Apparatus and method for cleaning piping system

Abstract

To provide a flushing device which can be easily installed in a piping system, can shorten the time required for flushing, and can reduce the amount of drainage.SOLUTION: This cleaning device 1 is used for flushing a piping system P. The filter is composed of a strainer 6 connected to a piping system P and having a built-in screen 9, a single structure filter 12 mounted inside the screen 9 at the time of flushing and composed only of a relatively coarse filter, and a composite structure filter 14 composed of a combination of a relatively coarse filter and a relatively fine filter, and can be switched between a state of performing flushing by mounting the single structure filter 12 inside the screen 9 and a state of performing flushing by mounting the composite structure filter 14 inside the screen 9.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a cleaning device and a cleaning method used for cleaning (flushing) a piping system of a heat source device or an air conditioner before a test run of the device. [Background technology]

[0002] Flushing of piping systems in building facilities is carried out at construction sites to remove sludge (impurities) remaining in the pipes, such as soil and dust that has entered the pipes during temporary placement or transportation due to poor protection of the pipe ends, welding slag generated during pipe welding work, and metal chips generated during thread processing work, in order to clean the inside of the pipes. Insufficient flushing can cause corrosion of air conditioning pipes, blockage of strainers, and damage to equipment.

[0003] Conventional flushing involves repeatedly filling the pipe with water, circulating the water, and draining the water until the water quality in the pipe reaches the target level, as shown in Figure 20. However, this method has problems such as the long flushing time and the large amount of wastewater generated.

[0004] Another known method of simple flushing is to use a strainer. A strainer is a filtering device that uses a built-in screen with a specified mesh size to capture sludge in the fluid flowing through the piping. However, it is unable to capture sludge with a particle size smaller than the mesh size of the built-in screen. Such small sludge must be drained through a drain pipe separately installed in the piping system and removed along with the drainage. Therefore, draining and refilling the piping requires a significant amount of time, and requires the use of a large amount of water, which is problematic.

[0005] In recent years, as disclosed in Patent Document 1 and Non-Patent Document 1 below, a method has been proposed in which a temporary water treatment device is connected to the piping system as a bypass and water is treated by this water treatment device.

[0006] Patent Document 1 listed below discloses a system in which a temporary water treatment device equipped with a pump is connected to a flushing piping system as a bypass, and part of the circulating water is transported to a water treatment unit and returned to the flushing piping system after treatment.

[0007] Furthermore, the following Non-Patent Document 1 discloses a system in which a temporary water treatment device (bag filter) is connected to a flushing piping system as a bypass, a valve is provided in the piping system, and by operating this valve, the entire amount of flushing water is transported to the water treatment device and returned to the flushing piping system after treatment. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 6524032 [Non-patent literature]

[0009] [Non-Patent Document 1] Iida et al., A Study on the Completion Criteria for Flushing Closed Air Conditioning Piping, Proceedings of the Annual Meeting of the Society of Heating, Air-Conditioning and Sanitary Engineers of Japan (September 16-18, 2015), 2015, pp. 241-243 Summary of the Invention [Problem to be solved by the invention]

[0010] However, the method of bypassing a temporary water treatment device as disclosed in Patent Document 1 and Non-Patent Document 1 requires prior consideration of the installation location of the water treatment device, the method of transporting it in and out, etc., which imposes restrictions on the installation of the water treatment device and requires a significant amount of time to install the water treatment device. Furthermore, if the diameter of the bypass piping is smaller than the diameter of the piping of the flushing piping system, the water treatment flow rate decreases, making it difficult to say that efficient cleaning can be performed.

[0011] SUMMARY OF THE INVENTION It is therefore a primary object of the present invention to provide a piping system cleaning device and cleaning method that can be easily installed in a piping system, shorten the time required for flushing, and reduce the amount of wastewater. [Means for solving the problem]

[0012] In order to solve the above problems, the present invention according to claim 1 provides a cleaning device used for flushing a piping system, comprising: The filter comprises a strainer connected to the piping system and having a built-in screen, a single-structure filter that is attached to the inside of the screen during flushing and is made up of only a relatively coarse-mesh filter, and a composite-structure filter that is made up of a combination of a relatively coarse-mesh filter and a relatively fine-mesh filter, A piping system cleaning device is provided which is switchable between a state in which the single-structure filter is attached inside the screen and flushing is performed, and a state in which the composite-structure filter is attached inside the screen and flushing is performed.

[0013] In the invention described in claim 1, a strainer is connected to a piping system, and a filter is attached inside a screen built into the strainer to capture sludge in the fluid in the piping system. The filter attached inside the screen can be switched between a single-structure filter composed only of a relatively coarse-mesh filter and a composite-structure filter composed of a combination of a relatively coarse-mesh filter and a relatively fine-mesh filter, and flushing can be performed by switching between them. Therefore, by first attaching the single-structure filter and performing flushing, and then attaching the composite-structure filter and performing flushing, sludge in the fluid can be efficiently removed.

[0014] In this way, the cleaning device according to the present invention can be easily installed by utilizing a strainer connected to the piping system, without using a large-scale external water treatment device, and because the sludge in the fluid is collected by circulating water and passing it through the strainer, flushing can be performed without repeatedly filling and draining the water, thereby shortening the time required for filling and draining the water and reducing the amount of wastewater.

[0015] According to a second aspect of the present invention, there is provided the piping system cleaning device of the first aspect, wherein the strainer is a Y-strainer, a T-strainer or a straight strainer with the cylindrical screen built in.

[0016] In the invention described in claim 2, a Y-shaped strainer, a T-shaped strainer, or a straight strainer with a built-in cylindrical screen is used as the strainer. This is a concrete example of the main types of strainers used in building facilities, and it is also possible to configure the cleaning device according to the present invention using a strainer with a built-in cylindrical screen other than these.

