US 1812275 A
Description (OCR text may contain errors)
June 3.0, 1931.
B. M. THOMPSON 'umuon OF cnmnme 'BOILERS/ Filed June 24. 1927 5 Sheets-Sheet '1 flee-fab M Thompson.
INVENTOR v BYMQ ATTORNEY June 30, 1931. .B. M. THOMPSON 1,812,275
. METHOD OF CLEANING BOILERS Filed June 24, 1927 3 Sheets-Sheet 2 INVENTOR ATTORNEY June 30, 1931. B. M. THOMPSON METHOD OF CLEANING BOILERS Filed June 24, 1 927 3 Sheets-Sheet 5 Ber/0h /1. Thompson.
INVENTOR ATTORNEY Patented Jaa ao', 1 931 p BEBIAE I. THOMPSON, F CHEYENNE, WYOMING METHOD or oLEANmoBomEns Application 111m June .24, 1927. Serial No. 501,268.
(GRAlTTED UNDER THE ACT OF MARCH 3, 1883, AS AMENDED'AI'RIL 30, 1928; 370 0. G. 757) My invention relates broadly to methods of i cleaning boilers ,of stationary or moving 6 sumed by the present methods of cleaning boilers and prevent any director indirect. injury thereto, and the frequent use of which will increase. the efliciency and prolong the useful life of the boiler. With'the methods now in use it has been necessary to remove the side casings of the boilers, thesoot cleaning doors and baflles, butwith my invention no part of the boiler need be removed. The
usual prior method is to manually clean away the soot and solid combustion deposit, that has collected to a thickness of from two to six and more inches ar'oundthe-external surfaces of the lower 'drum of the boiler and between, above and below, the tubes, b means of a brush or other instrument. '1 is method is not only expensive but usually consumes several weeks for a complete cleaning of a boiler.
5 But with my methodone man and one apparatus for the practice of said method may clean such boiler'in a day, or two men and two such apparatus, one for each nest of tubes, may accomplish this work in half a day, far better than the same may be otherwise done. Furthermore, from the natural construction of the boiler, it is practically im-- possible. to reach every point around the pipesand clean the combustion deposit therefrom by any manual means heretofore em plo ed 40 Sleam or compressed a1r, with or without sand, 'will not efiiciently remove said 'com bustion deposit; while such sand blast in the hands of other than the most skilled operator is quite likely to unduly wear, or cut through,
4 the boiler 7 tubes, especially where said deposit is of variable thickness, as it usually is, and the difiiculty of distinguishing, under ordinary working conditions, when saiddeposit has been cut'through at any place and wltign such sand is cutting into any boiler tu v Heretofore the custom has always been to keep liquids away from the combustion chambers ofboilers and the parts thereof exposed in such chamber. Such custom obviated liquids injuring and disintegrating the refractory linings of such chambers, as well as corrosion, pitting, deterioration and shortening of the life of the boiler and its metallic parts occasioned heretofore by acid or other formar tions caused by the reaction of said liquid, even though it be water, upon said deposit; but in spite of saidlong custom I have discovered that liquid may be so used without harmful result, and that my methodremoves said deposit before any such injurious reaction may occur, as well as washes the surfaces from which it removes said deposit to insure that no harmful results may occur.
I have likewise discovered that the constituents of said combustion deposit vary with content of water soluble constituents varying from about 3 per cent to about 20 per cent of the mass. All of the constituents that I have found in said deposits are finely divided and intimately commingl-ed in the mass;
Other samples may vary further and include other substances ;and allcontain more or less sulphur and other substances which set up strong reactions, very injurious v to i the area and rate of said absorption; that metal, when associated with water or other like liquid, and which substances are classed above as water soluble.
