Patent Publication Number: US-2023158192-A1

Title: System for conveying sterilizing fluid

Description:
TECHNICAL FIELD 
     The invention relates to a system and method for conveying a sterilizing fluid to a filling machine. 
     TECHNICAL BACKGROUND 
     A processing system for producing packages filled with liquid food product typically includes a filling machine for forming the packages and filling the packages with the liquid food product. The filling machine may use a sterilizing fluid, such as hydrogen peroxide, for sterilizing both the packaging material and parts of the machine. The sterilizing fluid is circulated around the filling machine through a fluid circuit including a series of tanks, pipes, and process lines for spraying various parts of the filling machine and/or the packaging material. A conventional system for conveying the sterilizing fluid to the filling machine includes using a refilling tank containing the sterilizing fluid and a pump to convey the sterilizing fluid through the fluid circuit to a spray nozzle for the filling machine. Even though the conventional system is both functional and safe, it is desired to provide a more simple system that still assures that sterilizing fluid does not reach parts of the conveying system, or even the filling machine, that are not supposed to come into contact with sterilizing fluid. 
     SUMMARY 
     It is an object of the invention to at least partly overcome one or more limitations of the prior art. In particular, it is an object to provide a system and method that efficiently and safely conveys a sterilizing fluid to a filling machine. 
     According to an aspect of the invention, a system for conveying a sterilizing fluid to a filling machine includes a refilling tank configured for containing the sterilizing fluid and from which the sterilizing fluid is drawn, a spray tank fluidly connected to the refilling tank for receiving the sterilizing fluid from the refilling tank and conveying the sterilizing fluid to the filling machine, and a fluid line connecting the refilling tank to the spray tank. A vacuum generator is fluidly connected to the spray tank via a vacuum line and configured to generate a vacuum in the spray tank, such that the vacuum causes sterilizing fluid to be drawn from the refilling tank and into the spray tank. 
     Accordingly, in contrast to conventional systems for conveying the sterilizing fluid to the filling machine, the system described herein advantageously uses a vacuum generator, instead of a pump. The vacuum generator may have a venturi nozzle to generate a vacuum in the spray tank. The system may be switchable between a filling mode and a spraying mode. When the system is in the filling mode, the vacuum generator is in fluid communication with the spray tank to enable drawing of the sterilizing fluid into the spray tank. When the system is switched to a spraying mode, fluid communication between the vacuum generator and the spray tank is closed and the spray tank is pressurized using an air supply. The sterilized fluid may then be forced out of the spray tank to a spray nozzle for the filling machine. 
     The system may include a plurality of switchable valves that are operable in response to detected levels of the sterilizing fluid and pressure in the spray tank. Using the valves enables the system to accommodate for overpressure and prevent leakage by switching into either the filling mode or the spraying mode in response to the detected fluid levels and pressure. The system may also accommodate for failure in the fluid level sensors or pressure sensors of the spray tank by providing a safety valve that is arranged between the venturi nozzle and the spray tank. In case of failure, the safety valve is configured to stop a feeding of air through the venturi nozzle if the sterilizing fluid enters the vacuum line connected between the vacuum generator and the spray tank. 
     According to another aspect of the invention, a filling machine is arranged to fill a liquid food product into packages. The filling machine comprises the system for conveying a sterilizing fluid to a filling machine and shares the same advantages. 
     According to another aspect of the invention, a method for handling a sterilizing fluid to be used for a filling machine includes drawing the sterilizing fluid from a refilling tank, receiving the sterilizing fluid in a spray tank fluidly connected to the refilling tank, and conveying the sterilizing fluid to the filling machine. The drawing step includes generating a vacuum in the spray tank via a vacuum generator fluidly connected to the spray tank. 
     This method may include the same features as the system for conveying a sterilizing fluid to a filling machine and shares the same advantages. 
     Still other objectives, features, aspects and advantages of the invention will appear from the following detailed description as well as from the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features of the invention will now be described, by way of example, with reference to the accompanying schematic drawings. 
         FIG.  1    is a schematic drawing of a system for conveying a sterilizing fluid to a filling machine. 
         FIG.  2    is a schematic drawing of a vacuum generator of the system of  FIG.  1   . 
         FIG.  3    is a schematic drawing of a spray tank of the system of  FIG.  1   . 
         FIG.  4    is a schematic drawing of a drain for the system of  FIG.  1   . 
