Flow path switching method using a flow control device

Abstract

To provide a flow control method using a flow control device that allows for the attachment and detachment of a control fluid while maintaining an appropriate fluid pressure environment inside the enclosure. [Solution] A flow control device 1A is used to switch a flow path, comprising a housing 3 that is sealed and fitted onto a fluid pipe 2 constituting a flow path, a control fluid 4 that is detachably installed inside the housing 3 and blocks the flow path, and storage sections 50, 90a that can accommodate the control fluid 4 removed from the housing 3. The method involves sealing the housing 3 onto the fluid pipe 2, cutting the fluid pipe 2 inside the housing 3, and installing the control fluid 4 inside the housing 3 to block the flow path, making the primary and secondary sides of the blocked flow path connected by the control fluid 4 to equalize the pressure, making the inside of the housing 3 and the storage sections 50, 90a the same pressure, and then removing the control fluid 4 from the housing 3 to open the flow path.

Description

Technical Field

[0001] The present invention relates to a flow control device composed of a housing externally fitted in a fluid-tight manner to a fluid pipe constituting a flow path, and a fluid control body detachably installed in the housing to block the flow path, and a flow path switching method using the same.

Background Art

[0002] Conventionally, by installing a fluid control body in a housing externally fitted to a fluid pipe constituting a flow path, the flow path is temporarily blocked to form a new flow path, and appropriate work is carried out. After the completion of this work, the pressure inside the housing is made the same, and the flow path inside the housing is restored (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in Patent Document ˙1, since the communication path communicating the flow paths in the housing blocked by the fluid control body extends in the vertical direction, a differential pressure due to the head pressure occurs in the communication path, and the differential pressure is not eliminated in the housing blocked by the fluid control body, and there is a problem that the fluid control body may not be properly attached to and detached from the housing.

[0005] The present invention has been made paying attention to such problems, and an object thereof is to provide a flow control device capable of attaching and detaching a fluid control body in an environment of an appropriate fluid pressure in the housing, and a flow path switching method using the same.

Means for Solving the Problems

[0006] In order to solve the above problems, the flow control device of the present invention A flow control device comprising a housing that is sealed and fitted onto a fluid pipe constituting a flow path, and a control fluid that is detachably installed inside the housing and blocks the flow path, The housing comprises at least a pair of openings that are positioned to sandwich the control fluid, and a connecting pipe section that forms a connecting passage that can be opened and closed between the pair of openings, characterized in that the pair of openings are located at approximately the same height. According to this feature, by opening a pair of openings located at approximately the same height within the housing where the flow path is blocked by the control fluid, the fluid communicates through the connecting pipe. As a result, no pressure difference in hydrohead pressure occurs within the housing surrounding the control fluid, and the control fluid can be attached and detached while maintaining an appropriate fluid pressure environment within the housing.

[0007] The aforementioned connecting pipe section is characterized by comprising at least a horizontal pipe section extending in a substantially horizontal direction. This feature allows for the stabilization of the fluid's movement through the connecting pipe.

[0008] The horizontal pipe section is characterized by being provided with an on / off valve for opening and closing the communication passage. This feature allows the connecting passage to be opened and closed properly without being affected by hydrostatic pressure.

[0009] The connecting pipe section is further characterized by comprising a pair of vertical pipe sections interposed between the pair of openings and the horizontal pipe section, and extending substantially vertically. This feature allows for greater flexibility in setting the height of the horizontal pipe section by interposing a vertical pipe section between a pair of openings and a horizontal pipe section.

[0010] The pair of openings are characterized by being located at the bottom of the housing. This feature makes it possible to avoid an increase in the planar shape of the enclosure.

[0011] The device is characterized by having a storage section capable of accommodating the control fluid removed from the housing, and a branching passage connecting the storage section and the communication passage. This feature allows the pressure inside the containment section to be approximately the same as that of the communication passage, enabling the control fluid to be removed in a more stable state.

[0012] The aforementioned housing is characterized by having an air vent section. This feature allows for filling the pipe with fluid while simultaneously removing air from within the enclosure.

[0013] The device is characterized by sealing the housing over the fluid pipe, cutting the fluid pipe inside the housing, and installing the control fluid to block the flow path. This feature allows the flow path to be shut off while maintaining an environment with appropriate fluid pressure.

[0014] The method is characterized by opening the flow path by removing the control fluid from the housing after blocking the flow path. This feature allows the flow path to be opened while maintaining an environment with appropriate fluid pressure. [Brief explanation of the drawing]

[0015] [Figure 1] (a) is a schematic plan view showing the planned installation location of the flow meter equipment in the existing fluid pipe, (b) is a schematic plan view showing the state in which the flow path has been switched by installing a bypass pipe via a flow control device and branch housing as Example 1 in the existing fluid pipe, and (c) is a schematic plan view showing the state in which the flow meter equipment has been installed at the planned installation location. [Figure 2] (d) is a schematic plan view showing the state in which the primary and secondary sides of the plug in the housing are at the same pressure, and (e) is a schematic plan view showing the state in which the plug has been removed from the housing. [Figure 3] (a) is a partially broken rear view showing the process of cutting the fluid pipe by the cutting device, and (b) is a partially broken rear view showing the area around the drain port of the housing. [Figure 4]It is a partially broken rear view showing the plug insertion process by the insertion device. [Figure 5] It is a partially broken rear view showing a state in which fluid is being discharged from the drain port on the secondary side of the plug in the housing. [Figure 6] (a) is a partially broken rear view showing a state where the primary side and the secondary side of the plug in the housing are at substantially the same pressure, and (b) is an enlarged side view of the main part showing the lower part of the housing and the communication pipe part. [Figure 7] It is a partially broken plan view showing the fluid communication state in the housing and the communication pipe part. [Figure 8] (a) is a rear view of the lower part of the housing showing the drain port, and (b) is an enlarged cross-sectional view showing the housing, the drain port, and the drain pipe. [Figure 9] It is a partially broken rear view showing a state in which the plug is recovered from the housing by the insertion device. [Figure 10] It is a partially broken rear view showing the middle cover insertion process by the insertion device. [Figure 11] (a) is a partially broken plan view showing a state where a flange cover is attached to the drain valve, and (b) is a partially broken rear view showing a state where the upper opening of the housing is closed by the middle cover and the main body cover. [Figure 12] (a) is a schematic plan view showing a state where an existing valve is installed in an existing fluid pipe, (b) is a schematic plan view showing a state where a bypass pipe is newly installed through a flow control device as Example 2 in the existing fluid pipe to switch the flow path, and (c) is a schematic plan view showing a state where the existing valve is removed. [Figure 13] (d) is a schematic plan view showing a state where the primary side and the secondary side of the plug are at the same pressure through the communication pipe part provided in the housing, and (e) is a schematic plan view showing a state where the plug is removed from the housing. [Figure 14] It is a partially broken front view showing the fluid pipe cutting process by the cutting device. [Figure 15] It is a partially broken front view showing the plug insertion process by the insertion device. [Figure 16] It is a partially broken front view showing a state in which fluid is being discharged from the drain port on the secondary side of the housing. [Figure 17](a) is a partially cutaway front view showing the primary and secondary sides of the plug in the housing at approximately the same pressure, and (b) is an enlarged side view of the main parts showing the lower part of the housing and the connecting pipe section. [Figure 18] This is a partially cutaway plan view showing the fluid communication state in the housing and connecting pipe section. [Figure 19] This is a partially broken front view showing the plug retrieved from the housing by the insertion device. [Figure 20] This is a partially broken front view showing the process of inserting the inner lid using an insertion device. [Figure 21] (a) is a partially broken plan view showing the drain valve with the flange cover attached, and (b) is a partially broken front view showing the upper opening of the housing closed with the inner cover and the main cover. [Example 1]

[0016] A flow control device according to Embodiment 1 of the present invention will be described with reference to Figures 1 to 11. In the following description, the lower side of Figure 1 will be described as the front of the flow control device, the upper side as the rear, the left side as the left, and the right side as the right. In addition, the white arrows in Figures 1 and 2 indicate the direction of fluid flow in the pipe, and the halftone areas indicate areas where the fluid is concentrated.

