US2545626A - Spiral gear pump and allied device - Google Patents

Description

March 20, 1951 R. J. L. MOINEAU SPIRAL GEAR PUMP AND ALLIED DEVICE 2 Sheets-Sheet 1 Filed Oct. 2, 1947 lill,

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ATTORNEYS.

March 20, 1951 R. J. l.. MOINEAU SPIRAL GEAR PUMP AND ALLIED DEVICE 2 Sheets-Sheet 2 Filed Oct. 2, 1947 IN VEN TOR.

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ATTORNEYS.

Patented Mar.` 20, -1951 y UNITED ES lGFF 4split-.ptGffEea;rUMP ANDALMEDDEVIQE Ren JosephfLouis v-MoineaxnY Paris,:France;: Adele 'Mnineaun ad!'ninisa'atrix-lof lsaid Ren Joseph.

of Ohio Application'October 2, 1947,:SerialfNo. r777,431 n In France December 17; 1946 The presentiinyentionhas :forffits cbjecttogpro- .vide e an improvement in gear 1-type .machines .(pumpaenginesfr compressors) in Whichfthe gears comprise ytwo spiral .f elements Y,inside one another, the :outer elementzhaying one. spiral c,

:thread .or tooth kmore than the inner Y element,

4each `thread or. too-th .of .which :is constantly vin `contact in.V each .transverse :section with; the l.Out- .er.-element, thefpitchesgof `the threads, which -verse fcrossfsection v:in the ratio of fthe :numbers .of teeth.

.cated onfthetcorrespondingfaxis of said stator or `rotor respectively, the twolpointsof :articulation 'being separate; softhat theaes of Ythe -sta-torand of the lrotor move .in` pathsadescribingcones',.while saidaxes remain-parallel to each-other. A greater -simplicity .of yconstruction .thus obtained, .together fwithf.` advantageous :possibilities ofV Sbalarming.

Ifhave in thedrawings lshown several forms ofwstructure applying my* invention-to theaex.- ample of Aa pump, Alout fit Lwill he understood-that this is exemplaryonly .of-the invention as 'set forth in the appended claims. In-its essencefthe device tope described vmay be-usedv to -set upa ii'owin amobilesubstance, or by injectingmsuch ka `substance fin-t the device, the rotor k,member maybecaused t0 move-thus providing an engine .QI Compressor. Y

Figure 1 is a longitudial section .o fwapninpac- .cording t0 the invention in y.which the articulations of the stator androtor are vresrnectiyely `locatedat theiropposteends andhoth within the pumpcasing.

Figure 2 is -a...diag1am VA,showingthe v`,th eoretical relationships established.

Fig-,ure isa longitudinal section showing a modification ...of the-puI-npoffligure -1,l which is related to the diagramcoof Figure 2 in verticalr alignment, and in which-.Athe point of articulaform of the invention as Vapplied to a pump in Claims. (01.'1031117) l1-finer te rerersed andthefotor :driven ie @naar Lmaytbe constant or.-not,z.being -for each :transf 1.0 v

2. wenn the. point of zaetcnlat-on ef. the -,-rptgr the center of the pump bearing.

fE-fienre e5 fis :a f diagram fel-.lowing #one .determina-- tion @if-the resultant centrifugal forceren@ its Emoment. annffi-n an `.element moving as @1o-.tht .rotor and `stato-r .according t0. 'this Fienrei is .a iagam Showing mann .achieving .a balancing Pf PQI-0F and stator,- V A.

I nFignre 1 YVthe fp mfp.isshQWr1-wtpaeeasipg .direc/tion. The maarl working ,et materia iniudeitls page@ laeey theintake head, by

faxis describes a cone.

The ,-rotor.isshown at r9 having aspiral thread Vthuereon;thepitch of `tvhicharecords to y,ci-pleaber@arinounl 1 .t0-Wit: athis pas@ al that of the pitch .pf .the statin',Mittens- :The rotatie wanted by e bond-@d rubberfioipt its operating 4Shaft .il This .resnlts irl-the having a point of articulation at B and iwhiehritsaxis-describestetona-reversed l end, asgtotheffree path of the stator anis.

