Abstract:
An apparatus and process for generating a pulsed high-speed fluid jet that can be used to extinguish fires and/or to launch a projectile. A valve, such as an instant on-off valve, preferably operates in combination with a pressure accumulator. In a controlled manner, a pulsed fluid jet is generated and directed through a nozzle. The nozzle can draw into the fluid-jet an additive. The nozzle may also be used to launch a projectile using the fluid jet as a propellant.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an apparatus and process for delivering a pulsed fluid jet that can be used to extinguish a fire, launch a projectile and/or perform other useful work. 
     2. Description of Prior Art 
     It is a well known fact that rapidly extinguishing uncontrolled fires can be a very difficult task due to the complex nature of present day fires and the associated urgency of saving lives or minimizing economic loss and environmental damage. Many different types of fire occur today because of a presence of many man-made materials that combust with unusual characteristics and extinguishing such fire rapidly requires unusual approaches. Worldwide cities are now more crowded than ever and more people are living inside high-rise buildings which also contributes to the problem. And yet, the available fire-fighting technologies have not appreciably changed over the years and are known to be inadequate in many ways. There is a demanding need for improved fire extinguishing processes. 
     One most common process for extinguishing fires is to pour water over a burning object. The basic scientific principle involved in extinguishing fire with water is to reduce a temperature of the burning object as each combustible material has its unique flammability temperature. A flame can be extinguished if the temperature of the burning object is reduced below a threshold temperature by wetting and cooling the burning object with water. However, the flame can resume when the water is evaporated and the object is again raised above this flammability threshold temperature. There are many materials, such as plastics, that are not water absorbent and that combust at very high temperatures or that combust in vapor form; water has very limited usefulness in extinguishing a fire of such materials. 
     Current water-based fire fighting processes also have shortcomings because of the delivery method. As a fluid, water flows down due to gravity such that its contact time with materials in a vertical, flowing downward, and inclined position is usually very short unless the spray is continuously applied over a period of time. The water spray is also often not powerful enough to travel a long distance, to reach a considerable height, or to break through common barriers such as windows, doors, roofs, and walls. In many cases, most of the water flows downward and is wasted. A good example is forest and bush fires in which a long contact time between the water and the burning branches is literally impossible to maintain, except by rain. Extinguishing common house fires within a house can be troublesome because of difficulties with pouring water into a house interior and onto burning surfaces. Fire can exist between the exterior walls and the interior walls or on ceilings, where water cannot be easily delivered into such space and onto such surfaces. As a result, much of the water consumed in fighting house fires causes water damage to the extent that even if a house is saved it is frequently damaged beyond repair. 
     A fire which occurs in a high-rise building is also a difficult fire to extinguish because of the difficulty in reaching the fire with water. Common sprinkler systems can be ineffective for various reasons. Likewise, fire which occurs at locations where water is scarce, or where fire equipment cannot be transported to the site, can be a problem where effective portable fire extinguishing equipment is unavailable. There are many other examples of ineffective currently available water-based fire fighting processes. Fires on oil storage tanks and on oceangoing oil tankers are very difficult to extinguish with conventional water processes. Airplane fires are another example of difficult fires to extinguish because of the presence of jet fuels and the large quantity of plastics materials. In some unusual cases, the water consumed in fighting fire can result in very severe environmental damage if it is not properly contained, as evidenced years ago in a fire that occurred in a chemical plant in Switzerland, in which the fire fighting water dissolved a large quantity of toxic chemicals and then flowed into the Rhine River and severely impacted the ecosystem of the Rhine River. 
     Since water is ineffective against certain types of fire and under certain conditions, more effective fire retardants have been developed and made available in various forms and packages over the years. These fire retardants, when released from their containers, can be in the form of a powder, a foam, or a liquid. They function in different ways and therefore should be used differently. Some produce inert gas such as carbon dioxide and nitrogen when they are heated, thus suffocating the fire; examples include sodium bicarbonate and azodicarbonamide. Others produce vapors that act as diluent and heat sinker to combusting gases or as a free radical trap that stops or slows flame propagation; examples include halogenated flame retardants. Still other fire retardants function on solid phase by forming a protective layer on combusting substances to inhibit heat transfer; examples include many phosphorous compounds. Then there are many common materials that are very effective fire retardant when they are spread over a burning object by isolating the burning object from the ambient air; examples include many earth minerals such as clay, alumina, and sand. These earth minerals are particularly effective when they are wet and impervious. There are also materials that are very absorbent to water and can swell to form a gel that can be very useful for extinguishing fires by acting as a wet blanket; examples include polyacrylamide polymers and copolymers, and some natural gums. All these materials have some very useful features that can be used to fight fires. 
     Unfortunately, the currently available processes involving the use of various fire retardants have a common shortcoming, namely poor delivery distance, accuracy, and coverage. For example, powders and foams are very light and they cannot be pumped easily or blown in air over a distance with any accuracy. Once delivered, powder and foam may have difficulty remaining on top of a burning object. For example, powder fire retardants are currently used to fight forest fires and are dropped from an airplane, with questionable effectiveness. Hand-operated fire extinguishers are effective only on small fires and in confined space because of limited delivery distance and light weight characteristics of the retardants. Sand is a good fire retardant, but there is no good way to throw sand over a distance. The currently available fire extinguishing processes based on fire retardants are also not powerful enough for breaking through barriers to reach interior fires. For example, the current practice of fighting ship fires is to spray water on the ship until it is virtually sunk. Therefore, to take advantage of the positive features of available fire retardants requires a more effective retardant delivery method. Further, a synergistic approach must be adopted to combine one or more materials to fight fires. For example, water can be used in conjunction with another fire retardant to create a slurry that can smear and stick to burning surfaces like a wet blanket rather than merely touch it which then flows downward. 
     SUMMARY OF THE INVENTION 
     One object of this invention is to provide an improved fire extinguishing process that combines the positive features of water and selected fire retardants with other suitable materials and devices to form a combination that can more effectively fight various types of fire, under a wide range of conditions. 
     Another object of this invention is to provide a process and apparatus that are useful for performing many other work tasks. 
     Another object of this invention is to provide an improved process and apparatus for extinguishing fire of many types. 
     Another object of this invention is to provide a process that uses a high-speed pulsed waterjet or other fluid jet to extinguish fires either by the fluid jet alone or in combination with selected fire retardants in various forms. 
     Another object of this invention is to provide an instant on-off valve useful in many fluid jet processes. 
     Still another object of this invention is to incorporate other selected materials or devices into the process to assist delivery of pulsed fluid jets and/or selected fire retardants and/or other materials that are useful in many other applications. 
     The process of this invention uses pressurization of a selected system fluid by a suitable pump or a source of compressed gas that is used to pressurize a system fluid inside a cylinder. The pressurized fluid is transported with a tube or hose into one or more energy storage devices in the form of a spring-powered or a gas-powered accumulator. The system fluid is stored inside an energy accumulator fluid chamber to a prescribed volume. The stored system fluid is ejected or discharged through one or more suitable instant on-off valves and nozzles to generate high-speed fluid jets on demand, and directing and delivering the fluid jet to a target. The selected system fluid can be water or other fluids, such as a pure liquid, an emulsion, a slurry, or a soft gel. The pump can be large or small, low pressure or high pressure, depending on the desired characteristics of the fluid jet. The pulsed fluid jet of this invention can be generated at a wide range of pressures, power input, frequency, and pulse durations by operating the energy accumulators and the on-off valves. The system equipment involved can be large and heavy, which of ten require mounting on a suitable chassis or carriage, or can be very portable that can be carried by a person, such as on a backpack. There can be multiple energy accumulators to a single pump, multiple on-off valves to a single energy accumulator, or multiple nozzles to a single on-off valve. The on-off valve used in this process is one important part of this invention. The nozzles on this process can be a simple fluid jet nozzle commonly used in water jetting applications or a compound nozzle that has components for introducing other substances into the fluid jet or to assist a fluid jet, such as during flight in air. The nozzles of the process of this invention may also be attached with a source of optical light or laser light, for the purpose of illuminating the fluid jet. 