[0017] According to a third aspect of the present invention, there is provided the piping system cleaning device of the first aspect, wherein the single-piece filter is formed by rolling a filter sheet from one end into a roll.

[0018] The invention described in claim 3 above prescribes a specific structure of the single-piece filter, which is configured by rolling a flat filter sheet from one end into a roll.

[0019] As a fourth aspect of the present invention, there is provided a piping system cleaning device as described in claim 1, in which the composite structure filter is configured by wrapping an outer filter made of a relatively fine-mesh filter sheet around the outer periphery of an inner filter made of a relatively coarse-mesh filter sheet rolled from the end into a roll.

[0020] In the invention described in claim 4 above, if a fine-mesh filter is packed inside the screen, the differential pressure before and after the strainer will increase, which may cause the screen to break or the circulation flow rate to be insufficient, preventing the sludge inside the piping system from being transported. Therefore, a composite structure filter is formed by wrapping a relatively fine-mesh filter around the outer periphery of a relatively coarse-mesh filter.

[0021] The present invention according to claim 5 provides a piping system cleaning device according to claim 1, wherein the single-structure filter and the composite-structure filter are each mounted inside the screen and arranged to fill the inside of the screen.

[0022] In the invention described in claim 5 above, the single-structure filter and the composite-structure filter are each mounted inside the screen, and are arranged so that each filter is filled inside the screen, so that the fluid in the piping system reliably passes through the filter and is purified.

[0023] The present invention according to claim 6 provides a cleaning device according to claim 1, in which a cylindrical spacer having open ends and a large number of through holes formed on the circumferential surface is disposed in the center of at least one of the single-structure filter and the composite-structure filter, thereby reducing pressure loss.

[0024] In the invention of claim 6, a hollow cylindrical spacer is disposed in the center of at least one of the single-structure filter and the composite-structure filter, so that the pressure loss before and after the strainer can be further reduced.

[0025] The present invention according to claim 7 provides a cleaning method used for flushing a piping system, comprising: A strainer having a built-in screen is connected to the piping system, a first step of circulating a fluid through the piping system with a single-piece filter configured only with a relatively coarse filter attached inside the screen; The method for cleaning a piping system is characterized by comprising a second step of replacing the filter installed inside the screen with a composite structure filter consisting of a combination of a relatively coarse-mesh filter and a relatively fine-mesh filter, and circulating a fluid through the piping system.

[0026] In the invention described in claim 7 above, flushing is performed in a first step of circulating the fluid through the piping system with the single-structure filter attached inside the screen of a strainer connected to the piping system, and a second step of replacing the filter attached to the screen with the composite-structure filter and circulating the fluid through the piping system. Therefore, no large-scale external water treatment device is required, and installation is easy by utilizing the strainer connected to the piping system. In addition, sludge can be captured in the strainer simply by circulating water without repeatedly filling and draining the water, which shortens the time required for flushing and reduces the amount of wastewater.

[0027] The present invention according to claim 8 provides a method for cleaning a piping system according to claim 7, which, if the cleanliness does not satisfy the target value at the stage when the second step is completed, carries out a third step of supplying water from a water supply pipe connected to the piping system and draining water from a water drain pipe connected to the piping system, and performing a water exchange process on the flushing water until the target cleanliness is achieved.

[0028] In the invention described in claim 8 above, after the first and second steps of capturing sludge by circulating water through a filter attached inside the screen of the strainer, only if the cleanliness does not satisfy the target value at the stage when the second step is completed is the third step of replacing the flushing water by supplying water from the water supply pipe and draining it from the water drain pipe. This makes it possible to reduce the amount of fresh water injected into the piping system compared to the conventional method in which water is supplied and drained from the early stages of flushing.

[0029] The present invention according to claim 9 provides the method for cleaning a piping system according to claim 7, wherein the water circulation in the first step and the second step is carried out so that the fluid circulates through the piping system 20 to 40 times, respectively.

[0030] In the invention described in claim 9 above, the results of preliminary tests revealed that the gradient of decrease in cleanliness is large immediately after the start of water circulation, but that the gradient of decrease in cleanliness becomes almost zero once the number of circulations reaches a certain level (20 to 40 times or more).Therefore, a decision is made to end the process and move on to the next process when the number of circulations reaches 20 to 40, at which point the gradient of decrease in cleanliness becomes almost zero. [Effects of the Invention]

[0031] As explained above in detail, according to the present invention, the device can be easily installed in a piping system, the time required for flushing can be shortened, and the amount of wastewater can be reduced. [Brief explanation of the drawings]

[0032] [Figure 1] 1 is a system diagram of a piping system P in which a piping system cleaning device 1 according to the present invention is arranged. [Figure 2] FIG. 2 is a cross-sectional view of a strainer 6. [Figure 3] 10 is a diagram showing how to attach a single-piece filter 12 to a screen 9. FIG. [Figure 4] 10 is a diagram showing how to attach a composite structure filter 14 to a screen 9. FIG. [Figure 5] FIG. 1 is a perspective view showing a composite structure filter 14 in which a cylindrical spacer 15 is arranged. [Figure 6] 1 is a flow chart showing a method for cleaning a piping system according to the present invention. [Figure 7] FIG. 1 is a piping plan view showing an experimental device. [Figure 8] FIG. 8 is a view taken along the line VIII-VIII in FIG. 7. [Figure 9] FIG. 9 is a view taken along the line IX-IX in FIG. 7. [Figure 10]10 is a graph showing the evaluation results of the removal performance of the single-piece structure filter 12. [Figure 11] 10 is a graph showing the results of comparing the removal performance of each filter. [Figure 12] 1 shows the pressure loss curves of each filter. [Figure 13] 1 shows the pressure loss curves of each filter. [Figure 14] 10 is a graph showing the results of a comparison of removal performance with and without a cylindrical spacer 15. [Figure 15] This is a piping diagram around the air conditioning unit 3 used in the actual experiment. [Figure 16] 10 is a graph showing the results of a comparison of flushing operation times for hot and cold water systems. [Figure 17] 10 is a graph showing the results of a comparison of flushing operation times in a reheat hot water system. [Figure 18] 10 is a graph showing the comparison results of the amount of drainage in the flushing operation. [Figure 19] 1 is a graph showing the change in turbidity of flushing water when the present invention is implemented. [Figure 20] FIG. 10 is a flow chart showing a conventional flushing procedure. DETAILED DESCRIPTION OF THE INVENTION

