BELL JAR CLEANING METHOD

摘要

The present invention provides a method for reliably eliminating contaminants and accretions at the inner surface of a reaction vessel (bell jar) used in producing polycrystalline silicon. The reaction vessel (bell jar) (1) used in producing polycrystalline silicon is placed on a receiving plate (2) with a rubber gasket (3) therebetween. The inside of the bell jar (1) in the state of being placed on the receiving plate (2) is provided with: a nozzle (4) for causing fine ice particles to impact the inside surface of the bell jar (1) while maintaining a set distance and angle; a hose (5) for sending fine ice particles and pure water to the nozzle (4); and a shaft (6) that has the ability to rotate for moving the position of the nozzle (4). The fine ice particles are produced by an icemaker (10). The fine ice particles favorably have a maximum diameter on the order of 0.3-3.0 mm. The fine ice particles are sent to the nozzle (4) by means of compressed air (8) having a pressure of 0.5 MPa-1 MPa, for example. The angle at which the fine ice particles are caused to impact the inside surface of the bell jar (1) from the nozzle (4) favorably is 30°-60°.