CA1315974C - Positive pressure web floater dryer with parallel flow - Google Patents
Positive pressure web floater dryer with parallel flowInfo
- Publication number
- CA1315974C CA1315974C CA000590543A CA590543A CA1315974C CA 1315974 C CA1315974 C CA 1315974C CA 000590543 A CA000590543 A CA 000590543A CA 590543 A CA590543 A CA 590543A CA 1315974 C CA1315974 C CA 1315974C
- Authority
- CA
- Canada
- Prior art keywords
- web
- nozzle
- length
- base plate
- nozzles
- 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 - Fee Related
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
Abstract
ABSTRACT OF THE DISCLOSURE
A nozzle assembly for a web dryer is described. The nozzle assembly includes (a) an elongated plenum chamber defined by a base plate, upstream and downstream vertical parallel side plates, and end closure plates, (b) a flat pressure plate adapted to form a gas flow zone with a moving web, (c) a primary jet of the air foil Coanda type disposed at the upstream of the pressure plate continuously directing gas downstream along the face of the plate, and (d) a single secondary jet of the impingement type disposed at the generally right angled downstream terminus of the pressure plate to continuously direct gas initially substantially perpendicularly to the web and to gas flowing downstream along the gas flow zone. A modified double slot nozzle is used, a proper distance is maintained between adjacent nozzles, and the spacing of the slots within a given nozzle is optimized. Each nozzle on an upper row is between two nozzles on a bottom row of the web with no more than 12.5 mm overlap.
A nozzle assembly for a web dryer is described. The nozzle assembly includes (a) an elongated plenum chamber defined by a base plate, upstream and downstream vertical parallel side plates, and end closure plates, (b) a flat pressure plate adapted to form a gas flow zone with a moving web, (c) a primary jet of the air foil Coanda type disposed at the upstream of the pressure plate continuously directing gas downstream along the face of the plate, and (d) a single secondary jet of the impingement type disposed at the generally right angled downstream terminus of the pressure plate to continuously direct gas initially substantially perpendicularly to the web and to gas flowing downstream along the gas flow zone. A modified double slot nozzle is used, a proper distance is maintained between adjacent nozzles, and the spacing of the slots within a given nozzle is optimized. Each nozzle on an upper row is between two nozzles on a bottom row of the web with no more than 12.5 mm overlap.
Description
131~ 9 7 ~
POSITIVE PRES:,URE WE13 FLOAT~R DRY~ _ F~ACKGROUND OF THE INVFNTION
This inventivn relates to web dryers which are used in the manufacture of coa~ed paper, film and foil and related processes such as printing.
Ploater dryer3 are preferred for many web drylng processes ' because they permit the web to be transported on a cushion of heated air such ~h~t it has no physical contact with any solid member such as a conveyer or roll until its surface is dry or cured. The alr cushion provldes support while drying the web.
Furthermore, the absence of mechanical support memb~rs for the web allows the hea~ for drying to be applied intimately and unlformly to both sides of the web simultaneously. In this way drying lntensity can be very high if desired.
., . ' ~
The technology o~ ~loater drying has experlenced substantial development in the past twenty years and certain lmportant and deslrable features have been discovered and quantified. Two ba~ic types of nozzles have evolved, a single slot nozzle and a clouble slot impingement nozzle.
.
:
One of these rlozzles, the single slot, nozzle is descrlbed in U.S. Paten~ 3,5~.7,177 and ls illustrated in Fig. 1 A
. , - . -plurality of these nozzles arranged in~staggered formation on each side of the web con~titute a ~ryer. Heated air emerges from a singl~e slot and is turned around a curved surface to fIow parallel to tlle~traYel dlrectlon of the web. The nozzle - . ~ :
:, ,:
.
POSITIVE PRES:,URE WE13 FLOAT~R DRY~ _ F~ACKGROUND OF THE INVFNTION
This inventivn relates to web dryers which are used in the manufacture of coa~ed paper, film and foil and related processes such as printing.
Ploater dryer3 are preferred for many web drylng processes ' because they permit the web to be transported on a cushion of heated air such ~h~t it has no physical contact with any solid member such as a conveyer or roll until its surface is dry or cured. The alr cushion provldes support while drying the web.
Furthermore, the absence of mechanical support memb~rs for the web allows the hea~ for drying to be applied intimately and unlformly to both sides of the web simultaneously. In this way drying lntensity can be very high if desired.
., . ' ~
The technology o~ ~loater drying has experlenced substantial development in the past twenty years and certain lmportant and deslrable features have been discovered and quantified. Two ba~ic types of nozzles have evolved, a single slot nozzle and a clouble slot impingement nozzle.
.
:
One of these rlozzles, the single slot, nozzle is descrlbed in U.S. Paten~ 3,5~.7,177 and ls illustrated in Fig. 1 A
. , - . -plurality of these nozzles arranged in~staggered formation on each side of the web con~titute a ~ryer. Heated air emerges from a singl~e slot and is turned around a curved surface to fIow parallel to tlle~traYel dlrectlon of the web. The nozzle - . ~ :
:, ,:
.
2 ~3~ ~7~
~reates what ls known as the "Coanda effect" wherein the air does not implnge ~irectly into the web and is constrained between the weh and a parallel plate for a nominal distance ~50-150mm) to achieve high heat transfer. The heated air flow then continues for a similar distance beyond the trailing edge of the plate as a free wall ~et parallel to and adjacent to the web. Finally, as the air flow approaches the next noz~le in seguence, it turns and flows away in the space bet~ieen the nozzles.
This single slot nozzle which creates the "Coanda effect"
has seen extensive use worldwlde. The single slot nozzle provides high heat transfer which is uniform across the machine and fairly unlform ln the direction of web movement. Because of the parallel direction of the air flow and web movement, the heat transfer can be further augmented by passing the web through the dryer such that it flows counterflow to the direction o~ the air. The local uniformlty of heat transfer and conse~uent dr~lny has beneficial effects to the quality of certain products aJld coatings dried on this type of machine.
Slnce alr flows aro unidirectional, interacting streams oE air are avoided which has benefits to cross-machine flow uniformity and web stabllity.
With the sin~le slot nozzle, there is no posltive pressure pad between the p,~rallel plate and the web. As a result, the web travels throu~Jh the dryer in a flat plane at a distance from the plate of about 2.5 times the wldth of the slot.
Accurate alignment and parallelism of the nozzles is required to avoid web flu~ter at low tensions. At high tensions, webs have a tendency to curI at the edges and develop longitudinal wrinkles. When thi.s occurs the possibility of contact between `~ ' .
....
~reates what ls known as the "Coanda effect" wherein the air does not implnge ~irectly into the web and is constrained between the weh and a parallel plate for a nominal distance ~50-150mm) to achieve high heat transfer. The heated air flow then continues for a similar distance beyond the trailing edge of the plate as a free wall ~et parallel to and adjacent to the web. Finally, as the air flow approaches the next noz~le in seguence, it turns and flows away in the space bet~ieen the nozzles.
