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Rotary Seals

Rotary seals close the gap between a rotating or oscillating shaft and its housing, preventing leakage of oil, grease and working fluids and the ingress of dust and water. Typical designs include lip seals, where the lip contacts the shaft, and combination types in which an energizer (a resilient elastomer that presses against the seal) pushes a PTFE slide ring against the shaft. Single-acting (single-pressure) designs withstand pressure from one direction, while double-acting (dual-pressure) designs can separate pressure or fluids from both sides. Spring-loaded and springless versions are available, as well as split types for plummer blocks. Applications include rotary joints on machine tools, rotary pivots, bearing protection in chemical and pharmaceutical equipment, and agricultural machinery.

How to choose Rotary Seals

  1. 1. Select a size that matches the shaft diameter

    Select seals to match the diameter of the shaft on which they are installed. Listed products cover a shaft diameter range of 5 to 1000 mm, and the applicable range differs by type. Shaft tolerance and surface roughness also affect sealing performance and wear, so check the recommended groove dimensions together with the shaft diameter.

  2. 2. Confirm the peripheral speed is within the limit

    Sliding speed is evaluated as the peripheral speed calculated from shaft diameter and rotational speed. The listed upper limits range widely from 0.2 to 25 m/s, and higher speeds make lips and slide rings more prone to wear from frictional heat. Choose a product with a margin above the actual peripheral speed, for example from PTFE spring-loaded types recommended for low friction and high speed.

  3. 3. Match the pressure rating and single- or double-acting design

    The maximum operating pressure of listed products is 5 to 400 bar. Springless lip seals are mainly intended for grease retention and foreign matter exclusion and are not suitable for high pressure. For rotary joints and rotary pivots subject to high pressure or pressure from both sides, consider double-acting PTFE seals combined with O-rings.

  4. 4. Select materials suited to temperature and fluid

    Rubber-based materials such as NBR offer excellent elasticity, while PTFE offers superior chemical resistance, heat resistance and low friction. PTFE is often selected for chemical and pharmaceutical applications and high-temperature environments. Check that the O-ring material of the energizer is compatible with both the operating temperature range and the fluid used.

  5. 5. Check the cross-section dimensions for the groove

    Cross-section dimensions range from 0.85 to 10.5 mm and must match the width and depth of the housing groove. When replacing existing equipment, match the cross-section dimensions as well as the shaft diameter, and confirm that the squeeze is appropriate.

  6. 6. Determine whether a split design is required

    Split designs that can be divided into two halves are available for plummer blocks, allowing replacement without removing the shaft and reducing maintenance effort. When using a one-piece type, confirm during the design stage whether it can be inserted from the shaft end and whether chamfers or tooling are provided to avoid damaging the lip.

This guide was written by AI based on the listed products' documents and specification items. Check each manufacturer's documents before adopting.