Abstract:
A self contained fire extinguisher system that does not need external power in order to sense or initiate a release of a fire suppression medium, includes components configured to utilize a linear sensor network that can be connected to at least one and/or different sources of fire suppression mediums. A linear temperature sensing cord can be routed over a large area not practical with individual sensors. The cord can also actuate several and different sources of fire suppression mediums to maximize the suppression of a fire.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application is a continuation of U.S. patent application Ser. No. 14/507,635 titled “Self Contained Fire Extinguisher System Including A Linear Temperature Sensor” filed on Oct. 6, 2014, now allowed; which is a continuation of U.S. patent application Ser. No. 13/096,901 titled “Self Contained Fire Extinguisher System Including A Linear Temperature Sensor” filed on Apr. 28, 2011, issued as U.S. Pat. No. 8,851,197 on Oct. 7, 2014, the entire content of each of which is herein expressly incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present disclosure generally relates to self contained fire extinguisher systems. More particularly, the present disclosure relates to self contained fire extinguisher systems that do not need external power in order to sense or initiate a release of a fire suppression medium. 
         [0003]    Examples of applications for embodiments according to the present disclosure include kitchens, terrestrial vehicles, marine vessels and aircraft. These applications may be civilian, commercial or military. 
       DESCRIPTION OF CONVENTIONAL TECHNOLOGY 
       [0004]    Certain conventional fire extinguishing systems typically include a manually operated, pressurized source of a fire suppression medium. Other conventional fire extinguishing systems may include a sensor that requires external power to send an initiation signal to a source of a fire suppression medium, e.g., a pressurized cylinder, which is remotely located from the sensor. These sensors may detect heat and/or smoke by electrical means. If the electrical power is interrupted or disengaged by collateral damage or due to the fire, these conventional fire extinguishing systems may be rendered inoperative. 
         [0005]    Military vehicles are examples of applications that are sensitive to loss-of-power to an onboard fire extinguishing system because the crew is frequently in close confinement with limited egress opportunity and no access to back-up fire suppression mediums. Moreover, a fire aboard a military vehicle may be caused by a landmine, projectile or other violent event that may result in immediate, collateral damage to the power network for the vehicle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1A  is a cross-section view of an embodiment of a linear temperature sensor cord according to the present invention. 
           [0007]      FIG. 1B  illustrates a method for manufacturing the linear temperature sensor cord shown in  FIG. 1A . 
           [0008]      FIGS. 1C-1E  are perspective and cross-section views of variations of the linear temperature sensor cord shown in  FIG. 1A . 
           [0009]      FIGS. 2A and 2B  are perspective views of embodiments of protection for the linear temperature sensor cord shown in  FIG. 1A . 
           [0010]      FIGS. 3A-3C  are perspective views of attaching devices for the linear temperature sensor cord shown in  FIG. 1A . 
           [0011]      FIG. 4A  is a cross-section view of an end for the linear temperature sensor cord shown in  FIG. 1A . 
           [0012]      FIG. 4B  illustrates a method of assembling the end shown in  FIG. 4A . 
           [0013]      FIG. 4C  is a cross-section view of a network juncture for coupling the ends of two of the temperature sensor cords shown in  FIG. 4A . 
           [0014]      FIG. 4D  is a cross-section view of a network manifold for coupling the ends of four of the temperature sensor cords shown in  FIG. 4A . 
           [0015]      FIGS. 5A and 5B  are cross-section views of boost initiators coupled to ends of the linear temperature sensor cord shown in  FIG. 1A . 
           [0016]      FIGS. 5C-5E  are perspective views of initiators, actuators and valves including one of the boost initiators shown in  FIGS. 5A or 5B . 
           [0017]      FIGS. 6A-6C  are schematic views showing embodiments including multiple linear temperature sensor cords coupled to multiple fire suppression medium sources. 
           [0018]      FIG. 7A  is a schematic view showing an embodiment including multiple linear temperature sensor cords coupled to multiple fire suppression medium sources and manual initiators. 
           [0019]      FIGS. 7B and 7C  are perspective views of manual initiators shown in  FIG. 7A . 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    The following describes embodiments of self contained fire extinguisher systems and methods of making and using self contained fire extinguisher systems in accordance with the present disclosure. Embodiments in accordance with the present disclosure are set forth in the following text to provide a thorough understanding and enabling description of a number of particular embodiments. Numerous specific details of various embodiments are described below with reference to self contained fire extinguisher systems on military vehicles, but embodiments can be used with other military, commercial or civilian vehicles, including terrestrial vehicles, marine vessels and aircraft. Embodiments of self contained fire extinguisher systems according to the present disclosure may also be used in static structures, e.g., kitchens. In some instances, well-known structures or operations are not shown, or are not described in detail to avoid obscuring aspects of the inventive subject matter associated with the accompanying disclosure. A person skilled in the art will understand, however, that the invention may have additional embodiments, or that the invention may be practiced without one or more of the specific details of the embodiments as shown and described. 
         [0021]      FIG. 1A  shows an embodiment of a linear temperature sensor cord  100  according to the present invention. The cord preferably includes a core  101  and a casing  102 . The core  101  is preferably a pyrotechnic blend of fuel and oxidizer powders with additives that result in a low auto-ignition temperature, for example, in a range of approximately 225 degrees Fahrenheit to approximately 800 degrees Fahrenheit. Generally, the range of auto-ignition temperatures is approximately 275 degrees Fahrenheit to approximately 680 degrees Fahrenheit, and preferably approximately 340 degrees Fahrenheit to approximately 400 degrees Fahrenheit. Test results have demonstrated that, in a typical diesel fuel fire and with the cord  100  spaced nominally 18 inches from the fuel, combustion of the cord  100  initiates in less than approximately 60 seconds. In addition to auto-igniting, the core  101  burns rapidly to provide a short response time, e.g., combustion propagates rapidly along the length of the cord  100 . Other embodiments according to the present disclosure may have cores  101  without additives. 
         [0022]    Embodiments of the cord  100  according to the present disclosure may have other constructions. For example, the casing  102  may include the fuel or the oxidizer and the core  101  may include the oxidizer or the fuel, respectively. Such a cord  100  may accordingly be consumed during combustion propagation. Other embodiments may include a pyrotechnic fluid core  101 , e.g., a liquid or gas, that may be disposed inside or applied, e.g., sprayed, dipped, etc., onto a casing  102 . Other embodiments according to the present disclosure may have other cores, e.g., a wick treated with a pyrotechnic fluid. 
         [0023]      FIG. 1B  illustrates a method for manufacturing the linear temperature sensor cord  100 . The casing  102  preferably includes a metal tube into which the pyrotechnic blend for the core  101  is loaded. The metal tubes may then pass thru dies, rollers, or other swaging devices to elongate the tube and reduce the diameter of the cord  100 . The tube material and properties may be selected for optimum thermal conductivity and tensile strength. Preferably, the diameter of the pyrotechnic core is selected for ensuring that combustion of the pyrotechnic core  101  propagates around bends formed in the cord  100 . The wall thickness may be pre-determined according to the swaging procedure. The walls of the casing  102  are preferably concentric with the longitudinal axis of the cord  100  and preferably have a consistent wall thickness. Preferably, the linear temperature sensor cord  100  can be easily bent by hand or by conventional tube bending tools and techniques to conform to a selected contour or path without crimping the cord  100 . 
         [0024]      FIGS. 10-1E  show arrangements of the linear temperature sensor cord  100  including features for adjusting sensitivity of the cord  100  to ambient temperature.  FIG. 10  shows the cord  100  including a flattened portion  110 ,  FIG. 1D  shows the cord  100  including a portion  120  having a cross-shaped cross-section, and  FIG. 1E  shows the cord  100  including a coiled portion  130 . The flattened portion  110 , the cross-shaped portion  120 , the coiled portion  130 , and other arrangements may provide the cord  100  with increased temperature sensitivity by increasing the surface area and/or thinning the wall of the casing  102 . 
         [0025]    Other embodiments according to the present disclosure may have casings  102  that include materials other than metal, e.g., natural fibers, polymers or other materials through which an elevated ambient temperature may be conveyed to auto-ignite the pyrotechnic core  101 . The casing  102  may also include a hybrid composition, e.g., metal fibers woven into a tubular cotton sleeve. Other manufacturing methods, e.g., extruding or weaving, may also be used for manufacturing the cord  100 . 
