Abstract:
A method and apparatus for subjecting a material in a liquid to explosive forces is provided. The method and apparatus involve a vessel having a length greater than it width. The vessel has a top which is quickly and easily lockable and removable so as to increase the material processing rate of the vessel.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     This invention relates to using explosive forces generated inside a contained environment to subject materials to extremely high pressure. Examples include a process of breaking apart cellulose fibers and the removal of lignin in connection with the wood pulp industry and the hardening of materials, such as metals. 
     2. Description of Related Art 
     Currently the wood pulp industry uses chemical steam processing and mechanical grinding and milling to break apart cellulose fibers and remove lignin. These processes use an excess of energy, can take a long period of time, and use environmentally unfriendly chemicals. 
     Chemically produced pulps are processed in digesters by a sulfite or kraft process. Digesters can be designed for batch or continuous flow. 
     The sulfite pulping mechanism utilizes the raw materials sulfurous acid and either sodium, magnesium, or calcium bisulfate as the two main ingredients to process the lignin within the wood chips. The sulfurous acid works as a catalyst and breaks the ether linkages in the lignin molecule. Then, the sulfite ions bond to the open sites on the lignin molecules to aid in the lignin dissolution. A high temperature and long cook time are required for these reactions to have successful rates and yields. Normal operating conditions for batch sulfite pulping include a digester temperature of 150° C. with a cook time of four hours. 
     One problem with the sulfite mechanism is that the sulfurous acid acts on the carbohydrates in the fiber. The more carbohydrates that are lost, the weaker the pulp becomes and the weaker the resulting dried paper product will be. The sulfite cook actually leaves about 4% of the original lignin in the chip to reduce the chance of losing any extra carbohydrates. 
     The kraft pulping method eliminates the need for sulfurous acid as a raw material. Instead, the raw materials are sodium hydroxide and sodium sulfide. Sodium sulfide can double the rate of delignification over the sulfite process; hence the kraft process is the dominant process in the industry. The mechanics of kraft reactions are similar to those of sulfite reactions. In this case, the OH-ions from the sodium hydroxide will break the lignin ether linkages. Once broken, the hydrosulfide ions (SH—) can bond with the open lignin sites to react with methyl groups and form methyl mercaptans. Methyl mercaptans contribute to the unique odor associated with kraft pulping. 
     The kraft pulping process leaves more lignin with the digested pulp than the sulfite process. The main reason for this is that the OH—ions can more easily penetrate the crystalline cellulose walls and break down the carbohydrates than can the sulfurous acid ions. Usually about 8% of the original lignin stays with the chips. 
     During the past decade, the paper industry has seen a significant increase in the percentage of secondary fibers used to make up the paper machine furnish (secondary fibers=OCC—old corrugated containers, MOW—mixed office waste, etc.). In fact, almost all newsprint and an increasing number of tissue and medium board machines are going to 100% recycled fibers for their funish. 
     A problem most mills encounter when changing over to recycled fibers from a virgin chemically pulped furnish is a reduction in fiber strength and size. When a mill decides to implement a recycled fiber program, a new recycled fiber plant is usually constructed in order to repulp the recycled products and to remove undesirable contaminants that are introduced to the system from the recycled materials (i.e. latexes, coatings, inks, glues, waxes, oils, etc.). These contaminants can destroy a mills production rate if not efficiently removed in the recycling plant. Hence, a successful recycle fiber plant will take previously made papers and boxes and efficiently deliver to the paper machines the cleanest and strongest pulp possible. The characteristics of each batch of recycled pulp will have a dramatic effect on the efficiency of the paper machines. 
     Fibers that have already been used to make a box or piece of paper are inherently weaker than virgin fibers. These fibers have already been subjected to refining, high temperature dryer cans, press loading, etc., which take away from their size and strength. The main way to strengthen a recycled fiber is to re-swell and then mechanically refine the fiber. The swelling is done with water and pH control (wood fibers-are hydrophilic and will accept water). Once the fibers are swollen they can be refined in order to fibrillate the fibers. Fibrillation is when a single fiber is subjected to mechanical forces that cause fibrils to branch off of the original fiber. This action will increase the surface area of the fiber, which will form a stronger mat on the paper machine wire. Swelling and refining also help open up the hydroxyl sites on the fiber and fibrils, which increases the chance of hydrogen bonding between the fibers. Hydrogen bonding is essential for a strong finished sheet of paper. 
