JPH10230383A - Method for preventing oxidation of inside surface in brazing metallic tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for preventing oxidation of the inside surface in the case of brazing a metallic tube requiring prevention of oxidation of the inside surface at the time of brazing. SOLUTION: At the time of brazing a metallic tube 1 and the joining object 2 with the inside surface of a part 7 to be brazed kept contact with antioxidizing gas, a baffle member 3 with a smaller diameter than the inner diameter of the tube is incorporated near the interior of part 7, and at the same time antioxidizing gas is made to flow-in from the outside of the circumferential outer surface along the inside surface of the tube 1, and thus the inside surface of the part 7 is kept contact with the antioxidizing gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxidation preventing method for preventing the inner surface of a metal pipe from being oxidized during brazing.

[0002]

2. Description of the Related Art For example, in a compressor used in an air conditioner system or the like, a main body called a shell is brazed with a suction pipe made of a metal such as copper. When the inner surface of the suction pipe is oxidized to form an oxide film, the refrigerant gas, which is a refrigerant, is clogged with time. Therefore, it is necessary to prevent oxidation of the inner surface when brazing the suction pipe.

[0003] The prevention of oxidation of the inner surface during brazing as described above is performed by introducing an antioxidant gas into the suction pipe and bringing the inner surface of the brazing portion into contact with the antioxidant gas. Conventionally, the antioxidant gas is allowed to flow into the entire inside of the suction pipe as it is, so that the amount of gas increases and waste occurs. Moreover, in order to ensure that the inner surface of the brazing portion is in contact with the gas, the entire inside of the suction pipe must be filled with the gas. Therefore, the opening on the side opposite to the gas supply side of the suction pipe so that the gas does not escape. Work must be performed by closing the end with a lid, it takes time until brazing,
The efficiency was extremely poor.

The present invention has been made in view of such a technical background, and provides an internal oxidation preventing method for brazing a metal pipe that needs to prevent internal oxidation during brazing. The purpose is to:

[0005]

In order to achieve the above object, the present invention provides a metal pipe for brazing a metal pipe to an object to be brazed while contacting an inner surface of a brazing portion with an antioxidant gas. In the method for preventing oxidation of the inner surface during brazing, a baffle member having an outer diameter smaller than the inner diameter of the pipe is disposed near the inside of the brazed portion, and an antioxidant gas is supplied from the outer surface of the peripheral surface of the baffle member. By flowing along the inner surface of the pipe, the inner surface of the brazed portion is brought into contact with an antioxidant gas.

Accordingly, it is not necessary to fill the entire pipe with gas, and even if the amount of antioxidant gas is small,
The gas is reliably guided to the inner surface of the brazing portion, and oxidation of the inner surface is effectively prevented.

[0007]

Next, an embodiment of the present invention will be described. In this embodiment, a case will be described in which a suction pipe of a compressor is high-frequency brazed.

In FIGS. 4 and 5, (1) is a copper L-shaped suction pipe as a metal pipe, and (2) is a bowl-shaped shell as an object to be joined, which constitutes a part of the main body of the compressor. An outwardly projecting connecting short pipe (21) is provided at the center of the top of the shell (2), and the distal end of the connecting short pipe (21) is expanded to a large diameter so that the suction pipe can be inserted. An insertion portion (22) is formed, and an outwardly conical flared portion (2) is formed at the tip of the insertion portion (22).
3) is formed.

The suction pipe (1) is a passage through which a refrigerant such as chlorofluorocarbon gas flows. If an oxide film is formed on the inner surface of the suction pipe (1), the refrigerant may become clogged. It is said that.

In the present invention, as shown in FIGS. 1 and 2, a disk-shaped baffle member (3) is used as a baffle plate when brazing. The outer diameter of the baffle member (3) is set smaller than the inner diameter of the suction pipe (1),
It has a small diameter neck (31) at the center of its lower surface. 2 and 3, reference numeral (4) denotes a gas supply member for supplying an antioxidant gas. The gas supply member (4) has a cylindrical shape smaller than the inner diameter of the suction pipe (1), and a hollow gas passage (41) is formed in the axial direction from the lower end to the vicinity of the upper end, and the gas passage (41) is formed. A gas reservoir (42) is formed in communication with the upper part of ()). A plurality of gas outlets (43) penetrating vertically through the upper wall of the gas supply member (4) are formed in the circumferential direction. Further, at the lower end of the gas supply member (4),
The gas pipe connecting cylinder (4) communicating with the gas passage (41)
4) is formed, and a cylindrical socket portion (45) for removably inserting and mounting the neck portion (31) of the baffle member (3) is provided at the center of the upper surface of the gas supply member (4).
Are formed. In this way, by configuring the baffle member (3) to be detachable from the gas supply member (4), even if the inner diameter of the suction pipe (1) is different, only the baffle member (3) having a different size can be replaced. The suction pipe (1) of various sizes can be efficiently used.

The brazing of the suction pipe (1) is performed as follows. That is, first, one end of the suction pipe (1) is inserted into the insertion part (22) of the connecting short pipe (21) of the shell (2), and the ring-shaped brazing material (5) is flared at the tip of the insertion part ( 23), and a ring-shaped or C-shaped or horseshoe-shaped induction coil (6) of the high-frequency induction heating device is connected to the brazing portion (7) of the suction pipe (1) and the connection short pipe (2). Place around.

