US3794049A

US3794049A - Method and apparatus for processing tobacco

Info

Publication number: US3794049A
Application number: US00231251A
Authority: US
Inventors: W Wochnowski
Original assignee: Hauni Werke Koerber and Co KG
Current assignee: Koerber AG
Priority date: 1971-03-13
Filing date: 1972-03-02
Publication date: 1974-02-26
Anticipated expiration: 1991-02-26
Also published as: CA963342A; GB1382277A; DE2112211A1; DE2112211B2; DE2112211C3; JPS5715873B1; IT953489B; FR2129391A5

Abstract

A tobacco processing apparatus wherein a battery of shredding machines delivers tobacco shreds to a hopper from which a constant stream of tobacco shreds is being withdrawn by an adjustable weighing device. The tobacco stream is conveyed past a series of treating units including a drying unit, a flavoring unit and a storing unit. A main set value potentiometer is adjustable to produce signals which are used for delayed adjustment of the treating units, for direct adjustment of the weighing device and for indirect and/or direct adjustment of one of the shredding machines. Each treating unit is further adjustable by an auxiliary set value potentiometer. A second type of tobacco is being mixed with tobacco shreds at a rate which varies in response to signals from the main set value potentiometer.

Description

United States Patent 9 wochnowski 1451 Feb. 26,1974

[ METHOD AND APPARATUS FOR 3,494,507 2/1970 Ricciardi....., 198/39 x PROCESSING TOBACCO 3,430,751 3/1969 Bateson 198/39 [75] Inventor: Waldemar Wochnowski, FOREIGN PATENTS OR APPLICATIONS fiamburg-Meiendorf, Germany 1,532,065 1/1970 Germany 131/135 [73] Assignee: Hauni-Werke Korber & Co. KG,

Hamburg, Germany Primary Examiner-Wm. H. Grieb Assistant Examiner-John F. Pitrelli [22] Flled: 1972 Attorney, Agent, or Firm--Michael S. Striker [21] Appl. No.: 231,251

[57] ABSTRACT [30] Foteign Application Prim'ity A tobacco processing apparatus wherein a battery of Mar. 13, 1971 Germany P 21 12 211.2 Shredding machines delivers tobacco shreds to a hop. per from which a constant stream of tobacco shreds is 1 Cl 131/21 131/22 being withdrawn by an adjustable weighing device.

198/39 The tobacco stream is conveyed past a series of treat- 1 hiltunits including a unit a flavoring unit and a Field 131/21 22 storing unit. A main set value potentiometer is adjust- 131/144, 21 R, 22 177/19, 21 able to produce signals which are used for delayed adjustment of the treating units, for direct adjustment of References Cited the weighing device and for indirect and/or direct ad- UNITED STATES PATENTS justment of one of the shredding machines. Each 3,539,316 11/1970 Trethewey 198/39 x "eating unit is further adjustable y an auxiliary Set 3,590,826 7/1971 Wochnowski et a1. 131/108 x value potentiometer A econd type of tobacco is 2,533,550 12/1950 Blackwell 83/73 X being mixed with tobacco shreds at a rate which varies 3,052,242 9/1962 Levadi 131/21 D in response to signals from the main set value potenti- 3,389,707 6/1968 Wochnowski.. 131/135 ometef 3,419,015 12/1968 Wochnowski.. 131/135 X 2,827,058 3/1958 Bogaty 131/108 29 Claims, 7 Drawing Figures PMENTEB FEB 2 61974 sum 1 or 7 PATENTEB FEBZS 1974 I SHEET 2 (IF 7 Ali ANN

PMENIEQ FEB 2 s m SHEET u 0F 7 i PAIENTEB FEB26 I974 SHEET 5 0F 7 METHOD AND APPARATUS FOR PROCESSING TOBACCO BACKGROUND OF THE lNVENTlON The present invention relates to a method and apparatus for producing tobacco, and more particularly to a method and apparatus for subjecting one or more types of tobacco to a plurality of different treatments. Still more particularly, the invention relates to a method and apparatus for subjecting one or more tobacco streams to a variety of treatments which may include shredding, mixing of two or more tobacco types, changing the moisture content, contacting tobacco with one or more liquid flavoring or analogous agents, changing the volume of tobacco particles, storing and- /or many others.

The processing of tobacco, particularly certain types of treatment, is a complex operation due to the fact that the dimensions, moisture content and certain other characteristics of untreated tobacco vary within a very wide range, the same as the characteristics of many other commodities which are grown rather than manufactured. Thus, the leaves of tobacco must be subjected to a cleaning, destalking, shredding moisture changing, flavoring, blending, metering and/or other treatment in order to arrive at a consistency which is satisfactory for conversion of the thus treated tobacco into fillers of cigarettes, cigars or cigarillos. ln presently known tobacco processing plants, the operation of treating or processing units which are employed to comminute, flavor, heat, moisturize, cool and/or otherwise condition tobacco must be adjusted-individually in dependency on the characteristics of tobacco as well as in dependency on the rate at which tobacco is being supplied to and transported past or through such units. This necessitates the utilization of complex control systems which must be supervised and manipulated by a large number of attendants. Thus, whenever it becomes necessary to change the rate of tobaco transport and/or to change the type or types of tobacco to be treated, each treating unitmust be adjusted individually so that each conversion of the apparatus for the processing of different types of tobacco and/or a change in the throughput of tobacco invariably necessitates prolonged interruptions of operation with attendant losses in output. Furthermore, the accuracy manual adjustment of a host of treating units depends on the skill and conscientiousness of attendants so that substantial quantities of tobacco can go to waste if the adjustment of a single treating unit is inaccurate, i.e., not in proper relationship with adjustments of the other treating unit or units.

For example, it is highly desirable to insure that a treating unit which changes the moisture content of tobacco of a treating unit which contacts the particles of tobacco with casing or another liquid flavoring agent should receive tobacco at a constant rate, particularly at such a rate that the weight of each unit length of the tobacco stream which is being conveyed toward, through and beyondeach treating unit does not vary at all or varies within an extremely narrow range. On the other hand, the output of a tobacco shredding machine is likely to vary (and normally varies) even if the inlet of such machine receives tobacco leaves at a constant rate. Thus, if the output of one or more shredding machines is to be fed into a tobacco heater or an analogous treating unit whose operation is strongly affected by fluctuations in the rate of tobacco transport thereto, it is necessary to provide in the path between the shredding machine or machines and the tobacco heater or an analogous treating unit some means for equalizing or uniformizing the rate of tobacco flow in order to compensate for fluctuations in the output of the shredding machine or machines.

SUMMARY OF THE INVENTION An object of the invention is to provide a novel and improved method of processing tobacco according to which the intensity of treatment of tobacco at one or more processing or treating stations need not be changed in response to changes in the rate at which the tobacco is being transported toward, past or through and beyond such station or stations.

Another object of the invention is to provide a novel and improved method of automatically subjecting one or more tobacco types to a large number of widely different treatments each of which can be regulated independently of the others and all of which can be regulated from a single control point or station.

A further object of the invention isto provide a novel and improved method of insuring that the rate of tobacco transport to and beyond those stations where the nature of treatment is adversely affected by fluctuations in the rate of tobacco feed remains unchanged as well as that the intensity of treatment at such stations is changed automatically if and when it becomes desirable to change the throughput of tobacco.

An additional object of the invention is to provide an automatic tobacco processing apparatus which can be utilized for the practice of the above outlined method and whose operation can be supervised and/or regulated by a single attendant even if the apparatus is designed to subject tobacco to a large number of widely different treatments.

Still another object of the invention is to provide a tobacco processing apparatus wherein eventual fluctuations in the rate at which tobacco is being discharged at one or more treating stations cannot influence the operation of those treating units whose operation is adversely affected even by minor variations in the rate of tobacco delivery thereto.

The method of the present invention comprises the steps of transporting at least one stream of tobacco along an elongated path past a plurality of treating stations including at least one first station which is located upstream and at least one second station which is located downstream of a predetermined intermediate section of the path, subjecting the tobacco stream in such intermediate section to a variable metering equalizing action so that each unit length of the tobacco stream downstream of the intermediate path section normally contains identical quantities of tobacco (preferably identical quantities per weight), adjusting the treatment of tobacco at the second station in response to variations of the metering action, monitoring the rate of tobacco transport between the intermediate path section and the first station, and adjusting the treatment of tobacco at the first station as a function of variations of such rate of tobacco transport. Thus, if the station or stations at which the output of tobacco is likely to fluctuate are placed upstream of the intermediate path section, and the stations at which the treatment of tobacco is adversely affected by fluctuations in the rate of tobacco delivery thereto are placed downstream of the intermediate path section, eventual fluctuations in the output of tobacco at the first station or stations cannot have any effect upon the treatment of tobacco at the second station or stations because the tobacco is subjected to a metering action before it reaches the second station or stations.

