Existing pipe rehabilitating method

Abstract

To achieve construction of existing piping for a hot water supply facility in consideration of heat resistance and followability to thermal contraction according to characteristics of paint used for the piping and lining.SOLUTION: The method includes a step of drying the inside of the existing hot water supply pipe 2 after cleaning the inside of the existing hot water supply pipe 2, a step of polishing the inside of the existing hot water supply pipe 2 by injecting an abrasive with dry compressed air while advancing the inside of the existing hot water supply pipe 2 from both ends to a target position, and a step of coating the inside of the existing hot water supply pipe 2 by injecting a paint having a predetermined viscosity with compressed air while advancing the inside of the existing hot water supply pipe 2 from both ends to the target position. As the lining material to be applied to the inside of the existing hot water supply piping 2 in this construction method, a material obtained by blending a main material containing an epoxy resin as a main component and a curing agent containing a modified alicyclic polyamine as a main component at a weight ratio of 100:50 is used.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a construction method for rehabilitating existing hot water supply piping laid within a building. [Background technology]

[0002] Conventionally, known lining methods for rehabilitating existing pipes such as general water supply pipes include a method of grinding and cleaning the inner surface of the pipe and then applying a lining using paint.For example, one lining method involves grinding and cleaning the inside of an existing pipe that is installed in a building and has multiple branch pipes branching off from it, dividing the existing pipe into painting sections from one end to the other and for each branch pipe, supplying a solvent-free two-component epoxy resin paint from the end of the pipe to each section, and applying a primary coat by spraying and a secondary coat by pushing and spreading using a sliding member to form a coating film of a predetermined thickness inside the pipe (see Patent Document 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-142707 Summary of the Invention [Problem to be solved by the invention]

[0004] However, even among existing piping, those for hot water supply equipment differ from those for general water supply and drainage pipes in that they are made of heat-resistant materials such as copper pipes and have smaller pipe diameters due to factors such as heat retention, thermal efficiency, and water pressure. In particular, lining methods for hot water supply equipment piping require the paint used for the lining to be heat-resistant and able to follow the thermal contraction of copper pipes, which requires different characteristics and construction methods than those for general water supply and drainage pipes. However, in the past, lining methods for general water supply and drainage pipes have been used in the vast majority of cases, and there is a need for the development of construction methods suitable for hot water supply piping.

[0005] Therefore, this invention has been made to solve the above problems, and aims to provide a method for realizing construction of existing piping for hot water supply equipment, taking into consideration heat resistance and adaptability to thermal shrinkage, depending on the properties of the paint used for the piping and lining. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides a lining material that is applied to the inside of existing hot water supply pipes laid within a building in a construction method for rehabilitating the existing pipes, and is characterized in that the main material, whose main component is epoxy resin, and the curing agent, whose main component is modified alicyclic polyamine, are blended in a weight ratio of 100:50 to give a blend structure viscosity ratio of 6, and the usable time is 70% of the maximum heat generation time.

[0007] In the lining material of the invention, it is preferable that the viscosity of the main material is 70,000 mPa·s in an environment of 23°C, the viscosity of the curing agent is 65,000 mPa·s in an environment of 23°C, and the viscosity of the main material and curing agent when combined is 60,000 mPa·s in an environment of 23°C. Furthermore, it is preferable that the lining material of the invention has a pot life of 90 minutes and a coating curing time of 10 hours, and furthermore, it is preferable that the tensile strength after curing is 30 to 35 mPa and the elongation at maximum load after curing is 5%.

[0008] Another invention is a method for rehabilitating existing hot water supply piping laid within a building, the method comprising the steps of cleaning the inside of the existing piping and then drying it, polishing the existing piping by spraying an abrasive with dry compressed air while moving from both ends of the existing piping toward the target position, and painting the existing piping by spraying paint having a predetermined viscosity with compressed air while moving from both ends of the existing piping toward the target position.

[0009] In the above invention, an inspection process is carried out prior to the drying process to inspect the condition of the inner surface of the existing piping, and depending on the inspection results of the inspection process, sterilization cleaning using ozone is carried out as cleaning in the drying process, and it is preferable to omit the polishing process.

