Shaft seal
Technical field
The present invention and the field relating to the exhaust turbine supercharger that fluid machinery utilizes the exhaust of internal-combustion engine to be loaded in particular.
The present invention relates to a kind of shaft seal of such fluid machinery.
Background technique
Use exhaust turbine supercharger according to standard at present to promote power of IC engine, it is with the turbo machine in the outlet pipe of internal-combustion engine and with the compressor before being positioned at internal-combustion engine, this compressor is connected via common axle with turbo machine.Utilize and carry out supercharging by means of exhaust turbine supercharger combustion motor, loading in the cylinder and therefore fuel mixture promote and the significant power ascension obtained thus for motor.Optionally the energy be combined in I. C. engine exhaust can be changed into electric energy or mechanical energy by means of power turbine.Substitute as generator or mechanical load are connected to turbine shaft place by the compressor in exhaust turbine supercharger situation at this.
Exhaust turbine supercharger sample plot is by rotor (comprising axle, compressor impeller and turbine wheel), assemble for the supporting of axle, the casing component (compressor case or turbo machine case) of water conservancy diversion and supporting member case.
Due to the high pressure process in the flow region of turbine pusher side and compressor side, suitable seal concept should be utilized to seal the axle of exhaust turbine supercharger relative to the cavity of supporting member case.In in the cavity of supporting member case, pressure is usually corresponding to barometric pressure.But the gas pressure in the flow channel of compressor side or turbine pusher side depends on the current point of operation of exhaust turbine supercharger and exceed the pressure in the cavity of supporting member case in most of operating point.But also can consider negative pressure in some cases, such as, in operation at part load or in state of rest.
By the shaft seal of the turbine pusher side of the known exhaust turbine supercharger of file DE2025125, it is by the simple collection chamber on the turbine pusher side of radial bearing and assemble with the piston ring of the seal action between axle and supporting member case.The supporting member machine oil of axially discharging from radial bearing is sprayed onto outwards skew and the shaft shoulder rotated is thrown in collection chamber by centrifugal force.And then the supporting member machine oil so thrown away followed gravity and flowed downward in collection chamber and again turn back in the oil circulation of supporting member lubrication.
Leaked in the cavity of supporting member housing by the impeller back space (Radr ü ckraum) of turbo machine from flow channel and use according to standard the piston ring be made up of metal such as grey cast iron in order to reduce gas.In bearing housing, the piston ring be in stress is clamped in the radial slot with the stop shoulder of axis.As the mating member of piston ring, the axle of rotation is provided with radial slot, and wherein piston ring axially blocks and radial this groove of covering in this groove.Due to the pressure reduction between exhaust pressure and the pressure in supporting member casing interior, to backstop is axially pushed piston ring in the direction of existing pressure gradient within groove.By this piston ring break-in (einschleifen) and all relative to exhaust stream sealed bearing case at one of groove internal surface place of piston ring axially mounting.Also two or more piston ring can be used, as such as disclosed in file CH661964A5, US3180568, US4196910 or EP1860299 in order to improve sealing effect.Show in these files, can how by additional use sealing air (Sperrluft) or to the space between two piston rings carry out exitting relative to heat exhaust lift-off seal effect and exhaust gas leakage can be stoped thus completely in supporting member case.
By the shaft seal of the turbine pusher side of the known exhaust turbine supercharger of file DE3737932A1, oil is discharged between supporting portion and two piston rings from radial bearing wherein.In this case improve oil seal to substitute the simple axial shaft shoulder and use additional disc (Schleuderscheibe).Significantly can reduce the amount of the undesirable supporting member oil clashed in ring groove area thus.Similarly according to the oil extraction realized in the shaft seal of file US4268229 and DE3021349 between radial bearing and contiguous piston ring, wherein oil extraction portion is always formed by chamber.Cavity additionally between two piston rings to be connected with the cavity of supporting member case by means of additional connecting passage and to ventilate on atmospheric environmental pressure.Stop the pressure reduction synthesized on left piston ring thus, with the function making piston ring mainly bear sealing oil and non-tight hot gas.Therefore only right piston ring bears the sealing between the flow channel be under pressure condition and supporting member case cavity.By this constructional variant therefore obtain two kinds separate for Medium Oil (being derived from radial bearing) and exhaust (being derived from flow channel) discharge portion, wherein discharge portion is separated by piston ring.The lubricant oil of discharging from radial bearing (unterUmst nden) axially may to be sprayed onto the ring area of gas seal and to flood whole piston ring when least favourable.Usually the gas pressure in the flow channel of compressor or turbo machine is greater than the gas pressure in the supporting member casing interior in turbosupercharger.Therefore positive differential pressure (gas pressure in flow channel is greater than the gas pressure in supporting member case cavity) causes, and the gas leakage of appearance is blown over (durchbl st) piston ring seals and again carried by the supporting member by mistake penetrated in piston area oil and turns back in the collection chamber of supporting member case.
