US3102490A

US3102490A - Turbo pumping apparatus

Info

Publication number: US3102490A
Application number: US125013A
Authority: US
Inventors: Donald P Shiley
Original assignee: Thompson Ramo Wooldridge Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1961-07-18
Filing date: 1961-07-18
Publication date: 1963-09-03
Anticipated expiration: 1980-09-03

Description

Sept. 3, 1963 D. P. SHILEY TURBO PUMPING APPARATUS Y Filed July 18, 1961 gesl IN V EN TOR.

BY v'ayd/ A TTORNE YS United States Patent() 3,102,490 TURBO PUMPING APPARATUS Donald P. Shiley, El Segundo, Calif., assigner to Thompson Ramo Wooldridge Inc., Cleveland, hio, a corporation of Ohio Filed July 18, 1961, Ser. No. 125,013 4 Claims. (Cl. 10S- 87) This invention relates generally to pumping apparatus and. more speciiically relates Yto a pump including a conical pumping chamber with a voluted toroid at the large end of the pumping chamber arranged in tangential disposition with respect thereto whereby a conical screw vane impeller will effectively pressurize fluid in the pump under conditions of low suction and at high speed without cavitation. i

It is an object of the present invention to provide a pumping apparatus which tolerates a low suction head at higher operating speeds.

Another object of the present invention is to provide a pumping apparatus which has an improved ability to operate under environmental conditions likely to produce increased quantities of vapor.

A further object of the present invention is to provide a pump which will overcome the centrifuging tendencies of most rotating dynamic type pumps and wherein the pump displays improved vapor swallowing ability.

Another object of the present invention is to provide a high speed pump which operates without objectionable cavitation.

Many other features, advantages and additional objects of lthe present invention will become manifest to those versed in the art upon making reference to Ithe detailed description which follows and the accompanying sheet of drawings in which a preferred structural embodiment of a turbopump incorporating the principles of the present invention is shown by way ot illustrative example.

On the drawings:

The single FIGURE of the drawings shows a cross-sectional view of a tur-bopump incorporating the principles ofthe present invention.

As shown on the drawings:

The turbopump ot the present invention is shown generally at and comprises a pumping unit shown generally at 11 and a motor for operating the pumping unit 11 which, in Athis particular embodiment, constitutes a turbine shown generally at 12.

The pumping unit 11 has a ycasing which comprises a plurality of fastened-together sections including an impeller casing 13 and a volute casing or housing 14.

The impeller Casing or housing 13 has conical side walls 16 flanged as at 17 and apertured as at 1S to facilitate mounting to a suitable mounting pad. An inlet 19 is formed in the impeller housing 13 and the side walls 16 diverge outwardly away from the inlet, thereby to form a pumping chamber 2i? having a small end 2l and a large end 22.

The impeller housing 113 is also iianged as at 23 which is, in turn, apertured as at 24 to accommodate a plurality of fasteners 26 for placing the impeller housing 13 in irm assembly with the volute housing 14.

The volute housing is 4formed with a volute 27 which constitutes a voluted toroid and which is particularly characterized by its tangential relation to the outside wall of the pumping chamber 20. ln this regard, it will be noted the volute housing 14 is formed with a wall portion 28 which is Vdisposed tangentially to the outside contines of the volute 2.7, which wall'ZS is disposed in matching registry with the outside wall 2.9 of the pumping chamber 20 as provided in the impeller housing 13.

Disposed within the pumping chamber 20 is a gen- 31,102,490 Patented Sept. 3, 1963 ice 2 erally conical impeller 30 having a hulb 31 formed with a small end 32 and ya large end 33 and conically tapered walls 34 having positioned thereon screw varies shown at 36. The wall 34 thus extends in divergent relation to the small end l32 in the same general direction of divergence `as the pumping chamber 20, however, it will be noted that the angle of the conical wall 34 is different than the angle of the wall 2:9 so that the cross-section of` the annular space provided between the wall 29 and the wall 34 is actually convergent from the inlet end of the pump towards the large end of the pumping chamber as at 22. t

In this connection, it will be noted that the volute housing 14 is formed with a wall 37 spaced inwardly of the wall 28 and disposed to lie in matching register with the wall 34 of the impeller 30. The wall 37 intersects the voluted toroid constituting the volute 27.

