Valve calibration method and apparatus

A method of calibrating a Venturi valve, the Venturi valve having a variable shaft position, the Venturi valve operable to provide an air flow corresponding to the variable shaft position, the method comprising:

• a) installing the Venturi valve in a facility;
• b) after installing the Venturi valve, providing a plurality of voltages to an actuator, the actuator operable to change the variable shaft position dependent on said plurality of voltages,
• c) receiving from a source of flow measurements a flow measure for each variable shaft position corresponding to each of the plurality of voltages,
• d) storing information representative of the relationship between each of the plurality of voltages and the flow measures;
• and
• e) using the Venturi valve as a part of a system that regulates air flow within the facility.

A method of calibrating a Venturi valve, the Venturi valve having a variable shaft position, the Venturi valve operable to provide an air flow corresponding to the variable shaft position, the method comprising:

• a) determining a first actuator voltage associated with a first flow value;
• b) determining a second actuator voltage associated with a second flow value;
• c) providing a set of other voltages to the actuator and obtaining a corresponding flow measurement for each of the set of other voltages, the set of other voltages being between the first actuator voltage and the second actuator voltage;
• and
• d) storing information representative of the relationship between each of a plurality of voltages and the flow measures, the plurality of voltages including the first actuator voltage, the second actuator voltage and the set of other voltages.

An arrangement for calibrating a valve, the valve having a variable shaft position, the valve operable to provide a flow corresponding to the variable shaft position, the arrangement comprising:

• a source of flow measurements;
• and
• a processing circuit operable to
• provide a plurality of voltages to an actuator, the actuator operable to change the variable shaft position dependent on said plurality of voltages,
• receive from the source of flow measurements a flow measure for each variable shaft position corresponding to each of the plurality of voltages, and
• store information representative of the relationship between each of the plurality of voltages and the flow measures.