Delta NANOTRACE DF-745 Instruction Manual download pdf (Page 24)

20 DF-745 Installation, Start Up and Shut Down

The moisture cell outlet will be connected to the supplied aspirator or, if equipped, to the

vacuum pump.

The sample inlet to the moisture analyzer, as well as the zero gas inlet, are heated to 60 C.

This is done to mitigate any effects of adsorption-desorption of trace moisture on the walls

of the tubing.

4.2.2 Gas Pressure and Flow Settings

Attention to the setting of gas pressure and flow is critical to proper operation of the

analyzer. If all steps are followed carefully at the time of start up, subsequent changes to

flow or background gas will be made easier. The following procedure assumes all electrical

and plumbing connections have been made according to instructions in this manual. In

addition, this procedure assumes a Nitrogen gas background unless otherwise noted.

1. Power up the unit. See page 19. If the unit is equipped with a Hydrogen Safety

System, no flow will enter the system until the unit is on power.

2. Ensure that the needle valve on the aspirator is fully open.

3. For a basic analyzer with no cell isolation valves installed,

a. simply provide sufficient pressure (5-30 psi), resulting in a flow of 1 slpm (2

scfh) as indicated on the flow meter located behind the front door. NOTE:

The flow rate will directly impact the overall system speed of response.

b. 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) NOTE: Once the vacuum source is

connected and running, proper flow is indicated by a full scale reading on the

flowmeter.

c. Go to step 5.

4. For analyzers equipped with optional cell isolation valves:

a. Completely open (turn fully clockwise) the inlet regulator on the rear of the

analyzer. For operation in Nitrogen, Argon and Oxygen the regulator is

closed (turned counter clockwise) to the approximate middle, or 50% of its

range. For operation in Helium and Hydrogen it should be closed to 80-90%

of its range resulting in a flow of 1 slpm (2 scfh) as indicated on the flow

meter located behind the front door. NOTE: The flow rate will directly

impact the overall system speed of response.

b. Open the flowmeter bypass valve on the rear of the analyzer and flow in the

bypass loop will be indicated on the flowmeter. Adjust the flowmeter bypass

valve to 0.5 slpm. See Figure 5.

c. Purge for 15 minutes before opening gas valves to the moisture cell.

d. The state of the gas control valves is indicated on the main display. The

default state of a factory-shipped instrument is isolation. This can be

adjusted in the Power Up Default section. If the moisture cell is isolated,

establish process flow via the Main menu. See page 38.

1 2 ... 19 20 21 22 23 24 25 26 27 28 29 ... 97 98

No comments

Delta NANOTRACE DF-745 Instruction Manual Page 24