US1771995A - Air preheater - Google Patents

Description

H. R. CARR AIR PREHEATER Aug. 5, "i930,v

. 1928 3 Sheets-Sheet 1 vFiled Oct. 22

ILJYN L.

' 1%ENTOR M ATTORNEYS Aug. `5, 1930.

H. R. CARR AIR PREHEATER Filed OGC. 22, 1928 "3 Sheets-Sheet 2 lv/ENTOR yBY fm ATTORNEYJ Aug. 5, 1930. H, R. CARR AIR PREHEATER Filed oct. 22, 1928 3 sheets-sheet 3v f lNVENToR BY WA Patented Aug.- 5, l1930 UNITED STATES vPATENT OFFICE HUGH R. OARR, 0F NEW FOR-K, Y., ASSIGNOR TO INTERNATIONAL COMBUSTION EN- l OINEERING CORPORATION,OFNEW-YORK, N. Y., A COBPORATION OF DELAWARE(` AAIR PREHEATER Application tiled October 22, 1928, Serial N 6.314,035, and in Germany April 4, 1928.

I This invention relates to improvements in air preheaters suchas are used inconnection with furnaces and subject to the heat of the waste gases. j

One of the primary objects of-my lnven- .tion is to provide an air heater which may be installed in places where the usual. forms of heater could not be effectively installed because of 'space limitations and the like.

Another object of-my invention'is to provide-al heater of the character'described in which effective distribution of the air through the heater is obtained.

A more specic object of my invention is the provision of-a vsplit air preheater having central admission of air and outside disboiler installation showing an application of my improved air preheater, the section through the air preheater being taken on the line 1--1 of Fig. 2.

the section being taken substantially on the line 2 2 of Fig. 1.

Fig. 3 is a view similar to Fig. 2 but illus? trating a modification of my invention.;

Fig. 4 is a plan section taken on the linev 4 4 of Fig. 3, and

Fig. 5 is a view similar to Fig. 2 illustrating another modification of my invention. l

The boiler installation illustrated in Fig. 1 comprises, in general, a combustion chamber A having Aits side, front and top walls defined by the rows of finned water tubes 6, 7 and 8, respectively. A row of tubes 9 extends across the bottom of the combustion chamber, the tubes bein -spaced sufficiently apmart to permit gravitating ash to pass freely therebetween. At the rear of the combustion cha'mber'is arranged a boiler unit B which comprises an upper drum 10, a lower drum 11, and av plurality of tubes connecting is divided into two sections. Fig. 2 1s a rear \v1ew of the air preheater,

the drums. Suitable b'afiiing is provided to cause the gases t take a tortuous path amongst the tubes of the boiler unit B. The front row ofconnecting tubes 12 constitutes the rear wall of the combustion chamber A,

and it is to be noted that the tubes of this.

row are provided with fins terminating short of the upper drum 10 so as to provide an out- `let 13 for the gases of combustion. A superheater 14 may /be located in one of the passes of the boiler unit B. i

v After leaving the boiler unit B the gases pass downwardly into the'space 15, then upwardly through an air preheater C, and from thence pass to the stack or flue 16.

. A plurality of burners b are employed for introducing pulverized fuel and air into the combustion chamber, the burners preferably being located in the lower portion of the combustion chamber'and at the corners thereof.

The air preheater C is what may be termed a split heater and comprises two sections 17 and 18, i. e., the casing structure of the heater. Each section is provided with a bottom gas inlet 19, a top Agas outlet 20, a side air inlet 21 and a side air outlet 22. Each section is also provided with 'means lfor dividing its interior into a plurality of gas passages and a plurality of air passages.

In this instance I have illustrated for this purpose a ,plurality of hollow plate-like members 28 which are spaced -apart to 4provide passages 24 therebetween (see Fig. 4). As shown, the passages -24 are for the gasesand the hollow plates are for the air. While I have described the passage as being provided by spaced hollow plate-like members. it is to be understood that I also contemplate employing spaced round tubes for this purpose.

Referring now more particularly to Fig.

