High-Temp Radial Seal of Atlas Copco RD22U in Saudi Arabia

Ma'aden's phosphate processing complex at Wa'ad Al Shamal in northern Saudi Arabia and the gold mining operations in the Mahd Ad Dahab region operate drill equipment in an environment where ambient air temperature at 10:00 AM in July already exceeds 42°C. The RD22U's rotation motor radial seal runs against the motor shaft at a sliding velocity that generates frictional heat on top of the ambient. At 42°C ambient with a hydraulic oil return temperature of 85–90°C arriving at the motor housing, the seal lip temperature—accounting for frictional heating—reaches 100–115°C continuously. NBR radial seals are technically within their 120°C intermittent limit at that condition, but 'intermittent' means occasional events, not a 10-hour drilling shift.

Standard NBR compound loses 25–30% of its tensile strength at 110°C sustained exposure compared to its 20°C baseline. The seal lip contact force—which depends on the elastomer's elastic modulus maintaining its design value—drops proportionally. As contact force reduces, the oil film at the shaft-seal interface thickens slightly, the shaft surface is wetted rather than wiped, and a gradual oil trace begins at the seal face. The trace appears intermittent at first, then consistent, then the shaft scores from contaminated oil circulation in the now-compromised zone.

Radial Seal Material Performance at Saudi Operating Temperatures

Saudi Aramco's equipment standard for drill operations above 38°C ambient specifies HNBR rotation motor seals as the minimum grade—a threshold that Saudi drilling sites exceed for 8 consecutive months annually. The HNBR compound's superior heat aging resistance means a seal changed at 450 hours comes out with its elastic properties largely intact rather than heat-hardened. HOVOO supplies RD22U HNBR radial seal kits for Saudi Arabia and high-temperature markets globally. Full references at hovooseal.com.