US 1565772 A
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Description (OCR text may contain errors)
DRAINAGE SYSTEM Filed July 28. 1922 2 Sheets-Sheet 1 INVENTOR ATTORNEY w x M G. H. BARRUS Dec. 15, 1925- ,565. 72
DRAINAGE SYSTEM Filed July 28. 1922 2 Sheets-Sheet 2 Z6 1 L I l l l I K I l I K A ELSE 1 INVENTOR BY W M ATTORNEY i i anon-on a. mans, or noszromnnssncnusnms.
"situation .m afimy as, semi to." 578,034.
To all whom it may concern.- a.
Be it known that I, Gnonor. H. Banana, a citizen of the United States, residing at Boston in the county of Suffolk, State of Massac usetts, haveinvented certain new and useful Improvements in Draina e Systerns; and I do hereby declare-the fo lowing.
., and has to do artlcularly with a system in which the individual heating units are revolving drying cylinders of the type com-,
monly employed in paper making machines, and the like. More specifically, the-invention contemplates certain improvements and modifications in the structure disclosed in my United States Patent No. 1,192,369.
In machines of this character each of the revolving drying cylinders is commonly provided with ahollow bearing or trunnion through whichthe steam for heating the, drying surface of the cylinder is passed and also through which the condensate is-withdrawn from the unit. Two types of drainage systems for removing the accumulated condensate from the interior of the drying cylinders are in common use at present. In one of these systems, known as the bucket type, a plurality of scoops or buckets are secured to the inner wall of the d ing cylinder so that at every revolution .0 the; cyl
inder each bucket, during the lower ortion of its travel, takes up a quantit of t e condensed water and then empties it into a suitable trough or discharge passage during the subsequent ortion of its rotation. In the type of dralnagesystem known as the siphon system the discharge passa e for conveying the condensate out of t e drying cylinder assumes the form of a pipe enters ing the cylinder throughthe hollow trunnion and thence extending downwardly within the cylinder so that its open end is positioned a short distance from the cylindrical wall of the cylinder at its lowest point. This siphon'pipeis stationary and water may accumulate within the cy inder until the open end of the ipe is submerged. lVith this condition disc arge of the condensate will occur-provided that sufiicient ressure difference exists between the inrior of the cylinder and the discharge mainqto produce allow through the siphon P he bucket stem of drainage has the advantage that't e discharge flow isnot dependent at low speedson the presence ofa certain ressure difference between the interior o the cylinder and "the discharge main. However, the efiectiveness of the bucket system decreases as the speed of the drying rollers is increased due to the fact ,that the water condensate tends to accumulate at the outer walls of the cylinders under the action of the centrifugal force of rotation. "As a result, even. with moderate cylinder speeds, the water is" held by the ac t1on of centrifugal force in the buckets until the buckets are elevated, considerably above the axisof the cylinder. The time allowed for the condensate to run out is thus materiall diminished and-, 'in fact, this system of Y rainage may become entirely inoperative for high speed machines such .as arecommonly employed in the manufacture of aper.
6n the-other hand, with the si hon system the pressure required within t e drying cylinder to lift the water from the end of the siphon to the center of the hollow trunnion andestablish a lflow is often unavailable at the proper time and, as a result, water accumulates within the c linder to a considerable depth before a dlscharge flow is established. When the flow once starts it continues in considerable volume until the cylinder is em tied, whereupon the pressure within the cy inder is relieved due to the fact that the water falls below the opening in the siphon pipe and thus connects the interior of the cylinder directly with the discharge main. It is readily seenthat the drainage with the siphon system is likely to occur in gulps, and that moreover during that portion of the operation in which large quantities of water have accumulated within the cylinder the power required to turn the cylinders is greatly increased and the drying ca acity of the cylinders is correspondingly re uced. v
In neither. of the above typesof drainage is there any provision for the discharge of Lil air which ma accumulate in the drying cylinders and ecrease the heat transferring efficiency of'the drying surfaces.
