Branch pipe water-stopping device and branch pipe water-stopping method

Abstract

The present invention provides a branch pipe water-stopping device and branch pipe water-stopping method for safely and easily stopping the flow of water in branch pipes connected to a main pipe. [Solution] The container 32 has a through hole 34 located approximately in the center, and the inner surface of the through hole 34 is in close contact with the outer surface 22a of the branch pipe 22 so that the branch pipe 22 passes through the through hole 34, forming a sealed cooling space 40 between the outer surfaces 22a of the branch pipe 22. The refrigerant introduction / discharge mechanism 33 introduces a refrigerant 45 from the outside into the cooling space 40 and discharges the introduced refrigerant 45 from the inside of the cooling space 40 to an appropriate position outside to cool the inside of the cooling space 40. The cold temperature inside the cooling space 40 freezes the fluid contained in the branch pipe 22, thereby stopping the water flow.

Description

Technical Field

[0001] The present invention relates to a branch pipe water stop device and a branch pipe water stop method for stopping the water flow in a branch pipe connected to a main pipe.

Background Art

[0002] For example, when replacing a fire hydrant housed in a pit underground, after closing the repair valve to stop the water flow, the fire hydrant is removed and replaced with a new one. However, when the repair valve cannot be closed due to corrosion or the like, or when no repair valve is provided, the water supply in the main pipe near the fire hydrant has to be cut off over a wide area.

[0003] In order to avoid such a wide area water cut-off, a method of locally stopping the water flow in a branch pipe that connects the main pipe and the fire hydrant is known (for example, see Patent Document 1).

[0004] Patent Document 1 discloses a non-stop flow method including a freezing step of freezing a part of the fluid in the branch pipe connected to the main pipe part 10 and / or in the main pipe part 10 facing the branch pipe part 11 while the fluid is flowing in the main pipe part 10, and a removing step of removing the piping element 12 installed in the branch pipe part 11 while the fluid is frozen. The reference numerals are those described in Patent Document 1.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the construction method described in Patent Document 1 involves setting up a formwork-like frame 3 to surround the outer circumference of the branch pipe section 11 and pouring the refrigerant into the frame 3, which makes it easy for the refrigerant to leak out from inside the frame 3. In particular, when the frame 3 is installed in the branch pipe section inside the pit and liquid nitrogen is used as the refrigerant, the pit becomes filled with nitrogen gas. If the concentration of nitrogen gas becomes high, it can cause problems due to oxygen deficiency. Therefore, there was a problem that ventilation using a ventilation fan or the like was necessary when using it inside a pit.

[0007] Therefore, a technical challenge arises in order to safely and easily stop the water flow in branch pipes connected to the main pipe, and the present invention aims to solve this challenge. [Means for solving the problem]

[0008] The present invention was proposed to achieve the above objective, and the invention described in claim 1 provides a branch pipe water-stopping device for stopping the flow of fluid contained in a branch pipe connected to a main pipe, comprising: a container having a through hole provided approximately in the center, the branch pipe being attached to the branch pipe with the branch pipe passing through the through hole, and a cooling space being formed between the container and the outer surface of the branch pipe; and a refrigerant introduction / discharge mechanism for introducing a refrigerant into the cooling space to cool the inside of the cooling space and for discharging the refrigerant introduced into the cooling space to the outside, thereby providing a branch pipe water-stopping device that freezes the fluid with the coldness in the cooling space to stop the flow.

[0009] With this configuration, a cooling space is formed between the inner surface of the container and the outer surface of the branch pipe, so even if liquid nitrogen is introduced as a refrigerant into the cooling space, leakage of nitrogen gas from the cooling space into the pit can be prevented. This prevents the pit from filling with nitrogen gas and causing damage due to oxygen deficiency. At the same time, the fluid contained inside the branch pipe that penetrates the container can be frozen, allowing for safe and easy water shutoff.

[0010] The invention described in claim 2 provides a branch pipe water-stopping device in which, in the configuration described in claim 1, the container is configured to be divisible into a plurality of radially arranged parts with respect to the through-hole.

[0011] With this configuration, each part, which is configured to be divisible radially around the through-hole, can be brought together from a direction approximately perpendicular to the outer surface of the branch pipe to easily form a single container through which the branch pipe passes, thereby improving work efficiency. In particular, when handling the container in sections, it is easier to attach the container to the outer surface of the branch pipe when working in a narrow pit space, further improving work efficiency.

[0012] The invention described in claim 3 provides a branch pipe water-stopping device in which, in the configuration described in claim 2, the container applies a caulking material to the abutting surfaces that face each other when the container halves, which are divided into a plurality of parts, are combined.

[0013] With this configuration, the gaps between the butt joints of each divided part are filled with caulking material, improving airtightness. Furthermore, the caulking material provides a strong adhesive bond between the butt joints, allowing the assembled state to be maintained more firmly.

[0014] The invention described in claim 4 provides a branch pipe water-stopping device in which the container is made of an insulating material, in the configuration described in claim 1.

[0015] With this configuration, heat conduction between the cooling space and the outside is blocked by the insulating material, so the temperature inside the cooling space can be maintained at the desired state.

[0016] The invention described in claim 5 provides a branch pipe water-stopping device in which, in the configuration described in claim 1, the container comprises an inner circumferential layer made of an insulating material and an outer circumferential layer made of a metal material that houses the inner circumferential layer.

[0017] With this configuration, heat conduction between the cooling space and the outside is blocked by the inner layer made of insulating material, so the temperature inside the cooling space can be maintained at the desired state. Furthermore, since the inner layer is housed in the outer layer made of metal, external impacts are absorbed by the outer layer made of metal, thereby increasing the strength of the container.

