US2401189A - Rotary pump construction - Google Patents

Description

May 28, 1946. F. A. QujRoz ROTARY PUMP CONSTRUCTION Filed May 12, 1944 3 Sheets-Sheet mm vm Nm mw May 28,1946. F. A. QUIRQZ 2,401,189

ROTARY PUMP CONSTRUCTION Filed May 12, 1944 3 sheets-sheet 2 INVENTOR /CIQA/vc/Jfo A. Q/J//Qaz May 28, lgh F, A QUlRZ 4 2,401,189

ROTARY PUMP CONSTRUCTION Filed May 12, .1944 s sheets-sheet 5 tion throughout long continued use.-

Patented May 28, 194.6 l.

UNITED] STATE ROTARY rum CONSTRUCTION l sV PATEN 'rf 'OFFICE- Francisco A; Quiroz, Newark, N. J. A Application May 12, 1944, SerlalvNo. 535,283

-22 claims. (ci. 10a-117) This invention relates to rotary, pumps; more.

particularly to so-called screw,` of pumps, v

An object of this invention is ,to provide an improved screw type of pump construction that or lhelical -types will be inexpensive to manufacture and assemble and that will be of superior action l and eiilciency in practical use. Another object is to provide a screwtype of pump so constructed that a wide variety of different materials or combinations of materials may b e employed in making up its various parts and thereby readily accommodate the pump to any'of the. widely varying characteristics or requirements of different liquids to be handled. Another` object is to provide a pump construction of the last-mentioned character in which various of its parts are so constructed as uni-directional lateral thrusts imposed upon the rotary impeller. Another object is to provide, in

i pumps of the above-mentioned character, a

simple, inexpensive and dependable means` for opposing or counteracting Aend or side thrusts as the case may be, and capable, where necessary, of variability'of action where the thrusts to be opposed or counteracted vary within a cycle of operation of the pump.

Another object is in general to improve upon the construction, operation and efficiency of pumps of the rotary screw or helical type. Other objects will be in part obvious'or in part pointed out hereinafter.

Theinvention accordingly consists inthe features of construction, combinations of elements,y

to be easily replaced either by parts of the same material or by parts made of some different material, according to practical requirements met with. Another object is to provide a, pump construction in which its individua1 parts may be inexpensively fabricated and easilyv assembled or' replaced.

Another object is to provide'an improved screw or helical pump construction that will facilitate 4 the use of, and achieve numerous advantages resulting. from the employment of, relatively rigid though displaceable Or movable helical or screw elements, but in a manner to maintain effective sealing throughouttheir range of relative displacement or movement inrelation tov and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope ofthe application of which will 'be indicated in the following claims.

In the accompanying drawings in which are shown by way of illustration several of the possible embodiments of my invention,

" Figure 1 is a central vertical sectional view through the pump casing and its internal parts,

showing in elevation and in fragmentary longitudinal section one form of helical impeller construction;

v Figure 2 is a transverse vertical sectional view as s'een along the line 2 2 of Figure 1;

Figure 3 is a fragmentary horizontal sectional view, as seenalong the line 3-3 of Figure 1 and the `llne 3-3 of Figure 2, certain partis .being shown in elevation and other partsbeing broken away or omitted;

Figure 4 is a fragmentary end elevation as seen from the right in Figures 1 and 3;

l 4 Figure 5 is a transverse vertical sectional view pump construction that will have improved structural and operating characteristics. Another object is to provide a screw or helical pump construction in which inherent uni-'directional end or axial thrusts willlbe overcomeor opposed in a simple, practical and 4 inexpensive manner. Another object is to provide a., pump construction, in which the rotary impeller is eccentrically mounted, with simple. practical and inexpensive means for opposing or counteractlng generally as seen along the line 5--5 of Figure 1;

Figures 6 and 7 are elevations of, respectivelyl two forms of elements that make up the helical impeller of Figures 1 and 5 i Figure 8 is an elevation as seen from the topf I in Figures 6 and 7;

Figure 9 is a transverse sectional view as seen along theline 9 1 of each of Figures 6 and 7;

` Figure 10' is a view like that of Figure 1,` with certain parts broken away, showing a pump con(I I struction embodying a modied form of built-up impeller element, the latter being shown in ele vation and also in fragmentary section; and

Figure 11 is a development showing changes in v angularity with change in radial distance from the axis, of the side walls of a helical groove.

Similar reference characters refer to similar,

`of the pump cylinder made to the discharge or high suitable base or frame; p be in pairs, one pair near also prefer to embody ings.

Referring first to Figure 1, I provide a casing 20 generally cylindrical, preferably in the form of a casting terminating at its left-hand end in a relatively heavy annular flange 2i and at its right-hand end in a relatively heavy annular flange 22, the two iianges being coaxial but displaced relative to the axis of the casing 2li so as to be eccentric relative thereto.

The. casing 20 comprises what will hereinafter be termed the cylinder 23, the latter being bored out as at 24 preferably from the right-hand end so as to leave at the left-hand end thereof an annular shoulder 25 against which abuts the end of a preferably heavy-walled cylinder lining or liner 26 which at its right-hand end terminates substantially iiush with a machined annular face 2 formed internally of the casing 20 at the end of the cylinder 23. 'Ihe liner 25 is snugly fitted into the cylinder 23, being passed into it through` the opening in the annular end flange 22 of casing 20 and it is anchored in position and against displacement or rotary movement by any suitable means, such as, for example, one or more screws 28 which preferably functions both as a clamping means and as a key. For this latter dual purpose, a hole 3B may be drilled parallel to the axisr of the cylinder and liner, but so as to intersect the junction between the two, the hole is threaded, whence the screw 28 is threaded inward to -hold the liner 25 clamped against the cylinder parts throughout the several views of the drawof (see Figure 2), the channel 43 terminating at its left-hand end in Figure l into the inlet chamber 3|, preferably through a side wall thereof, and terminating at its right-hand end in the end flange 22 by which it is ultimately, as later described, to be placed in connection. with certain pendable drive of the rotor 45. j

end shoulder 25 and also .to hold it against rotary movement relative to the cylinder.

The casing 20, intermediate of flange 2| and the left-hand end of the left-hand the cylinder 23 'is shaped to provide a. chamber 3| of substantial size, hereinafter termed the inlet chamber, communicating with the left-hand end of the interior 23-26, and suitable means are provided for making a pipe connection to this inlet chamber 3|. Thus in a wall of the latter is cast a. transversely extending hole or passage 32 .terminating in an annulus 33 which is internally threaded as at 34 to receive the threaded end of a connecting pipe.

Intermediate the right-hand end of the cylinder 23 and the end annular flange 22 of the casing 20, the latter is shaped to provide a substantial-sized space 35 communicating with the discharge end of the cylinder 23--26, and chamber 35 will hereafter be 'called the outlet or balancing chamber ;y like the inlet chamber 3| it is provided able standards ory legs, indicated at 40, and suit-l ably distributed, so that it may be secured to a thus the standards may the inlet andthe other pair near the outlet end lvof the casing 20, the

standards of any one pair being preferably con- Y suitable cross web 4| nected and reinforced by a as is better shown in Figure contain suitable holes 42 for the reception of bolts or the like. y Y f In making up the casing 20, as by casting it, I

into it, asby coring. a pas- .sage or channel 43, for-med in a wall of the casing 2l, conveniently along the bottom portion there- 2. The standards 45 y bearing and packing gland housings line of tangency that elements inthe outlet or balancing I'chamber 35.

Within the cylinder 23-28 is operative a rotor 45 that is of a Iradius less than the radius of the chamber formed by the-cylinder 23-25I and which in length matches the length of the cylinhead part l53 that abuts against the right-hand end of the rotor 45, the part 53 being integrally formed with a hub 54 which carries certain other parts later described and which is secured to the shaft as by ataper pin 55.

