US2396319A - Pump - Google Patents

Pump Download PDF

Info

Publication number
US2396319A
US2396319A US504608A US50460843A US2396319A US 2396319 A US2396319 A US 2396319A US 504608 A US504608 A US 504608A US 50460843 A US50460843 A US 50460843A US 2396319 A US2396319 A US 2396319A
Authority
US
United States
Prior art keywords
grooves
stator
rotor
ring
pump
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US504608A
Inventor
Beryl A Edwards
Bayard G Duer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ZEPHYR WAYNE Co
ZEPHYR-WAYNE Co
Original Assignee
ZEPHYR WAYNE Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ZEPHYR WAYNE Co filed Critical ZEPHYR WAYNE Co
Priority to US504608A priority Critical patent/US2396319A/en
Application granted granted Critical
Publication of US2396319A publication Critical patent/US2396319A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D5/00Pumps with circumferential or transverse flow

Definitions

  • This invention relates to apparatus such as rotary pumps of the type comprising a rotor and stator having opposed faces, the rotor face being provided with a circular series of blades and the stator face with a raceway or raceways registering with the blades and provided with inlet and outlet ports.
  • a main object of the invention is to provide an efiective seal between the faces whereby the efficiency of the apparatus is enhanced.
  • Another object is to provide a construction facilitating assembly.
  • the invention is shown in a practical embodiment, by way of illustration, in the accompanying drawings, in which:
  • Figure 1 is a side elevation of a motor and pumpunit in accordance with the invention.
  • Figure 2 is a vertical axial section of the pump with a raceway section substantially on line 2--2 of Figure 3.
  • Figure 3 is an end view of the pump, with parts broken away, as seen from the right of Figure l.
  • Figure 4 is a face view of the pump rotor.
  • Figure 5 is a partial face View of the'pump V stator.
  • FIG 6 is an enlargement of a portion appearing in Figure 2 and including a sealing member in accordance with the invention.
  • Figures 7 to 10 are views similar to that of Figure 6, but showing sealing members in different form or arrangement.
  • reference numeral l5 designates a base on which is mounted on electric motor l5 and a pump H constructed in accordance with the invention.
  • the armature shaft I8 01 the motor is in driving connection with the pump shaft I9 through a coupling 20.
  • the pump ll comprises a casing 2
  • the casing carries the shaft l9 in an end bearing 24, Figure 1, and in an inner bearing 25, Figure 2, mounted in a vertical partition, not
  • stator Adja- The stator has plane faces 36 and 31 opposed to the rotor faces 3
  • the outer portion of the stator abuts the outer end of the peripheral wall 28 and is secured in position by screws 40 and 4
  • the stator Inwardly of the face 31 the stator includes an imperforate central web 42 so that the stator closes the'cavity 21.
  • the stator On itsouter side the stator includes a closed wall formation 43 whichterminate in a circula intake neck 44 which is coaxial with the rotor, this Wall formation, including opposite hollow extensions 45 and 46 in communication with inlet ports 41 and 4B.
  • the stator is provided with outlet ports 49 and 50, Figures 3 and 5.
  • designates a cap which is bolted to the end of the casing to close the same.
  • the cap has a top threaded opening 52 in which is engaged an inlet pipe 53, andbelow the opening 52 is a chamber or pas-v sage54 provided with a lateral mouth 55 engaged around the neck 44 and compressing a sealing gasket 56.
  • the mouth 55 Opposite the mouth 55 the cap has a threaded opening 51 for a vacuum gauge V.
