Patent Publication Number: US-6712496-B2

Title: Auger fed mixer apparatus and method of using

Description:
FIELD OF THE INVENTION 
     This invention relates to apparatus, which handle solids, and more particularly to such apparatus useful for dispersing solids into liquids. 
     BACKGROUND OF THE INVENTION 
     Mixers are well known in the art. Mixers have been used to mix solids with other solids and solids with liquids. Solids, as used herein, refers to particulate materials having a median particle size ranging from about 1 micron to about 2 centimeters. Typically solids used with the present invention will have a median particle size ranging from about 20 to 500 microns. Median particle size is measured according to ASTM Standard E1638, incorporated herein by reference. Liquids refers to incompressible materials having no shear modulus. It is to be understood that a mixer may have one or more solids and one or more liquids. The invention described and claimed herein is equally well suited for single and plural solid and/or liquid combinations. 
     The solids are typically introduced to the mixer through a series of stages in an apparatus. The mixer may be one stage at an intermediate position in or near the end of the apparatus. The first stage of the apparatus is typically a hopper. Solids are introduced to the hopper from a bulk raw material supply. Optionally the hopper may have agitation to assist in transfer of the solids from the hopper. The solids are often transferred through different stages of the apparatus using one or more augers. As used herein an auger is an axially rotatable screw feed. The auger may ultimately feed the solids into a mixer. One or more liquids may be added to the mixer. The mixer has an axially rotatable impeller for dispersing one or more solids throughout the liquid(s). The impeller may create a vacuum in the mixer, as an artifact of the centrifugal mixing process. The solid/liquid dispersion may be drained or pumped from the mixer. The dispersion may be used as a premix for yet another batch or continuous process or may be used as an end product. 
     It is typically important that the solids be thoroughly and uniformly dispersed throughout the liquid. Properties inherent to the solids may make proper dispersion more difficult to obtain. For example, as particle size decreases and cohesion and the propensity of the solids to hydrate increases, proper dispersion becomes more difficult. Likewise, properties inherent to the liquid may make proper dispersion more difficult to obtain. For example, as viscosity, temperature and backpressure at the mixer outlet increase, proper dispersion becomes more difficult. 
     Likewise, properties inherent to the apparatus may make proper dispersion of the solids into the liquid more difficult to obtain. For example the vacuum in the mixer may draw solids at an uncontrolled delivery rate. Instead of a constant supply rate, the solids may be supplied to the mixer at a variable supply rate. The variable supply rate may provide more solids at one point in time than can be dispersed by the impeller and less solids at a different point in time. While the impeller imparts a uniform shear rate at any radial position, differences in the amount of solids present may make uniform dispersion more difficult to obtain. 
     One example of a prior art apparatus is found in U.S. Pat. No. 5,547,276 issued Aug. 20, 1996 to Sulzbach et al. The Sulzbach et al. apparatus transfers solids from a storage vessel to an intermediate tank via a horizontally oriented screw. The solids are transferred from the intermediate tank to a mixing apparatus via a second horizontally oriented screw. Sulzbach et al. also shows a complex arrangement having a vacuum pump and a feedback control device deareates the solids in the intermediate tank. This complex arrangement increases the cost of the Sulzbach et al. apparatus. Furthermore, the horizontally oriented screw increases the apparatus&#39; footprint, increasing the operating cost due to the floor space requirements. 
     An example of the introduction of particulate material into a receiver is found in U.S. Pat. No. 6,021,821 issued Feb. 8, 2000 to Wegman. Wegman uses a vertically oriented auger to feed fluidized particulate material into a receiver. The receiver has a negative pressure, due to a vacuum assist of up to 10 inches (25.4 cm) of water. Wegman does not teach handling of particulate material under high differential pressure conditions, as often occurs when mixing solids and liquids together. Nor does Wegman teach how to handle materials, such as anthracite coal, or maltodextrin, which become floodable when subjected to fluidization. 
     The present invention provides an apparatus and method for achieving a controlled delivery rate of solids into a mixer, without the need for a deareating or evacuation step. The present invention also provides an apparatus and method for achieving controlled delivery of solids into a mixer for dispersion throughout one or more liquids or gasses. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic view of an apparatus according to the present invention and having a vertically oriented auger. 
     FIGS. 2-5 are graphical representations of exemplary solids delivery rates for various auger rotational speeds. 
    
