In the past month I have had a few customers that were quoted upgrades to their DE's (Drift Eliminators) and when asked why I
responded with the usual short answer of "several reasons". I listed one or two issues and we carried on about our day.
However, in looking back I don't feel that I answered the question as well as I could have. So I decided to answer it thoroughly
here for everyone to read.
There truly are "many reasons" to change out your DE's. We have addressed them all below, saving the most important ones
for last. There are a few other reasons that could be causing the drift problems besides failing DE's. One most recent finding
suggests that the addition of a surfactant in large doses a couple times a week could cause excessive drift. If there are any
further questions or you would like an analysis of your tower, feel free to contact us directly.
Excessive drift diminishes the service life of the fan stack and fan deck because of the amount of moisture they absorb from
the drift. In some cases where weep holes were not present in the stack ribs, the excess weight can actually collapse the fan
deck. Much of the fan deck and fan deck supports that we have replaced due to rot, were caused by excess drift.
Reducing the amount of drift from your tower increases the service life of your mechanical components. The drift acts as an
oxidizing agent on the gearbox and equipment supports causing them to rust more quickly. The drift physically destroys the
fan blades because the blades pass quickly through the air laden with drift.
Excessive drift is also a safety issue because the fan deck and other walking surfaces surrounding the tower are perpetually
wet making slipping a constant risk. This is the same for stairways and ladders especially. In those climates that get cold in
the winter, the problem will be magnified due to ice forming on those same surfaces.
The last two issues go hand in hand and are the most critical reason for upgrading your DE's. The amount of drift loss that a
tower has can be quite a lot. Many of the older towers that have original DE's may be getting drift loss around .01%. If you
can actual feel the water in the air on and around the tower, it may be as high as .02 - .03% drift loss. The newer DE's can
achieve results of .001% to as low as .0005% (See links below) . To put these numbers in prospective, let's assume that you
have a 10 cell tower with a capacity of 120,000 GPM. At a .03% drift loss, you would be losing 51,840 gallons for every day
that tower runs! Can anyone say water conservation?
The second half of this circulating water loss issue is the environmental impact of the chemicals and potential bacteria
released in the drift. Bacteria such as Legionella Pneumophila can be released into the air and cause major health concerns
for the surrounding population and employees. Now of course every cooling tower does not have Legionella and may have
very different treating programs based on a number of variables, but It cannot be ignored that excessive drift could have
adverse effects to the environment near that tower.
If you have a perpetually wet cooling tower, let us know and we would be happy to diagnose the issue and work you up an
estimated cost to upgrade your DE's if necessary. We know this is one upgrade that will pay for itself!
As always, let us know how you liked this article.
responded with the usual short answer of "several reasons". I listed one or two issues and we carried on about our day.
However, in looking back I don't feel that I answered the question as well as I could have. So I decided to answer it thoroughly
here for everyone to read.
There truly are "many reasons" to change out your DE's. We have addressed them all below, saving the most important ones
for last. There are a few other reasons that could be causing the drift problems besides failing DE's. One most recent finding
suggests that the addition of a surfactant in large doses a couple times a week could cause excessive drift. If there are any
further questions or you would like an analysis of your tower, feel free to contact us directly.
Excessive drift diminishes the service life of the fan stack and fan deck because of the amount of moisture they absorb from
the drift. In some cases where weep holes were not present in the stack ribs, the excess weight can actually collapse the fan
deck. Much of the fan deck and fan deck supports that we have replaced due to rot, were caused by excess drift.
Reducing the amount of drift from your tower increases the service life of your mechanical components. The drift acts as an
oxidizing agent on the gearbox and equipment supports causing them to rust more quickly. The drift physically destroys the
fan blades because the blades pass quickly through the air laden with drift.
Excessive drift is also a safety issue because the fan deck and other walking surfaces surrounding the tower are perpetually
wet making slipping a constant risk. This is the same for stairways and ladders especially. In those climates that get cold in
the winter, the problem will be magnified due to ice forming on those same surfaces.
The last two issues go hand in hand and are the most critical reason for upgrading your DE's. The amount of drift loss that a
tower has can be quite a lot. Many of the older towers that have original DE's may be getting drift loss around .01%. If you
can actual feel the water in the air on and around the tower, it may be as high as .02 - .03% drift loss. The newer DE's can
achieve results of .001% to as low as .0005% (See links below) . To put these numbers in prospective, let's assume that you
have a 10 cell tower with a capacity of 120,000 GPM. At a .03% drift loss, you would be losing 51,840 gallons for every day
that tower runs! Can anyone say water conservation?
The second half of this circulating water loss issue is the environmental impact of the chemicals and potential bacteria
released in the drift. Bacteria such as Legionella Pneumophila can be released into the air and cause major health concerns
for the surrounding population and employees. Now of course every cooling tower does not have Legionella and may have
very different treating programs based on a number of variables, but It cannot be ignored that excessive drift could have
adverse effects to the environment near that tower.
If you have a perpetually wet cooling tower, let us know and we would be happy to diagnose the issue and work you up an
estimated cost to upgrade your DE's if necessary. We know this is one upgrade that will pay for itself!
As always, let us know how you liked this article.
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