Edwards B777-01-000, Instruction Manual

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Technical Data
B777-00-880 Issue E
2.3 Vent gas specification and vent control data
Although the pump may be vented to atmosphere, relatively high air humidity may greatly increase the subsequent
pump-down time. To reduce pump-down times you should vent the pump with dry, clean gases.
2.4 Purge gas specification
2.5 Water cooling
The following water cooling specification corresponds to a typical high quality drinking water specification. Check
with your water supply authority if you are in doubt about the quality of your supply.
Table 2 - Vent gas and vent control data
Vent gas system items Reference data
Vent gas Dry air, nitrogen, argon or other inert gases
Maximum dew point at atmospheric pressure -22 °C
Maximum size of particulate 1 micron
Maximum concentration of oil 0.1 parts per million
Time for rotational speed to reach 50% >15 seconds
Maximum allowed rate of pressure rise see Figure 3
Table 3 - Purge gas specification
Purge gas system items Reference data
Purge gas Dry nitrogen, argon or other inert gases
Maximum dew point at atmospheric pressure -22 °C
Maximum size of particulates 1 micron
Maximum concentration of oil 0.1 parts per million
Allowable purge gas flow (when required) 20 to 150 sccm (0.33 to 2.48 mbar l s
-1
,
33 to 248 Pa l s
-1
)
Recommended purge gas flow 25 sccm (0.42 mbar l s
-1
, 42 Pa l s
-1
)
Maximum allowable purge gas supply pressure 2 bar gauge (29 psig, 3 x 10
5
Pa)
Table 4 - Cooling water specification
Cooling water system items Reference data
Quality Mechanically clean and optically with no deposits
or turbidity
pH value 6.0 to 8.0
Maximum calcium carbonate concentration 75 parts per million
Maximum chloride concentration 100 parts per million
Minimum oxygen concentration 4 parts per million
Recommended water cooling flow rate (at 15 °C) 15 l hr
-1
Water temperature See Table 5
Maximum water pressure 5 bar (gauge), 73.5 psig, 6 x 10
5
Pa
Materials exposed to cooling water Copper, brass, braise