GB2039656A

GB2039656A - Branch connections to pipes

Info

Publication number: GB2039656A
Application number: GB8001447A
Authority: GB
Original assignee: SEV TRENT WATER AUTHORITY
Current assignee: SEV TRENT WATER AUTHORITY
Priority date: 1979-01-16
Filing date: 1980-01-16
Publication date: 1980-08-13

Abstract

A machine for drilling and tapping and then fixing a ferrule in a main pipe 1 while the pipe is carrying fluid such as water under pressure and to which pipe the machine is clamped has a valve body 5 open at the bottom to the pipe 1. A ball-shaped valve member 11 within the body 5 has a passage 12 through which a drilling and tapping bit 34 is passed to make a tapped hole in the pipe 1. The bit 34 is carried by a spindle 25 rotatable in a spindle carrier 6 detachably mounted on the valve body 5. After the tapped hole has been made the bit 34 is withdrawn above the valve member 11 which is then closed. The spindle carrier 6 is separated from the valve body, the bit 34 replaced by an adaptor carrying a ferrule and the spindle carrier 6 re-engaged with the body 5. The valve member 11 is then opened and the ferrule is passed by the machine through the passage 12 and screwed into the tapped hole. A drain outlet 21 open to the passage 12 allows water to escape to waste when the valve is open carrying with it swarf that would otherwise drop into the main as it is being drilled and tapped. The drain outlet 21 also serves to reduce fluid pressure with the machine so that the design specification for strength can be reduced. In a modification a flexible gasket is inserted between the valve body 5 and the pipe. The gasket can conform to a range of pipe sizes. <IMAGE>

Description

SPECIFICATION Branch connections to pipes This invention relates to the making of branch connections to pipes while the pipes are carrying fluids under pressure, especially main water pipes in orderto take offwatersupplies but is also applicable to main pipes carrying other fluids under pressure, gas mains and oil pipe lines for example.

An essential requirement of a connection to a main service pipe is that it should incorporate a stop valve so as to allow the supply to be cut-off for repairs or if it becomes redundant. Conventionally, connections are made to main water pipes of metal by using a ferrule comprising a tubular body which is threaded externally at one end for engagement in a tapped hole in the water pipe and which is threaded internally at its other end to receive a plug that controls opening and closing of a side opening outlet which is adapted for connection to a water supply pipe. Swivel ferrules are also used in which the fixed outlet of the ferrule is replaced by an outlet that is rotatably mounted on the tubular body by a banjo joint, whereby the water supply pipe can be taken off in any direction.

These ferrules are connected to water pipes, containing water under pressure, using specially designed tapping machines. One type of machine comprises a tubular housing having an open lower end for engagement with the main water pipe, a gate valve within the housing to close the lower end, and an upper end that rotatably supports a removable spindle which can carry either a drilling and tapping tool or a ferrule. In use, the machine is clamped to the water pipe, the tool is connected to the spindle, the gate valve is opened and a hole is drilled and tapped in the water pipe. The tool is then withdrawn from the tapped hole and the gate valve closed so that the spindle can be removed, the tool replaced by the ferrule, and the spindle reinserted. The gate valve is then opened and the ferrule screwed into the taped hole in the water pipe.In another type of machine, the gate valve is omitted and two spindles are provided instead of one, one spindle carrying the tool and the other the ferrule, and the two spindles being interchangeable within the housing so that the one can be used to drill and tap a hole and the other can be used subsequently to inserttheferrule.

A disadvantage with all of these known ferrules is that the provision of a plug valve therein reduces the water flow rate by virtue of the resistance caused by the internal screw thread and the sharp 90 turn into the water outlet. A further disadvantage of the penny ferrule is that the water outlet cannot be taken off in any selected direction, and although this disadvantage has been overcome with the swivel ferrule, this is only achieved by increased complexity and cost.

Our co-pending Patent Application No. also claiming priority from Patent Application No. 7901592, relates to a branch connection to a main pipe which is an improvement on those making use of the known ferrules, particularly in relation to the disadvantages described aobve.

The present invention relates to a machine and method of making connections to pressured main pipes.

The present invention consists in a machine for making a connection to a main pipe while the pipe is carrying a fluid under pressure comprising a tubular housing having an open lower end to be closed by the main pipe, a valve which is rotatably mounted within the housing having a valve member with a sealing surface which lies on a sphere to close a flow-path through the housing from the said lower end, and an upper end that rotatably supports a removable spindle which can carry either a drilling and tapping tool or a ferrule, the arrangement being such that by use of the machine a tapped hole can both be made in the main pipe, and the ferrule inserted into the hole through the open valve.

