(2)
Detailed description
The FAV contains two main parts :
-a valve body
-an actuator assembly.
(a)
Regulation A thermostat installed downstream of the precooler exchanger senses the hot air temperature and sends to the valve a pressure signal corresponding to precooler cooling air demand. The FAV butterfly takes a position from fully closed to fully open to maintain the temperature value of air bleed within limits.
(b)
Safety devices and indications The FAV is equipped with a test port which serves to perform an "in situ" test. A manual override serves to close the valve mechanically on the ground. Two microswitches in the valve signal the full open and full closed positions of the butterfly. A thermal fuse installed on the valve body closes the valve if the nacelle temperature reaches 450 plus or minus 25 deg.C (45 deg.F).
H. Fan Air Valve Control Thermostat
(Ref. Fig. 029, 030)
(1) The fan air valve control thermostat is installed dowstream of the bleed air precooler exchanger. It controls, through the fan air valve, the engine fan cooling airflow in order to maintain the bleed air temperature to 200 deg.C (392 deg.F) plus or minus 15 deg.C (27 deg.F).
Fan Air Valve (FAV)
Figure 028A
R 1EFF : 004-049, 055-099, 101-149, 151-199, 1 36-11-00Page 99 1201-299, 301-399, 401-499, 1Aug 01/05 1 1 1CES 1
Fan Air Valve Control Thermostat Figure 029
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Fan Air Valve Control Thermostat - Schematic Figure 030
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(2) Detailed Description
(Ref. Fig. 030)
The fan air valve control thermostat contains two mains parts:
-
A temperature sensing element
-
A pressure regulator.
(a) Regulation When the temperature downstream of the precooler exchanger is below the required value:
-the INVAR rod valve remains on its seat
-no air flows through the pressure regulator
-the FAV remains closed. When the temperature is over the required value differential expansion between the INVAR rod and the stainless steel sensing tube opens the rod valve causing the venting of the chamber A and thus allowing a pressure signal through the thermostat to the opening chamber of the FAV.
-Between both values the FAV butterfly has an intermediate position.
J. Bleed Transfer Regulated Pressure Transducers (Ref. 36-21-00)
(1)
The pressure transducer is a piezo-resistive type cell. It senses the bleed transfer/regulated pressure and transforms it into a proportional current voltage.
(2)
Detailed Description
Each pressure transducer consists of :
-
a body with attachment plate
-
a measuring electronic cell
-an electrical connector
-a pressure port.
(a) Operation Operation of both transducers is identical. The pressure to be measured is ducted to the transducer via a sense line. It acts on the integrated strain gage of the piezo-resistive cell to generate an electrical signal proportional to the pressure variation. The signal is transmitted to the bleed monitoring computer.
R 1EFF : ALL 1 36-11-00Page A2 1 1 Aug 01/05 1 1 1CES 1 K. Exchanger Outlet Temperature Sensor (Ref. 36-21-00)
(1)
The sensor monitors the temperature downstream of the precooler. It is a double platinium winding type.
(2)
Detailed Description
The sensor consists of :
-
a housing with a threaded part for installation
-
a sensing element.
-an electrical connector.
(a) Operation The temperature of the bleed air is sensed by the sensing element, transformed into an electrical signal and transmitted to the bleed monitoring computer.
5. Power Supply
____________ **ON A/C 001-049, 051-099, 101-149, 201-299, 301-399,
**ON A/C 001-049, 052-099, 101-105, 201-220, 224-224,
(Ref. Fig. 004) **ON A/C 051-051,
(Ref. Fig. 004A) **ON A/C 106-149, 221-223, 225-299, 301-399,
(Ref. Fig. 004B) **ON A/C 001-049, 052-099, 101-105, 201-220, 224-224,
(Ref. Fig. 005) **ON A/C 051-051,
(Ref. Fig. 005A) **ON A/C 106-149, 221-223, 225-299, 301-399,
(Ref. Fig. 005B)
**ON A/C 001-049, 051-099, 101-149, 201-299, 301-399,
-------------------------------------------------------------------------------BUSBAR VOLTAGE FUNCTIONS ATA NO. AND POWER SUPPLY -------------------------------------------------------------------------------
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