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发表于 2010-6-12 02:06:14
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来自： 中国广东汕头
1,发动机引气，APU引气，地面气源。
2当发动机工作在大功率状态时，引气是从高压压气机第五级获得。当发动机工作在慢车和低功率状态时，因为第五级引气压力低而由高压级活门控制自动转至由高压压气机第九级供气。
3 Pressure Regulator and Shutoff Valve (Fig. 4) ____________________________________
A. The pressure regulator and shutoff valve (PRSOV) is a pneumatically
actuated, spring loaded closed, butterfly type valve. The valve, in
conjunction with a remotely mounted bleed air regulator, provides
pneumatic signals to open, close, and regulate pressure for downstream
bleed air.
B. The valve consists basically of an actuator, manual override with closed
position lock, and flow body with a butterfly plate.
C. Pressure regulated bleed air, routed from the remotely mounted bleed air
regulator, supplies air to the control pressure connection Chamber B at a
constant reference pressure level, independent of the upstream pressure
variation. The reference pressure in Chamber B overcomes the spring
force, causing the valve to start opening. Then, as bleed air flows
downstream of the valve and is routed to Chamber C through the downstream
sense connection. The valve continues to open until downstream pressure
force in Chamber C and spring closing force are balanced by the reference
pressure in Chamber B. Any further change in downstream pressure, due to
changes in valve upstream pressure or downstream flow demand, will cause
the valve to modulate to maintain downstream pressure at a nominal 42
psig.
D. Shutoff operation occurs whenever Chamber B pressure is reduced below 10
psig. At this point, spring force and Chamber C residual pressure will
force the valve to close.
E. The valve may be manually locked in closed position by rotating the
manual wrenching hex (butterfly shaft) so that the lock screw/position
indicator aligns with closed position, loosening lock screw/position
indicator and then sliding the detented locking knob into the recess in
the retainer plate. The manual lock is retained in the override position
by retightening the lock screw/position indicator. Also the valve may be
unlocked by loosening the lock screw/position indicator, centering
detented locking knob in the retainer plate, sliding detented locking
knob out of the recess in the retainer plate, and then retightening the
lock screw/position indicator
4，在P5-10面板的中间是隔离活门操作电门
，操作
：C. With the isolation valve switch in AUTO, engine bleed switches ON and
pack switches in AUTO or HIGH, the isolation valve will stay closed. If
either of the four switches is put to the OFF position, power is
transferred to turn open the isolation valve. This operation must be
manually performed as the circuit passes through the switch, not the
affected valve.
D. The other two positions, OPEN and CLOSE, function as a conventional
switch regardless of pack and bleed switch positions.
5 双引气灯（DUAL BLEED）亮指示APU引气活门打开并且一号发动机引气电门置于“ON（接通）”位或者二号发动机引气电门置于“ON（接通）”位和隔离活门电门置于“OPEN（打开）”位。在航线维护时，机组经常反映在起动发动机后，关闭APU引气电门，双引气灯亮。根据MEL只要能确认是信号问题，而不是APU引气活门没有关闭，是可以放行的。
6，引气温度调节
当发动机工作时，接通引气电门，PRSOV打开，从发动机引出的高温高压的空气进入活门，通过控制活门开度，使得流出活门的空气压力和温度控制在454PSI和450F（232C），空气然后进入预冷器，预冷器控制活门控制着从发动机风扇后引来的空气去冷却引出空气，使得引出空气的最大正常供气温度控制在450F （232C ）。
预冷器控制活门传感器的温度值为41525F（21314C）。预冷器控制活门在390F（190C）或以下时完全关闭，在440F（227C ）或以上时完全打开。 |
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