Degassing - Getting the air out
The process of degassing is used in a variety of end applications and for a
purposes. HyVac vacuum pumps are often used to degas epoxies, silicones, rubbers,
plaster of Paris and a wide variety of viscous materials. If a user is looking to
degas a compound they usually put it in a container that can withstand a vacuum pressure
put a lid on it and pull a vacuum to roughly 29" Hg vacuum. HyVac single stage
pumps are very good choices for this application. They will reach 29.9" mercury
vacuum and for the most part, fully degas a compound. Consideration in pump selection needs
to be given to the tightness of the system, size of the system and cure rate of the
material to be degassed. Some applications need to happen fast, some can take time.
We can size pumps for your application but need the following
1. Size of air space to be evacuated. Your tank
less how much material in it for degassing.
2. Starting pressure usually atmospheric.
3. Ending pressure usually 29" Hg thereabouts
4. Time for process to take place in minutes
5. Other mitigating factors.
a. Solvents or water
coming off the mix.
The process is required when compounds are mixed or agitated in preparation and air
becomes entrained in the end product. By putting the compound under vacuum the air
that is entrained expands as the pressure reduces allowing the entrained air to break the
surface of the compound and be released. The pump then ejects it from
the system (compound).
Care should be taken in the application to try and identify those items in the mix with
a vapor pressure that could also be pumped under vacuum. These kinds of products
should be trapped out of the system before they reach the vacuum pump, to assure a long
trouble free pump life. Typical byproducts that can cause difficulties can be
either solvents or water.