US3323465A - Inlet piece for a centrifugal pump - Google Patents

Inlet piece for a centrifugal pump Download PDF

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Publication number
US3323465A
US3323465A US447749A US44774965A US3323465A US 3323465 A US3323465 A US 3323465A US 447749 A US447749 A US 447749A US 44774965 A US44774965 A US 44774965A US 3323465 A US3323465 A US 3323465A
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US
United States
Prior art keywords
pump
chamber
liquid
impeller
inlet
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
US447749A
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English (en)
Inventor
Cornelis R Stillebroer
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.)
Shell USA Inc
Original Assignee
Shell Oil 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 Shell Oil Co filed Critical Shell Oil Co
Application granted granted Critical
Publication of US3323465A publication Critical patent/US3323465A/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • F04D29/22—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
    • 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
    • F04D29/66—Combating cavitation, whirls, noise, vibration or the like; Balancing
    • F04D29/669—Combating cavitation, whirls, noise, vibration or the like; Balancing especially adapted for liquid pumps

Definitions

  • Centrifugal pumps are used extensively for pumping liquids.
  • the pressure at the delivery side is obtained by imparting a centrifugal acceleration to the liquid means of an impeller.
  • the liquid In the inlet opening of the pump, which is located in the center of the impeller, the liquid consequently experiences a pressure drop.
  • NPSH net positive suction head
  • the NPSH can be obtained by a variety of methods.
  • a method often applied is one in which the vessel from which liquid is drawn is placed at a sufficiently high level.
  • this solution is often uneconomical, particularly when the vapor pressure of the liquid is high.
  • Another solution is the use of a separate pump at the inlet side of the centrifugal pump.
  • this solution is expensive since it requires an additional pump and the power to operate it.
  • centrifugal pump could be provided with impeller blades that have been axially lengthened towards the inlet side.
  • the separate pump for producing the required NPSH is attached to and driven 'by the centrifugal pump.
  • a rotary motion will be imparted to the liquid which may be sulficient to prevent cavitation.
  • This invention solves the above problems by providing a centrifugal pump having impeller blades extending into an inlet piece which inlet piece consists of a cylindrical rotation chamber positioned coaxial with the pump shaft and having a closed lateral surface.
  • the diameter of the chamber is approximately the same diameter as the inlet Opening of the pump housing.
  • the chamber is also provided with a liquid supply line having an outlet located coaxially in the end wall of the chamber. The cross-sectional area of the supply line is smaller than the area of the inlet opening of the pump housing.
  • FIGURE 1 is a vertical section of a centrifugal pump showing one embodiment of this invention
  • FIGURE 2 is a vertical section of a centrifugal pump inlet piece showing a second embodiment of the invention
  • FIGURE 3 is a vertical section of a centrifugal pump inlet piece showing a third embodiment of this invention.
  • FIGURE 4 is a vertical section of a centrifugal pump inlet piece showing an embodiment of this invention incorporating a gas discharge outlet and a control system therefor.
  • the inlet piece 4 constructed according to this invention.
  • the inlet piece consists of a cylindrical chamber 6 having a diameter at least equal to the diameter of the inlet opening 5 of the pump housing 2.
  • the pump shown is provided with a shaft 1 journaled in the pump housing 2.
