US1421842A

US1421842A - Fluid-translating device

Info

Publication number: US1421842A
Application number: US861631A
Authority: US
Inventors: Henry F Schmidt
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1914-09-14
Filing date: 1914-09-14
Publication date: 1922-07-04
Anticipated expiration: 1939-07-04

Description

H. F. SCHMIDT.

FLUID TRANSLATING DEVICE. APPLICATION FILED SEPT. 14, 1914. RENEWED DEC. 30, 1921.

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HOUSE ELECTRIC & MANUFACTURIN SYLVANIA.

G COMPANY, A CORPORATION OF PENN- FLUID-TRANSLATING DEVICE.

Specification of Application filed September 14, 1914, Serial No. 861,631.

7 '0 all whom it may concern:

Be it known that I, HENRY F SCHMIDT, a citizen of the United States, and a resident of Swarthmore, in the county of Delaware and State of Pennsylvania, have made a new'and useful Invention in F luid-Translating Devices, of which the following is a specification.

This invention relates to fluid translating devices and particularly to devices for maintaining a high vacuum in condensers or similar apparatus.

An object of the invention is to produce a fluid translating device of the kinetic type in which means are employed for maintaining the operation of the device substantially practically all varying conditions.

A 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 variations in the quantity of fluid conveyed, thus preventing fluctuations of pressure in either the region of lower or higher pressure.

These and other objects, which will be made apparent to those skilled in the art throughout the description of the invention, are attained by apparatus embodying the features herein described and illustrated in the drawings accompanying and forming a part of this application. 7

The single sheet drawing is a. sectional view of an ejector embodying my invention.

In fluid translating devices such, for example, as ejectors, which employ a stream or jet of fluid as the propelling medium for exhausting fluid from a receptacle, or for transferring fluid from a region of lower to a region of higher pressure, it is necessary to construrt the fluid conducting passage, through which the propelling medium and the medium entrained move in accordance with the f llowing equation: :Y=W. In which Aeqiiulst'ne cross sectional area of the tube at;:l,n v point:.V the velocity of the (-onibinedimediapassingthat point, of the specific-1.volume ofthe combined media; and IV a constant which is equal to the Weight it will be apparent. therefore, that if the Letter P t n iatented July 4, 1922.

Renewed December 30, 1921.

fluid translating device or ejector is designed to attain ahigh degree of compression under one set of operating condition it will not be suitable for starting or for operating under varying conditions. In order, therefore, to render the ejector effective for all varying conditions, it is necessary to vary the dimensions of the fluid conducting or delivering passage in accordance with variations in the conditions, or to effect a change, which is the equivalent of changing the dimensions of the passage, to meet the varying conditions.

In the present application I have illustrated ejectors in which means are employed for varying the effective area of the throat of the fluid delivering passage or diffuser in response to variations in the volume of fluid passing from the region of lower pressure through the diffuser to the outlet, or to the region of higher pressure. It is well known that the pressures existing throughout. the diffuser vary in response to variations in the amount of fluid traversing the diffuser, and it is also well. known that in order to prevent upsetting when the. ejector is operating under light load, or at less than its designed capacity, it is necessary that the pressure at each point along the diffuser remain substantially constant. I therefore provide means which is responsive in its operation to variations in diffuser pressure and which operates to vary the effective throat or the effective area of the diffuser.

The apparatus illustrated. as an embodiment of my invention includes a diffuser 3, to which motive fluid is delivered through a 'main divergent nozzle 4, located axially with relation to the diffuser and to which fluid is also adapted to be delivered through a series of accelerating nozzles 5, which are Serial No. 526,030.

preferablylocated around the main nozzlechamber 6 and is located axially with reference to its corresponding nozzle 5, so that me fluid discharged from the nozzle passes through the diffuser after having passed through the chamber. The difiusers 8 form in eflect a combining chamber for the nozzle 4 and consequently communicate with the difluser 3.

Since, in order to provide an elfective ejector, it is necessary that the product of the are'a of the conducting passage and the velocity of the medium divided by the specific volume of the medium shall equal a constant, which is the weight of medium passing through the ejector in a unit of time; and sinceit is also desirable to maintain a constant pressure in the chamber 8, the specific volume of the medium will therefore .be maintained constant and since the nozzle or nozzles 4 and 5 discharge from a constant initial to a constant final pressure, i. e., the pressure in the chamber 8, it is evident that, in order to maintain a condition of stable e uilibrium in the difl'user, the area of the ifi'user must be varied in direct proportion to the variations in the weight of the medium passing through it.

