US1299283A - Feeding water to boilers. - Google Patents

Description

R. W. ANDREWS.

FEEDING WATER T0 BOILERS.

'APPLICATION-HLEQ Nov. 8.1915.

Patented Apr. 1,1919.

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R. W. ANDREWS.

' FEEDING WATER T0 BOILERS.

' APPLICATION FILED NOV. 8.195.

Patented Apr. 1, 1919,

ROGER w. 'airnzaEws, or ERIE, r

STATE-S PATENT oEE cE 9 I mwsYLvANIA, assienon 'ro NORTHERN EQUIEME .iCOMPANY, OF-ERIE, PENNSYLVANIA, ACORPORATION OF PENNSYLVANIA.

EEEnme WATER TO'VIBQIILEBS.

Erie, in the county'of Erie and statejof Pennsylvania, have" invented" certain new and usefulilmprovements in Feeding Water t Boilers, ofwhichthefollowing is a specificatiom.

paratus r aconaeuing the flow of water to oilers, and" this application is a continuation eta-portion of my copending applica -tion,'Seria 1 No. 793,159, filed Oct. 3, 1913. i

1 valve-capacities are-required, the tendency Y friction 'ofrest in the stufiing boxes, the in- It has also been found inl practice that, as boilericapacities increase and increased feed of thevalve'sstol stick and jerk, due to the creased. mass 'and other causes, increases to "such an extent as to-fintroduce serious disad "vantages." One purpose "of this invention is to reduce materially these disadvantages, by --feeding:the water-to the boiler through two closed While. anotheris substantially fully- Tor. more valves,'therebyreducing thecapac- .ityof each valvemat erially; semewhat according to the number used, and thus re 1 ducing the undesirable efi'ect of the sticking and jerking tendency of each materially.

. I At the same time .the'methodof feeding is such that the valves may be arranged so to act, ordinarily, successively rather than simultaneously, ,one being substantially open, so that simultaneously sticking of the valves is not. likely to oeeu' 4 refinements are introduced more and more into boiler practieefm ore refined methods" I ,of control of the feed water are desiredthan' 40. I of control. Hence a further object of this is possible by the use of the ordinary systems invention is to increase the. sensitiveness of the ,possible adjustments of the feed-water control and thus to increase the possible re- .finements in practice; This result is obtained by the'use of specially designed feed- .water valve ports, and bythe use of a pl11-' ralityof feed-water regulators, instead of one as has previously been the practice, so

V I Specification of Letters Patent. Application filed November 8,1915. .Seria1No.' 60,4 55.

particular 'load is maintained.

- Patented Apr. 1 ,19 19.

"ation of the particular form of-regulator whichI prefer,- and it is'an elevation of a a boiler with such. a regulator attached there- 7 This jingentionrelates tomethods and apsystem of regulators attached thereto which to. Fig. 2 is an elevation of a boiler with :a

embodies the features of my invention Fig.

.3 is a specialfornrof valve used with one of ,the regulators. Fig 4 is a special form of parent upon a consideration of the "drawings attached heretoand the description- 0f the regulators may be used, yet, for the purposes ofv illustrating my invention I prefer the type which is fully shown anddescribed in .my said co-pending application Serial No.

793,159, and which is operated according to the method fully described. in Patent No.

1,148,483, issued to me July 27, 1915. In general the method described said patent consists in producing a continuous and con- 7 stant flow of water into thev boiler so long as the load is constant; in causing the change in inflow to lag behind the change in outflow when the load is changing, but to gradually become equal to.,the outflow when the It has also been foundin practice that as load becomes constant no matter what the load may-be; so that for every different load, so long as the load is constant, a different constant water levelcorresponding to the By "this method heat energy is stored in the boiler during decreasing and light loads; and by carrying out this method in a definite unvarying and dependable manner the hazards incident to boiler use are decreased and the capacity and'the economy of the boiler are materially increased. 9

