The present utility model relates to a device for improving gas detection in a photoionization detector. A gas detector is provided. The device reduces interference of photoelectric noise on the reading of the gas detector for target gases such as volatile organic compounds.

The present utility model relates to a device for improving gas detection in a photoionization detector. A gas detector is provided. The device reduces interference of photoelectric noise on the reading of the gas detector for target gases such as volatile organic compounds.

A sensor is provided for detecting small concentrations of volatile organic compounds in ambient air. The sensor has a lamp assembly and a gas sampling chamber assembly which are operatively associated. The gas sampling chamber assembly has an ionization chamber and an electrode assembly. The electrode assembly has sensing, counter and auxiliary electrodes and circuitry. The electrodes are positioned within the ionization chamber and are separated from one another. The circuitry is configured to apply a voltage difference to the sensing and counter electrodes, control an electrical potential of the auxiliary electrode to be substantially equal to an electrical potential of the counter electrode, measure/estimate a current at the sensing electrode and at the auxiliary electrode, determine a difference between the current at the sensing electrode and the current at the auxiliary electrode, and correct the current at the sensing electrode by using the difference.

A sensor is provided for detecting small concentrations of volatile organic compounds in ambient air. The sensor has a lamp assembly and a gas sampling chamber assembly which are operatively associated. The gas sampling chamber assembly has an ionization chamber and an electrode assembly. The electrode assembly has sensing, counter and auxiliary electrodes and circuitry. The electrodes are positioned within the ionization chamber and are separated from one another. The circuitry is configured to apply a voltage difference to the sensing and counter electrodes, control an electrical potential of the auxiliary electrode to be substantially equal to an electrical potential of the counter electrode, measure/estimate a current at the sensing electrode and at the auxiliary electrode, determine a difference between the current at the sensing electrode and the current at the auxiliary electrode, and correct the current at the sensing electrode by using the difference.

An optogalvanic effect (OGE) detection system utilizes an intracavity sample cell and a circuit that provides low noise stable excitation and maintenance of a radio frequency (rf) driven gas discharge within the sample cell and a direct current output proportional to the if driving voltage, associated monitoring devices and software. When an optical stimulus interacts with the discharge, any electrical change in the discharge can be simply determined with high precision and accuracy by measuring the impedance of the discharge via a measurement of the direct current output. In a preferred embodiment the rf gas discharge is created with a series resonant oscillator with two push pull sections connected together to generate the high voltage signal. A current source provides a low noise stable current to power the oscillator sections. A band pass amplifier filters the current of the discharge prior to measuring it.

An optogalvanic effect (OGE) detection system utilizes an intracavity sample cell and a circuit that provides low noise stable excitation and maintenance of a radio frequency (rf) driven gas discharge within the sample cell and a direct current output proportional to the if driving voltage, associated monitoring devices and software. When an optical stimulus interacts with the discharge, any electrical change in the discharge can be simply determined with high precision and accuracy by measuring the impedance of the discharge via a measurement of the direct current output. In a preferred embodiment the rf gas discharge is created with a series resonant oscillator with two push pull sections connected together to generate the high voltage signal. A current source provides a low noise stable current to power the oscillator sections. A band pass amplifier filters the current of the discharge prior to measuring it.

The present utility model relates to a device for improving gas detection in a photoionization detector. A gas detector is provided. The device reduces interference of photoelectric noise on the reading of the gas detector for target gases such as volatile organic compounds.

The present utility model relates to a device for improving gas detection in a photoionization detector. A gas detector is provided. The device reduces interference of photoelectric noise on the reading of the gas detector for target gases such as volatile organic compounds.

Methods and systems for detecting and limiting the water in a photoionization detector are provided. The method may include powering off a lamp configured to ionize particles of air. The method may also include monitoring a signal from the photoionization detector. The signal may be monitored based on a current between a signal electrode and a bias electrode. In an instance the signal is above a signal threshold, the method may also include electrolyzing one or more particles of water present in the photoionization detector by closing a leakage switch in order to allow current to flow through the bias electrode and the signal electrode. In an instance the signal is below the signal threshold, the method may include powering on the lamp to begin photoionization detection. Corresponding systems are also provided.

Methods and systems for detecting and limiting the water in a photoionization detector are provided. The method may include powering off a lamp configured to ionize particles of air. The method may also include monitoring a signal from the photoionization detector. The signal may be monitored based on a current between a signal electrode and a bias electrode. In an instance the signal is above a signal threshold, the method may also include electrolyzing one or more particles of water present in the photoionization detector by closing a leakage switch in order to allow current to flow through the bias electrode and the signal electrode. In an instance the signal is below the signal threshold, the method may include powering on the lamp to begin photoionization detection. Corresponding systems are also provided.