DOC AIRBUS | AMM A320FTRANSIENT BLEED VALVE (TBV) SYSTEM - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. General
Compressor Control - Transient Bleed Valve (TBV) System - General (POST SB 72-0169, POST SB 72-0121)
The Transient Bleed Valve (TBV) system consists of the components that follow:
** ON A/C NOT FOR ALL Compressor Control - Transient Bleed Valve (TBV) System - General (POST SB 72-0169, POST SB 72-0121) - TBV (consisting of the actuator, valve and Linear Variable Differential Transducer (LVDT) as a single component)
- Electro-hydraulic servo valve
- TBV ducts.
2. System Description
The TBV system gives additional High Pressure Compressor (HPC) operability margin engine operation. The TBV is normally closed (no 10th stage HPC bleed) and will open to give 10th stage HPC bleed during engine decelerations as the HPC requires additional operability margin. The Electronic Engine Control (EEC) gives actuation control of the TBV through the electro-hydraulic servo valve. A LVDT is part of the actuator to convert the mechanical position of the actuator to an electrical position signal available to the EEC. Only one EEC controls the TBV at any point in time.
** ON A/C NOT FOR ALL The TBV system gives additional High Pressure Compressor (HPC) operability margin engine operation. The TBV is normally closed (no 10th stage HPC bleed) and will open to give 10th stage HPC bleed during engine decelerations as the HPC requires additional operability margin. The Electronic Engine Control (EEC) gives actuation control of the TBV through the electro-hydraulic servo valve. A LVDT is part of the actuator to convert the mechanical position of the actuator to an electrical position signal available to the EEC. Only one EEC controls the TBV at any point in time.
3. Operation
The TBV is installed on the combustor case at the 11 o'clock position forward looking aft. HPC 10th stage air enters the TBV inlet duct and is metered by a butterfly vane positioned by the fuel powered actuator which controls the amount of HPC 10th stage air being bled. Based on the TBV position, the metered air is routed through the TBV outlet duct into a diffuser and is exhausted into the gas path through the TBV exhaust manifold through the Turbine Rear Frame (TRF).
The TBV is installed on the combustor case at the 11 o'clock position forward looking aft. HPC 10th stage air enters the TBV inlet duct and is metered by a butterfly vane positioned by the fuel powered actuator which controls the amount of HPC 10th stage air being bled. Based on the TBV position, the metered air is routed through the TBV outlet duct into a diffuser and is exhausted into the gas path through the TBV exhaust manifold through the Turbine Rear Frame (TRF).