US2932092A - Low temperature web drier - Google Patents

Description

April 12, 1960 w. ROSENBAUM LOW TEMPERATURE WEB DRIER 3 Sheets-Sheet 1 Filed May 28, 1956 FIG.4

FIG.2

FIG.5

IN VEN TOR. WERNER ROSENBAUM AT TORNEYS FIGIIZ April 12, 1960 w, RQSENBAUM 2,932,092

LOW TEMPERATURE WEB DRIER Filed May 28, 1956 3 Sheets-Sheet 3 \q INVENTOR. WERNE R ROSENBAUM AT TOR VE Y5 United States Patent-D ice r 2,932,092 LOW TEMPE ATURE WEB DRIER 7 Werner Rosenbanm, New York, assignor to Inn, Bloomfield, N.J., a corpus Champlain Company, ration of New York Application May 28, use, Serial No. 587,743 6Claims. (134-159 9 s low temperature; p v

The primary object of my invention is to generally improve driers for a moving web. A more particular object is to provide a drier which will operate efiectively and rapidly at low temperatures. Such a drier may have advantages with any web material,- but is of -=parti cular advantage with webs which may be injured if subjected; to too high a temperature. One example is a wax'laminated foil, which will-delaminate if raised to too high a temperature. Another example is'a web made of Ia plastics material such as polyethylene'which will stretch excessively if overheated. Y

1 In accordancewith th'e-present-invention'the desired rapid drying action is obtained at a reduced temperature by substantially increasing the quantity'of freslr air used for drying. The fresh air has none of the solvent being evaporated from the web. Recirculated or use'd air is already loaded with some solvent,.and;thus the'relative humidity of the solvent is necessarily higher for the ,used air, therefore fresh air will provide maximum drying ability at any specified temperature. Accordingly, one object of the present'invention is to provide a drier which will dependably introducea predetermined large quantity.

of fresh air for mixture with some used or recirculated air;

within the drier. This might be, done by spacing the printing units further apart along: the print line, but that is undesirable because of the resulting increased floor space requirement. It would also be possible to raise the height of the drier hood above the printing press, but that too is undesirable because of limitations in ceiling height. Accordingly, a further object of the present invention is to increase the web area being driedwithout increasing the spacing of the printing units, and without raising the height of the drier.

by a fan. A part of the air was withdrawn by a duct system ,kept under suction (or under a pressure lower than that in the drier), and the withdrawn airwas replaced by the admission of fresh air at a fresh air inlet. Suitable means suchas dampers were employed to regulate the amount of exhaust, as arr attempted measure of specific objects which will hereinafter appear, my inven-' tionresides in the drierelements, and their relation one to another,- as are hereinafter more particularly described a i in the following specification. The specification is accomfl This invention relates to driers for webs, especiallyfo'r' multi-color printing, and more particularly for a rapidly moving printed web whichis to be dried rapidly but at Another object of the invention is to provide an in-.

creased area of web which is subjected to drying action and pulley ofthe' fan removed;

metal rollers willretain-heat for some time.

To accomplish the foregoing objects, and other more panied by drawings, inwhichi Fig. 1 representsa multi-color'printingpress driers; t

Fig. 2 is an elevation of one" of the driers, looking in the directiotrof the arrows 2-2 in Fig. 1;'

Fig.3 is 'a schematic horizontal section through the drier, taken approximately in' the plane of the line 3-3 of Fig. 2;

Fig. 4 is a-similar horizontal section through the drieig', taken approximately in the plane .of the line' 4-4 of Fig; 2; I V

Fig. 5 is a similar horizontal section through the drier,

taken approximately in the plane of the line 15'5 of Fig 2; W 3. t I v 1 Fig; 6 is a similar horizontal section through the drier,

taken approximately-in the plane of the line 6 -6 of .p :p. 1 .u

Fig. "7 is a vertical section taken approxlmately in the plane'of the st pped line 7-7 of Fig. 11;

duct. removed; p r

Fig. 9 is-"a plan view of the drier with the Fig. 8 is a rear' el'eva tion of the drier with the exhaust? Fig. 10' is aibottom view of the'fan enclosure;

Fig. 11 is'apartiallysectioned plan view of the drier} drawn to larger scale;

Fig. 12 is a detail showing cooling nozzles used temporarily'when the web is stopped; Fig. 13 shows the nozzles to larger scale; and

Fig. 14 is a front elevation of the drier.

