US2438929A - Foam suppressing apparatus - Google Patents

Description

W. B. LEAF FOAM SUPPRESSING APPARATUS April 6, 1948.

Filed April 1 5, 1946 fm/enfor' PVG/ferl B pLeczf HIS HflO/"ngg 'A' Q. l A/* N N mw ww IIIII'Illllllllll'llllAllllll'l'lllllllllll lll ww .ESMQ twiki JL O QM Patented Apr. 6, 1948 Application April 15, 1946, Serial No. 662,166

(Cl. 25h-361)A i lo'lclalims.; l This invention relates to apparatus for suppressing the formation of foam andparticularly to such apparatus for use in locomotiveboilers and similar pressure vessels. i

The present invention is 'ani improvement on the invention vldescribed and claimed` in Patent No'. 2,320,366 issued on June 1, 1943,? to the same inventor. The production of vfoam in boilers is caused by the presence of certain substances dissolved in the water which increase the surface tension. The tendency to produce foam-becomes greater i as the-concentration `of the dissolved substances increasesp Foaming may be reduced by the addition of various chemicals to the boiler water; however, this requires frequent `inspection and servicing. In accordancewith the disclosure oi the above patent, the -formation of a layer'of roam in a boiler is prevented orV minimizedY by arranging a partition below vthe'liquid surface with a plurality oi passages-of-wdecreasing cross section; bubbles rising through the body of liq'-` uid and entering one of thepassages `concurrently are brought together and areiforced tov` join or coalesce bythe narrowing walls ofthe passage.

through thebody of liquid in whichf they are produced. Y

It is another object of this `invention to provide an improved and, rruggedwand easily constructed foamvsuppressing apparatus `for `loco'- rnotive boilers and the like.

It is a further object of this invention to pro vide an improved foam suppressingapparatus for locomotive boilers and-the like,-which` may easily be repaired or replaced.

Further objects andadvantages of this invention will appearmore-iully in the course-of the following description, and the `features of` novelty The larger bubbles thus formed burst` on reaching the surface ofthe liquid and' thus do not collect to form a blanket of `foam. l Thisl method of foam suppression has been ioundeff fective in practice, and .itlis;an object oi thepresent invention to provide'an improvedap-f paratus for suppressing foam I by-forcing bubblesA into coalescing engagement'during theirpassage which characterize the invention will be -pointedl out with particularity in the claims annexed to` and forming a part of this specification.`

For a better understandingof` the invention,

reference may be had to the accompanying draw-- ing in which:

Fig. .1 is a sectional elevation View ofa portionof a locomotive boiler tted with a coalescingapparatus embodying `the invention;

Fig. 2 is a sectional view on theline 242 of Fig. 1; and

Fig. 3 is an 4enlarged perspective view vof a portion of theapparatus of Fig-f1.

As shown in the drawing,- the `locomotive boiler Y `(lll includes a shell I having a steamV dome 2 about an opening i at the top of the shell. f A plurality of retubes i extend longitudinally of the boiler from a lire box 5 to a smoke chest 6 at the for` ward end'of the locomotive. `The boiler is filled with water to -a normal level as indicated by a dot and dash line, the water covering allthe retubesand also extending over a crown sheet 'I at the` top of the iire'box. During the' `operation` `of the locomotive, bubbles of Asteam-brise through the body of liquid, the steam collecting Y inthe space above the water. Steam for operation of `the-locomotive is drawn ofi through the usual dry pipe, indicatedV at and openingwithmr l in .the steam dome 2. i

to :form foamwhen-they reach the surface, -each bubbleretaining a lm of liquid. In" order to i coalesce these bubbles. andA form larger bubbles,4

which will 'tend to `burst andthus not'produce i appreciableifoam, a foarn"suppressor'9`is ar# 1 rangedin. the -body'of liquid above the re tubes i 5. The suppressor. 9 comprises a partitionmem`` ber'supported within thezboiler shell onaplue ralitypiA angle brackets IQ and extending the width offthe shell; The suppressor` partition is constructed of upper and lower layers or members I! and I2, rrespectively, each providing a large number of `inverted troughs or` elongated recesses off inverted `V--shapeclcross section. Each'troughf is opensatthe top and bottom, the v topopeningbeing a narrow slot; it will thus be apparent.l that.` bubbles' rising through the bodyof liquidfand entering a trough tend to be brought together by the narrowing walls of the trough. Inf this manner, the bubbles` are forced into coalescing engagement and larger bubbles :are formed. The bubbles formed in and passing throughthe` lower partition layerl l2 are`V` brought'intol further coalescing engagement'in` the troughs of the upper layer II.` The construotionof the icoalescing passages in the form of longrrecesses ofl inverted V-shaped cross-sectionmakes it possible to assemble the partitions easilyifrorn readily available parts, and' in the* embodiment illustrated, the apparatus has been fabricated from strip niaterial.`

