GB2198208A - Access gland for pipe wall - Google Patents

Abstract

A gland is of the type permitting a TV camera and cable to be fed into a gas main by way of a hole drilled in the wall of the main. The gland 1 has a base 2 adapted for mounting the gland 1 on a gate valve 3 which itself is mounted on the main 35 over a hole 37 drilled in the main 35 and a tube 5 communicating with the base 2 through which tube 5, the camera 40 and cable is inserted. The tube 5 extends from a plate 4 which is rotatably mounted on the base 2. Rotation of the plate 4 causes the tube 5 to vary its position between a first position where the axis of the tube 5 is substantially at right angles to the axis of the main 35 and a second position where the axis of the tube 5 is at an acute angle to the axis of the main 35. <IMAGE>

Description

GLAND This invention relates to a gland of the type permitting a member to be fed into a fluid-carrying pipeline by way of a hole in the wall of the pipeline.

Glands of the above type are used in the gas industry to permit an operative to gain access to the inside of a gas main for inspection or repair purposes at a point close to the desired site of inspection or repair while maintaining gas flow through the main at all times.

These glands permit the operative to feed a TV inspection camera and attached cable or the like into the gas main through a convenient hole drilled in the wall of the main while preventing gas escaping from the hole since the cable is fed through a seal mounted in the gland.

In use the gland is sealingly mounted on a known type gate valve which itself is mounted on the wall of the pipeline over the hole which has been previously drilled using a hole saw assembly in combination with the gate valve. When open, the gate valve provides an aperture for the TV camera or other member.

One such type of gland comprises a base which is adapted for detachable mounting to the gate valve and a pair of insertion tubes extending from the base for receiving the cable to be fed into the main. The tubes which contain the rubber seals are so arranged that in use of the gland with the gate valve the axis of the tubes lie at equal but opposite acute angles to the axis of the main.

By angling the tubes in this way the cable can be fed in the appropriate direction along the pipeline by inserting it through the appropriate tube by way of the gate valve and the hole in the wall of the main.

One problem with a gland of this type is that since the aperture in the gate valve and the hole in the wall of the main are at an acute angle to the axis of each tube, a smaller orifice diameter is presented for the introduction of TV cameras and other articles in the gas main than there would be if the tube were arranged with its axis at right angles to the aperture of the gate valve and the hole in the wall of the main.

This can seriously restrict the size of the TV camera which can be used with the gland.

It is therefore an object of the present invention to provide a gland overcoming this disadvantage.

According to the present invention we provide a gland of the type permitting a member to be fed into a fluid-carrying pipeline by way of a hole in the wall of the pipeline, the gland having a base adapted for mounting the gland to the wall of the pipeline over the hole and a tube communicating with the base and connected to the base in such a way that in use of the gland the position of the tube relative to the axis of the pipeline can be varied.

An embodiment of the invention will now be particularly described by way of example only with reference to the accompanying drawings in which : Figure 1 shows a side view of the gland in position on a gas main, Figures 2 and 3 are longitudinal sections through the gland in use with a TV camera and cable being fed into the gas main.

Referring to the drawings, the gland 1 comprises a base 2 which in use is mounted in a conventional gate valve 3 and a rotatable plate 4 mounted on the base 2 and from which plate 4 there extends upwardly an insertion tube 5.

The base 2 has a lowermost cylindrical portion 6 detachably received in an inlet portion 7 of the gate valve 3 as is more clearly shown in Figures 2 and 3. A circumferential seal 8 is located in a groove formed between the portions 5 and 6.

The base 2 has an uppermost portion 9 forming a sloping seat for supporting the plate 4 and providing an aperture into the base 2.

The plate 4 has an uppermost circumferential edge 10 which rests upon the uppermost surface 11 of the seat portion 9 and upon which the plate 4 can rotate. The plate 4 has a lowermost circumferential edge 12 located within the wall 13 of the aperture formed by the seat portion 5 and within a recess formed between the edges 10 and 12 there is located an O-ring 14 which in use sealingly engages with the wall 13.

The plate 4 is secured in position by a securing ring 15 attached to the uppermost surface 11 of the seat portion 9, the ring 15 having an internal circumferential portion 16 overlapping the uppermost surface 17 of the plate 4.

