JP3369634B2 - Manufacturing method of palladium tube - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a pipe made of metallic palladium or a palladium alloy such as palladium-silver, which is installed in a hydrogen gas discharge device of an absorption refrigerator.

[0002]

2. Description of the Related Art In an absorption type refrigerator, Japanese Patent Laid-Open No. 63-
As disclosed in Japanese Laid-Open Patent Application No. 254362, Japanese Utility Model Laid-Open No. 64-8174, Japanese Unexamined Patent Publication No. 5-9001 and the like,
If hydrogen gas is generated inside the machine due to metal corrosion,
Since the efficiency of the refrigeration cycle decreases significantly, a tube usually made of palladium metal or a palladium alloy such as palladium-silver (hereinafter collectively referred to as palladium tube)
A non-condensable gas discharge device equipped with the above is used to extract a non-condensable gas such as hydrogen gas, and the hydrogen gas is discharged to the outside of the machine through a wall of a palladium pipe heated to about 350 ° C.

As shown in FIG. 2, the palladium tube 4 used in the hydrogen gas discharge device is manufactured mainly by a process combining rolling and welding.

That is, a palladium plate 1 rolled to a predetermined plate pressure is formed into a circular cross section using a forming roll or the like,
The butted portion or the superposed portion is joined by, for example, TIG welding. This welded pipe 4a is expanded to have a predetermined pipe diameter, for example, 12 mm. Then, this is cut into a predetermined length, and one end of the cut palladium element tube 4b is rounded,
This rounded portion is sealed by TIG welding, laser welding, or the like. Then, the final shape is finished by subjecting the opening end portion to flare processing.

[0005]

However, the above-mentioned conventional method for producing a palladium tube is not only disadvantageous in that the number of steps is large and the production cost is high, but also the work of narrowing one end of the palladium element tube 4b ( The step f) and the operation of sealing the one end by welding (step g) can be reliably performed.
There was a problem that it was extremely difficult.

In other words, it is extremely difficult to quantify the work (step f) in which one end of the palladium shell 4b, which has been thinned through the drawing tube (step d), has a good shape, and is numerically managed. However, there were many parts that proceeded depending on the intuition of the worker, and it was extremely difficult to maintain the quality. It is very difficult to securely seal the end part squeezed by such difficult work, no matter how careful welding is performed, and it is necessary to perform a strict inspection on the product. It was

Further, even if the palladium tube 4 has passed the inspection, if there is an extremely thin portion, the thin portion may be opened during use and the normal hydrogen gas discharging function cannot be achieved. There were some problems mentioned above, and the solution to these problems was a problem.

[0008]

As a concrete means for solving the above-mentioned problems of the prior art, the present invention uses a plate of palladium or an alloy thereof having an elongation of 20% or more as a rod-shaped recess in the receiving die. Press-fitting using a pressing die of, one end is closed, the other end is press-molded into a pipe having an opening, a method for manufacturing a palladium pipe,

[0009] A plate of palladium or its alloy that has been heated above the recrystallization temperature is press-fitted into the recess of the receiving die using a rod-shaped pressing die, and pressed into a tube with one end closed and the other end open. A method for manufacturing a palladium tube characterized by molding,

A plate of palladium or its alloy heated to a temperature higher than the recrystallization temperature is press-fitted into a concave portion of a receiving die using a rod-shaped pressing die, and is pressed into a tube having one end closed and the other end open. When forming, the inert gas is blown to the side of the plate facing the pressing die, and the air in the recess is sucked and exhausted from the air hole provided in the deepest part of the recess of the receiving die. A method for manufacturing a palladium tube and a method for manufacturing the same are provided to solve the above-mentioned problems of the prior art.

[0011]

[Function] A plate of palladium or its alloy (hereinafter collectively referred to as a palladium plate) is press-fitted into a recess of a receiving mold using a rod-shaped pressing die, and is press-formed into a tube having one end closed and the other end open. In this case, a palladium plate having an elongation of 20% or more can be plastically deformed into a tube without causing cracks, and even when the palladium plate has a small elongation in the as-rolled state, the temperature exceeds the recrystallization temperature. When heated, the deformation resistance is reduced so that the tube can be made without cracking.

Further, if an inert gas is blown to the side of the palladium plate facing the pressing die and the air in this portion is sucked and exhausted from the air hole provided at the deepest portion of the recessed portion of the receiving die, the oxygen partial pressure is reduced. Therefore, even if the palladium plate is heated to a recrystallization temperature or higher and press-formed, the surface is not oxidized.

