CA1101383A - Method of producing smooth uniform streams of semi- pourable fibrous particles - Google Patents
Method of producing smooth uniform streams of semi- pourable fibrous particlesInfo
- Publication number
- CA1101383A CA1101383A CA324,708A CA324708A CA1101383A CA 1101383 A CA1101383 A CA 1101383A CA 324708 A CA324708 A CA 324708A CA 1101383 A CA1101383 A CA 1101383A
- Authority
- CA
- Canada
- Prior art keywords
- particles
- stream
- tubular member
- conveyor
- pourable
- 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
Links
Abstract
ABSTRACT OF THE DISCLOSURE
A method as disclosed for conversion of a stream of particulate fibrous materials that form clusters when poured from a container (semi pourable) by processing the materials through an inclined rotating tubular member having a high degree of surface roughness whereby the clusters are dispersed during travel through the tubular member for issuance as a uniform stream from the outlet thereof. The absence of clusters is particularly desirable when the stream of fibrous materials are then spread into a smooth and uniform mat to be consolidated into a molded board.
A method as disclosed for conversion of a stream of particulate fibrous materials that form clusters when poured from a container (semi pourable) by processing the materials through an inclined rotating tubular member having a high degree of surface roughness whereby the clusters are dispersed during travel through the tubular member for issuance as a uniform stream from the outlet thereof. The absence of clusters is particularly desirable when the stream of fibrous materials are then spread into a smooth and uniform mat to be consolidated into a molded board.
Description
~a~ 83 This invention relates to the processing of semi-pourable fibrous elements such as or having dimensions similar to woodenwafers, flakes or shavings in order to form a continuous uniform stream of separated wooden elements or particles available for uniform distribution in forming a mat.
In the operation of layin~ down a uniform mat of semi-pourable fibrous materials, such as short lengths of wooden strands, or wooden wafers such as described in V.S. Patent No. 2,776,687, generally satisfactory separation for doing so is described in U.S. Patent No. 3,881,225. As described in the aforementioned patent, a constant stream of particles is carried by a conveyor to the apparatus and removed from the end of the conveyor by a rapidly moving spike roll which claws off particles from the end of the oncoming stream, which particl~s are then fed into the depositing apparatus.
The spike roll is necessary because, if it is not used for semi-pourable particles, especially if they are rough and hairy or damp, the particles will break off from the conveyed stream as they are being discharged to form large clumps or clusters. The spiked roll serves markedly to reduce the size of these clumps, but if the particles are long, and especially if their surfaces are not smooth, when they are clawed off, each particle almost invariably brings adjacent particles with it, thus forming an ununiform stream of small clumps. In fact, if the stream is not large, it may even become disconnected whereby it becomes difficult if not impossible by known means to spread and ~istribute -:
. ~: . . : ~ . .
~.
.
In the operation of layin~ down a uniform mat of semi-pourable fibrous materials, such as short lengths of wooden strands, or wooden wafers such as described in V.S. Patent No. 2,776,687, generally satisfactory separation for doing so is described in U.S. Patent No. 3,881,225. As described in the aforementioned patent, a constant stream of particles is carried by a conveyor to the apparatus and removed from the end of the conveyor by a rapidly moving spike roll which claws off particles from the end of the oncoming stream, which particl~s are then fed into the depositing apparatus.
The spike roll is necessary because, if it is not used for semi-pourable particles, especially if they are rough and hairy or damp, the particles will break off from the conveyed stream as they are being discharged to form large clumps or clusters. The spiked roll serves markedly to reduce the size of these clumps, but if the particles are long, and especially if their surfaces are not smooth, when they are clawed off, each particle almost invariably brings adjacent particles with it, thus forming an ununiform stream of small clumps. In fact, if the stream is not large, it may even become disconnected whereby it becomes difficult if not impossible by known means to spread and ~istribute -:
. ~: . . : ~ . .
~.
.
- 2 - ~ 3~3 such streams of particles into a uniform, smooth mat.
It is an object of this invention to provide a method and means or breaking up such clumps or clusters of fibrous particles whereby the latter issue smoothly as a uni~orm stream of separated particles capable of being spread onto a continuously moving surface to form a smooth and uniform mat thereon.
