US2487685A - Rotary oscillating vane pump - Google Patents

Description

Nov. 8, 1949 R. W.YOUNG ROTARY OSCILLATING VANE PUMP s Shee ts-Sheet 1 TQai Filed March 20, 1945 INVENTOR. RAYMOND W. YOUNG.

ATTORNEY Nov. 8, 1949 R. w. YOUNG ROTARY OSCILL A'I'ING VANE PUMP 3 Sheets-Sheet 2 Filed March 20 1945 INVENTOR. RAYMOND W- YDLINE ATTORNEY Nov. 8, 1949 R. w. YOUNG 2,487,685

ROTARY OSCILLATING VANE PUMP Filed March 20, 1945 3 Sheets-Sheet 3 INVENTOR. RAY-MONO W- YDLINE.

A'T'TDRNEY Patented Nov. 8, 1949 ROTARY OSCILLATING VANE PUMP Raymond W. Young, Hohokua, N. J., assignmto Wright Aeronautical Corporation, a corporation of New York Application March 20, 1945, Serial No. 588,673

Claims. 1

This invention relates to pumps and is pardisplacement rotarypump.

In the operation of conventional positive-displacement rotary pumps, lubricating oil for the operating parts of the pump becomes intermingled with the fluid being pumped. This mixture of lubricating oil with the fluid being pumped frequently is quite objectionable in which case it is necessary to provide some means to separate the lubricating oil from the pumped fluid.

It is an object of this invention to provide a positive-displacement pump, primarily for pumplng gases and vapors, and having a minimum amount of friction and in which it is not necessary to use lubricating oil within the pump chamber. To this end, and in one form of the invention, adequate lubrication of the pump-operating parts is obtained by impregnating one of the rubbing surfaces of said parts with graphite. In a second form of the invention, said pump-operating parts are provided with oil-lubricated guide portions disposed outside the pump chamber and against which the pump-reaction forces are exerted.

Specifically, the invention comprises a pump having a rotor eccentrically-mounted within the pump chamber and having a plurality of vanes pivotally mounted at their inner edges about axes disposed around the outer surface of said rotor. Said vanes extends outwardly from said rotor and suitable spring means are provided which, together with the centrifugal force acting on the vanes, urges the outer edges of said vanes about their pivot axes toward contact with the inner wall of said pump chamber. With this construction, during pump operation each vane only oscillates relative to the pump rotor so that the friction therebetween is quite small. In addition, said vanes not only act as the fluid-displacing means of the pump but also provide for pump pressure relief at a pressure determined by the spring forces acting on the vanes.

Other objects of this invention will become apparent upon reading the annexed detailed description in connection with the drawing in which:

Figure l is an axial section through a pump embodying the invention, said section being taken along line |--i of Figure 2;

Figure 2 is a sectional view taken along line 2--2 of Figure 1;

Figure 2A is an enlarged sectional view of a modified portion of Figure 2;

Figures 3 and 4 are enlarged side and end views of one of the vane-operating springs illustrated in Figure 1;

Figure 5 is a view taken along line 5-5 of Figure 1;

Figure 6 is a view taken along line 6-6 of Figure 2;

Figure 7 is an enlarged perspective view of one of the pump vanes;

Figure 8 is an axial section through a modified pump and taken along line 8-8 of Figure 9;

Figure 9 is a broken sectional view taken along line 9-9 of Figure 8; and

Figure 10 is a fragmentary view of a modified pump rotor construction.

Referring first to Figures 1 to 7, particularly to Figures 1 and 2, a pump I0 is provided with a pump housing having a body portion [2 and end members l4 and I6 secured thereto. A cylindrical sleeve 18, fitted within said body portion, defines a chamber 20 therewithin having an axis indicated at 22 in Figure 2. The pump body portion I2 is provided with inlet and outlet ports 24 and 26 and conduits 28 and 30 are adapted to be connected to said body portion in alinement with said inlet and outlet ports respectively. The sleeve I8 is provided with a plurality of slots 32 and 34 at the inlet and outlet ports respectively, thereby establishing communication between said inlet and outlet ports and the pump chamber 20. Obviously, the sleeve I8 could be dispensed with in which case the slots 32 and 34 would be formed directly in the pump body portion.

