US2365271A

US2365271A - Drier drum

Info

Publication number: US2365271A
Application number: US480054A
Authority: US
Inventors: Hornbostel Lloyd
Original assignee: Beloit Iron Works Inc
Current assignee: Beloit Iron Works Inc
Priority date: 1943-03-22
Filing date: 1943-03-22
Publication date: 1944-12-19
Anticipated expiration: 1961-12-19

Description

Dec. 19, 1944.

L. HORNBOSTEL DRIER DRUM Filed March 22; 1943 3 Sheets-Sheet 1 1401 0 Hoe/vaasrA-L.

"Dec. 19,'1944-. HORNBOSTEL 2,365,271

DRIER DRUM Filed March 22, 1943 3 Sheets-Sheet 2 ULEZ 224:1

i1 .EZQE- Deg. 19, 1944. HORNBOSTE'L DRIER DRUM Filed March 22, 1943 3 SheetSQ-Sheet 3 Patented Dec-19,1944

amn DRUM Lloyd Hornbostel, Beloit, Wis., assignor to'Belcit Iron Works, Beloit, Wis., a corporation of Wilcousin Application March 22, 1943, Serial No. 480,054

11 Claims.

This invention relates to rotatable drum constructions equipped with stationary heating means adapted to heat the drum without subjecting the drum structure to pressures in the heating means.

Specifically, the invention relates to drier drum constructions for paper making machines which are equipped withinternal steam heated boilers for vaporizing a high temperature boiling material in the drum to-heat the drying surfaces of the drum without subjecting the drum structure to the steam pressures in the boiler.

The invention will hereinafter be specifically described as embodied in a paper machine drier drum, but it should be understood that the invention is not limited in scope to such' an embodiment, since the constructions and methods of this invention are generally useful in many fields.

High speed paper making machinery, and especially those types of paper making machines having one large drier drum for drying the newly made paper sheet require drying drums with 'the transfer of heat from the steam to the paper so that the increased steam pressure gives very little increased drying capacity to the drum. In addition, the thicker walled drums are very heavy and require added driving efiort to be rotated.

According to this invention, drier drums are equipped with internal stationary steam chests or steam-heated boilers. These chests or boilers are mounted inside of the rotatable drum and, being stationary, no steam fittings are necessary, such as are required when steam is fed directly into a rotating drum. In addition, according to this invention, open-topped baskets are stationarily mounted inside of the drum to receive high boiling point materials which can be vaporized by heat from the chests or boilers to condense can be heated with high pressure steam without subjecting the drum construction to steam pressure and at the same time efliciently transfer heat from the steam to the drying surface of the drum. C

Any material having a high boiling point, and being relatively inert so as to eliminate corrosion of the drum, can be used. A very satisfactory material is a eutectic mixture of diphenyl and diphenyl oxide. This material is a colorless, non-corrosive liquid stable up to 725 C. and having a boiling point of 258 C. with a heat of vaporization of 123 B. t. u.s per pound at the boiling point. This material is known commercially as Dowtherm.

With such high boiling-point heat transfer liquids, the steam boiler or steam chest can be heated with steam at temperatures, for example, around 850 pounds per square inch pressure. Such steam will have a high enough temperature to boil and vaporize the high boiling liquid. However, the vaporized liquid will be only slightly above atmospheric pressures and, as a result, the drum construction can be exceedingly light since it does not have to withstand high pressures. As a safety feature, this invention provides seals for the drum construction which will vent. the vaporized liquid out of the drum in the event that its pressure increases above a desired amount.

heating a heat-transfer material which emciently transfers the heat from the boiler to the drying surface of the drum.

A still further object of the invention is to provide a rotatable drier drum with a stationary internal steam chest and heat transfer material between the steam chest and the drum for conveying heat from the chest to the drum.

Another object of the invention is to provide a drier drum construction wherein high pressure steam is passed through a stationary heat transfer device in the drum without subjecting the drum to the steam pressure, and wherein the heat transfer device is effective to vaporize a high boiling liquid in the drum for condensing on the drum surface to heat the same.

Ai'urther object of the invention is to provide a method of heating rotating drums by vaporizing a high boiling material in the drum, condensinggthe vapor on the heating portion of the drum, and revaporizing the condensate in the drum.

A still further object of the invention is to provide a drier drum assembly receiving high pressure steam therethrough without subjecting the drum construction to the steam pressure, I

4 ized in the drum.

A still further object of the invention is to provide a safety seal for rotating drier drums effective to liberate excessive pressures from the drum.

Other and further objects of the invention will be apparent to those skilled in the art from the following detailed description of the annexed sheets of drawings which, by way of preferred example only, illustrate one embodiment of the invention.

n the drawings:

Figure 1 is a side elevational view of a drier drum assembly according to this invention.

