US2378429A - Steam separator - Google Patents

Description

P. B. PLACE STEAM SEPARATOR June 19, 1945.

Filed April 29, 1941 m m E V m.

' PALMER B-PLAcs Patented June 19, 1945 UNITED STATES iPATENT OFFICE STEAM SEPARATOR Palmer B. Pate, 're'nafly, N. J., assignor to Coinbustion EngineeringCompany,.1nc,, New York, N. Y., a corporation of Delaware Application April 29, 1941, Serial No. 390,879

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 beenproposed to provide separators for the steam and It is theprimary object of the present invention to: make it possible-to allow the concentration to increase to a point far above that at presentpermissible, as will further appear.

- How th 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 drawing,

whereina v Figure 1 is a cross section through a boiler drum illustrating in diagrammatic form one arrangement for carrying out my invention.

Figure 2 is a similar view illustrating a modification of the invention.

' The species shown in the above figures is covered broadly .in my copending application Serial No. 407,387, filed August 19, 1941, now

Patent No. 2,357,423, issued September 5, 1944,v

which case, however, contains no claim specifically directed to this species. Reference may also be had to my copending application Serial No. 522,160, filed February 12,1944, in which.

a different species is claimed.

According to Figure l, a plurality of rows of tubes 1 discharge a mixtur of steam and water into the steam and water drum A above the normal water level 8 thereof. This is a customaryarrangement, and, in this instance, four such rows of tubes are shown. These tubes usually deliver a relatively high velocity mixmm, such as the mixture from an upright water wall section or sections of a boiler furnace or other portions of the boiler subject to radiant heat. Such water walls being subjected to radiant heat, generate steam in large volume. In' consequence, the delivery therefrom to the steam drum occurs at relatively high velocity. An additional row of tubes 1 discharges into the drum below the normal water level. be a number of additional rows. Downcomer tubes ID are also connected into the wall of the drum as is customary, and while I have shown but one row of such tubes there may be other rows. At the topof the drum a steam outlet is provided, in this instance a row of tubes ll.

. Extending inwardly from the drum wall, at aIpoint intermediate the middle rowsof tubes 1, is a plate, I. This plateextends into the drum space in a direction generally parallel the axes ofv the row of tubes to either side thereof. A second plate 2 extends inwardly from the drum wall at a point between the steam outlet tubes 1 l and the row of tubes 1 adjacent thereto. This plate extends in a direction generally at right angles to plate I and terminates short thereof so as'to provide a discharge slot I2 for th mixture delivered to the space defined by plates I and 2.

It will be seen. that the inner edge portion of plate-l extends somewhat beyond the slot l2.

Theplates I and 2 act as a distributing manie fold,'distributing the steam and water longitudinally. Thus the steam-water mixture delivered to the space defined by plates I and'Z is dischargedqfrom the slot in the form of a downwardly inclined sheet. This sheet extends longitudinally of the drum. Due to the mixing action taking placewithin the space defined by the plates,'any gobs'of Water delivered by: the tubes are broken up and the water is dispersed through the steam. The size of the slot should besuch as to secure discharge of the steam and water; mixture as a sheet. It may conveniently have an area approximately that of the tubes discharging into'the space defined by the plates.

The number of tubes discharging into suchspace closely adjacent to the normal water level of the drum, plate 3' inclines rearwardly andupwardly with respect to the sheet and toward plates I There may and 2thus providing, along with the water in the drum, 9, constricting or contracting space B into which the sheet of steam and water discharged from the slot I2 and indicated by the arrow I3, is delivered. The inclination of plate 3 with respect to the line of discharge of the sheet from the slot is such as to confine and direct the sheet at a sharply acute angle against plate 3 and into the apex portion of space B. Thus th sheet drives and crowds into a con stricting space and at an angle toward the water in the drum.

