One area where dry ice blasting excels is in cleaning electric motors, and it’s especially effective on very large and expensive motors that are mounted in areas where access and the surroundings are challenging.
First, the basics of dry ice need a review. I’ve written a more detailed blog post titled “Dry Ice Blasting – How Does It Work” so review that if you want a little more detail. Here’s the basics.
Dry ice is frozen carbon dioxide gas, which at around -109 degrees Fahrenheit turns into a solid form, dry ice. We use dry ice as a blast media into a specialized machine and propel the ice at surfaces using compressed air.
It is important to note that dry ice has no abrasive qualities, it will not etch or profile metallic surfaces, although ice can affect porous surfaces such as concrete, wood or plaster.
IMPACT, TEMPERATURE AND SUBLIMATION provide the cleaning muscle of dry ice blasting, the Impact of the ice hitting the surface removes some contaminates, the change in Temperature caused by the extreme cold of the dry ice helps relieve surface tension of contaminants, and the energy of the dry ice converting back to a gas upon impact, releasing energy in a volume expansion that creates an explosive effect called Sublimation, that is a force multiplier, getting underneath loose debris and generally increasing the already potent cleaning power of just the impact itself.
For a power plant, steel mill or sewage treatment plant, large electric motors become dirty through the process of the operation or simply through ordinary accumulation over time. Outdoor environments increase the accumulation, as to dirty environments of a water treatment/sewage facility, or the dust generated by a mill or other manufacturing operation.
This dirt, dust and debris accumulates on the motors and has at least two effects that are not good for the motor, the first is a degradation of the ability for the motors housing to dissipate the heat generated by the motors operation. A clean steel housing is much more efficient than one that is dirty, and the more dirt the less efficient. Inefficient heat dispersal can degrade the life of the motor significantly, and require replacement more often.
Secondly, the ability to inspect, work on and maintain the motor is affected when the motor is contaminated with foreign substances. Electricians and maintenance crews are not a cheap labor source and having them have to spend a great deal of time cleaning the motor before working on it can be expensive. In the even the motor is down, that time can be quite valuable.
Our experience has shown that once your motors have been cleaned the first time, the cost of annual maintenance is more economical due to the speed increase of maintenance cleaning versus a long deep cleaning of a motor necessary if it’s not routinely kept clean. The frequency of cleaning is highly dependent on the nature and time it takes for the motor to require cleaning coupled with the expense of a motor going down on the ongoing operations.
One good thing about dry ice blasting, except in rare cases, the motor does not require being disconnected from the power supply, and in some cases we can clean the motor while it’s operating, although we prefer to have the power to unit off out of an abundance of caution. Throw that together with only having to capture the debris coming off the motor, since there’s no media dust, and it can become a fast and cost effective solution.