         [0026]      FIGS. 2A and 2B  show two embodiments according to the present disclosure for partially enclosing and protecting the linear temperature sensor cord  100 . In particular, it may be desirable to at least partially enclose the cord  100  to protect it from impact, abrasion or other damage in exposed areas and/or to shield the cord  100  in areas that do not require temperature sensing. The cord  100  can be inserted in a solid or perforated metal tube  202  or a non-metallic sheath  203  for protection. These protective coverings or shields may be implemented at intervals along the longitudinal axis of the cord  100 , thus leaving uncovered or exposed portions along the longitudinal axis of the cord  100 . Portions of the cord  100  that are covered with the sheath  203  may have reduced temperature sensitivity relative to the uncovered portions. It would therefore be preferable for sheaths  203  to be located along non-sensing lengths of the cord  100  for providing, for example, added impact or abrasion protection. The uncovered portions are preferably positioned in locations where it is desirable for the cord  100  to sense elevated ambient temperatures due to a fire. The tube  202  may provide impact protection substantially without adversely affecting the sensitivity of the cord  100 . For example, the thermal conductivity and/or perforations of the tube  202  may minimize any impediment that the tube  202  may cause to the cord  100  for sensing elevated temperatures due to a fire. Accordingly, the tube  202  and/or the sheath  203  may ruggedize or provide additional protection to portions of the cord  100  without compromising the sensitivity of other portions of the cord  100 . 
         [0027]      FIGS. 3A-3C  show attaching devices for supporting the linear temperature sensor cord  100 .  FIG. 3A  shows a resilient metal clip support device  301 ,  FIG. 3B  shows an elastically deformable elastomer support device  302 , and  FIG. 3C  shows a preformed or plastically deformable wire form support device  303 . The support devices  301 / 302 / 303  may support the cord relative to structures (not shown) in the temperature sensing areas. Variants of these support devices may also be used to support covered portions of the cord  100 , e.g., portions of the cord  100  covered by the tube  202  or the sheath  203 . 
         [0028]      FIG. 4A  shows a cup  401  enclosing an end of the linear temperature sensor cord  100 , and  FIG. 4B  illustrates a method of assembling the cup  401  onto the cord  100 . 
         [0029]    Preferably, the cup  401  includes a thin-walled metallic cup that is partially filled with additional pyrotechnic material  402 . The cup  401  preferably slides onto and seals the end of the cord  100 . The additional pyrotechnic material  402  may provide a booster to propagate the initiation signal across junctions or manifolds for networking plural cords  100 . 
         [0030]    The material for the cup  401  may the same or different from that of the casing  102 , and the additional pyrotechnic material  402  may be the same or different from that of the core  101 . Friction, adhesive, mechanical devices, or other coupling techniques may be used to temporarily or substantially permanently secure the cup  401  to the casing  102 . 
         [0031]      FIG. 4C  shows a network juncture  403   a  for coupling together ends of two temperature sensor cords  100 .  FIG. 4D  is a cross-section view of a network manifold  403   b  for coupling together ends of four temperature sensor cords  100 . Embodiments according to the present disclosure may include network couplings for three, five or more cords  100 , and may include any geometry that is suitable for propagating combustion across two or more ends. 
         [0032]      FIGS. 5A and 5B  show two embodiments of a boost initiator  500  that may be coupled at an output end of the linear sensor temperature cord  100 . The boost initiator boosts the combustion output of the cord  100  to (1) ignite a propellant fire suppression medium; (2) provide pressure to open a valve; or (3) provide pressure to puncture a sealing disc.  FIG. 5A  shows a pyrotechnic charge  501  that is initiated by the cord  100 . The size and material for the pyrotechnic charge  501  may be tailored to produce a selected quantity of pressure and/or heat, which may directly ignite a propellant type fire suppression medium, operate a valve, or rupture a sealing disc. The material for the pyrotechnic charge  501  may be the same or different from that of the core  101  and/or the additional pyrotechnic material  402 . 