T11@A shaft U is held in eembination AS, 1s.2av.e bearing .-andfpaking vdevice termine a :par .the pump .casina t3 ipdiates a .jointfhetween fthe pump Shaft H C ter Shaft 2M, -whzih ltransmits the pump en@ thrusts to thefbearinesof thamptpr a |15- of metal or other rigid material. vflange of this stator by bolts 29 is a flexible 'the rotor at B.

drive. In this case the rotor shaft I1 lies in a cylindrical space I3 within a tube i9, which tube is positioned in the pump casing by suitable bearings 2i and 22. Bearing 22 receives all thrusts while bearing 2l serves strictly in a radial duty.` Stuffing box 25 contains suitable packing for the tube I9 with respect to the pump casing so as to make a leak-proof joint.

Bearings 2i and 22 are retained in an armlike body casting 23. The rotor shaft i7 passes through a flexible packing member 2G which is of resilient, rubber-like material and effects a liquid-tight joint and gives the shaft freedom for angular movement within the tube. The thrust from the rotor shaft is transmitted entirely through the packing member 20 to the tube i9 and thus to the bearing 22. The drive 54a for the rotor shaft is connected thereto by a universal joint connection Ilia. In this construction the apex of the cone within which the Vrotor can move will be at B, as the point of articulation.

In Figure Li the stator 5b is indicated as made Bolted to a membrane-like disc 6b, corresponding to flanges 6 of the other forms. This flange is held in place by the intake head 4b secured by bolts 8b to the pump casing. In this case the pump cas- Aing again has an arm-like extension 24a Within 'tilt therein as shown. The drive for the rotor shaft is a bonded rubber coupling 3l). The entrance of the rotor shaft into the pump cas- 'ing is through a flexible sleeve 28, within which is mounted a rigid stuffing box member 2 which contains suitable packing for the rotor shaft Ha. The result of this structure is to provide an articulation point for the stator at A and for In the second and third modifications, the articulation point for the rotor is in each instance outside of t-he pump casing, whereas in Figure 1 it is on the inside.

' vIn all of these forms, during the rotation of the rotor inside the stator, the stator can oscillate about the center A of the fiange and the rotor oscillates about the center B. These two points in the examples illustrated, are located at the opposite ends f the stator and of the rotor respectively. The relative movement of the stator and of the rotor can take place because in the :positions in which the rotor cannot move, the stator is free to move, and in the positions in which the stator cannot move, the rot-or can -meshing with a gear elementwith two teeth (stator the theoretical cross-section of the meshing gears.. at A is represented by the two pitch circles `C and D whose centers are A and E. The

vdiameters of lsaid'circles are in the ratio of 2 to l,

and the distance AE is equal to the eccentricity. It will be seen that when the circle D rolls without sliding in the circle C, the axis BE moves in a path describing a cone whose apex is at B and whose altitude is AB. If another section of the stator is considered in the same manner, the pitch circles C and D will beobtained Whose centers at A and E', and it will be seen that the axis AA of the stator describes a cone whose apex is at A and whose altitude is AB. These two cones have the same half-angle at the apex z. It would be possible to draw other cross-sections on one side or on the other of the ange 6, as for example the cross-section C and D", and the cross-sections would always be found to be in alignment in these conical movements.

The device described therefore definitely enables the rotor to roll correctly in the stator despite the fact that the stator and the rotor are supported respectively at one end only owing to the fact that the two points of articulation are separate.

It will be shown that by suitable choice of characteristics of this machine it can be perfectly balanced dynamically.

