US2990782A - Pump device - Google Patents

Description

July 4, 1961 D. L. PHILLIPS I PUMP DEVICE 12 Sheets-Shet 1 Filed July 28, 1955 5 DELBERT 1.. PHILLIPS,

- INVENTOR.

ATTORNEX July 4, 1961 Y D. L. PHILLIPS, 2,990,782

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' PUMP DEVICE Filed July 28, 1955 12 Sheets-Sheet 4 VEN TOR.

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July 4, 1961 D. PHILLIPS 2,990,782

PUMP DEVICE Filed July 28, 1955 12 Sheets-Sheet 5 9 2 in an 5 L I 5 \E s s Q Q:

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D. L. PHILLIPS July 4, 1961 PUMP DEVICE 12 Sheets-Sheet 6 lllllllI I Filed July 28, 1955 DELBERT L. PHILLIPS,

IN VEN TOR.

A T TORNE X July 4, 1961 D. L. PHILLIPS PUMP DEVICE Filed July 28, 1955 12 Sheets-Sheet 7 238 DEL BERT LiNPH/LL/PS,

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D. L. PHILLIPS July 4, 1961 PUMP DEVICE 12 Sheets-Sheet 9 Filed July 28, 1955 hig.2?b.

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July 4, 1961 D. PHILLIPS 2,990,782

PUMP DEVICE Filed July 28, 1955 12 Sheets-Sheet 11 fli gv g4- 248 24a 289 285 Z50 I DELBERT L. PHILLIPS,

INVENTOR.

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July 4, 1961 D. L. PHILLIPS 2,990,782

PUMP DEVICE Filed July 28, 1955 12 Sheets-Sheet 12 DELBERT L. PHILLIPS,

' INVENTOR.

42a 42a 2 ATTORNEY.

United States a w O' Delbert L. Phillips,

This invention relates to a rotary device for use either as a pump or fluid motor, which device is of the general character comprising a casing having input and output ports, a rotor cooperating with the casing to form an annular or ring-shaped chamber having two spaced walls, a blade unitary with the rotor and of undulating configuration for wiping contact with the two spaced walls, and a reciprocative abutment in sealing engagement with the undulating blade from opposite sides thereof to divide the annular chamber into expanding input compartments and contracting output compartments. In one type of the invention to be described hereafter, the undulating blade extends radially from the rotor. Devices of this type are disclosed, for example, in the Whitney Patent 167,374, issued August 31, 1875, and in the Bourgeois Patent 732,547, issued in France. In a second type of the invention, described later, the undulating blade extends axially from the rotor.

The present application is a continuation-in-part of my copending application entitled Positive Displacement Pump, Ser. No. 391,104, filed November 9., 1953, and now abandoned. Broadly described, the invention is directed to the general problem of increasing the efiiciency of such a device as well as to more specific problems relating to scaling of cooperative surfaces, reduction of friction, reduction of Wear by abrasive particles, automatic compensation for wear, minimizing of stressing of structural components, the attainment of a long service life with sustained efiiciency and with minimum attention and maintenance, the attainment of high magnitude displacement per unit rotation of the rotor for high volumetric capacity at relatively low operating speeds, the minimizing of turbulence and velocity changes in the handling of fluids, and the provision of what may be termed multiple devices of this character. As will be explained, such multiple devices have multiple-undulation rotor blades to operate with multiple fluid cycles concurrently and may be designed primarily to increase the rate of volumetric displacement of a rotary device of a given size or primarily either to cause proportionate flow to the device from multiple fluid sources or to cause proportionate flow from the device to multiple distribution points. It will be apparent to those skilled in the art that while all of these features may be incorporated in a single device and preferably substantially all of them are so incorporated, nevertheless, the features may also be incorporated individually and in various groupings as may be desired. 7

One of the more important features of the invention is directed to the problem of sealing the juncture of the reciprocative abutment with the two faces of the undulating rotor blade. This problem presents difi'iculties because the angle of the 'blade relative to the reciprocative abutment varies widely. The angle is 90 at one position of the blade relative to the abutment and varies to a departure in both directions from this central angle. It is desirable that these maximum departures from the 90 angle be of relatively large magnitude because the volumetric displacement of the rotary device depends ments heretofore used in the art have been efiective only over a few degrees of departure from the intermediate 90 angle and consequently prior art rotary devices of this type have provided limited volumetric displacement per unit of rotation. I

on these magnitudes. Sealing arrangethatis efiective at an angle 45 from the angle and to which the eiiective volume of will tighten under pressure to run in a smooth 2,990,782 Patented July 4, 1961 The limiting efiect may be appreciated with respect to the first type of the invention when it is considered that the circumferential pitch or helical inclination of a radially extending undulating blade relative to its plane of rotation varies radially of the blade, the pitch being greatest at the hub or root of the blade and least at the outer circumference or periphery of the blade. .The pitch also varies, of course, circumierentially, being substantially zero where the blade undulations wipe theend walls of the chamber and being greatest in the region midway of the end wall of the chamber. It is apparent, then that the point of maximum pitch of such an undulating blade is at the hub or root of the blade in the mid-region of the annular chamber.

One method of dealing with this limitation in the first type of the invention is to use a rotor having a hub of relatively large diameter to increase the ratio between the root or inner diameter and the periphery or outer diameter of the blade. The disclosure of the above Whitney patent is an example of this approach and it shows how the consequent relatively largev dead space in the axial region of the device reduces the volumetric displacement. v

The alternate method of dealing with this limitation in the first type of the invention is to make thepump relatively thin in axial dimension thereby to reduce the pitch angle in the region of maximum pitch midway be; tween the end walls of the pump. The disclosure of the above French patent is an example of this second approach and shows how this second solution reduces the capacity of the pump by limiting the axial dimension.

The present invention provides a sealing arrangement of departure as large as thus permits the pitch to vary 45 in both directions from the plane of rotation of the rotor to permit a total range of 90 of pitch variation. Thus the invention permits the pitch at the maximum point, namely, at the root of the blade in the mid-region of the chamber, to' be as great as 45 relative to the plane of rotation of the rotor. This liberal maximum blade pitch afiorded by the sealing arrangement of the invention, makes possible increasing both the radial dimension and the axial dimension of the annular chamber for greater volumetric displacement. It is to be noted, moreover, that the increase inaxial dimension of the annular chamber reduces the degree the chamber is diminished by the presence. of the rotor blade. As a' result of these volumetric advantages, a device of this character of a given size may have an annular'chamber nearly four times the capacity afforded by prior art devices. The increase in axial dimension of the annular chamber is important when the device is used as a fluid motor since the area eifective for pressure response varies in accord with this axial dimension.