The above-mentioned situation of opposing attempted by the seal arrangement of the lubricated supporting for rotor shaft described in file DE102004055429B3, and sealing device is in the axial direction relative to the supporting member case of the seals lubricant exhaust turbine supercharger of supply.Rotor shaft is arranged with the first Sealing of gap, labyrinth or piston ring form with the second Sealing of the form in narrow gap or labyrinth, it surrounds circlewise around the oil drain passage that the periphery of rotor shaft extends between itself, and this oil drain passage builds by means of case side oil-discharge trough and the axle side oil-discharge trough arranged in axial same position.Be provided with in oil drain passage and utilize end freely to protrude into the sealing bridge part of the annular in annular oil drain passage in the radial direction at rotor shaft, it is the bar acted in the axial direction for penetrating into the oiling agent in oil drain passage and the radial gap covering the second Sealing.
Such risk is there is in some cases in the shaft sealing concept of all descriptions, namely hot gas is leaked from the impeller back space of exhaust steam turbine by piston ring seals, and supporting member combustion of oil in-situ residual in ring area and oil-discharge trough and cause the coking of shaft seal and the loss of associated thus.Coking risk increases along with the delivery temperature risen with by the leakage rate of the lifting of piston ring and the parts cooling of bad luck.Therefore cooling seal part is initiatively important for the security of operation of shaft seal.
File EP2375000 discloses the shaft seal between the supporting member case and axle of mobile handling machinery, it comprises the Sealing of impeller side and the Sealing of supporting member side, wherein between the Sealing and the Sealing of supporting member side of impeller side, arrange oil-discharging cavity, this oil-discharging cavity is limited by the 3rd Sealing between supporting member case and axle.Arrange between Sealing and the Sealing of impeller side that gas leaves chamber the 3rd, wherein this structure is cooled on one's own initiative by least one nozzle opening in the region of oil extraction ditch, can stop the coking of shaft seal thus.3rd Sealing will be derived from the oil of oil-discharging cavity at this and be derived from the gas separaion that gas leaves chamber.The part of the axle side of Sealing is formed by the sleeve (Aufsatz) on axle alternatively.
Summary of the invention
The object of the invention is, a kind of shaft seal of improvement of the axle supported in supporting member case of fluid machinery is provided, exports the coking risk minimization that can make piston ring seals by the heat from the improvement of Sealing part (Dichtungspartie) wherein.
For the shaft seal being bearing in the axle in supporting member case of fluid machinery according to the present invention (between the impeller back space being located at the impeller of cavity in supporting member case and fluid machinery, with the sleeve on axle, be included between supporting member case and sleeve with the Sealing of the impeller side of the form of at least one piston ring and between supporting member case and sleeve with the Sealing of the supporting member side of the form of seal clearance, wherein oil-discharging cavity is set between the Sealing and the Sealing of supporting member side of impeller side, wherein oil-discharging cavity is by limiting with the 3rd Sealing of the form of seal clearance between supporting member case and sleeve, and be furnished with gas between Sealing and the Sealing of impeller side the 3rd and leave chamber, its middle sleeve has such profile, namely this profile and supporting member case form oil-discharging cavity and gas leaves chamber and comprises at least one for holding the groove of at least one piston ring jointly), towards axle, there are two axially spaced-aparts according to sleeve of the present invention, can the supporting zone of transmitting force in radial direction, two supporting zones so construct, namely it makes transmitting force diametrically become possibility, that supporting zone being arranged in impeller side wherein in two supporting zones is axially arranged in the region of at least one piston ring of the Sealing of impeller side.
