Application Note: Raising And Lowering Mixers In Wastewater Treatment

Several Thern 57 Series Fre-Rol cranes are used at this wastewater treatment plant in Wisconsin to position mixers. The crane is operated with a 4WS Series electric winch to raise and lower the mixer into position along a guide rail attached to the wall of the mixing tank. A secondary tie off supports the mixer once it is in position. The crane boom adjusts with a ratchet style screw jack allowing the operator to keep the end of the boom centered over the mixer. This helps to avoid side pulls which cause the mixers to bind on the guide rails.