[0033] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0034] [Pipe cleaning device 1] The piping system cleaning device 1 according to the present invention can be applied to all piping systems used in ordinary air conditioning equipment. As an example of such a piping system P, as shown in Fig. 1, there is one that is configured with a heat source device 2 installed outdoors, an air conditioning device 3 installed indoors, and a cooling / heating medium piping 4 connected to these and through which a heat transfer fluid is circulated by a pump or the like. The cooling / heating medium piping 4 may include a chilled / hot water piping, a cooling water piping, a reheated hot water piping, and the like, each arranged as an independent piping system. Furthermore, gate valves 5 are provided on the inlet and outlet sides of the heat source device 2 and the air conditioning device 3 of the cooling / heating medium piping 4, respectively.

[0035] A strainer 6 is installed upstream of each piece of equipment to prevent damage to the heat source equipment 2, air conditioning equipment 3, pumps, heat exchange coils, and other equipment due to sludge mixed in with the fluid flowing through the piping system P. In the example shown in Fig. 1, the strainer 6 is installed in the piping on the inlet side of the heat source equipment 2.

[0036] A wide variety of well-known strainers can be used as the strainer 6, and as shown in Fig. 2, it is composed of a hollow main body 7 having an inlet and an outlet, and a capture section 8 that communicates with the middle of the main body 7 and has a screen 9 with many openings that capture sludge in the fluid. The capture section 8 is provided with an outlet through which the built-in screen 9 can be removed, and this outlet is closed by a lid 10.

[0037] The flow of fluid within the strainer 6 is such that the fluid flows into the main body 7 from the inlet, flows into the interior of the screen 9 from the upper end opening of the screen 9, passes through the numerous through holes formed on the peripheral surface and bottom surface of the screen 9, flows out of the screen 9, and then flows out from the outlet of the main body 7.

[0038] The strainer 6 is available in various shapes such as a Y-shaped strainer, a T-shaped strainer, a straight strainer, and a U-shaped strainer, and any of these may be used, but it is preferable to use a strainer that allows the screen 9 to be easily attached and detached.

[0039] The screen 9 is formed in a cylindrical shape with one end open and one end closed, and is made of punched metal, wire mesh, wedge wire, or the like, with numerous through-holes on both the periphery and bottom. The mesh size of the screen 9 is determined by the size of the through-holes; a small mesh size can capture small foreign objects, while a large mesh size can only capture large foreign objects. The mesh size may be within a commonly used range, but it is preferable to use a wire mesh with a mesh size of approximately 40 mesh, as specified in JIS G 3555 and JIS G 3556, with reference to the standard specifications for public building construction.

[0040] The cleaning device 1 of the present invention comprises the strainer 6, a single-structure filter 12 that is attached inside the screen 9 during flushing and is composed only of a relatively coarse-mesh filter (coarse filter sheet 11), and a composite-structure filter 14 that is composed of a combination of a relatively coarse-mesh filter (coarse filter sheet 11) and a relatively fine-mesh filter (dense filter sheet 13), and is switchable between a state in which the single-structure filter 12 is attached inside the screen 9 and flushing is performed, and a state in which the composite-structure filter 14 is attached inside the screen 9 and flushing is performed.

[0041] The single-piece filter 12 is composed of a single relatively coarse filter sheet 11, and is formed so that the material composition and porosity are approximately constant throughout the filter. The coarse filter sheet 11 can be made of porous materials such as nonwoven fabric, woven fabric, or sponge. However, it is preferable to use nonwoven fabric, which can stably set the porosity and has good sludge collection efficiency. The material fibers constituting the nonwoven fabric can be any one of synthetic fibers such as olefins (e.g., polyethylene or polypropylene), polyesters, and polyamides, recycled fibers (e.g., rayon or cupra), semi-synthetic fibers (e.g., acetate), and natural fibers (e.g., cotton), or a combination of two or more thereof. Nonwoven fabrics obtained by suitable processing methods such as spunlace, spunbond, thermal bond, meltblown, and needlepunch can be used.

[0042] 3(A), the single-piece filter 12 is formed by forming a roughly rectangular, flat coarse filter sheet 11 having long and short sides into a predetermined shape. The length of the short side of the coarse filter sheet 11 is approximately the same as the height (axial length) of the screen 9.

[0043] The single-piece filter 12 is formed by rolling the coarse filter sheet 11 from one end of its short side in the long side direction into a roll and processing it into a substantially cylindrical shape (FIGS. 3(B) and (C)), which is inserted into the screen 9 for use (FIG. 3(D)). The single-piece filter 12 is preferably formed so that the outer diameter of the single-piece filter 12 is approximately the same as the inner diameter of the screen 9, or the outer diameter of the single-piece filter 12 is formed slightly larger than the inner diameter of the screen 9, so that when the single-piece filter 12 is attached inside the screen 9, there is no gap between the single-piece filter 12 and the screen 9 and they are filled together. When the coarse filter 11 is wound into a roll, and when the rolled single-piece filter 12 is inserted into the screen 9, no compressive force that would drastically reduce the porosity of the coarse filter sheet 11 acts on the single-piece filter 12, and in the process of forming the roll-shaped single-piece filter 12 from the coarse filter sheet 11 and fitting it into the screen 9, the porosity hardly decreases, or the porosity of the outer periphery decreases slightly when the single-piece filter 12 is inserted into the screen 9. However, the reduction in porosity is 20 points or less, preferably 10 points or less, compared to the porosity of the original coarse filter sheet 11.

