JPS6237696A - Heat transfer tube fixing device - Google Patents

Abstract

PURPOSE:To permit to carry out radiation inspection easily by a method wherein a protuberance is formed on the peripheral rim of through hole of a tube plate and the inserting end of the heat transfer tube is welded to the end of the protuberance. CONSTITUTION:The protuberance 5, having preset thickness (t) and length (l), is provided on the inserting side of the heat transfer tube 1 of the through hole 4, bored on the tube plate 2. One end of the heat transfer tube 1 is inserted into the protuberance 5 and is fixed to the protuberance 5 through seal welding effected to the welding section 3. An X-ray film 6 is placed immediately below the welding section 3 and radiation X is emitted from a radiation source 7 through the part to be inspected whereby the radiation inspection of the welding section 3 may be effected. In another case, the protuberance 5 iis made by cutting a groove 8 at the inserting side of heat transfer tube 1 of the tube plate 2. The radiation inspection for the welding section 3 is effected by emitting radiation X from the radiation source 7 arranged in the heat transfer tube 1 through the inspecting section. In this case, the X-ray film 6 is placed in the groove 8 cut on the tube plate 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improved heat exchanger tube fixing device for, for example, a heat exchanger tube and a tube plate in a heat exchanger.

[Technical background of the invention and its problems]

A large number of heat exchanger tubes in a heat exchanger or a heat exchange section of a feed water heater have both ends fixed to a tube plate by welding. That is, as shown in FIG. 4, the heat exchanger tube 1 is sealed by welding after inserting part (solid line) or the entire tip (dashed line) into the through hole 4 drilled in the tube plate 2. It is fixed to the tube sheet 2 by welding by the section 3. In particular, in a heat exchanger having tube sheets at both ends, it is necessary to insert the heat exchanger pipes through the through holes 4 of the tube sheet 2, so a fixing method as shown in FIG. 4 is usually adopted.

Conventionally, penetrant testing and magnetic testing have been used as non-destructive testing methods for such seal welds 3, but both methods are methods for inspecting defects on or near the surface of seal welds 3. Therefore, it is not possible to inspect for defects inside the seal weld 3.Also, volumetric inspection methods such as ultrasonic flaw detection have been used, but this method has the problem of poor reliability.

On the other hand, the radiation inspection method is the most reliable method compared to the above-mentioned method, but it
With a fixed shape, there is no need to place a film or a radiation source, and the thickness of the part to be inspected varies greatly, requiring special radiation sources and jigs, which requires a large amount of inspection time and cost. did.

In this way, radiographic inspection cannot be easily carried out on the welded part between the tube and the tube sheet due to the conventional fixed shape.
It was difficult to confirm the soundness of the weld.

[Purpose of the invention]

An object of the present invention is to provide a heat exchanger tube fixing device that allows a heat exchanger tube to be inserted through a temporarily bored through hole and that allows easy radiographic inspection.

[Summary of the invention]

The heat exchanger tube fixing device according to the present invention has a through hole having a predetermined wall thickness and length on the heat exchanger tube insertion side of the tube sheet and into which the end of the heat exchanger tube is inserted, at the joint between the heat exchanger tube and the tube sheet. It is characterized in that a protrusion having a hole is formed, and the protrusion and the insertion end of the heat exchanger tube are joined by welding.

[Embodiments of the invention]

The present invention will be explained below based on the embodiments shown in FIGS. 1, 2, and 3. In FIG. 1, a protrusion 5 having a predetermined wall thickness t and a length 1 is provided on the insertion side of the heat exchanger tube 1 of a through hole 4 formed in a tube plate 2. Heat exchanger tube 1 is attached to this protrusion 5.
Insert and secure the end of the The heat exchanger tube 1 and tube plate 2 are fixed by seal welding the welded portion 3.

This welded portion 3 is obtained by seal-welding the entire circumference from the outer or inner surface of the tube to the groove portion formed by the insertion portion of the projection 5 of the heat exchanger tube 1 and tube sheet 2. Regarding this seal welding part 3, an XAI film 6 is placed directly under the seal welding part 3, and radiation X is emitted from a radiation source 7 placed outside the tube to this X-ray film 6 through the inspected part. , radiation inspection of the seal weld 3 becomes possible.

In another embodiment shown in FIG.
It is made by cutting a film groove 8 on the insertion side of the heat exchanger tube 1. The radiation inspection of the welded part 3 in this embodiment is carried out by emitting radiation X from a radiation source 7 placed inside the heat exchanger tube 1 through the part to be inspected. It will be placed in the film holding groove 8 made by cutting 2.

In another embodiment shown in FIG. 3, the tip of the heat exchanger tube l is inserted by a dimension Q/2 into the inside of the protrusion 5 machined on the tube plate 2, and the tip of the protrusion 5 and the end of the heat exchanger tube 1 are They are joined at either or both of the welded parts 3,3. In this embodiment, an xm film 6 is placed outside the projection 5, and X-rays are emitted from a radiation source placed outside the tube as shown in FIG. It is possible to perform radiological examinations.

〔Effect of the invention〕

As described above, in the present invention, at the joint between the heat exchanger tube and the tube sheet, a protrusion having a predetermined thickness and length is formed at the periphery of the through hole in the tube sheet, and the through hole of the protrusion and the heat exchanger tube are connected to each other. The inserted end of the heat exchanger tube and the end of the protrusion were welded simultaneously or separately, and an X-ray film was pasted on the outside of the protrusion and placed inside and outside the tube. By emitting X-rays from the radiation source to the welded part of the inspected part, the soundness of the welded part can be easily confirmed by radiation inspection.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a heat exchanger tube fixing device according to the present invention, FIGS. 2 and 3 are cross-sectional views showing other different embodiments of the present invention, and FIG. 4 is a cross-sectional view showing a conventional heat exchanger tube fixing device. It is a sectional view showing a fixing device. l...Heat transfer tube 2...Tube sheet 3...Welded part 4...Through hole 5...Protrusion
6...X-ray film 7...Radiation source @ Figure 1 @ Figure 2 Figure 3 Figure 4

Claims (4)

[Claims] (1) At the joint between the heat exchanger tube and the tube sheet, a protrusion with a predetermined wall thickness and length and a through hole into which the end of the heat exchanger tube is inserted is formed on the heat exchanger tube insertion side of the tube sheet. A heat exchanger tube fixing device characterized in that the protrusion and the insertion end of the heat exchanger tube are joined by welding. (2) The heat exchanger tube fixing device according to claim 1, wherein the protrusion is formed to protrude from the side surface of the tube plate. (3) The protrusion is formed by cutting an X-ray film groove on the side surface of the tube plate.
Heat exchanger tube fixing device as described in Section 2. (4) The heat exchanger tube fixing device according to claim 1, wherein the welded portion is set at both or one of the insertion end and the protrusion end of the heat exchanger tube.