RU1810146C - Method for manufacturing multichannel tubes - Google Patents

Abstract

Usage: production of tell-tube tubes, which are the main structural elements of evaporators of refrigeration machines and units. SUMMARY OF THE INVENTION: A core composed of several segments is inserted into a tubular shell with ribs along the longitudinal axis of the core. Preliminarily, annular grooves are made at the ends of adjacent segments of the core facing each other, and circular cuts to a depth of not less than the height of the rib are made at a distance of the width of the groove. After insertion of the core into the shell, drawing is carried out. 4 sludge. 1 tab.

Description

The invention relates to the processing of metals by pressure, in particular to the drawing production of multi-channel pipes for evaporators of refrigeration machines.

The purpose of the invention is to simplify manufacturing and increase yield.

In FIG. 1 shows a longitudinal view of a multi-channel pipe before drawing; figure 2 is a cross section in figure 1; Fig. 3 is a longitudinal view of a multi-channel pipe after drawing; figure 4 is the same, cross section.

The method is implemented as follows.

On the core with longitudinal ribs 1, circular grooves 3 of width B are made sequentially along the drawing line at the turning points of the length I, and then, at a distance of the groove width, there are diametrical cuts 4 to a depth not less than the height of the rib 5 to the core 6. Next, the core 1 is introduced with a gap in the shell 2 and carry out their connection by drawing.

During the drawing process, the longitudinal ribs 5 in the area between the groove 3 and the notch 4 lose radial stability. This leads to a torque and, accordingly, to the rotation of the segments in the groove portion relative to each other in the circumferential direction by an angle a. Since the ribs lose stability during the longitudinal movement, they take the form of a spiral. The spiral of the ribs provides rotation and turbulization of the heat-transfer medium in the channels between the segments of the core. The rigid construction of the core eliminates misalignment of the segments within the shell relative to each other. The width of the annular groove is recommended to be taken within the length of the deformation zone during drawing. The presence of an annular groove on the ribs during operation allows the heat exchange medium to flow between adjacent channels inside the pipe and equalize the heat transfer conditions in the various channels.

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A multivariate experiment was conducted to predict the angle of rotation of core segments. As billets, a cylindrical shell made of metal sheets with a size of 22 x 1.2 mm and a core with 10 longitudinal ribs made of AD31 with a core diameter of 4.5 mm, a rib thickness of 1.2 mm, and a circumscribed circle diameter of 18.5 mm were used. The mechanical properties of the core and cladding materials corresponded to the annealed state. The core was taken with a length of 800 mm consisting of 2 segments separated by an annular groove and a diametrical notch. The experiments were carried out according to the scheme of a fractional factor experiment. We studied the influence of the following factors on the angle of rotation of the core segments relative to each other: xi is the amount of compression of the rib L h 0.25 ... 0.75 mm, X2 is the width of the annular groove B is 3-6 mm, xs is the diameter of the core, d 3 -5 mm. The experimental design and its results are shown in the table.

After processing the results of the experiment, the equation

and 11.2 + .6.5x1-5.3x2-6.8x3 ,. xi - 0.5 „X2 - 4.5., xs-4

1

where1 X2

xs:

0.25. 1,5

Analysis of the equation shows that with increasing compression, the angle of rotation increases, and with increasing width and diameter of the core, it decreases. At Ah 0.5 mm; In 4.5 mm; d 3 mm, we obtain an angle equal to half the angle between the ribs, i.e. 18 °.

An example of the implementation of the proposed method is the connection of the workpiece, consisting of a copper shell 22 x

1.3 mm and a core with 10 longitudinal ribs of AD31 2000 mm long. The core was divided into five segments of equal length 400 mm by means of annular grooves. The annular grooves at the turning points of the segments are made on a lathe to a core diameter of 3 mm, the groove width. amounted to 4.5 mm. At a distance of 4.5 mm from the grooves, with the help of a band saw, diametrical cuts of ribs to a heart of diameter 4.5 mm were made, and the core thus obtained was inserted into the shell. The connection of the core with the shell was carried out by drawing through a conical fiber with a diameter of 20.1 mm In the process of drawing, the segments of the cores turned relative to each other by an angle equal to half the angle between the ribs.

Claims (1)

SUMMARY OF THE INVENTION A method of manufacturing a multi-channel pipe, comprising introducing into the tubular sheath a core composed of several segments with longitudinal ribs, turning from the second of each segment relative to the previous one by an angle equal to half the angle between the ribs and connecting the core to the sheath, characterized in that, in order to simplify the manufacture and increase the yield, preliminarily perform an annular groove at the facing ends of adjacent segments of the core and at a distance of. s diametral groove cut to a depth of not less than the height of the ribs, and the rotation of the core segments and connecting the core with the shell is carried out by drawing. 9ig fW Figz Figure 4