     U.S. Pat. Nos. 5,273,766 and 5,328,403 disclose a tank for tenderizing meat in which the meat is supported along a hemispherical wall of the tank and then subjected to a shock wave produced by an explosive charge. The tank disclosed in these two patents is specifically hemispherical in shape and therefore the amount of meat processed by the tank per explosive charge is limited to the amount of meat that can be supported along the hemispherical wall of the tank. To increase the amount of meat processed per explosive charge, the radius of the hemisphere that defines the shape of the tank must be increased, greatly increasing the volume of water required to fill the tank. It is well known that for a given surface area a sphere has the greatest volume of any shape. 
     SUMMARY OF THE INVENTION 
     The invention provides an elongated tank for containing explosive forces. The elongated tank of the invention provides better results than the tank disclosed in U.S. Pat. Nos. 5,273,766 and 5,328,403 due to its elongated shape. The elongated shape of the tank of the invention more efficiently subjects the material in the tank to the explosive forces than does the spherical shape of the tank in U.S. Pat. Nos. 5,273,766 and 5,328,403. In addition, for a given volume of liquid/water, more material can be processed in the elongated tank of the invention because it is not spherical in shape. 
     An embodiment of the invention has a vessel having a vessel-top and a vessel-bottom. A liquid containing the material, for example wood chips, to be subjected to the explosive forces is held in the vessel-bottom. The vessel-top is positioned such that the explosive forces are substantially contained within the vessel-bottom and vessel-top. The material is subjected to pressure waves in the water created by the explosive forces. The explosive forces can, for example, be provided by an explosive, such as PETN, or by capacitor discharge through electrodes in the vessel-bottom. 
     The invention can greatly reduce the amounts of energy, chemicals, and/or time required to process certain materials. 
     For example, the invention can greatly reduce the amounts of energy, chemicals and time required to process and tear down the cellulose fibers and remove lignin in the wood pulp industry. By introducing a delignification vessel into the current process flow, either before or after the digesters, the process efficiency of chemical pulping can be increased. The delignification vessel of the invention subjects wood chips, for example, to explosive forces transmitted through water or other liquid. The resulting extremely high pressure causes the liquid to penetrate the wood chips to extract the undesired lignin component. The explosive forces can be generated by any means such as, for example, an explosive charge or capacitor discharge. 
     The vessel can be integrated into a recycled fiber plant to help soften/swell the fibers during repulping and to aid in the release/removal of the undesirable contaminants being introduced with materials such as papers and boxes. By detonating a submerged charge of explosive, a plant could very cost effectively swell the fibers with good water penetration, fibrillate the fibers with very high-pressure forces, and release inks, latex, coatings and other undesirable contaminants by subjecting them to the high pressures of the detonation wave. 
     Successful integration of the vessel of the invention could relate to huge savings in a mill&#39;s operating costs. Stronger pulps may result than are produced by the current refining methods (because of the reduction in cutting by the refmers) or a simple reduction in the amount of refining needed and reduced power consumption may result. Hence the mill could increase its percentage use of recycled fiber, resulting in financial and environmental benefits. Also, with better contaminant release from the fibers, the recycle plant could see much higher efficiency with its screens, centrifugal cleaners, clarifiers, etc., and hopefully reduce the amount of equipment needed. Chemical consumption for contaminant control would also be greatly reduced with more efficient removal in the plant. 
