US3031974A - Self-priming gas-expelling pump - Google Patents

Description

May 1, 1962 M. EDWARDS 3,031,974

sELF-PRIMING GAS-EXPELLING PUMP Filed March 8, 1955 5 Sheets-Sheet 1 INVENTOR.

M I LES LOWELL EDWARDS ATTORNE S May 1, 1962 M. L. EDWARDS SELF-PRIMING GAS-EXPELLING PUMP 3 Sheets-Sheet 2 Filed March 8, 1955 INVENTOR.

MILES LOWE LL EDWARDS K@ f A oRNEYs May 1, 1962 M. l.. EDWARDS 3,031,974

SELF-PRIMING GAS-EXPELLING PUMP Filed March 8, 1955 l 5 Sheets-Sheet 3 INVENTOR.

MILES LOWELL EDWARDS ATTORN S United States Patent O 3,031,974 .SELF-PRIMING GASfEXPELLING PUMP Miles LowellgEdwards1092 SW. Westwood Drive,v Portland, Oreg, Filed Mar. 8, 1955, Ser. No. 492,913` 5 Claims. (Cl. 103-113) This invention relates to an improved self-priming gasexpelling liquid pump, and has particular reference to a booster pump in an aircraft fuel system.

The attitudes assumed by an airplane in flight and the conditionsY of flight impose certain requirements on the booster pump which is mounted on or in each fuel tank for the purpose of delivering liquid fuel to the engine fuel pump or toanother tank. In certain maneuvers, the normal force of gravity or centrifugal force acting in conjunction withgravity causes the fuel to move to different positions in the tank which may carry the fuel temporarily away from the inlet to the booster pump causing the conventional booster pump to become gasbound and incapable of pumping liquid when the inlet is again submerged. For example, during acceleration at` the starrt of a dive andduring the progress of asteep climb, thefuel moves to the rear end of'the tank, whereas, ata later interval in a diving maneuver, the fuel falls by gravity to the forward' end of the tank. A common location for the booster pump is a mounting in a vertical bulkhead on a side of the tank where the pump is a short distance above the tank iloor. The suction pipe for the pump projects through the tank side Wall and down substantially to the tank oor. In such maneuversthe pump inlet in` the bottom of the tank mayy not be submerged andthe pump will'draw in air causing it to lose its prime. `Conventional booster pumps have heretofore been equipped'with various means to repel or separate vapor and gas from the pumped liquid, but such means are inadequate for self-priming purposes under the conditions described.

It is, therefore, the general object of the present invention to provide an improved self-priming gas-expelling liquid pump which will not bey rendered gas-bound and inoperative by the admission of large quantities of gas.

Another object is to provide a pump of the type described which will satisfy the requirements of an aircraft booster pump under the3 extremel conditions of'ight hereinabove' mentioned, and whichv will overcome thel shortcomings and disadvantages of conventional booster pumps.

Another object is to provide a novel and-improved' combination and arrangement of a displacement type` of gas` The'y present: pump. comprises; twopumping units, one

beinga centrifugal type liquid pump andithe other being a hydroturbinek or'liquid ring type of' displacement gas pump. T hetwo. pumping unitsfare arranged one behind the other and have separate impellers mounted on a common shaft. has anewy andv improved bladeshape wherein the inner ends and leading edges ofthe'blades forma screw typev impellen and the outer ends` and'4 trailing edgesl of the same blades. function asacentrifugal typeimpeller. Gas removalf openings. are provided between the blades to communicate.,v with a suction chamberv between thetwo pumping units. The` hydroturbine pumpingV unitV draws The impeller of the centrifugal pump rice gas and'vapor continuously from the suction chamber and' stood with reference to the following description ofthe i preferred embodiment illustrated on the accompanying drawings. It is to be understood, however, that the invention is not' limited to an aircraft booster pump and that' all changes inthe construction and' arrangement of parts within the scope of the appended claims are included in the invention.

lln` the drawings:

FIGURE lis a longitudinal sectional View of an aircraft booster pump embodying the principles of the invention;

FIGURE 2 is a frontelevation view of thecentiifugal impeller shown in FIGURE 1;

FIGURE 3 is a rear elevation view ofthe centrifugal impeller; l

FIGURE 4.is a cross sectional View taken on the line 4-4 of FIGURE 1;

FIGURES is a cross sectional view taken on the line 5-5of FIGURE 1 showing the suction ports of thehydroturbine pump;

FIGURE 6 is a cross sectional view taken on the line 6-6 of FIGURE l showing the discharge ports of the hydroturbine pump;

FIGURE 7 is alongitudinal sectional view of the hydroturbine pump unit taken on the line 7-7 of FIG- URE 1; y

FIGURE 8 is a perspective view of the inner housing member of the hydroturbine pump unit;

FIGURE 9 is a perspective view of the impeller or rotor of the hydroturbine pump unit;

FIGURE l0 is a cross sectional view taken on4 the line FIGURE ll is a fragmentaryside elevation View with partsV in section of the structure shownin FIGURE l0; and:

FIGURE l2 is a fragmentary sectional View showing an aircraftA wing tank with the present booster pump mounted in a vertical side wall thereof.

General Description The pump assemblage in FIGURE 1 comprises a centrifugal liquid pumping unit A and a displacement' type gas pumpingunit B. These two pump units are connected together in end to endrelation on one end of a motor iti, and the whole pump assemblage', comprising units A and B and motor lill and designated P inFlG- URE l2, is secured to a mounting plate l1 by means of screws 12; Plate l-l'of FIGURE l is fastened in an opening in the wall 8 of a fuel tank 9 (FIGURE 2) by means of screws 13 and mounting ring 14 (FIGURE 1)'. Thisl joint is sealed by a gasket 15. An inlet' pipe 16 for the pump unit Aprojects through plate l1 and into the tank 9.

Inlet pipe 1 6 is preferably'equipped with a curved pipe extension or hose i60.' (FIGURE l2) extending down close to thel bottom portion of the tank. Thus, air is drawn into the pipe 16 when the body of fuel at a'low level L moves away from the wall 8 as indicated at- L" so that the inlet end of pipe Ida is not submerged. The function ofthe gas pump unitB (FIGURE 1)- isr to remove such air from'the centrifugal pump A (FIGUREI) and preventits becoming gas-bound, and also to remove vapor and gas from the pump A which may be evolved by the beating of the impeller blades of pump A against the liquid and also gas and vapor evolved from a reduction of atmospheric pressure on the surface of the fuel as the airplane reaches a high altitude.

Mounted on the rear end of inlet pipe 16 is a casting 17 forming a volute chamber 20 and a flanged discharge outlet 21 adapted to be connected to a fuel delivery pipe. Connected on the rear side of volute casting 17 is a circular casting 22 having wall portions defining a suction chamber lbetween the pump units A and B. Mounted on the rear of suction chamber casting 22 is another circular casting 23 having inner walls enclosing a portion of the gas pumping unit B and outer walls enclosing and defining a reservoir chamber, the last mentioned walls terminating in a circular flange 24 on which the housing 25 of motor 10 is mounted by means of screws 26. The various joints between the aforementioned parts are sealed with suitable gaskets. Projecting through these castings from the motor lil is a drive shaft 27. A centrifugal pump impeller Sil is mounted on the end of shaft 27 in pumping relation with the volute chamber 20, and a hydroturbine pump impeller 3-1 is mounted on the shaft within the gas pump housing formed by the inner Walls of the casting 23. Both impellers are rigidly secured to the motor shaft 27.

Centrifugal Pumping Unit The inner end of inlet pipe 16 has an expanding throat defined by a curved wall surface 35 leading into a pumping chamber and volute chamber 20. The pumping chamber containing impeller is closed on its rear side by a transverse radial wall 36 on the casting 22. This wall contains a cylindrical flange portion 37 spaced slightly from the hub 38 of the impeller to provide a restricted annular gas passage and port 40. The annular passage 40 establishes communication between a suction chamber 41 and the pumping chamber associated with impeller 30. Flange 37 projects well into chamber 41 for a purpose presently to be described.

The impeller hub 38 carries a plurality of blades 42. The blades 42 have leading ends 43 radiating outwardly and forwardly from the hub 38 to form a screw type impeller with relatively sharp leading edges 44 which are adapted to slice into the approaching column of liquid in the manner of auger blades and produce axial flow of the liquid entering the impeller. The leading ends 43 project forward into the expanding throat of inlet pipe 16 and the forward and peripheral edges 45 are shaped to provide a close running lit with the ilared surface 35, thereby forming an open or unshrouded type of impeller.

