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B73567AMT
18th Jun 2004, 05:27
Can anybody explain how this is done?
Are there any airliners (Airbus, Boeing, Douglas) that incorporate them?

Any help would be appreciated.

Thanks

farqueue
8th Jul 2004, 17:05
Since no one else has stepped up to the plate.

There are two common variants of this. The most common is a bleed orifice and a set of return lines. Any air will rapidly vent out via the small hole, but the oil flow rate is much, much smaller. You MUST be able to support a small flow rate for this system. Oh, and the orifice has to be at the top of the item you are bleeding.

The other is used in dead-end parts to work the air back against the main flow. This is done by a series of chambers in the line. Fluid flows in at the top, out at the bottom. Any air is held in the chamber and when the pressure reduces it vents back to the chamber down the line. It will take many cycles to clear any significant volume of air from the system. The advantage is that it can be used without a flow source, but the max presure will drop with any air in the system, until it has been totally cleared.