Analysis of layouts of equipment for d-gun and other methods of thermal spraying

Abstract

From explosive processing methods, attention is growing towards the use of a safer and more convenient source of energy in the form of gaseous detonation. The level of pressures, temperatures and velocities that develop behind detonation or close to them in intensity shock waves in gases, as well as the impulsive nature of the impact of these factors, determine the great potential for their technical and technological application. The most detailed and widely used field of practical use of gaseous detonation is the D-Gun spraying of powder protective and functional coatings. The increased requirements for this technology and, especially, the need to use specially equipped production facilities hinder the widespread introduction of D-Gun spraying methods. In order to minimize the impact of hazardous and harmful production factors on workers, a generally accepted approach is a number of mandatory requirements: placement of D-Gun installations in hermetic, soundproof boxes; the use of local suction in the process zone of spraying and general exchange of supply and exhaust ventilation of the working box as a whole; compliance with the requirements for the safety of the supply of combustible gases, etc. The article is devoted to the analysis of the main layouts of equipment for thermal spraying of coatings on the example of detonation-gas installations. Detonation-gas installations (D-guns) contain the following main units: barrel (combustion chamber); ignition chamber, gas distribution mechanism; powder feeder; igniter of a combustible mixture of gases; system of localization of combustion in the barrel; cooling system; a control unit that provides the necessary sequence and duration of operation of the D-gun actuators at each operating cycle, as well as the duration of the operation of the D-gun as a whole, the inclusion and deviation of individual elements according to control commands or signals from the control system; gas control unit; control system, including sensors of the main parameters of the spraying process; remote control. The main layout schemes are: full placement of all components and systems of equipment in production shops (premises); placement of the sprayer in semi-closed chambers for performing manual or mechanized operations of thermal spraying; complete placement of equipment in isolated rooms with remote control; complete placement of equipment and operators in sealed chambers with a controlled environment; spraying chambers installed in production lines to isolate D-Gun workplaces; compact chambers for complete isolation of the part (or partial - spraying zone; hermetic compact chambers for complete isolation of the part with the introduction of the output nozzle of the spraying device into it.