US2651553A - Liquid pump - Google Patents

Description

Sept. 8, 1953 E. SIMONIS ET AL 2,651,553

LIQUID PUMP Filed Feb. 25, 1950 3 Sheets-Sheet l Invenlors f/ -f ,4, Simag'is Frank Rf/eaffi Attorney Sept. 8, 1953 Filed Feb. 25, 1950 F/GZ.

3 Sheets-Sheet 2 Hi I II" I nvenlor [/warJ ,4. S'I'M A Home y Sept 1g53 E. A. SIMONIS ET AL 2,651,553

LIQUID PUMP Filed Feb. 25, 1950 I 3 Sheets-Sheet 5 I nventor fa warJ/i Simon/s F nk 19. fleaffi Attorney Patented Sept. 8, 1953 LIQUID PUMP Edward Alec Simonis and Frank Robinson Heath, Harrow, England, assignors to D. Napier & Son Limited, London, England, a British company Application February 23, 1950, Serial No. 145,704 In Great Britain March 8, 1949 4 Claims.

chines such as turbo-compressors, but it will be understood that it is not limited to such applications.

A liquid pump according to the present invention consists of a rotatable member having an inwardly facing annular surface, non-rotatable means for applying liquid to this surface, and a non-rotatable scoop spaced from the said liquid applying means for scooping from the annular surface liquid which is carried round thereby.

The means for applying liquid to the annular surface of the rotatable member may include a device for metering the rate at which the liquid is applied. Thus a substantially uniform delivery of oil can be maintained independently of the speed at Which the shaft is rotating.

A liquid pump embodying the present invention should not be confused with oil throwers which are sometimes mounted on rotating shafts and which dip into a pool of oil in order to convey some of it from the pool to a higher level. Such prior arrangements are quite unsuitable for high speed operation, since when running very fast a thrower exerts considerable windage which either converts the oil into a froth accompanied by considerable undesirable heating, or else it causes a depression in the oil surface in the vicinity of the oil thrower so that the thrower runs dry and picks up no oil at all. 7

In the present invention, however, the windage associated with the high speed rotatable member is turned to advantage in that the rtatable member is enclosed in a housing for receiving surplus liquid and the periphery of the housing is provided with an aperture, the arrangement being such that in operation the windage of the outside of the rotatable member will carry round any surplus liquid and will fling it out of the housing, so that the exterior parts of the rotating member run substantially dry even though the housing is partially immersed in liquid. The housing is partly immersed in a sump containing liquid with the said aperture in its periphery lying above the liquid level in the sump, and the means for applying liquid to the inwardly facing annular surface of the rotatable member may consist of a passage through which member.

liquid can flow by gravity from the sump on to the annular surface. The passage may include a metering orifice for metering the rate at which liquid is applied to the annular surface of the rotatable member.

Where the pump is used for supplying oil to a bearing of a high speed shaft on which the rotatable member is mounted a passage may be provided through which oil can flow from the scoop to the bearing, while oil leaving the bearing can flow back into the housing of the rotatable With this arrangement oil will continually flow from the sump through the metering orifice on to the annular surface of the rotating member and will be carried round by it to a point above the level of the oil in the sump, where it will be scooped off by the stationary scoop. It will then run down from this stationary scoop through the said passage to the bearing. The oil draining from the bearing and any other surplus oil in the system will drain into the housing surrounding the rotatable member, whereupon the windage will immediately pick up this oil and hurl it through the aperture or interruption in the housing back into the sump.

Preferably the volume of the sump is relatively large and. the entry to the metering orifice through which oil flows from the sump to the :annular surface of the rotatable member isarranged not far below the surface of the oil in the sump. Thus the oil in the lower part of the sump is relatively undisturbed so that any sludge or other impurities which settle out in the sump will generally not reach the rotatable member and so will not get circulated through the bearing. Even so, sludge or other impurities may from time to time reach the rotatable member and as an additional precaution to prevent such impurities reaching the bearing circumferential grooves may be formed in the annular surface of the rotatable member in which such impurities may collect and where they will be undisturbed by the scoop.

The invention may be carried into practice in various ways, but one particular embodiment of the invention as applied to oil pumps for the shaft bearings of a turbo-supercharger will be described by way of example with reference to the accompanying drawings, in which:

Figure 1 is a sectional elevation through the turbo-supercharger,

Figure 2 is an enlarged fragmentary elevation showing the arrangement of one of the shaft bearings and the associated oil pump and other parts,

Figure 3 is a view of the auxiliary housing of the oil pump, and

Figures 4 and 5 are two views of an annular scoop-carrying member which fits inside the auxiliary housing.

