In this video the material flows with high speed trough the neckpiece.
To do a better test there should be a feeder under the neckpiece, and a hopper on top of the neckpiece.
Then the neckpiece is completely full of material, and the main material flows with ‘slow’ speed.
Then the test is simulating the real process, and that is a better test for the bridging and blocking.
For this application the NST90 with single insert could be to just to small.
It is more save to use a HO-Neckpiece with a small single insert ( see attachment)
This because of the shape or the material, and there are also pieces of about 17mm long.
With the ‘HO-Neckpiece with a small single insert’ the opening is big enough to prevent blocking.