FK Pump/Vane compressor

Not having a check valve in the discharge line.

Have you a check valve on discharge line?

The check valve on the discharge line is ok. We are producing cement. After a bagfilter the cement goes to an airslide and then to fk pump hopper and then to Silo. We do not experience overload at FK pump its just that the cement comes out from the airslide and the flapper valve at the bagfilter starts to get blocked. Its like air is pushing the cement back at the airslide. Airslide is clear and no build up at the air compartment.