[0044] The coarse filter sheet 11 is composed of fibers with an average fiber diameter of 50 to 200 μm, preferably 80 to 120 μm, a thickness of 5 to 50 mm, preferably 10 to 30 mm, and a porosity of 70 to 99%, more preferably 93 to 99%. The average fiber diameter can be determined by averaging the fiber diameters measured from images of multiple locations magnified with an electron microscope. The thickness can be determined in accordance with Method A of the thickness test in JIS L 1913 General Nonwoven Fabric Testing Method. The porosity can be calculated from (100 - (weight / volume) / fiber specific gravity). The weight can be determined by multiplying the value measured in accordance with the mass per unit area test in JIS L 1913 General Nonwoven Fabric Testing Method by the area. The volume can be determined by multiplying the thickness by the area. The fiber specific gravity can be determined by the specific gravity in the chemical fiber filament yarn test method specified in JIS L 1013.

[0045] Next, the composite structure filter 14 is a filter configured by combining a relatively coarse filter sheet 11 and a relatively fine filter sheet 13, and is configured so that the porosity is smaller on the outer periphery than on the center of the filter. The coarse filter sheet 11 used in the single-piece structure filter 12 can be used as the coarse filter sheet 11.

[0046] As with the coarse filter sheet 11, porous materials such as nonwoven fabric, woven fabric, and sponge can be used for the dense filter sheet 13. However, it is preferable to use nonwoven fabric, which has a stable porosity and good sludge collection efficiency. The material fibers constituting the nonwoven fabric can be any one of synthetic fibers such as olefins such as polyethylene or polypropylene, polyesters, and polyamides, recycled fibers such as rayon or cupra, semi-synthetic fibers such as acetate, and natural fibers such as cotton, or a combination of two or more thereof. Nonwoven fabrics obtained by appropriate processing methods such as spunlace, spunbond, thermal bond, meltblown, and needlepunch can be used.

[0047] As shown in Fig. 4(A), the composite structure filter 14 is constructed by rolling a roughly rectangular, flat coarse filter sheet 11 having long and short sides into a roll by rolling it from one end of the short side in the long side direction to form an inner filter that is processed into a roughly cylindrical shape, and then wrapping and laminating an outer filter made of a dense filter sheet 13 around the outer periphery of the inner filter (Fig. 4(B)), and this is inserted into the screen 9 for use (Fig. 4(C)). It is preferable to form the outer diameter of the composite structure filter 14 to be roughly the same as the inner diameter of the screen 9, or to form the outer diameter of the composite structure filter 14 to be slightly larger than the inner diameter of the screen 9, so that when the composite structure filter 14 is installed inside the screen 9, there is no gap between the composite structure filter 14 and the screen 9 and they are filled together. When the coarse filter sheet 11 is wound into a roll, when the dense filter sheet 13 is wound and laminated around the outer periphery of the rolled coarse filter sheet 11, and when the composite-structure filter 14 is inserted into the screen 9, no compressive force that would drastically reduce the porosity of the coarse filter sheet 11 and the dense filter sheet 13 is applied to the composite-structure filter 14, and the porosity hardly decreases during the process of forming the composite-structure filter 14 and fitting it into the screen 9, or the porosity of the outer periphery decreases slightly when the composite-structure filter 14 is inserted into the screen 9. However, the reduction in porosity is 20 points or less, preferably 10 points or less, compared to the porosity of the original coarse filter sheet 11 and dense filter sheet 13.

[0048] The dense filter sheet 13 is made of fibers with an average fiber diameter of 1 to 49 μm, preferably 20 to 40 μm, a thickness of 5 to 50 mm, preferably 10 to 30 mm, and a porosity of 70 to 99%, more preferably 93 to 99%. The average particle diameter, thickness, and porosity are determined as described above. The dense filter sheet 13 uses fibers with a smaller average fiber diameter than the coarse filter sheet 11, and therefore has a finer mesh than the coarse filter sheet 11.

[0049] The dense filter sheet 13 may be wound in multiple layers around the outer periphery of the rolled-up coarse filter sheet 11, but it is preferable to wind only one layer. The dense filter sheet 13 has finer mesh than the coarse filter sheet 11, which may increase pressure loss and reduce the water circulation flow rate, and there is also a risk of damage to the screen 9 due to clogging of the filter, so it is preferable to wind only one layer.

[0050] As shown in Figure 5, a cylindrical spacer 15 with both ends open and a large number of through-holes formed on the periphery may be placed in the center of the composite filter 14 to reduce pressure loss. Experiments described below have shown that placing the cylindrical spacer 15 in the center of the composite filter 14 significantly reduces pressure loss and improves sludge removal efficiency. Note that Figure 5 shows an example in which the cylindrical spacer 15 is placed in the composite filter 14, but the cylindrical spacer 15 can be placed in at least one of the monolithic filter 12 and the composite filter 14.

[0051] The cylindrical spacer 15 is made of punched metal, wire mesh, or wedge wire, and has a large number of through holes formed on its circumferential surface. The cylindrical spacer 15 has approximately the same height (axial length) as the screen 9, and is disposed at the center of the hollow interior of the screen 9. Nothing is disposed in the hollow portion of the cylindrical spacer 15, leaving it hollow, and the single-structure filter 12 or composite-structure filter 14 is disposed between the outer circumferential surface of the cylindrical spacer 15 and the inner circumferential surface of the screen 9.

[0052] When the single-piece filter 12 is disposed on the outer periphery of the cylindrical spacer 15, the coarse filter sheet 11 is wound around the outer periphery of the cylindrical spacer 15 in one or more layers.

