Abstract:
A method and system for neutralizing mines has a vehicle carrying fluid connected to a pump and cavitation pressure vessel that creates high pressure fluid. An actuator valve modifies the flow characteristics of the high pressure fluid to be pulsating at selectively different frequencies, pressures, and flow rate. Nozzles on the vehicle jet high pressure fluid therethrough and a framework on the vehicle orients the nozzles to direct the jetted flow of high pressure fluid downward and into ground under a roadway. An abrasive and/or explosive can be added to the high pressure fluid before it reaches the nozzles. The jetted flow from the nozzles can displace ground and exert pressure to detonate and cut mines and neutralize them on and under the roadway. Cavitation can be created in the jetted flow to increase the dynamic force of the jetted flow.

Description:
STATEMENT OF GOVERNMENT INTEREST 
     The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor. 
     BACKGROUND OF THE INVENTION 
     This invention relates to systems for neutralizing ordnance. More particularly, this invention relates to a system that uses an array of downwardly aimed nozzles directing forceful, high pressure jets of fluid for clearing explosive obstacles including buried mines along an uninterrupted path and can survive mine-clearing operations. 
     Military and non-military agencies are still searching for a system that will effectively, reliably and safely de-mine roadway and off-roadway areas that are known or suspected to contain mechanical and electrical initiated mines. The basic requirement for an effective de-mining system is to detonate or disrupt either the mechanical or electrical firing train of each individual mine to effectively neutralize the mine. 
     Some military and non-military agencies already use a variety of means and apparatuses to clear areas of known/suspected mines on land and on roadways. Existing mine mitigation and neutralization systems have had some success, but current methods typically have major deficiencies that limit their intended capability. These limitations include high-cost, heavy weights, large sizes, difficulty of transportation, poor survivability from the explosions that these systems are intended to neutralize, logistical burdens, spare parts supply difficulties, etc. Currently none of these systems employ a concept of clearing mines with any type of water-jet technology. 
     Thus, in accordance with this inventive concept, a need has been recognized in the state of the art for a system for clearing surface and buried ordnance such as mines that uses an array of high-pressure fluid jets operating in several modes to destroy or disrupt the firing train of the ordnance without creating an undue risk of self-destruction. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     An object of the invention is to provide a mine neutralization system using cavitating water-jets and/or explosively augmented water-jets. 
     Another object of the invention is to provide a portable mine neutralization system adapted to fit on a variety of vehicles and operate over a variety of surfaces and soils for the purpose of mine mitigation. 
     Another object of the invention is to provide a mine neutralization system capable of resisting destruction or damage by detonating mines during their neutralization. 
     Another object of the invention is to provide a mine neutralization system that effectively destroys mines or neutralizes tactically buried mines along a path on a road or off-road, regardless of the surface or soil condition. 
     Another object of the invention is to provide a mine neutralization system adapted to fit multiple vehicles for mitigating threat to vehicles and personnel from mines scattered on a roadway. 
     Another object of the invention is to provide a mine neutralization system mounted on a motor vehicle for high-speed sweeping of scattered mines over a full width area on or off a roadway. 
     Another object of the invention is to provide a mine neutralization system that eliminates the cumbersome, expensive, and labor intensive limitations otherwise associated with contemporary mine neutralization systems. 
     Another object of the invention is to provide a safer and more effective mine neutralization system having reduced maintenance and spare parts requirements. 
     Another object of the invention is to provide a mine neutralization system having a variable depth of penetration and being tune-able to soil/road/hard pack conditions. 
     These and other objects of the invention will become more readily apparent from the ensuing specification when taken in conjunction with the appended claims. 
