US2630963A - Rotary aspirator pump - Google Patents

Description

March 10, 1953 R. c. scHLlcHTlG 530,963

ROTARY ASPIRATOR PUMP' Filed sept. 27, 1945 2 SHEETS-SHEET 2 rwentor Patented Mar. 10, 1953 UNITED STATES PATENT OFFICE 4 Claims.

My invention is in the nature of a rotary aspirator pump. The principal object of my invention is to provide a pump of this character which is capable of developing much greater pressure than the theoretical pressure of a centrifugal pump of like diameter and speed of rotation, and which is also capable of operating in reverse as a uid turbine of high efciency.

A device embodying my invention may be utilized for many purposes. For example one objective application is to accomplish approximate adiabatic compression of the gaseous working medium of a heat transfer mechanism. In reverse it may be utilized to effect approximate adiabatic expansion of the gaseous medium of a heat transfer mechanism. It is also useful in the compression of air or fuel mixtures to supercharge internal combustion engines, in transforming energy of fluids under pressure into mechanical energy, compressing air or vapors for use in various low pressure mechanisms and such other elds as the removal of vapor from one vessel to another in distillation processes.

My invention is embodied in an aspirator construction wherein an aspirator throat leading from a low pressure chamber or area to be evacuated has an injector duct leading centrally into the throat and providing therewith a restricted cross section Where fluid of relatively high velocity from the injector picks up iiuid in the throat. The fluid flow is directed against a torodial conoid forming the central portion of a rotor so as to change the direction of the fluid from axially of the rotor to radially of the rotor. The rotor is provided with blades that take the uid from the central portion initially in substantially a radial direction and then curve in the direction of rotation of the rotor to the periphery of the rotor so as to eiect a restriction of the cross section of the fluid passages at the periphery and to utilize the centrifugal force of the fluid outwardly against the advancing blades to increase the velocity of the fluid in the direction of rotation of the rotor. The construction is also such as to eiect constriction of depth of the passages between blades as these passages approach the periphery of the rotor. Thus the pressure energy of the iluid in the rotor is further converted into velocity energy by reason of the constriction of the passages. The velocity of the fluid is therefore at its maximum at the periphery of the rotor. This also` is the point of lowest pressure in the system. The discharge from the rotor is in a direction nearly tangential to the rotor into outwardly expanding passages for converting the velocity energy of the fluid into pressure energy in a toroidal chamber around the outer ends of the passages.

The novel features of my invention are set forth with particularity in the appended claims. This invention itself, however, both as to its embodiment in a practical device and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment when read in connection with the accompanying drawings in which: v

Figure 1 is a face view of an aspirator pump constructed in accordance with the invention, certain parts being broken away to illustrate the interior construction;

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

Figure 3 is a fragmentary sectional view taken on the line 3 3 of Figure 1; and

Figure 4 is a fragmentary sectional view taken on the line 4 4 of Figure 1, but showing a modication of fluid feed to the rotor.

Referring now to the drawings, the pump comprises a back casing section '5 which may be mounted upon a support 6 by screw-bolts 1. The support E mounts a bearing 8 for a rotor shaft 9. A rotor In is carried by the shaft which extends through a seal plate II which is backed up by a spring I2 that in turn bears against a Washer I3 that is mounted on the shaft 9 against the rotor II). The housing of the rotor is completed by a front casing section I li which is bolted to the section 5 at the periphery. A suitable gasket is used to seal the two casing sections together.

The two casing sections 5 and I4 have outer semicircular portions 5a and Ida which form a toroidal chamber I5 at the periphery of the casing. Inside this chamber there is an annular restricted passage I6 that extends in to the periphery of the rotor. This passage is sometimes referred to hereinafter as the diffuser chamber of the pump. The section 5 has ribs I1 thereon which are tapered in thickness and which are approximately tangential to the rotor periphery on the rotor facing surface thereof. The section Illrests on the ribs I 1.

The section It has an inwardly extending rotor cover portion I8 that terminates in a rounded inner lip I9. Over the portion If8 the section I4 is formed with a wall 20 that extends to a restricted injection nozzle .2I, the inner edge 22 of which extends into the space within the lip I9. A pressure duid manifold 23 leads from the toroidal chamber f5 inwardly to the nozzle 2'I.

