Installation | Model 9060L | |
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Note: Mount the probe as close to the combustion source as possible. This reduces the lag time inherent in the sampling process and results in better control.
The probe has a typical response time of less than four seconds, so most of the delay time is associated with the transit time of the gas from the point of combustion to the point of sensing.
Probes can be mounted at any angle. When feasible, a vertical installation with the probe facing vertically downwards will eliminate the need for a filter. This is especially useful for processes with particulates in the flue gas. If a vertical mounting is not possible under these conditions, a filter may be necessary. This may require periodic filter replacement depending on the severity of the process.
If a flow guide tube is used (heated probes only), it is important that the fin points directly downstream. If the exact flow direction is not known, use a wind vane that can be made from a piece of wire and flat metal. If the flow guide tube is installed facing the wrong direction for any period, the suction filter may block with flue gas dust particles.
The maximum temperature for an unsupported flow guide tube is 750°C (1380°F). Above this temperature, provide a support and flanged flexible rubber joint as shown in Figure
When installing a probe into a hot environment, slide the probe in slowly to avoid thermal shock to the internal ceramic parts. If the flue gas is 1000°C (1830°F), it should take approximately ten minutes to install a 500 mm (20”) probe, moving it in steps of about 20 mm (1”).
CAUTION: IT IS IMPORTANT THAT THERE ARE NO AIR LEAKS UPSTREAM OF THE OXYGEN SENSING POINT, OTHERWISE THERE WILL BE A HIGH OXYGEN READING.
If the probe is to be installed on a bend in the flue, it is best to locate it on the outer circumference of the bend to avoid dead pockets of flue gas flow. While the standard 9060L probe with a ‘U’ length of 250
mm(10”) will suit most low temperature flue applications, it is occasionally necessary to have a longer probe with the sensing tip in the center of the flue gas stream.
Although it is rare, occasionally a probe may sense oxygen vastly different from the average reading in the flue gas. If it occurs, move the
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