By replacing long continuous print bearing portion can reduce the surface of contact between axle and bearing sleeve and therefore reduce to be inputted by the heat of impeller by axle the short bearing portions (Sitz) of two of sleeve (shaft sealing lining) respective end place, wherein advantageously can construct with the cavity of air filling between the supporting zone of transmitting force in two axially spaced-aparts of the sleeve on axle, radial direction.
In ring area, arrange that the distortion caused due to centrifugal force can be kept less by the bearing portion of impeller side by direct.
Alternatively, outside oil-discharging cavity, oil extraction ditch to be incorporated on radial in supporting member case and in supporting member case, to be furnished with at least one oil spurts hole, utilize this oil spurts hole can discharge oil duct load oil, wherein oil extraction ditch extend in the axial direction until impeller side Sealing at least one piston ring on.
Heat thus in support region comparatively great share can directly radially export via lubricant oil outside piston ring.
Advantageously oil extraction ditch is configured to tilt towards the Sealing of impeller side towards axis in the axial direction, thus is directed to oil in oil extraction ditch in supporting member side due to gravity and flows towards impeller side in the axial direction.
The piston ring of impeller side Sealing is directly loaded cooling medium (sealing air) alternatively.Hot gas is stoped to penetrate into supported clearance from impeller impeller back space thus.
Sleeve (shaft sealing lining) can be extended the function of torsional vibration damper alternatively, this can realize by the light pressing at the place of bearing portion in supporting member side and in the strong pressing at the place of bearing portion of impeller side.Wherein the pressing at place of fore bearing portion must correspondingly with vibration damping demand design.For this reason additionally or substitute can introduce friction element such as polytetrafluoroethylene band (Teflonband) in bearing portion, the relative movement at axle place can be made full use of thus, for in order to promote decay constant (D mpfungsmass) further when torsional vibration.
Alternatively, such region (namely it is a part for shaft seal constructed according to the invention) of supporting member case can be configured to embedded piece.Embedded piece can owing to be easily replaced or such as in order to cleaning purpose temporarily takes apart from supporting member case when running the wearing and tearing caused.
In addition the material with heat-conducting property high as far as possible can be selected as the material being used for this embedded piece.
Accompanying drawing explanation
Next set forth in detail according to shaft seal of the present invention by means of drawing.Wherein:
Fig. 1 display according to the diagram of the partial sectional of the exhaust turbine supercharger with radial compressor and axial turbine of prior art,
Fig. 2 shows the cross section guided along axle of the shaft seal through the turbine pusher side of the exhaust turbine supercharger according to prior art,
Fig. 3 shows the cross section guided along axle of the shaft seal through the turbine pusher side of the exhaust turbine supercharger with the sleeve on axle according to prior art,
Fig. 4 display is by the cross section guided along axle of the shaft seal of the turbine pusher side of exhaust turbine supercharger according to the present invention.
List of numerals
10 turbo machines
11 turbine wheels
12 suction ports
13 relief openings
The impeller back space of 15 impellers
20 axles
21,22 sealing bridge parts
30 supporting member cases
The embedded piece of 31 supporting member cases
32 sealing plates
33 sealing bridge parts
34 radial bearings
The delivery line of 35 cooling mediums (sealing air)
39 hat shape shielding parts
41,42 piston rings
43,44 radial seal gaps
50 cavitys in supporting member case
51,52 oil extraction ditches
53 oil-discharging cavities
54 oil drain passages
55 gases leave chamber
56 exhaust passages
60 oily passages
61 oil spurts holes
62 supporting member flanges
63 Internal periphery
70 compressors
71 compressor impellers
72 suction ports
81 with the co-rotational sleeve of axle
821,822 bearing support part
83 axial stop
85 cavitys
86 damping elements.
Embodiment
Fig. 1 display is according to the exhaust turbine supercharger of prior art, and it is with radial compressor 70 and axial turbine 10.Illustrate, in order to the rotor with compressor impeller 71, axle 20 and turbine wheel 11 can be seen to the enclosure portion cutting of the exhaust turbine supercharger drawn.Guide from suction port 72 to the air of compressor impeller 71 and illustrate with thick arrow.Relief opening 13 is directed to by suction port 12 via turbine wheel 11 at turbine pusher side thermal exhaust.Axle 20 rotatably supports in supporting member case 30, usually by means of two radial supports and at least one axially mounting.
