|Publication number||US1345639 A|
|Publication date||Jul 6, 1920|
|Filing date||Sep 14, 1914|
|Priority date||Sep 14, 1914|
|Publication number||US 1345639 A, US 1345639A, US-A-1345639, US1345639 A, US1345639A|
|Inventors||Henry F Schmidt|
|Original Assignee||Westinghouse Electric & Mfg Co|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (3), Classifications (4)|
|External Links: USPTO, USPTO Assignment, Espacenet|
H. F. SCHIVIIDT.
FLUID TRANSLATIIIG DEVICE.
APPLICATION FILED SEPT. 14, 19M.
Patented July H I2 0 IN VEN TOR.
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Specification. of Letters Patent.
Application filed September 14 191%. Serial Ito. serene.
To all whom it may concern:
Be it known that I, HENRY F. SCHMIDT, a
citizen of the United States, and a resident,
of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have made a new and. useful Invention in Fluid-Translating Devices, of which the following is a specification; l
This invention relates to fluid translating devices, such, for example, as ejectors, in which the kinetic or velocity energy of the motive fluid is employed in exhausting fluid from a receptacle to be evacuated, or in compressiiig a fluid from a region of lower to a region of lngher pressure.
In e ectors employing dlffusers for bu1ldin u) oressure b7 convertin lrinetic into potential or pressure energy, pulsations in the medium. traversing the diffuser occur to r various reasons. If these pulsations are of sufficient magnitude thatthe loss occasioned by shock results in a sufficient diminution of the velocity of the medium, and consequently of the available kinetic energy, so that the energy is reduced below that necessary to overcome the external or discharge pressure, the velocity in the diffuser will instantly fall to zero. This willreduce the expelling force to zero and consequently occasion a flow in the reverse dircctioiti or from the outlet of the diffuser back into the reg-ion of lower pressure.
AnWobject of this invention is, therefore, to produce an ejectorin which means are employed for preventing pressure oscillations inthe diffuser-from becoming large enough to detrimentally affect the operation ottheejector. i 1 a t A further object of the invention is to produce a fluid translating device,of the lnnetlc type, inwhich means are employed for maintalnmg the OPBTZLlJlOIlOf the device substantially constant for practically all varying conditions. j
A still further object is to produce a fluid translating device employing the kinetic or velocity energy, of the motive fluid delivered to it, in transferring fluid from a region of lower to a region of higher pressure, which automatically adjusts itself to variationsin the quantity of fluid conveyed, thus prevent-- ing fluctuations of pressure in; eitherrthe region of higher or lower pressure.
These, and other objects, which will be madeapparentsto those skilled in the art more or less dia rammatically, a sectional view of an ejector embodying my invention. The ejector illustrated comprises a suction and combining chamber 3, which is provided with an inlet port a, a nozzle 5 for discharging fluid from a source of fluid pressure through the combining and suction chamber, and a diffuser 6, which communirates with the chamber 3 and through which the combined media, issuing from the nozzle 5 and the chamber 3 are discharged to the atmosphere or to a region of higher pressure with relation to the pressure maintained in the chamber 3. 'llhe port l is adapted to communicate with the region of lower pressure or with a receptacle to be evacuated.
its illustrated, the diffuser tube terminates in a chamber 7, which, in the illustrated embodiment, communicates with the atmosphere through a port 8, and incloses a disk 9 capable of closing communication between the outlet of the diffuser and the chamber 7, but which is normally held in such a po sition, with relation to the outlet of the diffuser, as to occasion a slight increase in pressure of the media traversing the diffuser at a point immediately adjacent to the diffuser outlet. its illustrated, the chamber 7 is provided with a wall 10, which forms an annular flange around the outlet of the diffuser 6 and with which the disk 9 is adapted to cooperate in providing an annular dis charge nozzle, of variable area between the difluser and the chamber 7. In order that the disk may move to automatically adjust its position with relation to the wall 10 to accommodate varying rates of discharge through the diffuser 6, l have shown it mounted on a spindle 11, which is slidably mounted within a bearing l2,mou nted within the chamber 7, and extends axially with relation. to the diffuser. With this arrangement the disk is not only capable of moving axially with relation to the diffuser, but is prevented from moving laterally. l have also shown a coil spring 15, surrounding the spindle l'land operating between the hear ing supporting brackets 18 and the dish, for holding the disk in an operative position retested duly e, men,
with relation to the wall 10. The disk is also provided with a conical deflector 14, which extends into the outlet end of the diffuser and operates to direct the steam from the diffuser into the annular nozzle formed by the cooperation of the disk and the wall 10. This deflector is provided merely for the purpose of reducing the tendency toward the formation of eddy currents which might result from the sudden change in the direction of the fluid.
