JP2577014B2 - Pure water supply device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention relates to a normal water supply device including at least a reverse osmosis membrane device and a regenerative pure water device, and is obtained from the pure water supply device. The present invention relates to a pure water supply apparatus capable of continuously supplying pure water during regeneration of the regeneration type pure water apparatus without particularly providing a tank for storing pure water.

<Prior art> In the electronics industry that manufactures LSIs and VLSIs, when cleaning semiconductor wafers or chips (semiconductor wafers), which are intermediate products, in order to improve the yield, the amount of ions and fine particles must be reduced. It requires so-called ultrapure water which not only reduces the amount to the order of ppb but also reduces the number of viable bacteria to 10 ^-1 cells / ml.

Such ultrapure water is usually produced according to the flow shown in FIG.

That is, first, the raw water is treated with a pretreatment device such as a coagulation sedimentation device, a sand filter, and an activated carbon filter to obtain clear raw water,
The raw water 1 is supplied to a reverse osmosis membrane device 3 by a raw water pump 2. The supplied raw water 1 is separated by a reverse osmosis membrane into permeated water and concentrated water, and the permeated water is guided to a permeated water storage tank 5 by a permeated water pipe 4, while the concentrated water is discharged out of the system from a concentrated water pipe 6. The permeated water guided to the permeated water storage tank 5 is further supplied to a latter-stage regenerated deionized water device 8 using an ion exchange resin by a permeated water pump 7 and is provided with pure water having the highest possible purity (hereinafter referred to as primary pure water). ) To manufacture. The above is the pure water supply device, and in the case of an ultrapure water production facility, this is generally called a primary water supply device. The obtained primary pure water is temporarily stored in the primary pure water storage tank 9.

As the regeneration type pure water device 8 used in the pure water supply device, a mixed-bed type pure water device having a regeneration facility in the device,
A floor three-tower type pure water apparatus, an apparatus combining these, and the like are exemplified.

Next, a primary pure water in the primary pure water storage tank 9 is combined with a primary pure water pump 10 by using a combination of, for example, an ultraviolet irradiation device, a mixed-bed pure water device, an ultrafiltration membrane device, and the like.
11 (in FIG. 2, they are collectively indicated by dotted lines)
To obtain a so-called ultrapure water which is further purified than the primary pure water. The ultrapure water is further used at the point of use
The wafer is transferred to a use point 13 surrounded by a dashed line by 12, where most of the water is used as cleaning water for semiconductor wafers, and the remaining ultrapure water is circulated to the primary pure water storage tank 9.
If the ultrapure water is not used temporarily at the use point 13, the operation is continued without stopping the primary pure water pump 10 and the subsystem 11, and the entire amount of the obtained ultrapure water is transferred to the use point piping. Primary pure water storage tank 9 via 12A
So that it circulates. Because subsystem 11
If the operation was stopped and water remained in the subsystem 11 system, then when the operation was started again,
This is because the number of bacteria, fine particles and the like increases in the obtained ultrapure water, which causes a serious problem that the water quality of the ultrapure water deteriorates.

Meanwhile, in the pure water supply device shown in FIG. 2, about 90% of the impurity ions contained in the raw water are removed by the reverse osmosis membrane device 3, and the remaining impurities that cannot be removed by the reverse osmosis membrane device 3 are removed. Approximately 10% of impurity ions are removed by ion exchange in a regeneration type pure water apparatus 8 installed at the subsequent stage. The removal of the residual impurity ions by the pure water device 8 is continued to reach the specified water flow rate, or the capacity of the ion exchange resin filled in the pure water device 8 is reduced, and the primary purity of the target purity is reduced. If pure water can no longer be obtained, the flow of permeated water to the pure water device 8 is interrupted, and then the attached regeneration equipment (not shown) is used to regenerate the ion exchange resin as usual. I do. As described above, since the amount of impurity ions contained in the permeated water passing through the pure water device 8 is as small as about 10% of that in the raw material, the ion load on the pure water device 8 is relatively small. Therefore, its reproduction frequency is usually 2
Once every 5 days.

