Mass flow meter systems and methods

• US 6,564,825 B2
• Filed: 08/23/2002
• Issued: 05/20/2003
• Est. Priority Date: 04/13/2001
• Status: Expired due to Fees

• Current Assignee: Flowmatrix Incorporated
• Original Assignee: Flowmatrix Incorporated
• Inventors: Laragione, Robert, Lowery, Patrick A., Thordarson, Petur
• Primary Examiner(s): Buiz, Michael Powell
• Assistant Examiner(s): Krishnamurthy, Ramesh
• Application Number:
  US10/226,378
• Publication Number:
  US 20020195145A1
• Time in Patent Office: 270 Days
• Field of Search: 137/486, 137/487.5, 738/61, 738/614.2, 738/615.2, 738/615.3, 738/616.1, 738/616.2, 700/282, 251/118, 251/120, 251/121
• US Class Current: 137/487.5
• CPC Class Codes: G05D 7/0635 by action on throttling means G05D7/0688, G05D7/0694 take precedence
• CPC Class Codes: Y10T 137/0318 Processes
• CPC Class Codes: Y10T 137/0989 Acceleration responsive valve control
• CPC Class Codes: Y10T 137/7761 Electrically actuated valve

Abstract

A flow meter system that calculates mass flow rate based only on a single pressure signal. A flow controller is arranged in parallel with a restriction such that it constant pressure differential is maintained across the restriction. The pressure, and temperature if not controlled, of the fluid flowing through the restriction is measured on either side of the restriction. The pressure is compared to a plot of pressure versus mass flow rate calculated for the specific restriction and fluid being measured. The constant pressure differential maintained across the restriction yields a linear relationship between pressure and flow rate. If temperature is not controlled, the plot or pressure versus mass flow rate will remain linear, but the slope of the curve will be adjusted based on the temperature of the fluid.

Claims

1. A mass flow control system comprising:

a flow controller capable of controlling a flow rate through the mass flow control system;

said controller connected in series with a mass flow meter and generating a voltage signal to a meter circuit;

said mass flow meter comprising an inlet with a diameter and an outlet with a diameter;

a flow restrictor having a restriction chamber and a pressure balancing system interposed between the inlet and outlet;

the restriction chamber having a cylindrical restriction wall with a diameter less than the diameters of the inlet and outlet; and

, a temperature sensor upstream from the flow restrictor providing input to the meter circuit;

said meter circuit having calibration data whereby the meter circuit generates a flow output signal based on the calibration data, the input from the temperature sensor and the voltage signal;

said miss flow meter is connected to a valve control feedback loop system;

whereby the mass flow meter sends the flow output signal to the valve control feedback loop system and said feedback system compares the flow output signal with a predetermined flow rate to generate a flow control signal;

said valve control feedback loop system is connected to the flow controller;

whereby said feedback system sends the flow control signal to the flow controller to operate the flow controller to change the flow rate.

2. The mass control system of claim 1 where the flow controller comprises a piezoelectric actuator control and a valve.

3. The mass control system of claim 1 where the flow controller comprises a solenoid actuator control and a valve.

4. The mass control system of claim 1 where the flow controller generates a current signal which is converted to the voltage signal.