[0013]

Embodiments of the present invention will now be described in more detail with reference to FIG.

Reference numeral 2 in the drawing denotes a pressing die having an elongated body and having sufficient rigidity and heat resistance, which is made of, for example, Cr-Mo heat-resistant steel. In the pressing die 2, the body is formed to have a circular cross section, the tip (downward in the drawing) is rounded, and the base (upward in the drawing) is gently expanded.
Then, gas holes 21 and 22 are provided so that the inert gas can be blown from the tip portion and the plurality of side surface portions,
It is adapted to communicate with an inert gas cylinder (not shown) via the gas pipe 23. Further, a coil 24 is arranged around the tip side body portion so that high frequency heating can be performed.

Reference numeral 3 denotes a receiving die corresponding to the pressing die 2, which also has sufficient rigidity and heat resistance, for example, Cr-.
It is formed of Mo-based heat-resistant steel or the like. The receiving die 3 has a wide flat portion 31 on the upper portion thereof so that the palladium plate 1 can be placed horizontally without protruding the end portion thereof. Then, a concave portion 32 having a circular cross section for press-fitting the palladium plate 1 into the central portion by the pressing die 2 is provided.
Are formed through the slope 33. In addition, the concave portion 3
An air hole 34 is bored in the deepest portion of 2 so that it can be appropriately connected to or opened via a pipe 35 to either a vacuum pump or a compression pump (not shown). A coil 36 is also arranged around the body of the receiving die 3 so that high frequency heating can be performed.

According to the present invention, the pressing die 2 and the receiving die 3 having the above-mentioned structure are used.
And are used to press-form a palladium plate 1 made of palladium metal such as palladium metal or palladium-silver to obtain a product palladium tube 4. The palladium plate 1 is annealed to reduce its hardness, If the elongation is 20% or more, especially 30% or more, the coil 2
4. The palladium plate 1 is placed in the receiving die 3 without passing a high-frequency current through it, that is, at room temperature without heating.
The press die 2 mounted on the flat part 31 of the above is lowered and pressed into the recess 32, one end is closed and the other end is opened, and the press die 2 is gradually expanded. The palladium tube 4 having the flare 41, which is pressed and formed by the base portion and the slope 33 of the die 3 on the open end side, is obtained.

If the palladium tube 4 is cracked when the product of the palladium tube 4 is obtained by a single press work because the palladium plate 1 is thick and the curvature of the tip of the pressing die 2 is large. You can press it separately. That is, the pressing die 2 may not be pressed all the way into the recess 32 at once, but may be interrupted at an appropriate intermediate stage, the semi-finished product may be annealed and then repressed.

By the way, when the palladium plate 1 is press-fitted into the concave portion 32 of the receiving die 3 using the pressing die 2, the air holes 34 are formed.
Since the internal pressure of the recessed portion 32 does not rise even if the palladium plate 1 is press-fitted by simply opening it without communicating it with either the vacuum pump or the compression pump, the high-pressure air causes the palladium plate 1 to move. There is an advantage that the problem that a groove-like mark is formed when passing between the mold and the die 3 does not occur.

When the palladium plate 1 is as-rolled and has little elongation, a high-frequency current is passed through the coils 24 and 36 to rapidly heat the pressing die 2 and the receiving die 3 to place them on the receiving die 3. When the palladium plate 1 is rapidly heated to a recrystallization temperature or higher, for example, about 600 to 800 ° C., and the press molding is performed by the pressing die 2 and the receiving die 3 while maintaining this temperature, the deformation resistance is significantly reduced. Since it is easily plastically deformed, the palladium tube 4 free from defects such as cracks can be reliably obtained.

Since the palladium plate 1 is heated for a relatively long time even if it is rapidly heated by a high frequency, in this case, an inert gas such as nitrogen gas is supplied from the gas pipe 13 for the purpose of preventing surface oxidation. Sending in, gas holes 21 and 22
And the upper surface of the palladium plate 1 is covered with an inert gas. Further, the pipe 35 is connected to a vacuum pump (not shown), and the air in the recess 32 is sucked and exhausted from the air holes 34 to prevent the back surface of the palladium plate 1 from being oxidized.

