Abstract:
A system and method for removing contaminated pilings is provided, the system including a casing to enclose the piling and a pressurized air system for excavating soil and contaminated materials from around the piling and material from the piling itself, capturing the excavated soil and contaminated material as it rises within the piling by action of the pressurized air, and a closure mechanism at the bottom of the casing for enclosing and removing the piling without spreading contamination to the surrounding environment. Clean fill material, such as sand, can be injected through the air nozzles or optional sand ports on the casing to fill the void left from the removed piling.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The disclosed embodiments of the invention pertain to the removal of contaminated objects from soil, and, more particularly, to a system and method for excavating contaminated soil surrounding a piling, removing the piling and the contaminated soil, and filling the resulting hole with uncontaminated material. 
     2. Description of the Related Art 
     Pilings and similar support structures, such as fence posts, telephone poles, and light poles, are frequently treated with a preservative to resist corrosion and decay when mounted in the soil. In the past, creosote has been one preservative used to protect the wood. It has been discovered that creosote and other preservatives can be damaging to the environment and harmful to nearby life. 
     More particularly, creosote can seep into the soil surrounding the posts and pilings and pollute the soil, causing damage to plants growing nearby and endangering animal and human life as well as aquatic life. For example, barnacles, muscles, and similar aquatic life can attach themselves to creosote-treated pilings, becoming themselves contaminated. Marine life feeding on this contaminated material become contaminated and will in turn spread the contamination. Hence, there is a need to replace aging posts and pilings with environmentally safe substitutes. 
     Removing old posts and pilings, however, presents a number of challenges, not the least of which is causing further environmental damage in the removal process, and increased danger to nearby aquatic and animal life. For example, disturbing the contaminated soil and material attached to a piling while attempting to remove the piling will spread the contamination beyond the immediate area. Moreover, older pilings that have rotted tend to break apart when pulled upward, further spreading the contamination and making it more difficult to remove the remaining stub. 
     A number of devices have been proposed for removing pilings and the like. However, none of these address or solve the problem of containing and removing contaminants along with the piling. For example, U.S. Pat. No. 3,379,265 directed to a pile extractor and setter discloses lowering a casing over a piling and injecting liquid, such as water, or a gas, such as air, through nozzles on the casing to assist in driving the casing into the soil so that teeth on the casing will dig into the earth or sea bottom. In this device, excavated mud is expelled through mud slots in the casing into the surrounding water, which would further spread contaminants associated with the piling and the surrounding soil. 
     As another example, U.S. Pat. No. Re. 28,945 discloses an apparatus for excavating a tailing pond where high pressure liquid is jetted from inside a caisson to the soil on the outside of the caisson to create a pulping zone surrounding the caisson. The slurry formed in the pulping zone flows through portals in the bottom of the caisson into a slurry sump where it is pumped out to excavate the soil. Here, the outwardly-oriented water jets create a cloud of slurry outside the caisson that spreads throughout the water, extending the zone of contamination far beyond the immediate area. 
     Yet another example is an apparatus for removing piles disclosed in U.S. Pat. No. 1,644,560, wherein a plurality of pipes are lowered around the outside of a piling and high pressure water is forced out the bottom of the pipes to excavate the soil around the piling. In this device, the jetted water and loosened soil are not contained, resulting in a spreading of any contamination in the soil. 
     In a related device disclosed in U.S. Pat. No. 4,644,715, a soil-excavating sleeve having teeth on the bottom, interior doors, and flaps on the sides of the sleep, is rotated into the ground around a utility pole for half its length and left in place. The soil is excavated by the action of the doors or flaps forcing the soil out of the cylinder. The excavated annulus of soil is then filled with hardenable material and the sleeve is left in place as a re-enforcement to the utility pole. Here, the pole and the sleeve are left in the ground where the contamination can continue to spread, and not all of the contaminated soil is removed. 
     Hence, there is a need for a device that can excavate the soil surrounding a contaminated post or piling and remove the soil and the post or piling without endangering the environment and nearby life. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is directed to a system and apparatus for excavating a contaminated object, such as a post or piling. In accordance with one embodiment of the invention, an excavation device is provided for removing an object from the soil, the device having a casing sized to be slidably received over the object and an excavation system associated with the casing for removing soil from around the object, the system using pressurized air to force soil to rise inside the casing and to remove the rising soil from the inside of the casing. Ideally, a mixture of pressurized air and liquid is used in environments where the soil is not under water. 
