US2297094A - Drainage device for web drying machines - Google Patents

Description

Sept. 29, 1942. A. 5. ARMSTRONG ETAL 2,297,094

DRAINAGE DEVICE FOR WEB DRYING MACHINES Filed July 5, 1940 INVENTOR 4 Zfida7f,%r/m/m/g7 BY 2% 7 a Q4/7- romimys Patented Sept. 29,1942 a UNITED ,S'l ATE s- PATENT OFFICE DRAINAGE nsvrcs son was narma mcnmss Adam it. Armstrong and Fred A.

assignors to Works, Three Rivers, Mich.

Application July 5, 1940, Serial No. 344,024- 18 Claims. (01. 34-424) Rivers, Mich,

slowly.

Third, to provide a siphon type drainage device for web drying cylinders, which is well adapted for association with automatic temperature or pressure devices, whereby the latter are "accurately responsive to variations in the temperature at the periphery of the cylinder.

Fourth, to provide a novel steam supply and drainage device for a drying machine cylinder having provision for efiectively preventing the entry of air into the cylinder, particularly in cases where a vacuum condition exists inside the cylinder.

Further objects mies of our invention will appear from, the description to follow. The invention is defined in the claims. a

A structure embodying the features of our invention is illustrated in the accompanying drawing, wherein:

Fig. 1 is a fragmentary view broken away and in vertical axial section through a drying cyl- "inder or drum illustrating the novel provisions of our invention associated with the drum for the purposes referred to above.

Fig. 2 is a view in section on line 2-2 of Fig. I, particularly illustrating the structure and arrangement of certain" of the parts.

Fig. 3 is a fragmentary view in section on line 3-3 of Fig. 1, further illustrating certain of the condensate drainage provisions constituting a partof the present invention.

In general, thesubject matter of the present application relates to a drainage system for paper or web drying machines and more particularly to machines of this type which include a. siphon tube extending radially oi the drying cylinder or drum and rotating with the latter.

In machines of this type, wherein the drums are rotated at high surface speeds, i. e., in excess relating to details and econo- Thor, Three n; Machine force against the periphery of the drum or cyl.- inder. It is common practice to utilizesiphon tubes for removing condensate; However, at

high 'speed unlesslarge amounts of steam at a high differential in pressure between the drum and the siphon tube-are employed to" sweep the condensate fromthe'interior of the drum into the siphon tube, it is hardto remove the same and the use of such high differential requires 'a large amount oi steam and is very wasteful.

. One aspect of our invention relates to novel means for overcoming this diflisculty, so that the drum or cylinder may be eilectively drained in an economical manner.

A further refinement of the invention relates to a device associated with the siphon tube to render its action more effective when the drum or cylinder is operating at a'lesser surface speed, at which speed the centrifugal force exerted on the condensate is notv so great as at higher speeds. The aforesaid refinements make possible the removal of large quantities of the condensate under these conditions.

A still further phase of our invention relates to the provision of a novel combination of a rotary seal between the siphon tube and the fixed steam. supply chamber or chest, with means for preventing the admission of atmospheric air to the said chest and interior of the drum in the event that the latter is being operated under a vacuum condition; This is particularly important in cases where an automatic supply of; steam is contemplated, in which case the.

presence of air in substantial quantities inside of'the cylinder or drum would render the functioning of the automatic steam supply means imccul'ate and undependable. Furthermore, the

siphon tube is of a novel insulated construction which particularly adapts the same ioruse in connection with an automatic supply device of the general type described, wherein it is desir-able to control certain instrumentalities by the temperature of the drum interior' immediately adiacent the periphery thereof. A siphon tube of the particular type herein shown and described makes it possible to take a sample of the steam at this point and apply it to temperature and pressure responsive instrumentalities for the purpose of eilecting an automatic of 700 ft. and up to 1300 ft. per minute, diiilculty has been experienced in. effectively remov-v control of the temperature of the drum without inaccuracies creeping in which would render the whole operation unsatisfactory. In a drainage of the rotating siphon type, such provisions are invaluable.

Referring to the drawing, reference numeral I indicates a drum or cylinder of a rotary web apnoea machine. This end of the drum is provided with a suitable-closure l clamped in place and the other end thereof has steam admission open- 1 8 formed therein adjacent the axis and communicating with a steam admission box 6 integral with the end of the drum and journaled on frame 3 by means of a ball bearing 1.

