Sealing Tech

Get Quote

Rotary Seals

Rotor seals provide sealing functionality for rotating and swiveling movements under high pressure and low velocity. There are two different types of rotary seals: for the stator with dynamic sealing on the inside, and for the rotor with dynamic sealing on the outside diameter of the seal. Except for end seals in rotary distributors, rotor seals are designed for double-acting functionality.

Rotary sealing set Prädifa series RS

Rotary sealing set Prädifa series RS

Thermal Application Type: High Temperature (< 205 C) °C, Low Temperature (< -35 C) °C, Standard moderate Temperature (-35 C to 100 C) °C

Media: Hydraulic

Polymer Material Options: Nitrile Butadiene Rubber (NBR, XNBR), Fluorocarbon Rubber (FKM, FPM), Hydrogenated Nitrile Butadiene Rubber (HNBR, HSN)

Maximum Operating Pressure: 500 bar

Minimum Operating Temperature: -50 to -10 °C

Maximum Operating Temperature: 100 °C

Maximum Surface Speed: 0.5 m/sec

Unit of Measure: Length: mm

Cushioning Mechanism: No

Pressure Rating: Extremely High Pressure (> 500 bar) bar

The RS rotary sealing set consists of a high-strength thermoplastic slide ring with particularly stable thermal properties and an elastomer preloading element. The special contact surface geometry at the inner diameter of the slide ring with the patented (EP 0 643 243 B2) alternating pitch has a major beneficial effect on the lubrication of the seal. This has a positive impact on both friction and wear. The preloading element responsible for the static sealing function has a rectangular cross section. Compared to O-rings, this has advantages with regard to contact load (sealing) and deformation behaviour (pumping inside the groove). The dynamic interior sealing method is preferable. We do not recommend a dynamic exterior sealing arrangement. The slide ring compound used and its geometry allow use of the seal even under maximum permissible pressure (and in case of pressure peaks) without requiring additional anti-extrusion rings. At the same time, it is possible to take maximum advantage of the diameter play between rotor and stator without any functional impairment. In principle, the seal can also be used as an exterior end seal. In case of doubt, however, we recommend our C5 or C9 product series.

  • Enhanced sealing performance in non-pressurized conditions.
  • Robust seal profile for harshest operating conditions.
  • Extreme wear resistance.
  • Long service life thanks to application-optimized compounds.
  • Insensitive to pressure peaks.
  • Improved lubrication due to pressure medium deposit in the dynamic contact area.
  • Extremely high extrusion resistance.
  • Installation in closed and undercut housings.

Range of application:

  • Primarily for alternating sealing of rotary applications in rotating tracks, pivot drives, hose reels, and in machine tool hydraulics.
Rotary seal Prädifa series OR

Rotary seal Prädifa series OR

Media: Hydraulic

Polymer Material Options: Polytetrafluoroethylene (PTFE, mPTFE, TFM, Polon®), Ultra-High Molecular Weight Polyethylene (UHMWPE), Thermoplastic Polyurethane (TPU, Resilon®, Ultrathan®)

Maximum Operating Pressure: 300 bar

Minimum Operating Temperature: -260 to -25 °C

Maximum Operating Temperature: 80 to 300 °C

Maximum Surface Speed: 1, 0.5 m/sec

Unit of Measure: Length: mm

Cushioning Mechanism: No

Thermal Application Type: Extremely High Temperature (> 205 C) °C, Standard moderate Temperature (-35 C to 100 C) °C, Expanded Low and High Temperature (< -35 C to 140 C) °C

Pressure Rating: High Pressure (< 500 bar) bar

The internally sealing OR sealing set featuring a Slipper Seal® design consists of a PTFE rotor sealing ring and an elastomer O-ring as a pre-loading element.

It is particularly suitable for alternating sealing of rotary transmissions for slewing rings, swivel drives, hose reels, and in machine tool hydraulics. If the sealing set is used as an end seal, it is recommended to install a double wiper ring at the end of the components. Due to the special operating conditions of rotary transmissions, the OR rotor sealing sets are provided with one or two circumferential lubrication grooves.

Due to the material combination of the slide ring (PTFE) and O-ring (elastomer), this product is suitable for a wide range of applications, especially for aggressive media and/or high temperatures. Alternatively, several compounds can be selected, depending on the specific applications profile.

