Coating smooth metal e.g. inside wall of cryo-pump with porous adsorbent - by spraying granules of e.g. activated charcoal onto wet liq. cement adhesive, after cleaning metal surface

摘要

Prodn. of an adsorbent layer of porous granulate (I), which can be regenerated or reactivated and is stable from ca. 4 K to 300 deg. C, on a smooth metallic surface, e.g. an activated charcoal granulate coating on the inside wall of a cryo-pump, involves (a) prepg. the metal surface, e.g. cleaning and/or degreasing; (b) spraying with a uniform coating of liquid, sprayable ceramic adhesive (II) of predetermined thickness; (c) immediately applying (I) to the wet (II) coating by pneumatic spraying in stips in one pass over the entire surface, without removing excess material between the strips; (d) removing excess (I), not firmly held by the (II); and (e) hardening and/or curing the resultant coating. Heat-resistant (II) is pref. used. (II) is applied with a paint spray gun, pref. with an enlarged nozzle with a dia. of ca. 2-3 mm; and (I) with a sand blasting gun, pref. with a nozzle ca. 2-5 times larger than usual for abrasive equipment. USE/ADVANTAGE - (I) is completely effective on the vacuum side, since its pores are not blocked by (II). The coating has good adhesion on cooling to low temp. many times. Even non-horizontal surfaces can be coated very easily and very quickly using automatic machinery.