Clean cooling water towers are critical to ensuring an efficient plant. Using side stream filtration, a portion of the cooling water is continuously filtered and returned to the system to remove suspended solids from cooling tower systems. Side-stream filtration works on the principle that continuous particle removal will keep the system clean.
Nalco Pretreatment Solutions (PTS) manufactures the UltraSand Plus High Efficiency Filters (HEF) Side Stream Filtration Systems to remove suspended solids from open or closed recirculating cooling systems. The ability to remove extremely fine particles is the key to successful cooling water filtration. The unique design of the side stream filter provides 0.5 or 0.25 micron particle removal with minimal backwash water requirements. This particle filtration level is impossible to achieve with traditional multimedia depth filters or single media surface filters.  This helps minimize downtime, maintenance & cleaning costs while reducing the possibility of under-deposit corrosion and much more.
Cooling systems require large volumes of air to promote evaporative cooling. The majority of particles in air are between 0.5-2.0 microns, as are the majority of particles found in cooling water. This particulate in water systems is a proven contributor to fouling of critical heat exchange equipment.
A typical analysis reveals that over 99% of particles in cooling water are below 15 microns in size and over 97% of particles in cooling tower water fall between 0.5 and 2.0 microns. Therefore, the ability to remove these extremely fine particles is the key to successful cooling water filtration. Conventional multimedia depth filters are generally effective at removing tower water particles between 10-15 microns in size. However, particles smaller than this are typically responsible for deposition and other problems.
| Mean Particle Size in Air (microns) | Particle Count |
|---|---|
| >20 | 0.0% |
| 7.5 - 20 | 0.2% |
| 4.0 - 7.5 | 0.3% |
| 2.0 - 4.0 | 1.0% |
| 0.5 - 2.0 | 97.0% |
| <0.5 | 1.5% |
High Efficiency Filtration:
UltraSand PLUS high-efficiency filtration systems provide over 60% particle removal over the 0.5-1.0 micron range and 80% removal over the 1.0-5.0 micron range compared to traditional multimedia depth filters, which provide virtually no particle removal over the 0.5-5.0 micron range (when coagulants are not used).
Nalco PTS UltraSand PLUS high-efficiency filtration Systems feature stainless steel tanks, automated individual electric activated valve nest, electronic controller, and a range of options for almost any industrial application. Backwash is initiated by a timer or a differential pressure switch. Multiple units can be configured in parallel to accommodate flowrates up to 800 gallons per minute.
System Features:
UltraSand PLUS high-efficiency filtration systems are specifically designed to remove particulate deposition in cooling systems and avoid the negative fouling impact that heat transfer surfaces have on plant efficiency, throughput, and operating costs. These filters are available as a part of an integrated solution to improve your operation and lower your total cost of ownership:
When unfiltered water is directed horizontally into the filter tank, an area of turbulence is created over the bed. Particulate trapped on the surface by the ultra-fine sand is scrubbed off the surface by these turbulent forces. This scrubbing action keeps the filtration surface clean and available for continued particle removal. Watch the UltraSand Plus in action.
Nalco PTSÂ offers onsite preventive maintenance to monitor and maintain these units in peak performance and reduce the workload of your team.