Regeneration usually requires 2 to 4 hours, but in the pure water supply apparatus shown in FIG. 2 having only one regeneration type pure water apparatus, production of primary pure water is naturally stopped during this time. You. However, even during this time, the production itself of ultrapure water cannot be stopped. Therefore, in the ultrapure water production apparatus of the flow shown in FIG. 2, while the regeneration type pure water apparatus 8 is being regenerated, the supply of the primary pure water to the subsystem 11 is continued, and the ultrapure water is continuously supplied. In order to be able to manufacture the primary pure water, a necessary amount of primary pure water was previously stored in the primary pure water storage tank 9 during this time.

As another example of the ultrapure water producing apparatus capable of continuously supplying the ultrapure water even at the time of regeneration of the regeneration type pure water apparatus, as shown in FIG. There is an apparatus provided with two regenerative pure water apparatuses 8 (8A, 8B) in parallel in the system. In this system, the second-stage regenerative pure water system 8
It is intended to continuously supply primary purified water to the subsystem 11 by alternately using A and 8B, and thus to continuously produce ultrapure water, and other parts are shown in FIG. It is almost the same as the one.

The production of primary pure water in the pure water supply device shown in FIG. 3 is performed as follows.

That is, the permeated water is passed through the permeated water pump 7A to one of the regenerated pure water devices that have already been regenerated, for example, the regenerated pure water device 8A, to produce primary pure water. On the other hand, the regeneration type pure water apparatus 8B to be regenerated after the water supply has already been terminated is regenerated using the attached regeneration equipment during this time.
Make sure that water is available at all times.

The flow of the permeated water to the regeneration type pure water device 8A is continued, for example, when the flow amount reaches a specified amount, the flow path of the permeated water is switched, and the permeated water is then passed through the permeated water pump 7B. In this case, the primary pure water is produced by passing water through the regenerative pure water apparatus 8B that has been kept on standby, while the regenerative pure water apparatus 8A regenerates in accordance with a conventional method. Wait until the water season.

<Problems to be Solved by the Invention> However, the above-described conventional pure water supply device has the following problems.

In other words, in a pure water supply apparatus as shown in FIG. 2 in which only one regeneration type pure water apparatus is provided, as described above, the supply to the downstream subsystem is performed during the regeneration of the pure water apparatus. Since the amount of primary pure water to be stored must be stored in the primary pure water storage tank in advance, a relatively large-capacity primary pure water storage tank is required. There is a problem that a building for accommodating equipment including the above must be enlarged.

In addition, in a pure water supply apparatus as shown in FIG. 3 in which two regenerative pure water apparatuses are provided and used alternately, one relatively large and expensive regenerative pure water apparatus is added. At the same time,
Also in this case, as shown in FIG. 3, the equipment of the primary pure water storage tank is indispensable, and there is also a problem that a large installation area and a large building are required. The reason is as follows. That is, in the pure water supply apparatus, the regeneration type pure water apparatus which has already completed the regeneration and has been put on standby in a state in which water can be passed from one regeneration type pure water apparatus which has been supplying water so far. When the water flow is switched, the primary pure water of the required purity is not always obtained immediately after the water flow, but the primary pure water of the required purity is usually obtained within 10 to 30 minutes after the start of water flow. Can not be obtained. This is because, in a regeneration type pure water apparatus using an ion-exchange resin, there is generally no problem when water is started immediately after regeneration, but it is not so. If
During this time, a very small amount of ions remaining in the ion-exchange resin used in the pure water apparatus and originating from the regenerating chemicals such as hydrochloric acid and caustic soda used at the time of the regeneration are discharged outside the ion-exchange resin particles. Will gradually leak out,
Eventually, this leaks into the primary purified water, which is the treated water, at the initial stage of water flow after the standby, and causes the above-described purity reduction.

