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MAN0530 Issue 09 October 03 Searchline Excel
2104M0506
4. CROSS-DUCT EXCEL
4.1 INTRODUCTION
The Cross-Duct version of Searchline Excel gas detector is designed for applications where
the path to be monitored is between 0.5 and 5 metres. It operates on the same principle as the
Open-Path Excel, but instead of having the Transmitter and Receiver at opposite ends of the
path, they are both located on the same mounting plate.
NOTE: THE INFRARED BEAM IS INVISIBLE AND EYE SAFE.
A retro-reflector at the opposite side of the duct directs the beam from the Transmitter back
towards the Receiver. Most of the details for operation of the Open-Path Excel apply to the
Cross-Duct version. The following sections highlight the differences.
4.2 GAS DETECTOR DESCRIPTION
Transmitter
Mounting plate
Mounting cell
Conduit
Junction box
(type DVC100 shown)
Receiver
Double-glazed
retro-reflector
Path
0.5m - 5m
The Cross-Duct Searchline Excel gas detector consists of a Transmitter and Receiver, which
are fixed to a mounting block, and a separate retro-reflector. The Transmitter and Receiver are
mounted on a cast metal block (mounting cell) that houses a beamsplitter, and incorporates a
gassing cell for functional testing purposes.
The Receiver is the same as the standard Open-Path version, but the Transmitter uses a
different design, which gives a uniform intensity across the beam at the shorter path lengths.
There are two variants of the Cross-Duct Excel, which differ in the ranges over which they
operate. These are:
Short Range 0.5 — 2.5m ( 20in — 8ft )
Long Range 2.5 — 5m ( 8ft — 15ft )
The long range gas detector uses a large retro-reflector, which is twice the size of the short
range retro-reflector.
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