The pump end members [4 and I6 provide opposed alined bearings 36 and 38 having an axis, indicated at 40 on Figure 2, offset from the axis 22 of the pump chamber 20. A pump rotor member 42 is disposed within the pump chamber 20 and said rotor member is piloted on radiallyextending flanges 44 and 46 on shaft members 48 and 50 journaled within bearings 36 and 38 respectively. The shaft member 48 extends beyond the pump housing and is provided with splines 52 to which suitable means (not shown) for driving the pump is adapted to be connected. Annular plate members 54 and 56 are suitably secured to the shaft flanges 44 and 46 respectively, for example by rivets 58, and the rotor member 42 is secured between said plate members by screws 60. Each annular plate member is provided with an equal plurality of bearings 62 within which the pump vanes 64 are journaled, as hereinafter described.

The construction of each pump vane 64 is vanes 64 and these vane parts are secured together b welding or brazing.

A hollow longitudinally-slotted tube 10 is fitted over the elongated cylindrical rib 68 at the outer edge of each vane. Each tube 10 has a longitudinal slot 12 and an internal bore 14 such that it may be securely fitted over the outer rib edges 68 of the vane elements by sliding this tube lengthwise over said rib edges. Preferably, each tube 10 comprises a suitable graphite-impregnated plastic. Such plastics are commercially available, e. g. under trade names Textolite or Synthane. In this way, each vane element is provided with a graphite-impregnated plastic tip which is readily replaceable. The use of plastic material for the pump vane tips is particularly suitable in that if any foreign matter should become trapped between a pump vane 64 and the adjacent cylindrical wall of the chamber 20, this foreign matter will tend to imbed itself within the plastic material instead of scratching this wall of the pump chamber. The addition of the graphite helps lubricate the engaging surfaces of the vanes 64 and the cylindrical wall of the pump chamber .to reduce the friction therebetween.

Each vane shaft portion 66 projects beyond each end of the body portion of its associated vane and these projecting portions are journaled within opposed bearings 62 carried by the annular plate members 54 and 56 and the body portion of the vanes extends between the end walls of the cylindrical pump chamber 20. The pump rotor member 42 is provided with a number of equally-spaced radially-extending flanges 16 equal to the number of pump vanes 64. One corner 18, defined by each of said flanges l6 and the adjacent surface of the rotor member 42, is machined to a cylindrical curvature similar to the curvature of the vane shaft portions 66 to provide a close fit with said portions. Thus, the bearings 62 carried by the annular plate members 54 and 56 have a spacing similar to the spacing of the radial flanges 76 such that, when the projecting ends ,of the vane shaft portions 66 are journaled within the bearings 62, the vane shaft portions are received with a minimum of clearance within said cylindrical corners l8. Actually, annular plate 54 and/or 56 with their bearings 62 may be used as a fixture for accurately locating and machining the corners 78.

The outer edges 10 of the vanes 64 are adapted to engage the interior surface of the pump chamber 20 such that, relative to the direction of rotation of the rotor member 42, the outer edges 10 of the vanes trail their inner edges 66. A suitable helical spring 80 is provided between the projecting ends of each vane shaft portion 66 and the adjacent annular plates 54 and 56 which springs, together with the centrifugal force acting on each vane, rotatively urge the outer vane edges 10 into engagement with the interior surface of the pump chamber 20.

