JP2703665B2 - Heat exchange pipe manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention, in such a heat pump type room air conditioner indoor unit, a method of manufacturing a heat exchange pipes for improving the condensation performance of the refrigerant flowing through the pipe.

[0002]

2. Description of the Related Art FIG. 11 is a perspective view showing a conventional heat exchange pipe. In the figure, reference numeral 1 denotes a pipe, and a plurality of grooves 2 are provided in an inner surface of the pipe 1 in an axial direction. 2 is called a corrugated grooved pipe because it forms a corrugation on the end face of the pipe 1. The pipe 1 is manufactured by forming a groove 2 on a flat base material by pressing or ironing, thereafter rounding the base material into a pipe shape, and further welding a mating surface. By providing the groove 2 in this manner, the area in contact with the refrigerant flowing in the pipe 1 is increased, and the evaporation and condensation performance is promoted, so that the heat transfer coefficient in the pipe can be improved. The specifications of the groove shape of the pipe 1 having such a groove 2 are as shown in FIG. 12, and the outer diameter D, the bottom wall thickness t, the number of the grooves 2, the lead angle β, and the depth of the groove 2 of the pipe 1 are shown in FIG. As for the height H, an appropriate value is given.

[0003]

Since the conventional heat exchange pipe is constructed as described above, it is effective in accelerating the evaporation of the refrigerant flowing through the pipe 1 during cooling. The condensing capacity is about の of the evaporating performance. If the groove 2 is too deep, the film thickness of the refrigerant P accumulated in the groove becomes too small as shown in FIG.
As shown in the figure, there is a problem that the thickness becomes a resistance, hinders the condensation action, and reduces the heat transfer coefficient in the pipe during heating. Thus, the weak point of the heat pump type air conditioner is the heating performance, it is necessary to improve this,
This problem cannot be solved by the conventional corrugated grooved tube.
Further, since the groove 2 is formed in the flat plate material, and then the flat plate is bent and welded into a pipe shape, the groove 2 of the welded portion 3 is crushed, and therefore, the heat transfer coefficient in the pipe is smaller than that of the complete pipe. In the future, if the size of the indoor unit is reduced and the pipes are made thinner, there is a problem that the loss of the welded portion 3 may be fatal.

[0004] The inventions of this, which has been made in order to solve the problems as described above, for the pipe and the pipe structure
After placing the coating material on the substrate using a jig, heat it.
The porous body can be formed in any pattern
The purpose is to obtain a method of manufacturing heat exchange pipes
You.

[0005]

Means for Solving the Problems A method of manufacturing a heat exchange pipes of the invention according to the first aspect, electroless plating treatment to the core material
A coating material is formed by coating to form a coating material.
Put the covering material on the inner surface of the pipe or on the base material for forming this pipe.
Stack using a jig, then heat the coating material
To melt the coating material,
The cattle and the core material are joined to the pipe to
The porous body is formed on the inner surface of the glass.

In the method for manufacturing a heat exchange pipe according to the second aspect of the invention, the electroless plating is performed by electroless nickel plating.
This is the key processing .

[0007]

According to the first and second aspects of the present invention, the porous body is fixed to the pipe by arranging the coating material in a set pattern on the inner surface of the pipe or on the base material for forming the pipe by using a jig. The coating material coated on the peripheral surface of the core material is heated and melted and solidified to enable the coating material.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 6 denotes a pipe used for supplying a coolant, and 4 denotes a plurality of core members made of steel having a diameter of about 50 to 200 μm. The core members 4 are piled up to form a porous body, and the core members 4 and the core member 4 and the pipe 6 are connected by a covering material. FIG. 2 shows a method of forming such a porous body 10. First, a core material 4 having a coating material 5 such as nickel plating applied around the inner surface of a pipe 6 is provided.
As shown in FIG. 2a, a plurality of tubes are stacked and fixed,
Thereafter, the coating material 5 is melted by a heat treatment, and the core material 4 and the core material and the pipe are respectively bonded to each other using the melted coating material 5 as a binder. This allows
A porous body 10 as shown in FIG. 1 is formed on the inner surface of the pipe 6.

