the aggregate of standard auxiliary devices of a vacuum system. Vacuum accessories require extremely tight fitting of all parts and connections, with very little gas emission through walls and seals. Vacuum accessories include the following items: manually, electrically, hydraulically, or pneumatically operated shutoff and control valves; similarly operated gates for closing large-diameter openings; valve- and needle-type collecting devices for the precise monitoring of extremely minute quantities of gas, or tubular collecting devices that open a channel for the gas upon heating of a capillary tube; electric-power inputs for cooling water or condensed gases; inspection holes for the observation of processes in a vacuum and for the removal of various types of emissions; and several types of devices for the transmission of mechanical movement into the vacuum spaces. Mechanical vacuum gauges (other types of vacuum gauges, in view of their variety and complexity, constitute an independent branch of vacuum technology— vacuum measurement) are also included among vacuum accessories.
The joints in vacuum accessories in a low-vacuum system are sealed by gaskets made of vacuum rubber; movable rods are sealed with specially designed packing devices. Bellows, which separate the drive mechanism from the vacuum space, are usually used for movable rods in high and ultrahigh-vacuum systems. Vacuum fitting gaskets and packings for ultrahigh-vacuum systems are made of special types of heat-resistant rubber, various kinds of plastics, or plastic metals.
REFERENCESLanis, V. A., and L. E. Levina. Tekhnika vakuumnykh ispytanii, 2nd ed. Moscow-Leningrad, 1963.
Pipko, A. I., V. Ia. Pliskovskii, and E. A. Penchko. Oborudovanie dlia otkachki vakuumnykh priborov. Moscow-Leningrad, 1965.
A. V. BALITSKII