JPS6157087B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a heat exchange tubular body.

In general, heat exchanger tubes aim to improve efficiency by increasing the heat transfer area on the inside or outside depending on the purpose.
Recently developed heat transfer tubes have been developed in which fins are provided with protrusions that are intermittently cracked or electrodeposited. However, the need for heat transfer is not only on the outside of the tube, but also on the inside of the tube, and the need for heat transfer is greater in heat exchange mechanisms that use low-temperature boiling media, etc. Heat exchange tubular bodies are already known (e.g.
(Japanese Patent Application Laid-open No. 116765/1983, Japanese Patent Application Laid-open No. 43360/1983).

An object of the present invention is to form deep and clean grooves in a metal strip plate, thereby producing a heat exchange tubular body with excellent steam condensing performance.More specifically, the present invention has the following features: forming a large number of tooth-like chevrons on the metal strip through steps i) and (ii); and forming the metal strip into a C-shaped tube using a forming roll so that the tooth-like chevrons form the inner wall. The present invention relates to a method for manufacturing a heat exchange tubular body, which comprises the step of welding the joining points of both edges of the C-shaped tubular material molded into the C-shaped tubular shape.

(i) A tool roll with machining grooves parallel to the direction of travel of the metal strip, or a tool roll with multiple machining grooves symmetrically inclined with respect to a plane passing through the center of the tool roll and perpendicular to its axis. The process of forming deep grooves using a tool roll.

(ii) Many grooves are inclined symmetrically with respect to a plane passing through the center of the tool roll and perpendicular to its axis, and the direction of inclination is opposite to the direction of inclination of the machined grooves of the tool roll described in (i) above. A process of forming deep grooves using a tool roll provided with grooves.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of an apparatus for carrying out the manufacturing method of the present invention, in which a large number of rolls are arranged along a path through which a metal strip 1 is fed. 2 and 3 are a pair of guide rolls, 4 and 6 are tool rolls, and the tool rolls 4 and 6 are provided with processing grooves for processing the surface of the metal strip 1. 5 and 7 are support rolls for the tool rolls 4 and 6, respectively. 10,
, 25 are forming rolls that gradually form the metal strip into a tubular body. 26, 27 are a pair of seam guide rolls, 28 is a high frequency induction coil, 29,
30 is a pair of squeeze rolls. A resistance welding contactor may be used instead of the high frequency induction coil 28.

In order to process the surface of the metal strip 1 to form a toothed chevron, it is necessary to take a suitable forming means depending on the hardness of the metal. Figure 2a shows the processing means used in the case of soft metals. On the surface of the tool roll 4, there are a large number of machined grooves 31, 31, . . . , 32, 32, .
...is provided. Looking at this in FIG. 2c, we can see that the machined grooves 31 and 32, which are inclined at an angle θ with respect to the advancing direction of the metal strip 1, pass through the center O of the tool roll 4 and are _{perpendicular} to the axis _E1OE2 . A large number of strips are provided symmetrically with respect to Y.

When the metal strip 1 passes between the tool roll 4 and the support roll 5, it is strongly pressed by both rolls, and is coined by the processing grooves 31 of the tool roll 4 within a very short time to form the protrusions 35. is formed. If we consider the transmission of force in the vicinity of an arbitrary point P on line segment ₁ at that time, the machined groove 31 and the protrusion 35 will mesh as if helical gears mesh within that extremely short time. , processing groove 31
transmits a force N in a perpendicular direction to the protrusion 35 (Fig. 2c). The force N has a component force of N cos θ in the direction of line segment ₁ , and if the sum of N cos θ over the range of line segment ₁ is F ₁ , then F ₁ =ΣN cos θ.

Similarly, the force F ₂ applied to the metal strip 1 in the range of ₂ processed grooves 32 is F ₂ =ΣNcosθ, and the direction of the force is opposite to F ₁ .

In this way, F ₁ and F ₂ are balanced, so
The metal strip 1 does not move in its width direction ( _{1 2} direction) (the metal strip does not meander),
Since coining is performed under such a kind of constrained condition, a sufficiently deep groove can be neatly formed. Processed surface 1 thus formed
An enlarged view of part A of a is shown in FIG.

