JP2006125552A - Conduit and laying method for conduit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conduit capable of supplying different types of fluids at positions close to each other, enabling the layout thereof at low cost, and desirable from the view point of maintaining ground environment and a laying method for the conduit. <P>SOLUTION: This gas conduit 1 is laid out by burying existing low-pressure pipes PGLa and PGLb and existing medium-pressure pipes PGHa and PGHb within a prescribed length on a same route. Namely, the gas conduit 1 comprises a low-pressure pipe 2 and a medium pressure pipe 3 which is formed in a double pipe part 4. The low-pressure pipe 2 is connected, at its both ends, to the existing low-pressure pipes PGLa and PGLb through branch pipes 5A and 5B, and the medium pipe 3 is connected, at its both ends, to the existing medium pressure pipes PGHa and PHGb through the branch pipes 5A and 5B. Thus, by laying out the low-pressure pipe 2 and the medium-pressure pipe 2 on the same route under the ground, both the low-pressure gas and the medium-pressure gas can be supplied simultaneously and construction cost can be decreased and the ground environment can be maintained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a conduit for transporting different types of fluid and a method for laying the conduit.

  Gas produced at a local gas production plant is pumped at a high pressure through a high-pressure line, depressurized by a local governor (depressurizer), and then pumped at a medium pressure through a medium-pressure line. This medium-pressure gas is supplied to large consumers such as industrial customers and building / district heating / cooling customers. The medium pressure gas is further depressurized by the district governor and is pumped at low pressure through the low pressure line. This low-pressure gas is supplied to small-sized customers such as commercial customers and household customers.

  By the way, conventionally, different types of gas conduits are separately laid on the ground even when their paths are close. For example, when a new medium pressure conduit (medium pressure line) or low pressure conduit (low pressure line) is laid due to the generation of new demand for medium pressure gas or low pressure gas or an increase in demand, etc. Usually, it is laid separately on the ground. However, even if laying is required, excavating the ground over the laying path every time is not reasonable because it takes construction labor and time and is costly and is not preferable from the viewpoint of maintaining the ground environment. It is even more desirable that these problems be improved not only for different types of gas conduits but also for conduits embedded in the ground for transporting non-gas fluids.

  The present invention has been made against the background of the prior art as described above. An object of the present invention is to provide a conduit and conduit laying method that can be installed at a low cost with conduits supplying different types of fluids at positions close to each other, and is desirable from the viewpoint of maintaining the ground environment.

  In order to achieve this object, the present invention is configured as the following conduit.

  That is, according to the first aspect of the present invention, the first existing conduit and the second existing conduit that are laid at different locations on the ground and pump different types of fluid are laid on the ground in the same route for a predetermined length range. An outer conduit having both ends communicating with the first existing conduit and both ends communicating with the second existing conduit and being inserted into the outer conduit so as to form an in-pipe space for fluid pumping in the outer conduit. And a small-diameter inner conduit.

  In the invention according to claim 2, the first existing conduit and the second existing conduit that are laid at different locations on the ground and pump gas at a relatively different pressure are the same in a predetermined length range. A pipe laid on the ground by a path, both ends of which are in communication with the first existing pipe and gas is pumped, and both ends of the pipe are in communication with the second existing pipe and in the pipe of the outer pipe for gas pumping And an inner conduit that is inserted through the outer conduit to pump gas at a relatively higher pressure than the outer conduit.

  According to the first and second aspects of the present invention, since the outer conduit and the inner conduit are provided, different types of fluids supplied by the first existing conduit and the second existing conduit are allowed to have a predetermined length range. Can be supplied simultaneously on the same route in the ground. And it is only the outer conduit that needs to be laid on the ground, and it is only necessary to insert the inner conduit through the outer conduit, so it is possible to reduce costs by reducing construction labor and time. The occupied space in the ground is small and the ground environment can be preserved.

  In particular, according to the second aspect of the present invention, since the pipe material having a slightly lower pressure resistance than the pipe material used under atmospheric pressure conditions can be used as the inner conduit, the cost can be further reduced. For example, when a polyethylene pipe is laid on the ground as a medium pressure gas conduit, a protective plate is buried along the longitudinal direction on the polyethylene pipe so that it will not be accidentally damaged during ground excavation in other construction. Protective measures are required as a safety measure. However, according to the present invention, even in such a case, since the inner conduit for pumping relatively high-pressure gas is in the pipe of the outer conduit, it is not necessary to take such protective measures. For this reason, the cost can be reduced and the ground environment can be preserved.

