US1927649A - Steam generator - Google Patents

Description

Sent. 19, 1933.

W. G. NOACK STEAM GENERATOR Filed May 20. 1930 5w 2 g g T" g E 6 5b il Inventor Patented Sept. 19, 1933 1,927,649 STEAM GENERATOR Walter Gustav Noack, Baden, Switzerland, as-- signor to Aktiengesellsohaft Brown Boveri & Cie, Baden, Switzerland, a joint stock company of Switzerland Application f in Germany 14 Claims.

This invention relates to steam generators, and it has particularrelation to injection steam generators as described, for instance, in my 00- pending application, Serial No. 268,493 which matured into Patent 1,817,419. In such steam generators a small quantity of steam, called exciter steam, is superheated and applied to water, for instance, by injection of one medium into the other, to evaporate the water by the superheat of the admitted steam and producing thereby an enlarged quantity of steam; the soobtained larger quantity of steam is again superheated and utilized to convert a further quan' tity of water into steam, thus further increasing the amount of available steam; and this process is successively repeated untilthe required quantity of steam is generated.

' Among the objects of the present invention is the provision of an improved steam generator of the foregoing type having special arrangements for securing eflicient and desirable operating conditions at no load, as well as high load operation.

The foregoing and other objects of the invention will be apparent from the following description, reference being made to the accompanying drawing which illustrates diagrammatically one embodiment of the invention.

As shown in the drawing, the multi-stage injection steam generator comprises a ,reservoir 4 holding water in the bottom part and a,

quantity of steam under pressure in the top part. Feed Water is suitably supplied to the reservoir 4 by a feed water line 5 through a water pree heater 5a which preheats the water before it is delivered to the reservoir. Included in the feed water pipe 5 is also a valve 51) actuated by a regulating device which is connected to I the steam space in the reservoir 4 to vary the admission or" feed Water to the reservoir depending on the pressure therein, as will be explained hereafter.

To generate steam a small quantity of steam is drawn by steam pump 6 from reservoir 4 and F forced under pressure through a first superheator 7 into a first vaporizer 8. The vaporizer 8 is supplied with water from the reservoir 4 by, means of a water pump 9 which forces water through a delivery line 11 and discharges it the vaporizer 8 in the form of a spray. The steam from the; superheater 7 and the water from the delivery line 11 are thus brought ,into intimate contaotvaporizing a large quantity of water and producing a 'large quantity 5 of wet steam. Excessive injection water flows May 20, 1930, Serial No. 453,941, and

May 31, 1929 back to the reservoir 4 from the vaporizer 8 through a return line 12. f v

' The increased quantity of wetsteam in vaporizer 8, being under the pressure of the steam pump 6, is forced from the vaporizer 8 through, a second superheater 13, where it is .againsuperheated, into a second vaporizer 14where the superheated steamconverts additional water irom line 11 into steam. This process is' repeated in each of the successive vaporizer vessels 1'? and 18 until the" required quantity of steam is generated inthe last vaporizer 19 iromlwhere the wet steam flows through a main super: heater 21 andfoutlet valve 22 to the steam con: suming devices. lThus, alvery smalllquantityjof excitation steam irom the reservoir 4 is fsufiicient to produce allarge quantity 'oisteam of such pressure as may'bq'desired' The" heat is supplied to thegsuperheater coils 13,: 16, 18, ,21 by the hot combustion gases passing'throughgas duct 3 in whichthejooilsare mounted, the reservoir 4 being outside 'ltheduct. wTo initially start it the operation, an auxiliary boilergl, heated by the hot combustion ,gases in duct 3, is.pro-, vided to produce an initial amount v of steam which is delivered through heatingfcoilfz to the steam space ofreservoir 4 .for starting the v vaporization process in the series of vaporizer stages. 7 The pressure of this excite rv boiler 1 may be made sufiiciently large 'to force the steam flow through the several stages, in which case pump 6 wouldnot be necessarybut operation with a pump .is preferable, because under normal conditions reservoir4 has always enough steam to start operation. For normal operatio'n the steam generated .by the vaporizer stages is made about sufiicient to'supply thenormal load. The reservoir is utilized as a buffer or storer for taking care of excess steam demand or overloads, and of excess steam generation by "the vaporizer stages whenthe steamdemand is below normal. This is eflected by the'provision of a bypass conduit with non-return ;valv e'123 permitting steam flow from the outlet side of the main superheater 21 (before shut-off valve of the superheater 21 and sol-that non-return 110 the pressure in the final superheater 21 will drop below that of the reservoir 4 and the nonreturn valve 24 will be opened by the higher pressure on the reservoir side thereby permitting Wet steam to flow from the reservoir 4 directly through the superheater 21 to the point of consumption.

