US1502478A - Air ejector - Google Patents

Description

July 22', 1924.

v D. W.v R. MORGAN AIR EJECTOE Fiied July 25. 1923 INVENTOR ATTORNEY Patented duly ZZ, 1924.

SYLVANIA.

" f 1,502,478 PATENT oFFIc.E,-f-

DAVID W. R. MORGAN, OF SWABTHMORE, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE .ELECTRIC AND MANUFACTUBENG COMPANY, JA. CGR'PQEATION, OF PENN- AIR EJECTOR..

Application filed July 25,

To all whom t may concern.'

Be it known that I, DAVID W7. R. MORGAN, a citizen of the United States, and a resident of Swarthmore, in the county of Delaware and State of Pennsylvania, have inventeda new and useful Improvement in Air Fjectors, of which the following is a specification.

My invention relates to ejectors and particularly to that class of ejectors employed for exhausting non-condensable fluids from condensers, and it has for an object the pro duction of a two-stage ejector' apparatus of the character designated which shall be simple in construction and which shall operate with a high degree of economy in steam consumption. It is a further object of my invention to provide an ejector apparatus in which the heat of the gases passing therethrough, the heat of the steam operating the ejectors and the water condensed from these fluids is conserved and delivered to the boiler.

A still furtherobject of my invention is to reduce the temperature and specific volume of the non-condensable gases prior to their delivery to the second stage of the ejector and thereby reduce the amount of motive fluid required to operate the ejector.

These and other objects of my invention, which will be manifest in the further description thereof, are set forth 'rn the fol* lowing specification and illustrated in the accompanying drawing in which Fig. l is a diagrammatic view of a condenser system constructed in accordance with my invention; Fig. 2 is a sectional view of a preferred embodiment of my invention; Fig 3 is a sectional view taken on the line III-III of Fig. 2; and Fig. 4l is a sectional view taken on the line IVe-IV of Fig. 2. j

The advantage gained by expanding steam in turbines to a high vacuum at the exhaust has imposed added duties upon the condensing apparatus of power plants utilizing turbines as prime mo'vers, and especially upon the air-removal apparatus of such plants, since the vacuum pressures, which it is practicable to utilize in low pressure turbine plants, are, to a large extent, determined by the efficiency of the air removal apparatus.

rlhe type of air removal apparatus frequently employed at the present time consists of a two-stage steam jet ejector ap- 1923. Serial No. 653,783.

the motive steam condensed in the second Y stage cooler is conveyed to the feed tank. In apparatus of this type, the mixed air and vapor in the second-stage of the ejector is at a temperature somewhat in excess of that of the heated condensate, ,and consequently has a relatively high specific volume.

By my invention it is possible to transmit substantially all the heat of'condensation of the'motive steam to the circulating condensate and at the same time reduce the emperature and specific volume of the air and vapor prior to their delivery to the second-stage of the ejector. This result I accomplish by interposing between thelirst and second stages of the ejector a combined auxiliary condenser and cooler having three compartments consisting of a first-stage condenser, a cooler, and a second-stage con denser. The first-stage ejector discharges into the lirst-stage condenser wherein the separation of the air from the vapor and the condensation of the latter is elfected. The air is then delivered'to the cooler wherein its temperature and specific volume are considerably reduced prior to its delivery to the second-stage ejector. The second-stage ejector in turn discharges into the secondstage condenser wherein the separation of the air from the motive steam is effected, and the airis vented to the atmosphere. The cooling medium for the flrst-stagecondenser is condensate from the main condenser, which having absorbed heat from the air and condensation of the steam used as motive fluid in the iirst-stage of the ejector, is conveyed to the condensing tubes of the second-stage condenser; The pressures within the second-stage condenser being approXimately atmospheric, which corresponding temperature is ,relativelyhigher than` that within the first-stage condenser, the circulating or cooling condensate is successively heated by being conveyed inV series through the cooling tubes ofthe first and second "stage auxiliary condensers, after Which it is returned to the feed tank. The cooling medium for the cooler is extraneous Water'of. a temperature relatively lower than' that'orp the condensate', Vand it therefore absorbs additional heat romthe air.