Figure 2 is an enlarged transverse cross-sectional view of the drier drum taken along the broken line 11-11 of Figure 1.

Figure 3 is an enlarged longitudinal cross-sectional view, with parts in elevation, taken along the broken line III-III of Figure 1.

Figure 4 is an axial cross-sectional view taken along the line IV-IV of Figure '3.

As shown on the drawings:

As shown in Figures 1 and 4, the reference numeral l0 designates generally a drier drum according to this invention having a cylindrical peripheral wall ll adapted to receive a web of paper thereon, end walls or heads l2-l2 secured to the ends of the cylindrical wall H, and hollow trunnions I3-l3 projecting outwardly from the centers of the heads l2-l2 and rotatably mounted in bearings l4-l4 carried by pedestals I5-l5 of end frames lG-IB. A driving gear I! is secured around one trunnion I3 to rotate the drum l0.

As best shown in Figure 4, hollow shafts ll-l 2 project freely through the trunnions IS-II and have outwardly flanged ends l9-l9 in the interior of the drum Ill. The outer ends of the shafts l8-l8 are carried in supports 20-20 on pedestals 2l-2l of the same end frames l8-l8. These supports 20 grip the shafts Hi to hold the same in spaced relation from the trunnions It. A semi-cylindrical open-topped metal basket or trough 22 is mounted in the drum l0 and has a hollow tubular hub 23 extending across the open end thereof between the flanges 18 of the shafts l8. Hollow-header disks 24 are interposed between theends of this tubular portion 23 of the basket 22 and the flanges i9 and bolts 25 pass through end flanges 23a of the tube 23, through the disks 24, and through the flanges it to clamp the disks 24 between the tube 23 and the flanges l9 and to suspend the basket 22 in the drum in spaced relation from the drum walls.

Each disk 24 has a chamber 28 therein. A

steam inlet pipe 21 passes freely through one of the hollow shafts II to discharge into the chamber 28 of one disk 24. The other disk 24 has a steam outlet pipe 28 communicating with the chamber 26 thereof and passing through the other shaft l8.

Each disk 24-24 has a plurality of depending hollow boss portions 28 around the bottom thereof communicating with the chamber 28 of the disk.

The opposed end walls of the basket 22 carry a plurality of aligned pairs of steam headers -30. A plurality or bank of steam tubes ll extend through the basket 22 and connect the headers 30-39 of each pair.

Elbow pipes 32 connect two adjacent headers 30 on each end wall of the basket to couple three pairs of headers 30-30 in series so that steam will flow into one header 30, through the bank of tubes 3| into the opposed aligned header 3. and will then flow through an elbow pipe 22 into an adjacent header 30 011 the same end wall for flowing back through a second bank of tubes 21 into the opposed header 30 and then through an other pipe 32 into an adjacent header other than the first mentioned header on the same end wall of the basket back througha third bank of tubes into the opposed header.

As shown in Figure 2, four groups each containing three sets of headers are provided with the headers of .each group connected in series.

Steam supply pipes 33 each connect a boss 2! of one disk 24 with a header of each group for supplying steam to each group of headers and tubes. Pipes 34 likewise connect the end header Ill of each group to the bosses 28 on the other disk 24.

With this arrangement, steam will flow through the pipe 21 into the bosses 29 and thence through the tubes 33 into the first headers of each group. The steam will. flow from these headers through the first bank of tubes into the opposed aligned headers, thence through the elbow pipes 32 back through the second group of tubes, thence through a second elbow pipe 32 through the third group of tubes and into the pipes 84, which discharge through the bosses 29 of the other disk 24 and out through the pipe 28. With this arrangement, the steam must traverse the basket three times between the

pipes

21, and 28 and four identical paths are provided for the steam. This arrangement will uniformly heat the contents of the basket 22 to vaporize the high boiling heat transfer material.

The cylindrical wall ll of the drum has diametrically opposed scoops 35 secured to the inner face thereof intermediate the heads l2-l2. Scrapers 38-36 are secured to the upper end of the basket 22 and scrape the inner surface of wall II. The scrapers extend beyond the end walls of the basket for terminating adjacent the heads l2-l2. These scrapers 36-36 are positioned suiflciently far apart so that the scoops 35 y will clear the inner ends thereof.

When the drum l0 rotates in the direction of the arrow shown in Figure 2, the scoops 25 will pick up condensate in the bottom half of the drum and will discharge the same over the basket 22' to drop into the basket. the scrapers 36 will be effective to scrape ofl condensate film from the drum and direct the condensate back to the basket. Experiments have shown that the return of the heat transfer liquid to the basket is most efliciently effected by positioning the scrapers 88-36 at the ends of the drum cylinder II and by positioning the scoops In addition,

', ascaa'n der II sufllciently for the scoops 35 to have operating clearancerelative to the basket.

