US1951017A - Method of treating chemical pulf - Google Patents
Method of treating chemical pulf Download PDFInfo
- Publication number
- US1951017A US1951017A US681251A US68125133A US1951017A US 1951017 A US1951017 A US 1951017A US 681251 A US681251 A US 681251A US 68125133 A US68125133 A US 68125133A US 1951017 A US1951017 A US 1951017A
- Authority
- US
- United States
- Prior art keywords
- pulp
- fibres
- medullary ray
- fibers
- longitudinal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 title description 21
- 239000000126 substance Substances 0.000 title description 11
- 239000000835 fiber Substances 0.000 description 31
- 238000004061 bleaching Methods 0.000 description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- 230000002596 correlated effect Effects 0.000 description 8
- 239000002023 wood Substances 0.000 description 8
- 229920001131 Pulp (paper) Polymers 0.000 description 6
- 238000010411 cooking Methods 0.000 description 5
- 229920005610 lignin Polymers 0.000 description 4
- 238000000926 separation method Methods 0.000 description 4
- 239000007844 bleaching agent Substances 0.000 description 3
- 238000004040 coloring Methods 0.000 description 3
- 230000000704 physical effect Effects 0.000 description 3
- 239000007921 spray Substances 0.000 description 3
- 239000000470 constituent Substances 0.000 description 2
- 239000004744 fabric Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- RZVAJINKPMORJF-UHFFFAOYSA-N Acetaminophen Chemical compound CC(=O)NC1=CC=C(O)C=C1 RZVAJINKPMORJF-UHFFFAOYSA-N 0.000 description 1
- 229920000298 Cellophane Polymers 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229920000297 Rayon Polymers 0.000 description 1
- 238000010009 beating Methods 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 239000013043 chemical agent Substances 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 150000004677 hydrates Chemical class 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
Images
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
- D21D5/00—Purification of the pulp suspension by mechanical means; Apparatus therefor
- D21D5/02—Straining or screening the pulp
- D21D5/04—Flat screens
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/01—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with flat filtering elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/50—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with multiple filtering elements, characterised by their mutual disposition
- B01D29/52—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with multiple filtering elements, characterised by their mutual disposition in parallel connection
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/62—Regenerating the filter material in the filter
- B01D29/64—Regenerating the filter material in the filter by scrapers, brushes, nozzles, or the like, acting on the cake side of the filtering element
- B01D29/6438—Regenerating the filter material in the filter by scrapers, brushes, nozzles, or the like, acting on the cake side of the filtering element nozzles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/76—Handling the filter cake in the filter for purposes other than for regenerating
- B01D29/78—Handling the filter cake in the filter for purposes other than for regenerating for washing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/88—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices
- B01D29/94—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices for discharging the filter cake, e.g. chutes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/88—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices
- B01D29/94—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices for discharging the filter cake, e.g. chutes
- B01D29/945—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor having feed or discharge devices for discharging the filter cake, e.g. chutes for continuously discharging concentrated liquid
Definitions
- This invention relates to the preparation of chemical paper pulp and particularly to an improved method of treating pulp to facilitate bleaching thereof and a product of enhanced whiteness and better physical properties.
- Chemical paper pulp is produced by cooking Wood chips in various chemical solutions.
- the present invention can be applied to pulps produced by any of the well known processes. It is particularly applicable to pulps produced from coniferous woods, but it may be utilized in treating pulp from any source.
- the fibres or cells which make up the original wood structure may be divided roughly'into two classes, longitudinal fibres and medullary ray fibres.
- the longitudinal fibres are those which are arranged substantially parallel to the vertical axis of the tree and which make up the main cellulosic component of the wood.
- the medullary ray fibres are short fibres which in the original wood are substantially perpendicular to the axis of the tree. They serve as binders for the longitudinal fibres and .as conductors of sap from the inner bark to the longitudinal fibres.
- the bulk of the non-cellulosic wood substance generally referred to as lignin is dissolved out and the remaining chemical wood pulp is made up of a more or less pure fibre mixture consisting of longitudinal fibres and medullary ray fibres.
- the proportion of these two constituents is roughly 90-92% by weight of longitudinal or long fibres, and 840% by weight of medullary ray fibres.
