Patent Publication Number: US-2018045625-A1

Title: Portable self-cleaning aggregrate mixture analysis unit

Description:
BACKGROUND INFORMATION 
     Field of the Invention 
     The invention relates to the field of composition analysis of aggregate materials. Further, the invention relates to equipment that is used to analyze the components of an aggregate particle mixture, such as those that are used to make asphalt concrete. 
     Discussion of Prior Art 
     Roadways, parking lots, and other surfaces that are intended to be used with wheeled vehicles are often covered in a composite material such as asphalt concrete or flexible pavement. These composite materials are composed of a mixture of variously sized aggregate particles, such as sand, gravel, crushed stone and slag, which are combined with a binder such as asphalt or bitumen. There are a number of well-known composite material mixture formulations, which combine a mixture of different size aggregate particles with various amounts of binders to create the preferred composite material for a specific purpose and to meet various standards and regulations. 
     The particle size distribution in the mixture of aggregate particles is one of the most influential characteristics in determining how the composite material will perform as, for example, a pavement material because the particle mixture composition influences the stiffness, stability, durability, permeability, workability, skid resistance and resistance to moisture damage of the pavement. For example, a mixture that does not contain sufficient large sized particles may result in a composite material that lacks stability. Alternatively, a mixture that contains too high a percentage of large particles may result in a composite material that has poor workability. 
     While various aggregate mixture formulations are known, the different formulations are not available as premixed compositions; rather, the various aggregates must be purchased separately and mixed together to obtain the composition that corresponds to a project specification. 
     The blending process generally involves combining and mixing an estimated amount of variously sized particles in a mixer, using a scale to weigh the mixture, transporting the mixture to a drying machine to dry the mixture, using a scale to weigh the dry mixture, using a sorting mechanism to sort the aggregate particles by particle size and then using the scale to weigh each size group. Then analyzing weights to determine whether the mixture has the desired composition. These test steps typically result in a cumbersome process that involves numerous machines and that allow for a great deal of human error. And, typically, these tests may only be done in a lab rather than at a mixing site, thus introducing additional delay, cost, and opportunity for human error. 
     What is needed, therefore, is a conveniently sized portable test unit that is capable of sorting and analyzing the mixture of aggregates at a worksite. What is further needed is such a test unit that is in a ready-to-use condition after a test has been completed. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention is a portable self-cleaning aggregate material analysis device that accepts a sample of an aggregate particle mixture, captures the weight of the initial sample, dries the sample, and separates and sorts the sample by particle size, and then captures the weight of those particle size groupings to determine the composition of the sample aggregate mixture, then displays the information to a user, and washes away residual sample material, so that the device is ready to use for a new test. 
     The device includes a material analysis chamber that accepts the sample of an aggregate mixture and includes a sorting unit and a weighing mechanism. The weighing mechanism captures the wet weight of the aggregate mixture sample and relays the information to a user via an integrated computer system. A moisture evacuation system is connected to the outside of the material analysis chamber and dries the sample material by evacuating the moisture from the chamber after the wet weight is recorded. The weighing mechanism measures the dry weight of the aggregate mixture sample and relays that data to the computer system. The sorting unit then separates the dry aggregate mixture sample into individual particles and sorts those particles by particle size. The weighing mechanism then captures the weight of each group of particles. 
     The sorting unit includes a sieve container that holds a plurality of sieves, the sieve container having an approximately cylindrical sidewall, an open top, and a closed bottom. The sieves are fixed in the horizontal plane within the material analysis chamber, but movable in the vertical plane. The sieves have apertures that are approximately uniformly sized within a single sieve, but that vary between sieves, and are stacked inside the sieve container with the sieve at the top of the stack having the largest apertures and each successively lower sieve having slightly smaller apertures. As the sample material is separated into particles, the particles fall through the sieves having apertures that are larger than the particle size until the particles land in, and are contained by, a sieve having apertures smaller than the particle. 
     The sorting unit also includes a vertical oscillation mechanism to facilitate the particles falling through the sieves. This vertical oscillation mechanism includes an oscillator ring having an upper edge that is a vertical displacement contour. The ring is rotatably affixed in the base of the material analysis chamber and is connected to a motor located outside of the material analysis chamber. Actuating the motor causes the oscillator ring to rotate. A plurality of wheels are affixed to the bottom of the sieve container&#39;s sidewall and sit on top of the oscillator ring. As the ring rotates beneath the wheels, the displacement contour on the ring forces the sieve container to oscillate in the vertical plane, thereby causing the aggregate particles fall through the sieves that have sieve apertures that are larger than their particle size. 
     Following the test, the computer system relays the moisture content of the aggregate mixture and the ratio of particles sizes contained within the sample, the particles are manually removed from the device and a washing system cleans the chamber of all sample material residue to prepare the chamber for further sample material analysis. The device is relatively small and light, such that it is portable and may be transported in the back of an average size pickup truck and easily moved by two or more individuals having average physical capabilities. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is described with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. The drawings are not drawn to scale. 
         FIG. 1  is a perspective view of the device according to the invention. 
         FIG. 2  is a side view of the device. 
         FIG. 3  is a perspective view of the device encased in a chassis. 
         FIG. 4  is a perspective view of the chassis with an open lid. 
         FIG. 5  is a top view of the material analysis chamber with the sieve container. 
         FIG. 6  is a partial top view of the material analysis chamber without the sieve container. 
         FIG. 7  is a partial side view of the sieve container showing the wheels, guide posts and the material analysis chamber&#39;s oscillating ring. 
         FIG. 8  is a side view of the sieve containers wheel on the material analysis chamber&#39;s oscillating ring. 
         FIG. 9  is top view of the sieve container showing the inside of the unit. 
         FIG. 10  is a top view of the sieve container loaded with sieve support rings. 
         FIG. 11  is a perspective view of the elevator post and gears. 
         FIG. 12  is a top plan view of a sieve support ring. 
         FIG. 13  is a top plan view of the sieve. 
         FIG. 14  is a perspective view of the stepper motors that drive the elevator post and oscillating ring. 
         FIG. 15  is a partial cut-away view showing the motors connected to the gear and threaded rod. 
         FIG. 16  is a front view of the moisture evacuating unit. 
         FIG. 17  is a side view of the moisture evacuating unit. 
         FIG. 18  is a perspective view of the washing unit. 
         FIG. 19  is a front view of the washing unit. 
         FIG. 20  is a side view of the washing unit. 
         FIG. 21  is a perspective view of a portion of the washing unit showing the water pumps. 
         FIG. 22  is a side view of the computer system contained with the chassis lid. 
         FIG. 23  is a cross-sectional view of the device chamber. 
         FIG. 24  is a perspective view of the ring rack with the rings. 
         FIG. 25  is a perspective view of the ring rack without the rings. 
         FIG. 26  is a side view of the ring rack and weighing mechanism with the weighing mechanism in a lowered position. 
         FIG. 27  is a side view of the ring rack and weighing mechanism with the weighing mechanism in a top position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will now be described more fully in detail with reference to the accompanying drawings, in which the preferred embodiments of the invention are shown. This invention should not, however, be construed as limited to the embodiments set forth herein; rather, they are provided so that this disclosure will be complete and will fully convey the scope of the invention to those skilled in the art. 
       FIGS. 1-4  illustrate the portable self-cleaning aggregate mixture analysis unit  100  according to the invention, including a material analysis chamber  10  for holding a sorting unit  30  and weighing unit  49 , each shown in  FIGS. 5-11 , a moisture evacuating unit  60 , a washing unit  80 , and a computer control system  90 , which analyzes the contents of aggregate materials, such as used to create asphalt concrete. The material analysis chamber  10  is approximately cylindrical in shape having a sidewall  11  and a lid  13 . In the embodiment shown, all of these components are contained within a chassis  2  that has a chassis lid  4  and is mounted on a movable base that is fitted with wheels or castors, and that is sized so as to be easily portable, for example, in the back of a standard size pickup truck. 
     To use the aggregate mixture analysis device  100  a user places an aggregate mixture sample (not shown) into the sorting unit  30  and closes the lid  13 . Closing the lid creates an air tight seal of the material analysis chamber. Most samples contain a small amount of moisture, and the weighing unit  49  is first used to measure the wet weight of the sample. The moisture evacuating unit  60  then uses a vacuum pump  64  to vent the moisture out from the material analysis chamber  10  to dry the sample. The dry weight of the sample is measured and the computer control system  90  calculates the percentage of moisture in the sample, based on the difference of wet to dry weight. The sorting unit  30  then sorts the aggregate mixture by particle size, and the weighing unit  49  weighs each size group. Once the test is completed, a user manually empties the sorting unit  30  and actuates the washing unit  80  to wash away any leftover sample particles and particle residue from the sorting unit  30 . 
       FIGS. 5-10  illustrate a first embodiment of the material analysis chamber  10  and the sorting unit  30 . In this embodiment, the material analysis chamber  10  has a plurality of guide tracks  12 , shown in  FIGS. 5 and 6 . The sorting unit  30  includes a sieve container  31 , illustrated in  FIGS. 5, and 7-10 . The container  31  is similar in shape to that of the material analysis chamber  10 , but smaller, and with a plurality of guide posts  46 . This sieve container  31  has a sidewall  32 , a bottom  34 , and an open top  36  and fits into the material analysis chamber  10 , with the guide posts  46  fitting into the guide tracks  12  on the chamber, so as to fix the position of the sieve container  31  in the horizontal plane inside the material analysis chamber. 
     The sieve container  31  contains a graduated sieve unit that includes a plurality of screens or sieves  44 , shown in  FIG. 13 , and a corresponding plurality of sieve support rings  42 , shown in  FIG. 12 . Each sieve  44  comprises a sidewall made of a rigid material and a sieve plate  43  constructed of a suitable mesh material that has a plurality of sieve apertures  45 . The sieves  44  are approximately circular in shape and are sized to sit loosely sit on top of the sieve support rings  42 . A series of stepped ring mounts  38  are provided along the inner surface of the container sidewall  32  for supporting the plurality of sieve support rings  42 . The sieve apertures  45  are uniform within a single sieve  44  but vary in size between the sieves  44 , with the sieve  44  at the top of the sieve container  31  having the largest apertures  45  and each successively lower sieve  44  having slightly smaller apertures  45 . The size of the apertures may vary depending on the intended application; however, for example, apertures ranging in size from  19  millimeters to  7 . 5  microns are often reasonable. The sieves  44  may also sit directly on the stepped ring mounts  38 , however, it is common for some sieve plates  43  to be made of thin materials and in these instances the sieve support rings  42  provide support for the sieve plates  43 . 
     The sorting unit  30  has a vertical oscillator  33  that is used to separate the aggregate particles and sort the particles into the plurality of sieves  44 . The vertical oscillator  33  includes an oscillation ring  14 , shown in  FIGS. 7 and 8 , that is positioned in the bottom of the material analysis chamber  10  and fixedly connected to a first gear  16 , shown in  FIGS. 6 and 11 . The first gear  16  meshes with a second gear  18  that is attached to a first stepper motor  22 , which is shown in  FIGS. 14 and 15 , located on the outside of the material analysis chamber  10 . A gear access port  24 , shown in  FIGS. 16 and 17 , provides an opening for the motor  22  to connect to the second gear  18 . The oscillation ring  14  is generally cylindrical in shape and has a top edge that is a vertical displacement contour  26 . 
     This vertical oscillation motion is driven by the first stepper motor  22 , the first and second gears,  16  and  18 , and the oscillator ring  14 . Actuating the first stepper motor  22  forces the second gear  18  and the first gear  16  to rotate, which in turn forces the ring  14  to rotate. As the ring  14  rotates, the wheels  48 , which are mounted at fixed positions on the sieve container wall  32  and seated on the vertical displacement contour  26 , are forced up and down, resulting in a vertical oscillation of the sieve container  31 , along with the plurality of sieves  44 . This vertical oscillation agitates the aggregate mixture sample, causing the particles to separate and then, depending on particle size, drop through the successively mounted sieves  44 , so that sample particles that are smaller than the respective sieve aperture  45  fall from one sieve  44  into a lower sieve  44  until they are captured on a sieve having an aperture size smaller than the particular particle size. Any reasonable rotational speed of the ring  14  causes the sample to separate into particles, however, faster speeds cause the sample to separate faster. There are a number of suitable motors, for example, the RKII stepper motor and driver made by MICROSTEP. 
       FIGS. 5, 6, and 11  show an elevator post  28  that is mounted in the center of the material analysis chamber  10  and extends upward through an opening  52  in the sieve container  31 . As shown in  FIG. 13 , each sieve  44  has a slot  47  approximately in the middle of the sieve  44  and that is sized to fit over the elevator post  28 . In the embodiment shown, the elevator post  28  has an elongate hexagonal shape and the slot  47  a shape that fits over the shaft  28 , such that the sieves  44  are prevented from rotating in a horizontal plane around the elevator post  28 . 
       FIGS. 11 and 15  illustrate a weighing mechanism  49  that is slidably coupled to the elevator post  28 . A second stepper motor  51  drives a threaded rod  52  that extends congruent with a central axis that extends through the elevator post  28  and that is coupled to the weighing mechanism  49 . In the embodiment shown, the weighing mechanism  49  is an elevator disc that contains one or more load cells. A rod access port  53 , shown in  FIGS. 16 and 17 , provides an opening for the motor  51  to connect to the threaded rod  52 . The second stepper motor  51  turns the rod  52  causing the weighing mechanism  49  to rise. As the weighing mechanism  49  reaches each sieve support ring  42 , it lifts each support ring  42  and sieve  44 , stacking the plurality of supports rings  42  and sieves  44  as it travels upward, and calculates the weight of the particle material captured on each sieve  44  by measuring the weight of the stack of sieve rings and sieve plates and subtracting the weight of the sieves  44 , sieve rings  42  and previously weighed particles. The weighing mechanism  49  transmits the information back to the computer control system  90  through an instrumentation feedthrough channel  54 . As the weighing mechanism  49  continues upward, it lifts each successive sieve plate  42  as it travels, transmitting the data to the computer control system  90  as it captures each sieve support ring  42 . 
       FIGS. 16 and 17  illustrate the moisture evacuating unit  60 , which is located outside of the material analysis chamber  10  and is connectable to the sidewall  12  of material analysis chamber  10  by any suitable pipe or tube  62 . The moisture evacuating unit  60  includes a vacuum pump  64  with a moisture vent  65  and a moisture sensor  66 . When the moisture evacuating unit  60  is activated, the pump  64  pulls the moisture from inside the material analysis chamber  10  and past the moisture sensor  66  and out through the moisture vent  65 . The moisture sensor  66  indicates the current level of moisture being drawn from the material analysis chamber  10  and conveys that data to the computer system  90 . Running the moisture evacuating unit  60  until the moisture sensor  66  indicates that there is no moisture in the sieve container  10  leaves a dry sample stored in the material analysis chamber  10 . Also shown is a solenoid valve  67  and a pressure transducer  69  that help to monitor and control the pressure of the moisture evacuating unit  60  if needed. 
     In the embodiment shown, the moisture sensor includes a humidity probe (not shown) within the sensor  66  and a USB feedthrough device  68  that transmits the humidity readings to the computer control system  90 . 
       FIGS. 18-21  illustrate the washing unit  80 , which is provided to clean the chamber after it is used, and includes a water tank  82 , a first water pump  83 , second water pump  84 , and water filter  85  and hosing  86 / 89  to deliver the water to the material analysis chamber  10  and sorting unit  30 . The water tank  82  is filled with clean water (not shown). The first water pump  83  is connected to the water tank  84  and to the water filter  85  by any suitable tubing or hosing  86 , and the water filter  87  is connected to a wide angle nozzle  88  located in the chamber lid  16  by any suitable tubing or hosing  89 . Activating the first water pump  83  delivers water from the water tank  82  to the wide angle nozzle  88  which sprays water throughout the sieve container  31 . The second water pump  84  connects the water tank  82  to a drain pipe  81  in the material analysis chamber  10  and pumps the water out of the material analysis chamber  10  back into the water tank  82 and subsequently, as needed, through the filter  85  to the material analysis chamber  10  for additional washing. 
     Referring again to  FIGS. 1-4  along with  FIG. 22 , the computer system  90  includes an electronics module  92 , a computer  94 , a display unit  96 , and an input unit  98 , and controls the aggregate mixture analysis device  100 . The input unit may be any suitable data entry and control device such as, for example, a keyboard and mouse or a touch screen. In the embodiment shown, the display unit  96  and the computer  94  are each contained within the chassis lid  4 . The computer  94  connects to the electronics module  92  and the electronics module  92  is connected to the first stepper motor  26 , the second stepper motor  48 , the first water pump  84 , the second water pump  86  and the vacuum pump. The connections may be made by any suitable cable, for example, CATV cables. 
     Computer software (not shown) is provided that allows a user to control the aggregate mixture analysis device  100  and calculate and display analysis results. 
       FIGS. 23-26  illustrate a second embodiment of the sorting unit  1000  where the sieve container is a ring cage  108  that is affixed to the first gear  16 . A plurality of rings  208  are affixed to the sides of the ring cage  108 . The rings have a smooth bottom edge  302  and a top edge that has a vertical displacement contour  304  that causes vertical oscillation of the ring cage  108  when rotated. The rings  208  and ring cage  108  are generally cylindrical in shape, with the ring cage  108  narrower at the bottom than at the top and with each successive ring  208  having a slightly greater diameter than the ring  208  immediately beneath it. A sieve  44  sits loosely on top of the each of the rings  208 , each successively lower sieve  44  having a smaller sieve size, i.e., smaller apertures  45 . 
     As in the first embodiment, actuating the first stepper motor  22  drives the second gear  18  which turns the first gear  16 , causing the ring cage  208  to rotate. The sieves  44  are held in position in the horizontal plane by means of the elevator post  306 . As the rings  208  rotate, the vertical displacement contour  304  causes the sieves to oscillate in the vertical plane, thereby agitating the sample, which causes it to break into particles. Depending on particle size, the particles drop down through one or more of the sieves  44 , with each successive sieve  44  having smaller size apertures  45 . 
     It is understood that the embodiments described herein are merely illustrative of the present invention. Variations in the construction of the portable self-cleaning aggregate mixtures analysis device may be contemplated by one skilled in the art without limiting the intended scope of the invention herein disclosed and as defined by the following claims.