2, it will be seen that the gases from the chamber pass into the sections 17 and 18 through the gas inlets 19 which are common to the lurality of gas passages in the sections. he gasesleave the plurality of passages through the common gas outlets 20, from which outlets conduitsor manifolds 25, 25, lead to the intake of the induced draft fan 26. From the fan the gases are exhaustedinto the stack 16.

i The air which is passed through-'the heateris introduced by means ofa forced draft fan'27 Which discharges into a conduit 28' Aconstituting a common intake for the air in- `lets 21, 21 of the sections.

I lets 22 which are in the opposite side of the lustrated the conduits 29 as leading sections from the inlets and finally is passed to the point or points desired through suitable conduits 29.k In this instance I have ilburners for the purpose of introducing preheated air into the combustion chamber at the burners.

By providing a split air heater in which the air enters in the middle, passes through the heater, and passes out at the outside, i. e., passes out through outlets arranged in the sides opposite to the sides having the inlets, even distribution of air through thefheater is obtained, and this makes for efficient heat transfer. v- This Will be readily understood by referring to the rows of arrows 30 and 3l in Fig. 2 from which it Will beseen that all of the air passing through the heater has the same distance-to travel, in consequence of which even distribution and heating are effected. r

` My improved air preheater adapts. itself very Well for use in installations Where thespace left for the heater is rather limited because the, heater need be no Wider than the number of heating elements, i. e.holloiv plates or the like, required to give the necessar amount of pre-heat. This is made possib e because the common air intake is central of the heater, and Within its thickness, and the outlet ducts are at the ends. As the heating elements run parallel with the back of the furnace access may be had thereto from the aisles at the sides of the furnace in cases `where the heater must occupy the entire space in back of the boiler. The arrangement is thus adapted for use in places Where, because of space limitations` it is either impossible to to the ifffvnees" provide a usual form of heater of adequate size or to provide connections for the usual forms of heaters in a manner to insure maX- imum effectiveness of such heaters. The necessity for diffusers is obviated, the heater itself functioning as its own diffuser.

It is to be noted that in a heater arrangement constructed in accordance With my invention the fan 27 may be conveniently located in the space between the gas discharge ducts 25, 25 leading from the section 17 and 18 tothe induced draft 26. The fans 26 and 27 may be mounted on a support above the lboiler such as the building structure from which the boiler unit B is hung. The duct arrangement for the fans is very simple. Also the conduits 29 leading to ,the burners are of very simple form due tothe convenient locationsof the air outlets in the sections 17 and 18.

In the modification illustrated in Figs. 3 andy 4, I have shown the air inlets 21*iL adjacent 'the bottom of the sections 17a and 18 andthe air outlets 22EL adjacent the top. In this case the Waste gases enter the heater at the top and leave at the bottom.

In themodification of Fig. 5 I have shown the sections 17` and 18c inclined, i. e., the bottom'p-ortions of the section are brought, together and the top portions are spaced apart. The common intake 28 is located in the space between the sections. a Byv bringing the lower ends of the sections together spaces are provided-at the sides' for the location of the delivery conduits 29c so that a very-conipact heater not only as to thickness, as prey viously described, but also as to Width', is provided. The conduits 29c by this arrangement are kept Within the Width of the heater as will be clear from the dot and dash lines a and a Which may be considered as indicating the location ofthe sidewalls of a narrow installation. This arrangement, because of bringing the gas inlets 19c together, may also be advantageouslyemployed Where the gas duct or chamber *15 is relatively narrow.

It is to be understood that 'I also contemplatehaving the heater arranged so the air may enter at the sides and leave at the center, in which case the air outlets 22 would become inlets and the air inlets 21 would become outlets.'

' In all forms it Willbe seen that the construction is simple and the number of connections required reduced to the minimum'.

I claim:` A

A'split air preheater of the Waste gas type comprising two'sections each having means providing a plurality of gas passages interspersed with air passages, a gas inlet at one end, aV gas outlet at the other end, an air inlet in one sid'e'adjacent one end, and an air outlet in the opposite side adjacent the other end, said gas inlets and outlets being common to the pluralitypf gas passages, and said air inlets and outlets being common to the air passagessaid sections being inclined with their adJacent edges at the ends having the Y air outlets close togethei" and with. a'sbstantial space therebetween at the ends having the air inlets and the sections being so positioned that the air inlets face each other an air intake manifold Common to the air intakes and located in seid space, and air outlet manifolds for the air outlets.

In testimony whereof I have hereunto signed my name. A

HUGH E. GARR.

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