     Accordingly, the present invention is to a system and method for neutralizing mines. A vehicle provides transportation of this system on a roadway, and may have a fluid source for clearing operations. A pump on the vehicle partially raises the pressure of the fluid and a cavitation pressure vessel on the vehicle is connected to the pump to generate or raise the pressure of the fluid to high pressure. An actuator valve is coupled to the vessel to selectively modify the flow characteristics of the high pressure fluid to be pulsating at selectively different frequencies, pressures, and flow rates including continuous flow. At least one of a plurality of nozzles supported by the vehicle is coupled to the actuator valve to jet the flow of high pressure fluid to the nozzles. A framework on the vehicle is connected to the nozzles to orient them in order to direct the jetted flow of high pressure fluid downward and into the ground under the roadway. An abrasive additive unit may be coupled to receive the high pressure fluid from the actuator valve to add abrasive to the high pressure fluid before it reaches the nozzles. An explosive additive unit may be coupled to receive the high pressure fluid from the actuator valve to add explosive to the high pressure fluid before it reaches the nozzles. The jetted flow of the high pressure fluid from the nozzle can displace ground, exert pressure to detonate the mines, and cut parts of the mines to neutralize them on and under the roadway. The pump and cavitation pressure vessel are capable of raising the pressure of the high pressure fluid to cause cavitation in the jetted flow of high pressure fluid and increase the capability of the jetted flow of high pressure fluid to displace the ground, exert pressure to detonate the mines, and cut parts of the mines. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic side view, partially in cross section, of the mine neutralization system of the invention for jetting fluid into the ground to neutralize mines while reducing unwanted casualties and damage to a support vehicle. 
         FIG. 2  is a schematic, top view of the mine neutralization system of the invention of  FIG. 1  showing an exemplary arrangement of constituents thereof. 
         FIG. 3  is a schematic, block diagram of the fluid-pressure power module for supplying highly pressurized fluid for neutralizing mines. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIGS. 1 and 2 , mine neutralization system  10  of the invention is a mobile highly effective means for clearing mines  12  buried in and on the ground  13  along and/or around a roadway  14  intended for safe passage of men and vehicles. A support vehicle  16  tows an interconnected trailer  18  having a tank  20  or other source of water  22  or any other readily available suitable fluid that is used as a water/fluid supply for clearing operations. A water feed line  24  extends forward from tank  20  to provide water  22  to a high water/fluid pressure generating module  26 , see also  FIG. 3 . 
     Mine neutralization system  10  of the invention also allows combination of support vehicle  16 , trailer  18 , water-tank  20  with water  22 , feed line  24 , and high fluid pressure generating module  26  into a single heavy-duty truck or tracked vehicle or nearly any other means of locomotion at hand near the clearing site. These vehicles could be remotely controlled to further reduce the possibility of human casualties. Optionally, pressurized water  22  from a municipal water source can be coupled via an elongated feed line  24  to high fluid pressure generating module  26 . This inherent flexibility permits rapid deployment and application of mine neutralization system  10  wherever mine clearing operations are to be performed. 
     An array  28  of high pressure nozzles  30  is mounted on a forwardly extending framework  32  connected to support vehicle  16 . Framework  32  is connected to array  28  of nozzles  30  to direct or orient nozzles  30  to have water jets or jetted fluid  31  from nozzles  30  ejected in a downward direction toward roadway  14 . In accordance with long proven nozzle designs such as those developed for and used by gold mining and other water-jet technologies, individual ones of nozzles  30  can be made to each produce a water or fluid-jet  31  having the desired shape and mass-flow properties to transmit sufficient dynamic hydraulic forces to jet-away enough of ground  13  to expose and/or detonate mines  12 . Nozzles  30  can also be appropriately shaped to form jets  31  having sufficient concentrated force to slice through or cut-away parts of mines  12  and/or portions of their interconnected detonating trains to prevent them from detonating. In either case jets  31  from array  30  neutralize mines  12  buried in ground  13  under roadway  14  or lying on roadway  14  on ground  13 . 
     Array  28  of nozzles  30  is depicted in  FIG. 2  as being a single laterally aligned line array  28 A of nozzles  30  that extends the desired length to reach across roadway  14  and beyond the sides of roadway  14 .  FIG. 1  shows array  28  of nozzles  30  as being several adjacent line arrays  28 B of nozzles  30  that each extend the desired length to reach across roadway  14 . Arrays  28 B may have their nozzles  30  arranged in a laterally staggered fashion with respect to each other to assure more complete coverage across roadway  14  as support vehicle  16  travels forward on roadway  14 . Other arrangements of line arrays and nozzles  30  of array  28  can be made and used within the scope of this inventive concept. Mine neutralization system  10  can have only a single nozzle  30  jetting a single fluid-jet  31  or multiple nozzles  30  each ejecting a jet  31  that may be mounted on different array support structures or framework  32  that can be laterally expandable and/or retractable and can be designed to be wider than the tow or push vehicle  16  for wider lane clearance. 