[0018] The invention described in claim 6 provides a branch pipe water shutoff device in which, in the configuration described in claim 1, the refrigerant introduction / discharge mechanism comprises a pipe-shaped refrigerant coil having a coil body portion disposed in the cooling space and wound around the outer surface of the branch pipe, a refrigerant introduction side pipe portion connected to the refrigerant introduction side at one end of the coil body portion, and a refrigerant discharge side pipe portion connected to the refrigerant discharge side at the other end of the coil body portion.

[0019] With this configuration, the refrigerant is passed through a pipe-shaped refrigerant coil having a coil body located within the cooling space, and not directly through the container, thus simplifying the removal of the refrigerant introduction / discharge mechanism after branch pipe shutoff work.

[0020] Furthermore, in order to achieve the above objective, the branch pipe water-stopping method described in claim 7 is a branch pipe water-stopping method for stopping the flow of fluid contained in a branch pipe connected to a main pipe, and includes a cooling space formation step of passing the branch pipe through a through hole provided in the approximate center of the container, attaching the container to the outer surface of the branch pipe, and forming a cooling space between the inner surface of the container and the outer surface of the branch pipe to cool the outer surface of the branch pipe, and a water-stopping step of introducing a refrigerant to cool the inside of the cooling space and discharging the refrigerant introduced into the cooling space to the outside.

[0021] According to this construction method, when a container is attached to the outer peripheral surface of the branch pipe, and then a refrigerant is introduced into the cooling space and discharged from the cooling space toward an appropriate external position so as to flow, the cooling space can be cooled. Then, the fluid accommodated inside the branch pipe penetrating through the container can be frozen, and water can be stopped safely and simply. Further, even if, for example, liquid nitrogen is introduced as a refrigerant into the cooling space formed between the inner peripheral surface of the container and the outer peripheral surface of the branch pipe, it is possible to easily suppress the leakage of nitrogen gas from the inside of the cooling space into the pit or the like. Thereby, it is possible to prevent the pit from being filled with gas and causing an obstacle due to oxygen deficiency.

Effect of the Invention

[0022] According to the present invention, even if, for example, liquid nitrogen is introduced as a refrigerant into the cooling space formed between the inner peripheral surface of the container and the outer peripheral surface of the branch pipe, the refrigerant enters the cooling space from the refrigerant inlet, and then is discharged from the cooling space through the refrigerant outlet to a predetermined location outside the container, and it is possible to easily prevent the nitrogen gas from leaking from the inside of the cooling space into the pit or the like. Therefore, problems such as the nitrogen gas inside the container leaking out and filling the pit, and causing an obstacle due to oxygen deficiency can be prevented. Further, while cooling the inside of the cooling space, the fluid accommodated in the branch pipe penetrating through the container can be frozen, and water can be stopped safely and simply.

Brief Description of the Drawings

[0023] [Figure 1] It is a partially cut-away side view showing an example of a fire hydrant used in a branch pipe water stop device according to a first embodiment of the present invention in a state of being installed in a pit. [Figure 2] It is a side view showing an initial state in which the branch pipe water stop device is attached to the branch pipe in the pit. [Figure 3] It is a view showing a state after the branch pipe water stop device is attached to the branch pipe in the pit and the refrigerant is flowed through the branch pipe water stop device, (a) is a view showing a state where the fire hydrant is removed, and (b) is an enlarged cross-sectional view of the A-A portion of (a) with the main pipe, refrigerant introduction hose, refrigerant discharge hose, etc. shown in (a) omitted. [Figure 4]It is a perspective view of the overall structure of the container of the branch pipe water stop device shown in FIGS. 2 and 3, where (a) is a view shown in the assembled state and (b) is a view shown in the disassembled state. [Figure 5] It is a longitudinal sectional side view showing a state where a container obtained by modifying a part of the container of the branch pipe water stop device shown in FIGS. 2 to 4 is attached to the branch pipe. [Figure 6] It is the container shown in FIG. 5, where (a) is an external perspective view of the entire container shown in the state of being removed from the branch pipe, and (b) is an exploded perspective view showing a part of the divided container. [Figure 7] It is a longitudinal sectional side view showing a state where the branch pipe water stop device of the second embodiment according to the embodiment of the present invention is attached to the branch pipe. [Figure 8] It is a view showing the external structure of the branch pipe water stop device shown in FIG. 7, where (a) is an external perspective view of the branch pipe water stop device shown in the state of being removed from the branch pipe, and (b) is an external perspective view of a half-container on one side of the divided container.

Embodiments for Carrying Out the Invention

[0024] The present invention is a branch pipe water stop device that stops the fluid contained in the branch pipe connected to the main pipe in order to safely and simply stop the flowing water in the branch pipe connected to the main pipe. A container having a through hole provided substantially at the center, the branch pipe being attached to the branch pipe in a state of passing through the through hole, and a cooling space being formed between the outer peripheral surface of the branch pipe; and a refrigerant introduction / discharge mechanism for introducing a refrigerant for cooling the inside of the cooling space into the cooling space and discharging the refrigerant introduced into the cooling space to the outside. The present invention is realized by freezing the fluid with the cold heat in the cooling space to stop the water.

Examples

[0025] Hereinafter, an example according to an embodiment of the present invention will be described in detail based on the accompanying drawings. In the following examples, when referring to the number, numerical value, amount, range, etc. of components, unless specifically stated or limited to a specific number in principle, it is not limited to that specific number, and it may be more or less than the specific number.

[0026] Furthermore, when referring to the shape, positional relationship, etc. of constituent elements, unless otherwise explicitly stated or in cases where it is clearly not the case in principle, this includes things that are substantially similar or analogous to those shapes, etc.

[0027] Furthermore, drawings may exaggerate features by enlarging characteristic parts to make them easier to understand, and the dimensional ratios of components may not be the same as in reality. Also, in cross-sectional drawings, hatching of some components may be omitted to make the cross-sectional structure of the components easier to understand.

