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US 6,266,964 B1Granted
Use of electronic expansion valve to maintain minimum oil flow
AssigneeAmerican Standard International Inc.
InventorsJonathan M. Meyer, Lee L. Sibik, Sean A. Smith
Life of this patent
Estimating the term…
Abstract
A method of controlling an expansion valve including the steps of: measuring a primary system condition; determining an error in the primary system condition; measuring a secondary system condition; determining an error in the secondary system condition; and modulating the expansion valve based upon the larger of the first or second error.
Claims13
A method of controlling liquid level in an HVAC system comprising the steps of:
- physically calibrating a liquid level sensor to a desired level;
- calculating an offset from a selected point of the liquid level sensor to a lower end;
- measuring a liquid level;
- subtracting the calculated offset from the measured liquid level;
- comparing the subtracted result to zero to determine an error;
- and
- controlling the liquid level to minimize the error.
4 more elements
A method of controlling the liquid level in an HVAC system comprising the steps of:
- physically calibrating a liquid level sensor to a desired level;
- selecting any point in the sensor's range;
- using that selected point as a setpoint;
- and
- controlling the liquid level in the HVAC system to the setpoint.
2 more elements
Apparatus controlling the liquid level in an HVAC system comprising:
- a liquid level sensor for measuring a liquid level;
- a liquid level modulator for modulating the liquid level;
- a device physically calibrating the liquid level sensor to a desired level;
- and
- a controller calculating an offset from a selected point of the liquid level sensor to a lower end, subtracting the calculated offset from the measured liquid level, comparing the subtracted result to zero to determine an error, and controlling the liquid level modulator to minimize the error.
2 more elements
Dependencies are inferred from the claim text.