  • the fluid delivered by pipe 53 is guided by the chamber 54 to the stator cavity and the inlet ports 41 and 48.
  • An outlet chamber 58 is defined between the cap and the stator and at its upper end is in connection with a passage 59 in the casing 2
  • a groove 63 Formed in the face 3
  • the face 32 of the rotor is provided with a similar groove 68 concentric with the first.
  • the stator faces 36 and 31 are provided with grooves 69 and 10, exactly like the rotor grooves 63 and 68 and registering with the latter, respectively.
  • Disposed in the grooves 63 and 69 is an endless sealing ring H of bronze or other suitable material, this ring having a width equal to the combined width of the cylindrical portions of the two grooves.
  • the angularly related outer walls of the grooves serve to center the ring, and, with the latter, define annular chambers 12 and 13 at the ,sides of the ring.
  • a closed ring H is similarly disposed in the opposite grooves 68 and 10 with chambers at each side thereof.
  • the rings are .fitted in the grooves with close tolerances, and when the pump is in operation the'high pressure acts to decrease the tolerances past the rings is reduced to a minimum by wiredrawing between the faces of the rotor and stator, also between the rings and the groove walls, for example, the ring II and wall 64,- Figure 6.
  • the ring II and wall 64 Upon reaching the triangular spaces as at 12 the vol-,
  • ume of liquid is increased materially, thus reduc-' ingthe velocity and pressure in these spaces.
  • the liquid is again wiredrawn between the sealing rings and the groove walls, for example, the ring 1
  • the rings retain their emciency for a long period of use, but when worn/can be easily replaced .by the ordinary mechanic.
  • FIG. 2 the rotor is shown as provided with openings H and for pressure equalization.
  • the casing has a drainage plug 16 and the cap a drainage plug 11.
  • the grooves havearcuate end walls, as at 80, which serve as before to center the rings so that annular chambers are provided at the sides thereof.
  • apparatus comprising a rotor portion having a series of blades arranged on a circle whose center is on the axis of said rotor portion and having an annular lateral face concentric with said circle, a stator portion having a lateral face opposed to the face of said rotor portion, the improvement which comprises opposed circular grooves 'provided in said faces concentric with said circle, a floating sealing ring extending laterally into both of said grooves, the combined width of said grooves being greater than the width of said ring, and means positioning the ring so that an annular chamber is provided at each side of the ring.
  • apparatus comprising a rotor portion having a lateral series of blades arranged on .a circle whose center is on the axis of said rotor portion and having annular lateral faces inwardly and outwardly of said circle concentric therewith, a stator portion having a raceway opposed to said impellers and having faces inwardly and outwardly of said raceway opposed to the inner and outer rotor portion faces respectively, the immovement which comprises a set of opposed circular grooves provided in the opposed inner faces of the rotor and stator portions concentric with said circle, a set of opposed circular grooves provided in the opposed outer faces of the rotor and stator portions concentric with the first set, float ing sealing rings in said sets of grooves, each of said rings extending laterally into both grooves of the set with which it is associated, the grooves of each set having a combined width greater than the width of the ring therein, and means positioning each ring so that an annular chamber is provided at each side thereof.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Description