[0028] Furthermore, in the following description, expressions indicating directions such as up and down or left and right are not absolute. They are appropriate when each part of the branch pipe water-stopping device of the present invention is depicted in that orientation, but should be interpreted accordingly if that orientation changes. Also, the same reference numerals are used for the same elements throughout the description of the embodiments.

[0029] Figure 1 shows an example of a fire hydrant used in the branch pipe water-stopping device according to the present invention. Figures 2 to 4 show a first embodiment of the branch pipe water-stopping device. Figure 2 is a side view showing the initial state in which the branch pipe water-stopping device is attached to a branch pipe in a pit. Figure 3 shows the state after the branch pipe water-stopping device is attached to a branch pipe in a pit and refrigerant has been flowed through the branch pipe water-stopping device. (a) shows the state with the fire hydrant removed. (b) is an enlarged cross-sectional view of part AA of (a), with the main pipe 21, refrigerant introduction hose 44A, refrigerant discharge hose 44B, etc. shown in (a) omitted. Figure 4 is a perspective view of the overall structure of the container of the branch pipe water-stopping device shown in Figures 2 and 3. (a) shows the assembled state. (b) shows the disassembled state.

[0030] In Figure 1, a branch pipe 22 is connected to the main pipe 21, extending radially along the main pipe 21 into the pit 20. A removable underground fire hydrant (hereinafter referred to as "fire hydrant 23"), described later, is installed at the upper end of the branch pipe 22 within the pit 20.

[0031] The pit 20 is an underground shaft excavated to form a roughly circular cross-section, and its inner surface is covered with a retaining wall 20a. Although not shown in the figure, the upper opening of the pit 20 is covered with a metal or other retractable lid.

[0032] The main pipe 21 carries the tap water L, which is a fluid. The main pipe 21 has a roughly circular cross-section and is made of metal, concrete, polyvinyl chloride, polyethylene, or polyolefin, etc. Alternatively, the inner surface of the main pipe 21 may be covered with epoxy resin, mortar, or the like.

[0033] A water passage is formed inside the fire hydrant 23, and the tap water L that flows into the fire hydrant 23 from the branch pipe 22 is drained outside the fire hydrant 23 through the water passage and outlet 24. The fire hydrant 23 includes a repair valve box section 25 and a fire hydrant box section 26.

[0034] A repair valve (not shown) is housed inside the repair valve casing 25. The repair valve can be opened and closed by rotating the handle 27. Note that a repair valve may not be provided in all cases. The repair valve casing 25 is detachably connected to the flange portion 22A, which is the upper end of the branch pipe 22. Note that if space is required between the repair valve casing 25 and the branch pipe 22, an extension pipe (not shown) may be installed between the repair valve casing 25 and the branch pipe 22.

[0035] The fire hydrant box section 26 is connected to the repair valve box section 25. The fire hydrant box section 26 houses a valve stem (not shown) that runs vertically through its interior. A key handle is inserted into a cap 28 provided at the upper end of the valve stem, and by manually rotating the cap 28 from the outside, the main valve provided at the lower end of the valve stem, which can open and close the water passage, can be moved up and down.

[0036] The fire hydrant box section 26 is equipped with a riser pipe section 29 that branches to the side. An outlet 24 is provided at the upper end of the riser pipe section 29. A fire hose (not shown) is connected to the outlet 24.

[0037] The above describes the general structure of the fire hydrant 23. Next, a branch pipe shut-off device 31 and branch pipe shut-off method for shutting off the water in the branch pipe 22 and replacing the fire hydrant 23 will be described. In this embodiment, when shutting off the water in the branch pipe 22 and replacing the fire hydrant 23, the branch pipe shut-off device 31 is used.

[0038] First, the structure of the branch pipe water-stopping device 31 will be described. As shown in Figures 2 to 4, the branch pipe water-stopping device 31 includes a container 32 that is installed in the pit 20 surrounding the outer surface 22a of the branch pipe 22, and a refrigerant introduction / discharge mechanism 33 that introduces and discharges refrigerant into the container 32.

[0039] In Figures 2 and 3, the container 32 is shown attached to the branch pipe 22, and in Figure 4, it is shown detached from the branch pipe 22. In Figures 2 to 4, the container 32 has a through hole 34 in the center, and is divided radially into two container halves, container half 32A and container half 32B, with the through hole 34 as the center. When in use, the two halves are butted together from a direction perpendicular to the outer surface 22a of the branch pipe 22, and the butt surfaces are fixed together to assemble and use as a single container 32.

[0040] Container halves 32A and 32B are formed approximately symmetrically, except that container halves 32A have an inspection window 36 on their outer surface 35, while container halves 32B do not. Note that the inspection window 36 may not be provided on either container halves 32A or 32B. In that case, container halves 32A and 32B are formed approximately symmetrically.

[0041] Furthermore, the container halves 32A and 32B are provided with flange portions 37 on the surfaces that abut each other. The flange portions 37 have mounting holes 39 for fixing the container halves 32A and 32B together with bolts and nuts 38. The through holes 34 are formed by semicircular notches 34a provided on the upper and lower surfaces of the container halves 32A and 32B, respectively.

[0042] Then, when assembling the container 32, first, as shown in Figure 4(b), the flange portion 37 of container half 32A and the flange portion 37 of container half 32B are butted together, and then bolts and nuts 38 are inserted into the mounting holes 39 of both flange portions 37 to fix them in place, thereby assembling a single, roughly cylindrical container 32 as shown in Figure 4(a). In the assembled container 32, through holes 34 are provided on the upper and lower surfaces, respectively, formed by the connection of notches 34a. The inner diameter of these through holes 34 is approximately equal to the outer diameter of the branch pipe 22, and when the container 32 is attached to the outer circumference of the branch pipe 22 by passing the branch pipe 22 through it from top to bottom, the outer surface 22a of the branch pipe 22 and the inner surface of the through hole 34 are in close contact. Furthermore, inside the container 32, as shown in Figure 3(b), a cooling space 40 is formed between the outer surface 22a of the branch pipe 22 and the inner surface of the container 32, which is tightly closed to the outer surface 22a of the branch pipe 22. Furthermore, if necessary, a sealing material is provided on the inner circumferential surface of the through-hole 34 to ensure airtightness of the cooling space 40.

