US3837762A - Pumps - Google Patents

Pumps Download PDF

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Publication number
US3837762A
US3837762A US00365163A US36516373A US3837762A US 3837762 A US3837762 A US 3837762A US 00365163 A US00365163 A US 00365163A US 36516373 A US36516373 A US 36516373A US 3837762 A US3837762 A US 3837762A
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US
United States
Prior art keywords
chamber
diffuser
outlet pipe
pump
pump assembly
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
US00365163A
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English (en)
Inventor
A Lee
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.)
English Electric Co Ltd
Original Assignee
English Electric Co Ltd
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 English Electric Co Ltd filed Critical English Electric Co Ltd
Application granted granted Critical
Publication of US3837762A publication Critical patent/US3837762A/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
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
    • F04D29/44—Fluid-guiding means, e.g. diffusers
    • F04D29/445—Fluid-guiding means, e.g. diffusers especially adapted for liquid pumps
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D7/00—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts
    • F04D7/02—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts of centrifugal type
    • F04D7/08—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts of centrifugal type the fluids being radioactive

Definitions

  • ABSTRACT A pump assembly having a chamber into which a pump is arranged to discharge, and a plurality of outlet pipes each having one end extending into the chamber, the wall of each outlet pipe at said one end being of streamline form, and the part of each pipe extending away from said one end being in the form of a diffuser of gradually increasing internal cross-sectional area with increasing distance from the said one end.
  • a pump assembly comprises a pump, achamber into which the pump is arranged to discharge, and at least one outlet pipe in communication at one of its ends with the interior of the chamber, the wall of the/or each outlet pipe at the said one of its ends being of streamline form and a part of the/or each pipe extending away from the said one end thereof being in the form of a diffuser of gradually increasing internal cross-sectional area with increasing distance from the said one end of the pipe.
  • the pump comprises a rotary centrifugal impeller and an annular axial diffuser having a first end arranged to receive pumped fluid from the impeller and a second end, of greater annular cross-sectional area than the first end, opening into the said chamber.
  • the diffuser whose second end opens into the chamber, itself constitutes a peripheral wall section of the chamber, into which its said second end opens peripherally, and the or each outlet pipe extends into the chamber, in the axial direction of the diffuser, with its said one end directed oppositely to and away from the said second end of the diffuser, whereby fluid flowing from the pump flows in one axial direction in the diffuser and in the or each outlet pipe but in the opposite direction whilst flowing, within the chamber, from the diffuser to the outlet pipe or pipes.
  • FIG. 1 is a view, partly in axial section, of the pump assembly
  • FIG. 2 is an axial sectional view, on a larger scale; of part of the pump assembly shown in FIG. 1.
  • the pump assembly shown in the drawings and indicated generally by the reference 11 is intended for use in circulating molten sodium as the reactor primary coolant in, for example, a civil fast reactor, and as shown in FIG. 1 is mounted vertically with its upper end secured in sealing engagement in an aperture 12 in a reactor containment vessel 13, with its lower end immersed below the surface level 14 of a reservoir of mo]- ten sodium 15 contained within the vessel 13.
  • the pump assembly 11 comprises an electric motor 16 for rotating a shaft 17 on the lower end of which is secured an impeller 18 provided with vanes 19. Rotation of the shaft 17 and impeller 18 impels molten sodium, in an annular duct 20 defined by fixed parts of the pump assembly and provided with fixed vanes 21 and 22, centrifugally outwards past the vanes 22.
  • the duct 20 is below the surface level 14 of the sodium 15, and is thus kept filled with sodium which enters it past the vanes 21.
  • the shaft 17 is supported near its lower end by a bearing 23 mounted by means of struts 24.
  • the bearing 23 may, as shown, be a hydrostatic bearing and in that case it may, as shown, he supplied with molten sodium under pressure via a pipe 25 which bleeds off a small proportion of the sodium in the duct 20 in the vicinity of the vanes 22 and supplies it via one of the struts 24 to the bearing 23.
  • This sodium then flows from the bearing into the space 26 surrounding the bearing and the shaft 17, this space being in any case filled with sodium up to the surface level 14 because it is open to the sodium 15 through apertures 27.
  • the sodium impelled past the vanes 22 passes through an annular axial diffuser having coaxial outer end inner walls 28 and 29 and fixed vanes 30, the sodium entering this diffuser at a first, upper end thereof and being discharged therefrom at a second, lower, end thereof which is of greater annular cross-sectional area.
  • the pump assembly as described in the preceding paragraph- is of known kind, but in accordance with the present invention it is provided, as described below, with a chamber into which it discharges and with one or (as shown in the drawings) more outlet pipes in communication with the interior of the chamber.
