Patent Abstract:
A process and apparatus wherein multiple instantaneous pressure pulsations with a regulated frequency and amplitude are applied to various biological substances in order to eliminate the undesired microorganisms in these substances with minimal negative effect on the quality of these substances, and, further, to use these in mass production of foodstuffs pharmaceuticals for treatment of human blood or plasma, and for research to establish a specific frequency of pressure pulsations at which a particular type of bacteria could be selectively destroyed while other components of the substance remain intact.

Full Description:
REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a non-provisional application of U.S. of co pending Provisional Application conformation No. 7469, filed Jul. 18, 2006 by the same inventor and entitled MICROBIAL INACTIVATION BY MULTIPLE PRESSURE SPIKES DELIVERED WITH REGULATED FREQUENCY. 
       BACKGROUND OF THE INVENTION 
       [0002]    Many different methods are used to inactivate harmful microorganisms in the pharmaceutical industry, food processing, medicine, and biotechnology. One method, most often used for liquid substances, is a method used in conventional thermal processing. In this method, the temperature of the liquid is kept elevated for a period of time, and higher temperatures usually required shorter time duration to produce the necessary results. In the food industry, however, this method has an adverse effect on flavor, vitamin, and protein content of the final product. 
         [0003]    In the biotech industry, millions of genetically engineered, protein-producing  E. coli  bacteria are added to a nutrient-rich growth medium for the mass production of therapeutic proteins. After the bacteria synthesize the desired product, they are pumped into a high pressure tank, where they remain for a period of time under extremely high pressure until their cell walls burst open, releasing the contents. In some instances, a successful outcome requires that the process be repeated several times. This method is also used in the production of juices and other food products. The advantage of the high pressure treatment, as compared to the more popular heat treatment, is that this method inactivates the microorganisms with minimal harm to vitamins or flavoring. However, this method has a number of shortcomings, especially in the area of economic feasibility and engineering limitations. Economic feasibility is limited by the high cost of capital investment for the equipment, low productivity, and the high labor cost of batch process. Economic feasibility is further limited by the long process time, 30 minutes to 1 hour, which is required by some applications. Engineering limitations include concerns about the construction of high pressure vessels with a large enough capacity to hold substantial quantities of product. 
         [0004]    In another method used to inactivate microorganisms, the liquid substance is first pressurized and then depressurized by transferring the liquid into an area of reduced pressure through one or more constrictions, as shown in U.S. Pat. No. 6,120,732. This method is based on the principle that bacteria cannot withstand sudden pressure change and substantial mechanical friction. However, passage of a substantial quantity of liquid substance through a small orifice with high speed results in overheating of the orifice due to friction, and leads, in liquids such as milk, to the buildup of a hard substance (milk stone) on the tip of the orifice. The formation of such “milk stone” has a negative effect on the process and often can even block the orifice completely. Other problems include limited throughput and the difficulty of maintaining the liquid under high pressure in a vessel, from which a substantial volume of liquid escapes to the low pressure vessel. These problems render this method impractical for the mass production. Finally, since, in the most cases, the percentage of inactivated bacteria is insufficient, additional treatments are often required to achieve acceptable results. 
         [0005]    In another method, a special restrictive nozzle is used in place of an orifice. As in the above method, a partial inactivation of the bacteria is achieved by both sudden pressure drop and mechanical friction. In addition, the restrictive nozzle causes the atomization, or break-up, of the liquid substance into tiny particles. The atomized product is then treated with steam vapor. In this treatment, the atomized particles, when coming into contact with vapor, undergo a sudden temperature rise in addition to the sudden pressure drop. The sudden temperature rise further enhances the inactivation of bacteria. In order to keep the maximum temperature of the treated product down, the vapor temperature would need to be no more then 50-60 degrees Celsius. This is achieved by the introduction of vacuum into the system, as shown in the U.S. Pat. No. 6,277,610. This method, however, does not eliminate the “milk stone” problem or the problem of controlling the product temperature after the nozzle. The difference between the temperature of “cold steam” and the temperature of treated substance is often not substantial enough to effectively inactivate the bacteria. To make this process work, the temperature of the steam would have to be raised, which in turn would adversely affect the quality of the final product. 