. Broadly described, the desired sealing action throughout a wide range of angles in both types of the invention is afforded by providing a reciprocative abutment with spaced edges of rounded cross-sectional configuration and by varying the thickness of the rotor blade in accord with its changes in pitch to maintain constant contact with both of the rounded edges. In the preferred practices of the invention, the rounded edges are provided by rotary sealing elements that are floatingly mounted on the reciprocative abutment for sealing action in response to fluid pressure. This arrangement not only provides an automatic sealing action but also provides automatic compensation for wear. In fact, a badly worn device constructed in accord with the present invention and efiicient manner. 1

Reduction of wear and friction resistance are efiected panding compartments in various ways. One important fact in this regard is that the increased volumetric displacement of the de vice makes it possible for a given volume of fluid to pass through the device in a unit of time at a lower speed of rotary operation of the device than heretofore possible and, of course, reduction in speed of operation means reduction of wear. 'In the preferred practice of the invention, wear and friction are minimized by using a pivoted arcuate reciprocative abutment so that guidance for the reciprocative movement of the abutment is provided solely by a pivot bearing. No guiding pressure is required between the reciprocative abutment and the undulating rotor blade. In some practices of the invention wear and friction are also reduced by using plastic materials to provide low coeflicients of friction. Thus the undulating rotor blade and also the reciprocative abutment may be made of such plastic material or at least have a plastic surface; and plastic material may also be used to line the end walls of the chamber. For operation at relatively high temperatures, such plastic materials as Teflon and Kel-F may be used but for operation at lower temperatures and pressure, nylon is presently preferred.

it has been found, moreover, that nylon will recover from depressions made therein by foreign particles. The invention further teaches that wear and damage by foreign particles may be minimized by providing special particle-receiving recesses in the walls of the annular chamber in the outflow region adjacent the reciprocative abutment. As the rotor blade wipes the walls of the annular chamber and sweeps the particles towards the reciprocative abutment, the particles are pushed into the recesses instead of being trapped by the closing action of the blade and abutment.

In the preferred practice of the invention, the particlereceiving recesses communicate with the output port of the device so that particles delivered to the recesses are continually flushed out of the recesses to the output port.

The minimizing of turbulence and velocity changes as aflorded by the invention is especially important in pumping of fluids that foam easily. This feature is also important for minimizing cavitation and flashing in the pumping of volatile fluids. Since the rotor in the present device rotates at a relatively slow speed for a given rate of fluid flow and since fluid will flow through the device in a pulsation-free manner, the invention is inherently advantageous for use with such fluids.

With reference to the possibility of either type of the invention operating with multiple concurrent fluid cycles, this possibility may be understood when the effect of multiple undulations of the rotor blade is considered. A rotor blade that has only a single pair of portions spaced 180 apart in wiping contact with the two opposite walls of the annular chamber may be termed a single-undulation blade. A single reciprocative abutment cooperates with the single-undulation blade to form repeatedly two expanding compartments and two contracting compartments. A two-undulation blade in cooperation with two reciprocative abutments positioned circumferentially 180 apart repeatedly forms four exand four contracting compartments.

Increasing the number of undulations and correspondingly increasing the number of reciprocative abutments correspondingly increases the fluid displacement per rotation of the rotor blade. Thus doubling the number of undulations and reciprocative abutments substantially doubles the volumetric capacity of the device without change in dimension of the annular chamber. Heretofore it has not been feasible to use a rotor blade having multiple undulations in the first type of the invention because increase in the number of undulations of a rotor blade for operation in a chamber of a given size necessarily means corresponding increase in the maximum pitch of the undulations and prior art devices of this character have not permitted high pitch angles.

It is apparent that the precise configuration of the radial undulating rotor blade in the first type of the invention is quite complicated, not only because its undulation curvature is complex, but also because its thickn'ess varies both circumferentially and radially. In this regard, the preferred practice of the invention is further characterized by a method of arriving at the complicated rotor blade configuration, which method is relatively simple and at the same time exceedingly accurate.

In general, the method of shaping the rotor blade for either type of the invention is characterized by the use of a material-removing element such as an end mill to remove material from a rotor blank, the material-removing element having the same rounded configuration as the rounded slot edges of the abutment member in the rotary device. The material-removing element is advanced laterally against the rotor blank with the blank rotating about its axis and with the material-removing element shifting relative to the rotating blank in the same manner that a rounded edge of the reciprocative abutment shifts relative to the rotor blade in the operation of the intended device. In this manner, each face of the rotor blade is accurately shaped for maintaining constant contact with the corresponding rounded sealing edge of the reciprocative abutment.

The preferred practice of the invention is further characterized by the provision of a relatively simple appar'atus to carry out this process for accurately shaping the rotor blank. Such an apparatus that provides for rotation of a rotor blank and for synchronous advancement of a material-removing element may be designed for flexible use to shape rotors of various dimensions with various numbers of peripheral undulations.

The various features and advantages of the invention may be understood from the following detailed description considered with the accompanying drawings.

-In the drawings, which are to be regarded as merely illustrative:

FIGURE 1 is a perspective view of a selected embodiment of the invention that may be used either as a pump or as a fluid motor;

FIGURE 2 is a longitudinal sectional view taken as indicated by the line 22 of FIGURE 1;

FIGURE 3 is a transverse sectional view taken as indicated by the line 3-3 of FIGURE 2;

FIGURE 4 is a view of the device with a cover removed, the view being taken as indicated by the line 4-4 of FIGURE 2;

FIGURE 5 is an exploded perspective view showing basic working parts of the device;

FIGURE 6 is a diagrammatic view on a large scale showing how the reciprocative abutment cooperates with the undulating rotor blade;

FIGURE 7 is a similar but fragmentary view showing two different positions of the reciprocative abutment relative to the undulating blade;

FIGURE 8 is a fragmentary section taken as indicated by the line 8-8 of FIGURE 6 and showing how a sealing shoe cooperates with the reciprocative abutment;

FIGURE 9 is a fragmentary sectional view on an enlarged scale taken as indicated by the line 99 of FIG- URE 6 and showing how rotary sealing elements carried by the reciprocative abutment cooperate with the undulating rotary blade;

FIGURE 10a is a diagram showing the relation of the reciprocative abutment with the peripheral or outer circumferential portion of the undulating blade at various circumferential stations;

FIGURE 10b is a similar diagram showing the relation of the reciprocative abutment with the root portion of the undulating rotary blade;

FIGURES 11, 12, and 13 show the cross-sectional configuration ofth undulating rotary blade at difierent circumferential stations; 1

FIGURE 14 is a simplified diagrammatic perspective .view of an apparatus that may be employed to shape the undulating rotor blade;