Referring to the drawing, and more particularlytoj Fig. 1 a web to be printed is supplied from a web holder I In prior practice the air in the drier was recirculated the ratio of fresh to used air. (However, such a system is most uncertain in result. One may safely assume that the exhausted air is replaced by fresh air, but because,

some of the fresh air can be drawn into the exhaust duct, there is no way of assuring uniformity of the saturation of air circulating within the drier itself. A further object of the present invention is to overcome this difficulty, and to effectively prevent the fresh air from reaching the exhaust duct, thereby insuring that the latter receives solely used air.

In its passage through the drier the web runs 'on metal rollers. These are subjected to the temperature'within the drier. During operation the web moves over the rollers too rapidly to reach the roller temperature, but on stoppage of the press the web remains stationary on'the 12 fromwhich the web is drawn by a suitable pull unit 14 and supplied to gravure multi color printing press units 16,18,20 and 22. The web is taken up in a suita; ble take-up unit 24, although it may equally well go to a punch press or/and slitting and cutting means and a stacker for sheets. The printing units are provided with individualdriers indicated at 26, 28,30 and 32. The printing action is performed between a gravure cylinder 34 and an impression roll 36, following which the webf feeds'upwardly and then downwardly through the drier and thence'on to 'thenext printing unit 18. The roll support 12 is preferably arranged to hold two rolls 38,1 and 40in order to facilitate changing quickly from an' exhausted paper roll to a new paper roll.

In- Fig. '1 it willbe noted that each drier comprises an .invertedfU-shaped hooddisposed around the top"of.th e" pressandfhaving a'-, top portion 42 (see the last drier)v above the press, and leg portions 44 and 46 alongthe sides 'of the-press. 'Hereto'fore' thetop portion 42 was employed as a housing for a circulating fan and for heat exchangers which were disposed directly over theprint ing press. 7

Referring now to Fig. 7' of the drawing, I provide a top roller 50 at the top of the drier, and nozzle plates for directing heated air against the web are provided not] only in the leg portions 44 and 46; as shown at 52 and 54, but also in the top'portion 42, with the nozzle plates preferably sloping toward one another and toward' the top roller 50, as shown at 56 and 58.

Referring nowto Figs. "2- and 11 of the drawing, the

Patented Apr. 12," 1

line with? drive belt fan, generally designated 60, and the heat exchangers 62 and 64 (Fig. 11) are housedin an enclosure 66 which is mounted at one side of the top portion 42 of the drier and-offset from the printing press line. This enables the entire height of the hood to be utilized for nozzle plates, as shown in Fig. 7, thus providing additional cooling area on the web without increasing the overall height of the drier.

In Fig. 2 it will be seen that the drier resembles the Construction heretofore used in that the hood is wider than the printing press 16 (and the web 17 being handled thereby), or, as seen in Fig. 11, the hood is wider than the nozzle plate 56. The hood has partitions 68 and70 at the side edges of the nozzle plates to divide the hood into unused or hot air passages or plenum chambers outside the nozzle plates between the partitions, and used air passages within or between the nozzle plates and also alongside the nozzle plates. This will be explained in greater detail later, but as a preliminary example, in Fig. 3, which is a horizontal section through the leg portions 44 and 46 of the drier, the partitions 68 and 70 confine heated air to the space or plenum chamber 72 where it is, directed through the nozzle plate 52 against the web74. The used air then flows laterally into the side portions 76 and 78 of the leg, where it can rise upwardly for recirculation or exhaust.

' Referring now to Figs. 2 and 7 of the drawing, I employ a double-ended or double inlet fan 60, the shaft 80 of which is disposed vertically. One inlet, the upper inlet 82, is connected for fresh air intake exclusively, and this is, provided through the top of the offset enclosure (Fig. 2) is connected to the used air passages of the hood and thus receives air which has already passed through the nozzle plates. The heat exchangers 62 and 64 (Fig.,11) are disposed between the fan outlet and the hot air passages or plenum chambers leading to the nozzle plates, and there are suitable partitions, primarily horizontal partitions 90 and 92 disposed adjacent the bottom of the heat exchangers to insure that thefan discharge can go. only to and through the heat exchangers and thence solely to the nozzle plates. There is also an exhaust duct 94 (Figs. 2, 4 and which communicates with the used air passages of the hood, and which preferably includes a damper 96 (Figs. 2 and 8). Thebottom fan inlet 88 is connected to the horizontal partition 90, which is .disposed somewhat higher than the bottom 98 of the enclosure 66. The exhaust duct 94 communicates with the' resulting bottom region of the enclosure below the horizontal partition 90.

