Plastic Backup Ring Sizes

Our patented laterally floating metal backup ring technology allows a high-pressure shaft seal to operate for extended periods by providing the smallest practical extrusion gap clearance. The technology is applicable to many different types of equipment, such as cementing heads and other side port process fluid swivels, coaxial and side port hydraulic swivels, rotary control devices, washpipe assemblies, etc.The metal backup rings can float laterally to follow shaft runout because they are axially force balanced. This force balance is caused by the pressure of the seal lubricant acting on equally sized hydraulic areas defined on the ends of the metal ring by face sealing O-rings. These O-rings are susceptible to extrusion-type damage in extreme pressure conditions due to the pressure itself, and due to pressure-induced equipment deformation. Our patented plastic O-ring backup rings prevent extrusion damage by bridging the gap between the metal backup ring and the mating equipment surfaces. This ensures that the O-rings do not become the weak point of the rotary sealing assembly.

The plastic backup rings have a much lower coefficient of friction, compared to O-rings. This facilitates lateral motion of the metal backup ring, and reduces motion-induced wear of the metal backup ring. For additional information on how these technologies can be used to address your high-pressure rotary shaft sealing challenges, contact Kalsi Engineering.

Additional backup ring sizes can be furnished upon request. Purchase orders and requests for backup ring quotes should be sent to the attention of Seal Sales via fax at 281-240-0255, or by e-mail.

Plastic backup rings prevent O-ring damage in high pressure rotary shaft seal assemblies, such as coaxial and side entry swivels. The O-ring energized plastic backup rings define equally sized hydraulic areas on opposite ends of the metal backup ring. The resulting axial force balance allows the metal backup ring to “float” laterally to follow shaft runout while defining a very small clearance for the rotary shaft seal. The small clearance allows the rotary shaft seal to perform to its full pressure potential.

 

Table 1: Plastic backup rings for the outer balancing grooves

Shaft Diameter, Inches Part Number Groove Outer Dia, Inch Groove Radial Width, Inch Groove Axial Depth, Inch Use With This O-ring
2.750 712-3-* 4.507-4.512 0.212-0.222 0.130-0.134 2-243
2.750 712-2-* 4.632-4.637 0.212-0.222 0.130-0.134 2-244
4.500 712-9-* 6.040-6.045 0.212-0.222 0.130-0.134 143mm x 3.5mm
4.500 712-10-* 6.145-6.150 0.212-0.222 0.130-0.134 147mm x 3.5mm
8.434 712-6-* 9.970-9.975 0.212-0.222 0.130-0.134 243mm x 3.5mm
8.434 712-5-* 10.126-10.131 0.212-0.222 0.130-0.134 2-273 or 247mm x 3.5mm

* The complete part number consists of the number given in the table plus the material dash number (-32, -33 or -35).

Table 2: Plastic backup rings for the inner balancing groove

Shaft Diameter, Inches Part Number Groove Inner Dia, Inch Groove Radial Width, Inch Groove Axial Depth, Inch Use With This O-ring
2.750 712-1-* 2.953-2.958 0.212-0.222 0.130-0.134 77.5mm x 3.55mm
4.500 712-11-* 4.670-4.675 0.212-0.222 0.130-0.134 2-248 or 121mm x 3.5mm
8.434 712-4-* 8.659-8.664 0.212-0.222 0.130-0.134 2-269 or 222mm x 3.5mm

* The complete part number consists of the number given in the table plus the material dash number (-32, -33 or -35).

Updated: August 12, 2020

Kalsi Seals are offered for sale under the terms and conditions of the “Offer of Sale” that is included in the current revision of the Kalsi Seals Handbook.

 

Our Kalsi Seal Team is standing by to meet your high pressure rotary shaft seal needs. Call them today for technical assistance, or to request a quote.
Our Kalsi Seal Team is standing by to meet your high pressure rotary shaft seal needs. Call them today for technical assistance, or to request a quote.