| 摘要 |
1,102,426. Integrating apparatus. FOXBORO CO. 4 Oct., 1965 [5 Oct., 1964], No. 42111/65. Heading G4G. [Also in Divisions G1 and H3] Integrating apparatus for totalling the value over a period of a serially variable quantity, e.g. rate of fluid flow, comprises an input 10, 12 (Fig. 1A) receiving a D.C. signal, e.g. from a flow transmitter varying, e.g., 1 to 5 volts over the full flow range, directed over variable calibrating resistance 16 to an input, e.g. solid state amplifier 20 whose other input is returned to an e.g. 1 volt reference voltage and which develops an output of e.g. 1 volt for zero input at no flow, which is connected over diode 32 to calibration switchable capacitor 34 returned to the first input. The output thus repre. senting the time integral of the input (Fig. 2a, not shown) is connected over a resistor 36 to a first input of amplifier 40 whose other input is returned to e.g. 1 volt positive and whose output is connected over calibration switchable capacitor 46 to the first input, whereby the output of the amplifier represents the time integral of its input signal and the second time integral of the input to amplifier 20 (Fig. 2b, not shown). The output is also connected (Fig. 1B) to an input 48 of a transistorized differential amplifier 50 whose other input is supplied from an, e.g., 5 volt positive reference, and when this is exceeded applies a signal to two-stage amplifier 56 and double base transistor 60 firing to discharge a CR circuit 62, 64, and so trigger a one-shot multivibrator 68 whose output pulse is transformer coupled (Fig. 1A) to drive transistors 84, 86 conductive and discharge capacitors 34, 46 simultaneously (Figs. 2A, 2B, not shown) in readiness for further integration; diodes 88, 90 and resistors 92, 94 damping oscillatory swings. It is shown that the frequency of the control pulses is proportional to the square root of the input voltage at 10, 12 and thus to fluid flowrate if the input is proportional to the square of the flow rate as in the usual flow transmitter. Multivibrator 68 also pulses stretching circuit 98 to produce at 100 a relatively long pulse for each multivibrator pulse, which may operate an electromechanical counter (not shown) indicating total of the variable quantity, e.g. flow over a given time. Interference signals at input 10, 12 are eliminated by utilizing each control pulse to initiate a current pulse over diode 102 into the e.g. 1 volt positive reference to negativize the amplifier input for zero flow rate. The corresponding positive output develops a further pulse of current over Zener diode 104 into the 1 volt reference, and the amplifier is locked to negative input and positive output after termination of the control pulse; capacitor 34 being protected by diode 32. When an output signal exceeds, e.g. 0À04 volts integration commences, Zener diode 104 becomes non-conductive and the block is removed; while during . integration Zener diodes 104, 110 co-operate to clamp the amplifier output to + 10 v. Calibration is effected coarsely by selecting capacitors 34, 46 and finely by adjusting resistor 16. |
