Shaft coupling provides double role for pond aeration device
03 May 2012
A challenge Abssac faced recently was to develop a flexible shaft coupling that could be used in the drive assembly of an 'aerator' used to oxygenate 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 a shaft and a series of 'cardan' style U-joints, which also required an environmentally friendly lubrication.
Abssac was asked to come up with a method of replacing the universal joints so that no lubrication would be required. Abssac suggested a helical beam coupling, which has a hollow centre, and this proved a very useful feature for the application. The stainless steel shaft coupling was not only able to handle the angular offset and torque required, but it also allowed a compressed air tube to be fed through the middle so that oxygen could be fed directly to the middle of the agitating propeller. This increased aeration rate by 30%.
Moreover, the single piece U-joint design also supported the propeller shaft at the motor end, avoiding the need for a bearing.
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