JPS5955327A - Method and device for vacuum filtration - Google Patents

Abstract

PURPOSE:To prevent cakes from producing cracks, by interposing a net to the middle of the thickness direction of the cake on a filter cloth in vacuum filtration. CONSTITUTION:Firstly, a driving drum 2 is rotated to evacuate a vacuum box 12. Next, a slurry to be filtered is poured at a prescribed rate onto the holding side 11b of the horizontal surface 11a of a filter cloth 11. The poured slurry is sucked and dehydrated to form a cake layer 27 on the surface 11a. As the feeding rate of slurry is adjusted so that the thickness of the cake layer 27 is larger than a gap between the cloth 11 and a net 16, the net 16 enters in the layer 27 to move parallelly with the cloth 11. In this case, the net 16 acts on the layer 27 at the same role as that of a iron rod in a reinforced concrete, then the cake layer 27 is reinforced by the net 16, and the crack of cake is never produced even after the sucking dehydration is advanced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for preventing the occurrence of cake cracking in a cake that is suction-dehydrated in vacuum filtration.

Generally, when vacuum filtering non-compressible materials with relatively good filterability, such as resins, gypsum, vulcanizing agents, sulfur, etc., cracks are likely to occur in the cake.

By the way, if cracks occur in the cake during full filtration, air leaks through the cracks, the degree of vacuum does not increase, and the dehydration rate decreases.Furthermore, the washing water that contains 1 tin on the cake surface passes through the cake layer. In addition, the water is attracted to the crevices more frequently, resulting in poor cleaning and uneven cleaning. In addition, maintaining the degree of vacuum requires a large-capacity vacuum pump, which is inconvenient.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a method and apparatus for preventing cracks from occurring in a cake when filtering an incompressible filtrate by vacuum filtration. A method of filtering by interposing a net in the middle of the cake on a filter cloth in the thickness direction, and a method of filtering the cake using a filter cloth. This is a device in which a movable net is provided in a section where cake is adsorbed on a traveling filter cloth that performs filtration, maintaining a constant distance of P9r from the filter cloth surface.

The method and apparatus of the present invention will be explained below with reference to the drawings.

1 and 1 show an apparatus for carrying out the method according to the invention.
Or, it shows an example of the device according to the present invention.
1 is covered with a rubber belt at the end 1/s.

One surface of the rubber belt 1 is provided with a net-like filtration groove (not shown) through which the Kid-filtered liquid flows.

The rubber belt 1 wraps around a drive drum 2 and a rotary drum 3, which are rotationally driven by a drive mechanism (not shown), with the filter grooves on the outer circumferential side, and the upper part is a part 1a whose upper surface runs horizontally in the direction of the arrow. There is.

Around the rubber belt 1, an end 1/s filter cloth 11 is movably provided by winding i+& cloth guide rolls 4゜5.6.7, 8, 9.10, and a horizontal portion 1a of the rubber belt. On the upper surface, the filter cloth 11 is brought into close contact with the filter cloth guide roll 4.5 and has a horizontal portion 11 of the cloth.
a is formed. Also, the horizontal part 1 of the above rubber belt
Below a, there is a box 1 which is in close contact with the lower surface vc of the rubber belt 1, and which dehydrates and suctions the material to be filtered on the upper surface of the filter cloth 11 through holes (not shown) made in the pulsating rubber belt 1.
2 is provided. This vacuum box 12 is divided into sections 14 by vacuum box partition plates 13 in the longitudinal direction.
・It is classified into. These sections 14 are evacuated by a vacuum device (not shown), and the sucked filtrate is discharged through the filtrate outlet 15. Above the horizontal part 11a of the cloth, a coarse end 1/snet 16 for reinforcing the υ cake such as a net-like cloth or wire net is placed on the net guide rolls 17.1B, 19, 20°21. It is provided by winding it. The lower part of this net 16 is a net guide roll 17
．． 18, the upper surface of the horizontal part 11a of the soup stock;
They are arranged to face each other at a predetermined distance apart from each other, except for the end portion 11b on the hook side. A feed box 22 for supplying slurry to be passed through is provided above the end portion llb on the side of the bite. In addition, the reference numeral 23 in the figure indicates the filter cloth 1.
1 to wash the spout l/i, 24 to the cake and net 1
Knob 1/I for cleaning 6, 25.26 is Sufu 1 Nopa.

Next, the filtration method and the operation of the vacuum filtration device using the device having the above-mentioned VC structure will be explained.

First, the drive drum 2 is driven to rotate, and the co-shelf box 12 is completely pulled out. Next, the slurry to be filtered is poured at a predetermined speed onto the grip side 11b of the horizontal surface of the cloth d.