The insertion tube 5 has a lowermost end 18 mounted within an aperture in the plate 4 in such a way that in one position of the plate 4 (Figure 2) the axis of the tube 5 is substantially coaxial with that of the base portion 6. A 1800 rotation of the plate 4 about its central axis however, will cause the tube axis to be inclined towards the axis of the base portion 6 (Figure 3).

Rotation of the plate 4 can be effected by means of a handle 19 bolted to the uppermost surface 17 of the plate 4 in a position on the plate 4 substantially diametrically opposite to that of the tube 5.

An internally threaded retaining collar 20 is threadedly secured to the externally threaded uppermost end 21 of the tube 5, the collar 20 in use partially projecting beyond the end of the tube 5. Secured to the retaining collar 20 is a gland seal 22 of known type. The seal 22 comprises a number of metal discs 23,24,25,26 and 27. Adjacent discs are separated from each other by centrally apertured rubber sealing gaskets 28,29,30 and 31 and the discs and gaskets are bolted together to form the seal 22. The lowermost disc 23 is externally threaded for engagement with the internal threads of the collar 20 and in use abuts the end of the tube 5.

The diameter of the central aperture in the gaskets is selected so as to be somewhat smaller than the diameter of the TV camera and/or cable being inserted into the tube 5. This ensures that the gaskets form a seal with the TV camera and/or cable in use at the upper end of the tube 5.

In use of the gland, as a first step in the process for inserting a TV camera and cable into a gas main, the gate valve 3 is mounted on the main 35 as shown in the drawings. The gate valve 3 may be secured to the main 35 by any convenient means such as by a chain 36 looped around the outer wall of the main 35 and having ends secured to the gate valve 3 as shown in Figure 1. A special canopy (not shown) housing a hole saw (not shown) is then fitted to the gate valve 3 and the saw operated to cut a hole 37 through the main 35. With the gate 38 in the gate valve 3 closed the saw canopy is then removed and the gland 1 is then fitted to the gate valve 3 in place of the saw canopy with its tube 5 coaxial with the base 2 or put another way with the tube 5 at right angles to the axis of the main - the position shown in Figure 2.

Next the TV camera 40 and its cable 41 are pushed through the seal 22 into the tube 5 as shown in Figure 2 and eventually into the base 2 of the gland 1. The gate 38 of the plate valve 3 is then moved to the open position to enable the TV camera 40 to pass through the opening 42 in the gate valve 3, thence partially through the hole 37 in the main 35. With the tube 5 in the position shown in Figure 2 the diameter of the hole 37 presented to the TV camera 40 is at its maximum of course.

The plate 4 is then rotated to the position shown in Figure 3 so that the tube 5 assumes the acutely angled position to permit the TV camera 40 and cable 41 to be pushed along the main 35 in the required direction. It will be appreciated that in Figure 3 the TV camera 40 and cable 41 will be moved in the left hand direction along the main 35.

Removal of the TV camera 40 and cable 41 is the reverse of the procedure described.

The gland 1 can be positioned on gate valve 3 such that the tube 5 can be rotated to a position 180C opposite to that shown in Figure 3 to enable the TV camera and cable to be moved along the main 35 in the right hand direction.

It will be appreciated that all things being equal it will be possible to insert larger diameter items into the main using this type of gland than would be possible if glands of the type described in the introduction were used. This is because during insertion of the item into the main the diameter of the hole drilled in the wall of the main is not restricted in any way since the insertion tube has its axis at right angles to the hole.

Claims (4)

1. A gland of the type permitting a member to be fed into a fluid-carrying pipeline by way of a hole in the wall of the pipeline, the gland having a base adapted for mounting the gland to the wall of the pipeline over the hole and a tube communicating with the base and connected to the base in such a way that in use of the gland the position of the tube relative to the axis of the pipeline can be varied.

2. A gland as claimed in claim 1 in which the position of the tube is variable between a first position where the axis of the tube is substantially at right angles to the axis of the pipeline and a second position where the axis of the tube is at an acute angle to the axis of the pipeline.

3. A gland as claimed in claim 1 or claim 2 in which variation of the position of the tube relative to the axis of the pipeline is effected by the rotation of a plate from which the tube extends, the plate being rotatably mounted within a seat in the base.

4. A gland substantially as hereinbefore described with reference to the drawings.