The sum Fr of the centrifugal forces applied to the rotor can be considered as being produced by a single mass applied to a point a located at a distance from the axis AB and equal to: Fr=mw, w beingthe angular velocity of the axis of the cone. Similarly, for the stator 5 the sums Fs of the centrifugal forces applied at b located at a distance y from the axis AB will, owing to the mass M of the stator be: VIPs- .ll/[wy The sums Fs and Fr of the centrifugal forces are always in the same plane, Vthat of the two axes EE and AA', and oppositely directed. For the machine to be balanced, it is necessary and sufcient that the two sums of forces shall be in alignment with one another and that: mwr=Mwy, or mx=My- The Velocity w is not involved. The calculation therefore shows and experiment confirms that the machine according to Figure 3 is perfectly balanced with a rubber stator and a rotor, for example, of plastic material or ebonite, the sole condition being that the foregoing equation mat=My is satisfied.

In my Patent No. 1,892,217 I have described families of arrangements of relative spiral threads, and the theory of the pump of which the present invention is a particular type. The flexible mountings with resultant conical paths may -be applied Wherever in any ofthe arrangements of vthe patentV there is, as a result of driving one -of the pump elements in a rotary manner, a

necessity for the other element to move in an orbit. In the present construction one of the two pump elements is fixed against rotation Whereas the other is not, which does not apply to all forms shown in my said patent to which reference is hereby made.

The following calculations will be applicable to the structures according to my invention on the basis set forth in the following mathematical discussion, in order to provide for a balance of the parts to assure a high degree of Vibrationless operation of the pump so far as its mountings are concerned.

Referring to Figure 5, in which AB represents a homogeneous member of length L and crosssectional area S, and having a specific gravity of P, whose axis p-asses through a fixed point O, and which is revolving about an axis O01 at an angular velocity of w:

If an element of this member, of a length dl is subjected to a centrifugal force, we have @Manac :substituting 'we get:

. cosa g y yThe resultant centrifugaliorce is:

"Thejmoment of the resultant Fwvith respect lto lthe point'O is equal `tothe 'sum 'of the moments lWith-respect to this "point of vthe elements `of centrifuga'lforce di, and:

FX: Italia Il Substituting the'va'lue for d? from (l) ,and the Yvalue "for Ffrom"('2)'in the above equation, we

Referring now to Figure 6 which shows in diagrammatic representation a rotor and stator, f1 is the resultant of the centrifugal forces acting on the rotor, and

fl Y

is the resultant of the centrifugal forces acting on the stator. The size and locatio-n of these resultants are determined according to Equations 3 and 4 above, and in general these resultants will neither be equal nor opposite. It is therefore necessary to add to the rotor and stator respee tively the balancing masses 'm and m1, providing the corresponding forces fm and fm1.

In order for the resultants F and Fl tobe equal, it is necessary that the vectors:

and in order that these resultants be opposite, it is necessary that:

6 with four unknowns '.(=Jm,.`lm,ffmhlmifandsincethe value'flm and .11ml will ausuallyfbe dictated/:by-:space requirements,.we se1ect'.fZm.-andlmlifronime range of values available, )determined-,he tierces ffm and fm1 by means of Equations 5 and 6, and then calfculate the lmasses m and .cm1 which `.will `provide Ithe requisitey forces fm nand-lffnl. The result :of course, will ibea dynamically b alanced apparatus. One other eiect to be considered because-of -'the l-ia'ct that -both r rotor zandlstator fare turning yin aliquidfis )that lof buoyancy/@of the liquid. For optimum balance, the weight :of Vthe .movingipants Ashould be equal Ito the-weight fof the li'quid they displace.

It will fbe clear .that Anumerous modifications lmay be A=rr1ade 'without'departingfrom the: spiritof my invention, iand therefore ldo not-intend Ito '-limit myself other-wise than faspointed-outiin claimswhichrfollow. y

lI-Iaving lnow 'full-ydescr-ibed -m-y linventiomwhat I Vclaim as -new and -desire "to #secure by-"Letters Patent is: i

