SLIDING WEAR STUDIES OF PUMP LINER MATERIAL (GCI 26) BY POD TRIBOMETER
Keywords:Rotary piston vacuum pump, liner, GCI 26, Sliding wear test, POD tribometer
Rotary piston vacuum pumps are used in NFC, Hyderabad in large numbers to create vacuum in various systems and furnaces. Due to continuous operation, the liner component of the pumps got worn out resulting in failure in achieving the required vacuum. Efforts were made to repair and refurbish of the pumps by the manufacturer. By metallography, the liner material was found that pump material was gray cast iron (GCI 26). An extensive pin-on-disc experiment was carried out for three loads namely 0.5, 1 and 2 kg for a sliding distance of 1000 m. Two set of sliding velocities 2 and 3 m/s were chosen. GCI 26 showed high friction and wear under dry conditions. It is observed that as the speed increases the coefficient of friction also increases. Use of the vacuum pump for prolonged duration promoted wear leading to deterioration of clearance between the rotary cam and the liner, there by degrading vacuum in the corresponding chamber.
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