JP2000033250A - Method and apparatus for producing salts-containing water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable adjustment to a low concentration in which only the concentration of salts is aimed while the balance of desirable ionic components is being kept by providing a means which mixes filtrate from a filtrate producing apparatus with pure water from a pure water producing apparatus and prepares salts-containing water of an aimed concentration. SOLUTION: Filtrate from a filtrate storage tank 14 is mixed with pure water from a pure water storage tank 16 in a prescribed ratio in a salts- containing water preparation tank 17 comprising a batch-type mixing tank, and salts-containing water of a prescribed salts concentration is prepared. The signal of the conductivity of the pure water stored in the tank 17 and the signal of the conductivity of the filtrate measured by a conductivity meter 25 are sent to an operation/control device 26, and the amount of the filtrate to be mixed in order to adjust the concentration to an aimed salts concentration is operated from the values of conductivity and the amount of pure water in the tank 17 which is grasped in advance. The operation of a pump 23 is controlled in order to supply an operated amount of the filtrate while a detected signal from a flow meter 27 is being inputted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for producing salt-containing water having a salt concentration lower than that of ordinary filtered water, and particularly to an apparatus for producing salt-containing water capable of automatically preparing a target concentration of salt-containing water. And a manufacturing method.

[0002]

2. Description of the Related Art In the field of producing various beverages such as carbonated beverages, coffee, tea, and juices, filtered water, for example, city water, is filtered as a water for producing beverages using a membrane filtration device or an activated carbon filter. Water or pure water produced by a pure water producing apparatus is often used. In the filtered water, although impurities such as suspended substances are removed by filtration, salts (for example, sodium ions, calcium ions, magnesium ions, etc. as cation components, chloride ions and sulfides as anion components, etc.) Ion etc.) concentration is almost the same as raw water before filtration.
Usually, salts are removed by a desalting means such as an ion exchanger or a reverse osmosis membrane, so that the salt concentration is extremely low.

However, recently, depending on the beverage to be produced, the salt concentration of raw water is kept low while maintaining the balance of the ions contained in the raw water substantially (that is, the salt concentration is lower than that of filtered water but lower than that of pure water). It has been found that water with a low salt content has a subtly desirable effect on the taste and flavor of the beverages produced, and testing on a beaker scale has begun. In tests at the beaker scale, various low-salt content waters can be prepared by changing the ratio of filtered water and pure water and mixing both, but satisfying such requirements on an industrial scale There is no device that can do this.

[0004]

SUMMARY OF THE INVENTION The present invention has been completed as a result of intensive studies to meet the recent new demands as described above.

That is, the production of low-salt content water in which pure water is simply mixed with filtered water is time-consuming,
The production volume is limited, and it is difficult to use it on an industrial scale. In addition, it is difficult to automatically prepare salt-containing water having a target concentration.

It is also conceivable to add salts such as NaCl to pure water produced by a pure water producing apparatus to produce salt-containing water at a desired concentration. However, once the salts are removed by a pure water producing apparatus, the salt is removed. In addition to the waste in the system of adding water, there is a possibility that the ion balance of the raw water may be lost and the desired ion balance as drinking water may not be achieved. That is, it is not possible to meet the demand for lowering only the salt concentration while leaving the raw water component substantially as it is.

[0007] Accordingly, an object of the present invention is to meet the above-mentioned new requirements for low-salt content water, while maintaining a desirable balance of ionic components in the raw water and adjusting the salt content to a target low concentration only for the salt concentration. An object of the present invention is to provide an apparatus and a method for producing water.

Another object of the present invention is to provide an apparatus and a method for producing salt-containing water that can easily and automatically prepare desired low salt-containing water.

[0009]

In order to solve the above-mentioned problems, an apparatus for producing salt-containing water according to the present invention mixes filtered water from a filtered water producing apparatus and pure water from a pure water producing apparatus. It is characterized by having means for preparing salt-containing water at a target concentration.

Here, the filtered water and the pure water may be produced from the same raw water or different raw waters. When producing from the same raw water, for example, a system using filtered water may be used as raw water for producing pure water.

The filtration water producing apparatus is not particularly limited. For example, a sand filtration apparatus or an activated carbon filtration apparatus, or a microfiltration membrane (MF) or an ultrafiltration membrane (U
Examples of the pure water production apparatus include a known pure water production apparatus using a desalting unit such as an ion exchange resin or a reverse osmosis membrane. Can be mentioned.

