Abstract:
An apparatus for agitating materials contained in tubes, including cellular materials and tissues, to release their contents for scientific analysis. The apparatus includes a control enclosure containing a base and a motor, and an interchangeable module that connects to the motor. The interchangeable module includes a tube supporting structure and a rotatable hub connected to one or more strikers positioned to impact the tubes, resulting in agitation of tube contents. Interchangeable modules allow for different shapes and sizes of tubes to be used with a single control enclosure. The apparatus includes a means to measure the rotational velocity of the rotatable hub and the rotational velocity of the strikers. The apparatus further includes protective sleeves for the tubes to prevent breakage, heat build-up from friction and tube caps opening due to rapid impact from strikers.

Description:
BACKGROUND 
     Prior Art 
     The following lists some prior art which presently appears relevant: 
     
       
         
               
             
               
               
               
               
             
           
               
                   
               
               
                 U.S. Patent 
               
             
          
           
               
                   
                 Patent Number 
                 Issue Date 
                 Patentee 
               
               
                   
                   
               
               
                   
                 5,769,538 
                 1998 Jun. 23 
                 Sherman 
               
               
                   
                 6,281,005 
                 2001 Aug. 28 
                 Casal 
               
               
                   
                 7,866,878 
                 2011 Jan. 11 
                 Howe 
               
               
                   
                 7,874,719 
                 2011 Jan. 25 
                 Markle 
               
               
                   
                 5,464,773 
                 1995 Nov. 7 
                 Melendez 
               
               
                   
                   
               
             
          
         
       
     
     Disruption of cells and tissues is a common procedure carried out in biology laboratories to release nucleotides, proteins, virus, small molecules, chemicals, or whole cells for scientific analysis. It is often desirable to disrupt many samples simultaneously in individual tubes or containers to avoid cross contamination and to save time. A striking technology has been described to mechanically disrupt substances in tubes (U.S. Pat. No. 5,769,538 to Sherman). This technology is based on strikers that rotate around a hub or an axis and rapidly contact the tubes with contents inside. The impact of the strikers on the tubes induces turbulent motion of the contents, resulting in mixing, resuspension, homogenization or disruption of the tube contents. 
     The thoroughness of the mixing, resuspension, homogenization or disruption of the substances depends upon the force and frequency that the strikers impact the tube. Tubes made of plastic or another brittle material may crack or break on impact, splattering contents and risking cross-contamination of other tubes. In addition, the cap on the tube may loosen or completely open. The area of impact of the strikers on the tube will also affect the performance of the striking technology. If the tube is struck in a position that is too high or too low, momentum transfer between the striker and the tube may not be sufficient, or the tube may crack. If the height of strikers on the axis/hub is non-adjustable, the striking technology can only be used with one tube size or shape. 
     In addition, the Sherman patent called for an upper and lower plate to hold the tubes in place, limiting the movement of the tubes and thus limiting the agitation of the tube contents. Because of these conditions, a user who wanted to use several different tube sizes would need a separate model specifically designed for each tube type. Multiple models would inconvenience the user with significant extra cost and require extra laboratory space. Keeping extra units in storage to save space would only increase time lost to equipment set up. 
     In the prior art, a motor connected to the hub provides the rotational movement that controls the force and frequency at which the strikers impact the tubes. As the number of tubes in the prior art increases the rotational velocity of the motor will decrease. We have found that the hub will rotate at a faster speed when unimpeded than when the strikers come in contact with tubes. The tubes give resistance which opposes the rotational velocity of the motor. With a greater number of tubes in the prior art&#39;s mixer, each tube will receive fewer or weaker impacts compared to a lesser number of tubes. This results in a reduction of thoroughness of disruption/mixing of tube contents. Inversely if a tube breaks, the resistance felt by the strikers will decrease. This would result in faster rotation of the strikers. This increasing speed would increase the risk of additional tubes breaking. Tubes with samples of larger mass would also create more resistance for the motor, and decreasing the prior art&#39;s effectiveness. The prior art lacks a form of feedback to detect tubes breaking, and control the speed for a desired level of impact. In addition, the prior art has no way to compensate for the mass or viscosity of the samples in the tubes 
     We have found that an issue experienced by the prior art was a build-up of heat within the tubes due to friction from direct impacts by the strikers. Heat rising within samples can create adverse conditions for some methods of scientific analysis. Additionally, we have found that impacts on tubes result in a very loud running volume. The user may experience an uncomfortable level of noise, often times too loud to hold a normal conversation while in close proximity. Many users preferred to be in another room while the units ran. Covering the unit would reduce the noise but doing this would exacerbate heat build-up by restricting or limiting ambient air. 
     It would be desirable to have a device to protect the tubes while they receive maximum force from the strikers for effective mixing, resuspension, homogenization or disruption. In addition, it would be desirable for the striking technology to conveniently allow for different sizes, shapes and quantities of tubes while protecting the tubes from breaking and ensuring that each tube receives the desired striking impact at the optimal position regardless of the number of tubes present in the unit. It would also be desirable to reduce both the heat build-up on tubes, and the loud running noise. 
     Advantages 
     Accordingly, several advantages of one or more aspects of the current invention are as follows: protection of the sample tube from the impacts, thus allowing more frequent impacts and impacts of greater magnitude, limitation of caps loosening, reduction of heat build-up, reduction of noise, interchangeability of sample tubes, consistent performance, automatic shut-off in the case of a tube failure. Further advantages of one or more aspects of the current invention will become apparent from a consideration of the drawings and the detailed disclosure. 
     Summary 
     One or more aspects of the present invention provide a protective sleeve with a space allotted for a tube. The energy from the impact of the strikers onto the protective sleeve will be transferred to the tube over a larger surface area, allowing the tube to be impacted without sustaining damage or having the cap loosened or opened. In an embodiment, the open base and material composition allow for the sleeve to deform upon impact, increasing the momentum transfer from the striker to the tube. The protective sleeve will protect tubes from impacting strikers inside of an agitation apparatus. Additionally this extra layer of protection will reduce heat build-up in the tubes due to friction from impacting strikers. 
     Another aspect of the present invention provides a removable module able to hold a set number of tubes. In an embodiment, the module contains a rotatable hub shaft with strikers. The module fits inside of a base unit or control enclosure containing a motor. The hub shaft in the module attaches to the motor in the base unit, providing rotational movement to spin the strikers around the rotatable hub and strike the tubes. Multiple interchangeable modules accommodating different sized tubes or placement configurations can be used with a single control enclosure. The control enclosure uses a sensor to identify the module that is inserted and adjusts the operational parameters for the type of tubes used in said module. 
     Having multiple interchangeable modules with a single control enclosure is convenient and cost effective compared to having several standalone apparatuses. In an embodiment, the module, located inside the control enclosure, provides a layer of sound isolation close to the source of the noise. The control enclosure provides a second layer of sound isolation, thereby reducing the level of noise observed by the user. 
     Another aspect of the present invention provides a method for adjusting the magnitude or frequency of the impacts, based upon the load, which includes the number of tubes and the mass of the content in them. Additionally the invention has the ability to sense when a tube has broken and stop the apparatus from running. 
    
