JP2005028304A - Method for sterilizing and cleaning water supply pipeline - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipeline cleaning method capable of shortening execution time by stopping reddish water in a short period of time in the case that red rust is stuck to a pipeline inner wall. <P>SOLUTION: In the sterilizing and cleaning method of a water supply pipeline for city water to the inner wall of which the red rust is stuck, after the rust is exfoliated by bringing aqueous acid into contact with the pipeline inner wall, high pressure water containing a sterilizer is supplied, the reddish water is stopped in a short period of time and the rust and organic matters (slime) are effectively removed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a water supply pipe for a water supply from a water meter to a water faucet of an apartment house such as a detached house or a condominium and a water supply pipe for a water supply (hereinafter referred to as a water supply pipe branched from a common water supply pipe such as a commercial building). More specifically, the present invention relates to a method for sterilizing and cleaning water supply pipes having red rust attached to the inner wall of the pipe.

  Inside the water supply pipe installed in the building, rust, humps, slime, etc. are generated when used for a long period of time, which not only inhibits the flow of tap water, but also reduces the taste of food and hygienically It is well known that it does harm.

  Conventionally, as a method for cleaning and removing rust, humps, slime, etc., there are advantages such as simplicity of the method and sanitary safety, and therefore, an ozone cleaning method has been frequently used. In other words, since the ozone cleaning method can be cleaned in a short time, not only the construction cost is low, but also the water shut-off period is shortened, so the burden on the contractor is reduced and ozone is self-decomposed into oxygen. This is because it was a safe method without worrying about environmental pollution.

  FIG. 1 shows the above-described conventional method, and shows an example of the arrangement of devices in the conventional method for cleaning the water supply pipe 9 that branches from the water main 1 and reaches the water tap 10 installed.

  In this conventional construction method, after the device arrangement is completed, the on-off valve 2 is opened and tap water is allowed to flow from the water tap 10, and then ozone water is formed from the ozone gas generated by the ozone generator 7 using the ozone mixer 4 for a certain period of time. Ozone water is passed to oxidize and decompose slime inside piping. After that, while flowing ozone water, intermittently injected compressed air from the air compressor (air compressor) 6 through the compressed air input device 5, by high-speed flowing water formed by the compressed air or mechanical force due to turbulent flow, It removes slime, rust, etc.

  The purpose of flowing ozone water with the conventional water supply pipe cleaning method is to make ozone water contact with the inner wall of the pipe and to use slime formed by organic matter generated by bacteria and bacteria that live inside the water supply pipe using the oxidizing power of ozone. It is for oxidative decomposition.

  The purpose of intermittently supplying (injecting) compressed air while flowing ozone water is to peel and remove slime and rust bumps that have undergone oxidative decomposition by high-speed flowing water created by compressed air or mechanical force due to turbulent flow. It is to do.

  However, ozone water is effective in oxidizing and decomposing slime formed of organic matter, but it is less effective for red rust (maghemite) adhering to the inner wall of the pipe, and it is washed with ozone water until the red water stops (rust can be removed) If it is repeatedly performed, construction time of about 8 hours is required, but this construction time has a problem that the profit of the construction contractor cannot be realized economically. Not only that, even if red water stops on the construction day, red water may appear again in the next morning (after the water has accumulated), but it is not only necessary to work again. In the worst case where red water does not stop even after repeated operations, there is a problem that the piping may be replaced.

  The present invention is intended to solve such problems, and provides a pipe cleaning method capable of shortening the construction time by stopping red water in a short time when red rust adheres to the inner wall of the pipe. Objective.

  The configuration of the present invention that meets the above-mentioned object includes a step of bringing an aqueous acid solution into contact with the inner wall of the pipe and removing the rust in the sterilizing and washing method of the water supply pipe having red rust on the inner wall of the pipe, and a bactericide. And a step of supplying high-pressure water.

