GB2142700A - Apparatus for drilling apertures in conduits - Google Patents

Abstract

Apparatus for tapping a main conduit (2, Fig. 1) and establishing fluid communication with a branch conduit (3, Fig. 1) attached to a stub conduit (1, Fig. 1) comprises a tubular member 12 having an external screw thread 13 connectable to a valve (4, Fig. 8) mounted on the stub, a sleeve 14 screw threadedly mounted on the tubular member and displaceable relative thereto, and a shaft 18 coaxially disposed within the tubular member. The shaft has a drilling tool 20 at one end and a handle 21 at the other end, and is also formed with spaced apart collars 24 which cooperate with annular supports 25 to determine the axial position of the shaft relative to the sleeve, the supports being retained in seat 22 by ring nut 23. After drilling is completed the shaft is withdrawn and the tool is replaced with a plug (5, Fig. 8) which blanks off the stub, enabling the valve to be removed and reused. <IMAGE>

Description

SPECIFICATION An apparatus for drilling or boring aper tures in conduits used for carrying pressur ised fluids The present invention relates to an apparatus for drilling or boring apertures in conduits used for carrying pressurised fluids, such as gases.

Various apparatuses for drilling or boring apertures in conduits carrying pressurised fluids when it is necessary to divert the fluid flow from a main conduit into a branch con duit are already known.

In general, a stub-conduit carrying the branch conduit is welded to the main conduit but the two conduits remain to be placed in fluid-flow communication with one another.-A valve is then screw-fitted onto the stub-con duit.and the.drilling or boring device is then screw-fitted onto the valve. Whilst the drilling is taking place, the valve is opened so that a toolholder shaft of the apparatus can extend through the valve and through the hollow interior of the stub-conduit to reach the con duit to be drilled or bored. Once the aperture has been formed, the shaft with the drilling or boring tool attached thereto is withdrawn, the valve is closed and the apparatus removed.

In these known arrangements, the valve remains permanently affixed to the tubular stub-conduit to close it and to prevent pressur ised fluid from escaping while still permitting it to pass into the branch conduit.

Apparatuses of this known type have vari ous disadvantages of practicality operation and #speed of use and also have the disadvan tage that the valve cannot be removed from the tubular stub-conduit for subsequent re use. The costs inherent in the formation of a branch conduit from a main conduit are appreciably increased by this disadvantage.

The present invention therefore seeks to provide an apparatus for drilling or boring apertures in conduits which is relatively sim ple and speedy to use and which also makes it possible for a screw-threaded plug to be fitted to the tubular stub-conduit so that the valve may be removed and re-used after the aperture has been formed in the main conduit and the branch conduit has been brought into fluid-flow communication therewith.

According to the present invention, there is provided an apparatus for drilling or boring an aperture in a main conduit carrying pressur ised fluid to permit the flow to be diverted into a branch conduit attached to a tubular stub-conduit, the stub-conduit having been pre-welded to the main conduit in the region in which the bore is to be produced, the apparatus comprising a tubular member pro vided with an external screw-thread, one end of the external screw-thread being connectable to the body of a valve mounted on the stubconduit, a sleeve member which is screwthreadedly mounted on the tubular member and is displaceable relative thereto and a shaft located within and extending along the axis of the tubular member and the sleeve member, the shaft being provided at one of its ends with a drilling tool and at its opposite end with an actuating handle, wherein the shaft has a plurality of spaced-apart collars formed therein, a seat recess concentric with the shaft and capable of being closed by means of a ring nut is screw-fitted onto the sleeve at its end adjacent the actuating handle, the shaft being axially displaceable so as to cause the tool to be displaced into the area in which the boring or drilling is to be effected and to cause one of the collars to be located substantially at the level of the seat, and an annular support capable of fitting in the seat is provided, the support being securable in position by means of the ring nut so that the shaft is axially secured to the sleeve but is capable of rotation therein, the annular support being formed of two half-members which are inserted from opposite sides into the collar located substantially at the level of the seat.

