US1810371A - Labyrinth gland packing - Google Patents

Description

` June 16, 1931. A K. BAUMANN 1,810,371

LABYRINTH GLAND PACKING Filed ApI"i1- 13, 1928 95.11 a4 m I K' Fuga. .Ll

WITNESS F|', 5. INVENTOR Karl Baumann BY ATTORNEY Patented June: 16, 1931 Knnrignnunnnn, orlnnifrsron, nNGri-innfnssrenon ro Wnsrrfnenousn- Erncrnrc a" tslwt;

rarest orrics yMAn,Urncfrunine ooMiANY, Av CORPORATION Der yrn nirsizmznnia Application niearaprn 13,v 1928seriai-no. 269,816, and` in Great B-raamnprii as, 19,27."Y

The invention'relates toilabyrinth gland.

packingl for usey between relatively movable parts of a machineV as for instance, vbetween aturbine shaft and the part of a Aturbine casing through which yit apassesf; y

that the contiguous packing members auto-.-

niatically tend to separateif; rubbing occurs therebetween, asis'obtained byfpackings such as. described in myPatent 1,708,044, granted `April 9, 1929i, adintsof more compact construction'than forms hitherto proposed.

Another and important object is to provide a forni of packing which is simple and coinpact and also inexpensive to manufture,

Labyrinth gland packings usually kconiprise a number of annular strips; so arranged as. to yprovide Ladevious path for the steam or` othervfluid. which `tends 4to pass froin the high pressure to the low pressure side of the glandv and for the purpose' of'consideringthe construction and arrangement of thepacking strips it is convenient to refer t0 the cross-sectional forni which they presenten a plane containing the axis of' rotation. yThe,

strips considered'r in this manner are more or less -of 'cantileverforim one end'. being free," 'and the other end, conveniently termed the. root lbeing secured directly or indirectly to the appurtenant f1 gland 4. ineinbenj lt is in this sense thatfthe term endlis hereinafter employed .or the cross-seotion considered Where stated. o Y.

The labyrinth gland packing in accordance with the present invention comprises coaxialV setsiof annular strips securedat one end andv ofsubstantially cylindrical form over ,at

least a portion; of their-axial length adjacent their free ends,fsaid cylindrical portions of anyone-sety being .interleaved With those ot anadjacent set so that the strips of said oneY vsetterminatenear they fixed ends of the adj acent set of stripsp the free end" of each strip lying closej .totlieaopposed outer ksurface of the adjacentistrip on the inside but-beingV Y spaced further :from the inner surface ofthe adjacent strip on ,the outside;YV f f Since in 2therlabryrinthpacking constructed;

asl set forth, above, the constrictions yare,

formed between the inner surfaces near theY Yfree ends of the strips and the outer surfaces n close to the fixed ends" thereof, upon they occurrence of vrubbing contact between. -the strips, the circumferential .dimensions ofthe `reel ends of the strips Will -immediately increase due to local heatingWhile ythe fixed ends of the strips `Will remain substantially niiafected,ipartly because of their thickness and the short efective length of cantilever,

and partly because vthe heat is rapidly Con-V ducted awayu through the adjacent `massesof nietal. Also, since the. interleaved portions of the annular strips doA notsubstantially depart fronithe cylindrical .form they may be packed very closely-together; An eXtraorfdinary` large number of constrictions may thus be provided in ra given cross section of the packing andin view ofthe sensitivity of they self-adjusting action set up upon the occurrence of rubbing Contact, the Vclearances at .the constrictions may be Amade extremely small Without fear of excessive Wear upon the partsl under normal conditions, of service.

The outer circumferential*surface of each` strip may be stepped bj1-increasing the external diameterof the strip adjacent its fixed end, such steppedV portion serving yto provide a constriction in conjunction with the .inside of an adjacent strip, and if desired more than f one such enlargement may be provided upon f f While leaving it relativelythin at its free end:`

- The extremities of the strips land/or the portions Vrat the roots ofthe strips may be shaped, for example, by vcha-nifearing the lend surface of the strin or vconitallvshapiner saidy t Y.

i .l n

root portion, lthe inclined surface thereby-A presented being utilizer vto provide c-snstrioy tio iis,-the passage area ofvtvhichy may be ade lick justed, if desired, by axial displacement of the strips or sets of strips.

