Some Aspects Of Mass Flow Control of Shots in Pneumatic Systems

Author:  V.S. Nadkarni, M.C. Sharma
Source:  Conf Proc: ICSP-5, (p. 34-39)
Doc ID:  1993059
Year of Publication:  1993
Mass flow control of shot is an important factor to attain required and consistant peening intensity. Irregular mass flow of shot in pneumatic systems may give rise to different residual stress pattern in the work pieces of smae material and shape, though peened to the same Almen intensity. Experimental investigations were carried out to corelate shot sixe, nozzle bore and shot feed opening to mixing chamber (orifice diameter), which could provide uniform shot flow at different pressure and air inlet valve opeining in manual operated pressure systems. Different designs of mixing chambers were compared. In tubelar mixing chambers, concentric tube type mixing chamber gave better performance. Similarly individual orifice plate system was found more convenient than adjustable opening type feed valve. Results showed that in pressure peening system for uniform flow of shots, orifice diameter must be about 0.7 times the nozzle throat diameter. While in syphonic and gravity feed systems this proportion can be still larger. Syphonic systems worked well with orifice diameter 1.25 time the nozzle diameter.

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