The partition 9 is made in a plurality ofi sec` tions, any one of which may be taken out and removed through an opening I3 atthe top of the steam fdome, a plate YI4 being removably securedV tothe dome to aiord access to theinterior of the boiler during servicing operations. In order to support the several sections of the partition, a plurality of yangle irons I5 are secured at their en-dsto the brackets I ii and extend across the boiler,-single angle irons being provided at the ends and `sets of two irons back to back 'at the intermediate positions; Th'e sections of the par- 4tition` are rectangular andthree arerequi'red in Small bubbles, particularlythose of `say one` i fourth of an inch and smaller in diameter, tend concurrentlythe width of the boiler as shown in Fig. 2. It is not necessary that the suppressor extend longitudinally the entire length of the lre tubes and it has been shown terminating short of the smoke chest 6. Fig. 1 has been shown with a broken section so that both ends of the tubes appear; an intermediate portion of the suppressor is broken out, but it may be assumed that at least three sections are required in the length of the suppressor.

The details of construction of one of the suppressor sections are shown in Fig, 3. The lower layer I2 of troughs is formed by a plurality of metal strips I6 extending between end frame members I'I, each' strip I5 being welded at its ends to the end members. The strips I6 are arranged in planes sloping alternately in opposite directions. Adjacent top edges of the strips are spaced apart to form slits I8, and the adjacent edges which touch along the bottom of the layer may be welded together. There is thus found a series of inverted troughs presenting decreasing cross sections to bubbles rising therethrough. It has been found that particularly satisfactory peration is attained when the angle between the walls of the troughs is about sixty degrees, although other angles have been found to give satisfactory action. If desired, the troughs may be made from integrally formed angle pieces or strips previously joined along their touching edges or from wider strips bent to the required angle instead of from separate strips, the angle pieces being spaced apart to form the open inverted troughs between adjacent pieces. Thu-.s either metal strip or angle stock may be employed. The upper layer II is of essentially the same construction as the lower layer except that the strips indicated at I 9 are arranged transversely at right angles to the strips I6 of the lower layer. Th'e strips I9 are secured between longitudinal frame members or strips 20, and are secured in positions to form inverted V-shaped recesses at right angles to those formed by the strips I6.

The end frame members I'I are secured by bolts 2I to the angle irons I5 and thus hold the layer of the foam suppressing partition in position. 'I'he upper layers of the several sections between any pair of th'e angle irons I5 are secured together by bolts 22 in adjacent frame members 20 and the section of the vupper layer thusformed is secured to the angle irons I5 by clips 23 welded to the end strips I9 and secured tothe angle irons by bolts 24. The entire partition is made up by assembling the several sets of sections between the several pairs of supports formed by the angle irons I5. As shown in Fig. 3 each angle iron has its vertically extending side increased in height by the addition of a strip 25 welded along the edge of the angle iron. This construction thus provides an angle iron having one long ilange from standard angle irons and strip stock. It is to these strips 25 that the clips 23 are attached.

The foam tends to move forward from the areal above the crown sheet of the fire box, indicated at 26. In order to minimize the passage of such foam to the area below the steam dome, a vertibles moving concurrently toward the outlet from the area over the crown sheet are brought into coalescing engagement. The combination of the actions ofthe horizontal suppressor 9 and the vertical suppressor 2'I provides eiective elimination of the passage of foam to the dry pipe of the locomotive.

In order that the area over th'e crown sheet may be reached =from the area below the steam dome, the suppressor 2'I is hinged so that it may be swung downwardly out of the way, a plurality of hinges 3| being provided to secure the frame member 29 to the strip 25 of the rearmost angle iron I5. The suppressor 21 may be held in its normal upright position by any suitable device such as a spring pressed catch 32.