Since it is not preferable to supply the treated water having the reduced purity to the subsystem at the subsequent stage, the purity obtained at the beginning of the passage of the permeated water to the regeneration-type pure water apparatus which was conventionally kept on standby is obtained. Low treated water is returned to the permeated water storage tank at the previous stage without being introduced into the primary pure water storage tank, and the so-called circulating washing is performed for 10 to 30 minutes, and the treated water purity of the regeneration type pure water equipment is regulated. Water collection as primary pure water was started only when the purity was reached. Therefore, while performing the circulation cleaning, the production of the primary pure water is stopped.If the primary pure water storage tank is not provided, the production of the ultrapure water itself is also stopped during this period. Is clear.

The above is the reason why the equipment for the primary pure water storage tank is indispensable even in the pure water supply device as shown in FIG. In addition,
In this case, the capacity of the primary pure water storage tank may be smaller than that of the pure water supply apparatus shown in FIG. 2 having only one regenerative pure water apparatus. Since it is necessary to provide an extra mold pure water device,
As a whole, the pure water supply apparatus becomes large.

As described above, in the conventional pure water supply apparatus, in order to always supply pure water of a specified purity continuously, it is essential to install a pure water storage tank having a somewhat large capacity.

The present invention has been made in view of the above-described problems in the conventional pure water supply device, and it is possible to continuously supply pure water without particularly installing the pure water storage tank, which was conventionally indispensable. It is an object of the present invention to provide a pure water supply device that can be made, and therefore, the installation area can be made smaller than before, and the equipment is inexpensive.

<Means for Solving the Problems> The present invention has the following configuration to achieve the above object.

That is, a reverse osmosis membrane device for performing reverse osmosis membrane treatment of raw water that has passed through a pretreatment device such as a coagulation sedimentation device and a sand filter, and a regeneration facility for performing deionization treatment on permeated water of the reverse osmosis membrane device. A regenerating pure water apparatus having at least a non-regenerating pure water apparatus having no regenerating equipment connected to the subsequent stage of the regenerating pure water apparatus, and a permeated water of the reverse osmosis membrane apparatus. A recirculating pure water apparatus and a non-regenerative pure water apparatus in order to allow water to pass in order, and a bypass that allows the permeated water to flow directly to the non-regenerative pure water apparatus without passing through the regenerative pure water apparatus. A pipe is provided, and in a steady state, the permeated water is passed through a regeneration type pure water apparatus and a non-regeneration type pure water apparatus in order to produce pure water. Ultrapure water can be produced by passing water through a regenerative water purifier. That.

 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram of a flow showing an example in which the pure water supply device of the present invention is applied to ultrapure water production.
Reverse osmosis membrane device for treating the raw water 1 supplied by the reverse osmosis membrane, 5 is a permeated water storage tank for storing permeated water of the reverse osmosis membrane device 3, and 8 is a permeated water storage tank supplied by a permeate pump 7. 5 is a regeneration type pure water apparatus for deionizing the permeated water in 5, and the flow up to here is the same as that of the conventional apparatus. The feature of the present invention is that the regeneration-type pure water device 8
By connecting a non-regenerative pure water device 14 having no regeneration equipment, permeated water in the permeated water storage tank 5 can be passed through the permeated water pump 7, the regenerative pure water device 8, and the non-regenerative pure water device 14 in this order. In addition, a bypass pipe 15 is provided to allow the permeated water in the permeated water storage tank 5 to flow directly to the non-regenerative pure water device 14 without passing through the regeneration type water purifier 8. As shown in FIG. 1, the bypass pipe 15 has one end connected to the permeated water storage tank 5 and the other end branched to a pipe 16 connecting the regeneration type pure water apparatus 8 and the non-regenerative type pure water apparatus 14. It is provided. In the middle of the bypass pipe 15, a preliminary pump 17 for supplying the permeated water in the permeated water storage tank 5 to the non-regenerating pure water apparatus 14 is provided. The method of attaching the bypass pipe 15 is not limited to the above-described example. For example, one end of the bypass pipe 15 is branched and connected to the pipe 18 on the discharge side of the permeated water pump, and the other end is branched and connected to the pipe 16 in the same manner as described above. In this case, the preliminary pump 17 can be omitted.