     In accordance with another aspect of the foregoing embodiment, the excavation system includes a plurality of nozzles associated with the casing and is configured to direct a stream of pressurized fluid, ideally comprising high-pressure air, towards the object and the soil to remove material from the object and excavate the soil; and a device for removing the excavated soil from within the casing. The removing device can comprise a suction hose or a filter for capturing the removed material and excavated soil. 
     In accordance with a further aspect of the foregoing embodiment, a closure mechanism is provided at one end of the casing used under water to enclose the object within the casing as the object is removed. 
     In accordance with still yet another aspect of the foregoing embodiment, ballast is provided to be attached to the casing for giving additional weight to the casing and to be used in replacing the removed soil and the void left by the removed object. 
     In accordance with another embodiment of the invention, a system is provided for removing a post from soil that includes a casing sized to be slidably received over the piling; and an excavating system for excavating soil from around the piling using pressurized air to force soil to rise inside the casing and to remove the soil from inside the casing; a device for forcing the casing into the soil; and a device for pulling the post from the soil. 
     In accordance with another embodiment of the invention, a system is provided for removing a piling from soil under water, the system including a casing having an interior sized to be slidably received over the piling; a plurality of air nozzles mounted near a first end of the casing and oriented to direct pressurized air at least towards the soil and also towards the piling to loosen soil from around the piling and to remove material from the piling, and to force the soil and removed material to rise to the surface of the water; and a device for capturing and removing the soil and material from the water in the interior of the casing. 
     In accordance with another embodiment of the invention, a method is provided for removing a post from soil, the method including placing a casing around the post; driving a casing into the soil; excavating soil from around the post using pressurized air to force the soil to rise inside the casing and removing the soil from inside the casing; and removing the post. 
     In accordance with still yet another embodiment of the invention, a method is provided for removing a piling from soil under water, the method including placing a casing around the piling; driving the casing into the soil; directing at least pressurized air through nozzles on the casing to the soil around the piling to loosen the soil and force the soil to rise upward inside the interior of the casing; removing the rising soil from the interior of the casing; and removing the post. Ideally, the air nozzles are also directed to the piling to remove contaminated debris from the piling, and the debris is forced to rise upward inside the casing. 
     In accordance with another aspect of the foregoing embodiment, the method further includes enclosing the bottom of the casing when the piling is removed to ensure all of the piling materials are removed from the water. Ideally, a fill material is injected in the remaining void to replace the removed soil and the piling. 
     As will be readily appreciated from the foregoing, the advantages of the present invention are that it completely contains the contaminated material as it is being excavated from around the piling and from off of the piling, including the soil, barnacles, and the like. This material is then forced to rise upward within the casing by the rising air from the pressurized nozzles. Because the casing completely surrounds the piling, and the pressurized air is injected within the casing and directed at the soil and the piling, the removed material and the excavated soil remain within the casing instead of spreading the contamination outside the immediate area. The optional doors on the bottom of the casing enclose the pole or piling as it is being lifted to ensure that all of the debris and other material associated with the contaminated object are removed from the water without spreading the contamination. The air nozzles can also be used to inject a fill material into the area where the object was removed to replace the excavated soil. Optional ballast to give the casing weight can sand that is later used to replace the soil and fill the void left by the removed object. It can be appreciated that the present invention can be modified for use in land operations where a mixture of air and water are injected inside the casing to excavate the soil surrounding the object. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
     The foregoing and other features and advantages of the present invention will be more readily appreciated as the same become better understood from the following detailed description when taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a side view of a contaminated piling in the water; 
     FIG. 2 is a cross-sectional side view of an excavation device formed in accordance with the present invention; 
     FIG. 3 is a side view of one embodiment of the excavation device formed in accordance with the present invention installed over an existing piling; 
     FIG. 4 is a side view of an extractor casing being driven into the soil and the excavation thereof from around the bottom of the piling; 
     FIG. 5 is a side view of another embodiment of the invention having a telescoping casing for filing holes with uncontaminated material; 
     FIGS. 6A-6D are side views of a system and method of using of the embodiment of FIG. 2 for removing a piling and filling the resultant void; 
     FIGS. 7A-7C are sides views of an alternative method using the embodiment of FIG. 4; and 
     FIGS. 8A-8B are isometric views of yet another embodiment of a device for removing pilings formed in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring initially to FIG. 1, shown therein is a piling  10  having a bottom end  12  anchored in the soil  14  beneath a body of water  16 , above which the top end  18  of the piling  10  projects. As can be seen therein, the bottom  12  of the piling has deteriorated and released contaminants (shown as stippling  22 ) into the soil. Material  24  attached to the piling below the water level, representing barnacles, muscles, and the like, have attached themselves to the piling surface  20  above the level of the soil  14 . Although the embodiments described herein are used to extract a piling, it is to be understood that the invention may be used in the excavation of other objects, such as posts, poles, and the like. 
