Calculating Force on Springs in a Vacuum Chamber

[hermano]

Hi,

I have a bottom plate resting on a table (see figure in attachment).
On top of this bottom plate is are series of springs and on top of it rests a top plate.
Between the bottom and top plate (inside the springs) is a seal to create a vacuum chamber.
Question: what is the total force acting on the springs if the vacuum chamber (inside the seals) is 1 x 1 meter and the vacuum pressure is 1 mbar (atmospheric pressure outside)? Is this 101 kN (pressure difference between the atmospheric pressure on top of the top plate and inside the vacuum chamber ) or 202 kN (pressure difference between the atmospheric pressure on top of the top plate and inside the vacuum chamber AND pressure difference between the atmospheric pressure under the bottom plate and inside the vacuum chamber)?

 

[JBA]

Your first value is correct