Delta NANOTRACE DF-745 Instruction Manual download pdf (Page 25)

Installation, Start Up and Shut Down DF-745 21

e. Use the regulator to adjust the flow through the cell to 1 slpm (2 scfh) as

shown on the flowmeter behind the front door. NOTE: This flow rate may

be reduced to minimize gas consumption but the flow rate will directly

impact the overall system speed of response.

f. Confirm that the needle valve on the vacuum source (aspirator) is fully open

(CCW).

g. Turn on the vacuum source (aspirator) by applying gas to the high pressure

inlet. See Figure 3. (Except when measuring in Helium background which is

not run under vacuum but at ambient)

5. At this point, some adjustment of the aspirator needle valve may be necessary to

achieve the necessary operating cell pressures for each gas (except Helium where

there is no vacuum operation). The proper pressure ranges listed in Table 1 will

automatically appear on the display when the GSF is selected.

Background Gas

Pressure

Vacuum Source

150

250 Torr

280

380 Torr

740

780 Torr

OFF

300

0 Torr

300

400 Torr

*A shut off valve must be installed at the inlet to the aspirator to disable the vacuum.

Table 1: Recommended Sample Outlet Vacuum Pressure

4.2.3 Download System Data

The final step of the installation, after a couple days of dry down, should be to download

the system data (see page 65), and send them by e-mail to service@delta-f.com for review.

This will allow the factory to confirm that the analyzer is working properly by comparison

with data stored at the time of shipment, and in addition will set a baseline for comparison

with future downloads, if any.

4.3 Analyzer Shut Down

In order to minimize the time required for the analyzer to re-achieve a zero baseline on start

up, the following steps should be followed when shutting the analyzer down.

Short Term Shut Down - A short-term shut down, for example to move and restart the

analyzer, can be accomplished by simply shutting off the power switch behind the front

door. This action initiates the standard isolation process (for analyzers equipped with gas

control valves) and computer shut down which takes approximately 40 seconds.

Long Term Shut Down – For analyzers with gas control valves, from the Main Menu go

to System, and select Isolate Analyzer. A routine automatically starts that closes the

downstream valve and allows pressure to build in the moisture cell after which an upstream

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Delta NANOTRACE DF-745 Instruction Manual Page 25

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