A low pressure inlet 24 is provided to the space around the nozzle 2i. A high pressure fluid connection to the chamber I5 is provided at 25. The chamber l5 has a partition 23 arranged with offset portions 29 and 39 directing fluid from the diffuser passages le to either the conduit .23 or the conduit L25.

In Figure 4 of the drawings, the low pressure inlet is provided by several openings 24a that enter the rotor chamber just outwardly of the rotor periphery. This space is the space of lowest pressure in the system due to the high velocity discharge of fluid across it from the constricted passages between the rotor blades.

The rotor I0 has a center 26 that extends out through the injection nozzle 2i. ri`he outer portion of the member 25 is a true cone Ybutv the inner portion is of toroidal shape. The rotor also has blades 21 extending outwardly from the base of the .center 25. These-blades as shown are highest at their inner ends and' cover itis shaped to fit closely over them. The blades at their inner ends extend in substantially a radial direction with respect to the rotor axis. Toward their outer ends the blades curve forwardly in the direction of rotation of the rotor to approach alignment-at their outer ends, with the ribs li. As shown in the drawings each 'rotor blade at its outer ends has its inner 'surface directed forwardly and outwardly at'anangle of about sixty degrees to a radial linefromthe Vcenter of the rotor through the outer Vend of the blade. The blades of `the rotor must 'not be pitched so steeplyforward that the fluid' moved radially outward by centrifugalforce would be deflected inwardly aga-in by the blades. Such acondition would decrease the velocity of the fluid toward the diffuser, and, defeat thepurposes of the present invention. rIhe blades 2'! causean outward flow of fluid through .the spaces between the diiuser blades l1 without the help of high` pressure at the inlet 23. This curvature and the reduction in blade depth. greatly reduces the cross section of uid passage' at the periphery of the rotor. It is evident from aninspection of Figure 1 that as the blades approach the outer periphery of the rotor they are curved more nearly to the curvature of the rotor periphery. The distance directly across the space between adjacent blades from one blade to the other thus decreases when they approach the rotor periphery. Each blade 21 is somewhat thickened toward its outer end whichfurther reduces the cross section of the space between the blades.

The operation in principle is as follows: Let

P1 be the pressure energy of a given volume (say l cc.) of fluid in the pressure manifold 23 and Pc be the added pressure energy that is impressed on the fluid by centrifugal force due to rotation of the rotor and the blades 2l; with d as the density' of the fluid and Vc as the velocity of travel at the circumference of the rotor. The pressure energy Piel-Pc is converted into kinetic energy of velocity as the stream of fluid is forced through the narrow aspirator channels between the blades 21.

The relative velocity of the fluid stream at the periphery of the rotor with respect to the rotor velocity is given by the formula V:\/2(P1}Pc /d where theY pressure energy is substantially all converted to kinetic energy of velocity. Since the velocity of the rotor iii at the periphery is Vc the total uid velocity V is Vc+\/2(P11Po) /d. As thefenergy is proportional to the square of the total velocity and since this energy is converted (except for friction losses) into pressure by the diverging ribs H in the diiuser I6 this pressure Pz will equal l/zlZV2 0r As P14-Pc would be the pressure at the diffuser l if only centrifugal force (such as is found in the regular centrifugal pump) were called into playit apparent that the pressure developed in this pump is much greater than in' a plain centrifugal pump of like size and speed. In practice I have developed a pressure more than iive times that of a centrifugal pump of the same size and speed. The necessary energy to obtain this high pressure is supplied to the shaft 9 by a suiiiciently powerful motor. I nd also that the pump has a `large volume-capacity. Furthermore due to the high velocity imparted to the fluid in the rotor it I get a very low intake pressure in the intake manifold 24. Thus the big pressure diiierence is between 2li and i6.

In operating the device as a turbine, flow takes place in the reverseorder and the extreme high pressure in iB drives the rotor il) to deliver power to the shaft 9. The spent iiuid discharge may be through both the manifold M and the nozzle 22, but of course the conduit 23 is not connected to the chamber I5.

The center Zeef the rotor is adapted to serve two purposes. The outer or tip'p'ortion'is Va true cone and serves as a means of vforming the restriction at Vthe nozzle 2i of the aspirator. The inner toroidal conoid surface changesthe direction of the iiuid from predominantly axial with respect to the rotor to a radial direction on'the rotor. The radial position ofthe aspirator inlet nozzle 2i with respect to the rotor is not critical. In other words, the cone center 2S may be larger or smaller and the injector nozzle 2i may be a narrower slot on a larger circle or may be much smaller in diameter and be less restricted by the cone center.