During the operation of locomotive boilers, the tendency to the formation of foam increases with increased concentration of substances dissolved in the water. In the construction illustrated, when the bubbles rise through the water, they pass through the slots in the lower layer of the suppressor partition and small bubbles are forced into coalescing engagement; the bubbles are again brought together on passing through the upper layer of suppressor recesses and iurther coalescing action takes place. The larger bubbles tend t0 burst upon reaching the surface and the formation of foam is minimized. It will be noted that the majority of the bubbles rising from the lower suppressor members must move laterally from their line of vert-ical ascent when the'y enter and pass upwardly through the upper layer of Suppressors. This lateral movement has been found to increase the effectiveness of the coalescing action; lateral movement obviously may be attained by different arrangements of the position of the upper suppressor recesses with respect to the lower ones; for example, the upper strips might be arranged to run parallel to the lower strips but with the outlet slots of the upper recesses staggered with respect to the slots of the lower recesses. Bubbles rising through the water above the re box tend to produce foam which may move forward toward the area below the steam dome; however, these bubbles must pass through the suppressor 21 and are thereby coalesced and the passage of the foam to the area below the steam dome is minimized. There is little or no tendency toward the formation of foam at the forward end of the boiler, and it will thus be apparent that the Suppressors 9 and 21 in combination electively prevent the passage of foam to the steam dome and thence through the dry pipe to the cylinders of the locomotive.

While the invention has been described with particular reference to its use in a locomotive boiler, other applications will readily be apparent to those skilled in the art. Various modiiications may be made within the spirit and scope of the invention and it is intended by the appended claims to cover all such modiiications.

What I claim and desire to secure by Letters Patent is:

1. In apparatus for retarding foam and Viroth formation in boilers and pressure Vessels inclusive of a container for a body of liquid sul ject to evaporating influences and having foam producing bubbles rising therethrough, the improvement which comprises means within the body of liquid under treatment vin the boiler providing a plurality of elongated horizontal recesses of upwardly decreasing width providing narrow slits along the tcp thereof for the escape of fluid moving upwardly therethrough whereby bubbles rising concurrently through said body of liquid enter said recesses and are brought into coalescing engagement as they approach said slits. Y

2. In apparatus for retarding foam and froth formation in boilers and pressure vessels inw elusive of a container for a body ci. liquid sub ject to evaporating influences and having foam producing bubbles rising therethrough, the improvement which comprises means located withinA the body of liquid under treatment in the boiler providing a plurality of elongated horizontal recesses of upwardly decreasing width proM viding narrow slits along the top thereof for the escape of lluid moving upwardly therethrough wherebyV bubbles rising concurrently through said body of liquid enter said recesses and are brought into coalescing engagement as they ap proach said slits, and a second similar means also within the body of liquid providing a plu`H rality `of similar horizontal recesses above said rst mentioned means for further facilitating the coalescing of the bubbles rising from said first mentioned means.

3. In apparatus for retarding foam and froth formation in boilers and pressure vessels inelusive of a container for a body of liquid subject to evaporating iniluencesand having foam producing bubbles rising therethrough, the improvement which comprises a partitioning member supported in the liquid body in a substantially horizontal position, said partitioning member including a plurality of flat strips of metal arranged with their edges substantially parallel andrwith adjacent strips in oppositely inclined planes to provide a plurality of inverted troughs of V-shaped cross section, adjacent top edges of said strips being spaced a small distance to provide slits along the peaks of said troughs whereby bubbles rising concurrently through said body of liquid entersaid troughs and are brought into coalescing engagement as' they approach said slits.

4. In apparatus for retarding foam and froth formation in boilers and pressure vessels inclusive of a container for a body of liquid subject to evaporating innuences and having foam producing bubbles rising therethrough, the improvement which comprises a pair of partitioning members supported in the liquid body in substantially horizontal positions, one of said members being supported above the other, each of said partition members including a plurality of flat strips of metal arranged with their edges substantially parallel and with adjacent strips in oppositely inclined plan-es to provide a plurality of inverted troughs of V-shaped cross section, adjacent top edges of said strips being spaced a small distance to provide slits along the peaks of said troughs whereby bubbles rising concurrently through said body of liquid enter said troughs and are brought into coalescing engagement as they approach said slits, the strips of said one member being so positioned with respect to those of the other member below it that the majority of the bubbles rising from the slits in said other member must move laterally to reach the slits in said one member.

5. In apparatus for retarding foam and froth formation in boilers and pressure vessels inclusive of a container for a body of liquid subject to evaporating influences and having foam producing bubbles rising therethrough, the improvement which comprises a pair of partitioning members supported in the liquid body in substantially horizontal positions, one of said members being supported above the other, each of -said partition members including a plurality of hat strips of metal arranged with their edges substantially parallel and with adjacent strips in oppositely inclined planes to provide a plurality of inverted troughs of il-shaped cross section, adjacent top edges of said strips being spaced a small distance to provide slits alongthe peaks of said troughs whereby bubbles rising concurrently through said body of liquid enter said troughs and are brought into coalescing engagement as they approach said slits, the strips of said one member being` positioned with their longitudinal axes transverse to those of the strips of the other member.

