For humid and water environment conditions, which EPB bearings should be selected, and will performance be affected by water absorption?

The EPB series specifically divides material groups for humid environments and underwater applications. Some grades have low water absorption and good dimensional stability in humid environments, while ordinary general-purpose plastics tend to swell and seize after absorbing water and cannot be used directly underwater. For humid environments, prefer EPB1, EPB2, EPB16, and EPB18; for long-term underwater motion, prefer EPB8 and EPB20. EPB2 is suitable for medium-low load, humid, high-volume, low-cost equipment, -50~100°C, low water absorption; EPB16 has high strength and low water absorption, -40~130°C, and maintains dimensional stability in humid environments; EPB8 is a dedicated underwater grade, with underwater wear resistance far superior to dry friction, -40~200°C, and can operate under heavy load in chemical liquids; EPB20 is suitable for underwater medium-low load high-speed rotation. Note: underwater-specific materials such as EPB8 and EPB20 perform poorly in dry friction and cannot be used dry. Water absorption changes bearing dimensions. Low-water-absorption grades can suppress this phenomenon, but long-term immersion still requires prototype testing. Typical scenarios: water treatment valves, pharmaceutical bottle washing machinery, and underwater transmission mechanisms. Pharmaceutical bottle washing grippers extensively use EPB4, which resists cleaning liquid, moisture, and corrosion. In humid conditions, try to avoid ordinary EPB base grades; water absorption and swelling will reduce fit clearance and cause shaft seizure/jamming.