JP3076987B2 - Local exhaust ventilation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a local exhaust system.

[0002]

Dust damage due to welding fumes resulting from arc welding operations is still considerable in the number of new pneumoconiosis findings. Therefore, in response to a strong request from the Ministry of Labor, the Japan Welding Association has formulated a Dust Prevention Measures Promotion Campaign Implementation Plan, and has been promoting promotion campaigns, such as calling on welding establishments nationwide to thoroughly disseminate dust prevention measures. doing.

[0003] As part of this propulsion campaign, matters concerning the promotion of the installation of local exhaust systems are included in the promotion guidelines. As an example of a conventional local exhaust device, there is an apparatus disclosed in Japanese Patent Publication No. 6-70512. As shown in FIG. 2, this device blows air from the air-blow-out pipe b to the front of the curved wall a and sucks it toward the curved wall a through the suction port c to form a vortex d. It is configured so that the contaminated air e is sucked by d and exhausted.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the local exhaust system utilizing the above-mentioned eddy current, and to provide a local exhaust system capable of more effectively preventing dust damage. .

[0005]

As a means for solving the above-mentioned problems, the present invention blows air toward the front of a curved wall and sucks air toward the curved wall to form a vortex. In the local exhaust device that sucks and exhausts air, direct injection air is blown directly to the vicinity of the worker's head located in front of the curved wall, and detour air for adjusting the blowout amount of the direct injection air. In addition to the set conditions of the vortex flow, the blowout ratio, blowout amount, blowout speed, and blowout direction of the direct injection air and bypass air are adjusted to prevent the direct injection air and bypass air from working. A local exhaust device is provided which is configured to join the vortex without passing through a range.

Further, in a local exhaust device which blows out air to the front surface of the curved wall and sucks it toward the curved wall side to form a vortex, and sucks and exhausts contaminated air by the vortex, the local vortex is used as the vortex. And, the purified air is blown directly as a direct injection air near the worker's head located in front of the curved wall, and is also blown as a bypass air for adjusting the blowing amount of the direct injection air, In addition to the set conditions of the vortex, the direct injection air and the bypass air are adjusted by adjusting the blowing ratio, the blowing amount, the blowing speed, and the blowing direction of the direct injection air and the bypass air to allow the direct injection air and the bypass air to pass through a range that hinders the work. A local exhaust device characterized in that the local exhaust device is configured to be joined to the vortex without using the vortex.

[0007]

Embodiments of the present invention will be described below with reference to FIG. In the following description, the exhaust of the welding fume will be described as an example. However, the present invention can be used not only for removing dust, gas, odor, oil mist, etc., but also for the apparatus of the present invention.

<A> Housing The housing 1 includes a top plate 11, a rear wall 12, and side walls 1 on both sides.
3 (one side not shown), and has a box shape in which an opening 14 is formed on the side facing the back wall 12. Also,
At the bottom of the opening 14, a worktable 15 is formed which projects horizontally from the rear wall 12. The work table 15 may not be provided.

<B> Curved Wall The curved wall 2 is formed by curving upward from the back wall 12.
The wall extends to the end of the top plate 11 on the opening 14 side. The curved wall 2 may be formed by a combination of straight lines.

<C> Air-Blowing Pipe A predetermined length of air-blowing pipe 3 is attached to the upper end of the curved wall 3. The air outlet pipe 3 has a plurality of outlets 31 for blowing air obliquely downward.

<D> Blower The blower 4 communicates with the back side of the air blow-out pipe 3, and blows air from the blow-out port 31 by sending air from the blower 4 under pressure, and the air curtain is blown. A can be formed.

<E> Air-suction port Air-suction ports 5 are respectively opened at predetermined opposing positions of the side walls 13 on both sides. A duct 51 is connected to the air suction port 5, and draws the generated air curtain A toward the curved wall 2 to generate a negative pressure for forming the vortex B.

<F> Exposure-preventing air-blowing device The contaminated air that has become the vortex B sucked by the air-suction port 51 is purified by the exposure-preventing air-blowing device 6 through the duct 51, It is blown toward the vicinity of the worker's head (head top, occipital region, face, etc.) located on the front surface of the curved wall 2 and merged with the vortex B to form a circulation system.

As an example of this circulation system, first,
A primary purification device 61 for purifying coarse particles in contaminated air is communicated via a duct 51.

Next, a fan 62 for sucking contaminated air and a filter 63 for purifying finer particles are provided.

Then, the primary purification device 61, the fan 62,
An air supply pipe 64 communicates between the filters 63, and the tip of the filter 63 projects upward or backward from above the worker so that air can be blown out near the head of the worker.

The structure of the outlet section of the air supply pipe 64 is as follows.
For example, a first outlet 65a for directly injecting the direct injection air-C and a second outlet 65b for not directly injecting the air are provided near the head of the worker.

The second outlet 65b is a portion that blows out detour airs D and E in order to adjust the blowout amount of the direct injection air-C.

The reason for adjusting the blowing amount of the direct injection air-C is as follows.
This is because if the blowing amount and speed of the directly injected air are too large, the swirl B may not be formed properly due to the influence. As means for solving this, the detour air-D, E whose blowing speed is slowed down by detouring is blown out.

