JPS6343123B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small-sized liquid filtration device that can efficiently remove particles in a liquid continuously for a long period of time.

In manufacturing semiconductor devices such as LSI, a round bar-shaped semiconductor material is successively cut into thin pieces to create many thin disk-shaped substrates, and each disk-shaped substrate is divided into many small rectangular sections. After forming a semiconductor element circuit in each section, the semiconductor device is cut and separated into each section. By the way, in this case, cutting is done while pouring water on the cut part, but the water used for cutting contains the
It contains a large amount of semiconductor material chips with a diameter of about 0.3 to 1 μm, and in addition, if the semiconductor substrate material is potassium arsenic, it contains harmful substances and cannot be directly drained.

As a countermeasure, water treatment by coagulation and sedimentation has conventionally been carried out, but this method has drawbacks such as insufficient treatment. Therefore, instead of this, a method using water-resistant filter paper is being implemented, which is easy to process, and has recently seen a remarkable improvement in filtration performance, and which can easily remove fine particles of 0.3 μm or less.
In this method, for example, as shown in Fig. 1a, a paper-like filter medium 1 (hereinafter referred to as filter paper) folded into a corrugated shape is supported in a case 2 so as to form an annular shape, and the to-be-treated water is This is a so-called cartridge method in which the liquid is filtered through a filter. Another example is a filter paper 1 rolled up into a roll, as shown in FIG.
In this method, a part of the filter paper 1 is placed in a water passage section, and when cutting debris accumulates there, the filter paper 1 is wound up on a roll 3, and filtration is always performed using a new filter paper.

These methods are easier to operate than conventional coagulation-sedimentation methods and are significantly superior in filtration performance. However, in these methods, the filtration efficiency decreases due to the thinness of the filter paper used for filtration, that is, most of the cutting debris 4 trapped on the surface as shown in FIG.
A common drawback is that the expected filtration performance cannot be obtained because some of the cut debris with a diameter smaller than the ventilation pores of the filter paper 1 comes out through the filter paper 1 to the drainage side due to water pressure, reducing the filtration efficiency. There is. In addition, in the method shown in Figure 1a, that is, the cartridge method, the filter paper 1 is folded into a corrugated shape to increase the filtration volume, but the filtration volume obtained is still small, so it is often Cartridge must be replaced. For this reason, not only cannot continuous filtration be performed for a long period of time, but also troublesome replacement work is required, which increases the manufacturing cost of the semiconductor device.

The present invention has been made for the purpose of providing a compact liquid filtration device that can perform continuous filtration work for a long time while maintaining high filtration efficiency that eliminates the drawbacks of the conventional methods. The details will be explained using drawings.

The features of the present invention are as follows. That is, in the present invention, as shown in the plan view of FIG. 2 or FIG. At the same time, the water to be treated is passed from the inner circumferential surface to the outer circumferential surface in the direction of the outer circumferential surface as shown by arrow A to perform filtration. establish. and filter cylinder 5
The inner diameter of the filter drum 5 and the outer diameter of the winding shaft 6 are adjusted such that an inflow space for the water to be treated is always created between the filter drum 5 and the winding shaft 6 on which the filter paper is wound. While filtering the water to be treated by passing it from the peripheral surface to the outer peripheral surface, when cutting waste 4 accumulates on the inner peripheral surface and the water flow pressure increases, the winding shaft 6 is used to leave a backup filtration layer F at the end. The filter paper 1 is characterized in that the filter paper 1 is wound up for the portion where cutting waste is accumulated, that is, for one layer.

