CA1044887A - Web dryer with graded apertures - Google Patents
Web dryer with graded aperturesInfo
- Publication number
- CA1044887A CA1044887A CA207,937A CA207937A CA1044887A CA 1044887 A CA1044887 A CA 1044887A CA 207937 A CA207937 A CA 207937A CA 1044887 A CA1044887 A CA 1044887A
- Authority
- CA
- Canada
- Prior art keywords
- web
- plate
- impingement
- drying
- air
- 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
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B13/00—Machines and apparatus for drying fabrics, fibres, yarns, or other materials in long lengths, with progressive movement
- F26B13/10—Arrangements for feeding, heating or supporting materials; Controlling movement, tension or position of materials
- F26B13/101—Supporting materials without tension, e.g. on or between foraminous belts
- F26B13/104—Supporting materials without tension, e.g. on or between foraminous belts supported by fluid jets only; Fluid blowing arrangements for flotation dryers, e.g. coanda nozzles
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F5/00—Dryer section of machines for making continuous webs of paper
- D21F5/18—Drying webs by hot air
- D21F5/185—Supporting webs in hot air dryers
- D21F5/187—Supporting webs in hot air dryers by air jets
- D21F5/188—Blowing devices
Landscapes
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Drying Of Solid Materials (AREA)
- Paper (AREA)
- Nozzles (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Method and apparatus for drying a moving web of paper or the like including one or more impingement boxes which are disposed in spaced relation to the moving web, means for introducing pressurized air into each of the impingement boxes, each of the boxes including an apertured plate spaced from the web being dried, the plate having relatively small diameter holes centrally thereof and relatively larger diameter holes along the leading and trailing edges to minimize cross flow interference with exhaust spaces being provided along the leading and trailing edges for directing spent drying air into an exhaust plenum.
Method and apparatus for drying a moving web of paper or the like including one or more impingement boxes which are disposed in spaced relation to the moving web, means for introducing pressurized air into each of the impingement boxes, each of the boxes including an apertured plate spaced from the web being dried, the plate having relatively small diameter holes centrally thereof and relatively larger diameter holes along the leading and trailing edges to minimize cross flow interference with exhaust spaces being provided along the leading and trailing edges for directing spent drying air into an exhaust plenum.
Description
10~8 ;~
BACKGROUND OF THE INVENTION
Field of the Invention This invention is in the field of drying webs of paper and the like ~y means of impingement flow, the geometry of the imping~ment means and the proces~ variables being controlled to provide high heat transfer rates with a minimum of cross flow interference and a minimum pre~ure gradient exi~ting between impingement jets located at various distances fro~ the exhaust openings .
DESCRIPrION OF THE PRIOR ART
Impingement flow, that i8, flow directed normal to the surface has been recognized as an efficient means for heating or cooling~ In recent years, this method of heat transfer has been used in the paper industry for drying of paper. Represen-tative patents in thi~ field are U.S. Patents NosO 3,163,502 issued December 29, 1964 to Edgar J. Justin and Loyal H. Hess;
3,167, 408 issued J~nuary 26, 1965 to Edgar J. Justin and Loyal H. ~ess and 3,447~247 issued June 3, 1969 to Robert A. Daane.
Air impingement drying is particularly suited for drying ~0 of lightweight grades of paper such as tissue paper and for drying coated paper. These applications require higher rates of heat transfer because of tho limited drying length and the requirements of high speed operationO
There are various type~ of air impingement devices in use on paper drying apparatus. One of these types uses slotted nozzles and another incorporates round hole~ to provide jet orifices for Lmpingement purposes. The slot nozzle arrangements have the disadvantage of requiring a relatively complex system of air removal ducts between the slots. Slot arrangements are 10~
also characterized by inefficient performance as measured by the heat transfer coefficient obtainable for a given expenditure of air blower horsepower. In addition, relatively small spacings between the impingement surface and the slot nozzles are re-quired in order to obtain good heat transfer resultsO
Some of the disadvan~ages inherent in the slot nozzle arrangement are eliminated in the round hole impingement systems.
