Abstract:
A high temperature flame spray or plasma effects thermal spray impact of molten materials against a target area of a surface to be built up, which molten particles, when cooled, are in tension, and an impact fusion internal burner device producing a supersonic jet stream impacts thermal spray heated solid particles against the surface in the target area such that the high velocity of the individual solid particles are impact fused, causing compressive stresses to be set up in the fused solid particles. The individual particle tensile and compressive stresses cancel one another to form an overall essentially stress-free coating. The flame spray molten particles and the flame spray heated solid particles may impact the surface concurrently at a same impact point. Alternatively, thin separate layers of the molten particles and the heated solid particles are deposited on the surface to be built up and superimposed on each other such that the tensile and compressive stresses of the particles of respective superimposed layers cancel each other out.
Abstract:
An internal burner for producing a subsonic air-fuel flame jet capable of flame finishing granite of similar hard stone has a body forming a closed combustion chamber fed with an essentially stoichiometric flow of compressed air and fuel such that upon ignition and combustion of the reactants, there is produced at pressures in excess of 30 psig hot products of combustion. A first nozzle within the body of relatively small diameter d.sub.1 at the exit end of the combustion chamber expands the products to supersonic velocity. A duct of sufficiently large diameter within the body downstream of the first nozzle and open thereto converts a jet of hot gases to subsonic velocity by shock action prior to discharging the hot gas products of combustion. A second nozzle having a large diameter d.sub.2 in excess of the diameter d.sub.1 of the first nozzle and open to the duct at the end opposite the first nozzle produces a subsonic flame jet to be directed against the rock surface.
Abstract:
A high voltage, high current is applied between a cathode electrode and a conductive body forming a spray nozzle and acting as a second anode electrode aligned with the first electrode and being spaced therefrom. A vortex flow of plasma-producing gas is established within a cylindrical body carrying said electrode to create a low pressure core of gas flow extending through the anode passage to establish an extended ionized arc column throughout the anode passage with the rate of gas flow adjusted and the arc current correlated to the anode nozzle passage diameter to produce a supersonic extended ionized arc column which extends beyond the end of the nozzle by a distance which is approximately four times the nozzle passage diameter. Preferably the material to be sprayed is introduced into the extended ionized arc column beyond the end of the nozzle to maximize the spray rate without undesirably overheating the spray material.
Abstract:
A system for deriving useful energy from a windmill in which a liquid pump is driven by the windmill. Useful energy is obtained by either a fluid driven generator or a friction heater. The output of the pump and the speed of the windmill are controlled by a constant volume valve in the fluid circuit.
Abstract:
A supersonic flame jet device includes a body having an entry portion of relatively small cross-sectional area, an expanding supersonic nozzle section and a cylindrical duct of extended length connected in series with each other. In using the device, an oxidant at high pressure is introduced into the entry passage wherein the flow is increased to sonic velocity. The sonic velocity flow of oxidant is then introduced into the passage of expanding cross-section in the direction of the gas flow while introducing a fuel to be burned into the flow of the oxidant. The velocity of flow of the oxidant or the oxidant and the fuel is then increased to supersonic velocity prior to entry into the extended duct of constant cross-sectional area where a shock is produced to stabilize flame reactions along the extended duct length whereby a supersonic flame jet will exit the extended duct.
Abstract:
A fuel and oxygen mixture is combusted within an internal burner combustion chamber at temperatures ranging from 250 psi to 1,000 psi. The products of combustion are directed through a restricting nozzle throat and a supersonic expansion nozzle section into an elongated duct formed by an extended nozzle length. Abrasive particles are introduced into the supersonic flow jet stream near the entrance to the elongated duct to accelerate the particles to extreme velocity, with the combustion pressure maintained sufficiently high to limit the jet stream temperature to that which is insufficient throughout the elongated duct to raise the particle temperatures to the plastic point of the particle material. The temperature of the supersonic gas flow through the elongated duct may be reduced by the introduction of a cooling flow into the jet stream beyond the flow-restricting nozzle throat. The cooling flow may be a flow of water or other liquid coolant or cool compressed air.
Abstract:
A method of operation of a plasma torch, an internal burner or the like to produce a hot gas jet stream directed toward a workpiece to be coated by operating the plasma torch or internal burner at high pressure while feeding a powdered material to the stream to be heated by the stream and projected at high velocity onto a workpiece surface. The improvement resides in expansion of the hot gas prior to feeding of the particles into the jet stream thereby limiting the heating of the powdered material by the jet stream to that only sufficient to raise the temperature of the particles of the powdered material to a temperature lower than the melting point of the material, and maintaining the in-transit temperature of the particles to the workpiece below that melting point, while providing a sufficient velocity to the particles striking the workpiece to achieve an impact energy transformation into heat to raise the temperature of the particles to fusion temperature capable of fusing the material onto the workpiece surface as a dense coating.
Abstract:
A compressed air with or without water droplets in mist form and additional pure oxygen is passed over the radially exterior hot surfaces of an expansion nozzle having a L/D ratio of at least 3-to-1 and preferably surrounded by thermal insulation to enhance regenerative heat exchange between the expansion nozzle and the compressed air stream, as well as regenerative heat exchange with the exterior of a combustion chamber wall of an internal burner, also surrounded by thermal insulation prior to the compressed air entering the combustion chamber for ignition with a mixture of fuel. This permits large operating economics to be realized, reducing the need for expensive pure oxygen as the oxidant and permits the elimination of forced cooling by confined water flow for such internal burners.
Abstract:
In a combustion of plasma flame spray apparatus a tightly-packed array of individual wires or rods is fed into and through the plasma flame to heat, atomize and project against a surface to build up a coating thereon. The individual wires may be arranged as parallel strands or twisted together to form a cable. The wires are of circular diameters, and the twisted array of wires may be held together by a cement which is consumed when passing through the flame region. The cement may constitute a pyrophoric mixture such as a sheath surrounding the array of wires and consist of a stoichiometric mixture of two reactive metals including nickel and aluminum which react to form a nickel-aluminide.
Abstract:
A method and apparatus for reliable flame spraying utilizes a transferred arc from a plasma torch as created between the cathode electrode coaxial with the plasma torch nozzle and the end of at least one wire or rod fed into the transferred arc axially beyond the exit of said plasma torch nozzle. A high velocity annular gaseous sheath is formed concentrically about the extended arc column to form an arc column guide to restrict the arc column to within a region closely spaced radially from the axial extension of the nozzle. A thin walled tube close to but radially outside of the arc column is affixed to but may be electrically insulated from the plasma torch body forming the torch nozzle. Gas flow is effected along at least the outer surface of the tube in the direction of the extended arc column such that the arc column cannot penetrate the sheath high velocity gas to cause the arc to extinguish itself when the wire or rod is withdrawn from the arc column region. Inner and outer flows may be used, of differing gas types. A secondary arc may be set up between the ends of two wires or rods being fed into the arc region and operated in parallel with primary transferred arc.