US2574724A - Multistage rotary pump - Google Patents

Description

Nov. 13', 1951 M. H. BAKER MULTISTAGE ROTARY PUMP 2 SHEETS-SHEET 1 Filed July 31, 1948 INVENTOR MILLARD H. BAKER.

,K/dHw Nov. 13, 1951 Filed July 31, 1948 M. H. BAKER r MULTISTAGE ROTARY PUMP 2 SHEETS-SHEET 2 INVENTOR MI LLARD H. BAKER Patented Nov. 13, 1951 MULTISTAGE ROTARY PUMP Millard H. Baker, St. Louis, Mo., assignor to Fairbanks, Morse & 00., Chicago, 111., a corporation of Illinois Application July 31, 1948, Serial No. 41,831

v 1 Claim. (Cl. 10396) dially inwardly of the pumpin channels is minimized.

It is also an object of the invention to provide a pump of multi-stage type having the suction and discharge ports of the first stage arranged substantially diametrally opposed to the suction and discharge ports respectively of the second or subsequent stages, so that the impeller shaft will not operate under a side loading due to unbalanced forces when the pump is operating.

A further object is to be found in the arrangement in a rotary pump, of impeller ring members which are formed and constructed to define the fluid pumping channel for the several stages, and which permit the attainment of a minimum axial spacing of the fluid impellers and impeller shaft bearings so that it becomes unnecessary to incorporate the usual intermediate shaft bearing and fluid seal means between the pumping stages.

Other objects reside in the form, construction, arrangement and assembly of the several pump housing parts and impeller ring members which will satisfy the foregoing and other objects hereof, particular attention being directed to the exemplary embodiment shown in the accompanying drawing, wherein:

Fig. 1 is a, longitudinal sectional elevational view of the pump assembly;

Fig. 2 is a view of the central portion of the pump housing showing its exterior formation in full line and its interior arrangement of fluid ports and passages in broken line;

Fig. 3 is a further View of the center housing with the end portions and the ring members removed to show additional features thereof;

. Fig. 4 is a sectional elevational view of the center housing as seen along the line 4-4 in Fig.3; Fig. 5 is a fragmentary sectional development of the discharge port zone in the cross-over passage from one stage to the next, the passage being formed in the central housing and arranged as shown by Figs. 2 and 4 with this view being taken at line 5-5 in Fig. 4; and,

3 Figs. 6, 7 and 8 are enlarged side elevational views respectively of the cover end, intermediate and body end impeller ring members, each mem- 2 her being shown in correlated positions matching with the sectional view of Fig. 4 so that these rings may be assembled with the ring of Fig. 8 behind and the ring of Fig. 6 in front of the intermediate ring of Fig. 7.

With reference to Fig. 1, the pump assembly includes a central housing structure In having a mounting ba'se H and providing opposite flanges I2 and I3 at each end of the impeller ring receiving cylindrical bore l4. A body structure [5 is flange mounted at the housing flange I2 with a transverse wall It recessed into the bore l4 and formed with a central stufling box IT. The structure [5 also carries an outboard bearing boss l8 axially spaced from the stuffing box II. The cover structure 20 is flange mounted at the housing flange l3 with a transverse Wall 2| recessed into the bore I4 and formed with a central stuffing box 22. The cover 20 carries an outboard bearing boss 23 axially spaced from the stufling box 22. The body and cover structures close opposite ends of the housing bore l4 to provide a chamber I9 therein. I The impeller shaft 24 is mounted at one end in a suitable bearing in cover boss 23 and extends through the stufling box 22, the central housing H], the opposite stuffing box H, to and through a suitable bearing in the body boss I8. The pro- J'ecting end of the shaft 24 carries a suitable drive plate 25 keyed thereto and arranged for connection with a motor (not shown). Shaft 24 carries a pair of axially spaced fluid impellers 26 and 21 which are substantially identical in construction and are formed with fluid impelling buckets or vanes 28 at each side and in the peripheral zone thereof. Impeller 26 rotates be tween a pair of impeller rings 30 'and SI, and impeller 21 rotates between a pair of impeller rings 3| and 32. In the present assembly, ring 3| is common to each impeller and is positioned between the impellers 26 and 21. The three impeller rings 3|], 3| and 32 are axially fixed between the body structure l5 and the cover structure 20.