     Another example of an application of the invention is in the hardening of metals, such as, for example, hardening the exterior layer of metal golf club heads, axes, chisels and other tools. Such a hardening process could allow the use of cheaper metals, as compared to the currently popular titanium, while still providing a hard surface for superior performance. In this application, the metal to be hardened can be held in place within the vessel-bottom by, for example, support wires or stands, or simply laid on a bed of sand placed in the vessel-bottom. The metal is hardened by being subjected to the pressure waves created in the liquid by the explosive forces. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be described in relation to the following drawings in which like reference numerals refer to like elements, and wherein: 
     FIG. 1 is an end view of an embodiment of the invention; 
     FIG. 2 is a perspective view of the vessel-top of an embodiment of the invention; 
     FIG. 3 is a side view of the vessel-top of FIG. 2; 
     FIG. 4 is a perspective view of the vessel-bottom of an embodiment of the invention; 
     FIG. 5 is a side view of the vessel-bottom of FIG. 4; 
     FIG. 6 is a sectional view of the vessel-bottom of FIGS. 4 and 5 along section line VI—VI of FIG. 5; 
     FIG. 7 is a simplified perspective view of a mass production facility incorporating the invention; 
     FIG. 8 is an end view of an embodiment of the invention in which the vessel-bottom is rigidly held in position; 
     FIG. 9 is a sectional side view of an embodiment of the vessel-bottom of the invention shown in the closed position; 
     FIG. 10 is a sectional side view of the embodiment shown in FIG. 9 shown in an open position; 
     FIG. 11 is a top view of the vessel-bottom of an embodiment of the invention using capacitor discharge; 
     FIG. 12 is a sectional side view of the vessel-bottom of the embodiment shown in FIG. 11 taken along section line XII—XII; 
     FIG. 13 is a cross-sectional view along section line XIII—XIII of the semi-cylindrical shaped vessel-bottom of FIG. 14; and 
     FIG. 14 is an end view of the embodiment shown in FIG.  13 . 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The invention provides a cost effective process for altering the properties of materials through subjecting the materials to extremely high pressures. 
     The invention increases the process efficiency of chemical pulping by introducing a vessel into the current process flow before the digesters. The invention can be applied to both batch and continuous flow digesters. 
     The invention will be discussed using an explosive charge, but other means of generating explosive forces within the liquid can be used. 
     FIG. 1 shows vessel  5  as an example of an embodiment of the invention. Vessel  5  includes vessel-top  10  and vessel-bottom  20 . The vessel-top in this example is removable and can be lifted from the vessel-bottom with, for example, pneumatic or hydraulic cylinders or a hoist. Vessel-top  10  is shown in more detail in FIGS. 2 and 3. Vessel-top  10  includes vessel-top flanges  12  having top flange holes  14 . In this example, each vessel-top flange  12  has six top flange holes  14  but can have more or fewer top flange holes  14  as needed. The number of top flange holes  14  required is determined based on the length of the top vessel  10 , the forces acting on the top vessel  10  as a result of the explosive charge and the strength of top bolts  50  (described below). 
     An example of the vessel-bottom  20  is shown in more detail in FIGS.  4 - 6 . Vessel-bottom  20  includes vessel-bottom flanges  22  having bottom flange holes  24 . In this example, each vessel-bottom flange  22  has six bottom flange holes  24 . However, similarly to the vessel-top flanges  12 , the vessel-bottom flanges  22  can have more or fewer bottom flange holes  24  depending on the length of bottom vessel  20 , the forces resulting from the explosive charge and the strength of bottom bolts  60  (discussed below). Bottom vessel  20  includes, for example, eyeholes  26  for holding a hanging wire  2  on which the explosive charge  1  is held. Hooks or other holding members can be used for holding the explosive charge in position. 
     An example of the material used for the vessel-top  10  and the vessel-bottom  20  is mild steel or stainless steel 2″-4″ thick. The lower sides  28  of the vessel-bottom  20  are sloped with relation to the bottom  29  of the vessel-bottom  20 . This shape has proven more effective than a hemispherical shape vessel-bottom. In addition, sloped lower sides  28  are preferred to a rectangular cross-section in order to reduce the stresses in the joints between the lower sides  28  and the bottom  29 . While this shape is used as an example, the vessel-bottom could also be formed in a semi-cylindrical shape (as shown in FIGS.  13  and  14 ). 
     In the embodiment shown in FIG. 1, the vessel-bottom  20  is held in position by bottom bolts  60  which are embedded into and held in position by foundation liner  40 . The foundation liner should be made from a strong material such as, for example, steel in order to securely hold bottom bolts  60  in place. Vessel-bottom flanges  22  are positioned between top springs  90  and bottom springs  92 . Top springs  90  and bottom springs  92  are, for example between 8″ and 12″ in diameter, preferably 10″ in diameter, and have spring rates of between 10,000 lbs/in and 50,000 lbs/in, preferably 20,000 lbs/in. Washers  94  are located at each end of each top spring  90  and each bottom spring  92 . A nut  62  is used to hold each assembly of washers  94 , top spring  90 , vessel-bottom flange  22  and bottom spring  92  in position on each bottom bolt  60 . The example of vessel-bottom  20  shown in FIGS.  4 - 6  would have  12  such assemblies. In this embodiment, the vessel-bottom  20  is held in position such that it does not contact foundation liner  40  at any time before, during or after detonation of the explosive charge. Foundation liner  40  can be positioned in the bottom of a trench  110  formed in a foundation  44 . 