     The process of this invention also uses a fluid jet to carry selected additives to assist extinguishing fire or doing other work. The additives can be added to the fluid prior to pressurization to form a mixture, a colloid, a soft gel, or a slurry and then introduced into the system equipment and eventually discharged or ejected out of the nozzle as a pulsed fluid jet. In an alternative embodiment of this invention, selected additives are introduced into the pulsed fluid jet in the nozzle chamber by utilizing a venturi effect generated by the fluid jet, or by loading the additives into the nozzle chamber by gravity, by pressure, or by other suitable mechanical means. The additives are preferably formed as a liquid, a slurry, a soft gel, a powder, or pellets that can be introduced into the fluid jet nozzle, preferably in a simple manner. In one embodiment of the pulsed fluid jet process of this invention, selected additives are time loaded into a nozzle chamber prior to issuing a pulsed jet. The fluid jet passes through the nozzle chamber and carries additives through a secondary nozzle to be shaped into a high-speed slurry jet. Thus, in this process there is proper energy transfer from the fluid jet to the additives. Such energy transfer is not proper or possible with a setup that uses continuous fluid jet. In fighting fires, the fluid jet of this invention can act as a carrier for the additives. 
     The process of this invention also use a special-effect device that is introduced into or onto the nozzle and ejected with or propelled by the pulsed fluid jet, for various suitable purposes. This device may be in the form of a ball, a bullet, a cap, a capsule, a cartridge, a shell, a tube or the like. This added device can be for shielding the pulsed fluid jet and/or the additives against the air during flight so that the fluid jet can travel much further, particularly with less dispersion. The added device can be packed with fire retardants and can be used or manufactured with fire retardants, to play an active role in fighting fires when propelled into a fire by the pulsed fluid jet. The added device of this invention can also be used as a piercing tool, allowing the retardants to be delivered into a closed space, such as a house, by breaking through barriers. The added device of this invention can also be installed with a valve or another material-releasing mechanism to perform special effects, such as releasing fire retardants to cover a large area. 
     The pulsed fluid jet of this invention is an ideal tool for propelling fire retardants because of the following reasons. 
     Water or another suitable liquid alone is or can be made to be an effective fire retardant. For example, carbon tetrachloride is a non-conductive and non-flammable liquid that can be useful in fighting an electrical fire, particularly when it is used in conjunction with conventional Halon powder. Water can be converted into a sticky soft gel with various additives such that it will smear a surface instead of flowing quickly down the surface. 
     Water or another suitable liquid can be pressurized to a high level and ejected or discharged through a nozzle to generate a pulsed jet that can be very fast and can pack considerable power which is particularly suitable for carrying additives. Air or gases, in contrast, cannot be used to generate a very fast jet and cannot be readily pressurized, due to its compressible nature. 
     Liquid having a specific gravity not too different from that of solid fire retardants allows a pulsed liquid jet to transfer energy more effectively to additives when compared to an air jet or a gas jet. 
     Waters and other selected liquid jets do not generate much heat in repeated operations and thus do not interfere with fire retardants. Explosives, on the other hand, cannot be used to propel many fire retardants due to the heat generated inside a tube, and the heat can set off the fire retardants. 
     The process of this invention also includes the use of a light source, such as laser light or other suitable optical lights, to illuminate a pulsed fluid jet issued from the nozzle for various purposes. 
