US2188266A - Boiler section - Google Patents

Description

L. N. HUNTER Jan. 23, 1940.

BOILER SECTION Filed Feb. 10, 1937 2 Sheets-Sheet 1 Louis ]V.Hunfer 6,4

Jan. 23, 1940. HUNTER 2,188,266

BOILER I SECTION Filed Feb. 10, 1957 2 Sheets-Sheet 2 INVENTOR Patented Jan. 23, 194 0.

BOILER SECTION Louis N. Hunter, J ohnstown, Pa., assignor to The National Radiator Company, a corporation of Maryland Application February 10, 1937, Serial No. 125,045

' 1 Claim. (01. 122-5225) This invention relates to boiler sections, and particularly to a boiler section provided with internal means for reducing the moisturecontent of the steam generated in the boiler section. The

'invention is primarily applicable to sectional boilers as distinguished from boilers of single or one-piece construction.

It is generally recognized that in the generation of steam in a boiler a certain amount of water in the form of small drops or particles is carried along with the steam. It is also generally recognizedthat the presence of such water particles or drops in the steam is not desirable. Steam which is relatively free from such susi pended particles is frequently referred to as dry steam,whereas steam which contains a considerable amount of such water is referred to as moist or wet steam.

The plane of separation between the water space in a boiler and the steam space is quite generally termed the water line and is also known as the steam releasing area or steam releasing surface. When steam leaves the. water surface or the water line, it has a tendency to carry with it the small particles or droplets of water above referred to. One factor which determines the amount of water carried off is the rate of firing of the boiler. The higher the firing rate the greater the rate at which steam is generated and there is, therefore, a greater} velocity of the steam leaving the surface of the water, tending to entrain a greater amount of water. Another factor which determines the amount of moisture in the steam is the relation of the steam releasing area in proportion to the capacity of the boiler. If the steam-releasing area of the boiler is relatively small as compared with the amount of steam being generated, the steam will leave the water line at a greater velocity because of its concentration over a small area and, therefore entrain more water. e

A third factor affecting the carrying off of small particles of water is the circulation of the water in the boiler below the water line. As the,

steam is generated, convective currents, of course, are set up in the water, resulting in the presence of upwardly moving currents of water and downwardly moving currents. The upwardly moving currents are the hotter ones and steam is released more rapidly over these areas of upwardly moving currents than at other points on the surface of the Water. This results in the tendency for the steam generated at these points to carry a greater moisture content and this is aggravated by the currents of water itself. The heating engineer should bequalified to determine the proper size of boiler so that it does not have to be fired at an excessive rate, and the boiler designer endeavors to provide an adequate steam-generating surface for the amount ofv steamrequired.

The third factor, however, i. e., the movement of the currents of water within the boiler itself, is inherent to the operation of the boiler and the elimination of wet steam from this source .has heretofore presented a problem. This is particularly true in the case of sectional boilers used in heating plants where the requirements on the boiler fluctuate Widely with variations in the outside temperature and where, for economical purposes, the boilersections should be designed for use either in hot water, steam or vapor heating systems.

According to the present invention, it is proposed to provide bafiles which are generally inclined with respect to the water line located across the areas of greatest upward movement of the water, i. e'., the areas where steam is generated at the highest rate,.so arranged that all of the steam generated this area is deflected in a generally horizontal direction and then caused to reverse its flow at a sharp angle one or more times before reaching the steam take-01f of the boiler. By deflecting the direction of flow of the steam sharply, the entrained particles of water having a greater mass, change their direction less readily and are, therefore, removed by this kinetic action from the steam. The baflles are so constructed that the steam cannot avoid the effect of them so long as a proper water line is maintained within the boiler. At the same time, their arrangement and disposition is such that if it is desiredto use the boiler in a water heating system instead of a steam heating system, they offer no impediment to a proper circulation of. water through the boiler, nor will. they become loaded with solids precipitated from the water.

The invention may be readily understood by reference to the accompanying drawings which illustrate one typical form of section to which the present invention is applicable having my in vention applied thereto.

In the drawings:

Figure 1 represents a vertical transverse section Figure 2 is a transverse section in the plane of line II--II of Figure 1, and

Figure 3 a fragmentary sectional view similar to Figure 1 representing the upper portion of one side of the boiler section, the view being on a scale larger than Figure 1.