A gland according to the invention may comprise some sets of strips b v which adjusting of the constriction is possible, while other sets of strips permit of axial displacement without varying the Width of the constrictions.

Constructions Aof packing according to the invention are illustrated on the accompanyin sheet of drawings in which:

Figs. 1, 2 and 3 are enlarged detail sectional views indicating three possible forms which the packing strips may take;

Fig. 4 shows sets of strips of the form shown by Figs. 1 and 2 assembled together; and

Fig. 5 illustrates one method of mounting a series of packing members according to the invention between a shaft and the casing portion through which it passes. n

All the figuresy represent cross sections taken on a plane containing the axis of rotation, which axis is parallel to the top and bottom edges of the sheet and below the ligures. f f

As shown in Fig. 1 annular strips 1a, which present a cantilever form in cross section appertaining to one of the relatively rotatable members 27, are interleaved with similar strips 1b, appertaining to the other member 28. The strips are truly cylindrical and so arranged that the free ends 2a, 2b, of the respective strips terminate near the. fixed ends of the strips with which they are interleaved and lie close to the opposed outer surface 3a, 3b of the internally adjacent strip so as to provide constrictions 4 therebetween.

A considerable space 5, however, exists between the free end of each strip and the inner surface of the externally adjacent strip, and it will be readily appreciated that should rubbing Contact occur at a constriction 4, the frictional heating of the free end of the strip at such constriction will immediately cause the end of said strip to expand so as to lessen the contact pressure or eventually to reopen said constricted passage. There is no substantial expansion of the inner cooperating strip at the surface 3a or 3b, first, because the greater amount of adjacent metal conducts the heat away more rapidly, and second, because the member 27 or 28, which is not appreciably heated, holds the attached end of the strip against expansion.

It will be observed that in the construction shown the desired effect is obtained merely by increasing the external diameters of the strips adjacent the fixed ends so as to provide stepped portions 6 where the constrictions 4 are formed. The strips are thus strengthened near the roots, where the maximum strength is required, and moreover the radial pitch or distance between the constrictions 4 may be reduced to the minimum thickness of metal which may be safely permitted at the root, in spite of the fact that a free space 5 must be left externally of the free end of each strip.

In the construction above described and shown in Fig. 1, a certain amount of relative axial movement between strips 1a and 1b will cause no alteration of the width of the constrictions 4. In constructions such as shown in Figs. 2 or 3, however, constrictions rare formed between surfaces, some of which are conical, and in these cases the width of such constrictions can be adjusted in a relatively simple manner. n

Fig. 2 shows strips having chamfered extremities 8 associated With the edges 9 of enlargements 9 at the roots of the adjacent strips on the inside so as to provide constrictions 10, the width of which may bealtered by relative axial movement of the members to which the strips are secured. In addi-4 tion to the constrictions 10, further constrictions 11 are provided between the inner surface ofthe free end portion of each strip and the outer surface of the adjacent stri *on the inside in a similar manner to that s own in Fin'. 1.

Fig. 3 shows a construction in which adjustable clearances 12 are afforded between the extremities ofthe strips and conical portions 13 formed at the roots ofl the respectively adjacent strips on the inside. Further constrictions 14 are provided between the outer surfaceof a portion of each strip near the root thereof, rhavinga greater external diameter than the free end of the strip, and the inner surface of the adjacent strip on the outside, the internal diameter of which is reduced at a point somewhat removed from the free end.

Fig. 4 shows sets of packing strips having respectively the forms shown in Figs. 1 and 2 assembled in operative relation. The packing strips extend laterally from annular members 15, 16 and 17 with which they are integral, the central member 16 having on one side a set of strips like those shown in Fig. 1 and associated with similar strips carried bymember 15, and on the other side a set of strips like those shown in Fig 2 and associated with similar strips carried by member 17. Thus, relative axial movement between annular members 15 and 16 may take place without alteration of the width of the constrictions or clearances therebetween, whereas certain of the constrictions between the strips of members 16 and 17 Acan be adjusted by'relative axial movement of said members.