FIGURE 14a is a section taken as indicated by the line 14a-14a of FIGURE 14 showing one end of a Scotch-yoke member;

FIGURE 15 is an enlarged transverse section taken as indicated by the line 15-15 of FIGURE 14 and showing how the apparatus of FIGURE 14 may be adjusted to compensate for the thickness of the rotor blade;

FIGURES 16a and 16b are diagrams indicating the paths of movement of the rotary cutting element of FIG- URE 14 as required for shaping the opposite faces of the undulating rotor blade;

FIGURE 17 is a view similar to FIGURE 4 showing a second embodiment of the invention in which a flat abutment instead of an arcuate abutment reciprocates in a linear manner instead of in an arcuate manner;

FIGURE 18 is a fragmentary longitudinal section taken as indicated by the line 18-18 of FIGURE 17;

FIGURE 19 is a fragmentary diagrammatic view showing how the apparatus illustrated'in FIGURE 14 may be modified to shape the undulating rotor blade employed in this second embodiment of the invention;

' FIGURE 20 is a transverse sectional viewof a third embodiment of the invention that may serve either as a multiple pump or as a multiple fluid motor, the device having a rotor blade with multiple peripheral undulations, the section being taken as indicated by the line 20-20 of FIGURE 21;

FIGURE 21 is a view of the third embodiment of the invention with a cover removed, the view being taken as seen along the line 21-21 of FIGURE 20;

FIGURE 22 is a sectional view taken as indicated by the'line 22-22 of FIGURE 20;

FIGURE 23 is a fragmentary transverse sectional view taken as indicated by the line 23-23 of FIGURE 21; FIGURE 24 is a transverse sectional view taken as indicated by the lines 24-24 of FIGURES 21 and 22; FIGURE 25 is a sectional view of a casing member taken as indicated by the line 25-25 of FIGURE 24;

FIGURE 2.6 is an elevational view of the multipleundulation rotor employed in the third embodiment of the invention;

FIGURE 27a is a view similar to FIGURE a showing the relation of the reciprocative abutment of the third embodiment of the invention with the peripheral portion of the undulating blade;

FIGURE 27b is a view similar to FIGURE 10b showing the cooperation of the abutment member with the root portion of the undulating blade and;

FIGURE 28 is a'diagram showing how a multiple pump similar to the third embodiment of the invention may be used to transfer fluid from two separate sources to two corresponding separate distribution points;

FIGURE 29 is an elevational view of an embodiment of the second type of the invention wherein the rotor blade extends in a direction axially of the rotor, the view 'being taken with a cover plate removed;

FIGURE 30 is a diametrical sectional view taken as indicated by the line 30-30 of FIGURE 29; 7

FIGURE 31 is a fragmentary sectional view taken as indicated by the line 31-31 of FIGURE 29 to show the construction of the reciprocative abutment;

FIGURE 32 is a transverse section taken as indicated by the line 32-32 of FIGURE 29 showing the two ports of the device;

FIGURE 33 is a view similar to FIGURE 29 showing another embodiment of the second type of the invention in which the rotor blade extends in an axial direction of the rotor; and 1 FIGURE 34 is a view, partly in section and partly in .side elevation, showing how spring may be erably the portions of the abutment added for cooperation with a reciprocative abutment in some practices of the invention. v

' The first emb diment of the first type of the invention illustrated by FIGURES 1 to 9 has an annular or ringshaped pump chamber, generally designated by numeral 30, which is defined by a cylindrical wall 32, two spaced end walls 34 and 35 and the hub 36 of a rotor that is generally designated by numeral 38.- The rotor 38 has a radially extending blade 40 and is mounted on a suitable shaft 42. I i

The blade 40 is of undulating circumferential configuration shaped and dimensioned to wipe the two end walls 34 and 35 and may be termed a single-undulation blade since only one portion of the blade makes wiping "contact with each of the two end walls, these two wiping portions being spaced circumferentially .apart. A reciprocative abutment, generally designated by numeral 44, spans a radial portion of the annular chamber 30 in a generally axial direction in sealing contact with the two faces of the undulating blade 40 and thus cooperates with the rotating blade to divide the annular chamber into expanding input compartments and contracting output compartments. Throughout most of the range of rotation of the rotor, one side of the reciprocative abutment "cooperates with the undulating rotor blade 40 to form two expanding compartments and the other side cooperates to form two contracting compartments. When either of the two wiping portions of the blade 48 is at the reciprocative abutment 44, however, there is momentarily only one expanding compartment on one side of the abutmentand only one contracting compartment on the other side of the abutment. With the rotor rotating at a constant rate, the various compartments expand and contract at a constant rate for substantially non-pulsating fluid flow through the device.

Preferably the reciprocative abutment 44 is of curved configuration to reciprocate along a curved path and prefmember that engage the opposite faces of the rotor blade 40 are integral with each other, the abutment member being formed with a slot to receive the rotor blade. It is to be understood, however, that the reciprocating abutment 44 need not be curved and the two portions thereof on the opposite sides ofthe rotor blade need not be integral with each other.

As best shown in FIGURE 5, the abutment member 44 in the preferred practice of the invention has an arcuate abutment wall 45 with a slot 46 therein to receive the rotor blade 40 and is formed with a tubular bearing portion 48 that isintegrally united withthe arcuate abutment wall by a pair of radial arms 50. The tubular bearing portion 48 which is concentric to the axis of curvature of the abutment wall 45 is rotatable on a suitable pivot pin 52 that is mounted in a blind bore 54 of the casing, a counter-bore 55 being provided to accommodate the tubular bearing portion. Preferably the tubular bearing portion 48 of the reciprocative abutment 44 is provided with a pair of bearing sleeves 56 (FIGURE 3) of suitable material to minimize-frictional resistance of the reciprocative abutment on the bearing pin 52. These bearing sleeves 56 may, for example, be made of nylon.

It is contemplated that the slot 46 of the reciprocative abutment member 44 will provide two spaced edges of curved cross-sectional configuration in sealing contact with the rotor blade 40. While such curved edges may be integral parts of the reciprocative abutment member, a feature of the preferred practice of the invention is the use of rotary sealing elements to provide the desired curved surfaces. As best shown in FIGURE 9, each side of the slot of the reciprocative abutment member may be provided with four cylindrical sealing elements 58 mounted in longitudinal alignment on a retaining pin 60 carried by the abutment. The cylindrical sealing elements 58' are floatingly mounted on the reciprocative abutment 44 in the sense that they fit sufliciently loosely onthe two pins 60 for freedom for lateral movement rel aend wall'35 of the annular chamber.

