US2651294A - Fluid heater - Google Patents

Description

Sept 8, 1953 Y l R. J. HoRNE 2,651,294

FLUID HEATER R. J. HORNE FLUID HEATER Sept. 8, 1953 2 Sheets-Sheet Filed Aug. 16, 1951 Patented Sept. 8, 1953 UNITED STATES eATENT OFFICE 2,651,294 FLUID HEATER Robert 'Jackson Home, Jenkitowmra. Application August 16, 1951', seria; N0.242,1i5`

'Ihis invention relates to-uid heaters and more particularlyto a-heater having a combustion chamber therein for providing hot water or other liquid for al variety of purposes, such as house heating, domestic hot water supply, process use, and other purposes, and for heating other uids.

The fluid heaters heretofore available, comprising combinations of furnace and heat exchanger, have usually employed natural draft and an inefficient heat exchanger, or induced draft both with constant heat input or on-off control.

The fluid heaters heretofore available have had many serious limitations. heaters, high burning rates must be employed to maintain the stack temperature Yabove the dew point of the Water vapor formed as a product of combustion. The sulphur contentA of the fuel, when burned, produces sulphur dioxide, SO2 which with the water of condensationfproduces active sulphurous acid,` I-IzSOs. This acid attacks the mortar of the stack or chimney, penetrates the interior walls and disintegrates the same and spoils the Wall finish. This acid also forms under light load burning conditions in the 4last passes of the heater and is particularly corrosive to the sheet metal which is frequently used at these locations. Operation at desired fractional capacity is accordingly attended with objectional eifects. When the temperature control no longer calls for heat, the fuel supply is shut 01T. The stack, in many instances, has-been overheated to preclude condensation and in this` condition continues to produce stack draft with forced ingress of air through the heater resulting in van attendant heat loss. Such air, upon its passage through the heatter extracts heat from the liquid in the heater and discharges the vextracted heat with the stack gases. At the same time, the stack is 4cooled down ybelow the ternperature corresponding to the dew point with resultant acid formation. The produetsiofcombustion, because of the hydrogen `content of' the fuel, contain large quantities of water vapor with a. high heat content which passesoif to the stack asafurther loss. y f

The xed heat losses of the heaters heretofore available may be summarized as: v(l)` overhigh stack temperature heat loss, (2) standby stack heat loss, and 3) loss of the higher heat value orfvaporvloss. These losses, as heretofore indicated, are accompanied by destructive vactionof sulphurousacid, and by ineffective heat control and-ineffective heat transfer.;v 1ra;

With many of these .-In accordance with the present invention, a heater is provided whichovercomes the objections tothe prior heaters.

In accordance with the present invention, also, 4a heater is provided with which `the stack temperature is reduced to a minimum by employing counterow heat exchange.

In accordance with the present invention, also, a heater is provided in which the standby stack loss is eliminatetd by use of pressure firing in place'of natural draft.

In accordance with the present invention, also, a heater is provided in which the higher heat values of the fuel arerecovered by recovery of the latent heat of; vaporization in the flue gases.

In accordance with the present invention, also, the deterioration'of the parts exposed to the combustion products is eliminated by the use of highly corrosion resistant materials.

In accordance with the present invention, also, a heater is provided-which does not require a stack because of the use of forced draft, the use of counteroW heat exchange, and the low heat content in the products of combustion which are relatively free from condensible constituents, such as water. Y

In accordance with the present invention, also, a heatetr is provided in which the hazards of explosions and leakage of gas is eliminated.

In accordance with the present invention, also, a heater is providedhaving a controllable widely variable heat output.

Other objects and advantageous features of the inventionwill be apparent from the specification and claims.

' The nature and characteristic features of the present invention will be more readily understood from the following description, taken in connectionv with the accompanying drawings forming part hereof, in which: l

Figure 1 is a vertical rcentral sectional View through a preferred embodiment of a heater in accordance With'the invention, taken approximately on the line I`-l of Fig. 2; and

Fig. 2 isa horizontal sectional view taken approximately on the line 2-2 of Fig. 1, parts being shown in plan'tovillustrate the details of construction.

It should, of course, be understood that the description and drawing-herein are illustrative merely, and that various modifications and? changes maybe madein the structure disclosed without departing from the spirit of the invention.A -1 Y .Y Referringhnow more particularly to the drawings, a cylindrical housing I D is provided, of metal, having a vertical side wall II and a bottom wall I2 connected thereto in any desired manner such as by welding. The bottom wall S2 is preferably provided with a downwardly disposed or dished portion I3 for purposes to be explained.