  • Good sealing performance in extremely small assembly conditions.
  • Excellent wear resistance.
  • Minimal break-away and dynamic friction and no stick-slip tendency ensures uniform motion even at low speeds.
  • Good energy efficiency due to low friction.
  • Insensitive to pressure peaks.
  • High temperature resistance assured by suitable O-Ring compound selection.
  • Improved lubrication due to pressure medium deposit in the dynamic contact area.
  • High extrusion resistance.
  • Adaptable to nearly all media thanks to high chemical resistance of the sealing ring and large O-Ring compound selection.
  • Short axial assembly length.
  • Installation in closed and undercut housings.
  • Available in diameters from 4 to 3000 mm.
  • Further dimensions of machined series with short lead times available
  • For More Information
Rotary sealing set Prädifa series KA

Rotary sealing set Prädifa series KA

Media: Hydraulic

Polymer Material Options: Nitrile Butadiene Rubber (NBR, XNBR)

Maximum Operating Pressure: 400 bar

Minimum Operating Temperature: -30 °C

Maximum Operating Temperature: 100 °C

Maximum Surface Speed: 0.2 m/sec

Unit of Measure: Length: mm

Cushioning Mechanism: No

Thermal Application Type: Standard moderate Temperature (-35 C to 100 C) °C

Pressure Rating: High Pressure (< 500 bar) bar

The KA rotary sealing set is a compact seal for sealing the high-pressure channels of rotary transmissions. It consists of a rubber element with a fabric-reinforced running surface and two anti-extrusion rings. They increase stability and prevent extrusion into the gap which – due to the rotary motion (eccentricity) – is variable in most cases. Due to the special shape of the dynamic sealing area, a lubricant deposit is formed which ensures the preservation of the liquid film and thereby prevents dry running.

  • Enhanced sealing performance in non-pressurized conditions.
  • Robust seal profile for harshest operating conditions.
  • Extreme wear resistance.
  • Insensitive to pressure peaks.
  • High temperature resistance in case of suitable compound selection.
  • Extremely high extrusion resistance.
  • Installation in closed and undercut housings.

Range of application:

  • Mainly for applications where the pressure alternates from one side of the seal to the other, such as pivots for rotating track rings, swivel joints, hose reels, and in machine tool hydraulics.
Rotary seal Prädifa series C5

Rotary seal Prädifa series C5

Media: Hydraulic

Polymer Material Options: Nitrile Butadiene Rubber (NBR, XNBR)

Maximum Operating Pressure: 400 bar

Minimum Operating Temperature: -30 °C

Maximum Operating Temperature: 100 °C

Maximum Surface Speed: 0.2 m/sec

Unit of Measure: Length: mm

Cushioning Mechanism: No

Thermal Application Type: Standard moderate Temperature (-35 C to 100 C) °C

Pressure Rating: High Pressure (< 500 bar) bar

The C5 rotor seal is a compact seal for use as an end seal for low-pressure channels in rotary transmissions. The one-piece and therefore axially short C5 rotor seal is ideally suited for this application. For pressures above 10 bar, we recommend the C9 rotor seal.

  • Easy installation.
  • Installation in closed and undercut housings.

Range of application:

  • Mainly for use as an end-seal in all rotary transmissions of construction machinery, mobile hydraulics and machine tool hydraulics, as well as for low pressure swivel joints.
Rotary sealing set Prädifa series OQ

Rotary sealing set Prädifa series OQ

Inside Diameter: 18 to 893,4 mm

Outside Diameter: 13.1 to 877,9 mm

Media: Hydraulic

Polymer Material Options: Polytetrafluoroethylene (PTFE, mPTFE, TFM, Polon®), Thermoplastic Polyurethane (TPU, Resilon®, Ultrathan®), Ultra-High Molecular Weight Polyethylene (UHMW-PE)

Maximum Operating Pressure: 300 bar

Minimum Operating Temperature: -260 to -25 °C

Maximum Operating Temperature: 80 to 300 °C

Maximum Surface Speed: 1, 0,5 m/sec

Unit of Measure: Length: mm

Cushioning Mechanism: No

Thermal Application Type: Standard moderate Temperature (-35 C to 100 C) °C, High Temperature (< 205 C) °C

Pressure Rating: High Pressure (< 500 bar) bar

The externally sealing double-acting OQ rotor sealing set featuring a Slipper Seal® design consists of a PTFE rotor sealing ring and an an elastomer O-ring as a preloading element. It is particularly suitable for alternating sealing of rotary transmissions for slewing rings, swivel drives, hose reels, and in machine tool hydraulics. If the sealing set is used as an end seal, it is recommended to install a double wiper ring at the end of the components. Due to the special operating conditions of rotary transmissions, the OQ rotor sealing sets are provided with one or two circumferential lubrication grooves.