  According to a third aspect of the present invention, the outer conduit is obtained by cutting the first existing conduit laid on the ground for one side and the other side in the predetermined length range.

  According to the invention described in claim 3, since the outer conduit is obtained by cutting the first existing conduit laid on the ground with respect to one side and the other side in the predetermined length range. Therefore, it is not necessary to lay a new pipe, and the first existing conduit can be effectively used as the outer conduit. In this respect, cost reduction and maintenance of the ground environment can be achieved.

  The invention according to claim 4 is an outer tube connected to the first existing conduit and the outer conduit, an inner tube connected to the second existing conduit and the inner conduit and extending through the outer tube. It has a branch pipe which has.

  According to the fourth aspect of the present invention, different types of fluids can be simultaneously supplied through the same path, and at the end thereof, branched to be securely connected to the existing first conduit and the existing second conduit. .

  The invention according to claim 5 includes a bypass pipe having one end branched to the inner conduit and the other end branched to the outer conduit to supply a relatively high-pressure gas pumped by the inner conduit to the outer conduit. Is.

  The longer the laying length of the inner and outer conduits, the lower the gas pressure pumped by the outer conduit and the lower the transport efficiency. However, according to the fifth aspect of the present invention, the gas pressure in the outer conduit can be increased by supplying relatively high pressure gas flowing through the inner conduit to the outer conduit by the bypass tube, so that the laying length is increased. However, it is possible to prevent a decrease in transport efficiency. In this case, a pressure control device having at least one of the function of blocking the inside of the bypass pipe and the function of regulating the relatively high pressure gas flowing into the bypass pipe is configured to be connected to the bypass pipe. You can also.

  The invention according to claim 6 includes a pressure control device having at least one of a function of blocking the inside of the inner conduit and a function of regulating a relatively high-pressure gas pumped by the inner conduit.

  According to the sixth aspect of the present invention, for example, even when the gas pressure of the outer conduit is abnormally increased due to gas leakage from the inner conduit, the supply is performed by shutting off the inside of the inner conduit by the pressure control device. Since it can be stopped, safety can be ensured. In addition, even if a situation occurs in which the relative pressure difference between the inner conduit and the outer conduit fluctuates with respect to a predetermined appropriate value, the pressure control device regulates the pressure in the inner conduit (for example, reduced pressure), It can be controlled to a predetermined appropriate value.

  In addition to the above-described conduits, the present invention is configured as a conduit laying method as described below in order to achieve the above object.

  That is, according to the seventh aspect of the present invention, the first existing conduit and the second existing conduit that are laid at different locations on the ground and pump different types of fluid are laid on the ground in the same route for a predetermined length range. A conduit laying method comprising: an outer conduit corresponding to the predetermined length range; an inner conduit inserted through the outer conduit; a step of laying the ground; an outer tube and an inner tube; Connecting the outer tube to the first existing conduit and the outer conduit, and connecting the inner tube to the second existing conduit and the inner conduit using a branch pipe that extends through the outer pipe. It is configured as a laying method.

  In the invention according to claim 8, the first existing conduit and the second existing conduit that are laid at different locations on the ground and pump gas at a relatively different pressure are the same in a predetermined length range. A conduit laying method for laying in the ground by a route, an outer conduit corresponding to the predetermined length range, an inner conduit that is inserted into the outer conduit and pumps gas at a relatively higher pressure than the outer conduit; The outer pipe is connected to the first existing pipe and the outer pipe using a branch pipe having a step of laying the ground on the ground, an outer pipe and an inner pipe, and the inner pipe extending through the outer pipe. The conduit laying method includes a step of connecting the inner pipe to the second existing conduit and the inner conduit.

  According to the seventh and eighth aspects of the invention, since it is substantially only the outer conduit that needs to be laid on the ground, the inner conduit only needs to be inserted into the outer conduit. The cost can be reduced by reducing labor and time, and the occupied space in the ground is small and the ground environment can be preserved. Thus, different types of fluid supplied by the first existing conduit and the second existing conduit can be simultaneously supplied by the outer conduit and the inner conduit in the same path in the ground for a predetermined length range. .

  In particular, according to the invention described in claim 8, since the pipe material having a slightly lower pressure resistance than the pipe material used under atmospheric pressure conditions can be used as the inner conduit, further cost reduction is possible. For example, when a polyethylene pipe is laid on the ground as a medium pressure gas conduit, a protective plate is buried along the longitudinal direction on the polyethylene pipe so that it will not be accidentally damaged during ground excavation in other construction. Protective measures are required as a safety measure. However, according to the present invention, even in such a case, since the inner conduit for pumping relatively high-pressure gas is in the pipe of the outer conduit, it is not necessary to take such protective measures. For this reason, the cost can be reduced and the ground environment can be preserved.

