US1460045A - Method of and apparatus for compressing fluid - Google Patents

Description

June 26, 1923. 1,460,645 R. SUCZEK METHOD OF AND APPARATUS FOR COMPRESSINGFLUID Original Filed May 13, 1921 xxx; 6' 6- 12 2 14 r 20 J T 2 7: I

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' the nozzle structure,

ROBERT SUCZEK, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO C. H. WHEELER MANUFACTURING arm or PENNSYLVANIA.

COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORA- METHOD OF AND APPARATUS FOR COMPRESSING FLUID.

Application filed May 13, 1921, Serial No. 469,163. Renewed May 9, 1923.

To all whom it may concern:

Be it known that I, Ronnn'r Suoznx, a citizen of the Czecho-Slovak Republic, residing in the city and county of Philadelphia, State of Pennsylvania, have invented certain new and useful Improvements in Methods of and Apparatus for Compressing Fluid, of which the following is a specification.

My invention relates to a method of and apparatus for raising the pressure of or compressing elastic fluid, as gas, such as air, such as steam, or a mixture of gas or vapor, and vapor, by entraining the fluid to be compressed in a jet or jets of motive fluid,

more particularly gas, vapor, or a mixture of them, the mixture of entrained and motive fluids then decreasing in velocity and increasing in pressure, as is characteristic of ejectors or aspirators.

In accordance with my invention, I procure greater efficiency of operation, either in single or multiple stage ejector apparatus, in the sense tion pressures greater amounts of fluid to be compressed are compressed or raised to the desired pressure with less motive fluid.

In ejector apparatus in which the throat area of the nozzle structure is constant and in which the ratio of the throat area of the nozzle structure to the outlet area of the nozzle structure, that is, the expansion ratio of the nozzle structure, is constant, and with a given pressure of motive fluid supplied to the weight or amount of the fluid tobe compressed varies in predetermined way with regard to its initial or suction pressure. Accordingly, such arrangeme-nt is most effective with a given nozzle structure for a given suction pressure or initial pressure of the fluid to be compressed for compressing a maximum weight or amount of fluid. It is desirable, however, that the same ejector apparatus shall be available to compress maximum weight or amount of elastic; fluid with the same nozzle structure under conditions of different suction pressure or initial pressure of the fluid I to be compressed.

For this purpose I change or vary the pressure of the motive fluid supplied to the nozzle structure, whereby greater amounts or weights of fluid may be compressed from certain suction or initial pressures with the that for different or varying sucinvention.

Fig. 3 is a fragmentary sectional view, on enlarged scale, of one of the motive fluid throttling devices.

Fig. 4 is a vertical sectional view,'partly in elevation, of a modified form of apparatus embodying my invention.

Referring first to Fig. 1, ordinates are pounds per hour of the entrained fluid or fluid to be compressed, and abscissee are absolute suction pressures in inches of mercury column. The curve A is a characteristic of a double stage ejector apparatus which may be employed, for example, for maintaining high vacuum in a steam condenser. In the example illustrated the pressure of steam or motive fluid employed upon the nozzle structure in both stages is approximately 125 pounds per square inch. rom an inspection of this curve it is apparent that the curve B is the characteristic for the same ejector apparatus employing, however, motive fluid or steam at 100 pounds pressure as applied to the nozzle structure of the first stage, while the steam pressure applied to the nozzle structure of the second stage is 125 pounds per square inch. characteristic for the case where the motive fluid or steam pressure applied to the nozzle structure of the first stage is 85 pounds per square inch, while, as before, the motive fluid applied to the nozzle structure of the first stage is 125 pounds per square inch.

From a comparison of these characteristics A, B and C, it is apparent that while the curve A corresponds with better performance as to amount of fluid entrained and compressed at higher absolute suction pressures, the characteristics B and C show better performance in the sense ,that greater C is the amounts of fluid are entrained and compressed at the relatively lower suction or initial pressures of the fluid to be entrained and compressed.

To effect the performances illustrated by the above mentioned curves, the motive fluid pressure in the second stage may, in the example discussed, remain substantially constant, while the motive fluid pressures applied to the nozzle structure of the first stage are progressively decreased as the first stage suction pressure decreases. By so decreasing the first stage motive fluid pressures for decreased suction pressures, the efficiency of the ejector apparatus is materially improved in that not only are greater amounts of fluid entrained and compressed, but with less expenditure of motive fluid.

