GB1200030A - Explosion-proof electrical connector - Google Patents

Abstract

1,200,030. Two-part couplings. FOXBORO CO. 20 May, 1968 [24 May, 1967], No. 24031/68. Heading H2E. When connectors 10, 30 (Fig. III) are mated or separated in an explosive atmosphere, arcing between the contacts is prevented from causing a secondary, external explosion by mounting female contacts 15, 16, 17 in chambers 12, 13, 14 having lead-in passages 26, 27, 28 for male contacts 18, 19, 20, such that the ratio of the volume between each female contact and its chamber to the internal surface area thereof is in the order of 1/100 (thus any explosion occurs in a limited volume and is of limited force), and such that the space between each pair of mating contacts and their respective passages and chambers is sufficiently small compared with the internal surface area thereof to quench the flames of the explosion. This obviates the need for long passages and a critically tight contact-passage fit. The connector 10 comprises a glass-filled diallyl phthalate housing 11 having an opening, for a cable 21, sealed by two strips of thermosetting phenolic resin (23, 24, Fig. I, not shown), and thermoplastic blocks (22, 25). The housing 11 is received in a spring clip 31 (Fig. IV) having tabs 41 and indents 38 respectively locating shoulders 42 and guides 37 of a cover 32; cable clamps 33, 34 being provided. The clip 31 has slots 44 for engaging the edges of an aperture in a mounting panel (29, Fig. VIII, not shown). The male connector 30 is fixed to the panel by a bracket (Fig. VIII). Contacts.-The earth pin 18 is circular and longer than rectangular pins 19, 20.