. tive to the pin and the abutment member is cut awa -er recessed to permit such freedom. Preferably the reciprocative abutment is formed 'w-ith cylindrically curved recesses "62 as shown in FIGURES 6 and 7 which partially enclose thesealin'g elements 58 and these recesses are slightly oversized with respect to the outside diameter of the sealing elements 58.

The advantage of this arrangement is that when fluid pressure is directed against one side of the arcuate abutment wall 45 as indicated by the arrows 64 in FIGURE'6, the cylindrical sealing elements 58 are free to respond to the pressure by moving into what may be termed wedging contact with both the walls of the recesses 62 and the two faces of the rotor blade 40. The use of a plurality of longitudinallyaligned rotary scaling elements 58 instead ofsingle rotary sealing elements on each side of the blade is advantageous inasmuch as the rate of travel of the two faces of the 'rotor blade 40 increases with the radial distance of the axis from the rotor. While the cylindrical sealing elements 58 may be made of any suitablematerial, nylon is preferred.

Any suitable casing construction may be used for the "rotarydevice. In the present construction, as best shown in FIGURE 5, the casing may comprise a main casing section, generally designated 65, a cover member 66, and a cup-shaped casing end section -68 together with a retain- "ing plate 70 that is best shown in FIGURES l and -2.

The main casing section 65 is formed with four bosses 72 (FIGURES land 2) to serve as legs and is also "formed with four bosses 74 to receive cap screws 75 for the retaining plate 70. The main casing section 65 pro- "videsthe previously mentioned cylindrical wall 32 and the previously mentioned end wall 34 of the annular chamber and provides an oval opening 76 to the annular chamber.

The cup-shaped end section 68 of the casing telescopes into the cylindrical wall 32 of the main casing section 65 as best shown in FIGURE 2, and is sealed by an O-ring 78. This end section of the casing provides the second A stud 80 threaded into the cylindrical wall 32 extends into a blind bore 82 of the end section '68 of the casing as shown in FIGURE 2 to maintain the end section at a desired rotary position 'relative to the main casing section 65. The retaining plate 70 which has a central opening 84 to clear the shaft 42 abuts the outer end of the endcasing section 68 to hold the end casing section in position in opposition to 'fluid'p'ressure.

As shown in FIGURE 2, the rotor 38 has a trunnion '85 that extends through an aperture 86 in the end wall 35 and has a second trunnion '88 that is journalled in a bearing sleeve 90 in a blind bore 92 in the end wall 34. The cup-shaped-end section 68 of the casing has an axial tubular portion 94 in which is mounted a suitable ball bearing 95 for the shaft 42. The outer race of the ball bearing abuts a split retainer ring 96 and also abuts a sealing collar 98 which confines an O-ring 100 in a circumfer'ential groove 102 in the shaft 42.

The arcuate wall 45 of the reciprocative abutment 44 oscillates longitudinally in an arcuate space or way 104, the oppositeends of which are interconnected by an angular fluid passage 105 to keep fluid from being trapped therein.

The arcuate way 104 and the angular fluid passage 105 are formed in part by the main casing section 65 and in part by the end section 68 of the casing. For this purpose, as may be seen in FIGURE 5, the end section 68 of the casing has a slot 106 in the end wall 35 thereof andadditionally has a partition wall 108 defining a space in communication with the slot. The two radial arms 50 of the reciprocative abutment move in a shallow space between the "cover member 66 and a flat surface 110 (FIGURE provided by the main casing section 65.

The coverinember 66, which is'sealed by an 0-ring "109 is'h'eld in place-by screws-1'12-threaded into-bosses 114 of the main casin'g se'etioh65 and'provides t'wo ports 115 and 116 separated by a dividing wall 118. As best shown in FIGURE 2, an adapter 120 may be mounted on the cover member 66 by means of cap screws 122 to adapt the device for connection to threaded pipe. The adapter 120 has threaded ports 124 and 125 to register with the ports 115 and 116, the two threaded ports being separated by a dividing wall 126. Suitable O-rings 128 seal the juncture between the adapter 120 and the cover member 66 around the two threaded ports.

It is essential that suitable sealing rings be provided to keep fluid from passing around the edges of the reciprocative abutment 44. p In this regard it is to be noted that the lower edge of the abutment is in tangential sealing contact with the cylindrical surface of the rotor hub 36 to keep fluid from passing under the abutment. To 'keep fluid from passing over the abutment, a sealing element 130 of suitable material such as nylon is seated in a groove 132 in sliding contact with the upper edge of the arcuate abutment wall 45.

To keep the fluid from moving from one face of the abutment blade 44 to the other face around the opposite ends of the abutment blade, suitable sealing elements 134 may be mounted in recesses '135 in the casing adjacent the arcuate way 104, there being one such sealing element in a recess on each side of the oval chamber opening 76. As best shown in FIGURES 6, 7, and 8, each of the sealing elements 134 may be of half-round cross-sectional configuration-and may be maintained under constant pressure against the reciprocative abutment 44 by means of a leaf spring 136. As shown in FIGURE 8, the previously mentioned sealing element 130 at the top edge of the arcuate abutment wall 45 is in contact with the ends of both of the sealing elements 134. It is important to note that since the reciprocation of the abutment 44 is pivotallyguided by the pivot pins 52, none of the sealing elements associated with the reciprocative abutment is burdened with a guiding function and none is subject to guiding pressure in addition to fluid pressure.

While the rotor 38 may be made of various materials, for withstanding high temperature and pressures, preferably the rotor as constructed for use at moderate temperatures and pressures is at least partly made of a suitable plastic that will afford a low-coeflicient of friction. For example, the rotor may be made entirely of a plastic such as nylon.

In the present embodiment of the invention, the rotor 38 and its undulating blade 40 are of combined plastic and metal construction, as best shown in FIGURE 2, the rotor and blade being in the form of an investment casting with a steel core 138. The steel core 138 is undersized with respect to the outside dimensions desired for the rotor and preferably is formed with numerous a'pertures 140 in its blade portion. This steel core is'covered with a plastic sheath 142 of nylon or other suitable plastic material with the opposite faces of the plastic sheath interconnected through the apertures 140, as indicated in FIGURE 2. The plastic sheath 142 may extend over the hub 36 of the rotor and may additionally extend over the circumferential surfaces of the rotor trunnions 85 and 88. It is apparent that the plastic sheath 142 materially reduces the frictional resistance of rotation of the rotor and that the metal core 138 lends rigidity and thermal stability to the rotor.