One object of the invention is to prevent the accumulation of condensation water in the dryi-ng cylinder, and at the same time ma1ntaining an adequate pressure difference between the interior of the cylinders and the drainage main so that'a continuous outflow of the condensate will occur at alltimes. In this manner I reduce the amount of cow densate present within the cylinders at any time to a minimum, which quantity is determined by the distance of the opening at the inlet end of the siphon pipe from the adj acent portionof the cyhnder wall. Due to the continuous character of the (discharge the level of the condensate'is maintained at all times substantially flush with the opening in the siphon pipe and for this reason there is afi'orded ample opportunity for the accumulated air within the cylinder, together with a portion of the'uncondensed steam, to enter the siphon pipe and be conducted out of the cylinder. I also provide means for maintaining within each cylinder a pressure sufficient to maintain a substan mitting only condensed liquid to be dis-- tially continuous flow along the siphon pipe and into the discharge mam.
It is also an object of the invention to provide a heating system of this type in which the uncondensed steam issuing from the dry-- ing cylinders may be efiiciently and conveniently separated from the condensate in order that its available heat may be utilized in certain of the heating elements of the system, or in any other manner as desired.
It is a further object to rovide a system of the above type in whic the apparatus provided for separating out uncondensed steam from the liquid condensate and percharged from the system is inexpensive and of relatively small dimensions, so that the provision of a special pit or compartment for housing this portion of the system is not required."
It is a still further object to provide in connection with the heating system a single indicating element capable of registering the pressurejexisting in the various parts of the system so that proper operating conditions may be maintained, and to provide means by which the level of the condensate in the drainage system maybe determined in order that suificient space may be allowed It is applicable 'to for the uncondensed vapor to flow and t separate out.
t is a still further object to provide a system of this type an im roved elementof "simple, inexpensive an durable co'nstructionfor continuously mamtaming a suflicient pressure difierence between the interior of each drying cylinder and the drain age main to' insure a continuous discharge from thecylinder;
In the accompanying drawin I have illustrated a. drying apparatus 05 the revolving cylinder type embodying my invention. The apparatus shown is of the type commonly employed in paper mills. In the said drawings Figure 1 is a side elevational view showing the essential parts ofthe system; Fig.2 is a partial vertical transverse view; Fig. 3 is a detail view of a modified portion of the system; Fig. 4 is a partial side elevation, similar to Fig. 1, showinga somewhat modified system; and, Fig. 5 is a detail view of a portion of the apparatus. Referring to the drawings, 1 indlcates a drying cylinder positioned at one end of an apparatus comprising a plurality of cylinders, the remaining drying cylinders being indicated by the reference numeral 2. The cylinder 1 is preferably located at the Wet or initial end of the apparatus, although this arrangement is not essential to my invention. Each'of'the drying cylinders is rotatably mounted upon the frame of the apparatus and is provided with a hollow hearing or trunnion, as indicated at 3, and
through which extends the inlet and dis charge passages for the heating mediumsupplied to the cylinders. Steam from any suitable source is furnished to the supply main 4 and individual branch lines 5communicating with the main 4 serve to supply The pipe 6 enters the cylinder through the I hollow trunnion 3 and has its portion within the cylinder bent downwardly so that the opening at the inner end ofthe pipe rests -a short distance above the lowermost point of the cylindrical wall of the drying element. The condensate entering the siphon pipe 6 is conveyed out of thecylinder through the hollow trunnion 3 and into the main returu' be established within the cylinder, which back pressure will be sufiiciently .greatto -trate preferably, however, form the restricted pas-- establish and maintain a continuous flow through the siphon pipe 6 and discharge line 8 into the main return header 7. Te constricted portion 9 of the passa e .may simpl be a valve which is maintaine partly close or ma be a gate valve in which .a notchis cut or the purpose of'afiording a passa e of restricted cross section, as illusin 'my above-mentioned patent. I
sage 9 by means of a metallic disc having a centrally located orifice, as shown in detail in Fig. 9. This disc may be conveniently incorporated into the pipe line by inserting it at the junction between two lengths of pipe, as shown, thecross section of the fluid passage at that point being reduced in d1.
mension to the size of the orifice providedin the metal disc. A copper disc provided with such orifice gives excellent service under the conditions met in systems of .this t pe It is readil seen that inasmuch as the flow through t e orifice'can occuronly at a given rate by properly adjusting the dimensions of the orifice the pressure within each drying cylinder may be raised suffi ciently above that of the return header to insure a continuous discharge flow. Under such conditions the liquid level within the c linder will be maintained at substantially the level of theopen end of the siphon pipe 6, and not only will the condensate be continuously withdrawn from the cylinder but also a certain amount of the uncondensed steam together with the air accumulating within the cylinder will be discharged. For the purpose of protecting the constricted portion 9 of the discharge assage from becoming clogged by the gra ual accumulation of dirt, the orifice disc is pref-. erably inserted in the line 8 at a poin'tjust below a bend in the line, as shown at 10. The line 8 is extended somewhat past the elbow 10, as indicated at 11, so that whatever impurities issue from the cylinder will tend to continue on and accumulate in the bcumulate in the upper portion of the header 7, at the same time moving along the length.
of the header in a direction the same as that in which the liquid is flowing. At the outlet end of the header 7 there is provided a loop containing two adjacent lengths of vertical piping 12 and 13. The liquid condensate in the return header flows down into its lesser specific gravity, tends to continue on beyond the jIunction of the pipe 12 with the header 7 hus an effective separation of. the vapor from the liquid is accomplished by the influence of gravity alone and the vapor passes up throu h the line 14 and serves as a heating me 'um for the drying cylinder 1, after which it is dischar ed in the manner above described through t e line 8? into the pipe 15 leadin to the hot well or other place ofdisposal or the liquid condensatej The vertical loop consisting primarily of the lengths of piping 12 and 1-3 is rovided for the purpose of permitting only liquid condensate to pass into the line 15 leading to the hot well, and to cause all the uncondensed vapor to pass up through the supply line 14 into the drying cylinder 1. In apparatus of this type as sometimes'constructed the vertical arm 13 of the loop is made appreciably lon erthan the arm 12 so that the additiona height of the water column in the arm 13 will be sufiicient to compensate for the excess, of pressure existing in the return header- 7 over that which exists in' line 15 leading to the hot well. This type of construction is, however, objectionable in that it is not'uncommon for the pipe 13 constituting one side of the loop to reach a length as great as feet, or where both are of the samelength, to extend into the the vertical pipe 12 wliile the vapor, due to ground that extreme distance. It is obvious that the provision of a pit or other place of disposal for such agreat length of vertical pipe results in a great deal of additional expense in the installation of the apparatus. To overcome this difiiculty I have constricted a portion of the passage in thepipe 13 in such manner that by means of a constriction ,a backpressure may be established upon the liquid endeavoring to flow up through the ipe 13 which pressure is the equivalent of that ordinarily supplied by the additional weight of the water column provided in an elongated arm 13. This constricted passa may consist merely of a valve providedm the pipe 13, but for the purpose of adjustment I preferably provide an open pipe 16 of cross section smaller than that of the pipe 13 and discharging into the line 15 leading to the hot well. A certain constant portion of the condensate is thus free to take the shunt passage directly through the open pipe 16. A valve 17 is provided in the line 13 above its juncture with line 16 and may be utilized when neccssary for the purpose of regulating the flow of that portion of the condensate which is not accommodated by the pipe 16. By this construction the regulation affects only a fraction of the total volume of flow andmay thus be conducted with greater facility than would be the case if the entire fluid stream were controlled by the regulating valve."
floor upon which the drainage system is mounted. The condensate will normally stand at a level somewhere along the pipe 12, and this level may be varied byopening the valve 17 to a greater or lesser extent. For the purpose of determining approximately where the level of the condensate in the p1pe 12 is located a series of testcocks 18 is provided, the'upper'most of the cooks which discharges ,water upon I opening indicating that the liquid level is somewhere between that cock and the one next above.
It may be noted that'the inner ends of the it is merely necessary to turn on the supply of steam to the main header 4, and the operation of the apparatus continues automatically. I have found that the copper discs containing the orifices may be continu-- ously used without the necessity of varying the size of the orifice, and the proper,
size of orifice may be initially determined by experiment. termination it will not subsequently be necessary to change the size of orifice'em-, ployed although such a change may readily be made merelyby substituting a disc having a different sized-hole. I have found that the copper discs containing the orifice are'more satisfactory than gate valves with a notch portion of the passage, inasmuch as valves are apt to be tampered with and the adjustment of the system thus disturbed. F urthermore, the provision of the orifice discs affords a less expensive and a more rigid and less complicated structure.