Although my invention consists in the use of two or more regulators on the same boiler,

yet,'in order to fully explain the operation of the regulatorsl have shown in Fig. 1 a single regulator such as is shown in my said eopending application, andthe operat1on of -Wlll0l1 is as follows: The boiler is indicated by the reference number-'4, The normal or jtedline 6 and the maximum permissible "waterlevel by the dotted line 7.. .The feed-' fwater regulator in this instance comprises an expansion tube 8 mounted on the sup- I connected to the boiler at or below the miniarm 18 of a second lever '19.

ports 9 and 10, which are fixed in any'suitable manner to the T-base 11. The base 11 is supported in any suitable manner in such a wayas to bring the central portion of the operative portion of the expansion tube 8 in substantially the same horizontal plane as the normal water level in the'boiler; the lower end of the operative portion ofthe expansion tube at about the same elevation as the minimum permissible water level, and the upper end of the operative portion of the expansion tube at about the same level as the maximum permissiblewater level.

Pivoted to the upper end of the support 10' by means of the pin 13, or in any other suitable manner, is a lever 15; Theupper' end of the expansion tube 8 is pivoted at the point 12 to. theshort armbf the lever 15; and connected to the outer end of the long armof the lever is any suitable member, such as a rod 17, which sup orts a long he lever 19 is adapted to operate the feed water valve 20 of the supply pipe 21. Pressure may be applied to the water in the supply. pipe in any suitable manner. A weight 14 eliminates at all times any loose play in theconnection between the expansion tube 8 andthe lever 19, and also causes the valve to operate, when allowed to do so, by the contraction of the expansion tube 8.

The location of he up er end of the expansiontube 8, with re erence to the fulcrum 13 of the lever 15, may be adjusted by meansotnuts 16; and the relation of the opening of thej-valve 20 to the outer end of the long arm of the lever 15 may be adjusted by means of nuts 23. Braces 26.fixed to the base 11 prevent buckling of the expansion tube. A consideration of the apparatus described will showthat, as the expansion tube expands, the outer end of the long arm of the'lever 15 will be raised, the. weighted arm of the lever 19 will be raised and the valve 20 will be opened. v

The lower end of the expansion tube Sis mum permissible 'water level of the boiler by means of the pipe 27 5 and the upperend of the expansion tube is connected to the boiler at or above the maximum permissible water level by means of the pipes 28 and 29; so that water from the boiler can pass freely into the lower end of the expansion tube, and

steam from the boiler can pass freely intothe upper end of the expansion tube. As a consequence of this manner of connecting tube 8 to the boiler, the elevation of the I y the dotted line 5, the minimum permissible water level is indicated by the dot-' water in the tube will depend upon the ele-- vation of the water in the boiler; and the upper end of the tube which contains steam will be at substantially the same temperature as the steam in the boilerfwhile the lower end of the tube'which containswater will be at a lower temperature. Even ture as the steam, yet it" will rapidly radiate heat and cool 'to a lower temperature; and

thoughthewater 'whenfiit enters the tube v 7 maybe of substantially the same tempera.

as there is no material interchange of the water in the tube and in the boiler, the water in the tube will necessarily be substantially at all times somewhat materially 'l'owerin temperature than the water or the steaminv the boiler. A

Now, it is evident, that under theseplrcum'stances, as the water level inthe boiler varies, the amount of the water in the, tube will vary correspondingly and the tube will. expand or contract. The valve 20 will then be opened more or less and more or less water willpass into the boiler, otfsetting more or less the "tendenc of the waterlevel in the boiler'to vary. here will thus be a tendency to maintainuni form the elevation of the water level. However, by the use of an expansion tube of proper length or coeflicient of thermal expansion, or by suitable levers or valve ports, or in any other suitable manner,-the variations in the valve openings due to changes in lengths of the expansion tube may be suflicientlyslight,

so that in case of a heavy load on theboller the inflow of water will be less than the consumption of water, and the water in thewater andthewater will rise,

Hence, by the-use of this regulator, it will be found that, not .only' is there a continuous feed to' the boiler at all times when the boiler is under load, but, instead of the variations in feed-beingcoincident andjequal vto the variations 'in steam requirements,

there is a predetermined amount of lag in the variations in feed which relieves the boiler attimes of heavy loads and allows the storage of heat energy during periods of light loads; The arrangement is also such that in case of a very light' load or no load, the feed valve will be nearly or entirely closed, and when heavy loads are long continued or excessive the inflow becomes equal to the outflow, and suflicient water is thereby insured. In fact, at any time when the load becomes constant, whether light, heavy or intermediate, the level will become con- 'stant at a polnt depending upon the amount of load, each load on the boiler having its corresponding water level.