This single slot nozzle which creates the "Coanda effect"
has seen extensive use worldwlde. The single slot nozzle provides high heat transfer which is uniform across the machine and fairly unlform ln the direction of web movement. Because of the parallel direction of the air flow and web movement, the heat transfer can be further augmented by passing the web through the dryer such that it flows counterflow to the direction o~ the air. The local uniformlty of heat transfer and conse~uent dr~lny has beneficial effects to the quality of certain products aJld coatings dried on this type of machine.
Slnce alr flows aro unidirectional, interacting streams oE air are avoided which has benefits to cross-machine flow uniformity and web stabllity.
With the sin~le slot nozzle, there is no posltive pressure pad between the p,~rallel plate and the web. As a result, the web travels throu~Jh the dryer in a flat plane at a distance from the plate of about 2.5 times the wldth of the slot.
Accurate alignment and parallelism of the nozzles is required to avoid web flu~ter at low tensions. At high tensions, webs have a tendency to curI at the edges and develop longitudinal wrinkles. When thi.s occurs the possibility of contact between `~ ' .
....
3 ~33.~
the web and nozzles ls hlgh. Thus, thls type of nozzle has llmitations in some kinds of drying situatlons.
The principal alternatlve type of nozzle, the double slot lmpingement nozzle, ls descrlbed ln U.S. Patent 3,873,013 and ls lllustrated ln Fi~. 2. Thls double slot lmplngement nozzle lncorporates two slots whlch blow air normal to the we~. In this manner, a pocket of alr at positive pressure is entrapped between the ~ets. A ma~or portlon of the air flow from the ~ets impinges aga.inst the web and flows away from both slots on the nozæle. Some of this air rebounds dlrectly away from the web and some flows aLong the web untll lt meets the corresponding stream from the ad~acent nozzle. Heat transfer with this double slot nozzle is comparable on average to the parallel flow type of nozzle under the same fan power conditions; however, there is much variabllity in heat transfer in the machlne direction. In the lmmedlate vlclnlty of the lmpinglng ~ets, heat transfer ls very high, but between each ~et in the pair on the nozzle and in the region between the nozzles, lt is quite low. For sensltive products, the hi~h impingement heat ~ransfer of this nozzle can cause quality problems. Interaction of the exlting streams oE alr between the nozzles can lntroduce web lnstabillty lf the nozzles are placed too close together.
A very lmportant feature of this double slot lmpingement type of nozzle ls the posltlve pressure pad formed between the mpingement jets. Not only does thls tend to keep the web away from spurious contnct vith the nozzle, the staggered arrangement on each side of the web imParts an undulating motion to the web in the machine direction somethln~ like a slne wave. This corrugatlon effect gives the web some physical ' `' .
the web and nozzles ls hlgh. Thus, thls type of nozzle has llmitations in some kinds of drying situatlons.
The principal alternatlve type of nozzle, the double slot lmpingement nozzle, ls descrlbed ln U.S. Patent 3,873,013 and ls lllustrated ln Fi~. 2. Thls double slot lmplngement nozzle lncorporates two slots whlch blow air normal to the we~. In this manner, a pocket of alr at positive pressure is entrapped between the ~ets. A ma~or portlon of the air flow from the ~ets impinges aga.inst the web and flows away from both slots on the nozæle. Some of this air rebounds dlrectly away from the web and some flows aLong the web untll lt meets the corresponding stream from the ad~acent nozzle. Heat transfer with this double slot nozzle is comparable on average to the parallel flow type of nozzle under the same fan power conditions; however, there is much variabllity in heat transfer in the machlne direction. In the lmmedlate vlclnlty of the lmpinglng ~ets, heat transfer ls very high, but between each ~et in the pair on the nozzle and in the region between the nozzles, lt is quite low. For sensltive products, the hi~h impingement heat ~ransfer of this nozzle can cause quality problems. Interaction of the exlting streams oE alr between the nozzles can lntroduce web lnstabillty lf the nozzles are placed too close together.
A very lmportant feature of this double slot lmpingement type of nozzle ls the posltlve pressure pad formed between the mpingement jets. Not only does thls tend to keep the web away from spurious contnct vith the nozzle, the staggered arrangement on each side of the web imParts an undulating motion to the web in the machine direction somethln~ like a slne wave. This corrugatlon effect gives the web some physical ' `' .
4 11 3 ~
stiffness in the cross-machine direction which strongly resists tendencies to curl at the edges and to form wrlnkles. This important feature o~ the double slot impingement nozzle also renders it less sensitlve to dimenslonal accuracy ln the posltloning and allgnment of the nozzles.
The pattern of pressure pads formed by the double slot impingement nozzle as arranged ln a typical dryer ls illustrated ln Fig. 3. It ls characterized by the large spl~es opposite the slots whlch are caused by stagnatlon of the alr veloclty at the web, a generally uniform elevated pressure between the splkes and a reglon to each side of the pressure pad where ~here ls essentlally no posltlve pressure.
The effect on the web of such a pattern of pressure pads is lllustrated ln Flg. ~ whlch also shows the local relatlonship between the pressure, the web tenslon and the radlus of curvature of the web. For a local lncremental region of constant pressure, the following equation applles:
R = T
P
where R ls the radlus of curvature, T ls the web tension and P
is the local pressure applled to the web. If P is zero, the radius of curvature i.s infinite which mathematically indicates that the sheet wlll be flat. If P i~ constant, the radius of curvature is a circular arc.
Flg. 5, Flg. 6, and Flg. 7 show the varlatlon ln web curvature for thre~ dlfferent nozzle assemblles. Flg. 5 shows that the slngle slot nozzle causes the web to form a ~agged undulation wave. Although the web undulates it has no curva~ure and therefore can curl locally. ~ double impingement .~ .
, nozzle applies pressure to the web over a finite distance b as shown ln Flg, 6. Thus, lgnoring the local effec~ of the splkes shown in Fig. 3, the generally constant pressure region will produc~ circular arc curvature over the pressure region wlth generally flaC segments between them. This is a much better arrangement than is shown ln Fig. 5 but the segments of the web having no curvature are still sub~ect to local curl.
Fig. 7 shows that lf the pressure region is made to be equal to half the undulation wave length, curvature i~ obtained throughout the len~th of the web. This is the objective condition for maximum resistance to curl. To achieve this wlth the double impingement nozzle requires that they be spaced on a pltch that is exac~ly twlce the nozzle length dimension in the direction of the web movement. As discussed earlier, double impingement nozzles cannot be placed close together because of flow instabilities associated wlth the exltlng flows meeting between the nozzles.