Mai-ch 12, 1946. .B. A. EDWARDS ET AL 2,396,319
PUMP
Filed Oct. 1, 1945 3 Sheets-Sheet l ,Bagagd 1%. er, f :flflorne March 12, 194 V B. A. EDWARDS ET AL 7 2,396,319
PUMP
Filed Oct. 1, 1945 5 Sheets-Sheet 5 ii/ w B3 ling 231i G..Due:,
Patented Mar. 12, 1946 PUMP Beryl A. Edwards and Bayard G. Duer, Decatur,
Ill., assgnors to Zephyr-Wayne Company, De-
catur, 111., a partnership Application October 1, 1943, Serial No. 504,608
4 Claims. (Cl. 103-411) This invention relates to apparatus such as rotary pumps of the type comprising a rotor and stator having opposed faces, the rotor face being provided with a circular series of blades and the stator face with a raceway or raceways registering with the blades and provided with inlet and outlet ports. A main object of the invention is to provide an efiective seal between the faces whereby the efficiency of the apparatus is enhanced. Another object is to provide a construction facilitating assembly. The invention is shown in a practical embodiment, by way of illustration, in the accompanying drawings, in which:
Figure 1 is a side elevation of a motor and pumpunit in accordance with the invention.
Figure 2 is a vertical axial section of the pump with a raceway section substantially on line 2--2 of Figure 3.
Figure 3 is an end view of the pump, with parts broken away, as seen from the right of Figure l.
Figure 4 is a face view of the pump rotor.
Figure 5 is a partial face View of the'pump V stator.
Figure 6 is an enlargement of a portion appearing in Figure 2 and including a sealing member in accordance with the invention, and
Figures 7 to 10 are views similar to that of Figure 6, but showing sealing members in different form or arrangement.
Referring to the drawings and first to Figures 1 to 6, reference numeral l5, Figure l, designates a base on which is mounted on electric motor l5 and a pump H constructed in accordance with the invention. The armature shaft I8 01 the motor is in driving connection with the pump shaft I9 through a coupling 20.
The pump ll comprises a casing 2| provided with a bottom flange 22 which is bolted to the base H5. The casing carries the shaft l9 in an end bearing 24, Figure 1, and in an inner bearing 25, Figure 2, mounted in a vertical partition, not
- shown, in an interior cavity 23, Figure 2. Adja- The stator has plane faces 36 and 31 opposed to the rotor faces 3| and 32, and between these stator faces is a pair of arcuate raceways 38 and 39, Figure 3, which register with the rotor groove 33. The outer portion of the stator abuts the outer end of the peripheral wall 28 and is secured in position by screws 40 and 4|, Figure 3. Inwardly of the face 31 the stator includes an imperforate central web 42 so that the stator closes the'cavity 21. On itsouter side the stator includes a closed wall formation 43 whichterminate in a circula intake neck 44 which is coaxial with the rotor, this Wall formation, including opposite hollow extensions 45 and 46 in communication with inlet ports 41 and 4B. Outwardly of the wall formation 43 the stator is provided with outlet ports 49 and 50, Figures 3 and 5.
Reference numeral 5|, Figures 1, 2, and 3, designates a cap which is bolted to the end of the casing to close the same. The cap has a top threaded opening 52 in which is engaged an inlet pipe 53, andbelow the opening 52 is a chamber or pas-v sage54 provided with a lateral mouth 55 engaged around the neck 44 and compressing a sealing gasket 56. Opposite the mouth 55 the cap has a threaded opening 51 for a vacuum gauge V. The fluid delivered by pipe 53 is guided by the chamber 54 to the stator cavity and the inlet ports 41 and 48. An outlet chamber 58 is defined between the cap and the stator and at its upper end is in connection with a passage 59 in the casing 2| which has a threaded outlet opening 60 in connection with a discharge pipe 6|. .A threaded opening 52 communicates with the passage 59 and receives a pressure gauge P.
Formed in the face 3| of the rotor concentrically with the axis is a groove 63 which has con centric cylindrical wal s 64 and 65 and triangularly arranged end walls 66 and 61, Figures 2 and 6. The face 32 of the rotor is provided with a similar groove 68 concentric with the first. The stator faces 36 and 31 are provided with grooves 69 and 10, exactly like the rotor grooves 63 and 68 and registering with the latter, respectively. Disposed in the grooves 63 and 69 is an endless sealing ring H of bronze or other suitable material, this ring having a width equal to the combined width of the cylindrical portions of the two grooves. The angularly related outer walls of the grooves serve to center the ring, and, with the latter, define annular chambers 12 and 13 at the ,sides of the ring. A closed ring H is similarly disposed in the opposite grooves 68 and 10 with chambers at each side thereof.