         [0033]    Referring to the embodiment of the boost initiator  500  shown in  FIG. 5B , an integral metallic bulkhead  502  may be placed between two thermally sensitive charges, e.g., a donor charge  503  and a receptor charge  504 . The temperature of each charge is sufficient to transfer ignition across the bulkhead  502  without compromising the structural integrity of the bulkhead  502 . The size and material for the receptor charge  504  may be tailored to produce a selected quantity of pressure and/or heat  505 , which may directly ignite a propellant type fire suppression medium or operate a valve or rupture a sealing disc while maintaining a pressure seal across the bulkhead  502 . The material(s) for the donor and receptor charges  503 / 504  may be the same or different from that of the core  101  and/or the additional pyrotechnic material  402 . 
         [0034]    Embodiments according to the present disclosure may include several options for a fire suppression medium and its source. Fire suppression mediums may include, e.g., dry chemicals, liquids or inert gases. The sources for dry chemical and liquid fire suppression mediums are typically pressure vessels. Discharging these fire suppression mediums from pressure vessels typically includes opening a valve or rupturing a sealing disc. Inert gas fire suppression mediums are typically combustion products of a propellant that is not stored under pressure. Pressure from an inert gas fire suppression medium may be generated when the propellant is ignited and the resulting combustion produces a pressurized inert gas as the output. 
         [0035]      FIGS. 5C-5E  show embodiments of initiators, actuators and valves including one of the boost initiators  500 .  FIG. 5C  shows an inert gas generator propellant  510  that is initiated by the pyrotechnic charge  501 . Accordingly, an inert gas fire suppression medium is discharged via an outlet  512 , e.g., a nozzle, in response to the propellant  510  being ignited or initiated by the pyrotechnic charge  501 , which is preferably initiated by the linear sensor temperature cord  100  in response to sensing an elevated temperature that causes auto-ignition of the core  101 . 
         [0036]      FIG. 5D  shows an actuator for discharging a pressurized fire suppression medium  520 , e.g., a liquid or dry chemical fire suppression medium. The fire suppression medium  520  is discharged in response to the output of a boost initiator  500  displacing a piston  522 , which causes a sealing disc  524  to rupture thus allowing the pressurized fire suppression medium  520  to discharge through an outlet  526 . The boost initiator  500  is initiated by the linear sensor temperature cord  100  in response to sensing an elevated temperature that causes auto-ignition of the core  101 . 
         [0037]      FIG. 5E  shows a valve for discharging a pressurized fire suppression medium  530 . The fire suppression medium  530  is discharged in response to the output of a boost initiator  500  displacing a piston  532  relative to a valve body  534 . Preferably, this causes a shear nipple  536  to be lopped off thus allowing the pressurized fire suppression medium  530  to be discharged through an outlet  538 . The boost initiator  500  is initiated by the linear sensor temperature cord  100  in response to sensing an elevated temperature that causes auto-ignition of the core  101 . 
         [0038]    Embodiments according to the present disclosure may include other configurations and combinations of fire suppression medium sources, discharge controllers and boost initiators. For example, certain embodiments according to the present disclosure may eliminate the boost initiator if the output pressure and/or heat from the linear sensor temperature cord is sufficient to actuate the discharge controller. In lieu of an electrically operated system, auto-ignition of the core of the linear sensor temperature cord in response to sensing an elevated temperature causes the fire suppression medium to be discharged. Also, a network of the linear sensor temperature cords can be provided with different end configurations depending on the type of fire suppression medium and its source. 
         [0039]      FIGS. 6A-6C  schematically show examples of systems that include one or more of the linear temperature sensor cords  100  to initiate a propellant, puncture a disk, or activate a valve on one or more sources of the fire suppression mediums  510 / 520 / 530 . Preferably, the linear temperature sensor cord(s) connect to one or more inert gas generators. The cord(s)  100  can interface with a boost initiator  500  or directly with an igniter of the inert gas generator for initiating the propellant  510 . A solid inert gas generator propellant  510  may be preferable because it does not need to be stored in a pressurized cylinder and there is no residual material to remove or clean up after an inert gas discharge. 
