Abstract:
The disclosed method allows for a septic tank made of a pourable castable material to be constructed with a single continuous pour to create a septic tank with no seams. This method may be practiced at the site of septic tank installation, minimizing the stress on the septic tank that result from being transported to the installation site.

Description:
PRIORITY/CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to Provisional Patent Application No. U.S. 61/955,149 entitled “Method for Construction of Concrete Septic Tanks” by Harry Cormier filed on Mar. 18, 2014. That application is incorporated by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    A septic tank  1000  is a common item in modern houses that are not connected to large sewerage networks. These septic tanks  1000  need to be able to accommodate and process the volume of waste water generated by users in the house. 
         [0003]    Septic tanks  1000  connect to the waste water source via an inlet pipe that enters the septic tank  1000  through an inlet opening  710 . Typically there is a baffle  520  (dividing wall) inside the septic tank  1000  that separates the septic tank  1000  into two chambers. The baffle  520  may have a baffle aperture  525  to facilitate water flow between the chambers of the septic tank  1000 . The first chamber  590  is where the waste water initially enters, where the solid materials eventually settles to the bottom to be broken down through various means. The remaining waste water flows into the second chamber  595 , where further waste eventually settles out before the waste water is discharged though the outlet opening  750  to the outlet pipe into a leech field or other system. 
         [0004]    Septic tanks  1000  may be installed above or below the ground. When a septic tank  1000  is installed underground, soil is excavated to make a pit large enough to accommodate the septic tank  1000 . The septic tank  1000  is placed in the pit, connected to the waste water feed source, connected to a discharge system, and covered with soil. 
         [0005]    Septic tanks  1000  may be made from various materials, including but not limited to steel, plastic, fiberglass, high density polyethylene, or concrete. Concrete septic tanks  1000  have certain advantages over septic tanks  1000  made from other materials. Concrete septic tanks  1000  get stronger over time as the concrete cures. Concrete septic tanks  1000  are not as buoyant as some other septic tank  1000  materials, reducing the need to prepare a site for septic tank  1000  installation. Concrete does not have any known toxic properties. Concrete septic tanks  1000  are also resistant to any damage that may occur during backfill. 
       SUMMARY 
       [0006]    The disclosed invention relates to a method for constructing a concrete septic tank. The method will allow for standard and customized concrete septic tanks  1000  to be built as the project requires. Concrete septic tanks  1000  of different volumes, numbers of openings, baffles, opening locations, and other details may be accounted for using the method disclosed herein. 
         [0007]    The method involves preparing the area to construct the septic tank  1000 . A series of frames are placed in the area and are secured. Once the frames are secured, concrete is poured in such a manner that the frame makes the resulting concrete structure becomes a septic tank  1000 . Other embodiments utilizing molds accomplishing the same effect. 
         [0008]    One of the advantages of this method is the resulting tank is made of a single piece of concrete that can further be sealed with a sealing pour to form one concrete unit. Once the septic tank  1000  is created, it may be used as a normal septic tank  1000 . 
     
    
     
       BRIEF DESCRIPTION OF FIGURES 
         [0009]      FIG. 1  is a flowchart showing an exemplary embodiment of a Frame Pour method  100  in an exemplary embodiment. 
           [0010]      FIG. 2  is a flowchart showing an exemplary embodiment of a Mold Pour method  200  in an exemplary embodiment. 
           [0011]      FIG. 3  is a flowchart showing an exemplary embodiment of a Lid Pour method  300  in an exemplary embodiment. 
           [0012]      FIG. 4  is a perspective drawing of the foundation frame  450 , sidewall frame  455 , baffle frame  460 , headwall frame  475 , blocking mold  465 , and connector  480  in an exemplary embodiment. 
           [0013]      FIGS. 5   a - e  show the process of pouring the castable material in an exemplary embodiment. 
           [0014]      FIG. 6  shows the septic tank  1000  formed in  FIG. 5   e  with the sidewall frame  455 , blocking mold  465 , and connectors  480  removed in an exemplary embodiment. 
           [0015]      FIG. 7  shows the flow of waste water in the resulting septic tank  1000  in an exemplary embodiment. 
           [0016]      FIG. 8   a  is a top down view of the object of  FIG. 4  in a pit when a secondary frame  910  is not installed before the concrete pour in an exemplary embodiment. 
           [0017]      FIG. 8   b  is a top down view of the septic tank formed after the concrete pour with the frames removed when a secondary frame  910  is not installed in an exemplary embodiment. 
           [0018]      FIG. 9   a  is a top down view of the object of  FIG. 4  in a pit when a secondary frame  910  is installed before the concrete pour in an exemplary embodiment. 
           [0019]      FIG. 9   b  is a top down view of the septic tank formed after the concrete pour with the frames and secondary frame  910  are removed in an exemplary embodiment. 
           [0020]      FIG. 10  is a perspective drawing of the septic tank  1000  with the lid  1010  placed above it in an exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    The exemplary embodiment will describe an in ground concrete septic tank  1000  formed at the installation location as opposed to being transported to the installation location. However, it is understood that the same process may be adapted to above ground concrete septic tanks  1000  or ones formed to be transport later as needed. Further, while concrete is discussed, it may apply to any castable material that may be poured to create structures. 
         [0022]    The requirements of the septic tank  1000  determine the steps to be taken. First the size of the septic tank  1000  needs to be established. This may be based on multiple factors, including, but not limited to, number of possible users of the septic tank. Once the size of the septic tank  1000  is determined, then an area is excavated, forming a pit with a pit bottom  515  and pit walls  510 , to accommodate the septic tank  1000 . A series of frames are then erected within the pit to control the pouring of the concrete. The dimensions of these frames will be determined by how large a septic tank  1000  is needed to accomplish the intended purpose of the septic tank  1000 .  FIG. 4  provides a visual representation of how such a series of frames would look in an exemplary embodiment when outside of the pit. 
         [0023]    Frame Guided Method For Creation of Septic Tank 
         [0024]    This method is disclosed in  FIG. 1  creates a frame poured tank  100 . A pit is excavated per the process  105  to accommodate the resulting septic tank  1000 . A foundation frame  450  is installed per the process  110  on the pit bottom  515 . This foundation frame  450  will rest on supports, known in the trade as a floating form  530 , keeping the foundation frame  450  above the surface of the pit bottom  515 . 
         [0025]    Once the foundation frame  450  is installed per the process  110 , the next step per the process  115  involves the installation of the sidewall frames  455 , baffle frames  460 , and headwall frames  475  adjacent to, if not connected to, the surface of the foundation frame  450 . The sidewall frames  455  and headwall frames  475  together are referred to as a primary frame. The sidewall frames  455  are situated at the edge of the foundation frame  450  for a substantial length of the sides of the foundation frame  450 . The sidewall frames  455  end at the location where the baffle frames  460  are to be installed. The headwall frames  475  are at the distal ends of the foundation frame  450 . The location of the baffle frames  460  may be at any position, but is typically near the mid-point between the headwall frames  475 . The baffle frames  460  run parallel to the headwall frames  475 . In the exemplary embodiment, the sidewall frames  455 , headwall frames  475 , and baffle frames  460  couple to the foundation frame  450  at a right angle by any means known to those skilled in the art. 
         [0026]    In the exemplary embodiment, there will be a space between the two baffle frames  460 . A blocking mold  465  will be located on the foundation frame  450  that will occupy a portion the space between the two baffle frames  460 . The blocking mold  465  will be sized to create the necessary baffle aperture  525  in the resulting sceptic tank  1000 . The area defined between the two baffle frames  460  will be the area the baffle  520  will form within. The baffle  520  will not completely occupy the space between the baffle frames  460  because the blocking mold  465  will prevent liquid castable material from occupying the area of the baffle aperture  525 . 
         [0027]    In an exemplary embodiment, there are two ways to define the outer edges of the septic tank  1000 . There is a single frame method where the outside of the septic tank  1000  is defined by the coupled sidewall frames  455  and headwall frames  475  with respect to the pit wall  510 . There is also the double frame method where the outer edge of the septic tank  1000  is defined by the sidewall frame  455  and headwall frame  475  with respect to a secondary frame  910 . Both will be explained in turn. 
         [0028]    Frame Guided Method-Single Frame Method 
         [0029]    Using the single frame method, there will be no need for a secondary frame  910  per the process  120 . The sidewall frames  455  and the headwall frames  475  are positioned to allow for concrete to be poured in the area between the sidewall frames  455  and the pit wall  510  along with the headwall frames  475  and the the pit wall  510 , while at the same time allowing the concrete to flow beneath the foundation frame  450 . The walls of the septic tank  1000  form between the space defined by the sidewall frames  455  and headwall frames  475  versus the pit walls  510 .  FIG. 8   a  shows a top down view of how this embodiment would look before the concrete is poured.  FIG. 8   b  shows a top down view of how this embodiment would look after the concrete is poured. 
         [0030]    Frame Guided Method-Double Frame Method 
         [0031]    Using the double frame method, a secondary frame  910  is used per the process  120 . To use a double frame method, a sidewall frame  455  and headwall frames  475  are used as previously disclosed in the single frame method. A secondary frame  910  is then erected per the process  125  between the combined sidewall frames  455  and headwall frames  475  versus the pit walls  510 . This allows the concrete to be poured as previously disclosed in the single frame method, but not to interact with the pit walls  510  directly. The formation of the sides of the septic tank  1000  as an integrated unit is achieved as in the single frame method, but the concrete flow is more carefully controlled. This also allows for builders to interface with the septic tank  1000  before it is covered without excavating more soil. This method may also be used to create an above ground septic tank  1000 .  FIG. 9   a  shows a top down view of how this embodiment would look before the concrete is poured.  FIG. 9   b  shows a top down view of how this embodiment would look after the concrete is poured. 
         [0032]    Frame Guided Method-Openings 
         [0033]    Septic tanks  1000  typically have at least one inlet opening  710  and one outlet opening  750 . If the inlet openings  710  and outlet openings  750  are to be on the sides of the septic tank  1000  per the process  130 , then the sidewall frame  455  (and secondary frame  910  as applicable) may further comprise projections  480  for the concrete to flow around so that the inlet openings  710  and outlet openings  750  may be maintained for connections during the pour. In an exemplary embodiment utilizing the single frame method, a removable projection  480  will be installed per the process  140  out of the headwall frame  475  where the inlet openings  710  and outlet openings  750  are required. This projection  480  would extend far enough to make sure no concrete blocks the inlet openings  710  and outlet openings  750  when the concrete cures. If the double frame method is used, then the projection  480  would connect the sidewall frame  455  or headwall frame  475  and the secondary frame  910  at the desired inlet opening  710  location and outlet opening  750  per the process  145 . Once the concrete has been poured per the process  150  and sufficiently hardened, the projections  480  are to be removed to show the openings. 
         [0034]    In an alternative embodiment, the actual inlet pipes and outlet pipes to be used by the septic tank  1000  may be used to form the inlet openings  710  and outlet openings  750  in the place of projections  480 . The pipes may be installed, and the sidewall frame  455  or headwall frame  475  may be constructed around them. When the concrete is poured, the concrete will flow around the pipes, creating the openings necessary in the septic tank  1000  for access. 
         [0035]    If the inlet openings  710  and outlet openings  750  will be on the top surface of the septic tanks  1000 , then no inlet openings  710  and outlet openings  750  will be needed in the sidewalls  1040  or headwalls  1030 . The inlet openings  710  and outlet openings  750  may be part of the lid  1010 , which will be discussed below. In an exemplary embodiment, the inlet opening  710  is higher than the outlet opening  750 . However, any alternate orientation that facilitates the proper flow of waste water in the septic tank  1000  will not conflict with the basic scope of this invention. 
         [0036]    The pipes used to transport the waste water are four inches pipes in an exemplary embodiment. However, pipes of different sizes may be used without departing from the spirit of this invention. 
         [0037]    Frame Guided Method-Pour 
         [0038]    Once the foundation frames  450 , sidewall frames  455 , baffle frames  460 , and headwall frames  475  have been erected and the projections  480  have been made (if applicable), then the concrete is poured per the process  150 . 
         [0039]    In the exemplary embodiments, the concrete is poured outside of the sidewall frames  455  and headwall frames  475  to form the sidewalls  1040  and headwalls  1030 , and the excess concrete seeps beneath the foundation frame  450  to form the foundation  1050 . The concrete beneath the foundation frame  450  from the sides will eventual meet to form a single uninterrupted piece of concrete in the foundation  1050 . During this pour per the process  150 , the concrete will also rise to fill in the areas between the sidewall frames  455  and the pit walls  510  to form the sidewalls  1040  and between the headwall frames  475  and the pit walls  510  to form headwalls  1030  as shown in  FIGS. 5   a - e . The concrete will also flow between the baffle frames  460  forming the baffle  520 . This process is shown in  FIGS. 5   a - 5   e  with an illustration of the concrete level  580  rising. 
         [0040]    During the pouring process, the floating form  530  may be removed. In the exemplary embodiment, this may be accomplished by securing the sidewall frames  455 , headwall frames  475 , and baffle frames  460  in a manner that removes the need for them to be connected to the foundation frame  450 . In an exemplary embodiment, a series of braces may be deployed that exerts a force on the sidewall frames  455  A, B, C, D that are across from each other, and the headwall frames  475  A, B across from the corresponding baffle frames  460  A, B as applicable per the process  155 . The force these braces exert should be sufficient that they balance the force of the concrete pushing back on the braces. With the sidewall frames  455 , headwall frames  475 , and the baffle frames  460  now braced independent of the foundation frame  450 , the foundation frame  450  may now be removed per the process  160 . The sidewall frames  455 , headwall frames  475 , and the baffle frames  460  will be held in place until such time as the concrete forming the sides of the septic tank  1000  have hardened. 
         [0041]    The removal of the foundation frame  450  now exposes the floating form  530 . The floating forms  530  may now be removed from the base on the septic tank  1000 . The concrete forming the base of the septic tank  1000  should not be set, but should have sufficient plasticity to substantially keep its shape once the floating forms  530  are removed. The openings in the base of the septic tank  1000  resulting from the removal of the floating forms  530  may now be filled with additional concrete that will fuse with the concrete in the base to form a single unit per the process  165 . 
         [0042]    Once the concrete hardens per the process  170 , the braces holding the baffle frames  460 , headwall frames  475 , and sidewall frames  455  are removed per the process  175 . The baffle frames  460 , headwall frames  475 , and sidewall frames  455  are then removed along with the blocking mold  465  per the process  180  shown in  FIG. 6 . The removal of the blocking mold  465  creates the baffle aperture  525 . If a secondary frame  910  is used, it is removed as well. This process will make the foundation  1050 , sidewalls  1040 , headwalls  1030 , and baffle  520  of the septic tank  1000  from a single piece of concrete. 
         [0043]    When the septic tank  1000  is in operation, waste water will come in through the inlet opening  710  where it will flow into the first chamber  590 . The solid components will rest in the first chamber  590  while water flows  720  into the second chamber  595  as shown in  FIG. 7 . From the second chamber  595  the waste water will flow  740  to the outlet opening  750 . 
         [0044]    Mold Guided Method For Creation of Septic Tank 
         [0045]    In an alternate embodiment show in  FIG. 2 , a mold frame  540  may be used to form a septic tank  1000 . The mold frame  540  would appear to be two chamber molds  545  that are coupled together by a baffle connection  550  that is substantially similar to that of the blocking mold  465  from the previously disclosed embodiment. The mold frame  540  would appear to be a structure that has equivalent dimensions and displacement as the previously described system of foundation frame  450 , baffle frame  460 , sidewall frames  455 , headwall frames  475 , and blocking molds  465  as previously described. The width of the blocking mold  465  would be the same as the desired baffle  520  thickness. The two chamber molds  545  would accomplish substantially the same purpose as the foundation frames  450 , sidewall frames  455 , headwall frames  475 , and baffle frames  460 . The chamber molds  545  and baffle connection  550  also act substantially as the foundation frame  450  in the previously discussed embodiments. Further, while this embodiment may use a floating form  530  to keep the mold frame  540  above the pit bottom  515  as previously discussed, it may also be suspended above the pit bottom  515 . 
         [0046]    In an exemplary embodiment using a mold pour method  200 , the pit may be excavated per the process  205  as in the previous embodiment. As in the previously disclosed embodiment, there is a choice to use a secondary frame  910  per the process  210 . 
         [0047]    Mold Guided Method-Mold Only 
         [0048]    If the secondary frame  910  is not used, the mold frame  540  is suspended above the pit bottom  515  per the process  230 . The mold frame  540  will be suspended in such a manner that there is sufficient space between the pit walls  510  and mold frame  540  to allow concrete be poured between the mold frame  540  and the pit walls  510  while at the same time allowing the concrete to flow between the pit bottom  515  and the bottom of the mold frame  540 . As the concrete level rises, it will also fill in the space between the chamber molds  545 , creating the baffle  520 . 
         [0049]    Mold Guided Method-Secondary Frame 
         [0050]    If a secondary frame  910  is used, then it is to be installed in the pit per the process  215 . To use the secondary frame method, the mold frame  540  is used as previously disclosed in the mold only method. A secondary frame  910  is then erected per the process  215  between the mold frame  540  and the pit walls  510 . This allows the concrete to be poured as previously disclosed in the mold only method, but not to interact with the pit walls  510  directly. The secondary frame  910  runs parallel to the sides of the mold frame  540 . The concrete is poured in the space between the mold frame  540  and the secondary frame  910 . The formation of the sides of the septic tank  1000  as an integrated unit is achieved as in the mold only method, but the concrete flow is more carefully controlled. This also allows for builders to interface with the septic tank  1000  before it is covered without excavating more soil. If an above ground septic tank  1000  is built using a mold frame  540 , this method maybe used. 
         [0051]    Mold Guided Method-Openings 
         [0052]    Septic tanks  1000  typically have at least one inlet opening  710  and one outlet opening  750 . If the inlet openings  710  and outlet openings  750  are to be on the sides of the septic tank  1000  per the process  220 , then the mold frame  540  (and secondary frame  910  as applicable) may further comprise projections  480  for the concrete to flow around so that the inlet openings  710  and outlet openings  750  may be maintained for connections. In an exemplary embodiment utilizing the mold only method, a removable projection  480  will be installed per the process  225  out of the mold frame  540  where the inlet openings  710  and outlet openings  750  are required. This projection  480  would extend far enough to make sure no concrete blocks the inlet opening  710  or outlet opening  750  when the concrete cures. If the secondary frame method is used per the process  210 , then the projection  480  would connect the mold frame  540  and the secondary frame  910  at the desired inlet opening  710  and outlet opening  750  locations per the process  235 . Once the concrete has been poured per the process  240  and sufficiently hardened, the projections  480  are to be removed to show the openings. 
         [0053]    In an alternative embodiment, the actual inlet pipes and outlet pipes to be used by the septic tank  1000  may be used to form the inlet openings  710  and outlet openings  750  in the place of projections  480 . The pipes may be installed, and the mold frame may be suspended adjacent to them. When the concrete is poured, the concrete will flow around the pipes, creating the openings necessary in the septic tank  1000  for access. 
         [0054]    If the inlet openings  710  and outlet openings  750  will be on the top surface of the septic tank  1000 , then none of these inlet openings  710  and outlet openings  750  will be needed in the sidewalls  1040  or headwalls  1030 . The inlet openings  710  and outlet openings  750  may be part of the lid  1010 , which will be discussed below. 
         [0055]    The pipes used to transport the waste water are four inches pipes in an exemplary embodiment. However, pipes of different sizes may be used without departing from the spirit of this invention. 
         [0056]    Mold Guided Method-Pour 
         [0057]    Once the mold frame  540  has been suspended over the pit bottom  515  and the projections  480  have been made (if applicable), then the concrete is poured per the process  240 . 
         [0058]    In the exemplary embodiments, the concrete will flow until it completely fills the space between the mold frame  540  and the pit walls  510  (or secondary frame  910  if applicable). The concede flow will also fill the space between the pit bottom  515  and the mold frame  540 . The space between the two chamber molds  545  would also be filled in to create the baffle  520 . The mold frame  540  acts in substantially the same manner as the foundation frame  450 , sidewall frames  455 , and headwall frames  475  did in the single frame method described above. Once the concrete reaches sufficient hardness per the process  245 , the mold frame  540  may be removed by decoupling the chamber molds  545  from the blocking mold  465  per the process  250 . With both chamber molds  545  removed, the blocking mold  550  and the projections  480  would also be removed as well to allow access between the two chambers per the process  250 . If a secondary frame  910  was used, then it is removed as well. 
         [0059]    If this method is followed, the inlet pipes and outlet pipes may be connected for operations if the openings are in the sidewalls. The methods for allowing connections by removable projection  480  that are coupled to the frames are used as described in the frame guided pour method. 
         [0060]    Lid Formation 
         [0061]    Once the foundation  1050 , sidewalls  1040 , headwalls  1030 , and baffle  520  are set, the lid  1010  may be added. The lid  1010  may be a separate component that can be constructed on site and then placed on top of the open septic tank  1000  as shown in  FIG. 3   300 . The lid  1010  may be created by use of a lid mold, which is formed per a lid mold per the process  305 . 
         [0062]    The lid  1010  is not part of the septic tank  1000  as the lid itself is not necessary for operations therefore it can me formed from a different pour than the septic tank  1000  without departing from the scope and spirt of this invention. 
         [0063]    Lid Formation-Openings 
         [0064]    If the septic tank  1000  was designed to have the inlet openings  710  and outlet openings  750  in the lid  1010  per the process  310 , then there may be projections  480  installed per the process  315  in the lid mold that allow inlet opening  710  and outlet opening  750  to be created in the lid  1010 . Further, the lid frame may also allow for a utility opening per the process  320  (or clean out plug) in the lid  1010 , per the process  325  so that the interior of the septic tank  1000  may be accessed for maintenance if needed. Once the concrete is poured per the process  330  and the lid  1010  has hardened per the process  335 , the projections  480  may be removed per the process  340 , opening up the applicable inlet openings  710 , outlet openings  750 , and maintenance openings  1020 . 
         [0065]    If this method is followed, the utility connection for the input pipes and outlet pipes may be connected for operations if the openings  1020  are in the lid  1010  once the lid  1010  is installed. 
         [0066]    The lid  1010  may now be installed on top of the septic tank  1000  per the process  345 . 
         [0067]    Sealing Pour 
         [0068]    In a further exemplary embodiment, once the septic tank  1000  is finished, an optional final pour may be used to fuse the septic tank  1000  and lid  1010  as single unit. In an exemplary embodiment, projections  480  are placed in the inlet opening  710 , output opening  750 , and utility opening  1020  (if applicable) to protect them during a final pour. The entire septic tank  1000  is then covered in a final pour, fusing the lid  1010  to the septic tank  1000 . Any projections  480  are then removed to allow future access to the septic tank  1000 . Alternatively, the actual connection pipes may be used in place of the projections  480  to make sure concrete does not block any openings. 
         [0069]    Portable Frames 
         [0070]    Some concrete septic tanks  1000  created by these exemplary methods will require frames to control the shape of the concrete before it becomes solid. While each septic tank  1000  may have frames constructed on site out of available materials, this may require frames to be built for each septic tank. 
         [0071]    One option is to have a set of prefabricated frames available for use at each installation. However, there will need to be multiple frames for different sized projects. There may be standard sizes constructed, but the frames may not address the different sizes and numbers of connections needed for each septic tank  1000 . 
         [0072]    An alternate embodiment would be to have an adjustable frame that can extend or contract to different dimensions. The frame may have multiple removable projections  480  that can be used to create inlet openings  710  and outlet openings  750  as needed for the septic tank  1000 . These frames may extend in the way of accordion like walls, may telescope laterally, or have multiple segments coupled together to become the desired length. Such a versatile frame would allow a single frame set to accommodate various project sizes. 
         [0073]    In an exemplary embodiment, the frame would be an erectable structure capable of providing shape to a product made of a pourable castable material, comprising: a foundation element to define the base of said product, and a sidewall element to define the sidewalls of said product. In an additional exemplary embodiment, the erectable structure further comprises at least one projection to define an opening in said product. In an additional exemplary embodiment, the erectable structure further comprises a projection to define a baffle aperture in said product. 
         [0074]    Additional Elements 
         [0075]    While the disclosed embodiments have involved construction at the site of installation, it will be understood that these same procedures may be used to create a concrete septic tank  1000  at another location and transported to the final location. It is also understood that the resulting septic tank  1000  may be installed above ground. Additionally, all the disclosed methods will allow for the construction of a septic tank  1000  of sufficient strength to handle the stresses typically associated with septic tank  1000  operations. Further, this method may be modified to handle septic systems on a larger scale, including sewers. 
         [0076]    Therefore, the foregoing is considered illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the method to the exact steps and operations shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the method.