US3242867A

US3242867A - Fluid pumping and separating apparatus

Info

Publication number: US3242867A
Application number: US351053A
Authority: US
Inventors: Bruce H Mosbacher
Original assignee: Roper Industries Inc
Current assignee: Roper Technologies Inc
Priority date: 1964-03-11
Filing date: 1964-03-11
Publication date: 1966-03-29
Anticipated expiration: 1983-03-29

Description

March 29, 1966 B. H. MOSBACHER 3,242,867

FLUID PUMPING AND SEPARATING APPARATUS Filed March 11} 1964 United States Patent 3,242,867 FLUID PUMPING AND SEPARATING APPARATUS Bruce H. Mosbaclier, Rockford, Ill., assignor to Roper Industries, Inc., Rockford, 11]., a corporation of Illinois Filed Mar. 11, 1964, Ser. No. 351,053 12 Claims. (Cl. 103-6) This invention relates to improvements in fluid pumping and separating apparatus.

An important object of this invention is to provide a positive displacement type pumping apparatus having expansible and contrac-tible pumping compartments arranged in an annular bank for centrifugally separating and discharging the separated fluid-s in separate streams, and which apparatus is arranged to provide improved radial separation of the fluid in the pumping compartments.

A more particular object of this invention is to provide a positive displacement type pumping apparatus having a casing and expansible and contractible pumping compartments arranged in an annular bank for rotation relative to the casing to centrifugally separate the fluids, and which apparatus is arranged to reduce the frictional drag between the fluid in the pumping compartments and the walls of the casing to thereby minimize turbulence and enhance centrifugal separation of the fluids.

An important feature of the present invention resides in the provision of a pumping apparatus including a rotor defining segregated expansible and contractible pumping compartments disposed in an annular bank around the rotor, and in which the rotor has plates attached to opposite sides and overlying the sides of the pumping compartments to enclose the pumping compartments, and wherein the outlet openings are formed in at least one of the plates adjacent one peripheral wall of the compartments and spaced radially from the other peripheral wall of the compartments to effect selective discharge of the centrifugally separated materials from the compartments.

These, together with other objects and advantages of this invention, will become apparent as the following detailed description proceeds when taken in connection with the accompanying drawings wherein:

FIG. 1 is 'a sectional view through the pump and separating apparatus taken on the plane 11 of FIG. 2 and illustrating the-apparatus connected in a pumping system;

FIG. 2 is a sectional view taken of the plane 2-2 of FIG. 1; and

FIG. 3 is a sectional view through a modified form ofpumping apparatus.

In many applications, such as in lubrication systems, hydraulic control systems and fuel delivery systems, it is desirable to deliver the fluid substantially free of air and gas. The fluid pumping and separating apparatus of the present invention not only operates as a positive dis placement pump to positively draw the fluid into the pump from a supply reservoir or the like, but to also provide positive discharge of the fluid under pressure. The ap paratus in general includes a casing, herein shown as a multiple section casing having a body 10, a port plate 11, an annular ring 12 defining a pump chamber, and an end plate 13, the several parts being held together in assembled relation as by bolts 14. In the embodiments illustrated herein, the pumping apparatus is of the in ternal gear type and includes an annular internally toothed outer rotor 16 which is rotatably supported in the pump chamber for rotation about the axis of the outer rotor. The rotor 16 is conveniently supported at its outer periphery on the ring member 12. An externally toothed inner rotor 17 is disposed within the outer rotor and is 3,242,867 Patented Mar. 29, I966 'ice drivingly connected to a shaft 18 for rotation about an axis eccentric to the outer rotor. The shaft 18 is conveniently rotatably supported in the body 10 and end plate 13 and is connected to the inner rotor 17 as by a key 19. The inner rotor has at least one less number of teeth than the outer rotor and the teeth -17' on the inner rotor are shaped to form a running seal with the teeth 16' on the outer rotor, as the inner and outer rotors rotate about their relatively eccentric axes designated A and B in FIG. 1.