It will be noted that the impeller rings 30 and 3| form in assembly a complete fluid channel 33 for the bucket zone of impeller 26. Similarly, rings 31 and 32 form a complete fluid channel 34 for the bucket zone of the impeller 21. In each instance, one-half of the fluid channel is formed in one of the impeller rings, it being noted that the intermediate ring 3| is made axially wider than the body and cover rings 32 and 3!] respectively since it provides one-half of each of the fluid channels. In Figs. 2, 3 and 4, the central housing I0 is 3 shown as being formed with a flanged fluid inlet fitting 35 and a similarly flanged fluid outlet fitting 36 angularly and axially off-set (Figs. 2 and 3) relative to the inlet fitting 35. In forming the housing It], the inlet 35 has a divided flow passage defined by the partition 31, and these branch passages are shown in dotted outline at 38 and 39 in Fig. 2. The inlet branches open at the surface of the central housing bore M in ports 4| and 42 (Figs. 2 and 4) and match with suitable ports formed in the impeller rings 30 and 3|, as will later appear. The housing i6 is further provided with a spirally directed cross-over passage 43 formed in an enlarged portion 44 thereof. The cross-over passage 43 has a single inlet port 45 in the surface of the bore M of housing It), and the discharge from this passage 43 is split or divided (Fig. into branches 46 and 41; as by the partition 48. These branches open in the surface of the bore M at ports 56, 5|, respectively. The outlet fitting 36 opens in the surface of the bore M at a single port 52.

. Considering Fig. 4, it will be observed that the fluid inlet or principal suction port 42 is located diametrally opposite the port 5|, and that the principal discharge port 52 is located diametrally opposite the port 45 leading to the cross-over passage 43. In the present embodiment of a twostage pump, the first stage suction port 42 is opposite the second stage suction port 5|, and the first stage discharge port 45 is opposite the second stage discharge port 52. Comparing Figs. 2 and 4, it can be seen that the first stage is provided with branch inlets 4| and 42 and a single discharge 45, and that the second stage is also provided with branch inlets 50 and 5| and a single outlet 52.

Considering the form and assembly of the impeller rings of Figs. 6 and 7, it must be understood that ring 33 of Fig. 6 is normally placed in front of ring 3| of Fig. '7. When so related, the upper surface of ring 30, particularly its axial flange 55 abuts the transverse wall 2| of the cover structure 20 (Fig. 1). This flange 55 is notched or cut-away to form an inlet port 56. The port 56 opens to a channel 5! which extends across the bottom zone of the ring 30 and proceeds to an inclined channel or tunnel zone 58 which passes to the opposite side of the ring and opens into the one-half fluid channel 33 formed by this ring. The channel 33 extends about the ring 30 and passes under the inlet channel 51 at the tangential zone 59 thereof to open at the outlet port 63. Ring 3| of Fig. '7, has an axial flange 6| which abuts the under flanged surface of ring 30 opposite flange on the latter ring. The peripheral surface of ring 3| is ported at 62 to open to an inlet tunnel passage 63 which is the counter part of inlet channel 51 in ring 30. The tunnel passage 63 opens into the one-half fluid channel 33. This channel 33 is inclined upwardly from the overlying wall 64 to zone 65 and thereafter proceeds in the plane of the ring 3| to the tangential discharge zone 66 and the notched port 61 formed in the ring flange 6|.

It can now be seen that with the ring 30 on top of ring 3| and the two rings placed in the housing ID of Fig. 4, the inlet port 42 will i'e'gisten'with notch 56 of ring 33 and the inlet port 4| (the counter port of port 42 as shown in Fig. 2) will register with the port 62 in ring 3|. The fluid flowing into the channel 51 of ring 30 and tunnel passage 63 of ring 3| (Figs. 1, 6 and 7) will converge at zones 58 and 64 respectively to flow into the complete pumping channel 33 at each side of the first stage impeller 26. The impeller will carry the fluid about this channel 33 and discharge it at the cooperating tangential channels 59 and 66 in rings 30 and 3| respectively for transfer at port 45 into the cross-over passage 43 of housing I0. Rings 36 and 3| are each provided with a locating pin 68 and 69 respectively, which pins fit into an axially directed groove 16 formed in the bore M of the central housing l0 (Fig. 4).

The cooperating relation of rings 3| and 32 will now be described in connection with Figs. '7 and 8, frequent reference being directed to Figs. 1, 2 and 4 for assistance to a complete understanding thereof. The fluid discharge from cross-over passage 43 in central housing In is divided at branch passages 46 and 41 and emerges at ports 50 and 5| respectively. Port 5| is adapted to register with port 12 in the peripheral surface of ring 3| and this port 12 opens to a tunnel passage I3 which is opposite but similar to the first mentioned tunnel passage 63. Tunnel passage 13 opens at zone 14 and at the rear side of ring 3| in the one-half fluid channel 34 which is under lying channel 33. Channel 34 is briefly shown at the lower portion of Fig. '7. This channel 34 continues around the ring 3| and opens at the tangential channel zone 15, this channel zone 15 terminating at the notched port '16. The remaining branch passage 46 and port 50 of the crossover passage 43 registers with the notched port I? at the back side of the ring 32 in Fig. 8. It will be understood that ring 3| is placed in front of ring 32 for purposes of this description, and that the locating pin H for ring 32 fits into the groove 10 (Fig. 4). The notched port 11 of ring 32 opens to the channel 18, and this channel opens through a short tunnel zone of angularly or inclined form to the one-half fluid channel 34 in the upper face of the ring. Channel 34 is bounded at its periphery by the flange T9. The inclined tunnel zone before mentioned starts at the broken line 8|] and opens at 8|, in much the same manner as that portion 58 of ring 30 is formed. Channel 34 in ring 32 proceeds about the same to a tangential channel portion 82 and a discharge notched port 83. The channel portion 82 and port 83 match with the counter parts 15 and 16 of ring 3|.