       SUMMARY OF THE INVENTION 
       [0006]    It is an object of this invention to provide a method for the purpose of killing harmful microorganisms in various substances with minimal negative effects on the overall quality of these substances. 
         [0007]    It is another object of this invention to provide a method for the purpose of killing harmful microorganisms in various substances to be used in mass production and to be cost and energy efficient. 
         [0008]    It is yet another object of this invention to provide a device that generates instantaneous pressure changes with adjustable amplitudes and frequencies in various substances for the purpose of researching an optimal combination of these parameters in the process of killing harmful microorganisms in these substances. 
         [0009]    It is yet another object of this invention to provide a device that generates instantaneous pressure changes with adjustable amplitudes for the purpose of selecting the most economically effective combination of pressure amplitude and time duration needed to decrease the quantity of harmful microorganisms to an acceptable level. 
         [0010]    It is another object of this invention to provide a device in which the frequency of the instantaneous pressure changes is adjustable for the purpose of researching frequencies most effective in killing bacteria. 
         [0011]    It is yet another object of this invention to provide a device to be used in mass production of foodstuffs or therapeutic medication, in which a specific frequency of pressure vibrations is applied to selectively kill certain type of bacteria. 
         [0012]    It is yet another object of this invention to provide an energy efficient method for the use in mass production of foodstuffs and medication. The existing methods require either instantaneous heating or cooling of mass quantities of product, or the forcing of mass quantities of product through small orifices under high pressure. Such processes require massive amounts of energy. The process described in present invention, however, is energy efficient due to the fact that pressure spikes are applied to a substance stored in a closed container without necessitating movement of mass or additional heating or cooling of the substance. 
         [0013]    It is well established that extreme conditions, such as high temperature, high pressure, and mechanical friction, facilitate the killing of harmful microorganisms. However, some of these conditions, such as temperature and friction, affect the quality of the product negatively and others, such as high pressure, are too costly for the process to be economically practical for mass production. It is also known that rapid changes in temperature and pressure may be used to facilitate the destruction of harmful microorganisms. Although these methods allow the lowering of process temperature while at the same time preserving the quality of the final product, they are too cumbersome to be effectively controlled and economically feasible. The need to move large quantities of substance through a restrictive nozzle in a short period of time, while at the same time maintaining high pressure in front of the nozzle, renders these methods impractical for mass production. In addition, these methods do not deliver reliable results in killing bacteria and also have a problem with the build-up of hard substance in the orifice of the restrictive nozzle, which blocks the nozzle altogether. 
         [0014]    In accordance with an aspect of present invention, a multitude of instantaneous pressure changes (pulsations) is applied to various substances for a period of time for the purpose of inactivating harmful microorganisms. The percentage of killed bacteria will increase with the increase either in the frequency or the amplitude of pressure pulsations. Both of these parameters are easily regulated and controlled in present invention and the most economically effective parameters that would produce the least negative effect on the final product can be easily researched. 
         [0015]    Furthermore, the novelty of the present invention is in its ability to apply pulses of pressure to the treated substances with a wide range of different frequencies. Every time the substance is pressurized, the outer membrane of the bacteria cell will contract while the internal pressure of the membrane will rise to equalize the outside pressure. Every time the outside pressure is removed, the internal cell pressure will expand the outer shell. Due to inertia and elasticity, the outer shell will also over-expand slightly beyond its original size. As a result, the internal forces in the outer shell will rise and bring the outer shell back to its original size. Normally, these expansions and contractions of the outer shell occur with a specific “natural” frequency. During regular application of pressure spikes, the bacteria vibrate with the frequency of the applied pressure spikes. When the frequency of pressure spikes coincides with the natural frequency of the bacteria cells, a resonance occurs, which increases the amplitude of cell vibrations with each pressure pulsation until the outer membrane bursts and the bacteria is destroyed. In summary, the application of pressure pulsations with frequencies equal or close to the natural frequency of a particular microorganism accomplishes the selective killing of these microorganisms without negative effect, on the final product. 
         [0016]    The invention accordingly is comprised of the features of construction, combination of elements, and arrangements of parts that will be exemplified in the system, device, and article of manufacture hereinafter described, and of which the scope of application is as elucidated hereinafter, as will be indicated in the appended claims. In this regard, numerous alternatives within the scope of the present invention, besides those alternatives, preferred embodiments or modes practicing the invention supra, and those to be elucidated, will occur to those skilled in the art. 
