US3660225A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Delignification and bleaching of cellulose pulp layers with oxygen gas
Assignee: Air Liquide SA
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Filing: 1969-07-10
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Granted: 1972-05-02
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Expires: 1989-07-10
Abstract
Abstract A method of dividing a stream of pulp into a series of layers comprising discrete batches and progressively transferring the batches from layer to layer in controlled fashion so that the height of each layer does not exceed a maximum value at which the pulp at the bottom of a layer has a predetermined minimum gaseous content, the pulp being contacted with oxygen gas under pressure while progressively transferring pulp from one layer to the next in the series. The method may occur in an apparatus comprising a cylindrical pressure vessel including axially spaced floors which define chambers between them, the chambers being subdivided into a plurality of compartments by dividing walls disposed axially to the pressure vessel and transversely to the floors, each floor having an aperture and the compartments and floors being relatively movable to allow pulp in the compartments sequentially to be transferred from one chamber to the next as relative movement occurs.
Inventors
- 👤 Abraham Jacob Verreyne
- 👤 Leonard Austin Job
- 👤 Paul Rerolle
- 👤 Johan C F C Richter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:17
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/10; B; B01; B01F; B01F27/00; B01F27/80; B01F27/93; B01F35/00; B01F35/50; B01F35/53; B01F35/531; B01F35/5312; D21C9/1026; B01F27/05; B01F27/11; B01F27/19; B01F27/191
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
18 words
A method as claimed in claim 1, wherein the pulp is fluffed prior to being distributed in layers.
Claim 2
Dependent Claim
35 words
A method as claimed in claim 1, wherein the pulp is transferred from one layer to the next in the series and away from the last layer in the series under the influence of gravity.
Claim 3
Dependent Claim
33 words
A method as claimed in claim 1, wherein pulp is transferred sequentially in stepwise fashion from one layer to the next in the series and away from the last layer in the series.
Claim 4
Dependent Claim
52 words
A method as claimed in claim 1, wherein the pulp in each layer is subdivided into a plurality of discrete batches which are transferred sequentially in stepwise fashion from one layer to the next in the series and away from the last layer in the series substantially without intermixing with other batches.
Claim 5
Dependent Claim
96 words
A method as claimed in claim 5, wherein the support for each layer of pulp is removed sequentially from underneath successive batches of pulp in the layer to permit the sequential transfer of successive batches of pulp from one layer to the next under the influence of gravity, the transfer of pulp from one layer to the next being controlled for a batch of pulp transferred from one layer to the next to occupy free space in said next layer which has previously been vacated by a batch of pulp transferred away from said next layer.
Claim 6
Dependent Claim
88 words
A method as claimed in claim 1, wherein the pulp in each layer is collected in a plurality of separate compartments as discrete batches which are transferred sequentially in stepwise fashion from one layer to the next in the series and away from the last layer in the series substantially without intermixing with other batches, new batches of pulp being collected sequentially in successive compartments in the first layer in the series to replace batches which are transferred from the first to the second layer in the series.
Claim 7
Dependent Claim
29 words
A method as claimed in claim 1, wherein the height of each layer with the possible exception of the first layer in the series does not exceed 3.00 meters.
Claim 8
Dependent Claim
29 words
A method as claimed in claim 7, wherein the height of each layer with the possible exception of the first layer in the series does not exceed 1.20 meters.
Claim 9
Dependent Claim
275 words
A continuous method of treating a cellulose pulp with oxygen gas under pressure comprising the steps of continuously introducing pulp at a consistency of 16 to 67 percent into the upper region of a vertically elongated pressure vessel; breaking up the pulp into well divided form; heating the pulp; distributing the heated and well divided pulp in a series of separate layers which are individually supported within the presSure vessel at different levels along the length of the pressure vessel, each layer of pulp comprising a plurality of discrete batches sequentially removing the support for each layer from underneath successive batches of pulp in the layer to permit the sequential transfer in stepwise fashion of successive batches of pulp from one layer to the next in the series and away from the last layer in the series under the influence of gravity substantially without intermixing with other batches; controlling the transfer of pulp from one layer to the next to permit a batch of pulp transferred from one layer to the next to occupy free space in the next layer which has previously been vacated by a batch of pulp transferred from said next layer; restricting the height of each layer of pulp with the possible exception of the first layer in the series not to exceed 3.00 meters; contacting the pulp in each layer with oxygen gas at a partial pressure in excess of 3 bars absolute; re-uniting in the lower region of the pressure vessel batches of pulp which have been transferred away from the last layer in the series; and continuously withdrawing treated pulp from the lower region of the pressure vessel.
Claim 10
Dependent Claim
155 words
A continuous method of treating cellulose pulp with oxygen gas under pressure comprising the steps of continuously introducing pulp at a consistency of 16 to 67 percent into the upper region of a vertically elongated pressure vessel; breaking up the pulp into well divided form; heating the pulp; distributing the heated and well divided pulp in a series of separate layers individually supported within the pressure vessel at different levels between the top and the bottom of the vessel; progressively transferring pulp downwardly in stepwise fashion under the action of gravity from one layer to the next in series; restricting the height of each layer of pulp with the possible exception of the first layer in the series not to exceed 3.00 meters; contacting the pulp in each layer with oxygen gas at a partial pressure in excess of 3 bars absolute; and continuously withdrawing treated pulp from the lower region of the pressure vessel.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-02 | 1975-11-01 | 1976-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-02 | 1979-11-01 | 1980-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-02 | 1983-11-01 | 1984-05-02 | $7700.00 | Window Closed / Lapsed |