For example, the heat transfer coefficient i8 relatively un-a fected by the distance from the nozzle to the impingement surface as long as there is a proper ratio of the impingement distance to the hole diameterO Also when using round impingement holes, it becomes easier to incorporate air exhaust sy~tems be-tween sets of the round holes.
With the demand for increased machine speeds, adequate drying must either be accomplished by raising the drying rate or the heat transfer lengthO Increased drying lengths require additional capital expenditure for already expensive drying equipment. In tissue drying applications, where the wet web is pressed on the surface of a large diameter rotating drum, the web must be dried in less than one revolution. Typically, such a drying system employs a large diameter steam filled cylinder surrounded by a high temperature, high velocity air impingement cap. However, these steam filled cylinders are already operating at about the highest practical steam pressures poqsible and are being built at about the largest practical diameter posæible.
Therefore, any further increases in speed must come from in-creased heat transfer rates from air impingement. At the pre-sent time, air caps are being operated at temperatures of about 800F. In order to achieve higher temperatures, expensive high temperature alloy~ must be employed. In addition, at these higher temperatures problems are encountered in maintaining the dimensional stability of the equipment and as impingement temperatures get higher, more problems will be encountered with drying uniformity.
Inasmuch as air caps in use today in the paper industry are already operating at about the limit of temperature, it be-comes necessary to increase the convective heat transfer co-efficient in order to increase the heat transfer rate and consequently the evaporation rate. In paper drying applications, a large convective heat transfer coefficient helps to alleviate any nonuniform drying problems. One method of increa~ing the convective heat transfer coefficient is simply by increasing the impingement velocity. However, for a given system con-figuration an increase in impingement velocity can only be obtained at the expense of increased fan horsepower~ Increases in fan horsepower represent both increaQed capital cost for equipment and also increased operating expense. Therefore, an upper limit exists whereby increases in heat transfer rate by adding additional fan horsepower are no longer considered feasible.
Another means of increasing the heat transfer coefficient is to increa-~e the number of impinging jets, that is, by in-creasing the open area of the impingement plate. Published literature indicates that after the open areais increased be-yond approximately 2%, no further gains in the heat transfer rate are obtainable. It was thought that the inability to improve the heat transfer rate was caused by interference be-tween adjacent impinging jets, that is, as the open area was increased and the impingement jets became closer and closer ~0~ 7 together, the adjacent jet~ interefered with each other thereby reducing the heat transfer coefficientO
More recently publi~hed experimental data indicates that this reduction in heat transfer coefficient i8 not caused by interference between adjacent jet~ but rather by cross flow interference from the spent airO The jets after impingement must travel to an opening to be exhau~ted and thi~ mean~ that khe spent air must travel across adjacent jets before reaching an exhaust outletO This exhaust cross flow interference can actually cause the impinging jet to be bent at an angle which i8 not perpendicular to the surface of impingement. Any devia-tion of the impingement jet from a line normal to the heated or cooled surface results in a degradation of the heat transfer rateO Consequently, it becomes important to eliminate or re-duce cross flow interference if the average heat transfer co-efficient is to be increased.
SUMMARY OF THE INVE~TION
This invention relateæ to a method and apparatus for impingement drying by means of which high heat transfer rates are obtained. Cro~s flow interference caused by spent air interfering with the impingement jets as it flows towards the exhaust pas~ages i9 minimized while using a minimum number of exhaust openings, thus reducing the complexity of fabricating the air Lmpingement system. With the method and apparatu~ of the present invention~ the pres~ure gradient existing between jet~ located at various distances from the exhauQt openings i8 minimized. The apparatus of the present invention i~ relatively simple to con~truct and install, thereby significantly reducing the cost.
