US2053434A - Furnace header - Google Patents

Description

Patented Sept. 8, 1936 PATENT OFFICE FURNACE HEADER George P. Jackson, Flusling, N. Y., assignor to Combustion Engineering Company, Inc., New

York, N. Y.

Application October 9, 1934, Serial No. '747,514

5 Claims.

I My invention pertains primarily to headers and is particularly applicable to headers of water cooled tubes for the Walls of boiler furnaces.

I It has become common practice to provide the inner surfaces of furnaces such as those used with boilers or like structures with rows of vertical Water tubes 'the lower ends of which connect to headers for supplying Water to such tubes. It has been found necessary to pro-vide as many hand-bole openings in the lower header as there are vertical generating tubes. Except for troubles due to action of hot gases on hand-hole closures, the most convenient and economical arrangement of such tubes and lower headers is to place. such headers alongvthe inner faces of the wall or walls of .the furnaces, but the requirement of hand-holes has resulted in placing the headers entirely away from hot gases either by extending the wall' tubes downward to throw the lower headers entirely out of the zone of hot gases or by bending the lower ends of the tubes to cause them to run through the outer refractory Wall of the furnace. The latter arrangement is usually the. most economical and. almost all the recent installations have placed the headers for the lower tubes on the outside of the furnace walls altho such location of the headers involves bending of the wall tubes outwardly through the refractory Section of the wall as' well as a special and costly seal against air leaks where the tubes pass through the refractory section and insulation of the exposed tubes and headers to prevent loss of heat.

v It is an object of my invention to provide an arrangement having the headers on the inside of the refractory Wall section and which shall be free from the above mentioned hand-hole diiculties.

In .carrying out my invention, the wall tubes are run vertically into the upper sides of the headers without bends and the hand-holes and closures therefor are located on the lower surfaces of the headers while such closures are protected by suitable means from the furnace gases so that distortion and/or freezing of the parts as well as spalling of such removable bricks asmay be used is avolded.

The novel features of my invention are pointed out in the appended claims. The invention itself, however, together with its objects and advantages, Will best be understood from the following description of a specific form thereof illustrated in the accompanying drawing and selected as an exemplification of the invention from a number of possible embodiments thereof. In thedrawing,

Fig. 1 is a sectional elevation of a portion of a furnace chamber having water cooled wall tubes and header arrangement in accordance with my invention.

Fig. 2 is a fragmentary View on an enlarged 5 scale of a portion of Fig. 1.

In the arrangement illustrated, a refractory section of a wall of the furnace chamber IU is 'shown at IZ. Furnace IO is assumed to be associated With a steam boiler but the invention is not limited to boiler furnaces. Along the inner face of Wall section |2 is a row of vertical water cooled tubes one of which appears at !4. The lower end of each of tubes 14 is rolled into the upper face of a header !6, the top connections for 15 tubes M being immaterial to the invention and not being illustrated, Header !6 lieson the inside of the refractory wall section !2 in such position that it is subject to hot furnace gases except where some provision may be made to protect it from such gases. i

In the lower face of header IS, handhole openings !8 are provided, one for each tube !4 to permit access to the lower ends of such tubes. During operation, the openings !8 must be closed and closure means 20 are shown for this purpose. `A novel type of hand-hole closure means isillustrated and described in detail hereinbelcw, but I do not limit myself to such type of closure. In order to: protect, at least in part, the closure means 20 from the hot gases, the refractory of wall 20 is built out into a shoulder 22 below header IS. However, the fixed shoulder proper cannot be brought close to the bottom of header IS without cutting ofi access to the closure means gr 20. I therefore build up the shoulder 22 as close as practicable to the bottom of header [6 by removable bricks 24, thereby providing ready access to closure means 20 and at the same time shielding such means considerably from the hot furnace gases. However, the ordinary hand-hole closure projects outwardly from the header and so does not permit the bricks to be brought very close to the lower face of the header and, even if the closure means should not project outwardly from the face of the header, it is difiicult to arrange the bricks so close to the header face as to prevent serious trouble from the action of the gases on both the closure means and the top face of the bricks 24 unless special means are pro- 5 vided to seal the space between the header and such bricks on the furnace side of the closure means or near the outer edge of the bricks. It should be explained that while refractory brick such as shown at 24 are quite capable of Withstanding high temperatures when heated on one face only, they deteriorate due to spalling caused by unequal expansion and contraction when heated on two adjacent faces.