If the steam consumption decreases, thetotal amount of steam generated will increase the steam pressure in the superheater 21 above that in'the reservoir 4 and the non-return valve 23 will open to permit a return of the excess superheated steam to the water space of reservoir 4 in which it is' condensed. When the steam generator is being shut down by closing valve 22, or when the supply is greatly in excess of the demand, in either of which cases large quantities of steam are returned through the non-return valve 14 to the container 1, an excessivepressure (blowing off) in the latter may be avoided by the supply of excess feed water to the container. Since in comparison with ordinary boilers the container operates with greatly varying water levels, the level of the water in normal'operation, will usually be kept relatively low and when closing down-or during periodsof very low demand a large quantity of feed'w'ater will be introduced which condenses the excess steam, TheeXtra feed water, in the same way as'the normal feed water, is supplied by feed water pipe 5 through'the water preheater 5a in the fiue duct 2 to the container 1. The, admission ofexcess feedwater is automatically regulated by the pressure regulator which controls the feedregulator 5b to supply more water to the container ,1 when a predetermined pressure in the said container is e5:- ceeded. The regulation'of the feed Water in normal operationis effected in the usual manner by a regulator dependent on the alteration of watenlevel in the container.

Although but one embodiment of the present invention has been illustrated and described, it willfbe apparent that various changes and modifications may be made therein without departing from theispirit of theinvention or from the scope of the appendedclaims.

The invention claimed is: 1 1.' In a steam generating installation, a reservoir for holding, preheated water and steam, a

pump connected with said'reservoir to withdraw steam therefrom, a preliminary superheater receiving the steam from said pump, a primary vaporizer receiving the steam from said superheater, a plurality of secondary superheaters, a plurality of secondary Vaporizers, said secondary superheaters and said secondary Vaporizers being connected in series with said-primary Vaporizers, meansconnected with said reservoir for supplying water to all of said Vaporizers, a final superheater receiving and heating the steam from all of said Vaporizers, and means connecting the steam space of said reservoir directly with the inlet side of said final superheater during periods of increased demand for steam.

2. In a steam generating installation, a reservoir for holding preheated water and steam, a

pump connected withsaid reservoir to withdraw steam therefrom, a preliminary superheater re- 'ceiving the steam from said pump, a primary vaporizer receiving the steam from said superheater, a plurality of secondary superheaters, a

plurality of secondary Vaporizers, said secondary superheaters and said secondary Vaporizers being connected in series with said primary vaporizer, means connected with said reservoir for supplying waterto all'of said Vaporizers, a final'superheater receiving and heating the steam from all of said Vaporizers, and means connecting the outlet side of said final superheater directly with the water containing space of said reservoir during periods of decreased demand for steam,

3. In a steam generator, a steam generating circuit including a reservoir for holding proheated water and steam water from the said preheater, a pump connected with said reservoir to withdraw steam therefrom, a preliminary superheater receiving the steam from said pump, a primary vaporizer receiving the steam from said superheater,a plurality of secondary superheaters, a plurality of secondary Vaporizers, said secondary superheaters and said secondary vaporizers beingconnected in series with said primary vaporizers, means connected with said reservoir for supplying water to all of said vaporizers, and a final superheater receiving'and heating the steam from all of said Vaporizers to the temperature desired for use; and a steam supply control circuit including a non-return valve for passing steam from the steam space of said reservoir directly into said final superheater dur ing periods of increased demand for steam, and a non-return valve connecting the outlet side oisaid final superheater directly with the water containing space of said reservoir during periods of decreased demand for steam.

