USRE15848E - jacobus - Google Patents

Description

May 21.. 1924. Re. 15,848

D. S. JACOBUS STEAM BOILER E CONOMIZER AND METHOD OF OPERATING THE SAME Originl Filed Dec. 8, 1914 2 Sheets-Sheet 1 2 a Q INVEN-TOR. /5%. (km

A TTORNEYS Reiaued May 27, 1924.

NITED STATES.

PATENT, OFF-ICE- DAVID S. JACOBUS, OF JERSEY, CITY, NEW JERSEY, ASSIGNOE 1'0 THE BABCOCK & WILOOX COIPANY, OI BAYONNE, NEW JERSEY, A CORPORATION 01!" NEW JERSEY.

arm-nouns. nconomzaa' AND marl-Ion or orm'rme 'nm em;

Original application filed December 8, i914, semi In. 870,013, which wal amaea as application mes January 3, 1918, Serial 110. 210,213, Patent-Ho. 1,341,218, dated Kay 85, 1880. Application for reissue fled lay 90, 1822. Serial Io. 582,584. Patent llo. 1,442,274 also surrendered."

oxidize or otherwise affect the iron. This is often prevented or minimized by the addition to the water of a neutralizing reagent, such as carbonate of soda or ime, the reagent beingadded' until the matter n solution in the water, contained in the boiler.

accumulates to a point where the amount per gallon of water in the boiler, or the degree of concentration, is such as to effect the desired result. After the reagent: is added it remains in the boiler as it is not steam and the amount of the reagent t at must ,be an evaporated in 'producin plied after the firstreagent is added will only that required to make up forl an to chemical action, or for the amount that 1slost in blowing'down the boiler. The re agent maybe added at intervals to'the boiler,

say once per day orit maybe added con tinuously to the feed water. j Ifadded C01]: 36 tinuously to the feed water the amount r gallbn of feed water may be less than .t at needed to prevent the corrosion, and the. re-- agent, orto be more exact, the resultingcompound. formed through the reagent 40 aj'cti on any impurities in the fecd'water and t -ough the presence of an excess of the reagent over that required to act on the impurities, may be allowed to concentrate in the boiler to the proper point; for example,

the feed water might be treated with twogains of the reagent per gallon which could allowed to concentrate in the boiler to.

twenty grainsper gallon of the reagent and the resulting compounds, and the twenty grains er gallon might give good results where t e two grains per gallon would not.

agaplication is a division of An -economizer cannot be rotected from interior corrosion by the ad ition of a reagent from time to time as in a boiler as the reagentv would pass directly through the economizer with the water; again, should the reagent be addedcontinuously to the feed water, theelements in the feed water cannot be made to concentrate in the economizer in the way that they do in a boiler.

In the numerical example just given, if

twenty grainswe're ineeded to prevent corrosion, it would beI '-necessary to treat the feed water withtwenty grams per gallon to properly protect the economizer, which would make. the treatment more. costly than for a boiler and require the boiler to be blown down at frequent intervals to avoid over-concentration of the contained water.

Distilled water from a condenser, or such .water with only a small amount of raw or make-up'qwater mingled with it,'has been found give trouble through corrosion; air and carbonic acid gas in the feed 'wateradd to, orin some raises may be the sole cause of, corrosion.-

The tendency in modern ower plant practice is toward large size boi erunits and iigh overload's and to maintain a high capacity theboiler must be kept clean on its IIItGIlOIQ'IOthGlWlSG there will be tube difficulties. It'is, therefore, of extreme importance that the boiler feed water shall be of a high'degreefof purity and to meet the present tendency the practice is to cut down the amount ofmake-up water, to avoid the formation of scale in the tubes, and to increase the amount from the hot well, the latter being-distilled water coming from the condensers in the plant. But feed water of the desired purity for the boiler may cause trouble 'through corrosion of the economizer, particularly if it is one of wrought iron or wrought steel.

The purpose of the present invention is to aid in preventing internal and external'corrosion of a two-stage economizer which'may be such as described in 'my Patent 'No. 1',219,320 granted March 13, 1917. In such two-stage "economizers the water passing to the high pressure stage is heated solely by the waste gases. In my present invention I use some of the boiler water to aid in heating the water passing into the high pressure stage, and also introduce elements which aid in preventing corrosionof the tubes of the high premure stage.

My invention will be understood by reference to the accompanying drawings, in which Figure 1 is a side elevation, partly in section, and more or less diagrammatic, of a plant comprising a two-stage economizer; Fig. 2 a diagrammatic lan ,view of two boiler units each having its individual min lin tank; and Fig. 3 a side view'of the in ivi ual mixing tanks. Similar reference numerals indicate similar parts in the several views.