  The inventions according to claims 7 and 8 that exhibit the above-described actions and effects are more specifically the invention according to claim 9, that is, after the outer conduit is laid on the ground, the inner conduit is changed to the outer conduit. Configured to be inserted. Further, the invention according to claim 10 is configured to be laid on the ground at the same time with the inner conduit inserted through the outer conduit, and according to the present invention, the outer conduit and the inner conduit can be laid efficiently at a time.

  The inventions according to claims 7 to 10 are further configured to cut out the predetermined length range and lay the outer conduit on the ground. According to an eleventh aspect of the present invention, that is, the outer conduit is laid on the ground in a non-open cut for the predetermined length range by a bendable excavator installed on the ground surface. According to the eleventh aspect of the present invention, since a bendable excavator capable of bending excavation installed on the ground surface is used, a large shaft capable of installing a propulsion device on the start side is drilled or restored. Is unnecessary. Further, the outer conduit can be laid on the ground through an arbitrary laying route by bending excavation according to the ground conditions of other buried pipes and underground structures. Furthermore, since the ground is hardly excavated, it is possible to significantly reduce the cost by shortening the construction period and man-hours compared to the open-cut method, and there is an advantage that the ground environment can be preserved.

  Furthermore, in the invention according to claim 12, which achieves the above object, the first existing conduit and the second existing conduit, which are laid at different locations on the ground and pump gas with a relatively different pressure difference, have a predetermined length. The range is a method of laying a conduit that is laid on the ground through the same route, and each of the grounds on both sides in the predetermined length range is opened to expose and cut the first existing conduit, A step of drawing a small-diameter inner conduit for pumping gas at a relatively higher pressure than the first existing conduit from the open end of the first existing conduit, an outer tube and an inner tube, and the inner tube is a tube of the outer tube Using a branch pipe that penetrates to the outside and extending the outer pipe, the outer pipe is connected to the first existing conduit and the outer conduit, and the inner pipe is connected to the second existing conduit and the inner conduit. Is done.

  According to the twelfth aspect of the present invention, a new outer conduit for accommodating the inner conduit is provided for cutting the first existing conduit on both sides of the predetermined length range and drawing and inserting the inner conduit into the inner conduit. There is no need to prepare or lay the pipe, and the existing conduit can be effectively used as it is, and the construction period can be shortened, the number of man-hours can be reduced, and the cost can be greatly reduced by reducing the number of members. Thus, different types of fluids supplied by the first existing conduit and the second existing conduit are simultaneously supplied through the first existing conduit and the inner conduit in the same path in the ground for a predetermined length range. Can do.

  According to the twelfth aspect of the present invention, it is possible to use, as the inner conduit, a pipe material that has a slightly lower pressure resistance than the pipe material used under atmospheric pressure conditions, so that further cost reduction can be achieved. For example, when a polyethylene pipe is laid on the ground as a medium pressure gas conduit, a protective plate is buried along the longitudinal direction on the polyethylene pipe so that it will not be accidentally damaged during ground excavation in other construction. Protective measures are required as a safety measure. However, according to the present invention, even in such a case, since the inner conduit for pumping relatively high-pressure gas is in the pipe of the outer conduit, it is not necessary to take such protective measures. For this reason, the cost can be reduced and the ground environment can be preserved.

  By the way, in the above-described conduits and conduit laying methods according to the present invention, “different types of fluids” correspond to gases and liquids, and two types of gases and two types of liquids having different compositions are the same in composition. It is a concept that includes two types of gases or two types of liquids that have different supply pressures through a conduit. It is impossible to enumerate all of these, but examples include production gas and natural gas, gas and hydrogen, and the low pressure supplied by the low-pressure line that forms the gas supply pipeline described in the background art at the beginning. The medium pressure gas supplied through the gas and the medium pressure line, the low pressure gas and the intermediate pressure gas, the intermediate pressure gas and the medium pressure gas, and the like can be listed.

  In addition, the “first existing conduit” and the “second existing conduit” in the present invention described above may be those that are laid on the ground when the conduit of the present invention is connected. Accordingly, a conduit newly laid on the ground after the conduit of the present invention is laid on the ground is also included in them. However, the invention according to claim 3 and the invention according to claim 12 refer to an existing conduit already embedded in the ground and used for fluid supply before the conduit of the present invention is laid on the ground.

  According to the conduit and the conduit laying method of the present invention, it is possible to construct conduits for supplying different kinds of fluids in the same path in the ground for a predetermined length range and supply fluids simultaneously. In addition, the construction cost can be surely reduced, and the ground environment can be preserved.

