JPS583456B2 - Bending method and device for heat exchanger tube with fins - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for bending finned heat exchanger tubes used in heat exchangers, and is particularly applicable to three-dimensional bending of finned heat exchanger tubes. It is suitable.

When aiming to make the heat exchanger more efficient and more compact,
First, generally, in order to increase the amount of heat transferred through the heat exchanger tube, a finned heat exchanger tube in which fins are formed on the outer peripheral surface of the heat exchanger tube is employed, and these are densely arranged.

However, in the past, a method was adopted in which a large number of linear finned heat exchanger tubes were arranged in parallel and the ends of adjacent finned heat exchanger tubes were connected one by one by welding via U-shaped tubes. This resulted in poor work efficiency and high manufacturing costs.

Therefore, as shown in FIG. 1a showing the state of bending of recent finned heat exchanger tubes and FIG. A so-called serpentine bending device has been developed, and has achieved some success, achieving significant improvements in work efficiency and manufacturing costs compared to conventional methods.

However, even in the case of finned heat exchanger tubes bent by such a device, when multiple sets of these are arranged in a stack, the ends of each finned heat exchanger tube are welded to each other via a U-shaped tube. It was necessary to connect.

For this reason, FIG.
As shown in Figure b, it is desired to develop so-called staggered bending in which the finned heat exchanger tubes 1 are successively bent three-dimensionally. According to this staggered bending, the finned heat exchanger tubes 1 can be interconnected. This eliminates the need for any welding work and eliminates all of the conventional drawbacks mentioned above, making it possible to simultaneously achieve dramatic improvements in work efficiency and production costs, as well as high efficiency and compactness as a heat exchanger. be.

By the way, when bending a finned heat exchanger tube, it is necessary to hold the bent part of the finned heat exchanger tube, but in the staggered bending process described above, the finned heat exchanger tube is placed in a three-dimensional spatial arrangement, so this It is not possible to secure an effective holding space for the finned heat exchanger tube, and this is one of the major reasons why staggered bending has not yet been put to practical use.

The present inventors bent the finned heat exchanger tube 1 by, for example, 180 degrees using a bending jig (not shown), and then bent the finned heat exchanger tube 1 as shown in FIG. When the bending jig is removed from the
Focusing on the fact that a wedge-shaped gap 2 is formed when the tube cannot be bent for 80 degrees, the present invention attempts to provide a method and apparatus that can perform three-dimensional so-called staggered bending of a finned heat exchanger tube by utilizing this gap 2. It is something.

The structure of the method for bending a finned heat exchanger tube of the present invention which achieves one of these objects is to prepare a finned heat exchanger tube in which fins of a certain length are radially implanted on the outer circumferential surface as a first iterative step. After bending a predetermined length portion of the finned heat exchanger tube from the reference position by approximately 180 degrees with a constant curvature such that the tips of the fins touch each other, the bent portion is set as a new reference position and the predetermined length is bent from the reference position. The length part is bent at about 180 degrees at the constant curvature with the bending direction shifted by about 60 degrees with respect to the bending direction of the first iterative step as a second iterative step, and the first iterative step and the second iterative step The structure of the finned heat exchanger tube bending device of the present invention, which is characterized in that the bending process is repeated alternately, and which achieves the other object, is characterized in that the finned heat exchanger tube is A winding strut is installed that extends in a direction perpendicular to the longitudinal direction of this mandrel, and approximately 180 mm around this winding strut is installed.
A hemorrhoid arm that reciprocates and rotates in a range of degrees is attached to the wrapping support, and the support arm is inserted between adjacent fins formed on the outer peripheral surface of the finned heat exchanger tube protruding from the tip of the mandrel. A comb-shaped gripping member that bends a portion of the finned heat exchanger tube protruding from the tip of the mandrel around the supporting column by driving rotation of the mandrel is attached to the support arm so as to be movable towards and away from the finned heat exchanger tube. attaching a presser block that fits into the wrapping strut and cooperates with the wrapping strut to clamp the finned heat exchanger tube to the support arm so that it can be freely fitted into and removed from the wrapping strut in the longitudinal direction; The present invention is characterized in that a turning mechanism is provided for attaching the finned heat exchanger tube and rotating the finned heat exchanger tube back and forth about 60 degrees about the mandrel.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings from FIG. 4 onwards.

As shown in FIG. 4a showing the schematic front shape of this embodiment and FIG. The winding support arm 11 is provided with a support arm 13 that horizontally reciprocates within a range of about 180 degrees by a drive mechanism (not shown) about the winding support 11 as a center.
is installed.

On the other hand, the finned heat exchanger tube 14 is inserted and the tip portion 15
A rod-shaped mandrel 15 whose length a reaches to the side of the upper end of the winding support 11 is positioned in a horizontal direction perpendicular to the longitudinal direction (vertical up-down direction) of the winding support 11, and below this mandrel 15. There is a curved tub-shaped guide support plate 16 that comes into contact with the lower end of the fins 14a of the finned heat exchanger tube 14 fed toward the tip 15a of the mandrel 15 and guides the movement of the finned heat exchanger tube 14. is provided.

