DEVELOPMENT OF AIRCRAFT STANDARD 'FLOW SWITCH ASSEMBLY' (INDIGENOUSLY) FOR THE RADAR COOLING SYSTEM (RCS) OF TYPICAL FIGHTER AIRCRAFT

摘要

The Flow switch assembly is provided in Radar cooling system to monitor the flow status in the system. This unit is used in Aircraft to operate an electric circuit when flow in the system reaches a predetermined value. This unit basically consists of two main parts one is differential pressure switch and second one is Flow venturi. When the flow takes place inside the venturi, fluid goes through HP port as well LP port, based on pressure in the line. When the differential pressure crosses a predetermined value, the movement of bellow assembly operates a micro switch to change the state. The operating differential pressure is between 15 mbar to 35 mbar. Controller monitors the flow status and in turn gives feed back to Mission Computer. The design requirements of the Flow Switch is as follows, change the state of position of Micro Switch during increasing flow: before 10 1pm, during decreasing flow: between 7 to 4.50 1pm, Max Flow rate: 16 1pm. Medium: Coolanol-R25. Working temperature range is -40 to 80℃, Max operating pressure is 7.5 bar 'g' Space Envelope 80mm dia X 100mm, Weight is less than 350gms. The design is according to the requirements of Environmental Standard, MIL-STD-810D. The acceptance tests such as the Dimensional check, Measurement of weight, PI check etc and Qualification tests such as the Random vibration test, Acceleration test, Endurance tests are successfully done according to the standards, which demonstrate the functionality within performance specification limits and under simulated environmental conditions. In every stage of development there is an involvement of Quality Assurance Department (QA), Chief Resident Inspector (CRI), Regional Centre for Military Airworthiness (RCMA), and all the necessary approvals of Drawings, process sheets, Test Documents etc have been taken and all test reports have been prepared, which authenticates that the unit is functioning satisfactorily as per the Airworthiness requirement.