         FIG.  5    is a schematic drawing of a filling machine including the system of  FIG.  1   . 
         FIG.  6    is a flow chart of a method for conveying a sterilizing fluid to a filling machine using a system for conveying a sterilizing fluid, such as the system of  FIG.  1   . 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the invention will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments of the invention are shown. The invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. 
     Referring first to  FIGS.  1 - 4   , a system  1  for conveying a sterilizing fluid  2  to a filling machine  3  is shown. The filling machine  3  is be configured for forming packages and filling the packages with a liquid food product. The sterilizing fluid  2  may be hydrogen peroxide, or any other suitable sterilizing fluid. The system  1  includes a refilling tank  4  for containing the sterilizing fluid  2  and a spray tank  5  fluidly connected to the refilling tank via a fluid line  6 . The system  1  includes a fluid circuit formed of a plurality of fluid lines for transporting fluid through the system  1 . The fluid may be gas or the sterilizing fluid. The fluid circuit may be formed using any suitable pipes, hoses, tubes, or similar fluid transfer devices. The fluid lines in the system  1  may be connected using any suitable fluid couplers, fittings, or connectors. 
     The sterilizing fluid  2  is drawn from the refilling tank  4  through the fluid line  6  to the spray tank  5 . The system  1  may be oriented vertically such that the refilling tank  4  is arranged at a bottom of the system  1  and the spray tank  5  is arranged at a location above the refilling tank  4 . The sterilizing fluid  2  may thus be drawn upwardly. The spray tank  5  is configured for conveying the sterilizing fluid  2  to the filling machine  3 . The sterilizing fluid  2  may be conveyed to a spray nozzle of the filling machine  3  that is arranged to spray various parts of the filling machine  3 . Nozzles of the filling machine  3  may also be arranged to spray packaging material that is handled by the filling machine  3 . The sterilizing fluid  2  is drawn into the spray tank  5  using a vacuum generator  7  that is fluidly connected to the spray tank  5  via a vacuum line  8 . The vacuum generator  7  is configured to generate a vacuum in the spray tank  5 , such that the vacuum causes the sterilizing fluid  2  to be drawn from the refilling tank  4  as described in further detail below. Herein, “vacuum” refers to a pressure that is below the atmospheric pressure in which the system  1  typically operates, capable of drawing liquid from one tank to another. 
     The system  1  is operable in a filling mode and a spraying mode that is separate from the filling mode. When the system  1  is in the filling mode, the vacuum generator  7  is in fluid communication with the spray tank  5  for generating the vacuum and drawing the sterilizing fluid  2  into the spray tank  5  to fill the spray tank  5 . Fluid communication between the filling machine  3  and the spray tank  5  is closed during the filling mode. When the system  1  is switched to the spraying mode, the fluid communication between the vacuum generator  7  and the spray tank  5  is closed and the spray tank  5  is pressurized. The pressure in the spray tank  5  forces the sterilizing fluid  2  that was drawn into the spray tank  5  during the filling mode to be discharged from the spray tank  5  and conveyed to the spray nozzle for the filling machine  3 . Switching the system  1  between the filling mode and the spraying mode may be performed manually, such as by a system operator, or the system  1  may be automated based on the need of sterilization, detected fluid levels and pressure in the system  1 . 
     As shown in  FIG.  1   , and in detail in  FIG.  2   , the vacuum generator  7  includes a venturi nozzle  9  that is configured to generate a suction or vacuum effect when air is fed through the venturi nozzle  9 . An air supply valve  10  is fluidly connected to an air supply  11  and the venturi nozzle  9 , as shown in  FIG.  1   . The air supply valve  10  may be a three-way valve. The air supply  11  is arranged to supply air to the venturi nozzle  9  through the air supply valve  10  when the air supply valve  10  is open to enable fluid communication between the air supply  11  and the venturi nozzle  9 . The air supply valve  10  is also connected to a safety valve  12  of the vacuum generator  7  via a vacuum relief line  13  for relieving the vacuum by letting air enter the safety valve  12 . 