Each blade continues through an arcuate extent of approximately 180 degrees in compound curvature to a trailing end 46 which is substantially reduced in an axial direction to correspond to the width of volute chamber 20. The `blade surface at the trailing end 46 is approximately parallel with the axis of rotation. Thus each blade gradually changes shape in compound curvature from an inner leading end having predominantly screw action and relatively little or no centrifugal pumping action to a trailing end having only centrifugal pumping action and substantially no screw action. The axial flow leading ends sweep a large circle of revolution, as shown in FIGURE 3, and are effective at high speed for pumping gas and liquid mixtures, the gas being removed and the liquid thereafter being subjected to centrifugal pumping action lin its further progress through the impeller.

There is no continuous back plate on the impeller, but instead each `blade is connected with a transverse radial flange portion 56 of crescent shape, leaving wide spiral slot openings therebetween as shown in FIGURE 3. The inner ends of the crescent flanges 5t) all connect with hub 3S and also with rearwardly exten-ding circular flange S1 which rotates in a close running fit within a similarly shaped recess in the wall 36. Gas port openings 52 between the blades and inwardly of the flange 51 communicate with the annular passage and port 40 leading to the suction chamber 41. The openings 52 are located close to the axis of the impeller where the approaching liquid is in a region subject to screw impeller action and before the liquid has progressed to the outer regions of the pumping chamber where it is subject to centrifugal impeller action. Thus the screw shaped inner ends 43 of the blades tend to propel any liquid and gaseous mixture entering the yeye of the impeller first in an axial direction which tends to crowd entrained gases and vapors axially through the openings 52, and this movement is assisted by suction from the annular passage 40. By the time such a liquid and gaseous mixture reaches the rear flange walls Sil the heavier gas-free liquid is subjected to an increasing extent to the centrifugal pumping action of the intermediate portions of the blades, while the lighter gaseous and vapor components tend to -be displaced inwardly toward the axis of rotation, as well as rearwardly toward the openings 52.

It will be appreciated by persons skilled in the art that booster pumps associated with the fuel tanks of fast climbing and high flying airplanes tend to liberate gas and vapor from the fuel by the beating action of the pump impeller blades against the liquid, in addition to vapor and gas that may be liberated in the tank itself and drawn into the inlet pipe. Hence, the problem of preventing the booster pump from becoming vapor locked is present in such aircraft, in addition to the problem of re-priming the pump after large quantities of air are drawn into the inlet pipe by reason of movement of the fuel away from the pump inlet. In the present pump, the novel shape of the blades 42, whereby they rirst exert a screw impeller action on the entering liquid and thereafter a centrifugal pumping action, is effective to prevent a gas-bound condition resulting from the evolution of vapor and gas within the body of the fuel itself, while the action of the displacement gas pump B in maintaining a suction condition in the suction chamber 41 enhances this action and also operates continuously to prime the centrifugal pumping unit A to re-start the liquid iiow after large quantities of air have entered the intake pipe by reason of the movement of the fuel in the tank.

Hydroturbz'ne Pumping Unit The casting 213 is shaped to form an outer or peripheral wall 60 and a transverse radial rear wall 61 around the hydroturbine pump impeller 31. These walls constitute what may be referred to as an outer housing for the hydroturhine pump having an upper chamber space 62 and a lower chamber space 63, these chambers being defined by eccentric cavities or lobes in the casting 23 as shown in FIGURES 5 and 6. This pump also has an inner housing and port member integral with affront plate 64, as shown in FIGURE 8, which is secured to the casting 23.

An upper intake port 65, just above the shaft 27, communicates with the interior of impeller 3-1 opposite the upper chamber 62, and a lower intake port 66 just below the shaft 27 communicates with the interior of the impeller opposite the lower chamber 63. The lower intake port 66 is connected with a vertical passage 67 in the plate 64 having an open lower end 68 in a sump 69 in the bottom of suction chamber 41. Upper port 65 is connected with a generally horizontal passage 65a having an open end at one side of suction chamber 41. The two chambers 62 and 63 produce local radial pulsations in a revolving liquid ring which forms two separate and independent vacuum pumps within the impeller whereby the intake of liquid through port 66 is not affected by the intake of gas or vapor through the port 65. As long as there is any liquid present at opening 68 the port 66 will continue to remove such liquid while the port 65 may contmue to remove gas. Passage 65a also withdraws liquid whenever its open end is submerged.

