Photoionization detector automated zero level calibration
AssigneeHoneywell International Inc.
InventorsGuangli Xie, Bo Chen, Zhanghua Wu, Yaofu Gong
Life of this patent
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Abstract
A method of detecting gas includes determining and storing, by a controller, a zero level of a photoionization detector using ambient air inflow when an ultraviolet lamp is in a turned OFF state, wherein the stored zero level is based on an ambient temperature; sampling, by the controller, an output of a detector electrode of the photoionization detector when the ultraviolet lamp is in a turned ON state; and comparing the sampled output of the detector electrode to the stored zero level to determine if a threshold concentration of a gas is present.
Claims17
A method of detecting gas with a photoionization detector system, comprising:
- determining and storing, by a controller, a zero level of a photoionization detector using ambient air inflow, wherein the stored zero level is based on an ambient temperature;
- sensing the ambient temperature;
- adapting the stored zero level algorithmically based on a change sensed in the ambient temperature;
- sampling, by the controller, an output of a detector electrode of the photoionization detector when an ultraviolet lamp is in a turned ON state;
- and
- comparing the sampled output of the detector electrode to the stored zero level to determine if a threshold concentration of a gas is present.
A photoionization detector system, comprising:
- a controller that is communicatively coupled to an output signal of a detector electrode;
- a zero calibration application, executed by the controller, configured to:
- turn off an ultraviolet lamp of the photoionization detector system during a zero calibration procedure wherein the zero calibration application is stored in a memory of the photoionization detector system, process the output signal of the detector electrode to determine a zero level of the photoionization detector system,
- store the zero level in the photoionization detector system, wherein the stored zero level is based on an ambient temperature, and
- sample and compare the sampled output signal with the stored zero level to determine if a threshold concentration of a gas is present.
Dependencies are inferred from the claim text.