Explosion-proof electrical apparatus and method of assembly

An explosion-proof electrical apparatus comprising:

• first and second adjacently disposed enclosures;
• electrical devices mounted in respective ones of said enclosures, each enclosure having an internal screw-threaded hole, said holes being aligned with one another;
• sleeve means having external first and second screw threads disposed at first and second ends thereof and adapted to be secured in respective ones of said holes, said sleeve means including a first longitudinal through-passage having first and second ends corresponding to said first and second ends, respectively, of said sleeve means, said first end of said first through-passage having an internal third screw thread;
• a feedthrough bushing mounted in said first through-passage and having an external fourth screw thread secured in said third screw thread, said feedthrough bushing including a second longitudinal through-passage having first and second ends, said first end of said second through-passage being disposed adjacent said first end of said first through-passage and having an internal fifth screw thread;
• a feedthrough seal member mounted in said second through-passage and including a third longitudinal through-passage, said third through-passage having first and second ends, said first end of said third through-passage being disposed adjacent said first end of said second through-passage and having an external sixth screw thread secured in said fifth screw thread;
• and
• a plurality of electrical conductors extending through said third through-passage and embedded within sealing compound occupying said third through-passage.

An explosion-proof fitting assembly for electrically interconnecting electrical components mounted in first and second adjacently disposed enclosures, respectively, said fitting assembly comprising:

• a feedthrough bushing having an external screw thread adapted to secure the feedthrough bushing with respect to the enclosures, said feedthrough bushing including a longitudinal through-passage having an internal screw thread;
• a feedthrough seal member having an external screw thread secured in said internal screw thread, permitting said feedthrough bushing to move longitudinally along said feedthrough seal member, said feedthrough seal member including a longitudinal through-passage;
• a plurality of electrical conductors extending through said through-passage of said feedthrough seal member and being embedded within sealing compound occupying said through-passage of said feedthrough seal member;
• and
• a hollow sleeve structure in which said feedthrough bushing is mounted, said sleeve structure having an internal screw thread in which said external screw thread of said feedthrough bushing is secured, said sleeve structure including external screw threads at opposite ends thereof adapting said sleeve structure for threaded connection with respective enclosures.