Single plug blow tank systems
With some materials the plug of material that is conveyed will be accelerated along the length of the system pipeline. If there is no check on the volumetric flow rate of air supplied, additional air and hence energy will be expended unnecessarily on the mater- ial. If the volumetric flow rate of air needs to be controlled a choked flow nozzle or orifice plate can be used in the air supply line.
When a plug of material is discharged from a pipeline at a high pressure, a large vol- ume of pressurized air is released, particularly if it is a long pipeline. A certain amount of material is almost certain to be left in the pipeline. This will tail off the end of the plug being conveyed, to be swept up by the front of the next plug. The high pressure air in the pipeline will suddenly be vented from the end of the pipeline when the plug is discharged. The venting air, which can reach an exceptionally high velocity, will pick up deposited material and cause severe erosion problems if the material is abrasive.