In the solid-walled rotor 45 is formed as by milling, a helical groove or slot 56,1ater described in detail, and in the helical slot 55, which is preferably of substantial cross-sectional dimension, is mounted a helical impeller generally indicated by the reference y character 51, and preferably built up of component elements in the manner and for thel purposes and coactions -later described; the elements comprising the impeller 51 extend throughout the entire length of the helical groove 56, frompne rotor head 50 to the other with the axis of the assembly sufficiently displaced from the axis of the interior cylindrical surface of the cylinder hner 26 so that the latter and the rotor 45 are tangent to each other along a line of tangency indicated in Figures 1 and 5 by the reference character 58. It is along this the two relatively rotatably and tangentially arranged parts form a seal that is continuous, along the straight line of tangency, from one -end of the rotor or cylinder wall to the other. The elements that make up the helical impeller 51, however, have their outer faces of the same radius as the radius of .the cylinder f or` lining wall which theyvcontinuously contact during rotation of the rotor to maintain throughout the extent of the helical impeller 51 a sealed contact with the cylinder wall, being constructed, as is-later described, in relation to the side walls of the helical slot 56 to maintain a leak-proof seal between a wall or walls of theslot and themselves regardless of the extent of their displacement radially outwardly of the slot and regardless of certain peculiar variations in angularities in the side walls of the helical slot, all as is later describedin detail.

.The above-mentioned bearing structures for supporting, the shaft 46 to maintain the abovedescribed relationships of rotor and impeller to the cylinder wall during operation comprise two 60 and 6| assembled respectively to the annular end casing nanges 2| and 22.

receive the outer race 66 of Liquid supplied to the inlet chamber 3| through'- upon rotation of the Thus the housing 60 comprises a securing flange 62 one face of with the face of the casingange 2| a suitable gasket 63 being interposed therebetween, flange 2| having threaded therein a suitable number of suitably distributed studs 64 of a length to extend through correspondingly positioned holes in the fiange 62 and being threaded to receive nuts 65 whereby to achieve secure assembly of th'e housing 60 to the casing 20 and leak-proof compression of the gasket 63.

Housing 60, at its outer end, is bored out to an anti-friction bearing61 wh'ose inner race 68 is received over s, reduced end portion Iiia of the shaft and abuts against a shoulder 46h against which it is clamped by va sleeve and the hub 1I of one member v 12 of a flexible coupling 12-13, the clamping pressure being exerted by a washer 14 bearing against an internal shoulder of the hub 1| and pressed thereagainst by a cap screw 15 threaded coaxially in the left-h'and end of the reduced portion 46 of the shaft. The hub "Il is splined or keyed to the shaft portion 46H, as indicated at 16, to transmit driving torque to .the shaft, the driving Ivpower being applied by any suitable means to the coupling member 13 as by a shaft 11 which usually is the shaft of, for example, an electric motor, th'e flexible coupling avoiding need of precision of alignment of motor bearings and pump bearings.

'I'he outer race 16 may be secured in its supporting counter-bore by any suitable means which may comprise alsoI a ring member 18 rfitted into the counter-bore and bearing against the which is shaped to mate I outer race 66 and secured in position in any suit able manner as by screws (not shown) and the ring member may be suitably conformed as indicated to carry internally and about the sleeve 10 a packing or ring 80 of felt or the like to prevent ingress of foreign matter and to guard against leakage of lubricant from .the bearing assembly; a similar felt ring 8|, suitably housed in an appropriate counterbore in the casing 60 can similarly close off the other end of the bearing assembly.

Th'e inward extensionV of the mounting flange 62 is shaped and machined to provide a cylindrical housing 83 coaxial with the mounting flange 62 to form part of a stuffing box-or packing gland construction which may comprise suitable lgland packing 84 that extends about the shaft 46 and is compacted against an end iiange 'of the housing 83 by a packing gland 85 adjustably pressed into the housing 83 by means later described. Coaxial with the bearing and stuffing box structures is an annular rib 86 formed on, the inside face of the flange 62 tobe received within the bore 81 of the casing flange 2| to be thereby lcentered with respect to the bore 81; the axis of bore 81 is displaced in the same direction and to the same extent from'the axis of the wall surface of the cylinder 23-26 as is required to achieve tangency between the rotor and the cylinder wall surface, and hence assembly of the bearing 'and stuffing box housing 6U by its mounting flange 62 to the casing flange 2| achieves the desired eccentricity of support of the left-hand l end of the shaft 46 and hence of the left-hand end oi' the rotor 45. The mounting ange 62,

stuffing box and shaft 46 close off the bore81 in the casing flange 2|, thus closing oil' the inlet inFigurel.

the pipe connection 93-84 rotor assembly in the 4direction of the arrow in Figure 1, eifects movement of the liquid toward the right in the space between the cylinder wall and the eccentric rotor 45 in a manner later described in detail, injecting it into the outlet chamber 35. In th'eprocess, an end or axial thrust is imposed upon the rotor and shaft assembly, ltending to force the latter -in axial direction toward the leftvas viewed in Figure 1, and there is also'imposed a thrust upon the rotor 58 and its shaft 46in a direction transverse to their coincident axes, tending to flex the shaft and thereby4 shorten th'e life of the bearings and cause excessive or detrimental friction and rubbing between the rotor and the casing; this radial thrust being exerted mainly at the discharge or right-hand end of the rotor 45 for a substantial distance inwardly ofthe rotor by a distance-on. the order of the pitch of the helical impeller 51 and in a directiondisplaced about in leading direction relative to the d irectionof rotation, from .the line 58 oftheoretical tangency between rotor and -cylinder wall. Th'ese detrimental ac tions, dependent upon the above-mentioned leakproof relationship between the elements of the helical impeller 51 and rotor .and cylinder Wall, all, as later described in detail, I dependably overcome `by providing, in the other end casing structure 6|, means for opposing or ccunterbalancing both the axial thrust and the radial thrust, and for -that reason the other end casing 6l and the outlet or balancing chamber 35 and certain strucpart of the outlet chamber 35 and to control or" determine the application of the relatively high discharge pressure of the pump to coact in opposing the above-mentioned thrusts; conveniently, it has a relatively large and heavy annular flange 90, comparable to the flange 62 of the left-hand housing 60, adapted to abut against the casing flange 22, with a gasket 9| therebetween. Studs 93, suitable in number and suitably distributed. are mounted in and 22, and with the flange 90 providedwith similarly positioned holes to take over the studs which are threaded at their outer ends, the casing'6l may be detachably secured to the casing flange 22 by the application of nuts 94 to the threaded studs 93, thus also pressing fluid-tight connection. y p

The mounting flange 90 terminates inwardly in a cylindrical axially extending part 95 which is bored out as at 96 to provide an internal cylin drical wall that is coaxial with the axis'of the bearing housing 80 at the other end of the casing 20, and for purposes of assembly and of achieving such coaxial relationship. the portion 95 is turned as at 91 to provide an external cylindrical surface that is eccentric or radially displaced from the axis of the bore 96 by the same amount that the axis of the rotor is displacedfrom the axis o f the cylinder 23-26, they eccentric surface 96 being snugly received within the cylindrical bore 98 of the casing flange 22, the bore 98 being machined concentrically or coaxially'with the bore inthe casingcylinder 23-itseglf. r

The cylindrical portion 9 5 in eil'ect forms an endwise extension of the loutlet or balancing chamber I5 being closed oi! by an annular wall project from the casing flange the -gasket 9| to achieve vby a washer or disk l means of the sleeve r gland element |03 which is provided with suitable I neans for adjustably placing the packing material |02 under compression andhence under radial expansion.

