EP0286809B1 - Cavitation-resistant inducer - Google Patents

Cavitation-resistant inducer Download PDF

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Publication number
EP0286809B1
EP0286809B1 EP19880102746 EP88102746A EP0286809B1 EP 0286809 B1 EP0286809 B1 EP 0286809B1 EP 19880102746 EP19880102746 EP 19880102746 EP 88102746 A EP88102746 A EP 88102746A EP 0286809 B1 EP0286809 B1 EP 0286809B1
Authority
EP
European Patent Office
Prior art keywords
inducer
hub
blades
pump
outer periphery
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
Application number
EP19880102746
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0286809A2 (en
EP0286809A3 (en
Inventor
Charlton Dunn (Nmn)
Maria Romaniuk Subbaraman
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.)
Boeing North American Inc
Original Assignee
Rockwell International Corp
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 Rockwell International Corp filed Critical Rockwell International Corp
Publication of EP0286809A2 publication Critical patent/EP0286809A2/en
Publication of EP0286809A3 publication Critical patent/EP0286809A3/en
Application granted granted Critical
Publication of EP0286809B1 publication Critical patent/EP0286809B1/en
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/18—Rotors
    • F04D29/181—Axial flow rotors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/18—Rotors
    • F04D29/22—Rotors specially for centrifugal pumps
    • F04D29/2261—Rotors specially for centrifugal pumps with special measures
    • F04D29/2277—Rotors specially for centrifugal pumps with special measures for increasing NPSH or dealing with liquids near boiling-point

Definitions

  • the present invention relates to an inducer (for axial and centrifugal pumps) in accordance with the preamble of the main claim.
  • an inducer is known from DE-A-2 116 091 and GB-A-684 230.
  • the present invention provides an inducer capable of operating over a wider range of flow rates with less risk of cavitation and a higher efficiency than would otherwise be possible.
  • Yet another object of the present invention is to provide a shrouded inducer which will operate over a wide range of flow rates and maintain a high efficiency.
  • Still another object of the invention is to provide such a shrouded inducer which is readily fabricable without undue cost.
  • the inducer of the present invention comprises a, hub rotatably mounted within a pump housing, a plurality of substantially helical blades extending radially outward from the hub and a wall member extending about and encompassing an outer periphery of the substantially helical blades.
  • the wall member could be an inner surface of the pump housing or in accordance with the preferred embodiment would comprise a shroud extending about the outer periphery and affixed to ends of the substantially helical blades.
  • the essence of the present invention is that adjacent pairs of blades, the wall member and hub form a substantially rectangular cross-sectional flow area, the cross-sectional flow area decreasing from the inlet (suction) end of the inducer to a discharge (pressure) end.
  • the cross-sectional flow area decreases substantially linearly.
  • a typical shrouded inducer-centrifugal pump assembly 10 which includes a housing 12, a drive shaft 14 extends into housing 12 and is rotatably supported by bearings not shown.
  • a centrifugal impeller 16 located within housing 12 is affixed to drive shaft 14 for receiving rotational forces therefrom and imparting rise in pressure to any fluid passing through housing 12.
  • a shrouded inducer 18 is affixed to a hub end 20 of shaft 14 for increasing the pressure of incoming fluid before it enters impeller 16. Alternatively of course shrouded inducer 18 could be attached directly to impeller 16.
  • Inducer 18 comprises at least one and preferably a plurality of inducer blades 22 which extend radially outward and terminate in a substantially cylindrical shroud member 24. As depicted shrouded inducer assembly 18 is located within a cavity 28 defined by an inner surface 30 of housing 12, which inner surface would form an outer wall extending about an outer periphery of inducer blades 22 if an unshrouded inducer were utilized.
  • Fig. 2 therein is depicted an end view of a preferred form of inducer for the practice of the present invention. Specifically, one having four equally spaced, substantially helical blades which extend approximately 180° about an outer periphery of hub end 20. As depicted, straight radial uncanted blades are shown for simplicity. The leading edge shape of the blades and the front view of the inducer would be equally applicable to a prior art inducer as well as that of the present invention, as is also the case with the unwrapped top view shown in Figure 3. Therein, again in the interest of simplicity, the inducer blades are shown for a simple, straight, constant blade angle.
  • the inducer of the present invention differs from the prior art designs in the shape of the flow passages and the hub contour which is more readily seen in the following figures.
  • Fig. 4 therein is depicted a cross-section of fluid passageway of an inducer constructed in accordance with the present invention. It will be seen that the height of the blade and passage diminishes in a substantially linear fashion in the direction of flow. Further, this same profile would apply for any location of the cross-section within the passageway between the blade pressure side of one blade and an adjacent suction side of another blade. It is a key aspect of the present invention that the blade height reduction along the flow length is basically linear with smooth transitions near the passage entrance and exit at a selected hub diameter. The distinction between the prior art and the current invention is best seen and illustrated in Figs. 5 and 7 (prior art) and Figs. 6 and 8 (current invention).
  • the inducer of the present invention utilizes a somewhat irregular or "ratchet shaped" hub.
  • This hub shape will, of course, result in some higher stress levels compared to the axisymetric hub of the comparable prior art inducer.
  • This disadvantage is offset by the advantages gained by the uniform fluid passageway.
  • the passageway of an inducer constructed in accordance with the present invention is a regular, rectangular shape with suction and pressure sides of the blades of equal height.
  • fluid passing therethrough travels in a substantially axial direction with minimal cross-currents (secondary flow) such as would be experienced with the prior art inducers. It is this uniformly diminishing cross-sectional flow area as indicated by Fig. 4 that permits the inducer of the present invention to operate over a wider range of flow rates without cavitation than would otherwise be possible.
  • An object of the present invention is to improve suction performance. Improved suction performance can, in general, be obtained by keeping the static pressure in the inducer inlet region high through opening up the fluid passage area (Section Line A between blades 22 B and 22 C , Figure 7 vs blades 22 ⁇ B and 22 ⁇ C in Figure 8).
  • the rectangular throat shape compared to the conventional passage, has a larger area in the blade suction side region - where the cavitation susceptible, low pressure, high velocity flow normally occurs. This local increase in the flow passage area leads to a local slow down of fluid velocity and a static pressure increase - which in turn leads directly to improved suction performance.
  • the blade height on the pressure side (P) is the same for both channels and is set by the hub inlet and blade tip diameters.
  • the inducer of the present invention is more readily fabricated at a lesser cost than those of the prior art.
  • the fluid passage machining is usually performed from both the inlet and discharge ends of the passage.
  • the rectangular shape of the passageway of an inducer in accordance with the present invention allows use of larger cutters, thus significantly reducing machining time and cost.
  • the rectangular shape also simplifies the electrode shape and the forming operations in fabrication, for example, by EDM.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
EP19880102746 1987-04-10 1988-02-24 Cavitation-resistant inducer Expired EP0286809B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US3662787A 1987-04-10 1987-04-10
US36627 2005-01-13

