Most furniture factories have considerable bent stock which must of necessity be thoroughly steamed before bending. By steaming, the initial process of the Moist-air kiln has been consummated. Hence, the Blower kiln is better adapted to the drying of such stock than the Moist-air kiln would be, as the stock has been thoroughly soaked by the preliminary steaming, and all that is required is sufficient heat to volatilize the moisture, and a strong circulation of air to remove it as it comes to the surface.
The Moist-air kiln is better adapted to the drying of tight cooperage stock, while the Blower kiln is almost universally used throughout the slack cooperage industry for the drying of its products.
For the drying of heavy timbers, planks, blocks, carriage stock, etc., and for all species of hardwood thicker than one inch, the Moist-air kiln is undoubtedly the best.
Both types of kilns are equally well adapted to the drying of 1-inch green Norway and white pine, elm, hemlock, and such woods as are used in the manufacture of flooring, ceiling, siding, shingles, hoops, tub and pail stock, etc.
The selection of one or the other for such work is largely matter of personal opinion.
Kilns of Different Types
All dry kilns as in use to-day are divided as to method of drying into two classes:
- The "Pipe" or "Moist-air" kiln;
- The "Blower" or "Hot Blast" kiln;
both of which have been fully explained in a previous article.
The above two classes are again subdivided into five different types of dry kilns as follows: