GB2126058A

GB2126058A - Tube heating device

Info

Publication number: GB2126058A
Application number: GB08318045A
Authority: GB
Inventors: Douglas Gray Harman
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1982-07-12
Filing date: 1983-07-04
Publication date: 1984-03-14
Also published as: JPS5932795A; GB8318045D0; GB2126058B; JPS6238640B2

Abstract

A tube heating apparatus for localized heating of a tube by passing an incandescent lamp (20) through the tube (12) to the region of the tube (12) which is to be heated includes means (22, 28) permitting accurate positioning of the lamp (20) at the zone of the tube (12). The heating apparatus utilizes a tungsten filament lamp (20), a socket (16) receiving the lamp (20) and an extension rod (22) which is attached to the socket (16) and marked with linear gradations which permit the lamp (20) to be precisely located along the length of the tube's bore. <IMAGE>

Description

SPECIFICATION Tube heating device Many different types of apparatus, such as heat exchangers generally and steam generators specifically, utilize a plurality of tubes within their structure. Occasionally, either during the manufacture of the apparatus or during its repair, it becomes necessary to locally heat a specific region of one of the tubes. This operation can be necessitated by a requirement to either perform stress relieving or to provide sufficient heat for brazing or soldering. When the tubes of the apparatus are closely associated to each other, it occasionally becomes very difficult to heat one tube locally without affecting adjacent tubes.

Also, the close proximity of adjacent tubes or other components may obstruct access to the specific region of a tube which is to be heated. Under these circumstances, the easiest method of applying heat to a particular location of a tube is to gain access to that localized region through the inside of the subject tube.

Localized heating can therefore be achieved by positioning a heat source within a particular tube, positioning the heat source at the proper location within the tube and heating the localized region from the inside of the tube. Typical heat sources for this type of operation comprise electrically inductive apparatus and combustion devices.

The present invention relates generally to the repair of tubular structures and, more particularly, to the localized heating of one of a plurality of tubes of a heat exchanger.

The present invention utilizes a high-intensity incandescent lamp, such as a tungsten-element lamp, to locally heat a tube from within its internal bore. The lamp must be shaped to fit within the inside bore of the tube with a sufficient clearance around the lamp to permit it to move in sliding relation within the tube.

A socket is provided which is shaped to receive the lamp and which is also shaped to fit within the tube in sliding relation therewith. Means for disposing the incandescent lamp at a preselected distance from one end of the tube is also provided. This disposing means can comprise a rod of a preselected length which is shaped to be attached to the socket and fit within the inside bore of the tube. The socket can be any suitable device which permits the lamp to be connected to the disposing means while being supplied with electrical power.

An electrical power supply is provided which, through a preselected length of an electrical conductor, provides electrical power to the filament of the incandescent lamp. Means are also provided for determining the position of the lamp within the tube to a reasonable accuracy. In the preferred embodiment, this determining means can comprise a plurality of marks on the outside surface of the rod. These marks serve as linear gradations so that an operator can accurately determine the position of the incandescent lamp, relative to a preselected end of the tube.

The present invention provides an inexpensive but effective way of presenting a localized heat source to a preselected position of a tube. It allows an operator to accurately position the heat source inside the tube. The present invention, by approaching the desired location from inside the tube, avoids.potential interference which might be caused by adjacent tubes.

For a detailed description of the invention, reference is made to the drawings wherein: Figure 1 illustrates the present invention being used to locally heat a portion of a tube; and Figure 2 shows the present invention locally accessing a portion of a particular one of a plurality of tubes in a tubesheet.

The present invention relates generally to an apparatus and method for heating a localized region of a tube and, more particularly, to an apparatus for heating, for the purposes of manufacture or repair, a particular region of a preselected one a plurality of tubes of a heat exchanger apparatus.

Figure 1 illustrates the present invention being utilized to heat a localized area Z of a tube 12.

The localized zone Z may require heating in order to stress relieve that particular portion of the tube 12, to provide sufficient heat to metallurgically bond the tube 12 to an exteral member such as a tubesheet or to raise the temperature of this portion of the tube 12 to a sufficient magnitude to permit a metallurgical repair of a flaw in this region.

The present invention comprises a means for delivering an incandescent lamp 14 to the target region Z. In the preferred embodiment, this delivering means comprises a socket 1 6 to which the lamp 14 can be attached such as by the use of associated threads 1 8 or any other suitable methods. The incandescent lamp 14 comprises an internal filament 20 which, in the preferred embodiment, is tungsten.

Attached to the socket 1 6 is a rod 22 which is sufficiently long to traverse the distance D between a preselected end of the tube and the zone Z which is to be heated. It should be understood that, although the preferred embodiment of the present invention utilizes a generally stiff rod 22 to traverse the distance D so as to be independent of the attitude of the tube 12 and the consequential gravitational forces on the lamp 14, a flexible means can be used where circumstances permit.

