Methods and systems for cleaning wastewater pipes in buildings.

Abstract

To address the increasing amount of sludge adhering to the inside of wastewater pipes, this system prevents the accumulation of attached sludge. [Solution] The wastewater pipe cleaning system comprises an ultrafine bubble generating unit 11 that imparts ultrafine bubbles with a diameter of less than 1 μm to the water passing through it; a water storage tank 21 that stores the water flowing out from the ultrafine bubble generating unit 11; a high-pressure unit 31 that receives and pressurizes the water flowing out from the water storage tank 21; a hot water unit 41 that receives and heats the high-pressure water flowing out from the high-pressure unit 31; a hose 44 made of a flexible material through which high-pressure hot water flows, having a base end connected to the hot water unit 41 and a tip end that passes through the wastewater pipe; and a tip nozzle 51 attached to the tip of the hose 44 that sprays high-pressure hot water containing ultrafine bubbles.

Description

Technical Field

[0001] The present invention relates to the cleaning of miscellaneous drain pipes.

Background Art

[0002] The miscellaneous drain pipes in apartment buildings are laid so as to extend from the exclusive parts of the residences to the shared parts that are not residences, and are connected to the sewer pipes outside the apartment buildings. Generally, the miscellaneous drain pipes in the exclusive parts are horizontal pipes that are connected to the sources of miscellaneous drainage such as bathtubs, kitchens, and washing machine pans and extend with a gradient, and it can be said that the flow time of the miscellaneous drainage is relatively short. In addition, the miscellaneous drain pipes in the shared parts are composed of a vertical pipe that is often connected to the downstream end of the miscellaneous drain pipe in the exclusive part and extends vertically, a horizontal main pipe that is connected to the downstream end thereof, and an in-site buried pipe that is connected to the downstream end thereof, and it can be said that the flow time of the miscellaneous drainage is relatively long.

[0003] Miscellaneous drainage includes washing water, bath water, face washing, and kitchen drainage, and contains various solid substances such as scale, soap scum, oil and fat, protein, hair, thread waste, and dust (also referred to as sludge or scale). Particularly in the path of the miscellaneous drain pipe into which kitchen drainage containing a large amount of oil and fat flows, such sludge gradually adheres to the inner wall surface of the miscellaneous drain pipe over time, and the problem that the flow cross-sectional area of the miscellaneous drain pipe becomes small is remarkable.

[0004] Therefore, it is common practice to carry out cleaning of the miscellaneous drain pipes to remove the sludge adhering to the inner wall surface of the miscellaneous drain pipes about once a year. As the cleaning of the miscellaneous drain pipes, for example, those described in JP-A-06-136817 (Patent Document 1) and JP-A-04-011978 (Patent Document 2) are known. A general miscellaneous drain pipe cleaning system includes a high-pressure unit supplied with normal temperature water (generally 5 to 25°C) from the water supply pipe, a hose made of a flexible material connected to the high-pressure unit, and a tip nozzle attached to the tip of the hose. An operator passes the hose through the miscellaneous drain pipe and injects high-pressure water while moving the tip nozzle along the miscellaneous drain pipe to remove the adhering sludge from the inner wall surface of the miscellaneous drain pipe.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Application Publication No. 06-136817 [Patent Document 2] Japanese Patent Application Publication No. 04-011978 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Conventional drainpipe cleaning methods often resulted in some attached sludge being left behind. This leftover sludge continued to adhere until the next drainpipe cleaning, preventing the drainpipe from achieving its intended flow cross-sectional area. Furthermore, new sludge continued to adhere to the old, leftover sludge.

[0007] Furthermore, in recent years, due to factors such as working from home during the COVID-19 pandemic, changes in lifestyles leading to changes in the rate of people working from home, a decrease in total wastewater volume due to the spread of water-saving appliances (dishwashers, washing machines, showerheads, etc.), and the widespread use of various toiletries containing gelling agents, solidification accelerators, and other chemicals such as mouthwash, sludge is more likely to adhere to the inner walls of wastewater pipes.

[0008] Furthermore, with the increasing height of apartment buildings, the length of shared wastewater pipes that are installed vertically is increasing, and the amount of time wastewater flows through them is also tending to increase, making it easier for sludge to adhere to the inner walls of these wastewater pipes.