we have found that these improvements can be obtained by utilizing one or more impingement boxes extending across the width of the web to be dried in spaced relation, with the spacing between the boxe~ being sufficient to provide exhaust passages for exhausting drying air~ Each of the impingement boxes is supplied with pressurized air. Each of the boxes includes an apertured plate spaced from the web being dried, the plate having relatively small diameter holes centrally thereof and relatively larger diameter holes along the edges thereof which adjoin the exhaust passages. The spacing of the individual holes from the web and the diameters of the holes are so arranged 80 that each hole is spaced from the web by no more than four times the dia-meter of the hole, and is located preferably at a spacing which is from 1 to 4 times the diametsr of the particular holeO
BRIEF DESCRIPTIO~ OF THE DRAWINGS
Other objects, features and advantages of the invention will be readily apparent from the following description of cer-~ain preferred embodiments thereof, taken in conjunction with the accompanying drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure, and in which:
Pigure 1 is a fragmentary cross-sectional view taken substantially along the line I-I of Figure 2;
Figure 2 is a view partly in elevation and partly in cross-section of one impingement box used according to the present invention; and Figure 3 is a rather schematic view partially broken away of an entire air impingement system embodying the improve-ments of the present invention.
DESCRIPTION OE THE PREFERRED EM~ODIMENTS
Referring first to Figure 39 reference numeral 10 ha~
been applied generally to an air impingement drying system which includes a manifold 11 in which are supported a plurality of impingement boxes 12 to 15, inclusive. Each of the boxe~ 12 to 15 are located in closely spaced relation to a traveling web 16 of paper or the like. Individual inlet conduit~ 17 through 20 supply pre~urized air to the boxes 12 to 15, respectively.
The traveling web 16 is carried on a supporting sur~ace 35 such a~ a belt or a drum surface spaced a predetermined distance from the boxesO
The boxes 12 to 15 are ~paced from the wall~ of the manifold 11 and from each other to provide exhaust passages 21 to 25 therebetween. The ~pent drying air after impingement against the surface of the web 16 i8 channeled into the exhaust spaces 21 to 25 and collected in an exhaust plenum 26 behind the boxes 12 to 15, inclusive, from which the spent drying air can be vented by means of an exhaust conduit 270 Each of the boxes 12 to 15, inclusive, has an apertured p}ate 28 closing off the bottom end of the boxes, one of which is illustrated in Figures 1 and 2 of the drawings. Each of the plate~ 28 has a plurality of relatively Qmall diameter holes 29 located centrally of the plate and between a series of inter-mediate diameter holes 30 and 31 on opposite sides thereof.
~arger diameter holes 32 and 33 are arranged in rows closely ad-jacent the re~pective exhaust spaces 22 and 23 as best illuQ-trated in Figure 1.
While the ~ize of the holes 29, 30 and 32 may be varied depending upon the nature of the material being dried and other factor~, the smallest diameter apertures should have diameters on the order of l/16 or l/8 inch and the larger diameter apertures may range up to 3/4 of an inch or more. The most important parameter from the standpoint of the present inve~ ion is the relationship between the hole diameter and its vertical distance to the surface of the web 16. We have found that the ratio of spacing of a given hole to the web should be no more than four times the diameter of the hole and preferably the spacing should be from 1 to 4 time~ that diameter. In the form of the invention shown in Figures l and 2, the apertured plate 28 is curved 80 that substantially the same ratio of distance to diameter exists for the small diameter hole~ 29 which are spaced a relatively short distance from the web 16, and the larger diameter holes 32 and 33 which are spaced a larger vertical distance from the surface of the web.
It i9 also possible to employ the improvements of the present invention using a substantially flat apertured plate in conjunction with drying of a paper web on the surface of a rotary cylinder or other arcuate surface where the geometry of the cylinder itself provides the requisite correlation between the aperture size and its distance from the webO
With the system of the present invention, high tempera-ture high pressure air having a velocity on the order of 20,000 to 30,000 feet per minute can be employed as a drying medium while utilizing a web speed of lightweight paper of about 4,000 to 6,500 feet per minute.