Publications (3)

Publication Number Publication Date
EP0286809A2 EP0286809A2 (en) 1988-10-19
EP0286809A3 EP0286809A3 (en) 1988-11-02
EP0286809B1 true EP0286809B1 (en) 1991-10-16

Family

ID=21889685

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19880102746 Expired EP0286809B1 (en) 1987-04-10 1988-02-24 Cavitation-resistant inducer

Country Status (3)

Country Link
EP (1) EP0286809B1 (ja)
JP (1) JPS63263300A (ja)
DE (1) DE3865490D1 (ja)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2704992B2 (ja) * 1991-03-29 1998-01-26 科学技術庁航空宇宙技術研究所長 高速ポンプのインデューサ装置
JP4874243B2 (ja) * 2004-07-07 2012-02-15 パイロテック インコーポレイテッド 溶融金属ポンプ
CN112855608B (zh) * 2021-01-28 2022-07-01 浙江理工大学 一种配合有支撑柱的轮毂诱导轮
CN114922844A (zh) * 2022-05-07 2022-08-19 安徽南方化工泵业有限公司 一种磁力泵的叶轮结构

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE505656A (ja) * 1950-09-08
US3163119A (en) * 1961-07-03 1964-12-29 North American Aviation Inc Inducer
US3442220A (en) * 1968-08-06 1969-05-06 Rolls Royce Rotary pump
US3697190A (en) * 1970-11-03 1972-10-10 Walter D Haentjens Truncated conical drag pump
DE2116091A1 (de) * 1971-04-02 1972-10-19 Robert Bosch Gmbh, 7000 Stuttgart Vorrichtung zum Fördern von Flüssigkeiten
US3751178A (en) * 1971-10-06 1973-08-07 Warren Pumps Inc Pump

Also Published As

Publication number Publication date
EP0286809A2 (en) 1988-10-19
DE3865490D1 (de) 1991-11-21
EP0286809A3 (en) 1988-11-02
JPS63263300A (ja) 1988-10-31

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