The turbo-supercharger shown in Figure 1 consists of a single stage axial flow turbine wheel [-9 driving a single stage centrifugal compressor ll, both the turbine wheel ill and the compressor H being mounted coaxially on the same shaft 1-2... At its ends the shaft I2 is supported in end castings l3 and 14 of the main housing of the turbosupercharger by means of similar ball journal bearings, of which one is shown at ["5 in Figure 2. The inner race it of each bearingseats dierectly on the shaft l2, while the outer race :21 is carried in a supporting ring 18 whichis resiliently mounted within the main housing. A multiple-groove oil seal [9 is provided around the shaft [2 adjacent to the inner side of the-bearing l5 and at the outer endof this seal is an -oil thrower 2E and then another multiple-groove seal 2|. These seals I 9 and 2! prevent oil from leaking along the shaft to the centrifugal compressor H (or to the turbine wheel it in the case of the bearing at the other end of the shaft [2) and also prevent air and hot gas from'leaking out along the shaft l2.

It will be appreciated that the ball journal bearings must work in somewhat unfavourable conditions, since heat can readily be transmitted by conduction from the turbine wheel ii) along the shaft [2 to the inner races of the bearings, and moreover the shaft rotates at very high speeds.

It has "been found that to ensure satisfactory operation and life of the bearings considerable care must be exercised in their lubrication; for instance it is desirable that suiiicient oil should be fed through each bearing to carry away surplus heat, but on the other hand it is undesirable to feed an excessive quantity of oil to the bearings. Moreover the oil which reaches the bearings should be clean and should not contain sludge or other impurities.

The present invention provides a lubricating system which fulfills these requirements. The

lubricating system for each bearing is similar so that only one will be described in detail with reference to Figure 2, namely that which, in the drawings, is at the left hand end'of the shaft [2.

The'end casting 13 of the main housing, which contains the bearing 15, is belled out beyond the bearing at 22, and this belled out portion is closed by a detachable end wall 23. The lower part of the belledout portion 22 constitutes an oil sump of relatively large volume. A sight glass 25 is provided in the end wall 23 to enable the level of oil in the sump to be determined, and a filler 25 is provided whereby oil can be added to the sump so as to maintain the oil therein at the desired level. The end wall 23 :also has .a drain plug 25 and a breather aperture 21.

Within the belied out portion of the housing and secured thereto is an auxiliary housing 28 (shown in greater detail in Figure-3) of circular transverse cross section. v0n the front of the auxiliary housing is secured a closure plate 29, which defines an annular chamber within the housing the lowerpartof which constitutes what will be termed the auxiliary sump 38. There is an aperture 3! in the flat rear wall of the auxiliary housing at a point a little below the level of the oil in the main sump, and over this aperture is connected a thimble 32 in which is a meter- 4 ing orifice 33. Oil will thus flow from the main sump to the auxiliary sump 30 through the metering orifice 33 so long as the oil level in the main sump is kept above the orifice 3i.

Secured to the end of the shaft l2 of the turbosuperchar ger and disposed-within the auxiliary housing 28*is a disc or wheel '34 which has at its periphery a roughly cylindrical flange 35 concentric with the shaft [2 and extending towards the centre of the turbo-supercharger. The internal annular surface 41 of this flange 35 is provided with one or more relatively shallow circumfer enti'algronvesfifi'. The overall external diameter of the wheel 34' is only a little less than the interna-li-diameter of the auxiliary housing 28 so- EthatTthBIEliS. a relatively small clearance between the wheel and the housing over the whole of its periphery.

At its lowest point the flange 35 passes between the lowestpoin-t' of the auxiliary housing 28 and the thimble 3E. oil emerging from the metering orifice 33 will drop on the inwardly facing annular'surface-of the wheel 3 1. As best seen Figure 3, at a point slightly above the level ofthe-shaft axis there is an aperture 3? in the circumferential wall of the auxiliary housing which is adjacent to the upwardly moving side of the wheel "34. When the turbo-supercharger is running, 011 will be flung from the outer periphcry of the wheel 34 through the aperture 3 and after dissipating its energy against the walls of the belied out portion 2-2 of the end casting will drain back to the main sump.

Thereare alsoapertures 38 in the flat rear wall 43 of the auxiliary housing '28 which communicate with -theinterior-ofthe belled out portion 22 of the end casting 13 at a point well above the oil level therein, for eq-ualising the pressures inside and-outsidetheauxiliary housing 28.

Secured to the fiat rear wall 48 of the auxiliary housing 28-there=is arr-annular member 40 (shown in Figures 4 and 5-) which carries near to its highest point a scoop H, the leading edge 52 of which is in close relationship with the internal annular surface of the wheel 34. There is a passage l3 just below the leading edge 42 of the scoop, which communicates through passages id and 45 in the auxiliary' housing 28 and the end casting [3, respectively, with the inner side of the ball bearing l5. Oil reaching this side of the bearing will then pass through-the bearing in the outward axial direction, and on emerging from the other side will drain back in to the annular housing 23 through the bore 48 in the flat rear wall of this-l'1ousing.

