US2943874A

US2943874A - Stern tube safety ring assembly

Info

Publication number: US2943874A
Application number: US534986A
Authority: US
Inventors: Walter J Valdi; Emmett T King
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-09-19
Filing date: 1955-09-19
Publication date: 1960-07-05
Anticipated expiration: 1977-07-05

Description

July 5, 1960 w, VALD] EIAL 2,943,874

STERN TUBE SAFETY RING ASSEMBLY Filed Sept. 19, 1955 2 Sheets-Sheet 1 A as 6 I INVENTORS 68 64 2G WALTER J I/A E MME TT 7./(/

f/GLZ 42 32 1s WW4 /446 ATTORNEYS July 5, 1960 W. J. VALD] STERN TUBE SAFETY RING ASSEMBLY Filed Sept. 19, 1955 2 Sheets-Sheet 2 INVENTORS WALTER J WILD! EMMETT 7. KING r r s 2,943,874

. Patented July 5, 1960 operation, e.g. the assembly has but one moving part and requires only one gauge and one valve for. operation; and

' to provide a stern assembly which cannot damage the 2,943,874 propeller shaft, stern tube, or bearing of a ship; and to STERN TUBE SAFETY RING ASSEIVIBLY Walter J. Valdi, 2546 43m m, and Emmett 'r. King, 846 Clayton St., both of San Francisco, Calif.

Filed Sept. 19, 1955, Ser. No. 534,986 2 Claims. 01,. 286--26) This invention relates 'to propeller-driven seagoing vessels, and more particularly to a stern tube safety ring assembly adapted to be disposed within the stuffing box for the propeller shaft and to be pneumatically operated, when the propeller shaft is not in motion and while the ship is afloat, to seal the" stuffing box against the influx of sea water and enable worn and leaking packing rings to be replaced.

Practically every ships engineering officer has been faced at one time or another with theproblemof dealing with excessive leakage of sea water through the ships stern tube gland. Minor leakage which can be handled by the ships pumps presents merely .an inconvenience problem. But leakage to a degree beyond the capacity of the pumps results in the flooding of shaft tunnels or machinery spaces and other casualties unless .steps are promptly taken to stop the influx of water. At the present time, there is only one way of replacing worn and leaking packing rings with complete safety, and this is .by dry docking the ship and then making the packing ring change. However, it quite frequently happens that time, distance and operational requirement factors make immediate dry docking impossible. Moreover, dry docking amounts to a considerable item in operational expense.

When certain types of vessels are in still water, it is possible to shift weights forward, thus causing the vessel's propeller to be lifted out of the Water'to prevent-leakage through the stern gland while packing is being replaced, but this is done at great risk to the stability of the vessel and also at the further risk of subjecting the vessel to damaging stresses and strains. Furthermore, the occasions when all weather and sea conditions are appopriate for the use of this method of packing replacement are so infrequent as to prevent this method from being employed in the course of usual operations.

A further method which has beenemployed to stop the influx of sea water and enable packing replacement while the vessel is at sea involves the sending of a diver over the stern to wrap a rubber boot, or mattress, about the propeller shaft where it enters the hull. The use of this method not only requires diver personnel and sea conditions appropriate for underwater Work by the diver, but the shape of the shaft and the bearing housingmust be such as to enable the rubber boot to satisfactorily accomplish its sealing function.

The stem tube safety ring assembly of the present invention fully solves all of the problems involved in replacing stern tube packing while a ship is afloat, and enables the same degree of safety to be attained as is attained by way of a dry docking operation.

Among the objects and advantages of the invention are the following: to provide a safety ring assembly which is readilyinstallable in the stern tube of any ship andwithout requiring stern tube alterations for installation; to provide a safetyn'ng assembly which is compact to the point of occupying the space'of only a single ring of packing; to provide a stern tube assembly which is substantially foolproof ,andsimple in structure and mode of provide a safety ring assembly which may be used in bulkhead flange stuffing boxes through which the propeller shaft passes to prevent leakage from adjacent flooded compartments.

Other objects and advantages of the invention will be apparent from the following description taken; in conjunction with the drawings formi g part of this specification broken away to show the safety ring assembly of the invention in place therein;

Figure 2 is an enlarged detail view'of the sectional showing of the safety ring assembly of Figure 1;

Figure 3 is a sectional view of the safety ring assembly,

taken at a point other than the air line connection region shown in Figures 1 and 2 and showing the inflatablesafety ring in a non-inflatedcondition;

Figure 4 is a view similar to that of Figure 3, but showing the ring element in an inflated condition;

Figure 5 is a view in side elevation of the safety ring housing portion of the assembly;

Figure 6 is an enlarged detail view in section taken along lines 6-6 of Figure 5;

Figure 7 is an enlarged detail view in section taken along lines 7-7 of Figure 5; V

Figure 8 is a view in section showing a modified form of the safety ring assembly; and