[0017] This first embodiment describes a flow control device as an embodiment of the present invention used in the process of installing flow meter equipment in an uninterrupted flow state at the planned installation location of an existing flow path. Specifically, based on Figures 1(a) to 2(e), the process of installing new flow meter equipment, from installing a bypass pipe to temporarily block the existing flow path, to installing the flow meter equipment, and then opening the existing flow path and removing the bypass pipe, will be described. Details of each step will be explained with reference to Figures 3 to 11.

[0018] In this embodiment, the fluid in the fluid pipe 2 is tap water, but it may also be industrial water, agricultural water, sewage, or other liquids, or even gas or a gas-liquid mixture. The fluid pipe 2 is a ductile cast iron pipe and is formed as a straight pipe with a substantially circular cross-section. In this embodiment, the fluid pipe 2 is arranged in a substantially horizontal direction. The fluid pipe according to the present invention may also be made of other metals such as cast iron or steel, or concrete, polyvinyl chloride, polyethylene, or polyolefin. Furthermore, the inner circumferential surface of the fluid pipe may be covered with an epoxy resin layer, mortar, plating, or a suitable material may be applied to the inner circumferential surface of the fluid pipe by powder coating.

[0019] [Installation process for new flow meter equipment] First, as shown in Figure 1(a), the planned installation location P1 for the flow meter equipment 100 (see Figure 1(c)) is set at a predetermined location in the existing fluid pipe 2. Next, as shown in Figure 1(b), branch pipe housings 30A and 30B are fitted in a sealed manner onto the primary (upstream) and secondary (downstream) sides of the planned installation location P1 in the fluid pipe 2, and these branch pipe housings 30A and 30B are connected to each other by a bypass pipe 9 via on / off valves 37A and 37B. Then, the fluid pipe 2 inside the branch pipe housings 30A and 30B is cut in a continuous flow state using a cutting device 70 (see Figure 3(a)), allowing the fluid to flow from the fluid pipe 2 to the bypass pipe 9. Note that the fluid pipe 2 cutting process is substantially the same as the fluid pipe 2 cutting process performed when installing the flow control devices 1A and 1B described later, so a detailed explanation is omitted here.

[0020] Next, the housings 3, 3 of the flow control devices 1A and 1B, as Embodiment 1 of the present invention, are fitted in a sealed manner onto the primary and secondary sides of the planned installation location P1 between the branch pipe housings 30A and 30B in the fluid pipe 2. Since the flow control devices 1A and 1B are configured similarly, the upstream flow control device 1A will be described below, and the description of the flow control device 1B will be omitted.

[0021] As shown in Figure 3(a), the housing 3 is made of steel and mainly consists of a main body 5 formed in a cylindrical shape with an open top, side body parts 6, 6 formed in a cylindrical shape that protrudes from the left and right sides of the peripheral wall of the main body 5 in a left-right direction substantially perpendicular to the central axis of the main body 5 that faces in the vertical direction and can cover the fluid pipe 2, and a bottom part 7 that closes the lower opening of the main body 5.

[0022] The housing 3 has a split structure that divides it into two parts vertically along the central axis of the side body sections 6, 6, forming a split T-shaped tube consisting of an upper housing 3a and a lower housing 3b. Specifically, the lower housing 3b is formed in a roughly T-shape when viewed from the front by integrally shaping the lower parts of the main body section 5 and the lower parts of the side body sections 6, 6, and is capable of covering the lower part of the fluid pipe 2. The upper housing 3a is formed in a roughly inverted T-shape when viewed from the front by integrally shaping the upper parts of the main body section 5 and the upper parts of the side body sections 6, 6, and is capable of covering the upper part of the fluid pipe 2. Then, by welding these lower housing 3b and upper housing 3a together, they are attached in a sealed manner so as to cover a predetermined portion of the fluid pipe 2 from above and below.

[0023] The axial ends of the side body sections 6, 6 are fitted in a sealed manner, and the housing 3 is fixed to the fluid pipe 2 by the thrust rings 10, 10. Air vent plugs 15 are provided on the upper part of the side body sections 6, 6, and an air vent plug 16 is provided on the upper part of the main body section 5. In addition, bolts 17 for centering the fluid pipe 2 are provided at appropriate locations, such as the lower part of the side body sections 6, 6.

[0024] As shown in Figure 3(a), a steel seat portion 8 is provided protruding from the inner surface of the housing 3 to receive a plug 4, which serves as a fluid regulator, inserted through the top opening of the housing 3. The seat portion 8 consists of a horizontal seat portion 8a (see Figure 3(b)) protruding from the upper surface of the circular bottom portion 7 of the housing 3 in plan view, a vertical seat portion 8b (see Figure 3(b)) extending upward from the front and rear ends of the horizontal seat portion 8a and protruding from the inner surface of the main body portion 5, and an upper seat portion 8c extending circumferentially from the upper end of the vertical seat portion 8b.

[0025] Furthermore, as shown in Figure 3(b), drain ports 13a and 13b are formed through the primary and secondary sides of the transverse seat portion 8a at the lower part of the peripheral wall of the main body 5, sandwiching it in the direction of the pipe axis. A drain pipe 31a with a drain valve 32a (see Figure 7(a)) is connected to the primary drain port 13a, and a drain pipe 31b with a drain valve 32b (see Figure 7(a)) is connected to the secondary drain port 13b. By opening the drain valves 32a and 32b, metal shavings and other debris inside the main body 5 can be discharged along with the fluid inside the pipe. Details of the drain ports 13a and 13b will be described later.

[0026] As shown in Figure 3(a), the upper surface of the main body 5 is open, and a flange 3e projecting outward in the radial direction is formed around the periphery of the opening. In addition, multiple cylindrical portions 27 projecting outward in the radial direction are formed circumferentially at a position above the upper seat portion 8c on the lower outer surface of the main body 5. A screw hole is formed inside each cylindrical portion 27, and a fixing pin 28 is screwed into the screw hole in a radially sealed manner. The fixing pin 28 can be rotated around its axis from the outside of the cylindrical portion 27 using a tool or the like, thereby retracting the tip of the fixing pin 28 into the cylindrical portion 27, allowing the plug 4 to be inserted, or the tip of the fixing pin 28 can be projected into the main body 5 and brought into contact with the upper surface of the lid portion 42, thereby fixing the plug 4 (see Figure 5). The tip of the fixing pin 28 is tapered toward the inner diameter.

[0027] Next, the process of cutting the fluid pipe 2 will be described. First, as shown in Figure 3(a), the side body portions 6, 6 are attached in a sealed manner along the pipe axis of the fluid pipe 2, and a predetermined portion of the fluid pipe 2 is covered in a sealed manner by the housing 3. Then, the gate valve device 50 is connected in a sealed manner to the upper end opening of the main body portion 5. The gate valve device 50 has a cylindrical valve body 50a that penetrates in the vertical direction, a valve cover (not shown) formed to protrude rearward from the valve body 50a and connected to the valve body 50a via a communication port (not shown) formed on its inner circumferential surface, a valve element 50c provided to be movable in a substantially horizontal direction between the valve body 50a and the valve cover (not shown), and a seat portion (not shown) that serves as a valve seat for receiving the valve element 50c. The sealing member (not shown) of the valve element 50c can be in close contact with the seat portion (not shown).

