Heat Transfer Fluid Deposit in Retainer of Mechanical Seal

Mechanical seals in industrial pumps play a critical role in preventing heat transfer fluid leakage, especially under high-temperature operating conditions. A key component of this system is the seal head, which functions as a compression mechanism through a spring to maintain contact between sealing surfaces. However, the spring's performance can deteriorate due to the accumulation of deposits resulting from prolonged exposure to elevated temperatures, operating pressure, and fluid degradation—ultimately leading to seal failure and fluid leakage. This study aims to investigate the thermal stability of the reservoir fluid Therminol 66 (TM-66) and its impact on seal performance under long-term thermal exposure. The methodology includes direct observation of failed seals, thermogravimetric analysis (TGA) at temperatures of 75, 150, 250, and 350 °C for durations of 3, 6, and 12 hours, and chemical characterization using Fourier Transform Infrared Spectroscopy (FTIR). Additionally, thermal degradation behavior was assessed through activation energy estimation based on weight loss data obtained from TGA. FTIR results revealed that phenylcyclohexane is the dominant compound in TM-66, with a relative intensity of 0.803119. The thermogravimetric data demonstrated that higher temperatures and longer exposure times significantly accelerated fluid evaporation and mass loss. The activation energy analysis confirmed that thermal degradation is more likely to occur under extended high-temperature conditions. These findings highlight the importance of maintaining reservoir fluid temperature below 75°C to minimize deposit buildup in the seal chamber and ensure the long-term reliability and efficiency of the mechanical seal system.