Patent Publication Number: US-4058129-A

Title: Continuous process for the production of a paste with additives which can be formed into a smokable material

Description:
BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-sectional view of a stirrer crushing mill for the practice of the novel process, 
     FIG. 2 is a view as seen in the direction of arrow II in FIG. 1, and 
     FIG. 3 shown a powder allotter for the stirrer crushing mill of FIG. 1. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     The stirrer crushing mill 22 comprises according to FIG. 1 a circular cylindrical casing 40 which has a horizontal axis 41 and is mounted on a small plate 42. The jacket of the casing 40 is double walled (the outer wall is marked 43 and the inner wall 44) so that it defines an annular cavity 45 which is connected to a cooler 50 by an inlet nozzle 46 and an outlet nozzle 47 and during operation, as far as necessary, is suffused with cooling water. The grinding chamber 49 is surrounded by the inner wall 44 and extends lengthwise in the direction of the axis 41 and crosswise so that it has a circular cross-section and tapers in the direction shown by arrow 48. The left-hand end of the grinding chamber 49 is closed by a removable cover 54. The grinding chamber 49 is equipped with a grinding tool 10, the shaft 51 of which extends coaxially to the casing 40, is journalled in the cover 54 and in the opposite end wall 56, extends from grinding chamber 49 through a pressure-tight and liquid-tight passageway 55 and is driven in the direction of arrow 11 (FIG. 2) by an electric motor 96. 
     Six grinding discs 52, 53 . . . are affixed to the grinding shaft 51 and consist of a rubbery elastic material such as plastic. The shaft 51 extends through a sieve plate 57 which separates an antechamber 12 from the grinding chamber 49. The outlet 58 for the paste communicates with this antechamber 12. The grinding chamber 49 is filled with grist 97, 98. The inlet end of the casing 40 is marked 16 and the exit end 17. 
     Four supply conduits convey constituents of paste into the grinding chamber 49. These include a supply conduit 13 for the liquid, a supply conduit 14 for the pulverized plant parts and supply conduits 15 and 18 for the particles of grist. The supply conduits are mounted close to the edge of the cover 54; with respect to the axis 41 they are mounted at the same distance from the inlet end 16 in an area 29. With respect to the direction of rotation of the grinding tool 10 according to arrow 11 and therefore also with respect to the direction of movement of the grist particles 97, 98, as shown by arrow 99, they are mounted in the sequence depicted in FIG. 2, whereby the supply conduit 13 for the liquid is situated first followed in the direction of rotation by the supply conduit 14 for plant powder which is followed by the supply conduits 15, 18 for the particles of grist. The discharge ends of the conduits follow each other closely in the circumferential direction so that the liquid introduced via conduit 13 is carried off by the grist in the joint area of the supply conduits 14, 15 and 18. 
     The supply conduit 13 is connected to a liquid source or tank 74 with the interposition of a pressure pump 19, the supply conduit 14 is attached to the pulverized plant source 76 with the interposition of an allotter or metering means 75, the supply conduit 15 is connected to a first source 77 of grist with the interposition of a grist allotter 24 and the supply conduit 18 is attached to a second source 25 of grist with the interposition of a grist allotter 23. 
     A capacity indicator continually measures the output capacity of the motor 96 and depending upon the measurement results, controls the grist allotters 23 and 24 with the interposition of a regulating instrument 79. The proportion of the necessary grist replenishment through the grist allotters 23 and 24 can be set by a device 28 on the regulating instrument 79. With the one extreme setting of the device 28 the entire grist replenishment from the source 77 occurs through the grist allotter 24 and with the other extreme setting the replenishment correspondingly is provided exclusively by the source 25. Using intermediate settings on the device, a mixed grist replenishment from both grist sources 77 and 25 is achieved, whereby the admixture rate can be set at any chosen proportion by the device 28. The total amount of the grist replenishment is not dependent on the setting of the device 28 and is solely dependent on the capacity measured by the capacity indicator 27. 
     A viscosity gauge 26 is attached to the outlet 58 and measures the viscosity of the outflowing paste and depending upon the measurement results regulates the pressure pump 19 with the interposition of a regulating instrument 78. A device 102 by means of which the distribution rate with which the plant powder is pressed into the grinding chamber 49 can be regulated is provided for the plant powder allotter 75. This distribution rate can be read off the indicator 100. The distribution rate with which the grist from the grist allotter 23 is pressed into the grinding chamber 49 can be read off the indicator 101. 
     During operation, the grinding chamber 49 is filled approximately 90 percent with grist having a diameter of between 3 and 5 mm and which only after having been ground down to a diameter of 0.3 mm can pass through the sieve plate 57 with the paste. The grist packing is saturated with water. The liquid tank 74 is filled with water; the plant powder source 76 contains about 50 to 100 μ finely ground dry plant powder. The grist source 77 contains glass beads with a diameter of 3 mm and the grist source 25 contains flint pebbles with a diameter of between 3 and 5 mm. The grindings of these flint pebbles are well suited as an adsorption material whereas the grindings of the glass beads are not. The grist packing in the grinding chamber 49 consists of one-third glass beads and two-thirds flint pebbles. The admixture rate is set at the proportion of 1 to 2 on the device 28 so that to one part glass beads always two parts of flint pebbles are added. The device 102 is to be set at a level based on experimentation. Now the stirrer crushing mill can be put into operation. The grinding tool 10 is now to be set in rotation and the liquid, pulverized plant parts and grist replenishment are to be pressed into the supply conduits 13, 14, 15 and 18 by the distributors 18, 75, 23 and 24 in the quantity to be set on each distributor. The liquid, together with the plant powder, passes through the grinding chamber 49 in the direction of arrow 48 -- the movement direction -- and is ground and blended in the process into a homogeneous paste and together with the grist grindings which have collected in the meantime leaves the grinding chamber 49 through the sieve 57 and flows out by way of the outlet 58 as a finished paste. If the paste contains too much liquid, the viscosity gauge 26 reduces the liquid supply at the pressure pump 19 and if the necessary capacity of the stirrer is too low, the capacity indicator 27 increases the amount of grist replenishment at the grist allotters 23 and 24. 
