US2357423A - Steam separator - Google Patents

Description

5, P. B. STEAM SEPARATOR Filed Aug. 19, ;941

2 Sheets-Sheet 1 INVENTOR.

Sept. 5, 1944.

P. B. PLACE STEAM SEPARATOR med Aig. 19, 1941 2 Sheets-Sheet 2 a %Nga ATTORNEY.

Patented Sept. 5, 1944 STEAM SEPARATOR Palmer B. Place, Tenafly,

bustion Engineering Company, N. Y., a corporation of Delaware N. J;, assignor to Com- Inc., New York,

Application August 19, 1941, Serial No. 407387 6 Claims. (c. 122-491) i This invention relates to the art of steam separation in steam boilers.

In the operation of steam boilers the concentration in the boiler water, of dissolved salts, Suspended matter, and the like, steadily increases, and as the concentration thereof 'increases so does the tendency toward foaming in' the steam and water drum or drums in which the steam is separated, and in which the concentration is higher than in other portions of the boiler. In consequence, the Carry-over" in the separated steam of Water with dissolved solid matter and impurities, increases with detrimental results. Thus it becomes necessary to "blow down the boiler which involves losses due to the discarding of the boiler water and the chemicals added thereto for treatment.

I am aware that it has heretofore beeen pro-` .posed to provide separators for the steam and water drums of boilers, to separate out the water entrained with the steam, and such devices are' effective to a certain degree. These operat by change in direction of steam flow (see, for example, the United States patent to Kerr, No.` 1',901,912, of March 21, 1933). i

It is the primary object of the present invention to make it possible to allow the concentration to increase to a point far above that at present permissible, as will further appear.

How the foregoing, together with such other objects and advantages as may hereinafter appear or are incident to my invention, are realized, is illustrated in the accompanying drawings, Wherein Figure, 1 is a cross-section through a steam and water drum more or less diagrammatically illustrating the invention, and

Figure 2 is a fragmentary section taken on A the line 2-2 of Figure 1.

Figure 3 is a cross section similar to Figure 1 but illustrating a modification of the invention, and i Figure 4 is a 'cross section through a drum il- I lustrating still another modification, in this instance in somewhat greater detail.

In the arrangement of Figure 1 a plurality of rows'of tubes 1 deliver a mixture of steam and water into the steam drum A. In this instance, there are four rows of such tubes, which is a customary arrangement. These tubes deliver a relatively high velocity mixture, such as the mixture from an upright water wall section or sections of a boiler furnace or other tubes of the boiler subject to radiant heat. In this instance, the three uppermost rows of tubes 'I' deliver steam and water mixture into the 'space above the normal water level 8 of the drum, the

lowermost row delivering below the normal water level.

Downcomer tubes 9 return water from the steam drum to other portions of the boiler. For

v purposes of illustration but one row of such downcomer tubes is shown; It is to be understood that thenumber of rows of such tubes will vary with -the particular installation, as is well understood in the art.

In addition to the inlet tubes 1, it is also to be understood that the boiler may have other inlet tubes (not shown), :connected into'the drum for delivering relatively low velocity steam and water mixture from' portions of the boiler subject to convection heat. These likewise deliver into the drum below the normal water level. The number of such tubes will also vary with the particular installation.

` In an upper rpart of the drum there is provided steam outlet means, in this instance a single row of tubes Io; Here, again, it is to be underto be hereinafter more particularly referred to.

Above the baffle I is a second partition member or bai'fie 2 which extends 'downwardly from the drum wall from a point adjacent the row of tubes i0- and on that side of such row which is toward the rows of tubes 1. This baffie 2 like- Wise extends longitudinally of the drum and inclinese rearwardly and downwardly. It is spaced from the portion la of the bame l and terminates Well above the horizontal portion of the baffie l. Substantially semi-circular upright end plates l2 extend downwardly from the top portion of the drum wall to a point below the normal water level of the drum, as shown in Fig. ure 2.

The main baflie l cooperates with the end' plates so as to partition the space above the water into two general spaces, i. e., a space B below the baffle which constitutes aseparation space of substantial size, and a space C above the bame, Communication between the' space' Band the space C above the bame l is afforde'd by. the

opening or passage ll hereinbefore referred to. That portion of the separation space B defined by the upwardly inclined portion la of the baffie, the end plates, and the Water, may be termed a throat B", which constricts in a direction away from the tubes.

