GB930381A - Improvements in or relating to regulating arrangements for steam power plants including a steam boiler having low storage capacity - Google Patents

Abstract

930,381. Steam power plant; turbines. SIEMENS - SCHUCKERTWERKE A.G. April 11, 1960 [April 11, 1959], No. 12920/60. Addition to 856,323. Classes 110 (3) and 122 (3). In a control system for a steam power plant comprising a turbine 1, 3, a boiler 7 with low storage capacity and a working medium storage means, e.g. a cold condensate accumulator 10, and in which the supply and discharge of the working medium to and from the storage means 10 is regulated in accordance with turbine load by first and second pumps connected in series by a conduit; the first pump 30 pumping water from the condenser 17 and the second 22 being capable of pumping water from the storage means via a pipe 54 connecting the storage means to a point in the conduit between the two pumps, the throughflow of the second pump, which throughflow controls the supply and discharge of water to and from the accumulator, is regulated in dependence on the ratio of the quantities of water passing through the first and second pumps respectively. The pump 30 discharges through a valve 29 operated in accordance with the water level in the condenser 17 by a controller 32. The throughflows of the pumps 30 and 22 respectively are measured by flow devices 37 and 38 which transmit signals through lines 39 and 40 respectively to a comparison controller 36 which controls through line 41 the motor 42 driving the pump 22. The turbine inlet valve 4 is influenced by a controller 5 influenced by turbine load and by signals such as e.g. n and e dependent on speed and electrical characteristics respectively. Variations in turbine load are signalled via a line 55 to a controller 34 which in turn transmits a signal by line 56 to the controller 36. During normal operation the quantities flowing through both pumps 22 and 30 are equal and no condensate is supplied to or taken from the accumulator 10. If, however, due to turbine load alteration a signal is sent to controller 36 the output of pump 22 is changed accordingly. After the necessary regulation has been effected the controller 34 is reset by a signal 43 from the controller 36 which is reset by a feed-back signal 44 to restore the water level in the accumulator 10 to its normal value. In a modification, Fig. 2 (not shown), the controller 36 acts on a valve on the delivery side of the pump 22 and the signal 44 is dependent on the difference in water level in the accumulator and in the feed-water container. In a further modification, Fig. 3 (not shown), the storage means is of the displacement type and the controller 36 is reset by a device influenced by temperature fluctuations in the storage means.