The rings are .fitted in the grooves with close tolerances, and when the pump is in operation the'high pressure acts to decrease the tolerances past the rings is reduced to a minimum by wiredrawing between the faces of the rotor and stator, also between the rings and the groove walls, for example, the ring II and wall 64,- Figure 6. Upon reaching the triangular spaces as at 12 the vol-,
ume of liquid is increased materially, thus reduc-' ingthe velocity and pressure in these spaces.'
The liquid is again wiredrawn between the sealing rings and the groove walls, for example, the ring 1| and wall 65, Figure 6. Due to these factors, the floating rings provide a nearly perfect seal with a corresponding enhancement of pump efliciency. The rings retain their emciency for a long period of use, but when worn/can be easily replaced .by the ordinary mechanic.
In Figure 2 the rotor is shown as provided with openings H and for pressure equalization. The casing has a drainage plug 16 and the cap a drainage plug 11.
In Figure I the ring II is the same as before,
as are the cylindrical walls I8 and 19 of the grooves. However, instead of having angularly related end walls, as at Hand 61, Figure 6, the grooves havearcuate end walls, as at 80, which serve as before to center the rings so that annular chambers are provided at the sides thereof.
In Figure 8, the groove walls, as at 8! and 82,
are cylindrical throughout and have flat end walls, as at 88. The ring 84 is centered by the heads of screws 85 and 88 threaded in the sides thereof, or similar spacing means, such as pins or lugs, see also Figure 9.
In Figure 10 the grooves have cylindrical wall portions 81 and 88 and outward reduced extenand it will be understood that other variations in the form and arrangementof parts are possible in the practice of the invention and are contemplated under the claims which follow.
9,896,819 at the far sides of the rings. Leakageof liquid We claim:
1. In apparatus comprising a rotor portion having a series of blades arranged on a circle whose center is on the axis of said rotor portion and having an annular lateral face concentric with said circle, a stator portion having a lateral face opposed to the face of said rotor portion, the improvement which comprises opposed circular grooves 'provided in said faces concentric with said circle, a floating sealing ring extending laterally into both of said grooves, the combined width of said grooves being greater than the width of said ring, and means positioning the ring so that an annular chamber is provided at each side of the ring.
2. Structure according to claim 1 wherein the grooves are shaped so as to constitute the positioning means."
3. Structure according to claim 1 wherein the positioning means is constituted by spacers carried by the ring, I
4. In apparatus comprising a rotor portion having a lateral series of blades arranged on .a circle whose center is on the axis of said rotor portion and having annular lateral faces inwardly and outwardly of said circle concentric therewith, a stator portion having a raceway opposed to said impellers and having faces inwardly and outwardly of said raceway opposed to the inner and outer rotor portion faces respectively, the immovement which comprises a set of opposed circular grooves provided in the opposed inner faces of the rotor and stator portions concentric with said circle, a set of opposed circular grooves provided in the opposed outer faces of the rotor and stator portions concentric with the first set, float ing sealing rings in said sets of grooves, each of said rings extending laterally into both grooves of the set with which it is associated, the grooves of each set having a combined width greater than the width of the ring therein, and means positioning each ring so that an annular chamber is provided at each side thereof.
BERYL A. EDWARDS. ,BAYARD a. DUER.
US504608A 1943-10-01 1943-10-01 Pump Expired - Lifetime US2396319A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US504608A US2396319A (en) 1943-10-01 1943-10-01 Pump

