SANDY CURTH
about
class site
Foam Generator
The foam generation system uses compressed air to push
a foaming agent/ water through a pressurized chamber
filled with steel wool.
System Components
The foam agent reservoir and foaming chamber are made
from pressure rated PVC and standard PVC plumbing caps.
The air, foam agent and foam lines are vinyl 1/4" and 1/2"
vinyl tubing meeting standard NPT push to connect fittings.
Foaming agents
There are many foaming agents. Generally they are made
up of a concentrated surfactant. For the purposed of this
experiment we will use two agents, one industrial (FM-160)
and one more open source friendly (Suave shampoo).
Foam control
For our first test we will use manually adjusted valves and
regulators to find the proper pressure and output flow for
mixing with foam with earthen material.
In v2 of the system we will use a solenoid valve at the foam
output where it meets the auger system for more precise
control of the mixing process.
References
[1]D. Falliano, L. Restuccia, and E. Gugliandolo, “A simple optimized foam generator and a study
on peculiar aspects concerning foams and foamed concrete,” Construction and Building Materials,
vol. 268, p. 121101, Jan. 2021, doi: 10.1016/j.conbuildmat.2020.121101.
[2]E. Lorenceau, Y. Y. C. Sang, R. Höhler, and S. Cohen-Addad, “A high rate flow-focusing foam
generator,” Physics of Fluids, vol. 18, no. 9, p. 097103, Sep. 2006, doi: 10.1063/1.2353799.
Foam Generator v1
03/29/21
Assembled primarily with off the shelf Schedule 40 PVC pipe
parts, this first test effectively produced foam. Properly tapping and applying thread tape is key to building a leak free system. To simplify the assembly all of our connections are 1/4" NPT push to connect fittings.
We used a generic Suave shampoo as the foaming agent for the
first test with relatively consistent results. The clear limitation of
the test was a lack of accurate flow control for all aspects of the
system. We could use a regulator manifold to accurately control
pressure in the foaming chamber and reservoir. Generally we
were testing around 60 psi which is way too high for the actual
application.
04/12/21
A second set of tests at 30psi resulted in much more consistent foam delivery.
Next steps on the foam generator are dependent on the completion of a robust extruder/ auger system.