GE XMTC

XMTC User’s Manual 59
Appendix B. Typical Applications
Appendix B. Typical Applications
B.1 H
2
in N
2
in Heat Treat Furnace Atmospheres
The XMTC can be used to measure the concentration of hydrogen (H
2
) in nitrogen (N
2
) in a heat treat furnace
atmosphere.
B.1.1 Problem
Mixtures of H
2
and N
2
are used as controlled atmospheres in the heat treating of metals. These mixtures are
well-defined and need to be maintained in order to assure product quality and consistency. Dissociated ammonia is one
such atmosphere. Here, ammonia is broken down into free N
2
and H
2
in a 25 to 75% mixture.
B.1.2 Equipment
A typical instrumentation package includes a 2-port (Sealed Reference Gas - air) XMTC transmitter with a 4-20 mA
range of 0-25% H
2
mounted in a sample system similar to the one shown in Figure 56 below. A display package is
often specified.
Figure 56: Sample System
INPUT
OUTLET
SAMPLE
OUTPUT
INLET
SPAN GAS
INLET
ZERO GAS
INLET
SAMPLE
N2
N1
N3
N4