METHOD AND APPARATUS TO LINE PIPE HOMOGENEOUSLY FIELD OF THE INVENTION

[0001] The present invention relates to pipe lining, and more particularly a pipe lining method and apparatus to line a pipe homogeneously throughout.

BACKGROUND

[0002] After gas and liquid transport pipes are cleaned and prepared (ie tubercules are removed, tar and bitumen and minimalized, leaks are detected and serviced, debris is removed), it is ideal to line them. Since bare metal corrodes over time, lining extends a pipe's life span.

[0003] Liners are typically liquid polymers of varying viscosity. The polymers eventually gel, solidify, or harden, over time. After that time, the pipes are reintroduced to service.

[0004] Conventional methods for applying polymer lining to pipes, like US5,873,390,

US8,359,996, US5590689, US5447664, and USUS4397890 are known. These methods involve pushing a liquid polymer block or plug through pipes, essentially wiping the lining onto the pipe.

[0005] Problems with conventional methods also include not being navigable around bends, and unable to account for service connections. [0006] These conventional methods also involve wall contact (at the plug's ends).

[0007] It is possible to blow liquid lining through a pipe (using compressed air), but lining tends to quickly pool at the pipe bottom. Lining shadows (meaning patches of decreased lining thickness) also form within the pipe, making for non-uniform pipe-lining. Shadows often form astern service connections, pipe elbows, and mal-aligned pipe joints.

[0008] The present is an improvement over conventional methods.

DRAWINGS

[0009] FIGURE 1 is a cut-away perspective of a pipe with service connection requiring lining.

[0010] FIGURE 2 is a cut-away perspective the pipe in FIGURE 1 subjected to a gas stream with pooling liquid liner.

[0011] FIGURE 3 is a cut-away perspective of the pipe in FIGURE 1 having a pooled liquid liner.

[0012] FIGURE 4 is a cut-away perspective of the pipe in FIGURE 1 having a

distributive body (shown as an orb) to displace and distribute liquid liner along the pipe wall.

[0013] FIGURE 5 shows three differing non-orb distributive body embodiments in both perspective and plan views. DETAILED DESCRIPTION

[0014] In one embodiment the present forces liner to line the pipe inside wall by displacement and distribution.

[0015] In another embodiment it is a method to pass a distributive body through a pipe interior to displace and distribute liquid liner.

[0016] The present invention is best wholly illustrated in FIGURE 4.

[0017] FIGURE 4 shows a pipe 10 in cut-away section, having an interior wall 20, a first

30 and second 40 end, and a unidirectional gas stream 50. The gas stream 50 streams from the first 30 toward the second 40 end.

[0018] In one embodiment, after the gas stream 50 has been initiated, liquid liner 60 is introduced into the pipe 10. Depending on liner 60 viscosity, the liner 60 may pool along the pipe 10, as shown in FIGURE 2. The liner 60 is generally propelled from the first 30 toward the second 40 pipe end, as shown in FIGURE 3.

[0019] At this stage, the liner 60 is not yet uniformly applied throughout the pipe 10 interior from pipe 10 top to bottom.

[0020] A distributive body 70 is then introduced into the pipe 10. FIGURE 4 shows the distributive body 70 as an orb. In an orb configuration, the orb must have a spherical diameter smaller than the pipe 10 longitudinal diameter.

[0021] By having a smaller diameter, the pipe gas stream 50 is able to stream past the distributive body 70, even though some of the gas stream 50 is temporarily partially obstructed.

[0022] Where the distributive body 70 differs in shape (from orb), such as the exemplary embodiments shown in FIGURE 5, the distributive body 70 is sized smaller than the pipe diameter, sufficient to partially obstruct the gas stream 50.

[0023] As the gas stream 50 encounters the distributive body 70, the gas stream 50 speeds up, and the gas pressure local to the distributive body lowers.

[0024] Once the gas stream 50 has cleared the distributive body 70, the gas stream 50 slows to its prior speed, and the gas pressure increases to its previous level.

[0025] The gas stream 50 obstruction results in radial outward displacement and distribution of the liner 60. As a result, the liner 60 in the gas stream 50 produces a complete and uniform 360 degree coat.

[0026] In a specific configuration, the gas stream 50 propels the distributive body 70 forward, from the first 30 toward the second 40 pipe end. In this configuration, the

distributive body 70 is not tethered to either of the first 30 or second 40 pipe end.

[0027] In alternate configurations, the distributive body 70 may be tethered at either pipe 10 end, for feeding out or pulling the distributive body 70 accordingly.

[0028] As the distributive body 70 moves through the pipe 10 from one end 30 to the other 40, it comes upon and compresses pooled liner 60. On and near compression, and in the presence of the gas stream 50, the pooled liner 60 also rides up the pipe wall 20 to improve wall 20 coating homogeneity.

[0029] Distributive bodies 70 like those in FIGURE 5 (conical, cylindrical, and elliptical prism respectively), when tethered to a pipe end 30, 40, might not rest on the pipe 10 bottom, and so might not compress the pooled liner 60. They might instead displace radially inward, when in a gas stream 50, causing radially outward liner 60 displacement (previously described).

[0030] The upward force from the gas stream 50 passing the distributive body 70 ensures liner 60 reaches the top of the pipe 10, to form a uniform coating / lining.

[0031] As the distributive body 70 passes from the first 30 toward the second 40 end, the liner adheres to the pipe wall 20 as generally shown by arrow 90.

[0032] As a result, the liner 60 does not have to be scraped or sponged along the pipe wall 20, as it does in the prior art. Also, instead of a pushing or pressure based system, as in the prior art, the present provides a stream based system. Liner 60 is aerodynamically flown and directed within the pipe 10, to ensure homogenous coating, even at service connections 100 and pipe joints 110.

[0033] If for any reason liner 60 has been introduced into the pipe 10 prior to streaming the unidirectional gas stream 50, the liner 60 can still be made to line the pipe wall 20 from top to bottom by placing into the pipe 10, the distributive body 70 and thereafter commencing gas streaming 50.

[0034] The distributive body 70 can be moved to any location required within the pipe

10, via the gas stream 50 propulsion (where the distributive body 70 is light enough, and untethered) or by a combination of feeding and pulling (where the distributive body 70 is tethered) and gas stream 50 propulsion.

[0035] Liner 60 curing / drying can be accelerated by supplying a heated gas stream 50.