In Fi 1 I have shown a boilerof a standard design in which the numeral 1 designates a bank of inclined generating tubes exended into front and rear headers. The

iler may be fired by any well-known or usual means, a chain rate stoker 2 being indicated. The gases rom the furnace flow through the boiler as indicated by the arrows, 'to a fine 3 leading to the uptake 4. Located in the flue and, as shown, above the boiler, is an economizer com rising a low pressure stage or section 5 an a highpressure stage or sectionv 6. These sections consist of tubes fitted into upper and lower boxes, the high pressure stage composed of wrought iron or wrought steel tubes and headers'and subjected to the action ofthe hottest gases, and the low pressure section composed of cast iron tubes and headers and subjected to the action of the coldest gases.

7 indicates the source of the main supply of water, such as the hot well 7 to which the condensed steam from the plant is run. this being distilled water and practically free of chemical reagents. From the hot well the water is umped by a pumpS through pipe 9 to the ow pressure section of the econo mizer and from said section the'water is delivered through pipe 10 into the upper part of a tank 11. As shown in Fig. 2, the water is delivered to the low pressure sec tions 5 through valved branch connection; 12 leading from the supply pipe 9, and from said sections the water is delivered to a com mon tank 11 through valved branch connections 13 leading to the pipe 10. .Thermometers 14 are placed in the pipes 13, these thermometers being important in the operation of a plant as the valves 15 should be adjusted to give the desired outlet temperature for the low pressure sections of'the econo-' mizers.

The tank 11 to which the hot water is delivered from the low pressure sections .of the economizers, is provided with a series of perforated shelves 16 over which the water is caused to flow. A relief valve 17 is laced at the top of the tank and the air an gases released from the heated water permitted to mode escape therethrough, or the air and gases may be withdrawn through a separate connection 18 to which an e ector or air pump may be connected to maintain thepressure below that of the atmosphere, if desired.

The tank 11 is also provided with a'blowofl' connection 11 for removin any mud or sediment which may collect rpm the feed water. I

From the tank 11 the water is conducted by a pipe 19 to a feed pump 20 by which it is forced through a pipe 21 and valved branch connections 22 into tanks 23, there being one such tank for each boiler., The tanks 23 are preferably so arranged that any mud or sediment in the water will settle to the bottom and can be blown ofi' through the valved connections 24.- The )urpose of the tanks 23 is to mingle the eed water therein with water'from the corresponding boiler, which boiler water contains a certain amount of a chemical reagent which, when,

the water is passed through the high pressure stages of the economizers, will assist in preventing or minimiaing'corrosion of the tubes. As shown. the boiler water is taken from the steam and water drums of each boiler through a pipe 25, having valved branch connections 26, to pump 27 and delivered tohthe. corresponding mingling tank 23 through pipe 28. 'The pumps 2? require a comparatively small amount of'powen as they overcome only .the' difierence in pressure between the boiler and that which the en-- tering-feed water from the pipe 21 produces in the tank 23, which must be suiliciently higher than thatin the boiler to overcome the resistanceof the high pressure stage of 'theiecfonomizer and its connections- The mingled. volume of water from each tank 23 th rough .its outlet pipe 29 to the high pressu c section 6 of the corresponding turned from the boiler to the feed water may be determined.

The pipes 9, 10,;1nd 21 are shown as open- .ended to indicate that they may be used for more than the two boilers shown.

The water from the hot well 7 may be at the temperature of. approximately 80 F.,

mus

' will prevent'sweating on the outside of the said tubes, As the said sections may be made 0 cast iron'tubes which experience has shown will withstand interior corrosion to a greater extent than wrought iron or wrought steel, or this section may be made up of tubes of some other metal and, by using tubes of the right diameter and egroperly spacing them, the heat transfer from the gases to thetubes may be made amaximum'witha minimum dra loss.

By maintainin a proper concentration of the reagent in t e boiler, the water in the several tanks 23 may be made to contain a suflicient amount of the rea ent to prevent addition 0 make up for a lea suc interior corrosion of the tu of. the high pressure section without raising the temperature of the 1 water in said tanks abovea point which ..will interfere ,with the economy of the plant. The amount of the chemical reagent in solution in the boiler ma be graduatedby adding more or less of reagent, either intermittently or continuously, to the respective tanks 23, or by introducin it at the'hot well. The only a reag'git is that necessary to ge, for any, water that may be blown away from the boilers, and

.for any chemical reaction whichmay take wgllgce within the economizers and boilers.

e de of concentration of the water in "the boi or may be determined by the standard :method of" chemical titration, or by measuring the density of the water.

