Coriolis-type mass flowmeter

A Coriolis-type mass flowmeter, comprising

• a single rigid manifold block,
• two substantially identical conduit loops, each substantially encircling said block and each having its inlet and outlet ends solidly mounted to said block in juxtaposition with each other and with the ends of the other loop,
• said loops having parallel straight sections,
• drive means for oscillating said straight sections about their parallel perpendicular bisectors respectively, and
• means for measuring the magnitude of Coriolis forces, arising as a result of mass flow in each straight section while undergoing oscillatory motion.

A Coriolis-type mass flowmeter system, comprising

• two substantially identical conduit loops with juxtaposed ends,
• a series flow rigid manifold block having a flowmeter inlet, a flowmeter outlet and four juxtaposed ports for connection to the loop ends, said series block having internal channel means for communicating the flowmeter inlet with the inlet end of one of said loops, and communicating the outlet end of the one loop with the inlet end of the other loop and communicating the outlet end of the other loop with the flowmeter outlet for series flow through said loops,
• a parallel flow rigid manifold block having a flowmeter inlet, a flowmeter outlet and four juxtaposed ports for connection to the loop ends, said parallel block having internal channel means for communicating its flowmeter inlet with the inlet ends of both loops and communicating the outlet ends of both loops with the flowmeter outlet for parallel flow through said loops,
• means for oscillating corresponding sections of said loops, and
• means for measuring the magnitude of Coriolis forces arising as a result of mass flow in each section while undergoing oscillatory motion,
• said blocks being interchangeable to realize series or parallel flow in the loops of the flowmeter.

A Coriolis-type mass flowmeter, comprising

• a support,
• a continuous conduit loop substantially encircling said support having two juxtaposed ends solidly mounted to said support,
• drive means for oscillating a section of said loop about an axis midway between the ends of said section, and
• means for measuring the magnitude of Coriolis forces, arising as a result of mass flow in the section of conduit while undergoing oscillatory motion.

A Coriolis-type mass flowmeter, comprising

• a support,
• a conduit loop substantially encircling said support having a straight section and parallel inlet and outlet end sections perpendicular to the orthogonal projection of said straight section onto the plane defined by said inlet/outlet sections, the end sections being solidly mounted to said support,
• drive means for oscillating said straight section about an orthogonal axis passing through a point between the ends of said straight section, and
• means for measuring the magnitude of Coriolis forces arising as a result of mass flow in the straight section while undergoing oscillatory motion.

A Coriolis-type mass flowmeter, comprising

• single rigid manifold block having a coaxial inlet and outlet of the flowmeter,
• first and second conduit loops having parallel straight sections, the ends of each loop being parallel to each other and perpendicular to said straight section and solidly mounted to said block close to each other,
• channel means in said manifold block for communicating the inlet thereof with at least one of the inlet ends of said respective loops and for communicating the outlet of the manifold block with at least one of the outlet ends of the respective loops for series or parallel flow,
• a pair of drive means associated with each loop located approximately at the ends of the respective straight section for oscillating said straight section about its perpendicular bisector,
• sensor means juxtaposed with each pair of drive means for sensing the deflection of said straight section out of the nominal plane of said loop,
• control means responsive to the outputs of said position sensors on a given loop for controlling said drive means on the same loop, and
• means responsive to the output of the position sensors on both loops for measuring the combined magnitude of the Coriolis forces, arising as a result of mass flow in the straight sections of the conduit loops while undergoing oscillatory motion.

A signal processing and control method for a Coriolis-type mass flowmeter having at least one oscillating conduit, comprising

• oscillating a section of the conduit about an axis midway between the ends of said section,
• detecting the motions of the respective ends of said section and producing two complementary sensor outputs corresponding to said respective ends of said section, each sensor output including a drive component mixed with a Coriolis component,
• recovering the Coriolis component without the drive component from said two sensor outputs,
• recovering the drive component from said two sensor outputs and generating a reference signal for synchronous demodulation of the recovered Coriolis component, 90.degree. out-of-phase with the recovered drive component,
• controlling the oscillation of each conduit section with a drive signal derive from said recovered drive component by developing a drive signal corresponding to the first derivative of said recovered drive component, and
• synchronously demodulating a signal representing the recovered Coriolis component with a reference signal in quadrature with the drive component to produce an output signal indicative of mass flow.