If the area of the throat of the diifuser is not varied, as above set forth, it is evident that, since the weight of the medium is varying while specific volume of the medium in the chamber 8 remains constant, the velocity of the medium passing through the throat must vary, that is, decrease ifv the weight of medium passing decreases, 'and increase if the weight of medium passing increases. In order to compress or discharge medium from the space 8 through the outlet of the diffuser 3, a definite amount of work per unit weight of medium must be performed; andv this work of compression or translation must be provided by the kinetic energy of the medium "at the entrance of the diffuser. Consequentlyif the velocity of the medium at the entrance .decreases so that the kinetic energy of the medium is less than the; work necessary to move the medium from; the lower to the higher pressure, it is 'apparentfthatthe medium will not .be discharged from the outlet of the diifuser. Un-

der such oondi-tions. the velocity of the medium in; the diffuser will immediately drop to zero,- and" notonly-no work of compression*willfbe-:-accomplished, but fluid will flow frdm Ethel region of higher pressure, or the outlet endfof thedi-fl'user, into the re ion of lower pressure, or the chamber 6. his result is technically known as upsetting, to which reference has been previously made.

The nozzle {is so arranged that it will move to difl'erent positions with relation to the throat 10 of thediffuser 3 for the pur pose of varying the area of the throat 10, and likewise in effect shifting the throat 10 of the diffuser 3 to the throat 12 of the nozzle 4, when the nozzle is in such a position that the divergent portion of the dlfiuser 3 combines with the nozzle to form a single converging, diverging nozzle. It will be understood that under these conditions the nozzle 4 does not actually touch the throat 10 of the diffuser 3, but assumes a position as indicated by the dotted lines in the drawing. This provides a restricted annular opening for-the admission of fluid from the chamber 8.

As illustrated, this is accomplished by providing the nozzle 4 with a tubularfluid delivery passage 13, which is slidably mounted on a body of the ejector and is provided with a piston 14, operating in acyli'nder 15,

formoving it to different longitudinal'positions. One end of the cylinder 15, as for example, above the piston, issubjected to the pressure normally existing in any one of the chambers 6, through a pipe or passage 17, while'the other end, as for example, below the piston 14, is subjected to the pressure normally existing at the throat of the diffuser 3- by connecting that end of the cylinder with the throat by means of a pipe or passage 18. Motion of the piston in response to pressure exerted by the fluid entering throughthepipe 17 is assisted by a coiled spring 19, which, if properly proportioned, will cause the piston to move, in response to fvariations in pressuresin the chamber 6 and at the throat 10, to shift the nozzle 4 insuch a way that the effective area of the throat 10 will vary and will'always be of the size required for the passage of the combined mediaiissuing from the diffusers 8 and the nozzle 12.

As the quantity of medium entering the ports 7 decreases, the amount of work necessary for accelerating the medium decreases until the condition is reached when no medium is entering the ports 7 and consequently no work of acceleration'is required. As the amount of medium entering the ports 7 decreases, the pressure at the throat 10 also decreases with a tendency to equal that existing in the chamber 6, and the nozzle 12 is moved into proximity with the throat 10 of the diffuser 3.- Since this movement of the nozzle is coincident with the diminution of work of acceleration required, I have provided means for employing the motion of the nozzle in controlling the delivery of motive or expelling fluid to the nozzles 5. As illustrated, each nozzle 5 receives motive fluid from the central supply passage, through a separate pipe or passage 22 and through a separate port 23. The delivery of fluid to each port 23 is controlled by the tubular portion 13, which is provided with ports 25, adapted to move into orout of register with the ports 23. With this arrangement, the area of each port 23 will vary with the position of the nozzle 12 in such a manner that just sufiicient motive fluid is delivered to the nozzles 5 to maintain the work vice com risin a diffuser a nozzle for deliverin expelling or motive fluid through the di ser, and means movable in response to variations in the amount of medium to be expelled for varying the effective area of the diffuser. This means is illustrated as a movable plug or coneshaped member which is moved to different positions with relation to the diffuser for the purpose of varying not only the effective area of the diffuser, but also the delivery of expelling fluid through the nozzle. The plug is shown as actuated by a piston which moves in response to variations in pressure conditions within the diffuser.

In my copending application entitled Fluid translating devices, filed September 14, 1914, and serially numbered 861,630, I hjave illustrated and claimed a two stage e ector comprising a main diffuser. a main nozzle'or set of nozzles for delivering ex-- pelling or motive fluid into and through the said diffuser, an auxiliary diffuser and an auxiliary nozzle for delivering expelling or motive fluid into and through the auxiliary diffuser. The inlet 'to the auxiliary diffuser communicates with the source of medium to be expelled, and the auxiliary ejector performs the double function of raising the pressure of the medium to be expelled prior to its delivery to the main diffuser and also of delivering a fluid filler to the main diffuser. The delivery of motive fluid by the auxiliary nozzle is controlled by a movable plug or needle valve. which projects through the steam chamber into the inlet of the nozzle and is movable in response to variations in pressure conditions within the apparatus for the purpose of varying the expansion ratio of the nozzle. j i

In my copending application entitled Fluid translating devices, filed September 14, 1914, and serially numbered 861,633, I

have illustrated and claimed an ejecting de-.

vice including a diffuser communicating with a source of medium to be expelled, and a nozzle for delivering motive or expelling The nozzle is movable toward and away from the diffuser in response to variations in pressure within the ejecting device. This apparatus is essentially a single stage apparatus.

