JP2011174786A - Hardness measuring reagent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hardness measuring reagent for efficiently measuring test water, especially, the hardness of unsterilized test water, by using a device having a compact structure. <P>SOLUTION: The hardness measuring reagent contains (1) a hardness measuring reagent, containing a pigment component containing Eriochrome Black T and/or calmagite, and a bacteriostatic agent component containing benzoic acid or its salt, and/or para hydroxybenzoic acid ester; and (2) a hardness measuring reagent comprising a combination of a first reagent including a pigment component containing Eriochrome Black T and/or calmagite; and a second reagent containing a bacteriostatic agent component that contains benzoic acid or its salt and/or parahydroxybenzoic acid ester. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hardness measuring reagent, and more particularly to a reagent for measuring the hardness of sample water that has not been sterilized.

  Conventionally, equipment for removing hardness components contained in raw water from the viewpoint of preventing scale adhesion in the equipment for cooling equipment such as boiler water supply equipment and coolers, or for pretreatment of pure water equipment Is connected. For example, soft water obtained by connecting a water softener using ion exchange resin and replacing hardness components with Na ions is used as water supply.

This ion exchange resin may leak hardness components due to poor regeneration or deterioration of the ion exchange resin. Therefore, when leakage of hardness components is monitored and the allowable concentration of hardness is exceeded, measures such as regeneration and maintenance of the ion exchange resin are required. In order to make the determination, it is necessary to monitor the hardness of the water to be treated. Generally, the hue is measured using a hardness measuring reagent containing the dye Eriochrome Black T (hereinafter sometimes abbreviated as EBT). (See, for example, Patent Documents 1, 2, and 3).
In this case, the hue of the test water is determined by the abundance ratio between the chelate compound produced by the reaction between the hardness component and the dye contained in the hardness measurement reagent and the unreacted (free) dye. Specifically, when EBT is used as the pigment, as the hardness in the test water increases, the color of the test water changes from the original blue color to blue-violet, and further passes reddish purple to red.

Monitoring of the hardness component leak is usually carried out continuously or periodically using an automatic measuring device, but in water supply that has not been sterilized, the hardness measurement cell is contaminated due to the growth of microorganisms. May cause problems.
In order to prevent contamination by microorganisms, sterilization with sodium hypochlorite is used as a method of sterilizing the water supply itself. If the residual chlorine concentration due to sodium hypochlorite is high, the color of Eriochrome Black T is developed. Have been pointed out, and a method of using a reducing agent and other additives in order to eliminate the influence of residual chlorine has been disclosed (for example, see Patent Documents 4 and 5).

When using a reagent that combines a dye and an oxidizing disinfectant such as sodium hypochlorite as a hardness indicator in order to prevent the hardness measurement cell from being contaminated by the growth of microorganisms in the hardness measurement of test water Since the coloring matter reacts with the oxidizing bactericidal agent and is affected by color development, it cannot be a one-pack type hardness indicator containing the coloring matter and sodium hypochlorite as the oxidizing bactericidal agent. Therefore, there is no choice but to use a two-pack type combination of the reagent containing the dye and the reagent containing the bactericidal agent, and the hardness measuring device becomes complicated and the cost of hardness measurement is unavoidable. Occurs.
On the other hand, in order to prevent the invasion of microorganisms into the measuring device, a method of removing by using an MF (microfiltration) membrane or hollow fiber membrane of about 0.1 μm is known. However, if microorganisms are mixed for some reason even once, they may gradually grow in the measuring instrument and cause similar troubles.

Japanese Patent Laid-Open No. 11-64323 JP 2002-181802 A JP 2002-181803 A JP 2005-283399 A JP 2005-283401 A

In this way, in the hardness measurement of test water, particularly test water that has not been subjected to sterilization treatment, in order to suppress obstacles due to the growth of microorganisms, the sterilization treatment of test water and the application of membranes such as MF membranes to some extent Although the obstacle can be alleviated, the hardness measurement apparatus becomes large and the above application is difficult.
In addition, by using a membrane such as an MF membrane, it is possible to suppress the introduction of microorganisms and to suppress the damage caused by microorganisms. However, in the case where the membrane is damaged or the introduction of microorganisms from the opening occurs. In addition to this, regular maintenance of the membrane is required.