The operation of the apparatus is as follows: The motive fluid traversing the nozzle 5 is expanded and discharged at a high velocity into the combining and suction chamber 3, through which it flows in entering the diffuser 6. In traversing the chamber 3, the fluid discharged from the nozzle 5 entrains the fluid or medium to be ejected or compressed, and conveys it through the diffuser. As the combined media traverse the diffuser 6, their velocity is decreased, occasioning a conversion from kinetic to potential energy, which appears as an increase in pressure of the media at the dischargeend of the diffuser, or immediately adjacent to the inlet of the annular nozzle formed by the cooperation of the disk 9 and the wall 10. The combined media in traversing the annular nozzle are locallyv over expanded, between the inlet and outlet of the nozzle,
. thereby occasioning a partial conversion of the potential into kinetic energy. The ratio of the diameter of the mouth of the diffuser 6 to the diameter of the disk 9 is such that an over expansion occurs in the annular nozzle, at some point intermediate the center and the outer edge of the disk 9, thereby causing the pressure of the media traversing the nozzle to fall below that existing in the chamber 7. By over expansion .is meant an expansion of fluid traversing a nozzle, so that its pressure at some point within confines of the nozzle is below the pressure existing at the outlet of the nozzle, or in the present example, below the pressure existing within the chamber 7. It will be noted that the nozzle formed between the disk 9, and the wall 10, may be termed a divergent nozzle, since the fluid passage between the disk and the plate increases in area from the inlet, near the center of the disk, toward the outlet at the periphery of the disk. As a matter of fact, the nozzle disclosed is a convergent divergent nozzle; the rounded edge of the wall 10, at the juncture of that wall with the diffuser 6, forms, with the conical deflector 14, a convergent nozzle, whereas the flat portion of the wall 10 and the disk 9,, form a divergent nozzle. Inasmuch as the pressure difference between the outlet of the diffuser 6 and the chamber 7, is less than the reduction in pressure capable of being obtained by employing a converging nozzle, the converging portion of the nozzle illustrated, will first expand the fluid issuing from the diffuser (3. and there-- by cause its pressure to drop. The expansion, due to the velocity thus engendered, will continue in the initial portion of the divergent nozzle, i. 0., the initial portion of the nozzle located between the disk 9 and the wall 10, to such a point, that over ex iiansion is accomplished. The remaining portion of the divergent nozzle will, acting as a diffuser, re ,*onvert the velocity energy of the fluid, re sulting from the expansion, into pressure energy and consequently build up the pres-are of the fluid as its velocity slows down. The disk is further so proportioned with relation to the diameter of'the mouth of the diffuser that the pressure in the chamber T acting on the disk is suflicient to balance the force exerted on the disk by the combinial media at the mouth of the diffuser. With such an arrangement a desired pressure can be maintained in the chamber 3 and a cow dition of equilibrium established in the diffuser G which cannot be upset by variations or fluctuations which may tend to be set up within the media traversing the diffuser. This is due to the fact that the media discharged from the diffuser has a relatively free flow outwardly through the annular nozzle, whereas a flow in the reverse direc tion, or from the chamber 7 into the diffuser is restricted, since to obtain such a flow it would be necessary for the pressure on the diffuser side of the disk 9 to fall below that in the chamber 7. This would cause the disk 5) to approach the wall 10 and to restrict the flow from the chamber 7, thereby preventing the formation of harmonic \lln'ations in the diffuser, since such variations can only exist when the resistance to their propagation is the same in each direction longitudinally of the vibrations.
The disk 9, therefore, moves to different positions in response to the variations in flow through the diffuser 6, and, operating as a check to a reverse flow through the diffuser, overcomes the tendency toward upsetting when a minimum amount of. fluid is being ejected from the chamber It will be apparent, to those skilled in the art, that the apparatus shown is merely illustrative, that the nozzle 5 may be replaced by a series of nozzles, or by a series of nozzles including accelerating nozzles operating either in parallel with or in series with the main expelling nozzles, and that various changes, substitutions. additions or omissions may be made in the apparatus illustrated without departing from the spirit and scope of the invention as set forth by the appended claims.
What I claim is.
1. In an apparatus of the character described, a diffuser, a chamber communicating therewith, means for delivering a jet of Lea-aces flu id thrbugh the diffuser for entraining medrum in the chamber, and means cooperating with the outlet of the diffuser for oc- Ill casioning a partial expansion of the fluid issuing therefrom, and movable in response to variations in the partial expansion for varying the outlet of the diffuser.
2. In combination with a compressible fluid. ejector, means cooperating with the outlet of the ejector for occasioning a partial expansion of the fluid issuing from the outlet end of the ejector and movable in response to variations in the pressure resulting from said expansion, for controlling the delivery of fluid through the outlet of the ejector.
3. In "combination with a fluid ejector, means cooperating with the outlet of the ejector for occasioning a local expansion of thefluid issuing from the outlet of the ejector, and movable toward and away from the outlet, in response to variations in the local expansion of the fluid.
4t. In combination with an ejector, a disk movably mounted at the outlet of the ejector diffuser, and cooperating therewith to form an expansion nozzle for the fluid issuing from the ejector.
5. In combination with an ejector, means cooperating with walls of the ejector diffuser outlet for over expanding the fluid issuing from the outlet, and movable toward and away from the outlet in response to variations in the expansion occasioned thereby.
6. In combination with an ejector, means for causing a local over expansion of the fluid issuing from the outlet of the ejector said means being arranged to prevent a reverse flow of fluids so as to dampen the harmonic vibrations tenchng to arise 1n the ejector diffuser due to variations in the flow of the e ecting and e ected fluids.
7. I11 combination wlth an e ector, a disk I mounted at the outlet of the ejector diffuser nozzle for expanding motive fluid and for delivering it at a high velocity into and through a mixing chamber, a mixing chamher, a d ifluser communicating therewith and receiving fluid therefrom, and an annular nozzle for receiving the combined media issuing from the diffuser and located at right angles to the axis of the diffuser.
9. In combination in an ejecting apparatus, a receiving chamber communicating with'a source of fluid to be ejected, a diffuser communicating therewith and a nozzle for expanding fluid to the pressure normally existing in the receiving chamber and for discharging the fluid so expanded into and through said chamber and said diffuser, and an annular passage extending at right angles to the axis of the diffuser and through which. fluid issuing from the diffuser is discharged.
In testimony whereof I have hereunto subscribed my name this 21st day of Am gust, 191 f.
IIENlt-Y I. SCHMIDT.
U. I/V. ltfofinnn, IE. W. ltIcCALLIs'ren.
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