  Hereinafter, an example of an embodiment of a conduit and a conduit laying method according to the present invention will be described with reference to the drawings. In this embodiment, as an example, a gas conduit for simultaneously supplying low-pressure gas and medium-pressure gas and a method for laying the gas conduit will be described.

Embodiment of gas conduit [FIGS. 1 to 3] ; A gas conduit 1 shown as an example in FIG. 1 includes a large-diameter low-pressure pipe 2 as an “outer conduit” and a small-diameter “inner conduit” inserted therethrough. A double pipe portion 4 comprising an intermediate pressure pipe 3 is provided.

  The low-pressure pipe 2 is a conduit that decompresses high-pressure gas delivered from a local gas manufacturing plant in multiple stages by a plurality of governors (decompression devices) and pumps low-pressure gas supplied through a low-pressure line (not shown). The low-pressure pipe 2 includes both existing and new pipes that have already been laid on the ground, and cast iron pipes and steel pipes are used, as will be described in the construction method of the gas conduit 1 described later.

  The medium pressure pipe 3 is a conduit for depressurizing the high pressure gas delivered from a local gas manufacturing plant in multiple stages with a plurality of governors (decompression devices) and pumping the medium pressure gas supplied through a medium pressure line (not shown). is there. As shown in FIG. 2, the outer diameter of the intermediate pressure pipe 3 is smaller than the inner diameter of the low pressure pipe 2 so that the low pressure pipe 2 can be laid while leaving the pressure feed space 2 s in the low pressure pipe 2. As such an intermediate pressure pipe 3, a polyethylene pipe is used.

  The double pipe portion 4 composed of the low pressure pipe 2 and the intermediate pressure pipe 3 as described above is laid on the ground with a length of several meters to several hundred meters. Branch pipes 5 </ b> A and 5 </ b> B are connected to both ends of the double pipe part 4. The branch pipes 5A and 5B include an outer pipe 6 connected to the end of the low-pressure pipe 2 via a socket S, and an inner pipe 7 butt-joined to the intermediate-pressure pipe 3, both of which are made of polyethylene pipes. Is done.

  The outer tube 6 includes a short tube 6a connected to the socket S, a cheese tube 6b, a short tube 6c, a deformed socket 6d, and an extension tube 6e extending in a crank shape from the cheese tube 6b. A branch (flow path) of the outer pipe 6 with respect to the inner pipe 7 is formed by an extension pipe 6e connected to the cheese pipe 6b and the cheese pipe 6b. Further, as shown in FIG. 3, in the tube of the deformed socket 6 d, the inner peripheral surface and the inner surface of the outer tube 6 are maintained so that airtightness is maintained between the tube of the outer tube 6 and the outer peripheral surface of the inner tube 7. A sealing portion 6f formed by heat-sealing the outer peripheral surface of the tube 7 is formed.

  The inner pipe 7 is connected to the end of the intermediate pressure pipe 3, and is connected to the long pipe 7a and a long pipe 7a that extends through the pipe of the outer pipe 6 and extends from the end of the deformed socket 6d to the outside. It is comprised with the extension pipe | tube 7b.

  In the gas conduit 1 as described above, the branch pipe 5A side is the primary side in the gas pumping direction, and the branch pipe 5B side is the secondary side. Therefore, the outer pipe 6 that pumps the low-pressure gas out of the branch pipe 5A on the primary side is the existing low-pressure as the “first existing pipe” that constitutes a part of the pipeline in which the extension pipe 6e supplies gas from the gas manufacturing plant. The low pressure gas GL is supplied by being connected to the pipe PGLa. Further, the inner pipe 7 is connected to an existing intermediate pressure pipe PGHa as a “second existing conduit” in which the extension pipe 7b forms a part of the same pipeline, and supplies the intermediate pressure gas GH.

  Further, in the branch pipe 5B on the secondary side, the extension pipe 6e of the outer pipe 6 is connected to the existing low-pressure pipe PGLb as the “first existing pipe”, and the low-pressure gas is supplied to commercial customers and household customers. Will be. The inner pipe 7 has an extension pipe 7b connected to an existing intermediate pressure pipe PGHb as a “second existing conduit” to supply intermediate pressure gas to industrial consumers, building air conditioning / district air conditioning customers, and the like. Become.

Embodiment of Gas Pipe Laying Method [FIGS. 4 to 9] ; Next, an embodiment of a method of laying the gas pipe 1 on the ground will be described. In this embodiment, an example in which an existing low pressure pipe laid on the ground is used as the low pressure pipe 2 within a predetermined length range and a new intermediate pressure pipe 3 is laid on the low pressure pipe will be described.