The non-regenerative pure water apparatus 14 used in the present invention is a so-called cartridge type pure water in which a column is filled with a mixed resin of a strong acidic cation exchange resin and a strong basic anion exchange resin which has been regenerated elsewhere in advance. It is called an apparatus and does not have a regeneration facility in the apparatus. Therefore, when the processing capacity of the non-regenerating type pure water apparatus 14 is reduced, the charged ion exchange resin is not regenerated and replaced with another ion exchange resin regenerated in another place before use. Type.

11 is a subsystem, and 12 is a subsystem 11
This is a use point pipe for transferring ultrapure water obtained from the above to a use point 13 surrounded by a dashed line. However, in FIG. 1, unlike the conventional case, the use point piping 12 is provided so that part or all of the ultrapure water transferred by the use point piping 12 is circulated to the permeated water storage tank 5.

<Operation> The operation of the apparatus of the present invention will be described with reference to FIG.

In a steady state in which the regeneration type pure water apparatus 8 is in a regenerated and water-permeable state, the production of pure water and the production of ultrapure water are performed as follows.

That is, raw water 1 purified through a pretreatment device (neither is shown) such as a coagulation sedimentation device and a sand filter is subjected to reverse osmosis membrane treatment in a reverse osmosis membrane device 3, and the resulting permeate is stored in a permeate storage tank. 5 is the same as before.

The permeated water guided to the permeated water storage tank 5 is passed through a permeated water pump 7 and a pipe 18 to a regenerative pure water apparatus 8 to remove impurity ions contained in the permeated water, and is converted into conventional primary pure water. Corresponding, highly pure treated water is obtained. In the present invention, the treated water is further passed through a non-regenerative pure water apparatus 14 at the subsequent stage via a pipe 16 to obtain pure water with higher purity. Since the treated water of the regeneration-type pure water apparatus 8 contains almost no impurity ions, even if the treated water is further passed through the non-regeneration-type pure water apparatus 14, The capacity of the ion exchange resin in the inside hardly decreases.

The pure water obtained from the non-regenerative pure water apparatus 14 is supplied directly to the subsystem 11 for processing without passing through a primary pure water storage tank as in the prior art, and so-called ultrapure water is obtained. The obtained ultrapure water is transported to a use point 13 surrounded by a dashed line by use point piping 12, where most of the ultrapure water is used as cleaning water for semiconductor wafers, and the remaining ultrapure water is used at the use point. Permeated water storage tank 5 at the previous stage via pipe 12A
Circulates. Also, even when the ultrapure water is not used at the use point 13 at all, the production of the ultrapure water is continued without stopping the production of the ultrapure water itself, and the entire amount of the obtained ultrapure water is circulated to the permeated water storage tank 5. I do.

Continue the pure water production in the steady state as described above,
If the flow rate of the permeated water to the regeneration type pure water device 8 reaches the specified amount, or if the capacity of the ion exchange resin filled in the pure water device 8 is reduced, the permeated water pump 7
Is stopped, and the flow of water to the regeneration-type pure water apparatus 8 is stopped. At the same time, operate the necessary valves (not shown) and
By driving 17, the flow path of the permeated water is switched to the bypass pipe 15 side, and the permeated water is passed directly to the non-regenerative pure water device 14 via the bypass pipe 15 and the pipe 16. Therefore, at this time, the deionized water is deionized by the non-regenerating pure water apparatus 14 to obtain pure water having the same quality as that of the conventional primary pure water, and the pure water is supplied to the sub-system 11 at the subsequent stage to be ultra-pure. Continue production of pure water. Subsequent operations are the same as those in the above-described steady state.

In the present invention, even during the above-described steady-state pure water production, the non-regenerative pure water device 14 is not simply kept on standby, and the treated water of the regenerative pure water device 8 is constantly treated with the non-regenerative pure water. Since the water is passed through the device 14, the regeneration type pure water device 8
To the non-regenerative pure water system 14
In the case of switching to, pure water having a purity equivalent to conventional primary pure water can be obtained immediately from the beginning. Therefore, unlike the case of the conventional pure water supply apparatus in which two regenerative pure water apparatuses are used alternately, the pure water is continuously supplied without particularly providing the pure water storage tank which is conventionally indispensable in the present invention. In addition, the pure water supply pump (the primary pure water pump 10 in FIG. 2 or 3) attached to the tank can be omitted.