The shaft 18 is driven by any suitable means, such as is diagrammatically indicated at 21 in FIG. 2, to rotate the inner and outer rotors about their respective axes and to centrifugally separate the fluid in the compartments into radially inner and outer layers according to the relative densities of the materials. In the internal gear pump of the type described, the inner and outer peripheral walls of the compartments rotate together so that there is little frictional drag at the inner or outer periphery of the compartments. However, the ends of the pumping compartments in an internal gear pump are generally closed by the stationary walls of the pump casing. It has been found that the resistance or drag imposed on the fluid adjacent the ends of the pumping compartments produces turbulence and inhibits complete separation of the fluid in the compartments into inner and outer layers, particularly when the rotors have a relatively small axial dimension. In accordance with the present invention, plates designated 25 and 26 are provided at opposite ends of one of the rotors. The plates are connected to one of the rotors for rotation therewith and extend outwardly to enclose the sides of the pumping compartments so that the side walls of the pumping compartments rotate therewith and thereby minimize drag and frictional resistance to rotation of the fluid with the pumping compartments. The

plates

25 and 26 are preferably secured to the inner rotor and, as shown, are attached thereto by rivets 27. The plates extend outwardly into overlapping relation with the outer rotor 16, as best shown in FIG. 2, to enclose and seal the ends of the pump compartments. At least one of the plates such as 26 is disposed in close running fit with the port plate 11 and the other plate 25 on the rotors is preferably disposed in close running fit with the other end member 13 on the pump casing.

At least one of the plates 26 is formed with a plurality of openings therein and which openings cooperate with ports in the port plate 11 to supply and exhaust fluid from the pumping compartments. The openings, designated 31, are arranged adjacent one of the peripheral walls of the compartments to provide selective discharge of the centrifugally separated fluids from the compartments. It has been found. preferable to discharge the gaseous fluid first and, accordingly, the openings 31 are located closely adjacent the inner periphery of the compartments and are spaced radially inwardly from the outer periphery of the compartments. In the embodiment of FIGS. 1 and 2, the openings 31 are in the form of holes located at the roots of the .teeth on the inner rotor.

As previously described, the

teeth

17 and 16 on the inner and outer rotors form segregated pumping compartments therebetween, which pumping compartments progressively expand in one sector of the chamber, that is at the right side of a plane, hereinafter sometimes referred to as the plane of eccentricity, through the axes A and B of the inner and outer rotors, and the compartments progressively contract on the other side of that plane. One or more inlet ports are formed in the port plate 11 to communicate with the openings 31 as they move past the inlet Zone, and to supply fluid to the compartments during expansion of the compartments. With fluid to the separating apparatus.

this arrangement, the expanding compartments, positively draw fluid thereinto so that it is unnecessary in many applications to provide a separate boost pump to supply In the embodiment shown, two inlet ports designated 33 and 34 are provide in the port plate 11, it being understood that a single inlet port or a greater number of inlet ports may be provided, if desired. The inlet ports are located at one side of the plane of eccentricity and are angularly spaced apart a distance at least equal to, and preferably slightly greater than, the circumferential width of the openings 31 and the plate 26. The

inlet ports

33 and 34 are radially positioned so as to register with the opening 31 as the latter rotate thereby, and the

separate ports

33 and 34 are conveniently arranged to communicate with different rservoirs, sumps, receptacles or the like designated 38 and 39 in FIG. 1. For this purpose, port 33 in the plate 11 is connected through a passageway 41 in the casing body and through a supply line 42 to the reservoir 38. The other port 34 is connected through a passageway 43 in the pump body and supply line 44 with the reservoir or receptacle 39.

The fluid from the reservoirs or sumps frequently contain some occluded air and gas, particularly in systems wherein one or the other of the sumps may have some time or other run dry. For example, the

reservoirs

38 and 39 could correspond to so-called climb and dive sumps in an aircraft engine, which climb and dive sumps receive fluid at relatively different times, depending upon the attitude of the airplane. The pump and separating apparatus will centrifugally separate the liquid and gaseous fluids, supplied to the apparatus through