The adjustment of the treatment of tobacco at each second station preferably takes place in direct response to variations of the metering action (such metering action can be changed by resorting to an adjustable potentiometer or other suitable set value selector means), and the method preferably further comprises the step of delaying the adjustment of treatment at each second station until the leading end of the altered tobacco stream which leaves the intermediate path section subsequent to a variation in the metering action reaches the respective second station. This insures that the intensity of treatment of tobacco at each second station is adjusted only to the extent which is necessary to take into consideration the changed rate of tobacco transport toward, through or past and beyond such second station. The treatment of tobacco at the first station or stations may be adjusted in direct and/or indirect re sponse to variations in the metering action; such adjustment serves to guarantee that the intermediate path section invariably receives tobacco at a rate which is necessary to insure that the selected throughput of tobacco in the path downstream of such section remains constant.

It is normally preferred to build up the intennediate path section a relatively small supply of tobacco which arrives from the first station, and the step of subjecting the tobacco stream to a variably metering action then comprises withdrawing tobacco at a selected one of a plurality of rates from such supply in the intermediate path section. The monitoring step then preferably comprises scanning the supply of tobacco in the intermediate path section, and the step of adjusting the treatment of tobacco at the first station comprises changing the output of treated tobacco at the first station when the quantity of tobacco in the supply is without predetermined range. The first station may accommodate one or more shredding or analogous comminuting machines whose output can be regulated by changing the rate of tobacco feed thereto. Thus, the treatment of tobacco at the first station may involve adjusting the quantity of comminuted tobacco which leaves the first station and is being delivered into the range of the metering unit in the intermediate path section.

The method may further comprise the steps of feeding to the first station tobacco to be comminuted at a rate exceeding the tobacco requirements at the first station so as to establish and maintain a fluctuating surplus of tobacco to be comminuted at the first station, measuring the quantity of tobacco which forms such surplus, and changing the rate of feed of tobacco to the first station in dependency on the fluctuation of such surplus.

The treatment of tobacco at one or more second stations may comprise admixing to the tobacco streams at least one second type of tobacco at a rate which varies proportionally with variations of the metering action. However, the unit which delivers the second type of tobacco is preferably further adjustable independently of such changes in the rate of delivery of second tobacco type which are desirable when the metering action in the intermediate path section is changed.

The treatment at one or more second stations may comprise changing the moisture content of tobacco, storing the tobacco of the stream to form a'floating store of tobacco and withdrawing tobacco from such floating store at a rate which varies proportionally with variations in the metering action, and/or contacting successive increments of the tobacco stream with at least one flavoring agent (this term is intended to em brace liquid casing) at a rate which varies proportionally with the variations of the metering action.

The treatment of tobacco at one or more first stations and/or one or more second stations can be adjusted or altered independently of variations of the metering action in the intermediate path section. The instrumentalities (e.g., one or'more potentiometers or analogous set value selectors) for carrying out adjustments of the metering action are preferably placed in close proximity of instrumentalities (e.g., potentiometers or analogous auxiliary set value selectors) which are utilized for carrying out independent adjustments of tobacco treatment at one or more first and/or second stations.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved tobacco processing apparatus itself, however, both as to its construction and its mode of operation, together, with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments withrefer ence to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. l is a diagrammatic view of a tobacco processing apparatus which embodies one form of the invention;

FIG. 2 is a partly diagrammatic plan view of tobacco treating units which are adjacent to the path for tobacco upstream of the metering unit;

FIG. 3 is a partly schematic side elevational view of the metering unit and a perspective view of one of the comminuting machines which deliver tobacco shreds to the metering unit;

FIG. 4 is a partly diagrammatic elevational view of a tobacco heating or drying unit in the apparatus of FIG.

FIG. 5 is a partly diagrammatic elevational view of the tobacco flavoring and storing units in the apparatus of FIG. 1;

FIG. 6 is a diagrammatic view of a second tobacco processing apparatus; and

FIG. 7 is a fragmentary diagrammatic view of a third tobacco processing apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. I, there is shown a tobacco processing apparatus having a transporting system which includes a set of driven

conveyor belts

1, 2, 3, 4, 6 defining an elongated primary path A wherein particles of tobacco travel toward, through and beyond a series of treating or processing stations B, C, D, E, Fand G. Each of the stations B, D, E, F, G accommodates a tobacco treating or processing unit. The apparatus further comprises a metering or equalizing unit 7 which is located in an intermediate portion or section A of the path A, namely, downstream of the treating stations B, C but upstream of the treating stations D, E, F and G. The purpose of the metering unit 7 is to deliver to the downstream portion of the path A a stream of tobacco shreds 27 (see FIG. 2 or 3 wherein each unit length contains the same amount per weight. The treating station D is adjacent to a secondary path or branch path A, which merges into the primary path A at a point 106 located downstream of the path section A. The path A delivers to the path A a constant stream of comminuted tobacco ribs which are to be mixed with the shreds 27. The secondary path A is defined by one or more endless conveyor belts 8.

The first treating station B accommodates a comminuting unit 9 for stripped or stemmed tobacco leaves 19 (see FIG. 2), and the treating station C accommodates a tobacco leaf feeding unit 12. The comminuting unit 9 comprises a battery of four tobacco shredding machines Ila, 11b, 11c, 11d which are arranged in parallel, and the purpose of the feeding unit 12 is to supply tobacco leaves 19 to the inlets of the shredding machines 11a-l1d. The units 9 and 12 are illustrated in greater detail in FIG. 2, and the shredding machine 11d is further shown in a perspective view in FIG. 3.

The treating station D accommodates a tobacco stem or rib feeding unit 13 the details of which are shown in the upper right-hand portion of FIG. 1. The details of a heating or drying unit 14, which is accommodated at the treating station E, are shown in FIG. 4. FIG. 5 shows the details of a tobacco flavoring unit 16 and of a tobacco storing unit 17 which are respectively accommodated at the treating stations F and G. The details of the metering or dosing unit 7 are shown in FIG. 3.

Referring to FIG. 2, the tobacco shredding machines lla-lld of the comminuting unit 9 are of similar or identical construction and their parts are denoted by similar reference numerals followed respectively bythe characters a, b, c and d. Each of these shredding macinnes may be'of the type known as KT produced by Hauni-Werke, Kiirber & Co. K.G., of Hamburg- Bergedorf, Western Germany. It is assumed that all four shredding machines Ila-11c receive destalked tobacco leaves 19 at a constant rate. The operation of the fourth or last shredding machine IId is regulated by a control circuit 28 in response to signals from a photosensitive detector or monitoring means 66 (FIG. 3) in the metering unit 7. The conductor which transmits signals from the detector 66 to the control circuit 28 is shown at 30.

The shredding machines Ila-11d respectively comprise tobacco leaf admitting and compacting ducts 18a, 18b, 18c, 1811 which receive destalked or stemmed tobacco leaves 19 from the conveyor belt I. The shredding machine IId comprises two endless tobacco leaf compacting and advancing

chains

21d, 22d which are driven by a d-c motor 23d and convert the stream of tobacco leaves furnished by the duct 18d into a cake which moves through and beyond an adjustable mouthpiece 24d and into the range of orbiting knives (not specifically shown) provided on a rotor which is driven by an electric d-c motor 26d. The knives slice the cake to form tobacco shreds 27 which are discharged onto the conveyor belt 2 for transport toward the metering unit 7. The corresponding parts of the shredding machines lla-l 1c operate in the same way as the just described similarly'referenced parts of the machine 11d.

includes a conventional tachometer generator 29 which is kinematically connected with the d-c motor 23d so as to produce signals which'are indicative of the momentary speed of the motor 23d. Such signals are transmitted to the input a of a signal comparing circuit or junction 31 which has a second input b connected with a potentiometer 32 whose sliding contact is adjustable as a function of changes in the cross-sectional area of mouthpiece 24c in the shredding machine 11d. Thus the signal from the potentiometer 32 to the input b of the junction 31 is representative of the cross-sectional area of the cake which is being formed by the

chains

21d, 22d and is being fed into the range of knives which are driven by the motor 26d. One portion of the mouthpiece 24d is connected to one of the

chains

21d, 22d and such one chain is adjustable relative to the other chain in dependency on the compactness of tobacco leaves which form the cake. Reference may be had to the copending application Ser. No. 141,164 filed May 7, 1971 by Uwe Eisner which describes tobacco shredding machines embodying adjustable mouthpieces.

