US2566627A - Heater having a helical fluid conveying coil - Google Patents

Description

2 Sheets-Sheet 2.

H. M. PAULSEN HEATER HAVING A HELICAL FLUID CONVEYING COIL Sept. 4, 1951 Filed June 2, 1945 H. M. PAUL-SEN HEATER HAVING A HELICAL FLUID CONVEYING COIL Sept 4, 1951 2 Sheets-Sheet 2 Filed June 2, 1945 Z N V EN TOR.

ATTO/QNEYJ Patented Sept. 4, 1951 UNITED CONVEYING 'QQIL 7 Henry M. Paulsen, Long Beach, Calif.

Application June 2, 1945, Serial No. 597,312

' My'present invention has to do with heaters for raising the temperature of fluids, such as petroleum oils, steam and gases, finding one of its chief uses and advantages as a heater for oils preliminary to passing them to a fractionator for separation of the components.

' In general, heaters for such purposesinvolve tubes through which the fluids are passed,- the tubes being securely mounted in a furnace structure. In conventional heater construction of this type, parallel tubes are disposed one above the other across the furnace, projecting at their ends through the furnace walls and being connected together on the outside by U-connections. In cases wherein the straight tubes are not so supported at their ends in the furnace walls, relatively expensive hangers are required. In either case provision is lacking for free movement of the tube elements due to the considerable expansion and contraction taking place in the tubes and there is no uniformity of velocity or any appreciable turbulence of the flow of the'fluids While passing through the tubes. This shortcoming results in hot spots requiring relative- 1y expensive or high grades of tubing and also results'in deposits on the tube walls which require frequent cleaning. Also, conventional heater construction of this sort is notconduciveto maximum thermal efiiciency and does not permit the use of sectional furnace construction which is so desirable sincethe refractorylining of such furnaces must be repaired and renewed from time to time.

It is therefore among the objects of my invention to overcome those disadvantages as well as to provide additional advantages. More particularly, it is an object to provide a fluid-passing coil helically wound and disposed in a furnace in such manner that the heating flame may be projected axially through the coil in a direction counter'to the flow of fluids through the coil and wherein heat reflected from the refractory walls may be utilized to the fullest advantage. 'Itis also an object of my present invention to provide a device of this character wherein .the fluid-passing tubes are so mounted in the furnace as to provide for free expansive and contractive movement and as to require no hangers.

.It is a further object of the invention to provide fluid-heating apparatus in which the fluids are passed through the tubes with uniform velocity and turbulence and in which the tubes do not require frequent cleaning. When the tubes of my invention do have to be cleaned, which isinot frequently, they may be readily, economically and efficiently cleaned.

It is another object of the invention to provide fluid-heating apparatus wherein. the explosion doors, are disposed in an area not covered by refractory material, 4

3 Claims. (01. 122- 248) Another objeotis to provide fluid-heating apparatus wherein there is minimum obstruction to the free flow of the products of combustion, thus improving the general eiiiciency of the device as well as enabling the use of a relatively short stack for withdrawal of the products of combustion. v 1

Another objectof the invention i the provision of fluid-heating apparatus wherein the heated fluid will leave the apparatus in most efficient condition for subsequent fractionation.

It is a further object of the invention to provide fluid-heating apparatus wherein it is possible to attain maximum tube surface with a minimum of refractory wall surface.

Theparticular spacing of the whorls of th tube from each other as well as'from the refractory walls, which provide unexpectedly improved results, also constitutes one of the features of my invention.

While I have specifically mentioned some of its major objects and advantages, my invention contemplates ad'ditional'object's and provides additional advantages, all of'whichwill become apparent from the following detailed explanation of one of the presently preferred adaptations embraced within the broader scope of my invention as defined by the appended claims.

For purposes of the following description I shall refer to the accompanying drawings, in

Whichf Fig. l is a side elevation, some parts being shown "in section;

Fig. 2 is a section on line 2-2 of Fig. 1;

Fig. 3 is a section on line 3'-3 of Fig. 1;

Fig. 4 is an enlarge'd'section on'line 4-4 of Fi 1;

Fig. 5 is a cross-sectional vie-w showing a slightly modified structure;'and

Fig. 6 is an enlarged perspective showing a fragment of the tube whorl spacer members.

Referring now to Fig.2 of the drawings I show generally at 5 a furnace of circular cross section and comprised'of two semi-circular segments or sections 500,519. The lower section 5b has an arch of fire bricks 6 laid in a semi-circular metal shell i supportedupon legs 8, spacer bricks 9 being embedded in the refractionarylining and spaced apart oircumferentially of the wall.

' The upper section 5a consists of aligned semicircular shell sections ll having radial end flanges Ila secured together by bolts l'lb. Secured to the side edges of the respective sections I! are plates or flanges It which are bolted to parallel flange members [9' carried by the lower shell 6 by'bolts 20. Fire brick lining I5 is carried by shell sections ii, the side edges of the lining being supported'on the inwardly disposed portions of plates l8.

In Figures 3 and 4 is shown a discharge stack 22 for the products of combustion disposed at right angles to the longitudinal axis of the furnace, being in communication therewith through a flue 24. The stack has the usual damper element 2,3, The flue' ha s openings 25 through its side walls, which openings are normally closed by explosion doors 2'! hinged to the flue atZfi to swing relative thereto. The doorsare yieldably held closed by some suitable'means' 'sucht-as a spring not shown. The furnace has an end wall presenting an axial opening at with which the flue communicates, and has an opposite end wall 33 provided with an axial opening 34 in which is disposed the fuel inletnozzle 35.