These changes of pressure of motive fluid upon the nozzle structure are effected by employingsuitable motive fluid throttling devices, as nozzles or orifices, or valve structures having known or predetermined settings.

By preference, and in the examples herein illustrated, the means for throttling the motive fluid is a nozzle or orifice of fixed orpredetermined capacity.

Referring to Fig. 2, E and E are ejectors of any suitable types or structures of which E may directly discharge into the ejector E or, as preferred and illustrated, there may intervene between them the interstage condenser C, wherein the motive fluid or other condensable vapors discharged by the ejector E are condensed, leaving only the air or other uncondensable fluid to be delivered to the ejector E to be raised to higher pressure thereby.

For example, the suction chamber 1 of the ejector E may be connected by suitable piping to a steam condenser in which the exhaust steam from any suitable source, as for example, a steam turbine, is to be condensed and in which high vacuum is to be maintained. The ejector is provided with suitable nozzle structure, as one or any suitable number of expansion nozzles N communicating with the steam or motive fluid chamber 2 and directed toward the diffuser or combining tube structure D The motive fluid, as steam, is delivered from any suitable source, as a boiler, not shown, by pipe 3 which, in the example illustrated, has three branches, 4, 5 and 6, provided, respectively, with the cut-off valves 7, 8 and 9. In the pipes 4 and 5 are interpolated, respectively, the nozzles or orifice plates 10 and 11. One of .these, as the nozzle or orifice plate structure 10 of pipe 4, is illustratedon larger scale in Fig. '3, where it will be noted that the plate or member 12 is introduced between neighboring sections of the pipe 4: and is provided with the orifice or nozzle passage 10, of fixed dimensions and allowing generally passage, in the direction of the arrow, at a predetermined motive fluid pressure in the pipe "3, of a predetermined-amount of motive fluid. The second stage ejector E is provided with nozzle structure comprising one or any suitable number of expansion nozzles N communicating with the steam chamber 13, between which and the motive fluid supplypipe 14 are three branches 15, 16 and 17 I rovided, respectively, with the shut-ofl' va ves 18, 19 and 20,. and two of the branches, 15 and 16, being provided, re-' spectively, with orifices or nozzles 21 and 22.

Assuming that the interstage condenser C is absent and that the ejector E discharges more or less directly to the suction chamber of the ejector E with the valves7 and 8 of the first stage and 18 and 19 of the second stage c-losed, and the valves 9 and 20 open, full pressure of the motive fluid is applied to the nozzle structures of both stages."

Further assuming that this motive fluid pressure. is the 'same as applied to both stages through the branches 6 and 17, the ejector will or may have a characteristic resembling the characteristic curve A of Fig. 1. If now it is desired to work at a lower absolute pressure in the suction chamber 1 of the ejector E, the valves 8 and 9 are closed, and the valve 7 opened, whereby there then intervenes between the steam pipe 3 and the steam chamher 2 the nozzle or orifice 10, which accordingly throttles the motive fluid steam so that instead of having, as before, practically 125 pounds pressure upon the steam chamber 2,

the pressure will now be less and will be, for

example, 100 pounds per square inch. Under these conditions, and with valve 20 open and valves 18 and 19 closed, the performance will be of the character indicated by the curve B of Fig. 1, whereby at lower absolute pressures inv the suction chamber l-of the ejector. E greater amounts of air or other fluid entering the suction chamber 1 will be compressed to the desired final pressure at the discharge of the diffuser D of the sec- 0nd stage, with lower steam pressure upon the first stage nozzle structure and consumption of less motive steam. Again, if it is desired to work at still lower absolute pressure in the suction chamber 1, the valve 7 is closed, the valve 9 remains closed, and the valve 8 opened, the valves of the second stage nozzle structure remaining as before. In this case there intervenes between the steam pipe 3 and the steam chamber 2 the second or smaller orifice or nozzle 11, with the result that there exist-s in the steam chamber 2 a pressure of, for example, 85 pounds per squareinch, in which case the performance will be of the character indicated by the curve C, Fig. 1, whereby still less motive fluid pressure is employed, less amount of motive fluid is employed, and relatively greater amount of air or other fluid is entrained and compressed. While with the above described operation the valve 20 of the second stage is open while the valves 18,and 19 are closed, the performance can be still further improved by employing in connection with the second stage the nozzles 21 and 22, which have, as regards the second stage, and as regards the over-all performance of both stages, eifects similar to those above described in connection with Fig. 1. My invention is, however, of more importance in connection with the first stage, since at the discharge of the diffuserD of the first stage the back pressure of the first stage varies with the load or amount of air or fluid to be entrained or compressed, while as regards the second stage the pressure at the discharge of the difl'user D is generally substantially constant.

