The dispute is about Cactus dryers

From Jim…A medical tubing producer in the N.E.


Question:


The dispute is about Cactus dryers. I will not use them because they only use ambient air passed over heaters. I have heard they do not work well unless it is only surface moisture. I cannot find any data that supports their drying claims. Am I currect in my assumption that they cannot dry ie PU weel enough or be consistent in an extrusion tubing process.

 

Answer:


The Cactus is typical of hot air dryers with the exception that it uses compressed air instead of blower power to move the air. Because of this, it will be slightly lower in dew point, at times, if your compressed air is very dry. However, it will not be more consistent than your plant Relative Humidity. This can be and issue, especially in the summer.

When drying PU, it is usually important to control both the temperature and resin moisture to get consistent product flexibility and strength.

There are other dryers that use compressed air and a membrane and develop very consistent processing of PU. The NovaDrier is a good example of these and it uses far less power and compressed air than any other of its kind. The dew point and temperature are consistent, year round.

 

Mark Haynie...Sales Manager – Dryer Products, Novatec, Inc.