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US 4,497,664 AGranted
Erosion of a solid surface with a cavitating liquid jet
AssigneeAlsthom-Atlantique
InventorPhilippe Verry
Life of this patent
Estimating the term…
Abstract
A solid surface is eroded by directing a liquid axially through a converging passage in a nozzle toward the surface, then deflecting the liquid in a lateral direction parallel to the surface while the liquid is subject to cavitation.
Claims10
In a device for the erosion of a solid surface by a cavitating flow, said device comprising:
- a source (2) of a working liquid at high pressure, said liquid being vaporizable at the ambient temperature at a pressure lower than the ambient pressure,
- at least one nozzle (B) supplied by said source with liquid, and forming a converging tube (T) in its "longitudinal" direction, so as to form said liquid into a high speed jet while reducing the pressure of the liquid, and to direct said jet to the surface (S) to be eroded along said longitudinal direction,
- and means for effecting cavitation connected to said nozzle to lower the pressure of the liquid locally, to vaporize it partially, and to create violent displacements of the liquid on recondensation of the vapor downstream in a condensation area (ZC) where the pressure is increased and which is in contact with the surface to be eroded,
- the improvement wherein the means for effecting cavitation include a deflector (D), fitted to said nozzle by means (D3) positioning it in the neighbourhood of the surface (S) to be eroded, said deflector being oriented so that it receives the jet on its exit from the nozzle (B) and deflects it in a "lateral" direction to form a flow parallel to said surface, said device including means (G1) for maintaining said nozzle at a predetermined distance from said surface, and said deflector having a downstream edge forming an "active" ridge (D2) for causing separation of the flow and for formation of a pocket of vapor (PV) immediately downstream of said ridge between the separated flow and the surface to be eroded.
1 more element
In a process of erosion of a solid surface by a cavitating flow, said process comprising the steps of:
- directing a flow of a working liquid under high pressure, said liquid being vaporizable at the ambient temperature at a pressure below the ambient pressure, through a nozzle (B) forming a converging tube (T) in its "longitudinal" direction to form a high speed jet with said liquid, while reducing the pressure of the liquid, and directing said jet toward the surface (S) to be eroded along said longitudinal direction, and
- creating cavitation in said liquid jet by lowering the pressure locally to partially vaporize the liquid and create violent displacements of the liquid upon recondensation of the vapor in a condensation zone (ZC) where the pressure is raised and which is in contact with the solid surface to be eroded, the improvement wherein said step of creating cavitation comprises urging said jet against a deflector (D) positioned close to the surface (S) to be eroded, such that the deflector receives the jet on its exit from the nozzle (B) and deflects it in a "lateral" direction parallel to said surface with the edge of said deflector forming an "active" ridge (D2) causing a separation of the flow and the formation of a pocket of vapor (PV) immediately downstream of said ridge between the separated flow and the surface to be eroded.
Dependencies are inferred from the claim text.