Weigh hopper

[ash9144]

We have a solids weighing hopper. When the unit is being started up we purge with nitrogen to remove oxygen. When the pressure increases 0.5-1 in H2O we are seeing the weight in the hopper increase by roughly 1000 lbs. The volume is small roughly 400 cu ft so it isn't the weight of the nitrogen and it has never been noticed before. If we bleed the pressure back off the weight drops so there is not something else bleeding into the hopper at the same time. The only theory I've come up with is the hopper is out of balance and the internal pressure pushes on the weigh cells (4 cells) unevenly causing the weight readings. Anybody got any other thoughts or experiences on the matter?

 

[Chance17]

A simple guess -- maybe you have some rigid pipe connected to the bin.

 

[ash9144]

Nothing rigid. All flex.

 

[Chemerdjb2]

another though, are you sure of your pressure readings, could they be off and you are actually pressurizing more than you think.

 

[europipe]

Maybe your flex pushes down under pressure?