In previous posts, we described testing a 2.75” rotary seal at 1,890,000 PV for 1,000 hours (7,500 psi at 252 feet/minute) and testing a 4.50” rotary seal test at 9,800 psi and 24 rpm. This post describes a 4.5” rotary seal test that was conducted at 9,400 psi while rotating at 120 rpm (141 feet/minute). The duration of the test was 125 hours.
The test was conducted in our new high pressure swivel seal test fixture at 120 rpm using a pair of 4.5” Plastic-Lined Kalsi Seals and an ISO 68 viscosity grade seal lubricant. The fixture tests two seals at a time, exposing each seal to the full pressure. The differential pressure across the seals was maintained at 9,400 psi (64.81 MPa).
The seals are subjected to a larger extrusion gap in this test setup than in the field because pressure acts on only the test shaft outer diameter between the seals. This causes the shaft to deform radially inward by more than 0.001”. In the field, high pressure acts on the shaft bore and the shaft OD between the seals. In this loading the shaft deformation is radially outward. This may seem like a small difference but when sealing high pressure even 0.001” difference in extrusion gap affects seal life.
In addition to the extrusion gap challenge, the fixture provides much less cooling than the seals would receive in an actual high pressure washpipe assembly. We can only circulate 10 GPM through the shaft bore with our test setup. Even with these extra challenges the test seals looked alright at the end of the 125 hour test as can be seen in the photograph.
To achieve this level of performance, we tested our most advanced high pressure rotary seal configuration with our floating backup ring technology, which minimizes extrusion gap clearance. The Plastic-Lined Kalsi Seals that were tested incorporate a highly extrusion resistant liner formed from our -318 material.
The high pressure seal and backup ring technologies are protected by U.S. and foreign patents. To see if these technologies are right for your high pressure seal application, or to request a quote, call us at 281-240-6500 or contact us by e-mail. For available seal sizes, see our shaft seal catalog.