[0028] The valve body 50a is sealed to the upper opening end (opening) of the main body 5 via a sealing member (not shown). The end of a valve stem (not shown), which is screwed with the valve body 50c inside the valve cover, protrudes from the tip of the valve cover. By rotating an operating handle (not shown) attached to the end of this valve stem, the valve body 50c is moved between the valve body 50a and the valve cover, allowing the inside of the housing 3 to be opened and closed.

[0029] Next, the cutting device 70 is sealed and connected to the upper opening end of the valve body 50a. The cutting device 70 mainly consists of a mounting flange cylinder 71, a cutter 72 for cutting the fluid pipe 2, a drive motor 74 for rotating the cutter 72 inside the mounting flange cylinder 71, and a retraction mechanism 73 for moving the cutter 72 up and down. The cutter 72 is formed in a cylindrical shape with an outer diameter larger than the outer diameter of the fluid pipe 2 and consists of a hole saw 72a with a cutting blade along the circumferential direction at its lower end, and a center drill 72b which is arranged coaxially with the rotation axis of the hole saw 72a and protrudes ahead of the cutting blade.

[0030] Furthermore, the cutter 72 is positioned such that the central axis of the center drill 72b is concentric with the central axis of the main body 5 of the housing 3, and is inserted into the main body 5 from the upper open end, and can advance to a position where it penetrates at least the wall of the fluid pipe 2.

[0031] Next, the valve body 50c of the gate valve device 50 is moved toward the valve cover (not shown) to open the inside of the housing 3, and the cutter 72 is rotated around the rotation axis by the drive motor 74 of the cutting device 70, and the cutter 72 is advanced downward by the reciprocating mechanism 73 to cut the fluid pipe 2 in a continuous flow state. When the fluid pipe 2 is cut by the cutter 72, the severed piece (not shown) separated from the ends 2H, 2T (see Figure 4) of the fluid pipe 2 is held inside the hole saw 72a, and the reciprocating mechanism 73 pulls the cutter 72 together with the piece (not shown) into the mounting flange cylinder 71, moving the valve body 50c of the gate valve device 50 toward the valve body 50a to close the inside of the housing 3.

[0032] Most of the foreign matter such as metal shavings generated by cutting is discharged by water pressure along with the fluid inside the pipe through the drain ports 13a and 13b at the bottom of the housing 3. However, over time, some of it sinks due to gravity and falls to the bottom 7 of the housing 3 and accumulates there. In this case, the foreign matter accumulated at the bottom 7 of the housing 3 is discharged to the outside by removing the mounting flange cylinder 71 from the valve body 50a and removing the cutting device 70, and then attaching a discharge device (not shown) to the valve body 50a.

[0033] Next, a plug installation process is performed in which a plug 4, which serves as a fluid control device, is installed inside the housing 3. As shown in Figure 4, first, with the gate valve device 50 closed, the cylindrical member 90a is sealed and connected to the upper side of the valve body 50a. Next, the air vent plug 16 formed above the upper seat portion 8c of the main body portion 5 of the housing 3 and the drain plug (not shown) formed at the lower part of the cylindrical member 90a are connected by a connecting pipe (not shown) to connect the inside of the housing 3 and the inside of the cylindrical member 90a. Fluid is then filled into the cylindrical member 90a while removing air from the air vent valve (not shown) provided at the top of the cylindrical member 90a. After applying water pressure to the cylindrical member 90a that is approximately the same as the pressure inside the fluid pipe 2 to check for leaks, the air vent valve (not shown) is closed after confirming that the air has been removed from the cylindrical member 90a. Next, with the pressure inside the housing 3 and the inside of the cylindrical member 90a approximately equal, the valve body 50c is opened, and the drive mechanism 90b of the insertion device 90 is operated to lower the plug 4.

[0034] The plug 4 mainly comprises a plate-shaped partition wall 41 positioned to partition the pipe axis direction within the main body 5, a disc-shaped cover 42 fixed substantially horizontally to the upper part of the partition wall 41 and closing the upper opening of the main body 5, and a packing 43 extending across the lower end surface, side end surface of the partition wall 41 and the circumferential end surface of the cover 42.

[0035] Once the plug 4 has entered the interior of the housing 3, the packing 43 is pressed against the seat 8 and the plug 4 is set in place. At the same time, the upper opening of the housing 3 is sealed by the lid 42, and the partition wall 41 separates the ends 2H and 2T of the fluid pipe 2 inside the housing 3, preventing water from entering. This separates the fluid into the primary and secondary sides of the plug 4 (see Figure 5). After the plug 4 is set in place, the multiple fixing pins 28, which are arranged circumferentially around the main body 5, are advanced toward the inner diameter side of the main body 5 and brought into contact with the outer surface of the lid 42 (see Figure 5). As a result, the lid 42 is locked to the fixing pins 28, restricting its upward movement and holding it in place in the predetermined position, thus preventing the plug 4 from detaching from the housing 3.

[0036] Next, the drain plug (not shown) located at the bottom of the cylindrical member 90a is opened, and it is confirmed that the packing 43 of the plug 4 is able to stop the water flow. Then, the insertion device 90 and the gate valve device 50 are removed from the housing 3. Subsequently, as shown in Figure 5, the main body cover 30 is placed on top of the housing 3 from above the cover portion 42, and the flange 3e of the main body portion 5 and the main body cover 30 are fastened together with a plurality of fastening members 95 consisting of bolts and nuts to create a sealed connection, thereby completing the installation of the plug 4.

[0037] As shown in Figure 1(b), when the flow path of the bypass pipe 9 is open and the plugs 4 are installed at the left and right flow control devices 1A and 1B, the water flow between the flow control devices 1A and 1B in the fluid pipe 2 is cut off, and the flow path is switched to the bypass pipe 9 via the branch pipe housings 30A and 30B.

[0038] After switching the flow path to the bypass pipe 9, the drain valve 32b of the drain pipe 31b, which is connected to the drain port 13b on the secondary side of the plug 4 inside the housing 3 of the flow control device 1A, is opened, and as shown in Figure 5, the fluid inside the housing 3 is discharged to the outside through the drain port 13b, the drain pipe 31b, and the drain valve 32b.

[0039] As shown in Figure 1(b), the planned installation location P1 side of the flow control devices 1A and 1B is the secondary side. Therefore, for flow control device 1A, the drain valve 32b on the secondary side of plug 4 (left side in the figure) is opened to discharge fluid to the outside from the drain port 13b, while for flow control device 1B, the drain valve 32a on the secondary side of plug 4 (right side in the figure) is opened to discharge fluid to the outside from the drain port 13a.

[0040] After the fluid in the fluid pipe 2 has been discharged between the flow control devices 1A and 1B, the flow meter equipment 100 is installed at the planned installation location P1, as shown in Figure 1(c).

[0041] [Bypass pipe removal process] After the installation of the flow meter equipment 100 is complete, as shown in Figure 2, the plugs 4, 4 of the flow control devices 1A and 1B are removed to release the blockage of the pipeline and restore the flow path at the existing location consisting of the fluid pipe 2. First, before removing the plugs 4, 4, the fluid pressure on the primary and secondary sides of the flow control devices 1A and 1B is made equal. Since the secondary sides of the flow control devices 1A and 1B are in the same connected space, the process of making the fluid pressure on the primary and secondary sides of the flow control device 1A equal will be explained below, and the explanation of the process of making the fluid pressure on the primary and secondary sides of the flow control device 1B equal will be omitted.

