JPH07266053A - Method and device for collecting welding fume - Google Patents

Abstract

PURPOSE:To provide a method and a device for collecting welding fume, by which the scatter of fume attached to a filter can be avoided, and the contamination of the environment can be prevented. CONSTITUTION:This device is equipped with a prefilter 3 composed of a refractory material such as ceramics, etc., and a main filter 4 having passing grain diameter of <=0.5mum. Gas containing welding fume is sucked from a sucking port 2 by a blower 6. At this time, a speed required when the gas containing welding fume passes through the main filter 4, must be >=0.01m/sec. Consequently, the fume is stuck to the filter 4 in the shape of solidified flakes, and since a bulk density becomes large, the fume becomes hard to scatter. Also, when cleaning the filter 4, purge gas is sprayed from the back of the filter 4 with a pressure of >=2kg/cm<2> to shake down the fume stuck to the filter 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding fume collecting method and a welding fume collecting apparatus for collecting welding fume generated by welding and maintaining a clean working environment.

[0002]

2. Description of the Related Art When performing welding work in factories and business establishments, it is necessary to remove welding fumes generated by the welding work from the work environment to maintain the work environment in a good condition. As a method of removing welding fume,
For example, perform welding work at the place where the exhaust system is installed,
It is conceivable to discharge the welding fumes together with air to the outside by the exhaust device. However, this method has the drawbacks that the equipment cost is high because the equipment is generally large and the welding place is limited.

In order to solve this drawback, a welding torch equipped with a hood which is lightweight and has a good intake efficiency has been proposed (Japanese Patent Publication No. 51-20305). In addition, a welding fume dust collector that has a sensor and in which the hood automatically moves in accordance with the progress of welding work has been proposed (Japanese Patent Publication No. Sho 60).
-78198).

However, when the hood is attached to the welding torch, the weight of the hood is limited, so that the welding torch becomes heavy and the workability is deteriorated. Also,
The welding fume dust collecting apparatus in which the hood automatically moves has the drawbacks that the apparatus becomes bulky and the working place is limited.

In order to solve these drawbacks, a welding fume suction torch has been proposed in which a shield gas discharge nozzle for discharging a shield gas and a suction nozzle for sucking welding fume are coaxially provided at the tip of the torch. It is actually used.

FIG. 6 is a plan view showing an example of this kind of welding fume suction torch. A shield gas discharge nozzle 11 for discharging shield gas is arranged at the tip of the torch. A suction nozzle 12 is arranged coaxially with the gas discharge nozzle 11 at a position slightly rearward of the tip of the shield gas discharge nozzle 11. A hole 12a for sucking the welding fumes is provided on the peripheral surface of the suction nozzle 12. These shield gas discharge nozzle 11 and suction nozzle 12 are supported by an elbow pipe 13,
The elbow pipe 13 is supported by the grip portion 14. The grip portion 14 is provided with a suction force adjusting hole 14a, and the amount of gas sucked from the suction nozzle 12 can be adjusted.

The grip portion 14 and the cable hose 16
A vent mechanism 15 is provided between and to facilitate bending of the torch. And the cable hose 16
An adapter connection portion 17 is provided at the rear end portion. The adapter connection part 17 is provided with a hose connection port 17a, and is connected to a fume recovery device described later via a connection hose.

An adapter 18 is connected to the adapter connecting portion 17. The adapter 18 is provided with a shield gas supply hole 18a and an electric cable connector 18b. Shield gas and welding power are supplied via the adapter 18.

The cable hose 16 is a double pipe as shown in FIG. 7, for example. That is, the inner tube is composed of the power cable 22 and the rubber coating material 21. A liner 20 (for example, a spring liner or the like) is arranged in the inside pipe, and the welding wire passes through the liner 20. And this liner 20 and power cable 22
Shield gas is designed to flow between the and. Further, the gas sucked from the suction nozzle 12 flows between the rubber coating material 21 and the outer pipe 23.

FIG. 8 is a schematic view showing the tip of the torch.
The weld gas is shielded from the air by the shield gas A discharged from the shield gas discharge nozzle 11 at the tip of the torch,
Prevents oxidation of weld metal. On the other hand, the gas B outside the shield gas region near the welded portion is sucked through the hole 12 a provided in the suction nozzle 12. The gas sucked from the suction nozzle 12 contains welding fumes generated by welding. The gas containing the welding fume passes between the rubber coating material 21 of the cable hose 16 and the outer pipe 23, and enters the welding fume recovery device via the hose connected to the hose connection port 17a of the adapter connection part 17. .