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US504608A US2396319A (en) 1943-10-01 1943-10-01 Pump

Publications (1)

Publication Number Publication Date
US2396319A true US2396319A (en) 1946-03-12

Family

ID=24006995

Family Applications (1)

Application Number Title Priority Date Filing Date
US504608A Expired - Lifetime US2396319A (en) 1943-10-01 1943-10-01 Pump

Country Status (1)

Country Link
US (1) US2396319A (en)

Cited By (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2566892A (en) * 1949-09-17 1951-09-04 Gen Electric Turbine type pump for hydraulic governing systems
US2608157A (en) * 1948-09-07 1952-08-26 F E Myers & Bro Co Horizontal jet type pump for shallow or deep wells
US2662479A (en) * 1950-11-03 1953-12-15 Bendix Aviat Corp Turbine pump or motor
US2671404A (en) * 1950-03-15 1954-03-09 Florin W Krueger Turbine pump
US2672098A (en) * 1950-08-28 1954-03-16 Bilsky Samuel Rotary fluid pump
US2740614A (en) * 1950-10-12 1956-04-03 Air Preheater Circumferential sealing leaves
US2793491A (en) * 1950-12-07 1957-05-28 Gen Motors Corp Variable area jet nozzle
US2797939A (en) * 1954-05-18 1957-07-02 City Nat Bank And Trust Compan Self-contained cartridge type rotary seal with floatably mounted sealing members
US3095820A (en) * 1960-02-29 1963-07-02 Mcculloch Corp Reentry rotary fluid pump
US3111904A (en) * 1961-12-18 1963-11-26 Shell Oil Co Turbine pump
US3139232A (en) * 1959-08-24 1964-06-30 Orville N Peterson Refrigeration pump
US3356033A (en) * 1965-10-22 1967-12-05 Ford Motor Co Centrifugal fluid pump
US3360193A (en) * 1965-12-29 1967-12-26 Rotron Mfg Co Regenerative compressors with integral mufflers
US3392675A (en) * 1965-10-22 1968-07-16 Ford Motor Co Centrifugal pump
US3497046A (en) * 1967-09-27 1970-02-24 Horton Mfg Co Inc Rotary seal for clutch and brake members having relative rotation and reciprocation
US3518020A (en) * 1968-04-04 1970-06-30 Gen Electric Split seal ring assembly for compressors
US4489951A (en) * 1983-08-17 1984-12-25 Ebara Corporation Mechanical seal
US4492515A (en) * 1982-05-12 1985-01-08 Nippondenso Co., Ltd. Pump apparatus
US4556363A (en) * 1982-06-21 1985-12-03 Nippondenso Co., Ltd. Pumping apparatus
US5074747A (en) * 1988-07-13 1991-12-24 Osaka Vacuum, Ltd. Vacuum pump
US5217346A (en) * 1988-07-13 1993-06-08 Osaka Vacuum, Ltd. Vacuum pump
US5219269A (en) * 1988-07-13 1993-06-15 Osaka Vacuum, Ltd. Vacuum pump
DE4415566A1 (en) * 1994-05-03 1995-11-09 Sero Pumpenfabrik Gmbh Self=priming multistep rotary pump
US6164656A (en) * 1999-01-29 2000-12-26 General Electric Company Turbine nozzle interface seal and methods
US20050249617A1 (en) * 2004-05-10 2005-11-10 Visteon Global Technologies, Inc. Fuel pump having single sided impeller
US20050249581A1 (en) * 2004-05-10 2005-11-10 Visteon Global Technologies, Inc. Fuel pump having single sided impeller
US20070160465A1 (en) * 2006-01-10 2007-07-12 Roudnev Aleksander S Flexible floating ring seal arrangement for rotodynamic pumps
US20140227086A1 (en) * 2013-02-11 2014-08-14 Fluid Equipment Development Company, Llc Method And Apparatus For Sealing A Rotating Machine Using Floating Seals