It can now be understood that the fluid passing ports 50 and 5| (Figs. 4 and 5) enters rings 32 and 3| respectively at notched port 1! and the tunnel port 12 (Figs. 7 and 8) for converging flow into the matching fluid channels 34 at each side of the impeller '21. The impeller moves this fluid toward the tangentially directed and matching channels 15 and 82 for eventual discharge at the matching and notched ports l6 and 83. This discharge occurs as a single stream and enters port 52 (Fig. 4) for flow outwardly of the final discharge fitting 36.

The ring 30 is formed with a land surface 85 which is axially spaced from a similar land surface 86 on ring 3|, so that when assembled at opposite sides of the first stage impeller 26' a running fit is provided radially inwardly of the bucket zone 28 of this impeller. In a like manner, a land surface 87! (Fig. 8) on ring 32 is axially spaced from a land surface 88 (Fig. 1) on the ring 3| opposite surface 33 shown in Fig. 7 so that a running fitis provided radially inwardly of the bucket zone 28 of the second stage impellerfl; Each of the impeller rings is completely open in wardly of these land surfaces and between the axially spaced stuffing boxes 11 and 22. During pump operation, this central area inwardly of the impeller ring assembly will become flooded and a certain amount of flow or circulation will occur through this flooded area from the higher pressure zone at the second stage impeller 21 toward the first stage impeller 26 which is at a lower pressure. External leakage is prevented by suitable gaskets at the body and cover flanged joints and by the shaft stuffing boxes. Accordingly, loss of pumping efficiency is very materially lessened by the present arrangement, and the usually complicated shaft sealing means to distinguish the several stages of pumping effort has been eliminated.

A pump of the above described character may be susceptible of certain changes and modifications without departing from the scope of the present invention as defined in and by the annexed claim.

I claim:

In a two-stage pump, a housing formed as a single casting and having a cylindrical bore open at its ends, a fluid inlet passage having ports opening to said bore, a fluid discharge passage having a port opening to said bore in a zone thereof axially offset from the inlet ports and angularly spaced therefrom by approximately a right angle, and a transfer passage having an inlet opening to the bore in a zone thereof diametrically opposite but axially offset from the zone containing said port of the discharge passage, said transfer passage further having outlets opening to the bore in a zone thereof on the side of the bore diametrically opposite the side containing said ports of the inlet passage; removable body and cover members closing the open ends of said housing bore, a shaft rotatably supported by said members and extending axially through said bore, a pair of bucket impellers fixed on said shaft in the bore, a center ring member and opposite side ring members all disposed in said housing bore and retained therein between said body and cover members; said center ring member and one side ring member forming an impeller channel for one of said bucket im- 6 pellers and providing channel inlet port means in communication with said ports of the housing inlet passage, and a channel outlet port in communication with said inlet opening of the transfor passage; said center ring member and the remaining side ring member forming a second impeller channel for the other bucket impeller and providing inlet port means for the second channel, communicating with said outlets of the transfer passage, and an outlet port for the second channel, communicating with said port of the housing discharge passage; the first said channel and its impeller providing the first or low pressure stage of the pump and the said second channel and its impeller providing the second or high pressure stage of the pump; said center and side ring members providing annular lands in a running seal with the impellers radially inwardly of the buckets thereof, and being open radially inwardly of said annular lands thereof to form a leakage chamber about the shaft in said housing bore and extending axially between said body and cover members, the portions of said impellers extending in said leakage chamber being provided with openings transversely therethrough; and said leakage chamber being flooded during pump operation, with the leakage fluid therein subjected to the pressure differential obtaining between the high and low pressure stages of the pump, such as to result in fluid circulation in the leakage chamber in the direction of the low pressure stage of the pump.

MILLARD H. BAKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,893,616 Ferguson Jan. 10, 1933' 2,006,590 Ferguson July 2, 1935 2,034,549 Abramson Mar. 17, 1936 2,056,553 Abramson Oct. 6, 1936 2,258,416 Leopold et a1. Oct. 7, 19451

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