Referring now to Fig. 4, which is a horizontal section taken through the bottom portion of the enclosure 66, it will be seen that the vertical partitions 68 and 70confine the heated air to the plenum chambers and nozzle plates 56 and 58, but that the used air is free to flow to the bottom portion 100 of the enclosure 66 and thence to the duct 94. It is also free to rise upward through the bottom inlet 88 (not shown in Fig. 4) ofthe fan.

In Fig. 5, which is a horizontal section above the partition 90, through the fan rotor, it will be seenth-at the fan is located in a six-sided prismatic region defined by and will either be exhausted, or, if reused, will first reheated before being ready for reuse.

Fig. 6 is a horizontal section taken near the top of the offset enclosure 66, and shows the top fan inlet at 82. Here again the six-sided polygonal outline divides the upright fan from the heat exchangers. The latter are blocked at 63 and 65, that is, their inner faces, to pre- 4 vent return flow, In the region of Figs. 5 and 6 the used air may flow between the Webs 74 within the nozzle plates 56 and 58 toward the fan compartment, but then flows downward to the bottom of the offset enclosure 66, that is, to the region 100 shown in Figs. 2, 4 and 7.

' temperature.

the heat exchangers 62 and 64, vertical 'walls 102,; 104

and 106, and the outer wall 108 of the offset enclosure 66. Thus the fan discharge has nowhereto go except through the heat exchangers 62 and 64, and thence to the hot air passages or plenum chambers 110 and 112 outside the nozzle plates 56 and 58. The air leaving the heat exchangers is partly fresh air, and partly used air which has been reheated. For convenience this description differentiates between hot air passages and used air passages, in the sense that hot air has been heated preparatory to use on the Web, and has not yet been used for that purpose since its last heating, whereas used In general, the arrangement is such that fresh air cannot reach the exhaust duct 94 without first passing through the upper fan inlet 82, the fan 60, and thence through the heat exchangers 62 and 64, and then through the nozzle plates where it is directed against the web. Differently expressed, the arrangement precludes fresh air from bypassing the heat exchangers and the nozzle plates. Conversely, the used air leaving the nozzle plates and web cannot gain access to the upper fan inlet 82. It can reach either the lower fan inlet 88 or the exhaust duct 94. The amount of air exhausted may be controlled by suitable means, including the damper 96, and a remote exhaust fan, not shown. The exhausted air is necessarily replaced by fresh air, but the fresh air can enter only at thetop fan inlet. Thus the system'as a whole definitely fixes the ratio of fresh air to used air, in the hot air mixture, and permits this ratio to be made quite large, say 50% or more.

Referring to Fig. 7 of the drawing, the fan rotor comprises a hub 114 carrying an annular plate 116 acting as a divider between upper blades 118 and lower blades 120. In the present case the fan is perfectly symmetrical, and the plate 116 divides the rotor into two equal halves, so that in effect the fan may be considered to be two similar fans disposed back to back. The upper fan handles fresh air exclusively, and the lower fan handles recirculated or used air exclusively. It is believed that the dividing plate 116 is not essential, and that the operation would be substantially the same even without the plate 116, reliance then being had on the symmetrical construction to produce substantially the same result. However, the plate 116 is anyway desired for structural reasons, and it does help to more definitely fiix the divided action of the double-ended fan.