     One example of a process of the invention is to fill vessel-bottom  20  to a desired level with a liquid, such as, for example, water, place the hanging wire  2  in place using the eyeholes  26 , then submerge the wood chips into the liquid. Although eyeholes  26  are used in this example, it is noted that any appropriate holding device, such as, for example, hooks, can also be used. An explosive charge  1  is then run along the hanging wire  2  and is connected to an initiation device (not shown) such as, for example, a blasting cap, or capable of being detonated by non-physical contact methods such as, for example, radio or ultrasonic signals. The vessel-top  10  is then placed and secured on the foundation  44 . The explosive charge is preferably below the surface of the liquid when detonated. An example of the explosive charge is 0.25-5 lbs. of PETN detonated by a blasting cap of #8 strength or higher. 
     Top bolts  50 , each having a bolt head  52 , are embedded in and held by foundation  44 . The vessel-top  10  is lowered into position such that each bolt head  52  passes through a top flange hole  14  and a round portion  34  of a locking plate hole  32  in a locking plate  30 . A locking plate  30  is attached to the vessel-top  10  and located above each vessel-top flange  12 . Locking plate holes  32  are located in locking plates  30  and, in this example, each have a round portion  34  and a slot  36  as shown in FIG.  2 . The locking plates  30  are attached to the vessel-top  10  by locking plate positioners  38 . The locking plates  30  are initially positioned such that the round portions  34  of the locking plate holes  32  are lined up with the top flange holes  14 . Round portion  34  of each locking plate hole  32  is large enough to allow bolt head  52  to pass therethrough. After the vessel-top  10  is lowered into position over top bolts  50  so that bolt heads  52  extend above locking plates  30  (as shown in FIG.  3 ), locking plates  30  are moved by locking plate positioners so that slots  36  of locking plate holes  32  are positioned around top bolts  50  and immediately below bolt heads  52 . Because the bolt heads  52  are too large to pass through the slots  36 , the vessel-top  10  cannot be lifted off of the top bolts  50  when the locking plates  30  are in this position. 
     The above-described locking mechanism is made strong enough to keep the vessel-top  10  from moving when subjected to the forces resulting from the explosive charge. This locking mechanism is one example of a structure that provides sufficient locking of the vessel-top  10  and also allows quick unlocking and removal of the vessel-top  10 . 
     A ridge vent  70  is provided as a part of the vessel-top  10  in order to allow explosive gases to escape from the vessel  5 . FIG. 2 shows an example of ridge vent  70  having a ridge vent roof  72  attached to the vessel-top  10  by ridge vent roof supports  74 . The ridge vent roof  72  is located above vent holes  76  in, in this example, a top portion of the vessel-top  10 . FIGS. 1 and 3 show a deflector  78  positioned below vent holes  76 . Deflector  78  prevents liquid forced upward by the explosion from shooting directly through vent holes  76 . Ridge vent roof  72  deflects downward any liquid or other matter passing through vent holes  76 . 
     Upon initiation of the explosive charge, the wood chips are exposed to extremely high pressures created by the designed vessel boundaries as well as the liquid. Currently, the pressures range from 5,000 psi to near 100,000 psi at the explosive interface. However, it is conceivable that higher pressures will be available with future explosives. The pressure is great enough to penetrate wood chip cell walls and extract the undesired lignin component. Also the high pressure should create some positive defibrillation results on the cellulose fibers. 
     By introducing the vessel  5  before or after the digester, the required amount of the products mentioned above should be greatly reduced. For instance, the amount of raw material Na 2 S and NaOH should be reduced for kraft pulping and the amount of sulfurous acid and bisulfate compound should be reduced for sulfite pulps. Also the amount of sulfide compound by-products should be reduced, the amount of time the digester is held at high temperatures should be reduced, the workload on the chemical recovery systems should be lessened, and the workload on the digesters themselves should be reduced. 
