i don't get it

first, is the pict correct? , i guest not.
the pict show condition/position after applying force  FR or FL or BOTH,

Appling for example a strong spring that pulls the two pistons togheter,we have a bigger pression on the left chamber,so if the hose can flect the left piston will move right pulled by the right piston, cause on it is acting a superior pressure respect the left...clear now?

PS. Your pic is correct,same of mine... isn't corrected the relation...

if we push/pull pistons at the same time, with same force,
of course, we get the difference of pressure,
and if we add more and more then the hose/device will explode.
in other words, i don't understand .

sorry.
better wait for an expert.

Once we put a strong spring,we don't need nothing more... I think the hose will flect moving righ,then the water pass throug a small connection hose from left chamber to right chamber.now the water leave left chamber is equal that goes to right chamber moving the piston. The two pistons are "fixed" they will move right togheter without loosing potential of the spring... so if the flexible hose flets...

Need help