4. In asteam generator system, a reservoir for holding preheated water and steam, a main superheater having an inlet and an outlet, an injection steam vaporizer connected between the steam soaoe of said reservoir and the inlet of said main superheater, said vaporizer comprising a vessel having a water inlet for supplying Water to the vessel, superheater tubes connected between the reservoir and said vessel arranged to superheat steam received from said reservoir and discharge it in superheated condition into the vessel to vaporize water supplied thereto, and a steam outlet for delivering the resultant steam in said vessel into said main superheater, means associated with said reservoir to produce a steam flow'from the reservoir through the vaporizer to the main superheater, generating in the vaporizer additional steam joining said flow, a bypass conduit connecting the steam space of said reservoir to the inlet side of said main superheater, a bypass conduit connecting the water space or" said reservoir to the outlet side of said superheater, and valve means associated with said injection steam vaporizer connected between the steam space of said reservoir and the inlet of said main superheater, said vaporizer comprising a vessel having a water inlet for supplying Water to the vessel, superheater tubes connected between the reservoir and said vessel arranged to superheat steam received from said reservoir and discharge it in superheated condition into the 'vessel to vaporize water supplied theretm and a steam outlet for delivering the resultant steam in said vessel into said main superheater, means associated with said reservoir to produce a steam flow from the reservoir through the vaporizer to the main superheater, generating in thevaporizer additional steam joining said flow, a bypass conduit connecting the'steam space of-s'aid reservoir to the inlet'side of said main superheater including valve means to permit flow of wet steam from the reservoir to the main superhe'ater only in response to lower pressure at the holding preheated water and steam; a main superheater having an inlet and an outlet, an injection steam vaporizer connected between the steam space of said reservoir and the inlet'of said main superheater, said vaporizer comprising a vessel having a water inlet for supplying water to the vessel, superheater tubes connected between the reservoir and said vessel arranged to 'superheat steam received from'said reservoir and i discharge it in superheated condition into the vessel to vaporize water supplied thereto, and a steam outlet for delivering the resultant steam in said vessel into said main superheatenmeans associated with said reservoir to produce asteam flow from the reservoir through the vaporizer to the main superheater, generating in the vaporizer additional steam joining said flow, conduit means including a non-return valve opening in response to decrease of the pressure of the steam supply connecting the steam space of the reservoir to the inletof said superheater to supply and conduit means including a non-return valve opening in response to excess of steam supply connecting the outlet side of the superheater to the water space of the reservoir causing superheated steam to flow from the superheater to the water space of the reservoir." 7

7. In a steam generator system,"a reservoir for holding preheated water and' steam, a mainsuperh'eater having an inlet and an outlet, an injection steam vaporizer connected between the steam space of said reservoir and theinlet of said main superheater, said vaporizer comprising a vessel having a water inlet for supplying water to the vessel, superheater tubes connected .between the reservoir and said vessel arranged to superheat steam received from said reservoir and discharge it in superheated condition into the vessel to vaporize water supplied thereto, and 'a steam outlet for delivering the resultant steam in said vessel into said main superheater, means associated with said reservoir to produce a steam flow from the reservoir through the vaporizer to the main superheater, generating in the vaporizer additional steam joining said flow, and a bypass conduit connecting the water space of said reservoir to the outlet side of said superheater including valve means to permit flow of superheated steam from said superheater to the waterspace of said reservoir only in response to higher pressure at the superheater outlet than a corresponding pressure in said reservoir. H

water space of said resflow from the reservoir through side of said multi-stage vaporizer'than 8. In a steam -generator system,- a reservoirfor holding preheated water and steam; a main sue perheater having andinlet and an outlet, a multistageinjection steam vaporizer connected be- I tween the'stea'm space or said reservoir 'andthe inlet of said main superheater, said vaporizer comprising a plurality of serially arranged-vaporizerstages, each of said stages'comprising a vaporizer vessel having a water inletfor supply- 7 ing water to'the vessel, superheater tubes arranged to superheat received steam and discharge it in superheated condition into the vessel to vaporize water suppliedthereto',anda steam outletfor delivering the resultant steam in said vessel, the steam outlet ofthe vaporizernvessel of each stage being connected-to the inlet of the superheater tubes of the following stage','-means' associated with said reservoir to produce. a steam the successive stages to the main superheater, generatingin each stage additional steam joining saiidflowfa' bypass conduit'connecting the steam space of said reservoir to the inlet side of'said main sup erheater, a bypass conduit connecting the water space of said reservoir to the outlet side of said superheater, and valve means associated with said conduits'arranged" to permit flow of wet steam from the reservoir through its conduit :to the main superheater, and flowN-ofsuperheated steam fromjsaid superheater to the water'space of said reservoir depending on the'pressurecon-' ditions in the system.