         [0017]    Other objects, features and advantages of the invention in its details of construction and arrangements of parts will be seen from the above, from the following description of the preferred embodiment when considered with the drawing and from appended claims. In addition, these and other objects and advantages of the present invention will become evident from the description which follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a cross-sectional view of a system incorporating present invention where a high pressure hydraulic cylinder with a rotary valve is employed to deliver intermittent high pressure spikes with a regulated frequency to the liquid substance contained in the vessel for the purpose of killing harmful microorganisms in the substance. 
           [0019]      FIG. 2  is a cross-sectional view of a system incorporating present invention where a high pressure hydraulic cylinder controlled by a directional control valve is employed to deliver intermittent high pressure spikes to the liquid substance contained in the vessel for the purpose of killing bacteria in the substance, and, where a three-way directional control valve is used to facilitate the movement of the cylinder&#39;s piston rod in and out of the vessel. 
           [0020]      FIG. 3  is a cross-sectional view of present invention where air pressure is used in a cylinder to generate multiple pressure spikes for the purpose of killing harmful microorganisms in the liquid substance contained in the vessel. 
           [0021]      FIG. 4  is a cross-sectional view of a system incorporating present invention where two pumps with pressure-regulating and directional valves are added to automatically load and unload the liquid substance to facilitate continuous manufacturing process. 
           [0022]      FIG. 5  is a cross-sectional view of a system incorporating present invention where a rotating mechanical cam is incorporated to produce instantaneous pressure pulsations in the liquid substance contained in the vessel. 
           [0023]      FIG. 6  is a cross-sectional view of present invention where a rotating wheel with a number of actuators, formed on the outer diameter of the wheel, is incorporated to generate high frequency pressure pulsations in the liquid substance contained in the vessel. 
           [0024]      FIG. 7  is a cross-sectional view of present invention where an ultrasonic frequency generator is employed to produce pressure pulsations in liquid substance contained in the vessel. 
           [0025]      FIG. 8  is a cross-sectional view of present invention, where a solid product, suspended in liquid, is treated to inactivate the harmful microorganisms by instantaneous pressure pulsations. 
           [0026]      FIG. 9  is a cross-sectional view of present invention, where a cooling jacket is formed around the vessel to facilitate cooling of the liquid substance contained in the vessel during pulsating pressure treatment. 
           [0027]      FIG. 10  is a cross-sectional view of present invention, where a heat exchanger is incorporated into the system to facilitate the cooling of the liquid substance contained in the vessel during pulsating pressure treatment. 
           [0028]      FIG. 11  is a cross-sectional view of present invention, where a cylinder is made to alternate between the generation of pressure pulsations in the substance contained in the high pressure vessel and the pumping of the substance from the first vessel to the second vessel through a restriction. 
           [0029]      FIG. 12  is a cross-sectional view of present invention to be used in mass production, where one pulsating pressure-generating device is used to treat multiple containers filled with substance, which are moving on a conveyer. 
           [0030]      FIG. 13  is a cross-sectional view of present invention, where an air-hydraulic pressure buster and a hydraulic cylinder are used to produce high pressure pulsations in the liquid substance stored in the container. 
           [0031]      FIG. 14  is a cross-sectional view of present invention, where inactivation of harmful bacteria in a liquid substance and homogenization processes are combined in one apparatus comprising of a container with the pressure pulsation generating device and the homogenizing device formed on the opposite sides of the container. 
