DE3213392A1 - Sealing system for a leakproof stern-tube seal - Google Patents

Abstract

A stern tube (13) for ships has a rear seal (1) and a front seal (2). The leakproof, environmentally beneficial rear seal (1) contains at least one annular chamber (4) in which a medium for lubricating the sealing elements is located. To increase the service life of the sealing elements and the leakproofness of the seal, the medium is pumped in a closed circulation system from a tank (3) through the annular chamber (4) and back to a separator (60) of the tank (3). The pressure PK in this circulation system is lower than the pressure PL in the stern tube and likewise lower than the minimum external water pressure PA min. Both sea water, penetrating from outside for instance, as well as lubricant penetrating from the stern tube (13) penetrating into an annular chamber (4) are carried away with the medium in the circulation system and are separated from the medium in the separator (60). An annular chamber (54) of the front seal (2) can be included in the circulation system. The seals and the lubricating medium can be monitored by means of the circulation system by means of monitoring devices at the tank. In the event of a fault in the circulation system, it is ensured that sufficient medium remains in the annular chambers (4, 54) in order to maintain lubrication of the sealing elements. <IMAGE>

Description

HOWALDTSWERKE - DtIUTSCHE WIiRKT Aktiengesellschaft Hamburg and Kiel

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Sealing system for a leak-proof stern tube seal

The invention relates to an improved sealing system for leak-proof sternrohni seals for ships, through which on the one hand · the leakage of oil from the stern tube and, on the other hand, the penetration of sea water into this bearing is prevented, whereby the lubrication system the security of the seal is improved and the service life of the sealing elements is increased.

So far, no sea or outside water can penetrate the camp mostly used in stern tube bearings oil at a pressure higher than was the greatest occurring pressure of the surrounding water. However, if the rear sealing elements are no longer in perfect working order in such a case, there is a risk of oil from the stern tube or the seal getting into the water. The stern tube bearings closing off Seals usually have several lip seals and oil is used in the chambers between them Lubricate the sealing lips filled.

- .'-- ■ - '. R- ' η, between the water-side sealing

BAD SAI) NAL (DOPY

The invention is based on the object of creating an improved sealing system for leak-proof SteverirchraLdämmungen in which the Sealing element «always adequately lubricated by liquid media at which by the WaIu the pressures of the liquids in neighboring Clear, neither oil nor outside water can pass through an annular chamber of a rear seal and in which the lubrication is improved as a result is that the lubricating medium is continuously circulated, cooled, cleaned and controlled.

This task is in a stern tube seal with a substantially closed circulation system for a sealing element lubricating medium solved in that the pressure of the medium in an annular chamber is lower than the outside water pressure and also lower than the pressure of a lubricant in the stern tube, and that in a separating device the liquid medium is separated from other liquids that penetrate from neighboring rooms, for example, and from dirt, whereby at the same time the circulation system is monitored.

The lower pressure in the annular chamber ensures a rear seal the leakproofness in that in the sealing system penetrating sea water or lubricant from the bearing not on the other Side of the annular chamber, but can only exit from the annular chamber via the separation device. The separation device is expedient a separation tank. The pressure in the circulation system is preferred generated by a higher pressure tank. As far as the space in the ship allows, a single tank can be used be, whose lower part is designed as a separation tank and whose upper part has such a height that the height of the liquid level can determine the intended pressure in the lubrication system.

The medium is at least arranged behind the stern tube hanging chamber expedient «:! se an oil is used. This can be from that Lubricants in the stern tube bearing may be different. Ice cream should however If possible, do not form an emulsion with Wa. '^ t ··· in order to separate the

3b ^ to facilitate sewing of idetank.

BAD OfflÖ ^ 'M-

As the statically lowest point of the circulation system, the ring chamber is preferred arranged so that even with a .Schaden to the circulation system always still lubricating medium remains in the * annular chamber.

