Mass flowmeter apparatus

• US 4,987,914 A
• Filed: 04/27/1990
• Issued: 01/29/1991
• Est. Priority Date: 01/11/1989
• Status: Expired due to Fees

• Current Assignee: Conoco Incorporated (ConocoPhillips)
• Original Assignee: Conoco Incorporated (ConocoPhillips)
• Inventors: Alworth, Charles W., Adney, Billy R., Jeffries, Bryce T., Durkee, John B.
• Primary Examiner(s): Cohan, Alan
• Application Number:
  US07/515,808
• Time in Patent Office: 277 Days
• Field of Search: 137/8, 137/14, 137/486, 137/487.5, 73/3, 73/200, 73/219, 73/220, 73/223
• US Class Current: 137/8
• CPC Class Codes: G01F 1/007 by measuring the level variations of storage tanks relative to the time
• CPC Class Codes: G01F 1/78 Direct mass flowmeters
• CPC Class Codes: G01F 23/14 by measurement of pressure
• CPC Class Codes: Y10T 137/0357 For producing uniform flow
• CPC Class Codes: Y10T 137/7759 Responsive to change in rate of fluid flow

Abstract

This invention relates to a method and apparatus for a liquid mass non-venting flowmeter. The flowmeter apparatus gives correct flow regardless of changes in density, viscosity, or composition of the liquid and corrects flow in spite of errors common in currently used flowmeters, such as calibration shifts, restricted orifices and/or bearing drag and blade wear of turbine meters. The non-venting characteristic allows use with toxic and corrosive materials.

Claims

1. A method for regulating mass flow of a liquid stream from a substantially vertical container having a known mass content per unit of height or weight and being in direct open communication with a source of liquid pressure, said method comprising the steps of:

providing a set minimum positive displacement pressure in the container;

filling the vertical container against the set pressure with minor disturbance of the set pressure;

monitoring the mass of a stream entering the container by measuring the change in pressure or weight within the container;

monitoring the amount of liquid in the vertical container over a measured time interval and determining the rate of flow as change in mass divided by elapsed time as liquid exits the container;

determining a correction factor as being the mass exiting the container divided by integrated output of previous flowmeter readings; and

adjusting the flow rate of exiting liquid to a target flow rate based upon the correction factor.

2. A method as described in claim 1 wherein the amount of liquid in the vertical container is monitored by measuring the height of liquid in the vertical container as differential pressure.

3. A method as described in claim 2 wherein the height of said column is transmitted to a computer means which determines a correction factor, which correction factor is utilized to actuate a valve actuator means to control liquid flow.