Blowing Sand
bbhaskar,
6 t/h would seem to be on the low side for a 5” system 80 meters long. On the other hand, 15 t/h would be a stretch for a straight 5” system, straight meaning that the conveying pipe is not stepped. 12 t/h should be possible without piping modifications, 18 to 20 t/h should be possible by stepping the conveying pipe to 6”.
Efficient blow tank operation is based on using all of the available supply pressure. The air supply to the blow tank system is normally in two parts, a part of it going directly to the conveying line, and a part of it going directly to the blow tank. That portion going to the blow tank effectively controls the conveying rate. The general idea is to increase the feed rate, and thereby the conveying pressure, until the conveying pressure approaches that of the air supply.
Your thread makes no mention of the amount of conveying gas that is used. But the fact that your dust extraction system is overwhelmed suggests that the total conveying flow is greater than the system was designed for.
Reduce the amount of air going to the pipeline, which should improve the dust extraction performance, and increase the amount of air going to the blow tank, which should increase the conveying rate. It is possible that over a decade of operation that these flows have gotten out of adjustment. Readjusting the air flows should result in a rise in operating pressure. Allow it to rise to 90% of the supply pressure for safe operation.
Best regards,
Dennis Hauch ■
Re: Densveyor 8/8 Causing Bottleneck
Please check the conveying line, especially the bends for any air leakage due to erosion. Erosion is quite common when conveying this material. Air leakage reduces the conveying velocity.
In dense phase conveying, increasing the air velocity will increase the solids conveying rates.
Our Company has special expertise in conveying of cement and sand. Please visit our web page. We will be glad to work with you to give you proven solutions to your problem.
Amrit Agarwal
Pneumatic Conveying Consultants
www.powderandbulk.com/pcc ■
Densveyor 8/8 causing bottleneck
A Macawber Densveyor 8/8 with a 5" pipeline installed a decade ago & used for transporting sand over 80 M pipeline( 70 Hoizontal & 10 Vertical)with 6 bends is transporting only 6 T per hour. Is this the rated capacity? t takes 2-3 minutes for a batch to be delivered before next cycle starts. Air pressure is 5 Kg/cm2. We need output of 15 T per hour. How do we enhance this capacity? Is the pipe size sufficient? Do we need to replace the transporter? Any boosters available?
Also, the exhaust pipeline at the delivery end silo connected to a 3 HP extraction system gets choked every 15 days with coarse particles.
Suggestions and solutions from experts urgently solicited. ■