A pumping device for generating the circulation of the medium is advantageously provided in the Ringkairsner. A particularly favorable pump device for the present case is known in a manner (DE-OS 22 39 570 = US-PS 3 936 057) by the movement of the medium in the annular chamber as a result of the rotation of the shaft or the liner and at least one the Cross-section of the annular chamber partially obstructing damming element or deflecting element formed. The damming element generates a pressure increase in the medium at one point on the circumference, which is sufficient to direct part of the medium in the direction of rotation upstream of the damming element via a line into the separation tank. During the low flow rate and residence time in the separator tank causes the withdrawal of water and dirt, the baffle element caused in the flowing past it in the annular chamber of the medium to swirl through which also dirt and consumed Fiestandteile the oil from the Dichtkan ⁺ .en the Dichtungsele- ■ ^r .ente washed away and purified, chilled medium to the sealing edge manufacturing

.... · ':'"ÄijgaiOnrt wvrden The use of a storage element, in particular a oolrinen, o .- j also partially type of wave applied, v is in the present case -Xisor.xiov ::; RTEI: .r; aft, because of the back pressure there are also little viscous liquids, such as water that has penetrated into the separation tank

It is possible to provide two circulation systems with different liquid media for a rear stern tube seal. Fine to the Stevenronr

ansohlί ^ ϊοΠνίβ KiiigKairiiner · becomes:;. 3, rinsed with oil. ; iine nearer ¹ le- ^ snca Vorkiuaner wira zn another circulation system of purified ?!] 'Jass-sv duroht'lou -'- jeii. If one of the media enters the chamber of the other M ^ divUu ^ ', it is carried away there by the (ifnlrjufi.yatem i: rd in Jem ? -bs -: -.: \ r-, -

b. / u. enables "ιπί changing care the mediunß and \: νίτψ.Ι vine increased sictierheu, also for <', &> .M-fvenrohrlager, in which the pressure v.es

BATHROOM OFMfMAL

'--32T3'392

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eYes higher hi: in the fting chamber but lower than the outside water pressure ijt.

In a preferred embodiment wtrd in one for the seawater side Rear sealing arrangement provided for a sealing system the front seal of the stern tube included the necessary sealing arrangement. There is also an annular chamber in the front seal formed between two axially spaced sealing elements. The sealing elements are located in this front annular chamber lubricating medium. According to the invention, during normal operation, the liquid medium circulating in the Ural river system is first from the tank headed into the front wall chamber. In this there is preferably a pump device arranged, which causes the circulation. The liquid medium flows from the front annular chamber via a line into the rear one Annular chamber. A further pump device is arranged there, which presses the liquid medium into the separation tank via another line, where foreign components and also dirt, such as consumed oohmienu tt.el and abrasion, are separated from the seals become and there :; Medium abcultlt. Both in

'Λ) the rear as well as in the front seal each one described above .; Barrier element used. Should one of the damming elements fail! The second would still maintain a sufficient circulation of the medium. If necessary, several damming elements with the associated inflow and outflow lines to the annular spaces can also be present in each of the two annular chambers in order to generate a stronger circulation of the medium in the circulation system. The use of the damming elements, which only partially block the cross-section of the annular spaces, is particularly advantageous in the present case, since two of these pump devices work one behind the other in the circulation system and the delivery rates are mutually exclusive

iü can adjust to each other.

The inclusion of the front seal in the circulation system results in better cooling for the front sealing elements, since there is a larger overall ύμγ jointing , and has the effect that the front sealing element ^ is always supplied with purified medium and that the pressure difference between the sealing elements on both sides of the stern tube immediately fat.

BATH ORIGINAL

It i.3t uutx-rdem to · improve the security, provided that the Medium to the Ringkainmiirn and any lines leading to them up to one at such a height that even with an interruption of the Circulation system in each of the annular chambers, no matter how much of the medium remains, that the shaft or the liner seated on it is immersed in the medium and, when rotated, the medium over the circumference of the sealing elements distributed for lubrication. The drain is expediently located from the annular chamber of the rear seal, which contains oil as a medium, to drain away dirt and seawater that is located in the annular space below collects. In this case there is a in the lower half of the annular chamber Damming element with respect to the main direction of rotation of the shaft behind the Arranged drain line from the annular chamber.

Further details of the invention are based on the schematically on the Embodiments illustrated in the drawings are described.

Show it :

FIG. 1 shows a schematic longitudinal section through a stern tube rear and front sealing, and with a circulation system, which a liquid medium through the annular chambers

which leads to the seals and back to a tank, and a lubrication system for the bearing, with the pressures significant for the seal and the bearing being indicated,

FIG. 2 shows a longitudinal section through the front and rear seals according to Figure 1 with indications of the lines provided for the liquid medium of the annular chambers,

FIG. 3 shows a cross section through an annular chamber in the rear seal according to iri-ill in Figure 2,

FIG. 4 shows an enlarged partial longitudinal section through an annular chamber according to IV in Figure 3,

f
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13392

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l-'igur 5 a Wuer- ^ uhrutt. through an annular chamber in the front seal gornäli V - V in Figure 2,

FIG. 6 shows a longitudinal section through a rear seal with two separate circulation systems, each with a separation tank

and a pressure tank for the liquid media, the pressures that are important for sealing are also indicated here.