As best shown in Figure 4, a seal casing 31 is secured on the end face of the trunnion I3 ad- Jacent the gear I]. This casing houses a pair of spaced diaphragm rings 38. The inner ring 38 carries a seal ring 38 on its inner face. The shaft I8 carries a cooperating seal ring 48 in sliding face engagement with the ring 38. The outer face of the other ring 38 carries a seal ring H in sliding .face engagement with a cooperating seal ring 42. A sealed space 43 is thus provided between the rings 38 and springs 44 are mounted in this space to urge the rings 38 apart for holding the cooperating pairs of seal rings in sliding face engagement. I

The shaft I8 has a radial bore 45 therein communicating with the sealed space 38. This bore 45 communicates with a longitudinal bore 48 in a lug 41 formed on the shaft I8 and projecting into the hollow interior thereof. A pipe 48 communicates with the bore 48.

The opposite end of the drum has a seal casing '48 secured to the end face of the opposite trun-' nion I3 and surrounding the shaft I8. This casthereof for rubbing engagement with a cooperating seal ring 52 on the shaft I8 in a manner similar to the inner ring 38. However, the outer ring 58 carries its seal 53 on the inner face thereof as contrasted with the outer ring 38, which carries its seal 4| on the outer face thereof. The shaft I8 has a cooperating seal ring 54 thereon engaging the ring 53.

A sealed space 55 is thus provided between the diaphragm rings 58. A casing carried liner 58 holds the rings 58 apart and this liner has a rib or flange extending into the space 55. This space 55 communicates through bores 45 and 46, identical with those described above but in the opposite shaft I8 with a continuation of the pipe 48. J

A set of springs 51 is mounted in the space: 55 to act on the inner ring 58. These springs 51, instead of being bottomed on the other ring u in vapor form, and fed back in liquid form to the basket.

An overflow pipe 83 is provided in the upper portion of the basket" and this pipe discharges,

into a hollow lug 31 formed in the opposite shaft I8. A discharge pipe 88 receives the excess heat transfer material from the hollow lug 81 and extends through the shaft I8 to discharge outside of the drum construction.

The seals on both ends of the drum are ar I ranged so that they will operate most efllciently when the spaces 43 and 55 therebetween are under partial vacuum. The inner diaphragm ring 38 and the inner diaphragm ring 58'are adapted to be deflected by excess pressure of the heat transfer means in the drum 'for relieving this pressure to the vacuum spaces which, by means of being connected to a vacuum pump, will discharge into the condenser for liquefying the heat transfer medium. The outer diaphragm 38 is not adapted to carry its seal 4I away from the cooperating seal 42 when the space 43 is subjected to pressure. However, the outer diaphragm ring 58 is adapted to be deflected by excess pressures in the space 55 for discharging the heattransfer means through the holes 58 in the casing cover 58 inthe event that the vacuum pump is not suflicient to relieve the pressures, or for any reason is inoperative. The seal in the casing 49 thus also acts as a safety valve.

As shown in Figure 8 and 4, the headsor end walls IL -I2 of the drum are preferably covered 58, arebottomed on the rib of the liner 58 and urge the ring 5| against the ring 52.

The casing 58 has a cover 58 with perforations 58 .therethrough. This cover. cooperates with the outer ring 58 to provide a space in which an additional set of springs 88 are mounted for acting on the outer ring 58 to hold its seal ring 53 against the cooperating ring 54.

The spaces 43 and between the diaphragm rings of the seals on opposite sides of the drum are evacuated through the pipe line 48 by means of a vacuum pump M as shown in Figure. l. A condenser 82 is provided in advance of the pump 8I forcondensing any vapor passing through the pipe line 48. The pump 5| discharges. into a pipe line 83 which, as shown in Figure 4, extends into the shaft I8 having the gear II therearound. Thisshaft I8 has a hollow lug 54 receiving the end of the pipe 83 and this hollow lug 54 discharges through a pipe 85 into the basket 22. By this arrangement, any heat transfer material leaking past the seals 38 and 5| will be condensed,

with insulating material I8 plates. 'II. Likewise, as shown in Figure 4, the interiors of thetrunnions or journals I3--I3 are lined with insulating material I2 protected by a cover I3. Manholes I4 are provided in the heads I2-I2 and these are covered by insulation lined plates I5. This insulation makes the cylinder II the only heat-radiating surface. This cylinder is preferably composed of an eflicient heat-transfer metal such as a fine grade of cast iron capable of retaining its shape over a long period of years cooling. The heat radiating cylinder II can be made rela-' tively thin since it is not subjected to appreciable when subjected to repeated heating and internal pressure.

