General design specification for insensitive electric-initiators
1 Introduction
This standard specifies the general design requirements, design qualification tests and qualification methods of insensitive electric-initiators, with a view to determining the electrical performance and mechanical structure robustness of the insensitive electric-initiators as well as their output and resistance to hazardous service environments.
1.1 Applicability
1.1.1 This standard is applicable to the design type approval of insensitive electric-initiators.
1.1.2 The insensitive electric-initiators to which this standard applies are divided into the following two categories:
a. Category A: Electric-initiators that can be activated within one second (excluding delay time of delay elements) with a power supply of 28±2 V with a capacity of not less than 10 A.
b. Category B: Electric-initiators that cannot be activated within one second (excluding delay time of delay elements) with a power supply of 28±2 V with a capacity of not less than 10 A.
2 Terms
2.1 insensitive electric-initiators
independent ignition or detonation elements with a non-firing sensitivity of at least 1A1W excited by electric energy
2.2 bridge
resistance element, through which the electric energy is converted into heat energy (it is also converted into light and shock wave for the exploding bridge), so as to directly excite explosives and medicament
2.3 firing leg wire
integral part of a bridge, which is usually a metal wire or metal bar, and used is to connect the bridge with the firing power supply
2.4 bridge circuit
turn-off circuit consisting of a bridge, firing leg wire, and other electrical elements permanently connected in series or parallel with the bridge, which does not include electrical elements externally connected to the firing leg wire
2.5 minimum total firing energy of 50 ms
minimum firing energy that at least 99% (with the confidence level of 95%) of the electric-initiators are excited within 50 ms. For electric-initiators equipped with delay elements, the time for applying firing energy is 50 ms, but the action time of electric-initiators shall be extended to include the specified maximum delay time of the delay elements
2.6 maximum non-firing energy
maximum firing energy that more than 1% (with the confidence level of 95%) of the electric-initiators cannot be excited within five minutes. For electric-initiators equipped with delay elements, the time for applying firing energy is five minutes, but the action time of the initiators shall be extended to include the specified maximum delay time specified of the delay elements.
3 Requirements
3.1 Design requirements
3.1.1 General requirements
The electric-initiators shall be simple in structure, small in size, light in weight and universal.
3.1.2 Materials
3.1.2.1 Inert materials and explosive materials shall be selected as specified in national standards, national military standards, professional standards (ministry standards) or company standards.
3.1.2.2 The selection of inert materials shall meet the environmental, strength and weight requirements of the intended unit of use specified in this specification. Without the approval of relevant competent authority, mildew-prone materials are prohibited.
3.1.2.3 Carbon shall not be used as the bridge material without the approval of relevant competent authority.
3.1.3 Firing leg wire
All firing leg wires of electric-initiators shall be provided with measures of mutual short circuiting, and shall be kept short-circuited all the time except for bridge circuit resistance measurement and functional test. If the electric-initiator has more than two pieces of firing leg wires, identification marks shall be provided.
3.1.4 Sealing
The electric-initiators shall be sealed, and the sealed electric-initiators shall meet the leakage requirements in 3.1.9, the environmental requirements in 3.3 and the functional requirements in 3.4.
3.1.5 Insulation between bridge circuit and crust