According to Figure 1, the propeller shaft 11 of a ship is in the stern nut 15 inserted stern tube bearing bushing 14 of the stern tube 13 is supported. A lubricant is fed to the stern tube 13 from a high tank 17 via a line 18. A line 31 can be provided to drain the lubricant from the stern tube 13. The lubricant can also be continuously returned to the elevated tank 17 via a pump in a circuit (not shown).

The rear seal is on the outer side of the stern tube I3

arranged. In this rear seal 1 is a liner 12 arranged on the shaft, and preferably as lip seals Executed sealing elements of the rear seal 1 are in contact of the liner 12, at least one pair of the sealing elements delimiting an annular chamber 4, which is filled with a liquid, the sealing elements lubricating medium is filled. The lip seal 22 separates water and oil in the sealing device according to this example.

On the inner side of the stern tube 13 is the front one Seal 2, which contains another pair of sealing elements, which form an annular chamber 54 and on a bushing 56 on the Shaft 11 is in contact. The front annular chamber 54 is also covered with a liquid, the sealing elements are filled with a lubricating medium. Further details of the seals 1 and 2 are late in connection with FIG. 2 described.

In Figure 1, the Umiaufsyytem for the liquid medium to and from the annular chambers 4 and 54 is shown schematically. The flows from a tank 3, the liquid level of which determines the pressure I " _K in the circulation system

BATH ORIGINAL

Medium through a valve Ί1 exerts τ a line 62 in the front ring chamber 54, is through the l-üng-l · .; Imine r b ^l \ , reaches the rear king chamber ^L \ via line 65 and is pressed from this via the Le'Hing b7 and through a valve fi 'into the lower part 60 of the tank 3. The tank 3 is connected to the atmospheric air via a vent line 30. Vent lines b8 and 69 lead from the highest points of the lines 6b and 67 to the vent line 30. In its lower part 60, the tank 3 contains internals (not shown) for coalescing the oil and separating the water. At the lower part 60, water and dirt can be drained through the valve 35. A drain line 61 is arranged on the upper part 70 of the tank 3, which acts as a pressure tank. If the liquid level is, for example, from the stern tube 13

Oil penetrating into the Ural river system or from penetrating sea water rises in the tank 3, part of the medium can flow off through the line 6i so that the pressure in the circulation system is not an allowable level can exceed.

Various control devices for the circulation system are installed on the tank 3 appropriate. A flow meter 71 in the line 61 gives a warning signal when the tank 3 overflows. A float 72 determines the Height of the liquid level between the lines 61 and 62 should, and also gives a warning signal when the fluid level higher or lower. The distance between lines 6I and should be at least so large that small changes in volume of the medium,

z. B. as a result of warming, not to an overflow of the tank 3 to lead. In the lower part 60, sight glasses 73 are arranged, through which it can be seen whether water has settled in the lower part 60 that is above the valve 35 must be drained. Monitoring the circulating Medium enables an ongoing review of the sealing arrangements, since eg changes in the amount or composition of the medium for defective Point out sealing elements.

The pressure conditions in the seal are indicated in FIG. The outside water pressure P fluctuates between P »max when fully charged of the ship and P. min during ballast travel, which is caused by the water line LWL and ballast water line BWI. is specified. THE PRESSURE PJ. de.- Medium

-: ad original

-lo in the turiiiK.iiNiiiiTii ^; Ι, ^ι ·· Ί .: ■. · [ I in ji .-.! Em KaLl be less than ¹ than P. min. The through the Hue.nt.iiik \ l i-1 -. '. I.Mi ^ Le pressure P. in the .Steven tube 13 should in turn be higher scm ala the pressure P ", which depends on the liquid level in the tank 3. If lip seals are used, the ^l j difference between the pressure P ,, in the ring canisters 4.54 corresponds approximately to the

Stern tube axis and the pressure P _{1 of} the oil in the stern tube of an oil acid

Ie from 2 m to 4 m, preferably from about 3 m (= 26.4 10 Pascal. '. The pressure P "corresponds to a static height h of the medium in the circulation system , but should not be higher than the lowest outdoor water pressure P. min.

