What happen to the pallet in HT?

Question: What happens to a pallet when it is heat treated.


Short answer:

We have seen very little and often no drying defects on standards pallets. We are not trying to dry the pallets during the heat treatment process. During a few studies we have seen about a 3-7% moisture loss per HT cycle, which is insignificant on green pallets. On drier recycled pallets we see a little more degrade and a water mist system might help prevent some of these drying defects, although our current customer that heat treat recycled pallets do not have a problem.

It is important to understand that one of the greatest threats to pallets that has been heat treated is Mold. So the drying climate of a direct heat sourse help reduce this chance, or maybe even drying the pallet make sense for your customer.


Detailed answer:

Study on the effects of heat treating a load of pallets. Before and after pictures plus weight loss.

During a heat treatment process we are not trying to dry the pallet and the vents stay closed throughout the heat treatment period. During the heat treatment cycle a little drying will occur, normally about 3-7%. You will probably find that a pallet will dry more on a flat bed truck during transport than during the heat treatment process.

On recycled pallets, which at generally much drier, you do not have the same moisture available in the pallet and a few more defects are likely. Since customers of recycled pallets generally are not looking for the same visible quality as customers of new pallets, this do not seem to be a problem. If you or your customer find that you would like to reduce the drying defects a high pressure spray system can be installed to help bring up the relative humidity faster.

A direct gas heating system will create a little drier climate than an indirect heat systems, such as hot water coils, steam coils, or tube based indirect gas heating. Indirect heating systems tend to use 15-25% more energy than direct gas heating systems (Learn more about the difference.).