FIG. 9 is a schematic view showing an example of a conventional welding fume recovery device. This welding fume recovery device 31
Is provided with a filter 32 for capturing the welding fumes, a fan 33 for generating a suction force, and a motor 34 for rotating the fan 33. Suction nozzle 1
When the gas sucked from 2 passes through the filter 32, the welding fumes adhere to the filter 32, and the gas from which the welding fumes have been removed is discharged from the recovery device.

Generally, the flow velocity of the gas sucked from the suction nozzle when passing through the filter 32 is 0.001 to
0.002 m / sec, and the welding fume adheres to the filter 32 in the form of cotton. In addition, when welding fumes adhere to the filter 32 and the suction force decreases, the filter 32 is removed from the recovery device, and the filter 3 is removed by a suction type vacuum cleaner.
The filter 32 is cleaned by removing the welding fume adhering to 2 or washing away the welding fume adhering to the filter 32 with water.

[0013]

However, in the conventional welding fume collecting apparatus, the welding fume adheres to the filter in a cotton shape as described above. Since this cotton-like fume has a low bulk density, it is extremely likely to be scattered, and for example, when cleaning the filter, it may be scattered by a slight wind to pollute the environment.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a welding fume collecting method and a welding fume collecting apparatus capable of avoiding scattering of fumes adhering to a filter and preventing environmental pollution. To aim.

[0015]

A welding fume collecting method according to the present invention is a welding fume collecting method for sucking gas containing welding fume and collecting the welding fume,
The welding fume-containing gas is passed through a filtration filter having a passing particle diameter of 0.5 μm or less at a speed of 0.01 m / sec or more,
The method further comprises the step of attaching the welding fumes to the filtration filter.

The welding fume collecting apparatus according to the present invention sucks the welding fume-containing gas containing the welding fume and the filtering filter having a passing particle diameter of 0.5 μm or less and 0.01 m of the welding fume-containing gas into the filtration filter. And a purge gas spraying unit for spraying a purge gas at a pressure of ² kgf / cm ² or more from the downstream side in the flow direction of the welding fume-containing gas to the filtration filter. .

[0017]

In the present invention, a filter having a passing particle diameter of 0.5 μm or less is used, and the gas passing the welding fumes is passed through the filter at a speed of 0.01 m / sec or more. Then, the welding fume contained in the welding fume-containing gas is brought into contact with the filter at a high speed, and is solidified into a scaly shape by the pressure at the time of contact, and is captured by the filter. Since the scale-like fumes have a large bulk density, they are difficult to scatter, and do not scatter even if the wind speed is 3 to 4 m / min. Therefore, there is no possibility that the fumes collected during the cleaning of the filter will scatter, and the pollution of the environment can be prevented.

However, the particle size passing through the filter is 0.5 μm.
When the flow rate of the welding fume-containing gas is less than 0.01 m / sec, the fumes captured by the filter become cotton-like and have a low bulk density and are easily scattered. Therefore, the particle size of the particles passing through the filter must be 0.5 μm or less, and the velocity of the welding fume-containing gas when passing through the filter must be 0.01 m / sec or more.

After the suction of the welding fume-containing gas is stopped, the pressure is 2 k from the downstream side in the flow direction of the welding fume-containing gas with respect to the filter in which the fumes adhere to the scale.
When a purge gas of gf / cm ² or more is blown, the scale-like fumes easily separate from the filter and accumulate in a dust box arranged below the filter, for example. By doing so, the filter can be cleaned without removing the filter from the apparatus, and the filter cleaning operation becomes extremely simple. In this case, the purge gas blown to the filter may be compressed air, for example. However, in this case, a device such as a compressor is required. On the other hand, carbon dioxide gas (CO ₂ ) or argon gas (Ar) is used as a shield gas at the welding site. If these gases are used as the purge gas, a device such as a compressor becomes unnecessary and the filter is cleaned. Can be easily implemented. Further, since these gases have a higher density and a stronger inertial effect than air, there is an advantage that fumes can be efficiently removed from the filter. Therefore, it is preferable that the purge gas is provided by the shield gas supply means.

[0020]

Embodiments of the present invention will now be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing a welding fume recovery device according to an embodiment of the present invention. A blower 6 is arranged in the device casing 1, and a fan 5 for this blower 6 is installed.
By rotating, the gas containing the welding fumes is sucked from the suction port 2. This suction port 2
It is connected to a welding torch or hood by a connecting hose. A pre-filter 3 and a main filter 4 are arranged between the suction port 2 and the blower 6. The prefilter 3 is made of a refractory material such as ceramics,
The pore size (passing particle size) is set to be relatively large. The main filter 4 is made of, for example, an aramid fiber coated with a fluororesin, and the passing particle diameter is set to 0.5 μm or less. A dust box (not shown) is provided below the main filter 4, and fumes blown off from the main filter 4 are accumulated in the dust box as described later. Blower 6
Has the ability to have a flow velocity of 0.01 m / sec or more when the sucked gas passes through the filter 4.