  In short, the gist of the present invention is not only to peel and remove red rust, but also to stop red water effectively in a short period of time so that it can be immediately used for daily life.

  It is preferable that the high-pressure water is supplied in a turbulent flow for discharging the aqueous acid solution from the dead end portion of the existing pipe and physically separating the deposits (Claim 2). Turbulence can also be formed by intermittent supply, for example by opening and closing a valve.

  It is preferable to carry out the step of peeling rust at 30 to 60 ° C. (Claim 3).

  The step of bringing the acid aqueous solution into contact with the inner wall of the pipe to remove rust is preferably performed at a pH of 2 or less.

  The acid used is one or more selected from the group consisting of citric acid, lactic acid, adipic acid, succinic acid, glyconodelta lactone, gluconic acid, fumaric acid, DL-malic acid, tartaric acid, acetic acid and electrolyzed water. (Claim 5).

  It is particularly preferable to use citric acid as the acid (claim 6).

  When the cleaning method of the present invention is applied to cleaning of a water supply pipe where corrosion has progressed on the inner wall of the pipe and rust is firmly fixed, the cleaning time can be greatly reduced as compared with the conventional ozone cleaning method. Since slime that needs to be sterilized and washed is peeled and removed mostly with acid, high-pressure water containing a bactericide is supplied in the post-process, and the slime is decomposed and removed. Due to the peeling effect, rust and slime in the pipe can be completely sterilized and removed in a short time.

  According to the present invention, by performing a method that has not been performed at all in this type of water supply pipe sterilization cleaning of peeling and removing rust with acid, there is no problem that red water does not stop as in the past, so extremely There are no problems such as requiring a long construction time or exchanging piping due to red water. In addition, even if acid cleaning is performed, considering that the long-time construction due to red water is eliminated, the average construction time is much shorter than before, so there is a great economic advantage.

  Next, an embodiment of the present invention will be described.

  The method of the present invention preferably comprises the following three steps.

(1) After flowing warm water into the water supply pipe and raising the temperature of the pipe, a strongly acidic (preferably pH 2 or lower) solution is flowed into the water supply pipe and left for a predetermined time.
(2) Supply high-pressure water containing a bactericide, discharge the acid, discharge the peeled red rust, and decompose and sterilize the slime.
(3) Rinse the water supply pipe with city water.

The effect of the peeling step using the strongly acidic solution (1) increases as the temperature increases. Although it is good to set it as 30 degreeC or more, since water supply piping is mainly a vinyl chloride piping, it is good to set it as a maximum to 60 degreeC. If warm water of 60 ° C. and an acid solution are poured into the water supply pipe and left for 1 hour, the average temperature can be maintained at 30 ° C. even in winter. Although the method of the present invention can be applied even at a temperature lower than 30 ° C., if the temperature is too low, the construction takes a long time, which is not practical.

  In order to see the contact time of the acid aqueous solution necessary for peeling and removing red rust in the water supply piping, in the beaker experiment, citric acid aqueous solution was used as the acid, and the citric acid temperature and pH were changed, and most of the red rust peeled off. Time (min) was measured. The results are shown in Table 1 below.

表１の結果から、クエン酸濃度が高いほど、また温度が高いほど接触時間は、少なく済むことがわかる。実際の施工に当っては、これを目安とすることができる。

From the results in Table 1, it can be seen that the higher the citric acid concentration and the higher the temperature, the shorter the contact time. This can be used as a guide for actual construction.

The step of flowing the acid solution in the step (1) is to install a solution mixer after the water meter, mix a high-concentration citric acid aqueous solution with city water, open one water tap and pass for a certain period of time. Water may be used, or an acid aqueous solution whose concentration is adjusted may be prepared in a tank, and a single water tap may be opened from the secondary side of the water meter with a pump to pass water. However, when it is confirmed that the acid aqueous solution has flowed out of the water tap, the water tap is opened and the supply of the acid aqueous solution is stopped at the same time so that the acid aqueous solution stays in the pipe and is held for a certain period of time. Is desirable from the viewpoint of reducing the consumption of the aqueous acid solution.