For convenience in determining the pres sure in the various parts of the system, I provide a gauge 19 preferably capable of registering pressures either above or below atmospheric, and arrangeconnections to the gauge insuch manner that the pressure at any part of the system may be determined. For instance, when the valve 20 in the gauge piping is open and the valves 21 and 22 are closed the gauge will register the pressure in the main steam header. \Vith valve. 21 open and the other valves closed the pressure indicated by the gauge is that in. the return .means of an open After such initial deheader 7, while with valves 21"and 20 both closed and valve 22 oplen the pressure in the line 15 leading to the ot well is determined.
*In this manner it is possible to determine in a few .seconds whether .there is sufiicient pressure difference between the drying c l-' inders and the discharge main and whether there is the proper pressure difference between the discharge main and the line 15 to secure a free flow to the hot well.
In Fig. 3 I have illustrated a modification in which the vertical pipe loop is disgensed with. In this modification the conensate from the return header 7 flows down into the short vertical pipe'or chamber 23 and is conveyed thence into the discharge' line 15 leading to the hot well partly by pipe 24 and partly byv means of a trap 25. The larger roportion' of the condensate passes through pipe .24 35 whilethe trap serves to regulate the balance.v It is to be noted that this arrangement is more satisfactory than would be the case where the open line 24 is dispensed with and the trap employed alone, for the reason that in the arrangement shown the size of thetrap may be materially smaller and the expense of the system correspondingly reduced. It may be of advantage to substitute the tra .25.and its associated pipe 24in place 0 the vertical loopwhen the s ace beneath the apparatus is particularly imited, as only a small space is required to accommodate the, trap.,
In Fig.4 I have illustrated a 'further manner in whichthe steam recovered from the return header 'Z'may be utilized. A heating employed to convey steam to any desired for the purpose of forming the constricted,
po nt for utilization in whatever manner.- may be desirable, or the steam may be partially 'usedto heat one of the drying cylinders and partly for any other appropriate purpose. 1
I have described certain preferred embodiments of my invention, but it is possible that certain variations and changes may be made without exceeding the scope of the invention as defined in the claims. For instance, the cylinder 1 in which is utilized the steam recovered from the main return header need not be located in the position shown but mayv be any one of the heating elements of the systems. It is further to be understood that while I have described my invention asemployed in connection with a system of the type ordinarily employed in paper mills, it is equally applicable to any installation in which revolving drying cylinders areemployed, such as thoseused in textile mills for drying cloth, and the like.
1. A system of the class described, comprising a plurality of drying cylinders, means for supplying heating steam to said cylinders, means for removin the contents of said cylinders comprising a drainage main and individual drainage connections between the respective cylinders and said main, and means for maintaining a continuous pres sure difference between the cylinders and said drainage main comprising a restricted portion of constant area interposed in each of said individual drainage connections.
2. A system of the class described comprising a drying cylinder, means for supplyin heating steam to said cylinder, means for e ecting a discharge from said cylinder comprising a drainage line and connection from the cylinder to said line, and an obstruction in said connection containing an orifice of fixed dimension whereby the flow through said connection is restricted and the pressure in said cylinder raised above that in said drainage line.
3. A system of the class described comprising a plurality of drying cylinders, means for supplying heating steamto said cylinders, means for effecting a discharge from said cylinders comprising a drainage main and individual drainage" connections between the respective cylinders and said main, means for maintaining a continuous pressure difference between the cylinders and said drainage mainlcomprisin a metallic disc containing an orifice of xed dimension whereby theflow through said drainage connections is restricted.
4. A system of the class described comprising a plurality of drying cylinders, means for supplying heating steam to said cylinders, means for efiecting a discharge from said cylinders comprising .a drainage main and individual drainage connections between the respective cylinders and said main, means for maintaining a continuous pressure difierence "between e cylinders and said drainage main, means for se arat ing the condensate from the uncon ensed va or in saidlnain comprising a passage for de ecting the condensate out of its previous direction of flow and a separate assage for' receivin the vapor, and means or conveying sai uncondensed vapor to a point of utilization.
5. A system of the class described, c0mprising a plurality of drying cylinders, means for supplying heating steam to said cylinders, means for removin the contents of said cylinderscomprising a raina e main and individual draina e connections tween the respective cylin ers and said main, means for maintaining a continuous pressure difference between the cylinders and said drainage main, means for separating the condensate from the uncondensed vapor insald main comprising a downwardly extending r passage for receiving the condensate, where by the condensate is deflected by the action of gravity from its previous direction of flow and a separate passage for receiving the uncondensed vapor without altering its age connections between the respective cylinders and said main, means for maintaining a continuous pressure difference between the cylindersand said main, means for separating the condensate from the uncondensed vapor in i saidmain comprising a passage for deflecting the condensate out of its preplying said uncondensed vapor as heating medium to the remaining cylinders.