  • the impeller 3 is secured to the shaft 1 and disposed within the housing 2.
  • the cylindrical chamber 6 is connected to the inlet opening 5 in the pump housing 2 and that has the same diameter as the cylindrical chamber 6.
  • a liquid supply pipe 8 communicates with the center of the closed end piece 7 of the cylinder 6.
  • the cylinder 6 and supply pipe 8 are disposed coaxially with respect to the axis of rotation 1 of the centrifugal pump impeller 3.
  • An inlet piece of this type may for instance consist of two pipe sections differing in diameter, which are welded or coupled together, the liquid being supplied through the smaller pipe.
  • the rotary motion of the liquid in the inlet piece creates a pressure in the liquid with the pressure being directed radially outwards.
  • the pressure is a highest adjacent the wall of the cylinder 6 and lowest at the center of the cylinder 6.
  • the outlet of the liquid supply device 8 is located centrally in the end piece 7 of the inlet piece 4, hence the entering liquid encounters little or no counterpressure. It is thus possible for the lateral wall of the cylinder 6 to be designed with sufiicient strength to resist the pressure created.
  • the liquid under pressure cannot be forced upward because the area of the outlet of the liquid supply device is smaller than the area of the inlet opening of the pump housing.
  • the opening of the inlet piece of the pump is made as large as possible, for example, equal to the inlet opening of the pump housing, the highest possible pressure will be created.
  • the outlet of the liquid supply device should be as small as possible and still supply the required quantity of liquid to the pump. It is possible for the inlet piece to form an integral part of the pump housing or as a separate piece fastened to the pump housing.
  • FIGURE 2 there is shown a second embodiment of this invention which consists of a cylindrical chamber 10 with a diameter at least equal to the diameter of the inlet opening of the pump housing.
  • r cylindrical chamber is formed by a cylinder 14 that is closed at one end and fitted with a partition 11 perpendicular to the center line of the cylinder. In the center of the partition 11 there is located an opening 12 that forms the outlet of the liquid supply pipe 13. The cylinder 14 on the upstream side of the partition 11 communicates with the liquid supply pipe 13.
  • FIG- URE 2 The simplest case of the embodiment shown in FIG- URE 2 would consist of a wide inlet pipe in which there is located a transverse partition with a central aperture.
  • FIG- URE 3 A modification of this embodiment is shown in FIG- URE 3 where an inlet pipe 17 is provided with a diameter equal to the diameter of the inlet opening of the pump.
  • the inlet pipe 17 is provided with a constriction 16 having a small central opening 15.
  • the opening 15 should be similar in size to the openings 9 and 12 in FIGURES 1 and 2.
  • FIGURES 1, 2 and 3 all improve the NPSH of the centrifugal pump by causing the liquid in the cylindrical chamber to rotate.
  • the rotation of the liquid can be increased by placing the liquid inlet to the cylindrical chamber tangential to the wall of the chamber as shown in FIGURE 2.
  • the cost of the modifications required of the conventional centrifugal pump is small.
  • the embodiments shown in FIGURES l, 2 and 3 utilize a pump having a vertical shaft, the invention can also be incorporated into pumps having a horizontal shaft.
  • One method for removing the gas from the pump inlet is to provide a discharge pipe that extends into the gas core at the pump inlet.
  • the discharge pipe may extend outside the supply line for the pump. In some cases it may be desirable to extend the discharge pipe to the storage tank to obtain a pressure equilibrium between the pump and the storage tank.
  • centrifugal pumps for liquids are used in systems having a sufficient supply of the liquid. That is to say, as long as the pump is running, any limitation on the rate at which the liquid is pumped is caused by the pump or by the liquid discharge, not by a reduction in the liquid supply.