    
     SUMMARY OF THE INVENTION 
     In one embodiment the invention comprises an apparatus for dispersing one or more solids into a liquid. The apparatus comprises a hopper for containing solids. The hopper has a hopper inlet for receiving solids therein and a hopper outlet for distributing solids therefrom. The hopper outlet is in communication with a throat. The throat has a throat inlet for receiving solids from the hopper, a throat outlet for discharging solids from the throat, and an axially rotatable auger disposed in the throat and rotatable at a variable rotational speed. A mixer is in communication with the throat outlet. The mixer has an agitator for mixing together solids and liquids disposed in the mixer. The mixer has a supply line for providing one or more liquids to the mixer. Axial rotation of the auger supplies a quantity of solids to the mixer. The solids are supplied to the mixer at a determinable delivery rate, which is proportional to the rotational speed of the auger over a range of auger rotational speeds. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, the apparatus  10  comprises a hopper  12 . Solids are placed in the hopper  12 . The hopper  12  has a throat  14  for discharging or otherwise distributing the solids therefrom. An auger  16  is disposed in the throat  14  of the hopper  12 . The throat  14  has an outlet in communication with a mixer  18 . At least one supply line provides one or more liquids to the mixer  18 . 
     The apparatus  10  provides for controlled distribution of the solids from the hopper  12  to the mixer  18 . By controlled distribution it is meant that the delivery rate of the solids into the mixer  18  is controlled within plus or minus 10 percent, and preferably plus minus 5 percent of a desired delivery rate by the operation of the auger  16  at various rotational speeds by simply adjusting the auger rotational speed. The controlled distribution, within the aforementioned limits, is independent of the pressure in either the hopper  12  or mixer  18 . 
     Examining the components in more detail, the hopper  12  may be any container suitable for receiving solids therein. The capacity of the hopper  12  is suitable for the intended purpose of controlled batch distribution of solids into the mixer  18 . The hopper  12  has a hopper inlet  20  for receiving the solids therein. The hopper inlet  20  is typically disposed near the top of the hopper  12 . The solids may be manually added to the hopper  12  or added by other mechanical means. The hopper  12  further has a hopper outlet  22  for discharging the solids from the hopper  12 . The hopper outlet  22  is typically located at or near the bottom of the hopper  12 . 
     The hopper  12  may be pressurized, to facilitate transfer of solids therefrom. Alternatively, the hopper  12  may be subjected to a subatmospheric pressure as described below to deareate the solids. Either condition will create a differential pressure across the throat  14  of the apparatus  10 , except in the degenerate case where an identical pressure exists in the mixer  18 . 
     The hopper  12  may have a lid, or other closure, to reduce dust which may occur during dispensing of solids into or from the hopper  12 . Optionally, the hopper  12  may have an impeller, air jets, or other form of mechanical agitation to reduce occurrences of irregular or inconsistent feeding of the solids from the hopper  12 . Optionally, the hopper  12  may have a deareating system, although the complexity of such a system is not necessary with the claimed invention. 
     A suitable hopper  12  may be a funnel hopper  12 , which converges in cross section as the hopper outlet  22  is approached. A control valve may be juxtaposed with the throat outlet  32 . The control valve may be used for throttling or more typically for on-off control. The control valve may be manually operated or operated by a control scheme, as set forth below. A butterfly valve is often used for the control valve. 
     If a control scheme is selected to guide operation of the control valve, the control scheme may open the valve on demand, admitting solids to the mixer  18  of the apparatus  10 . The valve may open in response to sensing the addition of a new batch of solids in the hopper  12 , on a timer, or manual input from an operator. The timing and rate of opening of the control valve may both be guided by the control scheme. 
     The control scheme may also guide the timing and closing rate of the control valve. For example, the control valve may be closed when the control scheme senses the hopper  12  is empty or nearly so, or when a predetermined amount of solids has entered the mixer  18 , based upon auger  16  rotations, gross weight of the mixer  18  or a timer. If desired, a feedback loop may be incorporated into the control scheme to operate the control valve in response to conditions in the hopper  12  and/or mixer  18 . The control scheme may also control the speed of the auger rotation, providing throttling capability. 
     The hopper outlet  22  is connected to and in communication with a throat inlet  30 . Solids enter the throat  14  through the throat inlet  30  and exit the throat  14  through a throat outlet  32 . The throat inlet  30  and throat outlet  32  define an axis therebetween and are axially opposed with respect to that axis. 
     In the embodiment of FIG. 1, the throat  14  may be vertically oriented. As used herein, vertically oriented refers to configurations where the axis is coincident true vertical or within plus or minus 15 degrees in a first embodiment and plus or minus 10 degrees of true vertical in a second embodiment. The throat  14  may be of any suitable cross section which seal the auger  16 , with a round cross section having been found most commonly used. The throat  14  may be of constant or variable cross section. 
     In an alternative embodiment (not shown) the auger  16  may be horizontally oriented or oriented at a position intermediate the horizontal and vertical. All such orientations in this alternative embodiment are referred to as non-vertical orientations. 
     An axially rotatable auger  16  is disposed in the throat  14 . The auger  16  is vertically oriented and coincident the true vertical in the embodiment of FIG.  1 . As used herein an auger  16  refers to a screw feed mechanism having one or more flights spiral wound about a central longitudinal axis in an involute fashion. The auger  16  has a proximal end juxtaposed with the hopper  12  and a distal end juxtaposed with the mixer  18 . The longitudinal axis of the auger  16  extends from the proximal end to the distal end of the auger  16 . The proximal end of the auger  16  may be disposed in the hopper  12 , further allowing the auger  16  to transport solids from the hopper  12  into the throat  14  and ultimately to the mixer  18  without starvation. 
