US1138125A - Fluid-ejector. - Google Patents

Description

M. LEBLANC.

FLUID HECTOR. APPLICATION FILED sEPLZI, 19m.

1, 1 38,125. Patented May 4, 1915.

IN VENTOR.

MW AW.

HIS ATTORNEY IN FACT.

onrrnn STATES PATENT OFFICE.

MAURILTEF'. LEELANC. OF AU'TEUIL. PARIS, FRANCE. ASSIGNOR. BY MESNE ASSIGNMENTS, TO SOCILTTE ANONYME POUR LEXPLOITATION PRCICEDES WESTINGHOUSE- LEBLANC. OF PARIS, FRANCE.

FLUlD EJECT' R.

Spool fication of Letters Patent.

Patented May 1, 1915.

Original application filed September 10. 1907. Serial P10392122. Elvicled and this application filed September [3e it. known that l. Mar'mru Immune, a citizen of the llepublic of France. residing at. Villa Montmorency. Autenil. .laris, France. have made a new and useful invention in l luid-lljcetors. of which the following is a specification, this application being a. division of an application filed by me on September 10. 1907, serially numbered .lillhlii.

This invention relates to ejector-s operated by steam or any other elastic fluid.

.\n object. of this invention is to produce a self starting ejector which is capable of maintaining a high vacuum. In accomplishing this. I provide an ejector in which means are employed for varying. in effect, the sectional area of the throat of the mixing cone in accordance with variations in the vacuum obtained.

In the drawings acconipanying this application and forming a. part thereof, Figures 1 and 3 are diagrannnatic views indicating in longitudinal section two different forms of ordinary ejectors. Fig. l is :1 diagrammatic longitudinal section of an ejector embodying my invention.

Fig. 1 discloses an ordinary ejector to which the motive fluid is supplied under pressure through a nozzle 4 which communicates with a. chamber 5. A passage (3 communicates with the. chamber 5 and is located opposite to the nozzle l. and is ordinarily termed a mixing cone. The motive fluid delivered by the nozzle -l traverses the chamber 5 at; a high velocity and this velocity of the fluid transformed into pressure energy as the fluid traverses the cone 6. The motive fluid in passing through the chamber 5 entrains by friction the fluids contained therein and also the fluid delivered thereto, through an inlet port 7 communicating with the chamber. These fluids before coming into contact with the stream of fluid delivered by the nozzle 4 must pass annular directing nozzles S. and 9. located in the chamber 5 and axially alined with the nozzle 4: and the cone 6. The cone 6 exhausts into a space 10 in which a. constant pressure, as for example the pressure P is maintained. If it is desired to maintain a working pres Serial No. 583.993.

\Vhen the ratio vary as the ratio air. is smaller than this number. the mixing cone should at first eon verge, and then diverge as shown in Fig. The conjunctit'in 11 of the convergent and divergent portions of the mixing cone (i of the apparatus of Fig. 2 is called the throat. This throat should be made smaller with respect to the inlet end of the convergent portion of the cone t) as the ratio diminishes.

Assuming that the ejector shown in Fig. :5 is constructed to maintain a high vacuum in the chamber 5, then, it will be apparent, that on starting the apparatus the pressure p in the chamber 5 will be equal to the pressure l at the exhaust end of the cone 6: and during the period preceding the establish- J ment of working cmnhtlons, the ratio will pass through all the values, included between unity and the value correspoinling to the desired working conditions. ln order to be self starting, the cone 6 of the ejector should be of such form that it would be incapable of performing the necessary functions after the working or normal conditions are established. Furthermore, the ejector would refuse to work and the pressure p in the chamber 5 would pile up, and become greater instead of less than the pressure I, if the nozzle (5 were of the form most suitable for normal working conditions. EX- perience shows that an ejector with a convergent mixing cone followed or not by a divergent mixing cone, cannot be started unless the convergence. isslight; that is to say. unless the ratio of the throat section to the inlet section of the mixing cone is apfi (I proximately equal to 1. It follows, that an ejector proportioned so as to be capable of maintaining a high vacuum, after working conditions have been established, cannot be started. Conversely, an ejector, in which all the parts are incapable of variation, but which is so constructed that it is self starting is unable to produce a high vacuum.

