I think instead of animating the blobmesh, I'd probably animate the material. Because trying to create enough particles for sand with just pflow would be painfully slow if at all. Map some images of sand onto your blobmesh and then animate that turning to glass.
For the tube part, I'd switch to geometry instead of using the particles. Just use the particles for the part before it enters the tube. Use the geometry for when it's in the tube and you can either use an animated Slice modifier or a Volume Select modifier with a DeleteMesh on top of it to reveal the geometry.
3ds Max 2009 SP1, 2010 SP1
Maya 2012
Windows 7 Professional 64-bit
Dual Intel Xeon E5520, 6 GB Ram
NVIDIA GeForce GTX 460 OC