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 e-mail, or by fax at 281-240-0255.
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|
|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|
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™.