| 摘要 |
PURPOSE:To obtain a high efficiency particulate capturing nozzle by disposing a nozzle having small diameter on the surface of a filter capturing particulates and forming a gas introduction surface having a large diameter on the periphery of a nozzle hole at the forward end thereof. CONSTITUTION:A tape-like filter 2 made of silicon fibers, for example, is employed and a capturing nozzle 1 is disposed closely, at the forward end thereof, to the surface of the filter 2. The nozzle 1 is set with a small hole diameter and a flange-like gas introduction face 1b is formed, while spreading along the surface of the filter 2, around a nozzle hole 1a at the forward end thereof. Exhaust gas from a diesel engine is diluted through a dilution tunnel and fed, as a sample gas, to the nozzle 1 through an ejector. Since the nozzle diameter is decreased, the velocity of the exhaust gas striking the filter 2 is increased and the capturing efficiency is thereby enhanced. Furthermore, since the gas introduction face 1b spreads the exhaust gas on the filter 2, pressure on the surface of the filter is reduced thus enhancing the capturing efficiency.
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