A Closer Look at Vapor Degreasing Technology
Process Cleaning, Sofia Modesto
For those that have been in the Navy or know about how the Navy does things, they are well aware of how ships are maintained. The engine and mechanical rooms of most all Navy ships are immaculate. The expression “you could eat off the floor” is quite appropriate because these areas are so well maintained.
This top-notch maintenance goes far beyond just the appearance of the rooms. The ship engines as well as all of the ship’s mechanical equipment are kept clean as a whistle, in top running order. Keeping these areas spotless improves professionalism, morale and ensures that the ships are always running properly.
Similarly, manufacturing and production facilities must keep their factory equipment in top running order at all times. Here as well, clean and well maintained assembly line equipment and mechanicals offers the same attributes it does the Navy: professionalism, worker morale and helps guarantee that the products produced are in top running order.
One way manufacturing facilities do this is by incorporating vapor degreasing systems. In most cases, a solvent is used with the systems, which are used in a variety of industries, from electronics and communications product’s assembly lines to the aircraft industry. In some cases, the steam or vapor produced by the system, without the addition of solvents or chemicals, is adequate enough to clean parts and mechanicals.
There are several reasons why vapor is so effective and its use is found in so many manufacturing facilities:
• Oils, grease and other soils are removed effectively and economically
• The cleaning process is fast, requiring a minimal amount of labor
• Many vapor degreasing machines are small, requiring very little factory floor space
• Equipment cleaned with a vapor degreasing system drives very quickly, reducing downtime
• Often, the solvents used can be recovered and recycled
Effect on the EnvironmentAlthough the solvents are effective cleaners, helping to dissolve the grease and oil that forms on production line mechanicals and parts, some of these solvents are not environmentally healthy. For instance, chemicals such as 1,1,1-trichloroethylene, a synthetic chemical that does not occur naturally in the environment, is being phased out because it is potentially harmful to the cleaning workers and, once it enters the atmosphere, to the ozone layer.
The U.S. Environmental Protection Agency lists alternatives to 1,1,1-trichloroethylene, however, many of these are also considered hazardous pollutants. Although new solvents are under development, some manufacturing facilities have had success cleaning mechanicals with no chemicals and just steam vapor. Some lightweight, portable machines are available that heat water to more than 245ºF. This is hot enough to dissolve many soils and, because it is chemical free, completely safe for the cleaning worker to use and for the environment.
However, if a solvent is necessary, selecting one can be very complex and depend on a number of factors. In this case, factory managers should turn to their distributors marketing the products, or the manufacturers themselves, for consultation before making a purchasing decision. In addition, because the rules and regulations on the use of these products are continually being evaluated, they should check state and federal policies in regards to these solvents as well.
How it WorksVapor degreasing technology is simple. A heat source raises the liquid solvent (or water) to the boiling point. When the solvent boils, it produces very hot, heavy vapors, which are then cooled by condenser coils, to monitor the heat. Because the solvent vapors are heavier than air, they push the air above the vapor line on to the parts and equipment to be cleaned. Condensation takes place, which dissolves the greases and oils on the parts and flushes them away.
If only water is used and no chemical, the same process occurs. But in this case, heat places a very important role in this cleaning process because it is the heat of the steam/vapor that dissolves soils.
In some situations, neither system adequately cleans heavy soil build-up on production line mechanicals. In this case, heated spray degreasers are brought in to dissolve soils. Similar to vapor degreasers, they have a solvent pump, filter canister and spray wand. Mechanicals must be sprayed with care so that the solvents do not become airborne.
Increasing EfficiencyOne of the many reasons vapor degreasing technology is so popular is because it is effective using a fraction of the energy of most other cleaning processes. However, performing the process properly and employing the right equipment is necessary to minimize solvent loss, which can affect the cost of the cleaning process. For the most part, solvent is lost as a result of four main causes:
1. Dragout—During the cleaning process, some solvent remains liquefied. Additional heat is required to vaporize and remove the liquid solvent from parts and mechanicals. This could not be prevented in the past but newer equipment technology can reduce or eliminate this problem.
2. Air movement—Even a small amount of air movement, from open windows, doors, HVAC systems and fans, have a significant affect on increasing solvent loses and slowing down the cleaning process. It was not realized until recently just how small an amount of air movement can affect solvent loss. It is now believed that if any air movement is detected, it is too much.
3. Diffusion—Diffusion occurs when two gasses mix with each other in the cleaning process. It is similar to air movement—the solvent is deflected on to surfaces not needing to be cleaned. Though a minor cause of solvent loss, it is greater with low boiling solvents.
4. Convection—Convection is air movement caused when the vapor comes in contact with equipment surfaces. This most often occurs when using high boiling solvents.
Factory managers are encouraged to evaluate the many factors presented here and the uses of vapor degreasing technology to determine if it is the cleaning process best for their facilities. Proper training is a mandatory requirement for its use. But vapor degreasing technology is effective and when used with environmentally friendly solvents or with no chemicals at all, it may increasingly become factory mechanics cleaning process of choice to protect the environment.
Sofia A. Modesto is engineering manager with Tornado Industries (Chicago, IL), makers of a full line of professional cleaning equipment for a variety of facilities. She can be reached at (708) 867-5100.