth 1.

The vacuum boxes 7A, 7B, 7C, 7D, 7E are connected to vacuum tanks via three-way valves 71A, 71B, 71C, 71D, 71E, respectively. The sucked air and the filtrate are separated into gas and liquid in the vacuum tank. The air in the vacuum tank is sucked by an exhaust blower, and the filtrate is discharged by a drainage pump. As a result, the inside of the vacuum tank is always kept depressurized.

The three-way valves 71A, 71B, 71C, 71D, 71E can be individually operated at different timings, and
Each vacuum box can be depressurized to different degrees of vacuum.

The cake cleaning section 5 is equipped with a cleaning nozzle for cleaning the cake on the filter cloth 1, and sprays the water in the water collecting pit 11 in which the water permeating the filter cloth 1 is collected onto the cake. Thus, the active ingredient of the cake is washed out and collected in the vacuum tank, and the dehydration efficiency is improved.

The pressurizing and dehydrating section 6 pressurizes and dehydrates the cake while the filter cloth 1 is stationary. Above the filter cloth 1, a drive mechanism 6A by air pressure or hydraulic pressure and the drive mechanism are provided. A press member 6B driven up and down by a mechanism 6A and a rubber belt 6C are arranged, and a reinforced punching metal and a vacuum box 7E are arranged below.

As shown in FIG. 4, the general operation of the vacuum filtration device having the above-described structure is as follows:
For example, the moving speed of the supply box is 1 m / min for 0.4 minutes.
The slurry is supplied while moving at a speed of, and vacuum dehydration, pressure dehydration, and cleaning of the filter cloth are performed. The supply range during rest is 0.4 m (= 0.4 × 1). Then, for 0.1 minute while the filter cloth 1 is running, the supply box moves at a moving speed of 4 minutes.
Traveling speed is 5m / min by moving at m / min
Relative speed 1m / min (= 5-
Continue to supply the slurry while moving at the speed of 4). The supply range during traveling is 0.1 m (= 0.1 x 1). At this time, the vacuum is released, the press of the pressure dehydration unit rises, the cleaning of the filter cloth is stopped, and the dehydrated cake is scraped off from the filter cloth 1.

Further, the operation of this vacuum filtration device will be described in detail. First, the stock solution slurry supplied to the supply unit 4 is
It is spread by the stirring mechanism 4E so as to be dispersed in the width of the chute 4F, and is supplied onto the filter cloth 1 along the chute 4F. The water content of the slurry on the filter cloth 1 is somewhat dehydrated by gravity dehydration before the vacuum dehydration works.

Then, after a predetermined rest time T, the filter cloth 1 is run for a predetermined running distance L. While the filter cloth 1 is running,
Switch each three-way valve 71A, 71B, 71C, 71D, 71E to the open side,
After releasing the vacuum of each vacuum box and running for a predetermined distance L and standing still, immediately switch each of the three-way valves 71B, 71C, 71D, 71E other than the three-way valve 71A of the supply unit 4 to the suction side to switch each vacuum box. Start depressurizing.

The three-way valve 71A of the supply unit 4 starts depressurizing with a slight degree of vacuum after being slightly delayed from the other three-way valves.

The cake layer that has moved to the position of the vacuum box 7B is further vacuum dehydrated by the vacuum box 7B having a higher degree of vacuum than the vacuum box 7A. And again,
After the elapse of the predetermined rest time T, the filter cloth 1 travels the predetermined traveling distance L. Next, in the cake layer that has moved to the cake cleaning unit 5, the active ingredients and the like are washed out by the cleaning water, fall into the lower vacuum box 7C, and are sucked into the vacuum tank.

Further, when the filter cloth 1 runs after the elapse of the predetermined rest time T, the washed cake layer is sufficiently vacuum dehydrated by the vacuum box 7D having a higher vacuum degree. In this way, the cake that has been sufficiently vacuum dehydrated moves to the pressure dehydration unit 6.

In the pressure dehydration unit 6, the water that could not be dehydrated in the vacuum dehydration unit is further dehydrated to further reduce the water content of the cake. The filtrate in the pressure dehydration unit 6 is
It falls into the vacuum box 7E and is sucked into the vacuum tank together with the air sucked from the portion around the cake on the filter cloth 1.

In this way, the cake having a sufficiently low water content by vacuum dehydration and pressure dehydration is the drive drum 2
In the portion (1), the scraper 8 scrapes off the filter cloth 1 and transfers it by a conveyor (not shown) or the like.