The surface of the tool roll 6 shown in FIG. 2a also has a large number of machined grooves 33, 33, . , 34, 34, . . . are provided. In this embodiment, the machining grooves 33 and 34 are provided approximately at right angles to the machining grooves 31 and 32 of the tool roll 4, respectively. When the processed surface 1a of the metal strip 1 passes between the tool roll 6 and the support roll 7, the parallel protrusions 35, which are formed on the processed surface 1a by the processed grooves 33 and 34, 3
5, . . . are coined so as to be cut approximately at right angles by the processing grooves 33, 34 of the tool roll 6, thereby forming tooth-like chevrons 36, 36, . Figure 4 shows the workpiece surface 1 coined by the tool roll 6.
It is an enlarged view of part B of b.

Since the widthwise components of the force applied by the tool roll 6 to the metal strip 1 are also balanced on both sides of the plane Y, deep grooves can be neatly formed.

The metal strip 1 is formed into a C-shaped tube by successively passing through forming rolls 10, 11, .
The joining point of both edges of the C-shaped tubular material heated by 8 and molded into the C-shaped tubular shape is squeeze roll 2.
The heat exchanger tube T is obtained by pressure welding and joining by steps 9 and 30.
The heat exchanger tube T is normally cut while passing through a cooling device, sizing rolls, and a turquoise head.

The present invention is based on the fact that the widthwise component forces F ₁ and F ₂ applied to the metal strip 1 are balanced, so that the metal strip 1 is formed into a tubular shape while progressing straight without shifting. , it is possible to manufacture high-quality ERW pipes without distortion.

FIG. 5 is a partial sectional view of the manufactured heat exchanger tube T, and FIG. 6 is an enlarged view thereof. The toothed ridges 36, 36, . condensed into.

FIG. 7 shows an embodiment in which one tool roll 6 is provided with a large number of machined grooves that are symmetrically inclined with respect to a plane that passes through the center of the tool roll and is perpendicular to its axis. In this embodiment, a tool roll 44 provided with machining grooves 41, 41, . . . in a direction parallel to the traveling direction of the metal strip 1 is used as the first step of machining. In this first step, it is possible to obtain a processed surface 1a' in which deep and clean grooves are formed parallel to the traveling direction of the metal strip.

In the subsequent second step, the tool roll 6 forms grooves that are inclined in the traveling direction of the metal strip. By appropriately selecting the angle of inclination, it is possible to obtain a processed surface 1b' in which deep and clean grooves are formed.

FIG. 8 shows an apparatus used for surface processing of ordinary high-strength metals. Shallow grooves 51', 51', . . Depending on the properties of the metal strip 1, the feed roll 51 may not be provided with the grooves 51', 51', . . . . 52 is a high-speed rotating tool roll with grooves 5 parallel to the feeding direction.
2', 52', . 53 is a support roll. The tool roll 54 is also provided with a large number of machined grooves 54', 54' that are symmetrically inclined with respect to a plane that passes through the center and is perpendicular to the axis of the tool roll. Molded into a toothed mountain shape 36,
A processed surface 1f on which a large number of 36... are formed is obtained.
The feed roll 51, the support roll 53, and the tool roll 54 are synchronized so that the metal strip 1 can be fed at a constant speed.

Machining groove 5 formed on the circumferential surface of tool roll 54
The protrusion (mountain) between 4' and 54' is the workpiece surface 1e.
The parallel protrusions 35, 35, ... are strongly pressed, and the protrusions 3
5 is a dent 35 due to plastic deformation of the strongly pressed part
a is formed. If the metal strip 1 is relatively soft, the portion adjacent to the recess 35a will bulge out under the influence of strong pressure. That is, in FIG. 8, the quadrangular pyramid-shaped tooth-like chevron formed on the processed surface 1h bulges into the space of the grooved line 37. The auxiliary tool roll 57 is caused to push back this bulged portion. The auxiliary tool roll 57 has machined grooves 57', 57', .
The machined grooves 52' of the machined grooves 52' have the same shape, and the machined grooves 52'
It is necessary that the sawtooth profile of 7' and that of the processed groove 52' be completely aligned in phase. Therefore, when the processed surface 1h passes the auxiliary tool roll 57, the bulging portion of the toothed chevron-shaped surface 35b is pressed by the protrusion of the machining groove 57' of the auxiliary tool roll 57, and the surface 35b becomes almost flat. A processed surface 1f is obtained. If the metal strip 1 is relatively hard, the surface 3
Since the amount of bulge of 5b is small, the auxiliary tool roll 57 can be omitted.

