JPH07124417A - Vacuum filter - Google Patents

Abstract

PURPOSE:To provide a small sized vacuum filter at a low cost with which effective filtration and dehydration can be performed by evacuating plural vacuum boxes at respective optimum timing in the vacuum filter which is provided with plural vacuum boxes parallelly and stationarily and also with an endless filter cloth traveling on the upper part of these vacuum boxes intermittently. CONSTITUTION:In this vacuum filter, the vacuum box 7A is connected to the vacuum tank 12 through the supply section three-way valve 71A and similarly, the vacuum boxes 7B, 7C, 7D and 7E are connected to the vacuum tank 12 through the supply section three-way valves 71B, 71C, 71D and 71E respectively. The supply section three-way valve 71A is operated at its own timing differntly from that of each of the other three way-valves 71B, 71C, 71D and 71E by using the control circuit 15.

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. The present invention relates to a vacuum filtration device that is arranged in parallel with each other and is provided with an endless filter cloth that intermittently travels above the vacuum boxes, and that supplies an object to be processed to the endless filter cloth.

[0002]

2. Description of the Related Art A plurality of vacuum boxes are fixedly arranged side by side, and an endless filter cloth which intermittently runs on the upper part of these vacuum boxes is provided and an object to be treated is supplied to the endless filter cloth. As a vacuum filtration device,
There is a filtering device disclosed in Japanese Patent Publication No. 9564. In the apparatus of this publication, as shown in FIG. 6, a plurality of vacuum boxes 101, 102, 103 are fixedly arranged side by side, and an endless filter cloth 10 which runs intermittently above the vacuum boxes is provided.
4 shows an example of a vacuum filtration device configured to supply an object to be processed to the endless filter cloth 104. However, when the pressure in each vacuum box is reduced at the same time, if there is a portion of the filter cloth above the vacuum box that is not covered by the object to be processed, vacuum leakage occurs and a high degree of vacuum cannot be obtained.
Therefore, in the device of Japanese Patent Publication No. 5-69564, the vacuum box 101 is connected to the opening / closing valves 101a and 101b and the vacuum tank 101C, and the vacuum box 102 is connected to the opening / closing valve 10
2a and 102b are connected to the vacuum tank 102C, and the vacuum box 103 is connected to the on-off valves 103a and 103b and the vacuum tank 103C. The timing of depressurizing each vacuum box is configured to be different by independently controlling each on-off valve.
According to such an apparatus, it is possible to depressurize each vacuum box at an optimum timing and perform effective filter dehydration.

[0003]

[Problems to be Solved by the Invention] However, Japanese Patent Publication No. 5-6
According to the technology of Japanese Patent Publication No. 9564, as shown in FIG. 6, the same number of vacuum tanks as the number of vacuum boxes, and in the case of FIG. 6, three vacuum tanks are required, so that the size of the apparatus becomes large. There are problems and the cost of the device increases.

Therefore, an object of the present invention is to provide an apparatus capable of effectively depressurizing a plurality of vacuum boxes at optimum timings for effective filtration and dehydration, which is small in size and low in cost. It was made.

[0005]

In a vacuum filtration device according to the present invention, a plurality of vacuum boxes are fixedly arranged side by side, and an endless filter cloth running intermittently above the vacuum boxes is provided. In a vacuum filtration device provided with a supply means for supplying an object to be processed above the endless filter cloth,
A means for connecting the plurality of vacuum boxes to a single vacuum tank via individual opening / closing valves and providing a control means for controlling opening / closing of one of the opening / closing valves at different timings has been taken.

[0006]

In the present invention, the endless filter cloth which runs intermittently is provided on the upper part of the plurality of fixedly arranged vacuum boxes, and the slurry or the like is covered from the supply means provided above the filter cloth. By supplying the processed material and depressurizing the vacuum box, the processed material supplied on the filter cloth is filtered and dehydrated.

At this time, since the plurality of vacuum boxes are connected to a single vacuum tank via respective individual open / close valves, the control means opens / closes one of the open / close valves at different timings. By controlling, each vacuum box can be decompressed at an optimum individual timing.

Therefore, after the material to be supplied covers the filter cloth,
By reducing the pressure of the vacuum box, a high degree of vacuum can be obtained without causing vacuum leakage. Further, each vacuum box is connected to a common single vacuum tank, but since the open / close valves are independent of each other, the above-mentioned control is possible.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the 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 this filter cloth 1 is
It is an endless type that is wound around a driving drum 2 and a plurality of (five in FIG. 1) driven rollers 3A, 3B, 3C, 3D, 3E, and runs intermittently by the driving drum 2. Is driven to. 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 unit 7A, 7B, 7C, 7D, 7E vacuum dehydration. Parts are formed. The width of these vacuum boxes is the same as the travel distance L1 of the filter cloth 1 that travels intermittently. The travel distance L1 per time is set to be shorter than the width L2 of the filter cloth 1. That is, as shown in FIG.
7A, 7B, 7C, 7D and 7E are 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 has a width of one travel distance L1 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 a tension tension device for adjusting the tension of the filter cloth 1.
Ten are provided.

