US2212697A - Regenerative furnace - Google Patents

Description

reseau aug; av, ieee angst Ny orifice c l REGENERATIVE FRNACE' `-Peer D. Nielsen, Lorain, Ohio, assigner to National Tube Company, al corporation. of New 'Jersey This invention relates to regenerative melting furnaces, and more particularly to the checker chambers thereof which areemployed for preheating the air or gas used for combustion purbe" fired with gas, oil

poses, whether the furnace or tar. y

, In conventional designs, the checker chamber is filled from end-to-end withN brick checkerwork,

through the openings of which waste gases and m air or gas alternately pass during the periods between furnace reversals'. Suitable spaces are provided above and below the checkerwork to allow for distribution of gas and air above and below the openings passing through the checkerwork;

15,to facilitate blowing out dust which collects in the openings in the vcheckerwork; for periodic replacement of the top courses `of brick; and for the accumulation of dust in iiues below the checkers.

When the furnaceis operating, waste gases enter the checker chamber through 'an inlet and.' after giving up a portion of their heat to the checkerwork, pass out oi the Vchamber tothe furnace stack through an outlet. Likewise,

when the furnace is reversed, air or gas enters the chamber through the outlet and, being preheated in traveling through the checkerwork, passes to the furnace through the inlet.

As previously stated, in the conventional design of hc hecker chamber the checkerwork is continuous over the length of the chamber and therefore abuts against the bulkhead at the cold end of the chamber, or the end remote` from the furnace.

0n account of the use of this type of construction it is necessary. in order to get at the checkerwork for thorough cleaning and removal of the dust which accumulates in the fiues belowv the checkers, to remove all checkerwork for a distance of several feet back from the bulkhead on the cold end. This operation, usually carried on whenever the furnace is rebuilt, involves the removal and relaying of several thousand bricks simply to` gain access to the iiues and provide 45 room for cleaning that part of the checkerwork not removed from the chamber.

A further disadvantage of this conventional type of construction is that lt is not possible to reach the corners of the checkerwork, adjacent to the bulkhead on the cold end of the chamber, for cleaning by Vmeans of air or water while the furnace is operating. These corners are inaccessible because of the fact that a small opening only can be made in the bulkhead. when the 2 claims. (c1. 26a- 1.5)

furnace is' hot, for insertion of cleaning equipment.

It is amongsfthe objects of the present. invention to provide a regenerative melting furnacewhich is cheap and easyto recondition or rebuild.

Another object is to provide a checker chamber of the type described which is more ecient in operation than the checker chambers of the prior art.

TheA invention, then, comprises the features o hereinafterl fully described and as particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail the certain illustrative embodiment of the invention, this being indicativeof but one of 15 a number of ways in which the principles ofthe invention may be employed.

In said drawings: v

Figure l is aplan of the checker chamber of the invention; 20 Figure 2 is a, sectional elevation on the line II-II of Figure 1; and

Figurei is a sectional view on the line III-III of Figure 2.`

Referring more particularly to the drawings, 25 the numeral'2 designates the floor line above and below which the checker chamber oflthe invention is to be built.

A'I'he checker chamber comprises a pair of spaced .vertical side walls 3 which support a roof 30 l. At one end of the walls 3 and the roof 4, the checker chamber embodies a removable bulkhead 5 which provides ready access to the interior of the chamber for the purposes of rebuilding or inserting cleaning tools, as will appear '35 more fully hereinafter.

The checker chamber of the present invention provides, adjacent the end having `the removable bulkhead 5 and spaced several feet therefrom, a division wall 'i which extends the full width of 40 the chamber but is spaced from the roof 4. .Between the division Wall 'i and the opposite en d of the checker chamber is provided a space within which there is the usual assembly of checker- Work 8. 45

The arch over that portion of the flue extend- Y ing Within the limits of the checker' chamber is so constructed that approximately one-half, ad-

vjacent tothe bulkhead 5, provides a permanent platform i0, level on top, for use in removing 50 dust from the fiues under the checkerwork, and the remainder built as a removable arch i2 which provides, by its removal during rebuilding, an inexpensive means of entry to the iiues under the checkerwork. i 55 Beneath the end of the furnace having the removable bulkhead 5 isa conduit I4 which comprises the air or gas inlet and waste gas outlet of the checker chamber. This conduit I4 (air or gas inlet and waste gas outlet of the checker chamber) communicates with a space I5 which is immediately beneath the checkerwork 8 of the checker chamber and, accordingly, the space 6 which is immediately above the checkerwork. The conduitIS, which lcomprises the heated gas or air inlet and the waste gas outlet of the furnaceyis disposed above the level of the iioor line 2.

According to the foregoing, it will be noted that the cold or stack end of the checker chamber is that end which is beneath the removable bulkhead 5 and provided with the conduit I4 (air or gas inlet and waste gas outlet).

