JPH0557312B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for preventing scale on a toilet drain pipe, and more particularly to a method for preventing scale containing calcium as a main component from adhering to a toilet drain pipe. The method of the present invention can be applied to any type of flush toilet or men's toilet without flush facilities. [Prior Art] Scale called urinary stone, which is a mixture of calcium-based compounds and organic substances produced by the decomposition of urine, is formed in toilet drain pipes, especially in men's restrooms. This impairs the flow of flushing water, and in extreme cases, it blocks the drain pipes, rendering the toilet unusable. Furthermore, organic matter in urinary stones is decomposed by bacteria and produces a foul odor. The foul odor in the men's restroom is a mixture of foul odor from decaying organic matter and ammonia emitted from decomposition of urine. BACKGROUND ART Conventionally, methods for preventing scale in toilet drain pipes have been put into practical use, such as a method in which a chemical is injected into the middle of a flush water pipe, and a method in which a chemical formed into a spherical shape is poured into a toilet bowl in a men's restroom. Various drugs containing surfactants, bactericides, and fragrances have been proposed for use in these methods. For example, a deodorant cleaning agent for flush toilets is made by melt-mixing surfactants, ion sequestering agents, fragrances, etc. with polyethylene glycol or polypropylene glycol and aromatic substances, and then injection molding the mixture.
It is described in Publication No. 45-30706. Further, an automatic flushing toilet cleaning agent containing a nonionic surfactant, ethylene oxide/propylene oxide copolymer, as a main ingredient is described in Japanese Patent Publication No. 17205/1983. Furthermore, as methods for removing scale that has once stuck to the toilet drain pipe, methods have been adopted, such as using a strong inorganic acid such as hydrochloric acid to dissolve the scale, and removing the toilet bowl and mechanically removing the scale. [Problems to be Solved by the Invention] The use of conventionally employed agents consisting of surfactants, disinfectants, and fragrances is effective in preventing stains on the toilet wall surface and in preventing the generation of bad odors. However, the effect of preventing scale from adhering to the toilet drain pipe is not sufficient, and the flow of the disinfectant into the septic tank inhibits the action of bacteria in the septic tank, reducing the purification ability of the septic tank. The use of cleaning and deodorizing agents consisting of surfactants and fragrances is also effective in preventing stains on the toilet bowl wall and in preventing the generation of bad odors. However, the effect of preventing scale from sticking to toilet drain pipes is even smaller. Adding sequestrants to urine or wash water is quite effective in preventing scale build-up. However, in order to completely prevent scale adhesion, ion sequestrant should be added at 0.3 to 1% by weight based on urine.
need to be added. Generally, ion sequestrants are expensive and this method is difficult to widely disseminate. Furthermore, dissolving and removing fixed scale using strong acids and mechanically removing fixed scale by removing the toilet bowl are unpleasant and difficult tasks. In addition, when removing scale using strong acids, corrosion of the drain pipes due to the acid and a decrease in purification ability due to the acid flowing into the septic tank become a problem, while when removing scale mechanically, damage to toilet bowls and drain pipes becomes a problem. An object of the present invention is to provide a simple and economical method for preventing scale from sticking to toilet drain pipes. [Means for Solving the Problems] The present invention solves the problem of urine or mixed wastewater of urine and washing water.