The upper edge of plate 3 terminates short of plate 2 and lies in a plane above the slot 12, thus providing an opening or space 14 between plates 2 and 3 for the escape of steam. By this arrangement the sheet of steam and water issuing from the slot and striking against plate 3 is interposed between the opening 14 and the steam and water mixture which is delivered into the drum by those tubes 1 which are located below plate -I and any steam and water mixture leaving the water in the drum.

Extending inwardly and downwardly from the drum wall at a point intermediate the steam outlet tubes II and theadjacentrow of tubes 1 is a fourth plate marked 4. This plate is likewise inclined, in the same general direction as plate 3, and lies above the latter plate and is spaced therefrom. Thus the steam leaving .the constricting space B through opening 14 bends and enters the passage 15, makes .a further bend around the lower edge of plate '4 as indicated by the arrow, and eventually passes to the outlet tubes ll.

The operation is as follows: The sheet of steam and water mixture delivered through the slot I2 impinges upon the plate .3 at a slight angle and drives .on in the same general direction and crowds into the apex portion of the space B. Thus it will be seen that substantially all the steam which escapes through opening 14 must pass through the sheet and receive the impact thereof. Because the sheet impacts on plate 3 at a very acute angle, practically all of the steam of the steam .and water mixture comprising the sheet must also pass through the sheet on its way to the opening l4. There may be a small quantity of steam passing upwardly along the lower face of plate 3 due to eddying, but should there be any, the amount thereof is relatively trifling.

Inasmuch as the steam of the sheet is lighter, it tends to decrease in velocity; but the water in the sheet being heavier, continues substantially at initial velocity. Because of this, the amount of water to steam in the sheet increases as the apex portion of the space is approached, where the sheet is largely water.

Any foam carried into the drum through the tubes 1 and 9 and which may collect within the space B is broken up by the impact of the steam and water issuing from the opening 12. I attribute this largelyto the water in the sheet. In any event, I have observed that any team tending to rise with the steam flow is effectively prevented from leaving the space 13 by the sheet issuing from opening 12. Since the steam rising toward the opening 14 travels at lower velocity than does the sheet, a separating action occurs due to the impact of the sheet, and water and .impurities in the rising steam are, as it were, beaten out and are driven towardthe apex end of the space, along with the water in the sheet travelling to said end.

Thus, practically all of the steam and water mixture which enters the steam space is driven into the constricting space and practically all of the steam leaving the space must first pass through the sheet. There may be some steam or steam and water mixture rising from the water in the small space between the lower end of plate 3 and the drum wall, but should there be any, the amount thereof would be relatively trifling.

The quantity of water carried toward the apex end of the space, causes a downward current which circulates through the body of water within the drum in the general course indicated by the arrow l6. Preferably I provide a bafiie 3a extending from the bottom of plate 3 in the direction shown, which deflects the downward current and assures its flow along the course shown. The object of such deflection of the current is to avoid its sweeping over the downtake tubes If] so as to preclude any entrained steam bubbles being sucked into the downtake tubes.

In consequence of the foregoing, the steam leaving through the opening I4 .ca-rries but relatively little water. Most of the water is removed in space B and whatever water remains is removed by the second separation .caused by plate 4 which causes the steam .to change its direction of flow as before described, and throw out the remaining water.

.I am not certain whether the described explanation of operation is correct in its entirety. I do know that the vfoam is destroyed and that water drives into the apex end of spaceiB, and -believe these to be very important factors. .However that may be, I have found by actual experience that I am able to allow the concentration of solids to build up far beyond what has heretofore been practical, before it is necessary :to blow down. To illustrate, .I have, in a modem boiler installation, substituted my separating means for the usual separating :means which opcrates .on the principle of change in direction of steam flow, and found that the concentration .in that installation was increased eight times over what had there been customary before it became necessary to blow down, thus effecting very substantial operating savings. Irrespective, of whether that is an unusual instance, I have uniformly found it possible to very materially increase concentration before blow down becomes necessary.