It will be observedthat the strips all present a parallel-sided stepped cross `sectional form with the exception of the outer strips of members 15 and 17, which are plain.

Fig. 5 shows a convenient method of mounting packing members to form a gland between the shaft 18 and casing portion V19 In connection with Fig. 5 it should bek noted thatno claim is 'made tothe herein above describedmethod of assembly" per se.

It will be readily appreciated from the foregoing description that the invention provides a labyrinth` gland packing whereby a large number of restrictions are provided in' a packing of very small dimensions, sufficient clearance being provided externallyof the free end of Aeach strip to permit of ready xpansion thereof upon heating, while one or more constrictions are afforded in conjunction with the inner-periphery of yeach said free ends. At the same time the fixed ends of the strips. are stidenedwto the necessary dei gree so that the expansion upon local heating is limited, and theheat thereof quickly dissipated through the adjacent metal mass,

twill be apparent fromthe drawings that the packing strips are of simple form and without sharp edges or undercut recesses. They may, therefore, be quickly and easily Vmachined, thereby reducing the cost of manufacture.y

While I have shown my invention in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modications withoutdeparting from the spirit thereof, and I desire, therefore, that only such limitations shallbe placed thereupon asVr are imposed by the prior art or as are set forth in the appended claims.v

What I 'claim is z-` L l. Labyrinth'gl-aiid packing for two relatively=rotatable members comprising a plurality vof concentric substantially cylindrical packingstrips Vcarried by one member and a pluralityfof similar strips lcarri-ed by Vthe other member Nand interleaving with the first-mentioned strips, said strips being sulficiently thin and axially elongated to provide radial flexibility of the free ends, each'of said kstr ictions, each rotating member carrying u y Y members.

claim'l comprising least two pairs of interleaved sets of strips, in onerpair of which the cooperating strips have cylindrical surfaces forming theconstrictions, sothat relative axial movement of the strips may take place. withoutalteration of the width of the constrictions thereof, whilst in the otherpair, the strips of one set have conical surfaces and the strips fof the otherset have .edges cooperating w'ith the conical ,surfaces to form at least .some ofthe constrictions, so that relativelaxialmovement of the strips serves to alter the width ofthe last-mentioned conthe strips of one pair extending in one axial direction and the strips of the vother pair extending in the opposite axial direction.

3. Labyrinth gland packing for two relatively rotatable members comprising a plurality of concentric substantially cylindrical packing strips fixed at one end to one memt ber and a plurality of similar strips carried by the other member and interleaving with the first-mentioned strips, said strips being sufficiently thin and axially elongated to provide radial flexibility of the free ends, vthe marginal free end portion of one strip being form-ed lof reduced thickness by increasing the diameter of the inner side thereof, and the adjacent inner strip being provided with; an enlarged portion on the outer side thereof cooperating ywiththe inner 'diameter of said one strip adj acent the portion of reduced Vthickness to provide a packing clearance and being further provided witha, second enlarged portion cooperating c with the inner side of the fr-ee end to provide a second packing clearance, there being sufficient clearance between the free end of eachstrip and the fixed end of the externally adjacent strip to avoid contact upon expansion ofthe free end, i

one of -the surfaces providing the second packing clearance being substantially conical,k

whereby said'second packing clearance may be varied byrelative axial movement of said Intestimony whereof, I have hereunto subscribed my name this v20th day of March,-

KARL inimuinvn.V

strips, other than Vthe outermost, being ex- I ltended radially outwardly at its fixed end to cooperate with theintegral free end of thev adjacent outer strip to providey a fluid seal constriction, there being sufficient clearance between the free end of each strip and the fixed end of the externally adjacent strip to avoid contact upon vexpansion of the free end.

2. Labyrinth gland packing according tok

Images