首页>
外国专利>
Improvements in controllers for maintaining proportionality or substantial proportionality between the variations of a pair of variables
Improvements in controllers for maintaining proportionality or substantial proportionality between the variations of a pair of variables
展开▼
机译：改进了控制器，以保持一对变量的变化之间的比例关系或基本比例关系
展开▼
页面导航
摘要
著录项
相似文献
摘要
717,363. Pressure gauges. BABCOCK & WILCOX, Ltd. May 20, 1952 [May 22, 1951], No. 12743/52. Class 106 (2). [Also in Groups XXXVII and XXXVIII] Apparatus for maintaining proportionality between the quantity of pulverized fuel and the air supply to a furnace burner comprises electrical means for measuring the two quantities, and comparing them in a circuit which produces an output voltage which affects the speed of a motor controlling the fuel supply. The air supply is delivered by a fan 10, Fig. 1, through conduit 11, and the fuel supply is fed by a motor 60 through a pipe 16. The rate of flow of air is determined by a pitot tube arrangement comprising pairs of apertured tubes 13, 14, 13SP1/SP, 14SP1/SP; Fig. 2, across the direction of flow, the up pressure being delivered by a tapping 24 to the interior of a bellows 25 in a sealed compartment 26 fed with the down pressure by a tapping 23. Thus the expansion of bellows 25 is proportional to the rate of flow of air in conduit 11 and a similar arrangement causes a bellows 35 to respond to the rate of flow of fuel in pipe 16 Each bellows 25, 35, is attached to a magnetic plunger 29, 39 movable in energized coils 40, 45 which are connected in series with the primary winding of a transformer 50, 55 to produce a proportionate D.C. voltage across a resistor 62, 64 after amplification and rectification at 61, 63 respectively. The algebraic difference of these voltages; together with a bias voltage obtained from a potentiometer 67 across a battery 68 is applied as a control voltage to the motor 60 controlling the fuel feed, via leads 71, 72. The control circuits, Figs. 4, 5, are fed from secondary winding ST-1 of a mains transformer.T-1. The motor 60 has a shunt field winding SHF fed withthe rectified secondary voltage via diodes 86, and. a series field. winding SF in series with: the armature 60A fed from two thyratrons 90 whose anodes are connected to opposite ends of winding ST-1, the grid, potentials; being determined by the secondary winding ST-3 of a transformer T-3 whose primary winding PT-3 is the diagonal of a bridge 80 also connected across the winding ST-1, the bridge comprising three fixed resistors and a coil 84 which is the power coil of a saturable reactor having control coil 85. The control voltage at leads 71, 72 biases a valve 105 to control the anode current of valve 100, and hence the anode current of valve 110 having control winding 85 in its cathode lead. This in turn affects the impedance of power coil 84 in the bridge 80, to control the phase and magnitude of the current in primary winding PT-3 and secondary- ST-3, thereby controlling the conducting time of thyratrons 90, and hence the, average current through the armature 60A of motor 60. Relays A, B, C, D, E and F ensure proper time sequence of connections at starting, indicated by coloured lamps R, G. In a modification the control voltage is fed to the motor through two magnetic amplifiers.
展开▼