A signal processing and control method for a Coriolis-type mass flowmeter having at least one oscillating conduit, comprising

• oscillating a section of the conduit about an axis midway between the ends of said section,
• detecting the motions of the respective ends of said section and producing two complementary sensor outputs corresponding to said respective ends of said section, each sensor output including a drive component mixed with a Coriolis component,
• recovering the drive component without the Coriolis component from said two sensor outputs,
• controlling the oscillation of each conduit in accordance with a drive signal derived from the recovered drive component, said drive signal corresponding to the first derivative of said recovered drive component.

In a Coriolis-type mass flowmeter having at least one oscillating conduit, the combination comprising

• an oscillation drive system coupled to the conduit to oscillate a section thereof about an axis midway between the ends of said section,
• a detector system arranged to sense the motions of the respective ends of said section producing complementary sensor outputs corresponding to said respective ends of said section, each including a drive component mixed with a Coriolis component,
• a signal processing circuit connected to receive said sensor outputs for recovering the Coriolis component therefrom without the drive component,
• a detection circuit connected to receive said recovered Coriolis component from said signal processing circuit and having an output signal indicative of mass flow, said detection circuit including a synchronous demodulator connected to receive the recovered Coriolis component and a reference signal in quadrature with the drive component and having an output signal indicative of mass flow.

In a Coriolis-type mass flowmeter having at least one oscillating conduit, the combination comprising

• an oscillation drive system coupled to the conduit to oscillate a section thereof about an axis midway between the ends of said section,
• a detector system arranged to sense the motions of the respective ends of said section producing complementary sensor outputs corresponding to said respective ends of said section, each including a drive component mixed with a Coriolis component,
• a signal processing circuit connected to receive said sensor outputs for recovering the drive component therefrom without the Coriolis component,
• a derivative circuit having an input connected to receive the drive component and an output forming a drive signal input to said oscillation drive system, said derivation circuit including a differentiator.

In a Coriolis-type mass flowmeter having at least one oscillating conduit, the combination comprising

• an oscillation drive system coupled to the conduit to oscillate a section thereof about an axis midway between the ends of said section,
• a detector system arranged to sense the motions of the respective ends of said section producing complementary sensor outputs corresponding to said respective ends of said section, each including a drive component mixed with a Coriolis component,
• a signal processing circuit connected to receive said sensor outputs for recovering the Coriolis component therefrom without the drive component and for recovering the drive component therefrom without the Coriolis component,
• a reference generator responsive to the recovered drive component having at least one output forming a reference signal with a predetermined phase relationship thereto, and
• at least one synchronous demodulator having a signal input connected to receive the recovered Coriolis component and a reference input connect to receive said reference signal and an output indicative of a detected parameter.

A signal processing and control method for a Coriolis-type mass flowmeter having at least one oscillating conduit, comprising

• oscillating a first conduit section about an axis midway between the ends of said first section,
• oscillating a second conduit section about an axis midway between the ends of said second section in synchronism with said first section,
• detecting the motions of the respective ends of said first section and producing two complementary sensor outputs corresponding to said respective ends of said first section, detecting the motions of the respective ends of said second section and producing two other complementary sensor outputs corresponding to said respective ends of said second section, each sensor output including a drive component mixed with a Coriolis component,
• recovering the Coriolis component without the drive component from both pairs of sensor outputs,
• recovering the drive component from said sensor outputs and generating a reference signal for synchronous demodulation of the recovered Coriolis component, 90.degree. out-of-phase with the recovered drive component,
• controlling the oscillation of each conduit section with a drive signal derived from said recovered drive component by developing a drive signal corresponding to the first derivative of said recovered drive component, and
• synchronously demodulating a signal representing the recovered Coriolis component with a reference signal in quadrature with the drive component to produce an output signal indicative of mass flow.