The top roller 50 is disposed above the top of the drier hood. This is done even though it necessitates the provision of slots at 122 and 124 (Fig. 9) for passage of the web to the roller 50. Putting the roller outside the hood slightly increases the nozzle area, but the main reason for elevating the roller is to let it run cool instead of hot. During operation the web travels at high speed and is in contact with the roller only momentarily, but if the press is stopped for any reason the web remains in contact with the roller, and a hot roller will tend to injure a web which must be kept at low The next lower guide rollers 126 and 128 (Fig. 7) are necessarily inside the hood, and become hot. To

. avoid difiiculty in the event of shutdown I provide compressed'air nozzles, indicated at 130 and 132 and connected by a cross pipe indicated at 134. These blow cold air for a short time between the web and the roller, and thus serve to separate the web from the roller, as well as to cool both. The nozzles 130 and 132 are shown in greater detail in Figs. 12 and 13. They are rectangular in section, and preferably are connected at both ends by cross pipes 134, which serve also to mount the nozzles in position, as by means of brackets 136 secured to the walls of the hood. The bottom edge of each nozzle is. provided with small spaced perforations 138. The nozzles and connecting pipes form a rectangle, as will be seen in.Fig 11, with an. outside connection at 140.

ina printing plant.- The air pressure may be, -say,'i 80 lbs. per square inch. The compressed air is used fora only a few minutes immediately onshutdown 'of thepress for any reason, .and it isnot used during operation of :the

press. There is an electrical interlock, not shown, whereby shutting down of the press automatically opens a solenoid operated air valve to supply the compressedair for a predetermined time period, and when the time runs out the valve is automatically closed. An interlock also shuts off the fan 60.

Referring now to 'Figs. 11 and 14, the fan motor is indicated at 142. It is mountedwith its shaft parallel to .the fanshaft, and the two are operativelyconnected, as, for example, bya 'V belt and" pulley drive. In the present'case there is a double V pulley: 144 on the motor and a double V pulley .l46 -at the upper end of the "fan shaft, these being connected by V belts'148, (omitted in Figs Z-and 9). r Pipecon'nection's forthe-heat exchangers areprovided outside the fan enclosure, indicatedat 150'in Fig; '1 1."

'The leg portions 44 and 46 (Figs. 7 and 14) of the' hood are hinged to the topportion 42 of the hood at 152. They may be swungoutwardly after releasing latches 154 (Fig. 7), thereby facilitating the threading of aweb through the=drier. j This threading operation-is aided by the access door 156 (Fig. 14) hinged at'158, which is located at the ends of the rollers 126, 128. The

top 'roller 50- would still-provide some difiiculty because of its height, and to facilitate threading the web I provide a sprocket'chainme'chanism next described.

Thetop roller 50 (Fig. 11) turns freely on a stationary shaft 160. On the same shaftI-GO sprocket Wheels 162 (Fig. '9) are mounted, one at each-end ofroller 50, 'and also are freely rotatable on the stationary 'shaft 160. Within thehood directly below the roller 50 a shaft 164 (Figs- 2, 7 and 11) is mountedin bearings secure'd at the-sides of the hood itself. Oneof these bearings isshownat 166 in Fig. 11, audit will be seenthat' shaft 164 does not-pass through the fan enclosure. I Shaft l64 carriessprocket wheels 168 which,in the present case, are substantially largerin'diameter than the top sprocket wheels 162. Chains 170 (Fig. 7) run about the sprocket wheels and carry the ends of a threading bar 162which extends parallel to the shaft 164. The bar 162 is provided with 'means to 'grip' the end of a new web. Shaft 164 projects out of the hood at one end, and has a squared end- 17 2" (Figs. 11 and 14) to receive an operatingcrank. This crank is'schematically indicatedat 174in Fig. 2, and by passing the end of a web over roller 128 (Fig. 7),

and securing it to bar 162, the crank and chain system may be used to carry the web'up and around the top roller 50 and then down to a point near the roller 126, where the end of the web may be detached from the bar and passed around roller 126. The legs 44 and 46 of the hood are turned up at this time to facilitate handling the'web.

'FIhe sloping surface indicated at 180 in Figs. 7 and 11 is merely a deflectingvane to help guide the heated air leaving theeXchang'er 62 against the nozzle plate '56.

A similar deflectoris provided on th Opposite l n the "hood.

