11 Aug How to Spot Blockages in Pneumatic Conveying Systems
Partial restrictions in Pneumatic Conveying Systems normally do not appear without any warning. This article lists some of the early warning signs and thus enables actions to prevent a partial restriction becoming a total shutdown.
Sudden Drop or Spike in Line Pressure
A sharp drop in line pressure (indicated by the corresponding change in the reading on the pressure gauge) could indicate that a blockage has occurred, with resulting bypass of the material by the air; a sharp rise in line pressure may be an early warning sign of a restriction building up in the line.
Irregular or Pulsing Material Flow at Discharge
Material flowing through the pneumatic conveying line in steady flow should discharge smoothly and consistently from the end of the line. When material is discharged in irregular surges or even stops for periods then there is a problem somewhere upstream of the blockage in the line.
Unusual Motor Load or Fan Noise
The fan or motor may indicate that a restriction is building in the conveying line. A change in pitch of fan noise can often go unnoticed until it is reported by another person. It is therefore wise to cross check the instrument readings with any reported changes in fan noise.
Settling at Bends and Low Points
Pneumatic conveying, like those found at www.aptech.uk.com/pneumatic-conveying-systems.requires that the air velocity is high enough to hold the material in suspension. Thus when the velocity drops for any reason, the material will settle at bends and low points in the conveying system first.
Rising Cycle Times or Falling Throughput
However, if a batch is taking longer than normal to complete, then the material is being conveyed against a restriction. As mentioned previously, the build-up of pressure due to blockages in pneumatic conveying systems can cause a number of problems, increasing the risk of injury in the workplace. Therefore, falling throughput needs to be addressed as a safety issue as well as a productivity issue.
By recognising these warning signs you can prevent partial blockages developing into complete shutdowns and thereby keep production running safely and for the shortest possible time.