         [0040]      FIG. 6A  shows six sources of one or more of the fire suppression mediums  510 / 520 / 530 . A plurality of the linear temperature sensor cords  100  (eight are shown in  FIG. 6A ) are coupled to sources or one another by network manifolds  403   b  (three are shown in  FIG. 6A ). In one embodiment according to the present disclosure, four of the six sources may be disposed in corresponding wheel wells of a vehicle and the two additional sources may be disposed proximate to the vehicle&#39;s running gear, e.g., in the engine compartment, battery compartment, etc. Core combustion is initiated when the ambient temperature exceeds the auto-ignition temperature of at least one of the cords. The networked cords and sources are accordingly initiated and the fire suppression medium(s) are discharged. 
         [0041]      FIG. 6B  shows one embodiment according to the present disclosure for providing a fire suppression system in a crew compartment of a vehicle. At least one linear temperature sensor cord  100  (seven are shown in  FIG. 6B ) is coupled to at least one source (six are shown in  FIG. 6B ) of a fire suppression medium  510 / 520 / 530 . The sources are preferably disposed inside a generally enclosed crew compartment and linked by networked cords for initiating the sources if the internal temperature exceeds the auto-ignition temperature. 
         [0042]    Additional networked cords (two are shown in  FIG. 6B ) may be used to also initiate the sources if a temperature external to the crew compartment exceeds the auto-ignition temperature. 
         [0043]    Certain embodiments according to the present disclosure may include implementing both the fire suppression system for the physical components ( FIG. 6A ) and the fire suppression system for the crew compartment ( FIG. 6B ) onboard a single vehicle as independent systems. Moreover, independent systems for additional compartments, e.g., cargo holds, fuel tanks, ammunition lockers, etc., may also be included on a single vehicle. An integrated fire suppression system for a single vehicle may include a network of linear temperature sensor cords that couple together all of the sources onboard the vehicle. 
         [0044]      FIG. 6C  shows an embodiment according to the present disclosure including a single length of the linear temperature sensor cord  100  and a single source of a fire suppression medium  510 / 520 / 530 . The single length may include a plurality of individual cords coupled in series by junctions (not shown). The linear temperature sensor cord may extend to several locations in a single compartment and/or may include portions extending into different spaces of a vehicle. Thermal insulators  600  disposed around portions of the cord  100  may provide impact protection and/or reduce sensitivity to elevated temperatures that are routinely anticipated, e.g., proximate an engine exhaust, and therefore do not represent a fire. Preferably, the single source may be dedicated to providing a fire suppression system at a particular location, e.g., a vehicle&#39;s driver seat, in response to threats of fire from multiple locations/spaces around the vehicle. One or more of these individual fire suppression systems may be used on a single vehicle, with or without a networked fire suppression system also being onboard the vehicle. 
         [0045]      FIG. 7A  schematically shows an embodiment according to the present disclosure of a fire suppression system  700  for a vehicle including a manual initiator  701  that can activate initiation the system  700  at any time or temperature. The system  700  preferably includes a plurality of networked linear temperature sensor cords  100  (only one is indicated in  FIG. 7A ), a plurality of sources of a fire suppression medium  510 / 520 / 530  (six sources including gas generator propellants  510   a - 510   f  are shown in  FIG. 7A ), and a plurality of manual initiators  701  (four manual initiators  701   a - 701   d  are shown in  FIG. 7A ). 
         [0046]    The sources of the fire suppression medium  510  are preferably distributed for discharging in the engine compartment  510   a / 510   b  and each of the wheel wells  510   c - 510   f . Alternate or additional sources may also be positioned in other locations on the vehicle. 
         [0047]    The manual initiator  701   a  is preferably located in the crew compartment of the vehicle, e.g., within reach of the driver. Alternate or additional manual initiators may be positioned around the exterior of the vehicle. For example, the manual initiator  701   b  may be positioned on the vehicle exterior, e.g., proximate an entrance to the crew compartment at the back of the vehicle, and/or manual initiators  701   c / 701   d  may be positioned on the either of the vehicle&#39;s exterior sides. 
         [0048]      FIGS. 7B and 7C  are perspective views of examples of the manual initiators  701  shown in  FIG. 7A .  FIG. 7B  shows an embodiment according to the present disclosure that includes a pull handle  702  for initiating the cord  100  coupled to the manual initiator  701  and  FIG. 7C  shows an embodiment according to the present disclosure that includes a rotary handle  703  for initiating the cord  100  coupled to the manual initiator  701 . In the event of a fire that does not reach the auto-ignition temperature, the manual initiators  701  can be manually activated. The manual initiators  701  are preferably positioned in non-hazardous areas and coupled to the sources of fire suppression medium  510 / 520 / 530  with the linear temperature sensor cords  100 . An example of a manual initiator is Part Number 813633-3 manufactured by Pacific Scientific Energetic Materials Co. (Hollister, Calif.). 