The side wall Il is provided, near the bottom thereof, with a hanged fluid. inlet pipe i4 for the delivery into the heater of the fluid to be heated. rlhe upper extremity of .the side wall li is provided with a horizontal peripheral flange I5 which is adapted to have secured thereto, in fluid tight relation, a top closure wall i6. A gasket, t1. is preferably interposed between the top wall I6 and the flange I5 and bolts I8 maybe provided for removeably holding .the top wall `I6r in posi--Y tion. At the central portion of the top wall I6,` a removeable cap I9 is provided having a flange 20. Studs 2| secured to the top wall I6 and extending through the flange 261 preferably have nuts. 2l thereon, for removeably holding cap- I3 position. A gasket 2.2 is. preferably interposed between the flange 2'Ilf and the. topiI wall I6.

The cap I31is preferably provided` with anopening 25' which is closedby a resilient gasket `25, of

fluid tight material such: as rubber, natural or synthetic, through which av burner 221i extends, the opening 25 permitting: the withdrawal of the burner 21 if desired or required The burner 21 preferably includes an exterior flanged flaring tube 28v for: the delivery of. air under pressure,.and in the interiorfof the tube 28, a haring fluid delivery tube 29` is provided, to which fuel under pressure is delivered by a pipe 3U.

The burner 21 is adapted to be secured to the inlet of a combustion. chamber.r 35,. preferably having a threaded connectionB permitting as;- sembly and removal.

The combustion chamberI 35x is preferably of U-shape and tubular and includes a vertical cylindrical section 3X1" made of temperature change and heatV resistant glass, with a.: flaring rim 38 with `whicha clamping ring 39: is in engagement. The ring 39 has a plurality' of clamping arms '40: which extend through the cap t5 and have. nuts 4I- on the outer end thereof for clamping, and a spacer sleeve 32 is provided for maintaining the spaced relation of the burner 21.

At the lower part of the ver-tical cylindrical section 31 of the combustioni chamber 3,5, a U-shaped section 42 is provided, at the lower part of which a drain pipe 43 is connected'. The section 35 preferably has a, ring 44,A of resilient Inaterial such as rubber, vinterposed between its exterior, and the interior face of the dished portion I3 for accommodating expansion and preventing breakage upon occurrence of shock. The space surrounding the lower end of. the section. 42, in the dished portion I3, and outside the ring 44 may, if desired, be lled with sand, as at 3l., for further cushioning and support.

In order to prevent Vleakage at the drain pipes 43, a sealing plate 42a may be provided, for the reception of a sealing gasket 33. A sealing plate 42h, in engagement with the gasket 33 is preferably also provided and held in` compressing relation to the gasket 33 by nuts 34 on studs 34a.

Within the interior space in the housing I0, a plurality of spiral units 45 are provided, each having an inner or central manifold section 46. The manifold sections 46 are disposed in vertical alinement, have ground or other uid tight joints 41a therebetween, and constitute a portion of the combustion chamber. At the upper end of the uppermost manifold section 46, a closure 48 is provided. A cushioning block 49, of resilient material such as rubber, is interposed between the closure 48 and the cap I9.

Each of the manifold sections 45 is made of temperature change and heat resistant glass and has extending therefrom a glass tube 45a, disposedin aspiral path ina. plane, and the respective tubesf45a' being arranged one above another. The tubes 45a are preferably terminated contiguous to the inlet pipe I4. The tubes 45a., are pitched downwardly to a slight extent towards their outer ends for drainage and at their outer ends, are. each connected to tubular manifold sections M6; of; glass, and similar to the manifold sections 46;-in vertical alinement.

In the space below the lowermost tube 45a, a cushioning ring 50, of resilient material such as rubber, is provided for supporting the tubes 45a and resisting shocks'.

At; the upper' endY ofthe uppermost manifold section; I 46, a gas. dischargeconnection 5I is provided which may be connectedy to any desired location for the discharge of the gases of combustion.

The connection 5I has a shoulder 52 for engagement with a resilient cushioning ring- 53. Mounted on the top-wall I6, a closure ring 54 is provided, having a lower ange 55, an upper ange 5t? and an inwardly extending flange 51. The lower flange 55 is adapted -to be removably connected to the top wall I6 by studs 56- and nuts 55,. a.. gasketl 60 being interposed. between the flange 55 and the top wall I6.

The flange 51 is adapted to have the: cushioningring 54 in engagement therein-1th and on the vopposite side an inner sealing gasket. E3, and an outer sealing ring gasket 5l held in position by a sealing, plate 62 are provided for preventing fluid leakage.