[0043] In Figure 4(b), the container 32 is formed, for example, with an outer layer 41A made of metal, an intermediate layer 41B made of elastic rubber, and an inner outer layer 41C made of an insulating material such as expanded polystyrene. Furthermore, a gap is formed between the outer layer 41A and the intermediate layer 41B, with a projection 42 that protrudes toward the inner surface of the outer layer 41A from a part of the outer surface of the intermediate layer 41B, creating an air layer 41D that provides an insulating effect. The outer layer 41A, intermediate layer 41B, inner outer layer 41C, and air layer 41D insulate the space between the inside of the cooling space 40 and the outside of the container 32. In addition, the intermediate layer 41B, which is made of elastic rubber, and the inner outer layer 41C are housed within the outer layer 41A, which is made of metal that is resistant to external impacts, thereby providing protection against external impacts. Furthermore, the inspection window 36 provided in the container half 32A is used to check the volume of liquid nitrogen, which is the refrigerant described later, and is tightly sealed to the outer layer 41A. The material of the outer layer 41A is not limited to metal, but can be any material that is rigid enough to maintain the shape of the intermediate layer 41B and the inner outer layer 41C, such as a resin material such as polyvinyl chloride or carbon fiber. Also, the intermediate layer 41B is not limited to rubber, but can be a caulking material, for example, and it is even possible to omit the intermediate layer 41B.

[0044] The container 32 is provided with a refrigerant inlet 43A for introducing refrigerant 45 into the cooling space 40, and a refrigerant outlet 43B for discharging the refrigerant 45 from the cooling space 40 to the outside of the container 32. The refrigerant 45 used in this embodiment is, for example, liquid nitrogen, but other liquid refrigerants may also be used.

[0045] The refrigerant introduction / discharge mechanism 33 has a refrigerant introduction hose 44A and a refrigerant discharge hose 44B. One end of the refrigerant introduction hose 44A is connected to the refrigerant inlet 43A of the container 32, and the other end is connected to a refrigerant supply tank (not shown), allowing refrigerant 45 from the refrigerant supply tank to be introduced into the cooling space 40 through the refrigerant inlet 43A. On the other hand, one end of the refrigerant discharge hose 44B is connected to the refrigerant outlet 43B of the container 32, and the other end is led out to the outside of the pit 20. The refrigerant discharge hose 44B is used to discharge nitrogen gas generated in the cooling space 40 to the outside and to discharge the unwanted liquid nitrogen to a predetermined appropriate location outside the container 32.

[0046] Next, we will describe a branch pipe water-stopping method that uses a branch pipe water-stopping device 31 to stop the water flow in the branch pipe 22 and replace the fire hydrant 23.

[0047] <Cooling space formation process> First, the container 32 is placed in the pit 20 in its disassembled state, consisting of two halves, container 32A and container 32B. Then, the container halves 32A and 32B are butted together from both directions, with the abutting surfaces of their flange portions 37 facing the branch pipe 22. In this butt joint, the outer circumferential surface 22a of the branch pipe 22 is positioned and housed within the through-hole 34. With the flange portions 37 of container halves 32A and 32B butted together, bolts and nuts 38 are inserted into the mounting holes 39 of both flange portions 37 to secure them. As a result, the container 32 is attached to the outer circumferential surface 22a of the branch pipe 22, with the branch pipe 22 passing through the container 32 vertically. In this attached state, a tightly closed cooling space 40 is formed between the outer circumferential surface 22a of the branch pipe 22 and the inner circumferential surface 32a of the container 32.

[0048] <Water stop process> Next, one end of the refrigerant inlet hose 44A is connected to the refrigerant inlet 43A of the container 32, and one end of the refrigerant discharge hose 44B is connected to the refrigerant discharge port 43B of the container 32. The other end of the refrigerant inlet hose 44A is connected to the refrigerant supply tank, and the other end of the refrigerant discharge hose 44B is placed in a predetermined appropriate position outside the pit 20. Figure 2 shows this state.

[0049] Next, liquid nitrogen, which is the refrigerant 45, is introduced into the cooling space 40 from the refrigerant supply tank through the refrigerant introduction hose 44A and the refrigerant inlet 43A. The amount of liquid nitrogen introduced at this time can be seen from the outside through the inspection window 36. When liquid nitrogen is introduced into the cooling space 40, the branch pipe 22 is cooled by the liquid nitrogen over a required period of time, and the tap water L inside the branch pipe 22 is also frozen, becoming frozen tap water LC. Furthermore, the freezing of the tap water L causes the water inside the branch pipe 22 to stop flowing. Figure 3(b) shows the state in which the tap water L inside the branch pipe 22 has frozen into frozen tap water LC and the water has stopped flowing. In addition, the nitrogen gas generated in the cooling space 40 is discharged to the outside of the pit 20 through the refrigerant outlet 43B and the refrigerant discharge hose 44B and properly treated.

[0050] When the tap water L in the branch pipe 22 freezes and becomes frozen tap water LC, and the water supply in the branch pipe 22 is shut off, the fire hydrant 23 attached to the upper end of the branch pipe 22 is removed from the branch pipe 22 and replaced. During this replacement work, the degree of frost on the flange portion 22A of the branch pipe 22 is checked, and as a precaution, the fire hydrant 23 is opened to check if water comes out. Figure 3 shows the state after the fire hydrant 23 has been removed from the upper end of the branch pipe 22 after checking. After the replacement work of the fire hydrant 23 is completed and the new fire hydrant 23 is installed, the refrigerant 45 in the cooling space 40 is drained through the refrigerant discharge hose 44B. Furthermore, the container 32 is again disassembled into two parts, container half 32A and container half 32B, removed from the outer circumference of the branch pipe 22, and then removed from the pit 20 together with the refrigerant introduction hose 44A and the refrigerant discharge hose 44B. As a result, the condition shown in Figure 1 is achieved, and the freezing of the water supply L in the branch pipe 22 is resolved, allowing for normal use.