The preferred practice of the invention is further characterized by the addition of plastic sheet liners 144 for the two end walls 34 and 35 of the annular chamber. These liners may be made of nylon. Preferably the plastic liners 144 are formed with circumferential lips '145 as shown in FIGURE 2 and the circumferential edge of the rotor blade 40 is shaped with bevels 146 to conform to the circumferential lips. Nylon is advantageous both for the sheath 142 of the rotor and for the end liners 1440f the annular chamber. -Nylon is especially advantageous bethin at maximum pitch angle.

cause it has been found that nylon tends to recover from indentations made therein by hard foreign particles.

With reference to handling fluids with solid particles entrained therein, the preferred practice of the invention provides recesses into which such particles may be swept by the rotor blade instead of being trapped by the blade. For this purpose, the two end walls of the chamber may be cut away adjacent the reciprocative abutment on the output side thereof. Thus if the rotor rotates counterclockwise as viewed in the drawings to make port 116 the output port, the two end walls may be cut away to provide particle receiving recesses 147, as shown in FIG- URES and 6. These recesses communicate directly with the output port and are continually flushedby the outgoing fluid.

Since the rotor blade 40 is of generally helical configuration, the blade may be described as having pitch angle relative to its plane of rotation. In this instance, however, the pitch of the blade varies around the circumference of the blade and also varies radially of the blade. These variations in pitch may be understood by references to the diagrammatical representation of the rotorblade in FIGURES 6, a, and 10b.

As shown in FIGURE 6, the blade 40 has two diametrically opposite portions 148 shaped and positioned for Wiping contact with the two end walls 34 and'35 of the annular chamber 30, these two opposite portions being in generally tangential relation to the two end walls 34 and 35. The two opposite portions 148 of the rotor blade are of substantially Zero pitch since they are in planes substantially perpendicular to the axis of the rotor 38, i.e. are aligned with the plane of rotation of the rotor. The pitch angle of the rotor blade varies around the circumference between the opposite portions 148 sinusoidally or approximately in the manner of a sine curve, the pitch angle progressively increasing from each of the end walls of the chamber to the middle of the chamber. Thus in FIGURE 6, the sealing elements 58 of the reciprocative abutment 44 are shown in contact with the rotor blade 40 in the central region of maximum blade pitch, there being two such regions spaced 180 apart circumferentially. The fact that the root portion of inner diameter of the rotor blade 40 varies through a greater pitch angle than the peripheral portion may be seen in FIGURE 6 where the two curved broken lines 150 represent the thickness pitch angle is maximum in the region midway between the two diametrically opposite wiping portions 148 and since the pitch angle of the root portion of the blade exceeds the pitch angle of the peripheral portion, the point of maximum pitch angle for the whole blade is in this root region, there being two such root regions 180 apart.

These facts regarding pitch angle are shown diagrammatically in FIGURE 10a representing the peripheral portion of the blade and in FIGURE 10b representing the root portion of the blade. The two opposite wiping portions 148 are shown at the 0 station and at the 180 station and the intermediate portions of the blade of maximum pitch angle are shown at the 90 and 270 stations.

As hereto-fore stated, an important feature of the invention is the concept of so varying the thickness of the rotor blade 40 as to cause the two opposite faces ofthe rotor blade to maintain constant contact with the curved edges of the slot 46 of the reciprocative abutment 44. Since the curved edges of the slot provided by the two rows of rotary sealing elements 58 are fixed in spacing relative to each other, the thickness of the blade must, in general, vary inversely as the pitch angle of the blade, being relatively thick at zero pitch angle and relatively While this relationship holds true for FIGURE 101 which represents the periphery of the rotor blade, it is more readily apparent in FIG- URE 10b which represents the root of the blade. Thus in FIGURE 10b the blade is of maximum thickness where -.the rotor blade is of minimum pitch angle =at'the 0 and of the root portion of the rotor blade. Here again, the

180 stations and is of minimum thickness in the region of the 90 and 270 stations.

It is to be noted, however, that the controlling factor is the angle of the rotor blade 40 relative to the reciprocative abutment 44 at the abutment slot. Since the reciprocative abutment is curved and moves in a curved path, the points of maximum blade thickness are slightly displaced from the 0 and 180 stations and the points of minimum blade thickness are, in like manner, slightly displaced from the 90 and 270 stations, as may be seen in FIGURE 10b.

These facts with regard to the varying thickness of the blade for maintaining constant contact with the slot edges of the reciprocative abutment member mean that the blade is thinner at its root portions than at its peripheral portions, as may be seen in FIGURES 11, 12, and 13, which show the radial cross-sectional configuration of the blade 40 at the four stations. It will be noted in FIGURE 12 that the rotor blade narrows markedly towards the hub 36 at the 90 and 270 stations.

It is also to be noted in FIGURES 11 to 13 that the radially inwand taper of the rotor blade is of slightly curved configuration and that this inward curvature occurs also at the 0 and 180 stations as may be seen at 152 in FIG- URES 11 and 13. This inward curvature is required because the slot of the reciprocative abutment moves in an arcuate path. This arcuate path is represented by the curved line 154 in FIGURE 6. It will be noted that the midpoint of the curved line 154 lies on one side of the radial plane 155 through the axis of the rotor and that the two opposite ends of the curved line lie on the other side of this axial plane. It is this departure of the curved path 154 from the plane 155 that requires the curvular tapering cross-sectional configuration of the rotor blade shown in FIGURES 11, 12, and 13. For the same reason,

at the points on the curved path 154 of maximum departure from the plane 155, i.e. at the 0 and 180 stations and again at the 90 and 270 stations, the two series of rotary cylindrical sealing elements 58 of the reciprocative abutment make contact with the rotor blade 40 along lines that curve slightly around the circumferences of the sealing elements rather than along straight lines parallel to the axes of the elements.

The advantages of the invention may be appreciated by considering the described embodiment as operating for pump-ing a fluid which may be either gaseous or liquid. The large volumetric displacement per revolution of the rotor makes it possible to use a relatively small and light pump for a relatively high rate of flow. The large'volumetric displacement also makes it possible to achieve a relatively low frequency of expansion and contraction for a given rate of flow. The reduced abruptness in the contraction and expansion of the input and output compartments of the pump reduces flashing, frothing, and cavitation in the pumping of various liquids, especially volatile liquids. In this regard, it is to be noted that the radial cross-section of the pump chamber is approximately a square and thus does not depart radically from the circular cross-sectional configuration of the pump ports and the piping connected thereto. Thus the changes in crosssectional configuration of the fluid stream passing into, through, and out of the pump are minimized and this fact also tends to reduce flashing, frothing, and cavitation. The large volumetric displacement per revolution also makes it possible to design a pump of a given size for relatively slow rotation for a given flow rate with relatively low stressing of the component parts of the pump and with avoidance of concentrated high magnitude friction.