[0042] Specifically, as shown in Figures 6(a), (b) and 7, a pair of drain ports 13a and 13b, which are opened so as to sandwich the plug 4 installed inside the housing 3, and a connecting pipe section 35 that can connect the pair of drain ports 13a and 13b, constitute a connecting passage 35a that allows the flow path blocked by the plug 4 to be opened and closed.

[0043] As shown in Figure 8(a), the drain ports 13a and 13b are formed on both sides (left and right) of the vertical seat portion 8b at the lower part of the peripheral wall of the main body portion 5 of the housing 3, opening at approximately the same height. More specifically, the drain ports 13a and 13b are located below the side body portions 6, 6 on the peripheral wall of the main body portion 5 and are formed on one side (rear in this example) in the direction of the fluid pipe 2 in the pipe axis direction. Furthermore, since they are formed at a position where the vertical dimension L1 from the upper surface 7a of the bottom portion 7 of the main body portion 5 of the housing 3 to their respective center positions C, C is the same, their respective center positions C, C are located on the same horizontal plane. In addition, the drain ports 13a and 13b are formed as approximately circular holes, and as shown in Figure 8(b), the lower ends of the drain ports 13a and 13b are positioned slightly below the upper surface 7a of the bottom portion 7. This allows for the efficient discharge of chips and other debris accumulated on the upper surface 7a of the bottom portion 7 during the cutting process described above.

[0044] As shown in Figure 7, the drain pipes 31a and 31b are straight pipes with a roughly circular cross-section that extend rearward from the periphery of the drain ports 13a and 13b on the outer surface of the main body 5, that is, in a roughly horizontal direction perpendicular to the pipe axis of the side body sections 6, 6. The drain valves 32a and 32b are sealed flange-connected to the drain pipes 31a and 31b, and the pipeline can be opened and closed by an operating device (not shown). The connecting pipes 33a and 33b are sealed flange-connected to the drain valves 32a and 32b and consist of curved pipes with a roughly circular cross-section that extend in a roughly horizontal direction. A connecting valve 18 is also provided at the top of the connecting pipe 33a.

[0045] Then, the connecting pipe 33a is sealed by flange connection to the drain valve 32a, and the connecting pipe 33b is sealed by flange connection to the drain valve 32b, and the connecting pipes 33a and 33b are sealed by flange connection to each other. As a result, a connecting pipe section 35 is formed by the drain pipes 31a and 31b, the drain valves 32a and 32b, and the connecting pipes 33a and 33b, which form a roughly U-shape in plan view, and the primary and secondary sides of the plug 4 inside the housing 3 are in communication. Furthermore, as shown in Figures 6(a), (b) and 7, the connecting pipe section 35 has a horizontal pipe section 35b consisting of drain pipes 31a and 31b, drain valves 32a and 32b, and connecting pipes 33a and 33b that extend in a roughly horizontal direction.

[0046] Next, after forming a connecting passage 35a with drain ports 13a, 13b and connecting pipe section 35, the drain valves 32a, 32b are opened, and as shown in Figure 7, the fluid on the primary side of the plug 4 inside the housing 3 flows from drain port 13a into drain pipe 31a, drain valve 32a, and connecting pipe 33a, and then flows from connecting pipe 33b, drain valve 32b, and drain pipe 31b through drain port 13b into the secondary side of the plug 4 and the fluid pipe 2 inside the housing 3 (see Figure 2(d)). Then, while removing air from the air vent plug 15 of the housing 3, the housing 3 and the fluid pipe 2 on the secondary side of the plug 4 are filled with fluid, and after applying water pressure to the secondary side of the plug 4 at approximately the same pressure as the primary side to check for leaks, the air vent plug 15 is closed after confirming that the air in the fluid pipe 2 has been removed.

[0047] Next, as shown in Figures 6(a) and 7, one end of the connecting pipe 19 is connected to the air vent plug 16 provided on the upper part of the main body 5 of the housing 3, and the other end of the connecting pipe 19 is connected to the connecting valve 18 provided on the upper part of the connecting pipe 33a to form a branching passage 19a, thereby connecting the inside of the housing 3, the inside of the gate valve device 50 which serves as the housing, and the inside of the cylindrical member 90a.

[0048] Then, the operating section 18a of the connecting valve 18 (see Figure 7(b)) is opened to supply fluid from the communication passage 35a and the inside of the housing 3 to the cylindrical member 90a, thereby equalizing the pressure inside the gate valve device 50 and the cylindrical member 90a with the inside of the housing 3. Next, as shown in Figure 9, with the inside of the housing 3 and the inside of the cylindrical member 90a at approximately the same pressure, the valve body 50c is opened, and the drive mechanism 90b of the insertion device 90 is operated to raise the plug 4. Once the plug 4 is housed inside the cylindrical member 90a, the valve body 50c is moved into the valve casing 50a to close the inside of the housing 3. This restores the flow path at the existing location consisting of the fluid pipe 2 (see Figure 2(e)).

[0049] In this way, by opening the pair of drain ports 13a and 13b, which are located at approximately the same height within the housing 3 where the flow path is blocked by the plug 4, the fluid communicates through the connecting pipe section 35. As a result, no differential pressure of hydrostatic pressure occurs within the housing 3 surrounding the plug 4, and the plug 4 can be removed while the housing 3 is under an appropriate fluid pressure environment.

[0050] Furthermore, since the connecting pipe section 35 connected to the drain ports 13a and 13b is composed entirely of a horizontal pipe section 35b that is substantially parallel to the pipe axis of the fluid pipe 2, a differential pressure of hydrostatic pressure is less likely to occur inside the housing 3 sandwiching the plug 4.

[0051] Furthermore, since the connecting pipe section 35 protrudes outward from the peripheral wall of the main body section 5 of the housing 3 in the radial direction (rearward in this example), the installation and removal of connecting pipes 33a and 33b, as well as the opening and closing of drain valves 32a and 32b and connecting valve 18 can be performed in a space that does not interfere with the fluid pipe 2, thereby improving work efficiency.

[0052] After housing the plug 4 inside the cylindrical member 90a and closing the valve body 50a with the valve element 50c, the fluid inside the cylindrical member 90a is discharged from a drain plug (not shown) located at the bottom, and the insertion device 90 is removed from the gate valve device 50 to remove the plug 4. Next, the cylindrical member 90a, which houses the inner cover 45 attached to the valve hanger fitting, is sealed and connected to the upper side of the valve body 50a. The air vent plug 16 of the main body 5 of the housing 3 and the drain plug (not shown) at the bottom of the cylindrical member 90a are connected by a connecting pipe (not shown) to connect the inside of the housing 3 and the inside of the cylindrical member 90a. Fluid is then filled into the cylindrical member 90a while venting air from an air vent valve (not shown) located at the top of the cylindrical member 90a. After applying water pressure to the cylindrical member 90a that is approximately the same as the pressure inside the fluid pipe 2 to check for leaks, the air vent valve (not shown) is closed after confirming that the air inside the cylindrical member 90a has been removed.

[0053] Next, as shown in Figure 10, with the pressure inside the housing 3 and the inside of the cylindrical member 90a approximately equal, the valve body 50c inside the valve casing 50a is opened, the drive mechanism 90b of the insertion device 90 is operated to lower the inner cover 45, which is then placed on top of the housing 3 and secured with the fixing pin 28. After securing the inner cover 45, the fluid inside the cylindrical member 90a is drained from the drain plug (not shown) located at the bottom, and the insertion device 90 and the gate valve device 50 are removed from the housing 3.

