Abstract:
A pressure regulated flow valve which compensates for the decreasing internal pressure inside a pressurized product dispensing container using substantially insoluble compressed gas. Where the internal pressure within the pressurized product dispensing container decreases below a certain threshold pressure, the pressure regulated valve provides for an increase in the flow of the product being dispensed from the pressurized container via the pressure regulated flow valve.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/289,505 filed Dec. 23, 2009 and entitled Pressure Regulated Flow Valve with Gas-Piston (Attorney Docket No. SUMPAC P36AUSPR), which is hereby incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a pressure regulated flow valve including a gas piston which compensates for the decreasing internal pressure inside a pressurized product dispensing container to ensure sufficient product is ejected through the valve even as the pressure in the dispensing container falls. Where the internal pressure within the pressurized product dispensing container decreases below a certain threshold pressure, the valve via the gas piston provides for an increase in the flow of the product being dispensed from the pressurized container through the pressure regulated flow valve so as to maintain a relatively consistent flow rate of product. 
       BACKGROUND OF THE INVENTION 
       [0003]    In the aerosol container industry fluorocarbons or hydrocarbons are typically utilized as the propellant in a pressurized aerosol container because these compounds are generally soluble with the product to be dispensed. These compounds remain in such a soluble state whatever amount of the product is expelled from the can thereby maintaining essentially a constant pressure within the container. In this way a constant pressure is generally available to dispense the product when the valve is actuated by a user, no matter how depleted the product in the container has become. However, due to the potential environmental harm which can be caused by the fluorocarbons and hydrocarbons to the environment, there has been increasing pressure in the market to replace the fluorocarbons and hydrocarbons with more benign propellants. 
         [0004]    Various attempts have been made to utilize compressed gases as the propellant for dispensing the product contents of a pressurized container instead of fluorocarbons, compressed air, CO2 or N2 for example. However, one major drawback associated with utilizing a compressed gas is that these gases are generally not soluble in the product. Thus, as the product contents are gradually dispensed from the pressurized container over time, the internal pressure within the pressurized container also gradually decreases. The reduction in the internal pressure of the pressurized container significantly reduces the flow rate of the remaining product contents from the pressurized container. The pressure may even drop so low as to not be able to expel any further product from the container. 
         [0005]    For example, with such compressed gases where a container is pressurized with an initial pressure of 100 psi of pressurized gas, such as air, the product will dispense initially at the intended flow rate from the pressurized container. However, as the product contents are gradually dispensed over time, the volume in the container for the compressed gas expands and the internal pressure of the container for forcing out the product gradually decreases to, for example, only 20 psi. As a result of this reduction in dispensing pressure, the flow rate of the remaining product also decreases and the product then has a tendency to trickle out of the valve as such product is dispensed. The significant pressure drop and decrease in product flow rate is generally unacceptable and has hindered the use of compressed gases in conventional valves and pressurized containers. 
       SUMMARY OF THE INVENTION 
       [0006]    Wherefore, it is an object of the present invention to overcome the above mentioned shortcomings and drawbacks associated with the prior art dispensing valves. 
         [0007]    An object of the present invention is to provide a valve which has a primary flow path through the valve and has an internal movable member which is regulated by the internal pressure of the pressurized container as well as the internal pressure of a gas piston so that as the internal pressure of the pressurized container falls below a threshold value, the gas piston biases the movable member in a manner which controls the expansion of the product flow path so that a desired sustained volumetric flow rate of product can continue to be emitted from the pressurized container despite the loss of internal pressure in the container. 
         [0008]    A further object of the present invention is to change the flow path characteristics of the pressure regulated flow valve once the internal pressure inside the pressurized container falls below a predetermined threshold pressure of between about 40 to 65 psi for example, the flow path characteristics of the regulated flow valve are automatically modified so that the cross-sectional area of the flow path is modified, and an increased volume of the product is then able to be dispensed via a larger flow path area. 
