Existing pipe slitting method, piping structure, and method for inserting a valve in a line

Abstract: The invention relates to an existing pipe cut-off method and slitting method, by which an existing pipe made of cast iron and steel can be cut off. With a cut-off method according to the invention, first, a part of an existing pipe 1 is enclosed and sealed up by a seal-up housing 2 in an airtight state, a cutting tool 30 having a plurality of blades 30c is accommodated in the corresponding seal-up housing in a state the cutting tool is attached to the abovementioned seal-up housing 2. Next, the cutting tool 30 is fed toward the center of the abovementioned existing pipe 1 while slitting the existing pipe 1 by rotating the cutting tool 30 by power of a prime mover, and the abovementioned existing pipe 1 is cut off by the cutting tool 30 by turning the abovementioned seal-up housing 2 in the circumferential direction R of the existing pipe 1.

Description: The present invention relates to an existing pipe slitting method, and a valve insertion method for inserting a valve in a line without stopping passage of water or fluid, etc. Conventionally, a valve insertion method for inserting a valve in a line without stopping passage of water, by which an existing pipe is cut off without stopping passage of water and a valve is inserted into the cut-off portion of the existing pipe in a line including the existing pipe, has been already publicly known. FIG.26 shows a sketch of a conventional method disclosed in JP-A-44167 (1980), JP-A-83690 (1981), JP-A-120886 (1981), and JP-A-47089 (1982). The method illustrated in the drawing is such that cutting equipment 500 is fixed at an existing pipe 1, the cutting equipment 500 and existing pipe 1 are enclosed and sealed up by a seal-up housing 501, and left and right blades 502 are rotated along the cutting equipment 500 in order to cut off the existing pipe 1. Thereafter, a valve is inserted into a line 1A instead of a cut-off section 10 of the existing pipe 1 by opening and closing an operation sluice valve 503. In the prior art, since the cutting equipment 500 is accommodated in the seal-up housing 501, the seal-up housing 501 is made large-scaled to resultantly expand the digging area, etc. FIG.27 shows a sketch of a prior method disclosed in United States Patent No. 5,611,365 and International Laid-Open WO 97/31207. With the method illustrated in the drawing, an existing pipe 1 is enclosed and sealed up by a seal-up housing 600, a cutting tool 602 is fixed at and attached to the tip end of a gate valve 601 installed at the seal-up housing 600, and the gate valve 601 is turned together with the seal-up housing 600, wherein an existing pipe 1 is cut off by the cutting tool 602. According to the prior arts, since the cutting tool 602 is turned by rotations of the seal-up housing 600, it is not necessary that the seal-up mechanism for turning the cutting tool 602 is provided in a seal-up housing 600. Therefore, the seal-up housing 600 can be small-sized. However, with such conventional cut-off methods, a chip-like cutter 602 bites an existing pipe 1. Therefore, in a housing of cutting into an existing pipe 1 made of cast iron or steel, the seal-up housing 600 must be turned many times, wherein it takes much time to cut off. Furthermore, there is a fear that rubber packing to seal between the seal-up housing 600 and existing pipe 1 is damaged. Fig.28 shows a sketch of a conventional cut-off method disclosed in United States Patent Nos. 3,650,547, 3,703,906, and 3,735,775. With the prior art shown in the drawing, an existing pipe 1 is enclosed and sealed up by a seal-up housing 700, and after a cutting wheel 701 attached to the seal-up housing 700 is caused to bite the existing pipe 1 by a lead screw 702, the cutting wheel 701 is turned together with the seal-up housing 700, whereby the existing tube 1 is cut off. With the cutting method, since the cutting wheel 701 has a smooth outer circumferential part, it is impossible to cut off an existing pipe 1 made of cast iron and steel. FIG.29(a) and FIG.29(b) show views of a conventional method for inserting a valve in a line without stopping passage of water, which is disclosed in United States Patent No. 3,948,282. With the conventional method shown in these drawings, an existing pipe 1 shown in FIG.29(a) is enclosed and sealed up by a seal-up housing 800. Subsequently, an operation sluice valve 801 is attached to the seal-up housing 800. Thereafter, a circular hole 803 is drilled by using a hole saw 802 in compliance with an already known method. After the drilling is completed, as shown in FIG.29(b), a valve body 804 which is fitted into the drilled circular hole 803 is inserted therein. With the conventional valve inserting method, since the hole 803 which has roughly the same diameter as the inner diameter of the existing pipe 1 is provided, the seal-up housing 800 shown in FIG.29(a) is made longer in the axial direction S and is made large-sized. Furthermore, with the conventional inserting method, since hydraulic pressure is given to the valve body 804 shown in FIG.29(b) with respect to a large area equivalent to the circular hole, the diameter of the valve rod 806 is unavoidably made large. Still furthermore, with the conventional inserting method, the circumferential edge 805 of the hole 803 at the existing pipe 1 is made thin, and pressure resulting from the valve body 804 is applied to the circumferential edge 805, wherein the existing pipe 1 is liable to be broken. FIG.30(a) and FIG.30(b) show the outline of a conventional valve insertion method for inserting a valve in a line without stopping passage of water, which was disclosed in United States Patent No. 4,516,598. In the prior art shown in these drawings, the existing pipe 1 in FIG.30(a) is enclosed and sealed up by an seal-up housing 800. At this time, a hole saw 802 and a valve body 804 are accommodated in advance in the seal-up housing 800. Thereafter, a circular hole is drilled at the existing pipe 1 by the hole saw 802. After the drilling is completed, the seal-up housing 800 is turned as shown by the arrow 850 in FIG.30(a). After that, a valve body 804 is inserted into the circular hole 803 in FIG.30(b). FIG.31 shows the outline of a conventional valve insertion method for inserting a valve in a line without stopping passage of water, which was disclosed in United States Patent No. 1,989,768. In the prior art shown in this drawing, the existing pipe 1 in FIG.31 is enclosed and sealed up by a seal-up housing 501. At this time, cutting equipment 500 and a sluice valve 510 are accommodated in advance in the seal-up housing 501. After the cutting equipment 500 having a blade 502 cuts off and removes the existing pipe 1, the sluice valve is inserted instead of the cutting equipment 500. The prior arts shown in FIG.30(a), 30(b), and FIG.31 are able to quickly insert a valve after the cutting is completed. But with the prior arts shown in FIG.30(a), 30(b), and FIG.31, since it is necessary to accommodate a hole saw 802 or cutting equipment 500, the size of which is equivalent to that of the valves 804 and 510 to be inserted, in the seal-up housing 800 or 501, the seal-up housings 800 and 501 are obliged to be large-scaled. The present invention has been developed to solve the problems inherent to the prior arts, and it is therefore a major object of the invention to provide a piping structure in which an existing pipe is scarcely damaged, an existing pipe slitting method by which the existing pipe can be slit to such a shape as the existing pipe is scarcely damaged, and a method for inserting a valve in a line without stopping passage of fluid. In the invention, "existing pipe" means a pipe through which fluid such as water flows and is generally buried under the ground. "Seal-up" does not mean "completely sealed" but means such a state where work can be carried out without stopping passage of water or fluid. Therefore, "seal-up housing" means a housing which has such