Three Attention Points in the Design of Sandblasting Room

When we design the sandblasting room, we need to pay special attention to the following three points, because they are related to the dust removal effect of the sandblasting room:

1. Three kinds of abrasives commonly used in the sandblasting room and dust quantity 

There are three kinds of abrasives we use normally: steel shot, yellow sand, and brown corundum.

The amount of dust produced by the three kinds of abrasives during spraying is different. The dust amount of steel shot is the smallest, the dust amount of yellow sand is the largest, and brown corundum belongs to the middle. Because the dust amount of these three abrasives is different, in the same volume, the equipment and air volume they need is also different.

2. Two ways of calculating air volume in sandblasting room design

Therefore, for sandblasting room design, there are two ways to calculate the air volume:

(1) The air change rate, that is to say, the volume of the whole sandblasting room is estimated according to its dust concentration, or calculate the number of times it needs to change per minute by formula so that we can get the air change rate and the whole air volume.

Normally the air change rate of yellow sand is about 150 to 200 times per hour, while that of steel shot is about 120 to 150 times per hour, and that of brown corundum is about 150 times per hour.

(2) The calculation of the cross-sectional area ensures that the air volume can be calculated by the dust absorption in the sandblasting room. We all know that the dust in the sandblasting room does not need excessive negative pressure, while the most important thing is to ensure the dust not spill out to the door. It only needs to produce a certain negative pressure in the sandblasting room, so that the dust can naturally settle in the sandblasting room or in the suction outlet, which can discharge the dust to the outside and make it enter the dust collector for filtration.

We usually calculate the cross-sectional area with length * height. Based on the cross-sectional area calculated by length * height, we can use the common calculation formula again to get the air volume. However, we should pay attention to the selection of its filtration velocity. We can take 0.2 or 0.3 at least to ensure that the air volume is within a reasonable range.

3. Notes for the selection of additional tuyere

Here is a note about the additional tuyere. Actually there are regulations on additional tuyere: The additional tuyere should not be too small. If the additional tuyere is too small, the air inside can not get fresh air change, so the air suction effect inside will become very poor.

If the additional tuyere is too large, the dust will spill out. This size of additional tuyere needs to be calculated. If we use an axial flow fan to make up the air inside the sandblasting room, we should pay attention to the tangential direction of the wind to ensure the dust will not rotate in the sandblasting room and can be discharged.