     The safety valve  12  is provided to prevent fluid from reaching the venturi nozzle  9  from the spray tank  5  e.g. in the event that fluid level sensors or pressure sensors in the spray tank  5  undergo a failure and the spray tank becomes over-filled, such that the vacuum causes sterilizing fluid to be drawn into the vacuum line  8 . The safety valve  12  includes a chamber  12   a  that is arranged along the vacuum line  8 , and a floater  14  located inside the chamber  12   a . The floater  14  is configured to rise and close the vacuum line  8  if the sterilizing fluid  2  flows through the vacuum line  8  and enters the chamber  12   a . A lever  15  is arranged in the chamber  12   a  and is movable by the floater  14  for closing a vacuum side port  16  of the safety valve  12  in case sterilizing fluid enters the chamber and causes the floater to rise. When the vacuum side port  16  is closed no vacuum is supplied to the vacuum line  8 . This prevents sterilizing fluid from reaching the venturi nozzle  9 , which has its vacuum port connected to the vacuum side port  16  of the safety valve  12 . A vacuum relief side port  17  of the safety valve  12  is fluidly connected to the air supply valve  10  via the vacuum relief line  13 . The air supply valve  10  can be switched to let in air that reaches the vacuum side port  16 . In this way resetting of the safety valve  12  is enabled and any sterilizing fluid can be purged from the safety valve  12  and the vacuum line  8 , allowing the fluid to flow back towards the spray tank  5 . 
     When the system  1  is in the filling mode, the vacuum side port  16  of the safety valve  12  is open and fluidly connected to the venturi nozzle  9  via a venturi line  18 . When air is fed to the venturi nozzle  9  from the air supply  11 , the vacuum is generated in the venturi line  18  and further down in the safety valve  12 , the vacuum line  8  and the spray tank  5 . An air outlet  19  of the venturi nozzle  9  is connected to an air outlet line  20  which is connected between the venturi nozzle  9  and a drain  21  for the system  1 . Air that flows through the venturi nozzle  9  to generate the vacuum leaves the system  1  via the drain  21 . 
     When the system  1  is in the filling mode, the air supply valve  10  is in a first position  10   a , in which fluid communication between the air supply  11  and the venturi nozzle  9  is open. The air supply valve  10  may be normally biased in a second position  10   b  and energized by a solenoid  22  to move to the first position  10   a . When in the first position  10   a , air from the air supply  11  is able to flow to the venturi nozzle  9 . The vacuum relief line  13  is closed by the air supply valve  10  when in the first position  10   a . The vacuum effect is generated in the venturi nozzle  9  and is effectively generated upstream through the venturi line  18 , the open vacuum side port  16  of the safety valve  12 , the chamber  12   a  of the safety valve  12 , and the vacuum line  8 , to the spray tank  5 . The vacuum effect thus occurs upwardly through the system  1  toward the venturi nozzle  9 . When the air supply valve  10  is in the second position it provides communication between the vacuum relief line  13  and the venturi nozzle, and thereby also to the drain  21 . Air may then enter form the drain and eventually flow into the chamber  12   a  of the safety valve. This enables the resetting of the safety valve  12 , allowing any fluid therein to flow back towards the spray tank  5 . For this purpose the spray tank is located vertically below the safety valve  12 . Alternatively, pressurized air may be fed into the vacuum relief line  13  for pushing liquid back towards the spray tank  5 . 
     As shown in  FIG.  1   , and in detail in  FIG.  3   , a pressure control valve  23  is connected between the vacuum line  8  and the spray tank  5  for enabling and preventing fluid communication between the vacuum generator  7  and the spray tank  5 . The pressure control valve  23  may be a three-way pilot-operated switching valve. The pressure control valve  23  is a pressure control valve in the sense that it is used for controlling whether vacuum or pressurized air shall be supplied the spray tank  5 , i.e. if under-atmospheric pressure or over-atmospheric pressure is provided for the spray tank  5 . The pressure control valve  23  may be operable by a solenoid  24 . When the system  1  is in the filling mode, the pressure control valve  23  is in a first position  23   a  in which the pressure control valve  23  is open between the vacuum line  8  and the spray tank  5  to enable generation of the vacuum in the spray tank  5 . When the system  1  is switched to the spraying mode, the pressure control valve  23  is energized to move from the first position  23   a  to a second position  23   b  in which the pressure control valve  23  closes the vacuum line  8  and thus the vacuum generator  7  relative to the spray tank  5 . When in the second position  23   b , the pressure control valve  23  enables a supply of pressurized air  11 ′ to be in fluid communication with the spray tank  5 , such that the spray tank  5  becomes pressurized. 