           [0032]      FIG. 15  is a cross-sectional view of present invention, where inactivation of harmful bacteria and homogenization processes are combined in one apparatus, in which both high pressure pulsation and homogenization treatment of the substance are done by one cylinder. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0033]    With reference to  FIG. 1 , there is generally shown a cross sectional view of a system incorporating present invention. Vessel  1 , containing substance under treatment  2 , is placed on bottom plate  4  of stand  3 . Stand  3  consists of plates  4  and  5  connected by columns  6 . Columns  6  are formed to support the load induced by cylinder  7 . Cylinder  7  is mounted to the top plate  5  by bolts  8 . The cylinder&#39;s piston rod  10  is inserted into neck  11  of vessel  1 . High pressure seal  13  is formed at the end of piston rod  10 . Piston rod  10  is in contact with the treated substance  2 . The volume above piston  9  in cylinder  7  is filled with oil and is connected to rotary valve  14 . Rotary valve  14  consists of valve housing  15  and rotor  17 . Rotor  17  is formed with two sealed chambers  16 . Rotor  17  is connected through axle  21  to a motor with an adjustable speed rotation. Three openings, “a”, “b”, and “c”, are formed in valve housing  15 . Opening “a” is connected to the piston side of cylinder  7 . Opening “b” is connected to tank  18 , while opening “c”, through pressure-regulating valve  19 , is connected to high pressure pump  20 . During the rotation of rotor  17 , chambers  16  periodically connect the piston area of cylinder  7  to either low pressure tank port “b” or high pressure port “c”, thus intermittently changing the pressure on the piston side of cylinder  7 . The oil pressure is regulated by pressure-regulating valve  19 . The pressure applied to the substance depends on the diameter of cylinder  7  and the diameter of piston rod  10 . Because piston rod  10  is always in contact with substance  2 , high pressure in substance  2  is generated instantly. By changing the rotating speed of rotor  17 , one can easily control the frequency of the pressure spikes delivered to substance  2  inside vessel  1 . 
         [0034]    With reference to  FIG. 2 , there is generally shown a cross section of another system, incorporating present invention. In this system, however, the rotating valve is replaced by directional control valve  22  with controlling solenoid  23 . Depending on its position, valve  22  connects the volume above piston  9  either to the pressure port or to the tank port. Controlling solenoid  23  receives an “on” or “of” signal intermittently, with a controlled frequency, thus delivering pressure pulsations with the same frequency to substance  2  in container  1 . Directional control valve  24  is added to facilitate the movement of piston rod  10  in and out of vessel neck  11 . When valve  24  shifts to the right, the system pressure reaches the inlet port of valve  22  and when valve  22  is in its right position, piston rod  10  extends into neck  11  of vessel  1 . When both valves  24  and  22  shift to the left, piston rod  10  retracts from the neck  11 . 
         [0035]    With reference to  FIG. 3 , there is generally shown a cross section of another system incorporating present invention. In this system, however, air pressure is incorporated to produce the pulsating pressure spikes in vessel  1  with regulated frequency. Valve  22  is controlled by solenoid  23  as shown in  FIG. 2 . If the desired result can be achieved using of lower pressure amplitudes, this system will provides a simple and cost effective solution. 
         [0036]    With reference to  FIG. 4 , there is generally shown a cross section of another system incorporating present invention. This system is similar to the system in  FIG. 1 , except that pumps  25  and  26 , tanks  27  and  28 , and directional control valve  29  is added to provide the automatic loading and unloading of treated product  2 . Pump  25  loads the untreated product from tank  28  into vessel  1 , while pump  26  unloads the treated product from vessel  1  to tank  27 . Directional control valve  29  directs the flow of the product either from tank  28  to vessel  1  or from vessel  1  to tank  27 . 
         [0037]    With reference to  FIG. 5 , there is generally shown a cross section of another system incorporating present invention. In this system, however, pressure pulsations are produced by rotating cam  31 , which is in contact with rod  35 . Vessel  1  is placed on spring-loaded platform  36  to prevent rotating cam  31  from breaking. Cam  31  is driven by motor  32  through gear box  33 . The frequency of pulsations is regulated either by the speed of motor  32  or by switching gears in gearbox  33 . The amplitude of pressure pulsations in this system is regulated either by the stiffness of elastic elements  34  or by the contact area between rod  35  and substance  2 . 
         [0038]    With reference to  FIG. 6 , there is generally shown a cross section of another system incorporating present invention. This system is similar to that of  FIG. 5 . However, the rotating cam in this system is replaced by a number of rollers  38  formed on the outer diameter of wheel  37 . This is done to increase the frequency of pressure pulsations in substance  2 . The amplitude of pressure pulsations is controlled by the contact area between push rod  39  and substance  2 . To facilitate the use of push rods with different contact areas in one container, insert  40  is formed inside neck  11  and secured by clamp  41 . Inserts  40  always have the same outer diameters while the inner diameters are formed to accommodate push rods with different contact areas. By using various insert-push rod combinations, one can regulate the amplitude of pressure pulsations generated in substance  2 . 