in order to produce an ejector which shall be capable of producing a high vacuum, I find it is necessary to produce means whereby the sectional area oi the throat may be comparatively large during the starting period, and may gradually diminish or de crease as the pressure p in the chamber 5 decreases. l find that it is necessary to auto matically control .the variation in the sectional area of the throat. in accordance with the variations in the pressure obtained in the mixing cone, in order that the eiiect of the apparatus may be constant and in order that the apparatus may be self starting after an accidental derangement. The cross sectional area of the throat of the convergent mixing cone may, for examplc, be varied. by varying the position of the walls of the throat, in accordance with my invention as disclosed in the application filed by me September 10, 1907, and heretofore referred to. The cross sectional area of the throat may also be varied by providing openings or apertures along the length ofthe convergent walls of the mixing cone o passage which are capable of being opened and closed to meet the varying conditions in the ejector. If these apertures are successively opened and closed, theithroat of the mixing cone will, in efi'ect, move along the length of the convergent portion of the cone and will always be located at the open aperture. The section of the throat will, there fore, gradually vary as one holeis opened and the preceding hole is closed.

In the apparatus illustrated in Fig. 3, as an embodiment of my invention, I provide an ejector equipped with a nozzle 4, for operating fluid, a chamber 5 provided with a port 7, entraining nozzles 8 and 9, and a mixing tube comprising a series of alined truncated cones 12, 13 and 14, and a divergent spout'or nozzle 23. The cones are con nected together by means of wings 15 and a determined amount of clearance is provided between the outlet of each cone and the inlet of the next adjacent cone. These clearance spaces consist of annular passages surrounding the cones and communicating by means of outlets 16, 17 and 18 with a receiving chamber 19, which is in free communication with the space maintained at the'constant pressure P into which the fluid discharged from the ejector is to be exhausted. The outlets 16, 17 and 18 'are respectively provided with clack valves 20, 21 and 22 which are adapted to automatically lift when the pressure at the outlet of each of the truncated cones 12, 13 and 11 can be less, by any amount, than the pressure 1, but can never.

rise an appreciable amount above the pressure P. The cones 1'2, 13 and 14- correspond to the convergent portion of the mixing cone 6 of Fig. 2 and the outlets 1U, 17 and 18 cor respond to the apertures or openings to which 1 have before referred as being provided along the length of the convergent portion of the mixing cone forthc purpose of varying, in effect, the area of the throat of the nozzle. It will be apparent that it the number of openings, located along the convergent portion of the cone, is sutiiciently large, the ejector will start automatically. If, for example, the truncated cone 12 were the only cone of the axia'lly alined system, the ejector would be self starting it the convergence of this truncated cone were sufliciently small. Referring again to the construction illustrated in Fig. 3, it will be ap parent that the device will be self starting if the divergence of the cone 12 is suiiiciently small, since the valve 20 will open when the pressure at the outlet end of that cone exceeds the pressure P and discharges a portion of the-fluid through the outlet 16 into the chamber 19. After a flow of fluid has been established through the chamber 5, the pressure p in that chamber decreases and consequently both the weight of the fluid entrained and the pressure exerted against the walls of the truncated cone 12 decrease. These conditions cause the velocity of the fluid at the outlet end of the nozzle 4 to increase, and consequently, increases the-velocity of the fluid at the inlet end of the mixing cone. The compression effected in the truncated cone 1'2 consequently diminishes and the velocity available at the outlet of this cone and at the entrance of the truncated cone 13 increases in proportion.

If the ratio of the cross sectional are-.rof the outlets of the truncated cones 12 and 13 is sufficiently close to 1, all of the fluid traversing the cone 19. Will be delivered to and pass through the cone 13 prior to the time that Working conditions have been attained in the ejector which would exist, or tend to exist, if the cone 12 only were employed. As soon as all the fluid delivered by the nozzle 12 is capable of traversing the nozzle 13 and of being compressed in that nozzle, the valve 20 will close and the fluid will be exhausted from the nozzle 13 into the chamber 19 by raising the valve 21. As the flow of fluid continues through the alined nozzles, the pressure 7) in the chamber 5 continues to decrease and the velocity of the fluid continues to increase.

' mal working conditions have been established, the. valve will close and all of the fluid. traversing the alined nozzles, will be discharged through the divergent nozzle 23.

The starting operation is thus accomplished step by step throughout the convcrgent cones 12. 13 and 14 and all the fluid traversing the chamber 5 is first discharged through the valve '20 and, after the alve '20 is closed. through the valve 21 and finally through the nozzle 23. If. during the starting operation, the velocity, available at the outlet of any one of the convergent cones. is too low to cause the fluid to pam through the nextsucceeding cone, that is. if the apparatus is badly proportioned the clack valve communicating with the discharge end of the cone discharging the fluid will not be closed and it will be necemary to decrease the convergence oi the next succeeding cone in order that the appara: as may be made to operate correctly.

