| 摘要 |
PURPOSE:To respectively maintain a throttle part at a low temperature further a spray pin part at a high temperature so as to suppress the adhesion of carbon, by providing a heat insulating part between the throttle part and the spray pin part which are provided in the end of a needle valve fitted to the jet of a nozzle. CONSTITUTION:A needle valve 3 has in the end side of its tapered seated surface 4 a column-shaped throttle part 5 and a tapered spray pin part 6, and the throttle part 5 is fitted to a jet 2 in a nozzle body 1 through a fine clearance. Here the spray pin part 6 is successively connected in a line with a point end of the throttle part 5 through a tapered surface 7, further this successively connected part provides a peripheral groove 8 to be recessed over the whole periphery as a heat insulating part. And the existence of a space by the peripheral groove 8 suppresses transmission of heat from the spray pin part 6 to the throttle part 5. In this way, the needle valve 3 maintains the throttle part 5 at a low temperature suppressing the adhesion of carbon while the spray pin part 6 at a high temperature promptly destroying the adhering carbon by fire. |