As steam ej ectors are volumetric displacement pumps, the amount of motive steam required is proportionate tothe voluinekoi huid removed thereby. By subjecting the air. and vapor discharged from the first-stage of the ejector to the condensing action oi. the condensate and 'subsequentlyto the cooling action of Water having a temperature considerably lower than that of the co-ndensate, the specific volume is reduced and a corresponding economy in the amount oi' motive steam required in the second-stage oi" the ejector is effected. This economy in steam consumption will considerably more than compensate for the small amount of heat 'absorbed by the extraneous cooling Water and dissipated thereby. ln lieu of extraneousl Water, make-up feed Water may Vbe employed and a further economy effected.

Furthermore, as the'temperature of the air is reduced, the proportion of vapor contained therein Will be correspondingly lowered.Y I have found, for example, that with a vacuum of 29 inches, ir'. a mixture to be removed by the ejector has a temperature of 650 it contains approximately l pound of vaipor per pound oi" air, WhileV if the temperature of' the mixture is 71o, there are approximately 2 pounds of vapor per pound of dry air. In other Words, approximately 50% more motive steam is required to evacuate the same amount of air and vapor in the Vsecond case than in the iirst.

Referring to the drawings for a more detailed description of my invention, in Fig. l l haveindicated, at 10, a surfacecondenser ofthe conventional type. .lt is to be understood, lio-Wever, that my air ejector Vapparatus is adapted for use with other types of condensers, as for example jet con-- dense-rs. Exhaust steam from a prime mover is admitted tothe condenser through-an inlet opening ll.' Any suitable provision for the removal of air from the condenser mayY be made, as through air discharge openings l2 and valves 13, from whence itis conducted through a conduit 141- to one or more Vfirst-stagev ejectors 15. The air thus de- Vliveredf to the ejector is entrained therein by steam under pressure admitted through the inlet "pipelG and valve 17. --The firststage ejector V may be of any conventional type. It discharges througha diffuser 18 and a conduit 19 to a combined condensing and coolin'g'device 20', which may be constructed as shown or Which may be composed ot tvvo independent heat exchange devices. The combined condensing and cooling device 20 is` composed of a central casting 22 -pipe 57 and valve 58.

having at its upperand lower portions outwardly extending flanges 23 and 24. Se-

` cured to the-se flanges are two tube sheets 25 and 25' which are arranged to receive tubes 27 and 28 which extend through the central chamber. ri. vertically-extending' partition Wall 29 divides the central tube chamber into tivo compartments. These comparti'nents communicate with each other through the opening 30 in the upper port of the partition Wall 29. `Water boxes 32 and are secured in any suitable mann-er to the cas-I ing 22 at the edges olii each of the tube sheets 25 and 26. The . vaterboxes 32 and 33 are provided with vertically-extending portions ot the main condenser 10. As'illustrat'ed,

the conduit 39 leads to a pump 40 which discharges the condensate through la conduit L.L2 to the inlet opening i-S'of the auxiliary condenser 36. The condensate circulates through the tubes 27 as cooling Water and is discharged through the outlet i4 and a conduit to a second-'stage auxiliary condenser as will be hereinafter more fully described..y The cooling Water for the cooler 37 may be taken from any external source which is at a considerably .lower temperature than the condensate of the main condenser, such as boi-ler t'eed make-up or, as shown, be supplied by the main condenser circulating pump 46 through conduits 47 and 4S to the inlet opening 49 of thecooler 87. This extraneous Water circulates through the tubes 28 as cooling Water and is discharged through an outlet 50 and a pipe 52.

The mixed air and steam,\vhich are discharged by the conduit 19', enter the lower portion ot' the auxiliary condenser 36 through an inlet opening 53, and the noncondensable gases or air is discharged therefrom at 30 into the' cooler 37. The air leaves the cooler 37 through theV opening 54 vand is conveyed by the passage V to one or more second-stage ejectors 5G. The air delivered to the second-stage ejector' is entrained therein by steam procured from thesame source as the steam' supplied to the firststage ejector, and admitted through the inlet The second-stage ejector may be of any conventional type. lt kdischarges through a diffuser 59 and a pipe 60 to a second-stage Y auxiliary condenser 62.` This condenser is of the conventional surface type consisting of a central chamber 63 having a nest of cooling tubes 64 therein7 tube sheets 65 and 66 and Water boxes 67 and 68. The mixed air and steam discharged from the second-stage ejector 56 through the ditnser 59 and conduit60, enter thelower portion of the central chamber 63 through the openingy 69. The air is discharged from theV upper portion thereot1 to the atmosphere by means of the opening and a conduit'72. All condensate accumulating within the condensing chamber 63 is removed through the opening 73.