Preferably, the means for preparing salt-containing water is provided with means capable of substantially detecting the concentration of salts in the mixed water of filtered water and pure water, and information from the detecting means is provided. It is preferable that feedback is provided to at least one of the filtered water supply system and the pure water supply system. Further, it is preferable that the filtrate water supply system is also provided with means capable of substantially detecting the concentration of salts of the filtrate water at the same time. By feeding back information from such a detecting means, it becomes possible to easily automate the preparation of the mixed water having the target salt concentration.

Although it is difficult to measure the salt concentration directly because it contains various ions, it is known that the salt concentration and the electric conductivity correspond substantially one to one in a certain concentration range. Therefore, an electric conductivity detecting means can be used as the means for detecting the salt concentration substantially.

The means for preparing the salt-containing water can be constituted by either a batch system or a continuous system. In the case of a batch type, a batch type mixing tank of filtered water and pure water may be provided.In the case of a continuous type, a continuous mixing system of filtered water and pure water may be formed as a line configuration. Good.

Such an apparatus for producing salt-containing water is suitable for use in industrial production of salt-containing water having a target concentration, particularly as drinking water.

In the method for producing salt-containing water according to the present invention, filtered water is produced by a filtered water producing device, pure water is produced by a pure water producing device, and the filtered water and pure water are mixed at a predetermined ratio. The method comprises preparing salt-containing water having a target salt concentration intermediate between the salt concentration of filtered water and the salt concentration of pure water.

In the apparatus and method for producing salt-containing water according to the present invention, since filtered water and pure water are mixed to produce salt-containing water having a desired salt concentration, the source of the filtered water is particularly high. The component balance and ion balance of the raw water are utilized substantially as it is, and in the mixed water, substantially only the salt concentration is reduced to the target concentration. Therefore, the desired concentration of salt-containing water can be easily produced while the desired ion balance required for beverages and the like is left.

Further, by detecting electric conductivity or the like, mixed water,
Furthermore, if the salt concentration of the filtered water to be mixed is detected and the mixing ratio between the filtered water and the pure water can be controlled, the salt-containing water at the target concentration is automatically reduced and the variation in the concentration is reduced. It can be prepared with high precision and can be easily used industrially.

[0019]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a basic configuration of an apparatus and a method for producing salt-containing water according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an entire apparatus for producing salt-containing water.
The filtered water is temporarily stored in the filtered water storage tank 3. Further, a part of the filtered water is supplied to the pure water producing device 4, where pure water is produced and temporarily stored in the pure water storage tank 5. The pure water production device 4 includes:
For example, a mixed bed type pure water production apparatus using a cation exchange resin and an anion exchange resin is used. As the raw water of the pure water production apparatus 4, in addition to using the filtered water as described above, city water or the like may be directly used.

The filtered water from the filtered water storage tank 3 and the pure water storage tank 5
Is mixed at a predetermined ratio by the salt-containing water preparing means 6 to prepare low salt-containing water in which the salt concentration is adjusted to the target concentration.

For controlling the salt concentration, for example, detection of electric conductivity (also referred to as electric conductivity) can be used. That is, it is known that there is a proportional relationship between the concentration of salts dissolved in water and the electric conductivity within a certain concentration range. Therefore, if the target value of the salt concentration of the salt-containing water to be prepared, that is, the target value of the electric conductivity is set, the electric conductivity of the filtered water used for the preparation and the electric conductivity of the pure water are used. Can be calculated in what ratio should be mixed. For example, the electrical conductivity of the filtered water is 240μ
If S / cm and that of pure water are 1 μS / cm, when they are mixed in equal amounts, (240 + 1) / 2 ≒ 120 μ
S / cm of water is obtained, and low salt-containing water having a salt concentration about half that of the filtered water is obtained. In the present invention, the detection of the electric conductivity and the feedback control based on the detected value can be utilized very effectively when preparing the salt-containing water.

FIG. 2 shows a more specific embodiment in which salt-containing water is prepared in a batch system. In the apparatus for producing salt-containing water shown in FIG.
Filtration is performed by a filtration water production device 13 including a membrane filtration device 11 and an activated carbon filter 12 to generate filtered water. The generated filtered water is temporarily stored in the filtered water storage tank 14.
In addition, a part of the generated filtered water is sent to a mixed-bed type pure water producing apparatus 15 or the like, and pure water is generated by an ion exchange treatment. The generated pure water is temporarily stored in the pure water storage tank 16.