inlet ports

33 and 34, and discharge the same in separate streams. An air and gas discharge port designated 46 is provided in the port plate and has one end 46a angularly spaced in the direction of rotation of the pumping compartments (indicated by the arrow in FIG. 1) from the end of the inlet port 34. The port 46 is arranged to communicate with the openings 31 in the plate 26 during the initial contraction of the compartments. Since the openings 31 are located adjacent the radially inner edge of the compartments, that is, adjacent the roots of the teeth on the inner gear, the relatively lighter centrifugally separated air and gas is forced outwardly through the openings 31 and through the first outlet port 46. The latter is connected through a passage 48 in the pump casing to a conduit 49. This air and gas outlet conduit is conveniently connected to one of the reservoirs such as 38, to return the air and gaseous fluid along with any liquid fluid that is separated with the air and gas. An air vent 51 is conveniently provided on the reservoir 38 to vent off the excess gas and air and maintain the reservoir under substantially atmospheric pressure.

One or more liquid outlet ports are provided for discharging the relatively heavier liquid from the compartments, during the subsequent contraction of the same. In the embodiments shown, a single liquid outlet port designated 53 is provided, it being understood that additional liquid outlet ports could be provided and circumferentially spaced from each other. The liquid outlet port 53 also has its ends designated 53a and 53b angularly spaced from the adjacent outlet port 46 and inlet port 33 a distance approximately equal to, and preferably slightly greater than, the circumferential width of the openings 31 in the plate 26. The port 53 is radially positioned so as to communicate with the openings 31 as the compartments rotate past the port 53, to thereby discharge the liquid fluid under pressure through the port 53. The latter is connected through a passage designated 56 to a delivery line 57 leading to the point of use of the fluid.

A modified form of pumping apparatus is illustrated in FIG. 3, In this embodiment, the pump casing and the inner and outer rotors are constructed and formed in the same manner as that described in connection with FIGS. 1 and 2,' and like numerals are used to designate corresponding parts. In this embodiment, however, the port plate designated 26' is'formed with modified openings designated 31'. The openings 31 are advantageously made oblong to minimize the radial extent of the openings, While yet providing adequate flow area to prevent excessive restriction to the flow of fluid into and out of the pumping compartments. The oblong openings permit the radially outer edge of the openings to be located closely adjacent the roots of the teeth of the inner gear, to assure discharge of any air from the compartment during the initial contraction of the same. In addition, the openings 31' are preferably located so as to be relatively closer to the side of the compartment that leads during rotation. In stroboscopic examination of positive displacement centrifugal separating apparatus, it was found that there was some tendency for the liquid fluid to lag or build up toward the trailing side of the compartments and force the gaseous fluid toward the lead side. Olfsetting of the openings 31' in the manner set forth above toward the lead side of the compartments accommodates the above-described tendency of the fluid to lag in rotation of the compartments. With the oblong openings, it is, of course, necessary to increase the spacing between adjacent ports and the port plates so that they are spaced apart, a distance approxiamtely equal to, and preferably slightly greater than, the circumferential width of the opening 31.

In order to minimize the volume of fluid that remains in the pumping apparatus between the port plate 46 and the pumping compartments, the plate 26 is preferably made relatively thin and, as shown, is very thin as compared to the axial length of the rotors. While openings 31 are herein shown formed in one of the plates 26, it is apparent that corresponding openings could be provided in the other plate 25 and a pump casing provided with suitable ports and passages to communicate with the additional openings, to thereby introduce and withdraw fluid from both ends of the compartments instead of from a single end as in the disclosed apparatus.

From the foregoing it is thought that the construction and operation of the pump and separating apparatus will be readily understood. The

plates

25 and 26 rotate with the rotors and enclose the ends of the pumping compartment so as to minimize frictional drag and resistance to the rotation of the fluid with the. pumping compartments. Since the openings 31 and 31' in the rotor plates are located closely adjacent one with the peripheral walls of the pumping compartments, one with the centrifugally separated fluids in the compartments will be preferentially discharged through the first port such as 46 while the remaining fluid will be discharged through the other outlet port 53. In the preferred embodiment, the openings 31 are located adjacent the air periphery of the compartments to provide initial discharge of the air and gaseous fluid from the compartments. Since the radial positioning of the openings 31 in the plate 26' determines which of the fluids will be discharged first, it will be seen that it is unnecessary to accurately control the radial positioning of the ports in the port plate 11, so long as these ports communicate with the openings 31 in the plate 26' at the proper time.

