CN103252550B - Method for gas replacement before brazing of small-scale gas cylinder - Google Patents

Abstract

The invention relates to a method for manufacturing a 30-ounce disposable gas cylinder, in particular to a method for gas replacement before brazing of a small-scale gas cylinder. According to the method for the gas replacement before the brazing of the small-scale gas cylinder, after a bottle body is assembled, inert gases are added into the bottle body for the gas replacement technology before the assembled bottle body is placed on a high-temperature resistant band chain of a bottle feeding zone of a channel type environment protecting brazing furnace. According to the method for the gas replacement before the brazing of the small-scale gas cylinder, the bottle body is prevented from detonation caused by mixture of gas inside the bottle and gas inside the furnace in the process of brazing, so that scrapping of the bottle body and times of fault shutdown of a brazier are reduced and the percent of pass of product production and production efficiency are improved.

Description

A Gas Replacement Method Before Brazing of Small Gas Cylinders

technical field

The invention belongs to the technical field of processing small gas cylinders, and in particular relates to a manufacturing method of a 30-ounce disposable gas cylinder.

Background technique

30-ounce disposable gas cylinders are widely used abroad, and the most basic requirement for a production line is about 100,000 per month. The welding process of disposable gas cylinders in the prior art is completed in a continuous reducing protective atmosphere brazing furnace, as shown in Figure 1, the specific operation method is: the assembled bottle body is placed in the bottle inlet area On the high temperature resistant mesh belt chain, place anti-rolling pads on the mesh belt chain, and hang the required brazed oxygen-free copper wire on the part of the bottle body that needs to be brazed. The bottle body on the high-temperature-resistant mesh belt chain slowly enters the tunnel furnace body along with the driving wheel of the mesh belt chain, and is heated to about 1100°C in the heating zone. At this time, the oxygen-free copper wire solder melts, and at the same time, the oil on the surface of copper and steel is completely vaporized at high temperature, and the oxides on the surface of copper and iron are completely reduced to metallic copper and metallic iron by atomic hydrogen at high temperature. The melted oxygen-free copper melt has strong fluidity, and the surface tension of the reduced steel is very small. The oxygen-free copper melt penetrates into the required welding parts in close contact through capillary action. After that, the bottle body gradually cools down as it enters the cooling zone with the high-temperature-resistant mesh belt chain, and the oxygen-free copper melt that penetrates into the required welding parts in close contact re-solidifies and gradually cools down. After brazing in the bottle outlet area, the bottle body is released from the furnace. At this time, the bottle body and the anti-roll pad are removed here, and the whole welding process ends.

However, because the inside of the bottle body to be brazed is a nearly closed system, only a hole of about 3.5mm on the valve seat communicates with the outside world. When the bottle body enters the furnace, there is air in the bottle, and the ambient gas is a reducing gas composed of hydrogen and nitrogen generated by the ammonia decomposition furnace. As the gas cylinder moves in the furnace, the temperature rises from normal temperature to about 1100°C and then cools down to normal temperature. In this process, a small amount of ambient gas inevitably enters the inside of the bottle. If combined with the high temperature of the environment, sometimes the hydrogen in the furnace and the oxygen in the cylinder will produce gas detonation. If this happens before the brazing is completed, the assembled bottle will split; if it happens after the brazing is completed, the brazed bottle will be displaced on the high-temperature-resistant mesh belt chain, and the bottle will generally be scrapped. Seriously, it will cause blockage due to the confusion of the bottle body in the furnace position, forcing the continuously running brazing furnace to cool down and shut down for troubleshooting.

Contents of the invention

The technical problem mainly solved by the present invention is to provide a new manufacturing method of a 30-ounce disposable gas cylinder, which can prevent the gas cylinder from mixing with the gas in the furnace to cause detonation during the brazing process, causing the cylinder to be scrapped , and even the brazing furnace cooling shutdown failure.