The filtered water from the filtered water storage tank 14 and the pure water from the pure water storage tank 16 are mixed at a predetermined ratio in a salt-containing water preparation tank 17 composed of a batch type mixing tank to prepare salt-containing water having a predetermined salt concentration. Is done. Various methods can be used for controlling the density adjustment at this time, examples of which are described below.

In this embodiment, first, a predetermined fixed amount of pure water is supplied from the pure water storage tank 16 to the salt-containing water preparation tank 1.
7 is supplied. At this time, the supply amount of pure water is
, And a predetermined fixed amount of pure water is supplied accurately.
Reference numeral 19 denotes an air filter attached to the salt-containing water preparation tank.

Next, the water in the preparation tank 17 is circulated through the circulation lines 21 and 29 by driving the attached pump 20, and before the pure water is supplied, the water in the preparation tank 17 and the circulation line 21 are circulated.
And the newly prepared water remaining in the pipe 29 and the newly supplied pure water are mixed well, and the electric conductivity of the mixed water is measured by the electric conductivity meter 22 (C) provided in the circulation line 21.
I).

On the other hand, the filtered water in the filtered water storage tank 14 is circulated through a circulation line 24 by a pump 23, and the electric conductivity of the filtered water is detected by an electric conductivity meter 25 (CI) attached to the circulation line. Measured. This filtered water is
A predetermined amount is supplied to the salt-containing water preparation tank 17 by the pump 23, and the supply amount is controlled as follows using the arithmetic and control unit 26.

The signal of the electric conductivity of the pure water stored in the preparation tank 17 measured by the electric conductivity meter 22 and the signal of the electric conductivity of the filtered water measured by the electric conductivity meter 25 are calculated. A target salt concentration based on the electric conductivity sent to the controller 26 and the amount of pure water in the salt-containing water preparation tank 17 (including the amount of water present in the circulation lines 21 and 29), which is grasped in advance; In order to adjust the amount of filtered water, the amount of filtered water to be mixed is calculated. The drive of the pump 23 is controlled while the detection signal from the (integrated) flow meter 27 is input so that the calculated amount of filtered water is supplied.

As a result, filtered water and pure water are accurately mixed at a predetermined ratio so that the prepared salt-containing water has the target electric conductivity. As described above, since the electrical conductivity and the salt concentration are in a proportional relationship, the salt-containing water having the target salt concentration is accurately prepared.

The prepared salt-containing water may be used, if necessary,
It is supplied to the point of use by the pump 20. In this embodiment, an ultraviolet sterilizer 2 is installed in this salt-containing water supply system.
8 are provided, but such attached devices may be provided as required. Further, in this embodiment, the circulation line 29 is circulated so as to always circulate in small amounts to prevent the growth of bacteria.
Is provided.

In the above-described apparatus and method for producing salt-containing water, since filtered water and pure water are mixed to prepare low salt-containing water having a target salt concentration, the original raw water contained in the filtered water is removed. Is substantially left as it is, and water having an ion balance desirable for beverages and the like is produced.

Therefore, as compared with a case where pure water is used and salts are added to the pure water to prepare salt-containing water having a desired salt concentration, the ion balance of the raw water or the filtered water can be substantially left as it is. It is possible to easily prepare salt-containing water which is desirable for drinking and the like. Further, when producing salt-containing water from pure water alone, there is a waste in the system of removing the salt once and then adding the salt again. In the present invention, there is no such waste, and the salt-containing water is not present. Manufacturing costs can also be reduced.

Further, by utilizing the detection of electric conductivity for adjusting the concentration of salts, even when various salts are contained, it is possible to control based on one index of electric conductivity. , And accurate density control can be easily performed. Furthermore, by calculating and controlling the mixing ratio of the filtered water and the pure water using the calculation / control device 26, automation can be easily achieved, and the concentration control can be further improved.

By the way, using the apparatus shown in FIG. 2, a test was conducted to confirm the accuracy of the concentration control by mixing and preparation based on the above-mentioned electric conductivity, and the following excellent results were obtained. .

The city water is passed through the membrane filtration device 11 and the activated carbon filter 1
2 and filtered water containing a large amount of salts (electric conductivity: 200 to 300 μS / cm), and the filtered water passed through a pure water production device 15 to obtain salts. Pure water (electric conductivity: about 1 μS / cm) containing almost no water is stored, and in the salt-containing water preparation tank 17, the electric conductivity becomes each target value (20 μS / cm and 2 μS / cm). As a result of preparing low-salt content water by mixing at a predetermined ratio, as shown in Table 1, it was possible to adjust the target salt concentration extremely accurately.

