JPS6082910A - Pipe expansion rate measuring method - Google Patents

Abstract

PURPOSE:To improve a sticking property and an airtight property by inserting a pipe into an inserting hole, and thereafter, measuring the thickness of the pipe by an ultrasonic reflecting method before and after pipe expansion, and calculating a pipe expansion rate. CONSTITUTION:A pipe 102 is inserted into an inserting hole 101A formed on a pipe plate 101, and after its insertion, pipe expansion is executed, and the pipe 102 is stuck to the pipe plate 101. Before the pipe 102 is inserted into the inserting hole 101A and the pipe expansion is executed, an inner probe 103 which has adopted an ultrasonic reflecting method is inserted into the pipe 102. An ultrasonic wave V oscillated from an ultrasonic vibrator 104 is reflected by a reflecting mirror 105 and arrives at a pipe expansion object position (H part) of the pipe 102. The thickness of the pipe 102 is measured by a reflected wave from said part, brought to a digital display by an ultrasonic thickness meter 106, and also recorded in a recording meter 107. Subsequently, after the pipe expansion, too, the thickness of the pipe 102 in the H part is measured in the same way. A thickness reduction rate of the pipe 102 is calculated by calculation basing on the thickness measured before and after the pipe expansion of the pipe 102 as mentioned above.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pipe expansion rate measuring method for calculating the pipe expansion rate during pipe expansion.

A conventional example will be explained with reference to FIGS. 1 to 4. First, tube expansion refers to inserting the tube 2 into the insertion hole 7A formed in the tube plate 1 as shown in Fig. 1, expanding the tube 2 mechanically or scientifically, and then expanding the tube 2 at the expanded point. It maintains adhesion and airtightness. In such pipe expansion, the evaluation of the adhesion force and airtightness is based on the wall thickness reduction rate (support) of pipe 2.
This wall thickness reduction rate @) is generally calculated using the following formula.

Thick wall thickness reduction rate of the pipe after expansion t%) = (1-11---→X10
0... (1) Wall thickness of the pipe before expansion As is clear from this formula (T), in order to calculate the rate of decrease in the wall thickness of the pipe, it is necessary to measure the wall thickness of the pipe before and after expansion. There is.

The measurement of the wall thickness of the pipe before and after the pipe expansion will be explained below. First, to measure the wall thickness TO of the tube 2 before expansion, as shown in Fig. 2, before inserting the tube 2 into the insertion hole IA, use a micrometer (not shown) or a cylinder gunner to measure the wall thickness TO of the tube at two points per sheath cross section. The inner diameter (X1 and X2 in the figure) and the tube outer diameter (Y and Y2 in the figure) are measured and calculated indirectly from their average values (X and Y). That is, the wall thickness To of the tube 2 before expansion can be calculated by the following formula.

y y'x+x To = Y −X = −−□・・・・・・ω)2
2 Next, the wall thickness T' of the tube 2 after expansion is determined by measuring the inner diameter (zl and z2) of the insertion hole A at two locations per cross section before inserting the tube 2 into the insertion hole IA, as shown in FIG. Measure. After expanding the tube, the inner diameters X/1 and X'2) of the tube 2 are measured at two locations per cross section as shown in FIG. Then, T' is calculated from these average values (2 and X/). That is, the wall thickness T' of the tube 2 after expansion is as follows.

The wall thickness reduction rate of the tube 2 was calculated by substituting the tube wall thickness To before tube expansion and the tube wall thickness T' after tube expansion calculated from these 2Gl) and proviso) into the above equation (1).

However, this method has the following problems. That is, the wall thickness of the tube 2 before and after expansion is calculated indirectly from the average value of the inner and outer diameters of the tube 2 and the inner diameter of the insertion hole 7A, and the reliability and accuracy are not very high. In addition, it is necessary to measure the diameter of the insertion hole IA and the inner and outer diameters of the tube 2 before inserting the tube 2, and the inner diameter of the tube 2 must be measured after the tube is expanded, which takes a long time. . Furthermore, in the case of the method described above, it is extremely difficult to systemize the method in conjunction with a computer, for example, in order to calculate the wall thickness reduction rate.

The present invention has been made based on the above-mentioned points, and its purpose is to provide a pipe expansion rate measuring method according to the present invention that is highly reliable, accurate, easy to measure, and capable of calculating the wall thickness reduction rate. During tube expansion in which the tube is inserted into an insertion hole formed in a tube plate, the tube is expanded and fixed, the step of measuring the wall thickness of the tube in advance by an ultrasonic reflection method after inserting the tube into the insertion hole and before expanding the tube; This configuration includes a step of opening the wall thickness of the tube by an ultrasonic reflection method after the tube is expanded, and a step of calculating the tube expansion rate from the wall thickness of the tube measured before and after the tube expansion.