     The process of this invention can be used also for delivering selected materials for other purposes, such as agricultural, environmental, and construction applications. For example, seeds, fertilizers, insecticides, and bioremediation reagents can be delivered effectively with the process and equipment of this invention. Soil stabilization materials can be blown over or injected into earth embankment, slopes, and ground with the process of this invention. Even seedlings can be propelled by pulsed fluid jet according to the process of this invention, and planted over a distance by using special capsules. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features of the apparatus and process according to this invention will be better understood when taken in view of the drawings, wherein: 
     FIG. 1 is a schematic view of an apparatus or a system for generating a pulsed fluid-jet, according to one preferred embodiment of this invention; 
     FIG. 2A is a graph showing an energy level versus time as related to the power according to a conventional pulsed fluid jet process; 
     FIG. 2B is a graph showing energy level versus time as related to the power of one preferred embodiment of this invention; 
     FIG. 3 is a cross-sectional view of an on-off valve, according to one preferred embodiment of this invention; 
     FIG. 4 is a cross-sectional view of a combination actuator and on-off valve, according to another preferred embodiment of this invention; 
     FIG. 5A is a cross-sectional view of a manually-operated actuator and on-off valve, according to another preferred embodiment of this invention; 
     FIG. 5B is a schematic view of a portable manually-operated apparatus, according to one preferred embodiment of this invention; 
     FIG. 6 is a cross-sectional view of a conventional venturi-effect fluid-jet nozzle, according to the prior art; 
     FIG. 7 is a cross-sectional view of a capsule or projectile, according to one preferred embodiment of this invention; and 
     FIG. 8 is a cross-sectional view of a capsule or projectile, according to another preferred embodiment of this invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to FIG. 1, one embodiment of this invention concerns a process for generating a pulsed fluid jet such as one that is useful for extinguishing fires and for many other tasks. The fluid can be water or any other suitable fluid, including slurries. The fluid is pressurized either by pump  1  that is powered by a motor or engine, or by a gas powered piston inside cylinder  2 , and is transported by a conduit, such as a tube or hose  3  through control valve  4  to accumulator  5 . Accumulator  5  is preferably, but not necessarily a cylindrical device having fluid chamber  6  and gas chamber  7  which is separated by piston  8  or straddled by piston-plunger assembly or plunger  9  that can slide within the chambers. Gas chamber  7  is filled with a pressurized gas, such as air or nitrogen, to a prescribed precharge pressure. Fluid chamber  6  is normally occupied by plunger  9 . When the pressurized system fluid enters into fluid chamber  6 , it forces plunger  9  against piston  8  to further compress the gas and to fill fluid chamber  6 . Fluid chamber  6  has outlet  10  leading to on-off valve  11  that is normally closed by valve poppet  12 . Valve  11  has outlet port  13  leading to fluid jet nozzle  14 . 
     In one preferred embodiment of this invention, valve  4  is an on-off valve comprising actuator  15  that can be operated by electrical, compressed air, hydraulic oil, or manual trigger power. Valve  11  comprises actuator  16  that is powered by electrical, compressed air, hydraulic fluid, or manual trigger power. When valve  4  is open and valve  11  is closed, the pressurized system fluid flows into fluid chamber  6  of the energy accumulator  5  and is stored there to a predetermined capacity. As a result, piston  8  inside gas chamber  7  is moved to compress the gas to a higher pressure, thus storing the energy. One or more piston position sensors  17  can be mounted inside or outside the cylinder of accumulator  5 , for example to monitor the exact location of piston  8  and to inform the controller if valve  11  should be opened. When valve  11  suddenly opens and valve  4  closes, the pressurized fluid inside fluid chamber  6  flows out valve port  13  and nozzle  14  to generate a high-speed fluid jet until fluid chamber  6  is emptied as plunger  9  pushes all fluid out of outlet  10 . Plunger cushion  18  which is preferably mounted inside fluid chamber  6  provides a fluid cushion to decelerate plunger  9 . Then, valve  11  closes and valve  4  opens to start another cycle. The presence of multiple piston position sensors  17  permits the variation of pulsejet duration and frequency. The valve operation can be handled manually or by means of controller  19 . On-off valve  4  protects pump  1  and can be omitted in some applications and the fluid will flow directly from the source to the energy accumulator  5  without interruption. Nozzle  14  of this invention can be a simple fluid nozzle or a complex nozzle, such as shown in FIG. 1, comprising additive inlet  20  for introducing to the fluid jet selected additives from storage hopper  21 , magazine  22  for storing and introducing special-effect devices  23  into nozzle chamber  24 , and/or a source of laser or optical light  25  attached to or near nozzle  14 . 