The reference numeral 8 indicates a fixed steam supp y chest or chamber which is supplied with steam, through a suitable tapped ada smallsquare or circular sumpor depression 20 into which the tip 2| of the siphon tube projects. This is much more effective than any possibleattempt to space the tip of Qthe tube ex-' tremely close to-the front surface, for it allows a considerable area of opening between the drum surface 'and siphon tube into which the condensate may flow. Since the tip or end of the 7 tube lies at a greater radial distance-from the mission port 8. The steam may be supplied at pressure greater or less than atmospheric. A

further tapped opening 9i axially of the chest is employed for connecting the drainage device to be described with automatic steam supply instrumentalities which, per se, constitute no part of the present invention, hence have not been illustrated; I

Communication of the interior of the drumJ with the fixed steam supply chamber 8 is established through a hollow, elongated sleeve-like sealing member i0 constituting one of -a pair of such sealing members, the other of which is designated by the reference numeral ll. These sealing members have oppositely facing founded drum axis than the inner drum surface and since the sumnfllls with water under the influence of centrifugal force, the extremity of the tube at all times extends into this condensate and the removal thereof is accordingly greatly facilitated.

The foregoing structure is very eflective in removing condensate during the web drying operation when the drum or cylinder I rotates at high speeds. However, when the speed of the drum is less, for example, approximately 500 ft. per minute, inasmuch-as the centrifugal force is less, the condensate tends to flow downwardly from the drum. walls and collect at the bottommost point of the rotating drum. Under such conditions, the rotating siphon tube would normally pass through the collected water at the bottom of the drum only once per revolution,

" and as the sump 20 travels'upwardly, the conor convex surfaces l2 coacting with suitable "sealing or packing rings it of graphite orother suitable material. These packing rings have the mutually facing concaved or curved surfaces It coacting with the convex surfaces l2 of the seal-' ing members. The compression spring I! is interposed between the members In and II. It will be observed that member in is threadedly connected to the steam admission box 6 of the drum, hence rotates therewith. The" other sealing member II also rotates with the drum, and a fluid-tight seal is eflected at the coacting meetpassages and serving to center spring IS.

The sealing member ii has secured thereto one end of the L-shaped siphon tube, which is generally designated by the reference numeral II. The particular construction of this tube will be referred to in detail. However, for the present it is suflicient tostate that it is secured tothe sealing member H by threading at l8 and is associated with an apertured disk I 9 concentrio with the sealing member and secured thereto by screws. This disk has a conical axial projection which extends into one extremity of the siphon tube, for a purpose to be described.-

The opposite end or radial portion of the L-shaped siphon tube extends adjacent the periphery of drum l for removal of condensate therefrom. Previously, it has been proposed to blow steam condensate out through the tube by steam under pressure inside of the drum. How-. ever, as pointed out above, this practice is very wasteful and costly, since in a drum running at high surface speeds, say from 700 ft. per minute to 1500 ft. per minute, the condensate is thrown against the drum periphery with considerable force, so that it is very dimcult to remove it I tremity of the siphon tube.

siliently urged against the inner drum peripherydensate would be drawn out from the same so that for a great portion of the revolution there would be no condensate adjacent the siphon tube. To remedy this objection, we have provided an auxiliary scoop or dam element generally designated 22, in the form of a sheet metal member having an aperture 23 receiving the ex- The scoop is reby means of a coil spring 24 which encircles the 4 tube, engaging the scoop 22 at one end and a 7 ing surfaces l2, ll" of themembers and rings thrust ring 25 on the tube-at the other end. The

' scoop is clearly illustrated in Figs. 1 and 3, having spaced side walls 26, a top'wall 21 spaced a predetermined distance from the drum periphery, and a rear wall 28. The advance side or front of the scoop is open in the direction of rotation of the drum.

