Steaming Before Kiln-Drying: Good Idea?
Steaming wood before the drying cycle may or may not be wise. But in any case, the idea is patented. June 13, 2014
Question
Does anyone know what usually distinguish USA kilns form European kilns? This includes sensors, building way, control system, materials, schedules and etc.
Forum Responses
(Commercial Kiln Drying Forum)
From contributor L:
Not much difference. USA kilns tend to use less moisture probe controls. Europeans often spray water or steam at the beginning of the cycle, which is frowned on here but the structures are not much different.
From Gene Wengert, forum technical advisor:
The idea of using steam spray prior to drying has been patented recently in the USA. Hence, steaming, except for walnut and similar steaming, will require permission from the patent holder in the USA. I have seen many foreign (outside the USA and Canada) kilns that use hot oil rather than steam. I have also seen foreign kilns that prefer steaming for conditioning in a separate chamber rather than in the kiln.
From contributor F:
I have not seen the details of the patent for steaming before drying but it has been suggested to be done for many years and has been done. A patent is only good if the idea is novel and new. Therefore this patent sounds like it can easily be voided. It just takes someone that will to challenge it - if there is nothing new in the details.
From contributor K:
The little bit that I have dealt with kiln companies from Europe I sensed that they are much more concerned about energy consumption used during drying. Not that USA kilns don't care about energy consumption, but it seemed that European kilns tried to recover or make the most of any energy used. If I am not mistaken, electricity is much more expensive in Europe than in the USA. Maybe this is just a false assumption as well.
From Gene Wengert, forum technical advisor:
Unfortunately, it requires no less than $500,000 to challenge a patent in court. Even then, you may not win as juries are not fully. I was on the side of the party that did indeed challenge this patent and they did achieve a partial victory for themselves, but the patent remains in force. You can always use the patent without paying, but if you are sued, you will have to spend at least $300,000 defending yourself, etc. So, forget the idea that this has been disclosed before. The US Patent Office says that it is novel and you need to prove otherwise clearly and completely.
From the original questioner:
I'm very curious about it: can anyone give me the owner name or patent number? Anyway, seeing money wasted in that way is very sad. I think the patent office should protect good ideas and not thieves of old good ideas still used. In Europe, by my knowledge, is hard to protect a patent if there are proof that the idea (or the invention) was previous published (used). Is it maybe a difference from Europe to USA? I'm not an expert.
From contributor F:
All that money is spent only if the patent holder actually sues. Often the patent holder backs off and don't even pursue it. If you talk to a patent lawyer they will tell you it is not worth trying to defend a patent.
From contributor D:
Modern vacuum kilns give you the fastest drying time with the lowest drying cost and the least degrade with any thickness or species that requires a month or more in a conventional kiln.
From contributor L:
I don't think the conditioning step at the beginning of the process would be covered by the Elder patent unless the steps were the same as covered in the patent and the way the use the first step of conditioning in European kilns is different. I do think what they do in Europe is a bad idea and you can damage a lot of lumber if you do it with air dried stock. There is one case both Gene and I are aware of where about 200,000 BF of oak was ruined because the material was exposed to very high humidity at the beginning of the process. It is very risky and the idea that it opens the pores is a little sketchy in my opinion.