[0009] In such cases, if conventional drainpipe cleaning is performed, a problem arises where sludge that has peeled off the inner wall of the drainpipe can clog the downstream side of the drainpipe, creating a risk of blockage.

[0010] In view of the above circumstances, the present invention aims to provide a wastewater pipe cleaning technology that can remove all attached sludge without leaving any behind, and that prevents sludge that has peeled off the inner wall surface of the wastewater pipe from clogging the downstream side of the wastewater pipe. [Means for solving the problem]

[0011] For this purpose, the wastewater pipe cleaning method according to the present invention involves passing a hose equipped with a nozzle at its tip into the wastewater pipe, supplying ultrafine bubble high-pressure hot water containing 7 to 100 million ultrafine bubbles with a diameter of less than 1 μm per 1 mL, with a water temperature of 30°C or higher and a water pressure of 2.0 MPa or higher, to the base end of the hose as it passes through the nozzle, and spraying the ultrafine bubble high-pressure hot water from the nozzle while moving the nozzle in the longitudinal direction of the wastewater pipe to remove sludge adhering to the inner wall surface of the wastewater pipe.

[0012] According to this invention, the surfactant action of ultrafine bubbles allows them to exhibit hydrophobic adsorption properties, adsorbing oil and protein from attached sludge. Furthermore, the negative charge on the surface of the ultrafine bubbles contributes to their adsorption properties. From a microscopic perspective, the minute ultrafine bubbles penetrate the attached sludge, exhibiting a jacking effect that separates the sludge particles. These effects are further enhanced by hot water. Therefore, sludge attached to the inner wall surface of wastewater pipes can be completely removed. Also, because the attached sludge is finely pulverized, the sludge that peels off the inner wall surface of the wastewater pipe is removed without clogging as it flows down the vertical pipe, eliminating the risk of blockage. Note that if the water pressure is less than 2.0 MPa, the attached sludge becomes difficult to remove. Here, the preferred water pressure ranges from 2.0 to 12.0 MPa, depending on the nominal diameter of the cleaning nozzle used. If the water pressure exceeds 12.0 MPa, the cleaning equipment becomes excessive. A more preferred water pressure ranges from 2.0 to 10.0 MPa. Furthermore, the method for imparting ultrafine bubbles to water may be carried out in a pipe through which water flows, or in a water storage tank. The hot water of the present invention only requires heating room temperature water (generally in the range of 5°C to 20°C) to 30°C or higher. In the present invention, the structure and specifications of the steps for imparting ultrafine bubbles to water, pressurizing water, and heating water are not particularly limited.

[0013] In the present invention, if we consider only the cleaning ability to crush and remove attached sludge containing oil, it is effective to increase the water temperature. However, in order to minimize adverse effects on wastewater pipes (especially thermal expansion and contraction of PVC pipes), the hot water of the present invention has a cleaning operating range of 45°C or less, and ultrafine bubbles that do not adversely affect wastewater pipes are added to complement its cleaning ability. In one aspect of the present invention, the water temperature of the ultrafine bubble high-pressure hot water is within the range of 30°C to 45°C when it passes through the tip nozzle. In this aspect, since the upper limit of the water temperature is defined, adverse effects on wastewater pipes due to heat can be avoided. It is ideal to control the water temperature at the tip nozzle, but it is easier to control it at the base end of the hose. More preferably, the water temperature is within the range of 35°C to 45°C when it flows through the nozzle, and more preferably within the range of 40°C to 45°C.

[0014] In one aspect of the present invention, the tip nozzle ejects hot water in both its forward path, traveling longitudinally through the wastewater pipe, and its return path, traveling longitudinally away from the wastewater pipe. In this aspect, ultrafine bubble high-pressure hot water is injected into the wastewater pipe in both its forward path and its return path. Therefore, even if there is a relatively large amount of attached sludge or if it is relatively stubborn, the attached sludge is sufficiently softened and finely pulverized, thus eliminating the risk of blockage due to detached sludge. In another aspect, the ultrafine bubble high-pressure hot water is injected into the wastewater pipe in at least one of the forward or return paths of the tip nozzle.