  • Liquids whose volume rate of flow variesand whose flow may even be temporarily stopped cannot be properly pumped with a centrifugal pump without special equipment. In cases where the liquid supply is interrupted, the impeller, or part of the impeller, may run dry or vapor bubbles may be liberated. Consequently, there is a risk of damage to the impeller.
  • FIGURE 4 shows a gas discharge pipe 23, which protrudes through the outlet 24 in the partition 25 between the liquid supply chamber 26 and the cylindrical rotation chamber 27.
  • the pipe 23 is connected to the space 29 over the liquid 30 in a storage vessel 39.
  • Gauge 31 is a differential pressure gauge which measures the difference in pressure between the liquid present near the wall and the liquid being present closer to the center line of the chamber 27.
  • the signal from gauge 31 passes to controller 32 which compares this signal with a set value and generates an output signal.
  • the output signal is supplied to a valve 33 in the discharge line of the pump.
  • the controller 32 controls the valve 33 to maintain the differential pressure measured by the gauge 31 within present limits.
  • the preset limits are chosen to insure that the impeller of the pump remains filled with liquid.
  • the invention thus provides for a control system to be applied to a pump provided with an inlet piece according to the invention, by which the pump may successfully pump liquids whose volume rate of flow varies.
  • the discharge line of the pump contains a control device that is positioned by the output of a controller.
  • the controller input is connected to a differential pressure I gauge that measures the liquid pressure at the aperture of the impeller.
  • the flow control device may be a valve in the discharge line that will be closed when the measured liquid pressure or the measured pressure difference in the liquid becomes too low as compared with the set value of the controller.
  • This set value is selected to ensure there always remains sufiicient liquid in the chamber 27 for the NPSH in the cylindrical rotation chamber when the liquid supply is insufficient and even when the supply stops altogether. In the latter case the valve referred to will be fully closed. When the liquid supply is resumed this liquid is pumped immediately, since the pump is in operation.
  • a centrifugal pump for liquids comprising:
  • a pump chamber having inlet and outlet openings
  • impeller said impeller being mounted on a shaft and disposed for rotation in said pump chamber, the blades of said impeller in addition extending into the inlet opening of said pump chamber;
  • rotation chamber having a lateral partition formed therein and disposed normal to the center line of the chamber, said partition having a central opening, said rotation chamber having approximately the same diameter as the inlet opening of said pump chamber, said rotation chamber in addition being connected to the inlet opening of said pump chamber;
  • a gas discharge tube said tube being disposed on the center line of the impeller and extending through said partition, the diameter of said tube being less than the diameter of the opening in the partition;
  • a pump according to claim 1 wherein the supply line of the pump is connected tangentially to the Wall of the rotation chamber upstream of said partition, the direction of said tangential connection being such that the direction of the motion of the liquid leaving the tangential connection is the same as that of the impeller of the pump.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
US447749A 1964-04-17 1965-04-13 Inlet piece for a centrifugal pump Expired - Lifetime US3323465A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL6404199A NL6404199A (enrdf_load_stackoverflow) 1964-04-17 1964-04-17