From the end closing Wall of the housing 6|, the latter is extended to the right in Figure l to terminate in a cylindrical portion |04 that is internally bored out` to receive the outer race of an anti-friction bearing |06 whose inner `race |01 fits onto a reduced end portion 46c of the shaft 46 and is clamped against the resultant shoulder |06 held in clamping relationship by a cap screw ||0 threaded into the end of the shaft 46.

The end cap or'cover i|| closes oil the outer end of the cylindrical bearing support |04, bearing detachably secured in position as by studs and nuts ||2 (Figures 3 and 4), thus sealing off the outer end of the bearing mounting against loss of lubricant or access thereto of foreign material.

A suitable felt or like ring l|3 held in a suitable counterbore by a Aretainer ring ||4 seals off the other end of the bearing mounting against loss of `lubricant or entry of 'foreign matter.

Due tothe coaxial relationship between the cylinderbore 96, the stuffing box construction,

and the bearing mounting, of the housing 6|, in relation to which coaxiality the part 91 is turned to the desired eccentricity as above mentioned, the assembly of the housing 6|, as above described, to the end casing flange 22 brings all of the coaxial parts into coaxial relationship with the bearing and stuiling box axis in the other end housing 60 and the rotor 45 thus becomes assembled to the cylinder with their axes parallel but displaced and with the surfaces just about tangent along the line 58 as above described.

Within the endwise extended outlet chamber 35 and mounted to rotate with the rotor, I provide a balancing rotor generally indicated by the reference character IIB and conveniently I form it integrally with the rotor and head 53 and its hub 54. Rotor ||6 is of an external diameter on the order of the diameter of cylinder wall 26a; thus it may be equal to the external diameter of the rotor 45 where the difference in diameters of cylinder wall 26 and rotor 45 is not too great, and its external cylindrical face ||1 is coaxial with the axis of the shaft 46 and of the rotor 45; this cylindrical face ||1 coacts as later described to effect the above-mentioned radial thrusts and it is preferably constructed to be hollow, strong and rigid,'having for example a plurality of ribs ||8 extending radially fromthe internal/face of the rotor H6 to the hub 54 to give the right-hand or outer portions of the rotor ||6 cantilever-like internal support. This structural relationship aids in making. it possible to have the stuflng box s housing |0| extend axially inwardly within the right-hand open end of the balancing rotqr H6,

' -thus permitting shortening up of the axial distance between the end bearings supporting the shaft 46.

The nouow rotor Hs is otherwise joined to the hub 541by an annular wall |20 which is spaced a substantial distance axially from the end face of the rotor 45, and it presents toward the rotor -end face an annular end facei |2|, and it also `presents internally of the cylinder 6 an annular face |22, both of which take part in offsetting axial thrustcaused by the operation ofthe helical pump elements. t

, Theend face |2| is subjected to the pump discharge pressure, the outlet chamber 35, and the pressure of liquid in the latter is thus exerted against the face I2 I, tending 'to thrust the rotating structure toward the right in Flgure 1, thus to oppose the reaction of the helical irnpeller 51 and rotor 45 in exerting a thrust toward the left, provided that the outlet pressure'is not made effective upon the opposed face |22 of the annular wall |20.

d iIn part to realize this last-mentioned condition,

v I provide a seal between the external cylindrical face ||1 of the balancing rotor H6, and the interior of the cylinder portion 95 of the end casing 6|, and this seal I achieve by what I shall term a sealing ringf? generally indicated in Figure 1 by the reference character |25 secured to the face 96 of the cylinder 95 and relative to which the balancing rotor l|6 rotates. Since the sealing ring |25 coacts with the rotor ||6 for purposes later described, its construction and mounting are described later in greater detail.

The sealing ring |2-5 thus seals off the interior of the hollow balancing rotor ||6 and hence also the internal annular face |22, from the high or outlet pressure in the chamber 35, and by Way of a. channel or passage |26 formed inthe end casing Ei and mating with the channel 43 extending lengthwise of the pump casing 20 itself, the in.

terior of the hollow balancing rotor ||6 and the tion with the inlet chamber.

Axial thrust toward the left, caused during the operation of the rotor and helical lmpeller 51, is a functionof the difference between discharge pressure and inlet pressure, and the actual thrust in pounds is the product of that difference in discharge and inlet pressures (in pounds per square inch) multiplied by the area (in square inches) throughout which that difference is effective, and

that area, in generaL- will be the difference between the cross-sectional area of the bore of the cylinder 23-426 lessI the cross-sectional areaof the hub 54 to the left of the annular face |2| of the balancing rotor H6. This yaxial thrustvis opposed by the diierence between the force exerted by the discharge pressure in the balancing chamber 35 against the external annular end face |2| of the balancing rotor ||6 and the force exerted by the intake pressure; communicated to the balancing rotor ||6 by the passages 43 and |26, against the effective surface areas of the balancing rotor ||6 exposed thereto, and they comprise principally the internal annular face |22. As a result, the balancing rotor ||6 exerts an axial thrust toward the right which, according to'dimensional factors that are selectedin relation to the diierence between the discharge pressure and the inlet pressure 'for which the pump is designed may in whole or in part balance or oppose theaxial thrust towardthe left caused `by the operation of the pump rotor 46 and impeller element 51.

The anti-friction bearings 61 and |06 are preferably of the combined radial and axial thrust type so that they can take up any resultant axial thrust that may exist or may be caused during the operation of the apparatusl Considering now how the balancing rotor ||6 `rcompensates for radial thrust, itis first to be -noted `that the action ofI the rotor45 and impeller 51 is such that this radial thrust upon the rotor being the pressure existent in i' posing a greater axial length lci surface of thel posed to the 9 the discharge end being throughout an axial distance at least equal to the pitch of the helical impeller 51 and its maj horizontal direction, namely, at right angles to and toward the plane of Figure 1, or in a direction toward the right in Figure E from the 9 oclock point of they I provide, by appropriate construction, preferably by suitably shaping the sealing ring |25, for exbalancing rotor |6 to the outlet pressure always at the 3 oclock point which is diametrically opof the pump cylinder 23-26 and from which 9 oclock point the major eiiect of the radial thrust is exerted radially inwardlyupon theV rotor.'

The sealing ring |25 comprises, in general,.a truncated cylinder liner |215a whose external diameter matches the internal diameter of. the bore 9E of the cylindricalportion 95 of the end Acasing 6|, the portion 95 being, as is better shown in .Figure 3, and indicated by the broken line i |21,

the sealing portion rotor and pump cylinder, thus insures that a in a direction' opposed the member I 5 also vshapedjin the form of a truncated cylinder,

the above-mentioned 9 two dimensions being better shown in Figure 3 by the lines |21n and |211.

or eifect, instead of being directly downwardly as seen in Figure 1, is in a cross-section. Accordingly,-

" charge balancing vout of oclock point in the cross-section having its -minimum axial dimension at the above-mentioned 3 oclockvposition and its maximum axial dimension at Ioclock point in the vertical cross-section, these The external diameter of balancing rotor IIS is preferably less than thediameter of the cylinder wa1l`26aand equal to or greater than the diameter of the pump rotor 45 and the liner |25a Vis of lesser thicknessthan the difference between the diameter of the bore 96 in which it is tightly fitted and the external diameter of the rotor |I6, excepting throughout the sealing portion .I 25b thereof where its thickness matches the juststated difference in diameters so as to provide a snug and sealing surface engagement with the "rotating balancing rotor II 6, somewhat like a packing gland.

l As shown in Figure l, the axial extent of'this sealing surface engagement is preferably substantial and peripherallythe extent is 360 and continuous but at an angle to the axis. equal to the pitch angle of the' helical impeller 51 of the pump. This relationship appears betterI from Figure 3 where the angle is indicated at X.

