Thursday, October 23, 2014
Pulling more than one pipe at a time through a bore hole as a means of reducing pipeline construction costs seems to be something that is getting more and more common every month. It creates a unique problem though: how do you prevent the pipe sections from damaging one another both during the 'staging' and during the bore itself? Good news: we know how.
They go by many names: bundle bumper sleeves; pipe spacer rings, pipeline doughnuts, pipeline donuts, or any number of other options. We've sold our spacer rings for pipe as small as 4" and for pipe as large as 20". We've sold our spacer rings to be used on a two pipe bore -- and we've sold our bumpers to be used on four pipe bores. There really is no limit.
Monday, October 20, 2014
Corrosion Prevention on Pipe Bends
Coating a pipe bend can be a challenging application. Sometimes, standard heat shrink sleeves will not work without some amount of skill in your installer. Instead of installing normal 11", 17", 24" or 34" wide shrink sleeves and lobster tailing them (as you would here:)
We find it is often simpler, and more technically sound to coat those bends using a heat shrinkable, spiral wrapped product. Good news, we have a couple of options for that application:
First - you can use our WPC100M Tape product. Made from our normal WPC100M, this product is easy to install, forgiving in terms of surface prep and has a long successful use history. Available in just about any custom width; WPC100M Tape is often the ideal choice for pipelines that will operate at elevated temperatures.
A second option is our Flexclad, heat shrinkable tape. Flexclad doesn't have quite as high of a temperature rating as the WPC100M tape, it is rated for use at 50C; but as a specially designed heat shrinkable tape, it utilizes a lower shrink ratio backing with a hybrid mastic/hot melt adhesive sealant to form a homogenous coating over the length of your bend. Sold in 50 feet long rolls, Flexclad also has quite a long use successful use history.
In both cases, we have material on the ground, ready to ship at a moments notice. We understand that pipeline coatings are often the very last things purchased for a pipeline project, and we keep stock accordingly!
Wednesday, October 1, 2014
Heat Shrink Sleeves and Internal PressureCan a heat shrinkable sleeve hold internal pressure? It doesn't come up often, but it is a phone call that I get a few times per year. Maybe someone is looking to repair a spot where a water line has been compromised. Maybe someone is looking to repair significant damage to a PE pipe. I've even seen someone trying to prevent water ingress at a juncture between a concrete coated line and a pipeline.
My standard answer is: well, our heat shrinkable sleeves are not specifically designed to hold internal pressure, they are designed to seal and prevent water or air from getting to the field joint from the outside. But....there have been cases where one of our sleeves was used to hold internal pressure.
First of course, we had to test it. The industry isn't going to accept a product in an application that hasn't been tested...and tested extensively. In this case, we tested our DIRAX product (often called ROCS when it is not used in a directional drilling application). We used an 8" wide DIRAX shrink sleeve and for the sake of this testing, we installed it on a 1.685" OD pipe (smaller than we would normally recommend using a wrap around shrink sleeve on).
1. The pipe was abraded using a wire brush attached to a typical electrical drill. An area slightly wider than eight inches was abraded to insure good adhesion over the entire width of the sleeve.
2. The sleeve was wrapped around the pipe and centered on the pipe joint. Note: The pipe was not pre-heated.
3. The preattached closure strip was heated and pressed down to hold the sleeve during the shrink process.
4. The sleeve was heated in the center and all around the circumference until fully recovered. As the center area of the sleeve was shrunk, the torch was moved circumferentially and toward one end of the sleeve until one side was fully recovered. The same process was repeated toward the opposite sleeve end. Total installation time was approximately five minutes including pipe abrasion.
note: a power wire brush would reduce the abrasion time
Two pipe samples were fitted with an inlet and outlet pipe and valve system along with a pressure gauge.
Test samples were filled with water to a pressure of 11 PSI and held at that pressure for one hour.
After one hour, the pressure was gradually increased until failure.
Sample One: Held a pressure of 11 PSI for one hour with no leaks. Sample one eventually failed at 22 PSI. The failure occurred at the end of the fixture where the end cap was plastic welded to the pipe.
Sample Two: Sample two was found to have a small, almost invisible crack as the sample was pressurized. The area around the crack was abraded. A small "bicycle tube" repair patch was cut from ROCS material and installed over the crack. After cooling, the sample was pressurized to 11 PSI and held for one hour. The sample gradually pressurized until failure at 25 PSI. Failure occurred at the same area as sample one (the pipe end, away from the sleeve).
ConclusionsAn eight inch wide ROCS sleeve is sufficiently wide enough to properly seal the pipe joint at 11 PSI. An eight inch wide sleeve is easily centered on the joint with no special skill. The ROCS sleeve appears to be more reliable than plastic welding. Small "postage stamp" type repairs can be made using rounded patches of ROCS.
The pipe is a bit subject to overheating with a torch during sleeve installation; therefore, protective blankets would be recommended for use during installation. The same protective blankets used to protect coating during pipeline welding would be suitable.