Using a Line Vac with a Slide Gate

This week customers have asked a few questions about EXAIR Line Vacs. I wanted to explain a few tips and tricks for using this product to achieve maximum performance. .

Here is a link to an EXAIR Line Vac Video, if you would like to see it in action.

EXAIR’s Line Vacs are compact in-line conveyors that operate on compressed air. Their flexible designs can move large amounts of materials like plastic pellets, small component parts, or trim and waste materials. The Heavy Duty Line Vac is capable of moving more volume of material and much heavier material than the standard Line Vac and is also resistant to abrasion from materials like garnet, ground glass and tumbling media. The Line Vac is great for vacuuming out product from an open hopper or manual clean up operations.

Yesterday, I had a customer who wanted to use a Line Vac to convey products out of a silo.  He wanted to move 10-15 pounds of material every 2 hours. The Line Vac should have worked for this application, but my customer had a problem.  The Line Vac would move a small amount of the product when the system first started, but would not flow all of the product that was required.  The customer was using a slide gate to meter out the correct amount of product that the Line Vac need to convey.  This is a good way to meter the Line Vac to only convey what is required for the application. The problem is that the slide gate would also prevent any airflow moving from the silo into the Line Vac stream, and airflow is what moves material through a Line Vac. The Line Vac was only pulling a vacuum on the tube that connected to the slide gate, but it could not entrain any air to move the product.

By closing the slide gate after metering out the product the customer was removing all the air from their line. Air flow must move by the material and drag the material along in order to move it. With the slide gate closed any air is prevented from moving across the material.

I suggested the customer to add some air holes (breather holes) into the intake hose just after the slide gate.  This would allow the correct amount of product to drop through the slide gate. The slide gate would then close and the Line Vac would run. The holes in the intake hose allowed the Line Vac to entrain air behind the material and convey it to its final destination.  The Line Vac was able to convey the 10-15 pounds of material in less than 5 minutes once it had a source of air to entrain.

Dave Woerner
Application Engineer
DaveWoerner@EXAIR.com
@EXAIR_DW