It will be seen that the three uppermost rows of tubes l discharge directly into this throat. These tubes have the usual spacing for ligament strength. It will be seen that the individual jets or streams of steam and water mixture delivered by such tubes, spread, fan out or bush so that they merge into one another at a point somewhat in advance of the dot and dash line 13, and also that the jets or streams delivered by the uppermost row of such tubes 1 impinge on the portion la of the baiTle at a point in advance of the line !3. such portion l a is of such length and is so located with reference to the drum wall and the tubes 'I as to cause such impngement to occur at a point intermediate the ends of the portion I a and well removed from each end. The inclination of the portion la is such that the impingement occurs at a small angle.

In consequence, at approximately the plane of line l3, the individual jets or streams merge to form and to maintain a moving but continuous sheet or screen or barrage of steam and water, i. e., a barrage which is continuous across the throat-from portion !a to the water level and from one end plate or baffle |2 to the other end plate or baflie. The screen or barrage is also of considerable depth as it only dissipates after entrance into space B, proper. i

In the region of the line or plane !3 and from thence on, the steam, being lighter, tends to slow up somewhat, but the water in the mixture, being heavier, tends to proceed in its initial downward direction at substantially its initial velocity, until it joins the water in the drum.

Due to the foregoing, a number of things occur. In the first place, there is a separation of water from the steam and water mixture de-' livered into the throat, because, as just above described, water in such mixture continues on to join with the water in the drum, and the steam in such mixture enters the space B proper. In the next place, it will be seen that the screen or barrage moves in a direction directly counter to the flow of steam leaving the space B on its way to the opening I l. Thus any water in the steam so leaving the space B proper receives the impact of the barrage. Thus the water in such steam is beaten out by the barrage, and primarily by the water therein, dispersed there throughout. Thus, further separation of water from steam occurs. In the third place, the foam and foam producing substances in the jets or streams of steam and water mixture delivered bythe tubes, are carried, along with the steam and water of the mixture, into the space B proper. Any foam attempting to leave such space proper, receives the impact of the moving barrage and is broken up. Similarly with spray.

Since the barrage is substantially continuous across the throat, all steam leaving the space B proper must' pass through the barrage in leaving such space, on its way to the opening ll. Thus, because of the double separating effect above de scribed, the steam leavingthro-ugh opening ll is almost freed of water. B the same token, no foam is carried along with such steam. Whatever small amount of water remains in the steam entering the space above the main baffle` is removed by reason of the second baflle 2,` which causes two changes in the direction of flow of the steam on its way from the opening I I to the outlet means, as indicated by the arrow. This ordinan'ly suffices to separate the remaining water. In some installations, however, it may be desirable to add additional separating means such as diagram matically indicated at |5, this being a conventional plate type of Separator or drier. In all cases the main separation occurs in advance of the opening I l, as described.

In order to drain water collecting above the main baie, I have provided a plurality of drain pipes !4, which discharge at a point below the normal water level of the drum.

By the foregoing I have found by actual experience that I am enabled to allow the concentration of solids to build up far beyond what has heretofore been practical before it is necessary .to blow down. In some installations, I have found that the concentration could be safely increased to eight times over what has heretofore been customary practice, before it became necessary to blow down.

It will be seen that the arrangement is quite fiexible in that it takes care of a substantial variation in the level of water in the drum. To illustrate, as the water level sinks below the point at the line indicated, the jet from the lowermost row of tubes 1 spreads out, ensuring the maintenance of the continuous screen or barrage heretofore described. The point of complete merging may shift, but the length of the throat is such as to ensure such merger.

While the bafiles are shown as composed of single pieces, they may be sectionalized if required, and they may be supported in any desired manner, so long as excessive leakage is avoided. In this connection, it is to be observed that the opening l I should be the sole communication between spaces B and C, in the sense that there should be no other communication such as would defeat the proper functioning of the device.

-In the arrangement thus far described the movement of the screen or barrage is directly,

counter-flow to the. movement of steam from the separation space and also directly counter to the flow of any foam trying to escape from said space.