A number of factors work together to result in a long service life for such a pump with minimum attention and maintenance. Among these factors are: the relatively slow rate of rotation for a given rate of flow; the low stressing of structural components; the use of rotary sealing means made in sections to reduce drag friction; the automaticcompensation for wear by floatingly mounted sealing elements; the use of low-friction plastic materials 1 1 for sealing action; the low vulnerability of plastic material such as nylon to damage by grit particles; the rigidity of acne-piece curved abutment member; the use of pivotal guidance for the reciprocative abutment member to avoid guiding loads on the surface of the abutment member and on the surfaces of sealing elements associated therewith; and the use of a sine-curved rotor blade to result in harmonic motion on the part of the reciprocating abutment wit-h consequent minimum shock and minimum fatigue with reference both to the abutment and the rotor blade.

The device will operate as a pump with a thermal efficiency of 90 to 95 percent. The fact that such a pump of a relatively small size will operate at a high rate of flow with arelatively low speed of rotation may be appreciated by a comparison with a conventional gear type pump. In one instance, for example, a pump constructed as heretofore described and of a size to weigh only three and a :half'pounds replaced a larger gear pump of a size weighing eighteen pounds. The smaller pump handled fluid at the same rate as the larger pump but operated at 1000 r.p.m. instead of 4500 r.p.m. as required in the operation of the larger pump. The invention embodied as a fluid motor may be compared advantageously in the same manner with fluid motors of conventional types.

It is apparent from the foregoing discussion that since the thickness of the rotor blade 40 varies continuously circumferentially as well as radially and has surfaces that are curved radially as well as circumferentially, the rotor blade is of a complicated configuration, the configuration being especially complicated since allowance must be made for the arcuate path of movement of the reciprocative abutment 44. In this regard a feature of the invention is a highly accurate method of arriving at a precise configuration for a rotor blade 40 as well as for arriving at the configuration of a metal core 138 for a rotor blade.

Broadly described, this method comprises removing material from a rotor blank by means of a material-removing element that is of the same rounded configuration as the rounded edges of the slot 46 of the reciprocative abutment. The method includes the steps of rotating the rotor blank about its axis and of advancing the materialremoving element against the blank along a path relative to the rotating blank that corresponds to the path of a curved slot edge relative to the rotor as intended in the operating device. While such a method may be carried out by hand, it may be practiced in a highly advantageous manner by means of an apparatus such as shown in FIGURES 14, 14a and 15.

The apparatus which is shown in a simplified and diagrammatic manner in FIGURE 14 includes a headstock 156 and a tailstock 158 to hold a blank or workpiece 160 in the usual rotary manner for the removal of material therefrom. The headstock and tailstock are mounted on a common bed plate 162 that slides in a way 164 in a fixed base 165 and is controlled by a screw '166. The screw 166 is threaded into an upward projection 168 of the base and is manually operable by a hand crank 170. For rotation of the workpiece or blank 160 in a well known manner the headstock 156 has an axial drive shaft 172. The shaft 172 may be provided with a drive sheave 174 that is actuated by a V-belt 175 from "a suitable power source.

The apparatus holds and operates a material-removing element 176 which preferably is a rotary tool in the form of an end mill. For shaping the rotor 38 of the above described embodiment of the invention, the end mill 176 is of the same diameter as the previously described rotary sealing element 58. Any suitable arrangement may be provided to actuate the end mill 176 and to advance the end mill against the blank 160 in the required synchro- 'nization with the rotation of the blank by the headstock 156.

In the arrangement shown in FIGURE 14 a support "yok'e 178 having parallel horizontal arms 180 is mounted on suit-ablesupport structure (not-shown) and is verticali7 12 Iy adjustable by a screw 182. The screw 182 is threaded through a fixed member 184 and is manually rotatable by a hand crank 185.

Iournalled in the outer ends of the two yoke arms is a driven shaft 186 which is provided with a driven sheave 188 and a gear 190. The driven sheave 188 is connected by a V-belt 192 by a drive sheave 194 on a vertical drive shaft 195. The drive sheave 194 is slidable along the drive shaft 195 in engagement with extensive splines 196 so that it may be adjusted on the drive shaft in accord with various levels of adjustment of the support yoke 178.

Hingedly mounted on the driven shaft 186 is a spindle housing 198 in which is journalled an upright shaft 200 for rotating the end mill 176, the end mill being releasably connected with this upright shaft in a well known manner. A gear 202 on the upright shaft 200 is in mesh with the previously mentioned gear for actuation of the upright shaft. By virtue of this arrangement the gear 202 may be moved in a planetary manner relative to the gear 190 for operative engagement therewith throughout the arcuate range of binge movement of the spindle housing 198 about the axis of the driven shaft 186.

Midway between the two arms 180 of the support yoke 178, the spindle housing 198 is reduced in cross-sectional dimension to form a cylindrical neck 204 of relatively small diameter as shown in FIGURE 14a. The neck 204 is surrounded by a larger ring 205 which is integral with and extends upward from an arm 206 in the form of a heavy plate, this arm being rotatably mounted on the previously mentioned driven shaft 186. Thus the ring 205 and the neck 204 of the spindle housing both pivot about the axis of the upright shaft 200 with the axis of the ring and the axis of the neck at the same radial distance from the axis of the driven shaft. The purpose of this arrangement is to permit the neck 204 of the spindle housing 198 to be shifted between two alternate positions inside the ring 205 to allow for the thickness of the rotor blade. For the purpose of positioning the spindle housing 198 at the two alternate positions relative to the ring 205, the ring has two threaded bores 208 and 210 in which a suitable set screw 212 may be threaded alternately to crowd the spindle housing neck 204 against one or the other side of the ring. Thus in FIGURE 15, the set screw 212 is threaded into the bore 208 to hold the spindle housing neck 204 firmly against the opposite side of the ring.

In the present embodiment of the apparatus, the spindle housing 198 is moved along its arcuate path by an actuator in the form of a Scotch-yoke member 214 that operatively engages the ring 205. As shown in FIGURE 14a the Scotch-yoke member has an elongated opening or slot 215 with parallel edges in snug sliding engagement with the periphery of the ring 205.

The Scotch-yoke member 214 is mounted for longitudinal sliding movement in a suitably supported guide sleeve 216 and is shaped at its second end to provide a second slot 218 that is parallel to the first slot 215. The second slot 218 is in snug sliding fit with a crank pin 220 that extends upward from a disc 222 on a vertical driven shaft 224.

The vertical driven shaft 224 is actuated in any suitable manner in synchronism with the axial shaft 172 of the headstock 156, so that a single rotation of the disc 222 occurs simultaneously with a single rotation of the rotor blank 160. For this purpose a gear 225 on the headstock shaft 172 may mesh with an idler gear 226 which meshes in turn with a third gear 228. The third gear 228 is on a counter-shaft 230 that carries a bevel gear 232 in mesh with a bevel gear 234 on the vertical driven shaft 224.