-1. -In a :machine 'having two splral-elemen`ts 'one'inside Ythe other, the Vouter element-having done spiral vthread more thanthe inner element, each thread of which is constantly in contact-in each transverse section -vvithl the `outer element, the pitches of thefthreadsiorieach transverse cross section "of vthe elements; 'being in ithe ratio Yof the numbers 'of teeth; a casing in"wlriichsaid elem-ents are mounted, a'ldrive shaft 'icrsaiidiinner element rotatable Aon Yaiixed axis, a single articulating driving connection between said drive shaft and vsaidinn'er el-ement, Vand'` asingle articulating morncit'in'gj-for said outer lelement at Athe opposite vend from -'the articulation lpoint-of said inner element, so that each'iof'said-elements is 'free tomove"in-a conical '-path,=`the apices of said 'conical paths being Amapositely Y'directed relative to each other, and the axes Vof said outer and inner velements-being vat all times `'parallel toeach other;

`2. The :combination -of claim '-1 sum of the displacements of the inner and outer elements from a line connecting their apices is substantially a constant at all transverse crosssections of the assembly of the two engaged elements.

outer element is xed against rotation and the inner element is mounted so as to rotate within the outer element.

4. In a machine having two spiral elements one inside the other, the outer element having one spiral thread more than the inner element, each thread of which is constantly in contact in each transverse section with the outer element, the pitches of the threads for each transverse cross section of the elements being in the ratio of the numbers of teeth, a casing in which said elements are mounted, a drive shaft for said inner element rotatable on a xed axis, a single articulating driving connection between said drive shaft and said inner element, and a single articulating mounting for said outer element at the `opposite end from the articulation point of said inner element, said articulating driving connection and said articulating mounting being beyond the interengaged portions of said elements, so that each element is free to move in a conical path, the apices of said conical paths being oppositely directed relative to each other, and the axes of said outer and inner elements being at all times parallel to each other.

Since we thus have two Equations 5 and 6, 75 y5. The combination of claim 4 in which the sum of the displacements of the inner and outer elements from a line connecting their apices is substantially constant at all transverse crosssections of the assembly of the two engaged elements.`

6. The combination of claim 5 in which the outer element is fixed against rotation and the inner element is mounted so as to rotate Within the outer element.

7. In a machine having two spiral elements one inside the other, and each having an effective free end, the outer element having one spiral thread more than the inner element, each thread of which is constantly in contact in each transverse section with the outer element, the pitches of the threads for each transverse cross section of the element being in the ratio of the numbers of teeth, a casing in which said elements are mounted, a drive shaft for said inner element rotatable on a xed axis, a single articulating driving connection between said drive shaft and said inner element disposed beyond the effective free end of the outer element, and a single articulating mounting for said outer element at the opposite end from the articulation point of said inner element and beyond the eiective free end of the inner element.

8. The combination of claim 7 in which the sum of the displacements of the inner and outer elements from a line connecting their apices is substantially constant at all transverse cross-sections of the assembly of the two engaged elements.

9. The combination of claim 8 in which the outer element is xed against rotation and the ticulation with reference to said casing, a single flexible articulating means for mounting one end only of the rotor for articulation with reference to said casing, the articulation points for rotor and stator being at opposite ends of the casing.

l1. The combination of claim 10, in which the articulation point of the rotor is outside the pump casing.

12. The combination of claim 10, in which the stator is formed of exible material having a flange mounted iixedly in the casing.

13.V The combination of claim l0 in which the stator has a rotor engaging surface, at least, formed of flexible material.

14. The combination of claim 10 in which the stator is formed of rigid material, and a resilient element is secured to the rigid material and constitutes a flexible mounting therefor.

15. The combination of claim 10 in which the rotor shaft is provided with a flexible coupling located within the casing, and a drive shaft for the rotor mounted for rotation on a xed axis in the head of the casing. y

REN JOSEPH Louis MOINEAU.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED `STATES PATENTS Number Name v Date 1,892,217 Moineau Dec. 27, 1932 2,028,407 Moineau Jan. 21, 1936 2,267,459 Hait Dec. 23, 1941 2,290,137 Aldridge July 14, 1942 2,463,341 Wade Mar. 1, 1949 FOREIGN PATENTS Number Country Date 111,901 Australia Nov. 7, 1940 113,009 Australia Apr. 28, 1941 780,791 France Feb. 11, 1935

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