  First, as shown in FIG. 4, one side and the other side in the pumping direction of the existing low-pressure pipe 2 are excavated to construct the shafts 12 and 13 on the ground 11. Note that either the one side or the other side may be the primary side or the secondary side.

  Next, as shown in FIG. 5, the existing low-pressure pipes 2 exposed in the shafts 12 and 13 are cut. And the rod 15 is introduced from the end opening 2a of the existing low-pressure pipe 2 using a universal propulsion device 14 capable of bending excavation installed on the ground surface near the shaft 12, and inside the shaft 13 as shown in FIG. To reach. The rod 15 is formed by sequentially connecting and connecting flexible steel pipe unit rods.

  When it reaches, the tip 15a of the rod 15 is removed, and the intermediate pressure pipe 3 to be newly laid is attached. Then, by pulling back the rod 15, the intermediate pressure pipe 3 is laid in the existing low pressure pipe 2 as shown in FIG. 7. At this time, the end opening 2b of the existing low-pressure pipe 2 exposed to the shaft 13 is prevented from being damaged by sliding the intermediate pressure pipe 3 with the end opening 2b, and the introduction of the intermediate pressure pipe 3 is facilitated. Further, a guide roller 16 is attached. Then, the intermediate pressure pipe 3 is laid as shown in FIG.

  When the intermediate pressure pipe 3 is thus laid, the aforementioned branch pipe 5A and branch pipe 5B are connected as shown in FIG. That is, the end of the existing low-pressure pipe 2 in the shafts 12 and 13 is connected to the short pipe 6a of the outer pipe 6 via the socket S1, and the long pipe 7a of the inner pipe 7 is butt-joined to the intermediate pressure pipe 3. The branch pipe 5A and the extension pipe 6e of the outer pipe 6 of the branch pipe 5B are connected to the end openings 2c and 2d of the other existing low-pressure pipe 2, and the extension pipe 7b of the inner pipe 7 is not shown. Connect to the existing intermediate pressure pipe or new intermediate pressure pipe. After this, the shafts 12 and 13 are backfilled and restored.

Next, the operation and effect of the gas conduit 1 and the construction method of the gas conduit 1 according to the above embodiment will be described.

  The gas conduit 1 includes a large-diameter low-pressure pipe 2 and a small-diameter medium-pressure pipe 3 that is laid in the low-pressure pipe 2 while leaving a pumping space 2 s for pumping gas at a low pressure. For this reason, the low-pressure gas GL and the intermediate-pressure gas GH having different pressures, which are different in pressure in this embodiment, can be simultaneously supplied through the same path in the ground 11 for a predetermined length range. . And in this embodiment, the operation | work which prepares a new pipe and lays it in the ground 11 is unnecessary, inserts the intermediate pressure pipe 3 using the existing low pressure pipe 2 as it is, and connects the branch pipes 5A and 5B. Since it is only connected, the cost can be greatly reduced by shortening the work period, reducing the number of man-hours, and reducing the number of members. Further, the occupied space in the ground 11 is small, and the ground environment can be preserved.

  Due to the pressure difference with the low-pressure pipe 2, the intermediate-pressure pipe 3 can use a material and pipe thickness that are slightly inferior to those of a general intermediate pressure pipe used under atmospheric pressure conditions. Therefore, further cost reduction is possible.

  When laying polyethylene pipes on the ground as medium-pressure gas conduits, take protective measures such as burying a protective plate along the longitudinal direction of the polyethylene pipes so that they will not be accidentally damaged during ground excavation in other construction. Applying as a safety measure is required. However, in the above-described embodiment, the intermediate pressure pipe 3 made of a polyethylene pipe is in the pipe of the low pressure pipe 2 made of a cast iron pipe or a steel pipe and is protected against the outside in the ground 11. For this reason, even if it does not take such a protective measure, it will not be damaged by the ground excavation apparatus used for other construction, but a gas will leak. Therefore, since the protective measures are unnecessary, the cost can be reduced and the ground environment can be preserved.

  The gas conduit 1 includes branch pipes 5A and 5B that branch the low pressure pipe 2 and the intermediate pressure pipe 3. For this reason, different types of gas can be transported simultaneously on the same laying route, and at the end thereof, branched by the branch pipes 5A and 5B to the other existing low pressure pipes and existing medium pressure pipes having different laying paths. Can be connected to. And since the outer tube 6 and the inner tube 7 are completely sealed by the sealing part 6f, the gas leakage of the low pressure gas does not occur.