Furthermore, when using an oxidizing sodium hypochlorite that is a normal disinfectant as one component of the hardness indicator, if this disinfectant and a pigment that is another component are used in a one-pack type, Since the dye reacts with the bactericide and is affected by the color development, it has to be a two-component type, and the hardness measuring apparatus becomes complicated, resulting in a problem that the cost of hardness measurement is high.
The present invention has been made under such circumstances, and provides a hardness measuring reagent for efficiently measuring the hardness of test water, particularly test water that has not been sterilized, using a device having a compact structure. The purpose is to provide.

As a result of intensive studies to achieve the above object, the present inventor can make a one-component type by using a pigment component containing a specific pigment and a bacteriostatic component containing a specific compound. And found that the purpose can be achieved. The present invention has been completed based on such findings.
That is, the present invention provides the following (1) to (5).
(1) a reagent for hardness measurement, comprising a pigment component comprising Eriochrome Black T and / or karmagite, and a bacteriostatic component comprising benzoic acid or a salt thereof and / or p-hydroxybenzoic acid ester,
(2) The hardness measuring reagent according to (1), further comprising at least one selected from triethanolamine, alkyl alcohol, and glycol,
(3) A first reagent containing a pigment component containing Eriochrome Black T and / or Calmagite, and a second reagent containing an antibacterial component containing benzoic acid or a salt thereof and / or p-hydroxybenzoic acid ester A combination of hardness measuring reagents,
(4) The hardness measuring reagent according to (3) above, wherein the first reagent and / or the second reagent further contains at least one selected from triethanolamine, alkyl alcohol and glycol, and (5) The reagent for hardness measurement according to any one of the above (1) to (4), which is applied to test water that has not been sterilized.

The hardness measuring reagent of the present invention has the following effects.
(1) The hardness of test water, particularly test water that has not been sterilized, can be efficiently measured using an apparatus having a compact structure.
(2) Since the growth of microorganisms can be effectively suppressed, the hardness measurement cell can be maintained in a clear state over a long period of time, and operations such as cleaning and replacement are reduced.
(3) There is no need to disinfect and sterilize the test water itself or introduce equipment.
(4) Monitor the leakage of hardness components to the soft water treated water caused by poor regeneration or deterioration of the ion exchange resin used in the hard water softener, and if the hardness component of the soft water treated water exceeds the allowable concentration, Measures such as regeneration and maintenance of the ion exchange resin can be effectively performed.

It is a schematic diagram of the apparatus for a test for measuring the hardness of test water using the reagent for one-pack type hardness measurement.

  The hardness measuring reagent of the present invention has two aspects of the following (1) one-component reagent and the following (2) two-component reagent, that is, (1) a dye component containing eriochrome black T and / or karmagite And a bactericide component containing benzoic acid or a salt thereof and / or a p-hydroxybenzoic acid ester (one-component type) [hereinafter referred to as a one-component type hardness measuring reagent. And (2) a second reagent containing a first reagent containing a pigment component containing Erio Black T and / or karmagite, and an antibacterial component containing benzoic acid or a salt thereof and / or p-hydroxybenzoic acid ester Reagent for hardness measurement (two-component type) consisting of a combination with a reagent [hereinafter referred to as a two-component hardness measurement reagent. ].

[Dye component]
In the first reagent of the one-component hardness measurement reagent and the two-component hardness measurement reagent of the present invention, as a pigment component, Eriochrome Black T (Eriochrome Black T) represented by the following formula (1) and / or Or what contains the calmagite (Calmagite) represented by following formula (2) is used.

(Eriochrome Black T and Karmagite)
In the present invention, Eriochrome Black T used as a dye component has a structure represented by the above formula (1), (1-hydroxy-2-naphthylazo) -6-nitro-2-naphthol-4-sulfonic acid sodium salt Karmagite is 3-hydroxy-4-[(2-hydroxy-5-methylphenyl) azo] -1-naphthalenesulfonic acid having the structure represented by the formula (2).
This eriochrome black T or karmagite is a pigment that changes its color clearly from blue to red by forming a chelate compound with a hardness component in the alkaline pH region, and can be used alone or in combination. The blending ratio of the dye is not particularly limited, and is usually 0.1 to 1.0% by mass, preferably 0.1 to 0.5% by mass in the reagent for measuring hardness. By setting the blending ratio of the dye within this range, even if residual chlorine is present in the test water, the test water can have a hue corresponding to the actual hardness regardless of the residual chlorine concentration. .

