JPS59142381A - Heat exchanger - Google Patents

Abstract

PURPOSE:To miniaturize and densify the heat exchanger by a method wherein the heat exchanger is made to be of double cylinder structure comprising a heat transfer cylinder and an outer cylinder, a number of heat transfer fins having communication holes therethrough are attached to the inner and the outer surface of the heat transfer cylinder to thereby provide flow passages for two heat exchanging fluids and non-contact sections serving as communication holes are provided at the annular contact sections of the heat transfer fins and the heat transfer cylinder. CONSTITUTION:A heat transfer cylinder 1 is of double layer structure such that a first fluid side wall 1a and a second fluid side wall 1b are adhered to each other and a leakage detecting groove 2 is formed axially in the adhered wall section so that when any of the side walls 1a and 1b is pierced with a hole, a fluid flows outside to thereby make one notice abnormality. Further, a cylinder 3 is arranged within the heat transfer cylinder 1 with the formation of an annular space 4 between the cylinders and within the space 4 a number of heat transfer fins having communication holes 6 arranged closely in a number of layers at suitable intervals are adhered close to the inner surface of the heat transfer cylinde 1 at the annular contact sections 7. In addition, a part of each of the annular section 7 is cut to provide the non-contact section 7 in the form of a hole serving as a communication hole. Thus, by the provision of the non- contact sections, the fins can be bonded to the heat transfer cylinder with low melting point solder.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a heat exchanger in which a large number of heat transfer fins are provided on the inner and outer surfaces of heat transfer tubes to increase the heat transfer area, and the present invention relates to a heat exchanger that expands the heat transfer area by providing a large number of heat transfer fins on the inner and outer surfaces of heat transfer tubes. It can be applied to refrigerant condensers or evaporators.

Configuration of conventional examples and their problems Conventional water-cooled condensers include double-tube heat exchangers (Figures 5 and 6) and double-wall heat exchangers with parallel water and refrigerant tubes (Figure 7).
, a shell-and-tube heat exchanger (not shown), etc. However, in both cases, the water passage and refrigerant passage are constructed using pipe materials, and the heat transfer area is made denser due to the shape of the pipe material, and the heat exchanger itself is made smaller and lighter to conserve resources. obtain. That was difficult.

Purpose of the Invention The present invention eliminates the above-mentioned drawbacks of the conventional heat exchanger by making the heat transfer surface wide and dense, improving the heat transfer of each fluid, and making the heat exchanger more compact and high-performance. The aim is to obtain this heat exchanger at low cost.

Structure of the Invention In order to achieve this object, the present invention provides a double cylinder of a heat transfer cylinder and an outer cylinder, and provides a large number of heat transfer fins with circulation holes on the inner and outer surfaces of the heat transfer cylinder to transfer heat. In addition to forming a flow path for the two fluids to be exchanged, a non-contact part that also serves as a flow hole is provided in the annular contact part between the heat transfer fin and the heat transfer cylinder.

With this configuration, the heat transfer surface can be configured widely and densely in the heat exchange fluid flow path inside and outside the heat transfer tube, and in front of the boundary layer when the fluid passes through the flow holes of the heat transfer fins and the non-contact part that also serves as the flow hole. The edge effect, the expansion and contraction of the flow as it passes between the heat transfer fins, and the agitation turbulence effect caused by collisions greatly improve heat transfer, making it possible to achieve compactness and high performance.Furthermore, the non-contact part that also serves as a flow hole improves heat transfer. When soldering the heat tube, heat transfer fins, and annular contact part, the flow of molten metal becomes uniform, making it easy to achieve reliable bonding without contact thermal resistance, making it possible to obtain this small, high-performance heat exchanger at low cost. be able to.

Description of examples An embodiment of the present invention will be described below with reference to the drawings.

Reference numeral 1 denotes a hollow cylindrical heat transfer cylinder made of a material with excellent thermal conductivity, and the first fluid side wall 1a and the second fluid side wall 1b are brought into close contact with each other. It has a two-layer structure in which a leak detection groove 2 is provided in the axial direction to notify an abnormality by allowing fluid to flow outside if a hole is formed in any of the side walls 1J1b.