Since the filter cloth cleaning device 9 cleans while reciprocating along the traveling direction of the filter cloth 1 by the cylinder 9D for a predetermined time T while the filter cloth 1 is stationary, a sufficient cleaning effect is obtained. As a result, the clogging time of the filter cloth 1 can be extended, the operating rate of the vacuum filtration device is improved, and the labor of maintenance is reduced.

In this way, in the supply section 4, the cake is supplied by the supply box. At the same time, in the cake washing section 5, the active ingredients in the supplied cake are sufficiently washed out and collected. Furthermore, in parallel,
In each vacuum box of the vacuum dehydration section, the water content of the cake is sufficiently dehydrated.

Further, in parallel, in the pressure dehydration section 6, the water content becomes lower due to the pressure dehydration, and the water content is scraped off by the scraper 8.

As described above, according to the vacuum filtration apparatus of the above-described embodiment, the slurry is continuously supplied by moving the supply box 4B at the same relative speed while the filter cloth 1 is stationary or running. The supplied slurry is always filtered 1
The new part above can be continuously and evenly supplied.
Therefore, the effect that the filtration rate can be increased and the processing capacity per unit time can be increased is obtained.

Further, by supplying the slurry to a uniform thickness, it is possible to obtain an effect that variation in water content can be reduced. When processing a slurry of calcium carbonate with a concentration of 30 wt%, the conventional equipment would be 240 kg DS /
The filtration rate was m · h, but according to this example, 32
It was possible to process at a filtration rate of 0 kg · DS / m · h.

The water content of the cake was 41.2 ±
Although there was a variation of 2.5%, according to this example, it was within a variation of 39.0 ± 1.1%.

In the cake cleaning section 5, the filter cloth 1
Since the upper cake is made uniform, the sprayed washing water easily permeates into the cake to uniformly wash the cake and sufficiently wash out and recover the active ingredient.
In addition, using a single vacuum tank, each vacuum box,
Since the pressure is reduced at a predetermined timing and a predetermined degree of vacuum, a vacuum tank and a suction blower for each vacuum box are unnecessary, and the size of the device can be reduced and the cost can be reduced.

Further, since the filter cloth cleaning device 9 performs cleaning while the filter cloth 1 is stationary while reciprocating in the traveling direction of the filter cloth 1,
The effect that sufficient cleaning time can be obtained is obtained. Further, as the drive source of the supply box 4B, it is sufficient that the cylinder device 4C by air pressure or hydraulic pressure, or a drive mechanism by a rack and pinion equipped with a forward / reverse rotation motor can be reciprocally driven.

[0044]

According to the vacuum filtration device of the present invention,
When the supply port of the supply means is moved back and forth in the running direction of the endless filter cloth, while the endless filter cloth is running, the supply port is moved in the running direction at a speed slower than the running speed of the endless filter cloth, and the endless filter cloth is moved. Is configured to move the supply port in the direction opposite to the moving direction when the filter is stationary, the effect that the filtration speed can be increased by supplying the slurry with a uniform thickness onto the endless filter cloth at one time. Is obtained.

By supplying the slurry to a uniform thickness, it is possible to obtain a cake having a small variation in water content.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of a vacuum filtration device according to the present invention.

FIG. 2 is a side view of a main part of the vacuum filtration device.

FIG. 3 is a perspective view of a main part of the vacuum filtration device.

FIG. 4 is a timing chart illustrating the operation of the vacuum filtration device.

FIG. 5 is a diagram for explaining the operation of the present invention.

FIG. 6 is a diagram illustrating an operation of a conventional example.

[Explanation of symbols]

 1 Filter cloth (endless filter cloth) 2 Driving drum (driving device) 4A Rail (moving means) 4B Supply box (supplying port of supplying means) 4C Cylinder device (moving means) 4G Control device

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kazunori Miura 239-3 Iwasawa, Hanno City, Saitama Prefecture

Claims (1)

[Claims] 1. A vacuum box, which is fixedly provided, has an endless filter cloth which runs intermittently by a driving device, and a supply for supplying an object to be processed above the endless filter cloth. In a vacuum filtration device provided with means, moving means for reciprocating the supply port of the supply means in the running direction of the endless filter cloth, and while the endless filter cloth is running, at a speed slower than the running speed of the endless filter cloth. A vacuum filtration device comprising: a movement control unit that moves the supply port in the traveling direction and moves the supply port in a direction opposite to the moving direction when the endless filter cloth is stationary.