This is a method for preventing scale in toilet drain pipes, which is characterized by adjusting and maintaining the pH between 5 and 8.5. In the present invention, pH adjustment and maintenance of urine or mixed wastewater of urine and wash water is performed by adding an acidic substance to the urine and/or wash water. As the acidic substance, when added to urine or mixed wastewater of urine and washing water, a salt having a solubility in water with a pH range of 5 to 8.5 of 0.01g/100g (water) or less is generated by reacting with calcium ions. What can be used is one that can adjust and maintain the pH of urine or mixed waste water of urine and washing water within the range of 5 to 8.5. For example, mineral acids such as hydrochloric acid, sulfuric acid, and nitric acid; organic acids such as acetic acid, hydroxyacetic acid, succinic acid, benzoic acid, and citric acid; water-soluble acid salts such as sodium hydrogen sulfate, potassium hydrogen sulfate, and ammonium hydrogen sulfate;
Examples include water-soluble salts of strong acids and weak bases such as ammonium chloride and ammonium sulfate, and sulfamic acids. These acidic substances are 1
The species can be used alone or as a mixture of two or more species. As a method and device for adding and dissolving acidic substances into urine and/or washing water, and adjusting and maintaining the pH, a known method and device conventionally used for adding various drugs to toilets is used. be able to. For example, an automatic injector for an aqueous solution of an acidic substance is installed in a toilet's flushing water tank or in the middle of the flushing water pipe, and a fixed amount of an aqueous solution of an acidic substance is injected into the flushing water each time the flushing water flows out. A method of dissolving the acidic substance by placing a molded body containing an acidic substance that is solid at room temperature in a container and placing it in a wash water tank or a wash water flow channel and bringing it into contact with the wash water, and the molded body of,
A method can be adopted in which the acidic substance is dissolved by placing it in the toilet bowl of the men's restroom and bringing it into direct contact with urine or washing water. A more specific method will be explained below. It was proposed in Utility Model Application Publication No. 53-124266, etc., and
An aqueous solution of an acidic substance is filled with a device that injects a certain amount of a liquid substance into the cleaning water tank using the upper and lower water levels of various types of cleaning water tanks that have been put into practical use.The device is then installed in the cleaning water tank. Each time the wash water flows out, a certain amount of an aqueous solution of an acidic substance is injected into the wash water, and the pH of the mixed wastewater of urine and wash water is adjusted and maintained within a certain range. It was proposed in Japanese Utility Model Application No. 51-125840, Japanese Utility Model Application No. 53-134540, etc., and has been put into practical use by connecting it to the middle of the washing water pipe and dispensing a certain amount of liquid chemical every time the washing water flows out. It is also possible to use devices that automatically inject into the wash water. In this case, the pH of the mixed wastewater of urine and wash water can be adjusted and maintained even in a toilet where a wash water tank is not installed. A solid acid was proposed in Japanese Utility Model Application Publication No. 49-133461, Japanese Utility Model Application No. 52-130462, etc., and has been put into practical use. It is possible to accommodate a molded body containing solid acid, etc. as an acidic substance, and install it in a washing water tank to dissolve the solid acid, etc. in the washing water, and adjust and maintain the pH of the mixed wastewater of urine and washing water. . There is also a method in which a molded article containing a solid acid, etc. as an acidic substance is placed in a container, brought into contact with water from a faucet for hand washing, and the water in which the solid acid, etc. is dissolved is stored in a washing water low tank. -143038 Publication, Utility Model Application Publication No. 162154/1983, etc.) and a container containing a molded body containing a solid acid as an acidic substance is installed in the flushing water channel in the toilet bowl, and the solid acid, etc. is removed from the flushing water. (Utility Model Application Publication No. 50-11347,
It is also possible to adjust and maintain the pH of the mixed wastewater of urine and washing water by adopting the method (see Japanese Utility Model Application Publication No. 51-115737, etc.). In methods using aqueous solutions of acidic substances,
By selecting the concentration and injection amount of the aqueous solution, the pH of the mixed wastewater of urine and washing water is adjusted and maintained. If desired, surfactants, fragrances, colorants, corrosion inhibitors, etc. may be added to the aqueous solution of the acidic substance. It is also possible to add a type of bactericidal agent that does not affect bacteria in the septic tank or an amount that has a negligible effect, and an ion sequestering agent that does not cause an economic burden. A molded article containing an acidic substance that is solid at room temperature, such as a solid acid, is a molded article made of the acidic substance, a base material, and optionally added additives. Examples of additives include dissolution rate regulators, surfactants, fragrances, colorants, corrosion inhibitors, bactericides, ion sequestering agents, and the like. Among the above-mentioned acidic substances, various salts, organic acids, and sulfamic acid are used as the acidic substances that are solid at room temperature. As the base material, sublimable substances such as paradichlorobenzene, naphthalene, etc., water-soluble polymers that are solid at room temperature, such as polyethylene glycol, polypropylene glycol, various surfactants, etc. are used. These molded bodies can be produced using known methods such as mixing powder and/or granular components and compressing them into tablets, heating a mixture of the components, and injecting a molten slurry into a mold to cool and solidify. It can be manufactured by the following molding method. As a dissolution rate regulator, a fine powder of a water-repellent substance can be used. For example, calcium stearate, magnesium stearate, etc. are preferably used. By adjusting the dissolution rate, shape, number of molded bodies, etc. used, it is possible to adjust and maintain the pH of urine or mixed wastewater of urine and washing water. The dissolution rate of the molded article can be adjusted by selecting the type and quantitative ratio of the acidic substance used, the base material, etc., and by using a dissolution rate regulator. In particular, in the case of molded products that are placed directly into men's restrooms, it is required that the dissolution rate is appropriate and that they do not undergo significant deformation such as disintegration or swelling upon contact with urine and/or washing water. . The molded products for these uses include a molded product made by compressing a mixture of an acidic substance powder that is solid at room temperature and a fine powder of paradichlorobenzene, and a mixed melt of paradichlorobenzene and a water-soluble polymer mixed with an acidic substance. It is preferable to use a molded body obtained by injecting a slurry in which powders of the above are added and mixed into a desired mold, and cooling and solidifying the slurry. [Function] As a result of intensive research into methods for preventing scale from adhering to toilet drain pipes, the present invention and others have found that the scale is composed of calcium apatite [Ca ₅ (PO ₄ ) ₃ OH].