Preferably the valve has a ball-shaped valve member through which is a fluid-flow passage that is aligned with the said open lower end and the spindle in the valve-open position.

A machine according to the invention with a valve having a ball-shaped valve member has the advantage over known ferrule fixing machines that a ball-valve can more easily be opened and closed under pressure than the gate valves used in existing machines in which a capillary tube connection is necessary by-passing the main valve to equalize the pressures on opposite sides of the valve before the slide can be moved. Such capillary tubes usually project on the outside of the body of the machine and are apt to be damaged.

The machine preferably comprises a drain outlet operable from the open lower end of the housing.

The drain outlet could have its own valve but its opening is preferably controlled by the valve of the machine. Preferably the outlet then extends from the fluid-flow passage through the valve member, for example along the axis of rotation of the valve member.

Fluid escapes through the drain outlet when the valve is open (as it must be while the hole is being drilled through it) as soon as the drill breaks through the wall of the main pipe. This waste flow serves to carry away swarf that would otherwise drop into the main as it is being drilled and tapped. The amount of fluid wasted is negligible as flow is restricted among other things by the size of the drain outlet. The waste flow also serves to reduce the pressure within the machine so that the design specification for strength can be reduced. This not only saves expense but makes the machines according to the invention much easier to man-handle into position.

According to this aspect the present invention also consists in a machine for making a connection to a main pipe while the pipe is carrying a fluid under pressure comprising a housing having an open lower end to be closed by the main pipe, means for drilling and tapping a hole in the main pipe exposed to said open lower end and for inserting therein a ferrule, the housing further having a drain outlet openable from the open lower part of the housing, the arrangement being such that by use of the machine a tapped hole can be made in the main pipe and a ferrule fitted therein, and fluid that escapes from the main pipe while the tapped hole is being made can be allowed to flow through the drain outlet.

The present invention further consists in a method of making a branch connection to a main pipe while the pipe is carrying a fluid under pressure comprising the steps of clamping to the outside of the main pipe a drilling and tapping and ferrule-fixing machine having a housing with an open side closed by the main pipe and with a drain outlet therefrom, making by use of the machine a tapped hole in the main pipe exposed in the chamber, fluid that escapes from the main pipe while the hole is being made being allowed to flow through the housing and out through the drain outlet together with any pipe material entrained therein, and fitting the ferrule by use of the machine in the hole so drilled.

Embodiments of the invention will now be described, by way of example only, and with reference to the accompany diagrammatic drawings in which: Figure 1 is a longitudinal section of one form of machine according to the invention, Figure 2 is a fragmentary view similar to part of Figure 1 but showing a different stage in the use of the machine.

Figures 3 and 4 are further fragmentary views on a larger scale but on the same section line as Figure 1 showing further stages in the use of the machine, Figure 5 is a front view of a modified machine, and Figure 6 is a section on line VI-VI of Figure 5.

The machine of Figures 1 to 4 is supported on a main water pipe 1 by means of a separate saddle 2 which includes a bolt-on clamp 3, of appropriate size for the main pipe, for securing the machine to the main pipe 1. The machine has a tubular housing 4 comprising a valve body 5 and a spindle carrier 6 detachably mounted on the valve body 5 by an external screw-thread 7 on the spindle carrier which engages a complementary screw-threaded socket 8 at the top of the valve body. The lower end of the valve body is a threaded fit in a collar 9 of the saddle 2. The threaded connection formed by the screwthreads 7 and 8 is of the knuckle or round thread type with a greater pitch than the threaded fit of the collar 9 in the collar 9 of the saddle 2 so that it can be released more easily to allow removal of the spindle carrier 6 without loosening the valve from the saddle.Lugs 10 are provided on the spindle carrier 6 to assist release. Alternatively a joint of the boyonet or other similar type may be used between the spindle carrier 6 and the valve body 5.

Within the valve body is rotatably mounted a ballshaped valve member 11 with a diametral fluidflow passage 12 which in the open position of the valve is aligned with an inlet opening 13 forming an open lower end of the tubular housing 4 and open through a hole 14 in the saddle 2 to the wall of the main pipe 1 which thereby closes the open lower end of the tubular housing 4. The passage 12, opening 13 and hole 14 are all of the same diameter.

A seal is required between the saddle 2 and the main pipe 1 around the hole 14. As alternatives, an O-ring seal 38 in a groove in the saddle 2 is shown on the right-hand side of Figure 1 and a plain gasket 37 on the left-hand side.

