EP0072636A2 - Pompes rotatives à fluide à N/N +1 lobes - Google Patents

Pompes rotatives à fluide à N/N +1 lobes Download PDF

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Publication number
EP0072636A2
EP0072636A2 EP82303950A EP82303950A EP0072636A2 EP 0072636 A2 EP0072636 A2 EP 0072636A2 EP 82303950 A EP82303950 A EP 82303950A EP 82303950 A EP82303950 A EP 82303950A EP 0072636 A2 EP0072636 A2 EP 0072636A2
Authority
EP
European Patent Office
Prior art keywords
clearance
pump
rotors
normal running
rotor
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.)
Withdrawn
Application number
EP82303950A
Other languages
German (de)
English (en)
Other versions
EP0072636A3 (fr
Inventor
Robin Edward Child
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.)
Concentric Pumps Ltd
Original Assignee
Concentric Pumps 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 Concentric Pumps Ltd filed Critical Concentric Pumps Ltd
Publication of EP0072636A2 publication Critical patent/EP0072636A2/fr
Publication of EP0072636A3 publication Critical patent/EP0072636A3/fr
Withdrawn legal-status Critical Current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
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2/00—Rotary-piston machines or pumps
    • F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C2/082—Details specially related to intermeshing engagement type machines or pumps
    • F04C2/084—Toothed wheels

Definitions

  • This invention relates to rotary fluid pumps of the N and N+1 lobed type disclosed in for example prior Patent No. 1032862.
  • the object of the present invention is to provide an improved practical form of pump of the type disclosed in Patent No. 1032862.
  • a pump of this type wherein clearance is provided at the roots of the outer rotor in excess of normal running clearance characterised in that the inner and outer rotors are conjugate (as defined herein) at at least one of the positions of full mesh whereby in the or each such position a substantially normal running clearance or clearances is maintained at the opposite side of the inner rotor axis to the position of full mesh.
  • normal running clearance refers to the separation that is present between the driving surfaces of the rotor forms during those parts of each rotor revolution wherein the rotors are not substantially fully meshed. In practice, while such surfaces will be in drive transmitting relation they will be separated by a film of the oil which is being pumped. Typically, as mentioned above, normal running clearances range up to about 0.0055 inch (about 0.014cm) depending upon pump size. Calculations for a prior art 6/7 lobed pump, indicate that normal running clearances will prevail for about 55% of the time and for the remaining 45% of the time, the clearances will become excessive. Thus, the present invention allows normal running clearances to be attained for the remaining 45% of the time with improved volumetric efficiency.
  • the present invention is based on the realisation that, contrary to previous thinking, volumetric efficiency is affected by providing for dirt clearance at the interlobe roots of the outer rotor despite transfer of the area of driving contact from one side to the other.
  • the deleterious affect is primarily attributable to two factors: firstly the relatively large dirt clearances at the interlobe roots of the outer rotor; and secondly the fact that in pumps of the type with which the present invention is concerned, the outer rotor does not rotate about a precisely fixed centre, the practice being to mount the outer rotor in a housing which permits a limited radial floating movement to compensate for tolerances in manufacture etc.
  • the present invention avoids this phenomenon by reducing the clearance between the registering lobe and root at that point where the outer rotor would otherwise be able to shift radially and create a leakage gap or gaps at the opposite side of the inner rotor axis.
  • each interlobe root of the outer rotor In the prior art for convenience of manufacture and for provision of dirt clearance, it is known to form the "base" of each interlobe root of the outer rotor as a part cylindrical surface but in the past the clearance gap between the inner rotor lobes and each root has always been in excess of normal running clearance even at the zone of closest approach between the two.
  • the inner and outer rotors are conjugate such that the clearance at this zone is limited to a value which ensures that the clearances on the opposite side of the inner rotor axis are substantially normal running clearances.
  • each of the interlobe roots 22 of the annulus 14 are formed as part cylindrical surfaces which afford dirt clearance pockets for passage of dirt particles through the pump.
  • the clearance at point 24 of each root 22 is greater than the normal running clearance allowed at other points around the peripheries of the rotor 10 and annulus 14. This has not been considered undesirable in the past as explained hereinbefore.
  • the inner rotor 10 is conjugate with the annulus 14 such that, in the illustrated embodiment having an inner rotor with an even number of lobes, the diametral distance between the tips of the inner rotor lobes is less than the distance from the point 24 (the zone of closest approach) and the annulus lobe tip 32 by an amount such that the clearances 24 and 32 are normal running clearances, i.e. no greater than 0.0055 inch (0.014cm).
  • Figure 4 serves to illustrate further the loss of pump efficiency that occurs with prior art pumps.
  • This Figure also shows, on a somewhat exagerrated scale, the radial clearance or play 40 provided between the outer rotor 14 and its housing 15.
  • Such clearance is necessary in practice to allow for the manufacturing tolerances involved in the production of the rotors 10,14.
  • the maximum. clearance between the outer rotor 14 and its housing 15 will in general exceed the normal running clearance between the rotors and will typically be of the order of 0.006 - 0.013 inch (0.015 - 0.033cm).
  • the same reference numerals are used in Figure 4 as in Figures 1-3 and it will be seen that the excessive dirt clearance at point 24 results in large separations (exceeding normal running clearances) at points 32 at the opposite side of the axis 16.
  • Figure 5 corresponds to Figure 4 but illustrates the improvement that results when the clearance that can occur at point 24 is reduced.
  • the clearances at points 32 can be constrained to normal running clearances thereby providing effective sealing between the rotors and avoiding loss of pump efficiency.
  • the improvement provided by the present invention also leads to smoother running of the outer rotor since its freedom to float radially is constrained to a greater extent in each position of full mesh.
  • the improved sealing obtained with pumps in accordance with the invention is particularly noticeable with inner rotors having an even number of lobes and while the effect is not as significant, in terms of volumetric efficiency, for odd lobed inner rotors, the fact that the outer rotor is constrained to a greater extent by the inner rotor results in improved pump operation.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Rotary Pumps (AREA)
EP82303950A 1981-08-15 1982-07-27 Pompes rotatives à fluide à N/N +1 lobes Withdrawn EP0072636A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8124995 1981-08-15
GB08124995A GB2104153B (en) 1981-08-15 1981-08-15 Rotary positive-displacement fluid-pumps