The sealing ring structure |25 is xed within the bore 95 in any suitable way`so that it will not be displaced axially or in a rotary direction,` 'as by sitable locking pins I 28 anchoredin the cylinder portion 95 and extending intovsuitable holes in The labove-described shapeI and disposition oi? |25, inrelation to the4 pump truncated portion I |1 ofthe external surface I I1 of the balancing rotor IIB, with' the maximum axial .dimension always at the 3; ofclock position,

is a lways exposedto .the-pressure in.the\outlet chamber 35,l and 'insures that the remaining truncated portion" LH1", having 'its major axial dimension always' at the 9 'oclock position, is

pump inlet pressuretby the y isvthus always exerted upon the-balancing rotor IIB-and that thrust is to the radially inward A thrust radially inwardly.

. the integrated product axis of the rotor 45; l each has a radius equal to the radius of curvature of the wall 26al l 2,401,189 y 5 is exerted mainly in the axial region of the rotor thrust from the 9 oclocl: position exerted upon near its right-hand or discharge end as viewed, the pump rotor.

.in'Figure l, the principal radialeffect adjacent The parts are proportioned and dimensioned as above illustratively described, and the euective high pressure-in the outlet chamber is made large enough so that the product of the pressure multiplied by this area is substantially` equal to of the pressures (which increase progressively from the inlet to the disend of the rotor) eii'ective upon the exposed areas of the pump rotor during the operat on of the pump, thus achieving substantial radial thrusts, Preventing tendency to deflect the shaft 40 and preventing misalignment at the theoretical line of tang'ency 58; such misalignment could cause wear of the relatively moving parts with consequent impairment 1 of eiiiciency and pumping action. 'I'he general proportioning of the parts oi' the balancing rotor I I6, as shown in the drawings, is alli-4 pump structure of thepropriate in relation to a number of turns of helical impeller 51 as shown lin Figure 1; where the pitchr of the turns is changed so that the radial thrust to be overcome is of a different order of magnitude, corresponding changes in proportioningof thebalancing mechanism will, it is understood, be made.

.To achieve appropriate seal between -the helical impeller element 51, the pump cylinder 23-28, and the helical groove 5B, I construct the helical element 51 to have, and'to maintain during its continuously changing radial' position relative to the helical groove of slot 55; a reliable sealing relation with at least one wall of this groove. In the form shown in Figure 1, the helical impeller 51is m de up of a plurality of individual elements or members |30 which have leading and trailing faces |30 and |30b,re spectively, that extend in planes at right angles to the axis of the helix 51 and hence also the the outer edge face |30 of of the cylinder 23-26 and an inner edge' face |30d (see Figures 6 and 7) that has a radius of curvature equal to a dimension that is the radius of the outer edge face 130 less the depth ofthe helical groove 56.

'I'hus each outer edge face I30 c an make sealing contact, throughout its entire area, with the cylinder wall 28n and all oi.' the elements |30, whenassembled in the helical groove 53, make such sealing engagement with the cylinder wall t groove 50.

. ber of turns and 28, while the irmer yedge faces 'I30i can make tangential sealing contact with`the groove bottom 50 when necessary, namely, helical element 56 pass through the 6 oclock position at the theoretical line of tangency 53, the radial dimension of the elements |30 being not greater than the radial The members |30 .are all o'f identical shape and construction so that, when assembledwith their leading and trailing faces |30* and |30 in contact with each other, they make up a helix of the desired numof an outside diameter equal to the diameter of the cylinder wall 26"; the justmentioned contacting faces 13N-|30b will -be seen to be of substantial areas so that each member. |30 finds and receives substantial support from an adjacent one as against thrusts, exerted in an axial direction .aswhen forcing liquid, in

the pump chamber C, from the' left toward the right lin Figure 1, and they receive as a whole or when the rotor and depth 0f the helical and there are enough of them as an entire unit, rigid support from the side walls tb and 56c of the helical groove 56; in this latterl connection, it is to be noted that it is preferred to so dimension the parts that, at the 12 oclock position, the members |30 or the helical impeller element 51 as a whole project from the groove 56 by only about one-half of their radial dimension.

The length inra circumferential direction of the members |30, that is, of the outer edge face l30c, is equal to an arc of the same number of degrees as .the outer arc of a cross-section of the helical groove -513 taken at right angles to the axis of the rotor 45, and with that dimension as a base,

` the circumferential dimension of the Yinner edge face |30d follows according to the shapes given the end faces |30e and |30f which are to contact directly with the side walls 56 and 56b of the helical groove 56; these end faces are helical, or segments of helixes.

Because the groove 56 has substantial depth, the walls 56| and 66 not only are helical but also of varying curvature with respect to a plane extending at right angles to the axis of the rotor, the curvature varying as the radius or diameter changes from the minimum radius at the bottom wall 56a of the groove to the maximumradius at the surface of the rotor 45. Though the pitch i is the same throughout, the pitch angle, that is,

the angle of a tangent to the curved groove side wall with a plane transverse to the axis of the helix, becomes less as the diameter increases, and in Figure 11 I have shown the change in this angularity for a rotor having a 4" diameter, and a pitch of 4" for the groove (that is, the helical groove completes one-turn of 360 in 4" of axial length of the rotor). Thus, the above-mentioned angle with the radial plane, at the maximum radius of 2 is 18 and the angle at the minimum radius, that is, where the side wall of the groove intersects the bottom wall, is 32. Now, the end edge faces |30e and|30f are given helical curvatures which vary progressively, with a maximum outward displacement of themembers |30 from the groove 56 of 1/2" (at the 12 oclock position), of 271/2" where these end edge faces intersect with the inner edge face |30d to 201/2 where they intersect with the outer edge face |30, this range of values will be seen to-be the middle half range, so to speak, of the range of change in angularity of the side walls of thegroove 5B itself.

The end edge faces |30e and |30f of the members |30 and hence the side faces of the impeller element 51treated or considered as a whole, arev thus helixes of the same pitch as the rotor groove but of such different range of change of pitch angularity that, I have discovered, gives the helical impeller 51 not only a desirable flexibility of self-adjustment or self-accommodation to the groove as to achieve dependability mechanically of operation, but also insure such contact with particularly the trailing side wall 56b of the groove, throughout the continuously varying displacement of the elements |30 radially, as achieves a dependable seal between the end edge faces |30 and the trailing sidewall 56h, even though the lines or areas of generally tangential contact therebetween continuously shift radially according to the change in radial distance of the members |30 from the bottom of the groove.

I emphasize the contact` between the trailing end faces |30t and the trailing side wall 56| befcause the resistance or back pressure o'f the liquid being moved towardthe right along the chamber C, coupled with a reaction tending to force the `by the helical groove members |30 individually in a. direction opposite to the direction of rotation, presses the end faces |30t against the trailing side wall 56b of the groove and, with continuous though variable contact always maintained therebetween, reliable sealing against leakage from the highvpressure sides of the helix 51 to the low pressure side thereof is achieved. This sealing action is supplemented by the pressure with which the members |30 are maintained flatwise against each other at their adjacent contacting. plane side faces |30a and |30b and the substantial expanse of these engaging side vfaces coacts with the end edge faces in supporting the'elements |30 against tilting. For example, viewing theleft-hand half turn of the impeller 51V in Figure 1, the circumferential extent of any one element |30 and hence of its trailing side face |30b is great enoughy to overlie, in projection, two, three, or more helical end edge faces |30t of as many succeeding or trailing elements |30.