     An essentially outwardly flared blast-deflection shield  34  having a shape similar to a reinforced snowplow blade also is mounted forward on support vehicle  16 . Framework  32  locates array  28  of nozzles  30  spaced-away in front of support vehicle  16  and above roadway  14  to direct jets  31  onto and into roadway  14 , and the reinforced blade of blast-deflection shield  34  is interposed between array  28  of nozzles  30  and support vehicle  16  to protect equipment and personnel in vehicle  16  from the effects of blast and fragments when mines  12  are detonated under nozzles  30 . 
     Array  28  of nozzles  30  is connected to receive a flow of highly-pressurized fluid/water, shown as arrow  38 , from fluid pressure generating module  26  over at least one high-pressure feeder line  40 . High pressure feeder line  40  can be connected to a manifold  42  to distribute highly pressurized water  38  to nozzles  30 . Optionally, a separate high pressure feeder line  40  extending from fluid pressure generating module  26  could be included for each nozzle  30  if, for example, different flow rates of highly-pressurized water  38  were wanted at different ones of nozzles  30  or if some of nozzles  30  were to be shut off during clearing operations to try to protect a strip of roadway  14  having, for example, a water or sewer line buried in the strip. 
     Referring also to  FIG. 3 , fluid pressure generating module  26  can have a high temperature heater  44  having a pair of valves  46  and  48  connected to feed line  24 . Valves  46  and  48  normally give a straight-through interconnection of water/fluid  22  to the rest of fluid pressure generating module  26 , but by appropriately switching valves  46  and  48  water  22  can be fed to and from heater  44  and then onto the rest of module  26 . Feeding water  22  to and from heater  44  provides the option of raising the temperature of water  22  up to and above boiling temperatures. Heated water  22  might be wanted for some clearing operations since heated water could increase the penetration or cavitation effects of fluid jets  31  from nozzles  30 . 
     Heated or unheated water  22  is drawn into fluid pressure generating module  26  from water supply tank  20  by a pump  50 . Control signals shown as arrow  52  from a control system  54  are generated by an operator in support vehicle  16  or by a suitably programmed and initiated computer in control system  54 . Control signals  52  are coupled to pump  50  to actuate it to draw in water  22  and couple it as water (shown as arrow  51 ) under high pressure to a high pressure feed line  56  that is connected to a cavitation pressure vessel  58 . 
     Pump  50  draws in water  22  from tank  20  at atmospheric pressure and creates highly pressurized water  51  at pressure levels approaching, for example, 4,000 bars. Pump  50  can be any one of several commercially available multi-stage models available in the art that are capable of creating highly pressurized water  51  in this range. 
     Pressurized water  51  in cavitation pressure vessel  58  is accumulated to reach increased pressure levels in sufficient volumes for mine clearing or neutralization operations. The pressure of pressurized water  51  will be raised further in pressure vessel  58  to create outputted water (shown by arrow  60  in high pressure line  62 ) at higher levels of pressurization, somewhere in the range between 13.7 Mpa and 68.5 Mpa. Highly pressurized water  60  is raised to this pressure range via vessel  58  in order to promulgate the formation of air bubbles in the fluid itself. Vessel  58  has a robustly built structure containing a chamber that meets the ASME pressure vessel code that several manufactures are capable of producing. Exemplary manufacturers of systems and components, including suitable pumps, pressure vessels, etc. that can be used for raising the pressure of fluids, stabilizing impulses from a pump, storing pressurized fluids, and providing sufficient volumes of pressurized fluid for neutralizing mines as called for herein, include but are not limited to: Pressure Products Industries Inc., Warmister, Pa. 18974; NLB corp., 29830 Beck Road Wixom, Mich.; and Sugino Machine Limited of Japan. 
