Ametek Western Research IPS-4, User Manual

Page: 71 / 238

Installation and Start-Up | 3-23
Start-Up and Verification
This section describes equipment and controls on the analyzer system that
require adjustments and settings before, during, and after power-up.
Figure 3-1 illustrates the locations of analyzer equipment and controls
that require adjustments for a typical Zone 1 analyzer layout. Refer
to Final “As Built” drawings for settings specific to your analyzer
system.
Purged Analyzers
The Electronics Enclosure and its Optical Bench and Measuring Cell
Extension are continuously purged with Instrument Air to adequately
dilute any flammable gases that may have been released into these areas.
This function effectively prevents an internal explosion when the ana-
lyzer is powered up and operating under normal sampling conditions.
AMETEK analyzers that require purged enclosures in hazardous locations
use an Expo Technologies MiniPurge
®
System With eTimer to perform this
function.
The purge air supply is normally obtained from the Instrument Air supply
connected directly to the Expo MiniPurge
®
System. The required purge air
supply pressure for your analyzer is indicated on Final “As-Built” draw-
ings in the analyzer Documentation Package.
After the Instrument Air supply has been connected to the MiniPurge
®
system, the ALARM/PRESSURIZED indicator on the MiniPurge
®
system
(Figure 3-1) turns from RED (Alarm condition) to GREEN (Pressurized).
Next, the system’s eTimer begins its purge timing cycle, and the four
PURGE TIMING indicator LEDs will flash (YELLOW) sequentially, each
for 25 % of the total purge time (minimum 15 minutes). During this stage,
the MiniPurge
®
system will purge any flammable gases that may have
entered the Electronics Enclosure while its door was open, and then pres-
surize the enclosure. After the timing sequence is completed (LEDs off),
the pneumatic switch will send a signal to the analyzer and the analyzer
will power up (if the Purge Bypass Switch is in the “
ACTIVE ” position, if
all fuses have been engaged, and if the external explosion-proof power-
disconnect switch has been closed).

NOTE