[0035]

[Table 1]

In the above embodiment, the case where the salt-containing water is prepared in a batch manner has been described. However, in the present invention, the salt-containing water can be prepared in a continuous manner.

For example, as shown in FIG. 3 showing the main part of the apparatus for producing salt-containing water, the electric conductivity of the filtered water is detected by the electric conductivity meter 33 in the circulation line 32 of the filtered water storage tank 31 as in the above embodiment. The filtered water is supplied by a pump 35 while controlling the flow rate of the filtered water by a flow control valve 34, and the filtered water is supplied to a pure water storage tank 3.
6 and pure water supplied by a pump 38 while controlling the flow rate by a flow control valve 37, are directly mixed in a mixing line 39, and the salt concentration of the mixed low salt content water is measured by an electric conductivity meter 40.
To detect. The calculating and controlling device 41 calculates the mixing ratio of the filtered water and the pure water using the measured value from the electric conductivity meter 33 so that the salt concentration measured by the electric conductivity meter 40 becomes the target value.
And the flow control valve 34 or both flow control valves 34 and 37 are controlled based on the calculation.

Even with such a continuous mixing / preparing system, salt-containing water having a desired salt concentration is produced with high precision, and is produced automatically and continuously.

Since the electric conductivity on the pure water side is usually a very low value, a sufficiently high concentration control can be performed only by measuring the electric conductivity after preparing the salt-containing water as shown in FIG. However, in order to further increase the control accuracy, the electric conductivity of pure water before mixing may be measured, and the information may be fed back.

[0040]

As described above, according to the apparatus and method for producing salt-containing water of the present invention, salt-containing water having a desired salt concentration can be produced easily and in large quantities, and can be used for beverages. Low salt content water which can meet new requirements can be efficiently and inexpensively produced on an industrial scale.

Further, by performing control based on the detection of electric conductivity, the production of desired salt-containing water can be easily automated.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a basic configuration example of an apparatus for producing salt-containing water of the present invention.

FIG. 2 is a schematic system diagram of an apparatus for producing salt-containing water according to an embodiment of the present invention.

FIG. 3 is a schematic system diagram of a main part of an apparatus for producing salt-containing water according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Production apparatus of salt-containing water 2,13 Filtration water production apparatus 3,14,31 Filtration water storage tank 4,15 Pure water production apparatus 5,16,36 Pure water storage tank 6 Salt-containing water preparation means 11 Membrane filtration apparatus 12 Activated carbon filter 17 Salt-containing water preparation tank 18 Liquid level gauge 19 Air filter 20, 23, 35, 38 Pump 21, 24, 29, 32 Circulation line 22, 25, 33, 40 Electric conductivity meter 26, 41 Operation / control device 27 ( Integration) flow meter 28 UV sterilizer 34, 37 flow control valve 39 mixing line

Claims (9)

[Claims] An apparatus for producing salt-containing water, comprising means for mixing filtered water from a filtered water producing apparatus with pure water from a pure water producing apparatus to prepare salt-containing water having a target concentration. . 2. The apparatus for producing salt-containing water according to claim 1, wherein said filtered water and pure water are produced from the same raw water. 3. The means for preparing salt-containing water is provided with means capable of substantially detecting the concentration of salts in a mixed water of filtered water and pure water, and the information from the detecting means is used to supply filtered water. The apparatus for producing salt-containing water according to claim 1 or 2, wherein the apparatus is fed back to at least one of the system and the pure water supply system. 4. The filtered water supply system is also provided with means capable of substantially detecting the concentration of salts of the filtered water.
For producing salt-containing water. 5. The method according to claim 3, wherein the means capable of substantially detecting the concentration of salts comprises a means for detecting electric conductivity.
For producing salt-containing water. 6. The apparatus for producing salt-containing water according to claim 1, wherein said means for preparing salt-containing water has a batch type mixing tank of filtered water and pure water. 7. The apparatus for producing salt-containing water according to claim 1, wherein said means for preparing salt-containing water has a continuous mixing system of filtered water and pure water. 8. The apparatus for producing salt-containing water according to claim 1, wherein the target concentration of salt-containing water is drinking water. 9. Filtration water is produced by a filtration water production device,
Pure water is produced by a pure water production apparatus, and filtered water and pure water are mixed at a predetermined ratio to prepare salt-containing water having a target salt concentration intermediate between the salt concentration of the filtered water and the salt concentration of the pure water. A method for producing salt-containing water.