[0015] The structure of the nozzle tip is not particularly limited, but in a preferred aspect of the present invention, the nozzle tip comprises a base fixed to the end of a hose, a rotating part rotatably attached to the base, and a nozzle hole provided on the rotating part from which ultrafine bubble high-pressure hot water is ejected. In this aspect, the ultrafine bubble high-pressure hot water ejected from the rotating part is sprayed over the entire circumference of the inner wall surface of the wastewater pipe. Therefore, any remaining attached sludge is eliminated. In another aspect, the nozzle tip may not have a rotating part.

[0016] Preferably, the ultrafine bubble high-pressure hot water is almost equivalent to pure water, containing virtually no impurities other than residual chlorine, like tap water, and is harmless to the human body. Furthermore, to prevent bubbling during the cleaning of wastewater pipes from disrupting airflow and breaking the trap seal, it is preferable that the ultrafine bubble high-pressure hot water does not contain various chemicals such as surfactants, gelling agents, and solidification accelerators, as well as chemicals such as hypochlorite, hydrogen peroxide, various cleaning chemicals, and other main components of toiletries, and ozone. In a preferred aspect, the wastewater pipe cleaning system of the present invention uses tap water to produce the ultrafine bubble high-pressure hot water, and does not involve a step of adding chemicals to this tap water. In this aspect, since the ultrafine bubble high-pressure hot water does not contain ozone or chemicals, it does not damage parts such as ethylene propylene diene rubber (EPDM) used in the packing of wastewater pipe joints.

[0017] The wastewater pipe cleaning system of the present invention comprises an ultrafine bubble generating unit that imparts ultrafine bubbles with a diameter of less than 1 μm to the water passing through it; a water storage tank that stores the ultrafine bubble water flowing in from the ultrafine bubble generating unit; a high-pressure unit that pressurizes the ultrafine bubble water flowing in from the water storage tank; a hot water unit that heats the ultrafine bubble high-pressure water flowing in from the high-pressure unit; a hose made of a flexible material, having a base end connected to the hot water unit and a tip end that passes through the wastewater pipe, through which the ultrafine bubble high-pressure hot water flows; and a tip nozzle attached to the end of the hose that ejects the ultrafine bubble high-pressure hot water. [Effects of the Invention]

[0018] According to the present invention as described above, the sludge adhering to the inner wall surface of the miscellaneous drainage pipe can be completely peeled off. Also, even when there is relatively a large amount of adhering sludge or when it is stubborn, the peeled-off sludge is sufficiently softened and loosened, its fluidity is increased, the risk of blockage of the miscellaneous drainage pipe is eliminated, and it contributes to the improvement of the efficiency of cleaning work. Further, it can respond to new lifestyles and can also respond to miscellaneous drainage containing various chemicals such as gelling agents and solidification accelerators for toiletries and the like.

Brief Description of the Drawings

[0019] [Figure 1] It is an overall view showing an embodiment of the present invention. [Figure 2] It is a schematic diagram showing a state of cleaning a miscellaneous drainage pipe. [Figure 3] It is a view showing the tip nozzle inside the miscellaneous drainage pipe. [Figure 4] It is a photograph showing a comparison of the results of the cleaning method of the present invention and the conventional cleaning method.

Modes for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIG. 1 is a longitudinal sectional view showing a cleaning system for a miscellaneous drainage pipe according to an embodiment of the present invention. The system of this embodiment includes an ultra-fine bubble generation unit 11, a water storage tank 21, a high-pressure unit 31, a hot water unit 41, a hose 44, and a tip nozzle 51. The water supplied from a water source not shown is given ultra-fine bubbles, pressurized, and heated in the process of passing through these units.

[0021] The ultra-fine bubble generating unit 11 has a first inlet 12 and a first outlet 13. The downstream end of a pipeline 17 such as a hose is connected to the first inlet 12. The upstream end of the pipeline 17 (not shown) is connected to a water source (such as a water supply pipe, a sprinkler faucet, or a water storage tank) not shown. When water flows from the water source through the pipeline 17 to the first inlet 12 due to the water pressure of a water supply pipe or the like, ultra-fine bubbles are imparted to the water when it passes through the ultra-fine bubble generating unit 11, and ultra-fine bubble water containing ultra-fine bubbles flows out from the first outlet 13. Ultra-fine bubbles refer to fine bubbles with a diameter of less than 1 μm. In this embodiment, it is made to contain 70 million or more ultra-fine bubbles per 1 mL of water. Also, in this embodiment, when water passes through the ultra-fine bubble generating unit 11, in addition to ultra-fine bubbles, micro-bubbles with a diameter of 1 μm or more and milli-bubbles with a diameter larger than that of micro-bubbles may be imparted by the ultra-fine bubble generating unit 11. Note that "ultra-fine bubbles" is a registered trademark of the Fine Bubble Industry Association, a general incorporated association, which designates a fine bubble generating device as a specified product.

