Topas TDD590比較適合越來越多對熱氣體進行粒度分析的應用要求。對于此類測量，必須在不改變氣溶膠粒徑分布的情況下實現氣體冷卻。氣化材料的冷凝過程會極大地影響粒徑分布。

熱擴散干燥器用于在發生冷凝成液滴之前去除汽化的氣相。這種裝置將氣溶膠樣品加熱到與采樣點相同的溫度。加熱后的氣體流過充滿活性炭的吸附管。在吸附部分內，蒸發的材料通過擴散運輸過程在活性炭的表面被去除。初級氣溶膠在吸附管內不受影響，因為與吸附材料沒有直接接觸。 thermodenuder tdd 590 根據此原理工作。管尺寸、氣體加熱器和微控制器控制的溫度控制器專為高達 3 lpm 的氣體流速而設計。溫度可輕松調節至 400。

in increasing numbers of application particle size analysis in hot gases is requested. For such measurements a gas cooling must be realized without changing the particle size distribution of the aersol. particle size distribution can extremely affected by condesation processes of vaporised materials.

thermodenuders are used in order to remove the vaporised gas phase before ondensation to droplets occurs. such devices heat up the aerosol sample to the same temperature as at the point of sampling. the heated gas flows through an adsorption tube filled with active carbon. Inside the adsorption section vaporised materials are remobed at the surgace of activated carbon by means of diffusive transportation proesses. the primary aerosol is not affected inside the adsorption tube because there is no direct contact with the adsorptive material. the thermodenuder tdd 590 works according to this principle. The tube size ,gas heater and microporcessor controlled temperature controller are designed for gas flow rates up to 3 lpm. the temperature can be easil adjusted up to 400