Advantages of Covalence Shrink Sleeves (formerly Raychem)
Demanding ApplicationsIn order to protect metal pipe structures in contact with an electrolyte (soil, water) coatings need to have a high electrical resistance and low permeability to hydrogen and oxygen.
The coating must also be physically strong and chemically stable.
Additionally, the requirements of particular applications, like high operating temperatures necessitate specific tailoring of all pipeline coatings, including heat shrinkable sleeves.
Optimal SolutionsTo provide the optimal solution for each application, Raychem offers a range of products based on an irradiated crosslinked polyethylene carrier, combined with a hot melt or mastic coating applied in the factory to that heat shrink backing.
The main purpose of the crosslinked carrier (the actual heat shrink sleeve), called the backing, is to provide a strong barrier against electrical current, permeation and mechanical forces.
The adhesive assures long term bonding of the backing to the pipe and provides added electrical resistance (which is a good thing in spite of the propaganda you are regularly exposed to) and mechanical strength.
Thickness of the backing and adhesive depend on the application requirements.
To sum that up: Strengths of the heat shrink sleeve include (but are not limited to):
- Chemical Resistance of heat shrink backing and the selected adhesive
- Flow and fill of the hot melt adhesive or mastic sealant
- Mechanical Strength of the heat shrinkable backing (which can potentially be multiple layers and include fiber reinforcement)
- Electrical Resistance of both the backing and the adhesive. A coating with no electrical resistance means your pipeline is going to rely on your CP system almost solely for corrosion prevention. Why not just leave the field joints as bare steel if that is your goal?
Three Layer CoatingsFor the increasingly common (in Europe, South America and Asia) three layer factory applied pipeline coatings, Raychem / Covalence has developed a three layer field applied field joint coating. To provide a homogeneously coated pipe surface in the girth weld area, a layer of two component epoxy is first applied to the surface of the pipe. A specially designed shrink sleeve is then applied over the wet epoxy.
The three layer heat shrinkable coating system performs extremely well in resisting cathodic disbondment. It also offers high shear resistance against soil load and consequently ensures long service life.
High Reliability, High PerformanceRaychem (now called Covalence) has more than 40 years of experience in the development and manufacturer of heat shrinkable products. Continuous improvement ensures state of the art performance. Approval by testing agencies around the world guarantees suitability for individual applications and field conditions.
- Two layer and three layer constructions complement wide range of pipe coatings
- Top quality hotmelt, copolymer coated sleeves resist elevated pipe operating temperatures and soil stresses on all pipe diameters.
- Mastic coated shrink sleeves balance performance, economy and easy of installation.
- Three layer sleeves with epoxy primer and hotmelt copolymer have excellent resistance to both cathodic disbondment and hot water immersion, even at maximum rated operating temperatures.
- Fiberglass reinforced heat shrink sleeves withstand the high stresses of directional drilling
- Self-healing adhesive slow automatically repairs minor mechanical damage
Low Installation Costs- No primer required for two layer heat shrink sleeve systemes - install directly on cleaned and preheated pipe surface
- No waiting for primers to cure. The shrink sleeve is installed directly over the wet epoxy
- Simple tools such as a hand brush, power brush or blast cleaning and propane torches are used for installation of the heat shrink sleeve
- All products available as Uni sleeve construction. Uni sleeve means the closure strips are attached to the shrink sleeve here in our shop allowing for quicker installation in the field and dramatically fewer field issues.
- Easy to understand installation instructions are shipped with every product; in every box of shrink sleeves. Clear product labelling on the outside of the boxes allows rapid on site installation.
Post a Comment