Patent GB-924688-A (GB)
Title: Automatic viscometer and process of using same
IPC: G01N11/06
Filed: 1960-09-23
Abstract: 924,688. Viscometers. ESSO RESEARCH & ENGINEERING CO. Sept. 23, 1960 [Dec. 22, 1959], No. 32754/60. Class 106 (2). An automatic oil viscometer comprises a vertical light-transparent capillary tube into which the oil may be drawn, a detector pair positioned near the lower end of the capillary tube and formed by a light source arranged to transmit a light beam through at least a portion of the tube to a photo-electric cell positioned to receive the light beam from the source after passing through at least a portion of said capillary tube, second and third such detector pairs positioned respectively at a middle position and an upper position with reference to the capillary tube, manifold means in direct and open connection with the top of the capillary tube and providing valved conduits for applying vacuum, atmospheric pressure, inert gas and also a solvent for washing the tube, a liquid-tight chamber enclosing the tube to provide a constant temperature bath, and electrical connections between the photoelectric cells and a series of amplifiers and relays of a control chassis arranged to convert signals from said cells into lapsed time data or durations for determining the viscosity of oil drawn into said capillary tube. The oil to be tested is drawn from a bottle 4 into a tube 2 having a capillary portion 7 and enlarged portions 11, 12 and enclosed in a constant-temperature water bath 3. At positions 8, 9, 10 of the tube 2, light sources 14, 15, 16 energized from a source 26 are associated with photo-electric cells 14a, 15a, 16a having output connections 27, 28, 29. The cells 14a, 15a, 16a and, if desired, the sources 14, 15, 16 may be located outside the bath 3 and be operated in conjunction with light-transmitting tubes, e.g. of Lucite. The top of the tube 2 is connected to a manifold 17 having passages leading to pipes 24, 22, 18, 20 connected to low-pressure, atmospheric (venting) pressure, cleaning solvent and inert gas by means of solenoid-operated valves 25, 23, 19, 21 respectively. In operation, the oil is suctionally drawn into the tube 2 until it reaches the level 10 when photo-cell 16a operates to close the vacuum valve 25 and open the venting valve 23. The cells 14a, 15a will have been operated, but initially have no effect. When the oil in its downward movement reaches level 8, it again operates cell 14a which closes the venting valve 23 and opens the suction valve 25 so that oil is again drawn to the level 10 when cell 16a again operates to close the suction valve and controls a circuit to start firstly a 3-minute timing operation and also a second timing operation of 30 seconds at the end of which the bottle 4 is lowered so that the tube 6 is no longer immersed in oil and the oil level in tube 2 becomes stabilized. At this stage a further period of 1 minute is initiated during which the oil drains slightly into the bottle 4. At the end of the period of 1 minute, a drain cup 91, Fig. 4 (not shown), is positioned under the tube 6, and at the end of the 3-minute period vent valve 23 is opened. The oil slowly descends in the capillary tube 2 and on reaching and passing below level 9 causes the photo-cell 15a to operate to set into operation a timing mechanism which is disabled by photo-cell 14a when the oil reaches and passes below the level 8. The period of operation of the timing mechanism for the passage of the oil from level 9 to level 8 is translated into a measure of the oil viscosity which is displayed or printed on the bottle 4 from which the sample was taken. A control system for the operation of the valves 19, 21, 23 and 25 and a valve-controlled fluid-pressure system for the lowering of the bottle 4 and the introduction of the cup 91 below the tube 6 is described in connection with Fig. 4 (not shown). A further diagrammatic arrangement, Fig. 5 (not shown), indicates how a sample is subjected to successive measurements at two much different temperatures with appropriate arrangements for lifting and lowering the bottle, conveying it between the separate measuring devices, and effecting the printing of the results obtained. A further diagrammatic arrangement, Fig. 6 (not shown), indicates generally how the printing of the indication on to a bottle 4 is effected as a result of the operation of the timing mechanism. General operation, Figs. 7, 8, 9. When a bottle 4 has been positioned below tube 2 the closure of a switch 124 operates a relay 123 which locks up and applies current via relay 120 to operate vacuum solenoid 25 so that oil is drawn into the tube 2 and operates via photo-cells 14a, 15a, 16a associated relays 14d, 15d and 16d, the latter relay operating relay 120 to cut-off the valve 25 and to operate vent solenoid 23 which allows the oil to drop. Relay 120 also actuates relay 121 which is locked. As the oil flows downwardly relay 16d releases, but relay 120 is not released, and as the oil level continues to fall, relay 15d releases but without effect on relays 120, 121. When relay 14d releases relay 120 releases and relay 122 becomes energized and locks up. The release of relay 120 de-energizes vent solenoid 23 and re-energizes vacuum solenoid 25 so that oil is again drawn into the tube 2. Relay 14d is again energized and the larger current in amplifier 14c applies a positive voltage to point B of a count gate control amplifier 126. Relay 15d is again energized without effect on other relays, but amplifier 15c applies a positive voltage to point A of amplifier 126, and when the oil reaches the level 10, relay 16d is energized and the vacuum solenoid 25 is deenergized. Relays 120, 122 operate the 3- minute timer circuit 129. After 30 sees. bottledown timer circuit 130 is energized, illuminates lamp 131, and via lead 76 operates a valve 79 so that the bottle is dropped below the end of the tube 6. Also switch 125 is closed and switch 124 opened. At the end of 1 minute the circuit 129 operates valve 77 so that the pan 91, Fig. 4 (not shown), is rotated to a position under the tube 2. After 3 minutes the relay 129 operates vent release relay 128 which operates the vent solenoid 23 to allow oil to fall in the tube 2 and also prepares counter relay 132 to control the operation of counter 126, 137. When the oil passes below detector 15a, relay 15d releases and reduced voltage from amplifier 15c at input A to circuit 126 actuates the counter relay 132 to permit the operation of the counter. When the oil reaches and falls below the level 8, relay 14d releases and amplifier 14c restores to zero the second input B to amplifier 126 so that the counting operation is discontinued. In the printing control circuit, Fig. 8, pulses from a 200 c.p.s. source 133 are divided by binary circuits 134, 135, 136 and applied through section 126 of the counter, when opened by positive potential at input B, and through a section 137 controlled by circuit 132 to the sections 138, 139 of a control circuit 138, 139 which permits a power source 105 to actuate a printer-control member 102 until zero voltage at B closes the circuit 126 to the 25 c.p.s. driving pulses. The release of relay 132, Fig. 7, initiates the action of a print timer 143 which operates a printing shoe or hammer 142, and at the end of 10 sees. brings into action a reset timer 144, which after about 20 sees. operates a resetting device 146 controlling a reset motor 145 to restore the printer to normal. The reset timer 144 also operates a switch 147, Fig. 9, which operates a solvent timer 148 to open valve 19 to allow solvent to flow for 2-3 mins., and at the end of this time operates an inert-gas timer 149 to open valve 21 to pass gas, for example, nitrogen or carbon dioxide, through the tube 2 for a period of 2-3 minutes after which the cleaning operation is terminated and the apparatus is restored to normal.