- the longitudinal fibres vary in length, depending upon the wood species, from about 2.8 millimeters to about 4.5 millimeters.
- the medullary ray fibres are readily distinguishable because they are much shorter than the longitudinal fibres, being about 1/25 to 1/30 of the length thereof, and having about the diameter of the longitudinal fibres.
- the medullary ray fibres are much morere-r sistant to the action of the cooking liquor than,
- Another object of the invention is to provide a method of removing the medullary ray fibres from the longitudinal fibres before the pulp is bleached, whereby coloring elements are separated from the pulp and bleaching is accomplished'more readily and with a lower consumption of bleaching agents.
- pulp may be produced by any of the well known chemical processes. After the completion of the cooking, the pulp is washed to removethe chemical cooking agent and is screened to remove knots and shieves or unresolved wood particles in the usual manner.
- the pulp as thus prepared consists of longitudinal fibres and the short medullary ray fibres, and is then subjected to the procedure hereinafter described to separate the medullary ray fibres from the longitudinal fibres.
- the pulp is first diluted to a consistency of approximately .2% to 3% by weight with water, and it is then caused toflow over a suitable separating medium, for example, a screen of wire cloth having about 25 meshes to an inch.
- a suitable separating medium for example, a screen of wire cloth having about 25 meshes to an inch.
- the large excess of ater carries the short 10o medullary ray fibres thrcugh'the screen and effectively separates them.
- From 90 to 95% of the short medullary ray fibres may be removed thus from the pulp, leaving the longitudinal fibres which may be delivered to, a suitable conveyor the short medullary ray fibres from the pulp.
- Water may be sprayed uponthe pulp as it passes over the separating screen, although dilution of the pulp as indicated is usually sufiicient to ac- 5 complish the desired purpose.
- the separation of the medullary ray fibres from the pulp removes a considerable proportion of coloring elements from the original pulp. This is shown readily by the improved whiteness of the pulp from which the medullary ray fibres have been removed, and also by the color of the medullary ray fibres which have been separated.
- the medullary ray fibres may be collected from the water in which they are suspended and formed into sheets. Such sheets show a distinctly darker tone than the original pulp, whereas sheets formed from the longitudinal fibres display a distinctly lighter tone than the original pulp.
- the fractionated pulp may be subjected to any .of the .usual bleaching operations.
- the details of such operations are well known and form no part of the present invention.
- the bleached pulp .can. be brought to a high degree of "whiteness closely approximating a complete absence of color, without reducing the strength and other desirable qualities of the product.
- the longitudinal fibres from.' which the medullary ray .5 fibres have been separated may be bleached with a smaller proportion of bleaching agent, and particularly need not be subjected to'the more drastic treatment necessary to removecoloring elements from the medullary ray fibres.
- the deterioration of the longitudinal fibres through excessive bleaching necessary to secure'a white product is thus avoided by the expedient of removing medullary ray fibres before the bleaching operation.
- the reduced 'cost of bleaching and I6 the resulting improvement in the product compensate for a loss of upward to 10% of the original pulp, even where the short medullary ray fibres are discarded.
- the short medullary ray fibres may be bleached after separation by any of the well known bleaching processes. It is possible to utilize the short medullary ray fibres after separation for the production of paper stock, or for mixing with various pulps to secure the desired results, such as a quick-beating pulp, since the fine material hydrates much more readily than the longer fibres.
- the short medullary ray fibres may be used also as a raw material for"the preparation of alpha cellulose and in the viscose and cellophane industries.
- 5 indicates a trough from which the pulp, previously diluted to approximately .2% to .3%, is permitted to overflow onto.
- screens 6 which are disposed at a suitable angle, for example about 45. The angle of inclination'is not important except that it must be sufiicient to permit the pulpto fiow freely but not too rapidly.
- the screens may consist of wire mesh cloth having about 25 meshes per inch. In the practical apparatus, the screens may be about 8 feet from the trough 5 to trough 7 in which the pulp is collected and from which it may be withdrawn by screw conveyors 8.
- Pipes 9 may be provided to spray water onto the screens 6, particularly near the lower ends thereof;
- the water which dilutes the pulp and any additional spray water passes through the screens 6 carrying with it the short medullary ray fibres, so that the pulp which accumulates in the trough '7 consists substantially of longitudinal fibres only.