The 90'degreerelationship ofpassages 65a and67 permitsthe pump assembly P to berotated 90 degrees in one direction to'provide an-alternate mounting position with passage 65a turned to-sump position if desired. When so mounted; the intakeof gas or vapor through port 67 does not impair thepumping ofiliquid from sump 69.

The inner housingand port member of the hydroturbine pump comprises. inclinedfdivergent walls 70 and vertical side walls-71'- on-a generally cylindrical protuberance projecting within the impeller 31` to limit communication of intake port 65to the upper side of the impeller opposite chamber 62, and similarly. limit the communication of intakeport 66 to the lower sideof the impeller opposite chamber 63. The-walls 70'merge intoV cylindrical portions-'741 which are interruptedv on opposite sides of the pump, as shown in FIGURES'7 and 8, to provide'outlet ports 72 leading to a common central discharge chamber 73 surroundingv the: shaft 27.

The impeller rotor 31 comprises a plurality of blades 75 having substantially'atradial inner portions and forwardly curved outer. edges relative to the direction of rotation. These: blades are integrally joined at their ends with` front and rear radial flange plates 76' and 77. Projecting: rearwardlyV from the end flange 77 is a circular ange 78 spaced outwardly from the impeller hub 79 which-is mounted'v on the motor shaft 27. A plurality of short propeller blades80 form spokes between the hub 79 and ange 78 for supporting the impeller on the hub. Inner cylindrical flanges 82 have a close running lit around cylindrical surfaces 74 of the port member. The blades Sil are turned in a direction` for pumping liquid back into the hydroturbine pump from a reservoir chamber 85 in counter flow relationto gas being discharged from the hydroturbine pump through openings 81 between the blades, whichY action will presently be-described in detail.

A discharge pipe-S6 has an open end at approximately the mid level of chamber 85 adjacent the rear. wall 87. Tvapor and gas and excess liquid discharged from the hydroturbine pump escape from reservoir 85 by way of pipe 86 which communicates with the interior of the fuel tank at aipoint removed from the intake end of pipe 16a so thatv such gas and vapor are not drawn backy into the centrifugal pump. Pipe 86 has a return bend leading upwardly and forwardly toward the tank 9.

Operation A hydroturbine pump is a displacement type of gas pump wherein a revolvingring of liquid follows an eccentric peripheral wall and is thereby subjected to local radial pulsations to produce a pumping action. With reference to FIGURES, it`will be understood that a ring of liquid revolving with the impeller blades 7'5 in the indicated direction will always be moving outwardlyaway from the intake ports SST-ind" 66 asthe liquid approaches the deepening cavities 62" and 63. Thus' a constant suction effect is producedirr the ports65 and 66 and the pumping action' in port 65', by're'ason'of cavity 62, is independent ofthe'pumping actionV in yport 66 by-reason of cavity 63.

As the liquid rin'gisforced inV between the blades 75 toward' the axis `ofrotatiorr upon leaving the deep portions ofthe cavities 62and-6'3^,- gasand excess liquid being carried between the bladesy arey expelled through the discharge ports 72; into the commonv discharge chamber 73 as shown in FIGURE 6. VaporY and gas are readily discharged through the openings-81 between the counterflow propeller blades 86, and excess liquid is forced through these openings, but liquid tends to bereturned by propeller 80 in suicient quantityV to maintainv the' liquid ring which is necessary for operation of a hydroturbine pump. All parts of the impeller 31 have a close running lit with the inner and outer housing members of the hydroturbine pump.

When pump units are operating, the propeller blades 8) maintain a whirling pool of liquid in reservoir 35 rotating approximately concentric with shaft 27. Cenbe apparent thatadditional liquidentering reservoir 85VK will increase theradial depth of the whirlingpool causing` liquid to be discharged through pipe 86 along with the gas. A portion of! the liquid ring" in reservoir 85 is inv constant engagement with the propeller b-lades d0, which engagement keeps the ring revolving and also returnsl some of the liquid `from reservoir 85' back into the hydrotunbine pump as may be requiredto maintain its, liquid ring. Such liquid passes: through propeller Sil in a thin stream within the flange 78A in a counter flow.l surround-1 ing the escaping gas whereby the liquid and gas may flow` simultameously in opposite directions through the pro-v peller whenever the f quantity oflliquid in the hydroturbine pump is diminished. Thus, the liquid ring in the hydroturbine pump and the whirling: liquid pool inreservoir are maintained` in all attitudesof flight while the pump is operating, and even during intervals when the liquid in the tank has moved away from intake pipe 16a, as shown at' L in FlGURElZ, and the pump units are drawing air.