Assuming that the drum rotates in the direction indicated by the arrow in Fig. 3, the dam element operates to trap a quantity of condensate and maintain the same in the vicinity of sump 20 as the sump passes the lower-most point of. its

travel and begins to ascend. Thus, this condensate is retained adjacent thesump to keep the same filled during a large portion of the upward travel of the drum, for example, approximately two-thirds of the vertical dimension of the drum. By this expedient, immersion of the siphon tube extremity in the condensate is maintained through a much longer period, with the result that the tube continues to siphon condensate from the drum interior instead of merely siphoning steam, and the drainage of the drum is greatly enhanced.

In certain drainage systems, we have found it desirable to utilize a small boiler filled with a volatile liquid which is adapted to be heated to the same temperature as the interior of the drum immediately adjacent the periphery thereof. Such an element, associated with a siphon tube of the stationary type, is illustrated in the copending application of Adam E. Armstrong, Serial No..353,270, filed August 19, 1940. How- I ever, when a rotating-type siphon tube is emhave provided the periphery of the drum with ployed, it is impractical to mount the boiler element on or adjacent the tube, as illustrated in the aforesaid application, and it becomes necessary to dispose the same exteriorly of the drum. If-this is done, however, a possibility for error is introduced, because of the fact that the interior of drum i is not always at the same temperature and led radially and outwardly of the drum, this steam would become heated, above the tempera-- ture actually present at the drum periphery, so that by the time it reached the boiler element. it

in: box by. friction or secured thereto by other means. if desired. The other end of the hollow spring element ll carries a graphite sealing ring ll generally similar to the rings II, which is resiliently urged by the bellows spring element against the exterior or the chamber I. Since the sleeve 38 of the rotating would be at a higher temperature than the correct periphery temperature.

' To enable accurate operation of an acetone boiler element. such as we have described, or other control device, we therefore provide a spemade up of two outer pipe sections ll, 2., disposed horizontally and, radially respectively and connected by the special elbow II. The pipesections 2!, 28 have disposed interiorly and concentrically thereof the tubes 3| which are flared. at the ends thereof, as indicated by the reference numeral I2, and connected to the pipe sections 22!, by'welding-ij. The space'between the tubes 3| and the pipe sections 2|, 2! respectively is evacuated of airi-prior to completion of the members, thereby producing a pair of insulated conduit members similar in their insulating properties to the well known thermos bottle. As described above, the section 28 of the siphon tube ii is threadedly connected to the sealing member ii and the'two sections 28, 29 are threadedly connected with the special elbow 3|, thereby constituting the L-shaped siphon tube I1. Elbow 33B likewise has vacuum type insulating provisions in the form of an evacuated space 34, so that heat transmission through the wall of the element at this point is avoided.

By the foregoing provision, steam taken from the periphery of the rotating drum is transmitted to the temperature responsive boiler or other control element referred to without being reheated by the hotter gases-adjacent the center of the drum. The resultis that its action on the element corresponds accurately to the action which would be exerted by the steam if the element were disposed immediately adjacent and interiorly of the drum periphery. I

In many instances. it is desirable to operate a drying drum of the type described under a vacuum condition and in such cases it is also desirable to prevent the uncontrolled admission of atmospheric air to the interior of the drum. This is likely to;happen, particularly over a long period dfoperation and where relatively fixed and roclal type thermally insulated siphon element l1 sealing member it extends through the aperture ill in chamber l with considerable clearance, in order to enable possible misalinement of the housing and the drum to be accommodated, the space ll between the resilient bellows member I! and the elongated sleeve 8! is in communication with the small space in chamber immediately to the right of the aperture I, as illustrated in Fig. 1. Assuming a vacuum condition, 1. e., less than atmospheric pressure, to exist in the drum and steam chamber I, it is evident that were no precautions taken, there would be a tendency for atmospheric air to leak between the sealing ring it and either the surface of the chamber 8 or the surface II of the sealing member with which the same coacts, likewise that the same possibility of leakage would be present between the rotating ring 81 and the exterior of. the chamber 8. In order to eliminate such possibility, we provide an opening ll in the wall of chamber or chest 8 communicating with the space 38, being preferably formed in the casting from which the chest is made and extending to the aperture 38!. This opening is provided with a tapped outlet adapted to be connected to a source of water or steam at a result that if any air or other vapor were to enter the space II, it would be drawn out by the vacuum source and would not enter the Theforegoing construction features all con- .tribute to a drainage system which is highly efiective in operation, to the production of a drying element of high thermal efllciency and to a steam control which is very accurate and reliable. Whether operating at high or low speeds, the amount of condensate drained from the drum is increased without the use of high differential pressures and amounts of steam and the entry of air to the drum interior is prevented. It is possible at all times to get an exact indication of the temperature of the vapor at the drum periphery,