[0022] The ultra-fine bubble generating unit 11 is a cylindrical device and has a first inlet 12 and a first outlet 13 at both ends of the device. The first inlet 12 is connected to the water source described above, and the first outlet 13 is connected to the second inlet 22 of the water storage tank 21. The ultra-fine bubble generating unit 11 of this embodiment generates ultra-fine bubbles from the air already dissolved in the inflowing water. Also, since the ultra-fine bubble generating unit 11 of this embodiment may be connected to a sprinkler faucet (generally with a water pressure of about 0.2 to 0.3 MPa) installed in an apartment house, it is preferable that the first inlet 12 corresponds to a water pressure of around 0.2 MPa.

[0023] A second inlet 22 is provided at a higher position in the water storage tank 21, and a second outlet 23 is provided at a lower position. The first outlet 13 of the ultrafine bubble generation unit 11 is connected to the second inlet 22 of the water storage tank 21. The ultrafine bubble water, to which a predetermined number of ultrafine bubbles have been added by the ultrafine bubble generation unit 11, is temporarily stored in the water storage tank 21. Because there is a large pressure loss when the water passes through the ultrafine bubble generation unit 11, by installing the ultrafine bubble generation unit 11 and the water storage tank 21 that stores the water that has passed through it upstream of the high-pressure unit 31, a system can be created that ensures a stable supply of ultrafine bubble water without affecting the water pressure of the tip nozzle 51. The ultrafine bubbles do not immediately rise to the water surface and disappear in the water storage tank 21, but remain in the water for a while. The second outlet 23 of the water storage tank 21 is connected to the third inlet 32 ​​of the high-pressure unit 31 via a pipe 24 such as a hose.

[0024] The high-pressure unit 31 has a third inlet 32 ​​and a third outlet 33, as well as an internal pump (pressurizing unit) for drawing in and discharging water. The third outlet 33 of the high-pressure unit 31 is connected to the fourth inlet 42 of the hot water unit 41 via a conduit 34 such as a pressure-resistant hose.

[0025] The high-pressure unit 31 draws water from the water storage tank 21 through the third inlet 32, pressurizes the water to a predetermined water pressure, and discharges it from the third outlet 33. The predetermined water pressure is set appropriately according to the specifications, nominal diameter, and size of the tip nozzle 51 used, taking into account the head to the cleaning location where the tip nozzle 51 is placed, the friction loss determined by the nominal diameter and length of the hose 44, and other pressure losses. For example, if the nominal diameter of the tip nozzle 51 is 1 / 8 inch, a corresponding water pressure of 3 to 5 MPa is required, and if the nominal diameter of the tip nozzle 51 is 1 / 4 inch, a corresponding water pressure of 8 to 10 MPa is required, in addition to the water pressure corresponding to the head, friction loss, and pressure loss mentioned above. The high-pressure unit 31 may also be a self-propelled high-pressure cleaning vehicle equipped with a high-pressure washer. The high-pressure cleaning vehicle may further include at least one of the hot water unit 41, the water storage tank 21, and the ultrafine bubble generating unit 11.

[0026] The hot water unit 41 includes a fourth inlet 42 and a fourth outlet 43, as well as an internal heating element that generates heat using a fuel such as kerosene, and heats the water flowing in from the fourth inlet 42. The temperature of the heated hot water is in the range of 30 to 60°C, preferably in the range of 40 to 45°C. This hot water flows out from the fourth outlet 43.