         [0039]    With reference to  FIG. 7 , there is generally shown a cross section of another system incorporating present invention. In this system, however, high frequency pressure pulsations are produced by ultrasonic vibrator  47 . Ultrasonic vibrators are frequently used for various applications, including ultrasonic welding and the cleaning of metal parts. The frequency and amplitude of vibrations in these devices can be regulated. Ultrasonic device  46  is mounted on rigid column  44 , which is mounted on plate  49 . Vibrating horn  48  is attached to ultrasonic device  46 . The distance between vibrating horn  48  and plate  49  can be adjusted by moving the ultrasonic device  46  up or down on guide rail  45 . Once vessel  1  is placed on plate  49 , ultrasonic device  46  is brought down until horn  48  is in contact with the top of rod  39 , which is in contact with substance  2 . The initial pressurization of substance  2  is achieved through pressure regulating valve  43  and pump  25 . After the setup is completed, horn  48  starts vibrating, this, in turn, generates pressure pulsations in substance  2  with a frequency equal to the vibration frequency of horn  48 . Neck  42  facilitates the removal of trapped air from vessel  2 . 
         [0040]    With reference to  FIG. 8 , there is generally shown a cross section of another system incorporating present invention. However, this system is formed to be used for the treatment of solid products. Solid product  52  is vacuum-packed in plastic wrap  53  and then placed inside vessel  1 . Product  52  is suspended inside vessel  1  and surrounded by liquid  2 . Vessel  1  is sealed by cover  50 , which is secured to vessel  1  by clamp  51 . Ultrasonic device  46  generates pressure pulsations with a set frequency in liquid  2  which are transferred through liquid  2  to product  52 . Ultrasonic vibrator  47  is attached to upper plate  5 . Due to this setup, the size of vessel  1  is not limited by the size of column  44  and the quantity of substance treated in vessel  1  in one treatment cycle can be increased. 
         [0041]    With reference to  FIG. 9 , there is generally shown a cross section of another system incorporating present invention. In this system, cooling jacket  54  is formed around vessel  1  to control the temperature of substance  2  during the pulsating pressure treatment. A cooling liquid is then pumped from tank  56  by pump  55  through heat exchanger  57  into cooling jacket  54  and back into tank  56 . 
         [0042]    With reference to  FIG. 10 , there is generally shown a cross section of another system incorporating present invention. This system is similar to the system described in  FIG. 9 ; however, its cooling arrangement is made to be more efficient. In this system, rather then the cooling jacket controlling the temperature of substance  2 , substance  2  itself, is circulated by pump  58  through heat exchanger  57  during or between pressure pulsation treatments. 
         [0043]    With reference to  FIG. 11 , there is generally shown a cross section of another system incorporating present invention. In this system, however, cylinder  7  alternates between producing instantaneous pressure pulsations in substance  2 , while the substance is locked between valves  29  and  61 , and pumping parts of the substance  2  from container  1  into container  59  through nozzle  60  when valve  61  is open. Initially, control valve  22  works with a set frequency in an oscillating mode that produces pressure pulsations needed to treat substance  2 . Thereafter, treatment valve  22  shifts to the right, permitting the free flow of oil under pressure to the piston side of cylinder  7 . Valve  61 , subsequently, opens after that, permitting the substance to escape from vessel  1  into vessel  2 . Valve  24 , through which pressure was delivered to valve  22 , stays in its rightward position. System pressure, through valves  22  and  24 , acts on the piston side of cylinder  7 . Piston rod  10  extends, pushing a portion of substance  2  from vessel  1 , through valve  61  and nozzle  60 , into vessel  59 . After piston rod  10  extends fully, valve  61  shifts to block the flow from vessel  1  into vessel  59 , and valve  22  shifts to the left, connecting the piston side of cylinder  7  to tank  18 . At this moment, valve  29  shifts to the right and the untreated substance moves from storage tank  28  to vessel  1  by pump  25 . Under pressure from substance  2 , cylinder rod  10  retracts. After cylinder rod  10  retracts fully, valve  29  closes and valve  22  starts oscillating again. In this system, the automatic unloading of vessel  1  is done without additional pumps, and valves and the system can be adapted to combine different types of substance treatments in one smooth process. Each time the treated portion of substance  2  is pushed out from the bottom of vessel  1 , an untreated substance is added at the top of vessel  1 , with minimal mixing between them. By the time the added substance reaches the bottom of vessel  1  it will have been subjected to a number of high pressure pulsation treatments. Nozzle  60  will provide additional treatment to substance  2  if necessary, and other types of treatments, such as “cold vapor” and vacuum, can also be incorporated inside vessel  2 . 
