Patent GB-1196162-A (GB)
Title: Arrangement for Combining Tobacco Streams
IPC: A24B3/08
Filed: 1967-05-03
Abstract: 1,196,162. Combining tobacco streams. HAUNI-WERKE KÍRBER & CO. K.G. 3 May, 1967 [4 May, 1966; 13 May, 1966; 17 May, 1966], No. 20568/67. Heading A2C. [Also in Divisions A4, B1 and G3] An arrangement for combining in correct amounts tobacco streams being treated in at least one tobacco preparation device and flowing into separate branch paths to a combining point on a timed basis and in a predetermined ratio, is characterized in that a tobacco throughput measuring device is arranged in one feed path upstream of the combining point which device is operatively connected to at least one tobacco flow regulating device in another fed path for regulating the tobacco flow in the latter path. As shown in Fig. 1, tobacco, in two paths 2001, 2002 which each include two tobacco treatment devices 2006, 2007 and 2008, 2009 respectively, is subsequently combined in a mixer 2004 to form a single feed 2003 to a further treatment device 2005. The treatment devices may, for example, be moistening, saucing, cooling, drying, cutting, heating, stripping, bale opening and mixing devices. A flow regulating device 2010 in the first feed path 2001 comprises a feeder 2011 with a following belt weigher 2012 and a regulator 2013 controlled by the weigher 2012. A standard value, determined by a belt weigher 2012 in the second feed path 2002, is also fed to the regulator 2013, and the feeder 2011 which has some storage capacity is thus controlled to supply a tobacco flow of a value determined by the difference between the standard value and the regulator determined value. Delay devices 2015, 2016 are also provided in the feed paths 2001, 2002 to equalize the running periods of the tobacco in the two paths between the devices 2010 and 2014 respectively to the mixing device 2004. Other examples, Figs. 2, 3, 4 (not shown), illustrate the combining of three tobacco streams in which: Fig. 2, in one stream a belt weigher, that precedes two treatment devices that have no effect on the stream flow rate, provides a control signal for flow regulators in the other two streams; Fig. 3, a belt weigher in one stream not only provides a control signal for the flow regulators in the other two streams but also feeds a signal to a tobacco flow regulating device immediately preceding it in the stream, a control signal therefor being provided by the driving means of a following treatment device in the same stream upstream of the combining point; and Fig. 4, the flow rates of two streams are first controlled by the flow rate of a third stream after which all three streams pass through treatment devices and their flow rates are again controlled by the flow rate of the now treated third stream before they are combined into a single stream. An embodiment for cutting tobacco and blending it with ribs, Fig 5, comprises a conveyer 1 that feeds tobacco leaf free from ribs to a tobacco cutter 37 located in the path of a feeder 30 and thence to a combining point 32. A conveyer 2 feeds tobacco ribs via a feeder 31 through a tobacco flow regulating device 41 to the same combining point 32, the combined streams of cut tobacco and ribs then passing to a mixer 33 for subsequent discharge by a conveyer 34. The feeders 30, 31 comprise sets of belts driven in the direction of the arrows by a common motor 35. Conveyers 1, 2 are driven by motors 5, 6 respectively; the relative speeds of the motors 5, 6 being controlled by a bridge circuit 7 in which the moving elements 8, 9 of two potentiometers 8, 9 are adjusted according to the speeds of the conveyers 1, 2 by speed sensing means 1a, 1b. The potentiometer 8 is preceded by a manually adjustable delay circuit 12. Fixed resistors 14, 15 form the other two arms of the bridge 7, current is fed to the circuit through terminals 16, 17 and an output for controlling the speed of the motor 6 is obtained from a variable tapping 19 of a resistor 18 forming the cross member of the bridge 7 which is preset for the desired ratio for the speeds of the motors 5, 6 to provide the desired feed ratio for the tobacco leaf and ribs allowing for the different capacities of the belts of the conveyers 1, 2. The tobacco cutter 37 consists of three units to which an excess of uncut tobacco leaf is supplied, the surplus being returned by a conveyer 36. A maximumminimum photo-cell measuring device 38, in the path of the conveyer 36, is connected to a control unit 39 to adjust the speed of the motor 5 to keep the amount of the returned tobacco within predetermined limits. As the speed of the motor 5 is changed, the speed of the motor 6 is automatically adjusted by the bridge circuit 7 after the preset delay. The throughput of cut tobacco in the feeder 30 is measured by a belt weigher 40 connected to a transducer 53 that provides a control signal for a flow regulating device 44 for the rib tobacco feeder 31. The device 44 includes a belt weigher 43 which, through a transducer 45, provides a signal that in conjunction with a standard value provided by a regulator 50 and the control signal from the transducer 53 adjusts a regulator 52 that controls the speed of the drive 46 of a feeder 42 having storage capacity. In a modification, Fig. 6 (not shown), the delay device 12 is replaced by a delay device (160) connected directly between the speed sensing means 1a and the motor 6, so that the start of the motor is delayed but when it commences running its speed is then controlled directly in accordance with the speed of the conveyer 1, i.e. without any delay being applied to the speed control signal. In another modification, Fig. 7, the control circuit 7 of Fig. 5 is replaced by a digital counter switch 67. Feed belts 61, 62 carry reflector elements 70, 71 for scanning by photo-electric detectors 72, 73 the pulse outputs of which are connected to a reversible counter 79 which converts its pulse inputs a, b into counting steps of opposite sign. The numerical difference in the two series of pulses from inputs a, b at any time controls the emission of a positive or negative signal at an output c which is fed to an amplifier 80 which in turn controls the motor 66. The detector 72 is also connected to a pre-settable counter 81 which emits a cut-off signal to a relay 82 to stop the motor 66 when the preset impulse count is reached. A tobacco flow regulating device, which can be used as the regulating device 2010 of Fig. 1, is illustrated in Fig. 8 and comprises a feeder 202 incorporating storage capacity followed by an inclined conveyer 224 with comb-off rolls 227 to form a tobacco supply of a height supervised by a known photo-electric control, a belt weigher 210 operatively connected to a transducer 209, an addition unit 239, and a control unit 211. The feeder 202 and the conveyer 224 are driven by an electric regulator motor 250 fed from the control unit 211. A standard difference/actual value comparison signal, which is fed to the control unit 211, is produced by the addition unit 239 from the signal produced by the transducer 209 and a standard value signal from a source 208. The source 208 comprises an adjustable potentiometer 240 the input for which may be a signal derived from a transducer associated with a belt weigher in another feed branch, e.g. the belt weigher 2014 in Fig. 1.