Since the lowermost row of tubes 1 discharges below the normal water levelB and the next adjacent row will also discharge into water, particularly if the water level rises as it may do, to a point approximately as high as indicated at 11, there will be turbulence. To minimize this turbulence of water to maintain the general character of operation hereinbefore described, I provide a shielding plate [8 which extends inwardly from the drum wall at a point below the lowermost row of tubes '1 and then upwardly to a point approximating the line of high water.

Referring now to Fig. 2, in some instances the two uppermost rows of tubes 1 may not be present, in which case plate .2 may be omitted, plate I raised and the upper lip of plate 18 extended to form a discharge opening l2 between plates I and 18.- In this modification, the three lowermost tubes 1 supply all of the stem and water mixture through opening l 2 for the sheet which serves as the screen to prevent water spray or foam from pass-ing through the screen ofitake opening I4 and through which screen practically all of the steam must pass in its escape to opening l4.

It is to be understood that the customary end .plates are provided in the constructions of Figures 1 and 2. v

The herein described method of and apparatus forseparating steam in the steam and water v into the steam space of the drum and some to deliever below the normal water level, said drum also having steam outlet means in an upper part thereof, means for separatin steam and water comprising a longitudinally extending first baf fle extending inwardly from the drum wall at a point adjacent totubes delivering steam andwater mixture into the steam space, a longitudinally extending second bafile also extending inwardly from the drum wallat a pointadjacent to tubes delivering steam and water mixture into the steam space but terminating short of the first bafile to provide a longitudinally extending slot whereby steam and water mixture delivered into through said slot in the form of a continuous longitudinally extending sheet or barrage, a longitudinally extending third baffle rising upwardly space above the water in the drum without substantial agitation of the water in the drum.

2. In a steam and water drum having a plurality of rows of tubes for delivering steam and water mixture thereinto, some disposed to deliver into the steam space of the drum and some to drum in which the steam separates from the deliver below the normal water level, said drum also having steam outlet means in an upper part thereof, means for separating steam and water comprising a longitudinally extending first baffle' extending inwardly from the drum wall at a point adjacent to tubes delivering steam and water mixture into the steam space, a longitudinally extending second baffle also extending inwardly from the drum wall at a point adjacent to tubes delivering steam and water mixture into the steam space but terminating short of the first the space defined by said tubes is discharged I fies, said discharge opening being above said slot,

leavingthe space below the first and third baffies must pass on its way to said discharge opening and to the outlet means and foam attempting to leave said space below the first and third baflles meets with the impact of said barrage, and I t a fourth baflle extending inwardly from the drum wall at a point adjacent to but below tubes discharging steam and water mixture into the drum below the water level and extending upwardly to a point substantially above the normal water level so as to cause steam and water mixture delivered below the water level to pass upwardly into the.

baffle to provide a longitudinally extending slot 7 whereby steam and water mixture delivered into the spacedefined by said tubes is discharged through said slot in the form of a continuous longitudinally extending sheet or barrage, a longitudinally extending third bafile rising upwardly and rearwardly from the normal water level and extending toward said second baille but terminating short therefrom to provide a discharge opening from'the space below the first and third baffies, said discharge opening being above said slot,

said third'baflle being so disposed with reference to the first and second baflles that the sheet discharged through the discharge slot impinges upon said third baiile at a small angle, whereby said sheet is disposed in advance .of the discharge opening and constitutes a barragethrough which all steam leaving the space below the first and third baflles must pass on its way to said discharge opening and to the outlet means and foam attempting to leave said space below the first and third baflles meets with the impact of said barrage, a fourth baflle extending inwardly from the drum wall at a point adjacent to but below tubes discharging steam and water mixture into the drum below the water level and extending upwardly to a point substantially above the normal water level so as to cause steam and water mixture delivered below the water level to pass upwardly into the space above the water in the drum without substantial agitation of the water in the drum, and a fifth baffle extendin inwardly and downwardly from the drum wall at a point adjacent said second balile and extending some distance past the upper edge of the third baffle and being spaced away from the third baflle whereby steam leaving said discharge opening is caused to change direction of flow onits way to said outlet means.

PALMER B. PLACE.

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