| 摘要 |
PURPOSE:To smoothly open a bell-jar top cap and prevent the failure of parts and the like by making the ascending speed of a lift slower before the cap opens at the time of opening the bell-jar top cap of a vacuum vessel. CONSTITUTION:In a vacuum vessel of vapor depositing apparatus, crystal growing apparatus, etc., the revolutions of a motor are slowed down to operate a lift 12 at a low speed at the beginning of disconnection of a bell-jar top cap 9 and a bell-jar base body 10, and when O-rings 8, 8' and the bell-jar base body disconnect, the number of revolutions of the motor is increased to operate the lift at a high speed. Then, the impact during opening of the bell-jar top cap is avoided, and the cap opens smoothly; therefore, the failure of quartz parts, carbon blocks, etc. is prevented. |