The poured slurry is dehydrated by suction, and the horizontal surface of the filter cloth 111
Cake J@27 is formed on top. The amount of slurry in this cake layer 27 is adjusted so that it is thicker than the distance between the filter cloth 11 and the net 16, so that the net 16 runs parallel to the filter cloth 11 which is placed in one layer of slurry. In this case net 16
Since the net 17 acts on the cake layer 27 in the same way as the reinforcing bars of the reinforced concrete 17), the cake layer 27 is strengthened by the net 16, and even if the cake is suction-dehydrated, the cake will not crack. Therefore, the cake layer 27 is uniformly suction-dehydrated, the degree of vacuum is not lowered due to leakage, the cake is evenly washed, and the capacity of the Shinzen pump used for wall pulling is also large. There is no decoration.

Moreover, FIG. 3 and FIG. J show the present invention applied to a cylindrical rotary vacuum filter, and the reference numeral 31 in the figures is a stock solution tank. The stock solution slurry in the stock solution tank 31 is agitated by an agitator 32 to prevent sedimentation. In the stock solution tank 31, a rotationally driven vacuum drum 33 has a lower part connected to the stock solution slurry IC.
Retail placed by dipping. A filter cloth 37 of one end is wound around this Jc drum 33 and filter cloth guide rolls 34, 35, and 36. In addition, on the surface of the portion 37a where the cake I@27 is formed, including the portion in the stock solution tank 31 of the cloth 37, a net guide roll 38°39.4
A freely movable net 44 wrapped with 0.41.42.43
are arranged so that some surfaces of the two are in contact with each other. This net 44 moves the position of the net guide roll 38 in the stock solution tank 1 in the front-rear direction (FIG. 3 (horizontal direction of the shaft)), and
When a certain amount of cake is adsorbed onto the surface of the net 44, the net 44 comes into contact with the upper surface of the cake layer, and thereafter the cake is adsorbed to the outside of the net 44. As a result, the sinet 44 is placed in the middle of the cake layer 27 of the filter cloth 37 (21 where the cake layer 27 is shaped like 1).
It is located at a position that maintains a predetermined distance from the surface 37a of the cloth. In addition, the symbols 45 and 46 in the figure are cleaning sprues l/i,
47.48 is Suf 1/-ha. The action of the net 440 of the filter is the same as that of the net 16 of the horizontal vacuum filter shown in FIG. Although the opening of the net varies depending on the material to be filtered, it is usually from small to -θ.

Next, the present invention will be specifically explained with reference to Examples.

In a horizontal vacuum filtration machine that filters, washes, and dehydrates ABS resin slurry, the cake reinforcement net 16 is used as in the past.
In the case of not using a reinforcing net (open eyes!
Table 1 shows the results when using pharyngeal) 16.

As is clear from the table, very good results can be obtained by using reinforcing nets.

As described above, the method and apparatus according to the present invention can prevent the occurrence of cake cracking when performing true wall filtration on an incompressible material to be filtered, resulting in good dewatering efficiency and sufficient water washing of the cake. This method has the advantage that the capacity of the full pump can be reduced.

) 4. Brief description of the drawings Figures 7 to 7 show an example of an apparatus for carrying out the method according to the present invention or an apparatus according to the present invention, and Figure 7 is a side view of a horizontal vacuum filter. Figure 2 is tt-n in Figure 7.
A line view, FIG. 3 is a side view of the cylindrical rotary vacuum filter, and FIG. 3 is a view from IV-N of FIG. 3.

1... End 1/s rubber belt, 1a...
...Rubber belt horizontal portion, 2...Driving drum, 3...Rotating drum A, 4,5.6.7.8.9
．． 10. Curved il & cloth guide roll, 11...filter cloth, 11a...horizontal part of curved filter cloth, 11b...upper end of horizontal part, 12...curved stem in box, 13 ...
...Partition plate, 14...Four compartments, 15...Filtrate extraction port, 16...Curved sleeve strong net (net), 17.18
．． 19.20.21...Honet guide roll, 22...
... Feed box, 23.24 ... Washing soap 1 noi, 25.26 ... Washing cloth 1 nopa, 27 ... Cake layer, 31 / Song / Undiluted solution Tank, 32
・・Song agitator, 33・・・・Drums, 34
．． 35°36...Filter cloth guide roll, 37...
... Filter cloth, 37a ... Part of filter cloth where cake is adsorbed, 38° 39.40.41.42.43.
・Song net guide roll, 44・・Song reinforcement net (net), 45.46・・・・Sufu 1 Noi, 47.48・
...Sc 1/-P Fig. 3 Fig. 4 = 164

Claims (2)

[Claims] (1) A vacuum filtration method characterized in that a net is interposed in the middle in the thickness direction of a cake formed on the surface of a filter cloth by filtration. (2) A vacuum filtration device characterized in that a movable net that maintains a predetermined distance from the filter cloth surface is provided in a section where the vacuum filtration device adsorbs cakes on a cloth in which the vacuum filtration device travels.