     Wood chips possess entrained air, which retards the removal of lignin in the cooking process. Pulping mills presteam the chips before they are introduced to the digester to remove the undesired air. The vessel  5  can reduce or eliminate steam usage by exposing the chips to extremely high pressures to force out entrained air. 
     Defibrillating the cellulose fibers will be beneficial. The high pressures create some positive defibrillation on the cellulose fibers. Therefore, the mill can experience reductions in time and money associated with the beaters and refiners, as well. 
     There are variables used to define the desired size of charge to achieve optimal lignin removal and cellulose defibrillation. The liquid temperature in the vessel is limited only by its boiling point. When water is used as the liquid, the liquid temperature range is preferably between 32° F. and 212° F., and more preferably between 70° F. and 190° F. In addition, the distance between the explosive charge and the wood chips can be varied to achieve anywhere from 5,000 psi to near 100,000 psi at the explosive interface, preferably between 5,000 psi and 50,000 psi. If the explosive charge is detonated above the surface of the liquid, the pressures can be reduced by increasing the distance above the surface of the liquid at which the explosive charge is detonated. If the explosive charge is detonated below the surface of the liquid, or if capacitor discharge is used, the material, for example wood chips, can be separated and held away from the explosive interface by a mesh or other retaining structure. An example of the retaining structure is retaining mesh  130  shown in FIG.  6 . In this example, retaining mesh  130  is held in place by retaining mesh restraints  132 . By using a retaining structure to control the distance between the explosive charge and the material, the pressure to which the material is subjected can be controlled. When water is used as the liquid, the addition of small quantities of Na 2 S, for example a sufficient quantity to produce 0-25% sulfidity, to the water can prove very beneficial to the lignin removal. 
     If the vessel is used to process the material after the material exits the digester, chemicals present in the material can be used advantageously when the material is subjected to the high pressures in the vessel. Similarly, the material can be subjected to the high pressures in the vessel at any stage of processing. Due to the existence of particular chemicals in the material at certain stages of processing, it may be determined that subjecting the material to the high pressures in the vessel at a particular stage is advantageous. For example, it may be advantageous to subject the material to the high pressures in the vessel before the brown stock washers. 
     The length of the vessel may be varied to achieve maximum wood chip poundage per explosive discharge, hence governing the hourly output. 
     An example of using capacitor discharge as the source of the explosive forces is shown in FIGS. 11 and 12. In this example, vessel-bottom  20 ′ has electrodes  150  positioned in its bottom  29 . A capacitor discharge machine  152  is connected to the electrodes  150  by wires  154  and a power source (not shown). The electrodes  150  can be furnished in any appropriate number and can also be positioned on portions of the vessel-bottom  20 ′ other than the bottom  29 . As water and wood chips, for example, pass by the electrodes  150 , the electrodes  150  can be fired as quickly as 3 times per second. By using capacitor discharge, there is no need to open the vessel to replace the explosive charge. 
     The example shown in FIGS. 11 and 12 is a vessel without an inlet or outlet. However, the capacitor discharge process can be applied to a vessel having an inlet  160  and an outlet  161  as shown, for example, in dotted lines in FIGS. 11 and 12. In a vessel having an inlet  160  and an outlet  161  as shown in FIGS. 11 and 12, the liquid containing the material to be subjected to the explosive forces continuously flows into the vessel through inlet  160  and out of the vessel through outlet  161 . The electrodes are repeatedly fired at a rate that subjects the material to the required forces as the material flows by the electrodes. A vessel according to this example allows a continuous flow of treated material without removal of the vessel-top. An embodiment of such a vessel has protective members  140  that cover the inlet  160  and outlet  161  at the moment in time when the electrodes are fired. Such protective members can be, for example, reciprocating sliding plates that are synchronized with the electrodes or rotating circular plates having alternating solid and open segments such that a solid segment covers the inlet/outlet when the electrodes are fired. 
     The continuous treatment of material described above can also be achieved by placing capacitor discharge electrodes at various positions within the wall of a pipe (instead of the vessel described above) and passing the material laden liquid through the pipe and past the electrodes. 
