US Patent 11511462 Foam-in-bag systems and components thereof

A system includes a dip tube, a feed line, and a check valve. The dip tube is inserted through an opening in a source of chemical precursor and into the chemical precursor in the source. A portion of the feed line is located in the dip tube. The feed line passes out of the dip tube. The chemical precursor is capable of flowing out of the source through the feed line in a downstream direction. The check valve is located in the portion of the feed line in the dip tube. The check valve permits the chemical precursor to pass substantially only in the downstream direction. The feed line is coupled to a transfer pump that draws the chemical precursor out of the source through the portion of the feed line in the dip tube.