With the arrangement described, the small impingement holes 29 are located where cross flow interference is at a minimum and the larger diameter holes 32 and 33, which are least effected by cros~ flow i ~e~erence, are located where the cross flow is highest. Thi4 arrangement provides high heat transfer with a minimum of exhaust openings. By providing in-creased vertical spacing for the large diameter holes 32 and 33, the cross flow area is increased and hence the cross flow velocitics are decreased. Not only does thi~ variable vertical spacing minimize the cross flow interference but it also sub-stantially reduces the pressure gradient in the axial direction, resulting in more uniform and efficient heat tran~fer.
In the described system~ the exhaust pasRages are located between each of the impingement boxes and the exhaust is collect-ed in a central plenum cha~ber -qurrounding all of the impingement boxes. This places the lower temperature exhaust air around the impingement boxes, minimizing the need for insulating the boxes to prevent heat lo~ses to the surrounding~. Another ad-vantage of this system is that the metal ducts eliminate much of the extensive fabrication associated with conventional air impingement devicesO
It should be evident that various modifications can be made to the described embodiments without departing from the scope of the present invention.
BACKGROUND OF THE INVENTION
Field of the Invention This invention is in the field of drying webs of paper and the like ~y means of impingement flow, the geometry of the imping~ment means and the proces~ variables being controlled to provide high heat transfer rates with a minimum of cross flow interference and a minimum pre~ure gradient exi~ting between impingement jets located at various distances fro~ the exhaust openings .
DESCRIPrION OF THE PRIOR ART
Impingement flow, that i8, flow directed normal to the surface has been recognized as an efficient means for heating or cooling~ In recent years, this method of heat transfer has been used in the paper industry for drying of paper. Represen-tative patents in thi~ field are U.S. Patents NosO 3,163,502 issued December 29, 1964 to Edgar J. Justin and Loyal H. Hess;
3,167, 408 issued J~nuary 26, 1965 to Edgar J. Justin and Loyal H. ~ess and 3,447~247 issued June 3, 1969 to Robert A. Daane.
Air impingement drying is particularly suited for drying ~0 of lightweight grades of paper such as tissue paper and for drying coated paper. These applications require higher rates of heat transfer because of tho limited drying length and the requirements of high speed operationO
There are various type~ of air impingement devices in use on paper drying apparatus. One of these types uses slotted nozzles and another incorporates round hole~ to provide jet orifices for Lmpingement purposes. The slot nozzle arrangements have the disadvantage of requiring a relatively complex system of air removal ducts between the slots. Slot arrangements are 10~
also characterized by inefficient performance as measured by the heat transfer coefficient obtainable for a given expenditure of air blower horsepower. In addition, relatively small spacings between the impingement surface and the slot nozzles are re-quired in order to obtain good heat transfer resultsO
Some of the disadvan~ages inherent in the slot nozzle arrangement are eliminated in the round hole impingement systems.
For example, the heat transfer coefficient i8 relatively un-a fected by the distance from the nozzle to the impingement surface as long as there is a proper ratio of the impingement distance to the hole diameterO Also when using round impingement holes, it becomes easier to incorporate air exhaust sy~tems be-tween sets of the round holes.
With the demand for increased machine speeds, adequate drying must either be accomplished by raising the drying rate or the heat transfer lengthO Increased drying lengths require additional capital expenditure for already expensive drying equipment. In tissue drying applications, where the wet web is pressed on the surface of a large diameter rotating drum, the web must be dried in less than one revolution. Typically, such a drying system employs a large diameter steam filled cylinder surrounded by a high temperature, high velocity air impingement cap. However, these steam filled cylinders are already operating at about the highest practical steam pressures poqsible and are being built at about the largest practical diameter posæible.
Therefore, any further increases in speed must come from in-creased heat transfer rates from air impingement. At the pre-sent time, air caps are being operated at temperatures of about 800F. In order to achieve higher temperatures, expensive high temperature alloy~ must be employed. In addition, at these higher temperatures problems are encountered in maintaining the dimensional stability of the equipment and as impingement temperatures get higher, more problems will be encountered with drying uniformity.