[0010] In the above invention, it is preferable that the wind speed of the dry compressed air used to spray the abrasive in the polishing step is 100 m / s, and the wind speed of the compressed air used to spray the paint in the painting step is 60 m / s. Also, in the above invention, it is preferable that the specific gravity of the paint in the painting step is 1.25, and the paint is applied so that the minimum film thickness of the paint is 300 μm or more.

[0011] Furthermore, in the above invention, it is preferable that after the painting step, a hardening and curing step is further included in which the temperature is increased stepwise from 40°C every predetermined time for 45 minutes or more, and the temperature is preferably increased by 10°C every 15 minutes in this hardening and curing step.

[0012] The lining material of the present invention can be used as a coating material in the method for rehabilitating an existing pipe, which is the above-mentioned invention. [Effects of the Invention]

[0013] In this invention, while moving through the existing pipe from both ends to the target position, an abrasive is sprayed with dry compressed air to polish the pipe, and paint is sprayed with compressed air. In this case, the air velocity of the dry compressed air spraying the abrasive is set to 100 m / s, and the air velocity of the compressed air spraying the paint is set to 60 m / s, so that polishing and painting can be performed at a pressure appropriate for the diameter of the hot water supply pipe and the heat resistance and followability (viscosity) of the paint. In addition, by curing the paint after the painting process, the paint can be properly hardened in stages, allowing it to demonstrate its strength as a lining material.

[0014] Furthermore, by setting the specific gravity of the paint to 1.25 and applying the paint so that the minimum film thickness is 300 μm or more, it is possible to apply an appropriate lining to small diameter, heat-shrinkable hot water pipes.As a result, for existing pipes for hot water supply equipment, construction that takes into account heat resistance and adaptability to thermal shrinkage can be achieved according to the properties of the paint used for the pipes and lining.

[0015] Furthermore, in the present invention, if the inspection results of the existing piping show no corrosion or the type of corrosion is moundless pitting, it is preferable to perform sterilization cleaning using ozone as the cleaning in the drying process and omit the polishing process. This allows the oxidizing power of ozone to decompose and sterilize slime stains, forming an oxide film inside the cold water and hot water pipes and preventing the adhesion of slime and stains. In this case, since the polishing process (S104) is not performed, the existing piping can be maintained in a reinforced state by the oxide film and verdigris. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is an explanatory diagram showing a schematic view of the state of water supply pipes and hot water supply pipes in a detached house to which the rehabilitation method according to the embodiment can be applied. [Figure 2] FIG. 1 is a flowchart showing the procedure of a rehabilitation method according to an embodiment. [Figure 3] FIG. 2 is an explanatory diagram showing a polishing step in the rehabilitation method according to the embodiment. [Figure 4] FIG. 2 is an explanatory diagram showing a polishing step in the rehabilitation method according to the embodiment. [Figure 5] FIG. 2 is an explanatory diagram showing a lining process in the rehabilitation method according to the embodiment. [Figure 6] FIG. 2 is an explanatory diagram showing a lining process in the rehabilitation method according to the embodiment. [Figure 7] 1 is a cross-sectional view showing each step of a hot water supply pipe that is the subject of a rehabilitation method according to an embodiment. BEST MODE FOR CARRYING OUT THE INVENTION

[0017] A rehabilitation method according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic diagram of existing piping, such as a water supply pipe and a hot water supply pipe, in a detached house 1. In the figure, a water supply pipe 11 and a hot water supply pipe 12 are installed under the floor of the detached house 1 from an installation position E of a water heater 3 in the detached house 1, and are then routed to each room in the building, such as a kitchen A, a bathroom B, and a washroom C. The following embodiments are merely examples of devices embodying the technical concept of the present invention, and the technical concept of the present invention does not limit the materials, shapes, structures, arrangements, etc. of each component to those described below. Various modifications can be made to the technical concept of the present invention within the scope of the claims.

[0018] As shown in Figure 1, the water supply pipe 11 and the hot water supply pipe 12 are branched via a water supply branch tee 100 and a hot water supply branch tee 200, respectively, and each pipe is raised from under the floor into the room via an elbow joint. At the branch tee 100 and 200, multiple branch pipes are branched and connected, and a discharge member such as a faucet is generally attached to the free end side (hereinafter referred to as the "terminal side") of each branch pipe.