[0027] The hose 44 is made of a flexible material such as resin and has a base end and a tip. The base end of the hose 44 is connected to the fourth outlet 43. A tip nozzle 51 is attached to the tip of the hose 44. Thus, as shown in Figure 1, the wastewater pipe cleaning system of the present invention includes an ultrafine bubble generating unit 11 having a first inlet 12 and a first outlet 13 and imparting ultrafine bubbles with a diameter of less than 1 μm to the water passing from the first inlet 12 to the first outlet 13; a water storage tank 21 having a second inlet 22 and a second outlet 23, the second inlet 22 being connected to the first outlet 13 and storing the ultrafine bubble water flowing in from the second inlet 22 and discharging it from the second outlet 23; a third inlet 32 ​​receiving the ultrafine bubble water discharging from the second outlet 23 and a pressurizing unit pressurizing the ultrafine bubble water flowing in from the third inlet 32 ​​and pressurized The system includes a high-pressure unit 31 having a third outlet 33 for discharging ultrafine bubble high-pressure water, a hot water unit 41 having a fourth inlet 42 for receiving the ultrafine bubble high-pressure water flowing out from the third outlet 33, a heating section for heating the ultrafine bubble high-pressure water flowing in from the fourth inlet 42, and a fourth outlet 43 for discharging the heated ultrafine bubble high-pressure hot water, a hose 44 made of a flexible material through which the ultrafine bubble high-pressure hot water flows, having a base end connected to the fourth outlet 43 and a tip that passes through a wastewater pipe, and a tip nozzle 51 attached to the tip of the hose 44 for spraying ultrafine bubble high-pressure hot water.In this embodiment, these units are prepared separately, for example by a vehicle, and connected in series with each other.In modified cases not shown, the connection order of these units may be different.In modified cases not shown, multiple units may be integrated.

[0028] Figure 3 is a magnified view of the entire tip nozzle 51. The tip nozzle 51 is rotatable and has a base 52 fixed to the end of the hose 44, a rotating part 53 rotatably attached to the base 52, a nozzle hole 54 provided in the rotating part 53 from which water is ejected, and a tip portion 55 that protrudes further toward the end from the rotating part 53. The rotating part 53 rotates due to the water flow supplied from the hose 44. The rotation axis O of the rotating part 53 passes through the center of the base 52 and the tip portion 55 and is concentric with the end region of the hose 44. The nozzle hole 54 is directed toward the outer diameter side when viewed from the rotation axis O. The nozzle hole 54 is also directed at an angle of inclination that is slightly tilted toward the hose 44 side (i.e., the root side) with respect to a perpendicular line perpendicular to the rotation axis O. The tip portion 55 is an axial member that rotatably supports the rotating part 53, and the end of the tip portion 55 (not shown) is fixed to the base 52. Furthermore, the tip portion 55 is provided with a flange to prevent the rotating portion 53 from coming off. The shape and number of nozzle holes 54 are appropriately designed to ensure adequate rotational force, sufficient water volume and pressure, and uniform spraying into the drain pipe.

[0029] Next, the method of using the cleaning system of this embodiment will be described.

[0030] Figure 2 is a schematic diagram illustrating the piping of the wastewater pipes to be cleaned. The wastewater pipes include horizontal pipes 101, 102, and 103 that mainly extend horizontally in the private areas of the apartment building, and vertical pipes 105 that mainly extend vertically in the common areas of the apartment building. The upstream ends of horizontal pipes 101, 102, and 103 are connected to bowl-shaped traps 106 in the bathroom floor, bowl-shaped traps 107 in the washing machine pan floor, S-shaped traps 108 under the washroom sink, and bowl-shaped traps 109 in the kitchen sink, respectively. The downstream ends of horizontal pipes 101 to 103 are connected to vertical pipe 105. Traps 106 to 109 have a structure that constantly holds water to block odors and pests from the downstream wastewater pipes, creating a water seal. Horizontal pipes 101 to 103 have lengths of several meters to match the size of the private area. The vertical pipe 105 has a length of several meters to tens of meters, and sometimes up to 100 meters, to match the height of the apartment building. The opening 111 at the upper end of the vertical pipe 105 is open to the atmosphere. The lower end of the vertical pipe 105 (not shown) extends outside the apartment building and connects to the sewer pipe. The toilet bowl 112 is separated from the graywater pipe and connected to the sewage pipe 113. When managing the process and work of cleaning the inside of the pipes, the sewage pipe and the graywater pipe are distinguished. This is because a sufficient amount of water flows through the sewage pipe each time the toilet is used, so sludge is less likely to adhere to the sewage pipe compared to the graywater pipe.