This welding fume recovery device is provided with a purge gas supply port 7. This purge gas supply port 7
For example, 2 kgf / cm ² from a shield gas cylinder
Carbon dioxide gas or argon gas having the above pressure is supplied. The gas supplied to the purge gas supply port 7 passes through the electromagnetic valve 8 and is blown onto the filter 4 from the back side (blower 6 side) of the filter 4.

Next, the operation of the welding fume collecting apparatus according to this embodiment having the above structure will be described. However, in the following description, the case of connecting to the welding torch shown in FIG. 6 will be described.

First, the hose connection port 17a of the welding torch shown in FIG. 6 and the suction port 2 of the apparatus of this embodiment are connected by a connection hose. Then, the blower 6 is rotated to start welding. As a result, the fumes generated by the welding are sucked from the suction nozzle of the welding torch and enter the welding fume collecting apparatus according to this embodiment through the connecting hose. A sensor for detecting the welding current may be provided so that the blower 6 automatically rotates during welding.

The gas sucked from the suction nozzle contains coarse solids such as spatters in addition to the welding fumes. These coarse solids are captured by the prefilter 3. As a result, it is possible to prevent the main filter 4 from being burned and damaged by impact. The welding fume-containing gas that has passed through the pre-filter 3 passes through the main filter 4 at a speed of 0.01 m / sec or more. At this time, the welding fumes in the welding fumes-containing gas are not filtered by the main filter 4
Are trapped on the surface of the main filter 4 and adhere to the surface of the main filter 4 in the form of scales.

In FIG. 2, the horizontal axis represents the velocity of the welding fume-containing gas when passing through the main filter (filter passing wind velocity), and the vertical axis represents the bulk density of the recovered fume adhering to the main filter. It is a graph which shows the relationship between the filter passing wind speed in the filter of a diameter, and the bulk density of collection | recovery fume. As is clear from FIG. 2, when the filter particle diameter is 0.5 μm or less and the filter air velocity is 0.01 m / sec or more, the bulk density of the recovered fumes is 0.20 g / cm 2. It becomes ³ or more and becomes scale-like (solid). On the other hand, the bulk density of the recovered fumes is less than 0.20 g / cm ³ when the filter particle size is less than 0.5 μm and the filter air velocity is less than 0.01 m / sec. (Amorphous) Such cotton-like fumes are extremely easy to scatter. Therefore, the passing particle diameter of the main filter 4 must be 0.5 μm or less, and the flow velocity of the welding fume-containing gas when passing through the main filter must be 0.01 m / sec or more.

The fumes adhering to the filter 4 in the form of scales are removed from the filter 4 as follows. That is,
After the welding is completed or when the welding is temporarily stopped, the electromagnetic valve 8 is operated in a pulsed manner, and the purge gas supplied to the purge gas supply port 7 is supplied to the filter 4 for 0.2 seconds, for example. Spray 3 times at intervals of 3 seconds. Then, the fumes adhering to the filter 4 in the form of scales are removed from the filter 4 and fall into the dust box arranged below the filter 4. When the fumes are accumulated in the dust box to some extent, the dust box is removed and the fumes are treated like normal dust. In this case, the recovered fumes are hardened in the form of scales and have a large bulk density, and thus are difficult to scatter. Therefore,
It is possible to avoid the risk of polluting the environment.

In FIG. 3, the horizontal axis represents the arc time, and the vertical axis represents the flow velocity (m) passing through the suction duct hose having a diameter of 38 mm.
/ Sec), and the purge gas having a pressure of 2 kgf / cm ² (2 atm) is sprayed in a pulse shape of 3 to 7 strokes (repetition number) per time, and the arc time and the flow velocity passing through the suction duct hose. It is a graph which shows the relationship with. As is clear from FIG. 3, when the arc time is long, the larger the number of strokes, the greater the recovery of the flow velocity passing through the suction duct hose.

In FIG. 4, the horizontal axis represents the arc time, and the vertical axis represents the flow velocity (m in the suction duct hose with a diameter of 38 mm).
/ Sec) and the pressure of the purge gas is 2 to 5 kgf / c
m ² and (2-5 atm) is a graph showing the relationship between a passing flow rate of the arc time and a suction duct hose when blowing purge gas in one stroke pulsed per. As is clear from FIG. 4, when the arc time becomes long, the higher the pressure of the purge gas, the greater the recovery of the passage flow velocity in the suction duct hose.