The operation of starting this ejector has been found by experience to be absolutely automatic. It has also been found by expariment that an ejector similar to the one illustrated which is capable of starting itself perfectly and with which a ratio of compres greater than 20 can be obtained,

P ceases to be self starting when the clack valves are weighted to their seats. It is to be understood that the apparatus disclosed in Fig. 3 is merely by way of example, and that the truncated cones may be replaced by passages. of any form, provided that the cm sectional areas gradually decrease. The openings along the length of the series of convergent cones or passages may be of any suitable form so long as each opening communicates with a space maintained at the pressure P, through a valved passage, the valve of which is capable of opening in response to a slight presure and of aflordingda large delivery area for the passage of What I claim is:

1. An e ectcr device for compressible fluids. comprising an admission nozzle for motive Bali. a mixing cone receiving fluid from said nozzle and having a lateral dis charge aperture formed therein at a point intermediate its ends for discharging excess fluid during the operation of starting the sion ' device, and a divergent nozzle communicating with the outlet of said mixing cone; the outlet of said dischargepassagecommunicating with the region into which said diffuser discharges.

2. An ejector device for compressible fluids, comprising an admission nozzle for motive fluid, a combined convergent divergent tube communicating with the source of fluid to be ejected receiving motive fluid from said nozzle and having lateral discharge pasages intermediate its ends the outlets of which communicate with the region into which the combined tube dischar 3. fif mmhination in an ejector, an admission nozzle for motive fluid, a mixing cone communicatin therewith, means for discharging flui from said cone along its length during the operation of starting said ejector and a receiving chamber extending the entire length of said cone and in free communication with the outlet thereof.

4. In combination in an e ector, an admis sion nozzle for motive fluid, a mixing cone communicating thereivith, means responsive to variations of fluid ressure within said cone for discharging. uid from said cone at points along its length during the operation of starting the ejector and a receiving chamber extending the entire length of said cone and in free communication with the outlet thereof.

5. In combination in an ejector, an admission nozzle for motive fluid, a mixing cone commu'hicating therewith provided with apertures located at points along its length; and means for successively opening and clos ing said apertures during the operation of starting said ejector and a receiving chamber extending the entire length of said cone and in free communication with the outlet thereof.

6. In combination in an ejector, an admission nozzle for motive fluid, a. mixing'cone provided with apertures located along its length, valves operated by the fluid pressure within said cone for o and cl said apertures during the operation of starting said ejector and a receiving chamber in -free communication with said apertures and the outlet of said cone.

7. In an ejector, an admimion nozzle for motive fluid, a mixing cone communicating therewith and provided with a series of apertures arranged lengthwise the walls of the cone, a corresponding series of normally closed non-return valves controlling said apertures so that the presure within said cone cannot exceed the pressure exterior thereto an appreciable amount and a recei ing chamber surrounding said cone and in ,firee communication with said apertures 8. In an ejector. an admision nozzle for motive fluid, means for entraining the fluid to be exhausted, a receiving chamber, a mixing cone located in said receiving chamber and provided with a series of apertures aralong the cone and in commum cation with the entire chamber, and a. corresponding series 0 normally closed non-return wolves controlling said aperturessothattheprissureint-he cone cannot exceed ,the pressure in the receiver chamber by any appreciable amount.

9. In an ejector dperated'by elastic fluid, an admission nozzle. for o ting fluid, means for entraining the flui to be exhausted, a mixing cone communicating with said nozzle and a series of truncated .cones as to rovide a' clearance space between the 0 et of one cone and the inlet of the next mu cone, normally closednon-return valves controlling the delivery of fluid through said clearance and a common recel' 'vmg' chamber for X of said clearance spaces surrounding said cone.

10. In an ejector operated by elastic fluid, an admision node for operating fluid,

means for entraining the fluid to be exhausted, a mixing cone comprising a series of truncated cones so arranged as to provide a clearance space between the outlet of one cone and the inlet of the next succeedim cone, a receiver chamber surrounding sci cone and in free communication with the outlet of the ejector, assages connecting said clearance ace vi the receiver chambet, and norma y closed non-return valves controlling said passages so that the fluid can pass through said clearance space and passages into said receiver chamber when the pressure in said receiver chamber is appreciably less than the pressure in said mixing cone.

In testimony whereof, I have hereunto subscribed my name this 13th day of September, 1910.

MAURICE LEBLANC.

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