  In the laying method of the gas conduit 1, the intermediate pressure pipe 3 is retracted using the universal propulsion device 14 installed on the ground surface, so that the vertical shaft 12 on the starting side where the universal propulsion device 14 is installed is a propulsion device inside the shaft 12. Compared to the example of installing the, the size can be reduced and the cost can be reduced.

Modified Examples of Embodiments [FIGS. 10 to 14] ; The above-described embodiments can be modified. Examples will be listed and described.

  In the above-described embodiment, low-pressure gas and medium-pressure gas are exemplified as “different types of fluids”, but medium-pressure gas and high-pressure gas, medium-pressure gas and intermediate-pressure gas, intermediate-pressure gas and low-pressure gas, and the like may be used. In the city gas supply line, the gas types with relatively different pressures are generally different within the range of gas pressures generally classified as low pressure gas, intermediate pressure gas, medium pressure gas, and high pressure gas. It may be a fluid. Furthermore, a combination of fluids having different compositions such as gas and hydrogen, or a combination of fluids such as gas and liquid may be used as different types of fluids.

  The length, shape, branching structure, and the like of the gas conduit 1 of the above embodiment are examples. Therefore, these can be appropriately changed according to the construction situation at the site.

  As an example, as shown in FIG. 10, for example, the double pipe portion 4 can be configured to include a bypass pipe 17 having one end branched and connected to the medium pressure pipe 3 and the other end branched to the low pressure pipe 2. . Reference numeral 18 denotes a governor as a pressure control device, which has a function of blocking the inside of the bypass pipe 17 and a function of regulating (for example, reducing pressure) the intermediate pressure gas taken out from the intermediate pressure pipe 3. Note that the governor 18 does not have both of these functions, but may use one having only one of these functions.

  The advantage of such a bypass pipe 17 is as follows. That is, the longer the pipe length of the double pipe section 4, the lower the gas pressure fed by the low pressure pipe 2 and the lower the transport efficiency. However, since the gas pressure of the low-pressure pipe 2 can be increased by supplying the intermediate-pressure gas pumped by the intermediate-pressure pipe 3 to the low-pressure pipe 2 by the bypass pipe 17, the transport efficiency can be improved even if the pipe length of the double pipe portion 4 becomes long. It will be possible to prevent the decrease of.

  In addition, the low pressure pipe 2 and the intermediate pressure pipe 3 of the double pipe portion 4 can of course be configured to include a supply pipe that is branched and connected. This supply pipe supplies gas to a low-pressure consumer or a medium-pressure consumer, and any number of pipes may be branched from the low-pressure pipe 2 or the medium-pressure pipe 3.

  In the above embodiment, as shown in FIG. 3, the airtightness between the inner tube 7 and the outer tube 6 in the branch pipes 5A and 5B is changed between the outer peripheral surface of the long tube 7a of the inner tube 7 and the deformed socket 6d of the outer tube 6. It is obtained by the sealing part 6f formed by heat-sealing the inner peripheral surface of the metal, but instead of sealing by such chemical means, the sealing part is formed by physical means such as a packing material. It may be. Moreover, you may use both of these together.

As shown in FIG. 11, the gas conduit 1 according to the above embodiment is configured to include a governor 19 as a pressure control device, for example, in the extension pipe 7 b of the inner pipe 7 that transports the medium-pressure gas of the branch pipe 5 </ b> A. be able to. The governor 19 has a function of blocking the inside of the intermediate pressure tube 3 and a function of regulating the pressure of the intermediate pressure gas fed by the intermediate pressure tube 3. The governor 19 is connected to one end of a monitoring pressure introduction pipe 19a. The other end of the monitoring pressure introduction pipe 19a is connected to communicate with the inside of the outer pipe 6 (short pipe 6c) of the branch pipe 5A. For this reason, low pressure gas is introduced into the governor 19 and its pressure is monitored.

  Such a governor 19 automatically raises the abnormal pressure of the low-pressure gas introduced from the monitoring pressure introduction pipe 19a when the gas pressure of the low-pressure pipe 2 is abnormally increased due to gas leakage from the intermediate pressure pipe 3, for example. It detects and operates so as to block the inside of the intermediate pressure pipe 3. Thereby, since supply of medium pressure gas can be stopped, safety can be secured. When it is detected that the relative pressure difference between the pressure of the low pressure gas introduced from the monitoring pressure introduction pipe 19a and the medium pressure gas passing through the governor 19 fluctuates with respect to a predetermined appropriate value, the intermediate pressure pipe 3 The pressure inside the tube is regulated (for example, reduced pressure) so that it can be returned to a predetermined appropriate value.

