Patent ID: 7059171

Claim:
An industrial process control system for controlling at least one parameter of an industrial fluid process having at least one fluid flowing within a pipe, said system comprising: a density meter disposed on said pipe, said density meter comprising: a first sound speed meter configured to detect acoustic pressure signals the first sound speed meter positioned at a first sensing region along said pipe which provides a first effective sound speed signal, said first sensing region has a first cross-sectional compliance; a second sound speed meter configured to detect the acoustic pressure signals, the second sound speed meter positioned at a second sensing region along said pipe which provides a second effective sound speed signal, said second sensing region has a second cross-sectional compliance, wherein said first cross-sectional compliance is different than said second cross-sectional compliance to change the speed of sound propagating from the first sensing region to the second sensing region; and a signal processor, responsive to said first and said second sound speed signals, which provides a density signal indicative of said density of said fluid within said pipe; and a control device receiving said density signal and capable of controlling said process parameter to a predetermined level based on said density signal.