Labconco Paramoun Ductless Enclosures 69636 Series, 6' Widths User Manual

Page 73

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The following examples are useful for estimating filter life so the Filter Life
Timers can be set properly.

Organic Vapor Carbon Filter Life
Consult the separate Paramount Chemical Guide and/or Labconco Specialist
to determine the filter capacity for your chemical. For example, assume you
are working with 10 ppm acetone in a 3' Paramount loaded with the required
four filters. Acetone has a specific gravity SPGR = 0.79 with a molecular
weight MW = 58.1. A 3' Paramount at 80 fpm uses 175 CFM or 4956 LPM.
The evaporation rate in ml/min can be solved by the following equation:
PPM = (SPGR/MW) * (24400000/Airflow (LPM)) * Evap. Rate (ml/min).

For 10 ppm acetone or 90 ml lost per week during 2 hours use per day, the
equations are solved below:

10 = (0.79/58.1) * (24400000/4956) * Evap. Rate (ml/min)

Evap. Rate = 0.15 ml/min = 90 ml/week * 1 week /10 hours use *

10 hours/600 minutes

Evap. Rate in (g/min) = 0.15 ml/min * 0.79 g/ml = 0.12 g/min


There are 30 pounds of activated carbon in a 3' Paramount which equals
13,500 g. Thus, the carbon Filter Life Time is calculated for acetone with a
2% filter capacity at (13,500 g/0.12 g/min) / (1 hour/60 min) * 2% capacity =
38 hours. The Final Life Timer should be set for 40 hours, rounded up from
38 hours. The Check Life Timer should be set for 20-25% intervals or every
10 hours and the carbon filters can be validated every 10 hours to verify safe
filter use.

Other chemicals such as ethyl acetate at 9% filter capacity and toluene at
20% filter capacity have much longer filter lives. For example, ethyl acetate
at 10 ppm used in the 3' Paramount will have a Filter Life of 120 hours.
Furthermore, toluene at 10 ppm used in the 3' Paramount will have a Filter
Life of 240 hours. These three chemicals are summarized in the table that
follows to show the Filter Life ranges and you should consult the Labconco
Specialist and/or Paramount Chemical Guide for further information on other
chemicals.

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