Patent ID: 6953315

Claim:
An apparatus for controlling the flow of a process material, comprising: (a) a first chamber having a rigid outer shell, the first chamber being divided into first and second regions by a flexible boundary, the second region being filled with a non-compressible fluid; (b) a second chamber having a rigid outer shell, the second chamber being divided into first and second regions by a flexible boundary, the second region being filled with a high pressure non-compressible fluid; (c) an inlet flow control device arranged to provide fluid communication between a material input line and alternately the first region of the first chamber and the first region of the second chamber; (d) an outlet flow control device arranged to provide fluid communication between a material output line and alternately the first region of the second chamber and the first region of the first chamber; and (e) a chamber control device arranged to provide fluid communication between the second region of the first chamber and the second region of the second chamber; (f) wherein the apparatus is such that it regulates the high pressure input line so as to alternately discharge process material from each of said first regions.