Another nozzle ~or obtainin~ a posi~ive pressure pad with a parallel flow is ~escrlbed in U.S. Patent ~ ,757. Thls nozzle modiiies the basic Coanda type parallel unidirectional flow nozzle ~Flg. 1) to produce a posltive pressure pad without implngement of air against the web. This nozzle is herein termed the modlfied double slot nozzle. Extensive experimental work has shown tha~ this technique can produce a pressure pad that is longer in the machine direction than the nozzle. It ha~s no high spikes of pressure and can be configured, through proper selection of ~he design dimensions, to yield a web undulatlon pattern that maintains continuous curvature along t~e entire machino.
`
': ' ~ 3 ~ f1 Thls modified double slot nozzle can provide pressure pad forces that are greater than those obtainable with the double lmplngement noææle at the same condltlons of flow and heat transfer. Furthermore, it retains the flow uniformity advantages o~ the unidirectional parallel flow nozzle and lmproves upon its heat transfex unlformity. The dlmensional relationships obtained from the experlmental investigation constitute the subject of the present invention.
.
The pressure level o~ the pressure pad shown in Fig. 9 is governed by the noz.æl.e spacing which influences the kinetic pressure of the carry-over flow 5 and by the relative sizes of the primary ~et 1 and the secondary ~et 6. Processing difficulties may arise where there is a low or no pressure region whlch will allow the web to curl at the edges or to form wrinkles. The problem is further complicated by the fact that the nozzle spacing in a dryer will vary dependlng on the maximum drying rat:e required and the optimizatlon of cost. In accordance with the present inv~entlon, the modified double slot nozzle is used to maximum advantage by optimizing the relationships of the the spacin~ between the nozzles and the nozæle lengths in thu machine direction.
.~
If the size of secondary ~et on the nozzle is too large in relation to the size of the primary ~et, the Coanda effect will break down and the nozzle will become a skewed double impingement nozzle. As the secondary ~et decreases in slze, ; the pressure pad becomes weaker until at a secondary jet size of zero, the nozzle degenerates to a conventional parallel flow Coanda nozzle as shown in Fig. 1.
. , ., ~ : , :
' .
, 1 3 ~ 71727-50 SUMMARY OF INVENTION
In accordance with the present invention it has been found that the disadvantages of the nozzles employed in the prior art for web drying can be significantly reduced by utilizing a modified double slot nozzle and maintaining a proper distance between nozzles and by optimizing the spacing of the slots within a given nozzle.
Accordingly, the present invention-provides a dryer assembly for drying a moving flexible continuous web of material, said assembly including a plurality of nozzle assemblies, each nozzle assembly comprising: (a) an elongated plenum chamber defined by a base plate, upstream and downstream vertical parallel side plates, and end closure plates; (b) a flat pressure plate adapted to form a gas flow zone with a moving web; (c) a primary jet of the airfoil Coanda type disposed at the upstream of the pressure plate continuously directing gas downstream along the face of th~ plate; (d) a s:ingle secondary jet of the impinge-ment type disposed at the yenerally right angled downstream terminus of the pressure plate to continuously direct gas initially substantially perpendicularly to the web and to gas flowing downstream along the gas flow zone, wherein the preferred range of distance between nozzles has been found to be a continuum defined by the following points: i) 75-125 mm where the length of the base plate is 50 mm; ii) 125-200 mm where the length of the base plate is 75 mm; iii~ 175-275 mm where the length of the base plate is 100 mm; iv) 225-325 mm where the :~ length of the base plate is 125 mm; v) 275~350 mm where the .~ .
, ,, . - -., ~ i .
.. . . .
-:' -~ 7a ~ 3 ~ r 71727-50 length of the base plate is 150 mm; vi) 325-375 mm where the length of the base plate is 175 mm; vii) 375-400 mm where the length of the base plate is 200 mm; or viii) 425 mm where the length o the base plate is 225 mm; for each row of nozzles parallel to the web, where each nozzle on the upper row is between two nozzles on the bottom row of the web, with no more than 12.5 mm overlap. The optimum slot width of the secondary jet has been found to be in the range of 35% to 45-- of the slot width of the primary jet, with 40% to 45% being preferred.
Accordingly, it is an object of the present invention to provide a system for drying a web which yields the most effective means of controlling sheet edge curl and wrinkling.
~ .
:, ~', :'' , 8 1 3 ~
The advantages of the present inventlon will become apparent from the fo].lowing description taken in conjunction with the drawing.
BRIEF DESCRIPTION OF T~IE FIGURES
Fig. 1 ls a diagrammatic view showing a prior art dryer employing the slngle slot nozzle;
Pig. 2 ls a dlagrammatic vlew showlng a prior art dryer assembly employin~ ~he double slot impingement nozzle;
Fig. 3 is a graphic representation o~ a pattern of pressure pads formed by an arrangement of typlcal double lmpingement nozzles of the type shown ln Fig. 2, as arranged ln a typical dryer;
Fig. 4 ls a dlagrammatlc view showing the e~fect on the web of the pattern of pressure pads formed by the double implngement nozzles Oe the type shown ln Flg. 2, as arranged in a typlcal dryer;
Fig. S is a diagrammatic vlew showlng the ~agged undulatlon wave formed by the slngle slot nozzles of the ty~e shown ln Flg. 1, as used in a typical dryer;
.
Fig. 6 is a diagrammatic view showing the wave curvature of~the web when the double slot lmpin~ement nozzle of the type ~ ~ shown in ~ig. 2 is used ln a typical dryer;
,' : ~
~ Flg. 7 is a cl~a~rammatic vlew showing the wave curv~ture , . :
, 9 ~ 3 ~ 71727-50 of the web where the pressure region is made to be equal to half the undulation wave length;
Fig. 8 is a sectional view showing a prior art modified double slot nozzle;
Fig. 9 is a diagrammatic representation showing the modified double slot nozzle of the type shown in Fig. 8 and the shape of a typical pressure pad created by that nozzle;
Figs. lO(a)-l~(c) are dia~rammatic views showing that the length of the primary portion of the pressure pad is directly proportional to the length of the pressure plate for any practical nozzle dimensions;
Fig. lO(a) shows the length of the pressure pad with a rela~ively short pressure plate;
Fig. lO(b) shows the length of the pressure pad with a longer pressure plate; and Figure lO(c) shows the length of the pressure pad with an even longer pressure plate;
Figures ll(a)-ll(c) are diagrammatic views showing that the magnitude of the secondary portion oE the pressure pad is inversely proportional to the nozzle spacing, but its length does not significantly change;
Fig. ll(a) shows the magni-tude of the secondary portion of the pressure pad when the nozzles are close together;
Fig. ll(b) shows the magnitude of the secondary portion of the pressure pad when the nozzles are ~arther apart; and Fig. ll(c) shows the magnitude of the secondary portion of the pressure pad when the nozzles are even farther apart.
