CONTROL THE FLOW TO YOUR PRESSURE FILTERS AND YOU WILL CONTROL THE COSTS OF YOUR MEDIA

Flat bed, roll media pressure filters are selected for a given application at a specified flow rate so it can accomplish the cleaning function with an acceptable level of media usage. The flow through the filter is know as filter flow or filter flux and is measured in gallons per minute per square foot (liters per minute per square meter).

Once a system is started, the flows through the pressure filters are adjusted to meet the design flow rates. Control of the flow is important so it does not exceed the GPM per square foot rating because there is a correlation between flow rate and media consumption and performance. If the flow is higher than the designed rate the filter will use more media.

Many installations have allowed the filter flow through pressure filters to increase beyond the designated rate because:

1. More machines were put on the line without adding capacity of the filtration system.
2. Flow is increased because more flushing is perceived to be needed.
3. Valves are randomly opened without understanding actual flow design criteria.

The first item may show some justification since it may be less expensive to use more media than it is to revamp the total system for the added machines; assuming fluid clarity levels are acceptable. However, items 2 and 3 usually result in wasting money on media and sacrificing performance. The cost the extra media could be significant because the correlation between flow and media usage (when all other conditions are the same) is not linear. For example;

• Flow rate increase of 25 percent- media usage goes up 70 percent.
• Flow rate increase of 50 percent- media usage goes up 260 percent.
• Flow rate increase of 75 percent- media usage goes up 400 percent.

Harrigan Solutions understands this phenomenon and can offer advice on how to mitigate the problem. They offer engineering help on how to control the flow or how to improve your filtration system if enhancement is needed. They sell or rent new and used pressure filters depending upon the customers economical goals. They also have service programs where technicians can monitor the operation, perform routine maintenance, and train personnel for customers who do not have the staff to cover this area. For more information contact Bill Harrigan at 1-888-685-9603.
Email at bharrigan@harrigansolutions.com.
The website is www.harrigansolutions.com/index.htm