US1361351A - Air-heater - Google Patents

Description

AIR HEATER.

W. SPOELSTRA.

APPLICATIQN FILED SEPT B, 1920. 1,361,351

Mam

W. SPOELSTRA.

AIR HEATER.

APPLICATION FILED SEPT, 8. I920.

Patented Dec. 7, 1920.

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AIR HEATER.

APPHCATION FILED SEPT-8. 1920.

Patented Dec. 7,1920.

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AIR HEATER.

APPLICATION FILED SEPT. 8, I920.

Patented Dec. 7, 1920.

4 SHEETS-SHEET 4.

WATZE SPOELSTRA, OF SAN J'OSE,'CAL1FORNIA.

AIR-HEATER.

Specification of Letters Patent. Patented Dec. 7, 1920.

Application filed September 8, 1920. Serial No. 408,998.

for use in connection with drying appa-- ratus for supplying heated air thereto.

According to the invention, a combustion chamber or furnace is utilized in which the fuel is burned, this chamber being completely encircled by an annular air inlet passage which communicates with a main heating chamber into which the combustion chamber opens. Both the annular air passage or chamber and the adjacent outer portion of the main heatin chamber are fitted with tubes, the rear en s of the air chamber tubes and the front ends of the heating chamber tubes being fitted in openings in a change header plate which conjointly forms the rear wall of the air chamber and the front wall of the main heating chamber. The air chamber is open at its front for ingress of air, and the tubes therein project beyond said chamber and open into an an nular chamber which encircles the front end of the combustion chamber and which communicates with a stack so as to produce the required draft. The rear ends of the tubes in the main heating chamber open into an air collecting chamber from which the heated air passes through an exhauster and is piped to the drier or other point of use. The air collecting chamber is preferably equipped with an auxiliary heating chamber which is located interiorly thereof and is provided with its own set of air inlet pipes;

the air heated in the auxiliary chamber discharging into the collecting chamber.

Owing to the above described construction and arrangement of parts, the air drawn in through the open-ended air chamber will circulate freely around the tubes therein and which convey the flue gases or gases of combustion from the main heating chamber and discharge theminto the annular chamber at the front of the combustion chamber, whence they pass to the stack. On reaching the rear end of the air chamber, the air enters the tubes or Hues disposed in the main heating chamber and then flows into the collecting chamber; the disposition of the tubes or flues in the main heating cham her being such as to enable the flue gases to circulate freely around and act directly on them, so that the air will be heated to the proper degree by the time it enters the collecting chamber, While the flue gases will have given up a part of their heat before entering their exit tubes or flues. The currents of air and gas travel horizontally in opposite directions through their respective flues; the air passing through the air chamber entirely surrounding the gas flues or tubes therein, While the flue gases in the main heating chamber entirely surround the air flues.

The auxiliary heating chamber has its front wall formed by the rear wall of the main heating chamber, so that the air supplied to the former chamber through the auxiliary inlet tubes or flues will be rapidly heated. These auxiliary flues may be equipped with suitable regulating devices to control the passage of the air therethrough and, hence, the amount of air re ceived in the collecting chamber, thereby providing for semi-permanent regulation of the heater to the point of greatest efliciency.

Other improvements and advantages will become apparent in the course of the following description.

An embodiment of the invention is illus trated in the accompanying drawings, in'

which:'

Figure 1 is a central vertical section of the improved heater.

the chamber, so that the flue gases or gases of combustion will be caused to pass rearward through the chamber into'the subsequently-described main heating chamber 3. The combustion-chamber is provided-with suitable heating means 111 shown diagrammatically, in Fig. 1, as in the form of an vspaced acomparatively slight distance behind a second annular chamber 5, which encircles the extreme front portion of the combustion chamber and is closed by front and . back plates 6 and 7 the outer or annular .wall of this chamber 5 having a discharge opening 8 from which a flue 9 leads to the stack (not shown) The rear end-of the air chamber 4 is closed by a plate 10, hereinafter termed the change header plate, which conjointly forms the rear wall of that chamber, and the front- .wall of the previously-mentioned main heating chamber 8, which is likewise of cylindrical form and has a diameter equal to that of the outer wall of chamber 4,in other words, the combined diameters of the combustio'n chamber and the air chamber proper. The portion of the change header plate 10 which is immediately behind the combustion chamber 1, is left open.

The back plate 7 of the discharge chamber 5 is formed with a circular series of openings 11 which exactly aline with a coaxial series of openings 12 formed in the change header plate 10, these openings having fitted therein the corresponding ends of a series of horizontal tubes or lines 13 serving to conveythe flue gases from the main heating chamber 3 through the air chamber 4 into the above-mentioned discharge chamber 5; the 'said flues being spaced substantially equidi'stantly of the'walls of the air chamher, so that the in-coming air can circulate freely around and along them during its progress through the air chamber and be heated in that way. The header plate 10 has formed in it, in addition to the gas flue inlets 12, a plurality of circular series or rows of openings 14, all of which additional rows are concentric with one another and with the intermediate row 12. These openings 14, the two inner rows of which have a slightly smaller diameter than the remaining rows, receive the front ends of rows of tubes or fiues 15, whose rear ends lit in corresponding openings 16 formed in the rear plate 17 of the main heating chamber 3; both ends of the flues being left open, so that the air in the chamber 4 may be drawn therethrough and discharged into the collecting chamber 18 which is located immediately behind the chamber 3 and has the same-diameter as that chamber. The fines 15: are spaced sufficiently far apart from one anotheriand from'the wall of chamber 3 to perrnit'them to be entirely surrounded by thefiile gases in chamber 3wh1ch are thereaused tojgive Euip' a'portion of their heat,

with the result that the air in passing through the fiues is heated to the required temperature.