     The air supply is conveyed to the spray tank  5  from an air supply  11 ′ through an air supply valve  25 . The air supply valve  25  may be a solenoid valve operable by a solenoid  26 . The air supply valve  25  is normally biased in a first position  25   a  where the valve  25  is closed, and movable to a second and open position  25   b  when the solenoid  26  is energized. During the filling mode of the system  1 , the air supply valve  25  is in the closed position  25   a , such that the air supply valve  25  is in the closed position  25   a  while the pressure control valve  23  is in the first position  23   a  to enable fluid communication between the vacuum generator  7  and the spray tank  5 . When the system  1  is switched to the spraying mode, the pressure control valve  23  is energized to move to the second position  23   b  and the air supply valve  25  is moved to the open position  25   b  to open the fluid communication between the supply of pressurized air  11 ′ and the spray tank  5 . Then the pressure control valve  23  is in the second position  23   b , enabling the supply of pressurized air  11 ′ to pressurize the spray tank  5 . A filter  27  may be arranged between the air supply valve  25  and the pressure control valve  23  to ensure that only clean air enters the spray tank  5 . 
     An air-conveying valve  28  is connected between the spray tank  5  and the filling machine  3  for conveying pressurized air to the filling machine  3  during the spraying mode of the system  1 . The air-conveying valve  28  may be a pilot-operated switching valve. The air-conveying valve  28  is operable by a solenoid  29  and normally biased in a closed position  28   a  in which fluid communication between the spray tank  5  and the filling machine  3  is closed by the air-conveying valve  28 . The air-conveying valve  28  is in the closed position  28   a  when the system  1  is in the filling mode. When the system  1  is switched to the spraying mode, the air-conveying valve  28  is energized to move to an open position  28   b  in which fluid communication between the spray tank  5  and the filling machine  3  is open such that pressurized air in the spray tank  5  flows out of the spray tank  5  and toward the spraying nozzle of the filling machine  3 . The pressurized air is mixed with sterilizing fluid at the spray nozzle to generate the spray of sterilizing fluid for spraying. 
     A sterilizing fluid control valve  30  is arranged along the fluid line  6  which extends from the refilling tank  4  to the spray tank  5 . The sterilizing fluid control valve  30  is configured for conveying the sterilizing fluid  2  from the spray tank  5  to the filling machine  3 . The sterilizing fluid control valve  30  may be a three-way pilot operated switching valve and is supported by a housing  5   a  that houses the spray tank  5 . The sterilizing fluid control valve  30  may be operated by a solenoid  31  and normally biased in a first position  30   a . When the system  1  is in the filling mode, the sterilizing fluid control valve  30  is in the first position  30   a  in which the sterilizing fluid control valve  30  enables fluid communication between the fluid line  6  and the spray tank  5  to be open such that the sterilizing fluid  2  may be drawn into the spray tank  5  from the refilling tank  4 . A filter  32  may also be arranged along the fluid line  6  to ensure that only clean sterilizing fluid enters the spray tank  5 . 
     When the system  1  is switched to the spraying mode, the sterilizing fluid control valve  30  is energized to move to a second position  30   b  in which fluid communication between the refilling tank  4  and the spray tank  5  is closed and fluid communication between the spray tank  5  and the filling machine  3  is opened by the sterilizing fluid control valve  30 . When the spray tank  5  is pressurized, the sterilizing fluid  2  that was drawn into the spray tank  5  during the filling mode is pushed out of the spray tank  5  through the sterilizing fluid control valve  30 . The sterilizing fluid  2  is conveyed to the spray nozzle for the filling machine  3  for mixing with the pressurized air that is supplied via the air-conveying valve  28 . Thus, when the sterilizing fluid control valve  30  is in the second position  30   b , the air-conveying valve  28  is in the open position  28   b  such that the air and sterilizing fluid are simultaneously conveyed to the spray nozzle. The sterilizing fluid level in the spray tank  5  is regulated such that the outlet to the air-conveying valve  28  from the spray tank  5  remains above the fluid level. The outlet to the sterilizing fluid control valve  30  is located at the bottom of the spray tank  5 . 
     Switching the system  1  between the filling mode and the spraying mode may be performed in response to the fluid level in the spray tank  5 . Separate fluid level sensors or relays  33 ,  34  may be mounted in the spray tank  5  for detecting a high level and low level of the sterilizing fluid  2  in the spray tank  5 , respectively. A pressure transducer  35  is also attached to the spray tank  5  for monitoring the pressure in the spray tank  5 . More than one pressure transducer may be provided and the pressure transducers may be arranged at any suitable location along the spray tank  5 . The air supply valve  25  may be controlled in response to the pressure detected by the pressure transducer  35 . The air supply valve  25  may be energized to move to the open position  25   b  if low pressure is detected or to the closed position  25   a  if high pressure is detected. The pressure transducer  35  may also be used to prevent leakages by detecting varying amounts of pressure that occur due to insufficient tightening of fluid connectors or fittings in the fluid circuit. 
