Process for accelerated drying of green wood

A process for accelerating the drying of green wood comprising the following steps:

• sawing wood from a tree containing a moisture content;
• heating the wood with a heating fluid in an enclosure to a predetermined temperature at least about 120.degree. F. for a predetermined period of time sufficient to provide a generally uniform heating across the entire cross section of the wood and to maintain substantially the moisture content of the wood during heating;
• then exposing the heated wood to a cooling environment containing cooling fluid surrounding said wood of a temperature at least 30.degree. F. less than the temperature of said heated wood and a relative humidity of at least 10% less than the relative humidity of the heated enclosure for the transfer of internal heat and moisture to said cooling fluid;
• maintaining the exposure of said wood to said cooling fluid surrounding said wood for a period of time sufficient for the entire cross section of the wood to reach substantially the temperature of the surrounding cooling fluid with substantial moisture being removed from said wood;
• then reheating said wood in an enclosure to a predetermined temperature for drying of the wood;
• applying moisture within said enclosure to maintain a sufficient moisture content in the outer surface of said wood for minimizing any defects;
• and
• maintaining the reheating of said wood for a predetermined time period sufficient to reduce the moisture content of the wood to a predetermined target amount, the wet bulb depression in said enclosure increasing during said reheating of said wood.

A process for accelerating the drying of green wood comprising the following steps:

• a. sawing wood from a tree containing a moisture content;
• b. heating the wood with steam in a heating enclosure to a predetermined temperature at least about 120.degree. F. for a predetermined period of time sufficient to provide a generally uniform heating across the entire cross section of the wood and to maintain the moisture content of the wood during heating;
• c. then exposing said wood to a cooling environment containing cooling fluid surrounding said wood of a temperature at least 30.degree. F. less than the temperature of said heated wood and a relative humidity of at least 10% less than the relative humidity of the heating enclosure for the transfer of internal heat and moisture to said cooling fluid;
• d. maintaining the exposure of said wood to said cooling fluid surrounding said wood for a period of time sufficient for the entire cross section of the wood to reach substantially the temperature of the surrounding cooling fluid with substantial moisture being removed from said wood;
• and
• e. then repeating steps b, c and d in sequence for at least one time to reduce further the moisture content of the wood.

A method for pre-treating green wood to increase the permeability of the wood and to condition the wood for further drying in a kiln;

• said method comprising:
• sawing wood from a tree containing a moisture content that has been reduced a minimum amount from the original moisture content of the tree and is at least about 50%;
• heating the wood with steam in a heating enclosure to a predetermined temperature at least about 120.degree. F. for a predetermined period of time sufficient to provide a generally uniform heating across the entire cross section of the wood and to maintain the moisture content of the wood during heating;
• then exposing said wood to a cooling environment containing cooling fluid surrounding said wood of a temperature at least 30.degree. F. less than the temperature of said heated wood and a relative humidity less than the relative humidity of the heating enclosure for the transfer of internal heat and moisture to said cooling fluid;
• maintaining the exposure of said wood to said cooling fluid surrounding said wood for a period of time sufficient for the entire cross section of the wood to reach substantially the temperature of the surrounding cooling fluid with substantial of moisture being removed from said wood thereby completing the pre-treatment phase;
• and
• then transferring the pre-treating green wood to a kiln for completing the drying of said green wood.

A method for conditioning green wood to increase the permeability of the wood for further drying;

• said method comprising
• sawing wood from a tree containing a moisture content that has been reduced less than 10% from the original moisture content of the tree and is at least about 50%;
• heating the wood with steam in a heating enclosure to a predetermined temperature at least about 120.degree. F. for a predetermined amount of time sufficient to provide a generally uniform heating across the entire cross section of the wood and to maintain the moisture content of the wood during heating;
• then exposing said wood to a cooling environment containing cooling fluid surrounding said wood of a temperature at least 30.degree. F. less than the temperature of said heated wood and a relative humidity at least 10% less than the relative humidity of the heating enclosure for the transfer of internal heat and moisture to said cooling fluid;
• and
• maintaining the exposure of said wood to said cooling fluid surrounding said wood for a period of time sufficient for the entire cross section of the wood to reach substantially the temperature of the surrounding cooling fluid with at least 5% of moisture normally being removed from said wood thereby to condition said green wood for further drying.

A method for drying railroad cross ties comprising the following steps:

• sawing the cross ties from a tree containing a moisture content;
• heating the cross ties with steam in a heating enclosure to a predetermined temperature at least about 130.degree. F. for a predetermined amount of time sufficient to provide a generally uniform heating across the entire cross section of the cross ties and to maintain substantially the moisture content of the cross ties during heating;
• then exposing said cross ties to cooling fluid surrounding said cross ties of a temperature at least 30.degree. F. less than the temperature of said heated cross ties and a relative humidity of at least 10% less than the relative humidity of the heating enclosure for the transfer of internal heat and moisture to said cooling fluid;
• maintaining the exposure of said cross ties to said cooling fluid surrounding said cross ties for a period of time sufficient for the entire cross section of the cross ties to reach substantially the temperature of the surrounding cooling fluid with at least about 5% of moisture normally being removed from said cross ties;
• and
• then reheating said cross ties to a low temperature less than about 150.degree. F.

A process of conditioning wood comprising the following steps:

• applying a controlled heating fluid at a temperature between about 120.degree. F. and 190.degree. F. to the wood in a confined zone for a predetermined period of time sufficient to provide a generally uniform heating of the wood, the heating fluid having predetermined moisture content sufficient to maintain substantially the moisture content of wood;
• applying a cooling fluid after heating of the wood for substantially surrounding the wood, the cooling fluid having a temperature and humidity substantially less than the temperature and moisture content of the heated wood;
• and
• maintaining the application of the cooling fluid to the wood for a predetermined time period.