'- The boiler casing 32 has mounted tliereon'in an ordinary mannera cross drum'33. The

boiler is fed by. means ofthe pipes 34 and," 135 controlled respectively by the regulators tracted, and valve 39'will therefore be nearly 36 and 37 acting respectively on. valves 38 and 39. The regulators, in this instance,

are opeiftively connected to "the drum through the water columns 40 and 41'by ,means ofthe pipes 42," 43, 44 and .45.

By the use of this system, it is evident that the inflow will be afiected by the water level at each end of the drum; and that the end of the drum having the lower "water level will receive the greater inflow "of water, a and hence the levelswill tend to become more uniform.

In the application to a boilerofkthetwo f:

regulators, as hereinshown, I prefer to arrange the apparatus so that one of the regulators holds its valve'wicle open during substantially. all of the time that the water level is below the average, and the other regulatorholds, its valve closed duringlsubstanti'ally all of the time that the water level is above the aver'age.- 3 To produce this re sult l mount the e'xpansi'ble tube 36 Fig." 5

so that the upper end of the operative portion of the tube is substantially'at thesame elevation as the maximum waterlevel, which is indicated by line 47 "Fig. 5, and the lower end of the operative-portion of the tube is a little below the average water level which isindicated by line 48, and I mount the tube 37 so thatits lower end is substantially at the same elevation. asthe minimum desired vater level, indicated byline 49, and its upper end is a little above-the average water level. 5 The'operation of the system is as follows:-

When theboiler iscarrying an average. constant load, the water-level in the boilerwill be at line 48, tube 37 will be nearly full of water, and it willtherefore be cool and conclosed. Tube36'will be substantially full of steam, and it will therefore be expanded,

and valve 38 will be open nearlyto its maximumeXt-ent. So long as there is no change in theamount of steam used there will-be.

no material change in the amount :01 water 'in the 'bOile'rQand the valves will be unchanged. If, however, the water level lowers a mat'erial amount because of greater load on the boiler, or otherwise, valve 38 tube 37 upon valve 39. If, on the other hand, the water level should ri'se materially abov the average water level valve 39 would close entirely, and the entire control of the I water level will depend upon tube. 36 and its corresponding valve 38.

,It will thus be seen that, ordinarily, at

water levels .somewhat below the average, theentire control of the inflow depends upon theactionof tube 37; aand,.*ordinarily, at 7 water levels somewhat above the average: the entire control vdependsupon the act of tube-36. As aconsequence during thef'greater o'rtion of the time one valve. only is]- operated andthe undesirableefli'ects due to the sticking and jerking of onelarge valve are reduced-by the use of two, valves each substan- 75, tially only one-halfas lar e as one largeone i would necessarily "be. I it is desirable to -reduce to" a minimum" the disadvantage of the simultaneous jerking of the valves the range of the simultaneous action'of the two regulators 'may' -be substantially eliminated by lowering one regulator tu'be entirely be-. low and raising the other one entirely above the average water level; On the other hand if it is desired to reduce the unequal dis tribution of the water in the boilerthe simultaneous action ,of the two valves may be materially increased; and,.in fact, if desired, may be substantially continuous, by placing the two regulatorsatsubstantially the same elevation. j