In accordance with the invention in one aspect there is provided a method of feeding semi-pourable fibrous particles which tend to cling together as clumps or clusters to appar~tus that serves to orm the particles into a structure; the me-thod comprising the steps of first feeding the particles in-to the upper portion of a downwardly inclined conveyor and, under the influence of gravitational force and the motion of the conveyor, agitating the particles during their downward movement throu~h the conveyor to cause clusters of particles to be broken up and spaced longitudinally thus causing the particles to issue from a lower portion of the conveyor as a smooth, continuous uniform stream which is then fed directly to said apparatus.
The invention in a further aspect provides in the 2~ manufacture of an air-laid structure consisting mainly of semi pourable particles, involving the txansformation of a metered stream of said-particles into a stream of continuously uniform cross-section, the step of feeding said stream into the upper open end of a downwardly slanting rotating tube having a cross-section many times the area of said stream whereby lumps in the feed stream are dispersed and smoothed and feeding the resulting uniform stream issuing from the lower end of said tube to a distributing means to form said structure.
These and other objects and advantages of this invention will hereinafter appear and for purposes of illustration,but not of limitation, embodiments of the invention are shown in the accompanying drawing in which:
Figure 1 is a plan view in side elevation of an apparatus embodying the features of this invention, Fi~ure 2 is an end view of the apparatus shown in Figure 1, and Figure 3 is an end view of a modification of the apparatus of this invention.
~ .,.
. _ . _ , .. _ ,, .. _ _ . , .. . . . . ,, . _ ., . _ ~ . _ .. ~ . _ . _ _ . ... .. _ _ . . ... ...... .. . . . . .. ..
:, . . ~, -ll3~3 - 2a -It has been found that if such a stream containing small clumps of wooden wafers or other .~ibrous elements that are incapable of matting or clinginy together is fed into an inclined, open ended, revolving tubular member having a rough internal surface which serves bo lift the particles and allows them to fall back down during rotational movement, the clumps will be dispersed as the particles progress down the inclined tubular member so that they will be discharged from the exit end of the tubular member as a smooth and steady stream substantially ~ree of clusters. If the particles are slender, as compared to their length, especially if they also have rough surfaces or are curled, they are relatively nonpourable, except in the form of large clus-ters. However, by passing down a rotating, inclined tubular member of adequate length and diameter, they will issue in a stream as smooth and steady as if they were .
completely pourable. This assumes that the particles are not so long and so fine that they will cling firmly together and the action provided cannot separate one from anotherO
Referring now to the drawings, a metered stream \
:, . .
-31~13 of semi-pourable fibrous particles 10 is shown as being transported on the upper run of an endless belt 11 opening in a trough 12, at the end of which there is pro~ided a rapidly revolving spiked roll 13. The spiked roll claws particles and clumps of particles off the conveyor onto a downwardly inclined chute 14 and into the upper open end of an inclined tubular member 15 mounted for rotational movement. The inner surface of the tubular member 15 is roughened, such for example as by a number of longitudinally extending corrugations 16 or projections. If there is not suf~icient room availahle for a long tubular member, under some condi-tions or restrictions, a collar 17 may be provided as a dam at the exit end of the tubular member whereby the number of particles retained in the t~bular member is markedly increased before overflow. The disintegxation of clumps or clusters for separation is enhanced by reason of the additional work performed during the tumbling action of such higher concentration of fibrous particles.
The stream 19 issuing from the end of the tubular member is particularly well adapted for feeding directly into some form of particle distributing apparatus, suc~ as the felter described in U.S. Patent No. 3,881,225 to form a smooth, clump-free mat on a continuously moving collecting surface.
Experiments were conducted with a tubular member having a length of 2 meters and an internal diameter of 45 cm. A
thin metal sheet was fixed as a lining on the inner surface with circumferentially spaced apart corrugations extending lengthwise along the axis of the tubular members. One hundred 30 grams of wooden wafers each having a dimension of about -~
65 x 25 x 0.8 mm. were packed together in a round heap at the upper inlet end of the tubular member. The tubular member was rotated at various speeds within the range of 25 to 60 rpm and with the tubular member inclined at various angles within the range of 5 to 12 with the horizontal. The most most favorable conditions with the described apparatus was --a speed of about 40 rpm at an angle of 8. Under these conditions, the particles began to issue as a smooth stream .,. - -., , . ~ .
