US2249587A - Tube displacer - Google Patents

Description

R. H.1Y'ILGHMAN ETAL 9,

TUBE DISPLACER I Filed Jan. 28, 1939 2 Sheets-Sheet 2 July 15, 1941 Patented July 15, 1941 s Richard H. Tilghinan, East Orange, .NL- j.,' 'and Ervin G. Bailey, .Easton, Pa., assignors to The Babcock &. Wilcox Company; Newark, N. 1.,

a corporation of'Ne w Jersey Application Jams-2s, ia slseri i Nolzsazio,

: -.'Ihe presentinvention relates to, improvements in the-construction and operationoffiuidlheating apparatus,.and more particularly to liquidtheate ers :and .vaporizers' in which cores. or. displacers are employed in some .of the fluidzheati-ng. tubes tol reduce the effective; cross-sectional .fiowi area thereofand thereby increase the liquid-.contact with the. tube walls, to minimize thepossibility of:overheating of thetubesv :....The'g.eneral object of our 'inventionis the'provision. of an improved construction and arrangement of a :core for the purposedescribed. A more specific object is the provision of a fluid heating tube core constructionwhich-is characterized by its-effectiveness in use, simplicity-of design, relatively low cost of construction; and ease of installation and removal. 'A further specific-object is the provision of a vapor generating tube core arrangementwhibh provides the desired reduction in effective flow area and-permits of a high rate of heat transfer to-the liquid in the tube over substantially all of its-surface and particularly from the portion of the tube wallmost liable to overheating-and insures-maxheat absorbing capa'city'within safe oper- -'.E'he various features of novelty which characterize our invention are pointed out-with'particularity in the claims annexed to and-forming a part of this specification. For a better understanding .of theinvention; its operating advantages and specific objects; attained'byits use, reference should be had to the accompanying drawings and descriptive matter in which we have illustrated and described a preferred 'embodiment of the invention: Of the drawings: j Fig.1 is a sectional elevation of a steam boiler unit in which the invention may be employed; j

Fig, 2 is an enlarged View of the furnace floor tube shown Fig. 1-; g h A "Figsi 3 and 4 are sectional views-taken on-the lines 3-3 and 4-4 respectively of Fig.2; and Fig. 5 is a longitudinal section through the wall of the flexible tubing. U 3 .In Fig. 1 is illustrated a waterstube steamboil er ,of the-.integralifurnacetype, such as isdisclosed in .U. -;S., Patent -1,999,98 l-." --The.;steam boiler illustrated comprises; a yertieal'lygisposed bank; of steam generating tubes; I 0. extendin ree i en l arran ed p rm r drums'l l and l2 -respecti vely Th and "arearrang'ed alon 6111 13 sett n iiwah ithe rema mng erima there;-

aratedfromthe space containing the tube bank by arow ofpartition-forming tubes l4 except at therear end. As indicated in Fig. 1. the furnace illustratedv is fired by .a pluralityof fluidiuel burners 15. arranged in the front Wall. The/furnacefioor is water cooled by a row.of...water tubes ZU extending ata slight horizontal inclinationfrom thelower drum E2 to a header 2i below the 'outerside wall of the furnace. A row of "Water tubes 22 extends along the outer side wallandroof of the furnace and oonnectthe header 2! to the upper drum H. The tubes 20 and 22 are similarly spaced apart longitudinally of thefurnacev The spaces between the floor tubes 26 areclosed by floor blocks of heat resistant material held in position on and transmitting heatfrom the furnace chamber to the tubes ill. e

In normaloperation a portion of the'tubes at the front end of the tube bank ill serves as down; corners, permitting a water flow from the upper drum 'to the'lower drum If. The lower drum supplies all of the floor tubes 20 with water which is-delivered to the side wall header 2| and redistributedtherein to the tubes 22, through which it flows together with any steam generated to the upper drum H. The rate-of fluid flow through'tne fioor tubes 20 depends upon the "pressure'differential created by the difference in densities of the fluid in the vertical conduit portions connected to the opposite ends thereof. Undercertain operating conditions the rate of fluid circulation through the floor tubes 20 may 'be"'so 'low as t0fai1 to displace steam bubbles collecting in the upper portions of the fioor tubes. f In order to maintain the wall temperature of vapor generatingtubes within the desired range,

itfis important that the internal peripheral surface of thetu'bes, and particularly the portion where vapor bubbles tend to collect, and especially so. if these wall portions have the highest rate of heat input, be maintained Wet with liquid for the mosteifective heat transfer conditions. This maintenance of wetness is particularly difficultiwhenjthe tube is arranged in a horizontal or 'horizont'allyinclined position, as when used as, a floor tube as the vapor generated therein tends'to separ'ateand concenrate in the uppermost por'tionof the tube which is subject to the most intense heating. A In al cordance with our invention each of the na rtubes zn in which'displacement or; stagnant steam bubbles or' prevention of dry spots' is as. sired, is provided with a core or displacer for reducing the effective fluid flow area therethrough arranged therein so as to provide an effective flow area causing an increased liquid contact with the upper part of the tube wall. As shown in Fig. 2, the ends of each tube 20 are expanded into the drum I2 and header 2|, the inner side of the drum wall being counterbored as indicated. The tube core consists of a body section 25, preferably formed of flexible steel tubing, as shown in Fig. 5, adapted to be put under tension. Each end of the core tubing is provided with a fastening device for detachably securing the core in its desired position. As shown, the drum or upstream end of the tubing has the larger end of a streamlined plug 26 inserted therein and held in position by a pin 21 extending through the tubing and plug. The plug 26 is formed with a narrow projecting hook 28 extending beyond and around the expanded end of the tube 20. The hook portion 28 is adapted to engage a bar 29 welded on the inner side of the drum wall below the tube opening. Th plug 26 is cut away, as indicated in Fig. 2, to provide a small opening 30 connecting the interior of the tube 20 and the interior of the tubing 25. The header or downstream end of the tubing 25 is also provided with a streamlined plug 3| having a more gradual taper than the plug 26, and which is held in position therein by a pin 32 and terminates in a projecting hook 33. The plug 3| is also cut away to provide a passage 34 similar to the passage 30 at the other end of the tubing. 7

