Equalizing Cooling Tower Cold Water Basins
Multiple 'open' cooling towers that share common inlet/outlet piping must have some means of keeping the cold water basin levels reasonably close to one another. Without equalization, it is common to see one basin emptying while its neighbor overflows. With multiple towers, the flow rate into one tower rarely matches the exiting flow. Suppose, for example, there were two unequalized towers with shared inlet/outlet piping each designed for 1,000gpm. Due to slight differences in piping lengths, clogged nozzles, dirty strainers or whatever, the water actually enters one tower at 1,000gpm but exits at 1,020gpm. The basin would run out of water at the rate of 20gpm and could be empty in short order. Simultaneously, the adjacent basin would overfill at 20gpm and begin to overflow.
An equalizer is simply a generously sized pipe or flume connecting the basins together forcing the levels to be nearly the same.
Some towers are essentially two or more towers connected together in the field with flumes (typically a rectangular sheet metal pipes about one foot long) between them. They are cheap to make but often are the source of 'difficult to repair' leaks in the field. While more expensive, the operator would be better served by totally separate towers with an external equalizer pipe with individual isolation valves for each tower. Not only would the sumps be easily isolated to perform repairs but airflow would be fully isolated as well.
If a new tower is about to be purchased, seek out a knowledgeable sales engineer to insure items like equalizers are considered.
Expert Cooling Tower Repair, LLC