| 摘要 |
PURPOSE:To enable a gas flow rate to be reduced without dropping an inner pressure of a nozzle holder less than a specified pressure by a method wherein a shaft is rotated by a certain amount of degree and pushed into a device, an extremity end of the shaft closes a part of a gas passage of the nozzle holder, the shaft is rotated again and an opening of a communication passage communicating with a gas inlet port is gradually throttled. CONSTITUTION:Gas is flowed into a device at a gas inlet port 11, a flow rate of gas is adjusted at an opening (c) having a maximum area, and the gas is injected from three main nozzles 14. When a gas flow rate adjusting shaft 12 is rotated by 180 deg., a gas flow rate is adjusted at an opening (d) having a minimum area, and so a gas flow rate can be gradually adjusted, in a rotational angle 0 deg. to 180 deg.. As a gas flow rate adjusting shaft 12 is pushed into the device, a fixed rib 19 is abutted against a pushing plate 18 and fixed there. O-ring 15 partially closes a pass passage 13a to stop a supplying of gas into two main nozzles 14. If the gas flow rate adjusting shaft 12 is rotated by a degree of 360 deg., a gas flow rate is adjusted in an opening T of a minimum area in respect to one nozzle. Even in a range from 180 deg. to 360 deg., it is possible to make a gradual throttling of the gas flow rate.
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