In my copending application entitled Fluid translating devices, filed September 14, 1914, and serially numbered 861,634, I have illustrated and claimed an ejecting device provided with a passage from which a medium is to be exhausted communicating with a diffuser through which the medium from the passage is expelled. A fluid delivery nozzle delivers expelling fiuid through the diffuser and a means responsive to variations in the amount of medium entering the passage is provided for controlling directcommunication between the diffuser and the passage. As illustrated and claimed, a, main or second stage includes a nozzle or set of nozzles which delivers expelling or motive fluid into and through a diffuser. The auxiliary or first. stage is in open communication with the source of medium to be ex pelled and consists of at least one motive fluid nozzle and a diffuser receivingfluid from that nozzle and accomplishing a preliminary compression of the medium prior to its delivery to the main diffuser. The main diffuser is provided with an inlet port or ports for medium to be expelled and this port is adapted to be placed in direct communication with the source of medium to be expelled by means of a passage which in effect bypasses the first or auxiliary stage of the device. This passage is provided with a pressure responsive valve which responds to variations in the amount of medium to be expelled and in this way controls the effective area of the bypass passage or, in other words, the. amount of medium delivered directly from the source to the main diffuser.

'In my copending application entitled Fluid translating devices, filed September 14, 1914, and serially numbered 861,635, I have illustrated, described and claimed an ejecting device pro'vided with a passage for receivin a fluid to be compressed and a means. or partially compressing the fluid from the passage. An ejecting device is arranged to receive the fluid from the compressing means and a means responsive to variations in the amount of fluid entering the passage is provided for controlling the operation of the ejecting device. A first stage is illustrated as directly communicating with the source of medium to be expelled. whereas the second stage not only communicates with the discharge of the first stage, but also communicates with the source of medium to be expelled through. one or more ports formed within the diffuser of that stage.

The first stage consists of a diffuser and one or more nozzles for discharging expelling or motive fluid into and through the diffuser and for thereby entraining medium to be expelled. The second stage includes an annular nozzle and a movable diffuser which is provided with inlet ports at or near its throat. The ports in the diffuser of the second stage communicate with the source of medium to be expelled through a passage which may be termed a bypass passage. Variations in the amount of medium entering the first stage or variation in the amount of medium to be expelled occasion variations variations in the amount of medium to be expelled occasion variatlons 1n the effectlve area of the bypass passage which places the,

second stage of the ejector in direct communication with the source of medium to be expelled. As illustrated and;claimed, the diffuser is also capable of varying the effective area of the nozzles which deliver motive fluid to the second ejector.

. While I have described but one embodiment of my invention, it will be apparent that the drawings are more or less illustrative and that various changes, substitutions, modifications, additions and 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 combination in an apparatus of the character described, a diffuser, a chamber communicating with the diffuser receiving medium to be expelled, a main delivery nozzle for delivering expelling fluid through the diffuser, an accelerating nozzle for deliv:

ering expelling fluid through the diffuser, and means responsive to, variations in the amount of medium entering the chamber for controlling the operation of said main nozzle and the delivery of fluid through said accelerating nozzle. I

2. In combination in an apparatus of the character described, a chamber receiving medium to be ejected, a diffuser communicating therewith through which the medium is ejected, a main nozzle for delivering expelling fluid through the diffuser. an accelcrating nozzle for delivering expelling fluid through said diffuser, and means responsive to variations in the amount of medium to be expelled for moving said main nozzle relatively to said diffuser and for controlling the delivery of fluid through said accelerating nozzle.

3. In combination in an ejector, a diffuser, a main impelling fluiddelivery nozzle alined with the diffuser and acceleratingnozzles around the main nozzle and discharging into the diffuser.

4. In combination in an ejector, a diffuser, a main nozzle for delivering a jet of impelling fluid into the diffuser, and means for delivering accelerating impelling fluid around said main jet and into said diffuser.

5. In combination in an ejector, a diffuser, a chamber receiving fluid to be expelled and communicating with the diffuser, amain nozzle for delivering expelling fluid into and through the diffuser, accelerating nozzles located around the main nozzle for delivering expelling fluid into and through the diffuser, and means responsive to variations in the amount of fluid entering the chamber for controlling the operation of the accelerating nozzles.

