US3696862A

US3696862A - Industrial furnace

Info

Publication number: US3696862A
Application number: US119243A
Authority: US
Inventors: Jan Van Dijk
Original assignee: Shell Oil Co
Current assignee: Shell USA Inc
Priority date: 1970-03-05
Filing date: 1971-02-26
Publication date: 1972-10-10
Anticipated expiration: 1989-10-10
Also published as: DE2110197A1; NL160652C; FR2084120A5; JPS5338462B1; GB1303387A; NL160652B; NL7003126A

Abstract

Improved heating tube support means for industrial furnaces having heating tubes extending through the furnace wall.

Description

United States Patent 11 1 3,696,862 Dijk 1451 Oct. 10, 1972 [54] INDUSTRIAL FURNACE [56] Relerences Cited [72] lnvemor: Jan Van Dljk, The Hague, Nether- UNITED STATES PATENTS lands 1,541,165 5/1920 Br ans ..165/l78 [73] Assgnee New 2,487,626 11/1949 wi nman 165/178 x [22] Filed: Feb. 26, 1971 3,259,112 7/1966 Lee ..122/510 [21] PP Nu: 119,243 3,496,629 2/1970 Martucc1etal..229/l57.4 UX

Primary Examiner-Frederick L. Matteson [30] Foreign Application Pri rity a Assistant Examiner-Theophil W. Streule March 5, 1970 Netherlands ..70033126 Gmmwa'd and Cdvi 52 us. 01. ..165/l78, 29/1574, 285/158, [571 ABSTRACT 285/413 122/356 Improved heating tube support means for industrial Int. Clfurnaces having heating tubes extending through the [58] Field of Search ..165/178; 29/1574; 285/158,

furnace wall.

4 Claims, 2 Drawing figures INVENTOR JAN VAN DIJK ATTORNEY 1 mnus'rmxr. FURNACE BACKGROUND OF THE INVENTION The invention relates to an industrial furnace for heating liquid or gaseous media in heating tubes which are arranged in rows in the heating space and at least some of which tubes run through openings in the furnace wall and issue outside the heating space. The invention relates in particular to furnaces as used in the processing of petroleum products, such as for keeping intermediary or final products to a specific temperature, or for heating or reheating intermediate products to the conversion temperature.

Furnaces of the above-mentioned type are described, for example, in U.S. Pat. Nos. 2,592,608 and 3,181,508. These known furnaces are so designed that their horizontal cross-section has a rectangular shape. In principle, the present invention may also be applied to furnaces having a horizontal cross-section of circular shape, as described for example in U.K. Pat. No. 841,650.

In such furnaces, particularly those of the vertical type, special attention must be paid to the means employed to secure and support the heating tubes. Generally, these tubes are either supported at the lower end and subsequently secured to the upper end of a guiding member, or suspended from the upper end in the heating space. It is common practice to arrange the ends of the heating tubes, which are generally interconnected, into one or more series or bundles of tubes which issue outside of the heating space proper, for example into headers, or sometimes to form a direct connection with the next series through a pipe bend. This practice of running the series of tubes through the wall of the heating space or of a securing element presents a variety of problems, particularly, in relatively small furnace units. In the first place, it is highly desirable that the heating tubes can be secured and removed in a simple manner. It is also necessary that the wall of the heating space through which the tubes are run is adequately sealed. In addition, thermal stresses which result from the difference in temperature between the heating space and the surroundings can adversely affect materials and hence must be avoided.

It is the object of the invention to provide a simple and inexpensive construction which satisfies the above conditions.

SUMMARY OF THE INVENTION It has now been found that this object can be achieved with a furnace of the type previously mentioned which is characterized in that the openings in the furnace wall to provide passage for heating tubes are each provided with a length of pipe, one end of which is rigidly secured to the fire hearth wall and the other end of which is provided with an outward-facing flange. This outward-facing flange cooperates with a split second flange, the inside diameter of which is substantially equal to the diameter of the heating tube. The split second flange supports the heating tube by way of an annular collar externally-welded to the heating tube, which collar sealingly rests on the split flange. A second annular collar is also provided on the heating tube in the opening arranged in the wall of the fire hearth.

The advantages of the present construction reside in its simplicity and that leakage of flue gases, false draught and the like are completely avoided as the openinm forming the connection with the fire hearth space are fully gas tight. A further advantage is that in furnaces of the vertical type, a separate supporting frame is not required since the heating tubes are supported by the furnace roof in a simple manner. Besides, assembly and removal are simple.

An additional advantage is that repairs are possible without the necessity of having to pull the heating tubes out of the furnace. Repairs can, in fact, be efiected from inside the furnace by pulling the heating tubes into the furnace hearth. This would not be possible in most conventional furnaces of this type.

The above advantages are particularly evident in a described in Netherlands Pat. No.

DESCRIPTION OF THE DRAWING The invention will now be further described with reference to the drawing.

FIG. 1 is a vertical sectional view ofa detail ofa furnace, while FIG. 2 represents a top plan view of it.

