US1730748A - Pump - Google Patents

Description

H. F. SCHMIDT PUMP Filed Jan. 21. 1928 Oct. 8, 1929.

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Patented Oct. 8, 1-929 HENRY F. SCHIMIDT, OF 'LANSDOWNE, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA PUMP Application filed January 21, 1928; Serial .m. '24s,'44a.

My invention relates to fluid translating apparatus and more particularly to propeller type blowers or pumps, and it has for an object, to improve the efticiency of apparatus of this character.

Another object is to provide means for improving the efficiency of diffusers having relatively large angles of divergence,

my invention is shown drawings, wherein: I Fig. 1 is a section throu h vergent channel Fig. 2 is a diagrammatl Fig. 3 is a section through divergent channel; and? Fig. 4 is a section throng i f essecasing of a propeller type bloweijgand'showing the rotor elements in elevation:"'v y In the flowof fluid through a convergentdivergent channel it sometimes occurs, es-

- should, of course, be avoi passes directly through the diffuser: without 7 peciallv wherethe divergent portion has rela- ,-tively largeangles of divergence, that .-the ;ffi fluiddoesnot follow the walls of the diffuser but issuesifrom the throat in the form'flof' passes through the central portion 7 leaving dead spaces'andvor-" tices adjacent the walls thereof, as is clearly;

' 1, in which the direc'tion ot flow through the convergentwlivergentychannel 10 is indicatedby .the particles of fluid being indicated by the fine This condition Y of the diffuser,

shown in Fig.

lines within 'the channel.

' ded,-.,as= the fluid undergoing velocity-pressii'r e coiiversio 1 by conditions somewhat analogous'to those shown in Fig. 2, in which a ball 11, if it experiences no friction, would pass, from a state of rest at 12, down the inclined plane 13 to the base thereof, and up the inclined plane 14 to the position 15, which is at the same elevation as the position 12. However,

tormin g a part of this specification,

:reg1on, indicated 'fall of pressure onvergent-- iwhich is accumulative,

the diffusing cone.

tion, such as that indicated at 16, and then ,runs'back downthe plane 14.

Due to friction, Apparatus exemplifying the features'f'off inthe accompanying;

particles of fluid adjacent the walls of the difluser behave similarly to tliebalLll shown in'Fig. 2. Considering Fig. 3, each element of fluid flowing from the 1 by the reference character 17, to the throat of the convergent-divergent channel 10 would acquire velocityfrom the between these twopoints. The kinetic energy of a particle-of fluid at the throat would, therefore,-

the case of a perfect fluid, be sufiicient to-enable it to pass through the diffuser against the adverse pres sure head, but ,due to the friction between the walls of the diffuser and the particles of fluid, there is a retarded flow along these walls and'the more rapid ow of elements otfluid'nearer the center of f th e stream have-aw tendency to produce vorices -such as the vortices 19 and 21', indicated Fig; 1.- These,

in turn, may product aux? iilia ry eddies 22 and 23, which may have a whirlingmotion in the opposite direction to that of the vortices' 19 and 21. It will be understood, of course, that the vortices and arrows, the path of otlier eddy currents are unstable and some break away andiare carried down the stream leavingdead spaces on either 'side of the 1st.

the elements of fluid to follow the walls of In Fig. 3, I show a suitable number of passages 26 and 27 which afford communication between suitable openings such as holes, or slots 28 about the diffusing cone and similar openings 29 about the convergent portion of the convergent-divergentchannel. The relatively low pressure In order to'bvercome these objectionable I p features, I have provided means for causing The conditions shown in Fig. lar -caused? [in that portion of this channel which converges in the direction of fluid flow, causes fluid to be drawn from the vicinity of the walls of the diifuser through the passages 26 and 27 and into the convergent portion. In

this way, the fluid is assisted to' follow the i as described with reference to Fig. 3. In this case, however, each end of the tubular passages, 26, 2'1 is connected to a suitable box 32 which fits against the casing 10' and encloses one of the slotted holes 28 01229. A suitable prime mover, such as a turbine 33, is connected to operate the propeller 31, and disposed in the divergent portion of the channel are suitable guide vanes 34.

Any suitable number of passages, such as 26, 27 may be provided, and the holes 28 in the diffuser are, preferably, at different distances from the throat of the channel, as shown, in order to insure the particles of fluid following the walls for the entire length of the diffusing cone. The holes 28 servingeach set of passages 26, 27 maybe arranged in circumferential rows, and, if desired the holes in one row may be staggered with respect to those in the next, in order to further reduce any tendency for retarded flow.

While a plurality of the openings 28 in the diffuser may be connected by a common pasopenings about the divergent portion of the casing, and means for conducting fluid from said openings into the convergent portion 'of said casing.

5. The combination with the convergentdivergent casing of a-propeller type pump, of means providing a plurality of circumferentially and axially spaced openings about the divergent portion of the casing, and means for conducting fluid from said openings into the convergent portion of said casing.

In testimony whereof, I have hereunto subscribed my name this seventeenth day of 1 January, 1928.

sage to the convergentportion of the casing,"

I prefer to have independent passages for each opening in the difiusing cone in order to avoid the possibility of merely short circuit y ing fluid from one opening in the diffusing cone to another.

In this way it is possible to obt in th 1 sired velocity-pressure conversion with a relatively short diffusing cone. important in propeller type pumps,blowers, and the like, for the diffusing cone often encompasses a portion of the prime mover, such as the turbine 33, so that it is difficult to gain This becomes HENRY F.SGHMIDT.-

access to various parts of the prime mover, as I for example to the gland. By using a shorter dilfusing cone, this objection is overcome.

lVhile I have shown my invention in but one form, it will be obvious to those skilled" in the art that it is not solimited, but is sus-' ceptible of various changes and modifications,

' 'without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. The combination with a convergent-divergent channel, of means providing one or more exterior passages between the divergent and the convergent portions of the channel;

2. The combination With a convergent-di-

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