a pressure resisting capacity, by which it can withstand the pressure of fluid flowing through the existing pipe, and has a sealing capacity to some degree. Furthermore, "enclosed and sealed up in an airtight state" means such a sealed up state where work such as inserting a valve in a line after cut-off or slitting is not hindered, for example, wherein a water discharge port is provided at the seal-up housing and is made open during slitting of an existing pipe, and cutting chips may be discharged through the discharge port together with water. Since a "cutting tool" used in the present slitting method has a plurality of blades, the corresponding cutting tool does not include a cutting chip and a cutter wheel having a single continuous blade. A columnar cutting tool having a plurality of blades on its tip end and its outer circumferential surface is used. Here in the specification, "pillar shape" means a conical trapezoidal shape in addition to a columnar shape, and includes such a shape, in which a conical shape is added to a column, and a conical shape. Furthermore, it may be of a short-pillar shape in comparison with the outer diameter of a cutting tool. Furthermore, in a housing of slitting an existing pipe having mortar lining on its inner circumferential surface, it is preferable that a cutting tool having a plurality of blades made of an ultra-hard alloy, or a cutting tool, the blades of which are made of diamond grains, is used. Furthermore, in the invention, "slitting" means slitting a part of a pipe wall by rotating a plurality of blades. Furthermore, "slitting motion" means causing a plurality of blades to rotate on the cutter shaft. On the other hand, "feeding motion" means causing the abovementioned cutting tool to move to the position where a new part of the pipe wall can be progressively cut off or slit by the cutting tool. In the invention, "feeding the cutting tool roughly in the cross direction of the existing pipe and causing the seal-up housing to turn in the circumferential direction of the existing pipe" means both housings, one of which is turning the seal-up housing after the cutting tool is fed roughly in the cross or diametrical direction of an existing pipe, and the other of which is turning the seal-up housing while feeding the cutting tool roughly in the cross or diametrical direction of an existing pipe. Furthermore, in the invention, "inserting a valve (in a line)" does not mean physically inserting a valve or valve body in a cut-open section of an existing pipe but means installing a valve, which can stop water or regulate the flow quantity in an existing line, in the corresponding line. Herein, "valve" means the entire valve, that is, valve assembly, including a valve body, valve housing, valve rod, etc. Furthermore, "valve body" means a member which clogs a flow passage, in the case of a sluice valve, it is generally called a gate, and in the case of a butterfly valve, it is a member which turns around the valve rod, Still furthermore, "valve housing" means a member which accommodates the valve body, regardless of its opened or closed state of the valve body. In order to achieve the abovementioned object of the invention, a piping structure according to the invention is provided with an existing pipe, a seal-up housing, a sluice valve body and a valve rod. The abovementioned existing pipe has a slit groove obtained by notching the corresponding existing pipe in a range of approximately 180 degrees in the circumferential direction thereof. The abovementioned seal-up housing is divided into plural sections in the circumferential direction of the abovementioned existing pipe and encloses and seals up the existing pipe in an airtight state. The sluice valve body has rubber packing which is brought into contact with the inner circumferential surface of the existing pipe and a cut-off surface forming the abovementioned slit groove in the corresponding existing pipe in the open state (closed state). The sluice valve body moves in the diametrical direction of the abovementioned existing pipe in the seal-up housing and invades the existing pipe through the slit groove, wherein the abovementioned rubber packing stops a stream of fluid in the existing pipe. The abovementioned valve rod causes the valve body to move roughly in the cross direction. In a preferred embodiment of the invention, the slit groove is formed by slitting an existing pipe by the cutting tool. Furthermore, in another preferred embodiment of the invention, the slit surface forming the abovementioned slit groove is formed so that the angle with respect to the surface of the existing pipe at the corresponding part is set in a range from 45 degrees through 90 degrees. Furthermore, in still another preferred embodiment of the invention, both end portions of the abovementioned slit groove in the circumferential direction are made roughly U-shaped. A piping structure according to the invention is completed by inserting a valve in a line, by a method for inserting a valve in a line withoutstopping passage of fluid according to the invention, after slitting an existing pipe by, for example, an existing pipe slitting method of the invention. Furthermore, "without stopping passage of fluid (water)" means that work is carried out without stopping a stream of fluid (for example, water) flowing in a line. That is, in an existing pipe slitting method according to the invention, a cutting tool, which is rotatably supported on the axial line established roughly in the cross direction of an existing pipe and is provided with a plurality of blades on the tip end face and outer circumferential surface of the columnar portion thereof, is accommodated in a seal-up housing in a state where the cutting tool is attached to the abovementioned seal-up housing while enclosing, in an airtight state, a part of the abovementioned existing pipe by the abovementioned seal-up housing which is divided into plural sections in the circumferential direction of the existing pipe. Subsequently, the abovementioned cutting tool is fed roughly in the cross direction of the abovementioned existing pipe in a state of performing a slitting motion to slit the abovementioned existing pipe by rotations of the abovementioned cutting tool by causing the abovementioned cutting tool to rotate on the abovementioned axial line by power of a prime mover, wherein the abovementioned existing pipe is slit by the abovementioned cutting tool in a range of approximately 180 degrees in the circumferential direction thereof by causing the abovementioned cutting tool to perform a feed motion with the abovementioned cutting tool turned in the abovementioned circumferential direction by causing at least a part of the abovementioned seal-up housing to turn in the abovementioned circumferential direction of the abovementioned existing pipe. After the existing pipe is slit in a range of approximately 180 degrees by the abovementioned cutting tool in conjunction with a slitting method according to the invention, a valve is inserted in a line. The valve body of the valve invades the existing pipe through the slit groove, clogs the slit groove itself, and is pressure-fitted to the inner circumference of the existing pipe, thereby closing the abovementioned existing pipe. According to the invention, a cutting tool, the axial line of which is set in the diametrical direction of an existing pipe, is fed in the circumferential direction of the existing pipe to slit the existing pipe like a deep groove. Therefore, since the peripheral edge portion of the slit groove at the existing pipe is not made thin, there is no fear that the existing pipe is damaged when a valve body is fitted in the abovementioned slit groove. Furthermore, in the slitting method, "slitting in a range of approximately 180 degrees in the circumferential direction" means slitting through an existing pipe to such a degree that the valve body having a size approximate to the inner diameter of the existing pipe can be inserted