The invention is not, however, limited to C the use of boiler water to which a chemical reagent has been added. In its broader aspect it' includes the return of a certain amount of water from the boiler to the economizer. Where'the water used for making up for leakage and for blowing down the boilers, or what is known as the makeup water, contains in itself the necessary elements to prevent corrosion, no reagent need be added. Whether the make-up water is one which uires the addition of reagents or a water w ich carries the necessary elements to prevent corrosion, the present invention, prevents or lessens the tendenc to corrosion in the'economizer. The folowing example will serve to make my meaning clear. Assume that there is 10 per cent of make-up water containing 8 grains of material per gallon of anature that will tend, to stop the corrosion that occurs with distilled water from the condensers. The mixture of. the make-up water the distilled water from the condensers would contain .73 grains per gallon. If operated in the ordinary way the water passing through the economizer would contain 0.73 ains per gallon of the material that woul tend to stop corrosion, whereas the water contained'in the boiler might be concentrated so as to contain say 100 grains of the same the economizer would amount to about 17 I grains er gallon, a lar er amount than the origina 0.73 grains, eading to a lesser amount of interior corrosion. By practising the invention, therefore, the grains of matter tending to reduce corrosion 1n the numerical case considered is increased more than twenty times over what would exist in ordinary practice.

In operating two or more boilers in which the water after passin through the low pressure sections of t e economizers is mingled in a common tank with water drawn fromall the boilers, care -must be exercised to maintain the amount of concentration in the boilers at about the same point. Should a materially less amount of water, in proportion to the water evaporated, be

returned from one of the boilers to the common mixing tank, the water in the boiler from which the less amount is drawn would soon reach a higher degree of concentration 'than the other boilers. According to the present in"ention,.however, themeecssity of making a close adjustment of the water allowed to flow from each boiler is eliminated for the reason that all of the water "rectly into the. boiler.

From the foregoing description it will be seen that I prevent or minimize corrosionof the high pressure sections of the economizers by eliminating the air and gases from the water, and byadding a'certain amount of water from the boiler containing elements which resistcorrosion.

As before stated, the drawings are diae grammatic. Certain common and wellknown features such as safety valves for the economizers have not been shown. Regulating the supply of make-u water and maintaining the roper level 0 water in the hot well, as well as regulating the water level in the tank 11, maybe carried out in many well-known ways. These are operating features aside from the principles of y invention which I have described.

thence into the corresponding boiler, where by the water drawn from a given boiler is returned to that boiler and corrosion of the economizer minimized through the-action of the corrosion preventing elements and the heat of the boiler water.

2. The method of operating a plurality of mizer at a higher pressure than the firsL sections, thence into the boilers, whereby the water'drawn from a given boiler is returned 'to that boiler, and corrosion of the. economizer minimized through the action of the corrosion preventing elements and the heat of the boiler water. a

3. In combination, a plurality of steam boilers, each having a sectional economizer adapted to be heated by the waste ases, means for delivering, the main supp y of waterto corresponding low pressureeconomizer sections and from the latter to a common tank, individual'tanks for the respective boilers, connections from said common' tank to said individual tanks and from the boilers to the respective individual tanks, andmeans for forcing the mingled volumes from the individual tanks through the high ressuresections of the economizers subeeted to the hottest gases and thence ,into the correspondingboiler. r

4. In combination, a plurality of steam boilers each having a sectional economizer adapted tobe heated by the waste gases,

, sired percentage in the boiler, drawing means Ior conducting the'feed water at a low pressure through corresponding economizer sections, means intermediate the economizer sections to which the heated water is conducted, an individual mingling tank for each boiler, connections from said common tank and from the boilers to said lastnamed tanks, and means for forcing the mingled volumes from the individual tanks through corresponding sections of the economizers at a higher pressure than the first sections and thence into the boilers.

5. In combination, a plurality of steam boilers, each having a sectional economizer adaptedto be heated bv the waste gases, means tor delivering the main supply of water to corresponding low pressure economizer sections and from the latter to a common tank, individual tanks for the respective boilers, connections from said common tank to said individual tanks and from the boilers to the respective individual tanks,

and means for forcingthe mingled volumes from the individual tanks through the high pressure sections of the economizers subjected to the hottest gases and thence into the corresponding boiler, and thermometers in the vconnections leading to and from said individual tanks.