[0019] Here, we will explain an example of carrying out a rehabilitation method on an existing hot water supply pipe 2. This existing hot water supply pipe 2 is a copper pipe, and a vertical pipe 203 is connected via an elbow joint 202 to a horizontal pipe 201 branched from a hot water supply branch tee 200.

[0020] A single-lever mixer tap 4 is connected to the end of the vertical pipe 203, and this single-lever mixer tap 4 is connected to the vertical pipe 203 for hot water supply and the vertical pipe 10c of the water supply piping 10.By moving the lever left and right, the ratio of the hot and cold water discharge volumes can be adjusted to change the water temperature, and by moving it up and down, the water volume can be adjusted and the water can be turned on and off.

[0021] (lining material) The lining material used in this embodiment is formulated to be easy to use in a construction method for rehabilitating existing hot water supply pipes. This lining material is a 100:50 weight ratio blend of a main material whose main component is epoxy resin and a curing agent whose main component is modified alicyclic polyamine, with a blend structure viscosity ratio of 6 and a pot life of 70% of the maximum heat generation time.

[0022] In this embodiment, the viscosity of the main material at 23°C is 70,000 mPa·s, the viscosity of the curing agent at 23°C is 65,000 mPa·s, and the viscosity of the main material and curing agent when combined is adjusted to 60,000 mPa·s at 23°C. This lining material is mixed, for example, using a rotary can-type vacuum degassing mixer, and is adjusted to have a pot life of 90 minutes and a coating curing time of 10 hours. Furthermore, it is preferable that the tensile strength after curing is 30 to 35 mPa, and the elongation at maximum load after curing is 5%.

[0023] Table 1 shows a list of the properties of specific lining materials for water supply, and Table 2 shows a list of the properties of lining materials for hot water supply. [Table 1] [Table 2]

[0024] (Rehabilitation method procedure) The rehabilitation method of the present invention can be applied to the existing pipes of the detached house 1 described above. Figures 2 and 7 show the procedure for the rehabilitation method according to this embodiment and a cross section of the hot water supply pipe to which this work is applied. Note that the processing procedure described below is merely an example, and each process may be modified as much as possible. Furthermore, steps in the processing procedure described below can be omitted, replaced, or added as appropriate depending on the embodiment.

[0025] The rehabilitation method according to this embodiment is a method for rehabilitating existing hot water supply piping (here, hot water supply pipe 20) laid within a detached house 1, and as shown in FIG. 2, first, an investigation and diagnosis (inspection process) of the existing piping is carried out (S101).

[0026] In this inspection process, the condition of the inner surface of the existing hot water supply pipe 20 is inspected, and the corrosion state (presence and type of corrosion) of the inner surface of the existing pipe is primarily determined (S102). The corrosion state of the inner surface of the existing pipe is so-called pitting corrosion (a type of localized corrosion that occurs in copper pipes, etc.), which can be broadly classified into type 1, type 2, and moundless type. Type 1 pitting corrosion forms a wide, cone-shaped opening, and the main corrosion product is a patina of basic copper carbonate (CuCO3·Cu(OH)2) that covers the top of the pit. Type 2 pitting corrosion forms a narrow, octopus-pot-shaped opening, and the main corrosion product is a patina of basic copper sulfate (CuSO4·3Cu(OH)2) that covers the top of the pit. Moundless pitting corrosion forms pinhole-like holes, and the main corrosion product is a glassy patina around the pit opening.

[0027] In step S102, if the type of corrosion is the above-mentioned type 1 or type 2 pitting corrosion ("type 1 / type 2 pitting corrosion" in S102), the inside of the existing pipe is cleaned and dried (drying step) (S103). At this point, for example, as shown in FIG. 7(a), the inner surface of hot water supply pipe 20 is covered with dirt such as rust and scale. The cleaning method involves removing dirt such as rust and scale from the entire inside of hot water supply pipe 12 using an appropriate abrasive cleaning means as a pre-lining step, and then drying the inside by blowing air or the like to make it clean.

[0028] Then, the existing pipe is polished (polishing step) (S104). Specifically, as shown in Fig. 7(b), dry compressed air is used to move abrasive material 54a within hot water supply pipe 20, polishing the inner surface of the pipe. In this embodiment, the wind speed of the dry compressed air spraying abrasive material 54a is set to 100 m / s.