Next, the operation will be described. First, the component of the plating layer obtained by the electroless nickel plating treatment is an alloy containing a trace amount of phosphorus as a melting point lowering element in nickel, and a nickel solder (BNi-6Ni: 89%,
P: 11%). Accordingly, the coating material 7 fused by the heat treatment has a bonding strength (2.8 kgf / mm ² ) substantially similar to that of the brazing. Also, a plurality of peaks of the porous body 10 are provided on the inner surface of the pipe 6, and the inside of the pipe 6 is formed by the surface tension of the refrigerant generated in the gaps between the core members 4 constituting each of the porous bodies 10. As shown in FIG. 3, the flowing refrigerant collects in a portion A around the porous body 10. Therefore, the thickness of the refrigerant P is reduced in the other portion B of the inner surface of the pipe 6. As a result, the refrigerant P is easily condensed in a portion where the film thickness is small,
The heat exchange efficiency can be improved by lowering the thermal resistance, and the heat transfer coefficient in the pipe during heating can be improved.

[0010] A method of manufacturing the heat exchange pipe having the porous body will be described. First, as shown in FIG. 2, in this embodiment, copper particles having a particle diameter of 100 μm are used as the core material 4 and electroless nickel plating (nickel: 87 to 93%, phosphorus: 4 to 12%, other 1%). Plating is performed on the core material 4 in a solution at 90 ° C. for 20 minutes to form a nickel plating film serving as the coating material 5 on the core material 4. Thus, the coating material 7 having a nickel plating film of about 3 μm on the copper particles is obtained. FIG. 2 is a diagram schematically showing the coating material 5 relative to the actual dimensional ratio.
Is thickly drawn. Next, a jig made of a material that does not react with nickel plating even in a heated state, that is, a material having poor wettability and a linear expansion coefficient smaller than that of the pipe 6 (here, a stainless steel on which a strong oxide film is formed). 8, that is, the outer diameter equal to the inner diameter of the pipe 6,
In this embodiment, a jig 8 having a plurality of grooves 9 extending in the longitudinal direction is inserted into the pipe 6 as shown in FIG. Then, the coating material 7 is put into the groove 9 of the jig 8 by ultrasonic vibration or the like, and is held by the jig 8 so as not to collapse. This is placed in a brazing furnace in a vacuum (about 10 ⁻³ Torr) atmosphere and heated at 950 ° C. for 30 minutes. By this heat treatment, the coating material 5 of the plating is melted and drawn into the mutual portions of the coating material 7 and the contact portion between the coating material 7 and the inner surface of the pipe 6 due to surface tension, wettability and the like. Core material 4 made of copper as a result of the disappearance of the nickel plating layer
Is exposed as shown in FIG. When the heat treatment is completed, the nickel-plated coating material 5 is solidified and fixed in this state. Thereafter, the jig 8 is pulled out to obtain a heat exchange pipe as a condensing pipe having a plurality of rows of porous bodies 10 as shown in FIG. In the above embodiment,
Although a plurality of porous bodies 10 are provided in the longitudinal direction (axial direction) of the inner surface of the pipe 6, a jig 11 having a plurality of spiral grooves 12 as shown in FIG. 6 can be used. As shown in FIG. 7, a plurality of spiral porous bodies 10 can be formed. The material and outer diameter tolerance of the jig 11 are the same as those of the jig 8. When the jig 11 is pulled out, the jig 11 is pulled out from the pipe 6 while rotating.

FIG. 8 shows another embodiment of the present invention. This is because the molten coating material 5 is placed on the base material 13 of the pipe 6.
As shown in FIG. 8A, a plurality of rod-shaped jigs 14 made of a material which is hardly wetted are placed as shown in FIG. 8A, and the coating material 7 is placed thereon. Heating at a temperature higher than the melting point of the core material 4 and the base material 13;
It is obtained by fusing between the coating materials 7 and between the coating material 7 and the base material 13. After the porous body 10 is formed, the jig 14 is removed from the coating material 7 as shown in FIG. 8B, and the base material 13 is bent into a pipe shape, as shown in FIG. 8C. Then, a heat exchange pipe is formed by welding at the welding portion 6a. Further, by using a grid-like jig (not shown), the ridges of the coating material 7 are discontinuously arranged at a plurality of positions on the base material 13 and heated, whereby the porous body 10 as shown in FIG. Thus, a base material 13 having the same can be obtained. Therefore, if this is processed into a pipe shape, a heat exchange pipe as shown in FIG. 9B is obtained.