Inasmuch as air caps in use today in the paper industry are already operating at about the limit of temperature, it be-comes necessary to increase the convective heat transfer co-efficient in order to increase the heat transfer rate and consequently the evaporation rate. In paper drying applications, a large convective heat transfer coefficient helps to alleviate any nonuniform drying problems. One method of increa~ing the convective heat transfer coefficient is simply by increasing the impingement velocity. However, for a given system con-figuration an increase in impingement velocity can only be obtained at the expense of increased fan horsepower~ Increases in fan horsepower represent both increaQed capital cost for equipment and also increased operating expense. Therefore, an upper limit exists whereby increases in heat transfer rate by adding additional fan horsepower are no longer considered feasible.
Another means of increasing the heat transfer coefficient is to increa-~e the number of impinging jets, that is, by in-creasing the open area of the impingement plate. Published literature indicates that after the open areais increased be-yond approximately 2%, no further gains in the heat transfer rate are obtainable. It was thought that the inability to improve the heat transfer rate was caused by interference be-tween adjacent impinging jets, that is, as the open area was increased and the impingement jets became closer and closer ~0~ 7 together, the adjacent jet~ interefered with each other thereby reducing the heat transfer coefficientO
More recently publi~hed experimental data indicates that this reduction in heat transfer coefficient i8 not caused by interference between adjacent jet~ but rather by cross flow interference from the spent airO The jets after impingement must travel to an opening to be exhau~ted and thi~ mean~ that khe spent air must travel across adjacent jets before reaching an exhaust outletO This exhaust cross flow interference can actually cause the impinging jet to be bent at an angle which i8 not perpendicular to the surface of impingement. Any devia-tion of the impingement jet from a line normal to the heated or cooled surface results in a degradation of the heat transfer rateO Consequently, it becomes important to eliminate or re-duce cross flow interference if the average heat transfer co-efficient is to be increased.
SUMMARY OF THE INVE~TION
This invention relateæ to a method and apparatus for impingement drying by means of which high heat transfer rates are obtained. Cro~s flow interference caused by spent air interfering with the impingement jets as it flows towards the exhaust pas~ages i9 minimized while using a minimum number of exhaust openings, thus reducing the complexity of fabricating the air Lmpingement system. With the method and apparatu~ of the present invention~ the pres~ure gradient existing between jet~ located at various distances from the exhauQt openings i8 minimized. The apparatus of the present invention i~ relatively simple to con~truct and install, thereby significantly reducing the cost.
we have found that these improvements can be obtained by utilizing one or more impingement boxes extending across the width of the web to be dried in spaced relation, with the spacing between the boxe~ being sufficient to provide exhaust passages for exhausting drying air~ Each of the impingement boxes is supplied with pressurized air. Each of the boxes includes an apertured plate spaced from the web being dried, the plate having relatively small diameter holes centrally thereof and relatively larger diameter holes along the edges thereof which adjoin the exhaust passages. The spacing of the individual holes from the web and the diameters of the holes are so arranged 80 that each hole is spaced from the web by no more than four times the dia-meter of the hole, and is located preferably at a spacing which is from 1 to 4 times the diametsr of the particular holeO
BRIEF DESCRIPTIO~ OF THE DRAWINGS
Other objects, features and advantages of the invention will be readily apparent from the following description of cer-~ain preferred embodiments thereof, taken in conjunction with the accompanying drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure, and in which:
Pigure 1 is a fragmentary cross-sectional view taken substantially along the line I-I of Figure 2;
Figure 2 is a view partly in elevation and partly in cross-section of one impingement box used according to the present invention; and Figure 3 is a rather schematic view partially broken away of an entire air impingement system embodying the improve-ments of the present invention.
DESCRIPTION OE THE PREFERRED EM~ODIMENTS
Referring first to Figure 39 reference numeral 10 ha~
been applied generally to an air impingement drying system which includes a manifold 11 in which are supported a plurality of impingement boxes 12 to 15, inclusive. Each of the boxe~ 12 to 15 are located in closely spaced relation to a traveling web 16 of paper or the like. Individual inlet conduit~ 17 through 20 supply pre~urized air to the boxes 12 to 15, respectively.
