An instrument system includes an instrument assembly having at least one
fitting projecting therefrom. The instrument system further includes at
least a first housing member including at least one alignment member
located therein. The alignment member preferably includes at least one
sloped surface which slopes toward at least one seating adapted to seat
the at least one fitting of the instrument assembly. The instrument system
further includes a second housing member which forms an explosion-proof
enclosure with the first housing member to enclose the instrument
assembly. The second housing member preferably forms an explosion-proof
enclosure with the first housing member via cooperating threading. The
instrument assembly can, for example, include electrical components for a
combustible gas sensor.