In the form shown in Figure 3, the screen or I barrage moves more directly across the opening or passage afiording communication between the separation space B and the space above. More specically, the main bafile l' in this instance rises upwardly from a point below the normal water level and adjacent to the wall of the drum opposite the inlet tubes, and then inclines rearwardly and upwardly, to a point short of the second longitudinally extending baffie 2', so as to provide an opening or passage ll' which affords the communication between separation space B and the space C.

A third longitudinally extending baffie 3 eX- tends inwardly from the wall of the drum a short distance and cooperates with baffie 2' to provide a slot IE, extending longitudinally of the drum, through which the steam and water mixture delivered by one or more of the rows of. tubes 'I is delivered in the form of a continuous sheet, screen or barrage IT which impinges on the baflle I' at a small angle ashereinbefore described. This sheet lies between space B and the opening or passage' ll', flowing across the latter.

The operation is essentially as before de- I scrbed. In order for steam 'to leave the sepa-` ration space B, 'it must pass through the sheet or barrage I'I and receives theimpact thereof." As before, water carried in such steam is beaten out. Likewise any foam tending to leave the separation space B, receives the impact of said sheet or screen or barrage and is broken up. For most installations, the relatively small amount of water` remaining in the steam as it passes through opening I I' is removed by the action of the baflie 4 which causes the steam to take a continuous path to the outlet tubes ll), with change in the direction of flow. In other installations a final Separator or drier such as indica'ted in Fig. 1 may be employed. Water separatng out above the baflie l' finds its way to the water in the drum at !8. Desirably the lower portion I" of the baffie l' inclines rearwardly and downwardly as shown, in order to cause the water separated out in separation chamber space B to take the course indicated generally by the arrow.

This arrangement likewise ensures the efiective separation of water and concentrates and pre- Vents carry over of foam.

In the arrangement shown in Figure 4, the main baffie I is substantially upright and the upper end thereof terminates short of and 'is spaced away from the second bame 2", again providing an opening H" which constitutes the communication between the separation space B and the space C.

As before, the third longitudinally extending baffie 3' is so disposed with reference to the baflie 2" as to discharge the mixture delivered by one or more rows of tubes 'i in the form of a downwardly directed sheet,screen or barrage l'',wh-ich likewise impinges upon the main baffle at a small angle Itwill beseen that in this arrangement, like that of Figure 3, a continuous sheet, screen or barrage moves across the opening affording communication between spaces B and C, through which all steam leaving space B must pass and with which any foam attempting to leave such space must contact and thus be broken up.

Reverting to` Figure 1, the portion lb of the main bame I is turned upwardly for the reason that in some installations there may be, in addition to the tubes 'I' shown, other tubes at the opposite side of the drum, discharging steam and water mixture above the normal water level in the drum. By inclining the portion lb as shown, the arrangement may be accommodated to such an installation. In this connection the number of tubes so delivering the steam and water mixture into the throat formed by the portion lb should not be great enough to counteractthe effect of the barrage in throat la.

This application is a continuation in part of my application Serial No. 390379, filed Apr-11 29, 1941.

I claim:

1. In a steam and water drum having inlet tubes at least some of which delver a mixture of steam and water into the drum above the normal water level thereof and having steam outlet means, the combination of a main 'baffle and second bale spaced from the main baffle, both baffles extending longitudinally of the drum, and end bafiies, all of said baffies cooperating to divide the free regionof the drum into two spaces, namely, a separating space for entering steam and water mixture and a space from which steam is discharged via the said outlet means, the only communication between the separating space and the second space being by way of the opening provided bi' the spacing apart of the said main baffie and said second baie, and a third longitudinally extending bafiie spaced from `but cooperating with said second baflie to direct some of the mixture of* steam and water entering the drum in the form of a continuous sheet moving across said opening and between it and said separati'ng space and impinging on said main baffle, whereby all steam leaving said *separating space must pass through said sheet on its way into thesecond space and foam in attempting to leave said sep-' arating space meets with and receives the impact of said sheet.