In these figures, l designates the furnace wall, viz. part of the roofing, which wall is provided with refractory lining 2 on the fire hearth side. A heating tube 3 is passed outside die furnace through opening 4. A length of pipe 5, having an inside diameter equal to the opening, is rigidly secured to the fire hearth wall. The length of pipe is provided at one end with flange 6 which extends outwards. A split flange (7a, 7b) cooperates with flange 6; the split flange has an inside diameter which is substantially equal to the diameter of the heating tube 3. Adjusting cams l0 cooperate with the split flange and support annular collar 8 which is welded on the heating tube 3. A second collar (collar 9), which is also welded to the heating tube, is positioned in opening 4. The space between the inner-most collar and the split flange is filled with packing 11. This packing may consist of any suitable material, such as refractory material like that of the lining. Preferably, the packing consists of renewable heat-resisting material, such as asbestos, rockwool," or the like.

The adjusting cams serve to keep the distance between outer collar 8 and the upper side of flange 6 large enough to allow the packing to be inserted. Only after this is done is the split flange fitted by lifting the heating tube slightly.

From the foregoing description it can be seen that the construction according to the invention is not only simple, but also facilitates maintenance of the furnace. For example, if it is necessary to work in the fire hearth space behind the heating tubes (e.g., when repairing the lining or carrying out welding work on the bundles of tubes or on the furnace wall), the heating tubes may be pulled aside, viz. into the fire hearth space.

However, it is not always necessary to remove the packing since the channels of the series of tubes are normally arranged in panels of which the wall of the tire hearth space is composed. These panels are detachable and can be removed in their entirety together with the series of tubes. A detachable panel of this type can also be used as a hoisting girder.

Although the invention is particularly suitable for use in furnaces in which the heating tubes are arranged vertically in the heating space, in principle, it is also possible to use the invention with horizontal heating tubes. in a horizontal furnace, heating tube 3 as shown in the drawing would not be supported by collar 8 resting on the flange 7a, lb, (or the adjusting earns 10), but would be directly supported by the tube itself resting on the

flange

7a or 7b.

I claim as my invention:

1. in an industrial furnace for heating liquid or gaseous media in heating tubes which are arranged in rows in the heating space, and at least some of which tubes run through openings in the furnace wall and issue outside of the heating space, an improved support for said heating tubes which comprises:

i. a length of pipe having an inside diameter equal to the diameter of the opening in the furnace wall, one end of which pipe is rigidly secured to the fire hearth wall of the furnace, and the other end of which is provided with an outwardfacing flange extending outside of the furnace wall;

2. a split flange resting on said outward-facing flange having an inside diameter substantially equal to the diameter of the heating tube;

3. two annular collars extemally-welded on the heating tube having outside diameters less than the diameter of the opening in the furnace wall, the outer of which annular collars sealingly rests on said split flange thereby supporting the heating tube, the inner annular collar defining with the exterior wall of the heating tube and the interior wall of the pipe an elongated annular space.

2. The improved furnace of claim 1 wherein the tubes are vertically arranged and are suspended from the top wall of the furnace.

3. The improved furnace of claim 2 wherein the outer externally-welded collar sealingly rests on a plurality of adjusting cans arranged on the split flange and distributed over its periphery.

4. The improved furnace of claim 2 wherein the elongated annular space defined by the inner externallywelded annular collar and the exterior wall of the heating tube and interior wall of the pipe is filled with renewable heat-resisting sealing material.

Claims

1. In an industrial furnace for heating liquid or gaseous media in heating tubes which are arranged in rows in the heating space, and at least some of which tubes run through openings in the furnace wall and issue outside of the heating space, an improved support for said heating tubes which comprises: 1. a length of pipe having an inside diameter equal to the diameter of the opening in the furnace wall, one end of which pipe is rigidly secured to the fire hearth wall of the furnace, and the other end of which is provided with an outwardfacing flange extending outside of the furnace wall; 2. a split flange resting on said outward-facing flange having an inside diameter substantially equal to the diameter of the heating tube; 3. two annular collars externally-welded on the heating tube having outside diameters less than the diameter of the opening in the furnace wall, the outer of which annular collars sealingly rests on said split flange thereby supporting the heating tube, the inner annular collar defining with the exterior wall of the heating tube and the interior wall of the pipe an elongated annular space.

3. The improved furnace of claim 2 wherein the outer externally-welded collar sealingly rests on a plurality of adjusting cams arranged on the split flange and distributed over its periphery.

3. two annular collars externally-welded on the heating tube having outside diameters less than the diameter of the opening in the furnace wall, the outer of which annular collars sealingly rests on said split flange thereby supporting the heating tube, the inner annular collar defining with the exterior wall of the heating tube and the interior wall of the pipe an elongated annular space.

4. The improved furnace of claim 2 wherein the elongated annular space defined by the inner externally-welded annular collar and the exterior wall of the heating tube and interior wall of the pipe is filled with renewable heat-resisting sealing material.