[0051] Therefore, in the configuration of the branch pipe water-stopping device 31 shown in the first embodiment, the inner surface of the through hole 34 of the container 32 is in close contact with the outer surface 22a of the branch pipe 22, and the cooling space 40 formed by the inner surface of the container 32 and the outer surface 22a of the branch pipe 22 is sealed. As a result, even if a refrigerant 45 such as liquid nitrogen is introduced into the cooling space 40, the refrigerant is introduced and discharged into the cooling space 40 through the refrigerant introduction hose 44A and the refrigerant discharge hose 44B, and nitrogen gas does not inadvertently leak from the inside of the cooling space 40 into the pit 20. This reliably prevents nitrogen gas from filling the pit 20 and causing problems due to oxygen deficiency. At the same time, the inside of the cooling space 40 is cooled, freezing the tap water L contained in the branch pipe 22 that penetrates the container 32, thereby safely and easily stopping the water flow. Furthermore, since the container 32 is divided into two parts, container half 32A and container half 32B, it is easier to attach the container 32 to the outer surface 22a of the branch pipe 22 even when working in a narrow space such as a pit 20, thereby improving work efficiency. In addition to two divisions, the container 32 may be divided into three or more parts centered on the through hole 34.

[0052] Figures 5 and 6 show a container 46 which is a modified version of the container 32 of the branch pipe water-stopping device 31 shown in Figures 2 to 4 as the first embodiment. More specifically, Figure 5 is a longitudinal cross-sectional side view showing the container 46 of the branch pipe water-stopping device 31 attached to the branch pipe 22. Figure 6 is the container 46 shown in Figure 5, where (a) is an overall perspective view of the container 46 removed from the branch pipe 22, and (b) is an exploded perspective view showing a part of the divided container 46. In the following description, the container 46 will be described as being used in place of the container 32 of the branch pipe water-stopping device 31 of the first embodiment shown in Figures 2 to 4. Therefore, in the following description, all parts other than the container 46 that correspond to the reference numerals of the first embodiment correspond to the parts of the branch pipe water-stopping device 31 of the first embodiment shown in Figures 2 to 4.

[0053] In Figures 5 and 6, the container 46 is formed as a roughly rectangular cube with a through hole 47 in the center and a roughly rectangular cubic cooling space 48 inside, and is molded from an insulating material such as expanded polystyrene, which has excellent heat insulation properties. The container 46 may also be molded in multiple layers, such as by covering the outer circumference with a metal material.

[0054] The container 46 is divided radially into four container halves 46A, 46B, 46C, and 46D, centered around a through hole 47. When in use, the four container halves 46A, 46B, 46C, and 46D are placed around the branch pipe 22, butted together from a direction perpendicular to the outer surface 22a of the branch pipe 22, and their abutting surfaces 46a are fixed together to assemble and use a single container 46. The through hole 47 is formed by arc-shaped notches 47a provided on the upper and lower surfaces of each of the container halves 46A, 46B, 46C, and 46D.

[0055] The container halves 46A, 46B, 46C, and 46D are basically formed in almost the same shape, but container half 46A is provided with an inspection window 36 and a refrigerant inlet 43A, and container half 46C is provided with a refrigerant outlet 43B, whereas container halves 46B and 46D do not have a refrigerant inlet 43A, an inspection window 36, or a refrigerant outlet 43B. The inspection window 36 provided in container half 46A is used to check the volume of liquid nitrogen, which is the refrigerant 45 described later, and is tightly sealed to container half 46A. In addition, the refrigerant inlet 43A can be connected to the refrigerant inlet hose 44A of the refrigerant inlet / discharge mechanism 33, and the refrigerant outlet 43B can be connected to the refrigerant discharge hose 44B of the refrigerant inlet / discharge mechanism 33.

[0056] Furthermore, as shown in Figure 6(b), when the container halves 46A, 46B, 46C, and 46D are combined to form a single container 46, one of the abutting surfaces 46a that meet each other is provided with an engaging recess 46c, and the other abutting surface 46a is provided with an engaging projection 46d that can be fitted into the engaging recess 46c.

[0057] Then, in assembling the container 46, the container halves 46A, 46B, 46C, and 46D are each placed with the branch pipe 22 in the center, and butted together from a direction perpendicular to the outer surface 22a of the branch pipe 22. The engaging protrusions 46d of the butt surfaces 46a are then fitted into the engaging recesses 46c to secure them. In addition, a sealant is applied to the butt surfaces 46a to fill the gap between them when butting. This sealant is, for example, silicone sealant or starch powder. These silicone sealants and starch powders harden with the cold air of a refrigerant 45 such as liquid nitrogen.

[0058] Next, we will explain the method of sealing off branch pipes 22 using a branch pipe sealing device 31 with a container 46, in the case of replacing a fire hydrant 23.

[0059] <Cooling space formation process> First, the container 46 is disassembled into container halves 46A, 46B, 46C, and 46D, and, if necessary, caulking material is applied to the abutting surfaces 46a before being placed in the pit 20. Then, the container halves 46A, 46B, 46C, and 46D are brought together by facing their abutting surfaces 46a toward the abutting surfaces 46a of adjacent container halves 46A, 46B, 46C, and 46D, and engaging the engaging protrusions 46d of the abutting surfaces 46a with the engaging recesses 46c of each. As a result, the adjacent container halves 46A, 46B, 46C, and 46D are joined together to form a single container 46. In this joined state, the outer circumferential surface 22a of the branch pipe 22 is positioned and housed within the through hole 47, and with the branch pipe 22 passing vertically through the container 46, the container 32 is attached to the branch pipe 22. Then, as shown in Figure 5, a tightly sealed cooling space 40 is formed inside the container 46 between the outer surface 22a of the branch pipe 22 and the inner surface of the container 46.