As a part of or contributing to my invention I have likewise discovered that by creatsaid external stress; that liquid may be applied to said deposit so as to create each of the aforesaid stresses; that when liquid is so applied to said deposit its water soluble constituents in the affected area of said deposit are quickly liquefied and washed out forming a multiplicity of interstices in said area of deposit; that said evacuated interstices form channels for the entrance, and quick transmission of the effects, of said liquid to a, substantial depth throughout said affected area of said deposit; that one of the effects of liquid upon said mass is that its water-absorbent constituents absorb said liquid; that said evacuated interstices increase said absorption expands the water-absorbent constituents of said mass that said expansion sets up internal stresses in said affected area of said mass; that part of said mass is relatively brittle and non-elastic; that said internal stresses may substantially fracture some samples of said mass in the area kept supplied, by said evacuated interstices and otherwise, with said liquid for a sufficiently long period, but that when said affected area is subjected to the external impact of the liquid its fracture is thereby facilitated, as well as assured even when said mass, in whole or in part, may be of such character as may not be ultimately fractured by saidinternal stresses.
I have further discovered that said external stress on said deposit, through the channels of said evacuated liquid filled interstices, transmits said external stress in part to the interior of said mass, where the force of said impacted liquid suddenly accelerates the rate of absorption of the water-absorbent constituents of said mass and thereby substantially increases their expansive stress upon said mass affected; that said impacted liquid also imparts its stress to the non-absorbent constituents of said affected mass and thereby, and otherwise, substantially augments the internal stresses to which said affected area of the mass was subjected before the application of said external stress; that said internally transmitted part of said external stress is usually the first supplement to be applied to said initial internal stress, and the same continues as long as said external impact continues, while said further supplemental internal stress due to said further expansion is the culminating internal stress, that said culmination and said other internal stresses are continued as long as said external stress is applied; that said stresses thus applied, and continued to the extent necessary, readily, quickly and eificiently fracture into relatively small particles that are incapable of being retained upon the round as well as-ang'ular surfaces upon which they were deposited, and which may be readily conveyed by the spent liquid to a collecting point and thence transmitted even by a hose to a place of disposal, all with little manual effort and substantial speed.
In former boiler. cleaning, by a blunt instrument which was frequently used to chipofi' said deposit, man blows were delivered upon the metallic parts of the boiler which tended to crystalize the sameand shorten the life of the boiler; but with my invention substantially no vibrations are produced in the boiler parts and hence no crystallization re sults, or is contributed to, from the use of my invention, as the impact of the liquid produces no injurious vibrations.
In the method I have developed it is only necessary to allow the boiler to cool down and to have the fire box cleaned out when the work of cleaning the boiler may be started.
Further objects of my invention will appear more fully hereinafter as the description of the method is developed.
My invention consists substantially in the method and the various steps associated therewith as will be more fully hereinafter set forth, and finally pointed out in the appended claims.
Reference is to be had to the accompanying drawings forming a part of this specification in which like reference characters indicate corresponding parts throughout the several views and in which:
Figure 1 is a View of one of the many types of apparatus by which my method may be applied to an inverted V-type boiler, which 1s shown partially in section, the right hand nest of tubes 3, drum 1 and wall 5 being each broken away,
Figure 2 is a sectional view of a portion of the shield and the method of mounting the trough upon the boiler,
Figure 3 is a modification thereof;
t Figure 4 is a sectional view of the packing s rip,
Figure 5 is a view of my preferred form of clamping device, v
Figure 6 is a View of thesprayer valve and nozzle,
Figures 7 8, and 9 are views of the tips of the different nozzles that I have used to wash the masses of combustion deposit out of the more inaccessible places around the base of the tubes.
Referring to Figure l, numerals 1 and 2 represent a lower: and upper boiler drum respectively of an inverted V-type water-tube boiler that are connected together by the 5 usual tubes 3. The boiler has been showmm cleaned by scrubbing with steel wool or a wire brush until there is a clean surface along the drum between the tubes and the firebrick.
A large canvas shield is then hung from a point near the upper ends of the tubes '3 and secured at the lower end to the boiler along and upon the polished strip in a manner to be hereinafter described, so that all associat-.
ed parts of said boiler above said strip be come, during the cleaning operation, a part of saidshield. V v
Referring to Figure 2, numeral 6 represents a canvas trough that constitutes the lower portion of the canvas shield above referred to. The lower edge of the canvas shield is clamped within a packing member 7 shown in detail in F' 4. TlllS packing member is placed along the clean strip between the boiler and the firebox and is held rigidly in position by means of clamp 7a shown in detail in Fi 5.
