Monday 4th May 2020

Shaft coupling saves fish

The Challenge was to develop a flexible shaft coupling that could be used in the drive assembly of a “Aerator” used in the oxygenation of water in fish spawning ponds and small lakes. Aeration is especially required in times of hot weather where the oxygen concentration within the water can fall and have a detrimental effect on spawning. 

The old procedure involved a fast-rotating agitating propeller, placed below the surface of the water, whilst simultaneously compressed air was piped to just behind the rotating propeller to allow a mix and aeration to take place. Although this original process did work, it was not very efficient as the air hose would often move from the optimum position, requiring constant maintenance and monitoring during operation. In the original design, the immersed propeller was driven via shafting and a series of "cardan style" u-joints, which also required an environmentally friendly lubrication. 

However, it was quickly realised that the drive solution offered by ABSSAC could also aid in the quest to improve aeration.   The Helical beam coupling by design has a hollow centre and this proved to be a big advantage to the application. The final design of Stainless-Steel shaft coupling could not only handle the angular offset and torque required, but cleverly would allow a compressed air tube to be fed through the middle so that oxygen could directly be fed to the middle of the agitating propeller. The end results increased the aeration rate by 30%. 

Moreover, the single piece U-joint design also supported the propeller shaft at the motor end eliminating the need for a bearing. Additionally, the one-piece Stainless-Steel design did not need lubrication or suffer from oxidation.

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