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Kalsi Rotary Seal Product Index
Rotary Shaft Seal Styles and Sizes
Kalsi Engineering’s rotary shaft seal product line consists of several patented styles that address a variety of sealing challenges. For the most up-to-date lists of available styles and sizes, click on the links below. For technical information, consult our rotary seal literature, e-mail us, or call us directly with your rotary seal questions at 281-240-6500.
Wide Footprint Seals are interchangeable with standard 0.335'' Kalsi Seals, and provide significantly longer life in abrasive service conditions. They were originally developed for the high pressure sealing location in oilfield mud motor sealed bearing assemblies. The geometry has been optimized to improve environmental exclusion, and to provide more lip width and compression to accommodate wear and compression set, while at the same time assuring efficient hydrodynamic lubrication. For optimum abrasion resistance, lubricant pressure or spring force is recommended to assure optimum seal orientation in the gland.
Axially constrained seals provide improved abrasion resistance in near-zero pressure-differential applications, without the need for axial spring preload. They are recommended for applications such as oilfield mud motor pressure-balancing pistons, where the lubricant pressure may fluctuate slightly above or below the environmental pressure during operation.
The improved performance is the result of constraining the seal axially, as shown below, to assure seal orientation in the gland. For ease of assembly, the seal width is initially narrower than the groove, but radial compression causes the seal to expand axially into stabilizing contact with the groove walls. A lubricant-side void provides room for elastomer thermal expansion to prevent over-confinement at high temperature, so that hydrodynamic lubrication is not impaired. Due to thermal expansion considerations, the groove width is slightly wider than the width that is currently recommended for Standard Kalsi Seals.
High Temperature Kalsi Seals
We have two categories of seal materials that have a higher operating temperature than HNBR. One option is a composite construction that provides a thin layer of FEPM at the dynamic surface, coupled with an FKM seal body. This combines the good dynamic properties of FEPM with the good compression set resistance of FKM. The other option is an FKM developed to have good dynamic properties while retaining good chemical and compression set resistance.
Standard width seals have been tested up to 392°F (200°C) with the composite construction, and up to 380°F (193°C) with the FKM construction. Axially Constrained Seals with a 0.335” radial cross-section have been tested up to 340°F (171°C) with the FKM construction. For available sizes, see the high temperature tables on the axially constrained and standard width web pages.
Standard width Kalsi Seals include the HNBR Basic Kalsi Seal product line, and standard width high temperature seals. The Basic Seal product line is presently undergoing a transition to an upgraded geometry that provides improved lubrication without increasing hydrodynamic pumping related leakage. Only the upgraded geometry is appropriate for high temperature seals. As tooling is upgraded to the new geometry, the seals will be added to the appropriate high temperature seal tables. For optimum abrasion resistance, lubricant pressure or spring force is recommended to assure optimum seal orientation in the gland.
The Enhanced Lubrication (EL) hydrodynamic geometry provides improved seal lubrication and significally reduced running torque in either direction of rotation. Compared to Standard and Wide Footprint seals, an Enhanced Lubrication Seal™ accommodates higher differential pressure conditions with much thinner viscosity lubricants, and can tolerate higher speeds. Enhanced Lubrication Seals have significantly higher hydrodynamic pumping-related leakage than Standard Kalsi Seals. The seals were developed for applications such as high pressure hydraulic swivels, oilfield rotating heads/rotating BOP’s/RCD's, and washpipe assemblies.
Chamfered Enhanced Lubrication Seals were developed for applications where the pressure of the environment is up to 500 psi higher than the pressure of the lubricant. The 674 series has a wide footprint dynamic lip with an exclusion edge chamfer, and is only manufactured in our -11 and -15 HNBR seal materials. Type A enhanced lubrication waves are unsuitable for 674 series chamfered seals. The seals were developed for applications such as oilfield mud pulse systems and low pressure rotating heads.
Hybrid seals mix enhanced lubrication waves with more conventional waves to temper the hydrodynamic pumping-related leak rate while still providing a torque advantage over standard seals. Hybrid seals were developed to provide reduce running torque and seal generated heat in oilfield rotary steerable tools.
Dual Durometer Kalsi Seals
The patented Dual Durometer™ construction provides lower interfacial contact pressure, torque, and heat, compared to single material Kalsi Seals having similar extrusion resistance. The outer part of the seal, which defines the static sealing lip, is made from a relatively soft material to minimize interfacial contact pressure and friction between the seal and the shaft. The inner part of the seal, which defines the dynamic sealing lip, is made from a harder, more extrusion resistant material to bridge higher pressure. Dual Durometer construction can be used with most un-grooved Kalsi Seal geometries, provided that the radial cross-sectional depth is large enough to accept two layers.
By appropriate material selection, the dual durometer seal can be tailored for specific applications. For high pressure applications, the dynamic sealing lip can be made from a harder, more extrusion-resistant material than would otherwise be possible in a solid single durometer seal, while keeping the interfacial contact pressure in a useful range for hydrodynamic lubrication. For moderate pressure applications, the torque and self-generated heat can be minimized while maintaining the necessary extrusion resistance.
For available material combinations, click here. For additional information on Dual Durometer Kalsi Seals, see the Kalsi Seals Handbook. The as molded diameter of a Dual Durometer seal will depend on the molding shrinkage characteristics of the selected material combination. Dual Durometer seals typically require a wider groove than comparable single material seals; call for recommendations.
High Film Kalsi Seals incorporate an aggressive hydrodynamic geometry that provides increased film thickness, lower running torque and cooler operation – at the expense of significantly higher lubricant leakage. In some operating conditions, water can even be used as the seal lubricant. When used with oil, the aggressive geometry can also be used to provide the necessary seal lubrication in ultra-slow speed pressurized equipment. In high speed equipment, the lubricant pumping action of the high film seal can be used to flush and lubricate a series of lip seals; click here for an example.
The Filled Kalsi Seal features a deep environment-end groove that is filled with and bonded to a soft silicone energizer that significantly reduces interfacial contact pressure, torque and self-generated heat, compared to standard Kalsi Seals. The C-shaped construction permits more economical manufacture compared to dual durometer Kalsi Seals, and permits the use of much softer energizing materials because the rotary seal torque is not carried by the energizer. Because filled Kalsi Seals offer increased resistance to compression set and lubricant pressure-induced distortion, they are typically recommended over the older generation Grooved Kalsi Seals. Filled Kalsi Seals are used in high-speed applications such as submersible dredge pumps and oilfield cement pumps. Call for available sizes.
Grooved Kalsi Seals are special purpose rotary shaft seals that employ an environment-end groove that lowers interfacial contact pressure in order to achieve lower breakout and running torque, and less self-generated heat. Grooved seals are not recommended for abrasive environments, or for high differential pressure.