Method of sealing an outlet opening

• US 5,740,829 A
• Filed: 07/25/1995
• Issued: 04/21/1998
• Est. Priority Date: 07/26/1994
• Status: Expired due to Fees

• Current Assignee: British Gas Trading Limited (Centrica PLC)
• Original Assignee: British Gas Trading Limited (Centrica PLC)
• Inventors: Jacobs, Michael, Johnson, Leigh Martin
• Primary Examiner(s): Walton, George L.
• Application Number:
  US08/506,609
• Time in Patent Office: 1,001 Days
• Field of Search: 137/15, 137/315, 137/317, 137/318, 137/242, 138/89, 138/94, 138/97, 15/104.03, 15/104.05, 15/104.09, 15/104.16, 29/281.1, 29/281.5, 29/281.6, 29/464, 228/49.1, 228/49.3, 269/41
• US Class Current: 137/15.08
• CPC Class Codes: F16L 41/04 Tapping pipe walls, i.e. making connections through the walls of pipes while they are carrying fluids; Fittings therefor
• CPC Class Codes: F16L 55/10 Means for stopping flow from or in pipes or hoses F16L29/00, F16L37/28 take precedence; valves F16K
• CPC Class Codes: F16L 55/18 Appliances for use in repairing pipes F16L55/10 takes precedence
• CPC Class Codes: Y10T 137/0441 Repairing, securing, replacing, or servicing pipe joint, valve, or tank
• CPC Class Codes: Y10T 137/0475 Having deformable or inflatable means
• CPC Class Codes: Y10T 137/4273 Mechanical cleaning
• CPC Class Codes: Y10T 137/6123 With aperture forming means
• CPC Class Codes: Y10T 29/49895 Associating parts by use of aligning means [e.g., use of a drift pin or a "fixture"]
• CPC Class Codes: Y10T 29/53978 including means to relatively position plural work parts

Abstract

An outlet opening (14) to a branch line 40 in a pipeline 10 is sealed without interrupting the flow of gas in the pipeline 10 by cutting an access opening 60 in the wall 62 of the pipeline 10 opposite the branch line 40. A seal 100 is inserted through the access opening 60 using a sub-assembly 70, which consists of a flange 74 having a screw-threaded through aperture, an externally screw-threaded tube 82 received in the aperture and a rod 80 carrying a handle 72 at one end and the seal 100 at the other. The seal 100 has a sealing face 102 which is part-cylindrical in shape and is held in the correct orientation by the handle 72 while the tube 82 is screwed home. When work on the branch line 40 has been completed a temporary seal 160 is installed in the joint-flange 16 which is welded to the pipeline 10 allowing removal of the isolation valve 64 which is replaced by a blanking flange fitted to the joint-flange 16.

Claims

1. A method of sealing an outlet opening to a branch line in a pipeline by applying a seal to the outlet opening from inside of the pipeline, said branch line being in fluid communication with said pipeline, the method comprising the steps of welding a joint-flange to the pipeline opposite to the branch line, using a jig to locate said joint-flange in relation to the pipeline so as to facilitate the welding of the joint-flange in the correct position, cutting an access opening through the wall of the pipeline opposite and in alignment with the outlet opening, inserting the seal into the pipeline through the access opening and applying the seal solely across the outlet opening interiorly of the pipeline so as to block communication between said branch line and said pipeline.

2. A method according to claim 1, wherein the seal is composed of synthetic plastics material.

3. A method according claim 1, wherein the seal has a sealing face which is of part-cylindrical shape, the radius of curvature of said face matching the radius of curvature of the inside wall of the pipeline.

4. A method according claim 1, wherein said seal is mounted at one end of a rod inserted through a hollow externally screw threaded tube, which is screwed through an internally screw threaded flange plate secured on an isolation valve secured on the joint-flange, the rod being prevented from rotating while the tube is screwed to advance the seal into position.

5. A method according claim 1, wherein prior to applying the seal, the inside wall of the pipeline around the outlet opening is brushed by a brush inserted through the access opening.

7. A method according to claim 1, when work on the branch line has been completed, locating a closure plug in the joint-flange, removing the isolation valve and fitting a blanking flange to the joint-flange.

8. A method according to claim 1, comprising the following steps:

(i) welding a joint-flange to the pipeline opposite to the branch line using said jig to locate the joint-flange before it is welded;

(ii) fitting an isolation valve to the joint flange;

(iii) fitting a drilling machine to the isolation valve;

(iv) using the drilling machine to cut an access opening in the wall of the pipeline opposite to the outlet opening;

(v) removing the drilling machine;

(vi) fitting an insertion rod sub-assembly to the isolation valve;

(vii) using the sub-assembly to brush the inside wall of the pipeline around the outlet opening;

(viii) using the sub-assembly to position and apply a seal to the outlet opening;

(ix) removing the sub-assembly;

(x) locating a closure seal in the joint-flange;

(xi) removing the isolation valve; and

(xii) fitting a blanking flange to the joint-flange.

6. A method according to claim 6, wherein the brush is mounted at one end of a rod inserted through said access opening.