US2412568A

US2412568A - Supporting device for return headers

Info

Publication number: US2412568A
Application number: US474790A
Authority: US
Inventors: John E Donahue; Leo W Schrader
Original assignee: Standard Oil Development Co
Current assignee: Standard Oil Development Co
Priority date: 1943-02-05
Filing date: 1943-02-05
Publication date: 1946-12-17
Anticipated expiration: 1963-12-17

Description

Dec. 17, 1946. J. E. DONAHUE ET AL SUPPORTING DEVICE FOR RETURN HEADERS Filed Feb. 5, 1945 Patented Dec. 17, 1946 John E. Donahue and Leo W. Schrader, Elizabeth, N. J., assignors to Standard Oil Development Company, a corporation of Delaware Application February 5, 1943, Serial No. 474,790

3 Claims.

The present invention relates to improvements in furnace construction, and more particularly, to an improved means for supporting and protecting the tube return headers in a furnace.

For illustration, one concrete embodiment of this invention is shown in the sectional perspective view of the accompanying drawing.

It has heretofore been the common practice in constructing tube chambers in furnaces, particularly in the radiant section, to support the sets or banks of tubes and the individual tubes of the sets or banks by tube sheets and intermediate hangers exposed to the effect of heat and gases from the combustion chamber. These tube sheets and hangers must be constructed from special alloys in order to enable them to resist the corroding effect of the gases and the intense heat in the combustion section of the furnace. The use of these heat resistant alloys increases the cost of the heater materially, particularly when it is realized that in a typical installation, usin long horizontal tubes, as many as three intermediate alloy tube supports per pair of tubes are required. in addition to those used at the tube ends to support the header boxes.

By eliminating the use of end alloy tube sheets protecting the header boxes and header-box supports and supporting the tubes, a large part of this cost could be avoided.

Consequently, one of the primary objects of the present invention is the provision of a constructional arrangement in the radiant section of the furnace whereby the tubes are supported at their ends in such a way that the relatively expensive alloy tube sheets are replaced by less expensive refractory and the return headers are shielded from the direct heat of the furnace and are protected from the action of the flue gases.

Another important object of the present invention is to provide an arrangement whereby the tube headers are independently supported behind a wall which protects them from the combustion gases, the supports being so arranged that the tube headers, supports, chamber walls, etc., may move relative to one another under the influence of expansion and contraction forces without strains or stresses leading to deterioration and after reading the following description and claims and after considering the accompanying drawing which is a perspective view of the preferred form of this invention with parts cut away.

The portion of the furnace structure chosen for illustration comprises side Wall I,

end walls

2 and 3, and roof 4 forming the usual combustion section of a furnace. Disposed across the combustion space are roof tubes 5 which terminate in the customary type of return headers 6. These return headers are enclosed in a housing 1 provided with hinged doors 8 which permit ready access to the fittings, header boxes, and the like.

This housing may be attached to the furnace in any suitable manner; for example, it may be attached to the furnace wall by means of supporting I-beams 9 and brackets In. That portion of the housing nearest the furnace interior is constructed of a suitable refractory material forming wall I l which serves to screen the housing, the headers, and other fittings contained therein from the effects of the radiant heat of the furnace and from the combustion gases. This wall is preferablysupported on top of the usual furnace wall 3 and is connected to the roof 4 thru I-beam l2, although it may be simply a continuation of wall 3. The wall II may also be additionally supported by means of steel plate I 3.

Where tubes 5 pierce thru wall t2, the opening between the tubes and the refractory brick may be sealed in any desirable manner as by asbestos rope packing l4.

The tube headers may be supported in the housing by resting them on rollers l5 which are in turn supported by angle-iron supports I6 restingon I-beam IT, or they may be supported in any other desirable manner, such as by U-bolts or J-bolts, so that the headers are free to expand or contract with the tubes in accordance with the change in temperature and conditions in the combustion zone of the furnace.

The present invention, therefore, eliminates the usual alloy tube sheet for supporting the ends of furnace tubes, particularly in the radiant section of the furnace, and provides, instead, means for supporting the tube headers independently behind a tile wall which acts to protect the headers and fittings from the intense heat of the combustion zone and from the oxidizing effect of the combustion gases. Furthermore, the headers and their supports and tubes are free to expand or contract in accordance with the temperature changes in the furnace.

The nature and objects of the present in vention having thus been set forth and a specific illustrative embodiment of the same given, what is claimed and desired to be secured by Letters Patent is:

1. In a furnace, the combination comprising bottom, top and side walls forming a combustion zone in said furnace, tubes disposed across said combustion zone and extending through said side walls, in sealed relation thereto, and provided for longitudinal movement through said walls, header members connecting the ends of each tube with an adjoining tube exteriorly of the combustion zone, and means, independent of said side walls, supporting each of said header members for sliding movement with its connected tubes, with respect to the supporting means and to any other header member.

2. A furnace according to claim 1 wherein said supporting means comprise rollers arranged 4 substantially horizontally, forming a substantially right angle with said tubes.

3. In a furnace the combination comprising bottom, top and side walls forming a combustion zone in said furnace, tubes horizontally disposed across said combustion zone and extending with free play through said side walls, return headers for each end of said tubes horizontally disposed outside said walls and connecting pairs of tubes arranged in the same horizontal plane and individual roller means exterior and independent of said walls for loosely supporting said headers individually and arranged beneath and substantially parallel to said headers, said headers being free to move independently from the motions of any other header and without affecting the means supporting any other header.

' JOHN E. DONAH'UE. LEO W. SCHRADER.