thereinto through the slit groove. FIG.1 is a cross-sectional view of a seal-up housing showing the first preferred embodiment of the invention, FIG.2 is a longitudinally sectional view showing the entirety of a seal-up housing, cutting equipment, etc., FIG.3(a) is a longitudinally sectional view mainly showing cutting equipment before the cutting is started, and FIG.3(b) is a side elevational view of a roughly columnar cutting tool, FIG.4 is a longitudinally sectional view showing the cutting equipment after the cutting is finished, FIG.5(a), FIG.5(b), and FIG.5(c) are, respectively, process views showing the sequence of slitting, FIG.6 is a longitudinally sectional view showing a state where the operation upper chamber is assembled after the cutting is finished, FIG.7 is a sectional view showing a state where the cutting equipment is removed, FIG.8 is a perspective view showing a valve body and a slit groove, FIG.9(a) is a side elevational view of rubber packing, FIG.9(b) is a front elevational view of the rubber packing, FIG.9(c) is a longitudinally sectional view showing a closed state of an existing pipe, and FIG.9(d) is a cross-sectional view showing a closed state of the existing pipe, FIG.10 is a longitudinally sectional view showing a state where the valve body and valve cover of a sluice valve are housed in the operation upper chamber, FIG.11 is a sectional view showing a state of inserting a valve, FIG.12 is a sectional view showing the completed state, FIG.13(a) is a partially sectioned side elevational view showing a seal-up housing according to a modified version of the first preferred embodiment, FIG.13(b) is a bottom view showing the second split housing, FIG.14(a) is a cross-sectional view showing a state where the seal-up housing is attached to an existing pipe, FIG.14(b) is a plan view of the second split housing, FIG.15 is a longitudinally sectional view showing the completed state when the valve is open, FIG.16 is a cross-sectional view showing the completed state when the valve is open, FIG.17 is a longitudinally sectional view showing the completed state when the valve is closed, FIG.18 is a cross-sectional view showing the completed state when the valve is closed, FIG.19 is a cross-sectional view of the seal-up housing, FIG.20 is a longitudinally sectional view showing the entirety of the seal-up housing, cutting equipment, etc. FIG.21(a) is a longitudinally sectional view mainly showing the cutting equipment before the cutting is started, FIG.21(b) is a sectional view of a columnar cutting tool, FIG.22 is a longitudinally sectional view showing the cutting equipment after the cutting is finished, FIG.23(a), FIG.23(b), and FIG.23(c) are, respectively, a process view showing the sequence of slitting, FIG.24 is a longitudinally sectional view showing a state after the cutting is finished, FIG.25(a), FIG.25(a), and FIG.25(a) are, respectively, front elevational views showing modified versions of the cutting tool, FIG.25(d) is a sectional view showing another method for forming a slit groove for the piping structure, FIG.25(e) is a perspective view showing still another method for forming a slit groove for the piping structure, FIG. 26 is a brief sectional view showing a conventional existing pipe cut-off method, FIG.27 is a sectional view showing another conventional method, FIG.28 is a sectional view showing still another conventional method, FIG.29(a) is a sectional view showing a conventional drilling method without stopping passage of water, and FIG.29(b) is a sectional view showing a conventional method for inserting a valve in a line without stopping passage of water. FIG.30(a) is a sectional view showing a state before cutting by a conventional valve insertion method for inserting a valve in a line without stopping passage of water, and FIG.30(b) is a sectional view after a cutting is completed by the conventional valve insertion method for inserting a valve in a line without stopping passage of water, FIG.31 is a sectional view showing a state after a valve is inserted by another conventional valve insertion method for inserting a valve in a line without stopping passage of water, FIG.32 is a longitudinally sectional view showing a state where a seal-up housing is attached, FIG.33 is a cross-sectional view showing a state where a seal-up housing is attached, FIG.34 is a sectional view showing a state where the cutting tool is attached, FIG.35 is a sectional view showing a state after the cutting is commenced, FIG.36 is a sectional view showing a state after the cutting is completed, FIG.37 is a longitudinally sectional view showing a piping structure after a valve is inserted, FIG.38 is a longitudinally sectional view showing a state where the valve is closed, and FIG.39 is a cross-sectional view showing a state where the valve is closed. The invention will be more apparently understood on the basis of the following description of preferred embodiments with reference to the accompanying drawings. In the accompanying drawings, the same reference numbers in a plurality of drawings indicate the same or equivalent parts. FIRST PREFERRED EMBODIMENT FIG.1 through FIG. 12 show a first preferred embodiment. Hereinafter, a description is given, in the order of processes, of an existing pipe slitting method and a method for inserting a valve in a line without stopping passage of water according to the first preferred embodiment. Cutting equipment (Slitting equipment) As shown in FIG.2, in the preferred embodiment, a first central seal-up housing 2A and a pair of left and right second seal-up housings 2B are used. As shown in FIG.1, the abovementioned first seal-up housing 2A is provided with a first and second split housings 221 and 222, which are obtained by being divided into two sections in the circumferential direction, and a guide bushing 222a. Furthermore, the second seal-up housings 2B (FIG.2) are also divided into two sections in the circumferential direction. As shown in FIG.3(a), rubber rings 224 are used to seal up between the respective housings 221 (FIG.2), 222, 2A and 2B and between the second seal-up housings 2B and the existing pipe 1. The abovementioned second split housing 222 has a bifurcated portion 222b protruding in the diametrical direction C of the existing pipe 1, and the main bearing 232 is attached to the abovementioned bifurcated portion 222b so as to freely advance and retreat in the diametrical direction C of the existing pipe 1 via the guide bushing 222a. Rubber rings 224 are used to seal up between the guide bushing 222a, bifurcated portion 222b and the main bearing 232. An opening 222c into which a columnar cutting tool 230 is inserted is formed at the abovementioned bifurcated portion 222b at the second split housing 222. Cutting equipment 3 is attached to the guide bushing 222a fixed at the abovementioned first seal-up housing 2A via the main bearing 232. That is, a first motor 231 (an example of a prime mover) for rotating a cutting tool is fixed upward of the main bearing 232. On the other hand, the cutting tool 230 is disposed inside of the abovementioned main bearing 232 (cutter attaching housing). A cutting tool 230 is formed to be integral with the main shaft (cutter shaft) 233 rotatably supported at the main bearing 232. The first motor 231 causes the cutting tool 230 to rotate via a coupling 234 fixed at the output shaft 231a of the first motor 231 and the main shaft 233. As shown in FIG.3(b), the abovementioned cutting tool 230 has a plurality of blades 230f on the roughly columnar tip end surface 230d and outer circumferential surface 230e. Furthermore, the main shaft 233 is formed on the cutting tool 230 to be integral therewith. As shown in FIG.1, the axial line 233a of the cutting tool 230 and main shaft 233 is established in the diametrical direction C of the existing pipe 1. The cutting tool 230 carries out a cutting motion by rotating around the axial line 233a set in the diametrical direction C of the existing pipe 1. Moreover, the tip end of