  • the said chamber is defined in part by the diffuser, which itself constitutes a peripheral wall section thereof, and is closed at its upper end by fixed parts of the pump assembly in the vicinity of the impeller 18 thereof.
  • the chamber 31 is closed by a dished or bowl-shaped plate 32 which is secured in sealed manner, for example by welding, to the lower end of the outer wall 28 of the diffuser.
  • the plate 32 is apertured to receive, in sealed engagement therewith, four outlet pipes 33 which extend in the axial direction and project upwardly into the chamber 31 with an end 34 of each pipe in communication with the interior of the chamber.
  • each outlet pipe at its end 34, is of streamline form so that as sodium flows into the pipes 33 from the chamber 31 there is little or no separation of the fluid flow from the pipe walls.
  • the illustrated pump assembly is shown mounted in a nuclear reactor; and the outlet pipes 33 would convey the pumped liquid sodium from the pump assembly to a core of the reactor, where it would be distributed to nuclear fuel elements within the core.
  • Fourpipes 33 are associated with the pump assembly as a safety factor, so that in the event of a failure of one of the pipes a reduced but still sufficient, proportion of the output of the pump assembly will continue to reach the fuel elements. It will be understood that in other applications in which such safety considerations do not apply a pump assembly in accordance with the invention might be provided with less outlet pipes and perhaps with only one.
  • a further consideration when (as would be the case in a nuclear reactor) a plurality of pumps are operating in parallel in a fluid-flow system is that it will usually be desirable or essential that even a complete failure of one of the pumps should not result in the system as a whole being subjected to a leakage so serious as to prevent the remaining pumps from maintaining a reduced but still satisfactory supply to the intended destination of the pumped fluid; and the pump outlet means according to the invention enables this desirable object to be achieved, as will not be explained.
  • the sodium impelled by the impeller 18 enters the diffuser at relatively high speed and, as it passes from the upper end of the diffuser to the lower end thereof which is of greater annular cross-sectional area, its speed is reduced and part of its kinetic energy is converted, almost without loss, into pressure energy.
  • the streamline form of the pipe walls at their ends 34 ensures, however, that the flow is substantially nonturbulent and that the conversion of pressure energy to kinetic energy is effected with little loss of energy.
  • the provision of the pipe sections 35 in the form of diffusers then provides a smooth transition, again with negligible energy loss, from the ends 34 to the main runs of the pipes 33 which are of wider bore and in which, accordingly the kinetic energy of the flowing sodium is less again-In the event of failure of one of several pumps 11 acting in parallel, however (or, equally, in the event that the chamber 31 associated with one of several such pumps becomes fractured so that the output from the pump is lost by leakage), the flow of sodium in the pipes 33 associated with that pump and that chamber 31 will be reversed due to the pressure from the outputs of the other pumps; and it is important for safety reasons that this reverse flow should be minimised so as not to constitute a serious leakage of the outputs from the other pumps.
  • the provision of the chamber 31 between the pump and the pipes 33 also confers another benefit, of a different kind. It is well known that acoustic waves are transmitted with little attenuation along a fluid in a pipe of constant or only slightly varying cross section, and this could lead, in a reactor coolant system, to noise (including high frequency noise) generated in a pump of the system producting, in other parts of the reactor, vibrations which could be dangerous or could interfere with instrumentation of the reactor.
  • one method of detecting failed fuel elements in a reactor is by means of hydrophones, in the fuel channels, which detect the noise from boiling of the sodium coolant in the vicinity of a ruptured fuel element container.
  • a pump assembly comprising:
  • each outlet pipe extending away from the said one end thereof being in the form of a diffuser of gradually increasing internal cross-sectional area with increasing distance from the said one end of the outlet pipe;
  • each outlet pipe opening abruptly into the much greater cross-sectional area of the chamber so that the arrangement of outlet pipes and chamber acts as a fluid diode.
  • a pump assembly as claimed in claim 2 wherein the second end of said annular axial diffuser constitutes a peripheral wall section of said chamber into which its second end opens peripherally, and each outlet pipe extends into the chamber in the axial direction of the said annular axial diffuser with its said one end directed oppositely to and away from the second end of the annular axial diffuser, whereby fluid flowing from the impeller flows in one axial direction through the annular axial diffuser and through each difiuser formed by a part of an outlet pipe, but flows in the opposite axial direction while flowing, within said chamber, from said annular axial diffuser to each diffuser formed by a part of an outlet pipe.
  • a pump assembly as claimed in claim 4 having four outlet pipes in communication with the interior of the chamber.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
US00365163A 1972-05-31 1973-05-30 Pumps Expired - Lifetime US3837762A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2542672 1972-05-31