An electrical power source 24 is provided which is capable of supplying sufficient electrical power, through lines 26, to cause the filament 20 of the incandescent lamp 14 to glow and radiate heat toward the zone Z of the tube 12 which is to be heated. Any suitable power source should be considered within the scope of the present invention.

In order to accurately position the lamp 14 at the zone Z, which is a distance D from a preselected end of the tube 1 2, a plurality of marks 28 are provided on the outer surface of the rod 22. These marks 28 designate gradations of their distance from the lamp 1 4 measured along the rod 22. By aligning the end of the tube 12 with the desired mark 28, an operator can easily position the lamp 1 4 a distance D from the end of the tube 12 and, therefore, assure that the lamp 14 will provide radiant heat in the localized target zone area Z.

In Figure 1, the rod 22 is shown as being hollow with the conductors 26 passing through its central bore. It should be understood, however, that this provision of a bore and the positioning of the conductors 26 within the bore of the rod 22 is done as a convenience and is not a requirement of the present invention. The conductors 26 could also be disposed alongside the outside surface of the rod 22 within the tube 12 and remain within the scope of the present invention.

Figure 2 illustrates the present invention being used to provide localized heat to a particular target zone Z of a tube 12 which is disposed among a plurality of other tubes 112. It should be apparent that if the tube 12 is positioned within a plurality of other tubes 112 located on all sides of it, circumstances could easily arise that would make it exceptionally difficult to provide heat to the outside surface of the tube 1 2 in the zone Z.

In Figure 2 the tubes are shown passing through a tubesheet 30 which can further obstruct access to the target zone Z. The present invention with its lamp 14, socket 1 6 and rod 22, permits access to the zone Z without interference from the tubes 112. The socket 16 is shaped to fit within the inside diameter 32 of the tube 12 so as to permit a sliding relation therebetween. It should be apparent that, in order to prevent degradation or damage to the lamp 14, it is beneficial that the socket 1 6 be shaped in such a way so as to avoid contact between the lamp 1 4 and the inside diameter 32 of the tube 12. This can be accomplished by sizing the socket 1 6 to closely approximate, but be less than, the size of the inside diameter 32.When the socket 16 is not able to be shaped accurately in this way, sizing members 40 can be used to adjust for this discrepancy. The sizing members 40 can be formed in the outer surface of the socket 16 or, as in the case of O-ring washers, attached to its outer surface.

An electrical power supply 24 is shown providing a source of electrical power to the socket 1 6 through the conductors 26. The conductors in Figure 2 are shown passing through the bore of the tube 12 alongside the rod 22 but, it should be understood that, these conductors 26 could also be passed through a central bore of a hollow tube 22 as shown in Figure 1.

The present invention as shown in Figure 2, is provided with a sliding indicator 42 which is designed to be associated with the rod 22 in sliding relation and provide a means for facilitating an accurate reading of the marks 28 on the outer surface of the tube 22. The sliding indicator 42 is shaped in such a way that it can abut one end of the tube 12 and permit the rod 22 to slide through it in such a way that it indicates, by aligning with a particular one of the plurality of marks 28, the exact distance between the sliding indicator 42 and the central portion of the lamp 14.Therefore, it should be apparent that, by predetermining the exact distance between ths end of the tube 12 and the target zone Z to be heated (reference number D in Figure 1), an operator can set the sliding indicator 42 to a predetermined one of the plurality of marks 28, rigidly fasten it to the rod 22 and then pass the lamp 14, socket 1 6 and rod 22 into the tube 12 until the sliding indicator 42 abuts the end of the tube 12.

It should be understood that although the present invention has been described in considerable detail and with significant particularly, it should not be considered to be so limited. Furthermore, it should be understood that although the present invention has been described specifically in terms of its preferred embodiment, other alternate embodiments should be considered within the scope of the present invention.

It should be apparent that the present invention provides an apparatus and method for heating a localized region of a tube from the inside of that tube in such a way so as to avoid interference with adjacent tubes and to also permit the localized heating to be done precisely as measured from a preselected end of the tube to be heated.

Claims

1. A tube heating apparatus, comprising: a socket receiving an incandescent lamp and shaped to fit inside said tube in sliding relation with said tube, and means (24, 26) for providing electrical power to said socket, characterized by means (22) attached to said socket for extending said socket a preselected distance into said tube; and means (22, 28) for measuring the distance between a preselected end of said tube (12) and said socket (16).

2. An apparatus as claimed in claim 1, characterized in that said measuring means (22, 28) comprise a plurality of marks (28) on said extending means (22).

3. An apparatus as claimed in claim 1 or 2, characterized in that said extending means (22) is a generally rigid rod (22), one end of said rod (22) being attached to said socket.