A cylinder 3 is arranged inside the heat transfer cylinder 1, and an annular space 4 is formed. Reference numeral 5 denotes a heat transfer fin having a plurality of communication holes 6 disposed in this annular space 4 in a densely laminated manner at appropriate intervals, and is in close contact with the inner surface of the heat transfer tube 1 at an annular contact portion 7. Reference numeral 8 designates a non-contact portion which also serves as a communication hole and is formed by cutting out a part of the annular contact portion 7 to form a hole.

9 is an annular space 11 formed by the outer cylinder 1o and the heat transfer cylinder 1
It is a heat transfer fin having a large number of communication holes 12 arranged in a dense stack at appropriate intervals, and is in close contact with the outer surface of the heat transfer cylinder 1 at an annular contact portion 13. Reference numeral 14 designates a non-contact portion which also serves as a communication hole and is formed by cutting out a part of the annular contact portion 13 to form a hole. 1
5 is a first fluid inlet hole, 16 is a first fluid outlet hole, 17 is a second fluid inlet hole, and 18 is a second fluid outlet hole.

An important point in terms of performance in the heat exchanger with the above configuration is to reduce the contact thermal resistance at the contact area between the heat transfer cylinder and the heat transfer fins. The structure is designed to completely eliminate contact thermal resistance. At this time, the non-contact portion 8° 14 provided on the heat transfer fin 6.9 and serving also as a communication hole becomes an important requirement. After inserting a large number of heat transfer fins into the inside and outside of the heat transfer tube, the heat transfer tube is heated with the axis in the vertical direction, and when low melting point metal such as solder is supplied from the upper end to each annular contact portion 7, 13, it melts. The solder and other metals circulate along the circumferential direction of the annular contact part, flow down through the non-contact part 8.14 which also serves as a flow hole, and are transmitted to the heat transfer fins laminated in sequence, and are transferred to each annular contact part. It spreads evenly in the circumferential direction of the portions 7.7-13.13, and the annular contact portion and the heat transfer cylinder are completely joined, eliminating contact thermal resistance. Here, it is better to have one non-contact part 8, 14- of each heat transfer fin 5, 9 so that the molten metal such as solder can circulate more easily. This is because if the non-contact part If each fin has two or more force points, it is likely that metal such as molten solder that has sequentially flowed down from above will not flow around the entire circumferential direction of the annular contact area, but will only flow to a portion separated by the non-contact area. , the contact thermal resistance may increase and the performance of the heat exchanger may deteriorate.

By providing a non-contact part in this way, it can be easily joined with metal such as low melting point solder, and by providing one non-contact part for each heat transfer fin, it can be joined more reliably and the contact thermal resistance can be reduced. improved thermal properties can be achieved at low cost.

In addition, as shown in Fig. 4, a heat transfer fin 9' is made by bending a band-shaped material into a ring shape, and a slit-like gap with opposite ends of the heat transfer fin 9' is opened to the entire radial direction of the heat transfer fin. If the non-contact part 19 is used as a hole, not only can processing such as soldering which eliminates contact thermal resistance be performed in the same way, but also the material yield during the production of heat transfer fins can be greatly improved, resulting in a reduction in material costs. Cost reduction can also be achieved.

In the above configuration, a refrigerant (for example, Freon 12 or Freon 22, etc.) is used as the first fluid, water is used as the second fluid, and a case will be described in which the refrigerant condenser is used in a refrigerant condenser that heats water by a heat pump cycle.

The refrigerant, which has been compressed by a compressor (not shown) and becomes a high-temperature gas, flows through the first fluid inlet hole 15 and passes through the flow holes 6 of the heat transfer fins 5 in the annular space 4 and the non-contact portion 8. The refrigerant that sequentially flows toward the outlet side and is condensed and liquefied by heat radiation toward the water side flows out from the first fluid outlet hole 16 .