     The flight of the auger  16  may be of constant diameter throughout its length, to form a free-flow auger  16 . In an alternative embodiment the portion of the flight disposed inside the hopper  12  may be of greater diameter than the portion of the flight disposed inside the throat  14 , to form a non-freeflow auger  16 . If, this alternative embodiment is selected, care should be taken that it does not lead to plugging of the solids in the throat  14 . Plugging may occur if the larger diameter flights in the hopper  12  feeds a greater quantity of solids than can be discharged through the throat  14 . 
     Furthermore, augers  16  having constant and variable flight diameters in the throat  14 , constant and variable root diameters, and constant and variable flight pitches are contemplated. Furthermore, multiple flights may be utilized, as well as flights which are continuous, discretely segmented and combinations thereof. 
     In the prior art, the delivery rate of the solids from hopper  12  is controlled by the vacuum created in the mixer  18 , any other differential pressure which may be present in the system, or the throttle valve (if any). In the present invention, the delivery rate of the solids from the throat outlet  32  may be controlled by the auger  16  rotational speed or by a combination of auger rotational speed and differential pressure. Auger  16  control of the solids delivery rate may be accomplished by sealing the throat  14  against excessive airflow therethrough. Of course, if a blanket of inert gas, or a compressible fluid other than air is used with the present invention, the sealing should prevent excessive flow of any such gas through the throat as well. 
     In order for a solids delivery rate controlled by auger  16  rotational speed to occur the auger  16  may seal the throat  14  against the differential pressure. To seal the throat, the auger  16  must have sufficient length, the annular clearance between the auger  16  and throat  14  must be minimal and the flight of the auger  16  preferably subtend at least 540 degrees. Generally, as the solids becomes more free flowing, the flight will have to subtend a greater number of revolutions to accomplish sealing. Auger  16 /throat  14  combinations which accomplish sealing in accordance with the present invention are called out in the illustrative examples below. 
     In order for a solids delivery rate controlled by auger  16  rotational speed to occur the auger  16  may seal the throat  14  against the differential pressure. To seal the throat, the auger  16  must have sufficient length, the annular clearance between the auger  16  and throat  14  must be minimal and the flight of the auger  16  preferably subtend at least 540 degrees. Generally, as the solids becomes more free flowing, the flight will have to subtend a greater number of revolutions to accomplish sealing. Auger  16 /throat  14  combinations which accomplish sealing in accordance with the present invention are called out in the illustrative examples below. 
     Directionally, greater sealing will occur as 1) the pitch of the auger  16  decreases since, the flights are more perpendicular to the direction of applied differential pressure, 2) multiple flights are used on the auger  16 , since more flights in the auger  16  reduces the void space in the throat  14 , 3) the auger  16 /throat  14  length increase, since there are more stages to reduce the effects of the differential pressure, 4) the throat  14  diameter decreases, since this reduces void space and total area over which the differential pressure can act, and 5) the hopper  12  is filled with a greater quantity of solids, as this will minimize entry of ambient air at the proximal end of the auger  16 . 
     Optionally, a drip washer may be added to the auger  16  to further increase sealing. Typically the drip washer is disposed on and attached to the distal end of the auger  16 . The drip washer may be rotatably attached to the auger  16 , or may rotate with the auger  16 . A drip washer is a plate, typically round, which occludes the throat  14 , and thereby promotes sealing. A round drip washer, utilized with a round throat  14  may have a diameter approximately one-half the diameter of the throat  14 . A larger or smaller diameter optional drip washer may be utilized, to provide more or less sealing of the throat  14 , respectively. 
     For free-flowing powders another device that may increase sealing is a small lip disposed in the throat  14 , and preferably juxtaposed with the throat outlet  32 . The lip is an annular ring which intrudes into the throat  14 , decreasing the diameter of the throat outlet  32 . The inner diameter of the lip may be slightly larger than the diameter of the auger  16  and smaller than the diameter of the throat  14 . 
     Additionally, selection of the solids may influence the sealing of the throat  14 . Solids vary in cohesiveness, flowability, packing density, and other farinaceous characteristics. As the packing density of the solids increases, less air entrained in the solids will be transmitted through the throat  14 . Less air entrainment will allow greater sealing to occur. 
     The auger  16  may rotate about its axis at a rate dependent upon the diameter of the auger  16 , the number and pitch of the flights, and desired flow rate of the solids. The direction of axial rotation will be that which propels the solids from the hopper  12  towards the mixer  18 . While a single hopper  12 /throat  14 /auger  16  combination feeding the mixer  18  is illustrated, embodiments having two or more hopper  12 /auger  16 /throat  14  combinations feeding a single mixer  18  are also contemplated. If solids from multiple hopper  12 s feed a single mixer  18 , the hoppers  12  may contain the same or different solids. 
     While a hopper  12  disposed vertically above the mixer  18  is illustrated in FIG. 1, an embodiment where the hopper  12  is disposed vertically below the mixer  18  is also contemplated. If an embodiment having the mixer  18  disposed vertically above the hopper  12  is selected, care should be taken that liquid in the mixer  18  does not prematurely wet the solids in the throat  14 , although premature wetting is a consideration in any embodiment of the present invention. 
     The throat  14  expels or otherwise discharges the solids into a mixer  18 . The mixer  18  is typically sealed to maintain the aforementioned differential pressure, but may be open to the atmosphere if the hopper  12  has a subatmoshpheric pressure therein. In an exemplary embodiment the mixer  18  is sealed to prevent contamination and spilling of contents. 
     At least one supply line is provided to the mixer  18 . Each supply line provides a liquid to the mixer  18 . The liquid in each supply line may comprise a single component, multiple components, one or more gasses, or a mixture of liquids and solids. 
     An agitator is provided in the mixer  18 . The agitator is commonly an axially rotatable impeller. Additionally, a shaker which cyclically disturbs the entire mixer  18 , magnetic stir bars or other means known in the art may be used as the agitator. A rotatable impeller may have either a vertical or horizontal shaft impeller. 
     Upon agitation a vacuum may be created in the mixer  18 . In the most common embodiment, the vacuum occurs due to the centrifugal effect of the impeller throwing the contents of the mixer  18  outwardly. The centrifugal action creates a void in the center of the mixer  18 . The void creates a low pressure zone, i.e. vacuum. The vacuum will cause a differential pressure across the throat  14 , except for the degenerate case where an identical pressure is maintained in the hopper  12 . Prophetically a positive pressure may be maintained in the mixer  18 . A positive pressure will occur if the mass flow rate of liquid from the one or more supply lines exceeds the mass flow rate being discharged from the mixer  18 . Again, a positive pressure in the mixer  18  will cause a differential pressure across the throat  14 , except for the degenerate case where an identical pressure is maintained in the hopper  12 . 
     Using the present invention, solids and liquids may be added to the apparatus  10  in a continuous process, unlike the batch processes found in the prior art. The continuous process is made possible by the controlled and predeterminable solids delivery rate occurring at certain auger  16  rotational speeds. Further, since the solids delivery rate can be determined by the positive delivery provided by the auger  16  control, a greater quantity of solids can prophetically be delivered with the invention than according to the prior art. This allows a mixture with a higher solids concentration to be produced. Likewise, the present invention allows higher viscosity liquids to be used in the mixer  18 . For example, liquids with viscosities as high as 50,000 or 75,000 centipoises may be used in the mixer  18  with the present invention. The prior art apparatus  10  were generally unable to use high viscosity liquids, due to the difficulty of stirring with an impeller. The high viscosity liquids generally do not create a vortex, and thus do not cause a subatmospheric pressure to be formed in the mixer  18 . However, the present invention neither needs nor relies upon a subatmospheric pressure to supply solids to the mixer  18  at certain controlled delivery rates. 
     In an alternative embodiment the apparatus  10  of the present invention may be used to disperse solids into a gas. This may be particularly useful in, for example, pneumatic conveying. This apparatus  10  provides the advantage that controlled metering of the solids into a pressurized gas flow may be readily accomplished. 
     The apparatus  10  and method according to the present invention operate in three different regimes, dependent upon auger rotational speed: a substantially vacuum controlled regime, a regime substantially controlled by a combination of the vacuum and auger rotational speed, and a regime controlled by the auger rotational speed. In operation it is believed that at relatively slower auger  16  rotational speeds the solids delivery rate is controlled by the differential pressure across the throat  14  in which the auger  16  is disposed. Particularly, the solids delivery rate is controlled by the vacuum in the mixer  18 . This effect can be graphically displayed by noting that as auger  16  rotational speed increases over a range, the solids delivery rate remains relatively constant over the same range. As the auger  16  rotational speed increases, a transition region occurs. In the transition region the solids delivery rate is controlled by the superposition of the auger  16  rotational speed and the mixer  18  vacuum or other differential pressure. As the auger  16  rotational speed increases further, the solids delivery rate is substantially controlled by the auger  16  rotational speed. This may be graphically illustrated by the linear increase in solids delivery rate over that same range of auger  16  rotational speeds. 
     To determine which phenomenon is controlling the solids delivery rate, i.e. in which of the three regimes the apparatus  10  is operating, the following approach may be used. At any particular auger  16  rotational speed the actual solids delivery rate is compared to the theoretical solids delivery rate. If the actual solids delivery rate is greater than the theoretical solids delivery rate, the apparatus is operating in the vacuum controlled regime or the combination vacuum and auger rotational speed controlled regime. To determine in which of these two regimes the apparatus is operating, the slope of the graph, as illustrated in FIGS. 2-5, is examined. If the slope is negligible between any two auger rotational speeds, the vacuum is controlling the solids delivery rate. Conversely, if the slope is positive, the combination of vacuum and auger rotational speed is controlling the solids delivery rate. If the actual solids delivery rate is less than the theoretical solids delivery rate, then the auger rotational speed is controlling the solids delivery rate. One of skill will understand that a positive pressure in the mixer  18  or a positive/subatmospheric pressure in the hopper  12  may be present and the foregoing analysis adjusted accordingly. 
     For Examples 1-2, auger  16  rotational speed was measured with a tachometer. For Examples 3-4 auger  16  rotational speed was measured directly from the drive to the auger  16 . 
     The various facets of the invention and the different regimes of vacuum control, vacuum/auger  16  rotational speed control and auger  16  rotational speed control of the solids delivery rate are collectively illustrated by the following nonlimiting, illustrative examples. 
     EXAMPLE 1 
     A pilot scale Mateer-Burt 1900 auger  16  filler was provided. A funnel hopper  12  and model 7510-130 F1114 LMP Tri-blender mixer  18  were provided. A vertically oriented no.  20  free flow auger  16  having a diameter of 3.18 cm. (1.25 inch) and a single flight with a pitch of 3.8 cm (1.5 inch) was also provided and disposed as illustrated in FIG.  1 . The auger  16  had a length of 15.2 cm (6 inches). The auger  16  was disposed such that 10.2 cm (4 inches) of its length was disposed in the throat  14  and 5.1 cm (2 inches) extended into the hopper  12 . A 3.2 mm (⅛ inch) radial clearance was provided between auger  16  and the throat  14 . The auger  16  was run without a drip washer. 
     The hopper  12  was filled with solids comprising Polyox Peg-7M, CAS no. 25322-68-3. For the test runs, water was added to the mixer at a rate of approximately 40 kg/min. 
     The mixer  18  was agitated with a vertical impeller, capable of rotating at 3600 rpm, and creating a vacuum of 700 mm Hg. The mixer  18  was run without operation of the impeller, and thus without vacuum, for the control and with rotation of the impeller during testing. The results for the control (no mixer  18  vacuum) and test runs (with mixer  18  vacuum) are tabulated in Tables 1-2 respectively. 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                   
                 Powder Solids 
                   