     In one preferred embodiment of this invention, the system fluid is water or a water-based liquid mixture, a soft gel, or a slurry. However, in other preferred embodiments the fluid is ethylene glycol, carbon tetrachloride, or other fluids that possess special properties advantageous to the applications. In large systems, the system fluid can be pressurized by suitable pumps and the valves operated with a controller. In portable systems, the system fluid can be pressurized with a manual pump or stored inside a cylinder that is pressurized by compressed air or gas and the valves can be operated by hand. The system fluid can be pressurized to a modest level of less than one hundred pounds per square inch (psi) or to tens of thousand psi, depending on the intended application. For systems operating at a modest pressure, accumulator  5  can comprise a simple cylinder having piston  8  inside for separating the system fluid from the compressed gas. In high-pressure systems, accumulator  5  is preferably constructed as a pressure vessel and has gas piston  8  and an attached fluid plunger  9 ; the diameter of piston  8  and plunger  9  is of a prescribed ratio, which determines a force relationship across the two components. The force generated by the system fluid inside fluid chamber  6  needs to overcome the force exerted on piston  8  by the compressed gas, in order to move piston  8  and to store the fluid energy. When valve  11  opens, the fluid jet is powered by the compressed gas pushing against piston  8  and plunger  9  and thus has power instantly and the power is continued until fluid chamber  6  is emptied and valve  11  closes. By manipulating or varying design and/or operating parameters of valves  4  and  11  and accumulator  5 , the pulsed fluid jet can vary in pulse duration and frequency. If pump  1  has variable pressure and flow control, then the power of the pulsed fluid jet can be varied as well. 
     For the pulsed fluid jet of this invention to function properly, it should have instant power and its power vs. time profile should follow a step curve rather than a bell curve, as shown in FIGS. 2A and 2B. In a bell-shaped curve profile as shown in FIG. 2A, the pulsed fluid jet would have fluid dripping at the beginning and end of a pulse due to a lack of energy. The dripping fluid does no work and is wasted. In a step-shaped curve profile as shown in FIG. 2B, the pulsed fluid jet, on the other hand, has instant power at the beginning of a pulse and plentiful power at the end of a pulse, thus wasting no fluid power. To produce such fluid jet pulse requires a suitable valve that provides instant on-off operations with a reasonably large outlet and with a fluid passage that is free of flow obstacles. Otherwise, a significant pressure drop and flow turbulence can occur which prevents the formation of a coherent high-speed fluid jet. In one preferred embodiment of this invention, an instant on-off valve is ideally suited for this process. 
     Referring to FIG. 3, instant on-off valve  100  of this invention comprises valve body  101  having central in-line cylindrical cavities  102  and  103  separated by partition  104  and seal  105 . Valve plunger  106  straddles across partition  104  and has front end  107  in chamber  102  and rear end  108  in chamber  103 . Valve seat  109  comprises a central valve port  1   10  shaped to mate with plunger front end  107  and in communication with valve outlet  111 . Valve inlet  112  passes through valve body  101  in communication with chamber  102 . Compression spring  113  around valve plunger  106  urges valve plunger  106  to move away from valve seat  109 . Valve actuating pin  114  has internal end  115  positioned inside chamber  103  and external end  116  positioned outside valve body  101 . Valve actuator  117  is attached to valve body  101  through adapter  118 . Valve plunger  106  has central through fluid passage  119 , check valve assembly  120  in line with fluid passage  119  that allows fluid to flow only from rear end  108  to front end  107 , and a smaller side fluid passage  121  linking chamber  102  to chamber  103 . Fluid passage  119  is in line with valve actuating pin  114  and can be closed or opened by internal end  115  of actuating pin  114 . Valve actuator  117  provides a necessary force to external end  116  of actuating pin  114 , directly or indirectly. 
