61-1020/61-0230 Molecular Property Spectrometer
Description
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Description
The 61-1020 is a Molecular Property Spectrometer (MPS
TM
) type of detector which has some
advantages over a catalytic or IR type of combustible detector. The explosion-proof MPS detector
is immune to poisons, can be used in high humidity, can detect multiple gases simultaneously (see
Table 1), and does not require calibration as often as catalytic combustible sensors.
This section describes the components of the 61-1020: the MPS LEL detector and the junction
box.
Figure 1: Component Location
MPS Detector
The MPS LEL detector is made up of the MPS combustible gas LEL detector housed and
encapsulated in a pipe nipple. The pipe nipple has 3/4 NPT threads on each end and a 1-1/4 inch
hex that allows removal or installation of the detector with a wrench. A porous flame arrestor
coated with a hydrophobic film that repels liquids is on one end of the detector and allows sample
gas to enter the detector. Four color coded leads, red, white, green, and black, extend from the
other end of the detector. Use the leads when connecting the detector to the terminal block in the
junction box.
Junction Box
The junction box allows installation of the detector at a mounting site that is remote from the
controller while protecting the detector wiring connections. Two 3/4 NPT conduit hubs allow you
to mount the detector to the junction box and connect the wiring from the detector to a controller.
The terminal block within the junction box facilitates the wiring to the detector. A cover on the
front of the junction box allows access to the interior of the junction box. Three spacers installed
on the back of the junction box control the distance of the junction box from a mounting surface
and insure that there is enough room to install a calibration cup on the detector during calibration.
J-Box
Green
Red
White
Rubber
Spacers,
3X
MPS LEL Detector
Black