[Antimicrobial component]
In the one-component hardness measuring reagent and the second-component hardness measuring reagent of the present invention, those containing benzoic acid or a salt thereof and / or a p-hydroxybenzoic acid ester as an antibacterial component. Used.
Examples of the benzoic acid salt include sodium salts and potassium salts. Examples of the p-hydroxybenzoic acid ester include compounds represented by the following general formula (3).

(In the formula, R represents an alkyl group having 1 to 5 carbon atoms or an aralkyl group having 7 to 10 carbon atoms.)

In the general formula (3), the alkyl group having 1 to 5 carbon atoms in R may be linear, branched or cyclic, for example, a methyl group, an ethyl group, an n-propyl group, An isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, various pentyl groups, a cyclopentyl group, and the like are mentioned. On the other hand, as an aralkyl group having 7 to 10 carbon atoms, a benzyl group, a methylbenzyl group Phenethyl group, methylphenethyl group, phenylpropyl group and the like.
Examples of the p-hydroxybenzoic acid ester represented by the general formula (3) include methyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, isopropyl p-hydroxybenzoate, butyl p-hydroxybenzoate, p- Examples thereof include isobutyl hydroxybenzoate and benzyl p-hydroxybenzoate.

In the second reagent of the one-component hardness measurement reagent and the two-component hardness measurement reagent of the present invention, as an antibacterial component, among the above-described benzoic acid, benzoate and p-hydroxybenzoate ester, One type may be selected and used, or two or more types may be selected and used.
This antibacterial component is desirably used so that the content in the total amount of the hardness measuring reagent is preferably 0.5 to 10% by mass, more preferably 1 to 5% by mass. By using such an amount, even if the reagent is diluted about 20 to 500 times with test water, the effect of suppressing the growth of microorganisms in the test water and preventing contamination of the hardness measuring cell is obtained. Play.

[Other ingredients]
The one-component hardness measuring reagent and the two-component hardness measuring reagent of the present invention contain at least one selected from triethanolamine, alkyl alcohol and glycol in addition to the dye component and the antibacterial component described above. be able to.
In the case of a two-component hardness measurement reagent, the other components can be contained in the first reagent and / or the second reagent.

(Triethanolamine)
Triethanolamine is used to maintain the pH of the test water at around 10 and stabilize the color development of the dye described above. The mixing ratio of triethanolamine is not particularly limited, and is preferably an amount contained in the total amount of the hardness measuring reagent in a proportion of preferably 20 to 90% by mass, more preferably 40 to 80% by mass.
By including triethanolamine in such an amount, the pH of the test water is maintained at around 10 even when the hardness measurement reagent is diluted about 20 to 500 times with the test water, as described above. It has the effect of stabilizing the coloring of the dye.

(Alkyl alcohol, glycol)
Alkyl alcohol and glycol are components used as a solvent or an antifreeze for the hardness measurement reagent of the present invention. Examples of the alkyl alcohol include ethanol, n-propanol, and isopropanol. On the other hand, examples of the glycol include ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol.
In the present invention, the alkyl alcohol or glycol may be used alone or in combination of two or more.
Although there is no restriction | limiting in particular about the compounding quantity of the said alkyl alcohol and glycol, From a viewpoint of the effect | action as a solvent or an antifreeze, Preferably it is 5-70 mass% in the whole quantity of the said reagent for hardness measurement, More preferably, it is 15-50 mass. It is desirable that the amount be contained in a percentage.

[Other optional additives]
In the one-component hardness measurement reagent and the two-component hardness measurement reagent of the present invention, in addition to the dye component, antibacterial component and other components described above, as long as the effects of the present invention are not impaired, as necessary. In addition, other optional additives such as residual chlorine fixing component, reducing agent, pH buffering agent, chelating agent, masking agent, sensitizer, deterioration preventing agent, antifoaming agent and the like can be appropriately contained.