9. In a steam generator system',ia,reservoir'for holdingpreheated water and steam, a "main superheater having an inlet and an: outlet, a multi-stage injection steam vaporizer connected between the steam space of said reservoirand the inlet of said main superheater, said vaporizer comprising a plurality of serially arrangedvaporizer stages, each of said stages'comprising a vaporizer vessel having a waterinlet-ior.supply- 1 7 ing water to the vessel, superheater tubes arjranged to superheat received steam and-diswet steam from the reservoir to the superheater,

charge it in superheated condition into the yessel to vaporizewater supplied thereto,iand a steam-outlet for delivering-the resultant steam in said vessel, the steam outlet of the vaporizer vessel of each stage being connected to the inlet of the superheater tubes of 1 the' following stage,

means associated with said' reservoir for normally maintaining a higher at the pressure at the inlet outlet'side thereof to produce a steam -flow from the reservoir through the successive stages to the main superheater, generating i'nfeachstage additional steam" joiningsaid flow, conduit means including a non-return valve opening in response to insufficient steam supply connecting I including a non-return valve opening in response to excess of steam supply connecting'the outlet side of the superheater to the water spaceof the reservoircausing superheated steam to how from the superheater to the water space of the reser:

voir.

for holding preheated water and steam; a main superheater having an inlet and an, outlet, a

10. In a stearn generator-system;- a reservoir multi-stage injection steam vaporizer "connected between the steam space or said'reservoir and the inlet or" said .main superheater, said vapor izer comprising a plurality of serially arranged said reservoir water, to the water inlets of said vaporizer vessels and returning excess water in the vaporizer vessel'to said reservoir, means associated with said reservoir for normally maintaining afhigher pressure atthe inlet side of said multi-stage vaporizer than at the outlet side thereof to produce a steam flow. from the reservoir through the successive stages to the main 1 superheater, generating in each stage additional steam joining said flow, a bypass conduit conmeeting the steam space ofpsaidreservoir to the inlet side of said main superheater including valve means to permit flow of wet steam from the reservoir to the main superheater only in response to lower pressure at the superheater inlet than a corresponding pressure in said reservoir, and a bypass. conduit connecting the Water space of said reservoir to the outlet side of said superheater including valve means to permit now of superheated steam from said superheater to the Water space of said reservoir only in response to higher pressure at the superheater outlet than a corresponding pressure in said reservoir.

11. In a steam generator system, a reservoir for. holding preheated water and steam, a mainsuperheater having an inlet and an outlet, a

, multi-stage injection steam vaporizer connected between the steam space of said reservoir and the inlet of said main superheater, said vapor- .izer comprising a plurality'of serially arranged vaporizer stages, each of said stages comprising avaporizer vessel having a water inlet for supplying water to the vessel, superheater tubes arranged to superheat received steam and discharge it in superheated condition into the vessel to vaporize water supplied thereto, and a steam outlet for delivering the resultant steam in said vessel, the steam outlet of the vaporizer vessel of each stage being connected-to the inlet ofgthe superheater tubes of the following stage,

means associated with said reservoir to produce a steam flow from the reservoir through the successive stages to the main superheater, generating in each stage additional steam joining said how, a bypass conduit connecting the steam space of said reservoir to the inlet side of said main superheater including valve means to per mit flow of Wet steam from the reservoir to the main superheater only in response tolower pressure at the superheater inlet than a corresponding pressure in said reservoir, a bypass conduit connectingthe water space of said reservoir to, the outlet side of said superheater including valve means to permit flow of superheated steam from said superheater to the water space of said reservoir only in response to higher pressure at the superheater outlet than a corresponding pressure in said reservoir, and ashutoff valve controlling the outflow of steam from the outlet side of said superheater to the steam consuming devices for causing steam from the superheater outlet to flow to the water space of 7 the reservoir to heat it up and build up the pressure therein.

