Bal Seal® spring-energized rotary seals

We offer several families of rotary seals suitable for a wide range of temperature and pressure/velocity (PV) applications. Our spring-energized rotary seal solutions include flange seals and seals with metal locking devices. Our high-performance materials offer excellent wear and long life, and our Bal Spring® energizer compensates for lip wear, thermal cycling and tolerance variations. Metal locking rings are available to provide secure installation with low insertion forces.

Types:  Rod, piston, lip, wiper, dust
Sizes:  From 0.031 in. to 75 in. You can find information on large diameter seals here.
Materials:  A list of available sealing materials and their properties can be found here.


Rotary Seal Selection Guide

Type Standard Seal Cross Section (in.) Seal Inside Diameter (in.) Suggested Operating Conditions Features and Benefits
Pressure Range Temperature Range °F (°C) Surface Speed (ft/min) (M/sec)
Uncaptivated Seal Gland (kg/cm2) Captivated Seal Gland (kg/cm2)
KSSx From 0.063 thru 0.125 From 0.125 to 1.000 Pressure* Differential From 15 (1) Vacuum to 3000 (211) Continuous -65° to +350° (-54° to +177°) Intermittent to +550° (+288°) to 3000 (15) • Low insertion force
• Autoclavable
• Best sealing at high temperature
• Longest seal life
KSx From 0.125 thru 0.500 From 1.000 to 34.00
K31x From 0.031 thru 0.125 From 0.063 to 1.000 to 2000 (10)
KF31x From 0.125 thru 0.500 From 1.000 to 34.00
KPx From 0.031 thru 0.188 From 0.063 to 1.000 From 7 (0.5) to 15 (1) to 7500 (38) • Low friction 
• Long life 
• Good sealing 
• High temperature
KPFx From 0.094 thru 0.500 From 1.000 to 14.00
RS31x From 0.031 thru 0.500 From 0.063 to 75.00 Not applicable Vacuum to 3000 (211) to 3000 (15) Better sealing 
• Lower cost 
• Requires retaining
S31x From 0.016 thru 0.500 From 0.020 to 12.00 Not recommended to 25 (1.8) Continuous -20° to +200° (-29° to +93°) Intermittent to +250° (+121°) to 250 (1.3)
71x From 0.063 thru 0.500 From 0.063 to 14.00 Vacuum to 60 (4) to 750 (4) • Moderate cost 
• Good sealing
PBx From 0.063 thru 0.500 From 0.063 to 14.00 to 15 (1) to 1000 (5) • Compatibility with most fluids 
• Lowest cost 
• Low friction

This selection guide represents only a small portion of the many rotary seal solutions that we offer.

For high pressure/velocity

Our LKS® high PV seal delivers reliable, consistent performance and unprecedented levels of service life and predictability. The innovative, multi-component LKS seal offers exceptional protection against leakage in harsh media, temperatures, pressures and speeds.

Under high pressures and velocities, the LKS seal guards against extrusion of the seal jacket material by supporting it in hardware with little or no clearance between the seal and rotating shaft. The seal's unique design forces the wear pattern of the jacket material to take place at the lip contact area, not the hinge point.

Features Benefits
All-in-one configuration Eliminates costly assemblies/assembly error, simplifies maintenance and replacement, provides compatibility with conventional gland configurations
Built-in thermoplastic anti-extrusion element Minimizes seal jacket extrusion, provides longer sealing life, forces wear to occur at lip contact area, not hinge point, extends seal performance range at low and high temperatures (-94 to +550 ºF).
Graphite-reinforced PTFE sealing ring Retains ability to seal in high-temperature, high pressure service conditions at moderate speeds, provides high level of extrusion resistance, long-wearing properties and built-in lubricity.
Bal Spring® canted coil spring Exerts uniform sealing force against the shaft, lowers frictional contact at the lip area (reducing heat build-up and extending seal life), provides excellent corrosion resistance/chemical compatibility.


Built on more than 25 years of sealing experience, the LKS® can help improve the reliability and performance of equipment. The multi-component LKS combines innovative design and material science with proven Bal Spring® energizer technology to give you 150% more service life and an increased level of protection against warranty claims. Here are some examples of typical applications used throughout the oilfield industry:

Rotary Steerables

rotary steerable image

A rotary steerable system is programmed by the directional driller, who transmits commands using surface equipment. The tools interpret the commands, and gradually steer in the desired direction. Continuous rotation of the drill string allows for improved transportation of drilled cuttings to the surface. In this application, the LKS® creates a barrier and keeps rock, oil, mud and sand from entering the tool and damaging hardware.

Pump Systems

pump systems image

Pumps and pump systems rely on seals to protect costly bearings from damage and contamination. In these applications, the LKS® creates a barrier between the harsh mud, sand, oil, H²S, water and other contaminants that can impede or even prohibit the operation of the bearings, motor and other critical components. The LKS seal also helps guard against adverse environmental impact by minimizing the possibility of external leakage.

Top Drives

top drive image

Today’s more aggressive drilling and exploration practices place an added level of demand on top drives, the units that provide rotational force to the drill string. A typical top drive assembly houses a wash pipe that allows drilling mud from the shaker to travel down the center pipe. The LKS seal's primary role in this application is to prevent the leakage of drilling mud from the top drive assembly.

Pulsing Tools

pulsing tool image

Many oil and gas wells are drilled directionally, and techniques known as “logging while drilling” (LWD) and “measurement while drilling” (MWD) allow important information about the drilling process to be continuously transmitted to the surface. MWD logs use mud pulse technology to send data from the tools on the bottom of the drill string to topside processors. The LKS seal prevents fluid, mud, sand, rock and H²S gas from entering the mud pulser casing, and it also helps keep moisture from migrating into the tool’s sensitive electronics.


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