In FIG. 5, the horizontal axis represents the arc time, and the vertical axis represents the flow velocity (m in the suction duct hose with a diameter of 38 mm).
/ Sec), and shows the relationship between the arc time and the flow velocity in the suction duct hose when the purge gas with a pressure of 3 kgf / cm ² (3 atm) is sprayed in a pulse shape of 3 or 5 strokes each time. It is a graph figure. As is clear from FIG. 5, the pressure of the purge gas is 3 kgf / cm.
When it is ² , if the number of strokes is 3 or more, there is no significant difference in the recovery rate of the flow velocity in the suction duct hose.

The pressure of the purge gas is 2 kgf / cm.
If it is less than ² and the number of strokes effect dislodge For 2 or less is not sufficient. Therefore, the pressure of the purge gas is 2 kgf / cm ² (more preferably 4 to 5 kgf / cm ² ).
cm ² ), and it is preferable to repeatedly spray 3 or more strokes.

As described above, in the present embodiment, since the welding fume can be collected in a scale-like solidified state, it is possible to prevent the collected fume from scattering in the environment. Further, in this embodiment, since the fumes adhering to the filter are blown off from the filter by blowing the purge gas from the back surface of the filter 4, it is not necessary to remove the filter 4 from the device in the normal cleaning, and the cleaning of the filter is extremely difficult. It's easy. Further, in the present embodiment, the welding fume-containing gas is passed through the filter at a high speed, so that the fume recovery efficiency of the filter is high and the size of the filter can be reduced. This allows
There is also an effect that the device can be downsized.

[0032]

As described above, according to the method of the present invention, a filter having a passing particle diameter of 0.5 μm or more is used,
Since the welding fume-containing gas is passed through at a speed of 0.01 m / sec or more, the fumes adhere to the filter in the form of scale-like solidification. Therefore, the bulk density of the recovered fume is large, and it is possible to avoid scattering of the fume. Further, the purging gas is blown to the filter to blow off the fumes adhering to the filter, whereby the filter can be cleaned very easily.

Further, according to the apparatus of the present invention, it is possible to collect the welding fume in a solid state, prevent the collected fume from scattering into the environment, and it is possible to miniaturize the apparatus. Play.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a welding fume recovery device according to an embodiment of the present invention.

FIG. 2 is a graph showing a relationship between a filter passing wind velocity and a bulk density of recovered fumes in filters having various passing particle diameters.

FIG. 3 is a graph showing the relationship between the arc time and the flow velocity in the suction duct hose when the pressure of the purge gas is 2 atm and the number of strokes is 3 to 7.

FIG. 4 is a graph showing the relationship between the arc time and the flow velocity in the suction duct hose when the pressure of the purge gas is 2 to 5 atmospheres and the number of strokes is 1.

FIG. 5 is a graph showing the relationship between the arc time and the flow velocity in the suction duct hose when the pressure of the purge gas is 3 atm and the number of strokes is 3 to 5.

FIG. 6 is a plan view showing an example of a welding fume suction torch.

FIG. 7 is a cross-sectional view showing a cable hose.

FIG. 8 is a schematic diagram showing a torch tip portion.

FIG. 9 is a schematic view showing an example of a conventional welding fume recovery device.

[Explanation of symbols]

 1; Case 2; Suction port 3; Pre-filter 4; Main filter 5, 33; Fan 6; Blower 7; Purge gas supply port 8; Electromagnetic valve 11; Discharge nozzle 12; Suction nozzle 14; Cable hose 17; Adapter connection part 17a; Hose connection port 18; Adapter 32; Filter

Claims (4)

[Claims] 1. A welding fume recovery method for sucking a gas containing welding fume to recover the welding fume,
The welding fume-containing gas is passed through a filtration filter having a passing particle diameter of 0.5 μm or less at a speed of 0.01 m / sec or more,
A method for collecting welding fume, comprising the step of attaching the welding fume to the filtration filter. 2. After the suction of the welding fume-containing gas is stopped, a purge gas having a pressure of 2 kgf / cm ² or more is blown onto the filtration filter from the downstream side in the flow direction of the welding fume-containing gas to adhere to the filtration filter. The welding fume collecting method according to claim 1, further comprising a step of removing the weld fume that has been formed. 3. The welding fume recovery method according to claim 2, wherein the purge gas is supplied by a shield gas supply means for supplying a shield gas around the arc. 4. A filtration filter having a passing particle diameter of 0.5 μm or less, and a welding fume-containing gas containing welding fumes, and the welding fume-containing gas is passed through the filtration filter at a speed of 0.01 m / sec or more. A welding fume collecting device comprising: a suction means and a purge gas blowing means for blowing a purge gas onto the filtration filter from a downstream side in a flow direction of the welding fume-containing gas at a pressure of ² kgf / cm ² or more.