Gas exchange system flow configuration

摘要

Active compensation designs to offset the impact of gas diffusion sources and sinks in a photosynthesis and transpiration measurement system are disclosed. A sensor head for use in a gas exchange analysis system includes an active, piezoelectric flow splitting device for splitting a flow between a sample chamber and bypass pathway. The active flow splitting device is controlled by feedback from a downstream flow meter. A continuous measurement system for rapidly and accurately surveying large numbers of samples is described.

主权项

1. A gas exchange analysis sensor head apparatus comprising:
an active flow splitting device having a first output port and a second output port, the active flow splitting device configured to variably split an incoming gas flow between the first and second output ports; a sample chamber having an inlet and an outlet, the inlet coupled with the first output port of the active flow splitting device; a first gas analyzer coupled with the outlet of the sample chamber and configured to measure a concentration of a gas exiting the outlet of the sample chamber; a second gas analyzer coupled with the second output port of the active flow splitting device and configured to measure a concentration of said gas exiting the second output port of the active flow splitting device; a flow meter coupled between the first output port of the active flow splitting device and the inlet of the sample chamber the flow meter configured to measure a flow rate of gas entering the inlet of the sample chamber; and a feedback control circuit adapted to control the active flow splitting device to adjust the gas flow provided to the first output port responsive to a flow rate signal from the flow meter.