[0060] <Water stop process> Next, one end of the refrigerant inlet hose 44A is connected to the refrigerant inlet 43A of the container 46, and one end of the refrigerant discharge hose 44B is connected to the refrigerant discharge port 43B of the container 46. The other end of the refrigerant inlet hose 44A is connected to the refrigerant supply tank, and the other end of the refrigerant discharge hose 44B is placed in a predetermined appropriate position outside the pit 20.

[0061] Next, liquid nitrogen, which is the refrigerant 45, is introduced into the cooling space 40 from the refrigerant supply tank through the refrigerant introduction hose 44A and the refrigerant inlet 43A. The amount of liquid nitrogen introduced at this time can be seen from the outside through the inspection window 36. When liquid nitrogen is introduced into the cooling space 40, the branch pipe 22 is instantly cooled by the liquid nitrogen, and at the same time, the tap water L inside the branch pipe 22 freezes, becoming frozen tap water LC. Furthermore, the freezing of the tap water L also stops the flow inside the branch pipe 22. Figure 3 shows the state in which the tap water L inside the branch pipe 22 has frozen, becoming frozen tap water LC and stopping the flow. In addition, the nitrogen gas generated inside the cooling space 40 is discharged to the outside of the pit 20 through the refrigerant outlet 43B and the refrigerant discharge hose 44B and properly treated. Furthermore, when liquid nitrogen is introduced into the cooling space 40 and the container 46 is cooled, the caulking material applied to the abutting surfaces 46a of each container half 46A, 46B, 46C, and 46D hardens due to the cold air inside the container 46, and the abutting surfaces 46a of each container half 46A, 46B, 46C, and 46D are more firmly fixed together.

[0062] When the tap water L in the branch pipe 22 freezes and becomes frozen tap water LC, and the water supply in the branch pipe 22 is shut off, the fire hydrant 23 attached to the upper end of the branch pipe 22 is removed from the branch pipe 22 and replaced. During this replacement work, the degree of frost on the flange portion 22A of the branch pipe 22 is checked, and as a precaution, the fire hydrant 23 is opened to check if water comes out. Figure 5 shows the state after the fire hydrant 23 has been removed from the upper end of the branch pipe 22. After the replacement work of the fire hydrant 23 is completed and the new fire hydrant 23 is installed, the refrigerant 45 in the cooling space 40 is drained through the refrigerant discharge hose 44B. Furthermore, the container 46 is disassembled into multiple parts, removed from the outer circumference of the branch pipe 22, and removed from the pit 20 together with the refrigerant introduction hose 44A and the refrigerant discharge hose 44B. When disassembling the container 46 here, if it has been fixed with sealant, the adhesive will get in the way, so it is disassembled by cutting or other means. This resolves the freezing of the water supply in the branch pipe 22, allowing it to return to normal use.

[0063] Therefore, even in the case of a branch pipe water-stopping device 31 using a container 46, the inner surface of the through-hole 47 of the container 46 is in close contact with the outer surface 22a of the branch pipe 22, and the cooling space 40 formed by the inner surface of the container 46 and the outer surface 22a of the branch pipe 22 is sealed. As a result, even if liquid nitrogen is introduced into the cooling space 40 as a refrigerant 45, the refrigerant is introduced into and out of the cooling space 40 through the refrigerant introduction hose 44A and the refrigerant discharge hose 44B, and nitrogen gas does not inadvertently leak from inside the cooling space 40 into the pit 20. This reliably prevents nitrogen gas from filling the pit 20 and causing problems due to oxygen deficiency. At the same time, the cooling space 40 is cooled, and the tap water L contained in the branch pipe 22 that penetrates the container 46 is also frozen, allowing for safe and easy water-stopping. Furthermore, since the container 46 is divided into four container halves 46A, 46B, 46C, and 46D, it is easier to attach the container 46 to the outer surface 22a of the branch pipe 22 even when working in a narrow space such as a pit 20, thereby improving work efficiency. In addition to four divisions, the container 46 may also be divided into multiple parts such as two, three, or five parts centered on the through hole 47.

[0064] Figures 7 and 8 show a second embodiment of the branch pipe water-stopping device 51. More specifically, Figure 7 is a longitudinal cross-sectional side view showing the branch pipe water-stopping device 51 attached to the branch pipe 22 together with the branch pipe 22. Figure 8 shows the external structure of the branch pipe water-stopping device 51 shown in Figure 7, where (a) is an external perspective view of the branch pipe water-stopping device 51 removed from the branch pipe 22, and (b) is an external perspective view of one of the divided containers 52. In the following description, parts that are denoted by the same reference numerals as in Figures 1 to 4 are the same as the components shown in Figures 1 to 4.

[0065] In Figures 7 and 8, the branch pipe water-stopping device 51 includes a container 52 that is installed inside the pit 20 surrounding the outer surface 22a of the branch pipe 22, and a refrigerant introduction / discharge mechanism 53 that introduces and discharges refrigerant 45 into the container 52.

[0066] In Figure 7, the container 52 is shown attached to the branch pipe 22, and in Figure 8, it is shown detached from the branch pipe 22. In Figures 7 and 8, the container 52 has a through hole 54 in the center, and is divided into two container halves, container half 52A and container half 52B, radially from the through hole 54. When in use, the two halves are butted together from a direction perpendicular to the outer surface 22a of the branch pipe 22, and the butt surfaces are fixed together to assemble and use a single container 52.

[0067] The container halves 52A and 52B are formed to be approximately symmetrical. Furthermore, the container halves 52A and 52B are provided with flange portions 55 on the surfaces that abut each other. The flange portions 55 have mounting holes 55a for fixing the container halves 52A and 52B together with bolts and nuts 38. The through holes 54 are formed by semicircular notches 54a provided on the upper and lower surfaces of container halves 52A and 52B, respectively.