(1) Acid solutions that have a peeling effect in the process are strong acids, and may be sulfuric acid, nitric acid, etc., but considering that the user should not be worried even if the solution remains in the pipe, it is an organic acid, food Citric acid, lactic acid, adipic acid, succinic acid, glyconodelta lactone, gluconic acid, fumaric acid, DL-malic acid, tartaric acid, acetic acid and electrolyzed water approved as additives are preferred. In particular, citric acid and mixed water of electrolytic water and the above organic acid are preferable.
The step (2) promotes the decomposition and removal of slime that could not be removed in the step (1) and the discharge of the acid aqueous solution from the dead end portion of the pipe and the physical separation of the deposits to the outside of the pipe. In order to discharge rust humps, slime, etc. in a short time, if possible, turbulent high-pressure water is supplied to the piping.

  In order to realize turbulent flow reliably, although it depends on the pipe diameter, it is desirable that the flow rate is 1.5 m / sec or more, and the Reynolds number is 20,000 or more. For this purpose, a supply pressure of 0.2 Pa or more is necessary, and therefore, by supplying high-pressure water containing a bactericidal agent or by intermittently supplying a solution containing a bactericidal agent by opening and closing a valve, Turbulence can also be formed.

In the process of rinsing the inside of the piping by passing the city water in (3), remove the equipment to be cleaned, return to the state before cleaning, and pass the city water in the normal use state. In order to discharge the residual acid aqueous solution, it is desirable to pass water from each water tap for 5 minutes or more for safety. When city water contains a disinfectant, (2) and (3) can be performed in the same process.

  The following examples further illustrate the present invention.

Basic experiment A: Red rust peeling experiment A rusted iron pipe was immersed in 150 cc of the sample solution shown in Table 2 for 1 hour to observe the rust peeling state. The results are shown in Table 2 below.

上記Ｎｏ．１及び２は、１５分経過から剥離開始し、６０分で剥離完了した。

No. above. For 1 and 2, peeling started after 15 minutes, and peeling was completed in 60 minutes.

Example The apparatus shown in FIG. 2 was used to sterilize and clean the water supply piping of a detached house by the method of the present invention.
(Equipment used for testing)
As shown in FIG. 2, the on-off valve 2 is closed, and a solution containing citric acid and a bactericidal agent (hereinafter referred to as high-pressure sterilized water) feeder A and a water supply pipe 9 are connected to the secondary side of the water meter 3. 11 connected.

The citric acid and high-pressure sterilizing water supply device A is composed of a citric acid aqueous solution 15 that has been adjusted beforehand to pH 1 to 2, a pump 14, a gas hot water tower 12, and a citric acid three-way valve 13.
(Implementation of cleaning)
Step 1: Citric acid aqueous solution sealing step Close the on-off valve 2 and install a cleaning piping as shown in FIG. 2, and set the three-way valve 13 so that the citric acid aqueous solution 15 circulates. The citric acid aqueous solution of .1 was circulated through the gas hot water tower 12 until it reached 60 ° C. Then, the citric acid three-way valve 13 and the three-way valve 11 were operated to pass the citric acid aqueous solution 15 through the water supply pipe 9.

  The method of passing the citric acid aqueous solution is to open only one water tap 10, measure the pH of the citric acid aqueous solution coming out of the water tap 10, and when the pH becomes 2 or less, The same measurement was carried out with the other water taps closed and the other water taps opened, and each of the water taps was sequentially performed, and the citric acid aqueous solution was sealed in the water supply pipe 9 for about 60 minutes.