An embodiment of the present invention will be described below with reference to FIGS. 5 and 6. Reference numeral 10 in the figure indicates a tube plate. This tube plate
Insert the tube 102 into the insertion hole 101k formed in 01,
After insertion, the tube 102 is expanded and fixed to the tube plate 101.

Next, we will discuss how to determine the wall thickness reduction rate.

First, the wall thickness of the tube 102 before expansion is determined by inserting the tube 02 into the insertion hole 10.
Before inserting into the tube 1A and expanding the tube, an inner probe 103 employing an ultrasonic reflection method is inserted into the tube 102. This inner glove 103 is composed of an ultrasonic transducer 104 and a reflecting mirror 105 placed opposite to this ultrasonic transducer 104. It is reflected and reaches the target position of the tube 102 (indicated by H in the figure). The wall thickness of the tube 102 is then measured in order to absorb the waves reflected therefrom. The measured wall thickness of the tube 102 before expansion is digitally displayed on the ultrasonic thickness gauge 106 and recorded on the recorder 107.

Next, measurement of the wall thickness of the tube 102 after expansion will be described. In this case as well, the inner probe No. 03 used for measuring the wall thickness before pipe expansion is inserted into the pipe 102, and the pipe 102 at the H section is
Measure the wall thickness.

The measured thickness is digitally displayed on the ultrasonic thickness gauge 106 and recorded on the recorder JO7. Then, based on the measured wall thickness of the pipe 102 before and after expansion, the formula (I) shown in the explanation of the conventional example above is used.
) Calculate the wall thickness reduction rate of Q'Nzo2. At this time, as shown in FIG.
If a conbeater 108 and a digital display 109 are inserted between the converter 10B and the digital display 109, the thickness reduction rate is immediately calculated by the conbeater 10B and displayed on the digital display 109.

As described above, according to the tube expansion rate measuring method according to the present embodiment, unlike the conventional method in which the wall thickness of the tube 102 is measured indirectly from the inner and outer diameters of the tube 102 or the inner diameter of the insertion hole 101, the inner globe no. Since it can be directly measured, reliability and accuracy can be greatly improved. In addition, the wall thickness of the tube 102 before and after expansion can be measured with the bone lθ2 inserted into the insertion hole 1oIA of the tube plate 101, and the measurement work is easy because there is no need to make a cut before insertion as in the conventional method. The time required for dovetailing work can be significantly reduced. Furthermore, since it can be systematized using the computer 108, the method of measuring wall thickness is used in tube expansion in which a dish is inserted into an insertion hole formed in a tube plate, and the tube is expanded and fixed. A process of measuring the wall thickness of the tube by ultrasonic reflection method after insertion and before expansion, a step of measuring the wall thickness of the tube by ultrasonic reflection method after expansion, and a process of measuring the wall thickness of the tube before and after expansion. This configuration includes a step of calculating the pipe expansion rate from the thickness.

Therefore, the reliability and accuracy of pipe expansion rate calculation can be greatly improved, the measurement work becomes easier, and systemization using smart computers is possible, which significantly improves the reliability of the evaluation of fixing force and airtightness in pipe expansion. Such effects can be improved in dogs.

[Brief explanation of drawings]

Figures 1 to 4 are diagrams showing conventional examples, and Figure 1 (ty
), 03) is a diagram for explaining tube expansion, Figure 2 (A). (B) is a diagram showing wall thickness measurement before pipe expansion, Figure 3 (A),
(B> and Figures 4 (3) and (B) are diagrams showing the wall thickness measurement after pipe expansion, Figures 5 and 6 are diagrams showing one embodiment of the present invention, and Figure 5 is the wall thickness measurement. Figure 6, which shows the measurement of the reduction rate, is a diagram showing the systemized measurement of the wall thickness reduction rate.
- Tube, yos... Inner zorobe, 104... Ultrasonic vibrator, 105... Reflector. Figure 1 Figure 2 Figure 3 (B) Figure 4 Figure 5

Claims (1)

[Claims] During tube expansion in which a tube is inserted into an insertion hole formed in a tube plate, and the tube is expanded and fixed, the process of measuring the wall thickness of the tube using an ultrasonic reflection method in advance after inserting the tube into the insertion hole and before expanding the tube. and a step of measuring the wall thickness of the pipe (by ultrasonic reflection method) after expanding the pipe, and a step of calculating the expansion ratio from the wall thickness of the pipe measured before and after the pipe expansion. Measurement method.