US 12,455,260 B2
Photo-ionization detector (PID) with multiple measuring cells and process using such a PID
Tim Blöcker, Lübeck (DE); and Lucas Pfennig, Lübeck (DE)
Assigned to DRÄGER SAFETY AG & CO. KGAA, Lübeck (DE)
Filed by Dräger Safety AG & Co. KGaA, Lübeck (DE)
Filed on Feb. 16, 2023, as Appl. No. 18/169,951.
Claims priority of application No. 10 2022 103 919.6 (DE), filed on Feb. 18, 2022; and application No. 10 2022 116 682.1 (DE), filed on Jul. 5, 2022.
Prior Publication US 2023/0266272 A1, Aug. 24, 2023
Int. Cl. G01N 27/66 (2006.01); G01N 27/64 (2006.01)
CPC G01N 27/66 (2013.01) [G01N 27/64 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A photo-ionization detector for detecting an ionizable substance in a gas, the photo-ionization detector comprising:
a measuring cell carrier;
a radiation source configured to emit ionizing electromagnetic radiation towards the measuring cell carrier; and
a plurality of measuring cells mounted on the measuring cell carrier, each of the plurality of measuring cells comprising a measuring electrode having a measurable electrical property that is at least temporarily changed or changeable by ionization of ionizable substance in the gas, each of the plurality of measuring cells being configured to generate a signal depending on the measurable electrical property, which generated signal correlates with a presence of ionizable substance in the gas,
wherein each of the plurality of measuring cells is associated with a respective state of the photo-ionization detector and the photo-ionization detector is selectively operable in each respective state,
wherein during operation of the photo-ionization detector in the state associated with one measuring cell of the plurality of measuring cells, a fluid connection is established between an environment of the photo-ionization detector and said one measuring cell of the plurality of measuring cells and at least a part of the emitted electromagnetic radiation reaches said one measuring cell of the plurality of measuring cells and at least one other measuring cell of the plurality of measuring cells is fluid-tightly separated from the environment.