The IP.com Prior Art Database
English (United States)
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HVOF Coatings For Outside Wear Protection (e.g. Rotors), For Inner Wear Protection e.g. Stators
Positive displacement mud motors consists out of a rotor and a stator. Both parts have a specific designed contour to be able to use the pressure in the drill fluid for creating a rotating movement for driving the drill bit. The rotor outside as also the stator inner diameter have to be protected against corrosion of aggressive fluids, wear because of particles in the fluid to increase mud weight and reduce friction. The common method is to use a combination of chrome and rubber which has a low coefficient of friction. To protect against corrosion metal parts become Ni coated before Cr coated or are made out of stainless steel. Since Cr cannot be used in e.g. high chloride containing environments and other chemical aggressive fluids, the invention will combine the advantages of Cr coating with extended chmical resistance. This invention covers wear and corrosion protection by coating of the parts e.g. rotor outside or stator inside with a adequate powder in process method HVOF, which is a high velocity oxigen flame coating.
A fine powder is shot with high velocity onto the part. For outside coating that can be done with a specific spray torch, for inner coating a small torch has to be move on a lance inside the tube or stator. The heat to m...