In order to solve the above-mentioned technical problems, the present invention adopts a process of gas replacement after the bottle body is assembled and placed on the high-temperature-resistant mesh belt chain in the bottle-entry area of the channel-type atmosphere protection brazing furnace. It is characterized in that its steps are:

1) Remove the assembled bottle body 3 from the conveying line.

2) Put the bottle body 3 upright.

3) Insert the slender nozzle 2 of the air gun from the 3.5mm hole on the valve seat 1 to the bottom of the bottle body 3.

4) Turn on the switch of the gas filling gun, put the inert gas under pressure into the bottle body 3, turn off the gas filling gun after a few seconds and pull it out from the hole.

5) Place the bottle body 3 that has completed the gas replacement on the high-temperature-resistant mesh belt chain in the bottle-entry area of the channel-type atmosphere protection brazing furnace.

After the above-mentioned gas replacement in the bottle is completed, continue the follow-up operation of the brazing of the disposable gas bottle.

After adopting this method, it can effectively prevent the bottle body from detonating due to the mixture of gas in the bottle and gas in the furnace during the brazing process, thereby reducing the scrapping of the bottle body and the chance of stopping the brazing furnace for failure, improving the qualified rate of product production, and improving Productivity.

Description of drawings

Fig. 1 channel type atmosphere protection brazing furnace schematic diagram of the present invention;

Fig. 2 is a structural schematic diagram of gas replacement before brazing of a small gas cylinder according to the present invention.

Detailed ways

A gas replacement method before brazing of a small gas cylinder: after the bottle body is assembled, it is carried out before being placed on the high-temperature-resistant mesh belt chain in the bottle-entry area of a channel-type atmosphere protection brazing furnace. As shown in Figure 2, the following steps are included:

1) Remove the assembled bottle body 3 from the conveying line.

2) Put the bottle body 3 upright.

3) Insert the slender nozzle 2 of the air gun from the 3.5mm hole on the valve seat 1 to the bottom of the bottle body 3.

4) Turn on the switch of the gas filling gun, put the inert gas under pressure into the bottle body 3, turn off the gas filling gun after a few seconds and pull it out from the hole.

5) Place the bottle body 3 that has completed the gas replacement on the high-temperature-resistant mesh belt chain in the bottle-entry area of the channel-type atmosphere protection brazing furnace.

6) Continue the follow-up operation of disposable gas cylinder brazing.

In addition, the slender nozzle 2 of the air-filling gun in step 3 is a brass tube with an outer diameter of 2.5 mm, a wall thickness of 0.25 mm, and a length of 200 mm.

In addition, the inert gas in step 4 is nitrogen.

In addition, the pressure of the inert gas in step 4 is 0.4 MPa, and the gas addition time is 3 seconds.

Claims (2)

1. The gas replacement method before brazing of small gas cylinders is characterized in that: after the bottle body (3) is assembled, it is placed on the high-temperature-resistant mesh belt chain in the bottle inlet area of the channel-type atmosphere protection brazing furnace, and the gas replacement is carried out Methods: 1) Remove the assembled bottle (3) from the conveyor line; 2) Put the bottle body (3) vertically upward; 3) Insert the slender nozzle (2) of the air filling gun from the hole on the valve seat (1), and go deep into the bottom of the bottle body (3). The diameter of the hole on the valve seat (1) is 3.5mm; 4) Turn on the gas filling gun switch, add inert gas with a pressure of 0.4MPa into the bottle body (3), after 2-6 seconds, close the gas filling gun and pull it out from the hole of its valve seat (1); 5) Place the bottle body (3) that has completed the gas replacement on the high temperature resistant mesh belt chain in the bottle inlet area of the channel type atmosphere protection brazing furnace. 2. The gas replacement method before brazing of small gas cylinders according to claim 1, characterized in that: the materials of the valve seat (1) and the bottle body (3) are all carbon steel, and the brazing filler metal is oxygen-free copper wire .