Lack of Mixing - Injection Quill w Static Mixer

[maggief]

We have taken an old polyester resin composite casting machine and retrofitted it for a new location. A Polyester resin/solids mixture is pumped via piston to a mixing head and MEKP catalyst is also pumped into the head via piston pump. The MEKP is introduced via 10 gauge syringe in center of pipe with flow in same direction as resin. The syringe introduction is just prior (less than 0.25") from the first static mixer element. Viscosities are 250-450cp for the resin and about 1cp for MEKP.
In the old location the system mixed the two components well enough, now we have hot spots and soft spots in cured parts from the catalyst not being mixed in well enough.

Any ideas on priority as to where to look?
1) increased length of tubing from pump
2) couplings in the tubing
3) position/orientation of quill
4) static mixer is now at 45 degrees from vertical, it was vertical before.

 

[unclesyd]

We were never successful using small diameter quills in polymer streams, especially on shear sensitive materials.

you might want to take a look at this approach. We had to use this on several polymers to get the proper mixing.

http://www.komax.com/det-ppparaflow.html