the cutting tool 230 is pointed to be conical. A cutting feed frame 236 is fixed at the abovementioned bifurcated portion 222b in FIG.3(a). The cutting feed frame 236 is provided with long bolts 236a fixed at the bifurcated portion 222b and a top plate 236b fixed at the upper ends of the long bolts 236a. A male lead screw 237 for cutting feed is screwed in a bushing 236c secured at the abovementioned top plate 236b of the cutting feed frame 236. By turning and screwing the male lead screw 237 for cutting feed in the cutting feed direction C, the main bearing 232 advances in the cutting feed direction C. Therefore, by feeding the cutting tool 230 together with the main bearing 232 in the cutting feed direction C and causing the cutting tool to be advanced into the opening 222c, it is possible to slit the existing pipe 1 by the cutting tool 230 as shown in FIG.4. Furthermore, since the guide bushing 222a is fixed at the cutting feed frame 236 via a connection metal fitting 238 in FIG.1, the guide bushing 222a can be withdrawn together with the cutting feed frame 236 after the slitting is completed. In the preferred embodiment, a housing turning device 4 in FIG.2 is provided, which turns the first seal-up housing 2A around the existing pipe 1. The housing turning device 4 has a pair of second motors 242 for turning the seal-up housing. The corresponding second motor 242 rotates the drive gear 244 for turning the seal-up housing via the output shaft 247. The corresponding drive gear 244 rotates the driven gears 245 for turning the seal-up housing, which are fixed at the first seal-up housing 2A. Therefore, by turning the first seal-up housing 2A by approximately 180 degrees around the existing pipe 1 while rotating the cutting tool 230 in a cutting feed state in FIG.4, it is possible to slit the existing pipe 1 and to form a slit groove 12C in FIG.8. As shown in FIG.3, the second seal-up housing 2B constitutes a slip preventing member 5A. The corresponding second seal-up housing 2B is divided into two sections in the circumferential direction (R) (FIG.1) of the existing pipe 1. A number of set screws 251 are provided in the circumferential direction R (FIG.1) at two points spaced from each other in the axial direction S of pipe 1. A rotation guiding portion 250 which slides via a liner 252 is secured at the connection portion between the abovementioned first seal-up housing 2A and the second seal-up housing 2B. The abovementioned pair of second seal-up housings 2B are fixed at the existing pipe 1 by the abovementioned set screws 251. The abovementioned second seal-up housings 2B guide the first seal-up housing 2A via the abovementioned rotation guiding portion 250 and prevent the first seal-up housing 2A from slipping or shaking in the axial direction S of the existing pipe 1. Therefore, the first seal-up housing 2A is able to be smoothly turned when turning around the existing pipe 1. Furthermore, a ball bearing may be used instead of a liner 252. Slitting process Next, a description is given of a sequence of slitting. First, in a state where fluid (water) is flowing in the existing pipe 1 in FIG.2, the workmen attach the first and second seal-up housings 2A and 2B to the existing pipe 1 and both split housings 221 and 222 by assembling bolts 228 in FIG.1. Thus, as shown in FIG.2, the first and second seal-up housings 2A and 2B enclose and seal up the existing pipe 1 in an airtight state. Furthermore, the cutting equipment 3 is attached, in advance, to the guide bushing 222a of the first seal-up housing 2A. Next, as shown in FIG.5(a) and FIG.5(b), a position to be slit by a cutting tool 230 is determined. That is, the housing turning device 4 in FIG.2 is driven, wherein the first seal-up housing 2A and cutting equipment 3 are turned until the position wherein the axial line 233a (FIG.5) of the cutting tool 230 is made roughly horizontal. Next, as the workmen drive the first motor 231 in FIG.1, the corresponding first motor 231 rotates the cutting tool 230 around the axial line 233a of the main shaft 233, wherein the cutting tool 230 is caused to perform a slitting motion by which the existing pipe 1 is slit by rotations of the cutting tool 230. In a state where the cutting tool 230 is performing a slitting motion, the workmen screw the male lead screw 237 for cutting feed in the cutting feed direction C, concurrently, as shown by an alternate long and two dashes line in FIG.5(b), the cutting tool 230 advances to the position where the tip end surface 230d thereof passes through a part of the wall 1a of the existing pipe 1. Thus, the cutting feed of the cutting tool 230 in the direction C is completed. After that, as the workmen drive the second motor 242 for turning the housing in FIG.2, the first seal-up housing 2A is turned, via a pair of drive gears 244 and driven gears 245, around the existing pipe 1 in a state where it is guided by the second seal-up housings 2B. Thereby, as shown in FIG.5(c), the cutting tool 230 rotates on the main shaft 233 while turning along the outer circumference of the existing pipe 1 by approximately 180 degrees (for example, 160 degrees) together with the first seal-up housing 2A, wherein the existing pipe is semi-annularly slit to form a slit groove 12C thereat. The corresponding slit groove 12C is cut open in a range of approximately 180 degrees in the circumferential direction R of the existing pipe 1. That is, the abovementioned second motor 242 (FIG.1) turns the cutting tool 230 in the circumferential direction R by causing the first seal-up housing 2A to be turned in the circumferential direction R (FIG.1) of the existing pipe 1, as shown in FIG.5(b) and FIG.5(c), a cutting feed motion is given to the cutting tool 230. Thereby, the cutting tool 230 semi-annularly slits the abovementioned existing pipe 1 in order to form a slit groove 12C at the existing pipe 1. After the corresponding slitting is completed, the cutting tool 230 is returned to its original position as shown by the arrow of an alternate long and two dashes line. Thereafter, the workmen remove the housing turning device 4 in FIG.2. Furthermore, by attaching a water discharge valve at the main bearing 232, cutting chips may be discharged through the water discharge valve when slitting. Cutting equipment removing equipment Next, the workmen remove the cutting equipment 3 by the method described below. That is, as shown in FIG.6, the workmen connects an operation sluice valve 273 to the bifurcated portion 222b, and furthermore an operation upper chamber 274 is connected to the operation sluice valve 273 so as to overlap thereon. When carrying out the connection, the workmen connect a frame 236 for cutting feed to the tip end of a lifting shaft 276 passing through the operation upper chamber 274. After the connection is finished, the workmen remove nuts 239. After the nuts 239 are removed, the workmen raise the lifting shaft 276 in FIG.7 and remove the cutting equipment 3 from the first seal-up housing 2A into the operation upper chamber 274. After the cutting equipment is removed, the workmen close the operation sluice valve 273. After the valve is closed, the workmen separate the operation upper chamber 274 from the operation sluice valve 273. Next, a description is given of a structure of sluice valve body of a valve to be inserted in a line. A valve is provided with a sluice valve body 8a shown in FIG.8. The corresponding sluice valve body 8a is provided with rubber packing 8d. The corresponding rubber packing 8d closes the slit groove 12C as the sluice valve body 8a invades inside of the existing packing 1 through the slit groove 12C, and is pressure-fitted to the inner surface 1b of the existing pipe 1. That is, the rubber packing 8d consists of a first rubber packing portion 8d1 pressure-fitted to the slit surface 12f of the slit groove 12C and a second rubber packing portion 8d2 pressure-fitted to the inner circumferential surface 1b of the existing pipe 1 in a series as shown in FIG.9(c) and FIG.9(d). Furthermore, a