Dearating Viscous Fluid

[Leo1]

At our plant, we are batch processing liquid polymer from a loss-in-weight feeder to a vessel below. The material is pumped from a loss-in-weight feeder through a 2" pipe through a check valve to the vessel. Under normal circumstances the pipe is totally filled with the liquid polymer and is pumped into the vessel. This is essentially the weighed material. Sometimes we get air entrapped in the pipe from changing the strainer this causes light weightments to the vessel below. Is their any equipment or valving that will automically bleed the air out the piping?