(Residual chlorine fixation component)
When the test water is sterilized with a chlorine-based disinfectant such as sodium hypochlorite, residual chlorine may exist in the test water. If the residual chlorine concentration is about 1.5 mg / L or more in the test water, the color development of the hardness measurement reagent using the dye may be hindered.
Therefore, when residual chlorine is contained in the test water at the above concentration, it is advantageous to contain a residual chlorine immobilization component in the hardness measuring reagent.

  This residual chlorine immobilization component is a compound that reacts with residual chlorine to produce bound chlorine such as chloramine, chloroimine, chloroimide, and the like. Examples of the residual chlorine immobilization component include primary amines, secondary amines, salts thereof, and ammonium salts, and these can be used alone or in combination of two or more. Examples of primary amines include alkyl alcohol amines (eg, monoethanolamine), linear alkylamines (eg, butylamine), cyclic alkylamines (eg, cyclohexylamine), aromatic amines (eg, aniline), amino acids, and the like. Can be mentioned. Secondary amines include, for example, alkyl alcohol amines (eg, diethanolamine), linear alkylamines (eg, diethylamine), cyclic alkylamines (eg, azacyclohexane [piperidine]), aromatic amines (eg, diphenylamine), amino acids Etc. Among these, alkyl alcohol amines (for example, monoethanolamine, diethanolamine) are particularly preferable from the viewpoint of ensuring the color stability of the test water corresponding to the hardness in the test water without being affected by the residual chlorine concentration.

The blending ratio of the residual chlorine fixing component is not particularly limited, and is usually 0.3 to 3.0% by mass, preferably 0.5 to 2.0% by mass in the hardness measuring reagent of the present invention. By setting the blending ratio of the residual chlorine fixing component within such a range, the test water can have a hue corresponding to the actual hardness regardless of the residual chlorine concentration.
In the two-component hardness measurement reagent of the present invention, the residual chlorine immobilization component can be contained in the first reagent and / or the second reagent.

(Reducing agent)
This reducing agent, like the above-mentioned residual chlorine immobilization component, suppresses interference with the color of the hardness measuring reagent using the dye due to the residual chlorine when residual chlorine is present in the test water. It is a drug used for this purpose.
Examples of the reducing agent include hydroxylamine hydrochloride, ascorbic acid, hydroquinone, cobalt sulfate, sodium isoascorbate, sodium thiosulfate, hydrosulfite, sodium sulfite, tin chloride, ammonium sulfite, methyl ethyl ketoxime, Rongalite, glucose and the like. These can be used alone or in combination of two or more. By using a hardness measuring reagent containing a reducing agent having such a reducing action, the test water can be made to have a hue corresponding to the actual hardness regardless of the residual chlorine concentration.

Although there is no restriction | limiting in particular about the compounding quantity of the said reducing agent, Preferably it is 0.3-3.0 mass% in the whole quantity of the reagent for hardness measurement of this invention, More preferably, it is 0.5-2.0 mass%. It is desirable that the amount be included in proportion.
When the reducing agent is used in the one-component hardness measuring reagent of the present invention, an antibacterial component, preferably at least one component selected from triethanolamine, alkyl alcohol and glycol, and as necessary It is advantageous to prepare a one-component type by mixing the various additive components used in the above, and then adding the pigment component thereto.
On the other hand, when the reducing agent is used in the two-component hardness measurement reagent of the present invention, it is advantageous that the second reagent contains the reducing agent.

(PH buffer)
This pH buffering agent is a chemical for maintaining the pH of the test water at a desired value regardless of the level of M alkalinity in the test water and stabilizing the color development of the hardness measuring reagent containing the dye. It can be used in any one-component and two-component hardness measuring reagents.
The pH buffer is preferably a combination of an amine selected from primary amines or secondary amines and a salt of a weak base. Examples of primary amines include alkyl alcohol amines (eg, monoethanolamine), linear alkylamines (eg, butylamine), cyclic alkylamines (eg, cyclohexylamine), aromatic amines (eg, aniline), amino acids, and the like. Can be mentioned. Secondary amines include, for example, alkyl alcohol amines (eg, diethanolamine), linear alkylamines (eg, diethylamine), cyclic alkylamines (eg, azacyclohexane [piperidine]), aromatic amines (eg, diphenylamine), amino acids Etc. Among these, alkyl alcohol amines (for example, monoethanolamine and diethanolamine) are preferable from the viewpoint of color stability of the test water.