On the other hand, the neck portion (31) of the baffle member (3) is inserted and fixed in the upper end socket portion (45) of the gas supply member (4), and the gas pipe connection tube at the lower end of the gas supply member (4). Connect the gas pipe (8) to (44). Then, the baffle member (3) and the gas supply member (4) are connected from below the shell (2) so that the baffle member (3) is located slightly below the brazing portion (7). ) Furthermore, while inserting it into the suction pipe (1),
The baffle member (3) and the gas supply member (4) are fixed such that a gap (9) is created between the baffle member (3) and the inner surface of the suction pipe (1).

Next, an antioxidant gas is introduced into the gas supply member (4) through the gas pipe (8). As the antioxidant gas, N2 gas, chlorofluorocarbon gas, H2 gas or the like can be suitably used. The antioxidant gas introduced into the gas supply member (4) rises in the gas passage (41) in the supply member (4) by the gas supply pressure, as indicated by an arrow in FIG. (42), where it spreads and is ejected upward through a plurality of gas outlets (43) existing in the circumferential direction.

Since the baffle member (3) exists above the gas supply member (4), the gas outlet (4)
The antioxidant gas ejected upward from 3) collides with the baffle member (3) and is prevented from traveling upward, and flows radially outward along the lower surface of the baffle member (3). Then, it rises through the gap (9) between the peripheral surface of the baffle member (3) and the inner surface of the suction pipe (1), rises as it is along the inner surface of the suction pipe (1), and is eventually brazed. After reaching the inner surface of (7), the air inside the inner surface is replaced with the antioxidant gas, and this state is maintained by the continuous supply of the gas.

In this state, when a high-frequency current is applied to the induction coil (6), the suction pipe (1) and the connecting short pipe (21) of the shell (2) are heated at the brazing part (7) and the temperature thereof is increased. Rapidly rises, the brazing material (5) is melted, and the suction pipe (1) and the connecting short pipe (21) are integrated by brazing. Since the inner surface of the suction pipe (1) is in contact with the antioxidant gas at the brazed portion (7), oxidation of the brazed portion inner surface due to a rise in temperature of the brazed portion (7) is prevented. Is done.

After the brazing, when the temperature of the brazing portion is sufficiently lowered, the supply of the antioxidant gas is stopped.

The size, shape and number of the gas outlets (43) in the gas supply member (4), the size of the gap (9) between the baffle member (3) and the suction pipe (1), etc. What is necessary is just to set suitably so that it may become most efficient according to the magnitude of gas supply pressure.

In the above embodiment, brazing is performed by the high-frequency induction heating method. However, the present invention can be applied to the case of performing gas brazing or other brazing. In addition, the connection short pipe (2) of the suction pipe (1) and the shell (2)
Although 1) has been described as having a circular cross section, it may have a square cross section. In this case, the shape of the baffle member (3) may be set to a rectangular cross section or the like in accordance with the tube shape.

[0019]

As described above, the present invention provides a method for brazing a metal pipe to an object to be brazed while contacting the inner surface of the brazed portion with an antioxidant gas. In the oxidation prevention method, a baffle member having an outer diameter smaller than the inner diameter of the pipe is disposed near the inside of the brazed portion, and an antioxidant gas is formed along the inner surface of the pipe from outside the peripheral surface of the baffle member. The inner surface of the portion to be brazed is brought into contact with an antioxidant gas by allowing the gas to flow therethrough. For this reason, it is not necessary to fill the entire pipe with the gas, and even if the amount of the antioxidant gas is small, the gas can be reliably guided to the inner surface of the brazing portion, and the oxidation of the inner surface is effectively performed. Can be prevented. Further, since it is not necessary to close the opening end of the suction pipe opposite to the gas supply side with a lid in order to fill the entire inside of the suction pipe with the gas, the time until brazing can be shortened, which is extremely efficient. is there.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state where a suction pipe is brazed to a shell of a compressor to be brazed.

FIG. 2 is a perspective view showing a baffle member and a gas supply member separately.

FIG. 3 is a perspective view showing a state where a suction pipe is brazed to a shell.

FIG. 4 is a perspective view showing a state before a suction pipe is brazed to a shell.

FIG. 5 is a sectional view of a shell and a suction pipe after brazing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Suction pipe (metal pipe) 2 ... Shell (object to be brazed) 21 ... Short connecting pipe 3 ... Baffle member 4 ... Gas supply member 43 ... Gas ejection port 5 ... Brazing material 6 ... Induction coil 7 ... Brazed part

Claims (1)

[Claims] 1. An inner surface oxidation during brazing of a metal pipe for brazing a metal pipe (1) to an object (2) to be brazed while contacting an inner surface of a part to be brazed (7) with an antioxidant gas. In the prevention method, a baffle member (3) having an outer diameter smaller than the inner diameter of the pipe is disposed near the inside of the brazed portion (7), and an antioxidant gas is supplied to the peripheral surface of the baffle member (3). A method for preventing oxidation of an inner surface of a metal pipe at the time of brazing, wherein the inner surface of the brazed portion (7) is brought into contact with an antioxidant gas by flowing in along the inner surface of the pipe (1) from the outside. .