GB1342444A - Apparatus for providing signals corresponding to passage of a column of a liquid - Google Patents

Abstract

1342444 Pulse circuits; time delay circuits TEXACO DEVELOPMENT CORP 8 March 1972 10687/72 Heading H3T [Also in Division G1] Viscosity measuring apparatus supplies two spaced signals the spacing being representative of a time of passage. Detectors 18, 19 are connected to respective amplifiers 22, 23, and trigger circuits 24, 25 for controlling logic circuit 28, the state of which is indicated by lamps 29, 30. The logic circuit controls relay driver 33 and thence relay 34, which provides timed input signals to computer input 37. Detector amplifiers.-Each detector 18, 19 is a photocell 45, Fig. 2, connected to an FET phase splitter 41 feeding emitter follows 56, 57 provided with a diode OR-gate 76, 77 to pass positive going signals to output 82. Logic circuit 28, Fig. 3.-This circuit is actuated first only by trigger 24 (on input 85) to produce a first pulse at output 118, and subsequently to respond only to an output from trigger 25 (on input 86), producing a second pulse at 118, after which subsequent trigger pulses at 85, 86 have no effect until the circuit has been reset by switch 110. On receipt of the first trigger input at 85, SCR 92 (in reset condition being off) is switched on (lamp 96 being illuminated thereby). This results in SCR 100 (in reset condition being off) being switched on, a negative pulse via capacitor 107 causing SCR 106 (in reset condition being on) to be switched off. A positive pulse results through capacitor 115 and diode OR circuit 119, 120 to apply a signal to the relay drive on 118. The subsequent trigger pulse on input 86 results in switching on of SCR 106 and switching off of SCR 100 (via capacitor 107). A resultant positive pulse passes via 127 and OR gate to the relay driver. Before initiating a subsequent measurement sequence, the circuit is reset by 110. Relay driver, 33, Fig. 4.-Signals on 138 switch on SCR 141 which switches off SCR 142 and energizes relay 149 to close contact 150. After a delay timed by 155, 158, unijunction 145 actuates SCR 142, to turn off SCR 141 and terminate energization of relay 149.