  Examples of weak base salts include ammonium salts, primary amine salts, and secondary amine salts. Examples of ammonium salts include ammonium chloride, ammonium acetate, ammonium sulfate, ammonium bromide, and ammonium oxalate. Examples of primary amine salts include alkyl alcohol amines (eg, monoethanolamine), linear alkylamines (eg, butylamine), cyclic alkylamines (eg, cyclohexylamine), aromatic amines (eg, aniline), amino acids, etc. (For example, hydrochloride, sulfate, acetate, oxalate, etc.). Secondary amine salts include, for example, alkyl alcohol amines (eg, diethanolamine), linear alkyl amines (eg, diethylamine), cyclic alkylamines (eg, azacyclohexane [piperidine]), aromatic amines (eg, diphenylamine), amino acids Acid salts (for example, hydrochloride, sulfate, acetate, oxalate, etc.).

The combination of the amine and the weak base salt is not particularly limited, but an alkyl alcohol amine-ammonium salt is preferably used from the viewpoint of the color stability of the test water.
Although there is no restriction | limiting in particular about the compounding quantity of the said pH buffer agent, From a viewpoint which does not inhibit the effect | action which another component has, Preferably it is 5-50 mass% in the whole quantity of the reagent for hardness measurement of this invention, More preferably, it is 10 It is desirable that the amount is contained at a ratio of ˜40 mass%.
In the two-component hardness measurement reagent of the present invention, the pH buffer can be contained in the first reagent and / or the second reagent.

(Chelating agent)
This chelating agent is a chemical for the test water to be sensitively discolored by the hardness measuring reagent of the present invention in the vicinity of the controlled hardness, thereby reliably discriminating leakage of hardness components. It can be used in any liquid-type hardness measurement reagent.
As the chelating agent, an organic chelating agent or an inorganic chelating agent can be used. Examples of organic chelating agents include ethylenediaminetetraacetic acid (EDTA), trans-1,2-diaminocyclohexanetetraacetic acid (CyDTA), o, o′-bis (2-aminoethyl) ethylene glycol tetraacetic acid (GEDTA), and the like. Examples include alkali metal salts such as aminocarboxylic acid, citric acid, and gluconic acid, and these can be used alone or in combination of two or more. Examples of inorganic chelating agents include known alkali metal salts of phosphoric acid compounds such as pyrophosphoric acid, polyphosphoric acid, and metaphosphoric acid. Among these, an organic chelating agent is preferable from the viewpoint of chelating ability to react preferentially with the hardness component as compared with the dye, and among the organic chelating agents, an alkali metal salt of aminocarboxylic acid is preferable. Among the alkali metal salts of aminocarboxylic acid, the alkali metal salt of EDTA is particularly preferable from the viewpoint of the chelate-forming ability and economy.

  Examples of the alkali metal constituting the alkali metal salt of the chelating agent include Na and K. Examples of the alkali metal salt of EDTA include EDTA-Na, EDTA-K, EDTA-2Na, EDTA-2K, EDTA-3Na, EDTA-3K, EDTA-4Na, and EDTA-4K. Among these, From the viewpoint of excellent solubility when added to the test water, EDTA-2Na, EDTA-3Na and EDTA-4Na are particularly preferable.

Although there is no restriction | limiting in particular about the compounding quantity of the said chelating agent, From the viewpoint of changing a test water sharply in the vicinity of management hardness, [management hardness -0.1-2.0 ppm] equivalent addition can be carried out in test water, It is preferably contained in the hardness measuring reagent of the present invention.
In the two-component hardness measurement reagent of the present invention, the chelating agent can be contained in the first reagent and / or the second reagent.