FIG. 9 shows a device used for groove molding of relatively hard metal, and the high-speed rotating tool roll 5 in FIG.
2, a high speed rotating tool roll 62 is used.
The tool roll 62 also has grooves 62', 6 parallel to the feeding direction.
The point where 2'... is provided is the tool roll 52.
(FIG. 8), but is provided with an axially parallel heat relief groove 62''. The heat relief groove serves to dissipate the frictional heat from machining. The tool roll 64 has a A large number of machined grooves 64', 64'' are provided which are symmetrically inclined with respect to a plane perpendicular to the axis. 63 is a support roll, and 64 is a tool roll. 67 is the 8th
This is an auxiliary tool roll having the same function as the auxiliary tool roll 57 illustrated in the figure.

In the present invention, in order to form a toothed chevron shape, a groove parallel to the traveling direction of the metal strip or an inclined groove is formed in a first step, and then a groove formed in a previous step is formed in a second step. By forming grooves in a direction that intersects the grooves formed by the metal strip, deep and clean grooves can be formed, and therefore, a large number of tooth-like chevrons having sharp tips can be formed on the metal strip.

Since the tool roll used in the tooth-like chevron forming process of the present invention is provided with a large number of machined grooves that are symmetrically inclined with respect to a plane perpendicular to the axis, the machined grooves are inclined. Based on this, it is possible to reduce the deformation and collapse of the peaks formed on the metal strip due to the shearing action, and by appropriately selecting the angle of inclination, deep and clean grooves can be formed, and the processed grooves are Due to the symmetrical arrangement, the force components generated in the axial direction of the tool roll are balanced, so the metal strip does not meander and a deep and clean groove can be formed.

Although the present invention has been described above with reference to embodiments, it is of course not limited thereto and may be modified as appropriate without departing from the spirit of the present invention. For example, in the embodiments described above, the machining groove is approximately V-shaped (Fig. 2a, Fig. 7, 8 and 9), it is possible to obtain the same effect as in the case of a V-shaped groove even if a substantially W-shaped groove is used.

[Brief explanation of the drawing]

FIG. 1 is an overall view of the apparatus for carrying out the manufacturing method of the present invention, FIG. 2 a is a partially enlarged view of FIG. 1, FIGS. 2 b and 2 c are explanatory views regarding FIG. Fig. 3 is an enlarged view of part A in Fig. 2a, Fig. 4 is an enlarged view of part B, Fig. 5 is a partially cutaway view of the heat exchanger tube, Fig. 6 is a partially enlarged view of Fig. 5, and Fig. 7 is an enlarged view of part A in Fig. 2a. The figure is a plan view of another embodiment, FIG. 8 is a perspective view of still another embodiment, and FIG.
This figure and FIG. 10 are partial views of still another embodiment. 1... Metal strip plate, 4, 6... Tool roll, 10
~25... Tubular body forming roll, 28... High frequency induction coil, 31, 32... Machining groove, 33, 34...
... Machining groove, 35 ... Projection, 36 ... Toothed chevron, 4
4... Tool roll, 52, 62... High-speed rotation tool roll, 54... Tool roll, 54'... Machining groove, 64... Tool roll, 64'... Machining groove.

Claims (1)

[Claims] 1. A step of forming a large number of tooth-like chevrons on a metal strip by the following steps (i) and (ii), and forming the metal strip with a forming roll so that the tooth-like chevrons become inner walls. A method for producing a heat exchange tubular body, comprising the steps of: forming the C-shaped tubular material into a C-shaped tubular shape; and welding the joining points of both edges of the C-shaped tubular material formed into the C-shaped tubular shape. (i) A tool roll with machining grooves parallel to the direction of travel of the metal strip, or a tool roll with multiple machining grooves symmetrically inclined with respect to a plane passing through the center of the tool roll and perpendicular to its axis. The process of forming deep grooves using a tool roll. (ii) Many grooves are inclined symmetrically with respect to a plane passing through the center of the tool roll and perpendicular to its axis, and the direction of inclination is opposite to the direction of inclination of the machined grooves of the tool roll described in (i) above. A process of forming deep grooves using a tool roll provided with grooves.