US1779276A

US1779276A - Air heater

Info

Publication number: US1779276A
Application number: US68995A
Authority: US
Inventors: David S Jacobus
Original assignee: Babcock and Wilcox Co
Current assignee: Babcock and Wilcox Co
Priority date: 1925-11-14
Filing date: 1925-11-14
Publication date: 1930-10-21
Anticipated expiration: 1947-10-21

Description

D. s. JACOBUS 1,779,276

AIR HEATER Filed Nov. 14, 1925 2 Sheets-Sheet. 1

a -WVTOR BY $4 9 ATTORNEX9 Oct. 21, 1930. D. s. JACOBUS AIR HEATER Filed Nov. 14

2 Shets-Sheet 2 FJ' 'Z.

cocooccqocccccccoocccccoco qcoccc nnnnn (10C IIS INVENTOR Patented Oct. 21, 1930 ,umw

-mconvs, {on momcLam, NEW

PATENT Lorrie E ASSIGNQR so. was 'nencbcxaatn :mmox GQMPANI, QE-BAYONN NE S Y, A CORP ATION 'QFIIIEWW-TEIQSEY A R 111mm Arli i oetib e vem r Thisinvention relates-to an air heater that is especially useful in connection with waste gases fro'mfsteam boilers, although it is not restricted to thisuse.

'The'inventionwill be'understood from the description in connection withthe accompanying drawings, in which Fig. 1 is a vertical section through a-11 illustrative embodi Inent ofm invention, and Fig. 2is-a horizontal sectlon-alongthe line -2 2 of Fig; 1. The air *heateris shownin connection with enoughof v a steam boiler to-indicate how the sarne isused with such a boiler. Reference character 5, indicatesa bank of tubes of a water tube boiler that is connected to headers 6 and '7', the header 'G'being connected by means" of-the-nipples-8 to the steam and water drum '9', the header 7 *being' connected by means-ofin ipples 10.1to the header 11 which is, inturn, connectedjby the circulating tubes 12 to, the, drum 9, fall in the manner well understoodin this art. I I

3 'The hot products of combustion 'frorn the heater ,'box 16, which is supportedlupon I- 'beams17 that rest upon cross beams 18 which .furnace' (not shown) ofthe'boilerpass across the tubes 5 and the tubes 1-2'into the flue 15,

which'ifs widened-to accommodate the air are, in turn, supported] by means of the uptwo perforated-plates '20 "and 20, which extend fromtheouter'ed-ges of thebox'inwa-rdly right supports-19.

" Thebottom ofthe airy-heater box is madeof to withi n a shortdistance of'each other, and

theup perflend of-theboxcomprises two simi- 'lar' plate's 21"and 211. Two sets of

tubes

22 and 22 "areexpanded'intotheholes in the bot- Y torri and top plates of'the air heaterbox, and plates 23' and 23 which extend entirely across the box Connect theinne'r-ed' es'ofthetop and:

bottom plates','so as toprovif ea by pass ohan- 'ne'l orduct' 28 through the central partof the box, with thetwo sets of tubes located'on' oppositesides of'this channel or duct. "Air 4 ducts or conduits 24 lead into the box 16 on opposite sides thereof'near the top, and-air ductsorconduits 25jand 25 lead away from corresponding sides near the bottom. The

spacesjwithiri which the tubes 22-and 22 arelocated' are provided staggered baflie 14,1925.v semi hex-eases? :

plates

26 and 26 tocause a. pluralityqof; air .passes across the tubes). '5

'Dampers 28 are provided between; the

plates

23 and 23 for thepurposejofaclosing the: by-pass duct 28 between the zplates;23 and 23 in part or-'entirely,;anldga gas'fiue 29 is provided atthe topof theairzheaterybox 16.

A V-shaped troughor catchbasin 30;is pro- -vided on each side of the; flue 1-5 oneside :31 of these troughsbeing parallel with th .SlQP

ing side walls above the, flue 115, and the other side 32 being vertical. I These itroughs are located directly below the sets oftubes 22;.a-nd 22,.and will serveas cinder catchers,; and:wi ll also catch the water that maybe usedato the tubes 22 andv 22,, ;Qutlets from the,

tubes

22 and 22 apluralityofitimes, enter ing through the ducts 24 131 245,. pa sing around the edges of the bafiiQSr26 andfifi,

and. finally. out through the ducts -25-iand 25'. It -:will be; understood that: ducts -25 and-25 will usuallylbe' connectedetoathe same duct, and thatducts' Qiandfl ifimayelso be similarly'connectedlto -.63Ch;;o ther;. Eor instance, if the heateris used to heat-09. 111 1118- tion air for, the boiler furnace, the Waste gases of Whichsupply the heat fiOflShQ-Qflil" :heater, ducts 25 and 25 'maywconnectnto a common duct leading to thecombustion space.

of the furnace. Thetot'a'l quantity iqf' "air to be heated, is thus divided aandxcea h :pa

,heated' by a separate set oftubes422, 22'.

air that is circulating across the outside of the tubes.

