Dennis wrote:


Dumb question guys - why not place the bagged food inside a pressureised
chamber with the mouth of the bag exiting from a gap/slit in the pressure
chamber?

Applying air pressure inside the chamber would force excess air etc from the
bag which could then be sealed.


/--------------------\
/ \
========##BAGofFOOD## ==== air press in.
\ /
\--------------------/

^
^
^
heat
seal
here



OK I can answe that. If you were to pressurise the outside of the bag
everything inside the bag would try to escape, including the stuff you
wanted to keep in the bag.

Think about a kid stepping on a packet of ketchup.

Roger Shoaf