Noise protection during thermal spraying

From the technical and management aspects to control, can reduce the noise, or reduce the exposure time in the noise environment.

A Technical controls include:

a) Redesign equipment

b) Re-select the installation location of the devise

c) Change the operating conditions of the spray gun

d) Isolate audio equipment and set up separate operation room

e) Provide ear protectors for the operator

B Under administrative control, people can plan and schedule time to reduce exposure to noise.

Redesign equipment:

In addition, the installation of silencers on thermal spraying equipment has proved impractical and ineffective. Since the noise is scattered and reflected around the soundproof board, a simple soundproof board installed between the gun and the operator standing near the gun will not work. Specially designed sound absorbing material can reduce the nearby area by 5 db. Placing such materials on a wall or on a hanging soundproof board is an effective investment in reducing noise in the immediate area, but not very helpful to the operator at close range.

Re-select the installation location of the devise:

The greater the distance from the noise source, the lower the sound pressure level. In a large room with a sound reflection surface, the sound pressure level can be reduced by 6 db every two times the distance. It is known from practice that the noise level decreases slightly as the distance increases.

Change the operating conditions of the spray gun:

The noise level of the thermal spray gun can be reduced by 3-5 db by reducing the spray gun parameters and lower spraying rate. By reducing the gas flow and air flow, the noise level of the gun can be reduced by 3-5 db. Less heat leads to a lower rate of spraying and results in a coating that is less dense and soft and has a larger micro-structure than the coating under standard spraying conditions.

For plasma spraying, the noise can be reduced by reducing the current, of course, the spray rate needs to be reduced accordingly. Reducing gas flow also reduces noise and, because of the reduced heat available, reduces the quality of the coating.

For arc spraying, noise can be reduced by reducing the current (spraying rate) or the flow of atomized compressed air, or both. If both are reduced, the effect on coating properties is similar to that described above. If the spraying rate is reduced, and the atomized air flow is not reduced, the coating in the spraying state has a fine structure, and the coating is dense, for some materials, the coating contains more oxides.

Typical noise level of thermal spraying equipment

Equipment  

Decibel (DBA) 

Oxyacetylene gun 

89-111

 Ordinary arc gun

111-116

Supersonic arc gun

114-125

Plasma gun

128-134

Typical sandblasting equipment

80-85

Typical exhaust equipment

Less than 90

 

 

Isolate audio equipment and set up separate operation room:

Now the standard sound-absorbing sealed spraying operation room, thermal spraying operation is completely carried out in the isolation room, the noise transmission has been greatly limited.

Provide ear protectors for the operator:

When the sound insulation condition in the operation room is insufficient, it is recommended to use silent earphones and sound insulation earplugs to protect the hearing of operators and reduce the noise by 10db-20db.

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