High Pressure Side Port Swivel Design
Using Kalsi Seals in High Performance Side Port Swivels
The image below illustrates how to design a side port swivel with Kalsi-brand rotary shaft seals for extreme high pressure sealing (half of the swivel is shown). In this swivel design, stacking housings locate our patented floating backup rings, which self-align on the mandrel, and float laterally to follow runout. This allows the smallest practicable extrusion gap clearance between the metal backup rings and the mandrel without risk of heavily loaded metal-to-metal contact. The small extrusion gap clearance allows the rotary shaft seals to achieve their maximum high pressure performance potential. This seal and backup ring combination provides hundreds of hours of operation at 10,000 psi with a 4.500” mandrel rotating at 120 to 175 rpm. In a similar arrangement, 1,000 hours of operation has been achieved at 7,500 psi with a 2.750” mandrel rotating at 350 rpm.
Overview of the Recommended High Pressure Side Port Swivel Design
In the swivel design below, the partitioning seal separates the seal lubricant from the high pressure process fluid that is flowing though the swivel. The pressure of the seal lubricant is slightly higher than the pressure of the process fluid, to keep the partitioning seal properly oriented for optimum abrasion resistance. There are various ways to pressurize the lubricant.
The floating metal backup rings are axially force balanced and radially pressure balanced for dimensional stability and freedom of lateral movement. They are located between partitioning seal and bulkhead housings that are are bolted to the central housing. (If desired, the features of the partitioning seal housings can be incorporated in the central housing.) Axially short pilots between housings provide excellent alignment with no risk of binding during assembly.
The bearing housings are bolted to the bulkhead housings. This isolates the bearing housings from the pressure induced expansion experienced by the other housings, which helps to minimize dynamic runout of the mandrel.
The assembly is based on parts that are relatively easy to machine, and avoids all use of radial O-rings, which increase assembly difficulty and are failure prone in high pressure conditions.
Additional swivel design information is provided in our shaft seal handbook. Contact our staff for detailed engineering guidance, design review, backup ring licensing information, and seal purchasing assistance.