Honeywell International Inc.

Zhanghua Wu

Guangli Xie

Kai Chen

Yaofu Gong

Bo Su Chen

Qidao Lin

Yuzhong June Wang

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.

Photoionization detector automated zero level calibration

Embodiments relate generally to systems and methods for shielding electrodes () within a photoionization detector (). A photoionization detector () may comprise an ultraviolet radiation source (); one or more detector electrodes (); one or more collection surfaces () extending vertically from the detector electrodes (); and a shielding material () located between the ultraviolet radiation source () and the one or more detector electrodes (), wherein the ultraviolet radiation () does not directly impinge on at least a portion of the one or more detector electrodes (). The one or more collection surfaces () may comprise a surface area that is not covered by the shielding material ().

Collection surface for electrodes in photoionization detector

A photoionization detector () comprises an ultraviolet radiation source (); one or more detector electrodes (and); and a shielding material () located between the ultraviolet radiation source () and the one or more detector electrodes (and), wherein the ultraviolet radiation () does not directly impinge on any part of the one or more detector electrodes (and). A method for gas detection comprises exposing a photoionization detector () to an environment containing a target gas; and shielding the one or more detector electrodes (and) from direct impingement from the ultraviolet radiation () via the shielding material ().

Shielding for electrodes in photoionization detector

A method of detecting gas with a photoionization detector (PID) system. The method includes powering on a photoionization detector, turning off an ultraviolet lamp of the photoionization detector by a controller of the PID system and keeping it turned off during the zero calibration procedure, flowing ambient air from a surrounding environment by a fan of the photoionization detector system past a detector electrode of the photoionization detector, processing an output of the detector electrode by the controller to determine a zero level of the photoionization detector, and storing the zero level in a memory of the photoionization detector system. The photoionization detector system in a detecting mode compares an output of the detector electrode to the zero level to determine if a threshold concentration of a gas is present.

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Shanghai, China

Zhanghua Wu