As hereinabove suggested, another object ofmy invention is to increase the possibilities of greater refinement in the feeding of water to'boilers, and-one application of my invention to produce this result is as follows: Asis ex'plained hereinabove the action of the regulator, by suitable arrangements and adjustments, will lag behind the changes in the level of the waterin the boiler, so as to cause the level of the water to .sink as the load increases, or to as the load decreases, within certain maximum andminimum limits. It is evident that with a single regulator the amount of lag or the time of the 'lagwill not vary materially at difl'erent water levels. In other words the lag of a single regulator would be substan- V tially the same, with a large load and low ,water level as with a light load and high water level. In practicehowever it is sometimes desirable to reduce the time or the rate "oflag with large loads on the. boiler belowthe time or rate with small loads on the f fi'bOllGI'." ()ne reason for this is becausethe 115 danger from variations in water levels is j 1 greater with a large consumption'of steam than with a small consumption of steam. Withmy system, it willbeapparent that this may be readily cared for, as it is necessary 1 only to change the structures or the arrangements of the regulators so that the a regulator controlling the variations during times of heavy loads will have a'lag-corre. spending to that desired for a heavy load, 125 while the regulator controlling the variations during times of light loads will have a diiierent lagbutone such as is desired'at such times, j i

To produce; this result I haye, as

indi- 13c cated by Fig. 5, shown the expansible tube 37 more nearly horizontal than tube 36 and somewhat'longer, so that it will be more sensitive to variations in water levels, and hence will more quickly respondto such variations in its action on valve 39. To further assist in this I have shown the leverage between the tube 37 and. the valve 39 materially greater than is the case with the leverage between tube 36. and-valve 38. Because of this also the action of the regulator 37 is more sensitive and the lag in time and the lag in rate f,lIlfl0W with reference to the changes in outflow will .be reduced. It-will readily be understood, that other similar variations or refinements may be taken [care of by the use of more thantwo regulators.

'Other refinements with reference to the relative inflow and outflow of the boiler, or of the relation of the water level therein to the load on the'boiler, are sometimes desired.

. I have made further provision in my system I I for such refinements in the following manner: Ordinarily therate of inflow through a valve is substantially proportional to the valve opening. Although any suitable valve may be used, yet I prefer, for this particular refinement in feeding. boilers, valve 38- of which, Fig. .3 shows an enlarged cross section. From this, it is evident, that the flow.

throughthe valve ports will be substantially proportional to the distance the valve cylinder is moved from its seating position, as the "ports have parallel sides so that the opening therethrough is proportional to the length.

I With such a valve the lag of the inflow with reference to changes in level will be substantially the same for all positions of the valve cylinder, as this lag will depend only upon the lag of the movement'of the cylin-z der,-and hence will depend only upon-the leverage and other features of the regulator which would affect the opening substantially uniformly at whatever position the cylinder might be.

However, various means may be used for controlling the inflow in a manner unlike the variatlons of the valve movement, and in a manner unlike the variations in the expansion or contraction of the. expansion tube. I prefer in order to produce this result to vary theshapes of the ports of the'feed water valves. As indicated in Fig. 4, which is an enlarged cross section of valve 39, the ports of the valve do not have parallel sides; so

that the inflow through the ports is not in proportion to the distance of the cylinder from its seat. As a consequence of the spe- I cial form of ports shown, the flowthrough the ports will increase at a greater rate than the rate in which the cylinder is moved I from its sea-t. By the use of this valve to control the flow of water through pipe 35 it is evident-that the inflow due to this valve willvary with reference to variations in the water level in a manner unlike the variations due to valve 38 which has ports with parallel sides. As a consequence of this special arrangement of the regulator tubes hereinabove described, the inflow of water while.

.thewater is materially lowerjthan the average, so that regulator 37 is operating, willincrease at a rate materially greater than the rate at which the valve is opening. One ob ect of'this specific arrangementis to be sure of a suflicient inflow when thelconsump- .tion of steam is great and the level of water in the boiler'is low. At the same time while the load is light and-regulator 36 is effective in controlling the flow the lag inthe inflow will be greater, and the inflow will be subvalve. It is of course understood, however,

that any suitable form of' valve or valve ports may be used, and I do not wish to be confined to the particular form herein-described,

Also it may be desired to maintain-the elevation of the water level in someportions of'the boiler somewhat unlike the elevations in other portions. In this illustration of my "stantially proportional to the opening of the invention I have'shown valve 39 and pipe 35 larger respectively than valve 38 and pipe.