     Still referring to FIG. 3, valve  100  in a normally-closed mode has an external force from valve actuator  117  pushing against actuating pin  114 , which in turn engages fluid passage  119  and pushes valve plunger  106  down to close valve port  110 . As pressurized fluid enters into valve chamber  102 , it is stopped by valve plunger  106  and a portion of this fluid flows through fluid passage  121  and fills chamber  103 , thus exerting force on plunger end  108  to close valve port  110 . In the meantime, the fluid force inside chamber  102  urges valve plunger  106  to part from valve seat  109  is comparably smaller due to the conical mating surface between plunger front end  107  and valve seat  109 , such that the fluid does not contact the central portion of valve plunger front end  107 . 
     To open valve  100 , actuator  117  is activated to allow actuating pin  114  to move away from chamber  103  and to expose fluid passage  119 , thus allowing pressurized fluid inside chamber  103  to flow through fluid passage  119  and into valve outlet  111 . As a result, the fluid force on plunger end  108  ceases and the fluid force inside chamber  102  pushes valve plunger  106  upward to expose valve port  110 . Being relatively smaller, fluid passage  121  delays the pressure equalization of chambers  102  and  103 , and check valve assembly  120  blocks the reverse flow of fluid from chamber  102  to chamber  103 , thus assuring that valve plunger  106  rapidly moves all the way up. Compression spring  113  also helps the upward motion of valve plunger  106  and keeps it at its highest position. Without check valve assembly  120 , valve plunger  106  may move up only part the way and then stop as the fluid pressure in chambers  102  and  103  equalizes, unless a powerful compression spring  113  is used to overcome seal friction around valve plunger  106 . In some embodiments of this invention, such powerful spring is not desired inside valve  100 . In normally-open mode of operation, valve  100  is identical except that actuator pin  114  is normally in disengaged position and the system fluid flows freely through valve  100 . To close valve  100 , actuator  117  is powered to push actuating pin  114  against valve plunger  106  and to close valve port  110 . Actuator  117  can have a piston-and-rod arrangement to provide the necessary force and can be powered by compressed air or gas and by pressurized oil. Actuator  117  can also be an electrical solenoid capable of push-pull operations. Actuator  117  can also be manually operated in which the required valve closing or opening force is provided either by a compression spring or by a hand-operated lever working against the spring. 
     Referring to FIG. 4, another instant on-off valve  200  of this invention comprises valve plunger  206  that serves dual purposes. Valve  200  comprises valve body  201  having three in line cylindrical chambers  202 ,  203  and  204 , separated by partitions and seals. Valve plunger  206  straddles across the three chambers  202 ,  203  and  204  and has front end  207  in chamber  202  and rear end  208  in chamber  204 . Valve seat  209  has valve port  210  in communication with valve outlet  211 . Valve inlet  212  passes through valve body  201  and is in communication with chamber  203 . Compression spring  213  around valve plunger  206  urges it to move away from valve seat  209 . Valve actuating pin  214  is in line with valve plunger  206  and has internal end  215  inside chamber  204  and external end  216  outside valve body  201  and in contact with valve actuator  217 . Side valve port  224  is in communication with chamber  202  to an external accumulator  205 . Valve plunger  206  has a central through fluid passage  219  with check valve assembly  220  near valve plunger front end  207 . A smaller side fluid passage  221  of valve plunger  206  is in communication with chambers  203  and  204 . Cutout area  222  around the middle portion of valve plunger  206  straddles across seal assembly  223 . The cutout area  222  serves as fluid passage from chamber  203  to chamber  202 , with a function similar to that taught in U.S. Pat. No. 5,297,777. 