     When an equilibrium has been reached in the process, then the amount of plant parts and grindings from flint pebbles which flow out of the outlet in the paste during a time unit is the same as the amount shown on the indicators 100 and 101. If this proportion of grindings of flint pebbles to the plant parts in the finished paste is not at the desired level, a different mixture rate can be set by the device 28. If the amount of grindings of flint pebbles is too small, more flint pebbles and fewer glass beads are to be introduced and vice versa. 
     The mill can be operated exclusively with glass beads or with flint pebbles by regulating the device 28 accordingly. If the grinding is always to be done with only one type of grist, then one of the two grist allotters, together with its grist supply and supply nozzle as well as device 28, can be omitted. 
     The chemicals and other additives to be introduced into the paste to be formed are mixed into the paste leaving the outlet 58. The paste is then spread out into a foil and stabilized through the process of drying. Instead of this, it is also possible to dissolve the chemicals and additives, if they are soluble, in the liquid contained in the liquid tank 74, and if they are insoluble to admit them in a pulverized state into the plant powder source 76 or to levigate them into the liquid in the liquid tank 74. 
     Pump 19 is a pressure pump which pumps the liquid into the grinding chamber 49 at a pressure of 6 bar (atmospheric pressure). The liquid pressure inside the grinding chamber is in the range of 3 bar. The details of the powder distributor 75 and its supply conduit 14 are shown in FIG. 3. 
     The opening 80 of the supply nozzle 14 is provided in the inner wall 44 and a feed screw 84 mounted within the supply nozzle 14 ends at this opening. Mounted on the supply nozzle 14 is a funnel 82 which is the lower part of the container for the pulverized plant source 76. The shaft 83 of the screw 84 is connected to a motor 85, extending upwards out of the container for the pulverized plant source. The motor 85 therefore constitutes together with the screw 84 the distributor 75 and its speed can be set by the device 102. 
     The allotters 23 and 24 for the grist together with their supply conduits 15 and 18 are constructed virtually exactly in the same way as the allotter and the supply conduit depicted in FIG. 3. However, it is advisable to coat the edges of the screw adjacent the supply conduit with hard rubber in order to avoid unnecessary friction of the grist at that point. 
     As shown by the dotted line in FIG. 2 a departure from the depicted operational example may be made by mounting an additional supply conduit 20 for liquid between the supply conduits 14 and 15, which is also fed by the pump 19 from the liquid tank 74 with a portion of the liquid to be introduced. In this manner the grist replenishment entering the chamber by way of the supply conduits 15 will be thoroughly moistened right from the start. Analogously, one can also provide an additional supply conduit for liquid in front of the supply conduit 18. 
     In an instance where the grinding procedure is to be carried out without using grist, the supply conduits 15 and 18 can be shut off or omitted together with the grist allotters 23 and 24 and the grist sources 25 and 77. In such a case during operation only the grinding stock consisting of plant parts and liquid which completely fills the grinding chamber 49 is to be found in the grinding chamber 49. The procedure is the same as with the use of grist except that the grinding stock can be drier than if grist is used; for one part by weight of dry substance 2 to 3 parts by weight of water suffice; the grinding tool 10 can be driven at a lower speed when using grist. 
     EXAMPLES 
     EXAMPLE 1 
     For the production of regenerated tobacco, dry pulverized tobacco discards of a size between 50 and 100 μ, as is to be found in cigarette production, are introduced into the pulverized plant source 76. For every 10 kilograms of pulverized tobacco discards which enter the grinding chamber 49, 50 liters of water from the liquid tank 74 are introduced into the grinding chamber 49. Serving as grist, flint pebbles are continually introduced into the grinding chamber 49 by allotter 23 and glass beads with a diameter of 3 mm by allotter 24 in such an amount that the paste containing 50 liters of water for every 10 kilograms of tobacco discards which flows out of the outlet nozzle 58 consists of 700 grams of shavings from flint pebbles with a grain size of between 50 and 300μ and 50 grams of shavings from glass beads with a grain size of between 100 and 300 μ. For every 10 kilograms of tobacco refuse, 200 grams calcium nitrate, 500 grams carboxy methyl cellulose and 800 grams glycerin are mixed into the paste. The paste is then spread out and stabilized into a foil through the process of drying. 
     EXAMPLE 2 
     It is the same as example 1 with the sole difference that no grist is introduced into the stock and that for every 10 kilograms of pulverized tobacco discards 30 liters of water instead of 50 liters are introduced into the grinding chamber 49 from the liquid tank 74.