[0054] Next, as shown in Figure 11(b), the main body cover 30 is placed on top of the housing 3 from above the inner cover 45, and the flange 3e of the main body 5 and the main body cover 30 are fastened together with a plurality of fastening members 95 consisting of bolts and nuts to create a sealed connection, thereby completing the removal process of the plug 4. As shown in Figure 2(e), once the removal of the plugs 4, 4 is completed at the left and right flow control devices 1A, 1B, a flow state is created between the flow control devices 1A, 1B in the fluid pipe 2, and the flow path is switched from the bypass pipe 9 to the fluid pipe 2.

[0055] Finally, as shown in Figure 11(a), the drain valves 32a and 32b are closed, the connecting pipes 33a and 33b are removed from the drain valves 32a and 32b, and flange covers 36a and 36b are attached to the end openings of the drain valves 32a and 32b to complete the work.

[0056] In this embodiment 1, the process of installing a flow metering system 100 in an existing flow path has been described. However, the repair process for repairing an existing flow metering system installed in an existing flow path can be carried out in the same manner as the process of installing the flow metering system 100. Furthermore, the process is not limited to the installation or repair of the flow metering system 100; it may also involve other devices or equipment such as valves, or the installation or repair of fluid pipes. [Example 2]

[0057] Next, the flow control device according to Embodiment 2 of the present invention will be described with reference to Figures 12 to 21. In the following, the differences from Embodiment 1 will be mainly described, and for components and parts that are the same as those in Embodiment 1, the same reference numerals or the same reference numerals plus "200" will be used, and detailed explanations will be omitted.

[0058] This second embodiment describes a flow control device as an embodiment of the present invention used in the process of moving a predetermined section of piping in an existing flow path to another space in an uninterrupted flow state due to occupation or other reasons. Specifically, based on Figures 12(a) to 13(e), the pipeline renewal process from installing a new bypass pipe to block the existing flow path, to removing the predetermined section of piping and making the bypass pipe the permanent piping will be described. Details of each process will be explained with reference to Figures 14 to 21.

[0059] [Pipeline replacement process involving relocating permanent piping] As shown in Figure 12(a), in order to relocate the valve 201 installed in the existing fluid pipe 2 to another space, a predetermined section including the valve 201 is designated as a removal section. Next, as shown in Figure 12(b), the housings 203 and 203 constituting the flow control devices 201A and 201B are fitted in a sealed manner onto the primary side (upstream side) and secondary side (downstream side) of the valve 201 in the fluid pipe 2, and these housings 203 and 203 are connected to each other by a bypass pipe 209. Since the flow control devices 201A and 201B are configured similarly, the upstream flow control device 201A will be described below, and the description of the downstream flow control device 201B will be omitted.

[0060] As shown in Figure 14, the housing 203 is made of steel and mainly consists of a main body 205 formed in a cylindrical shape with an open top, side body 206, 206 formed in a cylindrical shape that protrudes from the left and right sides of the peripheral wall of the main body 205 in a left-right direction substantially perpendicular to the central axis of the main body 205 that oriented in the vertical direction and is capable of covering the fluid pipe 2, a front body 214 that protrudes from the front side of the peripheral wall of the main body 205 in a forward direction substantially perpendicular to the central axis of the main body 205 that oriented in the vertical direction, and a bottom 207 that closes the lower opening of the main body 205.

[0061] The housing 203 has a split structure that divides it into two parts vertically as a split T-tube, consisting of an upper housing 203a and a lower housing 203b along the central axis of the side body sections 206, 206 and the front body section 214. Specifically, the lower housing 203b is formed in a roughly T-shape when viewed from the front by integrally shaping the lower parts of the main body section 205, the side body sections 206, 206 and the front body section 214, and is capable of covering the lower part of the fluid pipe 2. The upper housing 203a is formed in a roughly inverted T-shape when viewed from the front by integrally shaping the upper parts of the main body section 205, the side body sections 206, 206 and the front body section 214, and is capable of covering the upper part of the fluid pipe 2. Then, by welding these lower housing 203b and upper housing 203a together, they are attached in a sealed manner so as to cover a predetermined portion of the fluid pipe 2 from above and below.

[0062] The axial ends of the side sections 206, 206 are fitted in a sealed manner, and the housing 203 is fixed to the fluid pipe 2 by thrust rings 10, 10. An air vent plug 15 is provided on the upper part of the downstream side section 206, and an air vent plug 16 is provided on the upper part of the main section 205. Bolts 17 for centering the fluid pipe 2 are also provided at appropriate locations, such as the lower part of the downstream side section 206. The axial end of the front section 214 is fitted in a sealed manner, and the housing 203 is fixed to the bypass pipe 209 by thrust rings (not shown).

[0063] As shown in Figure 14, a steel seat portion 208 is provided protruding from the inner surface of the housing 203 to receive a plug 204, which is inserted as a fluid control device, through the top opening of the housing 203. The seat portion 208 consists of a horizontal seat portion 208a protruding from the upper surface of the circular bottom portion 207 of the housing 203 in plan view, a vertical seat portion 208b (see Figure 18) extending upward from the front and rear ends of the horizontal seat portion 208a and protruding from the inner surface of the main body portion 205, and an upper seat portion 208c extending circumferentially from the upper end of the vertical seat portion 208b.

[0064] More specifically, as shown in Figure 18, the lateral seat portion 208a of the seat portion 208 extends radially from the right front to the left rear in a plan view, dividing the interior of the main body portion 205 into a primary side and a secondary side of the flow path, and is formed in a substantially curved shape in a plan view. The front end of the lateral seat portion 208a and the longitudinal seat portion 208b extending upward from the front end are arranged between the secondary side hole 206a and the front side hole 214a in the peripheral wall of the main body portion 205, and the rear end of the lateral seat portion 208a and the longitudinal seat portion 208b extending upward from the rear end are arranged near the primary side hole 206a in the region between the primary side hole 206a and the secondary side hole 206a in the peripheral wall.

[0065] Furthermore, drain ports 213a and 213b are formed at the bottom 207 of the main body 205, straddling the primary and secondary sides with respect to the lateral seat 208a. Drain pipes 234a and 231a, each having a drain valve 232a, are connected to the primary side drain port 213a, and drain pipes 234b and 231b, each having a drain valve 232b, are connected to the secondary side drain port 213b. By opening the drain valves 232a and 232b, drainage and metal shavings from inside the main body 205 can be discharged. Details of drain ports 213a and 213b will be described later.

[0066] In plug 204, the difference from the plug of Embodiment 1 is that the flow path switching surface 241c in the partition wall portion 241 is curved. That is, when the flow path switching surface 241c is installed inside the housing 203, it has a concave curved surface with a recess that curves in the direction of flow of the fluid in the pipe from upstream to downstream. As a result, turbulence in the flow of the fluid flowing down the pipe is less likely to occur, and fluid resistance is less likely to occur. Therefore, the load on plug 204 due to fluid turbulence is small, the sealing performance of plug 204 can be maintained for a long period of time, and fluid pressure loss can be suppressed.

[0067] Next, after connecting the housings 203, 203 with the bypass pipe 209, the fluid pipe 2 inside the housing 203 is cut in a continuous flow state using the cutting device 70, as shown in Figure 14, allowing the fluid to flow from the fluid pipe 2 to the bypass pipe 209. The process of cutting the fluid pipe 2 is substantially the same as the process of cutting the fluid pipe 2 when installing the flow control devices 1A and 1B in Embodiment 1 (see Figure 3), so a detailed explanation is omitted here.