The traveling web 16 is carried on a supporting sur~ace 35 such a~ a belt or a drum surface spaced a predetermined distance from the boxesO
The boxes 12 to 15 are ~paced from the wall~ of the manifold 11 and from each other to provide exhaust passages 21 to 25 therebetween. The ~pent drying air after impingement against the surface of the web 16 i8 channeled into the exhaust spaces 21 to 25 and collected in an exhaust plenum 26 behind the boxes 12 to 15, inclusive, from which the spent drying air can be vented by means of an exhaust conduit 270 Each of the boxes 12 to 15, inclusive, has an apertured p}ate 28 closing off the bottom end of the boxes, one of which is illustrated in Figures 1 and 2 of the drawings. Each of the plate~ 28 has a plurality of relatively Qmall diameter holes 29 located centrally of the plate and between a series of inter-mediate diameter holes 30 and 31 on opposite sides thereof.
~arger diameter holes 32 and 33 are arranged in rows closely ad-jacent the re~pective exhaust spaces 22 and 23 as best illuQ-trated in Figure 1.
While the ~ize of the holes 29, 30 and 32 may be varied depending upon the nature of the material being dried and other factor~, the smallest diameter apertures should have diameters on the order of l/16 or l/8 inch and the larger diameter apertures may range up to 3/4 of an inch or more. The most important parameter from the standpoint of the present inve~ ion is the relationship between the hole diameter and its vertical distance to the surface of the web 16. We have found that the ratio of spacing of a given hole to the web should be no more than four times the diameter of the hole and preferably the spacing should be from 1 to 4 time~ that diameter. In the form of the invention shown in Figures l and 2, the apertured plate 28 is curved 80 that substantially the same ratio of distance to diameter exists for the small diameter hole~ 29 which are spaced a relatively short distance from the web 16, and the larger diameter holes 32 and 33 which are spaced a larger vertical distance from the surface of the web.
It i9 also possible to employ the improvements of the present invention using a substantially flat apertured plate in conjunction with drying of a paper web on the surface of a rotary cylinder or other arcuate surface where the geometry of the cylinder itself provides the requisite correlation between the aperture size and its distance from the webO
With the system of the present invention, high tempera-ture high pressure air having a velocity on the order of 20,000 to 30,000 feet per minute can be employed as a drying medium while utilizing a web speed of lightweight paper of about 4,000 to 6,500 feet per minute.
With the arrangement described, the small impingement holes 29 are located where cross flow interference is at a minimum and the larger diameter holes 32 and 33, which are least effected by cros~ flow i ~e~erence, are located where the cross flow is highest. Thi4 arrangement provides high heat transfer with a minimum of exhaust openings. By providing in-creased vertical spacing for the large diameter holes 32 and 33, the cross flow area is increased and hence the cross flow velocitics are decreased. Not only does thi~ variable vertical spacing minimize the cross flow interference but it also sub-stantially reduces the pressure gradient in the axial direction, resulting in more uniform and efficient heat tran~fer.
In the described system~ the exhaust pasRages are located between each of the impingement boxes and the exhaust is collect-ed in a central plenum cha~ber -qurrounding all of the impingement boxes. This places the lower temperature exhaust air around the impingement boxes, minimizing the need for insulating the boxes to prevent heat lo~ses to the surrounding~. Another ad-vantage of this system is that the metal ducts eliminate much of the extensive fabrication associated with conventional air impingement devicesO
It should be evident that various modifications can be made to the described embodiments without departing from the scope of the present invention.
Claims (2)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An apparatus for drying a moving web comprising a housing, a smoothly curved apertured plate closing off the housing and extending the width of said web, means for introducing pressurized air into said housing for flow through said plate, an exhaust means extending the width of said web for exhausting spent air at the edges of the plate, the apertures in said plate including small diameter holes normal to the plane of the web located centrally of said plate and large diameter holes normal to the plane of the web located at the edges of said plate and in close proximity and parallel to said exhaust means, said small diameter holes being in closer proximity to the web than the larger diameter holes so that increased volume of cross row spent air occurs at the plate edge at the location of the larger holes with higher volume air jets.