2. In a steam and water drum having inlet tubes at least 'some of which deliver a mixture' of steam and water into the 'drum above the normal water level thereof and having steam outlet means, 'the combination of a main baffie and second bafiie spaced from the main baffle, both baffles extending longitudinally of the drum, and end baflies, all of said baflies cooperating to divide the free region of the drum into two spaces, namely, a separating space for entering steam and water mixture and a space from which steam is discharged via the said outlet means,' the only communication between the separating space and the second space being by way of the opening' provided by the spacing apart of the said main bafiie and said second baifie, and a third longitudinally extending bame spaced from but cooperating with said second baflie to directsome of i the mixture of steam and water entering the drum in the form of a continuous sheet moving' across said opening and between it and said separating space and impinging on said main bafiie, whereby all steam leaving said separating space must pass through said sheet on its way into the second space and foam in attempting to leave said separating space meetswith and receives the impact *of said sheet, said main bame rising from the region of the normal water level and inclining from the Vertical, the inclination with reference to the line of movement of said sheet being such that the sheet impinges on said main baffie at a small angle and is defiected downwardly.

3. In a steam and water drum having inl'et tubes at least some of which deliver a mixture of steam and water into the drum above the normal Water level thereof and having steam outlet 'means, the combination of a main bame and second baffle spaced from the main bafiie, both baffies' extending longitudinally of the drum, and end bafiies, all of said baflies cooperating to divide the free region of the drum into two spaces, namely, a separating space for entering steam and water mixture and a space from which steam is discharged via the said outlet means, the only communication between the separating space and the second space being by way of the opening provided by the spacing apart of the said main baffie and said second baflie, and a third longitudinally extending bafiie spaced from but cooperating with said second baflie to direct some of the mixture of steam and water entering the drum in the form of a continuous sheet moving across said opening and between it and said separating space and impinging on said main baffie, whereby all steam leaving said separating space must pass through said sheet on its way into the second space and foam in attempting to leave said separating space meets with and receives the impact of said sheet, said main baffle being substantially vertically disposed and the second and third longitudinally extending bafiies being so disposed that the said sheet mpinges upon said main baffle at a small angle and is deflecteddownwardly.

4. In a steam and water drum having steam outlet means, bame means dividing the free region of the drum into two longitudinally extending spaces, one being a separating space for entering steam and water mixture and the other a'space from which steam is discharged Via said outlet means, said baffie means having one longitudinally extending edge terminating short of the drum wall to provide for an opening constituting the only communication between the said two spaces, and means for delivering steam and Water mixture into said separating space across said opening and immediately in advance thereof and so disposed With reference to the baffle means as to cooperate therewith to form the said so delivered i steam and water mixture while on its incoming course, into a continuous, longitudinally extending barrage interposed in advance of said opening and screening it from the steam separating space and extending across the path of all steam leaving the separating space on its way into the second space to the outlet means, whereby all steam leaving the separating space must first pass through said barrage, and foam attempting to leave said separating space meets with and receives the impact of said barrage.

5. In a steam and water drum having steam outlet means, bafile means dividing the free region of the drum into two longitudinally extending spaces, one a separating space for incoming steam and water mixture and the other a space from which steam is discharged via said outlet means, said bafl'le means having one longitudinal edge portion terminating short of the drum wall to provide for an opening constituting the only communication between said two spaces, said edge portion cooperating with the water in the drum to constitute a'throat for the steam separating space, and inlet tubes delivering steam and water mixture into said throat, the said tubes 'being disposed with reference to each other, to the water in the drum and to said longitudinal edge portion of the baflle so that steam and water mixture on its incoming course is formed into a continuous longitudinally extending barrage in the threat in advance of and adjacent to said opening and screening it from the steam separating space, said barrage moving counter to steam leaving said steam separating space on its way to said opening and toward the outlet means, whereby all steam leaving said separating space on its way to the outlet means must first pass through said barrage and foam attempting to leave said separating space meets with and receives the im pact of said barrage.

6. The method of separating steam and water in a steam and water drum having a steam separating space for entering steam and water mixture and an outlet passage for steam, which comprises continuously delivering steam and water mixture into the separating space of the drum and continuously forming it on its inward course into a continuous barrage immediately in advance of said passage, which barrage extends longitudinally of the drum, screens the said passage from the steam separating space of the drum, and moves in a direction with respect'to said passage such that steam and water of the barrage 'cannot pass directly to said passage, whereby all steam ,leaving the separating space via said outlet passage must first pass through said barrage and alli foam in attempting to leave said separating space meets with and receives the impact of said barrage.

PALMER B. PLACE.

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