Teledyne 6600 - Manual (Page 96)

1-6 Part III
Part III Model 6600
Teledyne Analytical Instruments
Should Teledyne receive no representative sample of water or oil for
testing purposes, Teledyne will not be held responsible for the unsatisfactory
functioning of the analyzer due to sample related nonconformities. If the end
user is unable to provide samples, a spectral scan or a detailed description of the
type(s) of oil(s) present is prefferred. The user is responsible for proper
calibration of the unit, at commissioning stage, against the oil(s) found in the
sample fluid to be analyzed. TAI assumes that the sample background is clear
of strong U.V. absorbers at 254nm, i.e., no aromatic hydrocarbons other than oil
and grease listed and NO Fe+3 or H
2
S are present. Maximum turbidity allowed
is 1 NTU per 10 ppm oil range up to a maximum range of 0-50 ppm oil (20NTU/
200ppm). When no samples are supplied, TAI will ship unit calibrated with ppm
EPA#2 oil in tap water. In some cases, particularly for very high ranges, a
surfactant such as glycol (non-absorbing, non-interfering) is added to the water
sample which increases the miscibility for the oil to go into solution.
The automatic zero cycle is initiated by a signal from the Model 6600
microprocessor based timer circuit. The timing cycle is 1 hour. The timing cycle
can be modified through the system menu, refer to chapter 3 of the control unit
part of this manual. The zero cycle lasts for about 5 minutes and the sample cycle
lasts about 55 minutes.
The sequential switching from sample to zero is operated by the 6600
control unit, where the zero reading of the output is automatically, hourly
upgraded by the auto zero circuit.
2.5 ZERO CORRECTION FOR CLEAN BACKGROUND
STREAMS (REFERENCE B71441 PIPING)
1. The activation of all solenoid valves in the sample system are performed
by the 6600 timer circuit.
2. Backflush solenoids (sv1, sv2) around the sample cell are used to prepare
a reproducible autozero. These solenoids allow oil free air or nitrogen
(N2), (80-120 psig, 5.62-8.44kg/cm2 g) supply is required to purge out
the cell in reverse flow fashion. This action completely cleans the cell
windows and drys them to a stable reproducible background for the
autozero functioning. Because the process is very clean without impuri-
ties the autozeroing primariy corrects for lamp, detector and particulate
(dirt) accumulation that may occur on the cell windows.
3. When the span filter with its solenoid is selected/programmed and used