Cited By (36)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2608157A (en) * 1948-09-07 1952-08-26 F E Myers & Bro Co Horizontal jet type pump for shallow or deep wells
US2566892A (en) * 1949-09-17 1951-09-04 Gen Electric Turbine type pump for hydraulic governing systems
US2671404A (en) * 1950-03-15 1954-03-09 Florin W Krueger Turbine pump
US2672098A (en) * 1950-08-28 1954-03-16 Bilsky Samuel Rotary fluid pump
US2740614A (en) * 1950-10-12 1956-04-03 Air Preheater Circumferential sealing leaves
US2662479A (en) * 1950-11-03 1953-12-15 Bendix Aviat Corp Turbine pump or motor
US2793491A (en) * 1950-12-07 1957-05-28 Gen Motors Corp Variable area jet nozzle
US2797939A (en) * 1954-05-18 1957-07-02 City Nat Bank And Trust Compan Self-contained cartridge type rotary seal with floatably mounted sealing members
US3139232A (en) * 1959-08-24 1964-06-30 Orville N Peterson Refrigeration pump
US3095820A (en) * 1960-02-29 1963-07-02 Mcculloch Corp Reentry rotary fluid pump
US3111904A (en) * 1961-12-18 1963-11-26 Shell Oil Co Turbine pump
US3356033A (en) * 1965-10-22 1967-12-05 Ford Motor Co Centrifugal fluid pump
US3392675A (en) * 1965-10-22 1968-07-16 Ford Motor Co Centrifugal pump
US3360193A (en) * 1965-12-29 1967-12-26 Rotron Mfg Co Regenerative compressors with integral mufflers
US3497046A (en) * 1967-09-27 1970-02-24 Horton Mfg Co Inc Rotary seal for clutch and brake members having relative rotation and reciprocation
US3518020A (en) * 1968-04-04 1970-06-30 Gen Electric Split seal ring assembly for compressors
US4492515A (en) * 1982-05-12 1985-01-08 Nippondenso Co., Ltd. Pump apparatus
US4556363A (en) * 1982-06-21 1985-12-03 Nippondenso Co., Ltd. Pumping apparatus
US4489951A (en) * 1983-08-17 1984-12-25 Ebara Corporation Mechanical seal
US5074747A (en) * 1988-07-13 1991-12-24 Osaka Vacuum, Ltd. Vacuum pump
US5160250A (en) * 1988-07-13 1992-11-03 Osaka Vacuum, Ltd. Vacuum pump with a peripheral groove pump unit
US5217346A (en) * 1988-07-13 1993-06-08 Osaka Vacuum, Ltd. Vacuum pump
US5219269A (en) * 1988-07-13 1993-06-15 Osaka Vacuum, Ltd. Vacuum pump
US5221179A (en) * 1988-07-13 1993-06-22 Osaka Vacuum, Ltd. Vacuum pump
DE4415566A1 (en) * 1994-05-03 1995-11-09 Sero Pumpenfabrik Gmbh Self=priming multistep rotary pump
DE4415566C2 (en) * 1994-05-03 1999-02-18 Sero Pumpenfabrik Gmbh Side channel pump
US6164656A (en) * 1999-01-29 2000-12-26 General Electric Company Turbine nozzle interface seal and methods
US20050249617A1 (en) * 2004-05-10 2005-11-10 Visteon Global Technologies, Inc. Fuel pump having single sided impeller
US20050249581A1 (en) * 2004-05-10 2005-11-10 Visteon Global Technologies, Inc. Fuel pump having single sided impeller
US7008174B2 (en) 2004-05-10 2006-03-07 Automotive Components Holdings, Inc. Fuel pump having single sided impeller
US7267524B2 (en) 2004-05-10 2007-09-11 Ford Motor Company Fuel pump having single sided impeller
US20070160465A1 (en) * 2006-01-10 2007-07-12 Roudnev Aleksander S Flexible floating ring seal arrangement for rotodynamic pumps
US7429160B2 (en) * 2006-01-10 2008-09-30 Weir Slurry Group, Inc. Flexible floating ring seal arrangement for rotodynamic pumps
CN101371047B (en) * 2006-01-10 2011-05-25 威尔斯拉里集团公司 Flexible floating ring seal arrangement for rotodynamic pumps
US20140227086A1 (en) * 2013-02-11 2014-08-14 Fluid Equipment Development Company, Llc Method And Apparatus For Sealing A Rotating Machine Using Floating Seals
US9562539B2 (en) * 2013-02-11 2017-02-07 Fluid Equipment Development Company, Llc Method and apparatus for sealing a rotating machine using floating seals

Similar Documents

Publication Publication Date Title
US2396319A (en) Pump
US2535695A (en) Motor pump unit
US2056553A (en) Pump
US2429978A (en) Centripetal-centrifugal pump
US2407987A (en) Multistage centrifugal pump
US2374122A (en) Double case pump
US1499056A (en) Centrifugal pump
US2835203A (en) Pump impeller
US2003350A (en) Pump
US1457536A (en) Centrifugal compressor
GB492854A (en) Improvements in or relating to throw pumps or centrifugal pumps
US3154240A (en) Pumping device
US1496222A (en) Sealing means for rotary pumps
US1665687A (en) Pump
US2422763A (en) Centrifugal compressor
US2876946A (en) Centrifugal blower
US2312837A (en) Pump
US1229274A (en) Duplex centrifugal pump.
US2034549A (en) Pump
US2574724A (en) Multistage rotary pump
US2321190A (en) Rotary pump
US2207220A (en) Series-parallel centrifugal pump
US1661325A (en) Rotary pump
US2319230A (en) Centrifugal pump
US1805765A (en) Centrifugal pump