[0068] Next, as shown in Figures 15 and 16, a plug installation process is performed in which a plug 204, which serves as a fluid regulator, is installed inside the housing 203. Note that the plug installation process is substantially the same as the plug installation process performed when installing the fluid regulators 1A and 1B in Embodiment 1 (see Figures 4 and 5), so a detailed explanation is omitted here.

[0069] As shown in Figure 12(b), once the plugs 204, 204 are installed in the left and right flow control devices 201A, 201B, the water flow between the flow control devices 201A, 201B in the fluid pipe 2 is cut off, and the flow path is switched to the bypass pipe 209 via the flow control devices 201A, 201B.

[0070] After switching the flow path to the bypass pipe 209, the drain valve 232b of the drain pipe 231b, which is connected to the drain port 213b on the secondary side from the plug 204 inside the housing 203 of the flow control device 201A, is opened, and as shown in Figure 16, the fluid inside the housing 203 is discharged to the outside through the drain port 213b, drain pipes 234b, 231b, and drain valve 232b.

[0071] As shown in Figure 12(b), in flow control devices 201A and 201B, the valve 201 side is the secondary side. Therefore, flow control device 201A discharges fluid to the outside from the drain port 213b on the secondary side (right side in the figure) of the plug 204, while flow control device 201B discharges fluid to the outside from the drain port 213a on the secondary side (left side in the figure) of the plug 204.

[0072] After the fluid in the fluid pipe 2 between the flow control devices 201A and 201B has been discharged, the pipe 2h in a predetermined section including the valve 201 is cut and removed, as shown in Figure 12(c). Furthermore, as a result of cutting and removing the pipe 2h, the pipe caps 2b, 2b are sealed and fixed to the end openings of the short pipes 2a, 2a, which are part of the fluid pipe 2 remaining in the secondary side body portions 206, 206 of the housings 203, 203 of the flow control devices 201A and 201B, to stop water leakage.

[0073] [Plug removal process] After cutting and removing piping 2h, the plugs 204, 204 of flow control devices 201A and 201B are removed from inside the housing 203. Therefore, before removing the plugs 204, 204, the first step is to equalize the fluid pressure on the primary and secondary sides of flow control devices 201A and 201B. Since the secondary sides of flow control devices 201A and 201B are in the same connected space, the following explanation will focus on equalizing the fluid pressure on the primary and secondary sides of flow control device 201A, while omitting the explanation of equalizing the fluid pressure on the primary and secondary sides of flow control device 201B.

[0074] Specifically, as shown in Figures 17(a), (b) and 18, a pair of drain ports 213a and 213b, which are opened so as to sandwich a plug 204 installed inside the housing 203, and a connecting pipe section 235 that can connect the pair of drain ports 213a and 213b, constitute a communication passage 235a that can open and close the flow path blocked by the plug 204.

[0075] As shown in Figure 16, the drain ports 213a and 213b are located on both sides (left and right) of the lateral base portion 208a at the bottom 207 of the main body portion 205 of the housing 203, and are formed to open at approximately the same height position below the pipe axis of the fluid pipe 2. More specifically, since the drain ports 213a and 213b are formed to open on the flat upper surface 207a of the bottom 207 of the main body portion 205 of the housing 203, each drain port 213a and 213b is located on the same horizontal plane. Furthermore, the drain ports 213a and 213b are formed as approximately circular holes, and because they are formed on the bottom 207, chips and other debris that accumulate on the upper surface 207a of the bottom 207 during the aforementioned cutting process can be evenly collected from the outer periphery of the circular holes of the drain ports 213a and 213b and discharged effectively. Furthermore, since each drain port 213a and 213b is formed along the pipe axis of the fluid pipe 2 in a plan view, chips and other debris that move along with the fluid flowing in the pipe along the pipe axis can be efficiently discharged.

[0076] As shown in Figures 17(a) and (b), the drain pipes 234a and 234b are straight pipes with a roughly circular cross-section that extend downward in a roughly vertical direction from the periphery of each drain port 213a and 213b, which are formed by penetrating the bottom 207. The drain pipes 231a and 231b are curved pipes with a roughly circular cross-section that are sealed flange-connected to the lower ends of the drain pipes 234a and 234b and bend backward, extending in a roughly horizontal direction. As shown in Figures 17(a) and (b) and Figure 18, the drain valves 232a and 232b are sealed flange-connected to the drain pipes 231a and 231b, and the pipeline can be opened and closed by an operating device (not shown). The connecting pipes 233a and 233b are sealed flange-connected to the drain valves 232a and 232b and consist of curved pipes that extend in a roughly horizontal direction. Furthermore, a connecting valve 18 is provided at the top of the connecting pipe 233a.

[0077] Then, the connecting pipe 233a is sealed by flange connection to the drain valve 232a, and the connecting pipe 233b is sealed by flange connection to the drain valve 232b, and the connecting pipes 233a and 233b are sealed by flange connection to each other. As a result, a connecting pipe section 235 is formed by the drain pipes 234a and 234b, the drain pipes 231a and 231b, the drain valves 232a and 232b, and the connecting pipes 233a and 233b, which form a roughly U-shape in plan view, and the primary and secondary sides of the plug 204 inside the housing 203 are connected.

[0078] Furthermore, as shown in Figures 17(a), (b) and 18, the connecting pipe section 235 has a horizontal pipe section 235b consisting of drain pipes 231a, 231b, drain valves 232a, 232b and connecting pipes 233a, 233b that extend substantially horizontally, and a pair of vertical pipe sections 235c interposed between a pair of drain ports 213a, 213b and the horizontal pipe section 235b, and extending substantially vertically. The vertical pipe section 235c is composed of vertical sections formed in front of the drain pipes 234a, 234b and drain pipes 231a, 231b.

[0079] Next, after the drain ports 213a, 213b and the connecting pipe section 235 form a connecting passage 235a, the drain valves 232a, 232b are opened, and as shown in Figure 18, the fluid on the primary side of the plug 204 inside the housing 203 flows from the drain port 213a into the drain pipes 234a, 231a, drain valve 232a, and connecting pipe 233a, and then flows from the connecting pipe 233b, drain valve 232b, and drain pipes 231b, 234b through the drain port 213b into the secondary side of the plug 204 inside the housing 203 and into the short pipe 2a (see Figure 13(d)). Then, while removing air from the air vent plug 15 of the housing 203, fluid is filled into the housing 203 and the short pipe 2a on the secondary side of the plug 204. After applying water pressure to the secondary side of the plug 204 at approximately the same pressure as the primary side to check for leaks, the air vent plug 15 is closed after confirming that the air has been removed from the short pipe 2a.

[0080] Next, as shown in Figures 17(a) and 18, one end of the connecting pipe 19 is connected to the air vent plug 16 provided on the upper part of the main body 205 of the housing 203, and the other end of the connecting pipe 19 is connected to the connecting valve 18 provided on the upper part of the connecting pipe 233a to form a branching passage 19a, thereby connecting the inside of the housing 203, the inside of the gate valve device 50 which serves as the housing, and the inside of the cylindrical member 90a.

[0081] Then, the operating section 18a of the connecting valve 18 (see Figure 17(b)) is opened to supply fluid from the communication passage 235a and the inside of the housing 203 to the cylindrical member 90a, thereby equalizing the pressure inside the gate valve device 50 and the cylindrical member 90a with that inside the housing 203. Next, as shown in Figure 19, with the pressure inside the housing 203 and the inside of the cylindrical member 90a approximately equal, the valve body 50c is opened, and the drive mechanism 90b of the insertion device 90 is operated to raise the plug 204. Once the plug 204 is housed inside the cylindrical member 90a, the valve body 50c is moved into the valve casing 50a to close the inside of the housing 203. This creates a new flow path consisting of the bypass pipe 209 (see Figure 13(e)).

