US3875680A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for producing wet stiff corrugated board
Assignee: Forestry Research Institute of Sweden
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Filing: 1973-04-11
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Granted: 1975-04-08
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Expires: 1993-04-11
Abstract
Abstract Corrugated board is made wet stiff by blowing hot air through the flutes thereof and subsequently blowing cooling and remoistening air therethrough. During the treatment the corrugated board is stationarily placed in a chamber sealed at all sides, the chamber being connected with a recirculating channel provided with circulation blower, heat batteries, air exchange valves, vapour and hot water nozzles and means for controlling the circulation air.
Inventors
- 👤 Ernst Ludvig Back
- 👤 Rolf Gote Anderson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 00:42
CPC Classifications
F; F26; F26B; F26B21/00; F26B21/30; F26B21/20; F26B21/25; F26B25/00; F26B25/06; F26B9/00; F26B9/06
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
99 words
A device for obtaining wet stiffness of corrugated board, comprising chamber means for receiving at least one stack of corrugated board, the flat surfaces of said board being substantially horizontal, means for sealing the top, bottom and sides of said at least one stack, such that all air is forced to pass through the flutes of the corrugated board, the flutes of the corrugated board being connected in both ends with recirculation channel means, said recirculation channel means including a circulation blower, heat batteries, air exchange valves, vapour and hot water nozzles and means for controlling the circulation air.
Claim 2
Independent Claim
99 words
A device for obtaining wet stiffness of corrugated board, comprising chamber means for receiving at least one stack of corrugated board, the flat surfaces of said board being substantially horizontal, means for sealing the top, bottom and sides of said at least one stack, such that all air is forced to pass through the flutes of the corrugated board, the flutes of the corrugated board being connected in both ends with recirculation channel means, said recirculation channel means including a circulation blower, heat batteries, air exchange valves, vapour and hot water nozzles and means for controlling the circulation air.
Claim 3
Dependent Claim
37 words
The device of claim 1, wherein said sealing means are vertically adjustable so as to press against the top of said stack, and laterally movable to adapt said chamber to different sizes of said corrugated board stack.
Claim 4
Dependent Claim
24 words
The device of claim 1, wherein the recirculation channel means has the capacity to provide air heated to a temperature between 170.degree. and 250.degree.C.
Claim 5
Dependent Claim
23 words
The device of claim 3, wherein there is a capacity to keep the heated air at a velocity between 3 and 15 m/s.
Claim 6
Dependent Claim
29 words
The device of claim 1, wherein the recirculation channel means has the capacity to pre-moisten air sufficient that the stack attains a moisture content of 5 - 12 percent.
Claim 7
Dependent Claim
37 words
The device of claim 1, wherein at least one of the components of the corrugated board in said stack is provided with at least one metal salt having a metal ion with high redox potential added thereto.
Claim 8
Dependent Claim
27 words
The device of claim 1, wherein at least one of the components of the corrugated board in said stack is provided with a thermosetting resin added thereto.
Claim 9
Independent Claim
205 words
A device for obtaining wet stiffness of corrugated board, comprising chamber means for receiving at least one stack of corrugated board formed from linear and corrugated medium components being free from thermosetting additives and bonded together by sizing with an adhesive selected from the class consisting of synthetic adhesives and starches and mixtures thereof, the planes of said stack being substantially horizontal, means for sealing the top, bottom and sides of said at least one stack such that all air is forced through the flutes of the corrugated board, the flutes of the corrugated board being connected in both ends with a recirculation channel, which is provided with circulation blower, heat batteries, air exchange valves, vapour and hot water nozzles and means for controlling air which circulates within said device together having the capacity to blow air pre-heated to a temperature in the range of 185.degree.-210.degree.C with a velocity in the range of 3-15 m/s through the flutes of said corrugated board and subsequently blowing cooling air of a lower temperature and finally blowing pre-moistened air of less than 90.degree.C having at least 60 percent relative humidity through said stack to provide a moisture content in said corrugated board in the range of 7-10 percent.
Claim 10
Independent Claim
205 words
A device for obtaining wet stiffness of corrugated board, comprising chamber means for receiving at least one stack of corrugated board formed from linear and corrugated medium components being free from thermosetting additives and bonded together by sizing with an adhesive selected from the class consisting of synthetic adhesives and starches and mixtures thereof, the planes of said stack being substantially horizontal, means for sealing the top, bottom and sides of said at least one stack such that all air is forced through the flutes of the corrugated board, the flutes of the corrugated board being connected in both ends with a recirculation channel, which is provided with circulation blower, heat batteries, air exchange valves, vapour and hot water nozzles and means for controlling air which circulates within said device together having the capacity to blow air pre-heated to a temperature in the range of 185.degree.-210.degree.C with a velocity in the range of 3-15 m/s through the flutes of said corrugated board and subsequently blowing cooling air of a lower temperature and finally blowing pre-moistened air of less than 90.degree.C having at least 60 percent relative humidity through said stack to provide a moisture content in said corrugated board in the range of 7-10 percent.
Claim 11
Dependent Claim
61 words
The device of claim 1, wherein the chamber is provided with vertically and laterally adjustable sealings, said lateral sealings consisting of the walls of the treatment chamber of which one wall by means of hydraulic cylinders can be pushed along grooves or guides, and said vertically adjustable sealing means being adaptive through hydraulic means to the width of the treatment chamber.
Claim 12
Dependent Claim
31 words
The device of claim 9, wherein the lateral sealings further comprise sealing baffles oblique to the direction of the air flow which are pressed against the stack by the air flow.
References Cited (Backward Citations)
US1677963A
Cited
US2064965A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |