Adsorption Pump
Adsorption Pump
a vacuum pump the action of which is based on the physics of adsorption of evacuated gas on the surface of the adsorbent. Zeolites serve most frequently as adsorbents, and silica gels and active carbon do more rarely. The adsorbent is cooled with liquid nitrogen in order to increase adsorption. In time the adsorbent becomes saturated with gas and the action of the adsorption pump gradually decreases, but it is restored after it is heated to 100°-150°C and evacuated with a rough exhaust. The absolute pressure obtained is up to 10 micronewtons per sq m (1.10-7 mm of mercury).