  In addition, although the governor 19 of FIG. 11 provided the function of both the above-mentioned interruption | blocking and pressure regulation, and demonstrated the thing which has the monitoring pressure introduction pipe | tube 19a, it is not restricted to this. That is, it can also be configured as another “pressure control device” having a function of either cutoff or pressure regulation. Further, instead of introducing the low-pressure gas as the reference pressure, the pressure state of the low-pressure gas may be detected by a pressure sensor and electrically transmitted to the governor 19 or other “pressure control device”.

  In the laying method of the gas conduit, an example in which the new intermediate pressure pipe 3 is laid in the pipe of the existing low pressure pipe 2 has been shown, but it can also be implemented as a method of newly laying both the low pressure pipe and the intermediate pressure pipe.

  For example, as shown in FIG. 12, the ground corresponding to the laying route is excavated, a new low pressure pipe 20 and an intermediate pressure pipe 3 are laid there, and a branch pipe 5A, 5B outside the figure is connected. You can also. In this case, since the ground 11 is greatly cut, the cost increases. However, since the individual cuts are not required for the low pressure pipe 20 and the intermediate pressure pipe 3, the range can be reduced even if the ground is cut.

  Moreover, it can also be set as the laying construction method as shown in FIG.13 and FIG.14 using the universal propulsion machine 14 and the rod 15 which can be bent and excavated.

  That is, in this construction method, first, as shown in FIG. 13, the ground 11 is excavated until reaching the vertical shaft 13 to form a pilot hole. Next, the tip 15 a is removed in the shaft 13 to connect the expanded reamer 21, and both the new low pressure pipe 20 and the intermediate pressure pipe 3 are connected to the expanded reamer 21. Then, as shown in FIG. 14, by pulling back the rod 15 with the universal propulsion device 14, both the low pressure pipe 20 and the intermediate pressure pipe 3 are laid simultaneously in a double pipe state.

  According to this laying method, since the universal propulsion device 14 that can be bent and excavated is used, it is not necessary to open and restore a large shaft for propulsion installation on the start side. Moreover, the low pressure pipe 20 and the intermediate pressure pipe 3 can be laid on the ground 11 by an arbitrary laying path by bending excavation according to the ground conditions of other buried pipes and underground structures. Furthermore, compared with the open-cut method with large ground excavation as shown in FIG. 12, it is possible to significantly reduce the cost by shortening the work period and the number of man-hours, and there is an advantage that the ground environment can be maintained. Since both the low pressure pipe 20 and the intermediate pressure pipe 3 are laid at the same time, it can be laid efficiently.

  Further, instead of laying both at the same time as shown in FIG. 14, after laying a new low-pressure pipe 20, a new intermediate-pressure pipe 3 is laid in the pipe of the low-pressure pipe 20 in accordance with the steps in FIG. It can also be a construction method. In the case of this laying method and the laying method according to the above-described embodiment, a traction device is installed on the ground surface or the vertical shaft 12 instead of using an excavating device such as the universal propulsion device 14. The intermediate pressure tube 3 may be retracted with a linear member for retracting such as a wire.

1 is a plan view of a gas conduit according to one embodiment. FIG. The expanded sectional view which shows the double pipe part of FIG. The principal part expanded sectional view which shows the sealing part of the outer tube | pipe of FIG. 1, and an inner tube | pipe. Process explanatory drawing of the laying construction method of the gas conduit by one Embodiment. Process explanatory drawing which pushes the rod for drawing in into the existing low-pressure pipe following FIG. Process explanatory drawing which shows the state which the rod for drawing-in reached the shaft following FIG. Process explanatory drawing which shows the state which draws in an intermediate pressure pipe in the existing low pressure pipe following FIG. Process explanatory drawing which shows the state which pulled in the intermediate pressure pipe following FIG. Process explanatory drawing which shows the state which connected the branch pipe to the low pressure pipe and the intermediate pressure pipe following FIG. Explanatory drawing which shows the modification of a gas conduit typically. Explanatory drawing which shows the other modification of a gas conduit typically. Process explanatory drawing of the construction method of the other gas conduit | pipe by the modification of embodiment. Process explanatory drawing of the construction method of the further another gas conduit | pipe by the modification of embodiment. Process explanatory drawing which shows the state which lays down both a low pressure pipe and an intermediate pressure pipe simultaneously after FIG.

