Rotary seals for heavy duty transportationSupply Plus Ltd designs, manufactures, supplies and distributes safety and fuel delivery equipment, with brands including AS Fire & Safety, Bayley and Collins Youldon. The application  Our customer, Supply Plus approached us with a requirement for their 2” Swing joint power spindle. The outlet pipe from the fuel tank on delivery vehicles is fed into the centre of a rotating hose reel. This is located between the tank and cab of the vehicle. This is powered by an electric motor and pumped through at relatively low pressure. The current design experienced issues of leakage from the hose fitting in low temperatures especially at -25°C, and particularly when vehicles are parked overnight. Therefore we recommended a rotary seal for this heavy duty transportation. The challenges This application required a rotary seal with low temperature capability and excellent resistance to oil-based fuels. A design was required to replace the existing seal in the available housing between the rotating metal faces. Therefore a standard spring energised rotary seal would not work in the application; a bespoke design was required. Leakage at night when vehicles are not in use often means the issue worsens because the seal is cold and not energised. Therefore, we designed a rotary seal for heavy duty transportation that would remain energised at low temperatures and low pressure. Our sealing solution Our engineers designed a simple but effective seal, incorporating a large heel in the base of the housing. This energised a lip sealing on a rotating metal face. The volume of rubber in the heel of the seal, combined with the 170° angled base, created sufficient force to maintain a seal at low pressure. We used a low temperature Viton ensuring the seal retained elastomeric properties and applied the sealing force at low energising pressures and very low temperatures. This also provided excellent resistance to fuel oils, diesel and aviation fuel. We tested prototypes at both an in-house test unit and in the field over four winter months. Results showed no issues during dispense of fuel and a complete cessation of leakage. The seal was approved and production orders placed, and the design has been incorporated across additional sizes of hose reels. Learn more about our rotary seals HERE