The valve member is rotatable about an axis 15 by a drive shaft 16 which at its inner end has a diametral rib 17 (see Figure 4) to engage a chordal groove in the surface of the valve member 11,so keying the valve member to turn with the drive shaft. Close to the rib 17 the drive shaft 16 has an annular flange 18 to engage a counterbore at the inner end of a bore through the valve body wall in which the drive shaft is journalled. Engagement of the annular flange 18 with the counterbore keeps the rib 17 in engagement with the groove in the valve member. An O-ring seal 18 prevents fluid leakage along the shaft 16. The drive shaft 16 extends from the valve body and is fitted with an operating arm 20 for turning the valve member.

On the side opposite the drive shaft 16 a drain outlet 21 extends along the axis of rotation 15 through the valve member 11 and the wall of the valve body 5 from the passage 12. A hose connection 22 is provided at its outer end.

Atool-carrying assembly 24 is rotatably mounted within the spindle carrier 6 and comprises a central spindle 25 with a tool holder 26 at its lower end and a sleeve 27 within which the spindle 25 is rotatably supported and which is threaded in the spindle carrier by a lead screw so that the sleeve 27 and spindle 25 can be advanced axially through operation of a ratchet 29 that rotates the sleeve 27 while the spindle 25 is rotated to drill and tap a hole, or insert a ferrule into a tapped hole, in the main pipe. A thrust washer 23 is fitted between the tool holder 26 and the lower end of the sleeve 27, its periphery being surrounded by the spindle carrier. The thrust washier 23 may be of resilient material such as nylon or other suitable plastics.The tool holder 26 has a taper socket (see Figure 3) to receive a shank of a combined drill and tap 34 (Figure 1) or a shank 30 of an adaptor 31 having a screw threaded nose 32 to support a ferrule 33.

In use, for example on a main water pipe, the machine with a combined drill and tap 34 in the tool holder 26 is mounted on the main pipe and the valve member 11 moved to the open position. The drill and tap 34 is advanced through the passage 12 as shown in Figure 1 and a hole is drilled in the main pipe. When the drill 34 breaks through the wall of the pipe, water begins to flow through the opening 13 and the passage 12 to the drain outlet 21 carrying with it to waste swarf from the drilling and tapping operation, which would otherwise drop into the main. As the drain outlet is of limited size the flow of waste water is restricted but is sufficient to reduce the water pressure in the valve body considerably below that within the main water pipe. This reduced pressure reduces the load applied to the thrust washer below that in known machines and so enables a plain washer of nylon or other suitable material to be used. The fluid pressure compresses the washer 23 which is of thick resilient material axially and expands it radially against the wall of the spindle carrier 6 so that is erves also as a gland restricting leakage along the lead screw 28. The drill and tap 34 is then withdrawn through the valve member 11 and the valve member is closed as shown in Figure 2, the spherical sealing surface of the valve member closing the opening 13. The waste water flow through the drain outlet 21 is thereby shut off. The spindle carrier 6 is then removed from the valve body 5 and the drill and tap replaced by a ferrule 33 using the adaptor 31 as shown in Figure 3.

The spindle carrier 6 is re-assembled on the valve body 5, the valve member 11 moved to the open position again and the ferrule 33 on the tool holder 26 advanced through the passage 12 and screwed into the tapped hole (Figure 4). As the ferrule engages the tapped hole with a taper thread it is gripped sufficiently tightly for the ad pator 31 to be unscrewed from the ferrule by reverse rotation of the spindle 25. The machine can then be removed from the main leaving the ferrule in place.

The modified form of machine illustrated in Figures 5 and 6 is similar to that of Figures 1 to 4 except that, instead of being supported on the main pipe by a bolt-on saddle it is clamped to the pipe by a chain or strap 35 that passes around the main pipe 1.

A resilient gasket 35 is provided between the valve body 5 and the main pipe 1 to form a water seal. The gasket is adapted so that it will resiliently conform to a range of main pipe sizes, thereby avoiding the need to provide a different gasket for each main pipe size. The gasket 36 may be hollow and filled with an inert gas such as nitrogen.

Claims

1. A machine for making a connection to a main pipe while the pipe is carrying a fluid under pressure comprising a tubular housing having an open lower end to be closed by the main pipe, a valve which is rotatably mounted within the housing having a valve member with a sealing surface which lies on a sphere to close a flow path through the housing from the said lower end, and an upper end that rotatably supports a removable spindle which can carry either a drilling and tapping tool or a ferrule, the arrangement being such that by use of the machine a tapped hole can both be made in the main pipe, and the ferrule inserted into the hole through the open valve.

2. A machine according to claim 1 wherein the valve has a ball-shaped valve member through which is a fluid-flow passage that is aligned with the said open lower end and the spindle in the valveopen position.