by which the need for further regulation of the 'drum temperature must be ascertained, if accuracy of control is to be had. In view or the manifold improvements made possible thereby, the structure of the present invention is exceedingly simple and inexpensive and moreover may tatable sealing members are present, and if it does, the resultant mixture of air with the ste in the drum causes unreliability in the control 0 the temperature of the drum. since the temperature can no longer be predicted from the drum vapor pressure. v

In order to prevent the admission of air to the drum, we provide an exterior sealing element for the connection between the rotating steam admission box 0 and the fixed steam chamber or chest l in the form of a spring bellows member it which one end thereof and fixedly engaging the rotathas a ring-likecoupling element ll secured to be, readily applied to existing drying drums.

We have illustrated and described our improvementsin an embodiment which is very practical.

we have not attempted to illustrate 'or describe other embodiments or adaptations as it is believed this disclosure will enable those skilled in the art to embody or adapt our improvements as may be Having thus described our invention, what we claim t laas new and desire to secure by Letters Paten 1. In a drainage system fora drying cylinder, an insulated double walled siphon tube extending steam admission radially and axially of said cylinderand rotating relation to the tube and engaging said cylinder for collecting condensate during the rotation of the cylinder and maintaining condensate in the.

vicinity of said sump, spring means for resiliently urging said scoop element against the cylinder periphery, a fixed steam admission housing, a sealing element concentric with the axial portion of said siphon tube. having a sealing surface in said housing and a portion extending through an aperture in the housing and fixedly connected to the cylinder for rotation therewith, said sealing element being hollow tor the purpose of transmitting steam from said housing to the interior oi said cylinder, a further sealing element coaxial with and connected to said axial portion of the tube for rotation therewith, spring means interposed between said sealing elements to urge the same axially in opposite directions, sealing rings interposed between said sealing elements and the respective opposite walls of the housing whereby to provide seals between the housing and the rotating sealing surfaces of said elements, and means for preventing the admission of atmospheric air to said housing.

interposed between said sealing elements and the housing whereby to provide seals between the housing and the rotating sealing sun'aces oi said elements, and a steam supply connection to said housing supplying steam thereto at a point between said ,sealing elements, the interior of said first named hollow sealing element communicating' with the housing at said last named point. e

4. In a drainage systemgtor a drying cylinder, an insulated siphon tube extending radially and axially oi! said cylinder and rotating therewith,

the radial extremity of said tube being adjacent the periphery of the cylinder and said periphery 2.- In a drainage system for a drying cylinder, I an insulated siphon" tube extending radially and axially of said cylinder and rotating therewith,

the radial extremity of said tube being adjacent the periphery of the. cylinderand said periphery having a sump into which said extremity extends, a scoop element mounted on said tube and having side and rear walls in spaced relation to thetube and engaging said cylinder for collecting condensate during the rotation of the cylinder and maintainin condensate in the vicinity of said sump, spring means for resiliently urging said scoop element against the cylinder periphery, a fixed steam admission housing, a sealing element concentric with the axial portion ot said siphon tube, having a sealing surface in said housing and a portion extending through an aperture in the housing and fixedly connected to the cylinder'tor rotation therewith, said sealing elementbeing hollow for the purpose of transmitting steam from said housing to the interior of said cylinder, a further sealing element coaxial with and connected to said axial portion oi! the tube for rotation therewith, sprin means interposed between said sealing elements to urge the same axially in opposite directions, and sealing rings interposed between said sealing elements and the housing whereby to provide seals between the housing and the rotating sealing surfaces of saidelements.

3. In a drainage for a'drying cylinder, 9. siphon tube extending radially and axially of said cylinder and rotating therewith, a fixed steam admission housing, a sealing element concentric with the axial portion of said siphon tube, said element having a sealing surface in said housing and an axial portion extending through an aperture in the housing and fixedly connected to the having a sump into which said extremity extends,

a scoop element mounted on said tube and having side and rear walls in spaced relation to the tube and engaging said cylinder for collecting condensate during the rotation of thecylinder and maintaining condensate in the vicinity of said sump, and spring means for resiliently urging said scoop element against the cylinder periphery.