2. The apparatus of claim 1 in which the diameter of all said holes and their spacing from the web is such that the spacing of any given hole from the web is not greater than four times its diameter.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US424644A US3895449A (en) | 1973-10-10 | 1973-12-14 | Air impingement system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1044887A true CA1044887A (en) | 1978-12-26 |
Family
ID=23683349
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA207,937A Expired CA1044887A (en) | 1973-12-14 | 1974-08-27 | Web dryer with graded apertures |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS5091869A (en) |
| BR (1) | BR7409910A (en) |
| CA (1) | CA1044887A (en) |
| DE (1) | DE2458608B2 (en) |
| ES (1) | ES432723A1 (en) |
| FR (1) | FR2254765A1 (en) |
| GB (1) | GB1485443A (en) |
| IT (1) | IT1026700B (en) |
| SE (1) | SE404213B (en) |
-
1974
- 1974-08-27 CA CA207,937A patent/CA1044887A/en not_active Expired
- 1974-10-25 GB GB46302/74A patent/GB1485443A/en not_active Expired
- 1974-11-27 FR FR7438802A patent/FR2254765A1/fr not_active Withdrawn
- 1974-11-27 BR BR9910/74A patent/BR7409910A/en unknown
- 1974-12-02 IT IT30065/74A patent/IT1026700B/en active
- 1974-12-05 JP JP49138911A patent/JPS5091869A/ja active Pending
- 1974-12-09 SE SE7415353A patent/SE404213B/en unknown
- 1974-12-09 ES ES432723A patent/ES432723A1/en not_active Expired
- 1974-12-11 DE DE2458608A patent/DE2458608B2/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| BR7409910A (en) | 1976-05-25 |
| DE2458608B2 (en) | 1980-05-08 |
| SE404213B (en) | 1978-09-25 |
| DE2458608A1 (en) | 1975-06-19 |
| ES432723A1 (en) | 1976-12-01 |
| SE7415353L (en) | 1975-06-16 |
| IT1026700B (en) | 1978-10-20 |
| JPS5091869A (en) | 1975-07-22 |
| FR2254765A1 (en) | 1975-07-11 |
| GB1485443A (en) | 1977-09-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3895449A (en) | Air impingement system | |
| US4218833A (en) | Float treatment apparatus | |
| US4185399A (en) | Doctor blade, drying or sealing assembly | |
| US4274210A (en) | Gas nozzle for use in treating material webs | |
| FI62571C (en) | ANORDNING VID FLERCYLINDERTORK I EN PAPPERSMASKIN | |
| FI76142B (en) | FICKVENTILATIONSFOERFARANDE OCH -ANORDNING I EN PAPPERSMASKINS MAONGCYLINDERTORK. | |
| US4271601A (en) | Web dryer operating on the air float principle | |
| US7975402B2 (en) | Nozzle insert for a Yankee impingement hood | |
| US3936953A (en) | Air impingement system | |
| US3230636A (en) | Heat transfer method and means | |
| JP3755829B2 (en) | Combined air bar and hall bar floating dryer | |
| US5331749A (en) | Multi-functional nozzle blow box | |
| US5074278A (en) | Pocket ventilator | |
| CA1044887A (en) | Web dryer with graded apertures | |
| EP0051055B1 (en) | Apparatus for ventilating cylinder pockets in a cylinder dryer | |
| US3995375A (en) | Discharge and draw-off device for driers of material webs | |
| US3473238A (en) | Rotary cylinder dryer | |
| US6442864B2 (en) | Thermal equalizer | |
| US6094838A (en) | Curl and profile correction with high velocity hoods | |
| US4186496A (en) | Web drier section | |
| CA1036348A (en) | Yankee dryer with hood aperture ratio | |
| CA1093814A (en) | Web drier section | |
| KR800001051Y1 (en) | Hot air injection type dryer with holes | |
| CA1044459A (en) | Doctor blade, drying or sealing assembly | |
| US3356133A (en) | Cooled sheave assembly, particularly for wire enamelling apparatus |