Patent ID: 6537033
Filing Date: 2003-03-25
Classification: A01J,F04B,Y10S

Abstract:
An open loop control apparatus for a vacuum system for providing vacuum stability within a predetermined range of vacuum levels comprisinga vacuum regulator having a diaphragm including a valve member having a valve opening which changes position as a function of vacuum levels for controllably bleeding air into the vacuum system to adjust the vacuum level within a predetermined range of vacuum levels; a transducer operatively coupled to said diaphragm for producing an output signal which represents an instantaneous position of the valve opening and wherein said transducer is a low voltage digital transducer; and a control device having a pair of inputs and an output, said control device having applied to one of said pair of inputs a set point signal representing a programmed vacuum level for the vacuum system and having applied to the other of said pair of inputs the output signal from said transducer representing an instantaneous position of the diaphragm, said control device producing on its output a control signal for controlling speed of a variable speed motor which drives a vacuum pump at various speeds to maintain the vacuum level within a predetermined range of vacuum levels.