The above-mentionedsealing contact effected at the trailing end faces |30I guards against leakage not only as above described but also against leakage of liquid being pumped along the continuously varying (in volume) chamber B formed 56 and the helical impeller 51 whosepumping capacity supplements that of the sealed chambers C progressively advanced from the left toward the right externally of the rotor 55 per se. Liquid enters the left-hand terminus of the slot 56 through suitable passages in the rotor head 50 as that end terminus is progressively opened up in turning fromthe 6 oclock position to the 12. oclock position in Figure 5, whence progressive closure thereof ensues from 12 oclocls to 6 oclock via 9 oclock, the entered In this connection, the end head 53, shown in end elevation in Figure 2, is provided with a discharge opening |32 that overlies the right-hand terminus of the helical slot 56 in the end face of the rotor 65; the extent of the terminus of the slot in that end face, in circumferential direction, is substantial because the slot is helical and of substantial width in axial direction, and is indicated at 56g in Figure 2; the opening |32 in the end head- 53 is of substantially matching peripheral' or arcuate extent and the leading and trailing end walls |32 of the opening |32 are bevelled off at about 45 to effect smoothness of egress of liquid under pressure.

The discharge opening |32, however, overlies only about the inner half of the radial extent of the slot terminus 568, so 'as to leave'the arcuate portion 53 of the head 53 to close off the outer half portion of the slot terminus 56H and thus form a physical abutment for therendmost member |30 of the impeller 51, engaging the part 53'by way of a front or leading :face |30 thereof. To avoid unbalance, because of the discharge opening |32. a diametrically opposed portion of the head 53 may be hollowedout as at .'53b (Figures 2 and l).

The head 50 at the inlet end of the rotor is provided with an arcuate inlet opening |33 similar to the just-mentioned discharge opening |32 in the head. 53, and its leading and trailing end example, at about with respect to the 45, in directions to function, direction of rotation, as scoops to aid in injecting liquid from the inlet chamber 3| into the inlet terminus of the helical groove A56. Head 50 may be hollowed out as at 50", diametrically opposed to the inlet opening |33, for balance. In Figure 1 is shown in cross-section the lportion 50B, corresponding to the portion 53 of Figure 2, that overlies about the outer half of the inlet terminus of the groove 56 and against which the endmost member |30 abuts and is sup- DOrted. ilatwise. by its trailingr side face |30b.

Maintenance of the elements |30 in position to make continuous sealing contact with the cylinder wall 26 is aided not only by their structural interrelationships to the helical groove 56 but also by the centrifugal forces acting upon them as they are rotated. I prefer, however, also to supplement these actions and thus, referring to Figures l, 6, 7 and '9, I preferably bevel off the inner edge faces |30d, as at |308, throughout their arcuate extent but only along. the trailing portions thereof this insures postiveness of entry of liquid underneath the elements |30 when they are Ain engagement with the bottom wall 56a of the.

groove 56 `te insure against'v tendency to create a vacuum between them and the bottom wall 56, which would tend toresist outward radial movement of the elements 30, and, with the forceful advancement of liquid )along the helical groove 56 as above described, such entry of liquid under pressure operates in effect as a progressively acting hydraulic lift for the elements |30 to force them outwardly, aided by centrifugal force, and thus insure that they always are in sealing ensagement with the cylinder wall 26. 'I'his bevelling oi of the under or inner edge faces also afds, at the'entry terminuscf the groove 56 adjacent the inlet chamber 3|, in achieving initial lift or outward radial movement of those mem-l Abers |30 that become directly exposed to the inlet terminus of the groove 56; in this latter connection, the s cooping or impeller action effected by the bevelling of the radial end faces |33B-of the ,4 entry opening |33 in the rotor head 50 coact to inject yliquid and give it force or pressure to provide initial `lifting action if the latter necessary. 'I'he construction thus far .described makes possible a variety of combinations of materials capable of employment. Thus the liner 58 and the members |30 may be made of any suitable material or materials capable oie appropriate coaction in relation to the liquid being pumped. For exbecomes ample, if -oils or other self-lubricating liquids are being pumped, these parts may be made of metal or of any combinationof metal and non-metallic parts that are appropriate. If water or other non-lubricating liquids are to be handled, the

rotor may be made of any suitable non-corrosive metal, such as stainless steel, the'members |30 may be made of a non-metallicmaterial, such as .hard rubber, any suitabley plastic, compositions like so-called Micarta 58 may be made of suitable plastic water-lubricating compositions. ,If the members |30 are made sity might give them a weight that might result in excessive centrifugal forces, the members |30 may have one or more holes drilled in them, as indicated in Figure 6 at |3011; the hole or holes being dimensioned or positioned so that they do which operate with waterl as a lubricant, and theliner of metal whose den-4 of the helical slot material and prove to be insumciently heavy to give the desired effect under the action of centrifugalforces, suchhole or holes |30h may be filled with a metal like lead, as indicated at |34 in Figure 7, thusadding to the weight of each member |30 `as may be desired.

In Figure 10, I have shown another form of construction for the -helical impeller 51 which is also self-accommodating to the side wall or walls 56 to achieve suitable assurance against leakage between contacting faces of the varyingly-angled sidewalls of the groove and the faces of the impeller 5'|.` 'I'he helical impeller of Figure 10 is also made up. of a plurality of elements; these are indicated individually-by. the vreference character |35, and each'member |35 is preferably-a complete helix in and of itself, of

as'many turns as there are turns inthe helical groove 56, having an outside diameter matching the diameter of the cylinder wall 26n and having an inside diameter of suchdimension 'as' will give each helical member |35 a radial dimension equal to the depth of the helical groove 56. The members |35 are of relatively small thickness and illustratively may be made of any suitable metallic or non-metallic material; their relatively small thickness gives them individually considerable flexibility, preferably spring-like or resilientfand a suitable number of them are assembled to give the helical impeller a thickness to be snugly received ,within the helicalgroove. At suitableintervals throughout the resultant composite helix, as for example every 3" or so, the members |35 vmay be secured together, as by cross-pins or rivets |36, the securing action .the plurality ofhelical plate-like members |35 against relative displacement in a radial direction, thus to maintain their outer edge faces |35c in alignment to form substantially a continuous face or surface for sealing contact with the cylinder wall 26B. The composite helix may have, or may `be given by construction, a tendency to expand and such action, being substantially spring-like or resilient, Imay if desired contribute toward maintaining the just-mentioned sealing contact. l

The spaceunder'neath the composite helix and between the aligned inner edge faces |33cl and the bottom wall56 of the helical groove, which varies progressively during the operation of the pump and is progressed from the inlet end to the A outlet end of the groove so that it is effective also can thereby also beutilized' to insurey internal outward radial pressure against the composite helix At the inlet and outlet ends of the helical groove 56, partially closed oft" by the portions 50B' 50 and 53, reterminate in end fall in planes respectively coincident with the end not overlap when the members .|30 are assembled to form the' impeller y51, the hole or holes being of sufficient ,size to 'reduce the weight of the member.

If the members |30 are made of a non-metallic Vevery 360,l I provide a radially faces of the rotor "45, thereby abutting .at the respective ends of the composite helix against the arcuate head portions 50 holding the built-up helix against tendency `to creep or thread itself Preferably, at suitable intervals, for example, extending stud |31, preferably in the form of a headless screw threaded into the rotor and thus grooveand, in assembly, threaded through a hole |30 drilled through the composite helix-thus to being appropriateto'hold to achieve the above-men-v tioned sealing contact with the cylinder wall 26B.

to the helix' and I and 53 to aid in along the helical groove.l

projecting outwardly from the bottom wall 56a of the helical reactions during pumping as tend to cause creepage of the helix along the helical groove.

The holes |38 for studs |31 are preferably given a shape approximating an hour-glass, or may contain a yieldable rubber bushing, and studs |31 terminate at their outer ends at or within the cylindrical plane of the surface of the rotor 45 so that they do not project out oi the helical groove and still provide lample radial length to maintain sliding engagement with the composite helical impeller and permit change in relative angularities as the impeller partakes of relative radial inward and outward movements with respect to the bottom wall, 5680i the helical groove, as in passing from the 6 oclock position to the`12 oclock position and from the 12 oclock position to the 6.oclock position. The studs |31 thus prevent such reactions upon the helical impeller as tend to'expand it from actually expanding the impeller to extents as would create 'excessive friction or as would cause jamming between the impeller and the cylinder wall 2B?.