Figure 9 isa view in perspective of a single length split type inflatable safety ring. p I

With initial reference to Figure 1, thestern tube assembly of a ship comprises a stufiing box tube 10 having a rearwardly disposed annular fiange v12 secured to hull '14 in surrounding and sealing relation to a hull opening for propeller shaft .16 and having a forwardly disposed.

flange 18 and an inwardly disposed annular shoulder 20, a follower ring 22 having an annular flange 24, a plurality of packing rings 26 disposed within'the stufling box tube 10 in surrounding relation to shaft 16 and adapted to be conventionally pressed against shoulder 20 to eflfect a water seal along the propeller shaft, and a plurality of bolts 28 extending through

flanges

18 and 24 and adapted to maintain theend of the follower ring 22 in pressing relation with the packing rings 26 by nuts 30. In the course of normal operation of the ship, the packing rings 26 become worn due to the wear imparted thereto by rotation of shaft 16, and thus it becomes necessary,

to continually adjust the follower ring 22 inwardly of stufling box tube 10 to maintain a sealing pressure of the packing rings against the shaft and stufling box tube.

When the follower ring has been adjusted inwardly of the stuffing box tube to the maximum amount possible,

the packing rings are thereafter no longer pressable. Fur-' ther wear. of the packing rings leads to the influx of sea Water along shaft 16, thus requiring that new or additional packing rings he added in order that-a sealing pressure may be maintained. However, any backing oif of the follower ring leads to increased leakage, and thus it is not feasible for new or additional packing rings 'to be installed when the stern tube is located below the surface of the water. 7 v The safety ring assembly of the invention makes it possible, as above stated, for new or additional packing rings to be installed, once the rotation of shaft 16 has been stopped, while the ship is at sea or afloat.

The safety ring assembly 32 of the invention, which is adapted to be disposed between the shoulder 20 of stuff ing box tube 10 and the endmost packing 26, comprises vu edih eto,

earan epreven Wee area are brought m 'rjt e a i e qrq lll aden a afpair of

annular ring members

34 and 36 which, when they are disposed in mating relation, as'shown in' 'Fignres 3, 4 and 7, define therebetween an annular recess msa a vv e era l at 38,.. ais'1 re essha in a rt e septa "w. tes iy and, s9, n a nfl b -r b er ube 2; a 1 'he n Tis e PQ ."44" ada ted t j i i a d; n taia a P sdfin 4, w ic s t rm d' i w h' Q e .aro 3 h tub "4.2; a y be ng: i s ndicat d n F ures- 5 andg ,4 is Qmlet f wo s Qul rIpa tsA nd 10 formed of'two 'se i-circularparts 52' een' th 48 e ees in "the nn pl t arm ,d 'dvei' i 9 E? res rmed infstufli g ber ' ensblfi la he stats nee, while the inside ch thatlit l arsjthe,

' 02 tnba iii l I diameter of'thi'ring assembly w h ft 6 th he same r i ht y eats? q ee an theiiis'idediametenof he stuflingbox tube shgnldf gq lieihatt a s xlaala e stra I v brating V yn a a h pe rosszb n l adapte atmgjrelati and enveloping, relai ,tion with fespe 't, y

V l 54nd islll nte slbst ntial degr eof finanqihemetat ring;

11 1",- Io atiue movement;

pfrthemropeller shaft andt ewat round the haft.

I lmflrt t beA2,toamoyeintromrits.,d I ,sqkp. nsof; Fig r -.1 andjrwherein; it 1s d spgse d;fully 1n rdly vof;;: he.trnetal, ringz assem- 55 3 3 l il li ifi lldfinjh sfullywinwardposition U r, v ann erl; hereto by... T-shapecLfin g i fivili flfiu d a gp e 4, whereinzthettube nt sassa a astthe b it. 16r.and.prevents the.

Qffi L-W g, l llg the;;shait;.whi l e paclgingr 0 mo ed fin fli plafiegle omprises'; 1 a plug 162 formedjn; the inetal 'ring r ssqn lec e l tobQth a pr ssur a fl through a control valy e;;78 amvair 1line;;8.0;: and a -n11 t. 82:lin nt with stemflO; and adapted-to press g was her against the stuifinglbox shell, topree a sage o wat r, hroug etheshe ei zthe stu fin safety ring assembly and the" propeller: shaft.

