We have a film laminator that has an 8"dia. x 24" roller that is heated with oil and has some passages or baffling inside. The oil is heated and pumped through the roller providing a large thermal mass. After years of using the wrong oil and overheating we have plugged the roller, not completly but to the point that we have cold spots and that makes the operators want to turn the heat up. compounding the problem The roller is sealed and cannot be taken apart for cleaning.
Is there a chemical process that could be to dissolve the hard crusty burnt oil in the cylinder ?
A single answer is not possible because there are many types of heat transfer fluids. Three types that I know of are glycols-water mixtures and glycols, hydrocarbon oils, silicon fluids.
Please give more deatils about the fluid used.
Another avenue for gettina answer is open to you if what was used was sold specifically as a heat transfer fluid. The manufacturers may have information on how to clean the system up. One example of this is the web site for Therminol® Information Bulletin No. 1 – Cleaning Organic Heat Transfer Fluid Systems, http://therminol.com/pages/tools/info1.asp.