The holes'l38 in which the studs |31 engage, being preferably shaped as above described or containinga yieldable bushing, provide some extent of play toward the right or left as viewed in Figure of the composite impeller relative to the groove 56; this relative playallows also for changes in angularity of the impeller, or portions of it, somewhat in a direction transversely or the helical groove. This play is desirable so as not to detrimentally interfere with the resilient exing of the plate-like elements |35 individually and as a unit for purposes of achieving selfaccommodation, due to the resultant flexibility `of the helical impeller, of the trailing side face |35. to the trailing side wall 55h of the helical groove, throughout the changing angularities of this groove side wall 55h at diierent radii thereof, as above explained, so as to maintain continuity of sealing engagement for Whatever radial position that the composite helical impeller has relative to the groove 58. The reaction of the liquid pressure being built up as the pump forces liquid from the inlet chamber toward the voutlet and balancing chamber is in a direction to press the helical impeller always against the groove side wall 5th and the laminated structure of the impeller gives it such resiliency and flexibility as permits each turn or portion o f a turn of the helix to yield or iiex, about radial axes, relative to an adjacent turn or adjacent portion as will eiect maintenance of sealing contact at the traili ing groove side wall 55h for any radial position of the impeller relative thereto.

This resilient ilexlbilityit will now be seen, may be easily predetermined for various practical conditions and for various sizes and designs or capacities of pump construction. Thus, according to the material employed in making up the members |35, they may be made of diEerent thicknesses according to the yieldability desired or needed to maintain the above-described selfaccommodating sealing action.Y The members |35 may be made up oi' metal or of non-metallic material, such as relatively hard or rigid rubber,lresinous compositions, so-calledplastics, or the'like, and anycombination therewith 4of different materials for the cylinder liner 2|ifrnay be made up according to the requirements of the particular liquid to be handled. Y

In achieving adequate maintenance of sealing between the built-up impeller of Figure l0 and the wall or walls of the helical groove 53, the axial and radial thrusts exerted by or upon the rotor become substantially determinate and the balancing rotor IIB `and its related parts can be constructed and proportioned to achievel adequacy of compensation or oounterbalance and thereby also achieve the advantages structurally and functionally earlier above described. With either of the illustrative forms of composite or built-up helical impellers, it is preferred that the helical groove 56, if only a single groove and impeller are employed, be not less than twol turns and if two grooves and impellers are employed each groove and impeller should be not less than one and one-half turns, to avoid the existence of a continuous or free passage from the inlet chamber to the outlet chamber. In general, each additional turn 'adds another stage to the pump. The features of my invention are, it will now be seen, readily adaptable to these and other variations.

Whatever the number of turns or number of heliXeS emplyed, and this is true of the impeller structure of Figure land also of the impeller structure of Figure 10, the members |30, being in a sense laminations in planes transverse of the axis of the rotor, andthe members |35, being laminations in helical planes of the helical impeller, coact with each other and with the cylinder wall and walls of the helical groove to give multiple sealing actions. For example, these members individually engage the cylinder wall 2t and in each case have enough freedom of relative movement to be individually seated snugly against the cylinder wall; each such seating achieves sealing action and these seatings and sealing actions are multiplied, due to the laminated arrangement or due to the overlapping of the members, in a direction I axis, that being the direction in which successive closed chambers are formed between the rotor, turns of the helical impeller, and cylinder wall and progress toward the right in Figures l and l0. Leakage out ofsuch chambers would tend to take place-in reverse direction, namely, toward the left; multiple sealing takes place between these impeller elements and the cylinder wall as just described and in a sense the sealing may be said to take place in a succession of individual stages. In both forms, leakage, in the just-stated direction, between the impeller and the rotor is guarded against by the flexibility of the helical impeller as a whole and the self-accommodation of its trailing helical face of the individual end faces if and made up by the trailing end face |35' inthe form of Figure 10) to the varying angularities of the wall 56h of the groove, varying with the radial distance from the axis. v

If desired from the viewpoint of manufacture, in the of any desired arcuate extent, the sections of any one complete helical lamination |35 being in abutting end to end relation throughout the complete length. of the helix, cessive complete helixes |35 suitably staggered relative to one another; when so built up, the rivets or'pins |36, which may be positioned in the lower half of the impeller assembly so as not I to be exposed out of the helical groove 5B when-V in the 12 oclock position may again be used to hold the laminations against material relative radial or circumferential displacement, and these pins may be located'so as to assemble all of the sectionalized. laminations into a, single unitary helix or into sections oi' the helix of each comlengthwise of the (made up in Figure 1 with butt joints of suctent and adjacent ends of such helixsections being in 'effect interttedv as in a nrio'rtisev and tenon joint, due tothe above-described staggering of the sections of individual helixes.

InFigure 10, certain of the intermediate laminations or 'elements |35 are indicated as sectionauzed by thev lines lass' which indicate end to end vabutting relationships of successive sections. Inwhatever way. the members |35 are sectionalized it is preferred that the two outermost elements |35, being respectively the leading f and trailing elements of the Ahelical impeller be continuous throughout the length of the helix.

Sectionalizing as above described also has the added advantage, particularly with certain relatively stii materials, of giving wider range of flexibility, about radially extending axes, one portion of the helical impeller relative to an adjacent portion, lthus tol better 'achieve continuity of sealing engagement throughout the 'varying' angularities of the trailing side wall 56b of the helical groove.

The gland element |03 of the 4stuiiing' box within the right-hand end casing 6| (Figure 1) is.

provided with suitable means for adjusting the' pressure it exerts uponthe packing material and for removing it to replace the. packing material, and for this purpose the side walls of the housing 6| are cut away as at |40 and.| 4| to give access to suitably mounted studs |42 and nuts |43 by which a, cross-bracket |44, which bridges across the right-hand end of the stuiiing box element I. |63;y a' similararrangement, not shown, is provided for adjusting and removably holdingthe packing gland at the left-hand end of the shaft 46, the housing 60 at that end being suitably cut away as at |45 and '|46 to give access thereto.

As appears better from Figre 1, the sealing portion |25b ofthe sealing ring will be seen to coact also in lessening the burden imposed upon the above-mentioned stuing box in the end casing 6|, forl it seals the liquid under discharge pressure in the discharge chamber olf from the inner end of the stulng box which thus becomes exposed to the low pressure .of liquid communicated to that portion of the balancing chamber bythe passage 43|26 that leads from the inlet chamber 3|.-

'I'he communicationof low or inlet pressure liquid from the inlet chamber 3| to the low pres- 1 sure surfaces or'areas of the 4balancing rotor |||k in the balancing chamber 35 may be effected by other or additional means than the cored-out passages 43 and |26, and this I do by a preferred construction which I am enabled to cause to coact to achieve, when desired, certain practical advantages.

