Strategies and Devices for Parametric Testing of Radial Lip Seals
Radial Lip Seal Function and Kinematics
Function: Separates a contained liquid from the external environment while transmitting continuous rotational movement about its axis of symmetry. Tolerates, without leakage, low-amplitude perturbations in the remaining five degrees of freedom.
Shown: Deflected cross-section ...
Parameter |
Governing Equation |
Measurable Quantity |
Scaling Law (Rule of Thumb) |
Typical Range |
Hydrodynamic Pumping | Reynolds: | flow, cc/min (q) | 0.05 - 1.00 | |
Radial Load |
Hoop Stress: |
line force, lb/ circumf in (l) | 5 - 25 | |
Eccentric Load | force, lb (W_{e}) | <2Dl | ||
Static Leakage | Molecular Scale Laminar Viscous Flow | flow, cc/hr | Viscosity on scale of molecular length 10 X normal | 0 - 0.01 |
Parametric Testing Devices and Strategies
Test Device |
General Description | Measurement Domain | Output |
Hydrodynamic Pumping Rig | Device measures volume, as level change in a sight glass, pumped against a specified head in a specified time interval. | Time, fluid volume, pressure, fluid temperature, rotational speed, counterface diameter | Pumped volume as a function of time, fluid viscosity (temperature), speed, and head, normalized by counterface diameter. |
Radial Load Fixture | Split mandrel equipped with load cell measures force to compress halves. | Force, time, counterface diameter | Radial load (lbs per inch of curcumference) as a function of time, max load, min load after specified time, decay rate. |
Eccentric Load Rig | Bearing-mounted counterface capable of specified radial displacement and load measurement. | Force, time, radial displacement, angular location | Max eccentric load curve as function of angular location. |
Static Leakage Fixture | Pressurized cavities, each equipped with a sight glass, measure contained fluid volume change over time, without rotation. | Time, fluid volume, pressure, temperature | Volume change over a specified interval as a function of time. Volume change is corrected for pressure, temperature, and trapped air volume. |
Results — Seal Characterization (continued)
Results — Seal Characterization (continued)
Results — Seal Characterization (continued)
Results — Seal Characterization (continued)