At the lower portion of. the canvas trough are a plurality of outlet tubes 8 that carry,
away the used water and waste material constituting the cleanings from the boiler. The tube or tubes 8 that are unattached to the run-ofi pipe or pipes, that pass through door 4, are plugged as shown at the-left of Figure 1. Referring particularly to Figure 3, I have shown a metal trough 9 to which the canvas shield is secured in any manner. suflicient to insure a water tight connection between the trough and the shield. Upon this trough is mounted a packin strip similar to that to be described with re erence to Figure 4. The mounting -is practically identical with that of thetrough shown in Figure 2; g 7
Referring particularly to Figure 4, the
- packing member consists of a plurality of U-strips 10 between which is clamped one edge of the metal or canvas trough 11 which is firmly held in position by means of bolts 12. Within the channel of the outerU member is a flexible acking strip 13 of rubber or like material. t will thus be seen that when any pressure is exerted against the boiler by the acking member a water tight connec $101118 obtained,
It isto be understood that any clampingnieans that will secure a water tight connection between the packing strip and the boiler is sufiicient. However, I have found that each clamp there is initially pivot 10. It will thus be seen that the with the types of boilers u on which my invention has been tried, a exibly adaptable clamp of the form shown in-Fig'ure 5 iseasily adaptable'to the -varying slopes between the tubes and the boiler lower drums, as well as to the warping tendency of said tubes due to the. high heat and Internal pressure to .which they are subjected.
The clamp consists of two elements 15 and 16, having semicircular grooves near the outer end and adapted to fit varying sizes of tubes. Between the straight ortion of ally mounted a threaded member 17 that carries a threaded screw 18' in its lower end. When the clamping elements, are placed around the tubes 3 said pendent members 17 may each be advantageously radially positioned about their pivotal connections to each of their-respective clamping elements 15 and 16 to properly position their re ctive screws 18 to most efliciently engage t e channels-of U- I I member 10 whereby said screws 18 may, when tightened against member-10,- retain the adjacent edge of shield 6. Theosition and several clamping units may thenbe rigidly clamped in position by means of bolts'p'assed through the holes 19 and 20. Thetip of each screw 18 when placed in the channel of the U member 10 shown in Figure 2, may thereby secure in position the removable shield 6 even when some of the screws 18 inadvertently do not press against the Web of said U- member 10; but in such contingency the rigidity of member 10, between the screws 18 thatdo bind against saidweb, will still exert sufiicient-tension upon the rubber strip 13 to form a water-tight union betweenit and said a cleaned surface of drum 1 even at 1 points where a screw 18 inadvertently should not be exerting tension against the web of member acking 13 may be pressed thus and thereby orma water-tight temporary union with and throughout the length of said cleaned surface of the wall of the boiler drum by advancing the bolt 18 through the member 17 of each clamping unit;
The water deposited scale formed upon the wholly different nature and character than the combustion deposit formed. upon the. ex-
terior surface of said tubes, and other parts of the boiler, which my invention is especially adapted to remove rapidly-and efliciently. v
Said'combustion deposit is far less conductive of heat than the metal forming the sur faces upon which it is deposited, which requires the frequent removal of said deposit to obtain the maximum efficiency essential under the high fuel, labor and apparatus costs.
moves such deposit without injury to, or
impairment of, the boiler parts; the short interior surface of'such boiler tubes. is of a i time during which the boiler need be out of commission for such cleaning; and the lesser cleaning cost and longer life of the boiler being substantially less than the higher fuel cost of, and liabilitydue to, ineflicient operation of the boiler; jointly and severally invite the frequent cleaning of the boiler with my invention.
Liquid at atmospheric temperature, applied as aforesaid, will accomplish the re moval of said deposit/in time, but by increasing said temperature substantially above atmospheric temperature the rate of said removal of said deposit is substantially increased.