By placing the end of the duct 28' and also the ends of the two sets of tubes 22 and 2 directly in communication with the waste gas flue 15, any closing of the dampers 28 will not unbalance the two sets of

air heating tubes

22 and 22, each taking an equal amount of the hot gases, no matter what the position of the dampers. This equalizing of the gas flow is aided by locating the sets duct 28. By dividing the total amount of air to be heated and sending each part over only a part of the total heating surface, the velocity of the air is one-half what it would be if all the air were sent over the same path over all the heating surface and the frictional resistance to flow thus reduced to onefourth what it otherwise would be.

As the waste products of combustion pass upwardly through the flue 15 and spread outwardly on both sides, soot, dust and cinders will collect and drift downwardly into the troughs 30, from which they can be removed through the openings Also, any water that may be used to wash the soot, etc., out of the

tubes

22 and 22 will be caught in the troughs 30 and pass out through the openings 33 without getting into the boiler proper. This is rendered possible because the tubes of the heat transfer device are offset from the direct line of travel of the gases from the boiler.

This invention is particularly useful where a stack draft is used without any induced draft fan, as a much higher capacity can be obtained with the use of the by-pass at peak loads than without the use of the by-pass. When the by-pass dampers 28 are opened the gas which flows through the by-pass will cause the gases in the stack to be hotter than would be the case if all of the gases were to flow through the air heaters, and this in creases the stack draft. At the same time,

the frictional resistance to the flow of the gas as a whole is diminished and both effects combine to give a greater amount of draft at the boiler uptake, thereby making it possible to operate the boiler at a higher rating than without the by-pass. With the par ticular arrangement used, the gases that are by-passed fiow directly upward with a minimum amount of resistance, which makes it possible to operate at a higher rating than would otherwise be possible when the by pass dampers are open.

I claim:

1. A heat transfer device for heating air by hot gases, comprising two sets of gas ducts each set comprising a plurality of small tubes, a by-pass duct, a gas flue connected to the ends of all of said ducts, means to pass separate streams of air over each of said sets of gas ducts, and means to control the flow of gas through said by-pass duct.

2. A heat transfer device for heating air by hot gases, comprising two sets of gas ducts each set comprising a plurality of small tubes, a by-pass duct, a gas flue connected to the ends of all of said ducts, means to pass separate streams of air over each of said sets of gas ducts, and means to control the flow of gas through said by-pass duct, said sets of gas ducts being symmetrically disposed on

oppoof tubes

22, 22 symmetrically around the" site sides of said by-pass duct.

3. A heat transfer, device for heating air by hot gases, comprising two sets of gas ducts, a by-pass duct between said sets, a gas flue connected to the ends of all of said ducts, means to control the flow of gas through said by-pass duct, air ducts having inlets and out lets at opposite ends of said sets of gas ducts to direct separate streams of air over each set of gas ducts, and baffles in said air ducts extending across said gas ducts.

a. A heat transfer device for heating air by hot gases, comprising two sets of gas ducts,

a by-pass duct between said sets, a gas flue connected to the ends of all of said ducts, means to control the flow of gas through said by-pass duct, and air ducts having inlets and outlets at opposite ends of said sets of gas ducts to direct separate streams of air over each set of gas ducts, said air ducts being arranged to direct each air stream back and forth across its set of gas duets, with the air first contacting with the ends of the gas ducts farthest from the gas flue.

5. A heat transfer device for heating air by hot gases, comprising two sets of vertical gas ducts, a by-pass duct between said sets, a gas flue connected to the lower ends of all of said ducts, means to control the flow of gas through said by-pass duct, and air fines to direct separate streams of air over each of said sets of gas ducts, said air ducts being arranged to direct each air stream horizontally across the upper ends of its gas duct and then back and forth to the lower ends of said gas ducts and then horizontally outward.

6. A heat transfer device for heatin air by hot gases, comprising two sets of gas ducts made up of tubes arranged in rectangularly shaped groups, a by-pass duct between said sets, a gas flue connected to the ends of all of said ducts, means to pass separate streams of air over each of said sets of gas ducts by causing the air to enter at the top and leave at the bottom, and means to control the flow of gas through said by-pass duct.

7 A heat transfer device for heating air by waste gases, said device being offset horizontally from the direct path of the waste gases said sides providing parallel walls on opposite sides of the gaspath through said device.

8. A heat transfer device for heating air by waste gases from a boiler, said device being located above said boiler and offset from the direct line of travel of gases from the boiler,

and a catch basin located directly beneath said device.

9. A heat transfer device for heating air by Waste gases from a boiler, said device comprising a plurality of sets of vertical gas ducts offset from the direct line of travel of gases from the boiler with a gas passagebetween said sets of ducts, and a trough beneath said ducts. 7

DAVID S. JACOBUS.