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US3680219A Expired / Lapsed US ⏱️ 0.0 years remaining

Process for steam straightening and kiln drying lumber

Assignee: United States Department of Agriculture
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Filing: 1970-09-22
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Granted: 1972-08-01
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Expires: 1990-09-22
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Abstract

Abstract A process for steam straightening and kiln drying lumber, the lumber being held under total restraint with respect to warping during the process. The lumber is steam straightened and kiln dried to a moisture content of nine percent using a cross-circulation air velocity of 1000 f.p.m. at dry and wet bulb temperatures of 240* F and 160* F for a first interval followed by a second interval at 195* F and 185* F. The lumber is cooled prior to being released from restraint.

Inventors

  • 👤 Peter Koch

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 07:10
CPC Classifications
F; F26; F26B; F26B7/00; F26B21/00; F26B21/30; F26B2210/00; F26B2210/16

Claims Analysis

Total Claims: 2
Claim 1
Independent Claim 184 words
An improved process for kiln drying and steam straightening sized permeable lumber comprising the following sequential steps: a. forming to size individual pieces of lumber. b. securing the sized pieces of lumber within a rigid racking means which racking means is adapted to impose upon the sized pieces of lumber total restraint against warping in both the width and the thickness dimensions, c. kiln drying and steam straightening the sized pieces of lumber at a dry-bulb temperature of at least about 240* F. and employing an air circulation velocity of at least about 1,000 feet per minute to attain an average moisture content of ten percent, d. steaming the said pieces of lumber from step (c) still under restraint in the racking means for at least about three hours at the highest possible dry-bulb temperature at which a ten degree wet-bulb depression can be maintained with continued air circulation at about 1,000 feet per minute, e. cooling the said pieces of lumber from step (d) while still under restraint, and f. removing the finished, kiln-dried, steam straightened pieces of lumber from the racking means.
Claim 2
Dependent Claim 184 words
An improved process for kiln drying and steam straightening sized permeable lumber comprising the following sequential steps: a. forming to size individual pieces of lumber. b. securing the sized pieces of lumber within a rigid racking means which racking means is adapted to impose upon the sized pieces of lumber total restraint against warping in both the width and the thickness dimensions, c. kiln drying and steam straightening the sized pieces of lumber at a dry-bulb temperature of at least about 240* F. and employing an air circulation velocity of at least about 1,000 feet per minute to attain an average moisture content of ten percent, d. steaming the said pieces of lumber from step (c) still under restraint in the racking means for at least about three hours at the highest possible dry-bulb temperature at which a ten degree wet-bulb depression can be maintained with continued air circulation at about 1,000 feet per minute, e. cooling the said pieces of lumber from step (d) while still under restraint, and f. removing the finished, kiln-dried, steam straightened pieces of lumber from the racking means.

References Cited (Backward Citations)

US15316A Cited
US217022A Cited
US528496A Cited
US1054597A Cited
US1212583A Cited
US1276979A Cited
US1328662A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1975-08-01 1976-01-31 1976-08-01 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1979-08-01 1980-01-31 1980-08-01 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1983-08-01 1984-01-31 1984-08-01 $7700.00 Window Closed / Lapsed

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