GB191110940A - Improvements in or relating to the Control of Elastic Fluid Compressing Plants. - Google Patents

Abstract

10,940. Kubler, G., Woollatt, G. S., and Fraser & Chalmers. May 5. Plant; regulating.-In plants for compressing elastic fluids, of the type in which a piston-compressor set is fed by a turbo-compressor set driven by a turbine utilizing the exhaust steam from the engine driving the piston compressor, the speed and output of the turbo-compressor is proportional to the speed and output of the piston compressor; when these are small, a pulsatory current is set up in the delivery pipe of the turbo-compressor, and it may be wasteful to run the turbo-compressor. The pulsatory current has hitherto been overcome by opening by hand a blow-off valve on the delivery of the turbo-compressor. According to the invention, at predetermined speeds or pressures of the piston compressor, the blow-off valve is opened automatically and the turbine driving the turbocompressor is shut down, both functions being performed in some cases by the same operating- mechanism. Fig. 1 shows the turbo-compressor portion of a plant in which exhaust steam is supplied to a turbine 1 from a pipe 4, by way of a non-return valve 6, steam receiver 6<a>, pipe 7, and normally open valve 8, and exhausts into a condenser through a pipe 9. The delivery pressure of the piston compressor (not shown) has access by a pipe 16 to a pressure governor 12 connected to a rod 13<a> attached as usual to the steam cut-off gear of the engine driving the piston compressor, but also connected by a floating lever 17 and rod 18 with the blow-off valve 3 of the turbo-compressor. The pipe 16 also communicates with the distributing-valve 19 of a piston 21, which controls the movement of the blow-off valve and is also adapted, through the medium of a sleeve 25 on the piston-rod, to control the passage of compressed fluid through a pipe 28 for opening a valve 10 which puts the steam-pipe 4 in direct communication with the condenser. Between predetermined points A and B, the movement of the end of the floating lever effects a proportionate opening movement of the blow-off valve. When the point B is reached, the control piston 21 is moved from top to bottom, and the valve is fully opened. Communication now being established between the passages 26, 27, the valve 10 is opened, the valves 6, 8 close automatically, steam exhausts directly into the condenser, and the turbine is shut down with the steam receiver 6<a> full. The blow-off valve may be held in the closed position by hand-operated mechanism 62, 63. The pressure from the pipe 16 may be transmitted through a liquid. Modifications are described in which (1) the floating lever is operated by a combined speed and pressure governor of the well-known Whitmore type; any form of speed, pressure, or speed and pressure governor, however being suitable; (2) the blow-off valve takes the form of a piston valve and the governor actuates the control piston directly, the distributing-valve 19 being dispensed with; (3) the turbine valves 8, 10 are mounted on a common rod in the same chamber so that one closes as the other opens.