Although the invention has been described in connection with certain specific embodiments, the principles herein are susceptible to numerous other applications that will readily occur to persons skilled in the art. The invention is, therefore, to be limited only as indicated by the scope of the appended claims.

I claim:

1. A positive displacement pump and separating apparatus for separating fluids of different densities comprising, a pump casing having spaced walls defining a pump chamher, inner and outer eccentrically related rotors in said chamber having means extending therebetween defining a plurality of segregated pumping compartments having inner and outer walls, plates attached to opposite sides of,

3 one of said rotors for rotation therewith and extending into overlapping relation with the other of said rotors to enclose the sides of the pumping compartments and reduce frictional drag between the fluid in the compartments and the walls of the chamber, one of said plates having a plurality of openings therein located closely adjacent one of the walls of the compartments and spaced radially from the other walls of the compartments, means for rotating said rotors to centrifugally separate fluid in the compartments into inner and outer layers according to the relative densities of the fluids, said rotors being supported for rotation about relatively eccentric axes whereby the compartments progressively expand during one portion of each revolution as they move past an inlet zone and progressively contract during a different portion of each revolution as they move past a discharge zone, said casing having inlet port means communicating with said openings as they move past said inlet zone whereby expansion of the compartments draws fluid in through the inlet port means, said casing having a first outlet port communicating with said openings as they move past a first sector of said discharge zone and a second outlet port communicating with said openings as they move past a second sector of said discharge zone.

2. The combination of claim 1 wherein said openings are elongated in a direction circumferentially of the pumping compartments.

3. The combination of claim 1 wherein said openings are located relatively closer to the lead side than to the trailing side of the compartments.

4. A positive displacement pump and separating apparatus for separating fluids of different densities comprising, a pump casing having spaced walls defining a pump chamber, inner and outer eccentrically related rotors in said chamber having means extendingtherebetween defining a plurality of segregated pumping compartments having inner and outer walls, said rotors being supported for rotation about relatively eccentric axes whereby the compartments progressively expand during one portion of each revolution as they move past an inlet compartment and progressively contract during a different portion of each revolution as they move past a discharge zone, plates attached to opposite sides of one of said rotors for rotation therewith and extending into overlapping relation with the other rotor to enclose the sides of the pumping compartments and reduce frictional drag between the fluid in the compartments and the walls of the chamber, one of said plates having a plurality of openings therein located closely adjacent the inner walls of the compartments and spaced inwardly from the outer walls of the compartments, means for rotating said rotors to centrifugally separate fluid in the compartments into inner and outer layers according to the relative densities of the fluids, said casing having inlet port means communicating with said openings as they move past said inlet zone whereby expansion of the compartments draws fluid to be separated into the compartments, said casing having a first outlet port communicating with said openings as they move past a first sector of said discharge zone whereby the initial contraction of the compartments forces fluid containing the lighter centrifugally separated components from the compartments, and a second outlet port communicating with said openings as they move past a second sector of said discharge zone whereby subsequent contraction of the compartments forces fluid containing the heavier components from the compartments.

5. A positive displacement pump and separating apparatus for separating fluids of different densities comprising, a pump casing having spaced walls defining a pump chamber, inner and outer eccentrically related rotors in said chamber having means extending therebetween defining a plurality of segregated pumping comone portion of each revolution as they move past an inlet compartment and progressively contract during a different portion of each revolution as they move past a discharge zone, plates attached to opposite sides of said inner rotor for rotation therewith and extending into overlapping relation with said outer rotor to enclose the sides of the pumping compartments and reduce frictional drag be-! tween the fluid in the compartments and the walls of the chamber, one of said plates having a plurality of openings therein located closely adjacent the inner walls of the compartments and spaced inwardly from the outer walls of the compartments, means for rotating said rotors to centrifugally separate fluid in the compartments into inner and outer layers according to the relative densities of the fluids, said casing having inlet port means communicating with said openings as they move past said inlet zone whereby expansion of the compartments draws fluid to be separated into the compartments, said casing having a first outlet port communicting with said openings as they move past a first sector of said discharge zone whereby the initial contraction of the compartments forces fluid containing the lighter centrifugally separated components from the compartments, and a second outlet port communicating with said openings as they move past a second sector of said discharge zone whereby subsequent contraction of the compartments forces fluid containing the heavier components from the compartments.

