Dynamic Seal Test Rig: O-Ring Leakage and Sliding Friction Measurements

Abstract

Sliding seals play a critical role in the dynamic sealing of a wide-variety of machinery applications. There are many type of sliding seals, such as segmented carbon ring, O-ring, or bellows; and are used as sealing elements in hydraulic rod and piston seals, as well as secondary sealing elements in mechanical and dry-gas seals. Motion between the dynamic and static parts of the machine is most often lubricated by the process fluid, and therefore has leakage. This paper presents a new test rig capable of measuring leakage and friction force of annular sliding seals for a range of sealing pressures (0–24.8 MPa), temperatures (20–700 C), gasses, and motion. The rig is capable of large linear motions and high frequency dynamic motion. The large linear motion replicates piston movement or shaft thermal growth and the dynamic excitation matches the typical vibration response from a spinning shaft. Currently, there is little available information in the literature on the leakage performance of dynamic O-rings at high pressures, especially for gas sealing. The paper presents experimental results from two different material, 150 mm diameter, O-rings at sealing pressures up to 70 bar (1,000 psi) in CO2. The rings were tested for large ranges of motion, up to 4 mm. Two different durometer FKM O-rings (70 and 90) were compared to a 70 durometer BUNA O-ring. The softer rings exhibited superior leakage performance, and similar friction forces. The BUNA O-ring performed slightly better at sealing (10–20%) then the similar hardness Viton ring.

Gasket Solutions for Electrolyzers – An Overview

“…In this respect, the required forces increase accordingly when not only two plates, but perhaps 100 plates are pressed together. Nielson (2022) A corresponding approach to solving this problem is profiling to increase the contact surface pressing force, as shown here in Figure 3.…”