Model 5100E
–
Introduction and Overview
1.3.6
Sensor
The Neutronics Inc
ZR-500E mini Zirconia
sensor for measuring percent range oxygen is a cost effective
solution for many applications. It is a solid-state device based on a Zirconia solid electrolyte sensor with a
low power, on-board heater, and two electrodes. Unlike many solid-state oxygen sensors, the ZR-500E
does not require a reference gas for normal operation (see calibration requirements).
The sensor is mounted directly onto a printed circuit board that supplies bias and heater voltages to the
sensor element. A small capillary on the sensor surface controls diffusion of oxygen into the sensor. At
operational temperature, oxygen is electrochemically reduced, causing current flow through the solid
electrolyte. Oxygen concentration in the sample gas is determined by measuring the current flowing
through the sensor’s two electrodes.
H
H
S +
S-
A
Ammeter
(Oxygen Analyzer)
Sensor Bias
Voltage
Heater Power
The robust design of the ZR-500E sensor assures accurate measurement as well as a quick response
characteristic to serve a wide range of oxygen measurement applications. Its expected operating life is 2
years under normal operating conditions, and it has an unlimited shelf life. It is not affected by position,
and it may be exposed to high atmospheric pressures with no ill effect on performance.
1.3.7
Sensor Flow-Through Head
The sensor mounting-base allows the Model ZR-500E sensor to be used for process monitoring. It serves as
both the receptacle for the sensor and the delivery system for a gas sample from a process vessel or
stream. It includes a sample inlet, a flow-through chamber a sample exhaust, and a screw-in receptacle for
the oxygen sensor.
1.3.7.1
Sample Gas Inlet
A sample gas inlet port is provided for installation with a process oxygen sampling system. Gas must be
directed from the measured process to the sample inlet port via positive pressure from the source, or an
external pump. The Model ZR-500E sensor and flow-through head combination can be installed in any
Neutronics Inc. Process Sampling System.
1.3.7.2
Sample Gas Exhaust
A sample gas exhaust port is provided for installation with a process oxygen sampling system. Gas must be
directed from the sample exhaust port to an exhaust at ambient pressure. Any change in pressure to the
exhaust port of the analyzer will affect its reading and accuracy.
Figure 3
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ZR-500E sensor circuit