It is an object of this invention to provide a method and means or breaking up such clumps or clusters of fibrous particles whereby the latter issue smoothly as a uni~orm stream of separated particles capable of being spread onto a continuously moving surface to form a smooth and uniform mat thereon.
In accordance with the invention in one aspect there is provided a method of feeding semi-pourable fibrous particles which tend to cling together as clumps or clusters to appar~tus that serves to orm the particles into a structure; the me-thod comprising the steps of first feeding the particles in-to the upper portion of a downwardly inclined conveyor and, under the influence of gravitational force and the motion of the conveyor, agitating the particles during their downward movement throu~h the conveyor to cause clusters of particles to be broken up and spaced longitudinally thus causing the particles to issue from a lower portion of the conveyor as a smooth, continuous uniform stream which is then fed directly to said apparatus.
The invention in a further aspect provides in the 2~ manufacture of an air-laid structure consisting mainly of semi pourable particles, involving the txansformation of a metered stream of said-particles into a stream of continuously uniform cross-section, the step of feeding said stream into the upper open end of a downwardly slanting rotating tube having a cross-section many times the area of said stream whereby lumps in the feed stream are dispersed and smoothed and feeding the resulting uniform stream issuing from the lower end of said tube to a distributing means to form said structure.
These and other objects and advantages of this invention will hereinafter appear and for purposes of illustration,but not of limitation, embodiments of the invention are shown in the accompanying drawing in which:
Figure 1 is a plan view in side elevation of an apparatus embodying the features of this invention, Fi~ure 2 is an end view of the apparatus shown in Figure 1, and Figure 3 is an end view of a modification of the apparatus of this invention.
~ .,.
. _ . _ , .. _ ,, .. _ _ . , .. . . . . ,, . _ ., . _ ~ . _ .. ~ . _ . _ _ . ... .. _ _ . . ... ...... .. . . . . .. ..
:, . . ~, -ll3~3 - 2a -It has been found that if such a stream containing small clumps of wooden wafers or other .~ibrous elements that are incapable of matting or clinginy together is fed into an inclined, open ended, revolving tubular member having a rough internal surface which serves bo lift the particles and allows them to fall back down during rotational movement, the clumps will be dispersed as the particles progress down the inclined tubular member so that they will be discharged from the exit end of the tubular member as a smooth and steady stream substantially ~ree of clusters. If the particles are slender, as compared to their length, especially if they also have rough surfaces or are curled, they are relatively nonpourable, except in the form of large clus-ters. However, by passing down a rotating, inclined tubular member of adequate length and diameter, they will issue in a stream as smooth and steady as if they were .
completely pourable. This assumes that the particles are not so long and so fine that they will cling firmly together and the action provided cannot separate one from anotherO
Referring now to the drawings, a metered stream \
:, . .
-31~13 of semi-pourable fibrous particles 10 is shown as being transported on the upper run of an endless belt 11 opening in a trough 12, at the end of which there is pro~ided a rapidly revolving spiked roll 13. The spiked roll claws particles and clumps of particles off the conveyor onto a downwardly inclined chute 14 and into the upper open end of an inclined tubular member 15 mounted for rotational movement. The inner surface of the tubular member 15 is roughened, such for example as by a number of longitudinally extending corrugations 16 or projections. If there is not suf~icient room availahle for a long tubular member, under some condi-tions or restrictions, a collar 17 may be provided as a dam at the exit end of the tubular member whereby the number of particles retained in the t~bular member is markedly increased before overflow. The disintegxation of clumps or clusters for separation is enhanced by reason of the additional work performed during the tumbling action of such higher concentration of fibrous particles.
The stream 19 issuing from the end of the tubular member is particularly well adapted for feeding directly into some form of particle distributing apparatus, suc~ as the felter described in U.S. Patent No. 3,881,225 to form a smooth, clump-free mat on a continuously moving collecting surface.
