Oil in Water | Part III | |
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3.This ultra filtered water sample is calledzero fluid for the process stream.
a.Gravity feed introduce through the calibration reservoir into the sample cell this Zero fluid colected above. Record the heights of the reference and measuring peaks after identification of the peaks.
b.Prepare a Span fluid using the same Aero fluids. See Part III, Section 5.6.2.
Gravity feed the Span fluid into the calibration reservoir and Sample Cell. Record meter reading. Record the measuring and reference peak heights observed on the oscillioscope.
Interpretation of Observations
The upscale reading of the meter in Step b shows the relative signal level of the oil equivalent signal. The oscilloscope may show a gross imbal- ance of the peaks as compared to the Zero water peaks.
NOTE: The cell can be charged with zero water (filtered) (or Span) spaged sample) by pouring the fluid into the calibration reser- voir.
5.5.6Balancing the Optics for Equal Light Trans mission with Zero Fluid in the Sample Cell
The objective of this procedure is to obtain measuring and reference peak heights as displayed on the oscilloscope which are approximately equal, with the tallest of the peaks set at 7 to 8 volts. This must be done with filtered sample water (zero water) in the cell which contains background components.
The procedure is purely mechanical and consists of adjusting the amount of light passing through either the measuring or reference filter, never both. Screens (wire mesh) of varying density are used for this opera- tion and are part of the small tool kit accompanying the instrument.
1.Observe the oscilloscope and judge if optical balancing is needed. When the difference is less than 2 volts, balancing is not required. The tallest of the two peaks should be adjusted to 7 or 8 volts with the gain control R1 on the detector PC Board. When this cannot be done because both peaks are too short or too long, search for screens mounted in the light path, usually located in a holder on the light pipe which interconnects the detector and sample module, and remove or add screens, as necessary.
Teledyne Analytical Instruments | Part III: |
