US 3087434 A
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April 30, 1963 F. 'w. REICHENBACHER TURBOPUMP 2 Sheets-Sheet 1 Filed May 2. 1961 INVENTOR NK REICHENBACHEP ZZMOM ATTORNEY N\ \N \M NY NY NY April 30, 1963 'F. w. REICHENBACHER 3,087,434
TURBOPUMP Filed May 2, 1961 2 Sheets-Sheet 2 //vv/v ToA FRANK n4 RE/CHENBACHER AT TOPNEY United Fatent fire 3,987,434 TURBOPUMP Frank W. Reichenhacher, Windsor, (Donn, assignor to United Aircraft Corporation, East Hartford, Conn, a corporation of Deiaware Filed May 2, 1961, Ser. No. 107,185 6 Claims. (Cl. 103-87) The present invention relates to a turbopump and particularly to a compact assembly of a pump and turbine combination.-
One feature of this invention is an arrangement for the location of the pump with respect to the turbine such that there will be no leakage from the pump that might interfere with the bearings for the pump and turbine shaft. Another feature is an arrangement for lubricating the shaft bearings by the same fluid that powers the turbine. Another feature is the arrangement of a thrust bearing by which to maintain the pump rotor in proper position within the housing. One feature of this invention is a turbopump adapted for pumping liquid metals and adapted to be driven by metallic vapor.
Other features and advantages will be apparent from the specification and claims, and from the accompanying drawings which illustrate an embodiment of the invention.
FIG. 1 is a longitudinal sectional view through the turbopump taken substantially along the line 11 of FIG. 2.
FIG. 2 is a transverse sectional view substantially along the line 22 of FIG. 1.
FIG. 3 is a transverse sectional view along the line 33 of FIG. 1.
FIG. 4 is a fragmentary sectional view substantially along the line 4--4 of KG. 2.
In the arrangement shown a two-stage turbine is utilized to drive a centrifugal pump, the latter being used in the arrangement shown, preferably for pumping a liquid metal, for example, mercury. The turbine is driven by vapor from whatever fluid is available and, in the arrangement shown, the turbine is driven by mercury vapor under pressure.
The device includes a casing 2 which forms the housing for the first-stage turbine rotor 4 which is mounted on a shaft 6. A second casing 8 attached as by bolts 10 to the end of easing 2 has the exhaust cavity 12 for the second turbine stage and also constitutes a casing surrounding the rotor 14 for the second-stage turbine. The casing 8 has a bearing ring 16 for the shaft 6 on the downstream side of the second-stage rotor 14-. Piloted within the casing 2 is an inner support 18 which provides a bearing ring 21 for the shaft 6 between the first and second-stage rotors.
The pump is a centrifugal vaneless pum including a conical rotor element 22 mounted on the end of the shaft 6 and having its conical surface positioned in closely spaced relation to a cooperating stationary conical surface 24 on the inner side of an end cap 26, the latter being mounted on the end of easing 2. as by bolts 28. The cap 26 has a central inlet 30 for the pump. The pump discharges into a cavity 32 formed between the end cap and the casing 2 and the casing may have a discharge passage 34 for the pump. A suitable seal element 36 which will not be affected by the material being pumped is located between the end cap and the casing to prevent leak-age at this point. The pump rotor may be held in position on the end of the shaft as by a locking nut 38 which engages a ring 40 positioned within the end of the shaft. Suitable sealing material 42 in the ring 40' prevents leakage of the fluid being pumped past the projecting stud 44 on the pump element.
The casing 2 has a vapor inlet 46, FIG. 3, by which vapor under pressure reaches a part annular recess 43 formed in the casing. This recess is closed by a ring 50 which has a plurality of nozzle passages 52 therein.
These passages provide for the discharge of vapor under pressure from the cavity 48 against the blades on the firststage turbine rotor. An axially extending pin 54 prevents the ring 56 from turning and the ring is clamped in place by a sleeve 56 forming a liner for a part of the casing 2 and defining the outer wall of the discharge passage 58 for the first-stage rotor. The sleeve 56 is held in position by the support 18.