For example, for certain sizes orzcapacities of Dump construction.- itmay be desirable or necessary that the shaft 46 be solid throughout, and

in such case the inlet chamber 3| and the sealedoif portion ofthe balancing chamber 35 are 'connected together in, for example, the manner above described, such as the cored-out passages 43 and |26; but for certain other sizes or capacities of pump construction, particularlyconstructions where it may be undesirable to disrupt the external cylindrical surface of the casing 20 as by the longitudinally extending bulge formed by the passage or channel 43, I prefer to provide the 2,401,189 9 posite section being of. appropriate arcuate ex- In the latter case, and also where it may be desired to supplement the communication provided by the cored passages 43|26, ,I construct the shaft 46 as is better shown in Figure 1; Thus,

I may provide the above-mentioned shoulder 46h adjacent the left-hand end of the shaft and the shoulder 46d adjacent the right-hand endof the shaft by the respective annular faces of a heavywalled tubular shaft portion 46 having therefor an internal coaxial channel 4BP extending therethrough from end to end, in which case the lesser- 'diametered shaft portion 46'l at the left-hand end has a plug-like lesser-diametered extension 46 tted into and closing off the left-hand end of the channel 46p and the lesser-diametered shaft part 46c at the right-hand end has a similar lesser-diametered plug extension 46*z extending linto and closing oir the right-hand end of the channel 46p. These interiitting parts may be mechanically secured against coming apart in- With such an arrangement and for certain capacities or pressure ranges of pump construc-V tion, I am also enabled to gain the advantage of the characteristics of the tubular cross-section of the shaft portion 46 in offering greater rel sistance to flexing per cross-sectional area of communicationbetween inlet chamber 3| and the sealed-olf portion'ot the balancing chamber 35 by means of a passageway extending through and coaxially of the shaft 46 itself.

metal employed than does a solid shaft and these features may be made to coact `in lessening the radial-thrust-opposing burden carried by the balancing rotor.

It` will thus be seen that there has been proy vvided in` this invention .pump constructions in which the several objects hereinbeforepointed s out together with many vthoroughly practical advantages are successfully achieved. The oo nstruction, as a pump, is dependable, eflicient, compact and durable, and manufacture and assembly of its various parts may be carried on with emciency and at reasonable cost. VFor example, the component parts of the helical impeller constructions may beindividually made up in quantity, being substantially identical or standardized for a given capacity or for respective practical conditions of operation, and may be readily and inexpensively assembled to the rotor in the form of a composite helical impeller. It will also be seen that a wide variety of practical pumping requirements, such as diversity of liquids to be handled, may be with facility and emciency met in a thoroughly practical way.

As many possible Vembodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter here-- inbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense. c

I claim: l

1. Apump construction comprising a casing having aninlet chamber and an outlet chamber joined by. a cylinder, with a lesser-diametered rotor within the cylinder rotatably mounted to j response to liquid under I spective'.

ancing rotor to seal off from the pressure of liquid in said discharge chamber all of said cylindrical surface excepting a portion thereof displaced substantially 180 from the direction of radial thrust exerted upon said first rotor.

2. A pump construction comprising a casing,

' having an inlet chamber and an outlet chamber joined by a cylinder, with a lesser-diametered rotor within the cylinder rotatably mounted to be substantially tangential to the cylinder wall along a line of the latter, said rotor havingmeans comprising helical impeller means in sealed connection withv the rotor and making sealed contact with said cylinder wall and means for accommodating said impeller means as it passes through theV line of tangency, whereby said rotor and impeller means are subjected to an axial thrust that is a function of the pressure in said outlet chamber and the pressure inv said inlet chamber,

a balancing rotor coaxial y with means sealing the one off from the other, and means subjecting said two surface areas respectively to the pressure of liquid in said discharge chamber and to presbalancing rotor exerts an 'axial thrust that is a function of the difference of said two pressures and in a direction opposed to said first-mentioned axial thrust.

3. A pump construction comprising a casing havinga cylinder therein terminating at its respective ends in an inlet chamber and an outlet chamber, a shaft having thereon a rotor of lesser diameter than said cylinder and extending at its ends through and in sealed connection with the y outer end. walls of said casing with bearing means rotatably supporting it to rotate upon an axis such that said rotor is substantially tangential to the cylinder wall along a line of the latter, said rotor having means comprising helical impeller means in sealed connection with the rotor and making sealed contact with said cylinder wall and means for accommodating said impeller means as it passes through the line of tangency, whereby, during pumping action of said impeller means,

difference between the to the said rotor having means comprising helical impeller means in sealed connection and making sealed contact with said cylinder wall and means foracccmmodating said impeller means as it passes through the line of tangency,l

said shaft carrying a balancing rotor having a surface of revolution with means sealing off 'from the pressure of liquid in said dischargewchamber all of said surface of revolution excepting a portion thereof displaced substantially 180 from the direction of said radial thrust exerted upon said rst rotor;

5. Apump construction as claimed in claim l. in which said sealing means extends perlpherally about said cylindrical surface with. a bounding edge thereof falling in a plane that intersects the axis of said balancing rotor at 'an angle whereby the said portion of said cylindrical surface that i is subjected to the pressure of liquid in said discharge chamber is in the shape of a truncated Lcylinder` whose effective area is displaced sub-` stantially 180 from the direction of radial thrust exerted upon said first rotor.

6. A pump construction comprising a casing having an inlet chamber and an outlet chamber joined by a cylinder, with a lesser-diametered jwith and connected to said first rotor and having opposed surface areas sure of liquid in said inlet chamber whereby said rotor within the cylinder rotatablymounted to be substantially tangential to the cylinder wall along a line of the latter, said rotor having means comprising helical impeller means in sealed connection with ythe rotor and making sealed contact with said cylinder wall and means for accommodating said impeller means the line of tangency, a balancing rotor coaxial with and connected to said rst rotor-and extending into said discharger chamber and having cppositely directed annular faces and also a surface of revolution, sealingl means to seal' oir from the pressure of liquid in said discharge chamber all of said surface of revolution excepting apor- V tion thereof displaced substantially 180 from the direction of radial thrust exerted upon said first rotor and excepting one of said annular faces. and means for subjecting the other of said an- Y nular-faces to pressure. of liquid in' said inlet said shaft vis subjected to a radial thrust, said:

shaft having operative thereon at a point intermediate of its supports in said bearing means a radial thrust-transmitting means operating in A,

substantially the same pressure as the pressure of liquid in said outlet chamber and exerting a radial thrust upon the shaft in a direction opposed to said first-mentioned radial thrust.

4*. A`pump construction -comprising a casing having a cylinder therein terminating at its resuch that seid rotor is substantially tangential 75 :omen by a cynnder,

ds in an inletchamber and an outlet. a shaft having thereon a rotor of lesser diameter than-said cylinder and extending at its chamber. A

'7. A pump construction comprising a casing having an inlet chamber and an outlet chamber joined by a cylinder, with a' lesser-diametered rotor within the cylinder rotatably mounted to be substantially tangential to the cylinder wall along a line of the latter, said rotor having means comprising va. helical groove in its surface having therein a laminated helical impeller meansof outside diameter equal to the diameter-of said cylinder with theindividual laminations thereof made of substantially rigid material whereby said laminations as a whole are substantially self-accommodating to they surfaces with which they 'engage for substantially sealing contacts of said impeller means with said cylinder wall and with a wall or walls of said'groove, whereby there are exerted upon said rotor an axial thrust and a radial thrust substantially rial leakage of liquid, and means operating upon said rotor and responsive to the pressure dinerential between the liquid in said outlet chamber z louter end'walls of said casing with bearing means and the liquid in said inlet chamber for exerting upon the rotor'axial and radial thrusts respectively opposed to the afore-mentioned axial and radial thrusts.

8A pump construction comprising a casing having an inlet chamber and an outlet chamber with allesser-diametered cylinder wall along a line ofthe latter,

with the rotor.'

as it passes through unimpaired by matewall of said groove. v f 10. A pump construction as claimed in claim 8` rotor within the cylinder rotatably mounted to be substantially tangential to the cylinder wall l along a line of the latter, said rotor having means comprising a helical groove in its surface having therein a laminated helical impeller means of outside diameter equal to the -diameter of said cylinder with the individual laminations thereof made of substantially rigid material whereby said laminations as a whole are substantially self-accommondating to the surfaces with which they engage for substantially sealing contacts of'said impeller means with said cylinder wall and with a wall or walls of said groove, whereby there is exerted upon said rotor a radial thrust substantially unimpaired by material leakage of liquid, means responsive to pressure of liquid in said dis-` charge chamber, and means coacting with said 'pressure-responsivemeans for transmitting force face for contact with the cylinder wall with outer edge faces of successive laminations progressively spaced angularly from one another to thereby form multiple sealing contact with the cylinder v wall, each lamination presenting leading and trailing end edge faces fo'r ing contact with the le making multiple sealding and trailing side in which said individual laminations have lead.- ing and trailing side faces` that extend in respective substantially parallel helical planes of the same pitch as said helical groove and thereby present outer edge faces for multiple sealing contact with the`cylinder wall and said impeller means as a whole is given a flexibility for self accommodation-of its trailing side face for sealing engagement with the trailing side wall of said groove.