Insp ct to ga k t 8 6 1 T e ends, the closed endsbeing other he hetube nfl teias villustrat a a e A modified form of the safety ring' assembly isshofwn inr g fl, w erein-parts identicaltwith those previously described are; designated by; the same ref rence, numeralsf 1 and wherein parts corresponding'tdthe m ple/1011 V described .are/ identified by corresponding numerals plus}; 100. I In thisparticular modification; the 'ing' memljer box s hellin which thestem 70 is disposed." 'lhe, line is connected to a source of pressurized air, not shown, such as the ships air system, or even a hand pump. The gauge 76 measures the air pressure within tube 42 when the tube is inflated, and provides, once the tube has been I inflated and valve 78 has been closed, an indication as to whether the properisealing pressure is being main tained within the tube during use. 7

Ana'nnular gasket 8:6 is'provided between the safety ring assembly and thersboulderlfl of thelstufiing box. shell to prevent. any leakage of water therebetwe'en when the tube 42 is inflated'to seal off the space between the With respect to thetube42, the'short tubular extension. 66 thereof constitutes the only interruption of the continuity v of the T-shaped fin 46.1,.111 order to adapt the tube 42 to be placed over a. propeller shaftwhich is alreachg in place, the tube is initial] formed one length thefform of a single length 136, overlies the :ring niemb'er 13.4" which ;is;seeur ed thereto. bybol'ts 156, the arrangement being lrh l f 7 side oftube] 42, is in engagement with'the stuffing bozo shell shoulder} 20. both when, tlieiube. is inflated audition;

inflated. The tube 42,1when inflated, serves. torseal ofi V thespacebetween the. safety ring QSS'embly andlsliaft -16" and.v to also fseal off-the. spacexbetween the safety; ring i assembly and the vstufling box shell. 10. As' aprecautionary'measure, a sealing .gasket 18 2 fitted within a' groove formed in the periphery of. ringmember 1316 may; be employed to, insure that no leakage will occur, between the safety assembly and the stufling'boxshelllwhen the tube, 42 has been inflated and thelworn-packingnis,

being replaced,

From the foregoing description, it will be clearly seen thatthe'simplicity of the safetyring assembly, t'rom;tl: e standpoint of construction, installation, andntodeofbp y, eration, render'it troublerfree-vin maintenance and opreration. While specific, embodiments of the invention have been shown and described, ,it-is to be understood. that all substantial equiyalents thereof are considered to be within the spirit andv scope-of the invention,

While the stern tube-embodiment,of,the invention for use-i hin s pe aps t e [most mrtan i l se? QE h I fiQI ih epms n ly t mpl es ti li. bev appreciated that the inve nti,o,n; isw not limited to such. application and may: bereadily employed in: such shore nste la i n as o l lls n ustrialv plants; and; 891mm,; Le wherever there maybe a; need to; temporarily seal.

off; one area of shaft;surro,

rs n z.- pace fromianother; h s; laim d i r a 1. A safety ring assembly adaptedito; be Q the stufling box shell;,.o fia .conyentionalssternztube of a a ship and; around; the: hips :propellen; shaft and against 1 theinternal; annular shoulder ofi'said shellg:saidcassembly comprising an, annulanair qti-ght texpansiblestube, nular fin formed;;0n-:'the:;outen periphery jrof saidctube; means .-,;toghold. and housetsaiditubeacqmprisingtairing assembly 1 formed of. two; mating; rhigsmdaptedz to:

fixedlyisecuted togethen'andio gfipping1enldsejesaidi 1 i V fi; lal;.fin;and to laterally-and freely' enclosetsaidftube; and conduit means extendingthroughsaid:shell-anclringr assembly andr-intotsaid rtube adaptedri to introduce preset surized fluidinto saiditubezto expand thesame int'mpre'ss a ing ehgagementzwithr the iperiphery of saidishafrito pre vent the influx of sea water along said shaft when the packing rings of said stufling box are being removed and replaced, said tube being initially adapted to be wrapped around the shaft and said mating rings being each formed of a plurality of complemental arcuate sections, with the sections of one ring being staggered with respect to the sections of the other ring, whereby said tube and ring assembly may be positioned around the shaft while said shaft remains in place.

2. A safety ring assembly adapted to be fixedly disposed within the stuffing box shell of a conventional stern tube of a ship immediately adjacent an annular shoulder formed in said shell and in spaced concentric relation to the ships propeller shaft, said assembly comprising an annular air tight expansible tube, an annular fin formed on the outer periphery of said tube, means to hold and house said tube comprising a ring assembly formed of major and minor mating rings adapted to be fixedly secured together to grippingly enclose said annular fin, and conduit means extending through said shell and ring assembly and into said tube adapted to introduce pressurized fluid into said tube to expand the same into pressing engagement with the periphery of said shaft to said minor n'ng being disposed adjacent said fin and the outer periphery of said tube whereby said tube when expanded may also press against said annular shoulder and effect a water seal between said ring assembly and said stufling box shell.

References Cited in the file of this patent UNITED STATES PATENTS 632,442 Byle Sept. 5, 1899 2,038,140 Stone Apr. 21, 1934 2,174,075 Borchardt Sept. 26, 1939 2,257,119 Johannesen Sept. 30, 1948 2,438,153 Dick Mar. 23, 1948 2,648,554 Gilbert Aug. 11, 1953 FOREIGN PATENTS 647,650 Great Britain Oct. 6, 1948 679,919 Great Britain May 18, 1950