A third input c of the junction v31 receives signals from the aforementioned monitoring means or detector 66 by way of the conductor 30, and such signal is indicative of the quantity of tobacco shreds in a hopper 63 of the metering unit 7. The output of the junction 31 is connected with an output amplifier 33 which controls the speed of the motor 23d for the

chains

21d, 22d. It is clear that the control circuit 28 can be associated with the shredding machine Ila, b B or 110, or that the output of several shredding machines can be regulated for the purpose of insuring that the quantity of tobacco shreds 27 in the hopper 63 of the metering unit 7 remains within a desired range.

A carded tobacco leaf feeding unif lz of FIG. 2 comprises a magazine or source 44 for destalked tobacco leaves 19, acarded feeder belt 43 which withdraws a stream of tobacco leaves from the magazine 44 and delivers themqto the conveyor belt 1 for transport to the ducts 18d-18d of the shredding machines 114-114, and a d-c motor 42 which drives the feeder belt 43 at a variable speed. A recycling conveyor system of the feeding unit 12 comprises

endless conveyor belts

47, 48, 49 which serve to return the surplus 37 of tobacco leaves 19 from the discharge end of the belt 1 to the magazine 44. As shown in FIG. 2, the shredding machines lla-lld are provided with deflectors each of which overlies a different portion of the upper stretch of the belt 1 to direct a substantially constant quantity of tobacco leaves 19 into the

respective duct

18a, 18b, 18c or 18d. The details of a similar comminuting unit are described in the aforementioned copending application Ser. No. l4l,l64 of Elsner.

The operation of the d-c motor 42 for the carded feeder belt 43 is controlled by a regulating circuit 34 which forms part of the feeding unit 12 and comprises an adjustable potentiometer 36 constituting a rated or set value selector which serves to deliver to a signal comparing circuit or junction 39 a signal which is indicative of the desired quantity of tobacco leaves 19 which are to form the surplus 37. The actual amount of tobacco leaves 19 in each unit length of the stream forming the surplus 37 is detected by a weighting device here shown as a belt scale 38 which is installed between two spaced portions of the conveyor belt 48 and is associated with a suitable transducer (not shown) serving to transmit to the junction 39 signals which indicate the weight of tobacco leaves 19 per unit length of the surplus stream 37. The junction 39 further receives signals from a tachometer generator 46 which monitors the speed of the motor 42. The signal from the junction 39 is amplified by an output amplifier 41 and is used to regulate the speed of the motor 42, i.e., the rate at which the feeder belt 43 delivers tobacco leaves 19 from the magazine 44 to the belt 1 for admission into the ducts l8a-18d and to the conveyor belt 47. The motor 42 drives the feeder belt 43 as well as a further conveyor belt (not specifically shown) whose upper stretch constitutes the bottom wall of the magazine 44 and serves to move tobacco leaves 19 in the magazine 44 into the range of the carding on the belt 43. The manner in which the magazine 44 receives tobacco leaves from one or more stemming machines of from a main magazine is not shown in FIGS. 1 and 2. The signal which is furnished by the tachometer generator 46 to the junction 39 serves to prevent any changes in the speed of the motor 42 when the latter is operated at a desired speed.

The details of the metering or dosing unit 7 are shown in H0. 3. This unit comprises a weighting device in the form of a belt scale 61 which receives tobacco shreds 27 from a relatively small supply 64 accumulated in the hopper 63. The latter comprises a stationary inclined wall 73 and an endless carded belt 62 which is driven at a variable speed and has an upwardly inclined stretch which delivers a stream of shreds 27 from the supply 64 onto the upper stretch of an endless belt or band 83 forming part of the weighting device 61. The aforementioned conductor 30 is connected with a signal transmitting circuit 71 which receives signals from the photoelectric cells 67, 68, 69 of the detector 66 in the hopper 63. The uppermost cell 67 furnishes a signal when the supply 64 in the hopper 63 rises to a level at which the uppermost layer of tobacco shreds 27 interrupts the light beam between the light source and the photosensitive element of the cell 67. The median cell 68 furnishes a signal when the supply 64 rises to a median or average level and the lowermost cell 69 produces a signal when the supply 64 descends to a level at which the beam issuing from the light source of the cell 69 can reach the respective photosensitive element. The circuit 71 transmits to the junction 31 of the control circuit 28 for the shredding machine 11d of FlG. 2 signals which are indicative of the quantity of tobacco shreds 27 in the hopper 63, and the circuit 28 regulates the output of the shredding machine lld in such a way that the output of this machine increases in response to a signal from the cell 69 but decreases in response to a signal from the cell 67. The reference character 72 denotes a motor-driven endless carded belt having an upwardly inclined stretch while transports tobacco shreds 27 from the conveyor belt 2 into the hopper 63.

It will be noted that the detector 66 constitutes a means for monitoring the rate at which the comminuting unit 9 delivers tobacco shreds 27 to the metering unit 7 by detecting the quantity of tobacco shreds which form the supply 64 in the hopper 63.

The endless band 83 of the weighing device or belt scale 61 is trained over rollers mounted on an elongated carrier or arm 77 which is fulcrumed in a stationary frame (as at 76) at one end and the other end of which is connected with a helical spring 74. The latter tends to pivot the carrier 77 in a counterclockwise direction, as viewed in FIG. 3, so that the spring 74 opposes the tendency of the carrier 77 to pivot clockwise under the weight of tobacco shreds 27 on the upper stretch of the band 83. The carrier 77 is connected with the sliding contact78a of a potentiometer 78 which transmits signals to a signal multiplying circuit 79. The signals from the potentiometer 78 are indicative of the angular position of the carrier 77 and hence of the weight of a unit length of the stream of tobacco shreds 27 on the band 83. The multiplying circuit 79 multiplies the signal from the potentiometer 78 with a signal which is supplied by a tachometer generator 81 serving to monitor the speed of a d-c motor 82 which drives the carded belt 62 of the hopper 63 and the band 83 of the weighing device 61. The output signal from the multiplying circuit 79 is transmitted to one input of a signal comparing circuit of junction 84 whose output signal is amplified by an output amplifier 87 and is used to regulate the speed of the motor 82. The junction 84 further receives signals from a main rated or set value selector 86 here shown as a potentiometer which can be adjusted by hand or otherwise to furnish to the junction 84 signals which are indicative of the desired throughput, i.e., of the desired rate of feed of tobacco shreds 27 from the supply 64 in the hopper 63 to the conveyor belt 3. The motor 82 constitutes a means foradjusting the weighing device 61 of the metering unit 7 in response to signals which are generated on actuation of the main set value potentiometer 86. The signals which are furnished by the main set value potentiometer 86 are further transmitted by way of a conductor 88 and serve to regulate the operation of certain parts of the units at the treating stations D, E, F and G. The construction and mode of operation of a metering unit which is similar to the metering unit 7 of FIG. 3 are de scribed in German printed publication No. l,9l4,466.

When the person in charge decides to adjust the main set value potentiometer 86 to thereby change the weight of tobacco shreds 27 which are being withdrawn from the supply 64 in the hopper 63 per unit of time, the altered signal is transmitted to the junction 84 without delay and to the

units

13, 14,16, 17 at the stations D, E, F, G with an appropriate delay in order to insure that the treatments to which the tobacco is subjected.

at such stations remain unchanged even though the respective stations receive tobacco shreds 27 at the newly selected rate. it will be seen that any changes in the signal furnished by the main set-value potentiometer 86 are transmitted to the

units

13, 14, 16, 17. directly (by way of the conductor 88) and that the units 9, 12 at the stations B, C which are located upstream of the path A are influenced by the altered signal from the main set value potentiometer 86 in an indirect way. This is due to the fact that the operation of the shredding machine lid in the comminuting unit 9 is altered in response to changes in the quantity of tobacco shreds 27 which form the supply 64; such changes, in turn, will invariably occur if the main set value potentiometer 86 is adjusted so as to cause the carded belt 62 to remove tobacco shreds 27 from the hopper 63 at a higher or lower rate. As mentioned before, the signals which are transmitted by way of the conductor 30 could be used to regulate the output of one of the shredding machines Ila-11c of the output of two or more shredding machines in the comminuting unit 9.