9a 71727-50 Fig. 12 is a diagrammatic vie~l showing the modified double slot nozzles of the type shown in Fig. 8 arranged in a typical dryer a-t a distance apart such that there is no danger that the web will rub against the nozzles;
Fig. 13 is a diagrammatic view of the modified double slot nozzles of the type shown in Fig. 8 arranged so close together in a typical dryer that there is a danger that the web will rub against the nozzles; and Fig. 14 is a graph defining the preferred range of dimensions for the modified double slot nozzle of the type shown in Fig. 8 to yield optimal condition of web curvature Eor curl and wrinkle resistance.
' :;
~ .
~. :
,: :
: . . , ~, ~ ' ' ~ .
lo ~ 3 ~
~ PTION OF THE PR~FERRED EMBODIMENT
At the outset the invention is described in its broadest overall asp~cts wlth a more detailed descrlptlon followlng.
The broadest overall aspects o~ the invention involve 1) optimizing the dlstance between two modified double slot nozzles and 2) modifying the relationship between the opening of the primary slo~ and the secondary slot on a modified double slot nozzle to produ~e a more uniform pressure pad throughou~ a web drying assembly.
The invention utilizes the modified double slot nozzle as shown in U.S. Pa~ent 4,414,757. A sectional view of that nozzle is shown in Fig. 8 and generally comprises an elongated plenum chamber 15, upstream and downstream vertical side pla~es 16, and a base plate 21. The upper portion of the plenum chamber 15 is de~ined by a pair of L-shaped angle members 17 having vertical legs 1~ ~ttached to side plates 16 and horlzontal legs 19 which extend inwardly toward each other to form an elongated gas discharge 510t 20 ~or the plenum. The length of the nozzle is the length of the base plate 27.
A U-shaped assembly 21 is mounted between the ou~er wall o~ the chamber 15 ~ormed by the horizontal legs 19 and the web 4. The plate assembly comprises a vertical upstream wall 22, a vertical downstream wall 23, and a horizontal flat pressure plate 3 joining the walls. The upstream corner 24 ~oining wall 22 and pressure plate 3 is curved, and the downstream corner 25 joinlng 23 and pxessure plate 3 is at a relatively substantlally rlgh~ angle, -:
' .
.
1 3 ~ ~ ~ 7 1~
ll The upstream slde plate 16 extends vertically beyond upstream leg 19 to merge into inwardlY inclined foil plate 28.
The space between the end of the inwardly inclined foil plate 28 and the covered corner 24 forms the prlmary gas dlscharge slot 29.
A secondary slot is formed at the downstream end of the assembly by extending the downstream plenum side plate 16 beyond downstream leg 19 to merge into an inwardly inclined plate 26 which terminates ~ust short o~ pressure plate 3.
The gas flow characteristics of the noæzle are illustrated in Fig. 9. A stream of air 1 flows from the primary jet and runs by means of the Coanda Effect to ~low into the space 2 between the pressure plate 3 and the web 4. In addi~ion, a portion 5 of the resldual flow from the preceding nozzle joins the primary ~et flow to form the total flow stream in region 2.
At the trailln~ ed~3e of the pressure plate 3, a secondary nozzle 6 aims a jet 7 essentially normal to the web and at the same velocity as the primary je~.
A portlon of the momsntum in the flow stream coming from the prlmary ~et 1 and the carry-over flow 5 ls converted into pressure as lt turns the momentum vector 8 of the secondary ~et 7 from a direction perpendicular to the web to a direction parallel to the web 9. Because pressure is a scaler quantlty, it acts in the entire region between the primary and secondary ~ets. Thus this no~zle creates a pressure pad by ralsing the static pressure in the parallel flow and not by impinging flow a~ the web.
, : :
, ~ . ' . , ~ "'',"; ' .
12 ~ 3 ~
The shape of the pressure pad for a slngle no~zle is identifled by 10 in Flg. 9. In a sequential array of nozzles, a small fraction of ~he parallel flow from the preceding nozzle 11 enters the region 2 but most of it 12 is caused to turn and flow away between t~le nozzles 13. What actually happens is that the residual vel.ocity o~ the parallel flow 12 is converted into pressure. This pressure is then converted into the velocity perpendicular to the web represented by the exhaust flow 13. In the other directlon, this stagnation pressure creates an added component to the pressure pad 14.
. ~
The length of the pressure pad in the direction of web travel is governed by the length of the pressure plate 3 and by the spaclng between the nozzles. Since the pressure wave ~ormed by the momentum d.irection change of the secondary jet travels upstream at the speed oE sound, the length of the primary portion 10 of the pressure pad will be dlrectly proportional to the length o~ the pressure plate 3 for any practlcal nozzle dimenslons. This effect is illustrated in Fig. 10. The magn.ttude of the secondary portion of the pressure pad will be inversely proportional to the nozzle spacing but lts len~h will not signi~icantly change. At large spacings, this secoll~lary portion 1~ becomes so wea~ that it contributes little to the curvature of the web. This effect is illustrated in Fig. 11. At close spacing the pressure pad provides improved coverage of the web. In the limit when the nozzles above and below the web hegin to overlap, there is insufficient physical space to accommodate the undulation as shown ln Fig. 12. Thus, the limitations illustrated in these last two figures define the practical limits of nozzle spacing related to nozzle machine direction length. These can be summarlzed as shown in Fi~. 13 which deflnes the preferred ~--:
:1 3 ~
rang~ o~ dlmension~ ~or thl~ nozzl4 to yield optlmAl condltion~
o~ web curvature ~or curl and wrinkle resl~tance.
~ o ensure that the th~ Coanda e~ect does not brea~ down as where the secondary ~et 15 too larga, or that the pressure pad does not become too wQak, a~ where the secondary ~et 1~ too small,the slot width ~or the secondAry ~et should ldeally lle ln the ranye Or 35% ~o 45~ G~ thQ 810t wldth Or the prlmary ~et, wlth 40% to ~ b~ln~ ~rarerre~.
.
.
.; ~
" . .
,, ' ~
.
stiffness in the cross-machine direction which strongly resists tendencies to curl at the edges and to form wrlnkles. This important feature o~ the double slot impingement nozzle also renders it less sensitlve to dimenslonal accuracy ln the posltloning and allgnment of the nozzles.
The pattern of pressure pads formed by the double slot impingement nozzle as arranged ln a typical dryer ls illustrated ln Fig. 3. It ls characterized by the large spl~es opposite the slots whlch are caused by stagnatlon of the alr veloclty at the web, a generally uniform elevated pressure between the splkes and a reglon to each side of the pressure pad where ~here ls essentlally no posltlve pressure.