Publications (1)

Publication Number Publication Date
US3323465A true US3323465A (en) 1967-06-06

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Family Applications (1)

Application Number Title Priority Date Filing Date
US447749A Expired - Lifetime US3323465A (en) 1964-04-17 1965-04-13 Inlet piece for a centrifugal pump

Country Status (3)

Country Link
US (1) US3323465A (enrdf_load_stackoverflow)
GB (1) GB1079635A (enrdf_load_stackoverflow)
NL (1) NL6404199A (enrdf_load_stackoverflow)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3597904A (en) * 1968-05-14 1971-08-10 Celleco Ab Apparatus for liquid-gas separation
JPS4872766A (enrdf_load_stackoverflow) * 1971-09-27 1973-10-01
DE3111225A1 (de) 1980-04-07 1982-01-14 A. Ahlström Oy, 29600 Noormarkku "vorrichtung und verfahren zum trennen eines gases von einer fasersuspension"
JPS5927084U (ja) * 1982-08-05 1984-02-20 三洋電機株式会社 脱水洗濯機の制動装置
US4435193A (en) 1980-04-07 1984-03-06 Kamyr Ab Controlling operation of a centrifugal pump
US4637778A (en) * 1983-12-12 1987-01-20 Textron Inc. Self-priming diffuser type centrifugal pump
US4708593A (en) * 1986-02-28 1987-11-24 Robinson Industries, Inc. Surgeless combustion air blower
EP0317687A1 (de) * 1987-11-26 1989-05-31 Cryomec AG Zentrifugalpumpe für cryogene Fluida
US4981154A (en) * 1990-01-30 1991-01-01 Hollister, Inc. Fluid flow control device
US5106456A (en) * 1988-01-05 1992-04-21 A. Ahlstrom Corporation Method and apparatus for facilitating the discharge of pulp
US5413460A (en) * 1993-06-17 1995-05-09 Goulds Pumps, Incorporated Centrifugal pump for pumping fiber suspensions
US5431546A (en) * 1993-08-23 1995-07-11 Liquid Carbonic Corporation Apparatus for intermittent transfer of fluid having vapor trap seal and vapor escape means
AT402842B (de) * 1986-10-06 1997-09-25 Ingersoll Rand Co Vorrichtung zum pumpen von pülpe
US5861052A (en) * 1993-12-23 1999-01-19 Pom Technology Oy Ab Apparatus and process for pumping and separating a mixture of gas and liquid
US6723205B1 (en) 1999-06-03 2004-04-20 Fom Technology Oy Ab Degassing centrifugal apparatus with energy recovery, process for degassing a fluid and process for producing paper or board
EP2072823A3 (de) * 2007-12-18 2014-06-25 Wilo Ag Kreiselpumpe mit Entlüftung
RU2580561C1 (ru) * 2015-04-29 2016-04-10 ООО "Ассоциация инженеров и учёных по водоснабжению и водоотведению" Система перекачки осадков
RU2596083C1 (ru) * 2015-07-08 2016-08-27 Государственное Унитарное Предприятие "Водоканал Санкт-Петербурга" Система откачки осадков сточных вод

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2558840C2 (de) * 1975-12-27 1983-03-24 Klein, Schanzlin & Becker Ag, 6710 Frankenthal Einrichtung zur Verminderung des Kavitationsverschleisses
SE420230C (sv) * 1980-10-20 1987-11-16 Sala International Ab Anordning for pumpning av skummande vetskor
CN108050109B (zh) * 2018-01-08 2024-08-23 山西天海给排水设备有限公司 一种抑制汽蚀的离心泵及其工作方法

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1465097A (en) * 1923-08-14 Regulating centkieugal pumps
US1866064A (en) * 1928-01-30 1932-07-05 Stratford Charles Walcott Hot oil pump
GB461227A (en) * 1936-06-20 1937-02-12 Petr Dmitrevskij Improvements in or relating to the conveyance of boiling or gaseous liquids
US2278397A (en) * 1938-02-25 1942-03-31 Messerschmitt Boelkow Blohm Liquid pump and gas separator
FR893320A (fr) * 1942-02-14 1944-06-06 Aschaffenburger Zellstoffwerke Procédé et installation pour l'aspiration et la transmission simultanées d'air et d'eau par une pompe centrifuge débitant du liquide
GB686102A (en) * 1949-09-09 1953-01-21 Self Priming Pump & Eng Co Ltd Improvements in or relating to pumps
GB735866A (en) * 1952-02-15 1955-08-31 Rolls Royce Improvements in or relating to fuel pumps and systems
US2896543A (en) * 1956-12-20 1959-07-28 Ethridge F Ogles Irrigation ditch pumping apparatus with reversible impeller
US3203354A (en) * 1962-03-26 1965-08-31 Thiokol Chemical Corp Pump

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1465097A (en) * 1923-08-14 Regulating centkieugal pumps
US1866064A (en) * 1928-01-30 1932-07-05 Stratford Charles Walcott Hot oil pump
GB461227A (en) * 1936-06-20 1937-02-12 Petr Dmitrevskij Improvements in or relating to the conveyance of boiling or gaseous liquids
US2278397A (en) * 1938-02-25 1942-03-31 Messerschmitt Boelkow Blohm Liquid pump and gas separator
FR893320A (fr) * 1942-02-14 1944-06-06 Aschaffenburger Zellstoffwerke Procédé et installation pour l'aspiration et la transmission simultanées d'air et d'eau par une pompe centrifuge débitant du liquide
GB686102A (en) * 1949-09-09 1953-01-21 Self Priming Pump & Eng Co Ltd Improvements in or relating to pumps
GB735866A (en) * 1952-02-15 1955-08-31 Rolls Royce Improvements in or relating to fuel pumps and systems
US2896543A (en) * 1956-12-20 1959-07-28 Ethridge F Ogles Irrigation ditch pumping apparatus with reversible impeller
US3203354A (en) * 1962-03-26 1965-08-31 Thiokol Chemical Corp Pump

