US1816466A - Air heater - Google Patents

Description

July 2 8, 1931. J. BOERSTRA 1,816,466

AIR HEATER Filed Jan 13, 1927 3 Sheets-Sheet l JJ A M INVENTOR BY 4 W ATTORNEY:

July 28, 1931.

J. BOERSTRA AIR HEATER Filed Jan. 15, 1927 3 Sheets-Sheet '2 INVENTOR ATTORN EYJ:-

July 28, 1931. J. BOERSTRA 1,316,466

AIR HEATER Filed Jan. 15. 1927 s sheets-sheet a 33 Fig-'7 1 MINVENTOR w TToRNEYs Patented July 28, 1931 UNITED STATES A PATIENT OFFICE JACOBUS BOERSTRA, OF HAARLEM, NETHERLANDS, AS SIGNOR TO THE IB'ABCOCK 8c WILCOX COMPANY, OF BAYONNE, NEW JERSEY, A CORPORATION OF.NEW JERSEY AIR HEATER.

Application filed January 13, 1927, Serial No. 160,816, and in Great Britain May 10,1926.

This invention relates to an air heater that is especially adapted to be heated by hot waste gases from a boiler furnace, and will be understood from the description in con- 5 nection with the accompanying drawings, in which Fig. 1 is a vertical section through an illustrative embodiment of the device; Fig. 2 is a vertical section on an enlarged scale showing one of the details; Fig. 3 is a section along the line 3-3 of Fig. 1; Fig. 4 is a vertical section similar to Fig. 1 showing a modification; Fig. 5 is a vertical section on an enlarged scale showing details of the modification; Fig. 6 is a section along the lines 6-6 15 of Fig. 5; Fig. 7 is a vertical section through another modification and Fig. 8 is a section along the line 88 of Fig. 7.

In the drawings, reference character 1 indicates inclined tubes of a water tube boiler, over which hot gases from the boiler furnace pass, indicated by the arrow. The hot waste gases after passing from the tubes 1 pass into the air heater through inner tubes 2 that are expanded into tube plates 3 and 4. The tubes 2 are surrounded by and are axial with larger tubes 5, so that spaces are left between the inner and outer tubes. The tubes 2 and are preferably made circular in cross section, but may be made of other shapes.

tubes'to rest upon the tube plate 7 with the ends of the tubes extending through holes in this plate. The upper or inlet ends of the the expanded or enlarged portions 8 of adjacent tubes contacting with each other. The

tubes 2 extend beyond the tubes 5 at both ends.

A chamber at the upper ends of the tubes 2 is made up of the tube plate 4 and the walls 9 from which chamber a conduit 10 leads to 4 a stack, or the like. A chamber is also provided below the lower ends of the tubes 5,

' beingmade up of the tube plates3 and 7 and the edge plates 11, from which chamber a conduit 12 leads to the furnace. Air enters so the spaces between the upper'ends of the The outer tubes 5 are provided near their lower ends with beads 6 that enable the tubes 5 and the outside surfaces of the tubes 2and passes downwardly along the annular spaces between the tubes into the lower compartment, and thence through the conduit 12 'to the furnace while hot gases enter the lower ends of the tubes 2and pass from the upper compartment through the conduit 10 tothe stack.

In the modification shown 1n Flgs. 4, 5 and 6 hot gases are passed around the outside of the outer tubes, as well as through the inner ubes, so that the air is heated on both the inner and outer surfaces of the annular streams of air. In this modification, the outer tubes 5' are shown as expanded into an upper tube plate 15, which structure may be, of course,'used with the otherembodinient shown in Fig.1, and the tubes 5 shownin Fig. may be installed as shown in the modification, Fig. 4. In the modification shown in Fig. 4, the gas passage above the last pass of the tubes 1 is enlarged so as'to provide a space 17 along the side of the air heater. A damper 18 is provided to close or'open the passage to the space. When the damper 18 is open a portion of the hot gases pass into the space 17 and thenacross the outside of thetubes 5, being directed across the tubes,

as shown by arrows in Fig. 6, and around the bafiie 19, and thence they pass upwardly through the outlet 10 to the stack after havi'ngjoined the hot gases that pass through the inner tubes 2. Thus the air entering the provided from this gas passage or conduit 16', so that the hot gases 'maypass either through the inner tubes or, around theouter tubes or both. A. damper 21 is provided. for

controlling the passage of the gases to the inner tubes and a damper 22 is provided for controlling the passages of the gases around the outertubes, and a damper 23 is provided so that the gases may be bypassed instead of passing through the air heater. 'An outlet damper24 is provided'for the gases passing around-the tubes and an outlet damper 25 through the gas passage 16. Openings are v is provided for gases passing through the inner tubes.

In the modification shown in Figs. 7 and 8, the inner tubes 26 are expanded into the tube plate 27 at their exit ends and are enlarged at their entrance ends, as. shown at 28, into conical shape and are expanded into the plate 29. The outer tubes 30 extend between tube plates 31 and 32 and the enlarged ends 28 of 19 the inner tubes 26 are made ofsufiicient size to permit the outer tubes 30- to be inserted through the tube plate 29. Air enters through the inlet 33 between the tube plates 27 and 32 and passes through the annular 15 spaces between the tubes into-the chamber between the tube plates 29 and 31-, thence out through the exit 34 to the furnace, while hot gases pass either through the inner tubes or around the outer tubes or both, thence from the exit, conduit 35 tothe stack. The entire arrangement is disposed in a, chamber adjacent the conduit, as plainly shown, access to this chamber from the flue being had by means of the dampers 21, 22, 24 and 2,5,. and air being; admitted, and discharged at 33 and 34 respectively.

I claim:

1. In an air heater, coaxial tubes, means for directing hot gases through one set of 39 said tubes, and means for directing air through the other set, the inner tubes extending beyond the outer tubes and ends thereof being enlarged to at least the outer dimensions of the outer tubes.

35 2. In an air heater, coaxial inner and outer tubes and means whereby hot gases may be passed through the inner tubes, or around the outer tubes, or through the inner tubes and around the outer tubes, at will.

49 3. In an air heater, a set of parallel tubes, a second set of tubes'disposed within those of the first set, an air inlet and outlet con nected respectively to the opposite ends of the tubes in the first set, a hot gas inlet and outlet connected respectively to opposite ends ofthe tubes in the second set, connections from said gas inlet and outlet respectively to the spaces between. the'tubes in. said first set, and valves controlling the flow; through each 50 of said connections.

4. In an air heater, a set ofparallel tubes,

:1 second set of tubes disposed within those of the first set,v an air inlet and, outlet connccted respectively to the opposite ends of the tubes in the first set, a hot gas inlet and outlet connected respectively to opposite ends of the tubes in the secondset, connections from said gas inlet and outlet respectively'to'the spaces between the tubes in said first set, valves controlling the flow through each of said connections, a by-pass connecting said hot gas inlet directly to said hot gas outlet, and a valve controlling said by-pass.

JACOBUS BOERSTRA.

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