Note that the example in FIG. 2 shows the cavity 5 of a fixed filter cylinder 5.
A winding shaft 6 that can be rotated is provided at the center of a, and at the same time, a pressure contact piece 8 that obtains pressure contact force by a spring body 7 prevents the winding of the filter paper 1 in the filter cylinder 5 from loosening. Winding is performed while regulating the position of the filter paper delivery section. Further, in the example shown in FIG. 3, the winding shaft 6 is provided so as to be pressed against the inner peripheral surface of the filtration drum 5 by a spring body 9, and by rotating the filtration drum 5, the winding shaft 6 is brought into contact with the inner peripheral surface of the filtration drum 5. The filter paper 1 is wound up by utilizing the friction between it and the take-up shaft 6 without loosening the winding.

A filter cylinder 5 in which filter paper 1 is wound in multiple layers as in the present invention
If filtration is performed by filtration, the cutting debris 4 that has passed without being captured by the first layer of filter paper will accumulate on the surface of the second layer of filter paper, and the debris that has passed without being captured will be deposited on the surface of the second layer of filter paper. Captured by 3 layers.
Then, capture is performed one after another in the same manner. Therefore, by selecting the number of layers of the backup filtration layer F,
The cutting waste 4 can be filtered while being almost completely prevented from flowing out to the drainage side, and the common drawbacks of the methods shown in FIGS. 1a and 1b are eliminated. In addition, in the present invention, since the filter cylinder is formed by rolling up multiple layers of filter paper, the
As a result, the total area of the filter paper can be significantly increased compared to the above-mentioned cartridge type. Therefore, the time during which continuous filtration can be carried out can be significantly extended, and the time and labor required for replacing filter paper can be drastically reduced. For example, in a cartridge system, when a filter paper with a length of 5 m and a width of 0.5 m is rolled up so that the outer diameter is 0.5 m, the area of the filter paper is 2.5 m ² . On the other hand, in the present invention, if the same size filter paper is wound 1000 times with an average diameter of 0.3 m, the total area will be about 471 ^m2 , which is about 188 times as much as the cartridge method.
Furthermore, since the thickness of one sheet of filter paper is generally around 0.2 mm, even if it is rolled 1000 times, the thickness of the roll is 0.2 m. Therefore, even if this thickness is considered to be on top of the average diameter of 0.3 m, its outer diameter will be approximately the same as the outer diameter of the cartridge system, and it can be formed by being accommodated in a container with approximately the same diameter. Furthermore, in the filter paper rolled into a roll shown in FIG. 1b, which is rolled through a water passage section and filtered, the filter paper winding section, water passage section, and winding section are in series, Moreover, when wound up in the winding section, the outer diameter of the roll is the same as the outside diameter of the winding section at the beginning of filtration, and the same space is required. Therefore, the apparatus becomes large-sized, but in the present invention, the filter is wound up by a winding shaft within the filter cylinder, and the outer diameter of the filter cylinder is always constant, so there is an advantage that it can be made compact.