[0082] In this way, within the housing 203 where the flow path is blocked by the plug 204, the fluid communicates through the connecting pipe section 235 by opening the pair of drain ports 213a and 213b which are opened at approximately the same height. As a result, no pressure difference in hydrostatic pressure occurs within the housing 203 on either side of the plug 204, and the plug 204 can be removed while the inside of the housing 203 is under an appropriate fluid pressure environment.

[0083] Furthermore, the connecting pipe section 235 connected to the drain ports 213a and 213b is partially composed of a horizontal pipe section 235b that is substantially parallel to the pipe axis of the fluid pipe 2, which makes it less likely for a differential pressure of hydrostatic pressure to occur inside the housing 203 sandwiching the plug 204.

[0084] Furthermore, the connecting pipe section 235 has drain pipes 231a and 231b that extend to the rear of the housing 203, and a portion of the horizontal pipe section 235b protrudes from below the housing 203 in the outward direction (rearward in this example). This allows for installation and removal of connecting pipes 233a and 233b, as well as opening and closing operations of drain valves 232a and 232b and connecting valve 18, in a space that does not interfere with the fluid pipe 2, thus improving work efficiency.

[0085] After housing the plug 204 inside the cylindrical member 90a and closing the valve body 50a with the valve element 50c, the fluid inside the cylindrical member 90a is discharged from a drain plug (not shown) located at the bottom, and the insertion device 90 is removed from the gate valve device 50 to remove the plug 204. Next, a cylindrical member 90a containing an inner cover 45 attached to a valve hanger is sealed and connected to the upper side of the valve body 50a. The air vent plug 16 of the main body 205 of the housing 203 and the drain plug (not shown) at the bottom of the cylindrical member 90a are connected by a connecting pipe (not shown) to connect the inside of the housing 203 and the inside of the cylindrical member 90a. Fluid is then filled into the cylindrical member 90a while air is vented from an air vent valve (not shown) provided at the top of the cylindrical member 90a. After applying water pressure to the cylindrical member 90a that is approximately the same as the pressure inside the fluid pipe 2 to check for leaks, the air vent valve (not shown) is closed after confirming that the air has been vented from the cylindrical member 90a.

[0086] Next, as shown in Figure 20, with the pressure inside the housing 203 and the inside of the cylindrical member 90a approximately equal, the valve body 50c inside the valve casing 50a is opened, the drive mechanism 90b of the insertion device 90 is operated to lower the inner cover 45, which is then placed on top of the housing 203 and secured with the fixing pin 28. After securing the inner cover 45, the fluid inside the cylindrical member 90a is drained from the drain plug (not shown) located at the bottom, and the insertion device 90 and the gate valve device 50 are removed from the housing 203.

[0087] Next, as shown in Figure 21(b), the main body cover 30 is placed on top of the housing 203 from above the inner cover 45, and the flange 3e of the main body 205 and the main body cover 30 are fastened together with a plurality of fastening members 95 consisting of bolts and nuts to create a sealed connection, thereby completing the removal process of the plug 204. As shown in Figure 13(e), once the removal of plugs 204, 204 is completed in the left and right flow control devices 201A, 201B, the flow path is switched to the bypass pipe 209.

[0088] Finally, as shown in Figure 21(a), the work is completed by closing the drain valves 232a and 232b, removing the connecting pipes 233a and 233b from the drain valves 232a and 232b, and attaching the flange covers 236a and 236b to the end openings of the drain valves 232a and 232b (see Figure 13(e)).

[0089] [Effects / Effects] As described above, the flow control devices 1A and 1B as Embodiment 1 of the present invention consist of a housing 3 that is sealed and fitted onto a fluid pipe 2 constituting a flow path, and a plug 4 that is detachably installed inside the housing 3 and serves as a fluid control device to block the flow path. The housing 3 includes at least a pair of drain ports 13a and 13b that are openings that sandwich the plug 4, and a connecting pipe section 35 that constitutes a connecting passage 35a that allows the pair of drain ports 13a and 13b to communicate with each other in an openable and closable manner, and the pair of drain ports 13a and 13b are opening at approximately the same height (see Figures 6 to 8).

[0090] According to this, by opening the pair of drain ports 13a and 13b, which are located at approximately the same height within the housing 3 where the flow path is blocked by the plug 4, the fluid communicates through the connecting pipe section 35. As a result, no differential pressure of hydrostatic pressure occurs within the housing 3 surrounding the plug 4, and the plug 4 can be attached and detached while maintaining an appropriate fluid pressure environment within the housing 3.

[0091] Furthermore, in the flow control devices 201A and 201B as Embodiment 2 of the present invention, a housing 203 is fitted in a sealed manner onto a fluid pipe 2 that constitutes a flow path, and a plug 204 is detachably installed inside the housing 203 as a fluid control fluid that blocks the flow path. The housing 203 includes at least a pair of drain ports 213a and 213b that open to sandwich the plug 204, and a connecting pipe section 235 that constitutes a connecting passage 235a that allows the pair of drain ports 213a and 213b to communicate with each other in an openable and closable manner, and the pair of drain ports 213a and 213b open at approximately the same height (see Figures 17 and 18).

[0092] According to this, by opening the pair of drain ports 213a and 213b, which are located at approximately the same height within the housing 203 where the flow path is blocked by the plug 204, the fluid communicates through the connecting pipe section 235. As a result, no differential pressure of hydrostatic pressure occurs within the housing 203 surrounding the plug 204, and the plug 204 can be attached and detached while maintaining an appropriate fluid pressure environment within the housing 203.

[0093] Furthermore, by including at least horizontal pipe sections 35b and 235b that extend in a substantially horizontal direction, the movement of fluid passing through the connecting pipe sections 35 and 235 can be stabilized.

[0094] Furthermore, drain valves 32a, 32b, 232a, and 232b are provided in the horizontal pipe sections 35b and 235b as on-off valves for opening and closing the connecting passages 35a and 235a, so that the connecting passages 35a and 235a can be properly opened and closed without being affected by hydrostatic pressure.

[0095] Furthermore, a connecting pipe 19 is provided that forms a branched connecting passage 19a connecting a cylindrical member 90a, which serves as a housing for the plugs 4 and 204 removed from the housings 3 and 203, and the connecting passages 35a and 235a. This allows the pressure inside the cylindrical member 90a to be approximately the same as that inside 35a and 235a, thus enabling the plugs 4 and 204 to be removed in a more stable state.

[0096] Furthermore, since one end of the connecting pipe 19 is connected to the connecting pipes 33b and 233a, which are removed after the plug is installed, the connection hole of the connecting pipe 19 does not remain in the housing 3,203 or the drain pipe, thus suppressing the occurrence of water leakage.

[0097] Furthermore, since the housings 3 and 203 are provided with air vent plugs 15 as air vents, it is possible to fill the pipes with fluid while simultaneously venting air from within the housings 3 and 203.

[0098] Furthermore, the connecting pipe section 235 of Embodiment 2 is further provided with a pair of vertical pipe sections 235c interposed between the pair of drain ports 213a, 213b and the horizontal pipe section 235b, extending substantially vertically, which allows for a high degree of freedom in setting the height position of the horizontal pipe section 235b.

[0099] Furthermore, since the pair of drain ports 213a and 213b in Example 2 open into the bottom 207 of the housing 203, it is possible to avoid an increase in the planar shape of the housing 203.