[0031] The procedure for cleaning wastewater pipes begins with the worker preparing a hose 44 that is longer than the wastewater pipe to be cleaned. Next, the tip of the hose 44, i.e., the nozzle 51, is inserted into the traps 106-109 or opening 111 at the upstream end of the wastewater pipe, and the horizontal pipes 101-103 and vertical pipe 105 are cleaned. The following describes a typical method for cleaning the vertical pipe 105.

[0032] The hose 44 is gradually extended into the wastewater pipe by the worker, and the nozzle 51 moves through the wastewater pipe from upstream to downstream or downstream to upstream. Simultaneously with this movement, the nozzle 51 sprays high-pressure hot water containing the ultrafine bubbles described above.

[0033] The wastewater pipes in the common areas, specifically the vertical pipe 105, are relatively large in diameter, and are therefore cleaned with the aforementioned nozzle 51 with a nominal diameter of 1 / 4 inch. The wastewater pipes in the private areas, specifically the horizontal pipes 101-103, are relatively small in diameter, and are therefore cleaned with the aforementioned nozzle 51 with a nominal diameter of 1 / 8 inch.

[0034] In special cases, for example, if there is an elbow or the like upstream of the vertical pipe 105 and the tip nozzle 51 with a nominal diameter of 1 / 4 inch cannot pass through, as shown in Figure 2, it is advisable to allow the tip nozzle 51 with a nominal diameter of 1 / 8 inch, which advances from trap 107 or trap 109, to reach the vertical pipe 105 and clean the vertical pipe 105. In such cases, this can be addressed by overlap cleaning, where the cleaning areas of the tip nozzles 51, 51 overlap in the cleaning process of each floor.

[0035] Figure 3 is a cross-sectional view of a wastewater pipe showing how ultrafine bubble high-pressure hot water sprayed from the tip nozzle 51 removes attached sludge from the inner wall surface of the wastewater pipe. The tip nozzle 51 in this embodiment is a rotating nozzle that continuously rotates while spraying water onto the inner wall surface of the wastewater pipe. Ultrafine bubble high-pressure hot water W is sprayed outward from the nozzle hole 54 of the rotating part 53 while it is rotating. The spray direction is radially outward from the rotation axis O of the rotating part 53, and is approximately equal to the radially outward of the wastewater pipe. In addition, the spray direction of the ultrafine bubble high-pressure hot water W is inclined toward the hose 44 side. This gives the tip nozzle 51 thrust.

[0036] The ultrafine bubble high-pressure hot water, which has been heated by the hot water unit 41 to a temperature of 40°C to 45°C at the base end of the hose 44, decreases slightly when it is sprayed from the nozzle hole 54. Specifically, the temperature of the hot water sprayed from the nozzle hole 54 is 35 to 40°C. As an alternative, the hot water unit 41 may be heated to a higher temperature so that the water temperature at the tip nozzle 51 falls within the range of 40 to 45°C.

[0037] While higher water temperatures promote grease decomposition and increase the cleaning effect, there is a risk of adverse effects such as thermal distortion or cracking of the drainpipe if it is made of PVC. Therefore, it is preferable to keep the water temperature at the base of hose 44 below 45°C. Also, since the cleaning effect decreases with lower water temperatures, it is preferable to keep the water temperature at the base of hose 44 above 30°C. To compensate for the decrease in grease decomposition due to lower water temperatures, ultrafine bubbles are used in combination.

[0038] In this embodiment, the nozzle holes 54 are arranged opposite each other, straddling the axis of rotation O. In other words, multiple nozzle holes 54 are arranged rotationally symmetrically with respect to the axis of rotation O. The spray angles relative to the axis of rotation O are different from each other, or they may be the same. This ensures that the tip nozzle 51 is stable within the wastewater pipe. Furthermore, multiple nozzle holes 54 are arranged in stages with spacing in the direction of the axis of rotation O.

[0039] Furthermore, due to the rotation of the rotating part 53, the spray direction revolves around the rotation axis O. As a result, the ultrafine bubble high-pressure hot water W is sprayed over the entire circumference of the inner wall surface of the wastewater pipe. This ensures that the ultrafine bubble high-pressure hot water W is sprayed over the entire circumference of the inner wall surface of the wastewater pipe and evenly hits the attached sludge D.