The described core construction facilitates the installation and arrangement of the cores in the tubes. drum l2 through a man-hole in one of the drum end walls and inserted into thecorresponding floor tube until the hook 33 extends over the header end of the tube and contacts With the wall of the header 2| below the tube end. The

sprung into position to aid in keeping it in that l" position. The core and associated parts are constructed and arranged so that the core will ex tend along the bottom of the floor tubes. This eccentric position relative to the tube is preferable as it displaces the flowing water upwardly 1 and forces it into contact with th upper portion of the tube wall moving any stagnant steam bub- Each of the cores is brought into the: I

bles and wetting the wall portion which is more liable to be overheated than the portion con-'- tacted by'the' core. In effect, the central axis of j the effective flow area of the tubes is raised to a point above the geometrical center of the 'tube. The streamlining of the plugs 26 and 3| tends to 'prevent liquid flow resistancewhich would reduce the rate of circulation through the tube 20 by minimizing eddy'cu'rrents at the ends of the core. The core'openings 3D and 34 aid in maintaining the core in its intended position'on' 'the' tube bottom, by permitting the entry of water into the tubing 25 and thus offsetting any tendency of the core to float upwardly. The core construction describedis adapted for use in'not only various typesof existing fluid heaters for improving the circulation therein, but also ne'wfluid heater installation's wherefor various reasons tube diameters are employed which 'ren'der'th'e use of cores advantageous.

Whil'einaccordance with the provisionsofthe statutes we haveillu'str'ated'ahddescribed herein the best form of theinvention now'kn'own to us,

those skilled in the art will understand that changes may be made in the form and arrangement of the device disclosed without departing from the spirit of the invention covered by the claims, and that certain features of th invention may sometimes be used to advantage without a corresponding use of other features. For example, the core can be made progressively increasing in cross-section towards its downstream end, where the quantity of vapor bubbles present tends to increase towards that end.

We claim:

1. A flow area reducing core adapted to be inserted in a fluid-conduit comprising a hollow elongated elastic body member and means mounted on each end of said body member for detachably holding the core under tension in positionin the conduit.

2. A flow area reducing core adapted to be inserted in a fluid conduit comprising an elongated body member formed of flexible tubing adapted to be put under tension and end members connected to the ends of said flexible body member and having a hook-shaped extension for holding the core in position.

3. A flow'area reducing coreadaptedto beinserted in a fluid conduit comprising an elone gated body member formed of flexible tubing adapted to be put under tension and a streamlined end member mounted in each end of said flexible body member and having a hook-shaped extension for detachably holding the core in position in the fluid conduit.

4. A flow area reducingcore adapted to be in-.- serted in a fluid conduit comprising an elongated body member formed of flexible tubing and astreamlinedend member mounted in each end of said flexible body member and having a hook-shaped extension for holding the core in position, said body member having an opening therein for the entry of fluid from the fluid o u P 1 5. In a fluid heater, a pair of spaced fluid containers, a tubular 'fluid conduit having its opposite ends connected to said containers, and a flow area reducing core having a hollow elongated elastic body memberarranged in said tube and having end fasteningmeans thereon extending intoland detachably engaging said containers for holding. said body member under tension in a predetermined position in said fluid conduit.

6, In a fluid heater, a pair of spacedfluid containers, a tubularfluid conduit having its oppositeends connected to said containers, a flow area reducing core formed of flexible tubing adapted to be put under tension arrangedin said conduit, and fastening means on each end of said core arranged to extend intosaid containers for holding said core under/tension in said co u r 7. In a fluid heater, a pair ef'spaced fluid containers, a'tubular fluid conduit havin its opposite ;ends;connected.- to said containers, .a .flow area reducing; core formed of fiexible-tubing'and eccentrically arranged in said conduit,and fastening means on. each end ofsaid'Icore arranged to extend over the .ends'of'said conduit and engage the-walls-of said containers to hold said core inposition in sa'id-con'duit. 7 -BJIn-a'fluid heater, apair of'spacedfluid containers, a substantially horizontal floor tubehaving'its'oppo'site ends connected to said containers,

a flow area reducing core jormedpf flexible tubin: andie en c 'a a eedia n the ptt of said tube, and fastening means on each end of said core arranged to hold said core in position.

9. In a fluid heater, a pair of spaced fluid containers, a substantially horizontal elongated floor tube having its opposite ends expanded into said containers, a flow area reducing core formed of flexible tubing and eccentrically arranged along the botttom of said tube, and hook-shaped fastening means on each end of said core arranged to extend into and engage said containers for holding said core in position under tension.

10. In a fluid heater, a pair of spaced fluid containers, a fluid heating tube having its opposite the length of said tube and means for holding said tubing in spaced relation with the heat absorbing side of said tube including means for fastening said tubing at least at on end to one of said fluid containers.

RICHARD H. TILGHMAN. ERVIN G. BAILEY.

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