Preferably, the drilling tool is mounted on the shaft by means of a toolholder, the toolholder being capable of making a connection with, supporting and screwthreading a threaded plug into the tubular stub-conduit attached to the main conduit carrying the pressurised fluid, the stub-conduit having an internal screw-thread which engages with the screw-threaded plug so as to close the stubconduit and to permit the valve fitted to the stub-conduit during the drilling operation to be removed.

Desirably, the shaft is axially displaceable within the sleeve member and the tubular member independently of the tubular member, the shaft being axially secured by means of the bipartite annular support, the shaft being rotatable independently but being axially displaceable with the sleeve member in order to advance while the operations of drilling the conduit and threading the screwthreaded plug into the tubuar sub-conduit are being effected.

The invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a perspective view of a hole-boring apparatus in accordance with the present invention detachably mounted on a side-arm conduit which is to be placed in fluid flow communication with a main conduit; Figure 2 is a cross-sectional view of the main and side-arm or sub-conduits shown in Fig. 1; Figure 3 is an axial cross-sectional view of the apparatus shown in Fig. 1; Figure 4 is a transverse cross-sectional view taken along the line IV-IV of Fig. 3; Figure 5 is a detailed view of an annular support for axially positioning a toolholder shaft, both the support and the shaft-forming part of the apparatus shown in Fig. 1;; Figures 6, 7 and 8 show similar axial views, all partially in section, of the apparatus shown in Fig. 1 in the positions in which it occupies when a valve is being fitted to the side-arm or stub-conduit, when the hole is being bored in the main pipe and when a plug is being fitted to the side-arm or stub-conduit respectively; and Figure 9 is a cross-sectional view showing the main conduit in fluid flow communication with the side-arm or stub-conduit after the hole-boring operation has been effected.

In the drawings, there is shown a tubular side-arm or stub-pipe 1 which has been attached by welding to a main conduit 2 in the region 2' of this latter in which the fluid flow communication between the conduits 1 and 2 is to be established. The conduit 2 carries the pressurised fluid. The conduit 2 includes a branch conduit 3 through which the pressurised fluid will flow once the connecting bore has been formed in the conduit 2.

The stub-conduit 1 is provided with an external screw-thread 10. The free end of this screw-thread is used for the attachment thereto of a valve 4 such as a ball valve. The pipe 1 also has an internal screw-thread 11 to which a plug 5 may be attached to seal the stub-conduit 2 and to enable the valve 4 to be removed.

For drilling the portion 2' of conduit 2, the present invention provides an apparatus which comprises, as shown in Figs. 1 and 3, a tubular member 12 having an external screwthread 13 along which a sleeve 14 having a corresponding internal thread 14' can be displaced. The tubular member 12 also has a further screw-threaded portion 15 at its lower end which is capable of engaging a complementary portion of the body of the valve 4 or, if desired, an interposed connecting member.

An axial bore 16 is provided in the tubular member 12, which bore houses a rotatable shaft 18. The shaft 18 is axially displaceable either independently of, or in association with the sleeve 14 and is sealed by means of seals 17. The lower end of the shaft 18 is fitted with a toolholder 19 capable of carrying a circular cutter device 20. The upper end of the shaft projects through the sleeve 14 and is connected to a handle member 21 by means of which it is rotated.

A seat member 22, which can, if desired, be closed off by means of a ring nut 23, is screw-fitted onto the sleeve 14. The member 22 has an aperture formed therein which permits the passage of the shaft therethrough.

This aperture is provided at the upper end of the sleeve 14 and is concentric with the shaft 18.

Collars 24 are formed at spaced intervals along the length of the shaft 18, a desired one of such collars being selectively engaged by an annular support. The support is formed of two opposing semi-circular members 25.

The support 25 is designed to sit on the seat 22 at the upper end of the sleeve 14 and is secured in position by a ring nut 23. The shaft is thus supported and axially secured.

The sleeve 14 is provided with radially extending handle members 26, rotation of which causes rotation of the sleeve on, and with respect to, the tubular member 12. Accordingly, once the shaft 18 has been axially secured by the annular support 25, the advance and return of the cutter device 20 is ensured.