The effect on the web of such a pattern of pressure pads is lllustrated ln Flg. ~ whlch also shows the local relatlonship between the pressure, the web tenslon and the radlus of curvature of the web. For a local lncremental region of constant pressure, the following equation applles:
R = T
P
where R ls the radlus of curvature, T ls the web tension and P
is the local pressure applled to the web. If P is zero, the radius of curvature i.s infinite which mathematically indicates that the sheet wlll be flat. If P i~ constant, the radius of curvature is a circular arc.
Flg. 5, Flg. 6, and Flg. 7 show the varlatlon ln web curvature for thre~ dlfferent nozzle assemblles. Flg. 5 shows that the slngle slot nozzle causes the web to form a ~agged undulation wave. Although the web undulates it has no curva~ure and therefore can curl locally. ~ double impingement .~ .
, nozzle applies pressure to the web over a finite distance b as shown ln Flg, 6. Thus, lgnoring the local effec~ of the splkes shown in Fig. 3, the generally constant pressure region will produc~ circular arc curvature over the pressure region wlth generally flaC segments between them. This is a much better arrangement than is shown ln Fig. 5 but the segments of the web having no curvature are still sub~ect to local curl.
Fig. 7 shows that lf the pressure region is made to be equal to half the undulation wave length, curvature i~ obtained throughout the len~th of the web. This is the objective condition for maximum resistance to curl. To achieve this wlth the double impingement nozzle requires that they be spaced on a pltch that is exac~ly twlce the nozzle length dimension in the direction of the web movement. As discussed earlier, double impingement nozzles cannot be placed close together because of flow instabilities associated wlth the exltlng flows meeting between the nozzles.
Another nozzle ~or obtainin~ a posi~ive pressure pad with a parallel flow is ~escrlbed in U.S. Patent ~ ,757. Thls nozzle modiiies the basic Coanda type parallel unidirectional flow nozzle ~Flg. 1) to produce a posltive pressure pad without implngement of air against the web. This nozzle is herein termed the modlfied double slot nozzle. Extensive experimental work has shown tha~ this technique can produce a pressure pad that is longer in the machine direction than the nozzle. It ha~s no high spikes of pressure and can be configured, through proper selection of ~he design dimensions, to yield a web undulatlon pattern that maintains continuous curvature along t~e entire machino.
`
': ' ~ 3 ~ f1 Thls modified double slot nozzle can provide pressure pad forces that are greater than those obtainable with the double lmplngement noææle at the same condltlons of flow and heat transfer. Furthermore, it retains the flow uniformity advantages o~ the unidirectional parallel flow nozzle and lmproves upon its heat transfex unlformity. The dlmensional relationships obtained from the experlmental investigation constitute the subject of the present invention.
.
The pressure level o~ the pressure pad shown in Fig. 9 is governed by the noz.æl.e spacing which influences the kinetic pressure of the carry-over flow 5 and by the relative sizes of the primary ~et 1 and the secondary ~et 6. Processing difficulties may arise where there is a low or no pressure region whlch will allow the web to curl at the edges or to form wrinkles. The problem is further complicated by the fact that the nozzle spacing in a dryer will vary dependlng on the maximum drying rat:e required and the optimizatlon of cost. In accordance with the present inv~entlon, the modified double slot nozzle is used to maximum advantage by optimizing the relationships of the the spacin~ between the nozzles and the nozæle lengths in thu machine direction.
.~
If the size of secondary ~et on the nozzle is too large in relation to the size of the primary ~et, the Coanda effect will break down and the nozzle will become a skewed double impingement nozzle. As the secondary ~et decreases in slze, ; the pressure pad becomes weaker until at a secondary jet size of zero, the nozzle degenerates to a conventional parallel flow Coanda nozzle as shown in Fig. 1.
. , ., ~ : , :
' .
, 1 3 ~ 71727-50 SUMMARY OF INVENTION
In accordance with the present invention it has been found that the disadvantages of the nozzles employed in the prior art for web drying can be significantly reduced by utilizing a modified double slot nozzle and maintaining a proper distance between nozzles and by optimizing the spacing of the slots within a given nozzle.
Accordingly, the present invention-provides a dryer assembly for drying a moving flexible continuous web of material, said assembly including a plurality of nozzle assemblies, each nozzle assembly comprising: (a) an elongated plenum chamber defined by a base plate, upstream and downstream vertical parallel side plates, and end closure plates; (b) a flat pressure plate adapted to form a gas flow zone with a moving web; (c) a primary jet of the airfoil Coanda type disposed at the upstream of the pressure plate continuously directing gas downstream along the face of th~ plate; (d) a s:ingle secondary jet of the impinge-ment type disposed at the yenerally right angled downstream terminus of the pressure plate to continuously direct gas initially substantially perpendicularly to the web and to gas flowing downstream along the gas flow zone, wherein the preferred range of distance between nozzles has been found to be a continuum defined by the following points: i) 75-125 mm where the length of the base plate is 50 mm; ii) 125-200 mm where the length of the base plate is 75 mm; iii~ 175-275 mm where the length of the base plate is 100 mm; iv) 225-325 mm where the :~ length of the base plate is 125 mm; v) 275~350 mm where the .~ .
, ,, . - -., ~ i .
.. . . .
-:' -~ 7a ~ 3 ~ r 71727-50 length of the base plate is 150 mm; vi) 325-375 mm where the length of the base plate is 175 mm; vii) 375-400 mm where the length of the base plate is 200 mm; or viii) 425 mm where the length o the base plate is 225 mm; for each row of nozzles parallel to the web, where each nozzle on the upper row is between two nozzles on the bottom row of the web, with no more than 12.5 mm overlap. The optimum slot width of the secondary jet has been found to be in the range of 35% to 45-- of the slot width of the primary jet, with 40% to 45% being preferred.
Accordingly, it is an object of the present invention to provide a system for drying a web which yields the most effective means of controlling sheet edge curl and wrinkling.
~ .
:, ~', :'' , 8 1 3 ~
The advantages of the present inventlon will become apparent from the fo].lowing description taken in conjunction with the drawing.
BRIEF DESCRIPTION OF T~IE FIGURES
Fig. 1 ls a diagrammatic view showing a prior art dryer employing the slngle slot nozzle;
Pig. 2 ls a dlagrammatic vlew showlng a prior art dryer assembly employin~ ~he double slot impingement nozzle;
Fig. 3 is a graphic representation o~ a pattern of pressure pads formed by an arrangement of typlcal double lmpingement nozzles of the type shown ln Fig. 2, as arranged ln a typical dryer;
Fig. 4 ls a dlagrammatlc view showing the e~fect on the web of the pattern of pressure pads formed by the double implngement nozzles Oe the type shown ln Flg. 2, as arranged in a typlcal dryer;
Fig. S is a diagrammatic vlew showlng the ~agged undulatlon wave formed by the slngle slot nozzles of the ty~e shown ln Flg. 1, as used in a typical dryer;
.