6. In combination, a plurality of steam boilers, each having a sectional economizer adaptedto beheated by the waste ases. means for delivering the main supp y of water'to corresponding low pressure economizer sections and from the latter to a common tank, individual tanks for the respective boilers, connections from said common tank to said individual tanks and from the boilers to the respective individual tanks, means for forcing the mingled volumes from the individual tanks through the high pressure sections of the economizers subjected to the hottest gases and thence into the cor- .responding boiler, and connections for re-.

moving any mu or .sediment which may collect in the individual tanks.

7. The method of operating a boiler and an economizer, whereby the water in the boilermay, bv the presence of a water-treatment chemical in the feed water, be maintained charged with a desired quantity of such chemical in excess of the amount required for the chemical action in the boiler, and the water passing through the economizer may be charged with ,a percentage of the chemical great y in excess of the percentage in the feed water, which consists in providing a feed water charged with a quantity' of the chemical suflieient to give the dewater --from the boiler, anti-a mingling it at boiler pressure with the feed water in an amount suflieient to give the mingled water a percentage of the chemical greatl in excess of the percentage in the fee water alone, feeding the mingled water to .the economizer and delivering the water from the economizer to the boiler.

8. The method of operating a boiler, con-. sisting of withdrawing water containing corrosion-preventing elements from the boiler, mingling it with the feed water for the boiler, feeding the min led volume to an economizer, delivering t e water from the economizer to the boiler, maintainin the water drawn from the boiler under iler ressure from the time it is withdrawn until it is fed to the economizer, and regulating the amount of water taken from the boiler in accordance with the feed entering the same.

9. The method of operatinga plurality of boilers, each connected to a separate economizer, whereby the water in each boiler may, by the presence of a water-treatment chemical in the common feed water supply for all the boilers,'be maintained charged with a desired quantity of such chemical in excess of the amount required for the chemical action in the boiler, and the water passing through each economizer may be charged with a percentage of the chemical greatly in excess of the percentage in the feed water, which consists in providing a common source of supply of feed water at boiler pressure, drawing water from each boiler and-minlin it at boiler pressure with the feed water or t at boiler in an amount sufiicient to give the mingled water a percentage of the chemical contained in the boiler water greatly in excess of the percentage in the feed water alone, feeding the mingled water for each boiler to a corresponding economizer and delivering the water from each economizer to itsboiler, whereby the water drawn from a given boiler is returned to that boiler.

10. The method of operating a boiler and an economizer, whereby the water in the boiler may, by the presence of a water treatment chemical in the feed water, be maintained charged with a desired quantity of such chemical in excess of the amount required for the chemical action in the boiler, and the water passing through the economizer may be charged with a percentage of the chemical greatly in excessof the percentage in-the feed water, which consists in providing a feed water charged with a quantity of the chemical sufiicient to give the desired-percentage in the boiler, drawing water from the boiler and mingling it at boiler pressure with the feed water in an amount suflicient to give the mingled water a percentage of the chemical greatly in excess of the percentage in the feed water alone, and a temperature high enough to prevent external sweating in the economizer, feeding the mingled water to the economizer and delivering the water from the economizer to the boiler.

11. The method of operating a plurality of boilers, each connected to a separate economizer, consisting of withdrawing water containing corrosion-preventing from each boiler. mingling it with feed water from a source common to all the boilers,

feeding the mingled volume for each boiler to a corresponding economizer, delivering the water drawn from the economizer to its boiler, maintaining the water drawn from each boiler under boiler pressure from the time it is withdrawn until it is fed to the economizer, and regulating the amount of water taken from each boiler in accordance with the water fed to that boiler.

212. In combination a plurality of steam boilers each having an economizer arranged to be heated by the waste gases, a. mingling elements tank'for each boiler adapted to maintain the boiler pressure therein, means for maintaining, at boiler pressure, a common feed water supply for all of the boilers, means' for delivering the main supply of water and also water from each boiler under boiler pressure to the corresponding tank, a connection from each tank to the corresponding economizer and a connection from the latter to its boiler and means whereby the amount of wat'er taken from each boiler may be regulated in accordance with the water fed to that boiler.

13. In combination, a steam boilerhaving an economizer arranged to be heated by the waste gases, a mingling tank for the boiler adapted to maintain boiler pressure therein,

means for delivering the main supply of water and also water from the boiler under boiler pressure to the tank, a connection from the tank to the economizer and a connection from the latter to the boiler and means whereby the amount of water taken from the boiler may be regulated in accordance with the water fed to the boiler. 1

DAVID S. J ACOBUS.

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