By Chad Edmondson
Bad things happen when sediment collects in the bottom of a cooling tower cold water basin. Really bad. Things like premature equipment failure and downtime, not to mention fairly rapid loss of efficiency. That’s why JMP always recommends including factory installed sweeper piping on every new cooling tower. Out of all of the decisions you will face when designing a cooling tower, this one is a slam dunk.
An open cooling tower is a magnet for airborne dirt and debris. Whatever happens to be floating in the air around the cooling tower can and will end up in the cold-water basin. A typical 200 Ton cooling tower operating 1000 hours can accumulate up to 600 lb of particulate matter from airborne dirt and the makeup waters supply. Chemical treatment will not help sediment accumulation. In fact, sediment actually prevents the chemicals from coming in contact with the basin surface, so it actually undermines this costly treatment.
What Is Sweeper Piping?
A sweeper system installed in the bottom of the cooling tower uses pressurized streams of water to prevent the build-up of sediment. The pressurized water is introduced into the basin via a series of spray nozzles and piping connected to a manifold, all of which can (and should) be factory installed. The water sprays water horizontally across the bottom of the basin, pushing dirt away from the cooling tower cold water outlet, ideally towards the suction point for piping that leads to a filtration system where it can be permanently removed from the condenser water system. This filtration system is typically a centrifugal sediment separator but disc filters and sand filters can also be used.
Factory Installed Vs. Field Installed
Why does JMP advocate having the piping factory installed? Very simply it is more expensive and more difficult to install in the field. When a system is factory installed you can be certain the system is installed correctly. The piping can then be connected to whatever filtration system you choose for your application.
A factory-installed sweeper system sets the stage for long-term, worry-free cooling tower operation and affords owners the following benefits:
Reduces under-deposit corrosion, which extends the life of the basin, as well as condenser water piping
Minimizes manual cleaning, maintenance and downtime on cooling tower and helps protect downstream equipment
Maintains overall cooling tower efficiency by keeping heat transfer surfaces free from dirt and corrosion
Reduces opportunities for biological growth by removing food sources from the cooling tower
Reduces operational costs
Improves the effectiveness of other water treatment programs and reduces the amount of chemicals that are required