| 摘要 |
1,148,345. Fluid-pressure servomotor systems. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. Feb. 21, 1967 [ Feb. 23, 1966], No.8121/67. Heading G3P. A system for controlling the mixing of two gaseous or liquid streams A, B to produce a mixed stream C of predetermined quality comprises, a meter 2 sensing a property of the stream C, a controller 3 which compares the signal from meter 2 with a set value and provides an output which is fed to multiplier 4 which in turn provides an output representative of the product of the output of controller 3 and that of a flowmeter 1 sensing the flow rate of stream C, and a ratio controller 5 which compares the ratio of signals from a flowmeter 6 and the multiplier 4 with a set value and controls the flow of stream A and/or B. The sensed property of stream C might be viscosity, temperature, octane number, vapour pressure or flash point. It is shown that the gain of the system is independent of the flow rates. If the flow rate of one of the streams A, B is considerably, larger than the other, then flowmeter 1 may be replaced by a meter sensing the larger flow, whilst controller 5 receives a signal from a flow meter in the other stream. A function generator (9) can be installed between meter 2 and controller 3. One or both of the streams A, B may be a mixed stream produced as above or by other methods. |
