I am making a QC testing station that tests the bursting pressure of polyethylene tubing (.5" Dia, ~.1" Wall thickness) I need a pump that will gradually increase the pressure from about 30 psi to 300 psi over a period of time of a minimum of about 1 minute. All I have found so far are electro hydrostatic test pumps. The problem with these is that they will jump from 30 to 250 psi in about half a second.