The support :18 has nozzles 60 therein, FIG. 4, for the discharge of vapor against the blades on the second-stage rotor 14 and the exhaust cavity 12 receives the vapor from the second-stage turbine from which it may be discharged through a passage 62.
The bearings are lubricated by the vapor used for powering the turbine and this vapor is drawn from the passage 58 between the first and second-stage turbine. To accomplish this the support 18 has a lubricant passage 64 therein communicating with an annular groove 66 surrounding the bearing ring 29 and communicating with the inner surface of the bearing element through radial passages 68.
Similarly, the casing 8 has a passage 70 therein communicating with the space 58 through a passage 72 in the support 18 and terminating in a groove 74 surrounding bearing ring 16 and similar to the groove 66. The groove 74 is connected by radial passages 76 with the inner surface of the bearing ring 16. Leakage of the lubricant fluid beyond the end of the bearing surface is prevented by radial passages 78 through the bearing 16 which communicates with an annular groove 80 and thence by a passage 62 to the exhaust cavity 12. The opposite end of the bearing surface provided by the bearing ring 16 communicates with a space 84 which is vented through a passage 86 to a collecting chamber, not shown. A conventional carbon seal 88 prevents axial leakage of vapor from the space 84 and pressure is applied to the seal 88 through a suitable pressure supply 90 positioned in a support bracket 92 to which the turbopump assemblage is attached as by bolts 94. A second carbon seal 96 downstream of the chamber 98 into which pressure is supplied from the supply 96 minimizes leakage of the pressurizing fluid and permits the pressure in the space 98 to be maintained at a pressure slightly higher than that in space 84 so that any leakage occurring Will be into the space 84.
The second-stage rotor 14 is mounted on the shaft 6 and includes an elongated sleeve 160 surrounding the shaft and having axial passages 162 between it and the shaft. These passages connect at the right-hand end through radial grooves 104 with the previously mentioned passages '78 for venting the axial passages 102 into the exhaust cavity 12. The passages 10 2 connect with opposite ends of the bearing provided by the bearing ring 20 through radial passages 166 and 108 thereby controlling the leakage of lubricant beyond the ends of the bearing ring 20. Suitable labyrinth seals 1 10 and 112 on the sleeve 1% at opposite ends of the bearing ring 2tl= provide sealing from space 5% and recess 136 respectively. Similar labyrinth seals 114 also on the sleeve 16-6 control leakage adjacent to the radial passages 78 in the bearing element 16.
The sleeve 1136 for the second-stage rotor is clamped in position on the shaft 6 by a clamping nut 116 which engages With the hub of the first-stage rotor 4 and holds it securely against the end of the sleeve The other end of the sleeve 1% engages a shoulder 118 provided by the shaft. The seal rings 126} and 122 with which the carbon seals 38 and 96 engage are clamped at the end of the shaft remote from the pump by clamping nut 124. Internally of the shaft at the end remote from the pump is positioned a sleeve 126 having internal splines 12% at its outer end for attachment to an accessory that may be driven from the shaft. At the inner end the sleeve and shaft have cooperating splines 13% for driving the sleeve.
The assemblage of pump and turbine rotors on the shaft 6 is heldin desired axial position within the casing by a fluid thrust bearing which operates in conjunction with the second-stage rotor 14. The support 18 and casing 8 have cooperating surfaces 132 and 13% positioned in closely spaced relation to opposite sides of the secondstage rotor 14- to form variable area orifices 133 and 135 on opposite sides of rotor 14. Radially inward of the surfaces 11.32 and 134 both the support 18 and the casing form radially positioned recesses 136 and 138 on opposite sides of the turbine rotor to form chambers 137 and 139 therewith. To these spaces fluid is admitted at the pressure existing in the exhaust space 58. A bleed passage 149 communicates between the passage 64 and the recess 136 and a passage 142 communicates by way of a bleed passage 144- from the passage 70 to the recess 138. Leakage of fluid from the recesses 136 and 138 is limited by the seals 112 and 114 and by the spacing of the surfaces 132 and 134 from the rotor 14. So long as the rotor 14 remains in a mid-position so as to be equally spaced from both surfaces 132 and 134 the same leakage occurs past each of these surfaces and the pressures remain equal in the spaces 136 and 138. If the rotor moves in an axial direction to increase the spacing on one side of the rotor and decrease it on the other, the escape of fluid will be reduced on one side so that pressure will build up in the cooperating chamber thereby tending to restore the rotor to mid-position. The pressure drop resulting from axial displacement of the turbine rotor is dependent upon the restrictions 140 and 144 in the fluid passages to the variable area restrictions 133 and 135.