40~60wt%, calcium carbonate [ _CaCO3 ] 20~
40wt% and water-insoluble organic matter 10-30wt%, calcium-based scale has a PH of
It does not precipitate in water with a pH of 7.5 or less, and very little precipitation occurs in water with a pH in the range of 7.5 to 8.5.Also, it takes a long time to precipitate, and urine or mixed waste water with urine and washing water is Due to the action of urinary degrading enzymes,
The present invention was completed by discovering that ammonia is generated and the pH increases in a short period of time. Water-soluble calcium ions are normally present in urine.
Contains 200 to 300 ppm, and 2000 to 2500 ppm of phosphate ions. In addition, carbonate ions are contained in the washing water, and are replenished by dissolving carbon dioxide gas in the atmosphere. The pH of urine excreted from the body is about 6 to 6.5, but when left in the atmosphere, the pH gradually increases and eventually reaches 9 to 9.5. When the pH is over 7.5, turbidity occurs, and as the pH rises, the turbidity increases.
When the pH exceeds 8.5, a white precipitate of calcium apatite precipitates, and a film of calcium carbonate crystals forms on the surface in contact with the atmosphere. These calcium apatite and calcium carbonate crystals, along with organic matter such as water-insoluble proteins produced by the action of bacteria and enzymes, stick to the toilet drain pipe and grow into scale, commonly called urinary stones. Therefore, by keeping the pH of urine or mixed wastewater of urine and wash water at 8.5 or less, preferably 7.5 or less, it is possible to prevent scale from adhering to the toilet drain pipe. As a method of keeping the pH of urine or mixed wastewater of urine and washing water below 8.5,
A method of dissolving the acidic substance in urine and/or washing water is simple and preferably employed. Toilets may not be used for long periods on holidays, etc., so even during those periods, the pH of urine accumulated in the drain pipes or the mixed wastewater of urine and washing water is adjusted to 8.5.
In order to maintain the pH below, an ammonium salt thereof having a strong acidic group exhibiting PH buffering properties is preferably used as the acidic substance. However, the solubility of the salt produced by reacting with calcium in water is 0.01g/
It is not preferable to use acidic substances that are less than 100g (water). On the other hand, if the pH of urine or mixed waste water of urine and washing water is too low, corrosion of the drain pipe becomes a problem, which is not preferable. Therefore, the preferable lower limit of the pH of urine or mixed wastewater of urine and washing water is 5, more preferably 5.5. [Example] The present invention will be explained in more detail with reference to Examples. However, the scope of the present invention is not limited in any way by the following examples. Example 1 Fresh urine 3 (PH = 6.35) was collected and divided into 6 equal parts, each 500 ml sample was subjected to the following treatment,
Changes in pH and the amount of water-insoluble matter produced were measured.
Each sample was kept at 20±3°C during the measurement period. Sample 1: Continuously inject 1% sulfamic acid aqueous solution from an automatic titrator to adjust the pH to 0.2 ± 0.2.
Hold Sample 2: Continuously inject 1% sulfamic acid aqueous solution from automatic titrator to adjust pH to 8.2 ± 0.2.
Hold Sample 3 (comparison): Continuously inject 1% sulfamic acid aqueous solution from an automatic titrator to adjust the pH to 8.8 ± 0.2 and hold Sample 4 (comparison): Disinfectant; benzalkonium chloride
Added 0.5g Sample 5 (comparison): Untreated Table 1 shows the change in pH of each sample over time and the amount of water-insoluble matter produced (g/).