- the water with the short medullary ray fibres is collected in a receptacle 10 beneath the screens and may be withdrawn through a pipe 11 and delivered to suitable settling or separating tanks 12.
- pipes 13 may be provided to spray water 1 into the trough 7 which may be perforated to Iii) permit the escape of the water with any residual pass therethrough, while the longer longitudinal fibers pass thereover.
- the method of treating unbleached cellulosic pulp which comprises separating the medullary ray, or other fibres of similar length from the longer longitudinal fibres of the pulp by the method which consists in flowing the pulp downwardly-over an inclined screen, the inclination of the screen and the mesh thereof being so correlated that the medullary ray, and other fibers of similar length, will pass therethrough, while the longer longitudinal fibers will pass 15c thereover, and thereafter bleaching the pulp consisting of substantially only the longer longitudinal fibers.
- the method of improving cellulosic pulp for bleaching which comprises removing the medullary ray, or other fibers of similar length, and colloidal matter from the longer longitudinal fibers by the method which consists in flowing pulp downwardly over an inclined screen, the inclination of the-screen and the mesh thereof being so correlated that the medullary ray, and other short fibers, and the colloidal matter will pass therethrough, while the longer longitudinal fibers will pass thereover.
- the method of improving cellulosic pulp for bleaching which comprises removing the medullary ray, or other fibers of similar length, and
- the mesh thereof being so correlated that the medullary ray, and other short fibers, and the colloidal matter will pass therethrough, while the longer longitudinal fibers will pass thereover.
- the method of treating cellulosic pulp which comprises separating the medullary ray, or other fibres of similar length from the longer longitudinal fibres of the pulp by the method which consists in flowing unbleached pulp downwardly over an inclined screen, the inclination of the screen and the mesh thereof being so correlated that the medullary ray, and other fibers of similar length, and colloidal matter will pass therethrough, while the longer longitudinal fibers will pass thereover, and thereafter bleaching the pulp consisting of substantially only the longer longitudinal fibers.
- the method of treating cellulosic pulp which comprises separating the medullary ray, or other fibres of similar length from the longer longitudinal fibres of the ..pulp by the method which consists in flowing unbleached pulp, having a consistency of approximately 0.2 to 0.3 percent, downwardly over an inclined screen, the inclination of the screen and the mesh thereof being so correlated that the medullary ray, and other fibers of similar length, and colloidal matter will pass therethrough, while the longer 1ongitudinal fibers will pass thereover, and thereafter bleaching the pulp consisting of substantially only the longer longitudinal fibers.
Description
March 13, 1934.
R. s. HATCH 1,951,017
METHOD OF TREATING CHEMICAL PULP Filed July 20, 1933 VENTOR' ATTORN EYS Patented Mar. 13, 1934 UNITED STATES PATENT OFFICE METHOD OF TREATING CHEMICAL PULP Application July 20, 1933, Serial No. 681,251
9 Claims.
This invention relates to the preparation of chemical paper pulp and particularly to an improved method of treating pulp to facilitate bleaching thereof and a product of enhanced whiteness and better physical properties.
Chemical paper pulp is produced by cooking Wood chips in various chemical solutions. The present invention can be applied to pulps produced by any of the well known processes. It is particularly applicable to pulps produced from coniferous woods, but it may be utilized in treating pulp from any source.
The fibres or cells which make up the original wood structure may be divided roughly'into two classes, longitudinal fibres and medullary ray fibres. The longitudinal fibres are those which are arranged substantially parallel to the vertical axis of the tree and which make up the main cellulosic component of the wood. The medullary ray fibres are short fibres which in the original wood are substantially perpendicular to the axis of the tree. They serve as binders for the longitudinal fibres and .as conductors of sap from the inner bark to the longitudinal fibres.