     Turning next to FIG. 2, shown therein is an extraction device  28  formed of an extractor casing  30  having sidewalls  32  sized to define an internal diameter d 1 , which ideally is sized to be 8 to 16 inches larger than the diameter of a piling to be removed (not shown in FIG.  2 ). In a preferred embodiment, the diameter d 1  is 12 inches larger than the piling, thus providing a 6-inch clearance on all sides of the piling. The cross-sectional configuration of the casing  30  can be shaped to accommodate the cross-sectional configuration of the piling, i.e., square, round, or other shape. At the top  34  of the casing  30  is a truncated cone-shaped funnel  36  having an open top  38  that defines a smaller diameter d 2,  which is smaller than the internal d 1  of the main body of the casing  30 . The casing  30  thus has a longitudinal internal bore defining an interior  40  that opens at one end through the opening  38  and that opens at the other end  42  through a second opening  44 . The funnel  36  is attached at the top of the casing  30  over the second opening  44 . 
     A supply line  46  is shown associated with the exterior of the casing  30  and having at a terminal end a plurality of nozzles  48  mounted at the lower end  42  of the casing  30 . The nozzles  48  are oriented to point towards the interior  40  of the casing  30 . Ideally, at least a portion of the nozzles  48  will point downward towards the soil (not shown in FIG. 2) encompassed by the lower end  42  of the casing  30 . The supply line  46  is configured for attachment to a source of pressurized fluid, such as pressurized air, or pressurized water, or a mixture of pressurized air and water. A second set of nozzles  50  are positioned above the first set of nozzles  48  and are angled to point downward towards the second opening  44 . Additional sets of nozzles may be positioned around the interior  40  of the casing  30  as desired. The orientation of the nozzles  48 ,  50  is selected to direct the pressurized fluid to either the soil surrounding the piling, to the piling itself, or to both the piling and the soil. When directed to the soil, the nozzles direct the pressurized fluid, preferably pressurized air, to loosen the soil, forcing the soil to rise upward within the interior  40  of the casing  30  by action of the rising air bubbles from the pressurized air. The nozzles  48 ,  50  can also be oriented to direct the pressurized air to the piling itself to remove the material clinging thereto, which is also forced to rise with the rising air bubbles from the pressurized air to the surface of the water. 
     In another embodiment, a third set of nozzles  76  are provided midway up the interior sides  32  of the casing  30  and are pointed upward to assist in urging the removed material and excavated soil upward to the top of the casing  30 . It is to be understood that at least one of these nozzles  76  may be used as desired and positioned throughout the interior  40  of the casing  30  as desired. 
     The funnel-shaped top  36  may be integrally formed with the casing  30  or attached to the top of the casing  30  with suitable fasteners or latches as are conventionally known and commercially available. The funnel-shaped top  36  is designed to force the rising air bubbles and entrained soil and material through the opening  38  at the top thereof and out of the casing  30 . The emerging air bubbles and soil and material exit the funnel-shaped top  36  and spill down the sides  52  thereof. In one embodiment, a trap  54  is provided at the top of the casing  30  to surround the funnel-shaped top  36  as shown in FIG.  2 . The trap  54  has an outer wall  56  defining an opening  58  at the top thereof. The outer wall terminates at a bottom wall  60  that circumscribes the top of the casing  30 . An angled interior wall  62  joins the bottom wall  60  and is formed at an angle that matches the angle of the funnel-shaped top  36 . The angled interior wall  62  circumscribes an opening  64  that matches in size and shape the opening  38  defined by the funnel-shaped top  36 . 