11. A pump construction comprising a casing having an inlet chamber and an outlet chamber4 joined by, a cylinder, with a lesser-diametered rotor within the cylinder rotatably mounted to be substantially tangential to a line of the latter, said rotor having a helical groove of substantial depth whereby the side walls of the groove vary in pitch angle according to the radial distance from the axis of the rotor, and

a laminated helical impeller means in said helical groove, said impeller means being of outside diameter equal to the diameter of said cylinder wall and of radial dimension materially greater than the displacement Ibetween the axis of the rotor and the axis of said cylinder, whereby the radial displacement between the axes of said impeller means and of said rotor varies during rotation and engagement and said impeller means partakes of radial movement relative to the groove side walls of varying pitch angle, the individual laminations of said impeller means presenting a plurality oi' surfaces for multi-stage sealing contact and giving the helicalimpeller means substantial self-accommodation to the surfaces with which said impeller means engages and sealing engagement is maintained between the impeller means and the trailing side walls of the helical groove throughout said radial moveof said trailing side wall..

12. A pump constructioncomprising a casing having an inlet chamberand an outlet chamber Joined by'a cylinder, with a lesser-diametered ro- .tor within the cylinder rotatably mounted to be substantially tangential to the cylinder wall along a line of the latter, said rotor having-,a helical groove of substantial depth whereby the side walls of the groove vary in pitch angle according to the radial ,distance from the axis of the rotor, and a laminated helical impeller means of outside diameter equal to the diameter of said cylinthe cylinder wall along der wall and of radial dimension materially greater than the displacement between the -axis of the rotor and the axis of said cylinder, the individual laminations of said impeller means having leading and trailing side faces lying in respective planes that are parallel to each other and extend'at right angles to the axis of the rotor and thereby presenting multiple outer edge faces for multi-stage sealing engagement with said cylinder wall and each lamination having leading and trailing end edge faces for respective multipley engagement with the leading and-trailing side walls of said helical groove, the trailing end edge faces of said laminations having their faces conformed to-a helical plane of the same pitch as said groove and of varying pitch angles lthroughout a range less than but within the limits of the range of change of pitch angles of the-trailing side wall of said helical groove.

- 13. A pump construction comprising a casing n having an inlet chamber and an outlet chamber joined by a cylinder, with'a lesser-diametered rotor within the cylinder rotatably mounted to be substantially tangential to the vcylinder wall along a line of the latter, said rotor having a helical' groove of substantial; depth whereby the side walls of the groove vary in pitch angle according to the radial distance from the axis of therotor, and a laminated helical impeller means of outside diameter equal to the diameter of said cylinder wall and of radial dimension materially greater than the displacement between the axis of the rotor and the axis of saidy cylinder, the individual laminations of said impeller means having leading and trailing end edge `faces forre'- spective contact with the leading and trailing side Walls of said helical groove, with the faces of at least the trailing end edge faces thereof conformed to a, helical plane oi', the same pitch as said helical groove with variable pitch angles `throughout a range less than but within the limits of the rangerof change of pitch angle of the trailing side wall-of said groove.

14. A pump construction comprising a casing having an inlet chamber and an outlet chamber joined by a cylinder, with a lesser-diametered rotor within the cylinder rotatably mounted to be substantially tangential to the cylinder wall along a line of the latter, said rotor having a helical groove of substantial depth whereby the side walls of the groove vary in` pitch angle according to the radial distance lfrom the axis of the rotor. helical impeller means of outside diameter equal to the diameter of said cylinder wall and of radial dimension greater than the ydifference in diame-f ters of said cylinder wall and said rotor whereby said impellermeans projects from the groove in all regions excepting in the region where the rotor and cylinder wallare'substantially tangentialI said helical impeller means being made up of a plurality of individual parts made of a material inherently substantially rigid to thereby give ment therebetween and the varying pitch angle' i 12kl rotor, and a laminated stantially end to end abutting relationship,

the impeller means tion for sealing contact with .at least the variable pitch-angled trailing side wall of said Lgroove throughout the range of radial displacement of `the impeller means relative to said groove.

' K15.. A pumpV construction comprising a casing having an'inlet chamber and an outlet chamber joined by a cylinder, with a lesser-diametered rotor within the cylinder rotatably mounted to be,

j greater than the displacement between the axis of the rotor and the axis of said cylinder, the laminations comprising a plurality of helical ele-l ments made of a material `inherently substantially rigid whereby said helical impeller means -I 2,401,189 substantial selfaccommoda,

walls of the groove vary in pitch angle according to the radial distance from the axis of the rotor, and a laminated helical impeller means of outside diameter equalto the diameter of said cylin- Vder wall and of radial dimension 'materially greater than the displacement between the axis of the rotor and the axis of said cylinder, said ro- Vtor having end faces exposed respectively to said inlet and outlet chambers and having the ends of said helical groovek respectively terminating in said end faces, and means closing off the ends of said helical groove and thereby form abutments tohold the laminated helical impeller against is inherently yieldable for substantial self-accommodation of its trailing side face to sealing engagement,l throughout the varying radial displacements of the impeller means relative to the groove, "with the variablev pitch-angled trailing side face of said helical groove. 16. A pump construction as claimed in claim 15 in which at least one of said helical laminations is sectional.

17. A pump vconstruction as claimed in claim l5 vin which a plurality of said helical laminations vare in sections with successive sections in subthe junctions between sections of successive helical laminations being angularly displaced.

18. A pump construction as claimed in claim l5 provided with means holding said laminations against relative rotary displacement therebetween and means for holding said helical impeller means ata plurality of points throughout its extent against relative rotary displacement between it and said rotor.

19. A pump construction comprising a casing having an inlet chamber and an outlet-chamber joined by a cylinder, with a leSser-diametered rotor within the cylinder rotatably mounted to be substantially tangential to the cylinder wall along a line of the latter, said rotor having a helicaly groove of substantital depth whereby the side endwise emergence from the ends of the groove, said means providing passageway means for the entry therethrough and at the end of the groove adjacent said inlet chamber `of liquid into the variable helical space between the bottom of said helical groove and said helical impeller means and for the exit of liquid from said variable space at the other end of the groove for discharge into said discharge chamber, whereby the liquid is forced along the bottom portions of the groove as the displacement of the laminations relative to the groove progresses from the inlet end to the outlet end. -f

20. A pump construction as claimed in claim 19 in which the'inner edge faces of said laminations that are exposed toward the bottom wall of said groove are conformed to form with the bottom wall of the groove a mouth-like entry for ingress of liquid thereinunder to effect projection thereof outwardly of the groove.

21. A pump construction as claimed in claim 6 inI which the last-mentioned means comprises channel means formed in a wall of said casing and communicating at oneendwith said inlet chamber and at the other end with that portion of said discharge chamber that is sealedoi from the discharge pressure liquid in said discharge chamber.

` tube-like shaft rotatably supporting said rotor and having a passageway therethrough com,- municating at one end with said inlet chamber and at the other end'with that portion of the discharge chamber that is sealed oi vfrom the discharge pressure liquid in said discharge chamber.

FRANCISCO A. QUIROZ

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