When the wood substance is resolved by chemical agents, the bulk of the non-cellulosic wood substance, generally referred to as lignin is dissolved out and the remaining chemical wood pulp is made up of a more or less pure fibre mixture consisting of longitudinal fibres and medullary ray fibres. The proportion of these two constituents is roughly 90-92% by weight of longitudinal or long fibres, and 840% by weight of medullary ray fibres. the longitudinal fibres vary in length, depending upon the wood species, from about 2.8 millimeters to about 4.5 millimeters. The medullary ray fibres are readily distinguishable because they are much shorter than the longitudinal fibres, being about 1/25 to 1/30 of the length thereof, and having about the diameter of the longitudinal fibres. v
The medullary ray fibres are much morere-r sistant to the action of the cooking liquor than,
are the longitudinal fibres. It is much more difficult to remove the non-cellulosic material from the medullary ray fibres. Whether thisis due to the manner in which the lignin or non-cellulosic constituents are combined withthe Il'lfid', ullary ray fibre substance is not known. I have discovered, howeven-that after cooking the med- "ullary ray fibres contain a larger proportion of non-cellulosic constituentsand particularly coloring elements than the longitudinal fibres. In
In coniferous woods,-
order to bleach the medullary ray fibres it is necessary to subject them to a much more dras tic bleaching treatment than is required to whiten the longitudinal fibres. If, therefore, the pulp is bleached to a suitable whiteness, the lonat; gitudinal fibres are considerably weakened and the physical properties of the pulp are deterio-= rated.
It is the object of the present invention to provide a method of treating chemical paper as pulp so as to facilitate the bleaching operation and to produce a brighter pulp having improved physical properties.
Another object of the invention is to provide a method of removing the medullary ray fibres from the longitudinal fibres before the pulp is bleached, whereby coloring elements are separated from the pulp and bleaching is accomplished'more readily and with a lower consumption of bleaching agents.
Other objects and advantages of the invention will be apparent as it is better understood by reference to the following specification and accompanying drawing, in which the figure represents diagrammatically an apparatus adapted for 30 use in separating the medullary ray fibres from the unbleached chemical paper pulp.
In carrying out the invention, pulp may be produced by any of the well known chemical processes. After the completion of the cooking, the pulp is washed to removethe chemical cooking agent and is screened to remove knots and shieves or unresolved wood particles in the usual manner. The pulp as thus prepared consists of longitudinal fibres and the short medullary ray fibres, and is then subjected to the procedure hereinafter described to separate the medullary ray fibres from the longitudinal fibres.
In carrying out the invention, the pulp is first diluted to a consistency of approximately .2% to 3% by weight with water, and it is then caused toflow over a suitable separating medium, for example, a screen of wire cloth having about 25 meshes to an inch. In thus flowing over the screen, the large excess of ater carries the short 10o medullary ray fibres thrcugh'the screen and effectively separates them. From 90 to 95% of the short medullary ray fibres may be removed thus from the pulp, leaving the longitudinal fibres which may be delivered to, a suitable conveyor the short medullary ray fibres from the pulp.
Water may be sprayed uponthe pulp as it passes over the separating screen, although dilution of the pulp as indicated is usually sufiicient to ac- 5 complish the desired purpose.
The separation of the medullary ray fibres from the pulp removes a considerable proportion of coloring elements from the original pulp. This is shown readily by the improved whiteness of the pulp from which the medullary ray fibres have been removed, and also by the color of the medullary ray fibres which have been separated. The medullary ray fibres may be collected from the water in which they are suspended and formed into sheets. Such sheets show a distinctly darker tone than the original pulp, whereas sheets formed from the longitudinal fibres display a distinctly lighter tone than the original pulp.
The improvement can be demonstrated, moreover, by definite tests indicating bleachability and lignin content. As an example, a pulp subjected to the test for bleachability with chlorine gave the following results: 26 Per cent (0) Original pulp -1 5.54 (b) Longitudinal fibres 5.12 (c) Medullary ray fibres 7.8
o This pulp, when tested for lignin content, gave the following results:
' Per cent (41) Original pulp 2.54 (b) Medullary ray fibres 5.10
Uniractlonated Fractionated 0 Mullen. 108 113 Teen-.. 2. 2. Fold 1 72 Alpha per cent 88. 36 89. 41 Copper No 2. 20 2. 08 0 It will be observed that in the fractionated pulp every characteristic of the product has been improved as the result of,the separation of the short medullary ray fibres.
The fractionated pulp may be subjected to any .of the .usual bleaching operations. The details of such operations are well known and form no part of the present invention. The bleached pulp .can. be brought to a high degree of "whiteness closely approximating a complete absence of color, without reducing the strength and other desirable qualities of the product.