The tobacco stem or rib feeding unit 13 of FIG. 1 comprises a source or magazine 101 for a supply of comminuted tobacco ribs or stem. It is clear, however, that the magazine 101 can be used to store a supply of a different type of tpbacco, for example, shreds of Oriental tobacco which are to be blended with shreds of Virginia, Burley, another domestic tobacco, and/or shredded reconstituted tobacco. The magazine 101 delivers comminuted tobacco ribs or stem to a metering or dosing device 102 whose function is analogous to that of the metering unit 7, i.e., it is intended to deliver to the conveyor belt 8 comminuted tobacco ribs or stem at a constant rate depending on the setting of the main set value potentiometer 86. The conductor 88 transmits signals from the main set value potentiometer 86 to a time delay relay 104 which is connected with a signal comparing circuit or junction 103 by way of an adjustable set value potentiometer 107. The time delay relay 104 is adjusted in such a way that the delay with which a first different unit quantity of comminuted ribs or stem (in response to an adjustment of the main set value potentiometer 86) reaches the point 106 where the secondary path A merges into the primary path A equals the delay with which the first altered unit quantity of tabacco shreds 27 delivered by the band 83 of the weighing device 61 reaches the point 106. This insures that the ratio of ribs or stem to shreds in the combined tobacco stream which moves along the primary path A beyond the point 106 remains unchanged even if the operator decides to adjust the main set value potentiometer 86 (unless, of course, the operator also decides to adjust the set value potentiometer 107 which thereby changes the ratio of comminuted ribs or stem to shreds 27 in the primary path A downstream of the point 106).

The signal from the junction 103 is amplified by an output amplifier 108 which determines the speed at which a d-c motor 109 drives a carded feeder belt 111 forming part of a hopper 112 which receives comminuted ribs or stem from the magazine 101. The carded belt 111 delivers comminuted ribs or stem onto the upper stretch of a band (not specifically shown) forming part of a weighing device or belt scale 113 similar to the weighing device 61 of FIG. 3. The carrier of the weighing device 113 is pivotable in the same way as the carrier 77 of FIG. 3 and controls the slider of a potentiometer 114 which transmits signals to a signal multiplying circuit 1 16. The latter further receives signals from a tachometer generator 117 which monitors the speed of the motor 109. The output signal from the circuit 116 is transmitted to the junction 103. The signal from the circuit 116 to the junction 103 is indicative of the actual rate of delivery of comminuted ribs or stem to the conveyor belt 8, i.e., to the point 106 where the secondary path A merges into the primary path A.

A photoelectric detector 118 in the hopper 112 transmits signals to a junction 1 19 which is further connected with an adjustablepotentiometer 121 constituting a rated or set value selector. The signal from the junction 119 is amplified by an output amplifier 122 and is utilized to regulate the speed of a d-c motor 123 which drives a feeder serving to transport comminuted ribs or stem from the magazine 101 into the hopper 112. A tachometer generator -124 monitors the speed of the motor 123 and transmits signals to the junction 119. The feeder which is driven by the motor 123 may include an endless belt (not specifically shown) whose upper stretch constitutes the bottom wall of the magazine 101. The signal from the tachometer generator 124 to the junction 119 prevents any further changes in the speed of the motor 123 when the bottom wall of the magazine 101 is driven at a proper speed. It will be noted that the metering device 102 of FIG. 1 is very similar tothe metering unit 7 of FIG. 3.

The admission of a certain quantity of comminuted tobacco stem and/or ribs is standard procedure in the manufacture of plain or filter tipped cigarettes and analogous rod-shaped smokers products.

The heating or drying unit 14 which occupies the treating station E of FIG. 1 is illustrated in FIG. 4. This unit is similar to that disclosed in Pat. No. 3,389,707. It comprises an inclined hollow rotary receptacle or drum 131 which is rotated about its axis by a drive 132 including a prime mover, a variable-speed transmission and a gear train comprising a pinion driven by the transmission and a ring gear on the drum 131. The intake end of the drum 131 receives a current of hot air from the outlet of a pipe 133g forming part of an adjustable hot air supplying device 133. The inlet of the pipe 133a contains an air heater 135, e.g., an electric resistance heater, and an intermediate portion of the pipe 133a contains a blower 136 which draws atmospheric air across the heater 135 and delivers the thus heated air current into the drum 131 so that the heated air current traverses the stream of a mixture of comminuted tobacco ribs or stem and shreds 27 supplied by a vibrating trough 144 forming part of a moisture detector 143.

The drum 131 is provided with internal blades or paddles 134 here shown as steam-heated coils 134 which extend lengthwise of the drum and serve to agitate the tobacco on its way from the moisture detector 143 toward the discharge end of the drum 131. The pipe 133a of the hot air supplying device 133 further comprises a flap valve 137 which is installed between the blower 136 and the air heater 135 and can admit varying amounts of unheated atmospheric air to thereby change the temperature of the air current which is being admitted into the drum 131. The position of the valve 137 (and hence the rate of admission of unheated atmospheric air into the pipe 133a) is adjustable by a servomotor 138 which receives signals from a signal comparing junction 141 by way of an output amplifier 139. The junction 141 receives signals from the conductor 88 (main set value potentiometer 86) by way of a time delay relay 142 and from a transducer 146 which forms part of the moisture detector 143. When the main set value potentiometer 86 is adjusted, the thus changed signal furnished by the conductor 88 is delayed by the relay 142 to an extent which is necessary to insure that the servomotor 138 adjusts the valve 137 at the exact time when the inlet of the drum 131 begins to receive tobacco at a different rate as selected by the main set value potentiometer 86. The moisture detector 143 is preferably of the type known as HWK produced by Hauni-Werke, Korber & Co., K.G., of I-lamburg-Bergedorf, Western Germany. The signals from the transducer 146 of the moisture detector 143 to the junction 141 are indicative of the moisture content of tobacco which is about to enter the drum 131. The valve 137 constitutes a means for adjusting the intensity of treatment of tobacco in the drum 131 in delayed response to signals which are generated on actuation of the main set value potentiometer 86.

The temperature of the blades 134 in the drum 131 can be regulated by a steam valve 147 which is installed in a steam supply conduit 147a; the latter is connected with the blades 134 by a distributor 147b mounted at the discharge end of the drum 131. The valve 147 is adjustable by a servomotor 148 which receives signals from a junction 151 by way of an output amplifier 149. The junction 151 receives signals from an adjustable potentiometer 152 or an analogous rated or set value selector and from a second moisture detector 153 installed upstream of the conveyor belt 4 and serving to measure the moisture content of successive increments of heated and dried tobacco which leaves the drum 131. The detector 153 is preferablysimilar to or identical with the detector 143. The setting of the potentiometer 152 determines the final moisture content of tobacco which leaves the drum 131, Le, the junction 151 causes the servomotor 148 to adjust the valve 147 when the signal from the potentiometer 152 deviates from the signal which is being furnished by the moisture detector 153.

The heating or drying unit 14 further comprises a pneumatic cooling device 154 which cools the tobacco issuing from the drum 131 and delivers cooled tobacco to the vibrating trough of the moisture detector 153. The cooling device 154 comprises a blower 154a which produces a current of gaseous coolant wherein the particles of tobacco travel as soon as they leave the drum 131. A further blower 147c is provided to evacuate spent gaseous fluid at the discharge end of the drum 131.

The heating unit 14 is necessary because the moisture content of tobacco leaves 19 must be increased well above the desired ultimate moisture content of tobacco (in the storing unit 17) before the tobacco leaves 19 enter the shredding machine 11a-11d. In the absence of such moisturizing, the shredding or an analogous comminuting treatment of tobacco would result in the generation of excessive quantities of dust. The ultimate moisture content of tabacco which is to be admitted into a cigarette making or other consuming machine must be maintained within a very narrow range. For example, if the tobacco which is being withdrawn from the storing unit 17 for delivery into a cigarette making machine would contain excessive amounts of moisture, the rod former of such machine would be rapidly clogged so that the machine would require extensive cleaning with attendant losses in output. It is within the purview of this invention to provide two or more treating stations at which the moisture content of tobacco is reduced stepwise rather than in a single operation.

