Delta Faucet DF-745 Manuel D’Utilisation

Appendix B – Hydrogen Service Safety System                 DF-745

The Hydrogen Service Safety System is designed to safeguard the DF-745 from 
explosion hazards when operating on hydrogen sample gas under normal pressure and flow 
conditions as described in this manual. The instrument chassis and the remote pump, if 
equipped, are both protected by maintaining a safe condition within their respective 
enclosures.

If equipped with this option at the time of shipment from the factory, the analyzer will be set
for Hydrogen operation through the GSF screen and the Hydrogen Safety Service System 
will automatically be enabled.



Air circulation fans pull air in through the front door (and vent through the rear) of 
the chassis.  The fans are rated at 50 cfm  (125 cfm max) which will maintain the 
internal chassis space below the lower explosive limit (LEL)

1

. 



Sample delivery interlock valve blocks flow of sample gas from entering the 
instrument chassis under various conditions as described below.  It consists of a 
normally closed pneumatically actuated UHP springless diaphragm valve positioned 
on the sample inlet bulkhead.



Analyzer case purge valve introduces nitrogen purge flow into the chassis upon 
closure of the sample delivery interlock valve.  It consists of a normally open 
pneumatically actuated valve which feeds a customer supplied and regulated source 
of nitrogen purge gas through a bulkhead on the rear of the cabinet. 

2

   



3

default, manage and actuate the above mentioned 

components to maintain safe operating conditions.



If equipped with a vacuum pump, an enclosure equipped with a nitrogen case purge 
is provided for the vacuum pump to maintain a safe condition. In addition, an 
interlock is provided to detect and react to loss of Nitrogen purge flow. See Figure 
86 on page 94.

If equipped with this safety system, the analyzer installation procedure is modified as 
follows: