Unformatted text preview: nter wire which is gas absorption material. This material contains hydrogen gas. Center wire is wrapped with inert metal tape for protection and the turns of tape allow release of hydrogen gas. Wrapped wire is installed in stainless steel tube and is surrounded with helium gas under pressure. In case of overheat the pressure of helium will increase due to high temp exerts pressure on pneumatic switch at the end of sensor. At preset value switch will close indicates over heat. During fire localized high temp will cause a large quantity of hydrogen gas released from titanium wire cause rise in gas pressure in tube will actuate pneumatic switch. This action is known as discrete function sensor. If helium gas pressure is lost the test circuit warns the flight crew that system is not operational. CONSTRUCTION AND OPERATION OF SMOKE DETECTORS Smoke detection system is used where the type of fire anticipated is expected to generate a substantial amount of smoke before temp changes are sufficient to activate heat detection system. Toxic gases like carbon monoxide or nitrous oxides pressure may takes place due to leak...
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- One '11
- Carbon monoxide, Fire extinguisher, thermo couple