US4043901A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Wood chip screens
Assignee: Gauld Equipment Sales Co
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Filing: 1975-12-03
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Granted: 1977-08-23
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Expires: 1995-12-03
Abstract
Abstract A drum screen for cleaning and classifying wood chips is mounted for rotation. The screen has apertures of varying size to permit cleaned chips to pass through to be deposited on conveyors located below. An internal annular spiral baffle extends the full length of the drum and a series of chip lifters are located between the flights of the spiral baffle and project radially inwards from the interior surface of the drum. Wood chips are fed into the drum at one end and are carried through the drum while being lifted towards the axis of the drum by the chip lifters to effect loosening of waste material from the chips. Cleaned chips pass through the apertures in the drum and chips too large to pass through are carried forward and discharged from the end of the drum onto a conveyor. A casing surrounds the upper portion of the drum and partially encloses the discharge end of the drum. An air suction device is connected to the discharge end of the drum, drawing off all waste material loosened from the chips.
Inventors
- 👤 Warren Thomas Gauld
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:14
CPC Classifications
B; B07; B07B; B07B4/00; B07B4/02; B07B4/06; B07B1/00; B07B1/18; B07B1/22; B07B1/24
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
251 words
A wood chip screen of the rotary type comprising a screen having perforations in a first inlet portion thereof to permit passage therethrough of fines material and having perforations in a second discharge portion thereof to permit pasage therethrough of acceptable chips, a hollow spiral baffle secured to the inner surface of the screen, means to separate unwanted material from the wood chips and to float said unwanted material into the interior of the screen, air suction means creating an air stream to withdraw from the interior of the screen the said unwanted material, said air suction means including a conduit communicating with the interior of the screen at an end thereof such that the unwanted material can pass with said air stream directly from the interior of the screen into said conduit without passing through the screen perforations, and including a fan means for drawing air from the interior of the screen into said conduit, a cyclone separator in communication with the fan, first conveyor means below the said screen to receive the fines and acceptable chips, and second conveyor means adjacent the discharge end of the screen to receive oversize wood chips, and a casing enclosing the upper half and a portion only of the lower half of the screen in spaced relation thereto, the said casing including an end closure plate adjacent to the discharge end of the screen, said conduit connecting the said fan with the interior of the screen through the said casing and closure plate.
Claim 2
Dependent Claim
251 words
A wood chip screen of the rotary type comprising a screen having perforations in a first inlet portion thereof to permit passage therethrough of fines material and having perforations in a second discharge portion thereof to permit pasage therethrough of acceptable chips, a hollow spiral baffle secured to the inner surface of the screen, means to separate unwanted material from the wood chips and to float said unwanted material into the interior of the screen, air suction means creating an air stream to withdraw from the interior of the screen the said unwanted material, said air suction means including a conduit communicating with the interior of the screen at an end thereof such that the unwanted material can pass with said air stream directly from the interior of the screen into said conduit without passing through the screen perforations, and including a fan means for drawing air from the interior of the screen into said conduit, a cyclone separator in communication with the fan, first conveyor means below the said screen to receive the fines and acceptable chips, and second conveyor means adjacent the discharge end of the screen to receive oversize wood chips, and a casing enclosing the upper half and a portion only of the lower half of the screen in spaced relation thereto, the said casing including an end closure plate adjacent to the discharge end of the screen, said conduit connecting the said fan with the interior of the screen through the said casing and closure plate.
Claim 3
Dependent Claim
67 words
A wood chip screen as set forth in claim 1 in which the perforations in the inlet portion of the screen are smaller in size than the perforations in the discharge portion of the screen, and the said first mentioned conveyor means include a pair of conveyors, one located under the inlet portion of the screen and the other located under the discharge portion of the screen.
Claim 4
Dependent Claim
53 words
A wood chip screen as set forth in claim 1 in which the said second mentioned conveyor means comprises a spiral conveyor and a conduit extending between one end of the spiral conveyor and the adjacent end of the chip screen below the lower edge of the end plate of the said casing.
Claim 5
Dependent Claim
33 words
A wood chip screen as set forth in claim 1 in which the said conduit joins with the said casing end plate on the upper portion of the vertical axis of the screen.
Claim 6
Dependent Claim
46 words
A wood chip screen as set forth in claim 1 in which the means to separate the unwanted material from the wood chips include a series of longitudinally disposed chip lifters secured to the inner surface of the screen between the flights of the spiral baffle.
Claim 7
Dependent Claim
28 words
A wood chip screen as set forth in claim 5 in which the said chip lifters are equally spaced apart circumferentially about the inner surface of the screen.
Claim 8
Dependent Claim
43 words
A wood chip screen as set forth in claim 5 in which the said chip lifters are flat plates extending radially inwards from the periphery of the screen to a depth equal to the radial depth of the end flanges of the screen.
Claim 9
Dependent Claim
58 words
A wood chip screen as set forth in claim 1 in which the screen has shallow end flanges extending radially inwards from the periphery of the screen, and the radial depth of the spiral baffle extends inwards from the periphery of the screen to a depth greater than the radial depth of the end flanges of the screen.
Claim 10
Dependent Claim
65 words
A wood chip screen as set forth in claim 8 in which the lower edge of the casing end closure plate is located at the lowest level of the inner peripheral edge of the spiral baffle to provide an oversize chip discharge opening between the lower edge of the end closure plate and the adjacent inner peripheral edge of the end flange of the screen.
Claim 11
Dependent Claim
30 words
A wood chip screen as set forth in claim 9 in which a conduit connects the said oversize chip discharge opening of the screen with the said second conveyor means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-08-22 | 1981-02-21 | 1981-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-22 | 1985-02-21 | 1985-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-22 | 1989-02-21 | 1989-08-23 | $7700.00 | Window Closed / Lapsed |