Process 2: Removal of rust and organic matter (slime) After sealing the citric acid aqueous solution, operate the three-way valve with 5 ppm hypochlorous water from the supply tank of citric acid and high-pressure sterilized water supply A, and pump 14 Was passed through the water supply pipe 9 as high-pressure sterilized water. At this time, the water tap 10 was opened at only one place, and the other water taps were closed. The same high-pressure sterilized water was supplied to the remaining water taps. In addition, when city water contains a disinfectant, the three-way valve 11 may be set on the tap water side, and the on-off valve 2 may be opened to allow tap water to pass through so that turbulent flow occurs.

Step 3: Rinsing Step Next, set the three-way valve 11 so that tap water passes through the water supply pipe 9, open the on-off valve 2, pass tap water, open all the taps, and supply tap water. Water was passed for 5 minutes, and it was confirmed that red water did not come out and that the tap water had a pH of 6.8 or more, and the rinsing step was completed.

  The present example is for a detached house that is 10 years old and that has been cleaned with ozone water about a year ago. In step 2, a large amount of red water was confirmed to flow out of the water tap, and in step 3, there was no red water. Cleaning with ozone water was not very effective in removing rust, but the cleaning method of the present invention was effective in removing rust. It was confirmed to be effective.

  The cleaning work time in a standard detached house is 60 minutes for the rust removal process (process 1), 25 minutes for the rust removal process using high-pressure sterilized water (process 2), and 5 minutes for the rinse process (process 3). The total installation time and the removal time of 30 minutes for the other cleaning pipelines are approximately 120 minutes, which is not much different from the existing ozone water cleaning and provides a great economic advantage.

  So-called rust humps, which are a mixture of rust and rust and organic matter (slime), are peeled off from the inner wall of the pipe by washing with acid (citric acid), but only organic matter is attached to the PVC lining pipe and poly pipe, etc. In citric acid (acid aqueous solution), organic substances are not decomposed and cannot be removed.

  In this way, organic substances (slime) cannot be removed by washing with acid (citric acid), but by supplying high-pressure water containing a bactericidal agent in the subsequent process, the slime is decomposed and removed, so that it is physically high-pressure water. In addition, the slime can be easily peeled off from the inner wall, and as a result, the rust and organic matter in the pipe can be almost completely removed and sterilized and washed.

  The same effect can be obtained by simply running tap water for a long time, but by supplying high-pressure water containing a disinfectant preferably turbulently, it can be immediately provided to the essentials of life in a short time. .

  According to the present invention, there is no problem that red water does not stop as in the prior art, and ozone cleaning and an air hammer can be dispensed with.

It is a block diagram which shows the washing | cleaning method of the conventional water supply piping. It is a block diagram which shows the washing | cleaning method of the water supply piping of this invention.

Explanation of symbols

2 ......... Opening / closing valve 3 ......... Water meter 5 ......... Compressed air input device 11 ......... 3-way valve 12 ...... Gas hot water tower 15 ......... Citric acid aqueous solution A ......... Citric acid and sterilization Solution feeder containing chemicals

Claims (6)

In the method of sterilizing and cleaning a water supply pipe having red rust attached to the inner wall of the pipe, the method includes bringing the acid aqueous solution into contact with the inner wall of the pipe and peeling the rust, and supplying high-pressure water containing a bactericide. A method for sterilizing and cleaning a water supply pipe. The sterilization cleaning method according to claim 1, wherein the high-pressure water is turbulently supplied. The sterilization cleaning method according to claim 1 or 2, wherein the step of peeling the rust is performed at 30 to 60 ° C. The sterilizing and cleaning method according to any one of claims 1 to 3, wherein the step of bringing the acid aqueous solution into contact with the inner wall of the pipe to release rust is performed at a pH of 2 or less. The acid is one or more selected from the group consisting of citric acid, lactic acid, adipic acid, succinic acid, glyconodelta lactone, gluconic acid, fumaric acid, DL-malic acid, tartaric acid, acetic acid and electrolyzed water. The sterilization washing method according to any one of claims 1 to 4. The sterilizing and cleaning method according to claim 5, wherein the acid is citric acid.

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