Even if · / .. B. a mechanical seal should be used instead of the lip seal d2 .-., The pressure P., in the annular chambers 4.54 must be smaller

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be as P. or · P min.

(iemäli figure. ', .lic rear seal 1 consists of a fastening:; flange ..'<) and the It irii *: i "ο ι J · -ι ι Λ ,. -Jb, 27. The fastening!" lenses i'i) is screwed on in dl «· iuv-re Ιλ.ι \ <.- c \ t- \ .". t ι · ν> · ππι.ιΐί I ¹ ;. You · '!' hurries, - .'0,. "Ν, r. ^J o,. 7 wc. · [· '· Π vliir'i-h iiiri-it. dj ι ν ■. '·. · -l'.; 11- <· 'ot.'Mrviubcn ■ /, usariLT.erii.v ii ι il tn uii.J

/ λ) ί - [>. ΊΜΠκπ Γΐή · ΐ ·· ΐιιι ··· Μ Ι.ι pputui iohtuni; ', ·': !! . ' 1 ,. \ '. , J'i a. Di <- aui / jirr '"- ί i; ■ [· - (; ..! I- · η-

tung li \ : ichl ici.M. a ^ antechamber \> , which is filled with water ϊά \, oe-st-en pressure (.'1.Wa gji-ich that of the uirigeOfc-nd oeewassers can be. The seal 21 largely prevents the ingress of sand, dirt, etc. The seals 22 and 23 enclose the annular chamber 4. In front of the seal 23 there is a space 6, which must already be included in the stern tube 13. The liner 12 has a flange 10 which uird attached to the propeller, not shown.

JD lri the pendant 4 is .vU: h the liquid, the LLppend lines 2d, 2 ~ i

lubricating medium, e.g. B. oil. ; ·]; · Is - as in Figure 3 ge ^ igt i; 3t - through the line U> and ei-κ ··. Channel 39 is fed and flows in scope through the Kingkaimv. ' - In the ring chamber 4 there is a stowage element 24 .v.ir.t; ·> vdn <. '. \ .. Dier.es ti-u ^r · · ..'! rotating shaft 11 a small

lh pressure increase κιΛ <μπι;Uml> -irikuin ' ^: ··; _; "'''itUunLs in channel 66 and the

Line b'f. Μ *>"· Ιλμ works. Da .-> ■ · .'ment 24 as a pump, the« ine circulation. <. ' Medium in df im '- ..:.:>. Star generated. The damming element. 2 «

BATH

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ial beLsUJeL-JWeIse yf-nu /. ·· ιιπΊ preferably consists of a flexible painter. Ks becomes mil. WeMij. ', JU: ri: i eira-m arm on the liner IL! pressed elastically. However, there are distances from the seals 22, 23 in the axial direction, so that part of the medium in the annular chamber 4 can flow past the damming element 2Ί. In this example the flow channel 66 goes down from the King chamber ^J (out to dissipate to collecting case water with the medium. The storage element 24 is therefore t disposed in the lower half of the annular ^chamber!. At the top of the ring chamber 4 there is a radial channel .vb can i.'srden filled with a screw plug 29, through which the Ringkamrner after assembly of the seal. 1 can thus escape the collecting in the upper part of the annular chamber ^l \ air, a L'ntlüftungsleitung be provided.

Since the pressure P ₁ . of the medium in the annular chamber H lower than in the Deft

adjacent spaces of the antechamber 5 and the stern tube 6 is v / iron the lips of the seals 22, 23 away from one another, so that the pressures of the spaces 5 and 6 press the lips against the Lnιfbuchse 12.

The arrows in. | ·. · Π figures: · .ιμ ^ -ν the execution through ia>; Umlaufsy: U- ^ ni bei der · dt-r Vnr'wrirt ;; (Vihil · fiiit.i; f) r>''"^> h <"'nM>"'rc--i' f "'i!' f w> -1 ii- ;. We.-nn l «; i« uoKwiirt.-ifahrL <liu 'Wt; llc erü ./^ egengeset ^ t geurt-ht we ·· !, kfhri. the direction of flow is reversed, nhii ' ¹ i1ali the previous change in transition would be disadvantageous for the I .'ml on sys Lem.