Fig. 2 display is according to the shaft seal of prior art, and the cavity 50 in supporting member case separates with the impeller back space 15 of turbine wheel 11 by it.Comprise embedded piece 31 (seal cartridge) at this supporting member case in the region of shaft seal, it is embodied as independently component.Embedded piece 31 is configured to annular, and comprise radial outside oil extraction ditch 52 for radially outwards throw away from radial bearing 34 and the injection oil of laterally sending (abgeben).Directly or indirectly to spray oily splash (bespritzen) embedded piece and to cool embedded piece on one's own initiative thus.By oil spurts hole 61, injection oil is directed on component to be cooled.The supply of spraying oil is realized by the oily passage 60 in supporting member housing 30.Oil spurts hole 61 is so implemented and orientation, namely sprays oil and collide Internal periphery 63 in the region of supporting member housing 30, and embedded piece of getting wet in the region of oil extraction ditch 52.By spraying oil and the oil from supporting member 34 and oil extraction ditch 51, cooling embedded piece all sidedly and being arranged in the piston ring of embedded piece, Sealing and discharge side, and preventing coking to a great extent.In order to improve the cooling effect on piston ring and discharge side, preferably manufacture embedded piece 31 by the material with thermal conduction characteristic high as far as possible.Limit oil extraction ditch 52 by the sealing plate 32 of radially (ausziehen) in the axial direction, sealing plate 32 self by the oil cooling in discharge route 51 but on the other hand.In addition, embedded piece comprises the piston ring 41 and 42 of reentrant part for accommodation two tandem arrangement.In addition, embedded piece comprises oil-discharging cavity 53, leaves chamber 55 and sealing bridge part 33 for the independently gas of the Leakage Gas from two piston rings 41 and 42 being radially arranged in inner region, and it is separate that oil-discharging cavity 53 and gas are left chamber 55 by sealing bridge part 33.
Oil extraction ditch 51 between radial bearing 34 and sealing plate 32 forms the first main discharge route of the supporting member oil left from radial bearing.Sealing plate 32 and the radially relative of axle 20 and the first bridge part 21 that is that put form the seal clearance 43 of the first radial direction, due to sealing gap 43, supporting member oil are minimized to the infiltration oil-discharging cavity 53 from oil extraction ditch 51.The arbor wheel exterior feature of the rotation of oil-discharging cavity 53 is provided with (versetzt) drain tank of radially inwardly dislocation, obtains two injections seamed edge (Abspritzkante) in the left side of this groove and right side thus within oil-discharging cavity 53.Due to gravity, the oil be thrown to by spraying seamed edge in the region of the outside of the radial direction by the groove formation in embedded piece 31 of oil-discharging cavity 53 flows downward along the profile of embedded piece 31 within oil-discharging cavity 53.In order to supporting member oil being led back in the oil circulation of supporting member lubrication from oil-discharging cavity 53, oil-discharging cavity 53 has at least one oil drain passage 54 in the region of bottom.
The embedded piece 31 of shaft seal constructed according to the invention leaves chamber 55 and outstanding by the gas being arranged in oil-discharging cavity 53 side, by around sealing bridge part 33 gas left chamber 55 separate with oil-discharging cavity 53.The gas being configured to annular leaves chamber 55 for collecting the gas of the heat flowing through piston ring 41 and 42.Sealing bridge part 33 and the radially relative of axle 20 and the second bridge part 22 that is that put form the seal clearance 44 of the second radial direction.According to the present invention, two media (by the oil from oil-discharging cavity 53 and the gas leaving chamber 55 from gas) is separated by seal clearance 44 clearly.On the other hand, by the independently exhaust passage 56 that at least one is separated within embedded piece 31 and with oil drain passage 54, the gas of catching in gas outlet chamber 55 is transferred in the common volume (Volumen) of the cavity 50 in supporting member housing.By the separation targetedly of two discharge portions, two media should be stoped to mix in the region of oil-discharging cavity 53, and the coking reduced thus in seal assembly (Dichtverbund) is dangerous.In addition, by large oil extraction ditch 51 and the first Sealing 43, the major part of the supporting member oil left from radial bearing 34 is outwards drawn, and keep supporting member oil away from piston ring portion by oil extraction ditch 52.