     Still referring to FIG. 4, valve  200  of this invention combines two valves in one and represents the combination of valve  4  and valve  11  as shown in FIG.  1 . In normally-closed operation, valve  200  is closed and the system fluid flows through inlet  212 , chamber  203 , cutout area  222 , chamber  202 , valve port  224 , and into the fluid chamber of energy accumulator  205  and is stored there. In this closed position, cutout area  222  of valve plunger  206  is positioned across seal  223 , thus allowing the fluid to pass through cutout area  222 . When actuator  217  is energized to retract valve actuating pin  214 , valve plunger  206  moves away from valve seat  209  to open valve port  210  so that cutout area  222  moves to the right, as shown in FIG. 4, of seal  223  and into chamber  203 , thus preventing fluid flow from chamber  203  to chamber  202 . In the meantime, valve port  210  opens and the fluid stored inside accumulator  205  flows into chamber  202  and out of valve outlet  211  until the fluid chamber of accumulator  205  is emptied and valve  200  is closed again. Valve  200  allows separation of fluid flow so that clean pulsed fluid jets can be produced and the pump function not disturbed. If piston position sensor  227  is mounted on accumulator  205  and is connected to actuator  217 , valve  200  can be operated on an automatic repeat mode so that it will open as soon as the fluid chamber of accumulator  205  is filled to a prescribed volume and closes when the fluid chamber is empty. 
     The pulsed fluid jet process of this invention can be applied with a portable and manually-operated apparatus, such as shown in FIGS. 5A and 5B. The apparatus of this invention combines a relatively small energy accumulator with a manually-operated dual-function valve and a nozzle to form a complete pulsejet applicator  300 . With applicator  300  in a normally-closed position, hand lever  301  is pulled toward handle  302  to compress valve-actuating spring  303  and to move valve plunger  304  to open valve port  305 . When hand lever  301  is released and applicator  300  is closed, a pressurized system fluid flows from a pump or a pressurized tank through a hose to inlet  306  of applicator  300 . From inlet  306 , the fluid flows into valve chamber  307 , through cutout area  308  of valve plunger  304 , valve chamber  309 , side port  310 , fluid passage  311 , and into valve chamber  312  and fluid chamber  313  of energy accumulator  314 , which can be a separate unit or conveniently attached to the valves. Applicator  300  can have two valves, and front pulsejet valve  315  that controls valve port  305  in a way similar to valve  100  shown in FIG. 3, and rear valve  316  controls the inflow of system fluid to the energy accumulator. Together, valves  315  and  316  function as valve  200  shown in FIG.  4 . Applicator  300  has nozzle  317  in line with valve port  305 . Nozzle  317  can be a conventional fluid-jet nozzle employed in water jetting applications, or a complex fluid-jet nozzle having additive inlet  318  and detachable capsule magazine  319  for special-effect devices. Applicator  300  can provide a very compact hand-held pulsejet generator which can be used with a compact pump system or a pressurized fluid supply system. 
     When used in fighting fires, the system fluid such as water can be stored in a pressurized cylinder and can be carried on a backpack or on a small cart, and the selected fire retardants can be prepared in capsules and packed in magazines to be delivered by the pulsejets, or stored in another cylinder and delivered into the nozzle via a conduit, such as a hose. A venturi-effect fluid-jet nozzle allows energy to be transferred from the pulsejet to the additives and ejected together through a secondary nozzle. A suitable nozzle is taught by U.S. Pat. No. 4,666,083, and is illustrated in FIG. 6 of this invention. As shown in FIG. 6, this nozzle assembly has a high-pressure fluid-jet nozzle on the left and a secondary slurry nozzle on the right and therebetween a mixing chamber. The selected additives enter the mixing chamber through a feed tube in a side port and are often drawn or sucked into the nozzle by a vacuum generated by the very high speed fluid jet. The cited prior art taught the use of multiple orifices strategically positioned to provide superior energy transfer from the fluid jets to the additives and to generate a high-speed slurry jet. This prior art nozzle can be advantageously used in this invention. 
