GB303012A - - Google Patents

Abstract

303,012. British Thomson-Houston Co., Ltd., (Assignees of Standerwick, R. G.). Dec. 24, 1927, [Convention date]. Regulating. - In a turbine-driven compressor set, the servo-motor for positioning the admission valve of the turbine is controlled by two pilot valves arranged in series, the pilot valves being positioned by separate governing means responsive to different operating conditions of the set. In the arrangement shown in the Figure, the set comprises a turbine 1 driving a centrifugal compressor 4, the admission valve 7 of the turbine being positioned by an oil-actuated servo-motor 15 acting through rack and cam gearing 17, 12, and lever 9. The valve 21, 22 of the servo-motor is actuated by a fluid motor 35 which is under the control of two pilot valves, the first, 57, of which is responsive to variations in the volume of fluid. passing through the compressor 4, the second, 38,. being controlled by a pre-emergency speed governor 48. Under normal conditions of working, the turbine is controlled solely by the volumeresponsive device, but should the speed become excessive, the speed governor 48 becomes effective and takes over control. The pilot valves 57, 38, and the servo-motor 15 with its valve 21, 22 are interconnected by links and levers as shown in order that the piston 35 may actuate the valve 21, 22 with the necessary follow-up motion. An. adjusting weight 79 and a dash-pot 78 are provided. The constant-volume governor comprises an inverted bell 74 to the opposite sides of which fluid is led by pipes 76, 77 from a flow nozzle 75 in the intake pipe 5 of the compressor. An oil pump 51 is mounted on the speed-governor shaft 49 and supplies the whole of the regulating system. It may also feed the lubricating system. Specification 289,026, [Class 110 (iii), Turbines &c.], is referred to.