JP2000105090A - Plate type heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a brazing plate type heat exchanger which dispenses with coating the inner surface of a copper tube inserting nozzle with flux for removing oxides by copper cladding a copper tube inserting nozzle made of stainless steel. SOLUTION: The brazing plate type heat exchanger 1 dispenses with gasket by laminating a large number of heat transfer plates 1a applied with brazing metal between body frames 1b, 1c on the opposite sides and fusion jointing the periphery of the heat transfer plates 1a and the peripheral part of a passage hole simultaneously at high temperature under vacuum. Four copper tube inserting nozzles 2 are brazed simultaneously to the body frame 1b and the inner face 3 of the copper tube inserting nozzle 2 is subjected to copper cladding 6. According to the method, brazing with a copper tube 4 is improved and the need of flux is eliminated by using copper phosphorus brazing metal 7. Inner face 3 of the copper tube inserting nozzle 2 is copper clad 6 by copper plating the entire surface of the nozzle before it is brazed to the body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a brazing plate type heat exchanger which is permanently joined with a copper brazing or nickel brazing material, and more particularly, to a fluid inlet / outlet of a brazing plate type heat exchanger. To improve copper tube insertion nozzles.

[0002]

2. Description of the Related Art What is a brazing plate heat exchanger?
A number of heat transfer plates coated with brazing material are stacked between the main body frames on both sides, and the periphery of the heat transfer plate and the periphery of the passage hole formed in the heat transfer plate, and possibly the entire heat transfer surface, are heated to a high temperature. A plate-type heat exchanger characterized by simultaneous fusion bonding under vacuum and bonding in one step, eliminating the need for gaskets.

Conventional brazing plate type heat exchanger 1
As shown in FIG. 3 (A), the copper pipe insertion nozzle 2 is made of the same stainless steel as the main body. Must be applied to the inner surface 3 of the nozzle. After the flux application, generally, as shown in FIG.
The copper tube 4 is brazed to the copper tube insertion nozzle 2 using (silver solder 5).

[0004]

The problem to be solved here is as follows.
As a flux used for removing oxides, a fluoride-based flux is often used, and in order to prevent corrosion due to residual flux, it is necessary to wash and remove the residual flux after brazing.

The present invention eliminates the need to apply a flux for removing oxide to the inner surface of a copper tube insertion nozzle, and eliminates the need for cleaning the inner surface of the nozzle for removing residual flux after brazing a copper tube. The purpose of the present invention is to provide a heat exchanger.

[0006]

In order to achieve the above object, the present invention is characterized in that a stainless steel copper pipe insertion nozzle is coated with copper in a brazing plate type heat exchanger which is permanently joined. Is what you do.

According to the present invention, a copper coating is applied to the inner surface of a copper tube insertion nozzle to which a flux has been applied, so that the copper tube can be brazed by BCuP (phosphor copper brazing). ) Can be used, and no flux is required.

In order to coat the copper pipe insertion nozzle with copper, copper plating is performed, or a film is formed by placing a copper ring, a copper foil, or the like.

Further, when the copper coating is formed simultaneously with the brazing of the main body, the surface of the copper pipe insertion nozzle should be 12.5 μm Ry.
With the rough surface as described above, it is possible to prevent the molten copper from flowing down and to reliably form the copper film.

[0010]

FIG. 1A is a front view of a brazing plate heat exchanger according to the present invention, and FIG. 1B is a side view thereof.

The brazing plate type heat exchanger is shown in FIG.
(A) and (B), a large number of heat transfer plates 1a coated with a brazing material are stacked and disposed between the main body frames 1b and 1c on both sides, and are arranged around the heat transfer plate 1a and on the heat transfer plate 1a. The periphery of the passage hole (not shown) formed with the opening and, if necessary, the entire heat transfer surface are simultaneously melt-bonded under high temperature and vacuum, and the bonding is performed in one step, thereby eliminating the need for a gasket. Four copper pipe insertion nozzles 2 serving as fluid ports are simultaneously brazed to the main body frame 1b on the front side. Each heat transfer plate 1a, the main body frames 1b and 1c on both sides, and the copper pipe insertion nozzle 2 are made of stainless steel. The copper pipe insertion nozzle 2 may be joined to the main body frame 1c.