[0068] Then, when assembling the container 52, the flange portion 55 of container half 52A and the flange portion 55 of container half 52B are first butted together, and then bolts and nuts 38 are inserted into the mounting holes 55a of both flange portions 55 to fix them in place, thereby assembling a single, roughly cylindrical container 52 as shown in Figure 6(a). In this assembled container 52, through holes 54 are provided on the upper and lower surfaces, formed by the butting of the notches 54a of container half 52A and container half 52B, respectively. The inner diameter of these through holes 54 is approximately equal to the outer diameter of the branch pipe 22, and when the container 52 is attached to the outer circumference of the branch pipe 22 by passing it through from top to bottom, the outer surface 22a of the branch pipe 22 and the inner surface of the through holes 54 are in close contact. Furthermore, within the container 52, a cooling space 57 is formed between the outer circumferential surface 22a of the branch pipe 22 and the inner circumferential surface of the container 52, which is tightly sealed against the outer circumferential surface 22a of the branch pipe 22. If necessary, a sealing material is provided on the inner circumferential surface of the through hole 54.

[0069] The container 52 is formed with an outer layer 52C made of metal and an inner layer 52D made of an insulating material such as expanded polystyrene. The inner layer 52D is housed within the outer layer 52C, which is made of metal and resistant to external impacts, thereby protecting it from external shocks. At the same time, the outer layer 52C and the inner layer 52D provide insulation between the inside of the cooling space 57 and the outside of the container 52. The container 52 is also provided with an outlet 60a for leading out the refrigerant inlet pipe section 59B of the refrigerant coil 59, which is a refrigerant introduction / discharge mechanism 58 located inside the cooling space 57, and an outlet 60b for leading out the refrigerant discharge pipe section 59C of the refrigerant coil 59. The material of the outer layer 52C is not limited to metal; any material with sufficient rigidity to maintain the shape of the inner layer 52D is acceptable, such as resin or carbon fiber.

[0070] The refrigerant introduction / discharge mechanism 58 has the refrigerant coil 59 described above. The refrigerant coil 59 is made of a plastically deformable, pipe-shaped metal material that has high thermal conductivity and is soft, such as aluminum or copper. In addition, a pipe material with an inner diameter of about 5 to 10 mm is used, taking into consideration the ease of winding around the outer surface 22a of the branch pipe 22 and the ease of refrigerant passage. The refrigerant coil 59 is integrally provided with a refrigerant coil body 59A which is attached by winding it around the outer surface 22a of the branch pipe 22 multiple times, a refrigerant introduction side pipe 59B which can be drawn out to the outside of the container 52 by passing through the outlet 60a at one end of the refrigerant coil body 59A, and a refrigerant discharge side pipe 59C which can be drawn out to the outside of the container 52 by passing through the outlet 60b at the other end of the refrigerant coil body 59A. One end of the refrigerant inlet pipe section 59B is connected to a refrigerant supply tank (not shown) outside the pit 20, and one end of the refrigerant discharge pipe section 59C is led out to the outside of the pit. That is, refrigerant 45 flows into the refrigerant coil 59 from the refrigerant supply tank through the refrigerant inlet pipe section 59B, the refrigerant coil body section 59A, and the refrigerant discharge pipe section 59C. This refrigerant 45 is, for example, liquid nitrogen.

[0071] Next, we will explain a branch pipe water-stopping method that involves using a branch pipe water-stopping device 51 to stop the water flow in the branch pipe 22 and then replacing the fire hydrant 23.

[0072] <Cooling space formation process> First, the refrigerant coil 59 of the refrigerant introduction / discharge mechanism 58 is prepared. Then, inside the pit 20, the refrigerant coil body 59A is wound around the outer surface 22a of the branch pipe 22 multiple times in a coil shape, by turning it back and forth. In this winding of the refrigerant coil body 59A, as shown in Figure 7, the refrigerant coil body 59A wound around the outer surface 22a of the branch pipe 22 is wound and installed in a way that allows it to be accommodated in the cooling space 57.

[0073] Next, the container 52 is placed in the pit 20 in its disassembled state, consisting of two container halves, 52A and 52B. Then, the refrigerant inlet pipe section 59B is passed through the outlet 60a of container half 52A from the inside to the outside, and the refrigerant discharge pipe section 59C is passed through the outlet 60b of container half 52B from the inside to the outside, and the refrigerant coil 59 is attached to container half 52A and container half 52B.

[0074] Next, the container halves 52A and 52B are positioned opposite each other with their flange portions 55 facing each other towards the branch pipe 22, from a direction perpendicular to the outer circumferential surface 22a of the branch pipe 22, so that the outer circumferential surface 22a of the branch pipe 22 is positioned and housed within the through-hole 54. Then, as shown in Figure 7, the refrigerant coil body 59A is positioned within the cooling space 57. Subsequently, with the flange portions 55 of container half 52A and container half 52B butted together, a bolt and nut 38 are inserted into the mounting holes 55a of both flange portions 55 to secure them. As a result, the refrigerant coil body 59A and the container 52 surround the outer circumferential surface of the branch pipe 22, and the refrigerant coil 59 and the container 52 are attached to the branch pipe 22 with the branch pipe 22 passing through the container 52 vertically. In this mounting configuration, a tightly sealed cooling space 57 is formed between the outer surface 22a of the branch pipe 22 and the inner surface 52a of the container 52, preventing the cold air in the cooling space 57 from leaking out of the container 52. In this case as well, applying a sealant to fill the gap between the container halves 52A and 52B will provide even better sealing.

[0075] <Water stop process> Next, the other end of the refrigerant inlet pipe section 59B is connected to the refrigerant supply tank, and the other end of the refrigerant discharge pipe section 59C is placed in a predetermined position outside the pit 20. Figure 7 shows this state.