The front seal 2 consists of the fastening flange 50, the ring part 51 and the closing ring 52, between which the lip seals 53 and 55 are clamped, which delimit the front ring chamber 5'I for the medium that lubricates the lip seals. In the area of the front seal 2, the shaft 11 is surrounded by a bushing 56 which is fastened to the flange 5b on a ring placed on the shaft 11. The fastening flange; ch 50 becomes the Stevr-nronres ii on the front cride

appropriate. The space 7 is to the .Stevenrohr 1H 7.u racMrscn and contains .'Lubricant with the original P.. The medium in the ¹ Riiyxairimer ~ ί is under the lower pressure P ,, of the Ufti flow system. The mode v, ^r ir-i as also shown in Figure 3 - via the line b? and the K.-uial i> j is filled in, flows through di · - · '-'ingkammer 5'4, is diverted by a St. ujp learn t 2 ^ a and ClLeIAt dur-ch <i> - \\ K- -inal ßk iuid line 65 further to

. . BAD ORfGfNAL

rear seal 1. Form and function of the storage element 24a .are the same as l'dä ur: the rear seal has been described i SLauelement 24th It is. however, it is expedient to arrange the damming element 24a and the channels 63, 64 in the upper part of the annular chamber b *> - 4 in the front seal 2. After the front seal 2 has been installed, the annular chamber 54 can be filled via a channel 48 and a screw plug 49. The channel 48 can merge into a *. · Ventilation line 47, which z. B. is connected to the vent line 68.

The lines 62,63 and 67 run at such a height with respect to the annular chambers 4, i> 4, that this also with an interruption of the supply cannot become empty of liquid medium. The vent lines 68,69, which are arranged at the highest points of the lines 68,69, ensure that the annular chambers also not z. B. through complete development

l ^c j emptying the tank 3 can be sucked empty. It is therefore possible to renew the medium in the tank 3 even while the shaft 11 is running, without the lubrication of the seal being interrupted.

Figure 6 / WgI. a back tube · «. · Sealing 1 'with two gears

• .Ό UiriLaufiäy.-itt.miTi only for dii-.sc-, m in ten; Seal. The parts are essentially the same as in the rear seal according to FIG. 2 and are denoted by the same reference numerals. In the Ririgkammer 4 'there is a liquid medium, for. B. an oil circulating in a recirculation system through a separation tank 60 '. Another, rear circulation system is provided for the antechamber 5 ¹ , and in this rear circulation system another liquid medium, e.g. B. water, through another separation tank. The pressures P.

jO i.'it. This increases the security against the penetration of. "V ^ was.ser into the stern tube and against the AusUreti.Ti of oil into the sea water, W-with lubrication and cooling of all sealing elements 2l, 2?, 2'i through liquid medii'-n remains guaranteed, and in particular an optimal Siiimierun ^ des Diehtungse] i: rnftriL · ·: 'li'tl is achieved.

AujAerdem: Iind eordnet in the Ririgk.immer · ¹ Ί the damming element ^ 4 'and the channels 39', U ¹ above in ^, so dai. ^J. do Um-r-cut through the annular chamber 4 'dem

ΘΑ0 wi>. · - ·: ■ "- COPY

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in Figure b JargeoU. ·] lten; <ohiiitt through a front annular chamber · similar were. In addition, lit in your Lvu; pu; J according to figure b the tank for 'las medium in the Ririgkammer 4 'divided into a pressure tank 70' and a separation tank 60 ', which are connected by a line 36. The damming element 24 ' pumps the medium in the circuit from the separation tank 60 'through the line 62 ', the annular chamber 4' and the line 67 'back into the tank 6o'. The lines 62 'and 67' run above the annular chamber 4 ', so that vent lines are not necessary for them. The tank 60 'is above the ring chamber 4 'arranged. The annular chamber 4 'is thus the deepest Point of the circulation system in this example. If the Circulating system, the ring chamber 4 'remains filled with the lubricating medium and the sealing elements cannot run dry. A test lead 33 with a test valve 34 can be arranged on top of the separation tank 60 ' to determine whether the returning medium contains water. An overflow line 61 * An is located on the pressure tank 70 ' Further monitoring devices, as described in connection with FIG. 1, can be attached to the tank. Lines b2 'and 67' can be shut off by valves 41 'and 42'. Via a drain valve 35 ', water and dirt can be drained from the separation tank 60' will.

