Seven Rules for Improving the Quality of Compressed Air

Follow these tips to increase productivity and profits in your plant.

In today's global economy, much has been written on how important it is for U.S. manufacturers to improve productivity and increase profits. The compressed air system remains an excellent source for such increased efficiencies.

Like gas, electricity, and water, compressed air is a common utility in most industrial and process plants. Typically, pneumatics consumes 10% to 15% of a plant's electrical energy. The difference is that while other utilities are purchased, compressed air must be generated in-house. This puts the burden on the user to ensure the air is suitable for plant operations.

At times, this can lead to neglect, which in turn leads to decreased efficiency and increased costs. Here are seven simple ways to improve this important fourth utility.

Rule # 1— Keep compressor intake filters clean
Compressor intake filters are gravely neglected. Clean up the area around them and put a barrier up to protect dirt from entering the area around them. Install throw-away panel filters (50 µm) and change them frequently. Provide easy access to these filters and keep a regular log on filter change. This will save energy by having the compressor run more efficiently.

Rule # 2 — Monitor aftercoolers
Install and monitor the proper gauges. Temperature gauges for inlet cooling water should be installed on the aftercooler along with outlet compressed air temperature gauges. The discharge compressed air temperature should be no higher than 20° F above the inlet water temperature.

Rule # 3 — Find the right location for air dryers and compressor room filtration
Location can affect how well an air dryer performs. The site for the air-cooled refrigerated air dryer should be well ventilated so heat can be carried away. Keep the condenser on the refrigeration dryer free of dirt and make sure the drain is reliable. This will help maintain the proper dew point and keep the plant air dry.

In regards to the pre- and postair filters in the dryer circuit, the elements should be replaced at least once per year or as needed, and the drains cleaned and monitored. This will prevent costly pressure drop that needlessly robs the system. Such drain failure can be catastrophic.

Rule # 4 — Specify the right in-plant compressed air filters
Standard compressed air filters are currently available in range of cleanliness from 5 to 50 µm. Most would agree that cleaner air is desired (5 µm), assuming no other significant differences or penalties in flow, pressure drop, frequency of service, and price. Cleaner air is possible, and filters are available from various manufacturers that meet the above criteria. Get more involved when buying and specifying filters — and the benefit will be better machine performance and productivity.

Rule # 5 — Monitor pressure with regulators
Just as under-pressurization of components is costly, so is over-pressurization. It is both dangerous and a major waste of compressed air. A simple solution is to install a tamper-resistant kit on each regulator. After the secondary pressure is set, no unauthorized personnel can easily tamper with changing pressures. This offers major energy savings and is a good safety practice.

Rule # 6 — Maintain air line lubricators
A lubricator meters oil into the compressed air system to lubricate downstream system components and actuators. Make sure this component remains filled with a lightweight lubricating oil and do not over-lubricate components. Most manufactures offer an automatic fill port, which makes it easier to fill under pressure. Assign someone to fill these weekly, and the wear from rust and corrosion will be greatly improved.

Rule # 7 — Get proper training — the key to making it happen
Getting control of the compressed air system is going to make it possible for any plant that relies on air to improve the quality of the product they manufacture and to improve their productivity. A number of key personnel within the plant must understand this complex utility and make a committed effort to upgrade and monitor the improvements. Education about the cost and complexity of this system is imperative.

An easy way to learn is to attend local seminars or lunch-and-learns held by your local pneumatic fluid power distributors or compressor distributors. They have extensive knowledge on this subject, and should be used as a valuable source. Or simply attend educational events like the Fluid Power Conference & Expo, being coordinated by the H&P staff in Tampa, Fla., May 16-17 and Cleveland, November 13-14.

Most of these recommendations can be done on a modest budget, where the real cost is in not doing anything.

For more information, contact Bob Gleason at (215) 480-3676 or e-mail [email protected]