The flavoring unit 16 occupies the treating station F and its details are shown in FlG. 5. The unit 16 comprises a hollow receptacle or drum 161 which is rotated by a drive 162 and the intake end of which receives a continuous stream of tobacco from the conveyor belt 4 by way of an intermediate conveyor belt 163. The interior of the drum 161 accommodates one or more stationary spray nozzles or atomizing nozzles 164 which are connected with a pump 167 by way of a conduit 166. The pump 167 is driven by a d-c motor 169 and draws casing and/or other flavoring agents from a tank or vessel 168. The signals for changing the speed of the motor 169 are furnished by a signal comparing junction 173 by way of a preamplifier 171 and an output amplifier 172. The junction 173 receives signals from a tachometer generator 176 which monitors the speed of the motor 169, from an adjustable rated or set value selector in the form of a potentiometer 177, and from the main set value potentiometer 86 by way of the conductor 88 and a time delay relay. 174. The latter delays a change in the speed of the pump motor 169 whenever the conductor 88 delivers a different signal so as to insure that the nozzle or nozzles 164 begin to discharge different quantities of easing as soon as the foremost part of the tobacco stream which is being furnished by the metering device 7 in response to change in the signal from the main set value potentiometer 86 reaches the interior of the drum 161. The operator can adjust l The conveyor belt-6 receives flavored tobacco from the drum 161 and introduces such tobacco into a container or box 182 through the intermediary of a further endless conveyor belt 181. The container 182 forms part of the tobacco storing unit 17 at the treating station G. The tobacco which is delivered by the intermediate conveyor 181 descends onto the upper stretch of an endless conveyor belt 183 which is driven by a d-c motor 187. Rotary rakes 184 are provided to evacuate tobacco from the floating store in the container 182 for delivery onto a take-off conveyor 186 which supplies tobacco toone or more consuming machines, e.g., to the magazine or magazines of one or more cigarette making machines, not shown.

The speed of the motor 187 is regulated by a signal comparing junction 189 by way of an output amplifier 188. The junction receives signals from a tachometer generator 193 which monitors he speed of the motor 187, from an adjustable rated or set value selector in the form of a potentiometer 192, and from the main set value potentiometer 86 by way of the conductor 88 and a time delay relay 191. The potentiometer 192 can be adjusted to change the rate of evacuation of tobacco from the container 182 independently of the setting of the main set value potentiometer 86. The relay 191 delays an altered signal from the main set value potentiometer 86 for an interval of time which suffices to insure that the foremost portion of the tobacco stream which is being fed at a different rate in response to an adjustment of the metering unit 7 by the main set value potentiometer 86 reaches the belt 183 in the container 182 when the belt 183 begins to move at a different speed.

The delay time can be as much as 500 seconds or even more, depending on the distance between the path section A and the stations D, E, F, G as well as on the speed of the

belts

3, 4, 6, 8. For example, there can be a time difference of 1-3 minutes if the nozzle or nozzles 164 are placed close to the intake or discharge end of the drum 161.

The purpose of the auxiliary set value potentiometer 177 is to enable an operator to rapidly change the quantity of easing and/or other flavoring agent which is being discharged by the nozzle or nozzles 164 per unit of time when the apparatus is converted from treatment of first type or types of tobacco to treatment of different second type or types of tobacco. It can happen that such conversion takes place several times in a single day. The main set value potentiometer 86 insures Thus, a temporary storage of tobacco in the container 182 brings about an equalization of moisture content of the entire floating store of tobacco. Another purpose of the storing unit 17 is to insure that the processing apparatus can meet the requirements of one or more consuming machines even if such requirements increase very rapidly, for example, in response to simultaneous starting of one or more consuming machines in addi-' tion to a single continuously operating consuming machine so that the throughput of tobacco in the path A must be multiplied or at least substantially increased within a very short period of time.

It will be noted that the auxiliary

set value potentiometers

107, 152, 177 and 192 allow for individual adjustments of the rate of tobacco transport or of the intensity of treatment at the stations D, E, F and G downstream of the path section A. Each such operation can be further directly influenced by an appropriate adjustment of the main set value potentiometer 86. ln other words, the person or persons in charge can arbitrarily adjust the ratio at which comminuted tobacco stem or ribs will be admixed to tobacco shreds 27 at the point 106, the ultimate moisture content of tobacco which stem to tobacco shreds 27 remains unchanged, the

moisture content of tobacco also remains unchanged and the intensity of flavoring treatment in the drum 161, too, remains unchanged. Thus, a change in the setting of the main set value potentiometer 86 merely changes the rate of withdrawal of tobacco from the storing unit 182. The primary function of the main set value potentiometer 86 is to allow for changes in the rate of withdrawal of conditioned tobacco from the storing unit 17 without changing the nature of the mixture which is formed at the point 106, the moisture content of tobacco and/or the flavoring action in the unit 16. The signals which are produced in response to an adjustment of the main set value potentiometer 86 are transmitted to the units at the stations D, E, F and G with an appropriate delay as described above, namely, to insure that the rate of delivery of comminuted ribs or stem to the point 106 increases or decreases proportionally with an increase or decrease in the rate of delivery of shredded tobacco 27 by the metering unit 7 and that the leading end of the increased or reduced stream of comminuted ribs or stem reaches the primary path A at the exact moment when the leading end of the altered stream of shreds 27 reaches the point 106; to further insure that the heating action of the blades 134 in the revolving drum 131 of the heating unit 14 is intensified or weakened at the exact moment when the drum 131 begins to receive a mixture of tobacco ribs or stem and shreds at a higher or lower rate; to insure that the nozzle or nozzles 164 in the revolving drum 161 will begin to discharge casing or flavoring at a different rate at the exact moment when the leading end of the altered tobacco stream moves into the range of such nozzle or nozzles; and to also insure that the withdrawal of tobacco from the container 182 is increased or reduced at the exact moment when the belt 183 begins to receive the leading end of the changed tobacco stream.

THE OPERATION The carded feeder belt 43 of the tobacco leaf feeding unit 12 draws destalked tobacco leaves 19 from the magazine 44 and delivers a stream of such leaves onto the upper stretch of the conveyor belt 1 which supplies tobacco leaves to the ducts 18a-18d of the four shredding machines 1 1a-l 1d of the comminuting unit 9. The tobacco leaves 19 which form the surplus 37 are recirculated into the magazine 44 by way of the belts 47-49 and the weighing device 38. The weighing device 38 cooperates with the set value potentiometer 36 and tachometer generator 46 to insure that the quantity and weight of tobacco leaves 19 per unit length of the stream which forms the surplus 37 remain at least substantially constant.

The output (namely, the weight of discharged shredded tobacco per unit of time) of the shredding machines 1 la] la! depends on the speed of the respective pairs of chains 21, 22 and also on the momentary crosssectional area of the passage defined by the corresponding mouthpieces 24. As a rule, the output of a shredding machine will fluctuate even if the duct 18 receives destalked tobacco leaves 19 at a constant rate. Consequently, the combined output of the shredding machines Ila-11d on the conveyor belt 2 downstream of the last shredding machine 11d will also fluctuate even if the combined tobacco leaf consumption of these machines is constant or nearly constant. This will explain the need for the metering device 7 which serves as a means for equalizing the stream of shreds 27 which are supplied by the conveyor belt 2 so as to insure a more uniform mixing and other treatment of shreds 27 downstream of the path section A. The weighing device 61 of the metering unit 7 receives from the hopper 63 a constant stream of tobacco shreds and delivers such stream to the conveyor belt 3 for transport toward the point 106. The rotational speed of the d-c motor 82 for the carded belt 62 of the hopper 63 and the endless band 83 of the weighing device 61 is a function of the product of signals indicating the angular position of the carrier or arm 77 and the momentary rotational speed of the motor 82 (tachometer generator 81). Such product is furnished by the signal multiplying circuit 79 which is connected with the potentiometer 78 and generator 81 and controls the rotational speed of the motor 82 by way of the junction 84 and output amplifier 87. The arrangement is such that the signal which is furnished by the multiplying circuit 79 is compared with the signal furnished by the main set value potentiometer 86. The rotational speed of the motor 82 does not change if the two signals neutralize each other but such speed will change if the intensity of the signal from the multiplying circuit 79 differs from that of the signal from the main set value potentiometer 86. The signal from the main set value potentiometer 86 controls; i.e., the motor 82 will ultimately rotate at the speed as selected by the setting of the potentiometer 86.