When any one of the three branches 4, 5 or 6 of the first stage structure is employed, any one of the three branches 15,

16 or 17 of the second stage structure may.

beemployed.

. It willbe further understood as to the first stage. and also as to the second stage, that the branches 6 and 17 may be considered by-passes for the nozzles or orifices 10, 11 and 21, 22. It will be understood, however, that these by-passes may be omitted, and when highest pressure is to be available upon the steam chambers 2 and 13, the nozzles 10, 11 and (or) 21, 22' may be simultaneously in operation.

In general, it is preferred to employ an interstage condenser between the two stages of the ejector apparatus for condensing out from the mixture discharged from the first stage all condensable vapors, as the motive steam and any condensable'vapors in the entrained fluid.

When an interstage condenser is employed between the first and second stage ejectors, the employment of the motive fluid pressure-changing means, particularly of the first stage ejector, is of greater advantage than when no interstage condenser is employed. This is due to the fact that when an interstage condenser is employed, the pressure at the discharge of the first stage ejector varies through a greater range for given variations in the weights or amounts of fluid to be entrained and compressed.

Referring to Fig. 4, there is shown in the first stage an ejectorE, in general of any suitable character, as a tubular ejector, and such, for example, as the ejector E of Fig. 2. In the second stage the ejector E is provided with an annular nozzle N producing a circular sheet or jet of motive fluid which entrains the fluid discharged from the first stage ejector E, and the mixture is delivered into the surrounding annular diffuser D and delivered intothe discharge casing F, from which it is discharged through the port F In this case the ejector E is'provided with the branches 4, 5 and 6, as in Fig. 2.

The, combination of ejector E with ejector E is of the eneral character disclosed in prior Letters l atent of the United States No. 1,282,595. This combination affords a. perfectly stable operation throughout great variations of, load or amounts of fluid to be entrained and compressed and throughout great ranges of change of pressure in the first stage suction chamber 1. However, it is of advantage to apply to the first stage ejector of such combination the means for varyin the motive fluid pressure for obtaining the effects hereinbefore described.

While the second stage ejector E of Fig. 4 is shown as supplied with motive fluid at full boiler pressure, it will be understood that the motive fluid for the second stage nozzle structure N may be similarly throttled, though in general this will not be necessary or of great advantage.

While I have in Figs. 2 and 4 shown two nozzles or orifices between the steam supply and the steam chamber of each stage, it will .be understood that any other suitable number of orifices may be employed.

From the foregoing description it is apparent that while the nozzle structure of ejector apparatus has constant ratio of expansion, that is, the ratio of throat area to outlet area of the nozzle structure is constant, improved performance for different suction pressures is available by suitably changing the pressure of the motive fluid su plied to that nozzle structure.

hile, as illustrated and preferred, orifices or nozzles are employed for effecting changes in-the motive fluid pressure as applied to the nozzle structures, it will be understood that any equivalent means may be employed, as for example, valve structure, if capable of being set-to predetermined positions or openings. It will be understood, of course, that the valves 7, 8, 9 and 18, 19, 20 are ordinary shut-ofl' valves with which it is difficult or impossible to procure any predetermined or proper adjustments for pressure determination.

What I claim is:

1. The method of compressing elastic fluid by elastic motive fluid, which consists in expanding motive fluid into jet formation, entraining thereby the fluid to becompressed, converting the velocity of the mixture into pressure, and controlling the characteristic of the operation by giving to the motive fluid in advance of the aforesaid jet panding motive fluid into jet formation,

. entraining. thereby the fluid to be. compressed, converting the velocity of the mixture into pressure, and controlling the characteristic of the operation by throttling the motive fluid in advance of the aforesaid jet formation to different predetermined degrees.

3. The method of compressing elastic fluid in a plurality of stages, which consists in expanding motive fluld into jet formation, entraining thereby the fluid to be compressed, converting the velocity ofthe mixture into pressure, giving to the motive fluid in. advance of the aforesaid jet formation different definite or predetermined pressures,

expanding in a later stage motive fluid intojet formation, entraining fluid of the afore said mixture thereby, and converting veloc-.

thereby the uncondensed component of said mixture, and converting velocity of the mixture'into pressure.