6. The combination of claim 5 wherein said ports in said casing are angularly spaced apart a distance approximately corresponding to the angular width of said openings in the plates.

7. A positive displacement type pump and separating apparatus for separating fluids of different densities comprising, a pump casing having spaced walls defining a pump chamber, an internally toothed outer ro'tor rotatably mounted in the chamber and a cooperating externally toothed inner rotor having at least one less number of teeth than said outer rotor, said rotors being supported for rotation about relatively eccentric axes and the teeth on said rotors maintaining a close running seal therebetween to define a plurality of segregated compartments that progressively expand during one portion of each revolution as they move past an inlet zone and progressively contract during a different portion of each revolution as they move past a discharge zone, plates attached to opposite sides of one of the rotors for rotation therewith and extending into overlapping relation with the other rotor to enclose the sides of the compartments and reduce frictional drag between the fluid in the compartments and the walls of the casing, one of said plates having a plurality of openings therein located closely adjacent the roots of the teeth on one of the rotors and spaced radially from the roots of the teeth on the other of the rotors, means for rotating said rotors to centrifugally separate the fluid in the compartments into inner and outer layers according to the relative densities of the fluids, said casing having inlet port means communicating with said openings as they move past said inlet zone whereby expansion of the compartments draws fluid to be separated into the compartments, said casing having a first outlet port communicating with said openings as they move past a first sector of said discharge zone whereby initial contraction of the compartments forces a portion of the centrifugally separated fluid from the compartments through the first port, and a second outlet port communicating with said openings as they move past a second sector of said discharge zone whereby subsequent contraction of the compartments forces another of the centrifugally separated fluids from the compartments.

8. A positive displacement type pump and separating apparatus for separating fluids of different densities comprising, a pump casing having spaced wall defining a pump chamber, an internally toothed outer rotor rotatably mounted in the chamber and a cooperating externally toothed inner rotor having at least one less number of teeth than said outer rotor, said rotors being supported for rotation about relatively eccentric axes and the teeth on said rotors maintaining a close running seal therebetween to define a plurality of segregated compartments that progressively expand during one portion of each revolution as they move past an inlet zone and progressively contract during a different portion of each revolution as they move past a discharge Zone, plates attached to opposite sides of the inner rotor for rotation therewith and extending into overlapping relation with the outer rotor to enclose the sides of the compartments and reduce frictional drag between the fluid in the compartments and the walls of the casing, one of said plates having a plurality of openings therein located closely adjacent the roots of the teeth on the inner rotor and spaced radially from the roots of the teeth on the outer rotor, means for rotating said rotors to centrifugally separate the fluid in the compartments into inner and outer layers according to the relative densities of the fluids, said casing having inlet port means communicating with said openings as they move past said inlet zone whereby expansion of the compartments draws fluid to be separated into the compartments, said casing having a first outlet port communicating with said openings as they move past a first sector of said discharge zone whereby the initial contraction of the compartments forces fluid containing the lighter centrifugally separated components from the compartments, and a second outlet port communicating with said openings as they move past a second sector of said discharge zone whereby subsequent contraction of the compartments forces fluid containing the heavier components from the compartments.

9. The combination of claim 8 wherein said plates are thin as compared to the axial width of the rotors.

10. The combination of claim 8 wherein said openings are elongated in a direction circumferentially of the inner rotor.

11. The combination of claim 8 wherein said openings are located relatively closer to the lead side of the tooth spaces on the inner rotor than to the trailing side.