The numerals 2|, 22 and 23 respectively designate the slag pockets, downtakes, and furnace interior. interior through the downtakes to the vslag pockets and thence through the conduit, or connecting flue, I6 to the regenerator chambers. Similarly combustion media preheated in the regenerator chambers to a high temperature pass from the regenerators through the conduit, or

connecting flue, I6 to the slag pockets 2l and through the uptakes 22 to the furnace interior 23.

Among the advantages provided by the invention are the following:

(1) During the' rebuilding of the furnace and reconditioning of the checker chambers, no checker-bricks are removed except those, usually in the top courses, which have been damaged by temperature or-the fiuxing action of waste gases or both.

(2) Vertical openings can be blown down with compressed air as at present.

(3) -Horizontal openings, if present, can be blown out by constructing the division wall' 1 with an opening opposite each horizontal pas-- Sage through the checkerwork, these openings to be closed with a brick plug during normal operation or left open, if desired, to allow clean.- ing during the operating campaign.

(4) Dust which accumulates in the ues under the checkerwork, during operating' periods, or which is blown down from the checkers during the cleaning operation, can be removed from the furnace by taking out the bulkhead 5 at the "cold end of the checker chamber and removing the removable arch I2, thus providing ready access to the flues and ample room for throwing dust from flues to the permanent platform I Il and from the latter to the`outside oor level through the opening afforded by the removable bulkhead 5.

(5) The provision of the permanent platform I0 eliminates the expense incident to the erec-l tion of atemporary scaffold in the checker chamber as required with conventional designs.

(6) The improved construction makes periodic cleaning of checkerwork; during the time the furnace is operating, a more thorough and effective operation as the checkerwork is more accessible. With the checkerwork removed some dis- -tance from the removable bulkhead 5, the cleaning distribution of both waste gases and air.

through the checkerwork of chamberswhich have been built with excessive length. Where exces- Waste gases escape from the furnace(v sive length is present, the waste gases entering the checker chamber pass very largely down nace, the amount of waste gas passing through the checkers diminishing in volume toward the hot end (furnace end) and verylittle going down in that part adjacent to the bridge wall, designated at 20.

The reason for this is believed to be that the waste -gas flue, connected to the "cold end of the chamber 6, exerts the greatest influence for removalof Waste gases at the cold end, this inuence diminishing toward the hot end until entirely dissipated and there exists no influence to draw gases through the checkers at the ex# treme orhot end .in cases where the checker chamber is too long. The aspiratingeifect of the flow of gas over the bridge wall 20, in con. junction with its velocity, also works against passage of waste gas through checkers adjacent -to the bridge wall as suicient differential pressure i doesnot exist between the top and bottom of the checkerwork to make the gases turn and flow downward in the area near the bridge wall 20.

Likewise, after the furnace is reversed'and the checker chamber used to'preheat the air entering the "cold end, the influence to draw air through the checkers is greatest at the hot" or furnace end and least at the cold or stack end. Therefore, in a chamber of excessive length, most of the hot waste gases pass down the checkerwork adjacent to the so-called cold end and most of 'the air up through the checkers at the so-called hot end, thus eliminating the possibility of maximum heat transfer from waste gas to air through the medium of the checkerwork.

end of the checker chamber, the heat loss is Athe greatest for the reason that four surfaces of the chamber are exposed on the cold end to room temperature. of the checkerwork from the bulkhead 5 on the cold end of the furnace, the heat transfer between the checkerwork 8 and the atmosphere outside of the checkerwork is-reduced and the efflciency of the checkerwork as a heat transfer medium is improved.A v

Another advantage of the shortened checkerwork is that a greater differential pressure will be built up between the inlet and outlet of the checkers and therefore an improved distribution of gas or air will be effected.

While I have shown and described one specific embodiment of the present invention, it will be. seen that I do not wish to be limited exactly thereto, since various modifications maybe made without departing from the scope of the invention, as defined by the following claims.

I claim: l. In a regenerative furnace, a regenerative chamber having a fluid conduit communicating therewith, checkerwork in` said chamber, a removable bulkhead adjacent the end of said re- Therefore, by separating the end= -sion wall being spaced from the generative chamber which is remote from the furnace, said checkerwork being spaced from said removable bulkhead whereby there is formed a chamber between said lremovable bulkhead and the adjacent end of said checkerwork, a removable arch in the bottom of said chamber, and a division wall between said removable arch and the adjacent end of said checkerwork, said diviroof of said furnace. v

2. In a. regenerative furnace, a regenerative chamber having a fluid conduit extending'under neath the same, checkerwork in vsaid chamber and in communication with said uid conduit,

a removable bulkhead adjacent the end of said regenerative `chamber which is remote from the furnace, said checkerwork being spaced from :said removable bulkhead whereby there is formed a chamber between said removable bulkhead and the adjacentend of said checkerwork, the bottom of said chamber being closed from said fluid conduit and provided with a removable arch, and

a division wall between saidv removable arch and the adjacent end of said checkerwork, said division wall being'v spaced from the roof of said furnace.

PEER D. NIELSEN.

Images