Boltsv 63, extending through the. ange 56 and the plate 62 hold the plate 62. in position and compress the gaskets 60 and (i2` At the lower end of the lowermost manifold section 4.8-, aliquid discharge pipe or connection 65 is: providedfor the discharge of condensate from.. the products of. combustion, as. hereinafter explained. The discharge connection 6.5. has. a shoulder BV for engagement with. a, resilient cushioning ring 6,1. Secured to the bottom wall 1.2 a clamping plate. 68 is provided with which a sealing gasket 63 is adapted to engage, a sealing plate 10 being provided for compressing the gasket 69. LStuds 1I and nuts 12 provide for tightening the plate 10. and compressing. the gasketr 69.

The pipeY 65 is connected to a drain pipe 13 having an upwardly extending leg 14 connected to an upwardly extending leg 1-5- which in turnis connected to the drain pipe 43.

At the top of the legs 14 and 15 a fluid discharge pipe 16- is. connected for determining the water level at the lower part. of the combustion chamber 35 and for delivery of condensate, as hereinafter explained.

The top closure wall I6 is provided with a outlet connection 11 for the heated liquid.

The Inode of operation will now be pointed out.

Fuel under pressure is supplied through the fuel pipe 3D to the burner 2.1, and air under pressurer is supplied to the burner 21 `for delivery through kthe pipe 2B. The fuel and4 air thus delivered to the combustion chamber 35 is. burned in that chamber and while burning passes downfluid wardly in the vvertical section 32, around through the section 42 `and upwardly through the manifold section 46. A portion of the liquid'in the section 42 is vaporiz'ed by'theradiant heat of combustionv in the section 3'| and the llame Aand hot gases in contact therewith. In thev manifold sections 46, the hot gases of combustion are divided into a pluralityof streams and 'pass outwardly'through the spiral tubes '45d and'jto the manifold sections|46for dischargefthrough the discharge pipe 5|. u

The fluid to be heated is delivered through the inlet pipe I4, passes in lheat-exchange relation with the exteriors ofthe manifold sections |46, with the spiral tubes 45a. in an inward spiral path along these tubes, with the manifold sections 46, and with the combustion chamber section 31, and pass out through the outlet pipe 11.

Upon the completionof combustion, the-water vapor producedas a result ofthe combustion of the hydrogen-content of the fuel and the water vaporized in the section 42 passes with the other gases of combustion through the spiral tubes 45a. The gaseous streams in thei-rpassage through the spiral tubes 45a are drastically reduced in temperature and condense. The condensate passes outwardly in the spiral tubes 45a to the manifold section |46 where it is delivered to the discharge pipe 65. A high heat recovery from the fuel is thus achieved by utilization of the latent heat in the condensate which is available because of the low temperatures of the gases before discharge.

The lower part of the combustion chamber 35, because of the connection of the pipe 65 thereto preferably contains water which is available for vaporization in the combustion chamber 35, and for subsequent condensation in the outward passage of the hot gases through the tubes 45a. The pipe 16 prevents the water level in the combustion chamber 35 from rising too high and maintains the level at the desired location.

The construction of the combustion chamber 35, the spiral tubes 45a, and the manifold sections |46, of glass of the proper characteristics, prevents corrosion by sulphurous acid formed as a result of the combustion of the sulphur content of the fuel.

I claim:

1. A fluid heater comprising a closed casing having a fluid inlet and a iluid outlet, a combustion chamber centrally disposed in said casing, a burner at one end of said combustion chamber having fuel and air delivery connections for the delivery of air and fluent fuel under pressure, a first manifold in said casing in communication with said combustion chamber, a second manifold in said casing spaced from said first manifold and having a gas discharge pipe, and a plurality of tubes connecting said manifolds, each of said tubes being of spiral configuration and downwardly pitched toward the outlet end of said tube, and each of said tubes being in engagement with contiguous tubes above vand below to provide a spiral path for the fluid to be heated.

2. A fluid heater comprising a closed casing having a fluid inlet and a iluid outlet, a combustion chamber centrally disposed in said casing, a burner at one end of said combustion chamber having fuel and air delivery connections for the delivery of air and fluent fuel under pressure, a rst manifold in said casing in communication with said combustion chamber, a second manifold in said casing spaced from said ilrst manifold and having a gas discharge pipe, a plurality of tubes connecting said manifolds, each of said tubes "being of spiral configuration and downwardly inclined toward'the outlet end of said tube,and each of said tubes being inr engagement with contiguous tubes above and below to provide aspiral path for the fluid to be heated, a liquid connection at the lower end of said combustion chamber, a liquid drain connection at the lower end of said second manifold, and connections between said liquid connections for determining the-,liquid level in thelower part of said combustion chamber.