A signal processing and control method for a Coriolis-type mass flowmeter having at least one oscillating conduit, comprising

• oscillating first conduit section about an axis midway between the ends of said section,
• oscillating second conduit section about an axis midway between the ends of said second section in synchronism with said first section,
• detecting the motions of the respective ends of said first section and producing two complementary sensor outputs corresponding to said respective ends of said first section, detecting the motions of the respective ends of said second section and producing two other complementary sensor outputs corresponding to said respective ends of said second section, each sensor output including a drive component mixed with a Coriolis component,
• recovering the drive component without the Coriolis component from both pairs of sensor outputs,
• controlling the oscillation of each conduit in accordance with a drive signal derived from the recovered drive component, said drive signal corresponding to the first derivative of said recovered drive component.

In a Coriolis-type mass flowmeter having at least one oscillating conduit, the combination comprising

• another conduit,
• an oscillation drive system coupled to the conduit to oscillate a section thereof about an axis midway between the ends of said section, said oscillation drive system also being coupled to said other conduit to oscillate a section thereof about an axis midway between the ends of said section in synchronism with the section of said one conduit,
• a detector system arranged to sense the motions of the respective ends of said section of said one conduit producing complementary sensor outputs corresponding to said respective ends of said section of said one conduit, said detector system further arranged to sense the motions of the respective ends of said section of said other conduit producing complementary sensor outputs corresponding to said respective ends of said section of said other conduit, including a drive component mixed with a Coriolis component,
• a signal processing circuit connected to receive said sensor outputs for recovering the Coriolis component therefrom without the drive component, and
• a detection circuit connected to receive said recovered Coriolis component from said signal processing circuit and having an output signal indicative of mass flow, said detection circuit including a synchronous demodulator connected to receive the recovered Coriolis component and a reference signal in quadrature with the drive component and having an output signal indicative of mass flow.

In a Coriolis-type mass flowmeter having at least one oscillatory conduit, the combination comprising

• another conduit,
• an oscillation drive system coupled to the conduit to oscillate a section thereof about an axis midway between the ends of said section, said oscillation drive system also being coupled to said other conduit to oscillate a section thereof about an axis midway between the ends of said section in synchronism with the section of said one conduit,
• a detector system arranged to sense the motions of the respective ends of said section of said one conduit producing complementary sensor outputs corresponding to said respective ends of said section of said one conduit, said detector system further arranged to sense the motions of the respective ends of said section of said other conduit producing complementary sensor outputs corresponding to said respective ends of said section of said other conduit, including a drive component mixed with a Coriolis component,
• a signal processing circuit connected to receive said sensor outputs for recovering the drive component therefrom without the Coriolis component, and
• a derivation circuit having an input connected to receive the drive component and an output forming a drive signal input to said oscillation drive system, said derivation circuit including a differentiator.

In a Coriolis-type mass flowmeter having at least one oscillating conduit, the combination comprising

• another conduit,
• an oscillation drive system coupled to the conduit to oscillate a section thereof about an axis midway between the ends of said section, said oscillation drive system also being coupled to said other conduit to oscillate a section thereof about an axis midway between the ends of said section in synchronism with the section of said one conduit,
• a detector system arranged to sense the motions of the respective ends of said section of said one conduit producing complementary sensor outputs corresponding to said respective ends of said section of said one conduit, said detector system further arranged to sense the motions of the respective ends of said section of said other conduit producing complementary sensor outputs corresponding to said respective ends of said section of said other circuit, including a drive component mixed with a Coriolis component,
• a reference generator responsive to the recovered drive component having at least one output forming a reference signal with a predetermined phase relationship thereto, and
• at least one synchronous demodulator having a signal input connected to receive the recovered Coriolis component and a reference input connect to receive said reference signal and an output indicative of a detected parameter.