first attaching groove 8a1 and a second attaching groove 8a2 are formed at the abovementioned sluice valve body 8a in order to attach the first and second rubber packing portions 8d1 and 8d2 which are shown in FIG.9(a) and FIG.9(b). Valve inserting process Next, the workmen accommodate the valve cover 8b in FIG.10 and the abovementioned sluice valve body 8a in the operation upper chamber 274 and connect the corresponding operation upper chamber 274 to the operation sluice valve 273. The sluice valve 8A is provided with a spindle 8c for opening and closing the sluice valve body 8a. The corresponding sluice valve 8A constitutes a valve so that the sluice valve body 8a in FIG.8 invades the existing pipe 1 through the slit groove 12C and the rubber packing 8d secured at the sluice valve body 8a is pressure-fitted to the cutting surface 12f of the existing pipe 1 and the inner circumferential surface 1b of the existing pipe 1. That is, the existing pipe 1 constitutes a part of the valve housing of the sluice valve 8A. After the operation upper chamber 274 in FIG.10 is attached in place, the workmen opens the operation sluice valve 273 as shown in FIG.11 and shifts down the lifting shaft 276, wherein the valve cover 8b is brought into contact with the bifurcated portion 222b. After the valve cover 8b is brought into contact therewith, the workmen connect the valve cover 8b to the bifurcated portion 222b by flange bolts 8e. After the connection, the workmen withdraw the operation upper chamber 274 and operation sluice valve 273. Thereafter, the workmen press rubber rings 264 into the packing insertion portions 260 of the second seal-up housing 2B in FIG.12 and attach split press rings 265 to the second seal-up housing 2B. Thus, the sluice valve 8A is disposed at the point corresponding to the slit groove 12C, wherein the sluice valve 8A is inserted in a line 1A. Herein, in the first preferred embodiment, since rubber packing 8d is pressure-fitted to the slitting surface 12f and the inner circumferential surface 1b of the existing pipe 1 in FIG.8, that is, the existing pipe 1 is used as a valve housing, a great external force is applied to the existing pipe 1. However, in this preferred embodiment, the width of a slit groove 12C formed at the existing pipe 1 is made small, in particular no thin portion is produced at the existing pipe 1, and there is no fear that the existing pipe 1 is damaged when the line 1A is closed with a sluice valve body 8a. Furthermore, since, when the sluice valve body 8a is closed, the sluice valve body 8a is supported in the axial direction S of pipe 1 on the slitting surface 12f via the first rubber packing portion 8a1, the valve body 8a is scarcely deformed even though it is given pressure when stopping water. Therefore, it is possible to make the spindle 8c slender. Furthermore, since the width of the slitting groove 12C is small, the force, with which the valve body 8a is pressed upward by hydraulic pressure, is also small. Therefore, the spindle 8c can be made slender. Furthermore, in the first embodiment, although a seal-up housing is divided into the first seal-up housing 2A and second seal-up housing 2B and a part of the seal-up housing, that is, the first seal-up housing 2A is turned, in the present invention, the first seal-up housing 2A and second seal-up housing 2B may be formed to be integral with each other. In this housing, a slip preventing member is separately provided aside of the seal-up housing, wherein the entire seal-up housing is turned. This example is shown by the following modified version of the embodiments. Modified version FIG.13 through FIG.24 show a modified version of the first preferred embodiment. Hereinafter, after a description is given of the seal-up housing of the present modified version, a description is given of a piping structure thereof. Seal-up housing As shown in FIG.13(a), the seal-up housing 2 is divided into the first and second split housings 211 and 212, wherein the split surface 215 is sealed up by rubber packing 214 shown in FIG.13(b). Furthermore, the split surface 215 of the two split housings 211 and 212 is constructed so that they are brought into contact with each other in a metal-to-metal touching state. Furthermore, a packing insertion portion 260 into which rubber packing 264 in FIG.15 is inserted is provided at both ends of the seal-up housing 2. As shown in FIG.14(b), a bolt insertion opening 217 for fixing a valve cover and a bolt insertion opening 218 for fixing an operation sluice valve are formed at a flange 216 of the second split housing 212 in FIG.14(a). A hole 219 is to insert an assembling bolt thereinto. Piping structure FIG.15 through FIG.18 show a piping structure. In FIG.15, a slit groove 12C is formed at the existing pipe 1. As shown in FIG.16, the corresponding slit groove 12C is notched and cut open in a range of approximately 180 degrees in the circumferential direction of the existing pipe 1. The corresponding slit groove 12C is formed by slitting the existing pipe 1 by a cutting tool described 'later. As shown in FIG.15, the corresponding groove 12C is formed so that both ends 12c1 thereof in the circumferential direction is made roughly U-shaped. Thus, since both ends 12c1 of the slit groove 12C draws a smooth curve, the sealing at the corresponding both ends 12c1 is facilitated. Furthermore, the portion excluding the abovementioned both ends 12c1 at the abovementioned slit groove 12C is formed to a fixed groove width W. Furthermore, the slit surface 12f forming the abovementioned slit groove 12C is set in a range from 45 through 90 degrees with respect to the surface 1c of the existing pipe 1 at the corresponding portion. That is, as shown in FIG.16, the existing pipe 1 does not have any thin portion at the peripheral edge portion 12Ce of the slit groove 12C. Therefore, as shown in FIG.17 and FIG.18, even though rubber packing 8d of the valve body 8a is pressure-fitted to the slit surface 12f, there is no fear that the existing pipe 1 is damaged. For this reason, it is possible to repeatedly open and close the sluice valve 8A. The abovementioned seal-up housing 2 is divided into two sections in the circumferential direction R of the existing pipe 1 and is sealed up by rubber packing 214, wherein the existing pipe 1 is enclosed and sealed up in an airtight state. The first split housing 211 is formed along the outer circumferential surface of the existing pipe 1. On the other hand, the second split housing 212 has a hole 212d which permits the sluice valve body 8a to move in the diametrical direction C of the existing pipe 1. The valve cover 8b is fixed at the abovementioned second split housing 212. The corresponding valve cover 8b clogs the hole 212d for moving the abovementioned second split housing 212. The abovementioned valve body 8b and the second split housing 212 form a space in which the sluice valve body 8a is accommodated when the valve is opened in FIG.16. As shown in FIG.17, the abovementioned sluice valve body 8a has rubber packing 8d. The corresponding rubber packing 8d is formed so that the first rubber packing 8d1 which is brought into contact with the slit surface 12f (shown with a broken line in FIG.18) forming the slit groove 12C and the second rubber packing 8d2 which is brought into contact with the inner circumferential surface 1b of the existing pipe 1 are made integral with each other. The corresponding rubber packing 8d is baked to the sluice valve body 8a to be integral therewith. As shown in FIG.15 and FIG.17, the abovementioned sluice valve body 8a is moved in the diametrical direction C of the existing pipe 1 in the seal-up housing 2 if the spindle (valve rod) 8c is turned. The abovementioned sluice valve body 8a invades the inside of the existing pipe 1 through the abovementioned slit groove 12C, wherein the rubber packing 8d is brought into contact with the slit surface 12f and the inner circumferential surface 1b of the existing pipe 1, and fluid flowing in the existing