A bearing assembly shown generally at 40 includes a housing 41 connected in firm -assembly to the volute housing V14 by a plurality of fasteners 42 and being flanged as at 43 toretain an outer race 44 of a ball bearing unit including a plurality of shiftable members 46 and an inner race 47. The inner race is engaged lagainst a reduced section 48 of `a shaft 49. The shaft 49 has a further reduced section as at 50 to which the hub 31 of the impeller 30 is connected by means of a fastener 5l. A thrust washer 52 is interposed between a wall 53 formed at the bottom of a cavtiy 54 in the impeller 30, which cavity 54 is circumscribed by the side Walls 34 ofthe impeller 30. l

The tangential relationship between the voluted toroid 27 and the pumping chamber `20 -appears to aiord improved operating advantages which overcome the centrifuging tendencies of most rotating dynamic-type pumps so that the pump of the present invention displays extremely good vapor-swallowing ability.

Apparently the iiow pattern established by the tangential relationship and the increase in the pumping chamber size results in a turbulence which occurs inside of the voluted toroid 27, thereby producing an. improved bubble-swallowing action which results in the bubbles being placed back into solution.V

In order to drive the pump of the present invention, a suitable motor means is provided which, in this form of the invention, includes the turbine 12. The turbine 12 includes a plurality -of casing sections and there is provided a iirst casing section and a second casing sec'- tion 61 held together in rm assembly by a clamping mechanism shown generally at 62. The casing section 61 has a turbine inlet l63` flanged as at 64 and apertured as yat 66 to facilitate mounting to a suitable structure.

The casing part 61 is also formed with a volute charnber 67 and a turbine wheel shown generally at 68 is rotatable in the volute chamber 67, the turbine wheel 68 including a hub 69 and a plunality of vane-s 70.

Any suitable driving liuid may be used as a driving medium and the driving iiuid from a source at increased pressure `is supplied through the inlet 63 to drive the impeller 68, whereupon the spent lluid is exhausted through the volute 67 and an out-let shown at 71. t

The easing section 60 is `formed with a notched recess 713 and the volute housing 14 is likewise formed with a notched recess 7'4. lInserted `within the notched recesses 73` and 74 and extending across the casing construction provided by the volute housing 14 land the casing section 60 is a partition member 76. A heat dam 77 comprising a gasket of 'thermal insulating material is also interposed between the partition 76 and the volute housing 14, thereby to retard the transfer of thermal energy between the casing and housing parts. The volute housing `14 and the casing sections 60 are retained in iirm assembly 3 with one another by a plurality of fasteners shown generally at 78.

'Ilhe partition 76 has an enlarged center boss 79 in which is carried lan outer race 80 of a ball bearing assembly including a plurality of shiftable members 81 and an inner race -82 carried on a bearing section 83 of the shaft 49. The shaft 49 is threaded as at `84 and receives a fastening nut `S6 which abuts against the inner race 82 to assist in retaining the assembly. A shaiit seal shown generally at 8-7 is also contained within the boss 79 and effects 'a seal against the peripheral surface 90 of the shaft 49k The casing section 60 is further provided with a radially inwardly extending wall 91 terminating in an axial boss 92 having an enlarged axial opening 93. The boss 92 is recessed as at 94 to receive a retaining n'ng 96. Retained within the boss 92 by the ring 94 and a shoulder 97 is a slipper-type seal shown generally at '98'. The slipper-type seal has an annular recess 99 formed therein which is communicated with an annular recess 100 formed in the boss '92 by a plurality of radially extending apertures 101. A gaseous fluid purge, for example, a helium gas purge, can be etfectedby connecting a passage-forming conduit 102 tothe boss 92 at the recess 100, which conduit 102 is directed to the outside of the pump through the casing section 60, as shown at 103.

It will be noted that the volute housing 14 is cored out to form a recess 104, while `the casing section `60 is likewise cored out to form a recess 106. Thus, the recess 104 and the recess 106 together form a plenum chamber communicating with the

bearing assembly

80, 81, 82 via an opening 1017 formed in the boss 7'9. Moreover, the volute housing 14 is provided with an enlarged through opening 110,18 which extends between the bearing lassemblyy40 and the recess i104 or plenum charnber. The gaseous fluid present in the plenum chamber 104 through leakage is available to lubricate the bearing assemblies. `In this regard the casing section 60 has an opening 109 formed therein whidh receives a venting conduit 110 by means of which a gaseous lubricating iluid may be |vented from the plenum chamber '104, 1016 for insuring a ow of the uid which has had lubricating contact with the bearing assemblies.