[0053] On the other hand, when arranging the composite structure filter 14 on the outer periphery of the cylindrical spacer 15, the coarse filter sheet 11 is wrapped around the outer periphery of the cylindrical spacer 15, and then the dense filter sheet 13 is wrapped around the outer periphery of this coarse filter sheet 11. The coarse filter sheet 11 and the dense filter sheet 13 may be wrapped in one layer or in multiple layers, but to prevent an increase in pressure loss, it is preferable to wrap at least the dense filter sheet 13 in one layer, and it is particularly preferable to wrap both the coarse filter sheet 11 and the dense filter sheet 13 in one layer. This allows cleaning to be performed reliably without increasing pressure loss in the cleaning device 1.

[0054] The inner diameter of the cylindrical spacer 15 can be determined appropriately depending on the inner diameter of the screen 9, the thicknesses of the coarse filter sheet 11 and the fine filter sheet 13, the number of wraps, and the thickness of the cylindrical spacer 15. For example, if the inner diameter of the screen 9 is 80 mm and a 20 mm thick coarse filter sheet 11 and an 18 mm thick dense filter sheet 13 are wrapped in one layer (total thickness of both sheets is 38 mm), and the thickness of the cylindrical spacer 15 is 2 mm, the inner diameter of the cylindrical spacer 15 can be 40 mm. In this case, the spatial ratio of the area of ​​the hollow portion of the cylindrical spacer 15 to the internal area of ​​the screen 9 in a cross-sectional view of the screen 9 is 39.1%.

[0055] The aperture ratio of the numerous through holes provided on the circumferential surface of the cylindrical spacer 15 (the ratio of the total area of ​​the through holes to the inner circumferential area of ​​the cylindrical spacer 15) is preferably 30 to 50%.

[0056] [Piping system cleaning method] Next, a method for flushing the piping system P using the cleaning device 1 will be described with reference to FIG.

[0057] As described above, the piping system P is connected to the strainer 6 having the screen 9 built therein.

[0058] In the first step, the single-piece filter 12 is attached to the screen 9 in advance, and the piping system P is filled with water and air is removed as needed.

[0059] Thereafter, with the unitary filter 12 installed inside the screen 9, the pump is operated to circulate the fluid through the piping system P. The water circulation in the first step is performed so that the fluid circulates through the piping system P 20 to 40 times. In other words, the water circulation is performed continuously for the circulation time obtained from the formula: Circulation time = (amount of water held in the piping system P / flow rate) x 20 to 40. As a result, during the water circulation, the fluid passes through the cleaning device 1 20 to 40 times, and during that time, sludge present in the fluid is captured by the unitary filter 12 of the cleaning device 1.

[0060] Regarding the water circulation flow rate during flushing, referring to a previous report (Umehara, Shinada, Takatsuka, "Flow rate required to remove foreign matter from pipes," New Japan Air Conditioning Technology Development Research Institute Technical Report No. 27, pp. 51-54 (2021)), it is best to adjust the pump frequency with a flow rate of 0.7 m / s or more as a guideline. This water circulation flow rate is also the same for the second process in the next step.

[0061] The decision to end the first step is made based on whether the turbidity measurement results have converged to the first order, with the number of circulations being approximately 20 to 40. In other words, the results of preliminary tests have revealed that the turbidity reduction gradient is large immediately after the start of water circulation, but once the number of circulations reaches a certain level (20 to 40 or more), the turbidity reduction gradient becomes almost zero (first order convergence).Therefore, the decision to end the first step and move on to the second step is made when the number of circulations reaches the first order, which is between 20 and 40, and the turbidity reaches first order convergence.

[0062] It is preferable to measure the turbidity when the water filling is completed before starting the water circulation. It is also preferable to measure the turbidity when the first step is completed.

[0063] Next, if it is determined in the first step that the turbidity has converged to the initial stage, the process proceeds to the second step. In the second step, first, the pump is stopped, the valves before and after the strainer 6 are closed, the cover 10 of the strainer 6 is opened, and the screen 9 is removed. Next, the single-piece filter 12 is removed from inside the screen 9, and after appropriate cleaning, the composite filter 14 is installed inside the screen 9.

[0064] Once the composite structure filter 14 is installed inside the screen 9, the screen 9 is attached to the strainer 6, the valves before and after the strainer 6 are opened, and then the pump is restarted to circulate the fluid through the piping system.

[0065] The determination of whether the second step is complete is made based on whether the turbidity measurement results have reached quadratic convergence or not, with the circulation number set to 20 to 40 times as a guide, in the same way as in the first step.

[0066] At the end of this second step, the turbidity is measured.

[0067] If the turbidity at the end of the second step satisfies the target value, the composite structure filter 14 is removed from inside the screen 9, the screen 9 is cleaned, and then returned to the inside of the strainer 6, completing the flushing.

[0068] If the turbidity at the end of the second step does not satisfy the target value, the third step is performed by simultaneously supplying water from the water supply pipe 16 connected to the piping system P and draining water from the water drain pipe 17 connected to the piping system P, and replacing the flushing water until the target turbidity is reached. This step is performed while measuring the turbidity at appropriate intervals along the way, until the turbidity satisfies the target value. This third step is performed as needed, and does not need to be performed if the turbidity satisfies the target value at the end of the second step. Performing the third step ensures that the turbidity satisfies the target value. Note that the indicator for determining the completion of flushing may be any indicator other than turbidity, as long as it can determine the cleanliness of the liquid, such as color or transparency.