     The relays  33 ,  34  include a high level relay  33  for detecting a high level of sterilizing fluid  2  and a low level relay  34  for detecting a low level of sterilizing fluid  2 . When a low level of the sterilizing fluid  2  is detected, or a level of the sterilizing fluid  2  that is below a predetermined threshold is detected, the system  1  may be switched to the filling mode such that the vacuum generator  7  is operated and connected for fluid communication with the spray tank  5 . The air supply valve  25  is thus moved to the closed position  25   a , the air-conveying valve  28  is moved to the first position  28   a , the pressure control valve  23  is moved to the first position  23   a , and the sterilizing fluid control valve  30  is moved to the first position  30   a . The air supply valve  10  of the vacuum generator  7  is also moved to the first position  10   a . The valves may be simultaneously energized to move to the respective positions. 
     When the high level relay  33  detects that the level of the sterilizing fluid  2  in the spray tank  5  reaches a predetermined threshold, the system  1  may be switched to the spraying mode in which fluid communication between the vacuum generator  7  and the spray tank  5  is closed such that the sterilizing fluid  2  is no longer drawn into the spray tank  5 . The air supply valve  25  is moved to the open position  25   b , the pressure control valve  23  is moved to the second position  23   b , the air-conveying valve  28  is moved to the second position  28   b , and the sterilizing fluid control valve  30  is moved to the second position  30   b . The air supply valve  10  of the vacuum generator  7  is moved into the second position  10   b  for opening the vacuum relief line  13  such that the vacuum from the venturi nozzle  9  is relieved. The vacuum relief line  13  is connected to the vacuum relief side port  17  of the safety valve  12  which is open such that opening the vacuum relief line  13  enables atmospheric pressure to be generated in the vacuum line  8  when no air is being fed to the venturi nozzle  9 . 
     If the relays  33 ,  34  or the pressure transducer  30  malfunction such that the system  1  continues in the filling mode even though the spray tank  5  is full, the sterilizing fluid  2  may enter into the vacuum line  8 . If the sterilized fluid  2  reaches the chamber  12   a  of the safety valve  12  arranged along the vacuum line  8 , the floater  14  of the safety valve  12  is moved upwardly in the chamber  12   a  of the safety valve  12   a  to engage the lever  15  and close the vacuum side port  16  of the safety valve  12 . The venturi line  18  to the venturi nozzle  9  is thus also closed. This prevents further filling of sterilizing fluid into the safety valve  12 , so that no fluid reaches the venturi nozzle  9 . The system  1  may be shut off and restarted after this happens. The floater  14  may be pushed downwardly to force the sterilizing fluid  2  back through the vacuum line  8  and into the spray tank  5  by switching the air supply valve  10  to the second position  10   b . The lever  15  may be a manual valve that is manually operated by the upward and downward movement of the floater  14 . 
     As shown in  FIG.  1   , and in detail in  FIG.  4   , the sterilizing fluid  2  and air from the venturi nozzle  9  may be drained from the system  1  via the drain  21  during a draining mode. The sterilizing fluid  2  may be drained to the same outlet line  20  as the discharged air. A separate drain line that is fluidly connected to the drain  21  may also be provided. A manifold structure  36  is arranged along the fluid line  6  and includes a loading valve  37  and a drain valve  38 . The loading valve  37  may be a three-way pilot-operated valve having a solenoid  39 . The loading valve  37  may be normally biased in a first position  37   a  in which the loading valve  37  is open and enables fluid communication between the refilling tank  4  and the spray tank  5 . During the filling mode of the system  1 , the loading valve  37  is open and the drain valve  38  is in a closed position  38   a.    
