Control device for a rotary valve-controlled jigging machine

Apparatus for controlling a rotary valve jigging machine which has an air chamber disposed in a separating liquid below a jigging screen and air is supplied to and exhausted from the air chamber through inlet and outlet air lines, respectively, comprising:

• sensing means in the air chamber for producing an electrical signal corresponding to the stroke of the liquid pulsations;
• an outlet throttling valve in said outlet air line;
• and control means connected between said sensing means and said throttling valve for adjusting said throttling valve in response to the electrical signal being outside predetermined limits, said control means comprising first and second means connected to said sensing means and responsive to the magnitude of said electrical signal to produce respective first and second signals when said electrical signal transgresses respective predetermined upper and lower threshold values, and electrical servomechanism means connected between said first and second means and said throttling valve for adjusting said throttling valve in response to said first and second signals.