초록 ▼

A photo-ionization detector (PID) including two detection units controls gas flows through the ionization chambers of the detection units for real-time self-cleaning and measurement. Operation of the PID can include flowing gas through the ionization chamber of one detection unit to measure the vola

A photo-ionization detector (PID) including two detection units controls gas flows through the ionization chambers of the detection units for real-time self-cleaning and measurement. Operation of the PID can include flowing gas through the ionization chamber of one detection unit to measure the volatile gas concentration while stopping gas flow through the ionization chamber of the other detection unit. A UV lamp converts oxygen contained in the closed ionization chamber to ozone, which removes contamination in the closed ionization chamber, Continuous gas flows can alternate between one ionization chamber to the other. Alternatively, a PID with only one gas detection unit intermittently interrupts the flow of the ambient gas in the ionization chamber.

대표청구항 ▼

A photo-ionization detector (PID) including two detection units controls gas flows through the ionization chambers of the detection units for real-time self-cleaning and measurement. Operation of the PID can include flowing gas through the ionization chamber of one detection unit to measure the vola

A photo-ionization detector (PID) including two detection units controls gas flows through the ionization chambers of the detection units for real-time self-cleaning and measurement. Operation of the PID can include flowing gas through the ionization chamber of one detection unit to measure the volatile gas concentration while stopping gas flow through the ionization chamber of the other detection unit. A UV lamp converts oxygen contained in the closed ionization chamber to ozone, which removes contamination in the closed ionization chamber, Continuous gas flows can alternate between one ionization chamber to the other. Alternatively, a PID with only one gas detection unit intermittently interrupts the flow of the ambient gas in the ionization chamber. in the controller is operable to remove from sampled signals artifacts caused by deviations from a perfectly circular rotation of the cylindrical drive roller surface. 18. A sheet feed system, comprising: a support arm having a first end and a second end and configured to turn about a pivot axis on a pivot located closer to the first end than the second end so that displacement of the first end causes a greater corresponding displacement of the second end; a roller mounted at the first end of the support arm and configured to rotate about a roller axis substantially parallel to the pivot axis; a sheet feed surface disposed adjacent to the roller and configured to receive a sheet between the sheet feed surface and the roller; a biasing member coupled to the support arm at a location between the pivot axis and the second end of the support arm and configured to use the roller against the sheet feed surface; an optical encoder having at least one component mounted at the second end of the support arm and configured to generate signals responsive to movement of the second end of the support arm; and