3. A machine according to claim 1 or claim 2 comprising a drain outlet openable from the said open lower end of the housing.

4. A machine according to claim 3 wherein the drain outlet extends from a, or the, fluid-flow passage through the valve member.

5. A machine according to claim 4 wherein the drain outlet extends along the axis of rotation of the valve member.

6. A machine for making a connection to a main pipe while the pipe is carrying a fluid under pressure comprising a housing having an open lower end to be closed by the main pipe, and means for drilling and tapping a hole in the main pipe exposed to said open lower end and for inserting therein a ferrule, the housing further having a drain outlet operable from the open lower part of the housing the arrangement being such that by use of the machine a tapped hole can be made in the main pipe and a ferrule fitted therein, and fluid that escapes from the main pipe while the tapped hole is being made can be allowed to flow through the drain outlet.

7. A machine according to claim 6 wherein the housing is tubular and there is within the housing a valve to close a flow path through the housing from the said lower end, having in the open position a straight through flow path, the housing having an upper end that rotatably supports a removable spindle which can carry either a drilling and tapping tool or a ferrule, the arrangement being such that by use of the machine the tapped hole can both be made in the main pipe and the ferrule inserted into the hole through the open valve.

8. A machine according to claim 6 wherein the valve has, to close the flow path, a valve member with a sealing surface which lies on a sphere.

9. A machine according to claim 8 wherein the valve has a ball-shaped valve member with a through, fluid-flow passage that is aligned with the open lower end and the spindle in the open position.

10. A machine according to any one of the preceding claims 6 to 9 wherein the drain outlet extends from a, or the, fluid-flow passage through the valve member.

11. A machine according to any one of preceding claims 6 to 10 wherein the valve member is rotatably mounted and the drain outlet extends along the axis of rotation of the valve member.

12. A machine according to any preceding claim wherein the tubular housing comprises a valve body and a spindle carrier detachably mounted on the valve body for removal of the spindle.

13. A machine according to claim 12 wherein the spindle carrier is detachably mounted on the valve body by screw-threaded engagement of the spindle carrier with the valve body.

14. A machine according to claim 13 wherein the screw-threaded engagement is an easy fit and has a thread of the knuckle or round thread type.

15. A machine according to any preceding claim wherein the lower end of the tubular housing screw-engages a separate saddle for mounting the machine on the main pipe.

16. A machine according to claims 14 and 15 wherein the knuckle or round thread screw-threaded engagement is of coarser pitch than the thread by which the tubular housing screw-engages the saddle.

17. A machine according to any one of preceding claims 1 to 14wherein the tubular housing has an integral saddle for mounting the machine on the main pipe.

18. A machine according to any preceding claim comprising means for clamping the machine on the main pipe.

19. A machine according to any preceding claim comprising a flexible pad between the tubular housing or the saddle and the main pipe, the pad having an opening through which the open lower end of the housing can be exposed to the pipe and being capable of conforming to a range of pipe sizes when the machine is clamped to the pipe.

20. A machine according to any preceding claim wherein a plain thrust washer of resilient material is provided to resist axial load on the spindle, the periphery of the thrust washer being surrounded by the tubular housing, the arrangement being such that, in use fluid pressure acting axially on the spindle causes the thrust washer to expand radially against the tubular housing so as to serve as a gland rstricting leakage from the upper part of the tubular housing.

21. A method of making a branch connection to a main pipe while the pipe is carrying a fluid under pressure comprising the steps of clamping to the outside of the main pipe a drilling and tapping and ferrule-fixing machine having a housing with an open side closed by the main pipe and with a drain outlet therefrom, making by use of the machine a tapped hole in the main pipe exposed in the chamber, fluid that escapes from the main pipe while the hole is being made being allowed to flow through the housing and out through the drain outlet together with any pipe material entrained therein, and fitting the ferrule by use of the machine in the hole so drilled.

22. A method of making a branch connection to a main pipe while the pipe is carrying a fluid under pressure by use of a machine according to claim 3 or claim 6 or any one of claims 4, 5 and 7 to 20 as appendantto claim 3 or claim 6.

23. A machine for making a connection to a main pipe while the pipe is carrying a fluid under pressure substantially as described herein with reference to and as illustrated by Figures 1 to 4 of the accompanying drawings.

24. A machine for making a connection to a main pipe while the pipe is carrying a fluid under pressure substantially as described herein with reference to and as illustrated by Figures 1 to 4 as modified by Figures 5 and 6 of the accompanying drawings.

25. A method of making a connection to a main pipe substantially as described herein making use of a machine as claimed in claims 23 or claim 24.

26. A branch connection to a main pipe made by the machine or method of any of the preceding claims.