Havingthus described my invention, I claim:

l. An aspirator pump comprising a rotor having tapered blades extending outwardly and curving forwardly in the direction of rotation, the blades approaching each other and decreasing in width toward the rotor periphery to provide fluid passages which are constricted toward the outer edge of the rotor, and which extend forwardly in the direction of rotation of the rotor from their inner ends to their outer ends, an enclosing housing having a diffuser chamber projecting outwardly from the outer edge of the rotor, said housing also having concentric fluid inlets to the rotor, and means to conduct part of the uid from said diffuser to the inner of said inlets, said means comprising a toroidal chamber about the diffuser, a return conduit having its inlet end connected to the toroidal chamber and having its outlet end directed toward the rotor on the axis of the rotor and an injector nozzle on said conduit forming the inner inlet.

2. An aspirator pump comprising a rotor having tapered blades extending outwardly and curving forwardly in the direction of rotation, the blades approaching each other and decreasing in width toward the rotor periphery to provide iiuid passages which are constricted toward the outer edge of the rotor, and which extend forwardly in the direction of rotation of the rotor from their inner ends to their outer ends, an enclosing hous ing having a diffuser chamber projecting outwardly from the outer edge of the rotor, said housing also having concentric fluid inlets to the rotor, and means to conductl part of the fluid from said diffuser to the inner of said inlets, said means comprising a toroidal chamber about the diluser, a return conduit having its inlet end connected to the toroidal chamber and having its outlet end directed toward the rotor on the axis of the rotor and an injector nozzle on said conduit forming the inner inlet, and means to separate the rest of the fluid discharged from the diiuser from the part returned to the inner inlet, comprising an annular radial partition in said toroidal chamber.

3. An aspirator pump comprising a rotor having curved uid passages extending in a radial direction on the rotor and inclined forwardly in the direction of rotation of the rotor, the maximum forward inclination being at the rotor periphery and being insuiiicient to overcome the outward ow of the fluid in said passages due to centrifugal force, said passages being gradually restricted in cross sectional area from their inner ends to their outer ends, an enclosing housing having a diffusing chamber at the periphery of the rotor into which said passages discharge, said housing having concentric annular high pressure and low pressure inlets opening to the rotor, and the rotor center having a pointed tip projecting into the high pressure inlet and curving outwardly at its base toward the inner ends of said passages.

4. An aspirator pump comprising a rotor having a raised center curving outwardly toward its base and having blades on the base extending outwardly from said center and, the inner ends of said blades being directed substantially radially to the rotor and the blades curving forwardly in the direction of rotation of the rotor to the periphery thereof, the blades being decreased in height and their adjacent faces being brought closer together toward the outer ends thereof to provide passages between the blades that de- 6 crease in cross section from the inner ends to the outer ends of said blades, an enclosing housing having diffuser channels leading outwardly and forwardly from the periphery of said rotor, which channels increase in cross section as they recede from the rotor, said housing having concentric iiuid inlets opening to the center of said rotor, partition means in said housing at the outer ends of said diffuser channels separating the outlet ends of part of said diiuser channels from the outlet ends of the other diffuser channels and a conduit leading from one side of said partition means to the inner inlet.

RALPH C. SCHLICHTIG.

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

UNITED STATES PATENTS Number Name Date 900,814 Wilson Oct. 13, 1908 1,063,294 Seaver June 3, 1913 1,075,300 Moss Oct. 7, 1913 1,267,897 Pagel May 28, 1918 1,946,524 Crosthwait Feb. 13, 1934 1,985,705 Whiton, J1 Dec. 25, 1934 2,083,996 Jonn June 15, 1937 2,096,883 Clason Oct. 26, 1937 2,335,109 Conery Nov. 23, 1943 2,343,486 Stepanoi Mar. 7, 1944 2,352,094 Griswold June 20, 1944 FOREIGN PATENTS Number Country Date 7,783 Great Britain 1913 13,161 Great Britain June 6, 1913 404,632 France Oct. 25, 1909 475,781 France 1915 695,713 Germany Aug. 1, 1940

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