Nutrien Rocanville Potash: Design of Impeller Removal Tool
David, Toluwaniyin Joshua
Prime Consulting has been tasked to design an impeller removal tool to replace the current process at Nutrien's Rocanville potash operation. The existing process involves wrapping a sling around the seized impeller and using the crane to screw the impeller off of the pump shaft. This process introduces hazards to the employees, as there is a risk that the impeller will fall out of the sling, potentially coming into contact with an employee or nearby equipment. Additionally, this process is time consuming and requires operators to be in near-constant interaction with the impeller. The objectives of this project were to design an impeller removal tool which is able to remove the 12/10, 10/8, and 8/6 impellers from their respective pump shafts. The tool must do. while reducing the risks posed to the operators as compared to the existing process. Additionally, the tool should require no more than two operators and may only utilize a 25-tonne overhead crane and forklift to support the process. The tool should be able to complete the job in a similar or shorter amount of time than the current process takes. Finally, the ability to break the torque of the seized impeller would be considered a favourable, but not required, design feature. With the input of Nutrien's engineering and operations team, Prime Consulting underwent a conceptual design process, concept screening and scoring, concept combination, and finally an iterative design process to arrive at a final design. The final design is powered by a 5 kN.m pneumatic torque wrench and transmits the torque through a shaft to which a clamp is attached. The clamp is capable of securing all three impeller sizes to the tool. The design also features a scissor-lift table to adjust the height of the tool and wheels to allow the tool to be easily transported around the shop floor. The final design weighs a total of 926 lbs and has a total cost to purchase and fabricate of [redacted]. When compared against the needs and specifications of the project, the impeller removal tool meets or exceeds all marginal specifications and outperforms the existing process in the highest importance needs. The impeller removal tool is expected to reduce the risk posed to operators during the operation of removing seized impellers, and increase the overall productivity of Nutrien's Rocanville operation.