The presser block 17 wraps around the heat exchanger tube 14b of the finned heat exchanger tube 14 that has reached the tip 15a of the mandrel 15, and works together with the struts 11 to clamp and hold it from above and below.
The presser block horizontally moving cylinder 19 is supported at the tip of a piston rod 19a of a presser block horizontally moving cylinder 19 via an upwardly curved arm 18 to avoid damage to the presser block horizontally moving cylinder 19. The presser block 17 is attached to the tip of the piston rod 20a of the presser block lifting cylinder 20, and the presser block 17 is moved around the winding column 11 by the operation of the presser block horizontal movement cylinder 19 and the presser block lifting cylinder 20.
It is possible to move towards and away from the enemy.

As shown in FIG. 5, which shows the view from the ■-■ arrow in FIG. In order to accurately position the presser block 17 with respect to the wrapping support 11, a tapered fitting protrusion 11a protruding from the upper end of the wrapping support 11 is fitted. A fitting recess 17a is carved in the lower end surface of this presser block 17.

Furthermore, as will be described later, this presser block 17 is inserted into the gap created when the finned heat exchanger tube 14 is bent (see Fig. 3), so the upper and lower wall thicknesses should be reduced as much as possible to avoid damage to the fins 14a. Desirably thin.

In this embodiment, gripping members 21 and 22, which are inserted between adjacent fins 14a of the finned heat exchanger tube 14 protruding from the tip 15a of the mandrel 15 and have a comb-like shape, are arranged in the vertical direction and the horizontal direction, respectively. The elevating and lowering gripping member 21 is movable toward and away from the finned heat exchanger tube 14 and moves up and down, and is attached to the tip of a piston rod 23a of a gripping member elevating cylinder 23 fixed on the support arm 13. A horizontally movable gripping member 22 that moves horizontally is attached to the tip of a piston rod 25a of a gripping member horizontally movable cylinder 25 fixed to the support arm 13 via a bracket 24 so as to be parallel to the presser block horizontally movable cylinder 19. .

In addition, as shown in FIG. 6, which shows the positional relationship between the heat transfer tube 14b in FIG. The portion is formed in an arc shape with a curvature corresponding to the outer diameter of the heat exchanger tube 14b, thereby making it possible to transmit the rotational force of the support arm 13 to the finned heat exchanger tube 14 without waste.

Although not shown, a turning mechanism is provided on the side of the mandrel 15, which can grip the finned heat exchanger tube 14 and turn it up to a maximum of 180 degrees around the mandrel 15, as shown in FIG. 4b. Inside, reference numeral 26 denotes a variable angle support plate which holds the finned heat exchanger tube 14 rotated by the rotation mechanism and has a function of regulating the rotation angle.

Next, the method of three-dimensional bending (zigzag bending) of the finned heat exchanger tube 14 using the apparatus of this embodiment will be explained step by step with reference to FIG. 7 showing the work procedure. The heat tube 14 is connected to the tip 15a of the mandrel 15.
The cylinder for horizontal movement of the presser block 19 and the cylinder for lifting and lowering the presser block 20 are actuated, and the cylinder for lifting and lowering the gripping member 23 and the cylinder for horizontal movement of the gripping member 25 are actuated.
and the presser block 17 to press and support the heat exchanger tube 14b of the finned heat exchanger tube 14 from above and below, and also to hold the elevating gripping member 21 and the horizontally movable gripping member 22 into the finned heat exchanger tube protruding from the tip of the mandrel 15. It is inserted between adjacent fins 14a of the heat tube 14 (see FIGS. 7A and 7A).

Thereafter, when the support arm 13 is wrapped and rotated 180 degrees around the strut 11, the finned heat exchanger tube 14 is bent 180 degrees around the wrapped strut 11.
When the support arm 13 reverses and returns to its original position,
Due to the inherent elastic force of the finned heat exchanger tube 14, a wedge-shaped gap 27 is formed in the finned heat exchanger tube 14 without being bent 180 degrees.

Note that during this operation, the tip 15 of the mandrel 15
a functions to prevent the bent portions of the heat exchanger tubes 14b from flattening.

After this operation is completed, the cylinder 19 for horizontal movement of the presser block and the cylinder 20 for lifting the presser block are operated, and the cylinder 23 for lifting and lowering the gripping member and the cylinder 25 for horizontal movement of the gripping member are activated, and the presser block 17 and the lifting and lowering support member 21 are operated. and horizontally movable gripping member 22 to the finned heat exchanger tube 1.
4 (see Figure 7B, b).