With this construction, when a drive is applied to the shaft 48, in a direction indicated by the arrow in Figure 2, the vanes are caused to rotate with said rotor and the springs 80, together with the centrifugal force acting on the vanes 64, maintain the outer edges of the vanes in contact with the interior cylindrical surface of the pump chamber 20. Because of the eccentricity between the axes of the rotor member 42 and pump chamber 20, the vanes 64 oscillate relative to the rotor during pump operation as indicated in Figure 2. In this way, as the pump rotor and vanes rotate, fluid is trapped between the vanes and, because of the pivotal movement of the vanes about the bearings 62, the space between adjacent vanes becomes smaller as they approach the pump outlet port 26 thereby increasing the fluid pressure P to this outlet port. The graphite-impregnated tubes I0, at the outer edges of the vanes, provide adequate lubrication between the vanes and the interior of the pump chamber 20. Also, since the vanes 64 only oscillate relative to the rotor member 42, there is relatively-little friction therebetween.

One end of each of the springs is anchored to a vane shaft portion 66 in a bore 61 extending therethrough while the other end of each spring is adapted to be anchored in any one of a plural ity of recesses 82 in the associated annular plate 54 or 56, as seen in Figures 3 and 4. In this way, the spring force on each vane may be adjusted. This spring force, together with the centrifugal force acting on each vane, determines the maximum pump discharge pressure since, if the pump pressure against the vanes exceeds a certain value, it will rotate the vanes against their springs 80 and the centrifugal force acting on the vanes, thereby providing clearance between the outer vane edges 10 and adjacent wall of the pump chamber 26 to relieve pump pressure. Thus, for a given pump speed, the maximum pump discharge pressure can be varied by adjustment of the springs 80. A suitable removable plug 84 is provided at each end of the pump housing to provide easy access to the springs 80. Only one such plug is necessary at each end of the pump housing since the pump rotor 42 can be rotated to successively aline the vane springs 80 therewith.

With the aforedescribed construction, no lubricating oil is necessary within the pump chamber 26. The graphite-impregnated plastic tip along the outer edge of each vane provides suflicient lubrication to take care of the contact between the outer edge of each vane and the adjacent surface of the pump chamber 20. If the pump is operated at the maximum discharge pressure permitted by the spring and centrifugal forces on the vanes 64, then there will be substantially no contact pressure between the outer edge of each vane and the adjacent cylindrical wall of the pump chamber 20 for a portion of each revolution 01 each vane in the vicinity of the pump outlet port 26 thereby further reducing the amount of friction between the outer edge of each vane and the adjacent cylindrical wall of the pump chamber 20.

A suitable lubricant is provided for the pump bearings 48 and 50. In order to prevent this lubricant from finding its way into the pump chamber 20, each end member I4 and I6 is provided with an annular groove 66 within which a seal ring 88 is disposed. Each seal ring 88 is urged into engagement with the pump rotor by suitable spring means 90. The rings 88 may be of any suitable material such as carbon or other suitable seal ring material. Obviously, if desired or necessary, suitable seal means may also be provided between the outer surface of the pump rotor annular plates 54 and 56 and the adjacent end members I4 and I6 respectively.

The vanes 64 preferably have a curvature such that they are inwardly concave in. order to reduce the clearance volume of the pump. Thus, as illustrated in Figure 2, because of this vane curvature, the clearance volume between the adjacent wall of the pump chamber and a vane 64 is quite small as the vane rotates beyond the pump outlet port 26. Obviously, this clearance volume may be further reduced by providing an abrupt and inwardly-concave curvature for each vane 64 at its junction with its inner edge or shaft portion 66.

Referring now to Figure 8 and 9, which illustrate a modified form of the invention, a pump H0 is provided with a body portion H2 and an end member H4 at one end thereof. The pump body portion IIZ provides a cylindrical pump chamber I I6 as in Figures 1 to '7 but in the modification of Figures 8 and 9, the end member H4 is separated from the body portion II2 by an annular partition IIB thereby defining an end chamber I20. Preferably, the end chamber I20 is co-axial with and has a diameter equal to the diameter of the pump chamber HE. A pump rotor member I22 is suitably secured to a shaft portion I24 which, in turn, is journaled within the bearing I26 carried by the end member H4. The axis of the rotor member I22 is eccentric relative to the axis of the pump chamber IIB as best seen in Figure 9. Suitable seal rings I20 are provided between an annular radial flange I29 on the pump shaft I24 and the partition II8 thereby providing a seal between the pump chamber H6 and the end chamber I20. The opposite end of the pump from the end member II4 has not been illustrated but preferably is substantially the same as the construction of Figures 1 to '7.