pipe 1 is stopped. Furthermore, the inner circumferential surface 1b of the existing pipe 1 in the present preferred embodiment is finished with mortar lining. Cutting equipment (Slitting equipment) In the slitting process, as shown in FIG.19, the abovementioned seal-up housing 2 is provided with the first and second split housings 211 and 212 split into two sections in the circumferential direction and a guide bushing 212a. The abovementioned second split housing 212 has a bifurcated portion 212b protruding in the diametrical direction C of the existing pipe 1, wherein a main bearing 232 to support the main shaft 233 is attached to the corresponding bifurcated portion 212b slidably in the diametrical direction C of the existing pipe 1 via the abovementioned guide bushing 212a. As shown in FIG.21(a), rubber rings 224 are used to seal up between the abovementioned guide bushing 212a, bifurcated portion 212b and main bearing 232. An opening 212c in which a columnar cutting tool 230 is inserted is formed at the abovementioned bifurcated portion 212b in the second split housing 212. Cutting equipment 3 is attached to the guide bushing 212a fixed at the abovementioned seal-up housing 2 via the main bearing (tool attaching housing) 232. That is, A motor (one example of a prime mover) 231 for rotating the tool is fixed upward of the main bearing 232. On the other hand, the abovementioned cutting tool 230 is disposed inside the abovementioned main bearing 232. The cutting tool 230 is formed to be integral with and at the main shaft (cutter shaft) 233 which is rotatably supported at the main bearing 232. The abovementioned motor 231 causes the cutting tool 230 to rotate via the output shaft 231a of the corresponding motor 231 and a coupling 234 fixed at the main shaft 233. As shown in FIG.21(b), the abovementioned cutting tool 230 has a plurality of blades 230f on the roughly columnar tip end surface 230d and outer circumferential surface 230e. Furthermore, the abovementioned main shaft 233 is formed integral with the cutting tool 230. Furthermore, in the preferred embodiment, in order that the slitting surface 12f is tapered as shown in FIG.15, a tapered portion 230t is provided at the cutting tool 230 in FIG.21(b). Furthermore, in order to prevent the abovementioned tapered portion 230t from entering toward the center of the existing pipe 1 excessively, the cutting tool 230 is provided with a cutting feed stopper 230s fixed thereon. The cutting feed stopper 230s is made of hard resin, and it is favorable that the cutting feed stopper 230s is provided with grooves through which cutting chips are permitted to escape. In the preferred embodiment, the cutting feed stopper may be secured at the guide bushing 212a instead of being secured at the cutting tool 230. As shown in FIG.19, the axial line 233a of the abovementioned cutting tool 230 and main shaft 233 is set in the diametrical direction C of the existing pipe 1. The abovementioned cutting tool 230 carries out a slitting motion by being rotated around the abovementioned axial line 233a established in the diametrical direction C of the abovementioned existing pipe 1. A cutting feed frame 236 is fixed at the abovementioned bifurcated portion 212b in FIG.21(a). The corresponding cutting feed frame 236 is provided with long bolts 236a fixed at the abovementioned bifurcated portion 212b and a top plate 236b fixed on the upper ends of the corresponding long bolts 236a. A male lead screw 237 for cutting feed is screwed in a bushing 236c secured at the abovementioned top plate 236b of the abovementioned cutting feed frame 236. By turning and screwing the male lead screw 237 for cutting feed in the cutting feed direction C, the main bearing 232 advances in the cutting feed direction C. Therefore, by causing the cutting tool 230 to advance in the opening 212c by feeding the cutting tool 230 together with the main bearing 232 while rotating the cutting tool 230, it is possible to slit the existing pipe 1 by the cutting tool 230 as shown in FIG.22. Furthermore, the abovementioned guide bushing 212a is fixed at the cutting feed frame 236 via a connection metal fitting 238 in FIG.19, and it is withdrawn together with the cutting feed frame 236 after the slitting is completed. As shown in FIG.20, a slip preventing member 5 is provided at both sides of the abovementioned seal-up housing 2. The corresponding slip preventing member 5 is fixed at the existing pipe 1 by a number of set screws 251 and is brought into contact with both sides of the seal-up housing 2 via a liner 252. Thereby, the slip preventing member 5 guides the seal-up housing 2 and prevents the seal-up housing 2 from slipping or shaking in the axial direction S of the existing pipe 1. Therefore, the seal-up housing 2 is smoothly turned when turning around the existing pipe 1. Furthermore, a pressing screw 253 presses the liner 252 to the seal-up housing 2. Slitting process Next, a description is given of a sequence of slitting. First, in a state where fluid (water) is flowing in the existing pipe 1 in FIG.20, the workmen attach the seal-up housing 2 to the existing pipe 1 and assemble both split housings 211 and 212 by assembling bolts (not illustrated). Thus, as shown in FIG.20, the seal-up housing 2 encloses and seals up the existing pipe 1 in an airtight state. Furthermore, the cutting equipment 3 is attached, in advance, to the guide bushing 212a. Next, as shown in FIG.23(a) and FIG.23(b), a slitting position to be slit by the cutting tool 230 is determined. That is, the workmen, manually or by using a winch, turn the seal-up housing 2 and cutting equipment 3 to the position where the axial line 233a of the cutting tool 230 is roughly horizontal. Furthermore, in the present embodiment, an operation handle and a speed reduction mechanism, which are used to turn the seal-up housing 2, may be provided. Next, as the workmen drive the motor 231 in FIG.19, the corresponding motor 231 turns the cutting tool 230 around the axial line 233a of the main shaft 233 and causes the cutting tool 230 to perform a slitting motion, by which the existing pipe 1 is slit by the corresponding cutting tool 230. In a state where the cutting tool 230 is performing the corresponding slitting motion, the workmen screw the male lead screw 237 for cutting feed in the cutting feed direction C, concurrently, as shown with an alternate long and two dashes line in FIG.23(b), the tip end surface 230d of the cutting tool 230 advances to the position where the tip end surface passes through a part of the wall 1a of the existing pipe 1. At this time, the cutting feed stopper 230s in FIG.22 is brought into contact with the outer circumferential surface of the existing pipe 1. Thus, the cutting feed by the cutting tool 230 is completed. After the cutting feed is completed, the workmen turn the seal-up housing 2 around the existing pipe 1 as shown in FIG.23 (b) and FIG.23 (c), thereby, the cutting tool 230 is turned around the axial line 233a while turning by approximately 180 degrees (for example, 160 degrees) along the outer circumference of the existing pipe 1 together with the seal-up housing 2, wherein the existing pipe 1 is semi-annularly slit, and a slit groove 12C is formed at the existing pipe 1. After the slitting is completed, the cutting tool 230 in FIG.23(c) is returned to the original position as shown with the arrow of an alternate long and two dashes line. Furthermore, in order that the water stopping made by the sluice valve 8A (FIG.16) inserted in a line later is made sufficient, it is necessary that the cutting tool 230 is returned to the central position of the cutting groove 12C. Cutting equipment removing process Next, the workmen remove the cutting equipment 3 in FIG.24 by a method similar to that in the abovementioned embodiment, and further, as shown in FIG.15 and FIG.16, the sluice valve 8A is inserted into a place corresponding to the slit groove 12C in a line 1A. Thus, in the present piping structure, since the width of the slit