Product category:
Industrial Drives/Controls
News Release from: ABB Automation Tech (Drives and Motors) | Subject: ABB 75kW drive
Edited by the Engineeringtalk Editorial
Team on 26 January 2006
Drive gets to the bottom of borehole
problem
Hired drive used to investigate cloudy water at a borehole owned by South Staffordshire Water.
Cloudy water at a borehole owned by South Staffordshire Water has been investigated with the help of a hired ABB drive, supplied by ABB Drives Alliance member Central Electrical South Staffordshire Water was experiencing problems with water extracted from its borehole at Sandhills, near Lichfield
This article was originally published on Engineeringtalk on 8 Feb 2000 at 8.00am (UK)
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Although the water quality was adequate, aeration of the water was causing a cloudy appearance, which water customers found unacceptable.
The water company approached Central Electrical for help in conducting tests on the borehole.
Central Electrical responded, setting up a mobile variable speed drive at the site within 24 hours.
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Supplied under Central Electrical's hire drive scheme, the 75kW drive was put to work pumping water from various depths in the borehole to investigate the problem.
South Staffordshire Water wanted to determine if the pump or the borehole itself was the source of the problem.
If it was the pump, then cavitation could be causing the aeration of the water.
If it was the borehole, then this could potentially be a much more serious problem, involving expensive repair work.
To resolve the problem, the old shaft driven pump was removed together with the jointed rising main, eliminating the 40 plus pipework joints on the pump suction.
A submersible pump set was then installed that would change the characteristic of the pump borehole rising main to that of a positive pressure, also eliminating the prospect of air being drawn into the rising main.
Bob Harding, Automation Systems Engineer for South Staffordshire Water, said: "The borehole could be pumped at various output flows, allowing us to assess the risk of air pollution at various flows and pressures".
The drive was needed to lower the standing water level for a camera survey, which revealed that the actual problem was dissolved oxygen in the water.
There were no structural problems in the borehole and the borehole did not require relining.
Harding said: "Using the hire drive saved us time and cost, and helped us eliminate the major possible causes of the aeration".
"We showed that it was not due to the water level going lower than the inlet of the shaft driven water pump and letting air in, and the variable speed drive proved that pumping at various speed and depths also made no difference".
"The problem seems to be a characteristic of the borehole itself - oxygen is introduced into the water because of the geometry and chemical characteristics of the lining of the borehole".
South Staffordshire Water now needs to work out how to solve the problem..
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