5. In a drainage system for a drying cylinder,

,a siphon tube extending radially and axially 0! inder periphery adjacent the tube.

6. In a drainage system for a web drying drum, a siphon tube txending radially and axially of said drum and rotating therewith, said tube havhaving a sump into which said extremity extends,

a scoop element mounted adjacent said tube and engaging said drum for collecting condensate during the rotation of the drum and maintaining the condensate in the vicinity 01' said sump, means for maintaining said scoop element against the drum periphery, a fixed steam admission housing, a sealingelement concentric with the axial portion of said siphon tube, said last named element having a sealing surface in said housing and a portion extending through an aperture in the housing and fixedly connected to the drum for rotation therewith, means for transmitting steam from said housing to the interior of said drum, a

further-sealing element coaxial with and connected to said axial portion of the tube for rotation therewith, means interposed between said sealing elements to urge the" sealing members axially in opposite directions into sealing relation to the housing. and means coacting with said sealing elements to seal the housing.

- '7. In a drainage system for a web drying drum, 9. siphon tube extending radially and axially of said drum and rotating therewith, a fixed steam admission housing, a sealing element externally concentric with the axial portion of said siphon tube, said last named element having a sealing surface in said housing and a portion extending through an aperture in the housing and fixedly connected to the drum' for rotation therewith,

- said sealing element being hollow and commumeeting with the drum interior for transmitting and maintain the extremity of steam f om said housing to the interior of said drum, a iturther sealing element coaxial with and connected to said axial portion of the tube for rotation therewith, means interposed between said sealing elements to urge the sealing members axiallyin opposite directions into sealing relation to the housing, means coacting with said sealing elements to seal the housing, and a steam supply connection to said housing supplying steam thereto at a point between said sealing elements, the interior of said first named hollow sealing element communicating with the housingat said last named point.

8. In a drainage system fora web drying drum,

, a siphon tube extending radially and axially of I supplying steam thereto, a siphon tube for removing condensate from the drum and adapted to rotate with said drum, comprising radial and axial double walled insulated pipe sections having means communicating the same, said tube being connected to the drum for rotation therewith, said drum having a sump in the wall thereof into which said radial portion extends, whereby to collect condensate during high speed rotation of the drum and maintain the extremity of the ra-' dial portion immersed therein, a scoop element carried by said radial portion and having a wall in spaced relation to said portion and sump serving to collect and maintain condensate adjacent the sump as the drum rotates at slower speed whereby the extremity of the radial portion is maintained in condensate in the sump for a relatively large portion of its upward travel, and spring means coacting with said radial portion and scoop element to resiliently urge the latter against the drum wall.

10. In a rotating drying drum having means for supplying steam thereto, and a siphon tube for removing condensate from the drum and adapted to rotate with said drum, comprising radial and axial double walled insulated pipe sections having means communicating the same, said tube being connected to the drum for rotation therewith, said drum having an annularlv restricted sump in the wall thereof in general radial alinement with the tube into which said radial portion extends, whereby to collect condensate during high speed rotation of the drum and maintain the extremity of the radial portion immersed therein.

11. In a rotating drying drum having means for supplying steam thereto, and a radially extending siphon tube for removing condensate fromtl'ie'drum and adapted to rotate with said drum, said drum having an annularly restricted prising an insulated siphon tube radial and axial portions, said tube comprising an outer hollow section and an inner hollow section disposed concentrically of the outer section to deline a space therebetween, air being evacuated from said space and the ends of said sections ueing secured together to hermetically seal the same and increase the efflciency of the tube as a ther: mal insulator, whereby tmprevent reheating of steam traversing tbs tube from a point adjacent the inner periphery of the drama to the exterior of the drum.