groove 12C in FIG.15 is small, it is possible to decrease the size of the seal-up housing 2. A cutting tool for slitting the slit groove 12C according to the invention may be a conical trapezoidal type as shown in FIG.25(a), a conical type as shown in FIG.25(b), or a columnar type as shown in FIG.25(c). Furthermore, as blades 230f, a number of diamond grains may be employed, as shown in FIG.25(b) and FIG.25(c), in addition to ultra hard chips. Furthermore, in the present piping structure, as a method for slitting the existing pipe 1, it is not necessary to turn the seal-up housing 2, but as shown in FIG.25(d), a roughly columnar cutting tool 230 is parallelly moved in the circumferential direction R in order to form a slit groove 12C. Furthermore, as another method, as shown in FIG.25(e), the slit groove 12C may be also formed by machining the existing pipe 1 so as to press the side of a cutting tool 230 consisting of a column-shaped miller to the existing pipe 1. SECOND PREFERRED EMBODIMENT FIG.32 through FIG.39 show a second preferred embodiment. The second preferred embodiment is preferably employed for a pipe of small diameter, for example, 3 inches through 12 inches. The seal-up housing and the piping structure after an appointed valve is inserted are approximate to the modified versions illustrated in FIG.13 through FIG.24. Herein, parts which are different from the modified versions are mainly described below. Seal-up housing In this preferred embodiment, as shown in FIG. 32 and FIG. 33, a sluice valve body 8a and a spindle 8c are accommodated in advance in the seal-up housing 2. A valve cover 8b also constitutes the seal-up housing 2 together with the first split housing 211 and the second split housing 212. As shown in FIG.33, a bifurcated portion 212b, through which a cutting tool 230 (FIG.34) passes, protrudes and is provided in the second split housing 212. The main bearing 232 is fixed at the abovementioned bifurcated portion 212b in FIG.34. The main bearing 232 supports the main shaft 233 of the cutting tool 230 when performing a cutting operation. On the other hand, a discharge opening 248 which discharges cutting chips produced during a cutting operation together with water is provided at the abovementioned bifurcated portion 212b. Furthermore, a discharge valve may be connected to the discharge opening 248 as necessary. Cutting equipment A ball valve (operation valve) 277 is connected to the abovementioned main bearing 232 and cutting equipment 3 is attached to the corresponding ball valve 277. The cutting equipment 3 is used to form a semi-annular slit groove 12C (FIG.32) as in the abovementioned first preferred embodiment, wherein the cutting tool 230 is rotated by a rotating force of a prime mover such as a motor and an engine along with feeding the cutting tool 230 in the diametrical direction C, and a cutting motion is performed. The structure of the cutting equipment 3 is similar to that of a hole saw type drilling machine used without stopping passage of water, which has been already known. Therefore, detailed illustration and description thereof are omitted herein. As shown with an imaginary line in FIG.32, a sluice valve body 8a is disposed in advance at a place corresponding to the slit groove 12C slit by the abovementioned cutting tool 230. Slitting process Next, a description is given of the sequence of slitting. First, the workmen attach a seal-up housing 2 to an existing pipe 1 in a state where water flows in the existing pipe 1 in FIG.33, and concurrently, assemble both split housings 211 and 212 by assembling bolts (not illustrated). After that, the cutting equipment 3 in FIG.34 is attached in advance to the second split housing 212 of the seal-up housing 2 via a ball valve 277. Thus, as shown in FIG.32, the seal-up housing 2 encloses and seals up the existing pipe 1 in an airtight state. Next, the seal-up housing 2 is turned, and as shown in FIG.35, a slitting position carried out by the cutting tool 230 is established. That is, manually or by using a winch, the workmen turn the seal-up housing 2 and cutting equipment 3 to the position where the axial line 233a of the cutting tool 230 is made roughly horizontal. Furthermore, as the workmen drive the prime mover of the cutting equipment 3, the corresponding prime mover causes the cutting tool 230 to rotate around the axial line 233a of the main shaft 233 and causes a slitting motion to be carried out, by which the existing pipe 1 is slit by rotations of the corresponding cutting tool 230. If the cutting tool 230 is fed in the cutting feed direction C in a state where the cutting tool 230 is performing the corresponding slitting motion, as shown with alternate short and long two-dashed lines, the cutting tool 230 shortly advances to the position where the tip end surface 230d thereof, and penetrates a part of the pipe wall 1a of the existing pipe 1. Thus, the cutting feed of the cutting tool 230in the direction C is completed. After that feed is completed, the workmen turns the seal-up housing 2 around the existing pipe 1 in the circumferential direction R of the existing pipe 1 in FIG.35. Thereby, the cutting tool 230 is turned around the axial line 233a while turning approximately 150 to 160 degrees along the outer circumference of the existing pipe 1 together with the seal up housing 2, wherein the cutting tool 230 semi-annularly slits the existing pipe 1 as in FIG.36, wherein a slit groove 12C is formed in the existing pipe 1. Cutting equipment removing process After the abovementioned slit groove 12C is formed, the discharge opening 248 is clogged by a plug (not illustrated) . After that, the cutting tool 230 is retreated, and the ball valve 277 is closed. After the ball valve is closed, the cutting equipment 3 is removed from the seal-up housing 2. After it is removed, the seal-up housing 2 is turned back from the position shown in FIG.36 to its original position as shown in FIG.37. Thereafter, a rubber ring 264 and a split press ring 265, which are shown in FIG.38, are attached. Here, insertion (installation) of the valve in a line is completed. The sluice valve body 8a is closed as shown in FIG.38 and FIG.39 where optional. Thus, in this preferred embodiment, no operation upper chamber is required, and the operation valve 277 can be made remarkably small. Furthermore, since it is not necessary that, after the slitting is completed, the operation valve 277 is opened and the sluice valve body 8a is accommodated in the seal-up housing 2, the time required for the operation can be remarkably shortened. For example, an engine may be employed in addition to a motor as a prime mover which gives a slitting motion to a cutting tool. Furthermore, a prime mover is installed on the ground, and power of the corresponding prime mover is transmitted to a cutting tool via its cutter shaft by a flexible shaft. Furthermore, after an existing pipe is enclosed and sealed up by a seal-up housing, a cutting tool may be attached to the corresponding seal-up housing. Still furthermore, after the existing pipe 1 is cut off or slit, a branch pipe may be connected to the seal-up housing via a sluice valve. Furthermore, when slitting the existing pipe 1 by a cutting tool, although it is generally favorable that the cutting tool is fed toward roughly the center in the diametrical direction of the existing pipe as in the respective preferred embodiments, in the present invention, it is not necessary that the cutting tool is moved toward the center thereof. It is satisfactory that the cutting tool is fed in the diametrical direction. Furthermore, the seal-up housing may be divided into three or four sections in the circumferential direction. Still furthermore, a valve body may be inserted from any direction such as upward, sideway or downward. In addition, the present invention is applicable to not only a water pipe but also a gas pipe. That is, fluid flowing in an existing pipe may be gas or oil in addition to water. These are included in the invention.