When the pump is not operating, all the pump chambers and reservoirs are ooded in normal ight attitudes, if there is` sufficient depth of liquid` inthe tank'. -I'f the liquid in the tank is at a low level and. should move tov v' sumes a vertical positionwith the motor uppermost, a

sucient quantity of liquid will be retained in suction chamber 41 byy reason of the length of flange 37 which extends almost to plate 64. Flanges 82 retain sufficient liquid in the hydroturbine pump itself to start a pumping action ywhichfwiil fully restore the liquid ring in the hydro-- turbine pump from the liquid in suction chamber 41 as soon as such liquid returns tothe sump 69; in case the pump is started during such `a maneuver. down position, all the liquid cannot escape from either f suction chamber `#t1 or reservoir 85.

Under conditions when gas and vapor are evolved. in or drawn into the pump A, such gas is forced into a ringA of small diameter in the region of ports 52 bycentripetal action. The gas-free liquid forms a surrounding ring crowding the gas and vapor radially inwardly as the liquid is being discharged from the volute housingthrough. the discharge connection 21. Such gas and vapor in the region of ports 52 are removed bythe suction of the hydroturbine pump and discharged into reservoir chamber 8S- in the manner described.

From the foregoing description it-will beA apparent how the present booster pump assemblyV functions to deliver any adequate supply of fuel, regardlessA of the vattitude cr condition of flight or the level of the fuely supply ine the tank. In all possible positions of the pump, an adequate supply of liquid' is held availablel to the hydrotur-bine pump unit to reestablish its liquid ring afterl thepump has been shut off, whereby it possesses a self-priming characteristic which will restore a normal flow' of gasA free" liquid fuel as soon as the intake pipe becomes submerged. Having now described' my invention and in what manner the same may be used, what I claimv yas new and desire to protect byV Letters Patent is:

1. A self-priming, gas-expelling purnpcomprisingcasing means defining an axial pump inlet at one end, an axial gas outlet at the other end, an impeller chamber therebetween land a peripheral pumping chamber surrounding the impeller chamber, an impeller in the impeller chamber having blades with screw-shaped leading ends spanning said inlet to induce axial ow and upstand- In an upsideing trailing ends substantially parallel with the impeller axis to induce centrifugal discharge into the pumping chamber, said axial gas outlet communicating with the impeller chamber at a zone where fluid therein is subject to the axial flow inducing force of the screw-shaped vane portions and has not yet been substantially subjected to the centrifugal discharge force of the upstanding trailing ends of the blades, said impeller being provided with gas removal openings close to the axis of blade rotation and in communication lwith the gas outlet receiving and directing entrained gases from the liquid body in the pumping chamber to prevent vapor locks, a gas pump -for receiving uid fro-m said gas outlet effective to prevent said impeller from 'becoming gas-bound to maintain its centrifugal pumping force, an outlet for said gas pump, and a counterow impeller in said outlet for returning liquid to the gas pump.

2. A self-priming, gas-expelling pump assembly comprising a pump casing having an axial inlet, an impeller chamber adjacent said inlet, a centrifugal pumping chamber surrounding the impeller chamber, a peripheral outi let for said pumping chamber, and a gas outlet radially inward from the pumping chamber, an impeller in said impeller chamber having a plurality of pumping vanes with axial flow inducing portions and centrifugal pumping portions, said axial flow inducing portions of said blades being eective to iiow gases from the impeller chamber to the gas outlet, said centrifugal pumping portions being effective to propel liquids from the impeller chamber into the pumping chamber, said impeller being provided with gas removal openings close to the axis of blade rotation and in communication with the gas outlet receiving and directing entrained gases from the liquid body in the pumping chamber to prevent vapor locks, a hydroturbine pump, casing means providing a suction chamber receiving uids from the gas outlet, inlet means connecting the suction chamber with the inlet of the hydroturbine pump, casing means defining a reservoir chamber receiving fluid from the hydroturbine pump, an impeller for centrifugally separating gases and liquids in said reservoir chamber and for maintaining liquid in the hydroturbine pump, and a gas and excess liquid outlet for said reservoir chamber.

