JPH03268816A - Manufacture of heat transfer tube - Google Patents

Abstract

PURPOSE:To form a metallic strip having an asymmetric groove pattern making spiral grooves retaining distortion and warpage, to manufacture an accurate tube with two tube manufacturing equipments and to enable reliable welding by dividing and cutting a metallic strip having a width equivalent to the peripheral length of a heat transfer tube. CONSTITUTION:The metallic strip 21 provided with a width 2W twice the equivalent of the peripheral length of the heat transfer tube is delivered from a delivering device 23. Then, grooves 34 having a fixed lead angle each on the surface are formed in a symmetrical pattern in the longitudinal direction through between a working roll 26 and rolling rolls 27a-27c of a working device 24. Further, after this metallic strip 21 is divided by the cutter 29 of a cutting device 28 into two parts or into metallic strips 21a, 21b having a width W each equivalent to the peripheral length of the heat transfer tube 22 and forms asymmetric groove pattern having a fixed lead angle making spiral grooves 35, the metallic strips 21a, 21b are formed by the forming rolls 31a-31j, 32a-32j of the two parallel manufacturing equipments 30a, 30b respectively into a tubular shape and both edge sides are welded by high frequency induction coils 33a, 33b to form final heat transfer tubes 22a, 22b.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to the manufacture of heat exchanger tubes used in heat exchangers that transfer heat between fluids such as refrigerant and air, such as air conditioners, refrigeration equipment, and automobile equipment. It is about the method.

Conventional technology In recent years, heat exchanger tubes have been required to have more complex inner shapes due to faster processing speeds and improved performance.
As disclosed in Japanese Patent No. 092, it has been put into practical use to produce a heat exchanger tube with internal grooves by forming grooves on a metal strip and then welding both edges.

Hereinafter, a method for manufacturing the conventional heat exchanger tube described above will be explained with reference to the drawings.

5 to 10 show the manufacturing process of conventional heat exchanger tubes.

In the figure, reference numeral 1 denotes a metal band plate, which has a circumferential half width W of the heat exchanger tube 2. 3 is a rolling device that continuously rolls the metal strip 1; 4 is a processing device; the processing roll 6 has a forming groove 5 having a symmetrical pattern on its surface with a constant lead angle;
and rolling rolls 7a to 7c that are press-welded thereto.

8 is a pipe making device, forming rolls 9a for forming the metal strip 1 into a pipe;
~9j and a high frequency induction coil 10 to which both edges of the metal strip 1 are welded. In addition, a feeding device 3, a processing device 4
, the tube making device 8 is a continuous process.

In the manufacturing process of the heat exchanger tube configured as described above, after the asymmetrical groove pattern with the lead angle is formed, the metal strip 2
1a and 21b are two pipe making devices 30a arranged in parallel.
, 30b forming rolls 31a-31j, 32a-32j
high frequency induction coils 33a, 3.
Final heat transfer with both edges welded by 3b? 22a, 2
2b, respectively. At this time, in the processing device 24, the metal strip 21 is formed into grooves 84 in a symmetrical pattern with respect to the longitudinal direction.
is processed, distortion and warping can be suppressed, and even if the heat transfer tube 22 is divided into circumferential optical widths W by the cutting device 28 and an asymmetrical groove pattern is formed, the pipe can be manufactured in the next process without distortion or warping. Accurate pipe making and reliable welding are performed by the devices 30a and 30b.

As described above, according to this embodiment, the heat exchanger tube 220 to be formed
A groove 34 having a constant lead angle with respect to the longitudinal direction is formed on the surface of the metal strip 21 having a radius 2W that is approximately twice the circumferential equivalent width W.
A single processing device 24 is used to cut the metal strip 21 into two parts along the longitudinal direction, and cut the metal strip 21 into two parts along the longitudinal direction.
Two symmetrical metal strips 21a, 21 with a circumferential light width W of
One cutting device 28 for forming b, and the divided two
By interlocking two pipe making devices 30a and 3ob that form the metal strips 21a and 21b into a tube shape and weld both edges of each metal strip 21a and 21b, the processing device 240 stage As in the past, the pattern of the grooves 34 is almost symmetrical with respect to the longitudinal direction, so the metal strip 21 can be processed with less distortion and warping, and the cutting device 28 in the next process cuts the circumferential optical width W of the heat exchanger tube 22. By cutting the metal strip 21 into pieces in the longitudinal direction, the metal strips 21a and 21b having an asymmetrical groove pattern can be formed to create the spiral grooves 35 while suppressing distortion and warping. 30b allows for highly accurate pipe making and reliable welding.
The heat exchanger tube 22 with the inner spiral groove 35 shown in FIG. 2 can be formed. Also, the inner spiral groove 35 shown in FIG.
As shown in FIG. 3, the heat transfer tubes 22 with attached heat transfer tubes can improve the heat transfer coefficient by bringing the flow pattern of the refrigerant in the tube closer to an annular flow, and this effect is particularly large at low refrigerant circulation rates.

Effects of the Invention As described above, the present invention provides symmetrical grooves having a constant lead angle with respect to the longitudinal direction on the surface of a metal strip having a width approximately twice the circumferential phase width of the heat exchanger tube to be formed. One processing device, one cutting device that cuts the metal strip into two along the longitudinal direction and forms two metal strips symmetrical in circumferential light width of the heat exchanger tube; By linking the two pipe-making machines that form the above-mentioned two metal strips into a tube shape and weld both edges of each metal strip, the groove pattern can be created in the same manner as before at the processing equipment stage. Since the shape is almost symmetrical with respect to the longitudinal direction, it is possible to process the metal strip with less distortion and warpage, and in the next step, the cutting device can be used to cut the metal strip into pieces in the longitudinal direction along the circumferential light width of the heat transfer tube. This makes it possible to form metal strips with asymmetrical groove patterns that create spiral grooves while suppressing distortion and warping, and allows highly accurate pipe making and reliable welding to be performed using two pipe making machines. It is possible to form high-performance heat exchanger tubes with internal spiral grooves on the sides.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a method of manufacturing a heat exchanger tube in an embodiment of the present invention, FIG. 2 is a perspective view showing the shape of a heat exchanger tube formed by the manufacturing method of FIG. 1, and FIG. FIG. 4 is a vertical cross-sectional view of FIG. 2, and FIG. 5 is a perspective view showing a conventional method of manufacturing a heat exchanger tube.
Fig. 6 is a perspective view showing the shape of the heat exchanger tube formed by the manufacturing method shown in Fig. 5, Fig. 7 is a cross-sectional view showing the refrigerant flow pattern of the heat transfer tube shown in Fig. 6, and Fig. 8 is the same as Fig. 6. FIG. 9 is a cross-sectional view corresponding to FIG. 7 showing a state in which a small amount of refrigerant is contained, and FIG. 10 is a vertical cross-sectional view of FIG. 9 corresponding to FIG. 8. 21... Metal strip plate, 22... Heat exchanger tube, 24... Processing device, 28... Cutting device, 30... Pipe making device, 34...
・Groove, 35...Spiral groove.

Claims (1)

[Claims] A processing device that symmetrically forms grooves having a constant lead angle with respect to the longitudinal direction on the surface of a metal strip having a width approximately twice the circumferential half width of the heat exchanger tube to be formed, and the metal strip. A cutting device that cuts a plate into two parts along the longitudinal direction and forms two symmetrical metal strips with half the circumferential width of the heat exchanger tube, and A method for manufacturing a heat exchanger tube in which a spiral groove is formed on the inner surface of the tube by interlocking two tube-making apparatuses that form the tube into a tube shape and weld both edges of each metal strip.