Filtration and System Design

When a circuit design is in the planning stages it is much more than determining what the real purpose of the system is. Look at the application and think, how are we going to achieve our goal? What do we want this system to do?

You start selecting components, valves, hoses, piping, pump, motor, actuators, tanks, and other equipment. Include your initial cost of building the system, step back and look, and you may feel like you’ve really achieved something and reached the mountain top. There are a few other factors involved to consider, weight, ease of maintenance, operating cost, and machine duty cycle.

Doing it properly, there are actually four “major” activities involved in the design proc-ess:

1. Evaluate the specification.
2. Establish the proper components.
3. Select the circuit design.
4. Conduct performance analysis to make sure the design will perform the way you want it to.

There you have it. However, many times improper and inadequate filtration has been designed into the system, or not even designed in at all. Remember, if the filtration breaks down, the system will break down. From monitoring bulk fluids to filtering the fluids before they are introduced into the system, storage and handling is just as impor-tant as keeping contamination under control while it is passing throughout the system. Fluid conditioning must be monitored at all levels. Remember, up to 90% of all system failures are caused by contaminated fluids.

Where do you start? First, identify the most sensitive component in the system. Select the fluid that is right for that compo-nent. Select the appropriate filter element media that will get the job done after considering operating pressure, fluid com-patibility, level of filtration, operating temperature, media strength, and capacity. Then you have to determine where the filtration is going to be located. What about the type of housing? These are some of the areas to consider when designing proper filtration into the system.

There is yet another area in which it is necessary to keep the fluid clean. Let’s not forget the breathing in of air. Air contains contamination. The system breathes in and out as the reservoir fluid level rises and falls. Unless there is a breather that will filter out the contaminants, you are leaving yourself wide open for eventual system failure. Not only does one have to think about particle contamination in this area, but also moisture. Water is the second most destructive contamination to a system. Maybe a desiccant breather is warranted. Food for thought.

Controlling contamination is number one priority. When designing systems make sure cleanliness target levels are deter-mined and then take the steps needed to achieve those targets. However, you can’t stop there. It is imperative that these lev-els are measured frequently to insure your targets are met. Check ISO requirements to see if you are meeting their guidelines for fluid cleanliness levels.

So you see, whether you are merely straining to keep nuts, bolts, and other chunks out of your system, or your operation re-quires ultra filtration to protect the components, there is a lot of planning that has to take place. It takes more than a few hundred words in this format to answer all the questions when it comes to decisions to be made about proper filtration.

A great place to begin the educational process is the AFS Basic Short Courses. The Liquid Filtration Basic Short Course and the Gas/Air Filtration Basic Short Course, both are offered in conjunction with the annual and fall AFS conferences. Learn about filter media, equipment, filtration principles, particles, fluid properties, performance, testing, and standards. Invest in your future. There are no shortcuts. Follow the links below.

Author: Don Krause, Flow Ezy Filters, Inc.

Don Krauser is one of the instructors for the AFS Short Courses, Basic Liquid Filtration. It will be offered on Monday, May 19, 2008 at the Radisson Valley Forge, Valley Forge, PA.

To discover more about Liquid Filtration register for this short courses.

Attendees that are AFS members and attendees that attend the AFS Annual conference beginning on May 20th receive registration discounts on AFS short courses. If you are not currently a member you can become one in the registration process.

If you want to receive a short filtration lesson every month, sign up for the AFS e-newsletter.

© 2008 American Filtration & Separations Society All rights reserved