Supply Plus Ltd designs, manufactures, supplies and distributes safety and fuel delivery equipment, with brands including AS Fire & Safety, Bayley and Collins Youldon. They approached us to design a rotary seal to replace their existing solution which was causing leakage during downtime.
The application
Supply Plus initially approached us with a requirement for their 2” Swing joint power spindle.
In this application, the outlet pipe from the fuel tank on delivery vehicles feeds into the centre of a rotating hose reel (located between the tank and cab of the vehicle). An electric motor powers the reel and pumps the fuel through at relatively low pressure.
The customer’s main issue with the existing design was leakage. This is from the hose fitting in low temperatures especially at -25°C during winter, and when vehicles were parked over-night.
The challenges
The 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. We established that a standard spring energised rotary seal would not work in the application; a bespoke design was required.
The leakage at night when vehicles were not in use suggested the issue was worsened when the seal was both cold and not energised. Therefore, we designed a rotary seal that would remain energised at low temperatures and low pressure.
Our sealing solution
Our engineers designed a simple but effective seal. It incorporated a large heel in the base of the housing that 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 specified a low temperature Viton to ensure the seal retained elastomeric properties. It also applied the sealing force at low energising pressures and very low temperatures. This combination provides excellent resistance to fuel oils, diesel and aviation fuel.