It is evident from the foregoing tests that the longitudinal fibres from.',which the medullary ray .5 fibres have been separated may be bleached with a smaller proportion of bleaching agent, and particularly need not be subjected to'the more drastic treatment necessary to removecoloring elements from the medullary ray fibres. The deterioration of the longitudinal fibres through excessive bleaching necessary to secure'a white product is thus avoided by the expedient of removing medullary ray fibres before the bleaching operation. The reduced 'cost of bleaching and I6 the resulting improvement in the product compensate for a loss of upward to 10% of the original pulp, even where the short medullary ray fibres are discarded.
The short medullary ray fibres may be bleached after separation by any of the well known bleaching processes. It is possible to utilize the short medullary ray fibres after separation for the production of paper stock, or for mixing with various pulps to secure the desired results, such as a quick-beating pulp, since the fine material hydrates much more readily than the longer fibres. The short medullary ray fibres may be used also as a raw material for"the preparation of alpha cellulose and in the viscose and cellophane industries.
As anexample of a suitable apparatus for the practice of the invention, 5 indicates a trough from which the pulp, previously diluted to approximately .2% to .3%, is permitted to overflow onto. screens 6 which are disposed at a suitable angle, for example about 45. The angle of inclination'is not important except that it must be sufiicient to permit the pulpto fiow freely but not too rapidly. The screens may consist of wire mesh cloth having about 25 meshes per inch. In the practical apparatus, the screens may be about 8 feet from the trough 5 to trough 7 in which the pulp is collected and from which it may be withdrawn by screw conveyors 8. Pipes 9 may be provided to spray water onto the screens 6, particularly near the lower ends thereof; The water which dilutes the pulp and any additional spray water passes through the screens 6 carrying with it the short medullary ray fibres, so that the pulp which accumulates in the trough '7 consists substantially of longitudinal fibres only. The water with the short medullary ray fibres is collected in a receptacle 10 beneath the screens and may be withdrawn through a pipe 11 and delivered to suitable settling or separating tanks 12. If desired, pipes 13 may be provided to spray water 1 into the trough 7 which may be perforated to Iii) permit the escape of the water with any residual pass therethrough, while the longer longitudinal fibers pass thereover.
2. The method of treating cellulosic pulp to separate the medullary ray or other fibers of similar length, from the longer longitudinal fibers, which" consistinfiowing the pulp, having a consistency of approximately 0.2 to 0.3 percent, downwardly over an inclined screen, the inclination of the screen and the mesh thereof being so correlated that the medullary ray, and other short fibers, will pass therethrough, whilethe longer longitudinal fibers will pass thereover..
3. The method of treating unbleached cellulosic pulp, which comprises separating the medullary ray, or other fibres of similar length from the longer longitudinal fibres of the pulp by the method which consists in flowing the pulp downwardly-over an inclined screen, the inclination of the screen and the mesh thereof being so correlated that the medullary ray, and other fibers of similar length, will pass therethrough, while the longer longitudinal fibers will pass 15c thereover, and thereafter bleaching the pulp consisting of substantially only the longer longitudinal fibers.
4. The method of treating unbleached cellulosic pulp, to separate the medullary ray, or other fibers of similar length, from the longer longitudinal fibers of the unbleached pulp, which consists in flowing the pulp downwardly over an inclined screen, the inclination of the screen and the mesh thereof being so correlated that the medullary ray, and other short fibers, will pass therethrough, while the longer longitudinal fibers will pass thereover.
5. The method of treating unbleached cellulosic pulp to separate the medullary ray, or other fibers of similar length, from the longer longitudinal fibers of the unbleached pulp, which consists in flowing the pulp, having ,a consistency of approximately 0.2 to 0.3 percent, downwardly over an inclined screen, the inclination of the screen and the mesh thereof being so correlated that the medullary ray, and other short fibers, will pass therethrough, while the longer longitudinal fibers will pass thereover.
6. The method of improving cellulosic pulp for bleaching, which comprises removing the medullary ray, or other fibers of similar length, and colloidal matter from the longer longitudinal fibers by the method which consists in flowing pulp downwardly over an inclined screen, the inclination of the-screen and the mesh thereof being so correlated that the medullary ray, and other short fibers, and the colloidal matter will pass therethrough, while the longer longitudinal fibers will pass thereover.
