Mechanism of Steam Engines Part 7

Tham khảo tài liệu 'mechanism of steam engines part 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 74 MECHANISM OF STEAM ENGINES Fig. 84. Fig. 85. GOVERNING DEVICES FOR SINGLE-VALVE ENGINES 75 decrease the lead increases for a time then decreases so that the valve does not open the port at all when the eccentric is i8o with the crank. This diagram is for the governor shown in Fig. 87. Another fact to be noticed here is that no eccentric is used the eccentric being replaced by a pin attached to the governor arm. The pin E of course revolves about the center of the shaft when the wheel turns and drives the eccentric rod in the same way as would an eccentric whose center was at E. This is an advantage on a high-speed engine since an eccentric running at high speed is liable to cause trouble. The position of the short heavy arm which carries the pin E is controlled by the outer weight arm through the short link. As the speed increases the outer arm swings relative to the flywheel and in turn swings the eccentric arm about p thus changing the position of E relative to the center of the shaft and crank. . 60. Inertia Governors. No governors which depend solely upon centrifugal force for their operation can be very sensitive because ỉn order to cause the weights to move out the speed must increase an 76 MECHANISM OF STEAM ENGINES Fig. 87. Governor for American-Dall Engine. Fig. 88. Governor for Ridgway .