Vitreous coating application by induction heating and integration with induction kinetic weld joining
Induction heating facilitated coating systems and processes for pipes overcome corrosion and erosion of the pipes at extreme temperatures and pressures in applications including oil and gas downhole tubulars and pipelines as well as processing facilities. Being based on vitreous fused inorganic compounds, the present invention achieves very high corrosion resistance at remarkably modest cost. Attractive economics and immunity to chlorides and moisture permeation at extreme concentrations and temperatures also make it well suited to desalination plants and potable water piping applications. Due to its extreme temperature resistance, it also is very well suited for geothermal wells. Additionally, due to its characteristic smooth durable surface, the present invention is ideally suited for applications involving the opposite of corrosion, namely scaling problems, such as fouling in sewage systems and scale buildup in heavy oil wells.
1. A method of applying a vitreous coating to a metal pipe by a dry process using induction heating and electrostatic sprayers, the method comprising:
advancing an induction heating apparatus along an interior surface of a metal pipe, wherein the induction heating apparatus comprises at least one ring-shaped induction coil, a first baffle and second baffle, wherein the first baffle and second baffle at least partially and circumferentially seal off a portion of the interior surface of the metal pipe in proximity to the at least one ring-shaped induction coil, wherein an enclosed processing area is proximate to the at least one ring-shaped induction coil, wherein the enclosed processing area includes at least one electrostatic sprayer;
energizing the at least one ring-shaped induction coil to controllably heat the interior surface of the metal pipe in proximity to the enclosed processing area;
energizing the least one electrostatic sprayer and electrostatically spraying a dry frit onto the interior surface of the metal pipe; and
forming a vitreous coating on the interior surface of the metal pipe from the dry frit by fusing the dry frit onto the interior surface of the metal pipe as the induction heating apparatus advances along the interior surface of the metal pipe.
2. The method of claim 1 , wherein at least one of the first baffle and the second baffle are porous to gases.
3. The method of claim 1 , wherein at least one of the first baffle and the second baffle is associated with a fabric seal circumferentially contacting the interior surface of the pipe.
4. The method of claim 1 , further comprising:
quenching the metal pipe with a ring-shaped quench head, wherein the quench head cooperatively advances along the exterior of the metal pipe as the induction heating apparatus advances along the interior surface of the metal pipe.