[0100] Furthermore, by fitting the housings 3 and 203 onto the fluid pipe 2 in a sealed manner, and then cutting the fluid pipe 2 inside the housings 3 and 203 and installing plugs 4 and 204, the flow path can be blocked, thus allowing the flow path to be blocked while maintaining an appropriate fluid pressure environment.

[0101] Furthermore, since the flow path is opened by removing plugs 4 and 204 from housings 3 and 203 after blocking the flow path by installing plugs 4 and 204, the flow path can be opened while maintaining an appropriate fluid pressure environment.

[0102] Although embodiments of the present invention have been described above with reference to the drawings, the specific configurations are not limited to these embodiments, and any changes or additions that do not depart from the spirit of the present invention are also included.

[0103] For example, in the above embodiments 1 and 2, examples of openings were shown in which drain ports 13a and 13b formed in the lower part of the peripheral wall of the housing 3 and drain ports 213a and 213b formed in the bottom 207 of the housing 203 were applied. However, the present invention is not limited to this, and other openings besides drain ports formed in locations other than the lower part or bottom of the housing (for example, holes newly created for air vents or communication passages) may also be used.

[0104] Furthermore, while the above-described embodiments 1 and 2 illustrate a configuration in which the connecting pipes 35 and 235 are formed on the outside of the housing 3,203, the present invention is not limited to this, and may be provided inside the housing.

[0105] Furthermore, while the above-described embodiments 1 and 2 illustrate a configuration in which the connecting pipe sections 35 and 235 have at least horizontal pipe sections 35b and 235b, the present invention is not limited thereto, and the horizontal pipe section is not necessarily required. Also, while the embodiment 2 illustrates a configuration in which the connecting pipe section 235 has a vertical pipe section 235c, the present invention is not limited thereto, and the vertical pipe section is not necessarily required.

[0106] Furthermore, while the above-described embodiments 1 and 2 illustrate a configuration in which the drain valves 32a, 32b and 232a, 232b are provided in the horizontal pipe sections 35b and 235b, the present invention is not limited to this, and they may also be provided in the connecting pipe sections 35 and 235 other than the horizontal pipe sections 35b and 235b.

[0107] Furthermore, while embodiments 1 and 2 illustrate a configuration in which the connecting pipes 35 and 235 are provided at the rear of the housing 3,203, the present invention is not limited to this, and may be provided at a vertically downward position of the housing 3,203 so as not to protrude in the outer diameter direction of the housing 3,203.

[0108] Furthermore, in the above embodiments 1 and 2, the connecting pipe section that constitutes a passage that allows a pair of openings to communicate with each other in an openable and closable manner is exemplified as having drain pipes 31a, 31b, 231a, 231b, drain valves 32a, 32b, 232a, 232b, and connecting pipes 33a, 33b, 233a, 233b. However, the present invention is not limited thereto and may include pipes other than drain pipes and connecting pipes, valves other than drain valves, etc.

[0109] Furthermore, in Embodiment 1, the connecting pipes 33a and 33b, which are part of the connecting pipe section 35, were removed after the plug 4 was removed, and in Embodiment 2, the connecting pipes 233a and 233b, which are part of the connecting pipe section 235, were removed after the plug 204 was removed. However, the present invention is not limited thereto, and it is not necessarily required to remove a part of the connecting pipe section after the control fluid is removed; the entire connecting pipe section may remain.

[0110] Furthermore, in the above-described embodiments 1 and 2, the drain ports 13a, 13b, 213a, and 213b are connected by the connecting pipes 35 and 235, and while air is removed from the air vent plugs 15 of the housings 3 and 203, fluid is filled into the housings 3 and 203 and the fluid pipes 2 and short pipes 2a on the secondary side of the plugs 4 and 204. However, the present invention is not limited thereto, and an air valve (not shown) may be provided at an appropriate location on the housings 3 and 203, or an air valve (not shown) may be provided at a location other than the housings 3 and 203, such as the fluid pipes 2 and short pipes 2a on the secondary side of the plugs 4 and 204, and while air is removed by the air valve, fluid is filled into the secondary side pipes of the fluid control system.

[0111] Furthermore, in the above-described embodiments 1 and 2, a plug 4,204 (stopcock) was used as an example of a control fluid capable of blocking the flow path. However, the present invention is not limited to this, and the control fluid may be anything that can control the flow of fluid, as long as it has the function of blocking the flow path, and may also be a valve body such as a gate valve, switching valve, or butterfly valve that can open and close the flow path.

[0112] Furthermore, while the above-described embodiments 1 and 2 illustrated a configuration in which the housing 3, 203 has a divided structure divided into upper and lower halves, the present invention is not limited thereto, and for example, it may have a divided structure divided into three or more circumferential halves. Also, although the housings 3, 203 were made of steel, they may be made of cast iron. In addition, although the upper housings 3a, 203a and the lower housings 3b, 203b were integrated by welding, they may be integrated by fasteners such as bolts.

[0113] Furthermore, in the above embodiment 2, an example was given in which the front body portion 214 for connecting the bypass pipe 209 in the housing 203 is formed on the peripheral wall of the main body portion 205. However, the present invention is not limited to this, and may also be formed on the bottom portion 207. [Explanation of Symbols]

[0114] 1A, 1B, 201A, 201B flow control device 2, 204 fluid pipe 3,203 cabinets 4. 204 Plug (fluid control) 5,205 Main fuselage section 6,206 Side section of the fuselage 7, 207 bottom 7a, 207a top surface 9, 209 Bypass pipe 13a, 13b, 213a, 213b Drain port (opening) 15, 16 Air bleed plug (air bleed section) 18 connecting valves 19 connecting pipes 19a Branching passageway 30A, 30B Branch Pipe Enclosure 31a, 31b, 231a, 231b Drain pipe 32a, 32b, 232a, 232b Drain valve (on / off valve) 33a,33b, 233a,233b connecting pipe 35, 235 Communication pipe section 35a, 235a communication path 35b, 235b horizontal pipe section 235c Vertical pipe section 50 Gate valve device 70 Cutting device 90 Insertion device (housing section) 90a Cylindrical member 100 Flow meter equipment 201 Valve

Claims

1. A flow control device comprising a housing sealed and fitted onto a fluid pipe constituting a flow path, a control fluid detachably installed inside the housing to block the flow path, and a storage section capable of accommodating the control fluid removed from the housing, wherein the flow path switching method uses a flow control device, The housing comprises at least a pair of openings that are opened to sandwich the control fluid, and a connecting pipe section that forms a connecting passage that can be opened and closed to communicate with the pair of openings, The housing is fitted onto the fluid tube in a sealed manner, the fluid tube inside the housing is cut, and the control fluid is placed inside the housing, thereby blocking the flow path. By connecting the primary and secondary sides of the flow path, which were blocked by the control fluid, through the aforementioned connecting pipe section, the pressure is made equal. The inside of the housing and the housing section are made to be at the same pressure, A method for switching a flow path using a flow control device, characterized by opening the flow path by removing the control fluid from the housing.

2. The flow path switching method using the flow control device according to Claim 1, characterized in that the pair of openings are opened at substantially the same height position.

3. The fluid control unit has a partition wall portion arranged to partition the pipe axis direction of the housing and a lid portion that closes the upper part of the housing. A flow control device switching method using the flow control device according to claim 1, characterized in that the inside of the housing and the housing are made to be at the same pressure by connecting them through a communication passage that connects them across the lid.

4. The flow path switching method using the flow control device according to claim 3, characterized in that one end of the connecting pipe constituting the communication passage is connected to an air vent plug provided on the upper part of the housing.

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