The central portion of the main heating chamber contains no flues, as will be understood from Figs. 1, 4 and 5; and the corre sponding portion of the end header plate 17 which conjointly forms the rear wall of said chamber and thefront wall of the collecting chamber 18 is removed, the opening thus produced being covered by a detachable plate 19. The latter forms the front wall of an auxiliary heating chamber 20, which is located within the chamber 18 and is supplied with air through an individual set of short inlet lines 21, which extend at their front ends through openings 22 in the rear plate 23 of chamber 20 and at their rear ends through openings 24 in the rear plate or end header plate 25 of the collecting chamber 18. The flue openings 22 are disposed comparatively close to the edge of plate 23, which latter is further provided with a central discharge opening 26 for the escape of the heated air into the collecting chamber, from which it passes through an opening 27 in the end header plate or rear plate 25 into an exhauster (not shown) which supplies it to its point of use.

The plates which form the front and rear walls of the several chambers may be mad in sections for convenience of construction, and for replacement of tubes, as will be understood from Figs. 2 to 5 and 7 the air passage or chamber 4 may be subdivided into a number of separate passages, if desired; and various other minor changes or additions may beresorted to within the scope of the invention.

Means are provided in connection with the auxiliary inlet fines or tubes 21 for controlling the air flow thercthrough, said means being here shown as in the form of caps 28 (indicated in dotted lines in Fig. 1) which may be removably attached to any or all of these tubes. The tubes left opened or uncapped bring in air of lower temperature for admixture in the collecting chamber with the air supplied thereto through the main lines 15, so that the temperature of the air withdrawn through the opening 27 is the resultant of such admixture. Hence by Varying thelnumber of auxiliary tubes left open, the temperature at which the air is piped off from the header may be corresp'ondingly modified within certain limits, thereby providing for a regulation to the point of greatest efficiency. i

I claim as my invention 1. An air heater, comprising in combination, a combustion chamber; an annular air inlet passage encircling the same; a heating chamber located immediately behindthe combustion chamber and in free communication""therewith to permit the gases of combustion to pass from the combustion chamber to the heating chamber; a series of fines arranged in the air passage and opening at their inlet ends into the heating chamber to convey the heated gases from said heating chamber through said passage and thereby heat the incoming air flowing through the passage; a series of air flues arranged in said heating chamber and around which the heated gases in the heating chamber freely circulate prior to their entry into the gas flues, said air flues opening at their inlet ends into said air passage; and an air collecting chamber behind said heating chamber and intowhich the outlet ends of the air flues open. 7

2. An air heater, comprising in combination, a combustion chamber; an annular air inlet passage encircling the same; a heating chamber located immediately behind the combustion chamber and in freecommunication therewith to permit the gases of combustion to pass from the combustion chamber to the heating chamber, a series of fines arranged in the air passage and opening at their inlet ends into the heating chamber to convey the heated gases from said heating chamber through said passage and thereby heat the incoming air flowing through the passage; a gas discharge chamber encircling the front of the combustion chamber and into which the outlet ends of the gas lines open, said discharge chamber adapted for connection to a stack to create a draft therein; a series of air flues arranged in said heating chamber and around which the heated gases in the heating chamber freely circulate prior to their entry into the gas flues, said air flues opening at their inlet ends into said air passage; and an air c0llecting chamber behind said heating chamber and into which the outlet ends of the air flues open.

3. An air heater, comprising in combination, a combustion chamber; an annular air inlet passage encircling the same; a heating chamber located immediately behind the combustion chamber and in free communication therewith to permit the gases of combustion to pass from the combustion chamber to the heating chamber; a series of lines arranged in the air passage and opening at their inlet ends into the heating chamber to convey the heated gases from said heat:

ing chamber through said passage and thereby heat the incoming air flowing through the passage; a series of air flues arranged in said heating chamber and around which the heated gases in the heating chamber freely circulate prior to their entry into the gas flues, said air flues opening at their inlet ends into said air passage; an air collecting chamber behind the heating chamber and into which the outlet ends of the air flues open; an auxiliary heating chamber located in said air collecting chamber immediately behind the first-named heating chamber to be heated thereby; and means independent of said air lines for supplyin air to the auxiliary chamber to be heatec l therein.

4. An air heater, comprising in combination, a combustion chamber; an annular air inlet passage encircling the same; a main heating chamber in communication with the combustion chamber to receive the heated gases of combustion therefrom; means for conveying said gases from said heating chamber through said air passage to heat the air flowing therethrough; an air collecting chamber; means for conveying the air from said passage through said heating chamber and into said collecting chamber; and an auxiliary heating chamber-located within said collecting chamber and having an air supply means individual thereto.

5. An air heater, comprising, in combination, a combustion chamber; an annular air inlet passage encircling the same; a main heating chamber in communication with the combustion chamber to receive the heated gases of combustion therefrom; means for conveying said gases from said heating chamber through said air passage to heat the air flowing therethrough; an air collecting chamber; means for conveying the air from said passage through said heating chamber and into said collecting chamber; an auxiliary heating chamber located within said collecting chamber; a series of air inlet flues individual to the auxiliary heating chamber for supplying air thereto; and means associated with the individual air inlet flues for controlling the flow of air therethrough.

In testimony whereof I affix my signature.

WATZE SPOELSTRA.

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