     The trap  54  is designed to capture the material and soil that rises through the opening  38  in the casing top  30  and spills over the angled interior walls  62  positioned on top of the sides  52  of the funnel-shaped top  36 . In one embodiment, a suction hose  66  is attached to the trap  54  to suction out the contaminated material and debris. In another embodiment, the trap  54  can be detached and lifted from the top of the casing  30  and turned over to empty the contaminated material and soil therefrom. 
     Also shown in FIG. 2 is an optional ballast container  70  attached to the exterior  72  of the casing  30  to provide extra weight for the casing as it is being urged down into the soil. The ballast container  70  ideally is filled with sand  71  or other uncontaminated material  74  that can later be used to fill in the void created by the removed piling and to replace the excavated contaminated soil, as described more fully herein below. 
     In a further embodiment, a closure mechanism  78  is provided at the bottom  42  of the casing  30  to enclose the casing  30  and the piling during removal of the piling. Ideally, the closure mechanism  78  consists of one or more doors  80  that are hydraulically or electrically actuated when the bottom of the piling is pulled into the interior  40  of the casing  30  or when the casing  30  has its bottom  42  driven below the bottom of the piling. In another configuration, the doors  80  may be spring loaded to automatically close as it passes by the bottom of the piling. Alternatively, the doors  80  may be actuated when a sensor detects the passage of the bottom of the piling. Preferably the doors  80  seal the bottom  42  of the casing  30  to prevent the escape of any contaminated soil or removed material or piling debris. However, the doors  80  may be provided with drain holes to allow the drainage of water as the casing  30  and piling are lifted out of the water to reduce the amount of weight that must be lifted. 
     Ideally the casing  30  is constructed of strong material, such as ¾ inch to 1 inch thick heavy-duty steel, preferably sharpened at the bottom adjacent the lower end  42 . To facilitate installation and removal as well as storage and transportation of the casing  30 , the casing  30  may be constructed in two or more sections that are bolted together. The sections may be vertically attached together to accommodate the length of the piling, or they may be longitudinal sections that are attached together at their sides in a conventional manner. 
     Turning next to FIG. 3, shown therein is a device  82  for removing a piling  84  from the soil  86  below a body of water  88 . The device  82  includes a casing  90  that has been forced down below the bottom  92  of the piling  84  such that the doors  94  have closed therebelow. The dead marine life  96  and excavated soil  86  have been removed from the casing  90  through the trap  100  at the top thereof. The trap  100  includes pickup rings  102  for attachment to a crane or other lifting device  104  (shown in FIG. 4) by chains  106  or cables. Although not shown herein, the trap  100  can contain a walkway on the interior for workmen to stand on while fastening the trap  100  to the casing  90  and the chains  106  to the pickup rings  102 , and while attaching a choker cable to the piling  84 . The trap  100  is constructed of reinforced steel to enable the use of a vibratory hammer  142  (shown in FIG. 4) to drive the casing  90  into the soil  86 . 
     In this embodiment, the piling  84  has been cut so that it projects above the surface  108  of the water  88  to enable attachment of a choker cable (shown as  202  in FIG. 6D) that extends up through the opening  110  in the funnel-shaped top  112  on the casing  90 . 
     FIG. 4 shows another embodiment of the invention wherein a casing  114  is received over a piling  116  that is below the surface  108  of the water  88 . A sediment trap  118  is formed at the top  120  of the casing  114  to capture sediment exiting from the funnel-shaped top  122  on the casing  114 . Because the piling  116  has its top  124  below the water surface  108 , it is not feasible to attach a choker chain to the piling to remove it from the soil  86 . Hence, the trapdoors  126  at the bottom of the casing  128  are used to lift the piling  116  out of the water  88 . The plurality of nozzles  130  mounted on the casing  114  are supplied by an air line  132 , as previously described, that is connected to a source of pressurized air  134  that in this embodiment is attached to a floating support, such as a barge  136  or other vessel. 
     Because this embodiment does not have a removable trap, the sediment trap  118  is emptied by a surface suction unit  138  via a hose  140  attached to the sediment trap  118  below the surface  108  of the water  88 . 
     As shown in FIG. 4, a vibratory hammer  142  is used to drive the casing  114  into the soil  86 . The hammer  142  is suspended from the crane  104  that in turn is supported by the barge  136  or vessel. Vegetable oil or other environmentally safe non-compressible fluid should be used for the hydraulic equipment associated with the hammer  142 . 
     Turning to FIG. 5, shown therein is yet another embodiment of the invention wherein a telescopic casing  144  is used to decontaminate a hole  146  left by a previously-removed piling. Here, the telescopic casing  144  projects down into the hole  146  and the nozzles  148  are used to inject sand  150  supported on a barge  152  into the hole  146 . Flexible hoses are used on the telescopic casing  144  to accommodate the extension and retraction of the casing  144 . 
     It is to be understood that the disclosed embodiments of the invention can be adapted for land use to remove contaminates around the base of power poles, telephone poles, and the like, or from pilings projecting from wetland, marshes, and generally in sensitive areas where water is not a factor. In this case, high pressure air with water added as needed is provided to the nozzles, which causes the water to rise within the casing along with the entrained soil and debris, which is then suctioned off from the top. 
     FIGS. 6A-6D illustrate one method of extracting a contaminated piling  154  from soil  156  under water  158  using the device  160  substantially as shown and described above with respect to FIG.  2 . Initially, the diameter and height of the exposed portion  162  of the piling  154  above the surface  164  of the water  158  is measured. The remaining length of the piling  154  above and below the surface of the water can either be estimated or it can be measured by equipment that is readily commercially available, which will not be described herein. 
     Once the estimated or actual length of the piling  154  is determined, the piling top  166  is cut to project a few feet above the water surface  164 , as shown in FIG.  6 B. This is to enable attachment of a choker chain or similar device to the piling  154 , as described in more detail hereinbelow. Allowance is also made for fluctuations in the water surface  164  due to wind, wave action, and tides. However, the piling top  166  should not extend much higher than a few feet above the water surface  154  to avoid having to construct the casing longer than necessary and to avoid having to raise the water level inside the casing any higher than necessary. As described more fully below, the water level in the casing needs to be higher than the piling top  166  in order to force the air bubbles and entrained soil and debris to enter the trap. Of course, in embodiments where the rising soil and removed material are suctioned off, the height of the piling may vary from that described above. 
     As shown in FIG. 6C, the casing  168  is then assembled, preferably in the field, to the diameter and estimated length of the piling  154 . As previously described, the inside diameter d 1 , as shown in FIG. 2, is 8 to 16 inches larger than the diameter of the piling to leave a circumscribing space of 4 to 8 inches, and ideally a space of 6 inches, between the piling  154  and the inside surface  170  of the casing wall  172 . This forms a chamber  174  that directs the excavated soil and removed debris rising upward with the air bubbles from the pressurized air. (The fluid nozzles and closure doors are not shown in this view of the casing.) It is noted that the deeper the water, the greater will be the pressure to force the air bubbles to rise upward within the chamber  174 . 
     The assembled casing  168  is then attached to a lifting device, such as the crane  104 , which may be land based or supported by a vessel  176  on the water  158 . Weight and lifting capacity permitting, the casing  168  can be assembled to include the funnel-shaped top  178  and the trap  180 , which are lowered as a unit. In this mode, the choker chain may be first attached to the piling  154  and left on the exposed top to facilitate its retrieval and use after the assembled device  160  is lowered over the piling  154 . 
     As the casing bottom  182  is slidably received over the piling  154 , it will contact the soil  156  or the layer of debris  184  thereon. With the casing  168  at rest, the air hoses  186  are connected to a source of pressurized air  188 . If used, the suction hoses (not shown) are also connected to a vacuum source. The vibratory hammer  190  is then used in conjunction with the crane  104  to drive the casing  168  into the soil  156 . Pressurized air  192  is directed to the soil  156  at this time to loosen and excavate the soil  156  surrounding the piling  154 . In addition, pressurized air  192  can be directed onto the piling  154  in order to clear material  194  thereon. However, caution should be used because decayed pilings can be blown apart by high-pressure air. Movable nozzles can be used in conjunction with the casing  168  to enable dynamic orientation of the nozzles from a remote location as the casing  168  is driven into the soil  156 . 
     As the casing bottom  182  passes the bottom extremity  196  of the piling  154 , which can be detected by a remote sensor (not shown) on the casing  168 , which was described above, driving of the casing  168  into the soil  156  is stopped. Optional water jets  198  mounted on doors  200  at the casing bottom  182  can be used to completely remove the soil  156  underlying the piling  154 . To prevent the piling  154  from settling further into the soil  156 , the choker chain  202  previously attached to the piling top  166  is connected to the crane  104  and an upward force is exerted on the piling  154 . 
     The high-pressure air  192 , and water if used, will remove the sludge, debris, and contaminated material, forcing it to rise up the chamber  174 , which is formed between the casing  168  and the piling  154 , and it is removed at the piling top  166 . Because certain contaminants, such as creosote, have a tendency to rise with the silt and excavated soil  156 , the contamination will remain contained within the casing  168  until it is removed through the trap  180  or is suctioned off. 
     After the bottom extremity  196  of the piling is cleaned and the underlying soil  156  excavated, the doors  200  are shut to enclose the piling  154  in the casing  168 . The piling  154  and the device  160  are then lifted out of the water. To prevent unnecessary lifting of the water and to reduce the weight to be lifted by the crane  104 , drains may be provided in the casing  168  or in the doors  200  to let some or all of the water out. 
     Prior to removing the device  160 , uncontaminated sand or other fill material may be injected into the void  204  that remains in the soil  156  after removal of the piling  154 . The void  204  can be filled with sand that is pumped through the air hoses  186  and the nozzles  206  located at the casing bottom  182 . 
     FIGS. 7A-7C show an alternative method wherein the piling  154  is cut below the water surface  164  as shown in FIG.  7 A. In this event, the assembled device  208  is constructed so that the top of the trap  180  is above the water surface  164 . Instead of attaching a choker cable to the piling, the casing  168  is driven below the bottom extremity  196  of the piling  154 , and the doors  200  close off the casing bottom  182  to encase the piling  154  therein as shown in FIG.  7 C. 
     Another embodiment of the invention is shown in FIG. 8A, wherein a device  210  is shown having a casing  212  with external combination air and sand lines  214  formed on an exterior surface  216  at the top half  218  of the casing  12  and then passing through the casing wall  220  to be mounted on the interior  222  of the casing  212  on the bottom half  224  of the casing  212 . This accommodates the piling taper, i.e., the reducing diameter of the piling from the top to the bottom of the piling  226 . 
     Also shown in FIG. 8A is a modified trap  228  having a filter basket  230  with at least one door  232 , and at least three doors formed thereon in a preferred embodiment, that can be opened for cleaning the filter basket  230 . More particularly, as shown in FIG. 8B, the filter basket  230  can be removed and placed inside a housing  234  that is received within a shipping container  236 . The doors  232  can be opened to enable cleaning of the filter basket  230  and washing of debris therein into the container  236 , where it can either be treated at that time or shipped to an outside treatment facility to decontaminate the material. In one embodiment, the doors  232  are hingedly attached to the filter basket  230  by hinges  238  at the top of each door  240 . The doors  232  swing outward away from the exterior of the filter basket  230 . 
     Referring back to FIG. 8, a locking cap  242  having a rubber gasket is attached to the top  244  of the funnel-shaped top  245 , thus sealing the inside of the casing  212 . This will help in a difficult extraction by enabling use of air pressure for extra lift as pressurized air evacuates the water from inside the casing  212 . This can also aid in decontamination by sealing the casing  212  so that the churning action of the pressurized air is given extra power. 
     As shown at the bottom  246  of the casing  212 , optional sand portals  248  are provided that direct decontaminated sand into the void  254  created by the removed piling  226 . As shown in this embodiment, the sand  250  is directed below the doors  252  at the casing bottom  246 . This permits the sand  250  to be injected into the void  254  after the piling  226  is sealed inside the casing  212  by the doors  252 . 
     Although representative embodiments of the invention have been illustrated and described herein, it is to be understood that various changes may be made therein as will be obvious to those of ordinary skill in the art without departing from the scope of the invention. Hence, the invention is to be limited only by the scope of the appended claims and the equivalents thereof.