     During the draining mode, the loading valve  37  is energized to move into a second position  37   b  in which the loading valve  37  is closed relative to the refilling tank  4  and sterilizing fluid  2  is no longer drawn from the refilling tank  4 . The loading valve  37  is also in the second position  37   b  during the spraying mode of the system  1 . In the drain mode, when the loading valve  37  is closed, the drain valve  38  is energized to move to an open position  38   b . The drain valve  38  may be a three-way pilot-operated valve having a solenoid  40  and is normally biased in the closed position  38   a . When the loading valve  37  is in the second position  37   b  and the drain valve  38  is in the open position  38   b , the sterilizing fluid  2  flows downwardly through the fluid line  6  and through the drain valve  38  toward the drain  21 . When this happens the air supply valve  25  and the pressure control valve  23  are in their positions to pressurize the spray tank  5  with air from air supply  11 ′. The air-conveying valve  28  and the fluid control valve  30  are then closed, such that the pressurized air can assist in draining the spray tank  5  towards the fluid line  6  and further to the drain valve  38  and the drain  21 . A fluid drain line  41  is connected between the fluid line  6  and the drain  21  and the drain valve  38  is arranged along the fluid drain line  41 . 
     The sterilizing fluid  2  may be emptied from the refilling tank  4  by repeatedly switching between the filling mode and the draining mode. The loading valve  37  and the drain valve  38  may be repeatedly opened and closed until all of the sterilizing fluid  2  is discharged to the drain  21 . The system  1  is initially in the filling mode to draw the sterilizing fluid  2  from the refilling tank  4 . When the system  1  is in the filling mode, the air supply valve  25  is in the closed position  25   a , the air-conveying valve  28  is in the first position  28   a , the sterilizing fluid control valve  30  is in the first position  30   a , and the pressure control valve  23  is in the first position  23   a . When the spray tank  5  is filled to a predetermined level as detected by the high level relay  34  and the pressure transducer  35 , the system  1  is switched into the draining mode. The filling and draining sequence may repeat until all of the sterilizing fluid  2  is removed from the system  1 . 
     The system  1  may also be configured for an operational mode in which sterilizing fluid is supplied to another unit  42  where sterilization is needed. When the system  1  is switched into the operational mode for supplying fluid to the other unit  42 , the pressure control valve  23  may be moved to the second position  23   b  in which the vacuum generator  7  is disconnected from the spray tank  5 . The vacuum generator  7  and vacuum line  8  may then be fluidly connected to the other unit  42  for generating a vacuum in the unit  42 . The sterilizing fluid control valve  30  is moved to the second position  30   b  such that the sterilizing fluid  2  is drawn into the unit  42 , rather than to the spray tank  5 . The sterilizing fluid  2  may be drawn into the unit  42  via an injection fluid line  43  that is fluidly connected to the fluid line  6 . 
     Referring now to  FIGS.  5  and  6   , the filling machine  3  may include the system  1  described herein and a sterilizing unit  44  arranged to receive the sterilizing fluid  2  from the system  1  for sterilizing parts of the filling machine  3 . A method  45  for handling a sterilizing fluid  2  to be used for a filling machine  3  is shown in a flowchart in  FIG.  6   . The method  45  may be performed using the filling machine  3  of  FIG.  5   . A step  46  of the method  45  includes drawing the sterilizing fluid  2  from a refilling tank  4 . Step  46  includes generating a vacuum in the spray tank  5  via a vacuum generator  7  fluidly connected to the spray tank  5 . A step  47  includes receiving the sterilizing fluid  2  in a spray tank  5  that is fluidly connected to the refilling tank  4 . A step  48  includes conveying the sterilizing fluid  2  to the filling machine  3 . A step  49  of the method  44  includes emptying the refilling tank  4  by repeatedly drawing the sterilizing fluid  2  into the spray tank  5  and draining the sterilizing fluid  2  out of the spray tank  5  until the refilling tank  4  is empty. 
     The system and method for conveying a sterilizing fluid to a filling machine is advantageous in that the system efficiently draws a sufficient amount of sterilizing fluid from the refilling tank to supply the fluid downstream and spray the filling machine. Another advantage of the system is that pressure sensors and separate fluid level sensors are used to detect real-time characteristics of the spray tank such that the system may accommodate for overpressure and leakage. The vacuum generator advantageously includes a safety valve for the venturi nozzle that prevents a feed of air to the venturi nozzle during a failure of the fluid level sensors or the pressure sensors for the spray tank. Still another advantage of the system is that the refilling tank may be easily emptied by a repeated process of drawing the sterilizing fluid into the spray tank and discharging the sterilizing fluid to the drain. 
     From the description above follows that, although various embodiments of the invention have been described and shown, the invention is not restricted thereto, but may also be embodied in other ways within the scope of the subject-matter defined in the following claims.