In the hardness measurement reagent of the present invention, in addition to the residual chlorine fixing component, the reducing agent, the pH buffering agent and the chelating agent described above, a masking agent, a sensitizer, a deterioration preventing agent, an antifoaming agent, etc. Additives can be included.
The masking agent stabilizes the color development of the test water by forming a complex with interfering ions (for example, Fe, Mn, Al, etc.) in the test water, and examples thereof include triethanolamine, KCN, Among these, triethanolamine is preferably used from the viewpoint of safety when drained. The sensitizer is for sensitizing the color development of the test water by substituting Ca ²⁺ in the test water with Mg ²⁺ , and for example, EDTA-Mg is preferably used. The deterioration preventing agent prevents the deterioration of the dye even when the hardness measurement reagent is placed at a high temperature of 50 ° C. or higher. For example, potassium sorbate is preferably used. The antifoaming agent is for defoaming bubbles in the test water contained in the measurement container, and for example, a nonionic surfactant is preferably used.
In the two-component hardness measurement reagent of the present invention, these additives used as necessary can be contained in the first reagent and / or the second reagent.

The form of the hardness measuring reagent of the present invention is usually used as a one-component type containing a dye component, an antibacterial agent component, and other components used as necessary. It can be used as a two-pack type consisting of a combination of a first reagent that may contain other components and a bacteriostatic agent component and a second reagent that may contain other components as required. In the case of the two-pack type, the first reagent and the second reagent are added to the test water when the hardness of the test water is measured.
The hardness measurement of the test water using the hardness measurement reagent of the present invention is performed by observing a change in the hue of the test water. The change in the hue is measured by visual observation or color measurement using a spectrophotometer. Etc.
The hue of the sample water is determined by the abundance ratio of the chelate compound produced by the reaction between the hardness component and the dye contained in the reagent for measuring hardness of the present invention and the unreacted (free) dye. Specifically, when EBT is used as the dye, the hue of the test water changes from blue to blue-purple as the hardness in the test water increases, and further passes reddish purple to red.

The hardness measurement reagent of the present invention monitors the leakage of hardness components to the soft water treated water caused by, for example, defective regeneration or deterioration of the ion exchange resin used in the hard water softener, and the hardness component of the soft water treated water has an allowable concentration. In the case of exceeding the above, it is used for taking measures such as regeneration and maintenance of the ion exchange resin.
In addition, the hardness inspection target is not limited to the soft water treated water that has passed through the hard water softening device, but the hardness of the raw water before passing through the hard water softening device, The hardness of water supply, the water in a cold / hot water system, or boiler water can be mentioned.
The hardness measuring reagent of the present invention is particularly effective when applied to test water that has not been sterilized.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
FIG. 1 is a schematic diagram of a test apparatus for measuring the hardness of test water using a one-component hardness measurement reagent in Examples and Comparative Examples. The test apparatus is provided with a line 11 for supplying the water in the water test tank 1 to the hardness measuring cell 2 via the constant flow electromagnetic valve 5 and the flow meter 8. A line 12 for supplying the reagent in the liquid hardness measuring reagent tank 3 to the hardness measuring cell 2 via the pump 7 is provided.
The hardness measuring cell 2 is provided with a transparent window 9 and a liquid level sensor 10, and a stirrer (not shown) rotated by a stirrer 4 is provided at the bottom. The water sample after the hardness measurement in the hardness measuring cell 2 is discharged through the line 13 via the electromagnetic valve 6.

Examples 1 to 4 and Comparative Examples 1 and 2
(1) Preparation of Reagents for Measuring Each One-Component Hardness One-component reagents 1 to 5 having the composition shown in Table 1 were prepared. Reagent 1 is for a comparative example, and reagents 2 to 5 are for an example.