In the drawings, 2 designates generally a boiler section having an upper chamber 3. The plane of the normal water line of the boiler is indicated at 4. The portion of the chamber 3 above the water line constitutes a steam chamber, while the portion below the water line constitutes a water chamber. The' section is shown as having a nipple port 5 in the side face thereof, the nipple port being centrally positioned with respect to the vertical axis of the section and being so disposed that a part of the nipple port is below the water line and a part of it above the'water line. Formedin the top of the section at the center thereof, is a steam take-ofi connection 6. The boiler section below the chamber 3 isf ormed with flue parse sages therethrough, the particular section illustrated being shown as having a centralflue l and a side flue 3. The presence of these flues forms on the'inte'rior of the section, water chan nels'll between thefliles 1 and'B, and water channels 'IWbetfeen thef'fiues 8 andthe outsideof the boiler. Below thefi'ues l and 8 there is a water space H' which tommumcats with water spaces [Tin the leg'porti'oris or the; section. It

will'b'e' understood that this section is merely typical'of 'the'generalclassof sections to which the" present inventionperta'ins and that the in-v vention' is not restricted to the particular arrangement of fluesorbthermattersofdesign;

' In the operationbf the boiler sections steam is genera'tedfmuch' morerapi'd-ly the water r channels than inthe'water channels It, so that th'ere"is"an area at'the'water line over these channels 9"where steamleaves the' water at a relatively higher rate than it does from other areas over the water line. Also there is greater turbulence at the water line by reasonjof the upward motion of the currents of water' underlying the surface; "In Figure 3 the arrows below the" water line indicategenerauyftne direction of'fiow'of the waterbelow' the water line, while the arrows in thest'earri space indicate the di rectionoffiowofthe steam.

JAbco'rdingtothe present invention, I provide in the boiler over those areas whre'steam is generated'at a higher rate, baliles 'ISI There are two baill'esl3' shown, one'fbei'ng located at each sid'e' of the verticalcenter'line of the section, one of'thein being locatedinthe area of the boiler over one of the waterbirculating passages 9, and

the'otherof them being similarly locatiecl in the area over theother passage 9;" These baflles i ewhi'ch are generally inclined and preferably curved, have the "lower end thereof terminating below'the pla'ne of the normallwater line. They are inclinedorjcurved upwardly and outwardly from a point" below the normal water line to-" Ward the olitel 'wall's Of the' sec'tion. They 8X- ten'd across the full depth of the "section and, in

the case of a cast iron section, are integrally 1 cast. The steam which is generated at ajhigh rate in the area beneath the bafiles l3 rises from the surface of the water and'is deflected by the 'baffies in a horizontal direction away from the' I steam outlet connection 6.

When the steam clears the bafile, it rises upwardly and then turns horizontally backtowardthe center of the boiler V soj that in clearing the baflie it turns 'through an surface of the water to the outlet.

arc of 180. In leaving the take-off t, it must again change its direction of flow 90 from a horizontal line. In so changing its direction of flow, entrained water particles, being of greater mass, change their direction less readily and are, therefore, thrown out of the steam.

By reason of the fact that the bafiles have their inner lower ends terminating below the normal water line, it is impossible for any steam leaving the water surface in this particular area to by-pass the bafile and flow directly from the Steam is generated at a relatively slower rate in that area of the boiler between the two bafiles and this steam can flow without substantial deflection directly to the outlet. The turning of the steam through an angle of 180 as it clears the bafile results in a considerable amount of the moisture being thrown out, and the reverse flow through an arc of 90 in going from the steam The disposition of the battles in the manner,

described permits of the same sections being used for hot water heating systems where the entire section is filled with water, as it does not restrict the circulation of the water in such case, andby reason of the: inclination or curvature sediment would not accumulate on it to an undesirable extent. Thus the boiler sections are readily adapt-. ed for use in either type of heating plant, notwithstanding the presence of these baffles.

While I have shown and described a particular boiler section and a particular location of the battles in regard to this specific section, it will be understood that the invention may be otherwise embodied and that various changes and modifications may be made within'the contemplation of the appended claim.

A- boiler section havingan upper portion forming a combined steam and water chamber the water line of the boiler defining the separation of th e steam and water chambers, a nipple: port on a side face of thesection openingintotthechamber, the normalwater line beingabove the. bottom of the nipple port, a centrally located ing spaces, said baffles being generally inclined:

upwardly and-outwardly, away. from the center of the section, thelower ends of thegbaffiesnearest. the center, of v. the section terminating .below the water line ofthe boiler section,- the upper outer ends of the bafiles terminating, in the steam, space below the top of the section and inwardly from the side thereof, the, arrangement being. such that steam generated below the baffles is directed in a generally horizontaldirection away from the center of the, boiler and then turns at an angle of approximately 180 back toward the? center of the boiler and is furtherdeflected through a reverse angle ofapproximatelyBO? in passingto the ofitake. I

, LOUIS N. HUNTER.

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