         [0044]    With reference to  FIG. 12 , there is generally shown a cross sectional view of another system incorporating present invention. In this system, however, a single device generating pressure pulsations is used to consecutively treat multiple containers moving on a conveyor belt. Containers  66  are filled with the substance and placed on a conveyer  68 . Cover  65  with small opening  64  is used to minimize spillage and contamination of the substance. The conveyer moves intermittently and places each container  66  under device  69  for a set period of time. Device  69  is comprised of sealing element  70 , which contains a number of openings, and cylinder  71 . Cylinder  71  is formed to move sealing element  70  up and down from containers cover  65 . Device  69  is formed to bring pressure pulsations from pressure pulsation generator  72  to the substance in containers  66 . Any pressure pulsation generating device that has been described in the present invention can be employed in this application. The system operates in the following sequence: after container  66  is placed under sealing element  70 , cylinder  71  extends and brings sealing element  70  in contact with cover  65  to seal opening  64 ; valves  67  and  65  shift to the “open” position and pump  25  starts pumping the product from tank  28  to pressurize the substance in container  66  before the pressure pulsation treatment begins; valve  67  shifts to a closed position and pressure pulsation generator  72  starts generating pressure pulsations to treat the substance in vessel  66 ; after the treatment, valve  65  closes and valve  67  opens, allowing double rotating pump  25  to suck back the excess product and prevent spillage; valve  67  closes again, sealing element  70  is lifted and vessel  66  is moved out of the way; the next in line vessel  66  is placed under device  69 . 
         [0045]    With reference to  FIG. 13 , there is generally shown a cross sectional view of another system incorporating present invention. In this system, however, an air-hydraulic buster is incorporated to produce high pressure pulsations in treated substances. Vessel  1 , containing product  2 , and hydraulic cylinder  77  are shown in a horizontal position. Blocks  71  and  72  are mounted in pockets made in mounting plate  74  to support cylinder  77  and vessel  1  during operation. Plugs  78  and  79  are needed to close the openings in vessel  1  through which substance  2  can be loaded and unloaded. Air valve  22  brings air pressure to piston  76 , which is placed inside air-hydraulic booster  75 . Air valve  22  is controlled by an on-of pulsating signal. Through the action of piston rod  81  on the oil locked in cavity  80 , low air pressure pulsations are transformed to high pressure hydraulic pulsations acting on cylinder  77 . Since insignificant travel of piston rod  82  is required to generate pressure pulsations in substance  2 , which is locked under pressure in vessel  1 , a small air-hydraulic booster is sufficient to do the job. Air pressure is readily available in a laboratory or in industrial environment so this approach can provide a low cost and practical solution to generating high pressure pulsations with regulated frequency. 