12. A- positive displacement rotary pump and separating apparatus comprising, means including a casing having a chamber therein and a rotor disposed in said chamher defining a plurality of expansible and contractible pumping compartments arranged in an annular bank around the rotor and having inner and outer walls, means for rotating said rotor about an axis paralleling said annular bank to centrifugally separate the fluids in the compartments, said rotor being located eccentrically in said chamber whereby the inner and outer walls of the compartments move away from each other during one portion of each revolution to progressively expand the compartments as they move past an inlet zone and the inner and outer walls move toward each other during a ditferent portion of each revolution to progressively contract the compartments as they move past a discharge zone, inlet means including at least one inlet passage com-i municating with said compartments as they move past said inlet zone for supplying fluid thereto containing liquid and gaseous fluids of relatively different densities whereby expansion of the compartments draws the fluids to be separated into the compartments, plates attached to opposite sides of said rotor for rotation therewith and extending outwardly to enclose the sides of the pumping compartments and reduce frictional drag between the fluid in the compartments and the walls of the chamber, one of said plates having a plurality of openings therein located closely adjacent the inner walls of the compartments and spaced radially inwardly from the outer walls of the compartments, said casing having inlet port means communication with said openings as they move past said inlet zone, said casing having a first outlet port communicating with said openings as they move past a first sector of said discharge zone and a second outlet port communicating with said compartments as they move past a second sector of said discharge zone.

References Cited by the Examiner UNITED STATES PATENTS 2,053,919 9/1936 Pigott 103-126 2,417,701 3/1947 Parsons 103-126 2,539,044 1/1951 Walsh 103126 2,732,802 1/1956 Eames 103-426 2,871,831 2/1959 Patin 103-126 SAMUEL LEVINE, Primary Examiner.

W. L. FREEH, Assistant Examiner.

Claims

1. A POSITIVE DISPLACEMENT PUMP AND SEPARATING APPARATUS FOR SEPARATING FLUIDS OF DIFFERENT DENSITIES COMPRISING, A PUMP CASING HAVING SPACED WALLS DEFINING A PUMP CHAMBER, INNER AND OUTER ECCENTRICALLY RELATED ROTORS IN SAID CHAMBER HAVING MEANS EXTENDING THEREBETWEEN DEFINING A PLURALITY OF SEGREGRATED PUMPING COMPARTMENTS HAVING INNER AND OUTER WALLS, PLATES ATTACHED TO OPPOSITE SIDES OF ONE OF SAID ROTORS FOR ROTATION THEREWITH AND EXTENDING INTO OVERLAPPING RELATION WITH THE OTHER OF SAID ROTORS TO ENCLOSE THE SIDES OF THE PUMPING COMPARTMENTS AND REDUCE FRICTIONAL DRAG BETWEEN THE FLUID IN THE COMPARTMENTS AND THE WALLS OF THE CHAMBER, ONE OF SAID PLATES HAVING A PLURALITY OF OPENINGS THEREIN LOCATED CLOSELY ADJACENT ONE OF THE WALLS OF THE COMPARTMENTS AND SPACED RADIALLY FROM THE OTHER WALLS OF THE COMPARTMENTS, MEANS FOR ROTATING SAID ROTORS TO CENTRIFUGALLY SEPARATE FLUID IN THE COMPARTMENTS INTO INNER AND OUTER LAYERS ACCORDING TO THE RELATIVE DENSITIES OF THE FLUIDS, SAID ROTORS BEING SUPPORTED FOR ROTATION ABOUT RELATIVELY ECCENTRIC AXES WHEREBY THE COMPARTMENTS PROGRESSIVELY EXPAND DURING ONE PORTION OF EACH REVOLUTION AS THEY MOVE PAST AN INLET ZONE AND PROGRESSIVELY CONTRACT DURING A DIFFERENT PORTOIN OF EACH REVOLUTION AS THEY MOVE PAST A DISCHARGE ZONE, SAID CASING HAVING INLET PORT MEANS COMMUNICATION WITH SAID OPENINGS AS THEY MOVE PAST SAID INLET ZONE WHEREBY EXPANSION OF THE COMPARTMENTS DRAWS FLUID IN THROUGH THE INLET PORT MEANS, SAID CASING HAVING A FIRST OUTLET PORT COMMUNICATING WITH SAID OPENINGS AS THEY MOVE PAST A FIRST SECTOR OF SAID DISCHARGE ZONE AND SECOND OUTLET PORT COMMUNICATING WITH SAID OPENINGS AS THEY MOVE PAST A SECOND SECTOR OF SAID DISCHARGE ZONE.