The supply section 4 is provided with a supply box 4B which is reciprocally movable along a rail 4A arranged at right angles to the running direction of the filter cloth 1 and at a right angle to the running direction of the filter cloth 1. A cylinder device 4C that reciprocally drives the box 4B is provided. The moving speed of the supply box 4B is set so that it can be reciprocated a predetermined number of times within the stationary time of the filter cloth 1. The supply box 4B is connected to a supply pipe of the stock solution slurry through a flexible hose 4D, and a stirring mechanism 4E that stirs the supplied stock solution slurry so as to spread uniformly in the running direction of the filter cloth 1 and the running direction. And a chute 4F for dropping the uniformly spread slurry onto the filter cloth 1.

The vacuum box 7A is connected to the vacuum tank 12 via the supply section three-way valve 71A, and the vacuum box 7B is connected to the three-way valve 71A.
Connected to the vacuum tank 12 via B, the vacuum box 7C connected to the vacuum tank 12 via the three-way valve 71C, the vacuum box 7D connected to the vacuum tank 12 via the three-way valve 71D,
The vacuum box 7E is connected to the vacuum tank 12 via a three-way valve 71E. The three-way valves 71A, 71B, 71C, 71D, 71E can be individually operated by the control circuit 15 at different timings as shown in FIG. 5, and each vacuum box can be depressurized to a different degree of vacuum. Is configured.

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 which collects the water that has permeated the filter cloth 1 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, there is a pneumatic or hydraulic drive mechanism 6A and the drive mechanism. A press member 6B which is driven up and down by a mechanism 6A, a rubber belt 6C are arranged, and a reinforced punching metal (not shown) 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 configuration is as follows: a predetermined time T while the filter cloth 1 is stationary.
(For example, 30 seconds) is the time t during the running of the filter cloth 1 after the slurry supply, vacuum dehydration, pressure dehydration, and filter cloth cleaning are performed.
In the operation, the slurry is continuously supplied, but 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. Naturally, the traveling speed of the filter cloth 1 is set as high as possible (for example, 2 m / min to 10 m / min) in order to increase the operating rate.

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 the supply box 4B is moved once by the cylinder 4C in the direction perpendicular to the traveling direction of the filter cloth 1, that is, after the filter cloth 1 is covered with the slurry, the supply section three-way valve 71A is switched to the suction side. Then, the inside of the vacuum box 7A is depressurized, and the slurry on the filter cloth 1 is vacuum dehydrated. Therefore, a thin cake layer is formed on the filter cloth 1. Depending on the type of slurry, even before the supply box 4B has finished moving once, it can be dispersed evenly on the surface of the filter cloth 1, so the three-way valve 71A can be sucked without waiting for the movement to complete once. You may switch to the side. The timing of switching the supply unit three-way valve 71A to the suction side can be determined only by the elapsed time because the moving speed of the supply box 4B is known, but a limit switch for detecting the movement of the supply box 4B can be used. Alternatively, the number of movements may be confirmed by a counter or the like. Further, as shown in FIG. 5, the limit switch may be checked after a predetermined time has elapsed, and then the switching may be performed. On the cake layer thus formed, the slurry is sequentially supplied from the reciprocating supply box 4B while being dehydrated, so that a plurality of thin cake layers are laminated. The supply box 4B may reciprocate from the central portion of the filter cloth 1 to the left and right. At this time, the slurry hardly spills from the filter cloth 1.

Then, after a predetermined rest time T, for example,
After the two reciprocations have been completed or immediately before that, the filter cloth 1 is caused to travel a predetermined travel distance L1. 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 in each vacuum box and running for a predetermined distance L1 and standing still, immediately switch each of the three-way valves 71B, 71C, 71D, 71E other than the supply section three-way valve 71A to the suction side to decompress each vacuum box. Begin to. The supply part three-way valve 71A of the supply part 4 is slightly delayed as described above. Since it is not necessary to form the cake layer into four complete layers, the slurry is continuously supplied while the filter cloth 1 is running. Supplying filter cloth 1 to 2 boxes 4B
When the filter cloth 1 is run just before the end of the reciprocation, the slurry is supplied from the end to the next part of the filter cloth 1, and the vacuum leak is small.

