Oilers/Plant Tenders (HHC) Civil Service Practice Exam

Over time, packing material in pumps experiences wear and tear due to the constant friction and pressure it endures during operation. This repeated use leads to significant changes in the material's characteristics. Specifically, the packing material tends to harden and lose its inherent flexibility. When packing is compressed under operating conditions, it may start to dry out or become rigid, making it less effective at creating a proper seal. Maintaining flexibility is crucial for the packing to conform to the shaft and prevent leaks effectively. Therefore, the degradation of the packing's flexibility and the increase in hardness is a common and expected result after repeated use in pumping applications.