In Figuresl and 2 my improved fluid-passing coil, generally designated 40, is comprised of a tube helicallyor spirally wound into a cylindrical shape, having a tangentially disposed inlet end 42 -au ,.ouletend 44, d ends passing through openings in the side wallofthe furance.

' In Figs. 1, 2, and 5 the coil is'supported exclusively on the spacer bricks -9, the periphery of the coil being spaced. from the. refractory Wall preferably a distance equal to the outside diam eterof: the ,tube of which the coil is formed. The Whorlsof the coil are also spaced apart a like distance-that is, a. distance equal to the outside diameter of the tube of which the coil is formed. For exampla for a coil formed of 3 inch outside diameterflspirally wound tubin I find ,a furnace whose "refractory walls have an insideldiame'ter of the order of 6'? inches to be particularly suitable, the spacing of the coil from the refractory walls and the spacingrof the whorls from each other beingequal to the outside diameter of the tubing of which the 'coilis formed, or ,3 inchesl To maintain this spacing of the whorls of the tube from each other and yet to allowifor free relative movement resulting from fexpansjionf and contraction, I use U-shaped spacer .membiersifl secured, as by. welding, to a met-als'trip 5|, a v

In a device such as described, constituted :in accordance with 'inydnvention, it will be seen that the hot products ofcombustion pass through the furnace in a directioncounter to the flow of the fluids through the coil, '50 thatthe fluids leave the coil inethe most efficient condition for subsequent} fractionation; This counter flow also allow's the colder fluids'enteri'ng the coils to absorb heat from the colder gases or combustion thus taking advantage of heat usually lost to atmosphere through .the stack. The stack. temperatures are also kept at All tube surfaces are inside the furnace andin inti-. mate contact. with the'productsbf combustion, as well as in position to uniformly take advantage of the heat reflection from 'ther'efractory walls, thus insuring high thermal efficiency. The tur-' bulence and even velocity of flow through the coils eliminates all possibility of .local heating of the, tube, or "hot spotsjf and reduces to a minimum deposition of residue on the tube walls. 'lfhis avoidance of hot spotsrenders it possible to use lower grades oftubing than would otherwise be the case.- The absence of bridge walls and other par-ts acting'as bafiles renders it possible to use a much shorter stack. In fact, in my device, a stack so short as not to require guy; wires or equivalent support may be used. Inasmuch the bottom portion of the lining, said members being disposed longitudinally of the furnace and spaced apart oircumferentially thereof, a cylindrical fluidepassing coil comprised of helically 'woundtubing, said coil being disposed axially in as the coil merely :rests on thespaeer bricks, all a 7 tube hangers are eliminatedrand absolutely :free movement resulting from expansionandcontraction is possible.

the furnace and having its inlet end at one end of the furnaceand its discharge end at the other end of the furnace, said coil being supported by the'spac'er' members in position coaxial with the furnace and with its periphery spaced from the lining a distance equal to the outside diameter of the tubing, combustion means disposed to. pro- ;ject products of combustion axially of the'jcoil in a direction counter to the direction of flow of fluid therethrough, and spacer meansiloose'ly mounted on the coil to maintainits whorls spaced apart a distance equal to the outside diameter of the tubing, said spacer means each comprising an elongated metal strip and U-shaped tube-fen- .gaging members secured to the strip at spaced points therealong.

- 2. .In a fluid heater, the combination of a horizontally disposed cylindrical furnace having a refractory lining, spacer members carried by the bottom portion of the'lining, said members being disposed longitudinally of .the furnace and spaced apart circumferentially thereof, a cylindrical fluidepassingcoil comprised of helically wound tubing, saidcoil being disposed axially in the .furmice and having its inlet end at one end of the furnace and its discharge end at the other end ofthe furnace, said coil being supported bythe spacer members imposition coaxial with the furnace, combustion means disposed to project products of combustion-axially of the coil, and spacer strips loosely mounted on the coil to maintain its whorls in predetermined spaced relationship-to eachiother. 3.1m a flu-id; heater, the combination of a horizontally disposed cylindrical furnace having a refractory lining, spacer members; carried :by the bottom portion of the lining,=.said members being disposed lon tud al y f the. furnace an spaced apart circumferentially.thereof, a cylinxdrical fluid-passing coil comprised. of helically wound tubing,;said coil being disposed axially in the furnace and havingitsinlet end at on 'end of the-furnaceand its d-ischargeend at the other end of the furnace-combustion means disposed to project products of :combustionaxially of the coil, andrspacer means loosely mounted on the coil to maintain its whorl spaced apart a distance equal o the outside diameter of: the tubing; said spacer means each comprising an elongated strip-and Ll-shaped tube-engaging members secured to. the strip at spaced points therealong. V Y

' HENRY M. PAULSEN.

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

' UNITED STATES. PATENTS, .Date

Number Name 624,897 Hall s t Aug. 21,1894 84856.4 Mitchell V Mar. 26,190! 1,266,281 Lapp May 14, 1918 1,804,155 De Florez May 5,, 1931 1,986,258 Erv-in Jan.. 1,-.193\5 2,046,502. Cooke. July 7, 193.6 2,246,469 Lobo June 17, 194];

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