US1484463A - Air preheater - Google Patents

Description

- Feb. .19 Y1924., 1,484,463

' H. E. BEEDE AIR PREHEATER` Filed Sept. 6, 1922 lzwmw www mi /a @if www www@ Patented Fein i9, lgli innrsosrarss HER-MAN E. BEEIDE, Ol@ AR-NGTOIT, MASSACHUSETTS.

AIR PREHEATER.

Application filed September 6, 1922.

To all whom t may concern: l

Be it known that I, HERMAN E. Bruton, a citizen of the United States, residing at Arlingtoninthe. county of Suffolk and State of Massachusetts, have invented certain new and useful improvements in Air Preheaters, of which the following is a clear, full7 and concise description.

My present invention relates to `air preheaters, and more particularly air preheate-rs to use in combination with pipeless furnaces, stea-ni, hot water, in fact, any kind of a. heating, apparatus in which coinhustihle fuel is used as` hard coal, soft coal,

coke and the like.

The heat-ing apparatus which is in use universally to-day is of the old and well known type consisting,- of an ash pit, grate, re looX and iiue, and when using coal, gases accumulate over the lire and if not carried ofi or lourned will result in a minor explosion. To take'care of this zgas, the average heater is provided with an air inlet usually through the coal door over the fire box. Air enters through the openings so provided in the door and to a small extent iniXes with the gases over the re and thus allows soine of the gas to burn while the-'greater part goes up 'the flue without doing any work whatever, and there is no way with this apparatus that more air can bei admitted without cooling' down the firevbecause before the air will ignite with the `rases it niust reach a critical temperature, and coming; as it. does from the front of the heater, through the door, it cannot become hot to the combustible point if a sufficient amount is admitted to mix with all the gas generated from the lire.

ln my present invention l have ohviated these objections existing` in the present day structures of this type, and have developed a pre-heater traveling' in a reverse direction to the draft of the heater proper, entering the flue pipe in the rear of the heater, and finally distributingl the pre-heated air over the lire with a tempera-ture sufficientto ignite lthe maximum amount of gas possible.

The principal object of iny invention 5oy therefore, is an air pre-heater for heaters using; combustible fuel.

Another object is the savinol of fuel hy a more complete combustion of the gases generated from the fuel. i

In the accompanying drawings illustrat- Serial No. 586,516.

ing thc preferred embodiment of my invent-ion,

Fig. l is a vertical central section showing the pre-heater in the proper position, and adapted'to a pipeless furnace;

Fig. 2 is a cross section taken through the air inlet valve, and indicated by line 2-2 on Fig. l.

Referring to the drawings, l0 indicates a pipeless furnace of the hot air type, in which, il designates the ash pit; 1Q, the lire pot; 13, the space overthe lire pot, and hereinafter called the combustion chamber; 14, the coal door; l5, the radiator, and 1G, the Hue pipe. the rear ofthe furnace, and on the under side of the flue pipe, a. perforation is inade, as indicated at 1'? to admit a close nipple 18, the upper end of which isilittcd with a washer i9 adapted to he compressed against the side of the flue pipe. 16 by the screwing on of the elbow 20 againsta similar washer 2l on the lower or outer side of flue pipe 16, the coupling' 22 having;1 been previously engaged with the said close nipple 18 and firmly clampingl coupling 2l and elhow 20 in an' air tight manner on either side of the flue pipe 1G. yEngaged with the opposite end of coupling 22 is a perpendicular air conduit Q2, the hottoin end of which is adapted to engage with a suitable supporting inemher 23. A sleeve valve 2i having valve openings S25, and 26 is adapted to loosely lit over said conduit 22, the lower end of which rests upon the upper side of the loess .27 formed upon the supportingmember 23. Similar valve openings 2S and 29 are located directly opposite in the conduit 22, and so designed that a, ninety degree turn of the valve sleeve 21twill ent-irely close the openings 2S, and 29 in the Conduit 22. Atninety degrees to the conduit 22, and located on the lower inside of liuc pipe 16, is another conduit 3G, the rear end of which is cngaged with the other ninety degree face of the elbow 20. The front end of conduit 30 is adapted to receive an air tight plug 3l, and he supported by a perpendicular pin 32 securely driven int-o the lower side of conduit 30, and. resting upon the bottoni of the heater radiator 33. An opening 34 is provided at the forward end of said conduit 30 and is adapted to provide for an exit at right angles to conduit on either side and so positioned that the flow of air through At a point a short distance yto til) it willbe in a plane parallel to the Hoor of said heater radiator, as shown at` 33.

In operation', gasesl formin the combustion chamber 13, and if suliicient oxygen is present ignite, but before this ignition takes place, the air containing this oxygen must be raised to a certain temperature. It is a well known fact that when air is heated or its temperature raised, it expands and weighs less per cubic foot than cold air. It is commonly accepted that hot air rises of its own accord, but in reality the reverse is true as the cold air having a heavier specific gravity presses down and crowds the hot air up. Vith this principle it will readily be seen that as the air over the fire in, chamber 13 becomes heated it is elevated to the top of the dome of the heater radiator. The ra diator consists of an annular chamber connected to the central dome 35 by means of an opening 36 located at the front .of the heater. Cold air enters the valve openings 28, and 29, passes up through the conduit 22 and thence through the conduit 30 out through the ope-ning 34:, around each side of the radiator, but always seeking the lowest level, and finally reaching the combustion chamber 13. In the meantime this iii-flow of cold air has elevated the hot air to the highest level of the radiator, and by the time the cold air arrives over the fire it has been heated to a sufficient temperature for the oxygen in it to ignite with gases formed in the combustion chamber. Regulation of the amount ofair coming in is controlled by the sleeve valve 24. In order for this cycle to take place it is absolutely essential that the cold air inlet be at a point below the grate of the heater. Another important result is obtained with this apparatus in the added amount of heat radiated from the top of the heater radiator due to the hot air being crowded up against this surface. This principle applies inV the same way to steam heaters, and in fact to any heater wherein combustion of air must be utilized, and as heat will not pass through a vacuum, air l bottom of the-lirebox and an exit end terminating adjacent the top of the hemispherical dome whereby oxygen is dra-wn from the exit end of said oxygen supply means into the hemispherical dome inra direction opposite to the direction of the normal draft of the consumed gases from the firebox.

An improved means for furnishing pre.- heated oxygen containing fluid to the combustion chamber of a furnace comprising, in combination with a furnace, ay lirebox, a hemispherical dome mounted on and above the lirebox and provided with an exhaust passage at the top thereof, an exhaust flue surrounding the upper portion of the hemispherical dome and having an exit end leading therefrom, a conduit comprising a right angled member having its entrance end located at a point below the bottom of the lirebox of a furnace and its exit end terminating at a point adjacent the exhaust passage from the hemispherical dome and in the bot tom of the exhaust flue whereby oxygen bearing fluid is led from the outer air to the portion of the exhaust flue surrounding the hemispherical dome and there preheated and is then moved in a direction opposite to the direction of flow of the consumed gases from the lire in the irebox. v

In witness whereof, I hereunto subscribe my name this 5th day of Sept., 1922.

HERMAN E. BEEDE.

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