JPS5926238B2 - Manufacturing method of heat exchanger tube with fins - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a finned heat transfer tube particularly suitable for a mist cooling heat exchanger that exchanges heat between an airflow (mist airflow) containing fine water droplets (mist) and another heat medium.

In a mist cooling heat exchanger, wetting the entire surface area of the smooth tube or bifin tube with the mist liquid improves heat transfer performance.

Conventionally, the heat medium inside the tube is cooled or condensed using a mist air stream.

Heat exchanger tubes such as smooth tubes and bifin tubes are used in so-called mist cooling heat exchangers.

In addition, as an improvement, the surface of one circular tube. A type in which fine grooves are provided on the side surface of the fin has also been proposed.

However, when a smooth tube is placed perpendicular to the mist airflow, the front surface of the tube is wetted by the mist, but the rear surface is not.

In the bifin tube as shown in FIG. 1, the heat exchanger tube 1. Although a small portion of the front and side surfaces of the fin 2 get wet, the back half does not get wet.

When the fins 2 are provided with circumferential grooves and intersecting grooves, the wettability of the fin side surfaces is improved.

However, there are the following problems in the process of manufacturing the fin tube having the fine grooves.

That is, when wrapping the fins 2 around the heat exchanger tube 1, the strip fins 2 must be stretched and bent in order to improve contact between the strip fins 2 and the heat exchanger tube 1 and to improve heat transfer.

Therefore, the outer circumferential side of the band-shaped plate fin 2 is strongly stretched, cuts are made from the grooves in the outer circumferential part, and eventually the band-shaped plate fin 2 is cut, making it impossible to manufacture it successfully.

An object of the present invention is to provide a manufacturing method for efficiently manufacturing a finned heat transfer tube with good wettability.

In the present invention, one edge of a belt-shaped flat plate is processed without grooves, and this flat belt-shaped plate is wound around a heat exchanger tube while applying tension to the flat belt-shaped plate, with the edge without the groove becoming the outer periphery of the fin. It is characterized by

Embodiments of the present invention will be described below with reference to FIGS. 3, 4, and 5.

FIG. 3 shows a strip-like flat plate used as a fin in the method of the present invention.

Fine intersecting grooves 4 are formed in the belt-like flat plate 3 except for one edge 3e side.

The fine grooves 4 are grooved on both sides of the strip fin 3 by knurling.

Note that the fine grooves 4 may be provided only on one side of the band-shaped flat plate 3.

While applying a tensile force to such a belt-shaped flat plate 3.

The heat exchanger tube 1 is wound around the heat exchanger tube 1 so that the edge 3e where the groove 4 is not provided becomes the outer periphery to produce a finned heat exchanger tube.

Hereinafter, the belt-shaped flat plate 3 wound around the heat exchanger tube 1 will be simply referred to as a fin 3.

Since the fins 3 are wrapped around the heat exchanger tube 1 while applying tension, there is no need to specifically fix the two, but in order to reduce the contact thermal resistance, the band-shaped flat plate 3 and the heat exchanger tube 1 are brazed or soldered. , or may be joined by fixing means such as tube expansion.

The finned heat exchanger tube manufactured in this manner is shown in FIGS. 4 and 5.

In this finned heat exchanger tube, grooves 4 are not provided on the outer periphery of the fins 3, but fine intersecting grooves 4 are provided in other portions.

Further, the fins 3 are wound around the heat exchanger tube 1 in a spiral manner.

This finned heat exchanger tube is used in a state where it is installed substantially directly and horizontally with respect to a gas flow containing mist (mist air flow).

Next, the operation of the finned heat exchanger tube according to the present invention will be explained.

First of all, the mist in the mist airflow starts with the heat exchanger tube 1 and the fins 3.
Attach to the front of the

As the amount of mist adhering to the front surface increases, the side surfaces of the fins 3 gradually become wet from the outer periphery of the front surface.

The mist then travels through the intersecting grooves 4 and gradually moves toward the inner periphery (
Flows toward heat transfer tube 1).

Also wet the inner circumferential side of fin 3 with mist.

A medium having a temperature difference from the mist airflow, such as refrigerant vapor, flows inside the heat exchanger tube 1, and the refrigerant vapor is cooled by the mist airflow and liquefied.

Although the finned heat exchanger tube of the embodiment of the invention does not have grooves formed on the outer periphery of the fins, the outer periphery can be wetted with mist even without grooves, so heat transfer is equivalent to that of fins with grooves on the entire surface (side surface). It has performance.

Moreover, the fins are shaped so that they do not break, making it an easy-to-manufacture heat transfer tube.

In the method of the embodiment of the present invention, a flat band-like plate without grooves on at least one edge is wound around a heat exchanger tube while applying tension so that at least the edge without grooves becomes the outer periphery. There is no breakage in the flat strip due to expansion and contraction when tension is applied or when winding (the outer circumferential edge of the strip flat plate 3 stretches and the inner circumferential edge contracts).

Therefore, the finned heat exchanger tube can be manufactured efficiently.

In addition, there is no need to worry about the belt-shaped flat plate being cut inside when wrapped around it.
There is no need to increase the thickness of the flat belt-shaped plate that becomes the fin to prevent the flat plate from breaking, or to reduce the tensile force applied to the flat plate to prevent breakage.

That is, a thin flat plate is used as the fin material, and the fin material is wound with a large tensile force.

This is because the winding of the fins is effective in maintaining a high speed, and the adhesion of the fins to the heat exchanger tube is increased.

As described above, according to the present invention, an efficient manufacturing method can be provided.

[Brief explanation of drawings]

Fig. 1 is a front sectional view of a conventional bifin tube, Fig. 2 is a sectional view taken along the line ■-■ of Fig. 1, Figs. A front view of the fins, and FIG. 4 is a front sectional view of the finned heat exchanger tube. FIG. 5 is a sectional view taken along the line v--■ in FIG. 4. 1... Heat exchanger tube, 3... Fin, 4...
...Fine grooves.

Claims (1)

[Claims] 1. Fine grooves on at least one surface of a flat strip. The fins are formed on the part of the flat belt-shaped plate excluding one edge, and then, while applying tension to the flat belt-shaped plate, the flat belt is wrapped around the outer periphery of the heat transfer tube so that the edge without grooves becomes the outer periphery. A method for manufacturing a heat exchanger tube with fins, the method comprising manufacturing a heat tube.