US3792689A

US3792689A - Reformer heater

Info

Publication number: US3792689A
Application number: US00305979A
Authority: US
Inventors: A Cross
Original assignee: Lummus Co
Current assignee: CB&I Technology Inc
Priority date: 1972-11-13
Filing date: 1972-11-13
Publication date: 1974-02-19
Anticipated expiration: 1991-02-19

Abstract

A wall bounding in part a heating chamber of a furnace has an opening. A bank of tubes extends in cantilevered relationship through the chamber; the free ends of these tubes are subject to vertical and horizontal displacement when the tubes expand and contract due to heating. A connecting element connects the free ends of the tubes and moves with them. A portion of the connecting element extends through the opening of the wall and is engaged from above by a constant-support hanger. The opening is closed by a cover which is carried on the connecting element portion and movable with the same. The connecting element portion can move vertically and horizontally in the opening.

Description

United States Patent [191 Cross [451 Feb. 19,1974

[ REFORMER HEATER Alan N. Cross, Little Neck, N.Y.

] Assignee: The Lummus Company, Bloomfield,

22 Filed: Nov. 13,1972

21 Appl.No.:305,979

[75] Inventor:

Primary Examiner-Kenneth W. Sprague Attorney, Agent, or Firm-Richard J. Holton et al.

[57] ABSTRACT A wall bounding in part a heating chamber of a furnace has an opening. A bank of tubes extends in cantilevered relationship through the chamber; the free ends of these tubes are subject to vertical and horizon tal displacement when the tubes expand and contract due to heating. A connecting element connects the free ends of the tubes and moves with them. A portion of the connecting element extends through the opening of the wall and is engaged from above by a constant-support hanger. The opening is closed by a cover which is carried on the connecting element portion and movable with the same. The connecting element portion can move vertically and horizontally in the opening.

6 Claims, 3 Drawing Figures PATENTED 3,792,689

SHEET L [If g REFORMER HEATER The present invention relates to a furnace construction, in general, and in particular, to a construction in which the free ends of heat-exchange tubes are mounted for displacement under the influence of thermal expansion and contraction of the tubes.

When tubes extend through a heating chamber of a furnace, they expand and contract as they are subjected to greater or lesser amounts of heat, respectively. If the tubes are fixedly mounted, such thermal displacements may lead, at best, to damage to the tube mounts; more dangerously, these movements may lead to rupture of the tubes themselves and to the loss of the heat-exchange fluid passing through the tubes.

The problem is not new and has been recognized before. For various reasons, the attempts to overcome it in the prior art have, however, been either unsuccessful or unsatisfactory.

It is a general object of this invention to overcome the aforementioned problem and to avoid the disadvantages found in the prior art.

More particularly, it is an object of the invention to provide an improved furnace construction which meets this general object.

Still more specifically, it is an object of the invention to provide, in a furnace construction, an improved mounting arrangement for tubes whose free ends are subject to movements due to thermal expansion and contraction of the tubes.

In keeping with this and other objects, which will become apparent hereafter, the invention provides, in a furnace having a heating chamber, a wall which is provided with an opening. A bank of cantilevered tubes extends through the chamber and the tubes have free ends adjacent the opening. Connecting means connects the free ends and is movable with them. A portion of the connecting means extends through the opening and is journalled by journaling means so that it can perform at least vertical movements in the opening.

A single exemplary embodiment of the invention is illustrated in the appended drawing; this embodiment should be understood as being purely illustrative and is not to be considered limiting of the invention.

FIG. 1 is a fragmentary vertical section, showing a detail of the illustrated embodiment;

FIG. 2 is a top-plan view of FIG. 1; and

FIG. 3 is a somewhat diagrammatic side-elevational view of a portion of a furnace incorporating the embodiment of FIGS. 1 and 2.

In all these figures, reference numeral 1 designates a heating chamber of a furnace. This could be any type of furnace, such as a reforming furnace, a liquid or fluid heater having a convection section, or the like.