Next, specific examples of the present invention will be explained. FIGS. 4a and 4b are a partial longitudinal cross-sectional view showing an embodiment of the present invention and a cross-sectional view taken along the plane A-A',
In the figure, 10 is a closed container, 10a is an inlet for water to be treated, 10b is an outlet for purified water, and 10c is a lid for replacing the filter cylinder, which can be attached and detached using bolts and nuts. Reference numeral 5 denotes a filter cylinder, which is formed by winding a filter paper so as to form a cavity 5a in the center, and an adhesive layer 5b is provided on both upper and lower end surfaces of the cylinder to a thickness that does not impede winding of the filter paper. The filter body 5 is formed so that the water to be treated enters only from the inner peripheral surface side. Reference numeral 11 is a cylindrical punched metal plate having a large number of holes, and its upper and lower ends are welded and fixed to the inner wall surface of the closed container 10 in a watertight manner. 1
2 is an annular lower support plate whose outer peripheral portion is watertightly connected to the lower end of the punched metal plate 11, and 13 is an annular upper support plate which is detachably screwed to the punched metal plate 11 in a watertight manner. Then, after inserting the filter cylinder 5 with watertight gaskets 5c adhered to the outer peripheral surfaces of both upper and lower ends into the punched metal plate 11, the upper support plate 13 is screwed to the upside down part of the punched metal plate 11, and the filter cylinder 5 is By sandwiching them from above and below, the water to be treated can be transferred to the upper and lower support plates 12,
The filter cylinder 5 is supported so that clean water does not flow out from the gap between the filter cylinder 13 and the filter cylinder 5 through the punched metal plate 11 to the outlet side. Reference numeral 6 indicates a winding shaft, and 14 indicates an upper bearing disc which is fixed together with the lid 10c. 15 is a lower watertight bearing, and the winding shaft 6 is rotated by an electric motor 16 via a reduction gear 17. 8 is a pressure welding piece, 18,
Reference numeral 19 denotes upper and lower supports for the pressure contact piece, which are fixed above and below the winding shaft 6. As shown in FIG. 4b, the pressure contact piece 8 is movably supported by upper and lower supports 18 and 19 inserted into support holes 8a and 8b provided at its upper and lower ends, and is supported vertically by a spring body 7. Support 1
Radial long holes 12a and 13a provided in 2 and 13
As the filter paper is wound up, the inside moves in the outer circumferential direction and is always in pressure contact with the inner peripheral surface of the filter cylinder 5, regulating the winding position of the filter paper 1 so that the filter paper wound around the filter cylinder 5 does not loosen. Then, the water to be treated sent from the inlet 10a is filtered by passing from the inner peripheral surface side to the outer peripheral surface side of the filter cylinder 5 as shown by the arrow in the figure, and becomes clean through the punched metal plate 11 and the outlet 10b. The water is discharged from the outlet 10b. 20 is a pressure detector, 21 is an electronic switch, and the pressure detector 20 detects the pressure increase on the inflow side of the water to be treated of the filter barrel 5, and this detects, for example, A in the operation process diagram shown in FIG.
When the pressure reaches 2 to 3 kg/cm ² , a signal is sent out and the electronic switch 21 is turned on to drive the electric motor 16 and cause the winding shaft 6 to wind up the filter paper 1. When the accumulated part of the cutting waste 4 is wound up and the pressure returns to the original value as shown in FIG.
1. Repeat the above operation every time the pressure rises to remove a new filter paper 1.
is located on the inflow surface of the water to be treated. Reference numeral 22 denotes a winding regulation switch, such as a reed switch, whose lead wire passes through the closed container 10 in a watertight manner and is drawn out. Reference numeral 22a denotes an actuator thereof, and 23 denotes a signal generating circuit, which are provided at the lower end of the pressure contact piece 8.
When the thickness of the filter drum 5 reaches a certain level due to the winding of the filter paper 1 by the winding shaft 6, the electronic switch 21 is turned off to prevent further winding by the electric motor 16. A back-up filter paper layer F having a thickness that does not necessarily allow cutting waste 4 to flow out to the discharge side
leave. Therefore, if the filtration continues as it is, the cutting debris 4 will continue to accumulate on the inner circumferential surface of the filter cylinder 5.
24 is a timer, 25 is an electromagnetic switching valve, and 26 is another liquid filtration device according to the present invention. When the pressure at point C in FIG. 5, for example, a pressure of 2 to 3 kg/cm ² or more is continuously detected for a certain period of time, it operates and sends out an output.
Then, the electromagnetic switching valve 25 is switched to the liquid filtration device 26 side so that filtration continues. 2
7 is an inlet for wastewater from the cutting device, and experiments using this example device revealed that the filtered water to be treated has a high degree of cleanliness and can be continuously treated for a long time. .