         [0049]    A method for suppressing a fire will now be described. Embodiments according to the present disclosure preferably include a linear temperature sensor cord  100  that, when exposed to a fire having a temperature that exceeds the auto-ignition temperature of the cord  100 , initiates combustion of the cord&#39;s core  101 . This core combustion propagates along the cord  100  to a source of a fire suppression medium  510 / 520 / 530  that is preferably positioned in a location to discharge the fire suppression medium  510 / 520 / 530  to suppress the fire. Core combustion may propagate in a network of the cords  100  to initiate or actuate one or more suppression medium sources. Likewise, individual suppression medium sources may be activated or initiated in response to core combustion from one or more of the cords  100 . Core combustion may provide adequate pressure and/or heat to activate or initiate the fire suppression medium source, or a boost initiator  500  may couple the cord  100  to the source for increasing the pressure and/or heat from the cord  100 , and thereby provide sufficient pressure and/or heat to activate or initiate the source. The fire suppression medium sources preferably include a propellant  510  that is initiated to produce a fire suppression medium, a pressurized fire suppression medium  520  that is released by rupturing a sealing disk, or a pressurized fire suppression medium  530  that is released by opening a valve. Embodiments according to the present disclosure discharging the fire suppression medium  510 / 520 / 530  without an electrical signal. Accordingly, a fire or damage that disrupts electric power or circuits will not in turn adversely affect the fire suppression performance of embodiments according to the present disclosure. 
         [0050]    A method of providing a fire suppression system onboard a vehicle will now be described. Embodiments according to the present disclosure preferably include a linear temperature sensor cord  100  that is routed into or through compartments or other locations on the vehicle such as engine compartments, crew compartments, wheel wells, fuel tanks, cargo holds, etc. The cord  100  may include an end positioned in a compartment or may include a loop or segment disposed in a compartment. Ends of the cord  100  are preferably enclosed by a cup  401 , coupled to a boost initiator  500  at a source of a fire suppression medium  510 / 520 / 530 , coupled directly to the source of the fire suppression medium  510 / 520 / 530 , coupled to one or more manual initiators  701 , or networked with one or more other cords  100  via a juncture  403   a  or a manifold  403   b.  Portions of the cord(s)  100  may be shielded from impact or abrasion with or without an appreciable effect on the temperature sensitivity of the cord  100 . For example, one or more portions of a cord  100  may be cinctured by a tube  202  or a sheath  203  with minimal impact on the ability of the cord  100 , and/or an insulator  600  may make one or more portions of the cord  100  less sensitive to the ambient temperature. Cords  100  may be bent or otherwise formed into shapes that follow a selected route and may be supported with respect to vehicle along that route by resilient clips, wires, etc. The route that the cord(s) follow may also extend on external surfaces of the vehicle. 
         [0051]    Embodiments according to the present disclosure may also be applicable to other environments such as kitchens, warehouses, or any structure in which it is preferable to provide fire suppression capabilities during electrical power outages. Embodiments according to the present disclosure may also be applicable anywhere electricity for a fire suppression system is not available. 
         [0052]    Embodiments according to the present disclosure may provide an elongated fire sensor rather than a conventional sensor that is located at a specific position and coupled by wires to a discharge controller. In contrast to these conventional sensors, the entire length of the linear temperature sensor cord  100  may provide fire sensing capabilities in addition to transmitting a signal to discharge a fire suppression medium. 
         [0053]    Embodiments according to the present disclosure may also be used to break an electrical circuit. For example, a fire in a particular space may be sensed by an embodiment of the cord according to the present disclosure. The cord may be disposed throughout the space rather than using a conventional sensor(s) disposed at discrete locations. In response to auto-igniting the cord, an embodiment of the boost initiator according to the present disclosure may cut electrical power to the space. 
         [0054]    From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications can be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited by the specific embodiments.