"Ihe" connection to the exhaust duct system of the printing plant is made at the rectangular opening'94 The operating temperature of ordinarydriers is about: .F. The present drier 'operates etficiently at a drying temperature of only 130 F. Provision is also made at the bottom of the.fan enclosure, similar to the doors 84, 86 previously described as located at the top of the fan enclosure. Fig. 10 is a bottom plan view of the fan enclosure, and it will be seen that the construction is substantially the same as that at the top. shown in Fig. 9. There are doors 186 and 188. (Fig. 10) hinged along the edges of a stationary center part 190 which. carries the lower bearing for the fan shaft .80. .These bottom doors, like the top doors, outline the polygonal shape of the fan enclosure, andwhen opened admit fresh -air.to the bottom fan inlet, thus adding to the fresh.

air. normally admitted by the top doors to the top fan inlet. The open position of the bottom doors is indicated in brokenlines in Fig. 8. fresh to used air is less positively determined, because the-bottom. fan inlet is in communication with the exhaust duct, but the ratio is more definite than in an ordinary drier because any indefiniteness applies to only a fraction of the fresh air instead of to all of it. Moreover, in all ordinary operating circumstances as.now

planned, the bottom doorsremain closed, and adequate:

fresh air is available through the top doors alone. I

The particular fan here illustrated is a'Sturtevant double width double inlet design. The. motor is an explosion-proof motor running at '3600 r.p.-m;, but the 'fan speed is reduced to 2100 r.p.m. The heat exchangers are four row exchangers, also madeby Stur'tevant. gThe damper in the exhaust ductis madeby Parker Kalon, and turns on a horizontal shaft.

The nozzle plates have thirty-four nozzles, each extendingacross the width of the plate,',and'each having an opening of 0.165". The openings may be given a nozzle shape as explained ingreater detail inCaulfield Patent f 2,554,239 issued May 22, 1951;

It is believed that'the construction and operation of my improved lowtemperature drier, as well as the advantages thereof, will be apparent from the'foregoing detailed-description. The-drier will take care of a printed web running at high web speed, although operating at a low temperature which is safe for webs sensitive to elevated temperature. This is' done by the provision,

of an increased amount of fresh air, and by accurately and dependably maintaining a desired fresh air ratio. Moreover, the area subjected to drying is increased Without, however, increasing the overall height of the drier, and without increasing the spacing between successive printing units.

described my invention in a preferred form, changes may be made in the structure'shown, without departing frorn'f the scope of the invention, as sought to be defined in the i following claims. In the claims the term hot air'refers used air as well as fresh air, and the used air is still hot after delivery to the web, although not as hot'a s before delivery'to the web.

I claim:

1. A drier for a gravure press, saidldrier comprising an inverted U-shaped hood disposed around the top "of intozhot air plenum chambers outside thenozzle plates;

In such case the ratio of- It will be apparent that while I have shown and" to the air prior to its delivery to the web. Theterm.

the press and having a top portion over the press and leg portions along the sides of the press, nozzle plates in the leg portions and in the top portion, said hood being and used air passages within and alongside the; nozzle municating with the used air passages, heat exchanger means disposed between the fan outlets and the hot air plenum chambers leading, to the nozzle plates, and an' exhaust duct communicating with the used air passages, the arrangement being such as to preclude fresh air from bypassing the heat exchanger means and nozzle plates.

2. A drier for a gravure press, said drier comprising an inverted U-shaped hood disposed around the top of the press-and having atop portion over the press and leg portions along theisides of the press, nozzle plates in the leg portions and in the top portion, said hood being wider than said. nozzle plates and having partitions at the side edges of the nozzle plates to divide the hood into hot air plenum chambers outside thenozzle plates, and used'air passages within and alongside the nozzle plates, a double inlet'fan, means connecting one of the fan inlets to a fresh air intake exclusively, the other of said inlets being connected to the used air passages for'recirculating air which has already passed through the nozzle plates, a heat exchanger disposed between the fan outlet and the hot air plenum chambers leading to the nozzle plates, an exhaust duct communicating with the. used air passages of the hood and incidentally with thesecond of said fan inlets, the arrangement being such as to preclude fresh air from by-passing the heat exchanger and nozzle plates.