In the embodiment of the invention illustrated in the drawing, the space 26 between the header !6 and the bricks 24 is closed along the furnace end of such space by a metal fin 28 which is fixed to the header !6 at the upper end of such fin by a heat conducting joint, weld metal 38 (Fig. 2) between the fin and the header being illustrated for this purpose. As shown, the fin 28 abuts the Vertical furnace face of bricks 24 so as to form r an efiective seal therewith to substantially exclude furnace gases from space 26. Moreover, a fin permits relative movement between header IE and bricks 24 without impairment of its sealing action. such movement necessarly occurs due to changes in temperature of tubes [4. However, I do not limit myself in all cases to a fin for such sealing purpose.

The shorter the space 28' in the vertical direction, the thinner the fin 28. may be without danger of its burning off, because a narrower fin need conductless heat to the header IE. I have accordingly, devised and illustrated a novel handhole closure illustrated in the drawing which has the valuable characteristic of permitting a Very considerable reduction in the height of space 26.

As shown and particularly illustrated in Fig. 2, my handhole closure has an internal cup shaped closure plate 32 adapted'toseat against the inner face of the header Hi to close the opening |8 in the usual manner. Usually a gasket 34 will be employed between the plate 32 and the header IS altho the gask-et is no part of the present invention. Plate 32 has a bolt 36 riveted on in the usual manner, bolt 36, however, being much shorter than usual so as not to project beyond the'opening !8. The yok-e member 38 also is unusual and arranged so as not to project beyond the opening !8. In order to permit the yoke 38 to sustain a tension in the bolt 36 to hold plate 32 in place, the outer edge of the opening !8 is beveled as indicated at 48 and the yoke 38 has a slope corresponding to the bevel of the header at point 40 so that yoke 38 seats against the header around the opening [8. A nut 42 is employed on the bolt 36 in the usual manner in order to clamp the plate 32 and the yoke 38 together to hold the plate 32 firmly in place. It will be seen that the handhole closure in accordance with my invention can be designed to lie entirely within the spac-e outlined by the header 16, but I do not limit myself to this in all cases.

While the'hand-hole closure illustrated in the drawing is particularly well adapted for use with headers subject to hot gases, other applications may be made of it and I do not limit myself to any particular header location of arrangement so far as my claims to the closure means proper are concerned.

In Fig. 1, means are shown for supplying headers [6 with water, such means including a number of pipes entering the side of the header, one such pipe being shown at 44. However, I do not limit myself to any particular arrangement for supplying header |6 with water. In Fig. 1, moreoVer, are illustrated several tubes 46, 46 arranged so as to form a screen across the furnace chamber 10 at a level somewhat above that of header Hi so that the portion 48 of chamber o lying below the tubes 46 may be considered as an ash pit. It Will be understood, therefore, that the phrase "furnace chamber" as used in the appended claims covers an ash pit portion of a furnace as well as the combustion zone proper.

What I claim is:

I. The combination of a furnace chamber, a header within said chamber arranged. along the wall thereof and having a hand-bole in its lower face, clcsure means for said hole, refractory directly below and spaced from said header, and a fin fixed to said header in heat conducting rela.- tion thereto on the furnace side of said hole and extending downwardly to overlap said refractory and to substantially exclude furnace gases from the space between said header and refractory.

2. The combination as set. forth in claim 1 and in which the refractory facing the hand-hole is readily removable to permit access to such hole.

3. The combination of a furnace chamber, a header within said chamber having a hand-hola in its lower face, means for closing said hole and lying substantially within the outer surface of said header, removable refractory immediately below and spaced from said header and means for substantially excluding furnace gases from the space between said reiractory and header.

4. The combination as set forth in claim 3 and in which the gas excluding means includes a metal fin fixed to said header in heat conducting relation thereto.

5. The combination of a furnace chamber, a header within said chamber arranged along the wall thereof and having a hand-hole` in its lower face, closure means for said hole, ref'actory below said header and forming a shoulder spaced from the latter, and means in heat conducting relation with said header for scaling the space between the latter and said shoulder to prevent contact of hot gases With the upper face of said shoulder and the opposed lower face of said header, the refractory directly below said header being readily removable for providing access to said hand-hale.

GEORGE P. JACKSON

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