A further separation tank 80 is provided for the rear circulation system, which is filled with clean water twice, and is connected to the antechamber 5 'via the lines 81, 82. The inlet and outlet of the antechamber 5 'is located in the upper half thereof, and a dam 84 is arranged approximately at the uppermost point in the antechamber 5', which causes the water to circulate in the rear circulation system when the shaft rotates. A pressure tank 90, which can also be combined with the separation tank 80, is provided on the rear circulation system. An overflow 8'j on the pressure tank 90 limits the pressure P ^ in the circulation system. Via a drain valve 86, contaminated water can be drained from the separation tank. The lines 8I, 82 also run at such a height to the antechamber 5 'that they cannot be completely emptied.

The pressure P,. ^ In the ^{'annular chamber J} )' is always smaller than the pressure P in the adjacent space ö of the stern tube. The pressure P " _c in the antechamber 5 'of the rear umlaut system is preferably somewhat higher than R, but smaller than P. min.
5

By one or more circulation systems of the type described and here The pressure ratios to be selected produce a seal that is environmentally friendly and leak-proof, and that ensures safety for the stern tube bearing elevated. The constant supply of purified, cooled lubricant to the annular chambers improves the lubrication of the sealing elements and thus their service life. Also enables a circulating system ensures constant monitoring of the seal.

BATH ORIGINAL

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Claims (8)

HOWALDTSWBRKt: - DKUTSCHfc WERKT AKTIEWiBSELLSCHMT H1AMBURu UNL) 'KIEL ■ Sealing system for a leak-proof stern tube seal Patent claims 1. Sealing system for a leak-proof stern tube seal for ships, in which a rear seal (1,1 *) closing off the stern tube comprises at least one annular chamber (4,4 *, 5 ') which is axially opposed by sealing elements (21,22,23) adjacent spaces (5,6) is sealed and the sealing elements (21,22,23) lubricating, liquid medium contains which the annular chamber (4,4 ', 5') with a predetermined pressure in a substantially closed circulation system by means of a Pump device (24,24 ', 84) is fed from a tank, characterized in that the pressure (P ,,) of the medium in the circulation system is lower than the outside water pressure (P.) and lower ah? the pressure Π '. r finer, lubricant is in the stern tube (13) and the tank (60, 60 ', UU) is provided with devices for separating oil, water and dirt and for monitoring the medium. 2. Sealing system according to claim 1, characterized in that in the rear stern tube seal (T) at least two annular chambers (4 ', 5') are parts of separate circulation systems, in each of which a separation device (60 ', & u) for separating the medium of liquids and dirt that have penetrated from neighboring rooms, and which are suitable for absorbing different media with different pressures ^ vht ^ u ^ ". 3. Sealing system according to claim 1 or ', characterized in that an annular chamber (54) of a front seal (2) is included in the circulation system through a rear annular chamber (4) for the medium. 4. Abdichtungüsyatem according to claim 3, characterized in that during normal operation the medium from the tank (3) via a line (62) is first introduced into the front Ririgkammer (54), from her via a line (65) of the rear annular chamber (4) is supplied and flows back from this via a line (67) into the lower part (60) of the tank (3) provided with separation devices. 5. Sealing system according to one of claims 1 to 4, characterized that at least one known baffle element (24,24 ', 24a, 84) is used as a pump device in each annular chamber (4,4', 54,5 ') is, which only partially blocks the cross section of the annular chamber and part of the medium flowing through the annular chamber in a subsequent line (65,67,67 ', 81) pushes. 6. Sealing system according to one of claims 1 to 5, characterized in that that the lines for the medium to and from the annular chambers (4,54, 4 ', 5') are led up to such a height that also at an interruption of the circulation system in each annular chamber so much of the medium remains that the sealing elements (22,23; 53,55) by means of the rotating shaft (11) immersed in the remaining medium can be. 7. Sealing system according to claim 6, characterized in that the lines (65, ö7) are connected at their highest points with ventilation ducts (68, ö9). 8. Sealing system according to one of claims 1 to 7, wherein the sealing elements are lip seals (22,23), the lips of which into the space (b, 6,7) higher pressure, characterized in that the pressure difference between the pressure (I> ) in the annular chamber (4,4 ·, 54) and the oil in the stern tube bearing (13) an oil column of about 2 m to 4 m, preferably of 3 m (= 26.4 χ 10 ^ Pa), where the pressure (P,) in the stern tube bearing (13) smaller than the smallest external water pressure P.. is. λ ΓΠΧΠ BAD ORIGINAL COPY