In the practice of my invention it has been found that water heated to a temperature of about 190 degrees and placed under a pressure of about 80 pounds per square inch gives satisfactory results when employed with my method which is very quick, efficient and harmless when no water is applied to the refractory linings which are usually in the form of fire-brick work and indurated plastic work which are readily deteriorated thereby. Such work, when wet, requires long periods of the application of a moderate continuous heat to dry out before the same can be efficiently used; and if wet by the waste water, which usually contain sulphurous and other acids, said drying out leaves said acid effects. For this purpose I supply the hot fresh water through a flexible pipe 21 that is led through the access door 4 and terminates/in a sprayer 22. Attached to the sprayer is a nozzle 23 that may have the various tips shown in Figures 6 to 9 to direct the liquid into the more inaccessible places about the tubes.
The liquid is applied by hose 21 to the deposit to be removed, as large an area thereof as may be desired being wetted, considering that the removal by impact of said liquid will cause surplus and splashed liquid to keep adjacent areas of said depositwell wetted. This liquefies the water-soluble constituents of said deposit, as well as causes the absorption and expansion of the water-absorbent constituents of said deposit, and said expansion to create internal stresses in the affected areas of said deposit. The application of further water, usually surplus or splashed liquid, will wash said liquefied constituents of said deposit out of the interstices where they were liquefied and keeps said interstices filled with cleaner liquid which is more readily absorbed by the water-absorbent constituents of said deposit as said cleaner liquid does not tend as much toward stoppage of the pores of said water-absorbent constituents of said deposit.
Where said deposit fills the horizontal and vertical spaces between the tubes 3, as it usually does for substantial areas above drum 1, the nozzle having the opening at .its tip may be manually pressed at a downward angle against the adjacent face of said deposit whereby the heretofore described actions and reactions of absorption, liquefying, washing out, expansion, fracture and washing out of said deposit in a limited area adjacent the tip of said nozzle by the impact ofthe liquid it discharges in the direction of its longitudinal axis, and whereby said nozzle will be quickly imbedded, to the extent of its length, into said deposit with relatively slight manual pressure. By rotating said flat nozzle about half of a turn throughout said operation the area of each hole will be increased. Thereupon, said nozzle may be withdrawn and other holes successively likewise formed until the face of said deposit is honey-combed with such holes, which are formed therein a distance apart dependent upon the apparent absorbent character of said deposit. While adjacent holes are being formed some of the liquid discharged therefrom is replacing to some extent the liquid left in adjacent formed holes, said replacement being cleaner and more readily absorbent liquid.
While said deposit is being thus honeycombed the liquid in the formed holes is being absorbed by the liquid absorbent constituents of said deposit in an area surrounding each hole, said absorption being directly as well as through the interstices evacuated by the liquefied constituents of said deposit in said area. Said absorption causes expansion of said liquid absorbent constituents .of said deposit and internal stresses in said affected area of said deposit.
When said face of said deposit, or any desirable area thereof, has been so honeycombed, a nozzle, preferably with lateral openings either 25, 26 or 27, is then successively inserted into such formed holes, preferably in the order of their formation, and rotated back and forth about a half turn throughout said insertion and removal, whereby the laterally impacted preferably hot liquid will rapidly complete the disruptive action, initiated by said expansion, and wash out the fragments of said deposit in said affected area progressively as said nozzle is so moved throughout the extent of each of said holes. I have found that a nozzle with an opening only at its, point will accomplish this work, but it requires a longer time, and the holes must be spaced closer together.