Due to the reasons which were explained above, the combined output of the shredding machines 11a-11d per unit of time does not exactly correspond to the amount of tobacco which is being withdrawn from the supply 64 per same unit of time. Thus, the quantity of tobacco shreds 27 in the supply 64 fluctuates and the purpose of the detector 66 and control circuit 28 is to prevent excessive deviations of the combined output of shredding machines Ila-11a from the requirements of the belt 3 as determined by the setting of the main set value potentiometer 86. The cells 67-69 of the detector 66 produce signals in the aforedescribed manner, and the circuit 71 transmits such signals to the input c of the junction 31 by way of the conductor 30 to thereby influence the output of the shredding machine 11d in a manner to increase such output if the signal is furnished by the cell 69 and to decrease the output of the shredding machine 11d when the signal is furnished by the cell 67. The output of the shredding machine 11d is changed in response to changes in the speed of the d-c motor 23d which drives the

chains

21d, 22d. if the quantity of tobacco shreds 27 in the supply 64 rises,

the input c of the junction 31 receives a weaker signal to thus indicate that the output of the shredding machine 11d should be reduced. As the output of the machine 11d decreases, the quantity of tobacco shreds 27 in the supply 64 also decreases and the input c of the junction 31 receives a stronger signal from the cell 69 (by way of the circuit 71 and conductor when the level of tobacco shreds in the supply 64 decreases to the lowermost permissible level. The output of the shredding machine 11d is then increased so that the level of shreds in the hopper 63 begins to rise toward the uppermost cell 67 of the detector 66. Thus, the detector 66 insures that the hopper 62 invariably contains a sufficientquantity of tobacco shreds 27 to meet the requirements of the conveyor 3 in dependency on the setting of the main set value potentiometer 86.

' The constant stream of tobacco shreds 27 which is being transported by the conveyor belt 3 downstream of the path section A is mixed (at 106).with the stream of comminuted ribs or stem furnished by the conveyor belt 8. The stem or ribs are also furnished in the form of a constant stream because the operation of the feeding unit 13 is dependent on the setting of the main set value potentiometer 86 in a manner and for the reasons as described in connection with FIG. 1. Thus, the

weighing device 113 receives from the carded belt 111 a constant stream of comminuted tobacco stem or ribs and, if the quantity of stem or ribs in a unit length of such stream deviates from the desired quantity, the potentiometer 114 transmits a corresponding signal to the multiplying circuit 116 which influences the speed of the motor 109 by way of the junction 103 and output amplifier 108 The signal from the multiplying circuit 116 to the junction 103 is indivative of the actual rate that the supply of comminuted stem or ribs in the hopper 112 always remains within a desired range; to this end, the signal from the detector 1 18 changes the speed of the motor 123 for delivery of tobacco stem or ribs from the magazine 101 to the hopper 112 if the quantity of stem or ribs in the hopper 112 increases above or decreases below a predetermined maximum or minimum quantity. The construction and mode of opera tion of the detector 118 may be similar to those of the detector 66 in the hopper 63 of the metering unit 7.

The tobacco stream which contains a mixture of comminuted stem or ribs and tobacco shreds 27 is transported by the conveyor belt 3 beyond the point 106 and is admitted into the drum 131 of the heating or drying unit 14. The detector 143 determines the moisture content of successive increments of the tobacco stream prior to entry into the drum 131, and the signals from the detector 143 are used to adjust (when necessary) the valve 137 and to thus determine the temperature of the hot air current which is caused to flow across the tobacco stream at the inlet of the drum 131., A signal from the transducer 146 of the moisture detector 143 will result in an adjustment of the valve 137 if the intensity of such signal deviates from that which is being furnished to the junction 141 by the main set value potentiometer 86 (through the intermediary of the conductor 88 and time delay relay 142). if the moisture content of tobacco which is being admitted into the vibrating trough 144 of the detector 143 is relatively high, the servomotor 138 will be caused to move the flap of the valve 137 toward its closed position so that the valve 137 admits into the pipe 13311 a reduced amount of unheated atmospheric air whereby the temperature of the air current which is being discharged by the pipe 133a increases. This insures a more intensive drying of tobacco in the drum 131. The final moisture content ot' tobacco which leaves the drum 131 can be regulated with a high degree of precision by changing the position of the valve 147 which admits steam into the blades 134 of the drum 131. The position of the valve 147 will be adjusted if the moisture content of tobacco which has passed through the pneumatic cooling device 154 and reaches the vibrating trough of the detector 153 deviates from the desired moisture content as selected by the auxiliary setvalue potentiometer 152. Thus, if the signal which is being furnished by the detector 153 deviates from the signal which the junction 151 receives from the potentiometer 152, the moisture content of tobacco in the trough of the detector 153 is unsatisfactory and the heating action of blades 134 in the drum 131 is changed by increasing or reducing the rate of circulation of steam therethrough.

The conveyor belts 4 and 163 deliver a continuous stream of properly cooled and dried tobacco into the drum 161 of the flavoring unit 16. The nozzle or nozzles 164 discharge into the agitated tobacco stream in the drum 161 a predetermined quantity of casing and- /or other flavoring agent or agents per unit of time, and such casing is furnished by the pump 167 which draws the liquid from the vessel 168 and conveys it to the nozzle or nozzles 164 by way of the conduit 166. The rate of admission of casing to the nozzle or nozzles 164 will be changed if the operator decidesto adjust the main set value potentiometer 86 and/or the auxiliary set value potentiometer 177. The adjustment of the auxiliary potentiometer 177 results in an immediate change of the rate of admission of casing; the adjustment of the main set value potentiometer 86 influences the speed of the pump motor 169 with a delay which is determined by the relay 174 in the conductor 88. The tachometer generator 176 delivers to the junction 173 signals which are indicative of the momentary rate of admission of casing into the drum 161 (such rate is proportional to the speed of the motor 169). The drum 161 is preferably provided with internal blades or paddles which agitate the tobacco stream to insure a more uniform distribution of atomized casing to all particles of the tobacco stream.

The conveyor belts 6 and 181 deliver a continuous stream of tobacco from the drum 161 into the container 182 of the storing unit 17 at the treating station G. Successive increments of the tobacco stream descend onto the upper stretch of the belt 183 which is driven by the motor 187. The quantity of tobacco which is being withdrawn from the container 182 per unit of time depends on the thickness of the tobacco layer on the belt 183 and on the speed of the motor 187. Thus, the quantity of withdrawn tobacco can be changed by changing the speed of the motor 187 in response to signals from the main set value potentiometer 86 (conductor 88) or from the auxiliary set value potentiometer 192. The tachometer generator 193 furnished to the junction 189 signals which are indicative of the momentary speed of the motor 187 and hence of the momentary rate of withdrawal of tobacco from the container 182. Since the thickness of the tobacco layer onthe belt 183 is normally constant, the rate of withdrawal of tobacco from the container 182 normally depends exclusively on the speed of the motor 187.

An important advantage of the apparatus of FIGS. 1 to is that the condition of tobacco which leaves the container 182 of the storing unit 17 at the treating station G does not change if the operator decides to change the rate of withdrawal of tobacco shreds 27 from the hopper 63 of the metering unit 7 by changing the setting of the main set value potentiometer 86. Each such adjustment of the potentiometer 86 directly influences the operation of the

units

13, 14, 16, 17 at the stations D, E, F and G and indirectly influences the operation of the units 9, 12 at the stations B and C. The time delay relays 104, 142, 174 and 191 (or other suitable time delay devices) insure that the adjustments of the main set value potentiometer 86 become effective only at such times when the leading end of the altered stream of tobacco shreds 27 reaches the point 106 and also when the leading end of the altered stream consisting of a mixture of tobacco shreds 27 and comminuted stem or ribs reaches the treating stations E, F and G. The adjustments of the main set value potentiometer 86 are communicated to the units 9 and 12 indirectly by way of the detector 66 which responds to changes in the quantity of tobacco shreds 27 on the hopper 63 and thereby influences the output of the shredding machine lld which, in turn, influences the output of the feeding unit 12. The improved apparatus renders it possible to change the rate of delivery of tobacco to one or more consuming machines by the simple expedient of adjusting the main set value potentiometer 86 so that the entire apparatus can be supervised by a single person. All such a person has to do is to check the requirements of the consuming machine or machines and to adjust the main set value potentiometer 86 if and when necessary. The

auxiliary potentiometer

36, 107, 121, 152, 177 and/or 192 will be adjusted only if the operator decides to change the mode of operation of a particular unit independently of the setting of the main set value potentiometer 86. The automatic transmission of signals in response to adjustments of the main set value potentiometer 86 is much more reliable than individual adjustments of discrete units whenever it becomes necessary to change the rate of tobacco withdrawal from the storing unit 17 at the station G without changing the nature of treatment of tobacco at the preceding stations.

The apparatus of FIG. 6 is similar to the apparatus of FlGS. 1-5 and, therefore, all such component parts of this apparatus which are identical with or clearly analogous to the corresponding parts of the first apparatus are denoted by similar reference characters plus 200. The main difference between the two apparatus is that the

potentiometers

308, 398, 396, 321, 286, 236, 352, 377 and 392 of FIG. 6 are accommodated in a single central control housing 396 which is readily accessible so that an operator need not search for discrete potentiometers but can carry out each and every adjustment after gaining access to the interior of the housing 396.

The potentiometer 236 supplies signals to the junction 239 of the regulating circuit 234 for the stripped or destalked tobacco leaf feeding unit 212; the main potentiometer 286 is directly connected with the junction 284 and indirectly with the junctions 341, 373, 398 (through the intermediary of

time delay devices

342, 374, 391; the potentiometer 321 is connected with the junction 319; a second main set value potentiometer 398 is connected with the junction 303 by way of the potentiometer 307; the potentiometer 352 is connected with the junction 351; the potentiometer 377 is connected with the junction 373; and the potentiometer 392 is connected with the junction 389.

The operation of the apparatus of FIG. 6 is analogous to that of the first apparatus. As mentioned above, the main difference between the two apparatus is that all of the potentiometers are accessible in the housing 396 to thus save time for carrying out a change in the setup, either by way of the main

set value potentiometers

286 and 398 or by way of auxiliary potentiometers which serve as rated or set value selectors for discrete units.

Since the metering unit 7 is installed in the intermediate path section A, it can insure that the throughput of tobacco at the stations E, F and G (as well as along the point 106) remains constant as long as the setting of the potentiometer 86 remains unchanged. Thus, a single metering unit suffices to insure that the treating units l4, l6 and 17 at the stations E, F and G receive tobacco at a constant rate. This brings about substantial savings in space as well as in initial and maintenance cost because the presently known apparatus still employ discrete metering means upstream of each such station where the treatment of tobacco can be adversely affected by fluctuations in the rate of tobacco throughput. This applies particularly for the stations E and F as well as for the blending action at the point 106 where the stream of shreds 27 is being mixed with the stream of a second type of tobacco.

If the processing apparatus comprises several treating units whose output is likely to fluctuate, i.e., if the comminuting unit 9 is preceded or followed by one or more treating units whose output of tobacco is not predictable with a reasonable degree of accuracy, the hopper 63 is preferably placed downstream of the last treating unit with fluctuating output. This insures that the supply 64 of tobacco in the hopper 63 forms a reserve which can be temporarily increased or reduced in response to adjustments of the metering unit 7 by the potentiometer 86 but is invariably sufficient to meet the momentary requirements of the treating units at the stations D, E, F and G. The cells 67 and 69 of the detector 66 insure that the quantity of tobacco shreds 27 in the supply 64 invariably remains within a predetermined range so that the path portion downstream of the section A receives enough tobacco even if the potentiometer 86 is actuated to abruptly increase the rate of tobacco transport through the stations E, F and G from a minimum to a maximum value.

The feeding unit 12 is desirable because it insures that the feeder belt 43 withdraws from the magazine or source 44 toabacco leaves 19 at a rate which exceeds the requirements of the comminuting unit 9 so that the surplus 37 forms a fluctuating stream which is being recirculated by the conveyors 47-49. The weighing device 38 insures that the rate at which the feeder belt 43 delivers tobacco leaves 19 from the magazine 44 to the conveyor belt 1 of the transporting system increases if the requirements of the shredding machine 110! are increased in response to a signal from the detector 66. This, in turn, insures that the rate of admission of tobacco leaves 19 into the duct 18d of the shredding machine l ld can be increased without any delay as soon as the cell 69 of the detector 66 produces a signal which indicates that the supply 64 of shreds 27 has been depleted to a predetermined minimum value. In the absence of the feeding unit 12, and particularly in the absence of means'for establishing and maintaining the stream 37 of surplus leaves, it would take longer to increase the output of the shredding machine llld in response to a signal from the detector 66.

FIG. 7 illustrates a portion of a third apparatus. All such parts of this apparatus which are identical with or clearly analogous to the corresponding parts of the apparatus shown in FIGS. 1-3 are denoted by similar reference characters plus 400. The main difference between this apparatus and the apparatus of FIGS. 1 to is that the main set value potentiometer 486 is directly connected with the junction 431 of the control circuit 428 for the shredding machine 411d in the comminuting unit 409 at the treating station B. Thus, the junction 431 receivessignals from the main set value potentiometer 486 as well as from the photoelectric'detector or monitoring means 466 in the hopper 463 of the metering unit 407. Consequently, the main set value potentiometer 486 directly influences the operation of units at the treating stations (not shown) which are located downstream of the path section A as well as the operation of units 409., 412 at the treating stations B and C which are located upstream of the path section A.

For example, if the operator decides to adjust the main set value potentiometer 486 so as to increase the rate of withdrawal of tobacco shreds from the hopper 463, the nature of treatment of tobacco at the stations E, F and G (not shown in FIG. 7) remains unchanged but the rib or stem feeding unit delivers to the primary path A comminuted stem or ribs at a correspondingly increased rate. The signal which is produced on adjustment of the main set value potentiometer 486 is transmitted directly to the junction 431 so that the output of the shredding machine 411d increases immediately, i.e., such adjustment of the output of the shredding machine 411d need not await a change in the level of the supply of tobacco shreds in the hopper 463. Of course,

the indirect adjustment by way of the photosensitive detector 466 preferably remains since such adjustment might be necessary in the event that the rate of delivery of tobacco shreds into the hopper 463 varies as a result of improper operation or stoppage of at least one of the shredding machines 41 la, 41 lb, 4110.

It is further clear that the improved method and apparatus can be modified in a number of ways without departing from the spirit of the invention. For example, the number of treating units downstream of the path section A can be reduced to one, two or three, or increased beyond four. The heating unit 14 can be combined with, preceded or followed by a unit which changesthe volume of tobacco particles by vaporizing the moisture in the capillaries of such particles and by thereupon rapidly drying the particles. Also, the sequence of various treating units can be altered and each type of tobacco can be subjected to a'series of treatments prior to blending. The term processing as utilized herein is intended to embrace all treatments which can change the physical and/or mechanical characteristics of tobacco, such' aschanges in size, shape,

volume, temperature, moisture content and/or aroma, as well as blending of two or more tobacco types or sizes. The changes in moisture content may include a reduction of or an increase in moisture content.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. A method of processing tobacco, comprising the steps of transporting at least one stream of tobacco along an elongated path past a plurality of treating stations including at least one first station located upstream and at least one second station located downstream of a predetermined section of said path; subjecting the tobacco'stream at said section to a variable equalizing action so that each unit length of the tobacco stream downstream of said section normally contains identical quantities of tobacco; adjusting the treatment of tobacco at said second station in response to variations of said equalizing action; monitoring the rate of tobacco transported between said section and said first station; and adjusting the treatment of tobacco at said first station as a function of variations of such rate of tobacco transport.

2. A method as defined in claim 1, wherein the adjustment of treatment of tobacco at said second station takes place in direct response to variations of said equalizing action, and further comprising the step of delaying such adjustment until the leading end of the tobacco stream which leaves said section subsequent to a variation of said equalizing action reaches said second station.

3. A method as defined in claim 1, further comprising the step of adjusting the treatment of tobacco at said first station in direct response to variations of said equalizing action.

4. A method as defined in claim 1, further comprising the step of building up at said section a supply of tobacco arriving from said first station, said step of subjecting the tobacco stream to said variable equalizing action comprising withdrawing tobacco from said supply at a selected one of a plurality of different rates.

5. A method as defined in claim 4, wherein said monitoring step comprises scanning said supply and said step of adjusting the treatmen t of tobacco at said first station comprises changing the output of treated tobacco at said first station when the quantity of tobacco in said supply is without a predetermined range.

6. A method as defined in claim 1, wherein the treatment of tobacco at said first station includes comminuting tobacco at a variable rate and said step of adjusting the treatment of tobacco at said first station comprises changing the quantity of comminuted tobacco leaving said first station.

7. A method as defined in claim 6, further comprising the steps of feeding to said first station tobacco at a rate exceeding the tobacco requirements of said first station so as to establish a fluctuating surplus of tobacco which is not comminuted at said first station, measuring the quantity of tobacco forming said surplus, and changing the rate of feed of tobacco to said first station in dependency on the fluctuations of said surplus.

8. A method as defined in-claim 1, wherein the treatment of tobacco at said second station comprises admixing to said tobacco stream at least one second type of tobacco at a rate which varies proportionally with variations of said equalizing action.

9. A method as defined in claim 1, wherein the treatment of tobacco at said second station comprises changing the moisture content of tobacco.

10. A method as defined in claim 1, wherein the treatment of tobacco at said second station comprises storing the tobacco of said stream to form a floating store of tobacco and withdrawing tobacco from such floating store at a rate which varies proportionally with variations of said equalizing action.

11. A method as defined in claim 1, wherein the treatment of tobacco at said second station comprises contacting successive increments of said tobacco stream with at least one flavoring agent at a rate which varies proportionally with the variations of said equalizing action.

i2. A method as defined in claim 1, further comprising the step of adjusting the treatment of tobacco at least at one of said stations independently of said variations.

13. A method as defined in claim 12, further comprising the step of placing the instrumentalities for carrying out adjustments of said equalizing action into close proximity of instrumentalities for carrying out independent adjustments of tobacco treatment at said one station.

14. ln an apparatus for processing tobacco, a combination comprising transporting means defining an elongated path wherein tobacco is conveyed in the form of a stream, said path including an intermediate section; at least one first adjustable tobacco treating unit adjacent to said path upstream of said section; at least one second adjustable tobacco treating unit adjacent to said path downstream of said section; an adjustable equalizing unit provided at said section and arranged to subject the tobacco of said stream to a variable equalizing action so that each unit length of the tobacco stream downstream of said section normally'contains a fixed quantity of tobacco; detector means adjacent to said path between said first unit and said equalizing unit for producing first signals indicative of the rate of tobacco transport to said equalizing unit; control means for adjusting said first unit in response to said first signals so as to maintain said rate within a predetermined range, main set value selector means actuatable to generate second signals; first adjusting means for adjusting said equalizing unit in response to said second signals to thereby change the quantity of tobacco per unit length of the tobacco stream downstream of said section; and second adjusting means for adjusting said second unit in response to said second signals.

15. A combination as defined in claim 14, further comprising time delay means interposed between said main set value selector means and said second adjusting means for delaying the transmission of said second signals so that the adjustment of said second unit takes place substantially simultaneously with arrival of the foremost changed quantity of tobacco per unit length of said stream into the range of said second treating unit. i

16. A combination as defined in claim 14, wherein said control means is responsive to said second signals so that said first unit is adjusted in response to either of or both said first and second signals.

17. A combination as defined in claim 14, wherein said equalizing unit comprises means for accumulating a supply of tobacco which is being transported to said section and means for withdrawing from said supply tobacco for transport toward said second unit.

l8. A combination as defined in claim 17, wherein said detector means comprises means for monitoring the quantity of tobacco in said supply.

19. A combination as defined in claim 14, wherein said first unit comprises at least one tobacco shredding machine whose output of shredded tobacco is adjustable in response to said first signals. 7

20. A combination as defined in claim 19, further comprising a source of tobacco leaves and feeder means for delivering a stream of tobacco leaves from said source to said transporting means for introduction into said shredding machine.

21. A combination as defined in claim 20, wherein said feeder means is arranged to deliver to said transporting means tobacco leaves in quantities correspond ing to the requirements of said shredding machine plus a surplus of tobacco leaves, and further comprising recirculating conveyor means for returning said surplus to said source in the form of a stream, signal generating weighing means for monitoring the quantity of tobacco leaves per unit length of said surplus stream, and regulating means for controlling the rate of withdrawal of tobacco leaves from said source by said feeder means in response to signals from said weighing means.

22. A combination as defined in claim 14, wherein said second treating unit comprises a source of a tobacco type other than tobacco which is being transported to said metering unit, an adjustable equalizing device arranged to withdraw from said source tobacco of said other type for delivery to said path downstream of said section, and adjusting means for adjusting said equalizing device in response to said second signals.

23. A combination as defined in claim 14, wherein said second treating unit comprises means for changing the moisture content of tobacco.

24. A combination as defined in claim 14, wherein said second treating unit comprises means for storing the tobacco supplied thereto by said transporting means.

25. A combination as defined in claim 14, further comprising auxiliary set value selector means actuatable to adjust at least one of said treating units independently of said main set value selector means.

26. A combination as defined in claim 25, wherei said main set value selector means and said auxiliaryset value selector means are closely adjacent to each other.

27. A combination as defined in claim 14, wherein said second treating unit comprises means for inti mately contacting the tobacco of said stream with at unit is the same prior and subsequent to generation of v a second signal.

29. A combination as defined in claim 14, wherein said metering unit comprises a tobacco weighing device.

Claims

1. A method of processing tobacco, comprising the steps of transporting at least one stream of tobacco along an elongated path past a plurality of treating stations including at least one first station located upstream and at least one second station located downstream of a predetermined section of said path; subjecting the tobacco stream at said section to a variable equalizing action so that each unit length of the tobacco stream downstream of said section normally contains identical quantities of tobacco; adjusting the treatment of tobacco at said second station in response to variations of said equalizing action; monitoring the rate of tobacco transported between said section and said first station; and adjusting the treatment of tobacco at said first station as a function of variations of such rate of tobacco transport.

5. A method as defined in claim 4, wherein said monitoring step comprises scanning said supply and said step of adjusting the treatment of tobacco at said first station comprises changing the output of treated tobacco at said first station when the quantity of tobacco in said supply is without a predetermined range.

8. A method as defined in claim 1, wherein the treatment of tobacco at said second station comprises admixing to said tobacco stream at least one second type of tobacco at a rate which varies proportionally with variations of said equalizing action.

12. A method as defined in claim 1, further comprising the step of adjusting the treatment of tobacco at least at one of said stations independently of said variations.

14. In an apparatus for processing tobacco, a combination comprising transporting means defining an elongated path wherein tobacco is conveyed in the form of a stream, said path including an intermediate section; at least one first adjustable tobacco treating unit adjacent to said path upstream of said section; at least one second adjustable tobacco treating unit adjacent to said path downstream of said section; an adjustable equalizing unit provided at said section and arranged to subject the tobacco of said stream to a variable equalizing action so that each unit length of the tobacco stream downstream of said section normally contains a fixed quantity of tobacco; detector means adjacent to said path between said first unit and said equalizing unit for producing first signals indicative of the rate of tobacco transport to said equalizing unit; control means for adjustIng said first unit in response to said first signals so as to maintain said rate within a predetermined range; main set value selector means actuatable to generate second signals; first adjusting means for adjusting said equalizing unit in response to said second signals to thereby change the quantity of tobacco per unit length of the tobacco stream downstream of said section; and second adjusting means for adjusting said second unit in response to said second signals.

15. A combination as defined in claim 14, further comprising time delay means interposed between said main set value selector means and said second adjusting means for delaying the transmission of said second signals so that the adjustment of said second unit takes place substantially simultaneously with arrival of the foremost changed quantity of tobacco per unit length of said stream into the range of said second treating unit.

18. A combination as defined in claim 17, wherein said detector means comprises means for monitoring the quantity of tobacco in said supply.

19. A combination as defined in claim 14, wherein said first unit comprises at least one tobacco shredding machine whose output of shredded tobacco is adjustable in response to said first signals.

21. A combination as defined in claim 20, wherein said feeder means is arranged to deliver to said transporting means tobacco leaves in quantities corresponding to the requirements of said shredding machine plus a surplus of tobacco leaves, and further comprising recirculating conveyor means for returning said surplus to said source in the form of a stream, signal generating weighing means for monitoring the quantity of tobacco leaves per unit length of said surplus stream, and regulating means for controlling the rate of withdrawal of tobacco leaves from said source by said feeder means in response to signals from said weighing means.

26. A combination as defined in claim 25, wherein said main set value selector means and said auxiliary set value selector means are closely adjacent to each other.

27. A combination as defined in claim 14, wherein said second treating unit comprises means for intimately contacting the tobacco of said stream with at least one liquid agent.

28. A combination as defined in claim 14, wherein said second adjusting means is arranged to adjust said secOnd treating unit with a delay required for transport of the foremost changed quantity of tobacco into the range of said second unit and to the extent required to insure that the condition of tobacco leaving said second unit is the same prior and subsequent to generation of a second signal.