[0029] Specifically, in this polishing process, all faucets on existing hot water supply pipes 20a-d (see FIG. 1) are removed, and air supply hoses 56 are connected to their respective ends 4a-4d. The air supply hoses 56 are connected to air outlets 50a-50d of an air distributor 50. An air compressor 52 is connected to supply port 50e of the air distributor 50 via an air dehumidifier 53. Compressed air delivered from the air compressor 52 is dried by the air dehumidifier 53 and then distributed to each air supply hose 56 by the air distributor 50. Each air outlet 50a-50d of the air distributor 50 can be opened and closed with an on-off valve, allowing selective opening and closing of the on-off valve to control the air supply to any existing pipe or other equipment. During polishing, abrasive material 54a is introduced into the end of each existing hot water supply pipe, and dry compressed air is sprayed from the air distributor 50 to move the abrasive material 54a from one end to the other.

[0030] In the example shown in Figure 3, an abrasive dispenser 54 is connected midway to an air supply hose 56 connected to the end 4a of an existing hot water supply pipe 20a, allowing abrasives 54a to be blown into the end 4a together with compressed air. The abrasives 54a blown into the end 4a of the existing hot water supply pipe 20a are pushed by the compressed air through the existing hot water supply pipe 20a toward the water heater 3, and are collected along with the ground-up rust and other debris by a dust collector 51 via a recovery hose 58 connected to the end 4e on the water heater 3 side. At this time, the valves of the air outlets 50b-d of the air distributor 50 connected to the other existing hot water supply pipes 20b-20d are closed to prevent air leakage. As a result, the air blown into the end 4a is transported to the end 4e on the water heater side, where resistance is low, and collected by the dust collector 51.

[0031] Thereafter, the air supply hose 56 connecting the abrasive dispenser is reconnected to the hot water supply pipes 20b, 20c, etc. in order, and the air supply ports to be opened are changed to 50b, 50c, etc., thereby polishing all the existing hot water supply pipes.

[0032] In this embodiment, polishing with the abrasive 54a is performed twice, from both ends of each existing hot water pipe, by changing the supply side of the abrasive 54a. That is, for the second polishing, the abrasive 54a is supplied from the water heater side, as shown in FIG. 4 . Specifically, an abrasive supply device 54 is connected to the middle of an air supply hose 56 connected to the water heater-side end 4e of the branch tee 200, and the abrasive 54a is blown into the water heater-side end 4e together with compressed air. The abrasive 54a blown into the water heater-side end 4e of the branch tee 200 is pushed by the compressed air through the existing hot water supply pipe 20a toward the end 4a, and is collected into the dust collector 51 along with the polished rust, etc., via the collection hose 58 connected to the end 4a. At this time, as described above, the valves of the air supply ports 50b-d of the air distributor 50 connected to the other existing hot water supply pipes 20b-20d are closed to prevent air leakage. As a result, the air blown into the hot water heater side end 4e moves to the end 4a where resistance is low, and the dust is collected by the dust collector 51.

[0033] Thereafter, the air supply hose 56 connecting the dust collector 51 is successively reconnected to the hot water supply pipes 20b, 20c, etc., and the air supply ports to be opened are changed to 50b, 50c, etc., thereby polishing all the existing hot water supply pipes.

[0034] In this type of polishing, No. 3 sand is used as the abrasive 54a, and the air velocity is set to 100 m / sec to ensure that the patina that has formed on the base inside the pipe is completely removed. When polishing an existing hot water pipe, refer to the table below and polish until the metallic luster of the copper that forms the base of the pipe becomes visible, and after polishing, dry thoroughly with an air blower. [Table 3]

[0035] On the other hand, if there is no corrosion or if the type of corrosion is the moundless pitting corrosion described above ("No corrosion, moundless" in S102), sterilization cleaning using ozone is performed (S105) as cleaning in the drying step (S103), and the polishing step (S104) is omitted.

