Presentation Profile
Use of a Newly Designed Shear Stability Tester to Study Lubricants Subjected to Mechanical Shearing
Currently Scheduled: 10/12/2022 - 9:40 AM - 10:00 AM
Room: Convention Center Walkway
Main Author
Raj Shah - Koehler Instrument Company, Inc.
- Nicole Turner - Hofstra University
- Stanley Zhang - Koehler Instrument Company, Inc.
Abstract:
Proper lubrication is critical for maintaining the integrity of industrial equipment and instrumentation. Majority of multigrade lubricants contain viscosity modifiers to raise the viscosity index (VI) and ensure that the lubricant can form a sufficiently thick coating to protect machinery from various forms of degradation. The majority of viscosity modifiers (VM) are composed of polymers that are vulnerable to shear thinning. Shear thinning can reduce the viscosity of a lubricant by an entire ISO grade, therefore putting moving parts at risk of deterioration. To guarantee the fluid’s viscosity is stable, shear stability tests are conducted to evaluate the fluid’s characteristics under shear stress and temperature changes. Determining the shear stability of a fluid is the capability of an oil or lubricant to maintain its viscosity characteristic over a series of applications due to mechanical shearing. The nature of these tests, describes the effects shearing has on viscosity parameters, whether change in temperature differences or on recurrence of machine use. Such use has the chance to result in a decrease in acceptance values for that specific fluid. When fluids and lubricants are subjected to varied temperature changes, testing methods are performed to ensure those of high viscosity index are still acceptable when placed under mechanical shearing. The newly designed Shear Stability Tester is an instrument designed to test oils and other fluids under shearing on intervals of 30 cycles up to 120 cycles starting from 0. Based on the results from each test, oils that experience a smaller viscosity reduction during the course of the test are considered to have greater shear stability compared to oils with a relatively significant decline. This poster discusses the new instrument and the ASTM technique developed to measure shear stability.