From the above descriptions it will be understood that this invention provides a heating drum or drier drum construction wherein a shell has hollow trunnions or journals rotatable in bearing supports and receiving therethrough stationary shafts which carry a heat transfer liquid containing basket and a steam chest in the interior of the shell in spaced relation therefrom. steam chest and basket are stationary and stationary steam connections pass through the supporting shafts for supplying and removing heating fluid to the chest. The arrangement is such that high pressure steam can be supplied to the steam chest without subjecting the interior of the shell to steam pressure. The shell is heated by an efficient heat-transfermaterial having a high boiling point and capable of being vaporized by heat from the steam chest to condense on the interior of the shell and be returned back to the basket.

protected by outer The Scoops and scrapers are provided in the drum to return condensate from the shell to the basket.

It will, of course, be understood that various details of construction may be varied through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

I claim as my invention:

1. A drier drum comprising a metal cylinder, heads sealing the ends of said cylinder, hollow journals projecting outwardly from said heads, means rotatably supporting said hollow journals for rotatably mounting the cylinder, stationary supports extending freely through said interior of the drum, and means outside of said drum stationarily carrying said boiler and said terial reaches a predetermined pressure, a condenser for receiving material passing said seal means, and a pump for recirculating the condensed material back to said drum.

6. A drier drum comprising a hollow drum having hollow journals, bearings rotatably supporting said journals, hollow shafts projecting freely through said journals, stationary supports spaced laterally from said journals carrying said hollow shafts, steampipes extending through.

other distributor member with each group of series connected tubes, means in said drum adapted to discharge material from the drum into said basket, and seals between said jourcontainer in said drum independently of said trunnions.

3. A drier drum comprising a hollow drum having hollow rotatably mounted supporting journals, stationary hollow shafts projecting through said journals, an open-topped basket in said drum having a closed steam passage therethrough, said basket suspended in said drum on said stationary hollow shafts in spaced-relation from the drum, a steam inlet pipe projecting through one hollow shaft for supplying steam to the steam passage of the basket, a steam outlet pipe passing through the other hollow shaft to remove steam and condensate from said steam passage, said basket adapted to contain a high boiling liquid, scoops mounted on the interior of said drum for discharging liquid from the drum into said basket, and scrapers mounted on said basket acting on the drum for directing condensate into the basket, said scrapers and scoops being arranged so that the scoops can pass between the scraperswlthout contacting the scrapers.

4. A drier drum construction comprising a rotatably mountedhollow drum, a stationary steam chest in said drum, a basket for high boiling liquids in said drum, seal means on said drum adapted to pass vapors and liquids from the drum, suction means for drawing the liquids and vapors passing said seal means, a condenser for condensing the removed vapors, and means for returning the condensed vapors and liquids back to the basket in the drum.

5. A drier drum comprising a rotatably mounted hollow drum, an open-topped basket stationarily mounted in said drum in spaced relation therefrom, means providing a high pressure steam passage through said basket, said basket adapted to contain a heat transfer liquid capable of being volatilized in the drum, seal means on the drum arranged to pass heat transfer material out of the drum whenever said manals and said hollow shafts for sealing the interior of the drum.

'7. In a drum construction having a hollow journal, a seal casing carried by said journal, a shaft extending through said journal in spaced relation therefrom to provide a passageway therearound in the journal, a flexible diaphragm ring carried by said casing, sealing means on said diaphragm ring, a cooperating seal ring on said shaft, and means biasing said diaphragm ring to move the seal ring thereon against said cooperating ring.

8. In a drier drum construction having a hollow journal and a hollow shaft passing through said journal in spaced relation therefrom, the improvement of a seal casing carried by said journal, a pair of diaphragm rings in said casing, a seal on each diaphragm ring, cooperating seal rings on said shaft, said diaphragm and seal rings defining a seal space therebetween, and means for evacuating said space.

9. A drum constructioncomprislng a rotatable shell, hollow journals supporting said shell, stationary supports projecting through said journals, a steam heated basket in said shell carried by said supports, seals between the journals and supports including inner diaphragms adapted to be deflected by excess pressures in the shell to pass material from the shell, and pump means for recirculating the passed material to the heater and only partly filling the shell,'said shell having a vapor space therein, a safety blow-off device for relieving excess pressures in the vapor space, and means for supplying heating material .to said heater for volatilizing the heat transfer material around the heater. I

11. A drum construction comprising a rotatable shell defining an enclosed vapor space, a safety blow-off device for said space, means for filling said space with hot heat transfer vapors to heat the shell and condense on the shell into a liquid, and means in the shell for collecting said liquid in spaced relation from the shell. LLOYD HORNBOSTEL.

comprisinga rotat