That is, the recess 32 is formed through the air hole 34.
By sucking and discharging the air, the oxygen partial pressure in the recess 32 is reduced, and the palladium plate 1 becomes difficult to oxidize. In addition,
Even if there is a gap between the palladium plate 1 and the flat portion 31, the gas flowing into the recessed portion 32 whose pressure has dropped from here is sent from the pipe 23 and the inert gas blown onto the upper surface of the palladium plate 1. Therefore, oxidation does not proceed in the inflow part.

In addition, the palladium plate 1 is previously provided with an inert gas,
For example, in an electric furnace in an argon gas atmosphere or the like, the recrystallization temperature or higher, for example, at 800 ° C. is maintained for about 30 minutes to obtain 600 ° C.
It is also possible to perform the press molding using the pressing die 2 and the receiving die 3 before going down to the following.

When the hot palladium plate 1 is pressed in the atmosphere, the surface is oxidized. In this case, the scale is removed by pickling to obtain the final product.

The press-molded palladium tube 4 is attached to the receiving mold 3
When extracting from the concave portion 32, an appropriate gas from the air hole 34, for example, an inert gas such as nitrogen gas / argon gas when there is a strong concern that the palladium tube 4 is oxidized at a high temperature, and compressed when there is no concern of oxidation at a low temperature It is possible to facilitate the extraction by blowing air or the like.

By the way, since the present invention is not limited to the above-mentioned embodiments, various modifications can be made within the scope of the claims.

[0026]

As described above, according to the present invention, a palladium plate having an elongation of 20% or more is press-fitted into the recess of the receiving die by using a rod-shaped pressing die, one end of which is closed and the other end of which is closed. A method for manufacturing a palladium tube, which comprises press-molding an open tube,

A palladium plate heated to a temperature higher than the recrystallization temperature is press-fitted into a concave portion of a receiving die using a rod-shaped pressing die to press-form a tube having one end closed and the other end open. It is a characteristic method for manufacturing a palladium tube,

When a palladium plate heated to the recrystallization temperature or higher is press-fitted into the recess of the receiving die using a rod-shaped pressing die to press-form a tube with one end closed and the other end open, Manufacture of a palladium pipe characterized in that an inert gas is blown to the side of the palladium plate facing the pressing die, and the air in the recess is sucked and exhausted from an air hole provided in the deepest part of the recess of the receiving die. Because it is a method

First, a thick welded pipe is manufactured, and this is drawn and cut into a predetermined pipe diameter and length to make a raw pipe, one end of the raw pipe is closed, and this portion is TIG welded or laser welded. Compared with the conventional method for producing a palladium tube, which is said to be clogged by the above, not only the number of steps is greatly reduced, but also the welding step of which quality control is difficult can be eliminated, so that the quality of the palladium tube is significantly improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an example.

FIG. 2 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

1 Palladium plate 2 push die 21 and 22 gas holes 23 gas pipe 24 coils 3 Receiving mold 31 Flat part 32 recess 33 slope 34 air holes 35 pipes 36 coils 4 Palladium tube 41 flare 4a Welded pipe 4b Palladium tube

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-254362 (JP, A) JP-A-63-204085 (JP, A) JP-A-59-101282 (JP, A) JP-A-5- 9001 (JP, A) JP 5-39587 (JP, A) JP 63-197857 (JP, A) JP 4-311542 (JP, A) Jitsuko 47-19970 (JP, Y1) (58) Fields investigated (Int.Cl. ⁷ , DB name) F25B 43/04

Claims (3)

(57) [Claims] 1. A plate of palladium or an alloy thereof having an elongation of 20% or more is press-fitted into a recess of a receiving die by using a rod-shaped pressing die, and is pressed into a tube having one end closed and the other end open. A method for manufacturing a palladium tube, which comprises molding. 2. A pipe in which a plate of palladium or an alloy thereof heated to a recrystallization temperature or higher is press-fitted into a recessed portion of a receiving die using a rod-shaped pressing die, one end of which is closed and the other end of which is open. 1. A method for manufacturing a palladium tube, which comprises press-molding into. 3. A tube in which a plate of palladium or an alloy thereof heated to a recrystallization temperature or higher is press-fitted into a recessed portion of a receiving die using a rod-shaped pressing die to close one end and open the other end. When press-molding, the inert gas is blown to the side of the plate facing the pressing die, and the air in the recess is sucked and exhausted from the air hole provided in the deepest part of the recess of the receiving die. And a method for manufacturing a palladium tube.