               
               
                   
                   
                   
                 Delivery Rate 
                 Slope 
               
               
                 Vacuum 
                 Solids 
                 Auger RPM 
                 (kg/min) 
                 (kg*rpm/min) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 None 
                 Polyox 
                 0 
                 0.3 
                 — 
               
               
                 None 
                 Polyox 
                 47 
                 0.6 
                 0.006 
               
               
                 None 
                 Polyox 
                 132 
                 1.1 
                 0.006 
               
               
                 None 
                 Polyox 
                 227 
                 1.8 
                 0.007 
               
               
                   
               
            
           
         
       
     
     Table .1 illustrates that even with the auger  16  off (0 RPM) the solids slowly fed out of the hopper  12 . Eventually the throat  14  became clogged, stopping the solids flow. Table 1 also illustrates that solids delivery rate is controllable by auger  16  rotational speed, over the range from 47 to 227 rpm when a differential pressure is not present across the auger  16 . 
     Next the mixer  18  impeller was activated and the test repeated with a vacuum in the mixer  18 . The results are tabulated in Table 2. 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                   
                   
                   
                 Powder Solids 
                   
               
               
                   
                   
                   
                 Delivery Rate 
                 Slope 
               
               
                 Vacuum 
                 Solids 
                 Auger RPM 
                 (kg/min) 
                 (kg*rpm/min) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Yes 
                 Polyox 
                 0 
                 0.86 
                 — 
               
               
                 Yes 
                 Polyox 
                 0 
                 2.2 
                 — 
               
               
                 Yes 
                 Polyox 
                 0 
                 0.7 
                 — 
               
               
                 Yes 
                 Polyox 
                 0 
                 0.8 
                 — 
               
               
                 Yes 
                 Polyox 
                 47 
                 2.1 
                 0.028 
               
               
                 Yes 
                 Polyox 
                 100 
                 2.3 
                 0.004 
               
               
                 Yes 
                 Polyox 
                 132 
                 2.4 
                 0.003 
               
               
                   
               
            
           
         
       
     
     Note, the 2.2 kg/min datum point is likely an outlier and was not further considered. The slope from 0 to 47 rpm was determined using an average of the other three solids delivery rates at 0 rpm. Table 2 illustrates that solids delivery rate is independent of auger  16  speed, and thus is substantially controlled by the mixer  18  vacuum. 
     The common data in Tables 1 and 2 are combined to show the difference in solids delivery rate attributable to the vacuum occurring in the mixer  18 . The percentage differences in solids delivery rates and slope are tabulated in Tables 3 and 4 below, respectively. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                   
                 Control 
                 Test 
                 Percent 
               
               
                   
                 Polyox Solids 
                 Polyox Solids 
                 Difference 
               
               
                 Auger Speed 
                 Delivery Rate 
                 Delivery Rate 
                 In Solids Delivery 
               
               
                 (RPM) 
                 (kg/min) 
                 (kg/min) 
                 Rates 
               
               
                   
               
             
            
               
                  47 
                 0.6 
                 2.1 
                 250 
               
               
                 132 
                 1.1 
                 2.4 
                 118 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                   
                 Control 
                 Test 
                 Percent 
               
               
                   
                 Auger Speed 
                 Polyox Slope 
                 Polyox Slope 
                 Difference 
               
               
                   