The detour air-D travels around a relatively close detour and joins the vortex B from near the back of the worker to form a detour air-D.
E is a flow that goes around a detour farther than it and joins the vortex B from behind the operator.

The first outlet 65a, the second outlet 65
b includes fins 66a capable of changing the injection direction,
66b may be provided.

It is also conceivable to change the injection direction by forming the projecting portion of the air supply pipe 64 so as to be able to expand and contract in the axial direction.

<G> Adjustment of Air Blowing and Suction The welding rod used in the welding operation has a sealing gas jetted from a tip thereof at a predetermined speed (for example, 0.2 m / sec). Therefore, an air flow that breaks the gas seal formed by this seal gas (0.2 m / sec in the above example)
When the airflow having the above speed blows on the tip of the welding rod, a welding defect may be generated. In this regard,
It is also pointed out in the Fifth Dust Damage Prevention Comprehensive Measures Promotion Guidelines prepared by the Ministry of Labor.

Therefore, in the apparatus of the present invention, it is necessary to adjust the blowing and suction of air so as not to cause the above-mentioned welding defects. That is, by adjusting the amount and speed of air blown from the air-blow-off pipe 3 and the amount and speed of suction by the air-suction port 5, the position, size (diameter of swirl) and swirling speed of the vortex B can be adjusted. 15 is set so as not to affect the welding point.

Further, in addition to the above set conditions of the eddy current B,
By adjusting the blowout ratio, blowout amount and speed, and blowout direction of the direct injection air-C, bypass air-D, and E, which are circulating flows,
5 Set so as not to affect the welding point on the top. By satisfying the above conditions, it is possible to prevent the occurrence of welding defects and to perform a good welding operation.

[0026]

Since the present invention has been described above,
The following effects can be obtained. <B> By blowing out the exposure prevention air near the worker's head, the contaminated air near the worker's mouth can be blown off in the vortex direction. Therefore, it is possible to reduce the exposure concentration (near the mouth) of the worker, and it is possible to effectively prevent dust damage through improvement of the working environment.

<B> Contaminated air having a relatively high concentration floats in a closed factory. In the case of a conventional local exhaust system using a vortex, the contaminated air is caught in the vortex and exhausted together. It had been. For this reason, the filter of the purification device is correspondingly burdened, which shortens the life of the filter.

However, according to the present invention, it is possible to prevent the contaminated floating air in the room from being entrained in the vortex by the sealing effect of the air curtain formed by blowing out the exposure preventing air. Therefore, the burden on the filter of the purification device can be reduced, and the life of the filter can be extended, which is economical.

<C> Conventionally, a push-pull type ventilation system in which air is blown from behind and obliquely behind a worker to prevent exposure and draws contaminated air directly from an exhaust hood in front of a workbench. The device is present. In the case of this device, the air blown from behind passes directly through the welding point, so that some types of welding operations may cause welding defects as described above.

On the other hand, the present invention relates to an exposure preventing air
Is swirled before reaching the welding point,
There is no direct passage as in the conventional device. Therefore, the apparatus of the present invention enables a better welding operation than the conventional apparatus.

Further, according to the present invention, since the exposure-preventing air has little effect on the welding point, it is possible to blow out stronger air to the worker's head than in the conventional apparatus. for that reason,
The effect of preventing workers from being exposed can be further enhanced.

Further, in the conventional apparatus, a special air-blowing device must be installed separately from the ventilation device behind or above the worker, and thus a large installation space is required. However, if a circulation type exhaust device as in the present invention is adopted, a large installation space becomes unnecessary.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

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

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-38541 (JP, A) JP-A-54-116354 (JP, A) JP-A-63-268574 (JP, A) 213932 (JP, A) JP-A-3-275282 (JP, A) JP-A-62-146585 (JP, U) JP-A-56-100280 (JP, U) JP-B 3-79618 (JP, B2) (58) Field surveyed (Int. Cl. ⁷ , DB name) B23K 9/32 B23K 37/08

Claims (2)

(57) [Claims] 1. A local exhaust device that blows air to the front surface of a curved wall and sucks air toward the curved wall to form a vortex, and sucks and exhausts contaminated air by the vortex. Directly near the head of the worker located at
Blows out direct injection air and controls the amount of direct injection air
Air, and in addition to the set conditions of the vortex , the blowout ratio, blowout amount, and blowout of the direct injection air and the bypass air
The local exhaust device is characterized in that the outlet speed and the blowing direction are adjusted so that the direct injection air and the bypass air join the vortex without passing through a range that hinders the work. 2. A local exhaust device which blows air to the front surface of a curved wall and sucks air toward the curved wall to form a vortex, and sucks and exhausts contaminated air by the vortex. And the purified air- directly near the worker's head located in front of the curved wall ,
In addition to blowing out direct injection air, the amount of direct injection air
It is also blown out as bypass air for adjustment, and in addition to the set conditions of the vortex , the blowout ratio, blowout amount, and blowout of the direct injection air and bypass air
The local exhaust device is characterized in that the outlet speed and the blowing direction are adjusted so that the direct injection air and the bypass air join the vortex without passing through a range that hinders the work.