Zero Cycle - Ametek 5920 UHP User Manual

Zero Cycle

The function of the first purifier (located between DV2 and DV3) is shown in
Figures 1-5 and 1-6. Essentially, the first purifier provides a separate source of
dry gas that is used to verify the baseline readings for the analyzer and to com-
pensate for any small offsets that may be present. This process in analogous to
using a "tare" on an analytical balance or a blank solution on a spectrometer.
In a Zero cycle, DV1 is closed and DV2 and DV3 are open. The flow of the
sample gas from the analyzer inlet is diverted through the first purifier. As a
result, the operating states in Figures 1-5 and 1-6 are similar to those of normal
operation (Figures 1-2 and 1-3) except that the sample gas passes through the
first purifier. After completing the timed Zero cycle, the 5920 compensates for
any minor offsets and the analyzer returns to normal operation.
Zero Sample Gas
IN
DV1
DV2 DV3
Purifier
OPEN
CLOSED.
D V = Diaphragm Valve
S V = Solenoid Valve
MFM = Mass Flow Meter
Figure 1-5.
Zero sample gas flow.
PN 592047901 Rev YC
AMETEK recommends performing a Zero every 24 hours for the first
month of operation. After this start-up period, the analyzer will have
dried down sufficiently to increase the Zero interval to 1 week. AMETEK
recommends that the duration of the Zero cycle be set to 48 (i.e., 2
hours).
Zero Sample Gas A
Sample Gas
Pressure
Regulator
SPLIT
Zero Sample Gas B
SV3
MFM
Sample Gas Flow/Path
Reference Gas Flow/Path
Sensor
DV4
Purifier
Overview
SV1
SV2
|
1-9