Experiments were conducted with a tubular member having a length of 2 meters and an internal diameter of 45 cm. A
thin metal sheet was fixed as a lining on the inner surface with circumferentially spaced apart corrugations extending lengthwise along the axis of the tubular members. One hundred 30 grams of wooden wafers each having a dimension of about -~
65 x 25 x 0.8 mm. were packed together in a round heap at the upper inlet end of the tubular member. The tubular member was rotated at various speeds within the range of 25 to 60 rpm and with the tubular member inclined at various angles within the range of 5 to 12 with the horizontal. The most most favorable conditions with the described apparatus was --a speed of about 40 rpm at an angle of 8. Under these conditions, the particles began to issue as a smooth stream .,. - -., , . ~ .
3~il3 from the exit end beginning at 7 seconds and terminatingat about 13 seconds. The wafers issued at a uniform rate after a steady state was reached through the period of 7 to 13 seconds. At an angle of 12, the resident time within the tubular member was from 5 to 9 seconds, depending on the speed of rotation.
It will be obvious that the continual addition of clusters of wafers to the upper feed end of the rotating tubular member will enable it to deliver an unexpectedly uniform and continuous smooth flow of particles from the lower exit end.
Because of the difficulty of feeding a uniorm s~ream of fibrous materials into a felter of the type described in U.S. Patent No. 2,770,844 despite its other-wise obvious advantages, it has not been widely used. The method of this invention provides, for the first time, means for converting a stream of resinous coated elongate fibrous particles for feeding a device o~ the type described in the aforementioned patents whereby a uniform mat can be obtained on a movin~ collecting surface and a board can be obtained by compression at elevated temperature having a hitherto unobtainable uniform density throughout the cross section. The latter is very important since, if the body of the board is formed containing aggregates of fibrous particles, the smooth flat surface imparted by the press will subsequently become uneven when the board is exposed to moisture or high humidity or, if such a board is veneered, the denser aggregates and the areas of lesser density will be "telegraphed" to the outer surface of the veneer and ruin its appearance.
The extent to which the bundles or semi-pourable wooden or fibrous particles or wafers are subjectea to the tumblingaction for separation will depend somewhat on the angle of inclination of the tubular member, its diameter, length, and rate of rotation. The rate of rotation of the tubular member should be less than that at which the particles will be held at centrifugal force to the walls , :
.
13~
of the tubular member unless the modified apparatus shown in Fig. 3 is employed. With a diameter of about 30-60 cm the desired results can be achieved with a rate of rotation within the range of 10 to 75 rpm and preferably about 30 to 50 rpm.
The angle of inclination can be varied through a wide ran~e depending on the dimensions oE the apparatus, but it is preferred to dispose the tubular member having approximately the dimensions and conditions previously discussed for rotation about an axis inclined at an angle within the range of 5-15 and preferably 6-10 with the horizo~tal. The length of the tubular member will depend somewhat upon the angle of inclinatlon, as indicated in the preceding example. Under the conditions described wherein the tubular member is dis-posed at a slope of 5-15, revolves at a rate of 15-75 rpm and has an internal diameter within the range of 30-60 cm, the desired results can be achieved with a tubular member having a length of from 1 to 5 m. It is desirable to make use of a length whereby the resident time of the particles for tumbling action within the tubular member will be at least 5 seconds and more if the particles are not easily separated. While the resident time can exceed one minute, little if any additional benefit is achleved.
The desired configuration or surface roughness on the inner wall of the tubular member or trough can be achieved by the use of spaced longitudinal narrow strips of metal~
Alternatively, the surface configuration can be in the form of corrugations, dimples, cross hatching or in the form of an abraded surface to which the particles will tend to cling.
As indicated in Fig. 3, it is possible to achieve the objectives by speeding up the tubular member sufficiently to cause the particles to cling to the surface by centrifugal force, then use a long scraper fixed along the top of the member to remove and agitate them so they fall and progress down the tube. The angle of inclination of the member may then be increased beyond 15 if desired.
It will be understood that changes may be made in . :
~ ~ .
3~;~
the details of construction, arrangement ~nd operation with-out departing from the spirit of the invention, especially as defined in the following claims.
,: , -: .
- :
- .
,~ , - - : :. . , : ,
It will be obvious that the continual addition of clusters of wafers to the upper feed end of the rotating tubular member will enable it to deliver an unexpectedly uniform and continuous smooth flow of particles from the lower exit end.