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3597904A (en) * 1968-05-14 1971-08-10 Celleco Ab Apparatus for liquid-gas separation
JPS4872766A (enrdf_load_stackoverflow) * 1971-09-27 1973-10-01
DE3111225A1 (de) 1980-04-07 1982-01-14 A. Ahlström Oy, 29600 Noormarkku "vorrichtung und verfahren zum trennen eines gases von einer fasersuspension"
US4410337A (en) * 1980-04-07 1983-10-18 A. Ahlstrom Osakeyhtio Method and an apparatus for separating a gas from a fibre suspension
US4435193A (en) 1980-04-07 1984-03-06 Kamyr Ab Controlling operation of a centrifugal pump
DE3153358C2 (enrdf_load_stackoverflow) * 1980-04-07 1988-11-10 A. Ahlstroem Oy, Noormarkku, Fi
JPS5927084U (ja) * 1982-08-05 1984-02-20 三洋電機株式会社 脱水洗濯機の制動装置
US4637778A (en) * 1983-12-12 1987-01-20 Textron Inc. Self-priming diffuser type centrifugal pump
US4708593A (en) * 1986-02-28 1987-11-24 Robinson Industries, Inc. Surgeless combustion air blower
AT402842B (de) * 1986-10-06 1997-09-25 Ingersoll Rand Co Vorrichtung zum pumpen von pülpe
EP0317687A1 (de) * 1987-11-26 1989-05-31 Cryomec AG Zentrifugalpumpe für cryogene Fluida
US5106456A (en) * 1988-01-05 1992-04-21 A. Ahlstrom Corporation Method and apparatus for facilitating the discharge of pulp
US4981154A (en) * 1990-01-30 1991-01-01 Hollister, Inc. Fluid flow control device
US5413460A (en) * 1993-06-17 1995-05-09 Goulds Pumps, Incorporated Centrifugal pump for pumping fiber suspensions
US5431546A (en) * 1993-08-23 1995-07-11 Liquid Carbonic Corporation Apparatus for intermittent transfer of fluid having vapor trap seal and vapor escape means
US5522709A (en) * 1993-08-23 1996-06-04 Liquid Carbonic Corporation Apparatus for intermittent transfer of fluid having vapor trap seal and vapor escape means
US5861052A (en) * 1993-12-23 1999-01-19 Pom Technology Oy Ab Apparatus and process for pumping and separating a mixture of gas and liquid
US6723205B1 (en) 1999-06-03 2004-04-20 Fom Technology Oy Ab Degassing centrifugal apparatus with energy recovery, process for degassing a fluid and process for producing paper or board
US6827820B1 (en) 1999-06-03 2004-12-07 Pom Technology Oy Ab Degassing centrifugal apparatus, process for pumping and degassing a fluid and process for producing paper or board
EP2072823A3 (de) * 2007-12-18 2014-06-25 Wilo Ag Kreiselpumpe mit Entlüftung
RU2580561C1 (ru) * 2015-04-29 2016-04-10 ООО "Ассоциация инженеров и учёных по водоснабжению и водоотведению" Система перекачки осадков
RU2596083C1 (ru) * 2015-07-08 2016-08-27 Государственное Унитарное Предприятие "Водоканал Санкт-Петербурга" Система откачки осадков сточных вод

Also Published As

Publication number Publication date
NL6404199A (enrdf_load_stackoverflow) 1965-10-18
GB1079635A (en) 1967-08-16

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