6. In apparatus for retarding foam and froth formation in boilers and pressure vessels inclusive of a container for a body of liquid subject to evaporating influences and having foam producing bubbles rising therethrough, the improvement which comprises a pair of partitioning members supported in the liquid body in substantially horizontal positions, one of said members being supported closely above the other, each of said partition members including a plurality of flat strips of metal arranged with their edges 'substantially parallel and with adjacent strips in oppositely inclined planes intersecting at angles of approximately sixty degrees to provide a plurality of inverted troughs of V-shaped cross section, adjacent top edges of said strips being spaced a small distance to provide slits along the peaks of said troughs whereby bubbles rising concurrently through said body of liquid enter said troughs and are brought into lcoalescing engagement as they approach said slits, the strips of said one member being positioned transversely of the strips of the other member.

7. In apparatus for retarding foam and froth formation in boilers and pressure vessels inclusive of an elongated container for a body of liquid subject to evaporating influences and. having -foam producing bubbles rising therethrough and outlet means near the top of the container and intermediate the ends thereof for the discharge of vapor, the improvement which comprises a substantially horizontal partition member composed of inverted substantially V-shaped troughs supported in the liquid body below the outlet means and having openings therein arranged for inducing a coalescing engagement of bubbles rising through the liquid, and a vertically extending transverse partition member supported in the container adjacent said horizontal member and between one end of the container and the outlet y means and having openings therein for inducing coalescing engagement of bubbles moving therethrough toward the outlet.

8. In apparatus for retarding foam and froth formation in boilers and pressure vessels inclusive of an elongated container for a body of liquid subject to 'evaporating influences and having foam producing bubbles rising therethrough and outlet means near the top of the container and intermediate the ends thereof for the discharge of vapor, the improvement which comprises a substantially horizontal partition member composed Vof inverted substantially V-shaped troughs supported in the liquid body below the outlet means and having top openings therein arranged for inducing a coalescing engagment of bubbles rising through the liquid, and a vertically extending' transverse partition member supported in the container adjacent said horizontal member and between one end of the container and the outlet means for inducing coalescing engagement of bubbles moving therethrough toward the outlet, said vertical member comprising a plurality of parallel strips supported alternately in oppositely inclined planes to form V-shaped troughs opening laterally toward said end of the container and being spaced to form slits along the side adjacent said outlet means, said vertical member being hinged for swinging movement to afford access to said end of the container from above said horizontal member.

9. In apparatus for retarding foam and froth formation in boilers and pressure vessels inclusive ofV an elongated container for a body of liquid subject to evaporating influences and having foam producing bubbles rising therethrough and outlet means near the top of the container and intermediate the ends thereof for the discharge of vapor, the improvement which comprises a substantially horizontal partition member composed of inverted substantially V-shaped troughs supported in the liquid body below the outlet means and having openings therein arranged for inducing a coalescing engagement of bubbles rising through the liquid, and a vertically extending transverse partition member supported in the container adjacent said horizontal member and between one end of the container and the outlet means for inducing coalescing engagement of bubbles moving therethrough toward the outlet, each of said members comprising a plurality of parallel strips secured in juxtaposition and in alternate oppositely inclined planes to provide a plurality of troughs and spaced apart along their 8 I sides toward thel outlet to provide passages of decreasing cross section having narrow slots for the escape of liquid and bubbles moving toward said outlet.

10. In apparatus for retarding foam and froth formation in boilers and pressure vessels inclusive of an elongated container for a body of liquid subject to evaporating influences and having foam producing bubbles rising therethrough and outlet means near the top of the container and intermediate the ends thereof for the discharge of vapor, the improvement which comprises a substantially horizontal partition member composed of inverted substantially V-shaped troughs supported in the liquid body below the outlet means and having top openings therein arranged for inducing a coalescing engagement of bubbles rising through the liquid, and a vertically extending transverse partition member supported in the container adjacent said horizontal member and between one end of the container and the outlet means and having openings therein for inducing coalescing engagement of bubbles moving therethrough toward the outlet, said vertical member being mounted for movement away from the vertical to afford access to said end of the container from above said horizontal member.

, WALTER B. LEAF.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS i Date

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