Because of the difficulty of feeding a uniorm s~ream of fibrous materials into a felter of the type described in U.S. Patent No. 2,770,844 despite its other-wise obvious advantages, it has not been widely used. The method of this invention provides, for the first time, means for converting a stream of resinous coated elongate fibrous particles for feeding a device o~ the type described in the aforementioned patents whereby a uniform mat can be obtained on a movin~ collecting surface and a board can be obtained by compression at elevated temperature having a hitherto unobtainable uniform density throughout the cross section. The latter is very important since, if the body of the board is formed containing aggregates of fibrous particles, the smooth flat surface imparted by the press will subsequently become uneven when the board is exposed to moisture or high humidity or, if such a board is veneered, the denser aggregates and the areas of lesser density will be "telegraphed" to the outer surface of the veneer and ruin its appearance.
The extent to which the bundles or semi-pourable wooden or fibrous particles or wafers are subjectea to the tumblingaction for separation will depend somewhat on the angle of inclination of the tubular member, its diameter, length, and rate of rotation. The rate of rotation of the tubular member should be less than that at which the particles will be held at centrifugal force to the walls , :
.
13~
of the tubular member unless the modified apparatus shown in Fig. 3 is employed. With a diameter of about 30-60 cm the desired results can be achieved with a rate of rotation within the range of 10 to 75 rpm and preferably about 30 to 50 rpm.
The angle of inclination can be varied through a wide ran~e depending on the dimensions oE the apparatus, but it is preferred to dispose the tubular member having approximately the dimensions and conditions previously discussed for rotation about an axis inclined at an angle within the range of 5-15 and preferably 6-10 with the horizo~tal. The length of the tubular member will depend somewhat upon the angle of inclinatlon, as indicated in the preceding example. Under the conditions described wherein the tubular member is dis-posed at a slope of 5-15, revolves at a rate of 15-75 rpm and has an internal diameter within the range of 30-60 cm, the desired results can be achieved with a tubular member having a length of from 1 to 5 m. It is desirable to make use of a length whereby the resident time of the particles for tumbling action within the tubular member will be at least 5 seconds and more if the particles are not easily separated. While the resident time can exceed one minute, little if any additional benefit is achleved.
The desired configuration or surface roughness on the inner wall of the tubular member or trough can be achieved by the use of spaced longitudinal narrow strips of metal~
Alternatively, the surface configuration can be in the form of corrugations, dimples, cross hatching or in the form of an abraded surface to which the particles will tend to cling.
As indicated in Fig. 3, it is possible to achieve the objectives by speeding up the tubular member sufficiently to cause the particles to cling to the surface by centrifugal force, then use a long scraper fixed along the top of the member to remove and agitate them so they fall and progress down the tube. The angle of inclination of the member may then be increased beyond 15 if desired.
It will be understood that changes may be made in . :
~ ~ .
3~;~
the details of construction, arrangement ~nd operation with-out departing from the spirit of the invention, especially as defined in the following claims.
,: , -: .
- :
- .
,~ , - - : :. . , : ,
Claims (8)
1. A method of feeding semi-pourable fibrous particles which tend to cling together as clumps or clusters to apparatus that serves to form the particles into a structure;
the method comprising the steps of first feeding the particles into the upper portion of a downwardly inclined conveyor and, under the influence of gravitational force and the motion of the conveyor, agitating the particles during their downward movement through the conveyor to cause clusters of particles to be broken up and spaced longitudinally thus causing the particles to issue from a lower portion of the conveyor as a smooth, continuous uniform stream which is then fed directly to said apparatus.
the method comprising the steps of first feeding the particles into the upper portion of a downwardly inclined conveyor and, under the influence of gravitational force and the motion of the conveyor, agitating the particles during their downward movement through the conveyor to cause clusters of particles to be broken up and spaced longitudinally thus causing the particles to issue from a lower portion of the conveyor as a smooth, continuous uniform stream which is then fed directly to said apparatus.
2. The method as claimed in Claim 1, in which the semi-pourable fibrous particles have the form of wood wafers, flakes or shavings.
3. The method as claimed in Claim l, in which the conveyor comprises a rotatable,inclined tubular member having a cross-sectional area many times that of said stream, the internal surface of which is characterized by uneven-ness capable of raising and longitudinally spreading the particles during rotation of the tubular member.