Y 3. A pump assembly, comprising first casing means defining an axial pump inlet, an axial gas outlet, and a volute pumping chamber in communication with said pump inlet; an impeller in pumping relation with the volute chamber comprising a rotatable member having blades suspended therefrom with screw-shaped leading ends spanning said inlet to induce axial flow and upstanding trailing ends substantially parallel with the impeiler yaxis to induce centrifugal discharge into the volute pumping chamber, said axial gas outlet being formed in Isaid rotatable member centrally of said blades and discharging into a sump chamber, said axial gas outlet communieating with said pumping chamber close to the impeller axis where fluid is subject to the axial flow inducing force of the screw-Shaped vane portions and has not yet been substantially subjected to the centrifugal discharge force of the upstanding trailing ends of the blades; second casing means connected to said first casing means; said sump chamber being formed between said rst and second casing means, a hydroturbine gas pump in said second casing means having first and second pumping chambers receiving fiuid from said sump chamber through first and second radial and axial passageways, respectively, and effective to prevent said impeller from becoming gas bound to maintain its centrifugal pumping force; and an outlet for said gas pump.

4. A pump assembly, comprising rst casing means defining an axial pump inlet, an axial gas outlet, and a volute pumping chamber intermediate said inlet and said outlet; an impeller in pumping relation with the volute chamber having blades with first portions shaped to induce axial flow and second portions shaped to induce centrifugal discharge into the pumping chamber, said axial gas outlet communicating with said pumping chamber close to the impeller axis where iuid is subject to the axial iiow inducing force of the first Vane portions and has not yet been substantially subjected to the centrifugal discharge force of the second portions of the blades; second casing means connected to said first casing means; a gas pump in said second casing means receiving fluid from said gas outlet and effective to prevent said impeller from becoming gas bound to maintain its centrifugal pumping force; an outlet for said gas pump; and a counterliow impeller in said outlet for returning liquid to said gas pump.

5. A pump assembly, comprising a first housing having an inlet` and defining a centrifugal pumping chamber, a

` peripheral liquid outlet for said pumping chamber, and

a gas outlet radially inwardly of said pumping chamber;

an impeller in pumping relation with said pumping chamber comprising a rotatable member having a plurality of vanes suspended therefrom with screw-shaped axial liow inducing portions 'and centrifugal pumping portions, said gas outlet being formed in said rotatable member axially and centrally of said varies, said axial flow inducing portions iiowing gases from said pumping chamber to said gas outlet and said centrifugal pumping portions propelling liquid into said pimiping chamber, said gas outlet communicating with said pumping chamber close to the impeller axis where lfluid is subject to the action of said axial flow inducing portions and has not yet been substantially subjected to said centrifugal pumping portions; a second housing connected to said first housing; a hydroturbine pump in said second housing having first and second pumping chambers; means delining a suction chamber between said first and second housings having a sump portion yadapted to retain uids and receiving fluids from said gas outlet; means defining separate first and second communicating radial and `axial flow passages connecting said sump portion with said first and second pumping chambers, respectively, of said hydroturbine pump; and a discharge for said hydroturbine pump.

References Cited in the file of this patent UNITED STATES PATENTS 2,134,686 De Lancey Nov. 1, 1938 2,368,528 Edwards Jan. 30, 1945 2,416,538 Nelson Feb. 25, 1947 2,427,716 Curtis Sept. 23, 1947 2,500,228 Adams Mar. 14, 1950 2,581,828 Adams Jan. 8, 1952 2,693,148 Doelter Nov. 2, 1954 2,704,516 Mock et al. Mar. 22, 1955 2,736,266 Eisele Feb. 28, 1956 2,780,176 Holzwarth Feb. 5, 1957 2,804,022 Adams Aug. 27, 1957 2,811,110 Edwards Oct. 29, 1957 2,832,292 Edwards Apr. 29, 1958 2,845,871 Compton Aug. 5, 1958 2,850,984 Shiley Sept. 9, 1958 FOREEGN PATENTS 654,854 Great Britain July 4, 1951 686,102 Great Britain Jan. 21, 1953

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