Define force balance principle

Question

Describe briefly the term force balance principle? And also write down its merits?

Answer 1

Force balance principle : A controller that produces an output signal through opposing torque. The input force is exerted on the input bellows that shifts the beam. This crackles nozzle back pressure. The nozzle back pressure is sensed through the balancing bellows that takes the beam to balance. The baffle movement is extremely less about 0.002 for full scale output.

Merits:

i) Baffle movement is negligible
ii) Frictional losses are less   
iii) Moving parts are fewer.