Having thus described the arrangement of an apparatus embodying one form of my invention, the operation thereof is as follows: Exhaust steam is delivered to the condenser 10 through the inlet opening 11. The steam is condensed and collected in the hotwell 33. Steam under pressure supplied to the ejector 15 withdraws the air from the conduit 14- and consequently from the condenser '10, and discharges this mixed steam and air at an increased pressure into the auxiliary condenser 36. Within this condenser, the air is separated trom the steam and moisture and its temperature and specilic volume slightly reduced. The air is then delivered to the cooler 37, in which a considerably lower temperature is maintained, is thoroughly dried and cooled therein and its temperature and specific volume greatly reduced. The dried air is then delivered'throngh the passage 55 to the secondstage ejector 56 wherein the pressure ot the air is raised to a little above atmosphere. The combined steam and air is discharged into the conduit 60, and enters, through the opening 69, the lower portion of the central chamber 63 of the second-stage auxiliary condenser 62. Within this chamber, the steam is condensed and the air removed therefrom. The air passes upwardly through the opening 70 and conduits 72 and is dis- 'charged'to the atmosphere. The condensate accun'iulating in the lower portion of the condensing chamber 63 tlows through the opening 73 to the Jfeed tank.

The cooling water for the rst-stage auxiliary condenser 36 and the second-stage auxiliary condenser 62 may be supplied from the hotwell of the main condenser. Condensate flows from the main condenser hot-f well 38 through the conduit 39 to the pump 40 and is discharged through the conduit 42 to the water box 32. It circulates through the tubes 27 inthe lirst-stage condenser 36 and receives the heat of the air and the steam passing through the first-stage ejector 15. It is then conveyed through the conduit 415 to a water box 67 of the secondstage auxiliary condenser 62. It circulates through the tubes' 64 therein and receives the heat of the air and the steam discharged from the second-stage ejector. charge'pressure of the second-stage ejector being relatively higher than the ytiret-stage ejector, the temperature within the secondstage condenser 62 is proportionately higher thanA the 4temperature within the first-stage The dispassing through the tubes 6ft in the secondstage condenser, the condensate enters the Water box 68 from whence 1t 1s` conveyed to the feed tank.

lt is possible that in some instances, allot the condensate discharged trom the pump 40 would not berequired to circulate as cooling water through the auxiliarycondensers, in whichcase only a portion of the condensate may be utilized and the 'remainder conveyed directly to the feed tank. The cooling water for the cooler 37 may be supplied from any extraneous source of relatively low temperature or may be taken, as illustrated, from the main condenser circulating pump discharge. The main condenser circulating pump discharges Water through the conduit 47 to the main condenser and to the conduit 48. This water enters the water chest 33 and Hows upwardly through the tubes 28 of the cooler 37, and absorbs heat from the air which has been discharged from the first-stage ejector and has been separated from the vapor and steam in the auxiliary condenser 36. The circulating water is discharged at the upper portion of the cooler through the water chest 32 and opening 50 to the conduit 52.

The structure thus far described consists of a separate combined first-stage condenser and cooler and an independent second-stage condenser. A preferred embodiment of my invention is however, shown in Figs. 2, 3 and 4L, in which I' combine all three units into a single structure, thereby greatly reducing the cost of manufacture and the installation space required.