For example, when waste water from a cutting device containing about 30,000 to 50,000 pieces of cutting waste per 10 c.c. is filtered at a flow rate of 25/min, the number of cutting pieces in the waste water is
There were 100 to 300 particles, and the particle size of the discharged particles was 0.3 μ to 1 μ. Furthermore, even after continuous operation for 500 hours, there was almost no change in filtration performance. Generally, each semiconductor cutting device requires 25/min of water (industrial water or pure water), and it is common for one factory to have 30 cutting devices and operate continuously for 24 hours.
Therefore, the amount of water per 30 days is 25 x 60 x 24 x per unit.
30 = 1080 tons, that is, 1080 x 30 tons per month, which is an extremely large amount, and the water bill will be large. However, since the filtration according to the invention is very efficient and no chemicals are used for the treatment, the waste water can be reused and water can be saved significantly.

Although the above description has been about wastewater from cutting equipment in semiconductor devices, it is of course applicable to other wastewater treatments such as wastewater treatment in nuclear power plants. All you have to do is determine the efficiency.
Furthermore, in the above embodiment, the back-up filtration layer F was always left on the discharge side and the back-up filtration layer F was wound up, but this back-up filtration layer F was made separately and fitted around the outer periphery of the filtration drum 5, so that the filter paper of the filtration drum 5 was finally It is also possible to wind it up to the maximum length.
According to this method, it is possible to omit a device such as the reed switch 22 for winding up the filtration layer F while leaving it behind, thereby simplifying the device.

In addition, in the above description, the filter body was formed by winding paper-like filter media, but threads such as fibers of 2 to 20 μm with an outer diameter of 3 to 8
As shown in the perspective view in Fig. 6, long threads made by bundling them to a length of
A and a thread 28b forming the next layer are wound to intersect with each other to form a filter cylinder 5, and this thread 28 is wound around a winding shaft 6.
It may also be configured to wind up cutting waste each time it accumulates. In this case, the voids between the threads, as well as the voids between the fibers forming the threads, perform a filtration action. Therefore, the method of winding the thread, the winding interval, the type of thread, etc. may be selected in order to obtain the required filtration efficiency.

As is clear from the above description, according to the present invention, it is possible to provide a compact liquid filtration device that can efficiently remove particles in a liquid continuously for a long period of time, and the practical effects are remarkable.

[Brief explanation of the drawing]

Figures 1a and b are schematic explanatory diagrams of the conventional device;
Figure 3 is an explanatory diagram of the principle of the present invention, Figure 4 a, b
5 is a partial longitudinal cross-sectional view showing one embodiment of the present invention and a cross-sectional view taken along the line A-A', FIG. 5 is an operation process diagram, and FIG. FIG. 1...filter paper, 2...case, 3...take-up roll, 4
... Cutting waste, 5... Filter cylinder, 5a... Adhesive layer, 5c...
Watertight packing, 5a...cavity part, 6...take-up shaft, F...
Backup filtration layer, 7... Spring body, 8... Pressure contact piece, 8a, 8
b...Support hole, 9...Spring body, 10...Airtight container, 10
a... Inlet of treated water, 10b... Outlet of clean water, 1
0c...Lid, 11...Cylindrical punching metal plate, 1
2, 13...Annular upper and lower support plates, 12a,
13a... Elongated hole for moving the pressure welding piece, 14... Upper bearing plate,
DESCRIPTION OF SYMBOLS 15...Lower watertight bearing, 16...Electric motor, 17...Reducer, 18, 19...Upper and lower supports of the pressure contact piece, 20...Pressure detector, 21...Electronic switch, 22...Rewinding regulation switch, 22a...It actuator, 23... Control signal generation circuit, 24... Timer, 25... Solenoid switching valve, 26... Another liquid filtration device according to the present invention, 27... Water source to be treated, 28... Thread, 28a, 28
b...The going thread and the returning thread.

Claims (1)

[Claims] 1. From a filter cylinder formed by winding a filter medium so as to have a hollow part in the center, the filter medium is wound up by a winding shaft provided in the hollow part so as to leave a backup filtration layer on the outer periphery of the filter cylinder. 1. A liquid filtration device characterized in that the water to be treated is supplied from the inner circumferential surface of a filtration drum and filtered.