         [0009]    Another object of the present invention is to utilize a relatively environmentally harmless compressed gas, such as compressed air, CO2 or N2 as a propellant for dispensing the product contents, and thus eliminate the use of fluorocarbons, hydrocarbons and other harmful compounds as the propellant for the pressurized container. 
         [0010]    A still further object of the present invention is to provide a pressure regulated flow valve in which the associated manufacturing and assembly costs are minimized while still providing a reliable pressure regulated flow valve which can maintain a relatively consistent flow rate both at a high internal pressure and at low internal pressure. 
         [0011]    Yet another object of the present invention is to provide a pressure regulated flow valve in which the overall size and profile of the piston member, the internal pressure of the pressurized container and the pressure of the gas piston all interact with one another to dictate the threshold pressure at which the regulated flow valve transitions from high pressure condition to low pressure condition. 
         [0012]    Another object of the present invention is to provide a variably sized orifice as a primary flow path between the valve housing and the movable member which can be variably sized by relative movement of the moveable member according to the relative pressure difference between the gas piston cylinder and the container. 
         [0013]    The present invention also relates to a pressure regulated flow valve for dispensing product from a pressurized container, the pressure regulated flow valve comprising a valve housing having an upper chamber accommodating a valve stem and a lower chamber accommodating a gas piston cylinder comprising a movable piston, and a flow controller connected to the movable piston, a first pressure inside of the gas piston cylinder and a second pressure inside of the container, a passageway for dispensing variable amounts of product through the valve housing; and wherein the passageway has a variable sized opening defined by the flow controller according to a relative difference between the first and the second pressures. 
         [0014]    The present invention also relates to a method of regulating a flow valve for dispensing product from a pressurized container, the method comprising the steps of defining a valve housing having an upper chamber accommodating a valve stem and a lower chamber accommodating a gas piston cylinder comprising, a movable piston, and a flow controller connected to the movable piston, providing a first pressure inside of the gas piston cylinder and a second pressure inside of the container, forming a passageway for dispensing variable amounts of product through the valve housing, and allowing the passageway to have a variable space created by the flow controller and determined by the second pressure inside of the container. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The invention will now be described, by way of example, with reference to the accompanying drawings in which: 
           [0016]      FIG. 1  is a diagrammatic cross-sectional view of a first embodiment of the regulated flow valve and gas piston, according to the present invention, shown in a high internal container pressure closed condition; 
           [0017]      FIG. 2A  is a diagrammatic cross-sectional view of a second embodiment of the regulated flow valve and gas piston, according to the present invention, shown in an initial high internal container pressure closed condition; 
           [0018]      FIG. 2B  is a diagrammatic cross-sectional view of the second embodiment of the valve of  FIG. 2  in a low internal container pressure condition; and 
           [0019]      FIG. 3A  is a diagrammatic cross-sectional view of a third embodiment of the regulated flow valve and gas piston, according to the present invention, shown in an initial high internal container pressure condition. 
           [0020]      FIG. 3B  is a diagrammatic cross-sectional view of the third embodiment of the regulated flow valve and gas piston shown in a low internal container pressure condition. 
           [0021]      FIG. 4  is a diagrammatic cross-sectional view of the fourth embodiment of the regulated flow valve and gas piston shown in a low internal container pressure condition. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    With reference to  FIG. 1 , a detailed description concerning various components, features and functionality a first embodiment of the present invention will now be described. The pressure regulated flow valve  102  generally comprises a cylindrical valve housing  104  which is crimped in a conventional manner to a mounting cup  106 , and the mounting cup  106  is accordingly crimped in a conventional manner, to the container  108  or some other conventional pressurized container. As the general structure of aerosol containers with which the below discussed valves are compatible is generally known in the art, no further detailed discussion is provided with respect to the same. 
         [0023]    Turning specifically to the valve  102 , a valve stem  103  is supported in the housing  104  and extends through an opening in the mounting cup  106  to provide the necessary mechanical trigger and product passageway  105 , for example a tilt valve stem or vertically actuated valve stem, which permits a user to eject the pressurized product from the container  108 . The valve stem  103  has a top and bottom portion between which the valve passageway  105  extends and through which the product passes from the container  108  so as to be finally ejected from the top portion of the valve stem  103 . A stem entry orifice  107  is generally formed in a radial relationship to the valve passage  105  in the sidewall of the valve stem  103 . The orifice  107  communicates between an internal passage or cavity  110  of the valve  102  and the valve passage  105  to permit product flow into the valve passage  105  upon pressing or tilting of the valve stem  103 . 
         [0024]    A gasket  109  seals the orifice closed in an unactuated position as shown in  FIG. 1 , and in an actuated position (not shown), for example when the valve stem  103  is pressed downwards, the orifice  107  is moved away from this sealing position and comes into communication with the internal cavity  110  of the valve housing so that pressurized product in an internal cavity  110  is ejected through the valve stem  103  and to the outside environment. The valve stem  103 , mounting cup  106 , the container  108  and the arrangements and functions of these elements are generally known and thus no further discussion is provided with respect to these noted elements individually. 
         [0025]    The valve housing  104  defines the internal cavity  110  which in turn defines a flow path F for the outgoing pressurized product as it travels from the interior of the container  108  through the housing  104  to the valve stem  103 . The valve housing  104  is open at opposed upper and lower ends, with the upper end supporting the gasket  109  and stem  103  at one end thereof as described above, and as described in further detail below a pressurized product inlet at the other end including a gas piston cylinder. The internal cavity  110  is substantially cylindrical in shape and generally comprises an upper chamber portion  120  and a lower chamber portion  118 . What essentially separates the upper and lower chamber portions  118  and  120  is that the lower chamber portion  118  includes the gas piston cylinder device  122  which essentially functions as a variable gateway in the valve  102  so as to ensure a consistent dispensing of product from the valve even as the internal pressure P of the container  108  drops, as will be described in detail below. 
         [0026]    As shown, the lower chamber portion  118  in this first embodiment in  FIG. 1  includes product flow path F leading from an inlet plate orifice  124  in the lower chamber portion  118  to the internal cavity  110 . The flow path F is separate from the gas piston chamber N and is generally smaller in diameter than the gas piston cylinder  126 , although it is to be appreciated that these diameters may be equal or different diameters depending on manufacturing processes and other design considerations. A piston mechanism  130  is provided to be inserted into the lower chamber portion  118  of the valve  102 . The piston mechanism  130  comprises a gas piston  132  and a control rod  134  which are respectively received within the gas piston cylinder  126  and the lower chamber portion  118 . It is this piston mechanism  130  which directly regulates what is essentially the area of the plate orifice  124  leading to the main flow path F through which the pressurized product is passing to eventually be ejected from the container  108 . 
         [0027]    In the embodiment of  FIG. 1 , the piston  132  and control rod  134  are substantially parallel aligned and supported by a base section  136  so that the piston  132  enters and is moveably and sealably engaged within the gas piston cylinder  126 . The control rod  134 , for its part, enters through the plate orifice  124  and is correspondingly slidably received within the main flow path F. The control rod  134  and the piston  132  are immovably connected and thus, due to the relative fixed connection of the piston  132  and control rod  134  by the base  136 , as the piston  132  is motivated by the relative balance between the can pressure P and the internal pressure N of the cylinder  126 , the control rod  134  is respectively moved axially in relation to the main flow path F and the plate orifice  124 . 