Next, the finned heat exchanger tube 14 is attached to the tip 1 of the mandrel 15.
5a again to protrude a certain amount (Fig. 7C)
, c) and the mandrel 15 using a rotating mechanism.
In this example, the center is rotated by 60 degrees (Fig. 7D,
d), the presser block horizontal movement cylinder 19 and the presser block lifting cylinder 20 are operated again, and the gripping member lifting cylinder 23 and the gripping member horizontal movement cylinder 25 are actuated to obtain the case shown in FIGS. 7A and a. Similarly, the holding block 17 is fitted to the wrapping support 11 to support the heat exchanger tube 14b under pressure from above and below, and the lifting gripping member 2
1 and the horizontally movable gripping member 22 are inserted between the adjacent fins 14a of the finned heat exchanger tube 14 (see FIGS. 7E and 7E). Since it is inserted, the fin 14a
It is possible to minimize damage to

Thereafter, as in the case shown in FIGS. 7B and 7B, the support arm 13 is rotated 180 degrees, and the finned heat exchanger tube 14 is wrapped around the support arm 11 and bent around the support 11 (see FIGS. 7F and F).
After repeating the above-mentioned operation, an external force for removing the gap 27 is applied to the finned heat exchanger tube 14, and as shown in FIG.
It is possible to obtain a finned heat exchanger tube subjected to three-dimensional bending (staggered bending) as shown in b.

Further, if the elastic force of the finned heat exchanger tube is weak, an appropriate gap will not be formed, so it is preferable to obtain an appropriate gap by adjusting the amount of bending of the finned heat exchanger tube.

As described above, according to the method and apparatus for bending a finned heat exchanger tube of the present invention, the finned heat exchanger tube is supported under pressure using the gap created when the finned heat exchanger tube is bent in order to avoid damage to the fins. As a result, it becomes possible to perform three-dimensional bending (zigzag bending) of the finned heat exchanger tube, which was previously impossible, and it is possible to achieve high efficiency and compactness of the heat exchanger at low cost.

[Brief explanation of the drawing]

FIG. 1a is a plan view showing the finned heat exchanger tube in a plane bent state, FIG. 1b is a view taken along the line B-B, FIG. Figure 2b is a view taken along the line B-B, and Figure 3 shows the finned heat exchanger tube at 180 mm.
FIG. 3 is a plan view of the finned heat exchanger tube showing that a gap is formed due to the elasticity of the finned heat exchanger tube when it is bent. FIG. 4a is a front view schematically showing an embodiment of the bending device for finned heat exchanger tubes according to the present invention, FIG. 4b is a right side view thereof, and FIG. Fig. 6 is a partial extracted view showing the shape of the elevating gripping member and the horizontally movable gripping member in Fig. 4b, and Figs. Work process diagrams showing the procedure for three-dimensional bending of heat pipes, Figures I a to f are respectively No. 7
A-A in Figures A-F. , B-B, C-C,
It is a DD, EE, FF arrow view. In the drawings, 11... Wrapping strut, 11a... Fitting convex portion of wrapping strut, 13... Support arm, 14...
Fined heat exchanger tube, 15... mandrel, 15a...
Tip of mandrel, 17... Presser block, 17a
... Fitting recess of presser block, 19... Cylinder for horizontal movement of presser block, 20... Cylinder for lifting and lowering presser block, 21... Member for lifting/lowering gripping, 22... Horizontal movement gripping member, 23.・Cylinder for lifting and lowering the gripping member, 25...
- Cylinder for horizontal movement of gripping member, 27...This is a gap formed in the finned heat exchanger tube.

Claims (1)

[Claims] 1. A finned heat exchanger tube in which fins of a certain length are radially planted on the outer circumferential surface is used as a first iterative step to remove a portion of a predetermined length from a reference position set in advance on the finned heat exchanger tube. Approximately 18 mm with a constant curvature such that the tips of the fins touch each other.
After bending by 0 degrees, this bent part is set as a new reference position, and a portion of a predetermined length from the reference position is set as a second repetition process, which is approximately 60 degrees with respect to the bending direction of the first repetition process.
Approximately 18 degrees at the constant curvature with the bending direction shifted
A method for bending a finned heat exchanger tube, characterized in that the first repeating step and the second repeating step are alternately repeated. 2. A winding support that extends perpendicular to the longitudinal direction of the mandrel is installed on the side of the tip of the mandrel into which the finned heat exchanger tube is inserted, and the winding support is rotated reciprocatingly within a range of approximately 180 degrees around the winding support. A supporting arm is attached to the winding strut, and is inserted between adjacent fins formed on the outer circumferential surface of the finned heat exchanger tube protruding from the tip of the mandrel, and is inserted between adjacent fins formed on the outer peripheral surface of the finned heat exchanger tube protruding from the tip of the mandrel, and the tip of the mandrel is inserted by driving rotation of the support arm. A comb-shaped holding member for bending a portion of the finned heat exchanger tube protruding from the finned heat exchanger tube around the wrapping support is attached to the support arm so as to be movable toward and away from the finned heat exchanger tube, and is fitted with the wrapping support. A presser block is attached to the support arm so as to be able to be fitted into and removed from the wrapping support in the longitudinal direction thereof, and also works with the wrapping support to sandwich the finned heat exchanger tube. A bending device for a finned heat exchanger tube, comprising a turning mechanism for reciprocating the heat tube by about 60 degrees around the mandrel.