                 (RPM) 
                 (kg*rpm/min) 
                 (kg*rpm/min) 
                 In Slopes 
               
               
                   
                   
               
             
            
               
                   
                  47 
                 0.006 
                 0.004 
                 33 
               
               
                   
                 132 
               
               
                   
                   
               
            
           
         
       
     
     EXAMPLE 2 
     A pilot scale Mateer-Burt 1900 auger  16  filler was provided. A funnel hopper  12  having a 40 rpm internal agitator arm and a model 7510-130 F1114 LMP Tri-blender mixer  18  were provided. A vertically oriented no.  16  free flow auger  16  having a constant diameter of 2.54 cm. (1 inch) and a single flight with a pitch of 1.3 cm (0.5 inch) was also provided and disposed as illustrated in FIG.  1 . The auger  16  had a length of 35.6 cm (14 inches). The auger  16  was disposed such that 30.5 cm (12 inches) of its length was disposed in the throat  14  and 5.1 cm (2 inches) extended into the hopper  12 . A 3.2 mm (⅛ inch) radial clearance was provided between the auger  16  and the throat  14 . The auger  16  was run without a drip washer. 
     The mixer  18  was agitated with a vertical impeller, capable of rotating at 3600 rpm, and creating a vacuum of 700 mm Hg. The mixer  18  was run without operation of the impeller, and thus without vacuum, for the control and with rotation of the impeller during testing. Likewise, the hopper  12  internal agitator was used at 40 rpm. 
     The hopper  12  was filled with polyquaternium-10 LR 400 CAS no. 53568-66-4, Mainline LR 400 solids. Ammonium Laureth Sulfate surfactant, CAS no. 32612-48-9 at a temperature of 63-77 degrees C was added to the mixer  18  at a rate of approximately 40 kg/min. for the test runs. 
     The results for the control (no mixer  18  vacuum) and test runs (with mixer  18  vacuum) are tabulated in Tables 5-6 respectively. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 5 
               
               
                   
               
               
                   
                   
                   
                 Auger 
                 Mainline LR 400 
                   
               
               
                   
                   
                 Agitator 
                 Speed 
                 Solids Delivery 
                 Slope 
               
               
                 Vacuum 
                 Solids 
                 Arm 
                 (RPM) 
                 Rate (kg/min) 
                 (kg/rpm/min) 
               
               
                   
               
             
            
               
                 None 
                 Mainline 
                 40 rpm 
                 251 
                 0.48 
                 — 
               
               
                   
                 LR 400 
               
               
                 None 
                 Mainline 
                 40 rpm 
                 379 
                 0.71 
                 0.002 
               
               
                   
                 LR 400 
               
               
                 Nore 
                 Mainline 
                 40 rpm 
                 509 
                 1.01 
                 0.002 
               
               
                   
                 LR 400 
               
               
                   
               
            
           
         
       
     
     The data from Table 5 are graphically illustrated in FIG.  2 . FIG. 2 illustrates that the auger  16  speed was controlling the solids delivery rate for the control 
     Next, the mixer  18  impeller was activated and the test repeated. The results are shown in Table 6 below and graphically illustrated in FIG.  3 . FIG. 3 shows that auger  16  speed is controlling the solids delivery rate. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 6 
               
               
                   
               
               
                   
                   
                   
                 Auger 
                 Mainline LR 400 
                   
               
               
                   
                   
                 Agitator 
                 Speed 
                 Solids Delivery 
               
               
                 Vacuum 
                 Solids 
                 Arm 
                 (RPM) 
                 Rate (kg/min) 
                 Slope 
               
               
                   
               
             
            
               
                 Yes 
                 Mainline 
                 40 rpm 
                 251 
                 0.53 
                 — 
               
               
                   
                 LR 400 
               
               
                 Yes 
                 Mainline 
                 40 rpm 
                 251 
                 0.55 
               
               
                   
                 LR 400 
               
               
                 Yes 
                 Mainline 
                 40 rpm 
                 379 
                 0.71 
                 0.001 
               
               
                   
                 LR 400 
               
               
                 Yes 
                 Mainline 
                 40 rpm 
                 509 
                 0.92 
                 0.002 
               
               
                   
                 LR 400 
               
               
                 Yes 
                 Mainline 
                 40 rpm 
                 509 
                 0.98 
               
               
                   
                 LR 400 
               
               
                   
               
            
           
         
       
     
     The data in Tables 5 and 6 are combined to show the difference in solids delivery rate attributable to the vacuum occurring in the mixer  18 . The solids delivery rates at 251 and 509 rpm in Table 6 were averaged for purposes of comparison with the delivery rates in Table 5. The percentage differences in solids delivery rate and slope are tabulated in Tables 7-8, respectively. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 7 
               
               
                   
               
               
                   
                 Control 
                 Test 
                 Percent 
               
               
                   
                 Mainline LR 400 
                 Mainline LR 400 
                 Difference In 
               
               
                 Auger Speed 
                 Solids Delivery 
                 Solids Delivery 
                 Solids Delivery 
               