On the other hand, water also flows into the second fluid inlet hole 17 and the annular space 1
The fluid sequentially flows to the outlet side through the flow holes 12 and non-contact portions 14 of the heat transfer fins 9 in the refrigerant, is heated and heated by the heat of condensation of the refrigerant, and flows out from the second fluid outlet hole 18.

During heat exchange between the refrigerant and water, the heat transfer fins 5.9 are closely attached to the flow paths of the refrigerant and water, so the heat transfer area is high density and wide, and the fins are equipped with flow holes. 6
, 12 are provided to make the fluid flow in a direction substantially perpendicular to the fin surface, and the boundary layer leading edge effect and the heat transfer fin 5 utilize the thin boundary layer portion that occurs when the fluid passes through the communication hole 6° 12.
, 9. In order to greatly improve the heat transfer coefficient due to the agitation turbulence effect due to expansion and contraction of the flow and collision when passing between the non-contact parts 8.14 and the non-contact part 8.14, Small size and high performance can be achieved.

Furthermore, the heat exchanger is installed with the axis of the heat transfer tube 1 in the horizontal direction, and the non-contact part 8 of the heat transfer fin 5 is positioned downward to serve as an oil return hole for lubricating oil for compression that circulates together with the refrigerant. This can promote the return of lubricating oil to the compressor and contribute to improving the reliability of the compressor.

Effects of the Invention As described above, the heat exchanger of the present invention has a double cylinder of a heat transfer cylinder and an outer cylinder, and a large number of heat transfer fins with circulation holes arranged on the inner and outer surfaces of the heat transfer cylinder to transfer heat. Since a flow path for the two fluids to be exchanged is formed and a non-contact part that also serves as a flow hole is provided in the annular contact part between the heat transfer fin and the heat transfer cylinder, the following effects are achieved.

■ Since a large number of heat transfer fins can be provided, the heat transfer area can be expanded, and the heat exchanger can be made smaller and more dense.

■ Low costs can be achieved because multiple heat transfer fin contact areas can be easily joined using low melting point metals such as solder.

(φ The contact thermal resistance of the heat transfer fin contact area can be reliably eliminated by soldering etc., which is effective in improving the performance of the heat exchanger.

0 The reliability of the compressor can be improved because the non-contact part can be used as an oil return hole for lubricating oil for the compressor.

■ Heat transfer fins with flow holes and non-contact parts create a boundary layer leading edge effect and a stirring turbulent flow effect, greatly improving heat transfer coefficient and making it possible to downsize the heat exchanger.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a heat exchanger showing an embodiment of the present invention, Fig. 2 is an external perspective view of a heat transfer fin for the second fluid, and Fig. 3 is a heat transfer fin for the second fluid. FIG. 4 is an external perspective view of another embodiment of the heat transfer fin for the second fluid, and FIG.
The figure is an external perspective view of a conventional double-tube heat exchanger, Figure 6 is a sectional view taken along line BB in Figure 5, and Figure 7 is a part of a conventional double-wall heat exchanger with parallel water tubes and refrigerant tubes. It is a cross-sectional perspective view. 1 heat transfer tube, 5.9 heat transfer fin, 6, 12 communication hole, 7.13- annular contact part, 8, 14 non-contact part, 1o
Outer cylinder. Name of agent: Attorney ±1 Toshio Nakao and 1 other person Figure 1 d Figure 3 Figure 5 392-

Claims (4)

[Claims] (1) A double cylinder consisting of a heat transfer cylinder and an outer cylinder is provided, and a large number of heat transfer fins with communication holes are provided on the inner and outer surfaces of the heat transfer cylinder to form a flow path for two fluids for heat exchange. A heat exchanger that has a non-contact part that also serves as a circulation hole in the annular contact part between the heat transfer fins and the heat transfer cylinder. (2) The heat exchanger according to claim 1, wherein each heat transfer fin is provided with one non-contact portion. (3) The heat exchanger according to claim 1, wherein the non-contact portion is formed by a notch hole on the heat transfer cylinder side of each heat transfer fin. (4) The heat exchanger according to claim 1, wherein the non-contact portion is formed by bending a band-shaped material into an annular shape and forming a slit-like gap at opposite ends thereof.