3. A low temperature drier for a gravure press, said drier comprising an inverted U-shaped hood disposed around the top of the press and having a top portion over the press and leg portions along the sides of the press, nozzle plates in the leg portions and in the top portion, said hood being wider than said nozzle plates and having partitions at the side edges of the nozzle plates to divide the hood into hot air plenumcharnbers outside thenozzle plates, and used air passages within and alongside the nozzle plates, a symmetrical double inlet fan, means connecting one of the fan inlets to ajfresh air intake exclusively, doors at said intake to regulate the amount of fresh air intake, the other of'said inlets being. connected to the used air passages for recirculating air which has already passed through the, nozzle plates, oneor more heat exchangers disposedrbetween the fan outlet and the hot air plenum chambers leading to the nozzle plates, partitions in said hood directing the fan discharge to the hot air plenum chambers exclusively, an, exhaust duct communicatingwith the used air passages of the hood andrincidentally with the second of said fan inlets, a damper to regulate the exhaust air, the arrangement being such that fresh air cannot reach the exhaust duct, without first passing through a heat exchanger and a nozzle plate.

'4. A drier for a gravure press, said drier comprising an inverted U-shaped hood disposed around the top of the press and having a top portion over the press and leg portions along the sides of the press, a top web roller disposed near the top of the top portion, nozzle plates in the leg portions, and nozzle plates in the top portion leading to.a top roller, said hood being wider than said nozzle plates andhaving partitions at the side edges of the nozzleplates to divide the hood into hot air plenum chambers outside the nozzle plates, and used air plenum chambers within and alongside the nozzle plates, a fan and heat exchanger enclosure mounted at one side of the top-portion andoffset from the printing press line so that the height of the hood may be utilized for nozzle plates, a first fan inlet connected to a-wall of the enclosure, a second fan inlet communicating with the used air passages, heat exchanger means disposed between the fan outlets and the hot air plenum chambers of the hood, whereby the fan discharge is directed to the nozzle plates exclusively, and an exhaust duct communicating,

with the used air it passages, the arrangement being such" that fresh air calmer reach the e'xhaust duct without'first" passing through a heat exchanger means and a nozzle plate.

5.: A' drier for a gravure press,

leg portions along the sides of the press, a top web roller disposed, near the top of the top portion, nozzle plates in the leg portions, and nozzle plates in the top portion leading. to the top roller, said hood being wider than said nozzle plates and having partitions at the side edges of the nozzle plates to divide the, hood into hot air passages outside the nozzle plates, and used air passages within and alongside the nozzle plates, a fan and heat exchanger inlet to a wall of the enclosure for fresh air intake ex-' clu'sivelyn means connecting the other inlet of said :fan

to a horizontal partition disposed somewhat higher. than the bottom of said enclosure and the resulting bottom portion communicating with the used air passages, aheat exchanger in said enclosure between the fan outlet and the hot air passages of the hood, whereby the fan discharge is directed to the nozzle plates exclusively, and:

an exhaust duct communicating with the aforesaid bottom portion of the enclosure below said horizontal partition, the arrangement being such that fresh air cannot reach the exhaust duct without first passing through the fan and heat exchangers and nozzle plates.

- 6. A low temperature drier for a gravure press, said drier comprising an inverted U-shaped hood disposed around the top of the press and having a top portion over the press and leg portions along the sides of the press, a top web roller disposed above the top portion,- nozzle plates in the'leg portions, and nozzle plates in the top portion sloping toward one another and toward the top roller, said hood being wider than said nozzle plates and having partitions at the sides of the nozzle. plates to divided the hood into hot air passages outside the nozzle plates, and used air passages within and alongside the nozzle plates, a fan and heat exchanger enclosure mounted at one side of the top portion and offset from the printing press line so that the entire height of the hood may be utilized for nozzle plates, a symmetrical double inlet fan with upright shaft in said enclosure,

means connecting the top fan inlet to doors in the top wall of the enclosure for fresh air intake exclusively, means connecting the bottom inlet of said fan to a horizontal partition disposed somewhat higher than the bottomof said enclosureand the resulting bottom portioncommunicating with the used air passages, heat exv changers disposed vertically in said enclosure above-said horizontal partition on each side of the fanbetween the fan outlet and the hot air passages of the hood, whereby the fan discharge is directed to the nozzle plates exclusively, an exhaust duct communicating with the aforesaid bottom portion of the enclosure below said horizontal partition, and damper means in said exhaust -duct to regulate the exhaust air,,the arrangement being such that fresh air cannot reach the exhaust duct without first passing through the fan and heat exchangers and nozzle plates.

said drier comprising aniriverted U-shaped hood disposed around the. top of" the. press and having a top portion over the press and-

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