[0076] Next, liquid nitrogen, which is the refrigerant 45, is introduced from the refrigerant supply tank into the refrigerant coil 59 from the refrigerant inlet pipe section 59B. When liquid nitrogen is introduced into the cooling space 40 via the refrigerant coil 59, the branch pipe 22 is cooled by the refrigerant coil body section 59A, which is wound around the outer surface 22a of the branch pipe 22. At the same time, the tap water L inside the branch pipe 22 freezes and becomes frozen tap water LC. Furthermore, the freezing of the tap water L also stops the flow inside the branch pipe 22. Figure 7 shows the state in which the tap water L inside the branch pipe 22 has frozen into frozen tap water LC and stopped the flow. In addition, the nitrogen gas generated inside the refrigerant coil 59 is discharged to the outside of the pit 20 through the refrigerant discharge pipe section 59C and properly treated.

[0077] If the water supply in the branch pipe 22 freezes and stops, the fire hydrant 23 attached to the upper end of the branch pipe 22 is removed from the branch pipe 22 and replaced. During this replacement work, the degree of frost on the flange portion 22A of the branch pipe 22 is checked, and as a precaution, the fire hydrant 23 is opened to check if water comes out. Figure 7 shows the state after the fire hydrant 23 has been removed from the upper end of the branch pipe 22. After the replacement work of the fire hydrant 23 is completed and the new fire hydrant 23 is installed, the refrigerant 45 in the refrigerant coil 59 is drained through the refrigerant discharge side pipe 59C. Furthermore, the container 52 is disassembled into container half 52A and container half 52B, and removed from the refrigerant coil 59 and taken out of the pit 20. Next, the refrigerant coil 59 that was wrapped around the outer surface 22a of the branch pipe 22 is removed from the branch pipe 22. As a result, the condition shown in Figure 1 is achieved, and the freezing of the water supply L in the branch pipe 22 is resolved, allowing for normal use.

[0078] Therefore, in the configuration of the branch pipe water-stopping device 51 shown in the second embodiment, the refrigerant coil 59 is wrapped multiple times around the outer surface 22a of the branch pipe 22 and the refrigerant 45 is flowed through the refrigerant coil 59, rather than directly into the cooling space 57. As a result, even if liquid nitrogen is used as the refrigerant 45, nitrogen gas will not inadvertently leak from the inside of the cooling space 57 into the pit 20. This reliably prevents the pit 20 from becoming filled with gas and causing problems due to oxygen deficiency. Furthermore, since the inner surface of the through-hole 34 of the container 52 is in close contact with the outer surface 22a of the branch pipe 22, and the cooling space 57 formed by the inner surface of the container 52 and the outer surface 22a of the branch pipe 22 is sealed, the inside of the cooling space 57 is efficiently cooled, which helps to cool the refrigerant coil 59 and efficiently freezes the tap water L contained in the branch pipe 22, enabling safe and easy water-stopping. Furthermore, since the container 32 is divided into two parts, container half 32A and container half 32B, it is easier to attach the container 52 to the outer surface 22a of the branch pipe 22 even when working in a narrow space such as a pit 20, thereby improving work efficiency.

[0079] Furthermore, the present invention can be modified or combined in various ways without departing from the spirit of the invention, and it goes without saying that the present invention extends to such modified or combined forms. [Explanation of symbols]

[0080] 20: Pit 21: Main pipe 22: Branch pipe 22a: Outer surface 31, 51: Branch pipe water-stopping device 32, 46, 52: Container 33, 53, 58: Refrigerant introduction / discharge mechanism 34, 47, 54: Through holes 40, 48, 57: Cooling space 45: Refrigerant 59: Refrigerant coil

Claims

1. A branch pipe water-stopping device for stopping the flow of fluid contained in a branch pipe connected to a main pipe, A container having a through hole approximately in the center, with the branch pipe attached to the branch pipe so that it passes through the through hole, and a cooling space formed between the outer surface of the branch pipe and the container, A refrigerant introduction / discharge mechanism is provided for introducing a refrigerant into the cooling space to cool the inside of the cooling space and for discharging the refrigerant introduced into the cooling space to the outside. Equipped with, A branch pipe water-stopping device characterized by freezing the fluid with the cold heat in the cooling space to stop the water flow.

2. The branch pipe water-stopping device according to claim 1, characterized in that the container is configured to be divisible into a plurality of parts radially with respect to the through-hole.

3. The branch pipe water-stopping device according to claim 2, characterized in that the container has a sealant applied to the abutting surfaces that face each other when the container halves, which are divided into multiple parts, are combined.

4. The branch pipe water-stopping device according to claim 1, wherein the container is made of an insulating material.

5. The branch pipe water-stopping device according to claim 1, wherein the container comprises an inner layer made of an insulating material and an outer layer made of a metal material that houses the inner layer.

6. The branch pipe water shutoff device according to claim 1, characterized in that the refrigerant introduction / discharge mechanism comprises a pipe-shaped refrigerant coil having a coil body portion disposed within the cooling space and winding around the outer surface of the branch pipe, a refrigerant introduction side pipe portion connected to the refrigerant introduction side at one end of the coil body portion, and a refrigerant discharge side pipe portion connected to the refrigerant discharge side at the other end of the coil body portion.

7. A branch pipe water-stopping method for stopping water flow in branch pipes connected to a main pipe, A cooling space formation step involves passing the branch pipe through a through hole provided approximately in the center of the container, attaching the container to the outer surface of the branch pipe, and forming a cooling space between the inner surface of the container and the outer surface of the branch pipe to cool the outer surface of the branch pipe. A water shut-off step is performed to introduce a refrigerant into the cooling space to cool the inside of the cooling space, and to discharge the refrigerant introduced into the cooling space to the outside. A branch pipe watertight construction method characterized by including the following:

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