Servomex NanoTrace DF-760E, Инструкция по эксплуатации

Страница: 178 / 182

174 DF-760E Appendix B – Hydrogen Service Safety System

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 aspirator. If the analyzer has the optional vacuum pump, 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, and also, if equipped with the vacuum pump, to the 1/8 inch
compression purge inlet fitting on the vacuum pump enclosure. Using the customer
supplied regulator adjust the flow into both enclosures to approx. 30 scfh as
indicated on a rotameter.

If required, the pump enclosure sample outlet and/or analyzer sample outlets 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 rear of the
pump enclosure.
15.4
Operation

Before power is applied to the analyzer, the moisture cell and oxygen sensors are
isolated 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 (see page 31) 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 and oxygen
sensor.

On analyzer shut-down, or in the event of a power failure or fan failure, the
moisture cell and oxygen sensor are 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.