Verma, H.K. (2013) Investigation of Delay Time Precision in Pyrotechnic Detonators. Journal of Rock Mechanics and Tunnelling Technology , 19 (1). pp. 19-29. ISSN 0971-9059

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Abstract

Despite advancement of initiating devices, use of electrical detonators with pyrotechnic composition is common in Indian mining and construction industry. The cost benefit achieved by electrical detonators over shock tube initiation system and electronic detonators is huge. Delay detonators made with pyrotechnic delay compositions have inherent scattering in their delay timings. It is desirable to use precise detonators to achieve better fragmentation, less vibration and noise. Overlapping of delay period is undesirable from production as well as safety point of view. In order to assess delay accuracy of electrical pyrotechnic detonators of a domestic manufacturer, randomly selected fifty units from each delay period (0 to 6) from the same batch of detonators that were found suitable for use in underground coal mines in respect of their incendivity, handling & electrical safety, performance and water resistance characteristics were evaluated. Overlapping possibilities amongst delay periods were evaluated by calculating Winzer index and graphical methods. The findings reveal that significant scattering exist in all the delay periods. Scattering increases with higher delay periods. Overlapping possibilities between delay period 5 and 6 is found to be significantly high. Winzer index for the pair of delay period 5 and 6 is found to be very close to the threshold value for overlapping.

Item Type:	Article
Uncontrolled Keywords:	Permitted delay detonator; Overlapping; Inflammable mixture; Delay time; Blasting off-the-solid; Pyrotechnic composition.
Subjects:	Blasting
Divisions:	UNSPECIFIED
Depositing User:	Mr. B. R. Panduranga
Date Deposited:	13 Jan 2020 06:01
Last Modified:	13 Jan 2020 06:01
URI:	http://cimfr.csircentral.net/id/eprint/2143

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