7. The method of improving cellulosic pulp for bleaching, which comprises removing the medullary ray, or other fibers of similar length, and
the mesh thereof being so correlated that the medullary ray, and other short fibers, and the colloidal matter will pass therethrough, while the longer longitudinal fibers will pass thereover.
8. The method of treating cellulosic pulp, which comprises separating the medullary ray, or other fibres of similar length from the longer longitudinal fibres of the pulp by the method which consists in flowing unbleached pulp downwardly over an inclined screen, the inclination of the screen and the mesh thereof being so correlated that the medullary ray, and other fibers of similar length, and colloidal matter will pass therethrough, while the longer longitudinal fibers will pass thereover, and thereafter bleaching the pulp consisting of substantially only the longer longitudinal fibers.
9. The method of treating cellulosic pulp, which comprises separating the medullary ray, or other fibres of similar length from the longer longitudinal fibres of the ..pulp by the method which consists in flowing unbleached pulp, having a consistency of approximately 0.2 to 0.3 percent, downwardly over an inclined screen, the inclination of the screen and the mesh thereof being so correlated that the medullary ray, and other fibers of similar length, and colloidal matter will pass therethrough, while the longer 1ongitudinal fibers will pass thereover, and thereafter bleaching the pulp consisting of substantially only the longer longitudinal fibers.
RAYMOND S. HATCH.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US681251A US1951017A (en) | 1933-07-20 | 1933-07-20 | Method of treating chemical pulf |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US681251A US1951017A (en) | 1933-07-20 | 1933-07-20 | Method of treating chemical pulf |
Publications (1)
Publication Number | Publication Date |
---|---|
US1951017A true US1951017A (en) | 1934-03-13 |
Family
ID=24734459
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US681251A Expired - Lifetime US1951017A (en) | 1933-07-20 | 1933-07-20 | Method of treating chemical pulf |
Country Status (1)
Country | Link |
---|---|
US (1) | US1951017A (en) |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2730932A (en) * | 1954-10-04 | 1956-01-17 | Sandy Hill Iron & Brass Works | Apparatus for interval feed and jet screening of stock |
DE969601C (en) * | 1942-11-18 | 1958-06-19 | Phrix Werke Ag | Process for the production of a low-ash pulp from annual plants suitable for chemical processing |
US2924548A (en) * | 1956-07-16 | 1960-02-09 | Masonite Corp | Process for making laminated hardboard product |
DE1119106B (en) * | 1959-03-25 | 1961-12-07 | Phrix Werke Ag | Method for producing a synthetic fiber pulp from wood u. like |
US3085927A (en) * | 1960-11-16 | 1963-04-16 | Int Paper Co | Process for preparation of fibers having differing characteristics |
US3441130A (en) * | 1967-11-30 | 1969-04-29 | Procter & Gamble | Process for the removal of fines from wood pulp fibers |
US3477571A (en) * | 1966-11-14 | 1969-11-11 | Procter & Gamble | Apparatus and method for screening fibrous slurries |
FR2406642A1 (en) * | 1977-10-20 | 1979-05-18 | Wacker Chemie Gmbh | Continuously screening shear-sensitive aq. polymer dispersions - in device contg. inclined screening plane and baffle plate enclosed in housing |
FR2436754A1 (en) * | 1978-09-21 | 1980-04-18 | Bauer Bros Co | HIGH CAPACITY SALTWATER TREATMENT SYSTEM |
EP0500109A1 (en) * | 1991-02-22 | 1992-08-26 | BHS-Bayerische Berg-, Hütten- und Salzwerke Aktiengesellschaft | Process for operating a filtration plant and filtration plant for carrying out this process |
US5228954A (en) * | 1991-05-28 | 1993-07-20 | The Procter & Gamble Cellulose Company | Cellulose pulps of selected morphology for improved paper strength potential |
US5405499A (en) * | 1993-06-24 | 1995-04-11 | The Procter & Gamble Company | Cellulose pulps having improved softness potential |
US5679218A (en) * | 1994-07-29 | 1997-10-21 | The Procter & Gamble Company | Tissue paper containing chemically softened coarse cellulose fibers |