34. As a consequence the water level. adjacent the inletof pipe35 will besomewhat higher than that adjacent the inlet of pipe 34 when both regulators are in full operation. As the water level rises, however, and valve 39 closes the waterlevel will become more nearly uniform throughout; and, if properly adjusted, during the average load on the boiler the water level will be substantially uniform. As the water rises still higher however, and valve 39 closes entirely,

the water level adjacent the inlet of-p'ipe 34 will have a somewhat higher elevation than that adjacent the other end ofthe dru-m. So that, in general, withlow levels and heavy loads the-water level adjacent the right hand end of the drum will be'higher, and during light loadsand high water levels the water level adjacent the left hand end of the drum will be higher. It is evident from'the forc going that, by suitably positioning and adj usting the regulators'and properly selecting the sizes of the jfeed pipes and the valves, the relative elevations of the water levels adj acent the inlets may be varied asd esired;

' Figs. 6,7, 8, show, diagrammatically, the relation of the inflow of water to the water level in the particular system which I have selected be if controlledby regulator alone; and in Fig. 8 the curve 52, shows therel'ation as con-' trolled by the tworegulators-in the manner hereinabove described. For instance the dotted prolongation of the straight portion' of curve. 52 shows the effect of regulating '36, and the total flowat-a water level elevation of two inches is the sum of the'effects of 'thetwo regulators.- .The curvesshown are not intended to be definite, but

are merely suggestive; and it is evident that,

by various modificationsin the structure and adjustments of the regulators, the relation of the inflow to the water levels might be varied indefinitely.

Although I have described with much particularity the specific feed-water regulator system which I prefer, yet I-wish it understood that other types and forms of feed constant, in causing the rate of change of the inflow to lag behind the rate of change of the outflow while the outflow varies, and in cansing the amount of said lag at certain water levels to be unlike the amount at other levels.

2. A method of feeding water to boilers consisting in causing the inflow to substantially equal theyoutflow while the load is constant, in causing the rate of change of the inflow to lag behind the rate of change of the outflow while the outflow varies. in causing the relation of the inflow to the outflow to be alwaysthe same under similar load conditions, and in causing the amount of said lag at certain water levels to be unlike the amount at other levels.

3. A method of feeding water to boilers consisting in causing the inflow to substantially equal the outflow while the load is constant, but in causing the change in rate of inflow to lag behind the change in rate of the outflow when the rate of outflow 5. A method of feeding water to boilers consisting in causing the changein rate of the inflow to lag' behind the change in rate of the outflow when" the rate of outflowvaries, and in causing the-amount ofsaid lag to vary as the load varies.

at two remote points, at,a rate depending upon the water level in the boiler attwo points located a material distance apart-f and in causing the rate of change of the total amount of water passing into the boiler to lag behind therate of change of the amount passing out of the boiler.

7. A boiler feed water system comprising two regulators, each of, said regulators being connected to said boiler above and be low the average water level. one of said regu lators being at a higher elevation than the other regulator.

8.'-The combination of aboiler and two feed-water regulators: each. of said regulators being operatively connected to said boiler; each of said regulators comprising an expansion tube, each of said tubes being inclined at an angle to the horizontal plane, and one ofsaid angles being greater than the other.

9. A combination of a boiler, two water regulators, two-valves and two-levers; each of said regulators being operatively connected to said boiler and to one of said valves;.-each of said levers operatively connecting one of said regulators with one of said valves; the leverage of one of said levers being greater than the other.

' 10. A method of feeding water to boilers consisting-in causing the rate of change of the inflow to lag'behind the rate of change of the outflow while the outflow varies, and

in'causing the amount of said lag at light loads to be greater than the amount of said lag at heavier loads.

.11. A method of feeding water to boilers consisting in causing the rate of change of the inflow to lag behind the rate of change of the outflow while the outflow varies, and

in causing the amount of said lag togradually increase as the load decreases.

' 12. A method of feeding water to boilers consisting in causing the rate of inflow to the boiler with reference to the rate of outflow therefrom to gradually increase as the outflow increases.

, In testimony whereof, I hereunto set my hand in the presence of two witnesses.

- ROGER w. ANDREWS.

In the presence of E. W. NICK, V. V. VEENSOHOTEN.

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