According to the present invention, the inner surface 3 of the copper pipe insertion nozzle 2 is provided.
Then, as shown in FIG. 2A, a copper coating 6 is applied. In this way, the inner surface 3 of the copper pipe insertion nozzle 2
Is performed, as shown in FIG.
Can be obtained by brazing copper-copper, and BCuP (phosphorus copper brazing) can be used as the brazing material 7, so that no flux is required.

Copper coating 6 on inner surface 3 of copper pipe insertion nozzle 2
May be applied after the brazing of the brazing plate type heat exchanger body is completed, but it is also possible to partially coat the brazing plate or braze the entire nozzle (not shown) before brazing the body, As shown in FIGS. 2 (C) and 2 (D), a ring-shaped copper braze 6a is placed on the inner surface 3 of the copper pipe insertion nozzle 2, or a copper foil roll 6b is placed thereon, and the main body is brazed. At the same time, the copper coating 6 can be formed.

However, when the copper coating 6 is formed simultaneously with the brazing of the main body, the inner surface 3 of the copper pipe insertion nozzle 2 is 12.5 μm.
It has been found that when the surface roughness is less than mRy, copper flows down and a copper film is not formed, and to prevent copper flow, as shown in FIG. The inner surface 3 needs to be a rough surface 3a, specifically, 25 μm Ry.
Surface roughness of about 50 μm Ry is appropriate.

In addition, as shown in FIG. 2F, in the case where the copper plating 6c is provided on the entire surface of the copper pipe insertion nozzle 2 facing downward, the copper of the portion other than the inner surface of the nozzle whose surface is roughened flows down, The copper tube 4 may not be able to enter due to the solder pool 6d. In this case, as shown in FIG. 2 (G), it is improved by making the entire surface of the copper pipe insertion nozzle 2 have a surface roughness of about 25 μm Ry to 50 μm Ry.

[0016]

According to the present invention, a copper coating is applied to the inner surface of a conventional copper pipe insertion nozzle to which a flux has been applied.
P (phosphorus copper brazing) can be used, and no flux is required.

In order to coat the copper pipe insertion nozzle with copper, copper plating is applied, or a film is formed by placing a copper ring, copper foil, or the like.

When the copper coating is formed simultaneously with the brazing of the main body, the surface of the copper pipe insertion nozzle is 12.5 μm Ry.
With the rough surface as described above, it is possible to prevent the molten copper from flowing down and to reliably form the copper film.

[Brief description of the drawings]

FIG. 1A is a front view of a brazing plate heat exchanger according to the present invention, and FIG. 1B is a side view thereof.

2A is an enlarged cross-sectional view of a copper pipe insertion nozzle according to the present invention before copper pipe insertion, and FIG. 2B is an enlarged cross-sectional view of the copper pipe insertion nozzle according to the present invention at the time of brazing after copper pipe insertion. Figure,
(C) and (D) are enlarged sectional views showing different embodiments when copper coating is applied to the inner surface of the copper pipe insertion nozzle, and (E) is molten when copper coating is applied to the inner surface of the copper pipe insertion nozzle. (F) Enlarged cross-sectional view showing measures to prevent the falling of copper
Is an enlarged cross-sectional view for explaining a problem that a copper brazing occurs due to a flow-down of molten copper when copper coating is performed on the inner surface of a copper pipe insertion nozzle facing downward, and FIG. FIG.

FIG. 3A is an enlarged cross-sectional view of a conventional copper pipe insertion nozzle before copper pipe insertion, and FIG. 3B is an enlarged cross-sectional view of a conventional copper pipe insertion nozzle during brazing after copper pipe insertion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Brazing plate type heat exchanger 1a Heat transfer plate 1b, 1c Main body frame 2 Copper pipe insertion nozzle 3 Nozzle inner surface 3a Rough surface 4 Copper tube 5 Silver brazing material 6 Copper coating 6a Ring-shaped copper brazing material 6b Winding copper foil Brazed brazing material 6c copper plating 7 brazing material (phosphorus copper brazing)

Claims (4)

[Claims] 1. A plate type heat exchanger in which a brazing plate type heat exchanger to be permanently bonded is provided with a copper coating on a stainless steel copper tube insertion nozzle. 2. The plate heat exchanger according to claim 1, wherein the copper pipe insertion nozzle is plated with copper. 3. The plate heat exchanger according to claim 1, wherein the film is formed by placing a copper ring, a copper foil, or the like. 4. The surface of the copper tube insertion nozzle is 12.5 μm R
The plate type heat exchanger according to any one of claims 1 to 3, wherein the plate type heat exchanger has a rough surface of y or more.