Fig. 6 is a diagrammatic view showing the wave curvature of~the web when the double slot lmpin~ement nozzle of the type ~ ~ shown in ~ig. 2 is used ln a typical dryer;
,' : ~
~ Flg. 7 is a cl~a~rammatic vlew showing the wave curv~ture , . :
, 9 ~ 3 ~ 71727-50 of the web where the pressure region is made to be equal to half the undulation wave length;
Fig. 8 is a sectional view showing a prior art modified double slot nozzle;
Fig. 9 is a diagrammatic representation showing the modified double slot nozzle of the type shown in Fig. 8 and the shape of a typical pressure pad created by that nozzle;
Figs. lO(a)-l~(c) are dia~rammatic views showing that the length of the primary portion of the pressure pad is directly proportional to the length of the pressure plate for any practical nozzle dimensions;
Fig. lO(a) shows the length of the pressure pad with a rela~ively short pressure plate;
Fig. lO(b) shows the length of the pressure pad with a longer pressure plate; and Figure lO(c) shows the length of the pressure pad with an even longer pressure plate;
Figures ll(a)-ll(c) are diagrammatic views showing that the magnitude of the secondary portion oE the pressure pad is inversely proportional to the nozzle spacing, but its length does not significantly change;
Fig. ll(a) shows the magni-tude of the secondary portion of the pressure pad when the nozzles are close together;
Fig. ll(b) shows the magnitude of the secondary portion of the pressure pad when the nozzles are ~arther apart; and Fig. ll(c) shows the magnitude of the secondary portion of the pressure pad when the nozzles are even farther apart.
9a 71727-50 Fig. 12 is a diagrammatic vie~l showing the modified double slot nozzles of the type shown in Fig. 8 arranged in a typical dryer a-t a distance apart such that there is no danger that the web will rub against the nozzles;
Fig. 13 is a diagrammatic view of the modified double slot nozzles of the type shown in Fig. 8 arranged so close together in a typical dryer that there is a danger that the web will rub against the nozzles; and Fig. 14 is a graph defining the preferred range of dimensions for the modified double slot nozzle of the type shown in Fig. 8 to yield optimal condition of web curvature Eor curl and wrinkle resistance.
' :;
~ .
~. :
,: :
: . . , ~, ~ ' ' ~ .
lo ~ 3 ~
~ PTION OF THE PR~FERRED EMBODIMENT
At the outset the invention is described in its broadest overall asp~cts wlth a more detailed descrlptlon followlng.
The broadest overall aspects o~ the invention involve 1) optimizing the dlstance between two modified double slot nozzles and 2) modifying the relationship between the opening of the primary slo~ and the secondary slot on a modified double slot nozzle to produ~e a more uniform pressure pad throughou~ a web drying assembly.
The invention utilizes the modified double slot nozzle as shown in U.S. Pa~ent 4,414,757. A sectional view of that nozzle is shown in Fig. 8 and generally comprises an elongated plenum chamber 15, upstream and downstream vertical side pla~es 16, and a base plate 21. The upper portion of the plenum chamber 15 is de~ined by a pair of L-shaped angle members 17 having vertical legs 1~ ~ttached to side plates 16 and horlzontal legs 19 which extend inwardly toward each other to form an elongated gas discharge 510t 20 ~or the plenum. The length of the nozzle is the length of the base plate 27.
A U-shaped assembly 21 is mounted between the ou~er wall o~ the chamber 15 ~ormed by the horizontal legs 19 and the web 4. The plate assembly comprises a vertical upstream wall 22, a vertical downstream wall 23, and a horizontal flat pressure plate 3 joining the walls. The upstream corner 24 ~oining wall 22 and pressure plate 3 is curved, and the downstream corner 25 joinlng 23 and pxessure plate 3 is at a relatively substantlally rlgh~ angle, -:
' .
.
1 3 ~ ~ ~ 7 1~
ll The upstream slde plate 16 extends vertically beyond upstream leg 19 to merge into inwardlY inclined foil plate 28.
The space between the end of the inwardly inclined foil plate 28 and the covered corner 24 forms the prlmary gas dlscharge slot 29.
A secondary slot is formed at the downstream end of the assembly by extending the downstream plenum side plate 16 beyond downstream leg 19 to merge into an inwardly inclined plate 26 which terminates ~ust short o~ pressure plate 3.
The gas flow characteristics of the noæzle are illustrated in Fig. 9. A stream of air 1 flows from the primary jet and runs by means of the Coanda Effect to ~low into the space 2 between the pressure plate 3 and the web 4. In addi~ion, a portion 5 of the resldual flow from the preceding nozzle joins the primary ~et flow to form the total flow stream in region 2.
At the trailln~ ed~3e of the pressure plate 3, a secondary nozzle 6 aims a jet 7 essentially normal to the web and at the same velocity as the primary je~.
A portlon of the momsntum in the flow stream coming from the prlmary ~et 1 and the carry-over flow 5 ls converted into pressure as lt turns the momentum vector 8 of the secondary ~et 7 from a direction perpendicular to the web to a direction parallel to the web 9. Because pressure is a scaler quantlty, it acts in the entire region between the primary and secondary ~ets. Thus this no~zle creates a pressure pad by ralsing the static pressure in the parallel flow and not by impinging flow a~ the web.
, : :
, ~ . ' . , ~ "'',"; ' .
12 ~ 3 ~
The shape of the pressure pad for a slngle no~zle is identifled by 10 in Flg. 9. In a sequential array of nozzles, a small fraction of ~he parallel flow from the preceding nozzle 11 enters the region 2 but most of it 12 is caused to turn and flow away between t~le nozzles 13. What actually happens is that the residual vel.ocity o~ the parallel flow 12 is converted into pressure. This pressure is then converted into the velocity perpendicular to the web represented by the exhaust flow 13. In the other directlon, this stagnation pressure creates an added component to the pressure pad 14.
. ~
The length of the pressure pad in the direction of web travel is governed by the length of the pressure plate 3 and by the spaclng between the nozzles. Since the pressure wave ~ormed by the momentum d.irection change of the secondary jet travels upstream at the speed oE sound, the length of the primary portion 10 of the pressure pad will be dlrectly proportional to the length o~ the pressure plate 3 for any practlcal nozzle dimenslons. This effect is illustrated in Fig. 10. The magn.ttude of the secondary portion of the pressure pad will be inversely proportional to the nozzle spacing but lts len~h will not signi~icantly change. At large spacings, this secoll~lary portion 1~ becomes so wea~ that it contributes little to the curvature of the web. This effect is illustrated in Fig. 11. At close spacing the pressure pad provides improved coverage of the web. In the limit when the nozzles above and below the web hegin to overlap, there is insufficient physical space to accommodate the undulation as shown ln Fig. 12. Thus, the limitations illustrated in these last two figures define the practical limits of nozzle spacing related to nozzle machine direction length. These can be summarlzed as shown in Fi~. 13 which deflnes the preferred ~--:
:1 3 ~
rang~ o~ dlmension~ ~or thl~ nozzl4 to yield optlmAl condltion~
o~ web curvature ~or curl and wrinkle resl~tance.