Due to the material combination of the slide ring (PTFE) and O-ring (elastomer), this product is suitable for a wide range of applications, especially for aggressive media and/or high temperatures. Alternatively, several compounds can be selected, depending on the specific applications profile.

From the perspective of application engineering, internally sealing rotor seals (see RS, OR, KA product series) are the preferred choices.

  • Excellent wear resistance.
  • Minimal break-away and dynamic friction and no stick-slip tendency ensures uniform motion even at low speeds.
  • Good energy efficiency due to low friction.
  • High temperature resistance assured by suitable O-ring compound selection.
  • Adaptable to nearly all media thanks to high chemical resistance of the sealing ring and large O-ring compound selection.
  • Dimensions according to DIN ISO 6195, Type D.
  • Installation in closed and undercut housings.
  • Available in diameters from 4 to 3000 mm.
  • Machined small-volume series and samples available with short lead times.

Range of application:

  • Recommendation for rotary transmissions: P × v ≤ 25 (40)
C9_zm

Rotary seal Prädifa series C9

Media: Hydraulic

Polymer Material Options: Nitrile Butadiene Rubber (NBR, XNBR)

Maximum Operating Pressure: 6 bar

Minimum Operating Temperature: -25 to -10 °C

Maximum Operating Temperature: 80 °C

Maximum Surface Speed: 0,2 m/sec

Unit of Measure: Length: mm

Cushioning Mechanism: No

Thermal Application Type: Standard moderate Temperature (-35 C to 100 C) °C

Pressure Rating: Low Pressure (< 160 bar) bar

The C9 rotor seal is a compact seal for use as an end seal for low-pressure channels in rotary transmissions. It consists of a wear-resistant basic rubber element and an anti-extrusion ring which increases stability and prevents extrusion into the gap which may be variable due to eccentricity and the rotary motion. The sealing element was designed specifically as an end seal and, due to the layout, is able to withstand higher pressure peaks. For pressures below 10 bar, we recommend the C5 rotor seal.

  • Insensitive to pressure peaks.
  • Installation in closed and undercut housings.

Range of application:

  • Mainly for use as an end-seal in all rotary transmissions of construction machinery, mobile hydraulics and machine tool hydraulics, as well as for low pressure swivel joints.
Rotary-Seals_CFN_PTD_zm

Polymer Material Options: Polytetrafluoroethylene (PTFE, mPTFE, TFM, Polon®)

Division: Prädifa Technology Division

Industry: Automotive, Oil & Gas, Aerospace, Pharmaceuticals, Food & Beverage, Semiconductor, General Industrial

Brand: Prädifa

Maximum Operating Pressure: 160 bar, 2300 psi

Product Type: Rotar Seals

Minimum Operating Pressure: >16 bar, >250 psi

Technology: Sealing & Shielding

Maximum Surface Speed: >5 m/sec, >17 ft/sec

For Fluid Type: Broad Range

FlexiCase® rotary seals are designed to seal the most demanding rotary applications seals. They feature an inner diameter lip that seals dynamically on a shaft and a metal casing on the outer diameter to seal statically with a press-fit into a bore. A gasket is positioned between layers of sealing lips and the casing to seal off the potential leak path and to compensate for differential expansion. Usually, FlexiCase® seals are not spring-energized. Consequently, the radial lip contact forces are lower than those of rotary FlexiSeals®, which allows the seal to function at much higher surface speeds.

Features/Benefits:

  • Surface speeds up to 70 meters/secon
  • Pressure resistance up to 35 bar
  • Temperature resistance from -100 °C to 250 °C and more
  • Diameters up to 2,000 mm
  • Very good chemical resistance thanks to PTFE sealing element
  • Low frictional energy loss and friction-related heating
  • Unlimited shelf life thanks to PTFE sealing elements
  • Long seal life in dry and abrasive conditions (with wiper elements)
  • Single- or double-acting operation
  • Uni- or bi-directional rotation

Range of Application:

The combination of a robust metal casing with special PTFE compounds makes the FlexiCase rotary seal suitable for use in conditions of extreme temperatures, surface speeds and chemical attack, such as those typically occurring in compressors, special pumps, hydraulic motors, etc.

  • For More Information