Patent GB-1306716-A (GB)
Title: Flow measuring apparatus
IPC: G01F15/02
Filed: 1970-04-30
Abstract: 1306716 Metering; multipliers DANIEL INDUSTRIES Inc 30 April 1970 [1 May 1969] 20894/70 Headings G4A and G4H Each output pulse from a meter (10, 11 ..., Fig. 1, not shown) metering the flow in a pipeline is multiplied by a factor dependent on the pressure and/or temperature in the pipe-line. As described each of the meters metering the flow in pipe-lines (14, 15 ...) and feeding a common pipe-line (22) is connected to one input of an associated multiplier circuit (26, 27 ...), each receiving on another input a pulse train representing for example the pressure in the common pipe-line (22). Each multiplier output is connected to a counter (30, 31 ...) giving the total flow in each pipe-line (14, 15 ...) corrected for any deviations in pressure from a norm. By operation of a valve the flow in any line may be diverted via a test meter (13) having an associated multiplier (29), the output from which is connected to an independent counter (33) and to the counters of all the other meters.  Digitizer.-The measured temperature or pressure signal is applied via a field effect transistor gate 53 (Fig. 2) to an integrator 60 until a counter 72 receiving clock pulses from oscillator 68 reaches its full count when a bistable 64 is set to close the gate 53 and open a further gate 54 through which a reference signal representing a standard pressure or temperature is fed to the integrator. When a level detector 62 is triggered bi-stable 64 is reset, pulses D from the oscillator being fed to the multiplier circuits whilst the bi-stable is set via enabled gate 78. The circuit also generates one X and one Y pulse on conductors 106, 107 at alternate full counts of counter 72 by dividing the output of bi-stable 65 in two by a further bi-stable 80. In a modification in which the signal applied to the integrator on conductor 38 represents pressure a signal representing temperature may be applied in place of the reference signal on conductor 39. Multiplier.-Each pulse from a flow meter triggers a bi-stable in its associated multiplier so that at the next X pulse a further bi-stable 116, 156 ... (Fig. 3) is set to enable a gate 118, 158 ... so that for each meter pulse the pulses D from the digitizer are accumulated in a counter 126, 166 ... which give output pulses at each full count via a monostable 128, 168 to a counter 30, 31.... The next Y pulse resets any set bi-stable. In the multiplier associated with the test meter the X and Y connections are reversed so that bi-stable 180 is set by the Y pulse following a test metering pulse to prime gate 182 to pass pulses from the digitizer, the bi-stable being reset by the next X pulse. This allows the test circuit pulses to be added into one of the accumulators 126, 166... (when an appropriate switch is operated to enable a gate 122, 162 ...) without interfering with pulses from the associated meters. If the flow measured is being corrected for temperature variations a signal (205, Fig. 5, not shown) representing the measured temperature is fed together with a signal from a voltage source through an operational amplifier to modify it to comply with standard measurement tables.  Total flow may be measured in an additional counter (221, Fig. 6, not shown) receiving output pulses from all the multiplier circuits. The digitizer circuit is modified so that pulses from the meters do not coincide in time, by dividing the output of the bi-stable 64 by four in two further bi-stables (Fig. 7, not shown). In another embodiment for metering crude oil flowing in a pipe (300, Fig. 8, not shown) a capacitor probe (302) measures the percentage of oil in the fluid and applies this as a signal to the digitizer circuit. A signal representing temperature is applied in place of the reference voltage to the integrator in the digitizer. In a modification pulses fed to the multipliers when the bi-stable 64 is set may be derived from a second oscillator controlled by a further variable.