               
                 (RPM) 
                 Rate (kg/min) 
                 Rate (kg/min) 
                 Rates 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 251 
                 0.48 
                 0.54 
                 12.5 
               
               
                 379 
                 0.71 
                 0.71 
                 0 
               
               
                 509 
                 1.01 
                 0.95 
                 5.9 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
             
               
                 TABLE 8 
               
               
                   
               
               
                   
                 Control 
                 Test 
                   
               
               
                   
                 Mainline LR 400 
                 Mainline LR 400 
                 Percent 
               
               
                 Auger Speed 
                 Slope 
                 Slope 
                 Difference 
               
               
                 (RPM) 
                 (kg*rpm/min) 
                 (kg*rpm/min) 
                 In Slopes 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 251 
                 — 
                 — 
                 — 
               
               
                 379 
                 0.002 
                 0.001 
                 50 
               
               
                 509 
                 0.002 
                 0.002 
                  0 
               
               
                   
               
            
           
         
       
     
     EXAMPLE 3 
     A Tri-clover, Inc. model F2116MD triblender was used to mix the liquid and solids. A 56 cm (22 inch) diameter model A-100 auger  16  feeder system made by AMS Filling Systems, Inc. was used to contain and dispense the solids to the mixer  18 . The hopper  12  was filled with maltodextrin M-180, CAS No. 9050-36-6. Water at room temperature was added at a rate of 110-120 kg/min for the test runs. 
     A vertically oriented number  20  free flow funnel and free flow auger  16  having a diameter of 3.18 cm. (1.25 inch) and a single flight with a pitch of 3.8 cm (1.5 inch) was also provided and disposed as illustrated in FIG.  1 . The results for the control (no mixer  18  vacuum) and test runs (with mixer  18  vacuum) are tabulated in Tables 9-10, respectively. The data from the control (no vacuum) and test runs (with vacuum) are shown in Table 9 and graphically illustrated in FIG.  4 . 
     For this example, the theoretical volume per flight within the auger  16  was taken from the GE: Mateer Auger Data Guide, copyrt. 1991 and incorporated herein by reference. For the examples where a non-standard auger  16  was used, the theoretical volume per flight within the auger  16  was calculated using a water displacement method. 
     The theoretical volume was used to calculate a theoretical delivery rate. This was compared to the actual delivery rate with the vacuum from the mixer  18  present. If this actual delivery rate exceeded the theoretical delivery rate, the apparatus  10  was judged to be delivering solids at a delivery rate controlled by the vacuum or by a combo of a vacuum and auger  16  rotational speed. If the actual delivery rate was less than the theoretical delivery rate, the apparatus  10  was judged to be delivering solids at a delivery rate controlled by the rotational speed of the auger  16 . 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 9 
               
             
            
               
                   
                   
               
               
                   
                   
                   
                 Test 
               
               
                   
                   
                 Control 
                 Solids Delivery Rate 
               
               
                   
                 Theoretical 
                 Solids Delivery Rate 
                 (with vacuum) (Kg/min) 
               
            
           
           
               
               
               
               
               
            
               
                 Auger 
                 Auger Volume 
                 (without vacuum) (Kg/min) 
                   
                 Percent difference 
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Rotational Speed 
                 per Revolution 
                 Calculated 
                 Actual 
                 Percent 
                 Actual 
                 vs. calculated 
               
               
                 (RPM) 
                 (Kg) 
                 Delivery Rate 
                 Delivery Rate 
                 Difference 
                 Delivery Rate 
                 delivery rate 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                  50 
                 1.59 
                 0.88 
                 0.61 
                 70% 
                 3.41 
                 390% 
               
               
                 100 
                 3.18 
                 1.75 
                 1.24 
                 71% 
                 3.45 
                 197% 
               
               
                 150 
                 4.77 
                 2.62 
                 1.80 
                 69% 
                 5.20 
                 198% 
               
               
                 200 
                 6.36 
                 3.50 
                 2.40 
                 68% 
                 6.03 
                 172% 
               
               
                 300 
                 9.54 
                 5.247 
                 3.55 
                 68% 
                 7.30 
                 139% 
               
               
                 400 
                 12.72 
                 6.99 
                 4.80 
                 69% 
                 8.62 
                 123% 
               
               
                 500 
                 15.90 
                 8.75 
                 6.31 
                 72% 
               
               
                 600 
                 19.08 
                 10.49 
                 7.57 
                 72% 
                 9.54 
                  91% 
               
               
                   
               
            
           
         
       
     
     Table 9 shows that the actual solids delivery rate with vacuum exceeds the theoretical solids delivery rate for auger  16  rotational speeds of 0 to 400 rpm. Therefore, the vacuum in the mixer  18  is either controlling or making a contribution to the solids delivery rate. Referring to FIG. 4, the negligible slope from 0 to 100 rpm illustrates the solids delivery rate is controlled by the vacuum over this range of auger  16  rotational speeds. FIG. 4 also illustrates that from 100 to 400 rpm the solids delivery rate is controlled by a combination of the vacuum and the auger  16  rotational speed. At auger  16  rotational speeds of 600 rpm and greater, the solids delivery rate is controlled by the auger  16  rotational speed. 
     EXAMPLE 4 
     The apparatus  10  and conditions of Example 3 were used for Example 4, except as follows. The hopper  12  was filled with Citric Acid, CAS No. 77-92-9. A number  28  free flow auger  16  having a 4.45 cm (1.75 inch) diameter and free flow funnel were used. The auger  16  had a 3.8 cm (1.5 inch) pitch. The control and test data are shown in Table 10. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 10 
               