Some of the impacted liquid will be projected above the upper layer of tubes 3 and onto shield 30 when said nozzle breaks through the upper surface of said deposit; as well as when moistening, and then impact ing water upon, the deposit upon said upper layer of tubes 3. Such liquid as is not absorbed by said deposit on shield 30 will drain down said shield. Said liquid not absorbed by said deposit on tubes 3 will. drain dcwn the upper surface thereof forming pools in the depressions therein. Such drained liq- 'said deposit, in a layer thinning toward,
and in spots near, its top, causing said shield 30, over each .nest' of tubes 3 to become overheated in the areas occupied by said deposit. Such overheating tends to weaken and buckle shield 30, as well as to ignite any'oil that may drip, or dustthat may collect, upon theierterior surface thereof, and to thus enif turean danger the vessel or structure containing such boiler. Said tendencies are obviated by the removal of said deposit atfrequent intervals, which removal in invention also most economically and e ciently accomplishes concurrently with the removal of said deposit from each of the nests of tubes 3. y
In m invention said shield not only causes t e impacted liquid from said nozzle,
n'ecessa to moisten, wash out, expand,'fracwash 'ofi said daposit therefrom, to
be drained, with :the slu onto the lower portions of the shield whiclr-I form of a part of water drum 1, and the supplemental I -.per
' functions as the temporary shield 6 which I attach thereto but. said shield 30 serves .the further function of catching and draining, ultimately into said shield 6, said liquid accidentally as well a'snecessarily proj V above the uplayer of each tube nest 3 in the operatlon of cleaning the boiler. I 7
It is therefore .a parent that said shield 6 exible supplemental and J --tem orary removable lower portion of, and is 0 smaller area than, the'much greater area of shield afl'orded in my invention by the permanent shield 30, removable shield 6 and the surface of drum 1 between the adjacent 1 edges of said shields 6 and 30; and that my invention causes andrequires said shield 30 and said surface of drum 1 -to seryethe aforesaid additional functions foreign to their normal uses, and in violation of the heretofore 'revailmg custom of'keeping liquid from t e fireside of boilers with their usual refractory material and the metal arts which are usually pitted, corroded an deteriorated heretofore by acid reactions caused by the wetting of combustion deposits thereon.
Thus in my invention, inadvertent or accidenta diversion of the liquid impacting possible dischar ables a spareboiler to be cleaned whilethe' nozzle occasions no. injury to the refractory linings, when present, as said members 30, 1 and 6 function together as a shield of such ample" proportions'as to catch practically all of said nozzle. This envessel is at sea, or even during a storm, without wetting or the refractory fining by such moisture. By its flexible construction said shield also prevents injury to said refractory material in placing-or removing said shield 6, which also prevents in ury to the operator or o raters who may be thrown ofi their balance lfy the motion of the and against shield 6 and its edges.
The nozzle may be moved closer ferent shapes as well as characters of said deposit, and, when the most eflicient distance or angle of impactis not apparent to the op- ,erator'from initial inspectlon, the operators observance of theefi'ectof the impact on a given area will enable him to change the distance or angle of impact, when required, to
obtain the quicker fracture 'of said deposit.
vessel 'to, or fartherfrom, as well as'atany angle to,saiddeposit to obtain the best results with dif- When continuous impact upon one area does not readily produce fractureof the thus im- 'pacted area the operator should change said lmpact to successive impacts upon sald and some other area of said deposit, and each of said successive impacts upon the same area may beat a different angle or distance, as such successive impact stresses .will more readily fracture certain characters of sucli deposit. Also, some areas. of such deposit will rmgleire, for quickest fracture that each impact commenced at one distance or 1e and continued at progressively different stancw or angles.
The liquid deflected from'other impacts usually furnishes ample washing of the surfaces from which said deposit as been removed, but when it is observed that'any such surface is insufliciently washed it may then be impacted and washed directly by said nozzle' discharge.
It will also belnoted that in my invention one of the fundamental purposes is to apply and impact the liquid in whole, or in substantial part, from such direction that the deposit, to which said liquid to be applied and impacted, lies between the applying and impacting nozzle and one of the shield rtions 1 and 30 so that such, or like, flir ed .inetallic parts of the boiler as thus receive :Sflld hqmd will not be injured thereby, and whereby the parts liable to such injury or impairment need receive 'none of said liquid; and that said flexible removable shield 6, or its eqgizalenhgay recggle only the dram' tie tere.man racti nonecessa"- met or deflected ry any splashing of sai liquid from said shield 6 onto the refractory lining.
1m acted liquid, to avoid- Practically every different design of boiler will require a different apparatus in order to carry out my invention in its cleaning. It was necessary to overcome existing long established custom and prejudice against the use of liquid on the fire-side of boilers, and to develop my method of cleaning the same independent of any type of apparatus for its execution.