[0069] In the present invention, after the above-mentioned first and second steps of circulating water through filters 12 and 14 attached inside screen 9 of strainer 6 to capture sludge in the fluid, only if the turbidity does not meet the target value at the end of step 2 is the third step of replacing the flushing water by simultaneously supplying water from water supply pipe 16 and draining water from drain pipe 17. This makes it possible to significantly reduce the amount of fresh water injected into the piping system P compared to conventional methods in which water is supplied and drained from the early stages of flushing. In other words, even when step 3 is necessary due to strict requirements for the target turbidity, the amount of fresh water used to flush piping system P can be minimized.

[0070] In the third step, methods of simultaneously supplying water from the water supply pipe 16 and draining water from the drain pipe 17 include a method in which fresh water is injected and diluted while circulating the fluid in the piping system P with a pump, and the water is drained while being drained, and a piston flow-like replacement method in which fresh water is injected from one side and drained from the other side while the pump is stopped.Either method can be used, but the latter replacement method has the advantage that when fresh water is injected from one side of the piping system P and drained from the other side, a sudden drop in turbidity can be detected when the replacement is complete, making it easier to determine whether flushing is complete. [Example]

[0071] [Performance evaluation experiment of cleaning device 1] As shown in FIGS. 7 to 9, an experiment was conducted to evaluate the performance of the cleaning device 1 according to the present invention using a simple circulation type piping system P.

[0072] As shown in Figures 7 and 8, the piping system P used in the experiment has two water tanks 20, 21, and each water tank is connected to water supply pipes 22, 23 through which water is supplied from the water tank via water supply valves 24, 25, and to return water pipes 26, 27 through which water is returned to the water tank via return valves 28, 29. As shown in Figures 7 to 9, a flow path is formed in which water from the water supply pipes 22, 23 passes through the cleaning device 1, flow meter 30, and pump 31, and then returns to the return water pipes 26, 27. Valves 32, 33 are provided before and after the cleaning device 1.

[0073] In the experiment, foreign matter classified by particle size was introduced into one of the water tanks, the water from the one water tank was passed through piping system P and returned to the other water tank, and then the water from the other water tank was passed through piping system P and returned to the one water tank. This operation was repeated a predetermined number of times. More specifically, after the foreign matter was introduced into water tank 20, water supply valve 24 provided on water supply pipe 22 of water tank 20 was opened, water supply valve 25 provided on water supply pipe 23 of water tank 21 was closed, water return valve 28 provided on water return pipe 26 of water tank 20 was closed, and water return valve 29 provided on water return pipe 27 of water tank 21 was opened. In this state, pump 31 was operated, and the water in water tank 20 passed through water supply pipe 22 and cleaning device 1, then passed through water return pipe 27 and was stored in water tank 21. This process was repeated until water tank 20 was empty. Next, with water supply valve 24 on water supply pipe 22 of water tank 20 closed, water supply valve 25 on water supply pipe 23 of water tank 21 opened, water return valve 28 on water return pipe 26 of water tank 20 opened, and water return valve 29 on water return pipe 27 of water tank 21 closed, water in water tank 21 passes through water supply pipe 23 and cleaning device 1, then passes through water return pipe 26 and is stored in water tank 20. This process is repeated until water tank 21 is empty. The above two steps are counted as one cycle, and this operation was repeated 20 times to evaluate the removal performance of cleaning device 1. In other words, by repeating the above operation 20 times, water in piping system P passes through cleaning device 1 40 times. To replace the filter in cleaning device 1, front and rear valves 32 and 33 are closed and the built-in screen 9 is removed.

[0074] The particle size of the introduced foreign matter was known for five ranges: less than 53 μm, 53 μm to less than 100 μm, 100 μm to less than 250 μm, 250 μm to less than 425 μm, and 425 μm or more. Hereinafter, for convenience, these particle size ranges will be referred to as less than 53 μm, 53 to 100 μm, 100 to 250 μm, 250 to 425 μm, and 425 μm or more. When conducting experiments to evaluate the removal efficiency of fine particle size foreign matter, known particle sizes of the foreign matter were used for two ranges: 32 μm to less than 63 μm and 63 μm to less than 125 μm. Hereinafter, these ranges will be referred to as 32 to 63 μm and 63 to 125 μm for convenience.

[0075] First, the experiment was carried out by mounting the unitary structure filter 12 according to the present invention in the cleaning device 1. The coarse filter sheet 11 constituting the unitary structure filter 12 had an average fiber diameter of 100 μm, a thickness of approximately 20 mm, and a porosity of 95%.

[0076] The results of the experiment are shown in Figure 10. As a comparative example (without filter), the figure also shows the case where the single-piece structure filter 12 is not attached to the screen 9, and only the screen 9 is used.

[0077] Without a filter, the removal performance depends on the mesh size of the screen 9, so although the removal efficiency is poor, it is possible to remove foreign matter with a particle size of 425 μm or more, but the result was that foreign matter with a particle size smaller than that was hardly removed at all.

[0078] In contrast, it was confirmed that the cleaning device 1 equipped with the single-piece structure filter 12 had a high efficiency in removing foreign matter having a particle diameter of 100 μm or more.

[0079] Next, the experiment was carried out by mounting the same single-structure filter 12 as described above, the composite-structure filter 14 according to the present invention, and a fine-mesh filter (comparison example) in which an external fine-mesh filter was wound around the outer periphery of the single-structure filter 12, in the cleaning device 1. The foreign matter introduced was that used to evaluate the removal efficiency of fine foreign matter.

[0080] The coarse filter sheet 11 constituting the composite structure filter 14 was the same as described above, and the dense filter sheet 13 had an average fiber diameter of 30 μm, a thickness of approximately 18 mm, and a porosity of 95%. The fine filter used as a comparative example was made by wrapping a single layer of an external sheet with an average fiber diameter of 25 μm, a thickness of approximately 0.15 mm, and a porosity of 60% around the outer periphery of the coarse filter sheet 11 similar to the above.