-
1933
- 1933-07-20 US US681251A patent/US1951017A/en not_active Expired - Lifetime
Cited By (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE969601C (en) * | 1942-11-18 | 1958-06-19 | Phrix Werke Ag | Process for the production of a low-ash pulp from annual plants suitable for chemical processing |
US2730932A (en) * | 1954-10-04 | 1956-01-17 | Sandy Hill Iron & Brass Works | Apparatus for interval feed and jet screening of stock |
US2924548A (en) * | 1956-07-16 | 1960-02-09 | Masonite Corp | Process for making laminated hardboard product |
DE1119106B (en) * | 1959-03-25 | 1961-12-07 | Phrix Werke Ag | Method for producing a synthetic fiber pulp from wood u. like |
US3085927A (en) * | 1960-11-16 | 1963-04-16 | Int Paper Co | Process for preparation of fibers having differing characteristics |
US3477571A (en) * | 1966-11-14 | 1969-11-11 | Procter & Gamble | Apparatus and method for screening fibrous slurries |
US3441130A (en) * | 1967-11-30 | 1969-04-29 | Procter & Gamble | Process for the removal of fines from wood pulp fibers |
FR2406642A1 (en) * | 1977-10-20 | 1979-05-18 | Wacker Chemie Gmbh | Continuously screening shear-sensitive aq. polymer dispersions - in device contg. inclined screening plane and baffle plate enclosed in housing |
FR2436754A1 (en) * | 1978-09-21 | 1980-04-18 | Bauer Bros Co | HIGH CAPACITY SALTWATER TREATMENT SYSTEM |
EP0500109A1 (en) * | 1991-02-22 | 1992-08-26 | BHS-Bayerische Berg-, Hütten- und Salzwerke Aktiengesellschaft | Process for operating a filtration plant and filtration plant for carrying out this process |
US5228954A (en) * | 1991-05-28 | 1993-07-20 | The Procter & Gamble Cellulose Company | Cellulose pulps of selected morphology for improved paper strength potential |
US5405499A (en) * | 1993-06-24 | 1995-04-11 | The Procter & Gamble Company | Cellulose pulps having improved softness potential |
US5582685A (en) * | 1993-06-24 | 1996-12-10 | The Procter & Gamble Company | Method for producing a cellulose pulp of selected fiber length and coarseness by a two-stage fractionation |
US5679218A (en) * | 1994-07-29 | 1997-10-21 | The Procter & Gamble Company | Tissue paper containing chemically softened coarse cellulose fibers |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US1951017A (en) | Method of treating chemical pulf | |
US4332638A (en) | Method and apparatus for the recovery of a suspension of fibrous material from mixed waste paper | |
DE2540919C2 (en) | Process for the production of cellulose masses in the yield range of 65 - 95% | |
US4502918A (en) | Two-stage chemical treatment of mechanical wood pulp with sodium sulfite | |
US4435249A (en) | Process for the oxygen delignification of pulp mill rejects | |
JPH0215670B2 (en) | ||
JPS60181389A (en) | Production of improved high yield pulp | |
US3301745A (en) | Pulp processing method for mixed cellulosic materials | |
DE60038316T2 (en) | RAW MATERIAL FOR PRINTED PAPER, METHOD FOR ITS MANUFACTURE AND PRINTED PAPER | |
US2169473A (en) | Method of producing cellulose pulp | |
US5089089A (en) | System for sulfonating mechanical pulp fibers | |
US4708771A (en) | Two stage process for sulfonating mechanical pulp fibers | |
Nolan et al. | The papermaking properties of water hyacinth | |
Dadswell et al. | Influence of the morphology of woodpulp fibres on paper properties | |
US4699691A (en) | Thermomechanical digestion process | |
US2792765A (en) | Manufacture of glassine and greaseproof papers | |
US2862814A (en) | Utilization of pith in the manufacture of pulp | |
US3393121A (en) | Soda cook of acid sulfite knotter rejects | |
US2099400A (en) | Preparation of paper pulp | |
US1716006A (en) | Method of producing cellulose and paper from straw, esparto, reed, and similar raw materials | |
US1890179A (en) | Preparing refined bleached pulp | |
US2041666A (en) | Cyclic process of treating alkaline pulps | |
JPS59173395A (en) | Production of modified mechanical pulp | |
JP3592587B2 (en) | Method for producing pulp for papermaking | |
US1806309A (en) | Treatment of pulp and product of same |