Publications (1)

Publication Number Publication Date
US3837762A true US3837762A (en) 1974-09-24

Family

ID=10227476

Family Applications (1)

Application Number Title Priority Date Filing Date
US00365163A Expired - Lifetime US3837762A (en) 1972-05-31 1973-05-30 Pumps

Country Status (5)

Country Link
US (1) US3837762A (it)
DE (1) DE2327542A1 (it)
FR (1) FR2187034A5 (it)
IT (1) IT986393B (it)
NL (1) NL7307561A (it)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4147480A (en) * 1977-08-19 1979-04-03 Deutsch Daniel Harold Asymmetric permeable member
US4147481A (en) * 1977-08-19 1979-04-03 Deutsch Daniel Harold Asymmetric permeable member
WO1980001825A1 (en) * 1979-02-22 1980-09-04 D Deutsch Asymmetric permeable member
WO1980001824A1 (en) * 1979-02-22 1980-09-04 D Deutsch Asymmetric permeable member
US20090022586A1 (en) * 2007-07-18 2009-01-22 Honda Motor Co., Ltd. Axial diffuser for a centrifugal compressor

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2210401A (en) * 1936-06-09 1940-08-06 Mervin J Fulton Pumping mechanism
US2609141A (en) * 1944-10-02 1952-09-02 Sulzer Ag Centrifugal compressor
US2694296A (en) * 1951-10-15 1954-11-16 Int Harvester Co Flow restricting device
FR1373013A (fr) * 1963-03-20 1964-09-25 Electric Auto Lite Co Dispositif convertisseur pour systèmes générateurs de poussée
US3333762A (en) * 1966-11-16 1967-08-01 United Aircraft Canada Diffuser for centrifugal compressor

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2210401A (en) * 1936-06-09 1940-08-06 Mervin J Fulton Pumping mechanism
US2609141A (en) * 1944-10-02 1952-09-02 Sulzer Ag Centrifugal compressor
US2694296A (en) * 1951-10-15 1954-11-16 Int Harvester Co Flow restricting device
FR1373013A (fr) * 1963-03-20 1964-09-25 Electric Auto Lite Co Dispositif convertisseur pour systèmes générateurs de poussée
US3333762A (en) * 1966-11-16 1967-08-01 United Aircraft Canada Diffuser for centrifugal compressor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Byron Jackson Bulletin 37 5050, 1938 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4147480A (en) * 1977-08-19 1979-04-03 Deutsch Daniel Harold Asymmetric permeable member
US4147481A (en) * 1977-08-19 1979-04-03 Deutsch Daniel Harold Asymmetric permeable member
WO1980001825A1 (en) * 1979-02-22 1980-09-04 D Deutsch Asymmetric permeable member
WO1980001824A1 (en) * 1979-02-22 1980-09-04 D Deutsch Asymmetric permeable member
US20090022586A1 (en) * 2007-07-18 2009-01-22 Honda Motor Co., Ltd. Axial diffuser for a centrifugal compressor
US8038392B2 (en) * 2007-07-18 2011-10-18 Honda Motor Co., Ltd. Axial diffuser for a centrifugal compressor

Also Published As

Publication number Publication date
IT986393B (it) 1975-01-30
NL7307561A (it) 1973-12-04
FR2187034A5 (it) 1974-01-11
DE2327542A1 (de) 1973-12-13

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