Wiring arrangement for protecting a bleed air supply system of an aircraft against overheating and bleed air supply incorporating such a wiring arrangement
View Patent ↗A wiring arrangement for protecting a bleed air supply system of an aircraft against overheating is associated with a bleed air supply system. The bleed air supply system includes a bleed air source, a bleed air feed, a shutoff valve arranged in the bleed air feed and a leakage monitoring device with a monitoring control device, which is connected via a shutoff circuit to the shutoff valve in such a way that the shutoff valve is closed when the shutoff circuit is interrupted. The wiring arrangement includes a thermal switch, which is connected in series with the shutoff valve and the monitoring control device to the shutoff circuit and which, once a predetermined limit temperature has been exceeded, interrupts the shutoff circuit.
1. A wiring arrangement for protecting a bleed air supply system of an aircraft against overheating, the bleed air supply system comprising a bleed air source connected to an aircraft engine, a bleed air feed, a shutoff valve arranged in the bleed air feed and a leakage monitoring device with a control device, which is connected via a shutoff circuit to the shutoff valve in such a way that the shutoff valve is closed when the shutoff circuit is interrupted, the wiring arrangement comprising:
a thermal switch in thermally conductive contact with the bleed air feed, which is connected in series with the shutoff valve and the control device in the shutoff circuit and which, once a predetermined limit temperature has been exceeded, interrupts the shutoff circuit, and wherein the thermal switch is connected directly between the shutoff valve and the control device in the shutoff circuit.
2. The wiring arrangement according to claim 1 , wherein the bleed air feed also comprises at least one pipe and the thermal switch is in thermally conductive contact with a surface of the at least one pipe.
3. The wiring arrangement according to claim 1 , wherein the thermal switch is a mechanical switch.
4. The wiring arrangement according to claim 1 , wherein the predetermined limit temperature is approximately 300° C.
5. The wiring arrangement according to claim 1 , wherein the bleed air supply system also comprises a cool air supply system, wherein the cool air supply system supplies cool air.
6. The wiring arrangement according to claim 5 , wherein the bleed air source and the cool air supply system are connected thermally to one another via a heat exchanger, the bleed air feed also being connected to the heat exchanger, and the thermal switch being arranged directly downstream of the heat exchanger in the bleed air feed.
7. The wiring arrangement according to claim 1 , wherein the thermal switch is designed as a double switch with two switching levels.
8. The wiring arrangement according to claim 7 , wherein one of the two switching levels of the thermal switch formed as a double switch is connected to ground below a critical temperature.
9. The wiring arrangement according to claim 8 , wherein the critical temperature is 300° C.
10. The wiring arrangement according to claim 7 , wherein one of the two switching levels of the thermal switch formed as a double switch is not connected to ground above a critical temperature.
11. The wiring arrangement according to claim 7 , wherein one of the two switching levels of the thermal switch formed as a double switch is connected to a fault signal lamp.
12. The wiring arrangement according to claim 7 , wherein one of the two switching levels of the thermal switch formed as a double switch is connected to a flight warning system.
13. A bleed air supply system, comprising the wiring arrangement of claim 1 .