         [0046]    With reference to  FIG. 14  and  FIG. 14A , there is generally shown a cross sectional view of another system incorporating present invention. In this system, however, two processes are involved in the treatment of liquid substances; homogenization and pressure pulsation with a set frequency are combined in the same vessel. Homogenization is a process used in the production of many foodstuffs. High pressure pulsations is this system are delivered by plunger  35 . Delivering pressure pulsations to substance  2  in container  1  can be accomplished through plunger  35  by any of the devices described above. In the arrangement shown in  FIG. 14 , pressure pulsations are delivered by ultrasonic device  44  and vibrating horn  48 . Homogenization of substance  2  is performed by cylinder  77 . Piston rod  82  of cylinder  77  is attached to rod  91  through bushing  90 . Rod  91 , through an opening in closure  83  of vessel  1 , is connected to piston  84 , which is formed with small openings  85 . Pump  25  fills vessel  1  with untreated substance from tank  28  through valve  92 . Once vessel  1  is filled, valve  92  closes. At this point in the cycle, rod  82  is fully retracted. Piston  84  is pushed against sealing ring  86 , which is retained in a groove of sliding ring  87 , thus preventing the substance from escaping through openings  85 . The process of killing bacteria in substance  2  begins when ultrasonic device  44  starts generating pressure pulsations in vessel  1 . After the ultrasonic treatment is done, the homogenizing process begins. Piston rod  82  of cylinder  77  expands, pushing piston  84  through substance  2 . Under the pressure in front of piston  84 , retainer ring  87  is pushed back against the step formed on rod  91 , thus allowing substance  2  to escape to the back of piston  84  through openings  85 . When piston  84  reaches its far right position, valve  94  opens and rod  82  of cylinder  77  begins to retract. Retaining ring  87  with sealing ring  86  is being then pushed by inertia and pressure, against the back surface of piston  84 , thus preventing substance  2  from escaping to the front of piston  84  through openings  85 . Thereafter substance  2  moves to tank  27  through valve  94 . The described system does not only allow the combination of pulsating pressure treatment and homogenization of the substance in one process, but also allows automatic unloading of the treated substance after treatment, which is another useful feature in mass production. 
         [0047]    With reference to  FIG. 15 , there is generally shown a cross sectional view of another system incorporating present invention. In this system, however, high pressure pulsation and homogenization processes are combined and accomplished by one cylinder. Cylinder  77  is controlled by valves  22  and  24 . This system works in the following sequence: as vessel  1  is filled with the untreated substance from storage tank  28  through valve  92  by pump  25 , piston  84  is pushed to its extreme leftward position. When vessel  1  is filled with substance  2 , under a pressure that is set by control valve  28 , valves  92  and  95  close; valve  22  receives an “on” or “off” signal at a set frequency, generating pressure pulsations in cylinder  77 , which are transferred to substance  2  in vessel  1 . With each pressure pulsation, piston  84  moves a small distance to the right, forcing a small portion of substance  2  through openings  85  to the rear of piston  84 , into the space that is formed by the rightward movement of piston  84 . With this approach, the homogenization process is combined with the process of destruction of bacteria by high pressure pulsations. Valve  94  is utilized at the initial stage of the treatment process in order to equalize the duration of treatment of the substance located immediately in front of piston  84 , with that of the substance located further away from piston  84 , which spends more time in vessel  1  prior to efflux from the vessel. After piston  84  travels a set distance forward, valve  94  is shifted to its leftward position, piston rod  82  retracts, and the substance is returned from the space behind piston  84  to that in front of piston  84 , where it undergoes additional pressure pulsation treatment. As soon as the initial equalization cycle is complete, valve  94  moves permanently to its rightward position, connecting the space behind piston  84  to valve  95 , which is in its closed position. At this point, piston  84  starts to move rightward again, delivering pressure pulsations to substance  2 . After it traverses some set distance (for example, one third of its total stroke), valve  95  opens, piston  84  is moved back to its starting position, and treated substance that had accumulated in the space behind piston  84  (as described above) is pushed into finished product tank  27 . Meanwhile, untreated substance is added to vessel  1  from tank  28  through open valve  92  by pump  25 , and the process resumes. 
         [0048]    In the present invention, several different methods of generating the pulsating pressure for the purpose of immobilizing the undesired microorganisms in the liquid substances are described. These systems can also be fitted with interchangeable components, including different size actuators, cylinders and inserts, to provide a variety of pressure and frequency combinations. The variety of pressure and frequency combination is needed in conducting the research into the combination of the parameters that are most effective for use in production, that achieve the best results in the most economical and efficient way. 
         [0049]    Various possible embodiments, forms and modifications of the invention, coming with the proper scope and spirit of the appended claims, will, of course, readily suggest themselves to those skilled in the art. Thus, while what has been described is at present considered to be preferred embodiments of the invention, it will be apparent to those skilled in the art that various changes and modifications can be made therein, without departing from the invention, and it is therefore the aim in the appended claims to cover all such changes and modifications as fall within the true spirit of the invention, and it is understood that, although the preferred form of the invention has been shown, various modifications can be made in the details thereof, without departing from the spirit as comprehended by the following claims.

Technology Classification (CPC): 2