The four cake layers moved to the vacuum box 7B are further vacuum dehydrated by the vacuum box 7B having a higher vacuum degree than the vacuum box 7A. At this time, in the supply unit 4, as described above, a new thin cake layer is laminated on the filter cloth 1. Then, again after the predetermined rest time T has elapsed, the filter cloth 1 travels the predetermined travel distance L1. 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 travels after the elapse of the predetermined rest time T, the cake layer after washing 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 driving 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 running 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, a plurality of cake layers are laminated and formed by the supply box which reciprocates in the direction perpendicular to the running direction of the filter cloth 1. At the same time, in the cake washing section 5, the active ingredients in the laminated cake layers are sufficiently washed out and collected. Further, in parallel, the water content of the cake is sufficiently dehydrated in each vacuum box of the vacuum dehydration unit. Further, in parallel, in the pressure dehydration unit 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 device of the above-described embodiment, the depressurization timings of the respective vacuum boxes are not the same, and only the vacuum box 7A of the supply unit 4 is supplied to the supply box 4B.
Is moved once, that is, after the slurry covers the filter cloth 1, the pressure is reduced, so that there is little vacuum leakage and a high degree of vacuum is obtained. Further, since each vacuum box is decompressed at a predetermined timing and a predetermined degree of vacuum by using a single vacuum tank, a vacuum tank or a suction blower for each vacuum box is unnecessary, and the size of the apparatus can be reduced. Along with
Cost can be reduced.

Further, the running distance L1 per one time of the filter cloth 1
However, in the vacuum filtration device shorter than the width L2 of the filter cloth 1, by supplying the slurry while reciprocating the supply box 4B in the width direction of the filter cloth 1, the supplied slurry is uniformly dispersed and spread, Since it is easy to form a uniform cake layer, a thin portion of the cake is unlikely to occur, and a sufficiently high degree of vacuum can be obtained. Therefore, the effect of vacuum dehydration is improved, and a cake having a lower water content can be obtained. Further, since the supply box 4B may be of the same size regardless of the width of the filter cloth of the vacuum filtration device, common parts are achieved regardless of the size of the device, and manufacturing and management of parts, In addition, the effect that maintenance can be performed efficiently can be obtained. In addition, since the cake on the filter cloth 1 is made uniform even in the cake cleaning unit 5, the sprayed cleaning water easily permeates into the cake layer to uniformly wash the cake and effectively The components can be thoroughly washed out and recovered.

Since the filter cloth cleaning device 9 cleans the filter cloth 1 while reciprocating in the running direction of the filter cloth 1 while the filter cloth 1 is stationary,
The effect that sufficient cleaning time can be obtained is obtained.

Instead of the three-way valves, two on-off valves may be used in combination. A pressure reducing valve may be provided together with each three-way valve. Further, at least only the supply part three-way valve 71A needs to be controlled at a different timing from the other three-way valves. Although the supply box 4B is reciprocated in the width direction of the filter cloth 1 in the above embodiment, it may be reciprocated in the length direction, and the tip of the supply pipe may be provided without providing the supply box 4B. You may reciprocate. 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. The filter cloth cleaning device 9
May be reciprocated in the width direction of the filter cloth 1.

[0027]

According to the vacuum filtration device of the present invention,
Optimum for each vacuum box because multiple vacuum boxes are connected to a single vacuum tank via individual open / close valves and one of the open / close valves is opened / closed by the control means at different timings. The pressure can be reduced at individual timings. Therefore, by reducing the pressure of the vacuum box after the material to be supplied has been covered on the filter cloth, a high degree of vacuum can be obtained without causing vacuum leakage, and an excellent filter dehydration effect can be obtained. Further, since only one vacuum tank is required for a plurality of vacuum boxes, the size of the vacuum filtration device can be reduced and the cost can be reduced.

[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 flow chart illustrating the operation of the present invention.

FIG. 6 is a diagram showing a configuration of a conventional example.

[Explanation of symbols]

 1 filter cloth (endless filter cloth) 2 driving drum (driving device) 4B supply box (supply port of material supply means) 7A, 7B, 7C, 7D, 7E vacuum box 71A supply section three-way valve (open / close valve) 71B, 71C, 71D, 71E Three-way valve (open / close valve) 12 Vacuum tank 15 Control circuit (control means)

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hideo Yoshikawa 916-1 Mitsugi, Musashimurayama City, Tokyo

Claims (1)

[Claims] 1. A plurality of vacuum boxes are fixedly arranged side by side, and an endless filter cloth which intermittently runs on the upper part of these vacuum boxes is provided, and an object to be treated is supplied above the endless filter cloth. In the vacuum filtration device provided with a supply means for connecting the plurality of vacuum boxes to a single vacuum tank via respective open / close valves, and opening / closing one of the open / close valves at different timings. A vacuum filtration device comprising a control means for controlling.