[note]
1) EBT: Eriochrome Black T
2) Propylparaben: propyl p-hydroxybenzoate 3) Benzylparaben: benzyl p-hydroxybenzoate

(2) Hardness measurement of test water As test water, non-sterilized well water was softened as raw water.
In Comparative Example 1 and Examples 1 to 4, the following operations were performed.
(1) First, the constant flow solenoid valve 5 is opened, and the test water in the test water tank 1 is introduced into the hardness measuring cell 2 having a capacity of 30 mL through the flow meter 8 and the line 11. When the liquid volume was detected and the liquid volume reached 20 mL, the constant flow solenoid valve 5 was closed.
(2) Next, the reagent in the hardness measurement reagent tank 3 is added to the test water in the hardness measurement cell 2 through the pump 7 so as to be 100 μL. Rotate and mix with stirring.
(3) Next, after sufficiently stirring and mixing, the color tone of the test water was measured from the transparent window 9 provided in the hardness measuring cell 2 by a color tone analyzer manufactured using a white LED and an RGB photosensor.
(4) Thereafter, the hardness measurement cell 2 was repeatedly drained and supplied with test water 10 times, and the inside of the cell 2 was sufficiently washed.
(5) The above operations (1) to (4) were repeated every 5 minutes.
The above operation was continuously carried out, and the appearance of the hardness measuring cell 2 after 2 weeks, 4 weeks and 6 weeks was confirmed. The results are shown in Table 2.

  Further, in Comparative Example 2, after the test of Comparative Example 1, the above operation (4) was performed to thoroughly wash the hardness measuring cell 2, and then a 0.1 μm hollow was placed in front of the constant flow solenoid valve 5. A yarn filter [manufactured by KITZ Micro Filter, trade name “Polyfix”] was installed, and the same operation as in Comparative Example 1 was performed. The results are shown in Table 2.

Reference Example The following experiment was conducted in order to examine the influence of the addition of p-hydroxybenzoic acid ester to the hardness measurement reagent on the hardness measurement.
Using the one-component reagents 1 to 5 shown in Table 1, each reagent is added at a ratio of 0.5% by mass with respect to the test water whose hardness is adjusted, and the color tone of each appearance is analyzed by a color tone analyzer. (Measured above). The results are shown in Table 3.

[note]
1) Hardness: The unit is mgCaCO ₃ / L. Calcium chloride dihydrate and magnesium chloride hexahydrate were adjusted by dissolving in soft water so that the ratio of calcium hardness to magnesium hardness was 2: 1. Soft water is water obtained by passing Na ion-type ion exchange resin through Noki-cho, Shimotsuga-gun, Tochigi Prefecture, replacing magnesium ions and calcium ions with Na ions, and the concentration is 0.1 mg CaCO ₃ as hardness. / L was confirmed to be used.
Although the discoloration range shifted slightly, it was confirmed that it can be used without any problem for the measurement of hardness concentration.

  The hardness measuring reagent of the present invention can efficiently measure the hardness of test water, particularly test water that has not been sterilized, using a device having a compact structure, for example, used in a hard water softening device. The leakage of the hardness component to the soft water treated water caused by poor regeneration or deterioration of the ion exchange resin is monitored, and if the hardness component of the soft water treated water exceeds the allowable concentration, the ion exchange resin is regenerated or maintained. It is used to take measures such as.

DESCRIPTION OF SYMBOLS 1 Test water tank 2 Hardness measurement cell 3 Single-component hardness measurement reagent tank 4 Stirrer 5 Constant flow solenoid valve 6 Test water discharge solenoid valve 7 Pump 8 Flow meter 9 Transparent window 10 Liquid level sensor 11 Test water supply line 12 Reagent supply line for hardness measurement 13 Sample discharge line

Claims (5)

  A reagent for measuring hardness, comprising a pigment component containing Eriochrome Black T and / or karmagite and an antibacterial component containing benzoic acid or a salt thereof and / or p-hydroxybenzoic acid ester.   Furthermore, the reagent for hardness measurement of Claim 1 containing at least 1 sort (s) chosen from a triethanolamine, an alkyl alcohol, and glycol.   From a combination of a first reagent containing a pigment component containing Eriochrome Black T and / or Karmagite and a second reagent containing an antibacterial component containing benzoic acid or a salt thereof and / or p-hydroxybenzoic acid ester A reagent for hardness measurement.   The reagent for hardness measurement according to claim 3, wherein the first reagent and / or the second reagent further contains at least one selected from triethanolamine, alkyl alcohol and glycol.   The reagent for measuring hardness according to any one of claims 1 to 4, which is applied to test water that has not been sterilized.

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