The nozzle shown in Figure 6 is that of the diamond type 24 that is used for all direct work. The nozzle shown in Figure 7 has the diamond type point 2a with a plurality of side slots 25 directing the liquid from the sides of the nozzle.
The nozzle shown in Figure 8 is similar to the one shown in Figure 6 except that one of the sides of the diamond point is sheared off on one side, as at 26, to direct the flow of liquid to one side. Also in the sides of the nozzle tube are a plurality of holes 27 that serve the same purpose as the side slots shown in Figure 7. The nozzle shown in Figure 9 is open ended and is used for direct washing of the larger surfaces between the boiler tubes.
Each of the nozzles is formed of tubing,
4 the sides of which are flattened throughout the major portion of its length, as shown in Figure 6, in order to readily introduce the nozzle, to the extent of its flattened length, into the horizontal as well as vertical spaces between the tubes 3 of each tube nest, as well as to obtain a greater volume of liquid flowing at high velocity in a flattened stream than would be obtainable from a round nozzle of a size readily introducable into said spaces.
Said flat stream of liquid, ejected by said flat nozzle, may be sprayed over a. given area quicker, when the long axis of said stream is substantially parallel with the surface to be wetted thereby, than by a round stream,
of said limited size, while its greater volume of discharge of impact liquid substantially lessens the time in which said deposit may be moistened, liquefied in part and washed out, absorb, expand, disrupted and washed away by said impacted liquid.
Said combustible deposit soon forms in constant use of the boiler and in thicknesses varying from two to more than six inches, especially over the drums 1 and lower part of each nest of tubes 3, where, before my invention about ninety per cent of the failure of such tubes occurred. a
The speed and ease with which my invention cleans a boiler invites its frequent use and which prolongs the efficient life of such boilers from one to two years longer tha when my invention is not used.
The method that I have found most efficient is to allow the boilers to cool and have the fire removed from the fire box. As soon as the temperature of the fire box has lowered sufiiciently to permit an operator to work therein, the shield and trough are inserted through the access door. A strip is then cleaned along the lower drum 1 of the boiler just above the sloping top of the fire-brick wall 5 and below-the tubes 3; and the trough is mounted, with one edge in contact with said cleaned strip, in the manner above described forming a water tight connection between the boiler and the packing member. The shield is then hungfrom the upper ends of the tubes.
After the shield and the trough have been secured in position and the liquid or water conduit is led through the access door. The operator then works from above the shield and inserts the nozzle between the tubes and turns on the water. Beginning near the top of each tube he follows the spaces between the tubes down to a point in close proximity to the lower boiler drum 1. By the use of this hot fresh water, I have found that the deposits that collect upon the tubes and more particularly that which solidifies into a compact mass near the base of the tubes of the boiler 1 is disintegrated to a suflicient fineness to be carried from around and between the tubes into a trough and through the outlet conduits.
I have tried many kinds of shields,-but said flexible lower removable shield 6 has been found most efiicient, enables the operative or o eratives to work expeditiously and with sa ety in the close quarters where the same must be used, and especially when, to expedite the work, a separate shield 6 and one or more additional operatives are simultaneously employed for each nest of tubes 3, wherein, as well as in the use of but one shield,
such flexible shield 6 yields readily to, and
may be displaced conveniently by, the bodies of the operatives at points where the same is not then being used as a liquid and sludge shield. Said temporary displacements of said shields 6 afford ample working space for the operatives and the nozzles and their hose, besides affording as safe gangway for the operatives substantially the whole area between the upwardly-converging water-tubes 3, and contact with said flexible shields 6 affords the operators timely warning that harder substances are being approached.
An unflexible and unyielding shield 6 could not be employed without sacrificing 'the' aforesaid advantages, and must be made in small sections, to get them into and out of time.
By this method it will be seen that by applying hot water under pressure in the manner above described that sections of a boiler may be thoroughly cleaned-in an operation that consumes very little timein comparison with that necessary for cleaning'thesame boiler by the methods and apparat'us'heretofore used. This substantial saving of time Y that a boiler must be out of commission while being cleaned is of material commercial value, and in war time said value is accentuated. The facility with which my invention enables a spare boiler to be cleaned whileits vesselv is in operation, even in a storm, further enhances-its advantages.