     FIG. 7 shows an application of the invention directed to a high level of output in a commercial processing plant. In this example, multiple (5) trenches  110  are provided in a plant floor  120 . Each trench  110  contains a vessel-bottom  20  and mounting structure as, for example, shown in FIG.  1 . One vessel-top  10  is provided. In this example, a first trench  110  is prepared with liquid, material to be processed (for example, wood chips) and an explosive charge. The vessel-top  10  is then positioned and locked in place and the explosive charge is detonated. The vessel-top  10  is then unlocked, removed from the first trench  110 , positioned on a second trench  110  (previously prepared) and locked in place. The explosive charge is then detonated in the second trench  110 . While the explosive charge is being detonated in any particular trench  110 , the other trenches  110  can be emptied and prepared for another detonation. This type of system is beneficial because it requires only one vessel-top  10  for a plurality of trenches  110 . As the vessel-top  10  is made from steel or other high strength material, and is repeatedly subjected to explosive forces, it is an expensive part of the vessel  5 . As a result, a system, such as this one, that permits an increased number of detonations per vessel-top  10  is more cost effective. Although this example uses five trenches  110  arranged in parallel to each other and one vessel-top  10 , it is noted that the number and position of trenches  110  and the number of vessel-tops  10  used would be optimized by taking into consideration the amount of time needed to empty and prepare a trench  110  and the amount of time required to unlock, remove, relocate and lock a vessel-top  10  in position. It is anticipated that the optimum combination of these factors would result in the vessel-top  10  being continually moved from trench to trench, being in position above any particular trench only as long as required to safely detonate the explosive charge. 
     While the example of the vessel-bottom  20  shown in FIG. 1 is resiliently held in position by top springs  90  and bottom springs  92 , it is also possible to rigidly hold vessel-bottom  20  in position so that it does not move relative to foundation liner  40  when subjected to the detonation of the explosive charge (as shown in FIG.  8 ). In this embodiment, the foundation liner  40  can be made from a material such as concrete or sand. 
     In the previous examples, the material within the vessel-bottom  20  after detonation can be removed by, for example, either scooping or pumping. FIGS. 9 and 10 show an embodiment of the invention in which one end of the vessel-bottom  20  is a sliding panel  210  having a lifting hook  212 . The sliding panel  210  slides vertically within a slot  220  formed in the vessel-bottom  220 . The sliding panel  210  and slot  220  abut end wall  230  of the vessel-bottom  20  in order to eliminate or minimize the forces to which slot  220  is subjected during detonation. A pipe  240  is attached to end wall  230  so that when, after detonation, sliding panel  210  is lifted upward, the liquid  3  containing the processed material flows out of the vessel-bottom  20  under the force of gravity. 
     The invention should greatly reduce the time, energy, raw chemical usage and emissions presently required and produced by the wood pulp processing industry. 
     Another application of the invention involves the hardening of metals for use in, for example, golf club heads. The process is preferably performed before the club head is attached to the hozzle and shaft. The club head is placed into the vessel and, through explosives or a process such as capacitor-discharge, is subjected to great pressure. The pressure greatly hardens only the outer layer of the club head due to the reflective pressure wave bouncing off of it. The increased hardness can increase the distance that a golf ball travels when hit by the club. The process can be done for numerous club heads at one time to reduce the unit cost of the process. 
     The hardening process can also be applied to other metal objects in which hardness is a desired characteristic. Such other objects may include, for example, cutting tools such as drill bits and saw blades and weapon components such as gun barrels, firing pins, trigger components and mounting bases. 
     Other processes can be achieved by the invention such as adding flame retardant materials to wood, other pressure treatments of wood, or other processes in which one material (usually a fluid or suspended in a fluid) is forced into or through another material (usually a solid). In these processes, the explosive charge is used as the source of pressure to force the one material into or through the other material. Other examples of the many possible uses of the invention include explosive art work, adding imprints to steel, killing microbes, pathogens and bacteria, and breaking down waste materials quickly for, for example, recycling. In these examples, the material is subjected to the explosive forces (either in liquid or in a gas, such as, for example, air) inside the vessel. 
     While the invention has been described in conjunction with the specific embodiments described above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the embodiments of the invention as set forth above are intended to be illustrative and not limiting. Various changes may be made without departing from the spirit and scope of the invention as defined herein. For example, other materials, such as food, leather, denim jeans and other fibers, can be subjected to the explosive forces in the vessel to cause softening of the materials.