In Figs. 2, 3 and 4t I` show a central chamber 90 having a shell 91 provided with a partition 92 'dividing it into an upper or 'Disposed in an extreme position to the communicating space 98 is an inlet nozzle 99 provided 1n the chamber 95 for the admission of mixed air and steam discharged `from the first-stage ejector, and an outlet nozzle 100 provided in the compartment 96 for the discharge of air therefrom. The f condensate is removed from both the chambers 95 and 96 through the opening 102 disposed in the lower portion of the upper or tiret-stage condensing' and cooling chamber 93. The lower or second-stage condensing chamber v94 is provided with an inlet nozzle and air into the compartment 95.

of each of the tubesheets 108 and 109. Auxiliary water boxes 115 areformed in an upper corner portion of the main water boxes 113 and 114 and are separated therefrom by partition members 116. These auxiliary water boxes 115 communicate with that por-4 tion of the tube nest which is in close proximity to the air outlet nozzle V100 provided in the first-stage condensing and cooling compartment. Inlet and outlet nozzles 117 and 118, which are in communication withthe auxiliary water boxes 115, are provided in the water boxes 113 and 114, respectively,

for the extraneous cooling water. A horizontally-extending partition wall 119 is provided in the water box 113. rlhe water box y 113 is provided with a circulating condensate inlet nozzle 120 and a circulating con-A The operation of the apparatus illustrated in Figs. 2, 3 and 4 is similar to that described above in relation to Fig. 1. The lirst-stage ejector discharges mixed steam This steam and air is vdrawn over the tubes therein and over the tubes in the adjacent compartment 96. Within these chambers the air and condensate are separated, and the air is thoroughly dried and cooled and its specific volume consequently reduced by being compelled to pass over that portion of the tube nest in the vicinity of the outlet nozzle 100, through which portion is being circulated extraneous water of relatively low temperature. The air is removed by the second-stage ejector' through the outlet nozzle 100 and the condensate falls into the bottom of the chamber and is removed by the main condenser through the port 102.

The mixed steam and air discharged from the second-stage ejector enters the lower or second-stage condensing chamber 94 and passes over the tubes therein. The air and condensate are separated, the condensate falls into the lower portion of the chamberv Vthe first-stage condensing chamber and returning through the tubes in the secondstage condensing chamber.V rIhe discharge pressure of the second-stage ejector being relatively higher than thedischarge pressure of the first-stage ejector, the circulating condensate is successively heated by being conveyed in series through the lirst and secondsta e chambers.

he advantages ofmy system of air removal reside in an increased capacity of the air ejectors, in simplicity and low cost ofV production and installation, in economy of steam consumption required to operate the ejector, and in the conservation of' the heat and water in the -air and in the motive steam.

While I Vhave shown my invention in but two forms, it will be obvious to those skilled in, the art that it is not so limited, but is susceptible of various other changesV 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 ory as are specically set forth in the appended claims. Y

What I claim is: 1. In combination with a hight vacuum condenser provided with twoV pumps connected in series for withdrawing air and vapor therefrom, the first of said pumps being a steam-operated ejector pump, a condensing device for absorbing the heat of the steam utilized in the ejector and a cooling device for subsequently reducing the temperature and specific volume of the air and vapor prior-to their delivery to the second pump.

2. In combination with a high vvacuum condenser provided with a two-stage ejector pump operated by steamrfor withdrawing Y of the motive steam utilized therein, and a.

cooling device maintained at a relatively Y lower temperature than the condensing devicev for subsequently reducingthe temperatu-re and specific volume of the air and vapor prior to Atheir delivery to the second stage of the ejector; f

3. In combination with a condenser anda steam-operated ejector `pump having a plui'ality of pressure stages for withdrawing air and vapor therefrom, heat exchange devices of progressively lower temperature interposed between each pressure stage.

4. In combination with a condenser provided with two pumps connected in series for withdrawing air and vapor therefrom, the first of -said pumps being a steam-operated ejector pump, means for subjecting air and vapor discharged from the ejector, first to the condensing action of the water of condensation ofthe condenser, and secondly to the cooling action of water having a relatively lower temperature.

5. In combination with af condenser provided with two air-withdrawal pumps connectedin series, the first of said pumps being a steam-operated ejectorl pump, a combined condensing and cooling chamber interposed between said pumps, a plurality of cooling tubes therein, a portion of said tubes receiving condensate from the condenser and the remaining portion of tubes receiving Water of a relatively lower temperature.

6. In combination with a condenser having means for the removal of air, a steamoperated ejector and a pump connected to the air removal means, an auxiliary condenser for condensing the discharge from the ejector, means for conveying cooling water to the auxiliary condenser, a cooler for reducing the temperature and specific volume of the air prior to its delivery to the pump, and means for conveying cooling water of a relatively low temperature to the cooler.

