SYSTEM DESIGN INFORMATION
16
4.3
GENERAL CONSTRUCTION
Fig. 13 shows a general view of a complete detector with its mounting bracket.
The detector is of robust construction to allow its use in harsh environments.
The detector comprises a two-part stainless steel ‘spigot-type’ enclosure. Both halves of the
enclosure are guided into the correct position by an alignment pin. The front section of the
enclosure contains the detector optical and electronic sub-assemblies. Mating connectors at the
rear of the front section and on the terminal board mounted in the rear section of the enclosure
provide a means of electrical connection to the installation cables.
The rear enclosure of the FV311 series of detectors is provided with two M20 gland entry holes at
the bottom of the detector. Two 10-way terminal block arrangements are provided for termination
of installation cables.
The rear enclosure of the FV312 series of detectors is provided with a permanently attached cable
sealed in the enclosure. With these detectors, termination of installation cables is made in an
external EExe junction box.
Both types of rear enclosure have a dedicated earthing point on the side of the casting (Fig. 14) to
connect an earth bonding wire from the nearest safety earthing point to the enclosure. Also, a
tagging loop is provided on the side of the rear enclosure to attach a suitable label to identify the
detector on site.
124.2
92
181
122.4
94.4
THE BRACKET
MUST
BE MOUNTED
IN THIS ORIENTATION
Fig. 12
Adjustable Mounting Bracket and Surface Mounting Dimensions
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