[Table] Example 2 Three men's urinals are regularly flushed once an hour with flush water from 10 flush water tanks. Each urinal in five toilets is flushed with a corrosion inhibitor. It was washed with hydrochloric acid and treated to prevent scale from sticking by the following method. Specification 1: A commercially available chemical supply container designed to supply 0.6 ml of liquid chemical to the cleaning water tank every time the cleaning water flows out, a corrosion inhibitor containing a cationic surfactant in 35% hydrochloric acid ( The tank was filled with a chemical containing 1% of Ibit (manufactured by Asahi Chemical Co., Ltd.) and placed in the washing water tank, and the chemical was periodically supplied into the washing water. Specification 2: A mixture consisting of 60 parts by weight of sulfamic acid powder, 40 parts by weight of fine paradichlorobenzene powder, and 2 parts by weight of calcium stearate was pressure-molded and three spherical molded bodies with a diameter of 40 mm were placed in a urinal. , dissolved in urine and wash water. Specification 3 (comparison): A drug supply container with the same specifications as the drug supply container used in Specification 1, disinfectant benzalkonium chloride; 20% and ethylene oxide.
Filled with an aqueous solution containing 10% propylene oxide copolymer (nonionic surfactant);
It was installed in the washing water tank, and the chemical was periodically supplied into the washing water. Specification 4 (comparison) One spherical molded product with a diameter of 40 mm manufactured by heating and melting an ethylene oxide-propylene oxide copolymer (nonionic surfactant) that is solid at room temperature, injecting it into a mold, and then cooling and solidifying it. was placed in the urinal and dissolved in the urine and wash water. Specification 5 (comparison): Blank. A cylindrical test piece made of stainless steel wire mesh and a piece of iron measuring 20 mm x 70 mm x 1 mm were installed in the trap section under the perforated plate of each toilet bowl, and the amount of scale adhering to the wire mesh and the amount of corrosion of the iron piece was measured. In addition, the mixed wastewater of urine and washing water in the trap is
PH, PH and COD of septic tank water were measured before using the drug and 1 week after starting using the drug. To eliminate errors due to the frequency of toilet use, the test piece, iron piece, and drug were changed every three weeks, and tests were conducted in all five toilets for three weeks each. For Specifications 1 and 3, drugs were replenished every 3 weeks. For specifications 2 and 4, the drug weight is the initial value.
When the percentage decreased to below 20%, a new drug was added. The results of each measurement are shown in Table 2. In Table 2, each symbol represents the following. Toilet wall stains: ◎; No stains 〇; Almost no stains △; Slight stains ×; Stains and foul odor: ◎; No foul odor 〇; Almost no foul odor △; Slightly foul odor ×; Offensive odor

〔Effect of the invention〕

In the present invention, as shown in Example 1 above, when the pH of urine is 8.5 or less, very little precipitate is formed, and when the pH is 7.5 or less, almost no precipitate is formed. Therefore, by adjusting and maintaining the pH of urine or mixed wastewater of urine and wash water at 8.5 or less, preferably 7.5 or less, scale and adhesion to the toilet drain pipe can be prevented. This is even clearer in the specific example of a urinal in a men's restroom shown in Example 2. Further, in the method of the present invention, corrosion of the drain pipe is extremely small and does not adversely affect the function of the septic tank. In the example, a specific example was shown in a men's toilet with a cleaning device, but similar results can be obtained in a men's toilet without a cleaning device and a unisex toilet with a cleaning device. The present invention provides a simple method for preventing scale buildup in toilet drain pipes, and has extremely great public health and industrial significance.

Claims (1)

[Claims] 1. Adding acidic substances to urine and/or washing water to raise the pH of urine or mixed wastewater of urine and washing water to 5 to 5.
A method for preventing scale in toilet drain pipes, which is characterized by maintaining the level at 7.5. 2. The method for preventing scale in toilet drain pipes according to claim 1, wherein the acidic substance is mineral acids, organic acids, water-soluble acid salts, water-soluble salts of strong acids and weak bases, and sulfamic acid. 3. Install an automatic injection device for aqueous solutions of acidic substances in the flush water tank of the toilet or in the middle of the flush water piping.
A method for preventing scale in a toilet drain pipe according to claim 1, wherein an aqueous solution of an acidic substance is injected into the wash water every time the wash water flows out. 4. The method for preventing scale in a toilet drain pipe according to claim 1, wherein a molded article containing a solid acid as an active ingredient is housed in a container and installed in a wash water tank or a wash water flow channel. 5. A method for preventing scaling of a toilet drain pipe according to claim 1, wherein a molded article containing a solid acid as an active ingredient is placed in a men's toilet bowl.