7. In combination with a condenser having means for the removal of air, a steamoperated ejector and a pump connected in series to the air removal means, an auxiliary condenser for condensing the discharge from the ejector, means for supplying condensate from the main condenser as cooling water to the auxiliary condenser, a cooler for reducing the temperature and specific volume of the air prior to its delivery to the pump, means for conveying cooling water from an extraneous source to the cooler, and means for delivering the steam condensed in the auxiliary condenser and cooler to said condensate supplying means.

8, In combination with a condenser having means for the removal of air, a plurality of ejectors, an auxiliary condenser for each ejector, a cooler in series with each auxiliary condenser with the exception of the condenser which is the last in the series, means connecting the ejectors to the air removal means and in series with each other, means for conveying cooling water to the auxiliary condensers, and means for conveying water of a relatively lower temperature to the coolers.

9. In combination with a condensing compartment provided with a conduit for the removal of air and vapor therefrom, a steam ljet apparatus located withink said conduit and arranged t-o withdraw theair and vapor from the condensing compartment by an ejector action,a heat-exchange apparatus located within said conduit on the discharge' side of the'jet, said heat-exchange apparatushaving a condensing chamberand a cooling chamber, a plurality o-f tubes within the condensing'chamber receivingcondensate from the main condenser, *and a plurality of tubes within the cooling chainber receiving water of a relatively' lower temperature. s y Y i0. ln combination with a condenser having means for the removalof air, a first- -stage ejector connected to the. air removal means, an Yauxiliary condenser into which the first-stage ejector discharges, a. cooler into which the auxiliary vcondenser discharges, a second-stage ejector y'connected to the outlet of the cooler, a second auxiliary condenser into which the second-stage ejector discharges, means for supplying condensate from the main condenser as cooling water to the auxiliary condensers, and means for conveying cooling water of a relatively lower temperature to the cooler.

ll. In a pumping apparatus for a condenser having air removal means, the combination of a first-stage steam ejector connected to the air removal means, an auxiliary condenser into which the first-stage ejector discharges, a cooler into which. the auxiliary condenser discharges, a secondstage steam ejector connected to the outlet of the cooler, a second auxiliary condenser into which the second-stage ejector discharges, means for conveying cooling water from an extraneous source to the cooler, means for supplying in series condensate from the main condenser as cooling water to the `lii'st and second auxiliary condensers, and means for removing condensed motive steam from the auxiliary condensers and the cooler whereby substantially all the heat and water of the steam employed in the ejectors are conserved.

l2. In combination with two steam-operated ejectorpumps connected in series, an air separator having a casing, partition means dividing the casing into a first-stage condensing chamber, a first-stage cooling chamber and a second-stage condensing chamber, means for conveying the gases discharged from the first ejector successively to the condensing action of the first-stage condensing chamber and to the cooling action of the first-stage cooling chamber, means for removing the non-condensable gases from the first-stage cooling chamber tothe second ejector, means for conveying the discharge therefrom to the second-stage condensing chamber, end water boxes and connecting tubes associated with each chamber chambers, whereby the latent heat of condensation of the vapor and steam discharged by the ejectors in transmitted thereto.

13. In combination with two steam-operated ejector pumps connected in series, an vairjseparator having a casing, partition means dividing the casing into a first-stage condensing chamber, a first-stage cooling chamber and a second-stage condensing chamber, communicating means between the rststage condensing chamber and the firststage cooling chamber, each of said chambers having end water boxes and connecting tubes, means for conveying extraneous water to the tubes in the firsts-stage cooling chamber, means for circulating condensate in series through the tubes in the iirst-stage condensing chamber and second-stage condensing chamber, means connecting the discharge nozzle of the first ejector to the first stage condensing chamber, means connecting the suction nozzle oi? the second ejector to the first-stage cooling chamber, means connecting the discharge of the second ejector to the secondstage condensing chamber, air outlet means provided in the second-stage condensing chamber, and condensed motive steam outlet means provided in the casing oi' the irst and second-stage co-ndensing chamber and the iirst-stage cooling chamber.

VIn testimony whereof I have hereunto i subscribed my name this 16th day of July, 1923.

Devin w. n.V MORGAN.

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