Claims: A method for inserting a valve in a line without stopping passage of fluid, comprising the steps of: accommodating a cutting tool (230), which is rotatably supported on the axial line (233a) established roughly in the cross direction (C) of an existing pipe (1) and is provided with a plurality of blades (230f) on the tip end face (230d) and outer circumferential surface (230e) of the columnar portion thereof, in a seal-up housing (2,2A,2B) in a state where the cutting tool (230) is attached to said seal-up housing (2,2A,2B) while enclosing, in an airtight state, a part of said existing pipe (1) by said seal-up housing (2,2A,2B) which is divided into plural sections in the circumferential direction of the existing pipe (1); feeding said cutting tool (230) roughly in the cross direction (C) of said existing pipe (1) in a state of performing a slitting motion to slit said existing pipe (1) by rotations of said cutting tool (230) by causing said cutting tool (230) to rotate on said axial line (233a) by power of a prime mover (231), wherein a slit groove cut open in a range of approximately 180 degrees in the circumferential direction (R) of said existing pipe (1) is formed by slitting said existing pipe (1) by said cutting tool (230) in a range of approximately 180 degrees in the circumferential direction (R) thereof by causing said cutting tool (230) to perform a feed motion with said cutting tool (230) turned in said circumferential direction (R) by causing at least a part of said seal-up housing (2,2A,2B) to turn in said circumferential direction (R) of said existing pipe (1); and disposing a sluice valve (8A) having a sluice valve body (8a) for stopping said existing pipe (1), which invades from said slit groove (12C) into said existing pipe (1), clogs said slit groove (12C) and is pressure-fitted to the inner circumferential surface (1b) of said existing pipe (1), at a point corresponding to said slit groove (12C). A method for inserting a valve in a line without stopping passage of fluid as set forth in Claim 1, wherein after said existing pipe (1) is slit through in a range of approximately 180 degrees by said cutting tool (230), said sluice valve (8A) is disposed at said point corresponding to said slit groove (12C). A method for inserting a valve in a line without stopping passage of fluid, as set forth in Claim 1, comprising the steps of: accommodating said sluice valve body (8a) in advance in said seal-up housing (2) in addition to said cutting tool (230) before slitting said existing pipe (1) in said range of approximately 180 degrees by said cutting tool (230); and providing an operation valve (277) on said seal-up housing (2), which enables removal of said cutting tool (230) ; wherein said cutting tool (230) is removed from said seal-up housing (2) after slitting said existing pipe (1) in the range of approximately 180 degrees by said cutting tool (230). A method as set forth in any of Claims 1 to 3, wherein after said cutting tool (230) is fed toward roughly the center of said existing pipe (1) roughly in the cross direction (C) till a position where said cutting tool (230) passes through a part of the wall (1a) of said existing pipe (1), said feeding motion is carried out while causing said cutting tool (230) to perform said slitting motion in a state where said cutting tool (230) passes through said pipe wall (1a). A method as set forth in any of Claims 1 to 4, wherein a tool attaching housing (232) which rotatably supports said cutting tool (230) is provided; a bifurcated portion (222b) projecting roughly in the cross direction (C) of said existing pipe (1) is formed on one of a plurality of divided housings (211,212) obtained by dividing said seal-up housing (2,2A,2B) in said circumferential direction (R) ; said tool attaching housing (232) is attached so as to be able to advance and retreat roughly in the cross direction (C) of said existing pipe (1) with respect to said bifurcated portion (222b); and said seal-up housing (2,2A,2B) is thereby formed. A method as set forth in any of claims 1 to 5, wherein the passaging fluid is water. A piping structure comprising: an existing pipe (1) having a slit groove (12C) notched and cut open so as to cover a range of approximately 180 degrees in the circumferential direction of an existing pipe (1) ; a seal-up housing (2,2A,2B) which is divided into plural sections in the circumferential direction of said existing pipe (1) and seals up said existing pipe (1) in an airtight state; a sluice valve body (8a) which has rubber packing (8d) being in contact with both the inner circumferential surface (1b) of said existing pipe (1) and a slit surface (12f) forming said slit groove (12C) at said existing pipe (1) in a closed state, moves roughly in the cross direction (C) of said existing pipe (1) in said seal-up housing (2,2A,2B), invades from said slit groove (12C) into said existing pipe (1), and stops the passage of fluid in said existing pipe (1) by said rubber packing (8d) being pressure-fitted to said inner circumferential surface (1b) and slit surface (12f); and a valve rod (8b) by which said valve body (8a) is caused to move roughly in the cross direction (C). A piping structure as set forth in Claim 7, wherein said seal-up housing (2,2A,2B) comprises: a first divided housing (211) formed along the outer circumference of said existing pipe (1); a second divided housing (212) having a hole in which said sluice valve body (8a) moves, and accommodating at least a part of said sluice valve body (8a) in an open state; and a valve cover for clogging said hole of said second divided housing (212). Apparatus for inserting a valve in a line without stopping passage of fluid, comprising a cutting tool (230) which is provided with a plurality of blades (230f) on the tip end face (230d) and outer circumferential surface (230e) of the columnar portion thereof, the cutting tool (230) being accomodated in a seal up housing (2, 2A, 2B), the housing (2, 2A, 2B) being divided into plural sections in a circumferential direction (R) of an existing pipe (1) and having means for enclosing a part of said existing pipe (1) in an airtight state; and furhter comprising means for feeding said cutting tool (230) roughly in the cross direction (C) of said existing pipe (1); and a prime mover (231) and means for causing said cutting tool (230) to rotate on an axial line (233a) established roughly in the cross direction (C) of said existing pipe (1) in order to cause said cutting tool (230) to perform a slitting motion to slit said existing pipe (1) by rotations of said cutting tool (230); and means for causing at least a part of said seal up housing (2, 2a, 2b) to turn in the circumferential direction (R) of said existing pipe (1) in order to cause said cutting tool (230) to perform a feed motion with said cutting tool (230) turned in said circumferential direction (R) in order to cut open a slit groove (12c) in a range of approximately 180° in the circumferential direction (R) of said existing pipe (1); the appartus further comprising a sluice valve (8A) having a sluice valve body (8a) for stopping said passage of fluid and means for invading said sluice valve body (8a) from said slit groove (12C) into said pipe (1) in order to clog said slit groove (12C) and to pressure-fit it to the inner circumferential surface (1b) of said existing pipe (1) at a point corresponding to said slit groove (12C).

Inventors: HOMMA HIDESHIGE, SATO TOSHIYUKI, YAMASHITA TAMOTSU, YOKOYAMA GUMPEI, HOMMA, HIDESHIGE, SATO, TOSHIYUKI, YAMASHITA, TAMOTSU, YOKOYAMA, GUMPEI
Applicants: SUIKEN CO LTD, SUIKEN CO., LTD.
Application year: 1998
Main classification: F16L55
IPC codes: F16L55