A heat darn made of thermally conductive material also be interposed between the easing section 60 and the casing section `61 and a suitable washer constituting such a heat dam is shown at 111. Accordingly, the partition 76 as well as the washer 74 and the washer 111 operate Vas heat dams to retard the transfer of thermal energy between the pump unit 11 and the turbine unit 12 when in operation.

Although minor modications might be suggested by those versed in the art, it should be understood that I wish to embody within the scope ot the patent warranted hereon all such modications as reasonably and properly come within the scope of my contribution to the art.

I claim as my invention:

-1. A pump comprising an impeller casing having conical side walls disposed at an angle with respect to the impeller axis of rotation and converging toward a center inlet at one end of said impeller casing,

a pump shaft in said casing having a hub carrying 4 rotatable screw vanes in said impeller casing, the angle between said screw vanes and the center line of the pump shaft being such that at flows on or about rated flow the separation forces tending to separate fluid and vapor approach zero, whereby bubbles of vapor will tend to maintain a constant spacing from the impeller casing,

a volute casing at the discharge end of said impeller casing,

said volute casing having a toroidal volute formed therein and including an impeller discharge passage formed with an inside wall disposed to lie in matching register with said hub and intersecting said volute,

thereby making the minimum diameter of the volute smaller than the diameter of the impeller hub at the impe'ller discharge,

the outside wall of said impeller casing and an outside wall of said impeller discharge passage being tangent Ito said volute,

whereby vapor is swept out of the volute by a moving stream of liquid.

2. A pump as defined in claim 1, a turbine connected to said impeller casing, a turbine wheel in said turbine having a shaft connected to said hub, casing means forming 'a plenum between said turbine and said pump, means forming a partition extending across said plenum and including bearing means disposed between the inner portions of said partition and said shaft, and means to leak a lubricant fluid into said plenum for lubricating the bearings, said casing means having a boss surrounding said shaft, a slipper-type seal in said boss engaging said shaft, and passage forming means in said casing means and `at said boss for flushing said slippentype seal with a purging iluid. 3. A pump as dei-ined in claim 1, a turbine connected to said impeller casing, a turbine wheel in said turbine having a shaft connected to said hub, casing means between said turbine and said pump,

said casing means having a boss formed therein surround-ing said shaft, a slipper-type seal in said boss engaging said shaft, l and passage-forming means in said casing means and at said -boss for tushing said slipper-type seal With a purging fluid. 4. Av pump as defined in claim- 2, and heat dams made of thermal insulating material inserted in said casing means to retard transfer of thermal energy from the turbine to the pump.

formed therein References Cited in the ile of this patent UNITED STATES PATENTS 2,049,343 Warren July 28, 1936 2,918,207 Moore Dec.` 22, 1959 2,936,714 Balje May 17, 1960 FOREIGN PATENTS 971,935 France Aug. 23, 1950

Claims

1. A PUMP COMPRISING AN IMPELLER CASING HAVING CONICAL SIDE WALLS DISPOSED AT AN ANGLE WITH RESPECT TO THE IMPELLER AXIS OF ROTATION AND CONVERGING TOWARD A CENTER INLET AT ONE END OF SAID IMPELLER CASING, A PUMP SHAFT IN SAID CASING HAVING A HUB CARRYING ROTATABLE SCREW VANES IN SAID IMPELLER CASING, THE ANGLE BETWEEN SAID SCREW VANES AND THE CENTER LINE OF THE PUMP SHAFT BEING SUCH THAT AT FLOWS ON OR ABOUT RATED FLOW THE SEPARATION FORCES TENDING TO SEPARATE FLUID AND VAPOR APPROACH ZERO, WHEREBY BUBBLES OF VAPOR WILL TEND TO MAINTAIN A CONSTANT SPACING FROM THE IMPELLER CASING, A VOLUTE CASING AT THE DISCHARGE END OF SAID IMPELLER CASING,