Method for cleaning bell jar, method for producing polycrystalline silicon, and apparatus for drying bell jar

Abstract

A bell jar includes a metallic bell jar ( 1 ), and a metallic base plate ( 2 ) on which the bell jar ( 1 ) is placed, and packing ( 3 ) seals an inside of a container. To the base plate ( 2 ), a pressure gauge ( 4 ), a gas introduction line ( 5 ), and a gas discharge line ( 6 ) are connected so as to allow monitoring of internal pressure of the bell jar ( 1 ) and introduction and discharge of a gas. A vacuum pump ( 7 ) is provided in a path of the gas discharge line ( 6 ), and the vacuum pump ( 7 ) reduces internal pressure of the bell jar so as to be lower than vapor pressure of water. The vacuum pump ( 7 ) reduces the internal pressure of the bell jar so as to be lower than vapor pressure of water, thereby efficiently removing moisture, and completing drying of the bell jar in a short time.

1 - 8 . (canceled) 
     
     
         9 . An apparatus for drying a bell jar used for producing polycrystalline silicon by the Siemens method,
 wherein the apparatus can form an airtight space by providing the bell jar, and includes a vacuum line for reducing air pressure in the airtight space, and a dry air line for returning the air pressure in the airtight space to normal pressure.