The manner in which the described apparatus serves its purpose is apparent from the fact that the arcuate path of the end mill 176 corresponds in position and curvature of sufficient diameter to bore 210 to force the neck 204 of the spindle 13 to the arcuate path of a rounded edge of the slot of the previously described reciprocative abutment 44 of the rotary device. The movement of the end mill along its path is synchronizedwith the rotation of the headstock shaft 156 in the same manner as the movement of the reciprocative abutment is synchronized with the rotation of the rotor 38 in the previously described rotary device. Thus in-the course of a half of a revolution of the rotor blank 160 in FIGURE 14, the end mill 1.76 advances along an arcuate path in one direction generally longitudinally of the axis of rotation of the blank and in the next half revolution returns in the opposite direction in 'the same synchronized manner along the same path.

By virtue of the Scotch-yoke arrangement, the movement of the end mill 176 along this arcuate path is ac celerated and decelerated in what may be termed a sinusoidal manner, the end mill pausing to change direction at each end of the range of reciprocation. The end mill accelerates to a maximum rate of movement as it approaches the midpoint of this range and then decelerates progressively in the described varying manner as it moves beyond the midpoint. While the end mill moves laterally in thearcuate path, the lower end of the end mill is be tangential at all times to the desired cylindrical curvature of the rotor hub 36 and thus shapes the hub as well as the rotor blade 40;

FIGURE 160 shows three positions of the end mill 176 along its path of movement when the apparatus is adjusted as indicated in FIGURES 14, 14a, and 15. The spindle housing .198 is at its right limit position with the housing neck 204 at the right position in the ring 205 for shaping the right face of the rotor blade 40, as the rotor blank 160 is viewed in FIGURE 14. It is the acceleration of the end mill to maximum speed of lateral movement at the midpoint of its range of lateral movement that causes corresponding maximum pitch of the rotor blade 40 at the point midway between the two end walls of the chamber. i

When the rightward face of the rotor blade and the rightward portion of the rotor hub have been shaped by the arcuate movement of the end mill 117 6 along the path shown in FIGURE 16a, the apparatus is adjusted to advance the end mill against the rotor blank from the opposite side of the blank in the manner indicated diagrammatically in FIGURE 16b. For this purpose, the set screw 2.12 is withdrawn from the position shown in FIGURE 15 and is threaded into the second threaded housing 198 against the opposite side of the ring 205. The end mill 176 is then advanced against the rotor blank in the same synchronized manner to form the second face of the rotor blade 40.

Since the hand crank 170 may be rotated to shift the position of the rotor blank 160 along its axis, it is apparent that the thickness to which the rotor blade 40 is cut may be adjusted. Such adjustment may be made, for example, to oversize the thickness of the rotor blade to compensate for shrinkage when the rotor shaped by the apparatus is to be used as a pattern for casting a rotor. It is further apparent that the thickness of the rotor blade shaped by the apparatus may be undersized to form the previously described steel core 138 or a pattern for the steel core. Thus in preparing for the fabrication of a rotor having a steel core and a plastic sheath, the described apparatus is used to make a pattern for the steel core of the rotor and is used again to make a second pattern for the investment casting.

While employment of an arcuate reciprocative abutment moving in an arcuate path, as heretofore described, is highly advantageous for a number of reasons, nevertheless, a rotary device may be made in accord with the invention to incorporate a fiat abutment reciprocating along a straight path. FIGURES 17 and 18, for example, show how the previously described rotary device spindle housing for sliding engagement 14 may be modified'for substitution of a straight flat abutment for arcuate abutment.

The construction shown in FIGURES l7 and 18 is similar to the first described construction as indicated by the use of corresponding numerals to indicate corresponding parts. The reciprocative abutment 44a is simply a fiat plate-like member having the usual slot to receive the undulating blade 40a of a rotor 3811.. Rotary cylindrical sealing elements 5811 are arranged at both edges of the abutment slot for sealing cooperation with the rotor blade 40a in the manner heretofore described. Here again the way 1040 in which the abutment 44a reciprocates and the fluid passage 10511 that interconnects the two ends of the way are formed in part by the end section 684: of the casing, and the end section is formed with a partition 108a for this purpose. 1

The shape of the rotor blade 40a in this second embodiment of the invention is less complicated than heretofore described inasmuch as the reciprocative abutment 44a moves entirely in the plane of the rotor axis: so that no allowance need be made for departure of the abutment movement from that plane. The manner in which the rotor 3 8w with its blade 4011 may be shaped by an apparatus of the character heretofore described may be understood by reference to the FIGURE 19. The 198a in FIGURE 19 is mounted for lateral reciprocation along a straight tpath and carries the usual upright shaft 200a for rotating the usual end mill. To allow for the thickness of the rotor blade the neck 204a of the spindle housing is slidingly engaged by a longitudinal slot 215a in one end of a Scotch-yoke member 214a and may be held at either end of the slot by a set screw 235 which may be placed interchangeably in two threaded bores 236 and 238. The Scotch-yoke member is slidingly mounted in a fixed guide sleeve 216a and has the usual transverse slot 218a in its other end with a crank pin 22011. The crank pin 220a is mounted on a disc 222a that is actuated in a synchronized manner as heretofore described.

It is apparent that the spindle housing 198a will shift in the required harmonic or sinusoidal manner to give the undulating blade 40a the desired shape. In this instance the undulating blade 4011 will be curved in a simple sinusoidal manner to vary in pitch around its circumference and to vary in thickness for maintaining sealing contact with the cylindrical sealing elements 58a, all as heretofore described.

The rotor of either of the two embodiments of the invention described to this point may be termed a singleundulation rotor since the axially extending rotor blade reciprocates once between the two end walls of the annular chamber in the course of one rotation of the rotor. Thus with the rotor blade in contact with one of the end walls of the chamber in the region of the reciprocative abutment, of rotation of the rotor causes the rotor blade to shift across the chamber into wiping contact with the opposite wall of the chamber at the reciprocative abutment and during the next 180 of rotation the rotor blade shifts back into wiping contact with the first wall. The number of undulations may be increased as desired and the number of reciprocative abutments correspondingly increased to make a rotary device of this type which may serve either as a multiple pump or as a multiple fluid motor. By way of example, FIGURES 20 to 26 show how this first type of the invention may be embodied in a dual pump.

