SKF Industrial Seals — range, types and replacement guide

SKF industrial seals cover four broad families — power transmission seals, hydraulic (fluid power) seals, fluid handling seals and machined seals — supported by a materials programme spanning elastomers, polyurethanes, thermoplastics and PTFE compounds. This page maps the range as an engineer meets it in the field: what each family does, the type designations you will find stamped on the part, the design data that matters when specifying a replacement, and how the machined-seal route covers sizes that no catalogue holds.

How the range is structured

SKF's sealing business grew from several acquisitions and the naming still reflects that. CR Seals, part of SKF since 1990, supplies the radial shaft seal (oil seal) programme and is the origin of the CR part-number prefixes still quoted daily in the aftermarket. Tenute, acquired in 2022, added heavy industry, wind power and marine sealing. The Judenburg-based SEAL JET system covers machined seals. In practice this means one physical seal can be described three different ways — by a legacy CR number, by a current SKF designation, and by a profile code from the machined-seal catalogue.

Power transmission seals

The rotary programme is the largest and the one most often replaced on a shutdown. A radial shaft seal sits between a rotating shaft and a static housing, its lip loaded by a garter spring, and controls lubricant retention outwards and contamination ingress inwards. SKF splits the offer into general industrial, heavy industrial and low cross-section variants.

Radial shaft seal designs

Counterface and housing data

Most premature radial shaft seal failures are counterface failures. Before ordering a replacement, check the following against the shaft and housing as found, not as drawn.

Hydraulic and fluid power seals

The hydraulic programme treats a cylinder as a system rather than a list of parts: a buffer seal ahead of the rod seal to take pressure spikes, the rod seal itself for the main duty, a wiper to exclude contamination, guide rings to carry side load and keep metal apart, and static seals at the head and gland.

Selection is driven by pressure, speed, stroke length, duty cycle, temperature, fluid type and the level of external contamination. High pressure with slow, long strokes favours PTFE-based low-friction sets; rapid short-stroke service with side load favours polyurethane with generous guide-ring area.

Fluid handling seals

Spectraseal valve stem seals and wellhead seals sit at the severe end of the range: fugitive-emission-controlled valve stems, high pressure, sour service and wide temperature swings. These are engineered sets rather than catalogue items, typically combining spring-energised PTFE or thermoplastic sealing elements with anti-extrusion and bearing components. Where an equivalent is needed, the enquiry has to carry media, pressure, temperature, and any emissions or material certification requirement, not only the dimensions.

Machined seals and the SEAL JET route

The machined-seal programme turns seals from stock billet on CNC machines instead of moulding them in dedicated tooling. Practically, that removes the two constraints that hurt maintenance engineers most: tooling lead time and diameter limits. Almost any profile, in almost any diameter, can be produced from a drawing or from a worn sample — including large-diameter rings well beyond moulded tooling capacity.

• Obsolete sizes withdrawn from the moulded catalogue
• One-off and small-batch cylinder repairs, where tooling cost cannot be justified
• Very large diameters — hydro turbines, presses, marine and wind equipment
• Prototype and development builds, where the profile is still changing
• Material substitutions, keeping the profile but changing to a higher-temperature or chemically resistant grade

Sealparts works the same way for our own lines — see seal prototyping and small-batch production for how a worn sample becomes a finished ring.

Materials

The material families used across the industrial seals range are the same four groups you will see on any manufacturer's data sheet; what differs is the compound designation, so always transfer the grade, not just the polymer name, when cross-referencing.

Cross-referencing and replacing SKF seals

In the aftermarket you will rarely be handed a clean designation. Work through the following in order.

• Read the seal. Radial shaft seals usually carry shaft diameter × outside diameter × width and a design code on the case or the rubber face. Inch-series CR numbers encode shaft size in hundredths of an inch.
• Measure the part, not the hole. A pressed-out seal may have relaxed or distorted; verify against the housing bore and shaft journal with a micrometer.
• Establish design, not just size. Single lip, dust lip, rubber OD or metal OD, spring or springless, and handedness for hydrodynamic patterns.
• Capture service conditions. Speed, temperature, fluid, pressure and contamination decide the compound, and are the usual reason a dimensionally identical replacement fails early.
• Consider the counterface. If the shaft is grooved, a wear sleeve is normally cheaper and faster than a shaft repair.

How Sealparts helps

We are not an SKF distributor. We work with engineers who need the correct seal for a machine, whatever the original brand: we identify the part from a sample, a drawing or a worn seal, cross-reference it against the Japanese and European ranges we hold, and where nothing standard exists we machine it. That includes hydraulic rod, piston and wiper sets, rotary shaft seals, guide rings, back-up rings and O-rings.

• Japanese equivalents and machine tool seals — see finding replacements for NOK, Sakagami and machine tool seals
• Specifying from first principles — how to specify and buy a seal for a new application
• Send a sample or a sketch through the enquiry form and we will come back with a profile, a material and a lead time.

SKF, CR Seals, Speedi-Sleeve, Spectraseal, Mudblock and SEAL JET are trademarks of AB SKF. This page is independent editorial reference material for engineers identifying and replacing industrial seals; Sealparts Ltd is not affiliated with, endorsed by, or an authorised distributor for SKF. Product structure summarised from SKF's published industrial seals pages.