In the winter of 2006, CRMP experienced a series of failures of pneumatic equipment, which in turn led to costly plant downtime, says the company’s maintenance supervisor, Wayne Piland. Also, Piland reports that on cold days air line freeze-ups caused downtime and poor plant efficiency.

Piland contacted Van Air Systems and its Richmond-based distributor, PBE, Inc. After surveying the air system of a CRMP plant in Chesapeake, VA, Van Air and PBE determined that the pre-mature equipment failures and freeze-ups were being caused by excessive oil and water contamination in compressed air lines.

The concentration of water vapor in air lines is an inevitable outcome of the compression process. When air is discharged from the compressor, it is hot and in most cases 100% saturated with water vapor. As the air travels through system piping, it cools and water vapor turns to liquid. Additionally, lubricated compressors introduce oil into the compressed air lines. These contaminants often accelerate the wear of air system equipment, including piping, seals, valves, cylinders, actuators and air tools.

Van Air and PBE recommended that CRMP install an F200 series filter with a general purpose coalescing element, in conjunction with a single tower deliquescent Freedom Dryer, model D12.

A coalescing filter is often installed prior to a compressed air dryer and serves to remove liquid droplets and aerosols (both oil and water). The general purpose coalescing filter element that Van Air recommended reduces oil contamination to approximately .78 parts per million.

While Van Air Systems manufactures a wide range of compressed air dryer-types, single tower deliquescent dryers are uniquely suited to many ready mix plant applications. The air lines of many ready mix plants are outdoors and, in northern climates, exposed to sub-freezing ambient temperatures. Unlike refrigerated dryers, single tower deliquescent dryers, when properly applied, will prevent freezes-ups. Refrigerated dryers should not be installed outdoors where freezing temperatures are possible.  Further, single tower dryers have no moving parts, except for the drain, and tolerate dirty and dusty environments, like those found at concrete plants.   

As the name implies, a single tower dryer consists of one vessel. This vessel is filled with a bed of absorbent desiccant tablets. As wet compressed air flows through the tablets, water vapor is absorbed from the air. The tablets slowly dissolve (or deliquesce), and the resulting solution is manually or automatically drained from the vessel.

CRMP decided to install the recommended filter and dryer at the Chesapeake plant, along with Van Air automatic drain valves. Immediately, the oil carry-over problem was eliminated. And no subsequent freeze-ups have occurred. With clean and dry compressed air, Wayne Piland says that air system maintenance costs have been significantly reduced. CRMP has since installed Van Air filtering and drying systems at its other plants.