Always use the same pipe grade, fittings, and adhesive on new parts as is in the existing system.
Contacts
Peley Zheng
Jiayisheng Marine provides GRE pipe repairing,technical inspections,upgrading and repair – treatments of scrubbers (new and in service) worldwide by means of mechanical polishing, (pit) corrosion removal, welding,pickling and passivation for material types such as SUS 304, 316 (L) (LN) , 254SMO and all other SS material types. Jiayisheng Marine is a professional company, with extensive knowledge and understanding of scrubbers and GRE pipe reparing ,our customers (mainly ship owners) are fully satisfied with the results.
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It is imperative that the structural integrity of the scrubber and associated pipework is constantly checked for signs of leakage or corrosion. In view of the acidic nature of the scrubber washwater, correct material selection for the scrubber body, pipework, components and accessories, together with good installation, but also very important, maintenance and repair workmanship are critical to avoid subsequent safety issues.
A clean and passive surface finish is crucial to corrosion resistance. Stainless steel is protected from corrosion by its passive layer - a thin, impervious, invisible, surface layer that is primarily chromium oxide. The oxygen content of the atmosphere or of aerated aqueous solutions is normally sufficient to create and maintain ('self-heal') this passive layer. Unfortunately, surface defects and imperfections introduced during manufacturing or caused by aggressive chemical loadings may drastically disturb this 'self-healing' process and reduce resistance to several types of local corrosion.
Our welders are qualified and trained to know skill in performing the Welding Process to comply with the relevant Welding Procedures. Our qualified welders have many years of working experience in the field of welding repairs on corrosion resistant Stainless Steel Alloys and Metal Materials such as:
Normally, repair means cutting out a fitting or a damaged section of pipe and replacing it with new material.
(Caution:Always determine exactly what fluid has been in the piping system. Contact may be harmful to humans. Take necessary precautions.)Always use the same pipe grade, fittings, and adhesive on new parts as is in the existing system.
Do not mix pipe grades.
Inspecting for Potential Causes of Joint Failure
1) For exposed spigot ends, use 80 to 120 grit sand paper or Emery cloth and lightly sand to remove degradation/ contamination. Avoid over-sanding as this may alter the taper angle of the spigot and may result in voids in the bond line. If degradation/contamination is too severe on 1”-16” (25-400 mm) pipe cut off the spigot and scarf a new spigot end.
2) For exposed bell ends (pipe or fittings), sand thoroughly until the entire surface appears fresh.
3) Hand sanding with 40 grit sandpaper is recommended. Use a light sanding operation to prevent changing the taper angle.
When the damaged area in the pipe wall is larger than 2” (50mm) in diameter follow these instructions:
When damage is local (less than 2” long, but more than 2” around the circumference of the pipe), check to see if there is enough flexibility in the system to allow suffcient movement.
It may be possible to use a short pipe spool and two couplings to repair the line.
Cut out the damaged section, prepare the remaining pipe ends (either scarf or taper depending on product and diameter) then install two couplings and a pipe nipple.
This procedure requires suffcient slack in the line to make the final joint by lifting the pipe (or moving the pipe to one side) to engage the bell and spigot joint.
If the line cannot be moved suffciently to install a sleeve coupling spool piece, scarf or taper both ends of the pipe and install flanges.
If it is impossible to taper the pipe in the rack, you can install a new section of pipe by overwrapping the plain cut ends.
(1) Ensure there’s an area large enough for installers to work on both sides and under the pipe. Cut out the damaged section of pipe and measure the gap. Cut a section of good pipe allowing 1 /8” (3 mm) maximum gap on each end.
(2) Sand the ends of the pipe to remove all resin gloss. Align the replacement pipe section and block up all sections to maintain alignment. All sections must be rigid so they will not move during the overwrapping procedure. Tack welds should be used by placing 1” x 2” patches of glass cloth and adhesive spaced at 90o intervals around the pipe. See Overwrapping.
Components for epoxy overwrap are shown in Table 18.
Use a grinder or sander with coarse sandpaper (40 grit or less) to remove loss 5” (125 mm) on either side of the joint.
Once the adhesive and hardener have been mixed and reacted, nothing can be extracted, and it is classified as non-hazardous material. Dispose of in a normal manner as other solid waste.
Excess adhesive and hardener can be mixed, allowed to react, and disposed of as above.
If extra jars of adhesive or hardener have accumulated without the other component, contact us.
Hardener jars, when empty, are not subject to EPA regulation and can be disposed of in a normal manner. These guidelines are based on National regulations. State and local regulations and ordinances should be reviewed.
If you have any questions, please feel free to contact us promptly