6. In combination in an ejector, a diffuser, a chamber receiving fluid to be ejected, a main nozzle for delivering expelling fluid into and through thediffuser, at least one accelerating nozzle operating in conjunction with the main nozzle on fluid entering said chamber and to be ex elled, and means responsive to variations 0 pressure within said chamber for controlling the operation of the main nozzleand of said accelerating nozzle. i

7. In combination in an ejector, a diffuser, a chamber receiving fluid to be ejected, a main nozzle for delivering expelling fluid into and throu h the diffuser, at least one ac celerating nozz le operating in series with the main nozzle on fluid entering said chamber and to be expelled, and means responsive to variations in the amount of fluid to be expelled entering said chamber, for varying the relative positions of the diffuser and the main nozzle and for controlling the delivery of fluid to the accelerating nozzle.

8. In combination in an ejecting device, an accelerating ejector comprising a mixing chamber communicating with a source of fluid to be expelled, a diffuser communicating with said chamber, and a nozzle for expanding and discharging motive fluid at a high velocity into and through said cham:

.ber and diffuser, a second diffuser located at an angle to the first diffuser and into which the I first mentioned. diffuser discharges, and an expansion nozzle for xpanding fluid to the pressure at the in st to the second diffuser and for discharging the fluid so expanded into and through the second diffuser.

9. In combination in an ejecting device, a chamber having an inlet port for medium to be ejected, a diffuser ommunicating with said chamber, a nozzle for discharging expelling fluid through said diffuser, a second diffuser communicating with the outlet of the diffuser, a second nozzle for discharging expelling fluid through said second diffuser, and means for varying the position of said second nozzle with relation to said second-diffuser, in response to variations in pressure within the device.

10. In combination in an ejecting device, a chamber having an inlet port for fluid to be ejected, a diffuser communicating with said chamberfa nozzle for discharging a stream of motive fluid into said diffuser, a second diffuser communicating with the the outlet of the first, a second nozzle for discharging motive fluid into said second diffuser, and means I for shifting the position of the second nozzle relatively to the inlet of the second difl'user.

11. In combination in an ejecting device,

a chamber having an inlet for medium to be expelled, a diffuser communicating with said chamber, a nozzle for discharging fluid through said diffuser, a second diffuser communicating with the first ejector, and means for varying communication between the first and the second diffuser.

12. In combination in' an ejecting device, a' diffuser, a main nozzle axially aligned with'said difl'user for delivering a jetof-impelling fluid into and through the diffuser, acceleratingnozzles located around the main nozzle and discharging into the difluser, and means for controlling the delivery of fluid to the auxiliary nozzles.

13. In combination in an ejecting device, a diffuser, a mainnozzle axially aligned with said difl'user for delivering a jet of impelling fluid into and through the diffuser, accelerating nozzles located around the main nozzle and discharging into the diffuser, and means for controlling the delivery of fluid to the auxiliary nozzles in response to variations inpressure within said dif-- fuser. 14. In combnatlon 1n an- GJGGtIIIgx devlce,

a difluser, a main nozzle axially aligned with, said diffuser for delivering ajet of impelling fluid into and through the diffuser, accelerat- Iing nozzles located around the main nozzle and discharging into the difl'user, and means for controlling the delivery of fluid to the auxiliary nozzles, in response to variations in pressure within said device.

15. In combination in an ejecting device, a main diffuser, 'a main nozzle for dischar ing expelling fluid into and through sa1d diffuser, accelerating nozzles located around' the main nozzle, and discharging into said main difl'user,-and .a separate diffuser be tween each auxiliary nozzle-and the-main 16. In combination in an ejectin device, a main diffuser, a main impelling uid delivery nozzle axially aligned with the diffuser, accelerating nozzles located around said main nozzle and discharging into the main diffuser, a separate diffuser between each accelerating nozzle and the main diffuser, and means for controlling the delivery of expelling fluid to the auxiliary nozzles.

17. In an ejector, a plurality of ejectors operating in parallel on medium to be expelled, each comprising a chamber having an inlet port for fluid to be expelled, a diffuser communicating with said port, and a nozzle for discharging expelling fluid through the diffuser, in combination with a main diffuser with which all the difl'users of said ejectors communicate.

18. In an ejecting device, a plurality of ejectors operating in parallelon medium to be expelled, a diffuser into which said parallel operating ejectors discharge, and means for delivering a jet of expelling fluid into and through said diffuser.

19. In an ejecting device, a diffuser, a main impelling fluid delivery nozzle movable toward and away from said diffuser, and a plurality of. accelerating nozzles around the main nozzle and discharging into said diffuser.

20. In an ejecting device, a diffuser, a main impelling fluid delivery nozzle movable toward and away from said diffuser,

a plurality of accelerating nozzles surround- HENRY F. SCHMIDT.

Witnesses C. W. MoGnnn, E. W. MoCALLIsTER.