4. The method as claimed in Claim 3, in which the surface unevenness comprises axially extending corrugations.
5. The method as claimed in Claim 3, in which the tubular member has a diameter within the range of 30-60 cm, a length within the range of 1-5 meters, is mounted at a slope within the range of 5-15° and is rotated at a rate of 15-75 rpm.
6. The method as claimed in Claim 1, in which the particles have a resident time of at least 5 seconds during processing through the conveyor.
7. The method as claimed in Claim 1 in which the downwardly inclined conveyor comprises a tubular member having a cross-sectional area many times that of the stream, and in which the tubular member is rotated at a speed sufficient to cause the particles to cling to the surface by centrifugal force and which includes the step of scraping the internal surface of the tubular member in the top por-tion to remove the particles from the surface whereafter the particles fall gravitationally and mix and join the downward oncoming stream of particles.
8. In the manufacture of an air-laid structure con-sisting mainly of semi-pourable particles, involving the trans-formation of a metered stream of said particles into a stream of continuously uniform cross-section, the step of feeding said stream into the upper open end of a downwardly slanting rotating tube having a cross-section many times the area of said stream whereby lumps in the feed stream are dispersed and smoothed and feeding the resulting uniform stream issuing from the lower end of said tube to a distri-buting means to form said structure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA324,708A CA1101383A (en) | 1979-03-30 | 1979-03-30 | Method of producing smooth uniform streams of semi- pourable fibrous particles |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA324,708A CA1101383A (en) | 1979-03-30 | 1979-03-30 | Method of producing smooth uniform streams of semi- pourable fibrous particles |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1101383A true CA1101383A (en) | 1981-05-19 |
Family
ID=4113906
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA324,708A Expired CA1101383A (en) | 1979-03-30 | 1979-03-30 | Method of producing smooth uniform streams of semi- pourable fibrous particles |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1101383A (en) |
-
1979
- 1979-03-30 CA CA324,708A patent/CA1101383A/en not_active Expired
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3644078A (en) | Apparatus for producing nonwoven fabrics | |
| US2317895A (en) | Means for and method of manufacturing mineral wool products by the "dry" process | |
| FI62818C (en) | SAETT ATT FOERBEREDA FIBERKNIPPEN FOER RIKTAD INBLANDNING I SPUTBETONG OCH ANORDNING FOER GENOMFOERANDE AV SAETTET | |
| US4157724A (en) | Method and an apparatus for distributing a disintegrated material onto a layer forming surface | |
| US4478896A (en) | Apparatus for blending wood strands with a liquid resin | |
| AU622645B2 (en) | Non-woven article made of a heat-resisting material, method for manufacturing the article and apparatus for implementing the method | |
| EP0188454A1 (en) | A dry forming system for fiber products. | |
| US2601355A (en) | Apparatus for impregnating pourable material such as chips, shavings, and fibrous material | |
| US2689975A (en) | Apparatus and method for producing building boards | |
| US3564083A (en) | Formation of fibrous granules | |
| US4378871A (en) | Method of producing smooth-uniform streams of semi-pourable fibrous particles | |
| CA1101383A (en) | Method of producing smooth uniform streams of semi- pourable fibrous particles | |
| US2579770A (en) | Fiber dispersing machine and method | |
| EP0337094B1 (en) | Agglomeration | |
| JP2004337161A (en) | Method for producing fleece continuous material and apparatus for the same | |
| US4954060A (en) | Apparatus for agglomeration | |
| US4742622A (en) | Flighting for horizontal dryers | |
| JP2004337159A (en) | Method for preparing cut fiber and apparatus for preparing the cut fiber used for producing filter | |
| JP4512397B2 (en) | Method and apparatus for producing fleeces for producing filter rods | |
| US2717538A (en) | Method and apparatus for fissuring fibrous materials | |
| AU660174B2 (en) | Distributor for particulate material | |
| JPS58162279A (en) | Method and apparatus for treating leaf pieces and stalk of tobacco | |
| RU2183510C2 (en) | Powder sprayer | |
| US2748429A (en) | Apparatus for forming fibrous structures | |
| CN211513445U (en) | High-efficient centrifugal spray drier |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |