Nozzle for axial siphon powder delivering type cold spray

Abstract

The invention belongs to the technical field of cold spraying, and relates to a nozzle for axial siphon powder delivering type cold spray, wherein a rear end part of a cylindrical nozzle body is fixed with a butt-jointed screw cap, a working gas inlet is arranged on a top side face of the rear end part, a conical cylinder shaped front nozzle air chamber is arranged in an inner cavity of the rear end, and a powder delivering pipe is fixed on a central axis of the inner cavity in a serial connection manner; the rear end opening of the powder delivering pipe is abutted with a scaling pipe, and the rear end of the scaling pipe is extended out of the screw cap; a joint between the powder delivering pipe and the scaling pipe is provided with an extension pipe interface in an outer sheathing manner; the front end opening is fixedly connected with a long cylindrical nozzle extending pipe in an outer sheathing manner through a fixing screw hole of an extension pipe, the rear end part of the nozzle extending pipe is in communication with the extension pipe interface, and a nozzle throat part is arranged at the center of the inner cavity of the nozzle body; the length of the nozzle extending pipe can be adjusted according to the pressure of the working environment and the sprayed raw material. The nozzle is simple in structure, reliable in principle, mature in preparing technology, stable in siphon air flow, uniform in powder delivery, low in production cost, high in efficiency, friendly in environment and good in application prospect.

Description

Technical field: [0001] The invention belongs to the technical field of cold spraying of surface treatment engineering, and relates to a new structural design of a supersonic nozzle for high-pressure and low-pressure dual-purpose cold spraying, in particular to a nozzle for axial siphon powder-feeding cold spraying. Background technique: [0002] As a new surface treatment engineering technology, cold spraying is an improvement and development of traditional thermal spraying technology. The principle of cold spraying process technology is to use high-speed impact to break particles and metal on the bottom surface under low temperature and solid state. The atomic structure is combined, and it is deposited on the surface of the substrate through large plastic deformation to form a dense and firmly bonded coating, which has many advantages that traditional thermal spraying cannot match. The specific working principle of the currently used cold spraying equipment is as follows: ...

AI Technical Summary

Problems solved by technology

However, the nozzles involved in these existing technologies generally have common shortcomings such as low spraying efficiency and rapid wear of the nozzle wall surface. The hollow type can be used to improve the powder feeding characteristics, which can avoid the loss of the wall surface. However, due to the characteristics of the air flow, the central flow rate is relatively low. Low, which is not conducive to the overall powder acceleration; and the powder feeding flow control range of the existing nozzle structure is limited. To achieve the required powder feeding volume, the area of ​​the throat is too large, and the requirements for the air compressor or gas pipeline are too high. In many cases, it is difficult to apply this condition during construction

In addition, due to the large difference in expansion ratio and gas flow requirements of high-pressure and low-pressure cold spraying, usually existing nozzles can only use a single nozzle structure and its low-pressure or high-pressure spraying method; The corresponding spray gun and the applicable nozzle structure must be replaced, which is very unfavorable to the flexibility of processing, resulting in low production efficiency and unsatisfactory economic value

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