Automatic pressure correction for level gauges in storage tanks

Patent metadata

Field	Value
Publication number	US-2017307461-A1
Application number	US-201615207693-A
Country	US
Kind code	A1
Filing date	Jul 12, 2016
Priority date	Apr 21, 2016
Publication date	Oct 26, 2017
Grant date	—

Abstract

A level gauge system for mounting on a roof of a semi-closed storage tank includes an automatic tank level gauge for determining a level reading for a liquid including at least one liquid component in the tank. A processor includes a memory storing pressure correction factors or a pressure correction factor equation for correcting the level reading for a measured gas pressure above the liquid in the tank. The processor is programmed for implementing choosing a selected pressure correction factor from the pressure correction factors or the equation based on a received current gas pressure above, and applying the selected pressure correction factor for automatically correcting the level reading provided by the tank level gauge to generate a corrected level reading which compensates for the current gas pressure above effects on the roof and on the level gauge.

First claim

1 . A method of pressure correction for level gauges, comprising:
measuring a current measured gas pressure above a liquid in a semi-closed tank including at least one liquid component therein having an automatic tank level gauge installed on a roof of said tank; choosing a selected pressure correction factor from a range of pressure correction factors or from a pressure correction factor equation based on said current gas pressure above, and applying said selected pressure correction factor for automatically correcting a level reading provided by said tank level gauge to generate a corrected level reading which compensates for said current gas pressure above effects on said roof and said tank level gauge.

2 . The method of claim 1 , wherein said semi-closed tank includes a breather valve.

3 . The method of claim 1 , wherein empirical data is used for generating said pressure correction factor equation.

4 . The method of claim 1 , wherein said pressure correction factors are stored in a lookup table, and wherein an interpolation mechanism is used for said choosing said selected pressure correction factor.

5 . The method of claim 1 , wherein said choosing and applying is performed by a processor included in said tank level gauge.

6 . The method of claim 1 , wherein said tank level gauge comprises a servo level tank gauge, or a radar level gauge.

7 . The method of claim 1 , further comprising using said corrected level reading for a custody transfer transaction, or for legal metrology where import duties are levied.

8 . A level gauge system for mounting on a roof of a semi-closed storage tank, comprising:
an automatic tank level gauge for determining a level reading for a liquid including at least one liquid component in said tank; a processor including a memory storing pressure correction factors or a pressure correction factor equation for correcting said level reading for a measured gas pressure above said liquid in said tank, said processor programmed for implementing:
choosing a selected pressure correction factor from said pressure correction factors or said equation based on a received current gas pressure above, and
applying said selected pressure correction factor for automatically correcting said level reading provided by said tank level gauge to generate a corrected level reading which compensates for said current gas pressure above effects on said roof and said tank level gauge.

9 . The level gauge system of claim 8 , wherein said pressure correction factors are stored in a lookup table, and wherein an interpolation mechanism is used for said choosing said selected pressure correction factor.

10 . The level gauge system of claim 8 , wherein said choosing and applying is performed by said tank level gauge.

Assignees

• Honeywell Int Inc

Inventors

• Van Bekkum Frank
• Althof Michiel
• Van Schie Ard

Classifications

• G01L27/005 Primary

  Apparatus for calibrating pressure sensors · CPC title

• G01F23/14

  by measurement of pressure · CPC title

• G01S7/40 Primary

  Means for monitoring or calibrating · CPC title

• G01F23/0023

  with a probe suspended by a wire or thread (with floats G01F23/40) · CPC title

• G01F25/20

  of apparatus for measuring liquid level · CPC title