In the above embodiment, a method for manufacturing a heat exchange pipe having a porous body 10 on the inner surface where the nickel plating film as the coating material 5 as shown in FIG. As shown in FIG. 10, the core material 4 is made of inexpensive iron powder having a low corrosion resistance and the like, and the coating material 5 is nickel-plated. By controlling the film thickness of the coating material 5 such that the nickel plating film 5 does not disappear from the iron surface of the core material 4, a heat exchange pipe having the porous body 10 excellent in corrosion resistance performance on the inner surface can be obtained. . In the above embodiment, a copper material is used as the material of the core material 4 and the pipe 6, but a metal such as stainless steel, nickel, and perylium steel, an inorganic substance such as glass, and a polymer such as styrene may be used.

[0013]

As described above, according to the first aspect of the present invention, a coating material is formed on a core material by electroless plating.
Form a coating material and apply this coating material to the inner surface of the pipe or
Stacking using a jig on a substrate of the path for type, the
After that, the coating material is heated to dissolve the coating material and melt.
Core material and the core material and pipe
To form a porous body on the inner surface of this pipe.
As a result, the porous body
The pile can be easily and quickly fixed in the pipe.
One that can produce large quantities of heat exchange pipes of this type at low cost
The effect is obtained. In addition, the thickness of the coating
The space of the porous body dissolves because it can be controlled thin
Heat exchange pipe without being buried in the coating material
Has the effect of maintaining good electric heating performance.

According to the second aspect of the present invention, the electroless
Since the plating process was electroless nickel plating,
Connection strength between the core material and the pipe there is effect large.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a heat exchange pipe according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing a procedure for fixing a porous body to a heat exchange pipe according to one embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a refrigerant state in a pipe according to the present invention.

FIG. 4 is a perspective view showing a manufacturing process of the heat exchange pipe of the present invention.

FIG. 5 is a sectional view showing a porous body pattern in a pipe according to the present invention.

FIG. 6 is a perspective view showing another method of manufacturing the heat exchange pipe of the present invention.

FIG. 7 is a sectional view showing a porous pattern of a pipe manufactured by the method shown in FIG. 6;

FIG. 8 is a perspective view showing another method of manufacturing the heat exchange pipe of the present invention.

FIG. 9 is a perspective view showing still another method of manufacturing the heat exchange pipe of the present invention.

FIG. 10 is an end view showing another solidification process for the porous body pipe of the present invention.

FIG. 11 is a perspective view showing a conventional heat exchange pipe.

FIG. 12 is a specification explanatory view showing an appropriate value of a groove shape in a conventional heat exchange pipe.

FIG. 13 is an explanatory diagram showing a state of a conventional refrigerant in a pipe.

[Explanation of symbols]

 4 Core Material 5 Coating Material 6 Pipe 7 Coating Material 8 Jig 10 Porous Body In the drawings, the same reference numerals indicate the same or corresponding parts.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tomomasa Takeshita 3-18-1 Oga, Shizuoka-shi Mitsubishi Electric Corporation Shizuoka Works (56) References JP-A-63-189793 (JP, A) JP-A Sho 60-255981 (JP, A) JP-A-62-106292 (JP, A)

Claims (2)

(57) [Claims] To 1. A plurality of portions of Rupa type inner surface used for the supply of refrigerant, the heat exchange pipes manufacturing method which includes a multi-porous body
The core material is coated with a coating material with a lower melting point by electroless plating.
To form a coating material, and the coating material is
A jig is used on the inner surface of the pipe or on the base material for forming the pipe.
To heat the coating material.
By melting of the covering material,
The core material and the pipe are connected to each other,
Heat exchange pipe characterized by forming a porous body on the surface
Manufacturing method. 2. An electroless plating method comprising the steps of:
The method for producing a heat exchange pipe according to claim 1, wherein the heat treatment is performed by a stick treatment .