Fig. 3 display is according to the shaft seal of Fig. 2 (being only provided with the feature with reference character of adding relative to Fig. 2 for the purpose of better observing), and the arbor wheel exterior feature of the rotation of turbo machine is wherein implemented by hood-like sleeve 81 in the region of shaft seal.Sleeve 81 is on this hot charging to the long bearing portion 82 on axle and the seamed edge constructed on axle is used as axial stop 83 for sleeve 81.
Fig. 4 diagram according to the shaft seal of Fig. 3 according to improvement of the present invention.So construct in this supporting member case, sleeve and bearing support part, namely make to maximize via oil cooled heat output and minimize via the heat input of supporting zone to axle.Sleeve advantageously can be manufactured by the material of good heat conductive.
Abutting on axle 20 of two short bearing portions is utilized according to sleeve 81 of the present invention.The cavity 85 being filled with gas extends between the bearing portion 821 and the bearing portion 822 of impeller side of supporting member side, and this cavity 85 is used as the isolation layer between sleeve and axle.Sleeve utilizes axial stop 83 to abut in axle place in the axial direction.In shown form of implementation, ring-shaped sleeve 81 has the groove that four are positioned at outside.Groove and the corresponding groove in the embedded piece 31 of supporting member case of two supporting member sides jointly formed above-described, leave chamber 55 by the known oil-discharging cavity 53 of prior art and gas.The groove of two impeller side of sleeve is for holding two piston rings 41 and 42, and it forms the sealing of the impeller side of shaft seal.Two piston rings abut in embedded piece 31 place of supporting member case.The embedded piece 31 of supporting member case has oil extraction ditch 52, and it makes to be transported to by lubricant oil in radial region outside sleeve becomes possibility.Extend in the axial direction according to oil extraction ditch of the present invention until at least one piston ring 41 and 42, thus the Sealing coming cooling wheel side by means of lubricant oil can be ensured.Oil extraction ditch 52 is towards the inclination of axle, and making to be incorporated into lubricant oil in oil extraction ditch due to gravity can flow along oil extraction ditch towards impeller side.Supporting member case 30 and embedded piece 31 so construct at this, arrange the discharge possibility for lubricant oil in the region being arranged in bottom based on gravity.Oil flow utilizes thin dark arrow to show in the drawings.Advantageously be derived from supporting member region in order to cooling shaft Sealing uses, in concrete example, be derived from the lubricant oil of the delivery line of radial bearing.
In described form of implementation, shaft seal has sealing air supply department.Be directed in the supported clearance in the impeller side of the piston ring seals of impeller side via the sealing air passage in supporting member case 30 by compressor side (or in the mode of carrying from outside) with the air of the compression of little white arrow display at this.Sealing air is used herein on the one hand directly coolant seal part, and stop on the other hand, hot gas may penetrate into seal clearance from the impeller back space 15 of impeller.
Sleeve (shaft sealing lining) can be extended the function of torsional vibration damper alternatively, this can be realized by the strong pressing at the light pressing by the place of bearing portion 821 in supporting member side and the place of bearing portion 822 in impeller side.Pressing wherein at the place of bearing portion of supporting member side must correspondingly with vibration damping demand design.Additionally or alternatively can introduce the friction element 86 such as polytetrafluoroethylene band of vibration damping in bearing portion for this reason.The relative movement at axle place can be made full use of thus, with in order to promote decay constant further when torsional vibration.
Alternatively can when supporting member case being configured in shaft seal region constructed according to the invention without when independently embedded piece.Corresponding groove, sealing plate and sealing bridge part are introduced directly in supporting member case in this case.The form of implementation with independent embedded piece 31 described in detail relative to the modification without independent embedded piece 31 of one-piece construction has such advantage, namely in order to coolant seal part part object embedded piece 31 by with thermal conductive resin (such as Ck45) material manufacture and therefore independent of used supporting member case material (such as GGG-40).In addition embedded piece is owing to can easily to replace or such as in order to cleaning purpose can temporarily take apart from supporting member case when running the wearing and tearing caused.
In shown form of implementation, shaft seal comprises two piston rings 41 and 42.Alternatively a piston ring also only can be set or it can arrange other piston ring in this region or at other position of shaft seal.
Shaft seal on the shown and form of implementation display turbine pusher side at exhaust turbine supercharger constructed according to the invention described in detail or power turbine.Shaft seal constructed according to the invention can certainly use in other fluid machinery any.