7 12. Ina steam generator system, a reservoir for holding preheated water and steam, a main superheater having an vinlet and an outlet, a vmulti-stage injection steam vaporizer connected between the steam space'of said reservoir and the inlet of said main superheater, said vaporizer comprising a plurality of serially arranged vaporizer stages, each of' said stages comprising a vaporizer vessel having a water inlet for supplying water to the vessel, superheater tubes arranged to superheat received steam and discharge it in superheated condition into the vessel to; vaporize water supplied thereto, and a steamoutlet for delivering, the resultant steam in said vessel, the steam outlet of. the vaporizer vessel of each stage being connected to the inlet of g the superheater tubes of the following stage, means asso-- ciated withsaid reservoir for normally maintaining a higher pressure ,at' the inlet side of said multi-stage vaporizer than at theoutlet side thereof to produce a steam flow from the reser voir through the successive stages to the main superheater, generating in each stage additional steamvioining saidflow, a bypass conduit'connecting the steam space of said reservoir to the inlet side ofsaid main superheater including valve means to permit flow of wet steam from the reservoir to the main superheater only in response to lower pressure atthe superheater inlet than'a corresponding pressure in said res V ervoir',-,and a bypass conduit connecting the water space of said reservoir to theoutlet side of said superheater including valve means to permit flow of superheated steam from said superheater to the Water space of said reservoir only inresponse to higher pressure at the super- I heater outlet than a correspondingpressure in said reservoir. 1 13. In a steam generator system, a reservoir for holding preheated water and steam, a main superheater having an inlet and an outlet, a

multi-stage injection steam vaporizer connected between the steam space of saidreservoir and the inlet of said main superheaten said va porizer comprising a plurality of serially arranged vaporizer stages, each of said stages comprising a vaporizer vessel having a water inlet for supplying water, to the vessel, superheater tubes arranged to superheat received steam and discharge it, in superheated condition into the vessel to vaporize water supplied thereto, and .asteam outlet for delivering the result ant steamin said vessel, the steam outlet of the vaporizer ,vessel of each stage being connected to the inlet of the superheater tubes of the following stage, means for supplying from the,

Water space of said reservoir water to the water inlets of said vaporizer vessels, means associated with said reservoir to produce a steam flow from the reservoir throughcthe successivestagesv to the main superheater, generating in each stage additional steam joining said flow, a bypass con duit connecting the steam space of said reservoirto the inlet side of said main superheater including valve means to permit flow of wet steam from the reservoir to the main superheater onlyin response to lower pressure at the superheater inlet than a corresponding pressure in said reservoir, abypass conduit connecting the water space of said reservoir to the outlet side of said superheater including valve means to permit flow of superheated'steam from said superheater to the water space of said reservoir EEO only in response to higher pressure at the super- 7 heater outlet than a corresponding pressure in said reservoir, and means for variably supplying feed water into said'reservoir to condense excess steam flowing from the superheater to said reservoir.

14. In a steam generator system, a reservoir for holding preheated water and steam, a main superheater having an inlet and an outlet, a multi-stage injection steam vaporizer connected between the steam space of said reservoir and the inlet of said main superheater, said vaporizer comprising a plurality of serially arranged va-' porizer stages, each of said stages comprising a vaporizer vessel having a water inlet for supplying water to the vessel, superheater tubes arranged to superheat received steam and discharge it in superheated condition into the vessel to vaporize water supplied thereto, and a steam outlet for delivering the resultant steam in said vessel, the steam outlet of the vaporizer vessel of each stage being connected to the inlet of the superheater tubes of the following stage, means for supplying from the water space of said reservoir water to the water inlets of said vaporizer vessels, means associated with said reservoir to produce a steam flow from the reservoir through the successive stages to the main superheater, generating in each stage additional steam joining said .flow, a bypass conduit connecting the steamspace of said reservoir to the inlet side of said main superheater including valve means to permit flow of wet steam from the reservoir to the main superheater only in response to lower pressure at the superheater inlet than a WALTER GUSTAV NOACK. I

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