The hole-boring or drilling process will now be described. Initially, the valve 4 is fitted onto the external screw-thread 10 at the upper end of the tubular stub-conduit 1. The tubular member 12 of the apparatus is then screw-threaded onto the valve 4 by means of the portion 15. When the valve 4 has been opened, the shaft 18 is axially displaced until the cutter device 20 makes contact with the portion 2' where the hole is to be bored in the conduit 2. The two halves of annular support members 25 are then inserted into the collar portion 24 in the shaft closest to the seat or recess 22 in the sleeve. Once the annular support 25 has been seated in the seat 22, it is secured by means of the ring nut 23 so that the shaft 18 is axially connected to the sleeve 14 even though it is supported and is free to rotate.

The bore in the conduit 2 is then produced, as shown in Fig. 7 by rotating the shaft 18 by means of the handle members 21 and by simultaneously advancing the sleeve 14 by its screw-thread on the tubular member 12.

When the bore in the conduit has been formed the shaft 18 is withdrawn, utilising the sleeve 14, until the tool 20 is located above the opening of the valve 4. The valve 4 is then closed to prevent the escape of fluid, the ring nut 23 is released and the shaft is unscrewed to remove the cutting tool 20. The tool 20 is replaced by the plug 5 which is designed to seal the tubular stub-conduit 1.

By repeating the same operations utilised to form the bore after the valve 4 has been opened, the plug 5 is screwed onto the internal thread 11 of the stub-conduit 1 as is shown in Figs. 8 and 9 in the drawing.

To permit the threaded plug 5 to be screwed into position, the toolholder 19 on the shaft 18 is provided with pins 27 and, in the centre, with a member 18 which engagesin an aperture formed in the plug and can be released therefrom once the plug has been located in position.

When the plug 5 has been screw-fitted into the stub-conduit 1, the connection of the branch conduit 3 in fluid flow communication with the main conduit 2 has been effected.

The apparatus may then be removed from the valve 4 and the valve, in turn, can be removed from the stud-conduit 1 for later re-use if desired without adversely affecting the effectiveness and safety of the seal of the connection.

The apparatus may also be used for drilling or boring holes in conduits carrying unpressurised fluids, in which case it is not necessary to use a valve.

Claims (4)

1. An apparatus for drilling or boring an aperture in a main conduit carrying pressurised fluid to permit the flow to be diverted into a branch conduit attached to a tubular stub-conduit, the stub-conduit having been pre-welded to the main conduit in the region in which the bore is to be produced, the apparatus comprising a tubular member provided with an external screw-thread, one end of the external screw-thread being connectable to the body of a valve mounted on the stubconduit, a sleeve member which is screwthreadedly mounted on the tubular member and is displaceable relative thereto and a shaft located within and extending along the axis of the tubular member and the sleeve member, the shaft being provided at one of its ends with a drilling tool and at its opposite end with an actuating handle, wherein the shaft has a plurality of spaced-apart collars formed therein, a seat recess concentric with the shaft and capable of being closed by means of a ring nut is screw-fitted onto the sleeve at its end adjacent the actuating handle, the shaft being axially displaceable so as to cause the tool to be displaced into the area in which the boring or drilling is to be effected, and to cause one of the collars to be located substantially at the level of the seat, and an annular support capable of fitting in the seat is provided, the support being securable in position by means of the ring nut so that the shaft is axially secured to the sleeve but is capable of rotation therein, the annular support being formed of two half-members which are inserted from opposite sides into the collar located substantially at the level of the seat.

2. An apparatus as claimed in claim 1, wherein the drilling tool is mounted on the shaft by means of a toolholder, the toolholder being capable of making a connection with, supporting and screw-threading. a threaded plug into the tubular stub-conduit attached to the main conduit carrying-the pressurised fluid, the stub-conduit having an internal screw-thread which engages with the screwthreaded plug so as to close the stub-conduit and to permit the valve fitted to the stubconduit during the drilling operation to be removed.

3. An apparatus as claimed in claim 1 or 2, in which the shaft is axially displaceable within the sleeve member and the tubular member independently of the tubular member, the shaft being axially secured by means of the bipartite annular support, the shaft being rotatable independently but being axially displaceable with the sleeve member in order to advance while the operations of drilling the conduit and threading the screwthreaded plug into the tubular stub-conduit are being effected.

4. An apparatus for drilling or boring an aperture in a conduit as claimed in claim 1 constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.