~ o ensure that the th~ Coanda e~ect does not brea~ down as where the secondary ~et 15 too larga, or that the pressure pad does not become too wQak, a~ where the secondary ~et 1~ too small,the slot width ~or the secondAry ~et should ldeally lle ln the ranye Or 35% ~o 45~ G~ thQ 810t wldth Or the prlmary ~et, wlth 40% to ~ b~ln~ ~rarerre~.
.
.
.; ~
" . .
,, ' ~
.
Claims (3)
1. A dryer assembly for drying a moving flexible continuous web of material, said assembly including a plurality of nozzle assemblies, each nozzle assembly comprising:
(a) an elongated plenum chamber defined by a base plate, upstream and downstream vertical parallel side places, and end closure plates, (b) a flat pressure plate adapted to form a gas flow zone with a moving web, (c) a primary jet of the airfoil Coanda type disposed at the upstream of the pressure plate continuously directing gas downstream along the face of the plate, (d) a single secondary jet of the impingement type disposed at the generally right angled downstream terminus of the pressure plate to continuously direct gas initially substantially perpendicularly to the web and to gas flowing downstream along the gas flow zone, wherein the preferred range of distance between nozzles has been found to be a continuum defined by the following points:
i) 75-125 mm where the length of the base plate is 50 mm;
11) 125-200 mm where the length of the base plate is 75 iii) 175-275 mm where the length of the base plate is 100 mm;
iv) 225-325 mm where the length of the base plate is 125 mm;
v) 275-350 mm where the length of the base plate is 150 mm;
vi) 325-375 mm where the length of the base plate is 175 mm;
vii) 375-400 mm where the length of the base plate is 200 mm; or viii) 425 mm where the length of the base plate is 225 mm;
for each row of nozzles parallel to the web, where each nozzle on the upper row is between two nozzles on the bottom row of the web, with no more than 12.5 mm overlap.
(a) an elongated plenum chamber defined by a base plate, upstream and downstream vertical parallel side places, and end closure plates, (b) a flat pressure plate adapted to form a gas flow zone with a moving web, (c) a primary jet of the airfoil Coanda type disposed at the upstream of the pressure plate continuously directing gas downstream along the face of the plate, (d) a single secondary jet of the impingement type disposed at the generally right angled downstream terminus of the pressure plate to continuously direct gas initially substantially perpendicularly to the web and to gas flowing downstream along the gas flow zone, wherein the preferred range of distance between nozzles has been found to be a continuum defined by the following points:
i) 75-125 mm where the length of the base plate is 50 mm;
11) 125-200 mm where the length of the base plate is 75 iii) 175-275 mm where the length of the base plate is 100 mm;
iv) 225-325 mm where the length of the base plate is 125 mm;
v) 275-350 mm where the length of the base plate is 150 mm;
vi) 325-375 mm where the length of the base plate is 175 mm;
vii) 375-400 mm where the length of the base plate is 200 mm; or viii) 425 mm where the length of the base plate is 225 mm;
for each row of nozzles parallel to the web, where each nozzle on the upper row is between two nozzles on the bottom row of the web, with no more than 12.5 mm overlap.
2. The nozzle assembly according to claim 1 wherein the slot width of the secondary jet is in the range of 35% to 45%
of the slot width of the primary jet.
of the slot width of the primary jet.
3. The nozzle assembly according to claim 1 wherein the slot width of the secondary jet is in the range of 40% to 45 of the slot width of the primary jet.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/154,289 US5014447A (en) | 1988-02-10 | 1988-02-10 | Positive pressure web floater dryer with parallel flow |
| US154,289 | 1988-02-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1315974C true CA1315974C (en) | 1993-04-13 |
Family
ID=22550759
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000590543A Expired - Fee Related CA1315974C (en) | 1988-02-10 | 1989-02-09 | Positive pressure web floater dryer with parallel flow |
Country Status (9)
| Country | Link |
|---|---|
| US (1) | US5014447A (en) |
| EP (1) | EP0328227B1 (en) |
| JP (1) | JP2649180B2 (en) |
| AT (1) | ATE70351T1 (en) |
| AU (1) | AU608689B2 (en) |
| BR (1) | BR8900569A (en) |
| CA (1) | CA1315974C (en) |
| DE (1) | DE68900514D1 (en) |
| FI (1) | FI89951B (en) |
Families Citing this family (26)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2078290A1 (en) * | 1991-10-24 | 1993-04-25 | W.R. Grace & Co.-Conn. | Combination infrared and air flotation dryer |
| US5499673A (en) * | 1992-06-08 | 1996-03-19 | Kawasaki Steel Corporation | Method of and apparatus for conveying and guiding thin metal strip formed by quenching |
| DE4306584C1 (en) * | 1993-03-03 | 1994-07-07 | Langbein & Engelbrecht | Device for the floating guidance of a material web |
| US5536158A (en) * | 1993-10-25 | 1996-07-16 | Eastman Kodak Company | Apparatus for drying solvent based film |
| US5724259A (en) * | 1995-05-04 | 1998-03-03 | Quad/Tech, Inc. | System and method for monitoring color in a printing press |
| US5659972A (en) * | 1995-10-06 | 1997-08-26 | Avery Dennison Corporation | Apparatus and method for drying or curing web materials and coatings |
| DE29602178U1 (en) * | 1996-02-08 | 1996-04-04 | Vits Maschinenbau Gmbh | Hover dryer, in particular offset dryer |
| US5621983A (en) * | 1996-03-29 | 1997-04-22 | Minnesota Mining And Manufacturing Company | Apparatus and method for deckeling excess air when drying a coating on a substrate |
| DE19619547A1 (en) * | 1996-05-15 | 1997-11-27 | Vits Maschinenbau Gmbh | Air cushion nozzle and device for heat treatment of a continuously moving web with air cushion nozzles |
| DE19727326A1 (en) * | 1997-06-27 | 1999-01-07 | Voith Sulzer Finishing Gmbh | Roll cutting device |