    
     
       DRAWINGS 
       Figures 
         FIG. 1   a  shows a diametric view, in accordance with one embodiment, of a protective sleeve for a tube, a detachable module containing a striking mechanism and a control enclosure for retaining and controlling the module. Hatched lines show cut away portions for a clearer illustration of the internal geometry. 
         FIG. 1   b  shows a diametric view of the module. Hatched lines show cut away portions for a clearer illustration of the internal geometry. 
         FIG. 1   c  shows the module in its open configuration, and loaded with eight protective sleeves. 
         FIG. 1   d  shows the module inserted or installed in the base unit. Hatched lines show cut away portions for a clearer illustration of the internal geometry. 
         FIG. 1   e  shows a side cut away view of the module inserted into the base unit. Hatched lines show cut away portions for a clearer illustration of the internal geometry. 
         FIG. 2   a  shows an isometric view of the protective sleeve for a tube, with hidden lines shown dotted, in accordance with one embodiment. 
         FIG. 2   b  shows a top view of the protective sleeve in accordance with one embodiment. 
         FIG. 2   c  shows a cross sectional view of the protective sleeve in accordance with one embodiment. 
         FIG. 3   a  shows a general flow chart for the method in which the electronics control the speed of the strikers. 
         FIGS. 3   b  to  3   d  show more particularized flow charts for the method in which the electronics control the speed of the strikers. 
     
    
    
     
       
         
               
             
               
               
             
           
               
                   
               
               
                 Drawings - List of Reference Numerals 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 10 
                 Control enclosure 
               
               
                 12 
                 Tube 
               
               
                 14 
                 User controls 
               
               
                 16 
                 Outer housing 
               
               
                 18 
                 Outer lid 
               
               
                 20 
                 Motor mounting plate 
               
               
                 22 
                 Variable speed electric motor 
               
               
                 24 
                 Motor shaft 
               
               
                 26 
                 Lower disconnecting coupling half 
               
               
                 28 
                 Bottom standoffs 
               
               
                 30 
                 Guide hole 
               
               
                 32 
                 Guide pin 
               
               
                 34 
                 Upper standoffs 
               
               
                 36 
                 Module 
               
               
                 38 
                 Sleeve holding plate 
               
               
                 40 
                 Cylindrically cut holes 
               
               
                 42 
                 Protective sleeve 
               
               
                 44 
                 Flange 
               
               
                 46 
                 Tubular main cylinder 
               
               
                 48 
                 Tube retaining platform 
               
               
                 50 
                 Cap sleeve 
               
               
                 52 
                 Flanged bearing 
               
               
                 54 
                 Rotatable hub shaft 
               
               
                 55 
                 Upper disconnecting coupling half 
               
               
                 56 
                 Rotatable hub 
               
               
                 58 
                 Shoulder bolts 
               
               
                 60 
                 Pendulum arm 
               
               
                 62 
                 Strikers 
               
               
                 64 
                 Module catch basin 
               
               
                 66 
                 Coupling access port 
               
               
                 68 
                 Module lid 
               
               
                 70 
                 Upper shroud 
               
               
                 72 
                 Lid plate 
               
               
                 74 
                 Retaining arms 
               
               
                 76 
                 Thin shaft 
               
               
                 78 
                 Ball end 
               
               
                 80 
                 Slotted hole 
               
               
                 81 
                 Handle 
               
               
                 82 
                 Retaining plate 
               
               
                 84 
                 Module cavity 
               
               
                 88 
                 Module locking mechanism 
               
               
                 90 
                 Upper standoff grooves 
               
               
                 92 
                 Module sensor 
               
               
                 94 
                 Speed sensor 
               
               
                 96 
                 User input settings 
               
               
                 98 
                 Sensing Mode 
               
               
                 100 
                 Run Mode 
               
               
                 102 
                 Steady state mode 
               
               
                   
               
             
          
         
       
     
     DETAILED DESCRIPTION 
     First Embodiment 
     FIGS.  1   a - d ,  2   a - c  and  3   a - b    
     One embodiment of the present invention is illustrated in  FIG. 1   a - d ,  2   a - c  and  3   a - b .  FIG. 1   a  shows an instrument or control enclosure  10  for impacting tubes  12 ; causing frequent oscillations and energetic movement for said tubes  12 . The control enclosure  10  refers to several elements acting as a stationary base. The control enclosure  10 , contains the electronics (not shown), and internal components. The main body of the control enclosure  10  is an outer housing  16 . The front of the outer housing  16  has user controls or user interface  14 . The top of the outer housing  16  has an outer lid or cover  18 , which splits opening from the center and hinged on the top of the outer housing&#39;s  16  right and left sides. 
     Mounted to the inside of the outer housing  16  on the bottom face is a motor mounting plate  20 . A variable speed electric motor  22  is affixed to the center of the motor mounting plate  20 . A drive shaft  24  projects upward to a lower disconnecting coupling half  26 . Extending vertically upward from the motor mounting plate  20  are four bottom standoffs or supports  28 . 
     Each of the bottom standoffs  28  contain a guide hole  30  on their top face which aligns with a pin  32  on the underside of a set of four upper standoffs  34 . The upper standoffs  34  act to guide a removable assembly or module  36  into the control enclosure  10 . 
     In the module  36 , affixed to the other end of the upper standoffs  34 , is a sleeve holding plate  38 . In this embodiment, the sleeve holding plate  38  has multiple cylindrically cut holes  40  in its surface. Several cylindrically cut holes  40  are not shown due to the cut away view. 
     Within each cylindrically cut hole  40  hangs a removable protective casing or protective sleeve  42 . In this embodiment, shown in  FIGS. 1   a  and  2   a - c , the protective sleeve  42  is one continuous piece of plastic or other strong and flexible material. The protective sleeve  42  is comprised of several features or parts. The protective sleeve  42  hangs by a flange or lip  44  which is larger in diameter than the cylindrically cut hole  40 . The protective sleeve  42  has a main tubular cylinder  46  affixed to the flange  44 . The main tubular cylinder  46  extends vertically down through the cylindrically cut hole  40 . The main tubular cylinder  46  is smaller in diameter than the cylindrically cut hole  40 . At the bottom of the main tubular cylinder  46  is an affixed flexible tube retaining platform  48  Sitting on the tube retaining platform  48  rests the bottom of a tube  12 . The tube retaining platform  48  functions to hold the tube  12  in an optimal position within the protective sleeve  42 . In this embodiment, the tube retaining platform  48  is comprised of three thin spokes; shown in  FIG. 2   a - c . This geometry allows the tube retaining platform  48  to remain flexible. When the tubular cylinder  46  is impacted, it will deform from a circular opening to an ellipse. The spokes comprising the tube retaining platform  48  add very little rigidity to the tubular cylinder  46  since they are thin and not in line with each other; easily bending to allow the tubular cylinder  46  to be deformed. From the flange  44  extends upward a vertical cylindrical wall, or cap sleeve  50 . The cap sleeve  50  extends beyond the height of the tube  12 . The protective sleeve  42  fits loosely in the cylindrically cut hole  40 , so the protective sleeve  42  is able to rock or pivot within the cylindrically cut hole  40 . 
     The following refers to  FIG. 1   b , showing the module  36  in more detail. Centered and bolted to the underside of the sleeve holding plate  38 , is a flanged bearing  52 . A rotatable hub shaft  54  within the flanged bearing  52  extends vertically downward, ending in an upper disconnecting coupling half  55 . Located at a specific distance down from the sleeve holding plate  38  is a rotatable hub  56  fixed to the rotatable hub shaft  54 . In this embodiment the rotatable hub  56  has five positions for shoulder bolts or pins  58 . The shoulder bolts  58  are on a bolt circle concentric with the rotatable hub shaft  54 . Each shoulder bolt  58  pins a pendulum arm  60  which can rotate around the axis of each attached shoulder bolt  58 . Fastened to the end of each pendulum arm  60  is a striker, hammer, or weighted mass  62 . As the hub  56  rotates, the strikers  62  pivot to their fully extended form, and have an intersecting path with the bottom of the protective sleeves  42 . The distance between the rotatable hub  56  and the sleeve holding plate  38  is such that the area of impact of the strikers  62  on the tube  12  or the protective sleeve  42  results in sufficient momentum transfer for effective mixing of tube contents. The distance between the rotatable hub  56  and the sleeve holding plate  38  will vary depending upon the size and shape of the tube  12  or protective sleeve  42  that is intended for use in the module  36 . If different sized tubes  12  are required by the user, a different module  36  may be used in the control enclosure  10 . 
     Enclosing the module  36  and extending down from the tube holding plate  38 , is a module catch basin  64 . The module catch basin  64  envelopes the lower half of the module  36  and has an opening or coupling access port  66  centered at its bottom to expose the upper disconnecting coupling half  55 . Enclosing the upper half of the module  36  is a module lid  68 , shown detached in  FIG. 1   c . The module lid  68  is comprised of several parts, shown in  FIG. 1   b . Radially surrounding the upper half of the module  36  is an upper shroud  70 . The bottom edge of the upper shroud  70  fits into the top of the module catch basin  64 . A lid plate  72  retains the upper shroud  70  in place. From the underside of the lid plate  72  extends four vertically hanging retaining arms or locking mechanism  74 . The retaining arms  74  have a thin shaft  76  which joins to a larger ball end  78 . Each retaining arm  74  extends through a slotted hole  80  located along the perimeter of the sleeve holding plate  38 . Using a handle  81  on the top of the lid plate  72 , a user can turn or rotate the module lid  68  clockwise (with respect to the stationary sleeve holding plate  38 ) to lock said module lid  68  in place. Fastened to the underside of the lid plate  72 , above the protective sleeves  42 , is a hardened contact retaining plate  82 . The retaining plate  82  acts as a hard stop to limit the travel of the protective sleeves  42 , and prevents the protective sleeves  42  from ejecting from the cylindrically cut holes  40 . 
     Referring back to  FIG. 1   a  shows the control enclosure  10  has a void, space, or module cavity  84  for the module  36  to be inserted, or installed. When the module  36  is inserted into the control enclosure&#39;s  10  module cavity  84  the pins  32  on the upper standoffs  34  will align with the holes  30  in the bottom standoffs  28 , guiding the module  36  into place. A module locking mechanism  88  will secure the module  36  in place by rotating clockwise around its central axis. The module locking mechanism  88  will interlock with grooves on the upper standoffs  90 . When the module  36  is fully inserted into the control enclosure  10  the two disconnecting coupling halves  26  &amp;  55  will interlock together, shown in  FIG. 1   e . These disconnecting couplings  26  &amp;  55  will mate to form a mechanical connection between the hub shaft  24  and the motor shaft  54 .  FIG. 1   d  and  1   e  show the module  36  installed in the control enclosure  10 . 
     Referring back to  FIG. 1   a , a module sensor  92  affixed to the module cavity  84  will detect the presence of the module  36 , and the module&#39;s version. A hub sensor or speed sensor  94  measures the speed of the rotating hub  56  and strikers  62 , as the unit runs. In this embodiment, the speed sensor  94  is mounted to the top of the motor  22 ; shown in  FIG. 1   a.    
     Operation 
     A first embodiment of the control enclosure  10  allows for interchangeable modules to be installed. A user chooses a module such as the module  36  shown in this embodiment. Opening the outer lid  18  the user lowers the module  36  into the module cavity  84 , aligning the upper standoff pins  32  with the lower standoffs  28 . When the module  36  is in its lowest seated position, the coupling halves  26  &amp;  55  will mate, forming a physical connection from the motor shaft  24  to the hub shaft  54 .  FIGS. 1   d  and  1   e  show the module  36  installed in the control enclosure  10 . 
     The module sensor  92 , shown in  FIG. 1   a , will detect the type of module  36  installed and confirm that it is aligned correctly within the module cavity  84 . The module sensor  92  uses a radio frequency identification tag (not shown), magnets (not shown) or other sensor flags (not shown) installed on the module, which are well known to a person of ordinary skill in the art. The control enclosure  10  will then secure the module  36  in place by rotating the module locking mechanism  88 . 
     Using the handle  81  the user then rotates the module lid  68  and lifts up from the module  36 , revealing the sleeve holding plate  38 . An open module  36  is shown in  FIG. 1   c . The user then inserts tubes  12  into the protective sleeves  42 . Extra protective sleeves  42 , not in use, may be lifted out and removed from the module  36 . The module lid  68  is then secured by aligning the retaining arms  74  with the slotted holes  80  in the sleeve holding plate  38 , and rotating clockwise. Shown in  FIG. 1   d , the outer lid  18  is then closed. 
     The action of the tubes&#39;  12  agitation is described here. When the motor  22  is powered by the electronics (not shown, but known to a person of ordinary skill in the art), it rotates the attached hub  56 . This spinning will extend the pendulum arms  60  and strikers  62 . The extended pendulum arms  60  impact the side of the tubular main cylinder  46 . From this impact the protective sleeve  42  tilts away from the spinning strikers  62 . 
     The control enclosure  10  creates an oscillating motion for the tubes  12 . The action of tube oscillations is achieved from the frequent impacts on the protective sleeves  42 . Upon impact each protective sleeve  42  pivots at the cylindrically cut hole  40 , tilting the bottom of the protective sleeve  42  away from the strikers  62 . Space between the cylindrically cut hole  40  and the main tubular cylinder  46  allows for this rocking motion. The protective sleeve  42  rocks away or recoils from the strikers  62  until its movement is stopped by the cap sleeve  50  coming into contact with the stationary retaining plate  82 . The retaining plate  82  acts as a hard stop to restrict unnecessary excess movement of the protective sleeves  42 , and prevent the protective sleeve  42  and its contained tube  12  from ejecting themselves from the sleeve holding plate  38 . 
     The protective sleeve  42  will rebound from the retaining plate  82  and return to its vertically oriented position. As the protective sleeve  42  rights itself vertically it will enter the impact zone of the strikers  62  again. The tube  12  contained within the protective sleeve  42  rapidly and forcefully shakes as the protective sleeve  42  is repeatedly struck by the strikers  62 , causing the protective sleeve  42  to recoil then rebound from the retaining plate  82 . 
     The strikers  62  also rebound after impacting the protective sleeve  42 . Each striker  62  attached to a pendulum arm  60  pivots out of the impact zone after making contact with the protective sleeve  42 . This recoiling action serves to extend the life of the internal components as well as to prevent the pendulum arms  60  from jamming, causing motor  22  seizures. As the hub  56  continues to spin the pendulum arms  60  will return to their out stretched normal position. In this outstretched position, the striker  62  will impact another protective sleeve  42  and repeat the cycle. 
     In this embodiment, the rotational velocity of the motor shaft  24  is controlled by applying power to the motor  22  by means of pulse width modulation, which is well known in the art. To change the rotational velocity of the motor shaft  24 , the control enclosure  10  changes the duty cycle of voltage pulses applied to the motor  22 . The control enclosure provides an adjusted electronic control to the motor. An increase in duty cycle will increase the rotational velocity of the motor shaft  24 , while a decrease in duty cycle will decrease the rotational velocity of the motor shaft  24 . 
     The method in which the control enclosure applies and controls the motor  22  is described in  FIG. 3   a . In this embodiment there are three modes: sensing mode ( 98 ), run mode ( 100 ) and steady state mode ( 102 ), which are each expanded in  FIGS. 3   b  to  3   d .  FIG. 1   a  shows the physical components (numbers  10 - 94 ) while  FIG. 3   a  to  FIG. 3   d  (numbers  96 - 102 ) shows the process or method in which the control enclosure  10  controls the strikers  62 . To begin, the user will select a desired power level and duration  96  with the user controls  14 . The control enclosure  10  utilizes the illustrated method or process in  FIG. 3   a  to achieve consistent striking force and frequency matching the user&#39;s desired power level  96 . The control enclosure  10  will increase or decrease the RPM (revolutions per minute) of the strikers  62  based on the number of tubes  12  in the module  36  and the user&#39;s selected power level. 
     To obtain the number of tubes in the module  36  the control enclosure  10  will begin running in sensing mode  98 , shown in  FIG. 3   b . Sensing mode  98  begins with the motor  22  being given a predetermined test power  98   a . This predetermined test power is independent from the user&#39;s desired power level  96 . This test power rotates the motor shaft  24  and the attached hub  56  for a predetermined amount of time. During this time, the speed sensor  94  detects the hub&#39;s RPM  98   b . Depending upon the amount of tubes  12  in the module  36  the RPM of the strikers  62  will vary for the predetermined test power  98   a  given to the motor  22 . Each possible number of tubes  12  corresponds with a known RPM range. The control enclosure  10  compares the detected RPM with these known RPM ranges. This step in the method  98   c  determines the amount of tubes  12  in the module  36 . 
     Using the determined number of tubes  98   c  and the user&#39;s selected power level  96 , the control enclosure  10  performs a mathematical calculation and selects the necessary target RPM for the strikers  62  to achieve an appropriate and consistent frequency of tube oscillations  98   d , which becomes the set point for the control enclosure  10 . Strikers  62  with rotational velocity matching the RPM of this set point  98   d  will give consistent results for each user selected power level  96 . 
     The control enclosure  10  then enters run mode  100 , shown in  FIG. 3   c . During run mode  100  the control enclosure  10  applies power to the motor  22  which drives the hub  56  and strikers  100   a . On a specified time interval the control enclosure  10  samples the RPM of the hub  56  using the speed sensor  100   b , which is part of the sensing circuit (not shown). The observed RPM is compared to the necessary target RPM  100   c . If the observed RPM is less than the necessary target RPM  100   d  the control enclosure  10  will increase the RPM of the hub  100   e . If the observed RPM is greater than the necessary target RPM  100   f  the RPM of the hub will be decreased  100   g . Once the observed RPM is acceptably close to the necessary target RPM  100   h , the control enclosure will keep the RPM of the hub  56  constant  100   i , and the control enclosure  10  will move on to Steady State Mode  102 . 
     During Steady State Mode  102 , shown in  FIG. 3   d , at each specified time interval, the control enclosure  10  samples the RPM of the hub using the speed sensor  102   a . The observed RPM is compared to the necessary target RPM  102   b . If the observed RPM is less than the necessary target RPM  102   c  the control enclosure  10  will apply a greater voltage  102   d . If the observed RPM is equal to the necessary target RPM  102   e  the control enclosure will keep the RPM of the hub  56  constant  102   f . If the observed RPM is greater than the necessary target RPM  102   g  by less than a specified percentage the RPM of the hub  56  will be decreased  102   h . If the observed RPM is greater than the necessary target RPM by over a specified percentage  102   i , a tube  12  failure is indicated  102   j . This may happen if a tube  12  or protective sleeve  42  is ejected from the cylindrically cut hole  40  or broken. At this point the control enclosure  10  will stop the strikers from rotating and alert the user to check the module for a potential fault  102   j.    
     Description and Operation of Alternative Embodiments 
     The following additional embodiments are described, without limiting the scope of the invention from further variations that can be easily determined. 
     There could be other methods of controlling the motor speed, including, but not limited to pulse width modulation, frequency of pulses, voltage control, and/or electrical current, which are all well known in the art. 
     An electronic sensing circuit, possibly with an optical sensor or magnetic sensor or capacitive sensor could be used to determine the movement of the rotatable hub or the velocity of the individual strikers or the magnitude or velocity of the rebound of the strikers after they impact the tubes. Alternatively, the sensing circuit could monitor the electrical emissions or radio frequency emissions from the motor. Any number of feedback controls could compensate for the velocity of the hub or the speed of the individual strikers or the rebound characteristics of the strikers. 
     The base control enclosure could have a magnetic coupling in place of the mating disconnecting coupling halves  26  &amp;  55  (shown in  FIG. 1   a  &amp;  1   b  respectively), or multiple bearings on the rotatable hub shaft  54 . 
     The design of a control enclosure  10  which controls a detachable module lends itself to allow for multiple module configurations. Modules can be designed for various tube types and geometries. These modules could be designed to use a smaller or larger tube type having an adjusted hub height, smaller or larger strikers, and smaller or larger cylindrically cut holes. A module may be designed for many tubes to be processed at once. Modules can have varying patterns or layouts for tube locations. A module may have more cylindrically cut holes and strikers installed on its hub, relative to the shown embodiment. More strikers will be present if a higher quantity range of tubes are desired. The strikers&#39; quantity, length, mass, shape and placement (altering the impact location) can be preset for each module optimizing their use with a particular tube geometry. These variances in the design of each module would exist to both optimize results and simplify operation for the user. The user would simply choose an appropriate module for the desired operation. 
     The protective sleeve can have multiple versions and geometries to accommodate different tube sizes and types. A protective sleeve may account for many, if not all, tube geometries. The defining characteristics of the protective sleeve include a casing whose walls surround and encompass a tube held within, providing protection for the tube from direct impact with the strikers and additionally have a mechanism for mounting the protective sleeve within the impact zone of the strikers, while still allowing for the necessary range of movement for said protective sleeve. 
     There may be additional embodiments of the tube retaining platform. For example, the tube retaining platform may have spokes or projections which extend partly or completely through the bottom opening, a ring which acts as a shelf for the tube to sit, or solid wall, all of which would be intended to prevent the tube from falling through a hole. Other variations could include one or more varieties of caps to cover the top of the tube, or additional mounting mechanisms intended to hold the sleeve in place instead of utilizing a shelf. 
     The threshold in  102   i  can be varied to adjust the faulting sensitivity from module to module or changed based on the determined number of tubes. 
     Another embodiment uses a sensing circuit to measure the instantaneous velocity of the strikers. The mathematical calculation for the necessary target RPM could use a look up table or a mathematical formula. The table or formula be used to compensate for the content in the tubes, thereby having the strikers impact with greater force if the content in the tube has more mass or exhibits more resistance to the impacts. 
     In another embodiment the removable module performs the mathematical calculation for the necessary target RPM. 
     Another embodiment uses a sensing circuit to measure the rotational velocity of the hub or count the rotations of the hub in a given time period, and compensate for the load in the unit. The hub could be driven at a greater speed and/or with more torque and/or more time to compensate for more tubes and/or more mass in the tubes. Additionally a user could directly select a particular rotational velocity. 
     CONCLUSION, RAMIFICATIONS AND SCOPE 
     Accordingly, the reader will see that at least one embodiment of the described agitation apparatus can be used to provide protection for tubes allowing for tube contents to be agitated with greater force, can lessen the risk of tube caps loosening or opening and can limit heat build-up and excess noise. In addition, at least one embodiment of the described agitation apparatus can use interchangeable modules to allow for the use of a variety of tube types, and feedback sensors to control consistency of the agitation of tube contents per user setting, and to automatically stop agitation in the case of tube failure. 
     While the above description contains many specificities, these should not be construed as limitations on the scope of the embodiments, but rather as providing illustrations of some of several embodiments. The scope of the embodiments should be determined by the appended claims and their legal equivalent, rather than by the examples given.