[0036] Ozone disinfection cleaning utilizes ozone water, which oxidizes and decomposes iron hydroxide and organic matter, and impulse air, which sends compressed air in a pulsed manner to remove and remove the dirt and slime that has formed inside the pipes. The ozone contained in ozone water is generated by electrically processing oxygen in the air. It has bactericidal and oxidizing properties, but decomposes quickly, leaving no residue behind. This ozone disinfection cleaning process uses the oxidizing power of ozone to decompose and disinfect slime, forming an oxide film inside the water supply and hot water pipes, preventing the adhesion of slime and dirt. Because the oxide film and verdigris reinforce the interior of the existing pipes, the polishing process (S104) is not performed here. After this ozone disinfection cleaning, the process is dried and then moved on to the lining process (painting process).

[0037] Then, after the polishing step (S104) or ozone sterilization and cleaning (S105), lining with paint (painting step) is performed (S106). Specifically, as shown in FIG. 7(c), paint 55a having a predetermined viscosity is sprayed by compressed air while traveling through the existing pipe from both ends to the target position. In this embodiment, the compressed air spraying the paint 55a has a wind speed of 60 m / s, the specific gravity of the paint is 1.25, and the paint 55a is applied so that the minimum film thickness is 300 μm or more. The lining material is mixed, for example, using a can-rotating vacuum degassing mixer or the like, just before lining construction.

[0038] The defoaming treatment before the lining application includes agitation using a mechanical mixer or ultrasonic waves, defoaming and degassing by reducing the pressure using a pump, etc., as well as using an antifoaming agent or defoamer to prevent bubbles from forming in the paint or to promote the breaking down of bubbles that have formed. In this embodiment, when the base material and the admixture are mixed using a can-rotating vacuum defoaming mixer to produce the lining material, mixing and defoaming are performed in a short time by simultaneously performing vacuum (decompression) and motion (mixing). The can-rotating vacuum defoaming mixer mixes the base material and the admixture with a mixing motion while reducing the pressure inside a vacuum tank filled with the base material and the admixture, causing the can bottom material to rise and bubbles to swell on the surface due to the vacuum force, and then destroying the bubbles with the circular mixing motion.

[0039] In this embodiment, all piping is coated alternately from both directions. For example, in the case of the piping shown in FIG. 1, coating is first performed from the end 4a of kitchen A to the end 4b of bathroom B via the hot water supply branch tee 200, as shown in FIG. 5. The length of the piping from the end 4a of kitchen A to the midpoint of the end 4b of bathroom B in the vertical pipe and the planned coating thickness are calculated in advance, and an appropriate amount of paint 55a is poured from both the ends of the hot water supply branch tee 200 and the vertical pipe 203. Then, compressed air is sprayed to spread the paint 55a while the spray nozzle 5 is introduced, and the paint 55a is spread by the required supply pressure to form a coating. After coating from the kitchen A side is completed in this manner, coating is performed from the end 4b of bathroom B to the other end (end 4e of the tee 200) as shown in FIG. 6. In this coating, the paint 55a is also spread by the required supply pressure to form a coating.

[0040] To describe this lining process in more detail, for example, as shown in Figures 5 and 6, an air supply hose 56 is connected to each of the ends 4a to 4d of all of the existing hot water pipes 20a to 20d. This air supply hose 56 is connected to each of the air supply ports 50a to 50d of an air distributor 50. An air compressor 52 is connected to a supply port 50e of this air distributor 50 via an air dehumidifier 53, and compressed air sent out from the air compressor 52 is dried by the air dehumidifier 53 and then distributed to each of the air supply hoses 56 by the air distributor 50. Each of the air supply ports 50a to 50d of the air distributor 50 can be opened and closed by an opening and closing valve, and by selectively opening and closing the opening and closing valve, it is possible to control the air supply to any existing pipe or other equipment. During lining, ends 4a to 4d of each existing hot water supply pipe 20a to d are selected in sequence, an air supply hose 56 is connected, and paint is poured in. At the same time, ends 4a to 4e of each existing hot water supply pipe 20a to d or tee 200 are selected in sequence, a collection container 57 is connected, and dry compressed air is sprayed from the air distributor 50 to spread the paint from one end to the other end.

[0041] In the example shown in Figure 5, a container 55 is used to inject lining material into the end 4a of the existing hot water supply pipe 20a in kitchen A. The lining material injected into the end 4a of this existing hot water supply pipe 20a is pushed by compressed air and moves inside the hot water supply pipe 20 while being pushed and expanded toward the water heater 3, and is then discharged and collected into a collection container 57 connected to the end 4e on the water heater 3 side. At this time, the valves of the air outlets 50b-d of the air distributor 50 connected to the other existing hot water supply pipes 20b-20d are closed to prevent air leakage. As a result, the air blown into the end 4a moves to the end 4e on the water heater side, which has lower resistance, and is collected by the collection container 57.