Pump vanes I30 are journaled about the pump rotor i22 as in Figures 1 to '7 except inFigures 8 and 9, one end of the shaft portion I32 at the inner edge of each pump vane is extended into the end chamber I20 and a guide vane I34 is keyed or otherwise secured thereto. Adjustable helical spring means I30 are provided as in Figures 1 to 7 for urging each vane I30 toward engagement with theadjacent wall of the pump chamber II6. In addition, each spring means I36 also urges each guide vane I34 into engagement with the adjacent surface of the end chamber I20.

The arrangement is such that each guide vane contacts the cylindrical surface or track of its end chamber I20 to relieve its associated pump vane I30 of actual contact pressure with the surface of the pump chamber H6. With this construction, there is little or no friction between the pump vanes I30 and the interior of the pump chamber II6. In the end chamber I20, the friction and wear between the guide vanes I34 and the end chamber I20 may be reduced by the introduction of lubricating oil therein-for example, from the pump bearing I26. The presence of lubricating oil in the end chamber I20 is not objectionable since the chamber I20 is sealed from the pump chamber IIB by rings I28. In addition, the guide vanes I34 and pump vanes I30 may be provided with graphite-impregnated plastic tubes I38 and I over their outer edges as in Figures 1 to 7 thereby further reducing the pump friction. The vanes I30 and I34 preferably have the same shape, but the plastic tubes I40 have a slightly larger outer diameter than the tubes I38 whereby the vanes I30 are relieved of actual contact pressure with the cylindrical surface of the pump chamber I I6. However, the clearance between the outer edges of vanes I30 and the cylindrical surface of the pump chamber I I6 is quite small.

The provision of the graphite-impregnated plastic tubes I38 at the outer edges of vanes I30 is in the nature of a safety feature to prevent undue friction between the vanes I30 and the pump chamber H6 in case there is appreciable wear of the tubes I40 at the outer edges of guide vanes I34. The guide vanes I34 are also provided with stiffening webs I42. The construction of Figures 8 and 9 is otherwise similar to the structure of Figures 1 to '7. At this point it should be noted that it is not necessary that chambers I I0 and I20 be of the same diameter.

In both of the aforedescribed modifications there is only a small amount of relative motion between the inner edge of each vane and the adjacent pump rotor. However, if desired, the pump friction may be further reduced by providing a graphite-impregnated slotted plastic tube over the inner shaft portion 66 or I32 of each vane similar to the tubes 10 or I38 provided at their outer edges. Such a construction is illustrated in Figure 2A in which a graphite-impregnated longitudinally-slotted plastic tube I40 is fitted over the inner shaft portion 08 of a vane 64. Figure 10 illustrates a slight modification of this construction in which a graphite-impregnated plastic tube I50 is fitted within slotted cylindrical bores within the pump rotor I52 in alinement with vane bearings at the ends of the pump rotor. Each tube I50 is longitudinallyslotted as indicated at I54, whereby the inner edge or shaft portion 66 or I32 of each vane 64 or I30 may be assembled therewith by sliding lengthwise therein. Also, the width of each slot I54 is sufficient to accommodate the angular movement of the associated vane relative to the pump rotor.

The aforedescribed modifications provide a positive-displacement rotary pump especially suitable for pumping gases or vapors and in which no lubricating oil is required in the pump chamber and in which the pump operates with a minimum of friction. ,In addition, in each modification the fluid-displacing means or vanes of the pump also act as a pressure relief valve.