Publications (2)

Publication Number Publication Date
EP0072636A2 true EP0072636A2 (fr) 1983-02-23
EP0072636A3 EP0072636A3 (fr) 1983-03-09

Family

ID=10523975

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82303950A Withdrawn EP0072636A3 (fr) 1981-08-15 1982-07-27 Pompes rotatives à fluide à N/N +1 lobes

Country Status (3)

Country Link
EP (1) EP0072636A3 (fr)
ES (1) ES514979A0 (fr)
GB (1) GB2104153B (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0173778A1 (fr) * 1984-09-05 1986-03-12 Hobourn Engineering Limited Pompes
EP0218806A1 (fr) * 1985-08-31 1987-04-22 Wankel, Felix, Dr. h.c. Machine à piston à axe interne
WO2004038223A1 (fr) * 2002-10-22 2004-05-06 Concentric Pumps Limited Amelioration relative aux pompes

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2022841B3 (es) * 1986-07-19 1991-12-16 Barmag Barmer Maschf Bomba de rueda dentada interior.

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3126833A (en) * 1964-03-31 Figures
US1682563A (en) * 1921-11-05 1928-08-28 Myron F Hill Internal rotor
US1486836A (en) * 1923-04-28 1924-03-11 Hill Compressor & Pump Company Rotary-pump pressure control
US2031888A (en) * 1928-08-24 1936-02-25 Hill Engineering Company Inc Tooth curve for rotors and gears
GB958779A (en) * 1960-05-19 1964-05-27 Robert Wesley Brundage Improvements in gear type hydraulic pumps and motors
US3273502A (en) * 1964-02-24 1966-09-20 Stewart Warner Corp Pumping and metering device
DE1525066A1 (de) * 1965-01-15 1969-07-03 Otto Eckerle Verfahren zur Herstellung eines Rotors,insbesondere fuer Innenlaeuferzahnradpumpen
GB1233376A (fr) * 1967-11-17 1971-05-26
US3536426A (en) * 1968-04-03 1970-10-27 Novelty Tool Co Inc Gear pump having eccentrically arranged internal and external gears
US3824047A (en) * 1973-03-23 1974-07-16 Dermott H Mc Floating rotary ring member of fluid displacement device
DD106219A1 (fr) * 1973-06-20 1974-06-05
IT1118556B (it) * 1979-04-12 1986-03-03 Whitehead Moto Fides Spa Stabi Procedimento per la realizzazione di una pompa meccanica rotativa e relativa pompa ottenuta

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0173778A1 (fr) * 1984-09-05 1986-03-12 Hobourn Engineering Limited Pompes
EP0218806A1 (fr) * 1985-08-31 1987-04-22 Wankel, Felix, Dr. h.c. Machine à piston à axe interne
WO2004038223A1 (fr) * 2002-10-22 2004-05-06 Concentric Pumps Limited Amelioration relative aux pompes

Also Published As

Publication number Publication date
ES8400180A1 (es) 1983-10-16
ES514979A0 (es) 1983-10-16
GB2104153B (en) 1984-08-30
EP0072636A3 (fr) 1983-03-09
GB2104153A (en) 1983-03-02

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19830610

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Effective date: 19840522

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Inventor name: CHILD, ROBIN EDWARD