In an air ionizing apparatus of a type utilizing a sheath gas not containing water (hydrogen) or impurities to sheathe corona electrodes, sufficient amount of ions are generated to fully eliminate static electricity from the interior of a production environment such as a clean room and to prevent the impurities from depositing on the corona electrodes. The tips of corona electrodes 21a and 21b are positioned inwardly of the tips of sheath gas nozzles 4a and 4b, respectively, by a certain distance. The distance is so determined that for a sheath gas containing no negative gaseous molecules, electrons emitted by corona discharge can reach air existing outside the sheath gas nozzle 4b and that for a sheath gas containing the negative gaseous molecules, negative ions emitted by corona discharge can rapidly disperse into the air outside the sheath gas nozzle 4b without remaining in the interior of the nozzle 4b.
An apparatus for detecting the minor constituents of a sample with high efficiency in positive and negative ion monitoring modes. The directions in which the sample gas is forced to flow in the ionized region within the ion source are properly switched in the positive and negative ion monitoring modes, respectively, thereby enabling both positive ions and negative ions to be detected with high sensitivity.
An ionizer of a corona discharge type is configured to increase the yield of ions while minimizing contamination of a discharge electrode by foreign matters. In the ionizer, a gas path unit (11) supplied with clean gas has internal clean gas paths (50, 48) in an electrode assembly (40), and clean gas is released through each internal clean gas path (50, 48) to make a clean gas flow enclosing a front end portion of a discharge electrode (12). The electrode assembly (40) has a guard ring (46) encircling the discharge electrode (12), and the guard ring (46) has external air inlet openings (46b) permitting free passage of atmospheric air. The clean gas flow enclosing the tip of the discharge electrode (12) inhales atmospheric air through external air inlet openings (46b) of the guard ring (46) and changes to ionized air.
An ionizer creates a corona current distribution having a balanced flow of positive and negative ions in a variable ion mobility gaseous environment. The balanced flow of positive and negative ions are directed toward a workspace or target located in the gaseous environment and downstream from the ionizer. The ionizer includes a corona electrode, a counterelectrode, a corona-free dc bias electrode, and a control circuit. The corona electrode has a negative polarity. The counterelectrode has an ion collecting surface. The corona-free dc bias electrode has a positive polarity. The control circuit controls the output of the corona-free electrode so as to cause a balanced flow of positive and negative ions to be emitted from the ionizer and directed towards the workspace or target. In this manner, a static-free environment is created at the workspace or target.
An ionizer that creates a corona current distribution having a balanced flow of positive and negative ions in a variable ion mobility gaseous environment, such as an environment of substantially nitrogen. The balanced flow of positive and negative ions is directed toward a workspace or target located in the gaseous environment downstream from the ionizer. The ionizer includes a counterelectrode, a positive ion emitter, a negative ion emitter, and a control circuit. The counterelectrode has at least two spatially isolated collecting surfaces. The positive and negative ion emitters are spatially isolated from each other so that the outputs of each of the emitters do not reach the other emitter.
Static neutralization of a charged object is provided by generating, in an ionizing cell or module, an ion cloud having a mix of positively and negatively charged ions, and reshaping the ion cloud by redistributing the ions into two regions of opposite polarity by using a second voltage. The second voltage creates an electrical field, which is preferably located in the vicinity of the ion cloud. The redistribution of the ions increases the effective range in which available ions may be displaced or directed towards the charged object. The electrical field redistributes ions that form the ion cloud. Ion redistribution within the ion cloud occurs because ions having a polarity corresponding to the polarity of the second voltage are repelled from the electrical field, and ions having a polarity opposite from that of the electrical field are attracted to electrical field. Redistribution of the ions into two regions of opposite polarity in the ion cloud in turn reshapes the ion cloud so that a portion of the cloud corresponding to the repelled ions is displaced by ions attracted to the electrical field, thus enhancing the range in which the ions may be dispersed or directed. This manner of redistributing ions into two regions is sometimes referred to as "ion polarization" in the disclosure herein.