             
            
               
                   
                   
               
               
                   
                   
                   
                 Test 
               
               
                   
                   
                 Control 
                 Solids Delivery Rate 
               
               
                   
                 Theoretical 
                 Solids Delivery Rate 
                 (with vacuum) (g/min) 
               
            
           
           
               
               
               
               
               
            
               
                 Auger 
                 Auger Volume 
                 (without vacuum) (g/min) 
                   
                 Percent difference 
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Rotational Speed 
                 per Revolution 
                 Calculated 
                 Actual 
                 Percent 
                 Actual 
                 vs. calculated 
               
               
                 (RPM) 
                 (g) 
                 Delivery Rate 
                 Delivery Rate 
                 Difference 
                 Delivery Rate 
                 delivery rate 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                  50 
                 3315.0 
                 2983.5 
                   
                   
                   
                   
               
               
                 100 
                 6630.0 
                 5967.0 
                  4225 
                 71% 
                 4040 
                 68% 
               
               
                 150 
                 9945.0 
                 8950.5 
                   
                   
                 6100 
                 68% 
               
               
                 200 
                 13260.0 
                 11934.0 
                  8559 
                 72% 
                 7860 
                 66% 
               
               
                 300 
                 19890.0 
                 17901.0 
                 12076 
                 67% 
               
               
                 400 
                 26520.0 
                 23868.0 
                 15788 
                 66% 
               
               
                 500 
                 33150.0 
                 29835.0 
                 19406 
                 65% 
               
               
                 600 
                 39780.0 
                 35802.0 
                 22517 
                 63% 
               
               
                   
               
            
           
         
       
     
     Table 10 illustrates that for auger rotational speed of 100-200 rpm the actual solids delivery rate is less than the theoretical solids delivery rate. Accordingly, the auger  16  rotational speed is controlling the solids delivery rate for this range of auger  16  rotational speeds. Since the actual solids delivery rate was less than the theoretical solids delivery rate at the slower auger  16  rotational speeds, it was deemed unnecessary to run the test at higher auger  16  rotational speeds. 
     EXAMPLE 5 
     The apparatus  10  and conditions of Example 3 were used for Example 5, except as follows. The hopper  12  was again filled with maltodextrin M-180, CAS No. 9050-36-6. A number  28  free flow auger  16  having a diameter of 4.45 cm (1.75 inches) free flow funnel were used. The auger  16  had a 2.5 cm (1 inch) pitch. The control test data are shown in Table 11 and graphically illustrated in FIG.  5 . 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 11 
               
             
            
               
                   
                   
               
               
                   
                   
                   
                 Test 
               
               
                   
                   
                 Control 
                 Solids Delivery Rate 
               
               
                   
                 Theoretical 
                 Solids Delivery Rate 
                 (with vacuum) (g/min) 
               
            
           
           
               
               
               
               
               
            
               
                 Auger 
                 Auger Volume 
                 (without vacuum) (g/min) 
                   
                 Percent difference 
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Rotational Speed 
                 per Revolution 
                 Calculated 
                 Actual 
                 Percent 
                 Actual 
                 vs. calculated 
               
               
                 (RPM) 
                 (g) 
                 Delivery Rate 
                 Delivery Rate 
                 Difference 
                 Delivery Rate 
                 delivery rate 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                  50 
                 2110.0 
                 1160.5 
                   
                   
                   
                   
               
               
                 100 
                 4220.0 
                 2321.0 
                 1500 
                 65% 
                 2780 
                 120% 
               
               
                 150 
                 6330.0 
                 3481.5 
               
               
                 200 
                 8440.0 
                 4642.0 
                 3023 
                 65% 
                 4140 
                  89% 
               
               
                 300 
                 12660.0 
                 6963.0 
                 4504 
                 65% 
                 5400 
                  78% 
               
               
                 400 
                 16880.0 
                 9284.0 
                 5927 
                 64% 
               
               
                 500 
                 21100.0 
                 11605.0 
                 7376 
                 64% 
               
               
                 600 
                 25320.0 
                 13926.0 
                 8742 
                 63% 
               
               
                   
               
            
           
         
       
     
     Table 11 illustrates that at 100 rpm the mixer  18  vacuum is either controlling or contributing to the solids delivery rate. Without examining the slope of the line corresponding to the solids delivery rate vs auger  16  rotational speed, it is difficult to determine under which of these two regimes the apparatus  10  is operating. Table 11 also shows that at 200-300 rpm the actual solids delivery rate is less than the theoretical solids delivery rate. Thus, at this range of auger  16  rotational speeds the auger  16  rotational speed controls the solids delivery rate.