While the permeated water is directly passed through the non-regenerative pure water apparatus 14, the regeneration of the regenerative pure water apparatus 8 is performed by using the attached regeneration equipment (not shown) during the above pure water production. Do. After the regeneration, the flow path of the permeated water is switched again, and the permeated water is passed through the regeneration type pure water apparatus 8 and the non-regeneration type pure water apparatus 14 in this order, and the above-described steady-state pure water production is performed.

As is apparent from the above description, the ion load on the non-regenerative pure water apparatus 14 used in the present invention is almost negligible during the steady-state pure water production, and most of the ion load is on the regenerative pure water apparatus 8. This is derived from a relatively small amount of permeated water that passes within a short time (usually 2 to 4 hours) during the regeneration. Therefore, the ion load on the non-regenerative pure water device 14 is significantly less than the ion load on the regenerative pure water device 8 that continues permeating water for about 2 to 5 days.
Therefore, the scale of the non-regenerative pure water apparatus 14 is
Can be considerably smaller than. Incidentally, when the flow rate of the permeated water to the non-regenerative pure water device 14 reaches the specified amount, or when the capacity of the ion exchange resin used in the non-regenerative pure water device 14 is reduced, Instead of regenerating the ion-exchange resin, the ion-exchange resin is replaced with another ion-exchange resin regenerated in another place in advance, and the production of ultrapure water is continued. The exchange of the ion exchange resin may be usually performed every 2 to 6 months.

In the above-described embodiment, an example in which the pure water supply device of the present invention is applied to the field of ultrapure water production has been described, but the present invention is not limited to this, and any field that requires pure water is applicable. It can also be applied to fields.

<Effects> As described above, according to the present invention, a pure water storage tank such as a primary pure water storage tank and an associated pure water supply pump which are indispensable in the conventional apparatus are not required, and a regeneration facility is provided. There is no need to install two expensive regenerative water purifiers, and pure water can be continuously supplied only by installing a very inexpensive non-regenerative water purifier that is smaller and has no regeneration equipment. Since it can be manufactured and supplied, it is very economical and space-saving, and its usefulness is extremely large.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of a flow showing an example in which the pure water supply apparatus of the present invention is applied to ultrapure water production, and FIGS. 2 and 3 each show a conventional pure water supply apparatus. It is explanatory drawing which shows the flow of the ultrapure water production apparatus using a water supply apparatus. 1 ... raw water 2 ... raw water pump 3 ... reverse osmosis membrane device 4 ... permeated water pipe 5 ... permeated water storage tank 6 ... concentrated water pipe 7 ... permeated water pump 8 ... regenerated pure water equipment 9… Primary pure water storage tank, 10… Primary pure water pump 11 …… Subsystem 12 …… Use point piping 13 …… Use point 14 …… Non-regenerative pure water equipment 15 …… Bypass piping 16 and 18 …… Piping 17 …… Preliminary pump

Claims (1)

(57) [Claims] 1. A reverse osmosis membrane device for subjecting raw water that has passed through a pretreatment device such as a coagulation sedimentation device or a sand filter to a reverse osmosis membrane treatment, and a deionization treatment for permeated water of the reverse osmosis membrane device. A regenerative pure water apparatus having at least a regenerating pure water apparatus having a regenerating facility, wherein a non-regenerating pure water apparatus having no regenerative facility is connected to a stage subsequent to the regenerative pure water apparatus, The permeated water can be passed through the regeneration type pure water device and the non-regenerative type pure water device in this order, and the permeated water can be passed directly to the non-regeneration type pure water device without passing through the regeneration type pure water device. Such a bypass pipe is provided, and in a steady state, the permeated water is passed through a regenerative pure water apparatus and a non-regenerative pure water apparatus in this order to produce pure water. Directly through a non-regenerative pure water system to produce pure water. Pure water supply apparatus according to symptoms.