Why not start with what the Poly Products Evaporator is and how it got here.
The most popular piece of equipment sold at Poly Products Inc. is the ET-III-W™ evaporator. The ET are the initials for simply Evaporative Tank, the III stands for the third design (it’s a roman numeral 3, not one, one, one), and the legendary W stands for Waste water. The W today is a bit of a misnomer; we use the ET-III-W™ evaporator as the evaporator of choice for waste water applications as well as solution recovery / concentration applications.
The ET-II™ evaporator was the first production based Poly Products evaporator. It replaced what was basically a hand made welded prototype evaporator in the early 1980’s. The ET-II™ evaporator was constructed of a one piece roto-molded virgin Polyethylene tub, yellow Blower Sleeve, and blue pyramid Vent Transition. These are the three components that make-up the main assembly of the evaporator. Unlike the ET-III-W™ evaporator, the ET-II™ evaporator relied on a packing inside the yellow blower sleeve to create surface area for the evaporation to occur. The ET-II™ evaporator had 700 square feet of surface area from finned evaporative panels stacked neatly on the grid in the bottom of the Blower Sleeve.
The ET-III™ evaporator had 1,000 square feet of surface area packed inside of the yellow blower sleeve. The ET-III™ evaporator was just a larger version of the ET-II™ evaporator. They have the same dimensions from the side, but the ET-III™ evaporator is wider.
Both the ET-II™ evaporator and the ET-III™ evaporator were used on plating rinse water solutions so that the rinse water can be reconcentrated and reused as valuable plating solution. (Future articles will talk about this technique and how it has become the norm in modern plating shops all across America and around the world).
As the popularity of the evaporator grew, so did the creativity of the applications. It made sense that evaporation could help the smaller waste water generator reduce his waste water hauling costs. “Why pay to haul water?”. The evaporator was used to reduce the waste water volumes for countless industries, but in the first attempts, we found that the tight packing had small and easy to clog passage ways. The packing worked just fine in a plating line application, with a chemistry lab monitoring and filtering the bath, but when the evaporator was used on an application that was literally waste water, and we would evaporator to the point of saturation, the evaporator would clog.
The ET-III-W™ evaporator has the same external appearance as the ET-III™ evaporator; the difference is within.
The packing was removed. There are no finned evaporative panels inside the ET-III-W™ evaporator. The small spray nozzles were removed and replaced with specially made large high flow nozzles. These nozzles have a ½ inch cross section at the smallest point. These large, wide-open passage ways are well suited to pass the solids that are typically in a Waste Water application.
The water spray forms many, many droplets inside the evaporator, where the packing formally resided. These many droplets create a tremendous amount of surface area. So much area, that the evaporation rate is actually better in the waste water evaporator, the ET-III-W™, than it was in the ET-III™ evaporator. Further, without the cost of the old fashion “packing” the ET-III-W™ evaporator also cost less money.