         [0028]    The control rod  134  is provided with a taper  138  along its axial length extending from a larger diameter attached to the base  136  to a smaller diameter end spaced therefrom and located within the flow path F. It is to be appreciated that this taper along the length of the control rod  134  could be consistent so that the change of area of the plate orifice  124  is essentially linear relative to the length of the control rod  134 . Alternatively the taper could be variable, for example concave or convex along the length of the control rod  134 , so that the change of area of the plate orifice  124  relative to the control rod  134  was non-linear 
         [0029]    The plate orifice  124  is provided with a certain diameter in relation to the control rod  134 . In general, the plate orifice  124  is provided with a slightly larger diameter than the largest diameter of the control rod  134  so that there is always a minimal area or space between the outer diameter of the control rod  134  and the inner surface of the flow path F. Pressurized product is thus permitted to flow through this area or space defined by the plate orifice  124  and the immediately adjacent axial section of the control rod  134 . It is to be appreciated that the taper of the control rod  134  as discussed above, determines the flow path cross-sectional area depending on where the tapered control rod  134  is axially aligned with respect to the plate orifice  124  and in effect creates a variable size opening into the flow path F. It is to be appreciated that the taper on the control rod  134  may be a linear taper, or in the alternative it may also be a convex or concave taper as shown by way of example in  FIGS. 2A and 2B , or any other geometrical taper may be used which is determined to create a substantially constant product volume flow in conjunction with the pressure transition occurring in the container  108 . As the piston  132  is forced out of the cylinder  126  due to pressure balancing, discussed in further detail below, consequently the control rod  134  is pulled from the plate orifice  124 , the narrowing taper  138  of the control rod  134  allows more pressurized product through the plate orifice  124  and into the flow path. 
         [0030]    The piston cylinder  126  as seen in  FIG. 1  is provided with an initial charge pressure N which in conjunction with the well known pressure volume and area formula PV=nRT maintains the piston  132  in a substantially closed position, and the area of the plate orifice  124  is relatively small when the pressure P in the container is at full container pressure. The initial full can pressure Pi is of course relatively high and will force a desired volume of product through the plate orifice  124  and down the flow path F. In other words, the initial container pressure Pi maintains the base  136  and therefore the control rod  134  and piston  132  deeply inserted into the lower chamber portion of the valve body and there is a restricted area as defined by the plate orifice  124  and control rod  134  through which the product can pass. 
         [0031]    As the pressurized product is ejected from the container  108 , the initial pressure Pi in the container  108  gradually lowers to Pi−x. At a predetermined point, depending on the initial charge pressure N of the gas piston cylinder  126 , Pi−x attains a pressure permitting the gas piston pressure N to gradually move the piston  132  from the substantially closed position outwards. When the piston  132  is pushed out of the cylinder  126 , the entire base  136  moves as well causing the control rod  134  to move outward relative to the plate orifice  124 . When the control rod  134  moves, the flow path F increases gradually in size according to the taper  138  and allows for a greater volume of product to flow from the container to the internal cavity  110  and eventually out the valve passage  105 . The increase in the volume of the flow path as the pressure drops helps ensure a relatively constant flow of product is maintained from the device and compensates for the decrease in the internal pressure P. As the internal pressure P continues to decrease past the Pi−x threshold, the piston  132  is pushed farther and farther outward by the decreasing gas piston pressure N. This will eventually result in either the piston  132  reaching a maximum outward position and thereby defining a least restrictive position of the control rod  134 ; or it will result in the internal pressure P reaching a state of equilibrium with the gas piston pressure N. Either way, the piston  132 , and therefore the control rod  134 , alters the size of the inlet plate orifice  124  between the substantially closed position as shown in  FIG. 1  and a maximum outward position defining a least restrictive position and maximum opening for the product to flow out through the valve. 