The dual pump has best shown in FIGURE 26. The configuration of the outer circumference or periphery of the two-undulation rotor blade is shown in FIGURE 27a and the configuration of the inner circumference or root portion of the rotor blade is shown in FIGURE 27b. It will be noted that one undulation of the rotor blade starts at 0 and 'ends at 180, each end of the undulation touching one of the chamber end walls and the mid-portion of the a two-undulation rotor 239 as undulation touching the other end wall. Thus 180 instead of 360 of rotation of the rotor will cause the rotor blade to shift back and forth across the chamber wall at a reciprocative abutment. The two reciprocative abutments are positioned 180 apart around the circumference of the annular chamber. In effect, the rotor blade reciprocates across the annular chamber twice as many times for one rotation of the rotor and therefore produces substantially twice as much volumetric displacement for each rotation. FIGURE 27b indicates clearly the manner of which the thickness of the rotor blade varies with the pitch angle for maintaining sealing efliciency at the intersection of the rotor blade with the reciprocative abutment.

As shown in FIGURE 22 the third embodiment of the invention as a dual pump has a casing comprising a main casing section 240, an end casing section 242 and two cover members 244 and 245. The main casing section 240 has the usual bosses 246 (FIGURE 21) to receive screws 248 for holding the two cover members in place, each cover member being provided with an O-ring 250 to prevent leakage. The previously mentioned rotor 239 has a hub 254 and an undulating blade 255. This rotor cooperates with the casing to form an annular chamber 256 having a cylindrical wall 258 and two opposite end walls 260 and 262. This chamber has two diametrically opposite oval openings 263, instead of one, and the pump has two reciprocative abutments 264, instead of one, each reciprocative abutment dividing the corresponding oval opening into two half portions. The main casing section 240 provides the cylindrical chamber wall 258 as well as the chamber end wall 260 and the end casing section 242 provides the second end wall 262 of the chamber. The end casing section 242 telescopes into the cylindrical wall 258 and is held in place by a split retaining ring 265 (FIGURE 22) which removably seats into an inner circumferential groove 266 in the cylindrical wall. A set screw 267 in the cylindrical wall 258 engages a recess 268 in the end casing section 242 for correct relative positioning of the parts and a suitable O-ring 270 surrounding the end casing section 242 prevents leakage.

In the construction shown, the end casing section 242 forms a port 272 which may be either an input port or an output port depending on the direction of rotation of the rotor and this port provides communication with two fluid passages, each of which is generally designated 274. These two fluid passages 274 which communicate with diametrically opposite points of the annular chamber 256 are formed in part by the end casing section, in part by the main casing section 240, and in part by the two cover members 244 and 245. Thus each of the two passages 274 has a portion 275 formed by the end casing section 242, a portion 276 formed by the main casing section 240 and a portion 278 formed by the corresponding cover member. Thus the two fluid passages 274 communicate respectively with half portions of the two oval chamber openings 263 on one side of each of the two reciprocative abutments 264.

Each of the two cover members 244 and 245 forms a port 282 and here again these two ports may be either input ports or output ports depending on the direction of rotation of the rotor. Each of the two ports 282 communicates with the other half portion of the corresponding oval chamber opening 263. Each of the two cover members has a dividing wall 284- in which a sealing element 285 is positioned for sealing contact with the corresponding reciprocative abutment 264.

Each of the reciprocative abutments 264 is of the configuration described in the first embodiment of the invention. Thus each reciprocative abutment 264 comprises an abutment wall 286 and a pair of radial arms 288 which are integral therewith and are also integral with a cylindrical pivot portion 290'. As shown in FIGURE 21, the arcuate abutment wall 286 reciprocates in an arcuate way 291, the opposite ends of which are interconnected by the usual fluid passage 292. The pivot portion 290 of each reciprocative abutment 264 rotatably seats in a corresponding bore 293 in the main casing section 242. As best shown in FIGURE 22, each of the reciprocative abutments 264 is formed with the usual slot to receive the undulating rotor blade 255 and this slot is provided with a row of cylindrical sealing elements 294 of nylon or the like. The cylindrical sealing elements 29.4 are mounted loosely on pins 295 and are positioned in cylindrical curved recesses 296 in the reciprocative abutment (FIGURE 21) in the manner heretofore described. The usual pair of semi-cylindrical sealing elements 298 of nylon (FIGURE 21) or the like are mounted in corresponding recesses 300 for sealing contact with the outer arcuate face of the abutment wall 286.

As may be seen in FIGURE 22 the rotor 239 may be of the previously described construction having a metal core covered with a sheath of nylon or the like. The rotor 239 is keyed to an enlargement 302 of a shaft 304, the shaft being journalled in two bearing bushings 305.

It is apparent that the two reciprocative abutments 264 cooperate with the rotor 239 to divide the annular chamber of the device intotwo sets of expanding compartments and two sets of contracting compartments. If the rotor 239 rotates in the direction to make the port 272 an intake port, the two passages 274 leading therefrom in opposite radial directions will communicate respectively with the two sets of expanding intake compartments and each of the two ports 282 functioning as an output port will be in communication with a corresponding set of the contracting output compartments. Thus two fluid cycles will occur simultaneously with the fluid taken in at the input port 272 divided between the two fluid cycles and with each cycle discharging to one of the two discharge ports 282. Since both of these fluid cycles are equally effective, it is apparent that this embodiment of the invention may function as a proportioning device to draw fluid from a single source and to divide the fluid equally between two separate distribution points. On the other hand, the direction of rotation of the rotor may be reversed to make the single port 272 function as an output port and to make the two ports 282 function as two separate input ports. With this reversal the device may function to draw fluids from two separate sources at equal rates and to deliver the fluid to a single destination.

The dual form of the pump is especially useful on an aircraft to withdraw fuel from tanks in the two wings of the aircraft simultaneously since it may be depended upon to draw the fuel at equal rates from both sources to keep the fuel load balanced with respect to the longitudinal axis of the aircraft.

The dual pump may also have two separate input ports and two separate output ports as indicated in FIGURE 28, there being an input port and an output port on each side of each of the two reciprocative abutments 264, just as the first described embodiment of the invention has an input port and an output port on opposite sides of its reciprocative abutment. With such an arrangement of two separate input ports and two separate output ports, the dual pump functions, in effect, as two interconnected pumps.

In FIGURE 28, a dual type rotary device 310 of this character has two separate input ports 312 and 314 and two separate output ports 315 and 316. A fuel tank 318 in one wing of the aircraft is maintained under substantial fluid pressure to cause fuel flow therefrom and is connected by a pipe 320 with the input port 312. In like manner a second fuel tank 322 in the otherwing of the aircraft, which is likewise maintained under substantial fluid pressure, is connected by a pipe 324 with the input port 314. The pressure of the liquid fuel in the two pipes 324 and 320 causes the rotary proportioning device 310 to withdraw the fuel from the two tanks 318

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