     High pressurized water  60  is fed through high pressure line  62  to a first valve  64  that can be actuated by suitable control signals  52 A from control system  54  to pass high pressurized water  60  through a high pressure feed line  65  to a continuous or butterfly rotary/pulsating actuator valve  66  for selectively modifying flow properties of the high pressurized water  60 . Actuator valve  66  can incorporate an on/off flow device, which can be either an on/off via reciprocating or shutter-like device that opens and closes rapidly at selectively variable rates to create a flow (shown by arrow  67 ) of highly pressurized water to a high pressure feed line  68 . Actuator valve  66  can modify the flow characteristics of high pressurized water flow  67  to be continuous or pulsating at selectively different frequencies, pressures, and flow rates when control system  54  feeds suitable control signals (shown by the arrow  52 B) to actuator valve  66 . Optionally, when a pulsating flow is not needed, such as when a continuous flow is needed for some jetting away of some types of softer soil in ground  13  by jetted water  31 , control signals  52 B would activate actuator valve  66  to remain open so that water flow  67  might pass through as a continuous flow. 
     High pressure water flow  67  passes through a high pressure feed line  68  capable of containing flow  67 , and a pair of one-way check valves  70  and  72  are connected to feed line  68 . Check valve  70  is connected to a feed line  74  extending to a second valve, a control valve  76  having a feed line  78  extending to an abrasive additive unit  80 . Control valve  76  is selectively actuated by a control signal (shown as arrow  52 C) from control system  54  for selectively adding a powdered or liquefied abrasive composition or abrasive particulate slurry (shown as arrow  82 ) through feed lines  74  and  78  from abrasive additive unit  80  to high pressure water flow  67  in feed line  68 . Abrasive composition  82  in water flow  67  can enrich it to enhance the impact/penetration/cutting effects of fluid jets  31  as they are jetted into ground  13 . Abrasive additive unit  80  can be pressurized or have an injector mechanism to force passage of predetermined amounts of a variety of different kinds of commercially available abrasive compositions through feed lines  74  and  78 , through check valve  70  and into feed line  68  when control valve  76  is actuated by suitable control signals  52 C. Preferably, composition  82  is denser than water to further augment the impact/penetration/cutting effects of fluid jets  31 . 
       31 . 
     Check valve  72  is connected to a feed line  84  extending to a control valve  86  having a feed line  88  extending to explosive additive unit  90 . Control valve  86  is selectively actuated by a control signal (shown as arrow  52 D) from control system  54  for selectively adding a powdered or liquefied explosive composition or explosive particulate slurry (shown as arrow  92 ) through feed lines  84  and  88  from explosive additive unit  90  to high pressure water flow  67  in feed line  68 . Explosive composition  82  in water flow  67  can enrich pulsating water flow  67  to greatly increase the impact/penetration/cutting effects of fluid jets  31  since these explosive compositions are detonated as they are jetted from nozzles  30  into ground  13 . Explosive additive unit  90  can be pressurized or have a smooth running injector feed-mechanism to introduce predetermined amounts of different kinds of well known explosive compositions  92  through feed lines  88  and  84 , through check valve  72  and into feed line  68  when control valve  86  is actuated by suitable control signals  52 D. Typically, composition  92  might be the explosive Pentaerythritol Tetranitrate (PETN). PETN is the preferred composition because it requires very little energy for detonation and the grain size of the explosive material of composition  92  can be engineered to meet safety requirements for mine neutralization system  10  of the invention. Pulsation of the ejecta of jetted fluid of jets  31  via suitable actuation of actuator valve  66  prevents detonation effects of PETN explosive composition  92  from entering any of nozzles  30 . Other explosive compositions can also suggest themselves to one skilled in the art to arrive at the most effective and efficient combination for thorough mine clearing or neutralization operations. 
     An on/off control valve  94  in fluid pressure generating module  26  is located downstream of check valves  70  and  72 , and is actuated or controlled by a control signal (shown as arrow  52 E) from control module  54  to connect pure or enriched high pressure water flow  67  in high pressure feed line  68  to high pressure feeder line  40 . On/off control valve  94  also can have an externally reaching, manually operated lever  95  for cut-off or activation of fluid jets  31  from nozzles  30 . 
     Vessels including cavitation pressure vessel  58  and feed lines  24 ,  56 ,  62 ,  65 ,  68 ,  74 ,  78 ,  84 ,  88 , and  40  of mine neutralization system  10  have been used for many years to contain fluids at high pressures (greater than 70 MPa) in many industries such as cannon and small arms fabrication, polyethylene processing, materials processing and high pressure water jet cutting. In fact, many high pressure commercial applications routinely use vessels that operate at pressures reaching as high as about 400 MPa. However, some of these vessels, such as those used in polyethylene processing and water jet cutting, are subjected to high cycle fatigue loading. But, some weapons and some metals processing structures work with operating pressures that are as high as and even greater than 700 Mpa. Pressure vessels operating at or below the 700 Mpa range are not usually subjected to high cycle fatigue loading. Valves  64 ,  66 ,  76 ,  86 , and  94  also can be selected from a wide variety of commercially available valve structures. For example, appropriate ones of the valves marketed under the product line designation K-Max by Leslie Industries Inc., of Tampa, Fla. may be selected and used for the valve structures called for in mine neutralization system  10 . Accordingly, fabrication of high pressure structures for ducting fluids, as called for in the mine neutralization system  10  disclosed herein, can be done as a matter of routine by one having ordinary skill in the art. Mine neutralization system  10  of the invention can utilize different methods of water jet technology for the neutralization of mines  12  that can be referred to as fluid, fluid-solid, or fluid-solid-gas applications. A fluid only application utilizes a continuous water flow technique using continuous high pressure water flow  67  produced through actuator valve  66  of module  26 . Continuous water flow  67  is passed through valve  94  as flow  38  and is thrown out or ejected as continuous water flow jets  31  from nozzles  30  at the speed of about 3 to 4 times the speed of sound. In this case the pressure at pump  50  can be nearly as high as 4,000 bars, and system  10  is capable of processing (cutting through) raw materials such as ground  13 . 
     A variation of the fluid-only application utilizes a pulsed water flow technique having pulsating water flow  67  created by pulsating actuator valve  66  to create pulsating water flow  38  and pulsed water-jets  31  from nozzles  30 . The pulsed jets  31  fluctuate as compared to the continuous jet-flow from nozzles of the continuous flow technique. This pulsed flow of jets  31  has sufficient dynamic impact momentum on materials such as ground  13  and mines  12  to break them and provide for more efficient usage of water  22  than the continuous flow and, hence, better chances of neutralizing mines  12 . 
     The fluid-solid application or water-jet-and-abrasive-composition technique has portions of abrasive composition  82  injected into continuous water flow  67  to provide a continuous water flow  38  from valve  94  and jets  31  from nozzles  30  that are enriched with abrasive composition  82 . This abrasive-fluid mixture of jets  31  will jet away ground and other matter better because the abrasive material increases cutting ability as compared to cutting with high speed pure water alone. This technique utilizes one way valve  76  to inject and mix abrasive materials/compositions  82  with high-pressured water  67 ,  38  for ejection as jets  31  from nozzles  30 . This technique is commonly used to process materials that have high density such as glass, metal, ceramic and so on and can therefore be effective in clearing away dirt, aggregate, debris, etc. and cut apart or otherwise neutralize mines  13 . 
     Another application of water jet technology is the cavitating water technique that calls for the creation of cavitating jets  31  for impacting ground  13  and mines  12 . The combination of pump  50  and pressure vessel  58  is appropriately actuated to raise pressures of water flow  38  into the range between 13.7 Mpa and 68.5 Mpa. Pressures in this range create air bubbles in water flow  38  that are formed physically in the fluid to create a working fluid having a higher impact effect on the dirt, aggregate, debris, etc. of ground  13  and mines  12  by jets  31 . The switching stresses created by the cavitating air bubbles of fluid jets  31  as they form, expand, and impact create higher levels of compression and tension in the exited water of fluid jets  31  to break the material of ground  13  and mines  12 . The water flow  67  created by actuator valve  66  for the purpose of creating cavitation of jetted fluid  31  can be either continuous or pulsating. Adding abrasive  82  creates the fluid-solid-gas application referred to above. 