Explanation of symbols

1 Gas conduit 2 Low pressure pipe (outer conduit)
2a, 2b, 2c, 2d End opening 2s Pumping space 3 Medium pressure pipe (inner conduit)
4 Double pipe part 5A Branch pipe 5B Branch pipe 6 Outer pipe 6a Short pipe 6b Cheese pipe 6c Short pipe 6d Deformed socket 6e Extension pipe 6f Sealing part 7 Inner pipe 7a Long pipe 7b Extension pipe 11 Ground 12 Vertical shaft 13 Vertical shaft 14 Freely adjustable Propulsion machine 15 Rod 15a Tip 16 Guide roller 17 Bypass pipe 18 Governor 19 Governor (pressure control device)
19a Monitoring pressure introduction pipe 20 Low pressure pipe (outer conduit)
21 Expanded Reamer S Socket

Claims (12)

A first existing conduit and a second existing conduit that are laid at different locations on the ground and pump different types of fluid, and are laid on the ground in the same path for a predetermined length range,
An outer conduit having both ends communicating with the first existing conduit;
A small-diameter inner conduit having both ends communicating with the second existing conduit and being inserted into the outer conduit so as to form a fluid pumping space within the outer conduit. The first existing conduit and the second existing conduit, which are laid at different locations on the ground and pump gas at relatively different pressures, are laid on the ground in the same route for a predetermined length range. ,
An outer conduit whose ends communicate with the first existing conduit and pump gas;
An inner conduit having both ends communicating with the second existing conduit and inserted into the outer conduit so as to form an in-pipe space for gas feeding in the outer conduit, and pumping gas at a relatively higher pressure than the outer conduit; A conduit comprising.   The conduit according to claim 1 or 2, wherein the outer conduit is obtained by cutting the first existing conduit laid on the ground on one side and the other side in the predetermined length range.   A branch pipe comprising: an outer pipe connected to the first existing pipe and the outer pipe; and an inner pipe connected to the second existing pipe and the inner pipe and extending through the outer pipe. The conduit according to any one of claims 1 to 3.   5. A bypass pipe having a branch connection at one end to the inner conduit and a branch connection at the other end to the outer conduit for supplying a relatively high pressure gas pumped by the inner conduit to the outer conduit. A conduit according to claim 1.   The conduit according to any one of claims 1 to 5, further comprising a pressure control device having at least one of a function of blocking the inside of the inner conduit and a function of regulating a relatively high pressure gas pumped by the inner conduit. . The first existing conduit and the second existing conduit, which are laid at different locations on the ground and pumping different types of fluid, are laid on the ground in the same route for a predetermined length range,
Laying on the ground an outer conduit corresponding to the predetermined length range and an inner conduit inserted through the outer conduit;
A branch pipe having an outer pipe and an inner pipe, the inner pipe extending through the outer pipe and extending, is connected to the first existing conduit and the outer conduit, and the inner tube is connected to the second existing conduit. And a method of laying the conduit, including connecting to the inner conduit. A method for laying a conduit that lays a first existing conduit and a second existing conduit, which are laid at different locations on the ground, with a relatively different pressure, on the ground in the same route for a predetermined length range Because
Laying on the ground an outer conduit corresponding to the predetermined length range, and an inner conduit that passes through the outer conduit and pumps gas at a relatively higher pressure than the outer conduit;
A branch pipe having an outer pipe and an inner pipe, the inner pipe extending through the outer pipe and extending, is connected to the first existing conduit and the outer conduit, and the inner tube is connected to the second existing conduit. And a method of laying the conduit, including connecting to the inner conduit.   The conduit laying method according to claim 7 or 8, wherein the inner conduit is inserted into the outer conduit after the outer conduit is laid on the ground.   The conduit laying method according to claim 7 or 8, wherein the conduit is laid on the ground simultaneously with the inner conduit inserted through the outer conduit.   The conduit laying method according to any one of claims 7 to 10, wherein the outer conduit is laid on the ground in a non-open cut by a universal propulsion device capable of bending excavation installed on the ground surface. A method for laying a conduit that lays a first existing conduit and a second existing conduit, which are laid at different locations on the ground, with a relatively different pressure, on the ground in the same route for a predetermined length range Because
Excavating the ground on both sides in the predetermined length range to expose and cut the first existing conduit; and
Drawing a small-diameter inner conduit that pumps gas at a relatively higher pressure than the first existing conduit from the open end of one first existing conduit;
A branch pipe having an outer pipe and an inner pipe, the inner pipe extending through the outer pipe and extending, is connected to the first existing conduit and the outer conduit, and the inner tube is connected to the second existing conduit. And a method of laying the conduit, including connecting to the inner conduit.

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