[0042] Thereafter, the existing hot water supply pipes into which the lining material is injected are sequentially changed to hot water supply pipes 20b, 20c, etc., and the air supply ports to be opened are changed to 50b, 50c, etc., until all the existing hot water supply pipes are lined.

[0043] As described above, the lining according to this embodiment is performed on each existing hot water pipe by changing the lining material injection side. That is, for each lining, the lining material is injected from the water heater side, as shown in FIG. 6 . Specifically, a collection container 57 is connected to a collection hose 58 connected to the water heater-side end 4e of the branch tee 200, and the lining material is blown into the end 4c together with compressed air. The lining material blown into the end 4b is pushed by the compressed air through the existing hot water supply pipe 20b toward the end 4e and collected in the collection container 57 via the collection hose 58 connected to the end 4e. At this time, as described above, the valves of the air outlets 50b-d of the air distributor 50 connected to the other existing hot water supply pipes 20b-20d are closed to prevent air leakage. As a result, the air blown into the end 4e moves to the water heater-side end 4a, where resistance is low, and the lining material is collected in the collection container 57.

[0044] Thereafter, the existing hot water supply pipes into which the lining material is injected are sequentially changed to hot water supply pipes 20b, 20c, etc., and the air supply ports to be opened are sequentially changed to 50b, 50c, etc., until all the existing hot water supply pipes are lined.

[0045] In addition, for these hot water supply linings, the viscosity of the paint for hot water supply is half that of the paint for water supply, so the air flow rate is lower than the air flow rate of the water supply pipe, and is set to the equivalent of 60m / sec as shown in the table below. [Table 4]

[0046] After this lining, the lining condition is inspected, and the curing equipment is removed (S107 and S108). Here, after the painting process in step S104 described above, hardening and curing is performed for at least 45 minutes by passing hot water through the pipe, gradually increasing the temperature from 40°C at predetermined intervals. In this embodiment, this hardening and curing process involves passing hot water through the pipe, increasing the temperature by 10°C every 15 to 20 minutes from 40°C to 60°C. The maximum temperature of the hot water passed through during this hardening and curing process can be determined based on the performance of the water heater. Generally, 60°C is sufficient. However, if the water heater's performance is, for example, 70°C, hot water is passed through at 70°C for an additional 15 minutes. At this time, it is preferable to seal the pipe end after lining with masking tape and leave it to harden and cure for a predetermined period of time (e.g., overnight). Depending on the situation, a portable water heater may be connected and hardening and curing may be performed at 70°C, as shown in the table below. [Table 5]

[0047] After the restoration work, water is passed through the pipe (S109). Specifically, after the hot water curing, the pipe is cooled to room temperature, and it is confirmed that the hardness of the coating film is H hardness or higher. If the hardness passes, the pipe is restored.

[0048] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be created by appropriately combining the components disclosed in the above-described embodiments. For example, some components may be omitted from all the components shown in the embodiments.

[0049] (Actions and Effects) As explained above, in this embodiment, the target position is moved through the existing pipe from both ends, while the abrasive 54a is sprayed with dry compressed air to polish the pipe, and the paint is sprayed with compressed air to paint the pipe. In this case, the wind speed of the dry compressed air spraying the abrasive is set to 100 m / s, and the wind speed of the compressed air spraying the paint is set to 60 m / s, so that polishing and painting can be performed at pressures appropriate for the diameter of the hot water supply pipe and the heat resistance and followability (viscosity) of the paint.

[0050] Furthermore, by setting the specific gravity of the paint to 1.25 and applying the paint so that the minimum film thickness is 300 μm or more, it is possible to apply an appropriate lining to small diameter, heat-shrinkable hot water pipes.As a result, for existing pipes for hot water supply equipment, construction that takes into account heat resistance and adaptability to thermal shrinkage can be achieved according to the properties of the paint used for the pipes and lining.

