6 • 65-2443SS-XX PPM Hydrogen Transmitter
Description
This section describes the ppm hydrogen transmitter’s components. It is a 4 to 20 mA type detector
head. It consists of the ppm hydrogen detector, amplifier, and junction box.
Figure 1: Component Location
PPM Hydrogen Detector
The ppm hydrogen detector is a MOS type (metal oxide semiconductor) detector packaged in a 1/2
NPT nipple with a sintered metal flame arrestor on one end allowing ambient air to diffuse into the
detector. The flame arrestor also contains any sparks which may occur within the detector. The 1/2
NPT mounting threads at the top of the detector allow you to mount it into the bottom conduit hub of
the junction box. A rainshield screws onto the bottom of the detector (flame arrestor end). The
rainshield helps protect the detector from rain and debris in the monitoring environment. Three color-
coded leads extend from the top of the detector. The leads allow you to connect the detector to the
amplifier.
The detector has a built in molecular sieve that only allows hydrogen to diffuse into the detector. The
output of the detector is non-linear and is linearized by the amplifier (see below).
J-Box
W
S PAN
DE
T
E
C
T
O
R
R
B
PW
R
/
SI
G
S
Reducing Bushing,
3/4 NPT to 1/2 NPT
Amplifier
Hydrogen Detector
Locking Set Screw
LI
N
E
A
R