While I have described my invention in detail I in its present preferred embodiment, it will be obvious to those skilled in the art, after understanding my invention, that various changes and modifications may be made therein without departing from the spirit or scope thereof. I aim in the appended claims to cover all such modifications.

I claim as my invention:

l. A pump vane having a cylindrical rib along one edge thereof, and a longitudinally-slotted graphite-impregnated plastic tube fitted over said rib, the slot in said tube being arranged to permit said tube to be slid longitudinally over said rib.

2. A pump comprising a housing having a cylindrical chamber therewithin and having fluid inlet and outlet parts communicating with said chamber, a pump rotor member eccentrically mounted within said chamber, a plurality of vane members pivotally mounted about the outer periphery of said rotor member and extending outwardly therefrom toward the cylindrical surface of said chamber for pumping fluid from said inlet port to said outlet port upon rotation of said rotor member, each or said vane members having a substantially-cylindrical rib along its inner and outer edges and a longitudinally-slotted graphite-impregnated tube disposed about said cylindrical ribs along the inner and outer edges of said vane members.

3. A pump vane having a longitudinal rib along one edge thereof, and a longitudinally-slotted tube fitted over said rib, the slot in said tube being arranged to permit said tube to .ie slid longitudinally over said rib.

4. A pump comprising a housing having a first chamber therein with fluid inlet and outlet ports communicating with said chamber, and a second chamber within said housing co-axial with but out of communication with said first chamber; a pump rotor eccentrically mounted within said first chamber; a. piurality of vanes pivotally carried by and extending outwardly from said rotor for pumping fluid. from said inlet port to said outlet port upon rotation of said rotor; a plurality of guide members in said second chamber each secured to' one of said vanes for joint pivotal movement of each vane and its guide member about the pivot axis of said vane; said guide members extending into engagement with the outer wall of said second chamber for enforcing pivotal movement of said guide members and their vanes in response to rotation of said rotor such that in each position of a guide member the outer end of its associated vane is disposed in close proximity to the outer wall of said first chamber,

5. A pump comprising a, housing having a first chamber therein with fluid inlet and outlet ports communicating with said chamber, and a second chamber within said housing co-axial with and axially spaced from said first chamber but out of communication with said first chamber; a pump rotor eccentrically mounted within said first chamber; a plurality of vanes pivotally carried by and extending outwardly from said rotor for pumping fluid from said inlet port to said outlet port upon rotation of said rotor; at pluraiity of guide members in said second chamber each secured to one of said vanes for Joint pivotal movement of each vane and its guide member about the pivot axis of said vane; said guide members extending into engagement with the outer wall of said second chamber for enforcing pivotal movement of said guide members and their vanes in response to rotation of said rotor such that in each position of a guide member the outer end of its associated vane is disposed in close proximity-to the outer wall of said first chamber.

RAYMOND W. YOUNG.

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

UNITED STATES PATENTS Number Name Date 1,010,388 Kirby Nov. 28, 1911 1,515,961 Meyer Nov. 18, 1924 1,601,397 Kachendarfer Sept. 2a, 1926 1,657,096 Sprague Jan. 24, 1928 1,669,779 Reavell May 15, 1928 1,743,539 Gasal Jan. 14, 1930 1,818,430 Ricardo Aug. 11, 1931 1,877,250 Meyer Sept. 13, 1932 2,004,563 Bogaslowsky June 11, 1935 2,033,719 Lamb Mar. 10, 1936 2,137,708 Wilson et a1. Nov. 22, 1938 2,247,429 Aikman July 1, 1941 2,323,926 McGill 1 July 13, 1943 2,338,112 Hell Jan. 4, 1944 FOREIGN PATENTS Number Country Date 6,122 Germany 1879 17,613 Germany Apr, 3, 1882 106,521 Great Britain May 22, 1917 294,653 Great Britain June 6, 1929 5 564,411 France Oct. 18, 1923 606,765 France Mar. 13, 1926

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