Delta NANOTRACE DF-745 Instruction Manual download pdf (Page 94)

90 Appendix B – Hydrogen Service Safety System

 The pump enclosure must be mounted to a nearby wall or inside the rack shared by

the analyzer. See Figure 86 on page 94.

 The sample gas inlet connection is made to an interlock valve mounted at the sample

gas inlet on the rear of the analyzer. NOTE: The installation of this option changes

the sample inlet connection to female VCR, from male.

 The sample gas outlet is connected by a ¼ inch metal tube from the analyzer sample

outlet, to the needle control valve (supplied loose), and then to the sample inlet on

the pump enclosure.

 A customer supplied and regulated source of nitrogen purge gas is connected to

both the ¼ inch compression fitting on the case purge valve mounted on the rear of

the analyzer as well as to the 1/8 inch compression purge inlet fitting on the vacuum

pump enclosure.

 If required, the pump enclosure sample outlet and/or analyzer sample outlet need to

be connected by ¼ inch metal tube and compression fittings to an appropriate

exhaust system.

 The pump power cord is connected from the rear of the analyzer to the pump

enclosure.

15.4 Operation

 Before power is applied to the analyzer, the moisture cell is in an isolated state as

the internal inlet and outlet valves are closed. In addition, the external sample

interlock valve is closed and the case purge valve is open allowing customer

supplied and regulated Nitrogen gas to purge the analyzer cabinet.

When power is applied, and only after the system has verified proper exhaust fan

operation, the system automatically opens the external sample interlock valve to

enable gas flow and the case purge valve is closed.

NOTE: The back flow prevention screen will be displayed and the user must hit

ESC to acknowledge the screen and remove it.

After approx. 5 minutes, the Warming Up indication will disappear and the user is

then free to open the internal inlet and outlet valves to the moisture cell.

 On analyzer shut-down, or in the event of a power failure or fan failure, the moisture

cell is automatically isolated with internal valves, the external sample interlock valve

closes to block sample flow from entering, and the purge valve opens to allow

Nitrogen purge into the analyzer enclosure.

 The pump case purge system continuously feeds a customer regulated supply of

nitrogen into the pump enclosure to (1) maintain the oxygen level well below the

maximum safe level (5% for hydrogen) in the event that the pump diaphragm fails

and leaks sample gas into the enclosure and (2) maintain appropriate flow for

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Delta NANOTRACE DF-745 Instruction Manual Page 94