It will be'understoodthat the above descri tion andaccompanying drawings compre 'end only the general and preferred em- 'bodiment' of my invention and that minor de- 201,267, I c aim theapparatus herein dis-v tail changes'in the steps of the method or their sequence may be made within the scope of the appended claims without sacrificing any of the advantages of my invention.-
In my 00- nding application, Serial No.
closed by'which may be practiced the method herein claimed. v. v
The invention herein described may be manufactured and used by or for the Government of the United States for governmental pur' oses without the payment tome of any.roya ty thereon or therefor.
Having thus described my invention what I claim is as follows: v 1. The method of cleaning boiler tubes which includes the steps of washing the solid deposits therefrom by impacting a heated li uid thereon at an angle and preventing said liquid from contacting parts that might be damaged'thereby.
2. The method of cleaning boiler tubes which includes the steps of washing the solid deposits therefrom by means of a heated solvent liquid under pressure impactin thereon in a volume sufiicient to accomp ish the removal of the deposits without forming harmful reactions between said deposit and liquid, and preventing the washingeliquid from contacting parts that might aged thereby.
3. In the operation of cleaningthe combustion deposit from boiler parts, the method 'includingrthelfollowing steps introducmg liquid under pressureinto thefire-sideof a boiler. applying said liquid to said deposit and obtaining a reaction therefrom, impacting further liquid upon portions of the deposit to which liquid had been applied, and preventing the liquid from contacting parts that might be damaged'thereby.
4. In the operation of cleaning the combustion'deposit from boiler parts, the method including the following ste, s; introducing 1i uid under pressure intoit e fire-side of a bo1ler, applying said liquid successively to relatively small areas of said surfaces to be cleaned, and keeping said liquidfrom contact aged thereby.
with such associated partsas may injured in the method thereof consistingof expandingfthe expansible constituents of said de-. v
posit and keeping the expanding agency fromcontacting parts'that might be dam- '7. In the'operationof cleaning vthe combustion deposit from boilerparts, the steps in the method thereof consisting of expanding the expansible constituents ofzsaid deposit successively in relatively small 'areasof said deposit, successively impacting-said expanded areas, and keeping the expanding and impacting-agencies from contact with theassociate'd portions of the boiler liable to be injured thereby.
8. In. the operati the method'thereof consisting of creating an internal stress in sai d deposit. subjecting the stressed deposit to an externalstress by substantially impacting the same with a. ;]'etof the medium creating said internal stress, and maintaining said medium out of contact vwith other parts of the boiler liableto be impaired thereby,
9. In the operation of cleaning the combustion deposit from boiler, parts, the step.
in the method thereof consisting of successively creating an'internal stress in said deposit, successively subjecting the stressed deposit to external stresses, and keeping thestressing agency from contact with associated portions ofthe' boiler liable to be injured thereby.
10. In the operation of cleaning the combustion'deposit from boiler parts. the steps in the method-thereof consisting of applying liquid toandexpanding the absorbent conon of cleaning the com-f bustion deposit from boiler parts. the steps in stituents of said deposit, impgctingtheex panded deposit withfurther liquiduntil said 1 deposit is disintegrated, keeping the applied and impacted spent liquid from contact with associatedboilernpartsliable to be injured thereby, and removing thespent liquidand sludge from the boiler. p.
.11. In the operation of'cleaning the combustion deposit from boiler parts, the steps in the method thereof consisting of manually cleaning a part of the boiler below-parts to be cleaned, applying a liquid shield to said part, and applying liquid to said parts to be cleaned.
12. In the operation of cleaning the combustion deposit from boiler parts, the steps in the methodthereof consisting of applying a liquid shield below parts to be cleaned,- applying liquid under pressure to the deposit to be cleaned from such direction that said deposit lies between the liquid to be applied and said shield, whereby said shield may receive substantiall no direct application of said pressure liquid? BERIAH M. THOMPSON.