[0040] If the attached sludge is relatively soft, as shown in Figure 3, in the wastewater pipe through which the tip nozzle 51 passes in the outward journey, the attached sludge D is peeled off, loosened or softened, fragmented, and made more fluid by the injection of ultrafine bubble high-pressure hot water W. Alternatively, if the attached sludge is relatively stubbornly attached in the outward journey, the attached sludge D is softened and loosened by the injection of ultrafine bubble high-pressure hot water W in the return journey. The cleaning is not limited to one round trip, but may be performed more times (for example, two round trips). The sludge E peeled off and loosened from the inner wall surface of the wastewater pipe flows smoothly down the wastewater pipe with the water and does not clog the inside of the wastewater pipe.

[0041] It should be added that the cleaning effect of ultrafine bubble high-pressure hot water is stronger than that of ordinary high-pressure room-temperature water. Furthermore, it is stronger than high-pressure hot water containing bubbles such as millibubbles. This is because, unlike ordinary water bubbles visible to the naked eye, ultrafine bubbles have surfactant properties and exhibit hydrophobic adsorption properties to adsorb oil and grease. Also, the surface of the ultrafine bubbles is negatively charged, which contributes to their adsorption properties. From a microscopic perspective, the minute ultrafine bubbles penetrate into the attached sludge and exert a jack-up effect that separates the sludge particles from each other. These effects are reinforced by the hot water. Thus, it is thought that ultrafine bubble high-pressure hot water dissolves the oil and protein in the attached sludge into the hot water and finely pulverizes it.

[0042] Returning to the explanation of the progress of the nozzle 51, the worker continues to gradually extend the hose 44 into the wastewater pipe, until the nozzle 51 reaches the downstream end of the wastewater pipe. This completes the cleaning process on the outward journey.

[0043] Next, the worker gradually pulls back the hose 44. The tip nozzle 51 then moves backward from the downstream side to the upstream side of the wastewater pipe. As described above, during this backward movement, ultrafine bubble high-pressure hot water W is sprayed outward from the nozzle hole 54 of the rotating part 53. The attached sludge D that was loosened in the forward pass is pulverized and peeled off from the inner wall surface of the wastewater pipe. The ultrafine bubbles also increase the fluidity of the sludge. When the tip nozzle 51 reaches the upstream end of the wastewater pipe, the cleaning process on the return pass is completed.

[0044] According to the cleaning method of this embodiment, the surfactant effect of ultrafine bubbles and the effect of hot water eliminate the risk of blockage in the downstream section of the wastewater pipe during cleaning.

[0045] Furthermore, according to this embodiment, the rotating part 53 rotates and the ultrafine bubble high-pressure hot water W is sprayed over the entire circumference of the wastewater pipe, so that the attached sludge is uniformly peeled off from the inner wall surface of the wastewater pipe. Therefore, there is no unevenness in the removal of attached sludge.

[0046] Furthermore, according to this embodiment, since the nozzle holes 54 are arranged rotationally symmetrically with respect to the rotation axis O, the tip nozzle 51 does not roll. Therefore, the tip nozzle 51 does not collide with the inner wall surface of the wastewater pipe, which is beneficial for wastewater pipes that are weaker in strength than metal pipes, such as polyvinyl chloride pipes. As a modification, the tip nozzle 51 may be of a non-rotating type.

[0047] Furthermore, according to this embodiment, unlike water containing chemical substances or drugs such as foaming agents, detergents, surfactants, gelling agents, solidification accelerators, thickeners, and enzymes, the water does not become fluffy and foamy when sprayed, so that ventilation problems such as the water seal of traps 106 to 109 breaking do not occur during cleaning work.

[0048] Furthermore, according to this embodiment, tap water is used, and since no ozone or cleaning agents are added to the water, it is harmless to the human body, does not damage rubber gaskets or other gaskets installed in wastewater pipes, and is beneficial for metal pipes with low chemical resistance.

[0049] A cleaning effectiveness test was conducted on the cleaning method of this embodiment. First, the results of the cleaning method and cleaning system of the present invention and the results of the conventional cleaning method and cleaning system are shown in comparison in Figure 4. In Figure 4, the upper part, shown as Proportional Comparison 1, is the result of the conventional cleaning method. Also in Figure 4, the lower part, shown as Example 1, is the result of the cleaning method of the present invention. Both Proportional Comparison 1 and Example 1 in Figure 4 are half-cut wastewater pipes, and the half-cut pipes are shown opened to reveal the inner wall surface of the wastewater pipes.