13. A drainage system for a rotating drying drum comprising a fixed housing for supplying steam to the drum, said housing having a steam inlet. an open ended hollow siphon tube having portions disposed radially and axially of said drum and adapted to rotate therewith, a hollow,

steam transmitting memberhaving a sealing element and a sleeve-like portion coaxially secured to said drum for rotation therewith and internally receiving the axial portion or said siphon tube, the space between said element and axial portion constituting a steam admission passage in communication with ths interior of the housing and drum, a further sealing element connected to said axial portion for'rotation therewith, said elements being disposed within said housing and said; sleeve-like portion extending through an opening in one of the housing walls, there being a further opening in the housing receiving condensate drainage means in communication with said siphon tube, sealing means disposed in said housingbetween the housing walls and the respective elements, and means for urging the elements and sealing means in opposite directions \against said walls whereby to fluid seal the housing at said openings from the escape of steam therethrough. t

14. In a steam supply device for a rotating drying drum, a steam supply housing for supplying steam to the drum, a hollow sealing member carried by said drum disposed interiorly of said houssump in the wall thereof in general radial alinement with the tube into which the radial portion thereof extends, whereby to collect condensate during high speed rotation of the drum the radial portion immersed therein.

12. In combination with a rotary drying drum, a condensate drainage system for said drum coming adjacent an opening therein and cgacting therewith to fluid seal the housing at are opening, said member communicating the housing with the drum, and means for preventing the admission of atmospheric air to said housing and drum when the latter is operated under a vacuum condition, comprising a hollow member secured concentrically of said first named member to the drum for rotation therewith and having a sealing element in rotatable thrust engage-'- ment with the exterior of said housing adjacent said opening to thereby define a space in communication with said housing opening and the exterior side of said first named sealing member, and means for communicating said space with a source of fluidunder pressurejreater than atmosphere or with a source of vacuum greater than the vacuum condition in the housing and in the housing for communication with the drum interior, sealingsurfaces disposed within said housing and connected respectively to said element and siphon tube, said surfaces coacting with further sealing means in the housing to seal the same, means for maintaining said element and v last named means in operative sealing engagement, means for supplying steam to the housing at a point between said surfaces, and condensate drainage means connected to the housing on the side of said surfaces remote from the drum ina communication with said siphon tube.

16; Steam supply means for a rotating drying drum, comprising a fixed steam chest, a member having a sealing portion disposed interiorly of said the drum having sealing engagement with saidfixed chest and defining a space surrounding said axially extending portion and in communication with the chest opening, and means for com municating said space with the source of fluid "pressure greater than atmospheric or, with a source of vacuum whereby to prevent admission or maintenance of air in said space.

17, Steam supply means for a rotating dryln drum, comprising a fixed steam chest. a member having a sealing portion disposed interiorly of said chest and a portion extending through an opening in the chest axially 01' said drum and fixedly secured to the drum for rotation therewith/said member being hollow in its interior and communicating the'chest with the drum interior,

means coacting with said sealing portion for providing a rotatable seal for the chest'adjacent 2 said opening, and means for preventing the ad- 40 mission oi air to the chest and drum particularly when the latteris operated at less than atmospheric pressurercomprising/means having sealing engagement with said drum and chest and defining a space surrounding said axially extending portion and in'communicatio'n withthe chest opening, and means for communicating said space with a source of fluid pressure diflerent in niagnltude from atmospheric, whereby to prevent admission or maintenance of air in said space.

18. In a drainage system for a rotating drying drum having a steam supply housing tor supplying steam thereto, a siphon tube extending from said housing into said drum, a sealing member carried by said drum and disposed interiorly of said housing, 'the sealing "member having a hollow sleeve-like portion concentrically receiving the tube attached to the drum and extending through an opening in the housing for passage of steam from the housing to the drum,

said member coacting with ,said housing to fluid prevent the seal the latter at said opening, and means for preventing the admission of atmospheric air to said housing and drum when the latter is operated under a vacuum condition, comprising a hollow bellows spring member enclosing said sleeve like portion and secured to the drum for rotation therewith, said last named member having a sealing ring rotatably engaging the exterior oi said housing to thereby define a space in communication with the housing on the exterior side of saididrum carried sealing member, and means for communicating said space with asource oi fluid under pressure greater than atmosphere 'or' with a source of vacuum greater than the vacuum condition in the housing and drum, whereby to entry of air'in said space.

i E. ARMSTRONG.

FRED A. THOR.

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