[0081] The results of the experiment are shown in Figure 11. It was confirmed that the composite structure filter 14 can remove foreign matter with smaller particle diameters than the single-piece structure filter 12. In addition, when the fine mesh filter is used, it also shows removal performance equal to or better than that of the composite structure filter 14, but as will be described later, it has the disadvantage of increasing pressure loss.

[0082] Next, pressure gauges were placed before and after the strainer 6 to measure the pressure loss caused by the water passing through the strainer 6. The results are shown in Figure 12. As a comparative example (without a filter), the same figure also shows the case where no filter is attached to the screen 9, and only the screen 9 is used.

[0083] The pressure loss is greater when the single-structure filter 12 and the composite-structure filter 14 are installed than when no filter is used. Also, the pressure loss is greater with the composite-structure filter 14 than with the single-structure filter 12. When the fine filter is installed, the pressure loss becomes so large that there is concern about damage to the screen 9, as well as problems such as an insufficient water circulation flow rate and the tendency for foreign matter to become trapped inside the piping.

[0084] Next, the pressure loss across the strainer 6 was measured when the cylindrical spacer 15 was placed in the center of the single-structure filter 12 and the composite-structure filter 14. In addition, the removal efficiency of the composite-structure filter 14 was measured when the cylindrical spacer 15 was not installed and when it was installed.

[0085] As a result, as shown in Figure 13, the pressure loss before and after the strainer 6 was significantly reduced by installing the cylindrical spacer 15. For example, at a flow velocity of 1.5 m / s, inserting the composite structure filter 14 increased the pressure loss by about 60 kPa compared to without a filter, but by providing the cylindrical spacer 15, the increase in pressure loss was reduced to about 20 kPa compared to without a filter, achieving a pressure reduction of 40 kPa (about 67%). Furthermore, as shown in Figure 14, the provision of the cylindrical spacer 15 resulted in improved removal performance in the particle size range of 32 to 63 μm.

[0086] [Evaluation of cleaning method application to actual equipment] Next, at an actual construction site, the cleaning device 1 according to the present invention was applied to flushing of air conditioning equipment piping, and a comparative verification was carried out with respect to the work time and amount of water discharged, compared with conventional flushing (the method shown in Fig. 20). The construction site was a 13-story office building, and as shown in Fig. 1, an air-cooled heat pump chiller with a built-in pump was installed on the roof as heat source equipment 2, and air conditioning equipment 3 was installed on each floor. The actual equipment experiment was carried out on a hot and cold water system (water capacity 3.5 m 3 ), reheat hot water system (water capacity 2.6m 3 ) was performed in two systems.

[0087] Figure 15 shows a piping diagram around the air conditioner 3. In conventional flushing, as shown in Figure 20, water filling and blowing are performed two to three times as a pre-process of water circulation, and foreign matter in the piping is removed to some extent in advance. However, in the present invention, such a pre-process of water circulation is not performed. Therefore, if water from the piping system P is circulated through the air conditioner 3 from the beginning, foreign matter in the piping system P may flow into the coil of the air conditioner 3, leading to damage to the coil. For this reason, in this actual machine experiment, a temporary bypass pipe 40 was connected between the supply pipe and return pipe connected to the air conditioner 3, and closing flanges 41 were attached to each of the supply pipe and return pipe connected to the air conditioner 3, so that water in the piping system P would flow directly from the supply pipe to the return pipe through the bypass pipe 40 without flowing into the air conditioner 3.

[0088] The actual experiment was carried out according to the procedure shown in Figure 6. In the actual experiment, the turbidity of the flushing water was measured as the flushing progressed, and flushing was considered complete when it was confirmed that the turbidity had fallen below 20.

[0089] The cleaning device 1 is configured by attaching a single-structure filter 12 or a composite-structure filter 14 to the screen 9 of the strainer 6 provided near each heat source device 2 (air-cooled heat pump chiller) according to each process.

[0090] The specific procedure for the actual experiment is as follows: after installing the cleaning device 1, water is supplied to the piping system P through the water supply pipe 16 to fill it with water and remove air; after confirming that the piping system P is full of water, in the first step, water is circulated through the piping system P with the single-piece structure filter 12 attached to the screen 9.

[0091] The water circulation in the first step is performed continuously for 2 to 4 hours, with the aim of circulating the water through the piping system P 20 to 40 times, and is judged to have reached a primary convergence after that. Immediately after the water circulation starts, flushing water (initial water) is sampled from the drain pipe 17 and its turbidity is measured, and after the first step is completed, flushing water (first intermediate water) is sampled and its turbidity is measured.

[0092] After the first step is completed, the valves before and after the strainer 6 are closed, the screen 9 is removed and washed, and then replaced with the composite structure filter 14. As the second step, water is circulated through the piping system P again.

[0093] The water circulation in the second step is similar to the first step, with the aim of circulating the water through the piping system P 20 to 40 times, and is continued for 2 to 4 hours, with the determination being made as to whether the turbidity has reached a second convergence. After the second step is completed, the flushing water (second intermediate water) is sampled and its turbidity is measured.

[0094] Next, in the third step, the valves of the water supply pipe 16 and the water drain pipe 17 are opened, and water is supplied to and drained from the piping system P at the same time.

[0095] Flushing water is sampled and its turbidity measured as appropriate, and once it is confirmed that the turbidity is below 20 degrees, the valves on the water supply pipe 16 and the water drain pipe 17 are switched to close, stopping the water supply and drainage.

[0096] Finally, the valves before and after the strainer 6 are closed, the screen 9 is removed, the composite structure filter 14 is collected, the screen 9 is washed, and then returned to the strainer 6 to complete the flushing.

[0097] A comparison of the operation time between conventional flushing (the method shown in Figure 20) and the cleaning method according to the present invention is shown in Figures 16 and 17, and a comparison of the amount of water discharged is shown in Figure 18. In comparing the operation time, the operation time for conventional flushing was calculated assuming that the time required for draining water is equivalent to the time required for water supply.