' 1?. A system of the class described comprising a plurality of drying cylinders, means for supplying .heating steam to a number of said cylinders, means for removing the contents of said cylinders comprising a drainage main and individual drainage connections between the respectivecylinders and said main, means for maintaining a continuous pressure difference between the cylinders and said main comprising a restricted portion of constant area interposedin each of said individual drainage connections, a passage 'at substantially the outlet end of said drainage main for deflecting the condensate away from the uncondensed vapor, a passage for receivng the uncondensed vapor and conveying it "into the remaining drying cylinders as heating medium therefor, and means for effecting a continuous discharge therefrom.
8. A system of the class described comprising a plurality of drying cylinders, means for supplying heating steam to said cylinders, means for effecting a discharge from said cylinders comprising a drainage main and individual drainage connections between the respective cylinders and said main, a loop passage for. receiving and discharging the condensate from said drainage main, one branch of sad fluid conveying loop having a portion of restricted cross section for impedirig the flow of fluid therethrough.
9. system of the class described comprising a plurality of drying cylinders, means for supplying heating'steamto said cylinders, means for effecting a discharge from said cylinders comprising a drainage main and individual drainage connections between the respective cylinders and said main, 'a vertical fluid conveying loop for-revious direction of flow, and means for supceiving the condensate from said drainage main, the latter branch of said 100 being of restricted cross section for retar ing the flow of fluid therethrough, whereby a loop of maximum dimension comparable wit ceiling height may be employed to balance the pressure in said drainage maln. r 10. A system of the "class described comprising a plurality of drying cylinders, means l for supplying heating steam to-said cylinders, means for effecting a discharge from said cylinders comprising a drainage main and individual drainage connections between the respective cylinders and said main, a loop passage for receiving and discharging the condensate from said drainage main, the initial branch of said loop being of substantially uniform cross section and 'the latter branch of said loop having a portion of restricted cross section less than that of the unrestricted portion of said latter branch, whereby a portion of the condensate is discharged through said shunt passage and' the remainder through said restricted portion, and means for varyin the fluid conveying capacity of said restricted portion.
I 11. A system of the class described comprising a plurality of. drying cylinders, means for supplying heating steamto said cylinders, means for efi'ecting a discharge from said cylinders comprising a drainage main and individual drainage connections between the respective cylinders and said main, a loop passage for receiving and discharging condensate from said drainage main, the latter branch of said loop having a portion of restricted cross section for impeding the flow of fluid therethrough, and a plurality of test cocks provided on the initial branch of said loop, whereby the approximate level of the condensate in said initial branch may be determined.
12. A system of the class described, comprising a plurality of drying cylinders, means for supplying heating steam to said cylinders, means for effecting a continuous discharge from said cylinders comprising a drainage main and individual drainage connections between said respective cylinders and said main, means for maintaining a continuous pressure difference between cylinders and said drainage main, comprising a restricted portion of constant area interposed in each of said individual drainage connections, a loop passage for receiving and discharging the condensate from said drainage main,- the initial branch of said loop being of substantially uniform cross section and the latter branch of said loop havin a portion of restricted cross section, a s unt passage around said restricted portion of cross section less than that of the unrestricted portion of said latter branch, whereby a portion of the condensate is discharged through said shunt passage and the remainder through the said restricted portion, and means for varying the fluid conveying capacity of said restricted portion.
A system of the class described, comprising a plurality of drying cylinders, means for supplying heating steam to said cylinders, means for removing the contents of said cylinders comprising a drainage main and individual drainage connections between the respective cylinders and said main, means for. maintaining a continuous pressure difference between the cylinders and said drainage main comprising a restricted portion of constant area interposed in each of said individual drainage connections, a pressure gauge, and connections whereby said pressure gauge may be caused to register the pressure within the drying cylinders, in the drainage main, and in the discharge line, respectively.
In-testimony whereof I aifix my signature.
GEORGE H. BARRUS.