[0051] In particular, in this embodiment, if the inspection results of the existing piping show no corrosion or the type of corrosion is the moundless pitting corrosion described above, sterilization cleaning using ozone is performed as the cleaning in the drying process, and the polishing process is omitted. This allows the oxidizing power of ozone to break down and sterilize slime stains, forming an oxide film inside the cold water and hot water pipes and preventing the adhesion of slime and dirt. In this case, because the polishing process (S104) is not performed, the existing piping O can be maintained in a reinforced state with the oxide film and verdigris.

[0052] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be created by appropriately combining the components disclosed in the above-described embodiments. For example, some components may be omitted from all the components shown in the embodiments. [Explanation of symbols]

[0053] A…Kitchen B…Bathroom C...washroom D...External mounting position E...Water heater installation location 1... Detached house 2...Existing hot water piping 2a…Vertical pipe 3...Water heater 4...Single-lever mixer tap 4a~4d…Hot water pipe end 4e...Hot water heater end 5...Injection nozzle 10...Water supply piping 10c…Vertical pipe 11…Water supply pipe 12...Hot water pipe 20...Hot water pipe 20a~d...Existing hot water pipes 50...Air distributor 50a~50d...Air outlet 50e…supply port 51...Dust collector 52...Air compressor 53...Air dehumidifier 54…Abrasive material feeding machine 54a…Abrasive material 55...Container 56...Air supply hose 57...Collection container 58...Recovery hose 100,200...branch cheese 201…Horizontal pipe 202...Elbow joint 203…Vertical pipe

Claims

1. A construction method for rehabilitating existing hot water supply piping installed in a building, a drying step of cleaning the inside of the existing pipe and then drying it; a polishing step of spraying an abrasive with dry compressed air while moving the abrasive through the existing pipe from both ends to a target position; a coating process in which paint having a predetermined viscosity is sprayed by compressed air while moving the paint to a target position inside the existing piping from both ends; Including, As the paint having the predetermined viscosity, a lining material is used that is made by blending a main material containing an epoxy resin as a main component and a curing agent containing a modified alicyclic polyamine as a main component, The lining material is formulated so that the end of its usable life is when it reaches 70% of the maximum heat generation time, and then the coating process is carried out. A method for rehabilitating existing piping.

2. an inspection step of inspecting the state of the inner surface of the existing pipe prior to the drying step; The method for rehabilitating existing piping as described in claim 1, characterized in that, depending on the inspection results of the inspection process, sterilization cleaning using ozone is performed as cleaning in the drying process, and the polishing process is omitted.

3. In the polishing step, the wind speed of the dry compressed air for spraying the abrasive is 100 m / s, In the coating process, the compressed air used to spray the paint has a wind speed of 60 m / s.

2. The method for rehabilitating an existing pipe according to claim 1.

4. 2. The method for rehabilitating an existing pipe according to claim 1, wherein in the coating step, the specific gravity of the paint is set to 1.25 and the paint is applied so that the minimum film thickness of the paint is 300 μm or more.

5. 2. The method for rehabilitating existing piping as described in claim 1, further comprising, after the painting step, a step of passing hot water through the pipe for 45 minutes or more, gradually increasing the temperature from 40°C at predetermined time intervals, to harden and cure the pipe.

6. 6. The method for rehabilitating an existing pipe according to claim 5, wherein the temperature is increased by 10° C. every 15 minutes in the hardening and curing step.

7. The method for rehabilitating existing pipes according to claim 1, characterized in that a main material whose main component is epoxy resin and a curing agent whose main component is modified alicyclic polyamine are blended in a weight ratio of 100:50, the blending structural viscosity ratio is set to 6, and the usable time is adjusted to 70% of the maximum heat generation time.

8. The viscosity of the base material in an environment of 23°C is 70,000 mPa s, and the viscosity of the curing agent in an environment of 23°C is 65,000 mPa s, 2. The method for rehabilitating an existing pipe according to claim 1, wherein the viscosity of the main material and the hardener when mixed together is 60,000 mPa·s in an environment of 23°C.

9. 2. The method for rehabilitating an existing pipe according to claim 1, wherein the pot life is 90 minutes and the coating hardening time is 10 hours.

10. 2. The method for rehabilitating an existing pipe according to claim 1, wherein the tensile strength after hardening is 30 to 35 mPa, and the elongation rate at maximum load after hardening is 5%.

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