In operation the lubricating system works as follows. -When the turbo-supercharger is not running the oil in the main sump and in the auxiliarysump 30 will be at the same level, and there will be little-if any oil in other parts of the system. As soon as the turbo-supercharger is started and the shaft -l2 begins to rotate, the wheel 34 will rotate also and will carry round with it some of the-oil from the auxiliary sump 30 on its internalarmular surface-and also on its outer periphery. The oil on the outer periphery will be flung olf by centrifugal force and will sooner-or laterpassout through the aperture 3'1 "in the auxiliary housing 28 into themain sump. Centrifugaliforce will, however, increase the frictional forcebetween the oil and the internal annular surface ,of the wheel 34, and at least some of this oil will be carried round to the highest point of the "wheel, where it will be scooped oii by the scoop 4!. Some of this scooped oif oil will pass through the passages 43, 44 and 45, and so will pass through and lubricate the bearing 15, thereafter drainin back into the auxiliary sump 30.

However, as the wheel 34 rotates and carries round with it some of the oil from the auxiliary sump, the level of oil in the auxiliary sump will fall. Oil will therefore begin to flow into the auxiliary sump 30 from the main sump through the metering orifice 33 of the thimble 32. After a few moments running, a balance will be maintained in which an approximately constant amount of oil is being passed through the metering orifice 33 on to the internal annular surface of the wheel 34, being scooped off and passed through the bearing 15, draining back into the auxiliary sump 30, being caught up to the windage of the outer periphery of the wheel, and finally being flung through the aperture 31 back into the main sump.

Sludge and other impurities which may be present in the oil in the auxiliary sump 30 are likely to be caught up by the windage of the outer periphery of the wheel and flung back into the main sump, where they will sink to the bottom. Such impurities will generally not return to the auxiliary sump 30, since the oil which flows from the main sump to the auxiliary sump comes from just below the surface of the oil in the main sump. Should such impurities get on to the internal annular surface of the wheel 34, centrifugal force will drive them in the circumferential grooves 36 out of range of the scoop 4| so that they will not enter the bearing l5.

Oil which happens to leak along the shaft l2 past the seal 2| will be flung off by the thrower 20 between the seals 2| and I9, and will return to the main sump through a passage 41 in the casting 13 provided for this purpose.

The oil pump described will work effectively not only when the turbo-supercharger is in a normal position, but also if it is rocked about its axis through a considerable angle, say up to 15 or even more to either side of the normal position.

What we claim as our invention and desire to secure by Letters Patent is:

1. A high speed rotary machine which includes a substantially horizontal rotatable shaft, a bearing supporting said shaft, a mounting structure for said bearing, and an oil pump for supplying oil to said bearing, said pump comprising a rotatable driven member directly mounted on said shaft, an inwardly facing annular surface on said member, circumferential grooves formed in said annular surface, a housing completely enclosing said rotatable driven member except that said housing is provided in its periphery with an aperture adjacent to the upwardly moving side of said rotatable driven member, a sump, oil

partly filling said sump and in which said housing is partly immersed with said aperture lying above the surface of the oil, a submerged nozzle projecting into said housing through which oil can flow by gravity from the sump on to said annular surface, a metering orifice in said nozzle adapted to meter the rate at which liquid is applied to said annular surface, said bearing mounting structure having a non-rotatable scoop mounted in the upper part of said housing and adapted to scoop from said annular surface oil which is carried round thereby, said bearing mounting structure having a passage through which oil can flow from said scoop to said bearing, and said housing having an opening communicating with said bearing and through which oil can return to the housing.

2. A liquid pump for high speed operation consisting of a rotatable driven member having a substantially horizontal axis, an annular surface on said member facing said horizontal axis, a reservoir containing liquid, a housing for said driven member partly submerged in the liquid in said reservoir, submerged feeding means in said housing through which liquid can flow from said reservoir on to said annular surface to be carried around thereby, and a stationary scoop circumferentially spaced from said feeding means and arranged to scoop liquid from said annular surface, said housing completely enclosing said driven member except for an aperture in said housing disposed above the normal level of the liquid in said reservoir and adjacent to the upwardly moving side of said driven member.

3. A liquid pump as claimed in claim 2 in which there is a metering orifice of said feeding means adapted to meter the rate at which liquid is applied to said annular surface.

4. A liquid pump as claimed in claim 2 in which circumferential grooves are formed in said annular surface.

EDWARD ALEC SIMONIS. FRANK ROBINSON HEATH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 155,747 Overbagh Oct. 6, 1874 158,169 Fryer Dec. 29, 1874 1,523,707 Nagel June 20, 1925 2,221,189 Hodge Nov. 12, 1940 2,241,870 Scribner May 13, 1941 2,285,754 Money June 9, 1942 FOREIGN PATENTS Number Country Date 313,531 Great Britain June 13, 1929 354,825 Germany June 15, 1920 452,393 France Mar. 6, 1913

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