     The process of this invention also includes the use of a pulsed fluid jet to propel a selected object placed inside or outside a nozzle for various purposes. This object can be in many forms such as balls, bullets, caps, capsules, cartridges, cups, shells, and tubes, and is preferably loaded into a nozzle cavity by various means such as gravity, spring force, pneumatic power, mechanical means, or manual loading. The objects can be soft or hard, and made of various materials. FIG. 7 shows one preferred embodiment of the object wherein capsule  400  of this invention is shaped like a hollow bullet having an outer surface  401 , inner surface  402 , front head  403 , and interior cavity  404 . Capsule  400  can be molded from selected powder, formed from a gel, or can have an outer skin and an inner skin with other materials in between a powder and a gel. When the process of this invention is used to fight fires, capsule  400  can be made of fire retardants and be ejected out of a nozzle by a pulsed waterjet. Capsule  400  can deflect air resistance during flight and actively participate in extinguishing the fire. When capsule  400  is made of water absorbing polymers such as polyacrylamide, a pulsed waterjet swells the capsule further upon contact and together can be effective in blanketing a fire. Capsule  400  can be formed in so many ways such that they can be coded for use against fire of various types and under various conditions. 
     A pulsed fluid jet of this invention can generate so much force that capsule  400  can be made into a shell or bomb and shot or lopped into a fire by a pulsed fluid jet. Referring to FIG. 8, one embodiment of this invention is a fire-extinguishing shell  500  that has a cylindrical body  501  made of metal, glass, ceramic, or a hard plastic that can be propelled by a pulsejet of this invention. Shell  500  comprises rear cavity  502  for accepting a pulsed fluid jet, front cavity  503  containing liquid carbon dioxide or liquid carbon dioxide and other selected fire retardants, front impact valve  504  for releasing the contents of cavity  503 , and stabilizing fins  505  for improved air flight. Shell  500  is preferably loaded inside a cylindrical cavity in a pulsejet nozzle of this invention and is to be propelled by one pulsejet. Impact valve  504  opens rapidly upon impact, to release the fire retardants. Shell  500  can be made in various sizes and with different specialties to tackle fires of different natures. Shell  500  can also be made with very hard metal, so that it can pierce through barriers such as steel plate and deliver the fire retardants to the interior of vessels and tanks. Such capabilities are also very useful in fighting fire in high-rise buildings with a system mounted on a helicopter. 
     Referring back to FIG. 1, the apparatus of this invention may comprise more than one energy accumulator for each pump system to handle high flow of a system fluid, so that the flow is almost continuous. There can be multiple nozzle assemblies operating at a high frequency for each energy accumulator to deliver a large quantity of system fluid and additives to a target. Such capabilities are advantageous in fighting large fires with limited supply of water. The incorporation of water absorbing materials, in particular, will further improve the effectiveness of the process as the evaporation of water will be slowed down and nearly none of the water will be wasted. Once the flame is extinguished, the spread of fire will be arrested and cooling can begin. Bush and forest fires are examples of situations in which this invention will be useful. 
     The pulsed fluid-jet process of this invention has many applications other than fighting fires. A pulsed waterjet can find applications in display fountains and is particularly aesthetically pleasant if optical or laser light is incorporated to illuminate it at night. An acoustic effect of a powerful pulsed waterjet and the ability of this process in programming the pulsejet generation are other advantages in fountain applications. A high-power pulsed waterjet can be useful in many concrete demolition work and in mining/tunneling applications, even under submerged conditions. The process of this invention is also useful in many agricultural applications. For example, capsule  400  can contain seeds, plant nutrients, and water absorbents, and be delivered over a distance by pulsed waterjets. The water can be absorbed into capsule  400  and be used by seeds for germination. Such remote seeding process can be very beneficial in land reclamation and desert control. Even seedlings can be delivered over a distance and planted into ground by this process using a specially designed double-barreled capsule in which one barrel is for the seedling and the other barrel is for water and nutrients. A hand-held apparatus of this invention can be useful in such seedling planting operation.