In the illustrated embodiment the chamber 1 is bounded in part (see FIG. 3) by an upright wall 2 which is provided with an opening 3. A bank of tubes 4 extends in cantilevered horizontal relationship through the chamber 1, as shown in FIG. 3. Their free ends are connected by a connecting element 5 which is illustrated most clearly in FIG. 1. The term cantilevered as employed relative to the tubes 4 refers to the fact that they are mounted rigidly only in the region of one end (the right end in FIG. 3), but no mounting is shown), whereas the remainder of each tube 4 is supported only by the spring hangers 9 shown in FIG. 3. Thus, when the tubes 4 expand or contract as a result of varying thermal effects upon them in the chamber 1, they are free to undergo vertical and/or horizontal dis placement (whichever the case may be) with their cantilevered portions, including, of course, their free ends.

Such displacement causes concomitant movement of the element 5, and of the portion 6 of this element which extends through the opening 3 to the outer side of wall 2. At this outer side the portion 6 is engaged and journalled by a constant-support hanging arrangement 10, i.e., an arrangement which will support the element 5 at whatever elevation the portion 6 thereof may have in the opening 3. The free ends of'the tubes 4, the element 5, and the portion 6 thereof, can move vertically as indicated by the arrow 8 of FIG. 1, for instance, by 10 inches.

The dimension of opening 3 in horizontal direction (i.e., normal to arrow 8) may be so selected that portion 6 can also have some freedom of movement in this direction, for instance, about 4 inches. The dimensions mentioned herein are, of course, not to be considered limiting.

On the outer side of wall 1, the portion 6 carries a cover 7 which surrounds it and is movable with it. Cover 7 overlies the opening 3 in contact with the outer side of the wall, on which it can slide as portion 6 moves, thus closing the opening 3 even when maximum displacement of portion 6 takes place.

With the present invention it is thus possible to mount the relatively long, thin tubes 4, so that they can perform movement dictated by thermal expansion and contraction. Moreover, such movement is now possible between two sections of a furnace (two banks of tubes), or between a bank of tubes and a transfer line, without any damage or danger due to overstressing.

What is claimed is:

1. In a furnace having a heating chamber, a combination comprising a wall having an opening; I

a bank of cantilevered tubes extending through said heating chamber and free ends adjacent said opening, said tubes being subject to thermal expansion upon heating with a resultant displacement of said free ends in at least vertical direction;

connecting means connecting said free ends of said tubes and being subject to displacement with said free ends; and

journalling means journalling a portion of said connecting means in said opening of said wall with freedom of displacement in at least vertical direc' tion.

2. A combination as defined in claim 1, wherein said wall at least in part bounds said heating chamber.

3. A combination as defined in claim 1, said connecting means comprising a connecting element which en gages the respective free ends of said tubes; and wherein said wall comprises a cover element surrounding said portion and overlying and covering said opening at one side of said wall, said cover element having freedom to participate in the displacement of said portion of said connecting element.

4. A combination as defined in claim 3, wherein said portion extends through said opening from one side of said wall at which said tubes are located, to an other side; and wherein said journalling means engages said portion at said other side.

5. A combination as defined in claim 4, wherein said journalling means comprises constant-support hanger means suspending said portion from above.

6. A combination as defined in claim 5, wherein said portion is received in said opening with freedom of horizontal displacement also.

Claims

1. In a furnace having a heating chamber, a combination comprising a wall having an opening; a bank of cantilevered tubes extending through said heating chamber and free ends adjacent said opening, said tubes being subject to thermal expansion upon heating with a resultant displacement of said free ends in at least vertical direction; connecting means connecting said free ends of said tubes and being subject to displacement with said free ends; and journalling means journalling a portion of said connecting means in said opening of said wall with freedom of displacement in at least vertical direction.

3. A combination as defined in claim 1, said connecting means comprising a connecting element which engages the respective free ends of said tubes; and wherein said wall comprises a cover element surrounding said portion and overlying and covering said opening at one side of said wall, said cover element having freedom to participate in the displacement of said portion of said connecting element.