[0050] The specifications and cleaning procedure of the cleaning system of Example 1, which is an embodiment of the present invention, are as shown in Table 1 below.

[0051] [Table 1]

[0052] In Table 1, the high-pressure washer is the same as the high-pressure unit 31 shown in Figure 1. The hot water washer is the same as the hot water unit 41. The UFB (Ultra Fine Bubble) generator is the same as the ultra-fine bubble generating unit 11. These units are commercially available products manufactured by the companies or with the model numbers listed in Table 1.

[0053] In contrast, the specifications of the conventional proportional 1 cleaning system do not include an ultrafine bubble generating unit or a hot water unit, and the high-pressure unit that produces high-pressure ambient temperature water (20°C) is the same as that of the high-pressure washer shown in Table 1. Other conditions and cleaning procedures are the same as or similar to those in Example 1.

[0054] The cleaning results are shown in comparison to the photograph in Figure 4. In Figure 4, the upper side shows Proportionality 1, and the lower side shows Example 1. In both cases, the wastewater pipes cleaned by the cleaning method using the cleaning system described above have been cut in half to expose the inner wall surface. In Proportionality 1, there are some remaining particles, but in Example 1, there are no remaining particles. From Figure 4, it was confirmed that Example 1 has a sufficient cleaning effect.

[0055] Although embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to the illustrated embodiments. Various modifications and variations can be made to the illustrated embodiments within the same scope as the present invention, or within an equivalent scope. [Industrial applicability]

[0056] This invention can be advantageously utilized in the cleaning industry. [Explanation of Symbols]

[0057] 11 Ultrafine bubble generating unit, 21 Water storage tank, 31 high-pressure unit, 41 hot water unit, 44 hoses, 51 Tip nozzle, 53 Rotating part, 54 Nozzle hole.

Claims

1. A hose with a nozzle at its end is passed through the wastewater pipe. Ultrafine bubble high-pressure hot water, containing 70 to 100 million ultrafine bubbles with a diameter of less than 1 μm per 1 mL, having a water temperature of 30°C or higher and a water pressure of 2.0 MPa or higher, is supplied to the base end of the hose as it passes through the tip nozzle. A method for cleaning a wastewater pipe, comprising moving the tip nozzle in the longitudinal direction of the wastewater pipe while ejecting the ultrafine bubble high-pressure hot water from the tip nozzle to remove sludge adhering to the inner wall surface of the wastewater pipe.

2. The method for cleaning a wastewater pipe according to claim 1, wherein the water temperature of the ultrafine bubble high-pressure hot water is within the range of 30°C to 45°C when it passes through the tip nozzle.

3. The method for cleaning a wastewater pipe according to claim 1, wherein the tip nozzle ejects the ultrafine bubble high-pressure hot water in both a forward path, which moves longitudinally along the wastewater pipe, and a return path, which moves longitudinally away from the wastewater pipe.

4. The method for cleaning a wastewater pipe according to claim 1, wherein the tip nozzle has a base fixed to the tip of the hose, a rotating part rotatably attached to the base, and a nozzle hole provided on the rotating part from which the ultrafine bubble high-pressure hot water is ejected.

5. The method for cleaning wastewater pipes according to claim 1, wherein the ultrafine bubble high-pressure hot water is produced from tap water and does not involve the step of adding chemical substances to the tap water.

6. An ultrafine bubble generating unit that imparts ultrafine bubbles with a diameter of less than 1 μm to the water passing through it, A water storage tank for storing ultrafine bubble water flowing in from the ultrafine bubble generation unit, A high-pressure unit pressurizes the ultrafine bubble water flowing in from the aforementioned water storage tank, A hot water unit that heats the ultrafine bubble high-pressure water flowing in from the aforementioned high-pressure unit, A hose made of a flexible material has a base end connected to the hot water unit and a tip end that passes through the wastewater pipe, through which ultrafine bubble high-pressure hot water flows, A wastewater pipe cleaning system comprising a tip nozzle attached to the aforementioned tip for ejecting ultrafine bubble high-pressure hot water.

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