Often largely ignored or diminished in its importance, the separator system is a very crucial component of the blast machine. The reasons they are looked after less are usually because they are difficult to get to, they are sometimes very high off the ground, and it’s often hot and dusty up there.
This may be, however, neglecting the separator is the perfect recipe for:
- premature wear of the other parts of the machine
- longer cleaning cycles
- improper cleaning.
Properly maintaining the separator will help you achieve maximum efficiency of your blast machine.
Before and after a well-maintained separator
The separator system is comprised of several components. After the abrasive is thrown at the parts being blasted, it will be carried back up, along with the dust and slag created from the blasting, via the reclaim system (to be presented in a future article).
At the top of the reclaim system, begins the separation process. A rotating screw carries the abrasive across a trough and through a rotating screen. This rotary screen separates the large debris from the mix and discards it out of the system through a debris chute. The abrasive that falls through the screen then goes to the air wash.
There, the abrasive is spread across the full length of the separator opening and creates a curtain.
There, the abrasive is spread across the full length of the separator opening and creates a curtain.
Rotary screen that needs cleaning
Air is pulled through this curtain of abrasive and it forces the lighter particles (fine abrasive, dust, slag, etc.) to separate and travel toward the back of the curtain. From there, a scalping bar divides it into two chambers. The heavier abrasive that is still useful for blasting, falls into the hopper to be sent to the wheels again. The lighter of the abrasive (dust, fines, slag, etc.) goes into the expansion chamber where it then either falls into the discard or is pulled into the dust collector. The point of this division can be adjusted according to the application and abrasive being used. This is done by a combination of settings within the separator. It is important to find the proper balance of air flow and separator settings so that particles that can wear or damage the machine (sand, fines, etc.) are removed from the machine, but also so that you’re not removing good abrasive from the machine, causing a monetary loss.
Maintaining the abrasive curtain in the separator is key to ensuring it performs properly. When gaps and blockages occur, air will take the path of least resistance and circumvent the abrasive, reducing the cleanliness of the operating mix going back to the wheels. This is how premature wear to the wheels and wear parts of the machine occurs.
The Separator in Action!
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| Major blockages | Proper abrasive curtain |
Written by :
Chris Prouty
Technical Service Advisor, NAO
Chris.Prouty@wabrasives.com
(682) 300-1885