3. A fluid heater comprising a closed casing having a fluid inlet and a fluidoutlet, a combustion chamber centrally Vdisposed in said casing, a burner at one end of said combustion chamber 1 having fuel and air delivery connections for the delivery of air and uent fuel under pressure,

a manifold in said casing having a gas discharge pipe, a plurality of tubes of spiral configuration connecting said combustion chamber and said manifold, each'of said tubes being downwardly pitched toward the outlet end of said tube,`and each "of said tubes being in engagement with contiguous tubes above and below to provide la spiral path yfor the fluid to be heated and a liquid drain connection at the lower end of said manifold.

4. A iluid heater comprising a closed casing having a. fluid inlet and a iluid outlet, a combustion chamber centrally disposed in said casing, a burner at one end of said combustion chamber having fuel and air delivery connections for the delivery of air and fluent fuel under pressure, a manifold in said casing and having an upwardly extending gas discharge pipe, a plurality of superposed tubes each of spiral configuration in a horizontal plane connecting said combustion chamber and said manifold, each of said tubes being downwardly pitched toward the outlet end of said tube, and each of said tubes being in engagement with contiguous tubes above and below to provide a spiral path for the fluid to be heated, and a liquid connection at the lower end of said combustion chamber.

5. A fluid heater comprising a closed casing having a fluid inlet and a fluid outlet, a combustion chamber of U-shape centrally disposed in said casing, a burner at one end of said combustion chamber having fuel and air delivery connections for the delivery of air and fluent fuel under pressure, a ilrst manifold forming part of said combustion chamber, a second manifold in said casing spaced from said first manifold and having a gas discharge pipe, a plurality of tubes connecting said manifolds, each of said tubes being of spiral configuration in a horizontal plane, downwardly pitched toward the outlet end of said tube, and each of said tubes being in engagement with contiguous tubes above and below to provide a spiral path for the uid to be heated, a liquid connection at the lower end of said combustion chamber, a liquid drain connection at the lower end of said second manifold, and connections between said liquid connections for determining the liquid level in the lower part of said combustion chamber.

6. A fluid heater comprising a casing having a top and bottom wall and a vertical side wall therebetween, a fluid delivery inlet in the lower part of said side wall and a fluid discharge outlet in said top wall, a vertically extending combustion chamber of U-shape centrally disposed in said casing, a burner at one end of said combustion chamber having fuel and air delivery connections for the delivery of air and uent fuel under pressure1, a, rst manifold 4`in saicl'ceringfv forming part ofi said combustion chamber, a. seo.- ond' manifold in said casingspaced from said first. manifold and havingv an upwardly extending gas discharge pipeZ and a plurality of' superposed tubes each of spiral configuration ina horizontal plane connecting said manifolds, each of said tubes being downwardly4 pitched toward the outlet end: of said` tube, and each ofl said tubesbe.- ing in engagement with contiguous tubes above and below to provide a spiral pathfor the iiuid to be'heated.

s 7 A u-id; heater comprising a casingA having atop and bottom Wall and a vertical side Wall therebetween a iiuid delivery inlet in` the lower part of said` sidewall and a fluid discharge outlet in said` top wall, a vertically extending oombuston chamber of U-shape centrally disposed in said casing, a burner at one end: of. said combustion chamber having rfueland air delivery connections for the delivery of air and. fluent fuel under pressure, a rst manifold in. said casing forming part of said Ycombustion chamber,A a second manifold in said casing spaced from said rst manifold and having an upwardly extending gas discharge-pipe, aplurality of superposed tubes each of, spiral, configuration inA a horizontal plane connecting said manifolds, each of said tubesbe ing downwardly pitched toward, the outlet end of said tube, and each of -saidtubes being in engagement with contiguous tubes above. and below to provide a spiral path for the iiuidl to be heated, a liquid connection at the lower end of said combustion chamber, a liquid drain connection atvthe lower end of said second mani-fold. and connections between said liquid connections for determining the liquid level in the lower. part of said combustion chamber.

' ROBERT JACKSON HORNE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date.

2,046,813 Dunham et al'.. July 7, 1936 2,581,316: Wolfersperger Jan. 1, 1952 l FOREIGN PATENTS Number Country Date 2,558 Great lBritain Oct. 19, 1-860 133320 Great Britain June. 28,i 1905

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