5. Ejector apparatus comprising expasion nozzle structure, co-operating diffuser structure, means for conveying motive fluid to said nozzle structure, means for diminishing the pressure of said motive fluid to predetermined degree, and means for by passing said last named means.

6. Ejector apparatus comprlsing expansion nozzle structure, co-operating diffuser structure, and a plurality of means for reducing the pressure of the motive fluid delivered to said nozzle structure to different degrees. 1

7. Ejector apparatus comprising expansion nozzle structure, co-operating diffuser structure, meansfor conveying motive fluid to said nozzle structure, means for diminish ing the pressure of said motive fluid to predetermined degree, means for by-passing said last named means, and valve structure for controlling said pressure diminishing means.

8. Plural stage ejector apparatus comprising in each stage nozzle structure and cooperating difl'user structure, and means for throttling to predetermined degree the motive fluid delivered to the nozzle structure of one of said stages.

9. Plural stage ejector apparatus comprising in each stage nozzle structure and cooperating diffuser structure, and means for each stage for throttling the motive fl uid delivered to the nozzle gtructure thereof to predetermined degree;

10. Thecombination with staged ejectors, of interstage condenser structure, and means for throttling to predetermined degree the motive fluid delivered to the nozzle structure of the ejector discharging into said 'condenser structure.

11. The combination with staged ejectors, I

of interstage condenser structure, means for throttling to predetermined degree the motive fluid delivered to the nozzle structure of the ejector dischargin into said condenser structure, and means. or throttling to predetermined degree the motive fluid delivered to the nozzle structure of an ejector receiving the discharge from said condenser structure.

prising a plurality of staged ejectors, interstage condenser structure, and a plurality of means for throttling to different predeter- 'mined'degrees the motive fluid delivered to one of said ejectors.-

l3. Plural stage ejector apparatus com- 12. Pluralstage ejector apparatus comprising a plurality of staged ejectors, interstage condenser structure, and a plurality of means for throttling to different predetermined degrees the motive fluid delivered to the nozzle structure of one of said ejectors discharging into said condenser structure.

14. Ejector apparatus comprising nozzle structure, co-o erating diffuser structure, means for con uctino motive fluid'to said ejector, and a member disposed between said means and said nozzle structure'having an orifice of predetermined area for diminishing the pressure of the motive fluiddelivered to said nozzle structure.

1'5. Ejector apparatus comprising nozzle structure and cooperating diffuser structurgi means for delivering motive fluid to sai ejector, a plurality of throttling members having orifices of diflerent areas, and means for connecting said orifices in operative relation with said nozzle structure.

16. The method of compressing elastic fluid in a plurality of stages, which consists in expanding motive fluid into jet formation, entraining thereby the fluid to be compressed, converting the velocity of the mixture into pressure, expanding in a later stage motive fluidinto jet formation, entraining thereby fluid of'the aforesaid mixture, converting velocity of the resultant mixture into pressure, and changing the characteristic of operation by changing to predetermined pressure said second named motive fluid in advance of said second named jet formation.

17. The method of compressing elastic fluid in a plurality of stages, which consists in expanding motive fluid into jet formation,

entraining thereby the fluid to be com-- pressed, converting the velocity of the mixture into pressure, condensing the condensable component 'of pressure sai said mixture, expanding motive fluid in another stage into jet formation, entraining thereby the uncondensed component of said mixture, converting the" velocity of the resultant mixture into pressure, and changing the characteristic of the operation b changing to predetermined second named motive fluid in advance of said second named jet formation.

18. The method of operating ejector apparatus utilizing expanded elastic motive fluid for compressing elastic fluid, which consists in changing to predetermined extent the pressure of the elastic fluid before expansion in accord with the initial pressure of the elastic fluid to be compressed.

19. The combination wi h ejector apparatus comprising nozzle structure having constant throat area and expansion ratio for expanding elastic motive fluid, and c'o-operating diffuser structure, of means for changing the operatin characteristic comprising means for changmg to predetermined extent the pressure of the motive fluid delivered to said nozzle structure.

20. Plural stage ejector apparatus comprising an ejector, means for changing the pressure of the elastic m'otive fluid delivered to said ejector from one predetermined'pressure to another, and a second ejector to which is delivered fluid by said first named ejector for further compression by said second ejector.

In testimony whereof I have hereunto af- I fixed my signature this 9th day of May, 1921.

- ROBERT SUOZEK.

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