It is to be understood that the invention is not limited to the specific embodiment herein illustrated and described, but may be used in other ways without departure from its spirit as defined 'by the following claims.
.-1. A pump and turbine combination having an axis and including a housing having closely axially spaced cooperating surfaces and with recesses radially inward thereof, said housing also having a row of turbine nozzles and spaced bearings therewithin, a shaft journalled in said bearings, a turbine on said shaft and having a rotor positioned'between said cooperating surfaces to form a first and second variable area orifice on opposite sides of said rotortherewith and cooperating with said recesses to form a first and second chamber on opposite sides of said rotor therewith and having blades cooperating with saidnozzles, a pressure source, first conduit means including said first chamber and having a first fixed area restriction therein upstream of said first chamber and connecting said pressure source to said first variable area orifice through said first fixed area restriction and said first chamber, and second conduit means including said second chamber and having a second fixed area restriction therein upstream of said second chamber and connecting said pressure source to said second variable area orifice through said second fixed area restriction and said second chamber so i that the pressure in said chambers vary as a function of the areas of said first and second variable area orifices to centrally position said rotor with respect to said closely axially spaced cooperating surfaces, a pump rotor on the end of said shaft, a cap on the end of the housing having on the inner side a substantially conical pump surface cooperating with the pump rotor, said end cap having an axial inlet coaxial with the shaft.
2. An arrangement as in claim 1 in which passages in the housing conduct driving fluid from a point adjacent the nozzles to the bearings.
3. An arrangement as in claim 1 in whichthe housing carries seals at opposite ends of the spaced bearings and the housing has passages from adjacent the seals to the downstream side of the turbine rotor.
4. An arrangement as in claim 1 in which the turbine is a multi-stage turbine and the lubricant for the bearings is taken from the fluid duct between two successive turbine stages.
5. A turbopump arrangement having an aXis and including a housing having closely axially spaced cooperating surfaces and with recesses radially inward thereof, said housing also having turbine nozzles therein, spaced bearings in said housing, a shaft journalled in said bearings, at least one turbine rotor mounted on said shaft'between said bearings and having a rotor positioned between said cooperating surfaces to form a first'and second variable area orifice on opposite sides of said rotor therewith and cooperating with said recesses to form a first and second chamber on opposite sides of said rotor therewith, a pressure source, first conduit means including said first chamber and having a first fixed area restriction therein upstream of said first chamber and connecting said pressure source to said first variable area orifice through said first fixed area restriction and said first chamber, and second conduit means including said second chamber and having a second fixed area restriction therein upstream of said second chamber and connecting said pressure source to said second variable area orifice through said second fixed area restriction and said second chamber so that the pressure in said chambers varies as a function of the area of said first and second variable area orifices to centrally position said rotor with respect to said closely axially'spaced cooperating surfaces, means for passing fluid through said turbine nozzles and blades, and means for supplying said fluid to said bearings.
6. An arrangement as in claim 5 in which the shaft has a conical pump element on one end, and a cap is mounted on the housing to cover the pump element.
References Cited in the file of this patent UNITED STATES PATENTS 1,810,083 Norinder June 16, 1931 2,702,093 Sherrill Feb. 15, 1955 2,752,856 Wolff et al. July 3, 1956