     The synergistic advantages of mine neutralization system  10  of the invention in its application of the techniques of water-jet technology are realized when several parameters are combined to achieve increased efficiency in mine clearing operations. Those parameters consist of utilizing: continuous water-jet, abrasive water-jet, pulsed water-jet and/or cavitating water-jet techniques in combination with abrasive additive compounds  82  and/or explosive additive compositions  92 . The continuous water flow technique utilizes pump  50  to produce pressures approaching almost 4,000 bars to provide continuous pressurized water flow  38  at a speed of almost 4 times the speed of sound. Adding the cavitating water-jet technique also makes use of vessel  58  to raise pressures to the range between 13.7 Mpa and 68.5 Mpa where air bubbles are physically formed in fluid  38 . This causes impacting jets  31  of system  10  to have even higher impact since the cavitating process enhances the material breaking process. Adding abrasive compositions  82  can further enhance effectiveness by increasing the capability to cut through ground  13  and mines  12 . Adding explosive composition  92  further increases the effectiveness of mine neutralization system  10  since adding explosive components to the water flow  38  assures that system  10  effectively mitigates mines  12  through forced detonation/burning and fracture of mines  12  to sterilize or make them safe. 
     Mine neutralization system  10  of the invention can either cut up mines  12  or detonate the mines by augmenting the cutting abilities of water jets  31  that jet-away ground  13  and parts of mines  12 . By adding to or enriching the pulsating water flow of water-jets  31  with an explosive composition  92  that will react exothermically under the high pressure of target impact by jets  31 , increased neutralization effectiveness at and in ground  13  will result. Since the constituents of system  10  are spaced a safe distance away and above ground  13 , system  10  is designed to survive the detonations that it induces. In other words system  10  effectively mitigates mines  12  without being damaged or destroyed in the de-mining/mitigation process. 
     Insertion of abrasive compositions  82  from abrasive additive unit  80  and explosive compositions  92  from explosive additive unit  90  can be combined with the continuous water-jet, abrasive water-jet pulsed water-jet, or cavitating water-jet created by the techniques described above. The inserted compositions increase efficiency in some tough clearing operations that may be found in stubborn aggregate and/or clay laden soil compositions in ground  13  and/or tough casings for mines  12 . 
     Mine neutralization system  10  of the invention can utilize or fit on different vehicles to provide a means to effectively mitigate the threat to vehicles and personnel from mines scattered on or off roadway  14 . Mine neutralization system  10  creates a motorized means for high-speed sweeping of mines  12  that are scattered on or off a full width area of roadway  14  or buried beneath it. Mine neutralization system  10  eliminates bulky and expensive conventional systems that are cumbersome and labor intensive, and provides a much more effective and safe system with reduced maintenance and spare parts requirements. Mine neutralization system  10  provides for the neutralization of mines  12  at variable depths of penetration in ground  13  and is tunable to successfully neutralize mines  12  in different conditions of soil/road/hard pack. 
     Having the teachings of this invention in mind, modifications and alternate embodiments of mine neutralization system  10  may be adapted without departing from the scope of the invention. Its uncomplicated, compact design that incorporates structures long proven to operate successfully lends itself to numerous modifications to permit its reliable use under the hostile and demanding conditions routinely encountered during combat in the field. Mine neutralization system  10  can be fabricated in different physical arrangements from a wide variety of materials that have sufficient strengths and properties to reliably perform under a multitude of different operational conditions. Mine neutralization system  10  of the invention can be modified within the scope of this inventive concept to provide an effective piece of equipment that can be modularized for storage and adaptation to a support vehicle  16  for neutralizing mines  12  without incurring unwanted casualties and other collateral damage. 
     The disclosed components, and their arrangements as disclosed herein, all contribute to the novel features of this invention. Mine neutralization system  10  provides a reliable and capable means of neutralizing mines  12  while preventing unwanted casualties and other collateral damage. Therefore, mine neutralization system  10 , as specifically described herein is not to be construed as limiting, but rather, is intended to be demonstrative of this inventive concept. 
     It should be readily understood that many modifications and variations of the present invention are possible within the purview of the claimed invention. It should also be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.