Foam has been a traditional problem for most Dry Cell
designs. It happens for several reasons. Some I can explain, and some I
can not.
The dry cell does not have any air space inside, when it is off
(not operating). This is because the weight of the water in the
water tank, or bubbler, completely fills the inside of the cell, and
even comes out the top hose that the escaping HHO gas uses. Now,
when you apply power to the dry cell, the HHO gas rises to the top
of the cell and escapes through the top barb fitting and out the
tube, and makes its way up to the bubbler/water tank. As more HHO is
produced, it pushes the water out of the tube and pushes down on the
water level inside the cell. It does this because of backpressure
caused by the weight of the water in the bubbler/water tank. The
water level will try to stabilize just below the top barb hose
fitting. When that happens, there will be a lot of turbulence caused
by the rising bubbles. That causes the foaming. The foam is actually
a mass of bubbles. Bubbles are made up of the gases covered by a
water membrane. The bubbles get pushed out the cell, and travel up
to the bubbler/water tank. Now they make their way to the surface;
on the way, most of the foam gets eliminated. However, the
turbulence on the surface of the bubbler/water tank causes more
foam.
Backpressure is one way to reduce foaming. It does not take
much. Installing a check valve, or a flash arrestor will put a
little backpressure on the bubbler/water tank. That pressure will
push down on the bubbles (foam) causing them to dissipate. Lowering
the bubbler - also causes backpressure if it causes the output gases
to travel down, instead of up.
Vacuum pressure is another way to reduce foaming. It pulls the
heavier Oxygen bubbles out of the bubbler/water tank. The oxygen
bubbles are causing the foam. The Hydrogen bubbles are traveling 45
miles per hour - towards the engine. They don't hang around, but
some of them get trapped in the foam.
Strong Electrolyte mixtures can cause foaming. Water will
naturally foam slightly, but the contents of the water has more to
do with foaming than anything else. What ever is in the water, will
be in the bubble membrane.
The videos below, are using Vinegar as a de-foaming agent. They
are passing the HHO gas through a vinegar bath. I am totally against
that. The bubbles exiting the vinegar bath contain what? You guessed
it, Vinegar. That is going to cause a problem. The vinegar will get
into the bubbler/water tank, the bubbler/water tank cycles the water
back to the Cell, and that is going to cause a nasty brown scum to
collect on the electrodes of the Cell. You can witness this in the
second video below.
Most Dry Cells need bubblers, and bubblers need lots of freeboard.
Freeboard is the amount of space above the water. You need enough
space for the foam to collect and dissipate. My tube Wet Cell design
does not need a bubbler, because it has 5 inches of Freeboard;
something to think about.
Some types of rubber gaskets cause foaming. Natural rubber
supposedly does not cause foaming.
The rubber must be appropriate for alkaline use or it will
contaminate the electrolyte with organic acids, making soap with
the KOH or NaOH. Carefully check the characteristics of your
rubber type, EPDM rubber works great.
Ethylene Propylene Diene Monomer, provides verygood
resistance to weathering, ozone and UV exposure.
It is highly recommended for applications where the elastomer
will have excessive exposure to the environment. EPDM makes agreat
hanger flap, roof pad, or outdoor industrial rubber curtain.
It provides very good chemical resistance and dynamic
properties. E.P.D.M. blended material is considered a non-oil
resistant material.
It is
well known that when KOH and NaOH are mixed with oil it makes Soap.
It is very important to clean the oil out of everything the water
touches. That includes the cell, the barb fittings, the hoses, flash
arrestors, bubblers, pumps, flow meters, check valves; everything.
Wash these parts inside and out with a mild dish soap and rinse
really good. That should eliminate the lubricants used in the
molding process.
Foaming agents? If you know of one that works, one that does not
cause problems with the plate surface, please let me know; I will
post it here.
Dimethylpolysiloxane (anti-foaming agent)
Mylanta
Spa anti-foam
Video provided by Bruce Energetics:
Video provided by Bruce Energetics:
Spa
de-foamer
We do not know what it is that he puts
in the water. It does seem to eliminate the foam. But, the water in the
bubbler is re-filling the cell. That water may contaminate the metal
plates. Only testing will tell if this works long term.
A
comment from the above video's YouTube page: The Spa de-foamer can
be costly. You really don't need a 20 oz bottle. Instead, go
to the
baby aisle or antacid dept in the Pharmacy area in Wal-Mart and buy
any liquid GASX type product that has Simethicone. Google it to
confirm. Simethicone is used in some detergents when foaming is
unwanted. This is basically the same stuff for much less.
