Purge gas pressure monitoring system
AssigneeFluid Data Systems
InventorsEugene A. Glassey, Ralph A. Loh
Life of this patent
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Abstract
A purge gas pressure monitoring system has a piezometer tube running from a pressure measuring instrument into a medium to be monitored. A temperature detector device extends the length of the piezometer tube. Outputs from the pressure measuring instrument and the temperature detector device are coupled to a central processing device or microcomputer for monitoring the outputs and using the outputs along with stored data to calculate a corrected pressure signal which is corrected for errors including errors arising as a result of variations of the average temperature along the piezometer line from a reference value.
Claims9
A purge gas pressure monitoring system, comprising:
- a piezometer line having a first, outlet end for submerging in a medium to be monitored and a second end;
- a gas supply connected to the piezometer line for injecting gas into the medium in the form of bubbles from the outlet end of the piezometer line;
- a pressure-responsive instrument connected to the second end of the piezometer line for producing a first output signal proportional to the pressure at the second end of the piezometer line;
- a temperature detector device extending along the length of the piezometer line for producing a second output signal proportional to the average temperature along the piezometer line;
- data processing means connected to monitor said first and second output signals at periodic intervals for producing a corrected output signal after each interval in which said first output signal is corrected for variations in said second output signal from a reference temperature;
- said data processing means including memory means for storing program instructions and data;
- display means linked to said data processing means for displaying said corrected output signal to an operator;
- and
- input means linked to said data processing means for operator input of commands and data.
A method of measuring pressure in a body of liquid, comprising the steps of:
- sensing the pressure at a submerged level in the body of liquid to produce a first output pressure signal dependent on the sensed pressure;
- applying the pressure signal as an input to a pressure-responsive instrument at a location spaced from said submerged level, the pressure-responsive instrument having an output proportional to the pressure input;
- calculating an error compensation factor to compensate for predetermined errors in the output of the pressure-responsive instrument as a result of gas weights;
- modifying the output of said pressure-responsive instrument by said gas weights error compensation factor;
- sensing the average temperature between the submerged level and the pressure-responsive instrument;
- modifying the output of said pressure-responsive instrument as a function of the variation of said average temperature from a reference value;
- and
- providing a compensated output signal corrected for gas weights and temperature variations.
Dependencies are inferred from the claim text.