| US6007885A (en) * | 1998-03-19 | 1999-12-28 | W.R. Grace & Co.-Conn. | Oxygen scavenging compositions and methods for making same |
| US6280573B1 (en) | 1998-08-12 | 2001-08-28 | Kimberly-Clark Worldwide, Inc. | Leakage control system for treatment of moving webs |
| FI105936B (en) * | 1999-03-18 | 2000-10-31 | Valmet Corp | Method and apparatus for stabilizing the course of a web in a paper machine or the like |
| US6387461B1 (en) | 1999-05-06 | 2002-05-14 | Cryovac, Inc. | Oxygen scavenger compositions |
| DE10007004B4 (en) * | 2000-02-16 | 2006-04-06 | Lindauer Dornier Gmbh | Method for guiding a material web and heat treatment device |
| US6564473B2 (en) | 2001-10-22 | 2003-05-20 | The Procter & Gamble Company | High efficiency heat transfer using asymmetric impinging jet |
| JP3865717B2 (en) * | 2003-06-27 | 2007-01-10 | 東京応化工業株式会社 | Substrate drying apparatus and substrate drying method |
| DE102005054995B4 (en) * | 2005-07-28 | 2014-03-13 | Otto Junker Gmbh | Nozzle system for the treatment of sheet material |
| FI119441B (en) * | 2007-08-20 | 2008-11-14 | Runtech Systems Oy | Method for compensating deformation of a paper web |
| US8083895B2 (en) * | 2008-04-18 | 2011-12-27 | Honeywell Asca Inc. | Sheet stabilization with dual opposing cross direction air clamps |
| US8083896B2 (en) * | 2008-09-26 | 2011-12-27 | Honeywell Asca Inc. | Pressure equalizing baffle and coanda air clamp |
| US9598247B2 (en) * | 2009-09-03 | 2017-03-21 | Game Changers, Llc | Method and apparatus for a dynamic air cushion transport system |
| US10724999B2 (en) | 2015-06-04 | 2020-07-28 | Rolls-Royce Corporation | Thermal spray diagnostics |
| WO2017170714A1 (en) * | 2016-03-29 | 2017-10-05 | 新日鐵住金株式会社 | Liquid removal apparatus and liquid removal method |
| EP3336536B1 (en) | 2016-12-06 | 2019-10-23 | Rolls-Royce Corporation | System control based on acoustic signals |
| EP3586973B1 (en) | 2018-06-18 | 2024-02-14 | Rolls-Royce Corporation | System control based on acoustic and image signals |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3587177A (en) * | 1969-04-21 | 1971-06-28 | Overly Inc | Airfoil nozzle |
| US3873013A (en) * | 1973-10-04 | 1975-03-25 | Tec Systems | High velocity web floating air bar having center exhaust means |
| DE2450000C2 (en) * | 1974-10-22 | 1983-07-07 | Kramer, Carl, Prof. Dr.-Ing., 5100 Aachen | Device for floating material webs on a gas cushion |
| JPS5472847A (en) * | 1977-11-22 | 1979-06-11 | Fuji Photo Film Co Ltd | Method of conveying web |
| US4336479A (en) * | 1978-11-08 | 1982-06-22 | Hitachi, Ltd. | Fluorescent lamp having reflective layer and a method for fabricating the same |
| US4414757A (en) * | 1981-10-07 | 1983-11-15 | Overly, Incorporated | Web dryer nozzle assembly |
| JPS58147366A (en) * | 1982-02-26 | 1983-09-02 | Mitsubishi Heavy Ind Ltd | Apparatus for drying printing paper |
| JPH07106823B2 (en) * | 1986-07-17 | 1995-11-15 | 富士写真フイルム株式会社 | Non-contact web transfer method |
| US4785986A (en) * | 1987-06-11 | 1988-11-22 | Advance Systems, Inc. | Paper web handling apparatus having improved air bar with dimensional optimization |
-
1988
- 1988-02-10 US US07/154,289 patent/US5014447A/en not_active Expired - Lifetime
-
1989
- 1989-01-26 FI FI890391A patent/FI89951B/en not_active IP Right Cessation
- 1989-02-08 AU AU29749/89A patent/AU608689B2/en not_active Ceased
- 1989-02-09 CA CA000590543A patent/CA1315974C/en not_active Expired - Fee Related
- 1989-02-09 BR BR898900569A patent/BR8900569A/en not_active IP Right Cessation
- 1989-02-10 DE DE8989200331T patent/DE68900514D1/en not_active Expired - Lifetime
- 1989-02-10 AT AT89200331T patent/ATE70351T1/en not_active IP Right Cessation
- 1989-02-10 JP JP1032566A patent/JP2649180B2/en not_active Expired - Fee Related
- 1989-02-10 EP EP89200331A patent/EP0328227B1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JP2649180B2 (en) | 1997-09-03 |
| AU2974989A (en) | 1989-08-10 |
| AU608689B2 (en) | 1991-04-11 |
| EP0328227B1 (en) | 1991-12-11 |
| DE68900514D1 (en) | 1992-01-23 |
| FI890391A0 (en) | 1989-01-26 |
| BR8900569A (en) | 1989-10-10 |
| ATE70351T1 (en) | 1991-12-15 |
| EP0328227A3 (en) | 1990-08-16 |
| EP0328227A2 (en) | 1989-08-16 |
| FI890391A (en) | 1989-08-11 |
| JPH0238048A (en) | 1990-02-07 |
| FI89951B (en) | 1993-08-31 |
| US5014447A (en) | 1991-05-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1315974C (en) | Positive pressure web floater dryer with parallel flow | |
| CA1103711A (en) | High velocity web floating air bar having a recessed coanda plate | |
| US4074841A (en) | Method and apparatus for floatation conveyance of strip materials | |
| US4785986A (en) | Paper web handling apparatus having improved air bar with dimensional optimization | |
| FI60261C (en) | OEVERTRYCKSMUNSTYCKE FOER BEHANDLING AV BANOR | |
| JPS5919270B2 (en) | web dryer | |
| CA1308904C (en) | Gas nozzle assembly | |
| FI57142B (en) | MUNSTYCKE FOER BEHANDLING AV MATERIALBANOR | |
| US3837551A (en) | Web conveying and treating method and apparatus | |
| KR100931574B1 (en) | Step air foil | |
| EP0236819A2 (en) | Non-contact web turning and drying apparatus | |
| BR9201333A (en) | DRYING PART OF A PAINTING MACHINE | |
| US3982327A (en) | Air-dispensing web-floating apparatus | |
| US3807056A (en) | Device for the contact-free support of a web of material | |
| US6505792B1 (en) | Non-contact floating device for turning a floating web | |
| US3384282A (en) | Pneumatic conveyor for strip materials | |
| US3452447A (en) | Web positioning means and method | |
| EP0997419A1 (en) | Airbar for use in web processing | |
| SK56998A3 (en) | Blowbox for use in a plant for drying a material web | |
| US5125170A (en) | Flotation dryer nozzle | |
| JP2859355B2 (en) | Levitation guide device for web material by air blown against web | |
| SK42995A3 (en) | Contactless carrying mechanism of fabric | |
| FI54955C (en) | BAERYTETORKARE. | |
| JP2007237151A (en) | Floating nozzle | |
| JP2010269889A (en) | Air float device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |