How to Maintain Heat Transfer Rolls, part 2

Heat Transfer Rolls & Effects of Temperature As we learned in How to Maintain Heat Transfer Rolls, Part 1 the primary goal in designing heat transfer rolls is to transfer heat from the web to the roll or from the roll to the web. Part 1 also defined the importance of using proper fluids, periodic cleaning, and flushing of your heat transfer rolls.  In Part 2, we will define best practices for storing your heat transfer rolls and the importance of remembering rust inhibitors. Heat Transfer Rolls – Storage Guidelines Precautions should always be taken when a heat transfer roll is put into storage as there is a high risk of internal and external corrosion.  There are a few key-points to consider while storing a heat transfer roll: Corrosion develops when a heat transfer roll is stored with fluid inside it and vented to the open air. Determining whether all fluid is removed from a heat transfer roll and the inside is dry is very difficult. High-humidity environments can still lead to corrosion. When moisture settles and corrosion develops, it will affect the heat transfer and roll balance. Acid cleaning after storage may or may not be able to remove corrosion and scale Coating the heat transfer roll with rust-preventative oil and a rust-preventative wrap will help to safeguard the exterior surfaces. Protective films such as VCI (vapor corrosion inhibitor) can be used in place of oil coatings. Remember the Rust Inhibitors Heat transfer rolls are usually manufactured using carbon steel, thus acid solutions will not damage its internal parts or surfaces. Effective flushing agents for heat transfer rolls...

Heat Transfer Rolls Maintenance, part 1

Heat Transfer Rolls & Effects of Temperature There is one primary goal when it comes to the design of heat transfer rolls: to transfer heat from the web to the roll or from the roll to the web. Utilizing concepts within the first law of thermodynamics where heat transfer occurs through a temperature difference, heat transfer rolls play an important part in various applications within the web converting process. There are many different designs of heat transfer rolls, one design of heat transfer rolls are manufactured with a dual shell construction: special inner flow chambers and (sometimes) special finishes. As a result, the procurement of heat transfer rolls often requires a significant investment and proper maintenance becomes essential. Periodic maintenance is required to maintain effective heat transfer performance over the life span of the heat transfer roll.  To lessen the risk of diminished heat transfer performance and reduce the likelihood of roll repair or replacement, C.R.E.W. recommends the following tactics: Use of proper fluids Periodic cleaning & flushing Remember the rust inhibitors Follow best practices for storage Use of Proper Fluids If the heat transfer roll uses thermal oil, it is best to follow the oil manufacturer’s guidelines. Water solutions have proven to be detrimental to a heat transfer rolls performance as suspended solids, water pH, and organics can eventually coat or clog its interior fluid channels. The water may even cause rust on the rolls inner surfaces. For best results using water, it is highly recommended to run a 25-50% mixture of ethylene glycol with rust inhibitors to clean water. Periodic Cleaning & Flushing If your heat transfer...