[0098] 16 and 17, the cleaning method according to the present invention does not require water changes (filling with water and replacing the water by draining) in the piping system P, so the time required for draining and supplying water for water changes can be significantly reduced. The cleaning method according to the present invention reduced work time in the chilled / hot water system by 28% compared to one water change, 55% compared to two water changes, and 68% compared to three water changes. In the reheated hot water system, the reduction was 34% compared to one water change, 54% compared to two water changes, and 68% compared to three water changes.

[0099] 18, in terms of the amount of water discharged, conventional flushing discharges the same amount of water as the water held in the piping system for each water change, whereas the cleaning method according to the present invention completes the work with a discharge amount less than the amount of water held in the piping system P. Therefore, in the case of a chilled or hot water system, the cleaning method according to the present invention reduces the amount of water discharged by 49% compared to one water change, 74% compared to two water changes, and 83% compared to three water changes. Also, in the case of a reheated hot water system, the reduction was 31% compared to one water change, 65% compared to two water changes, and 77% compared to three water changes.

[0100] As a result, the cleaning method according to the present invention can reduce the work time and amount of wastewater required for flushing compared to conventional flushing.

[0101] Next, the change in turbidity of the flushing water is shown in Figure 19, and the analysis results of the flushing water are shown in Table 1. The analysis items of the flushing water were determined based on the water quality standards (JRA GL-02-1994) set forth by the Japan Refrigeration and Air Conditioning Industry Association. [Table 1]

[0102] As shown in Figure 19, the turbidity decreases as the flushing operation progresses, and the turbidity of the water reaches 10 or less when the flushing operation is completed. In addition, the water quality also satisfied the standard values ​​for all items, confirming that there are no problems with the cleaning device 1 and cleaning method according to the present invention.

[0103] Generally, the amount of residue in the pipe at the start of flushing varies depending on the piping construction and management methods, resulting in increased or decreased flushing time and drainage volume. In this case, the only on-site pipe processing work was threading. Wiping after threading was carefully performed to prevent chips and cutting oil from entering the pipe. Welding work was performed in a factory, so the amount of contaminants generated on-site was relatively low. However, if welding work is performed on-site or if the piping materials stored on-site are not properly protected, the amount of contaminants entering the pipe increases, potentially increasing flushing time. Furthermore, because cutting oil is difficult to remove with filters, the amount of fresh water and drainage required for the third step is likely to increase if a large amount of cutting oil is present. When actually applying the present invention, by adopting protective and operational methods that prevent on-site contaminants from entering the pipe, the accuracy of the effects of the present invention, such as shortening flushing time and reducing the amount of fresh water and drainage, can be improved. [Explanation of symbols]

[0104] 1...Cleaning device, 2...Heat source equipment, 3...Air conditioning equipment, 4...Refrigerant piping, 5...Gate valve, 6...Strainer, 7...Main body, 8...Capturing part, 9...Screen, 10...Cover body, 11...Coarse filter sheet, 12...Single structure filter, 13...Dense filter sheet, 14...Composite structure filter, 15...Cylindrical spacer, 16...Water supply pipe, 17...Drain pipe, 20·21...Water tank, 22·23...Water supply pipe, 24·25...Water supply valve, 26·27...Return pipe, 28·29...Return valve, 30...Flow meter, 31...Pump, 32...Valve, 40...Bypass pipe, 41...Block flange

Claims

1. A cleaning device used for flushing a piping system, comprising: The filter comprises a strainer connected to the piping system and having a built-in screen, a single-structure filter that is attached to the inside of the screen during flushing and is made up of only a relatively coarse-mesh filter, and a composite-structure filter that is made up of a combination of a relatively coarse-mesh filter and a relatively fine-mesh filter, A piping system cleaning device characterized in that it is switchable between a state in which the single-structure filter is attached inside the screen and flushing is performed, and a state in which the composite-structure filter is attached inside the screen and flushing is performed.

2. 2. The piping system cleaning device according to claim 1, wherein the strainer is a Y-strainer, a T-strainer or a straight strainer in which the cylindrical screen is built-in.

3. 2. The piping system cleaning device according to claim 1, wherein the single-piece filter is formed by rolling a filter sheet from one end into a roll.

4. 2. The piping system cleaning device according to claim 1, wherein the composite structure filter is constructed by winding an outer filter made of a relatively fine-mesh filter sheet around the outer periphery of an inner filter made of a relatively coarse-mesh filter sheet rolled from one end into a roll.

5. 2. The piping system cleaning device according to claim 1, wherein the single-structure filter and the composite-structure filter are respectively mounted inside the screen and are arranged so as to fill the inside of the screen.

6. 2. The cleaning device according to claim 1, wherein a cylindrical spacer having open ends and a large number of through holes formed on its circumferential surface is disposed in the center of at least one of the single-structure filter and the composite-structure filter, thereby reducing pressure loss.

7. 1. A cleaning method used for flushing a piping system, comprising: A strainer having a built-in screen is connected to the piping system, a first step of circulating a fluid through the piping system with a single-piece filter configured only with a relatively coarse filter attached inside the screen; a second step of replacing the filter installed inside the screen with a composite structure filter consisting of a combination of a relatively coarse-mesh filter and a relatively fine-mesh filter, and circulating a fluid through the piping system.

8. 8. A piping system cleaning method according to claim 7, wherein if the cleanliness does not satisfy the target value at the time when the second step is completed, a third step is carried out in which water is supplied from a water supply pipe connected to the piping system and drained from a water drain pipe connected to the piping system, and flushing water is exchanged until the target cleanliness is achieved.

9. 8. The method for cleaning a piping system according to claim 7, wherein the water circulation in the first and second steps is carried out so that the fluid circulates through the piping system 20 to 40 times.

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