         [0032]    In a further embodiment of the present invention shown in  FIGS. 2A-B , the flow control rod  234  is linearly attached to the movable piston  232  and axially aligned therewith. This embodiment shown in  FIG. 2  has the flow control rod  234  extending through a plate orifice  224  provided at the bottom of the housing, which is also formed axially aligned with the piston  232 , cylinder  226  and the control rod  234 . The pressure inside of the container P relative to the pressure N in the cylinder  226  is still the determining force for movement of the control rod  234  and hence the size of the flow path F. The flow path F in this embodiment is generally between the housing  204  and surrounding the cylinder  226 , and a slight space therebetween guides the product from the container in the same upward manner from the orifice  224  into the internal cavity  210  of the upper chamber  220  and eventually out the valve passage  205 . The control rod  234  tapers in the manner as described above with respect to the first embodiment. This also allows for an increase in the area of the plate orifice  224  such that when the pressure P inside of the container decreases, the piston  232  will be moved outward by the cylinder pressure N relative to the pressure P of the container  208 . As the pressure P decreases the manner in which the rod is tapered allows for smaller and smaller diameter sections of the rod  234  to pass through the orifice  224 , resulting in a larger and larger area defined by the plate orifice  224  for the product to flow through. At some point, the pressure inside of the container P will be small enough that the piston  232  will reach its most outward position relative to the cylinder  226 , which can be seen in  FIG. 2B . This will be the least restrictive position for the control rod  234  and will allow for the largest area of the orifice  224  for product to flow through. 
         [0033]    In a yet further embodiment of the present invention, the flow control device is no longer a rod or needle, but is instead a cylindrical cap  322  directly attached to the movable piston  332  as seen in  FIGS. 3A-B . The cap  322  is formed by a base  336  extending outward to a larger diameter than the piston  332  and a cylinder wall  338  depending therefrom having a larger diameter than, and extending circumferentially around the piston  332 . In this embodiment, the cylinder wall  338  has a free edge  328  which abuts with a shoulder  330  formed in the inner wall of the housing  304 . A space between the free edge  328  of the cylinder wall  338  and the shoulder  330  defines the inlet orifice  324  to the valve whereby the product to be dispensed flows into according to the container pressure P. A portion of the cylinder wall  338  contacts an inner flange  334  of the cap  322  so that a minimal space is maintained even at full can pressure between the free edge  328  of the cylinder wall  338  and the shoulder  330  to permit product to enter into the valve. 
         [0034]    This embodiment operates in a similar fashion as the previous embodiments to increase the area of the inlet orifice  324  as the container pressure P decreases. Instead of a tapered rod however, as the piston  332  moves outward due to a decrease in the pressure P inside of the container, the cylindrical cap  322  moves outward as well pulling the free edge  328  farther away from the shoulder  330  creating a larger opening and more area for the product to flow through into the valve housing and up the passage F to the upper chamber  320  and eventually out of the valve passage  305 .  FIG. 3A  shows this embodiment with the piston  332  in the initial position with high initial pressure Pi providing only a small, or the most restrictive area through the orifice  324  for the product to flow. After a certain amount of product is expelled out of the valve passage  305  through use, the pressure in the container P accordingly decreases. As previously described, the initial pressure Pi reaches a point Pi−x such that the pressure in the gas cylinder N is enough to begin to move the piston  332  outward. This outward movement moves the free edge  328  of the cap  322  away from the shoulder  330  and creates more area in the orifice  324  which thus allows more product to flow to the upper chamber  320  despite the lower pressure Pi−x in the container.  FIG. 3B  shows the present embodiment with the piston  332  and cylindrical cap  322  in the substantially entirely open position providing a larger or less restrictive path for the product to flow through the orifice  324 . 
         [0035]    In a similar embodiment of the present invention, the cylindrical wall  438  of the cap  422  directly attached to the movable piston  432  is narrowed and extends along the housing  404  as seen in  FIG. 4 . A space between the free edge  428  of the cylinder wall  438  and the housing  404  and shoulder  430  defines the inlet orifice  424  to the valve whereby the product to be dispensed flows into according to the container pressure P. The extension of the cylindrical wall  438  increases the volume of flow path F. A portion of the cylinder wall  438  contacts an inner flange  434  of the cap  422  so that a minimal space is maintained even at full can pressure between the free edge  428  of the cylinder wall  438  and the shoulder  430  to permit product to enter into the valve.  FIG. 4  shows this embodiment with the piston  432  and cylindrical cap  422  in the substantially open position providing a larger or less restrictive path for the product to flow through the orifice  424 . 
         [0036]    Since certain changes may be made in the above regulated flow valve, without departing from the spirit and scope of the invention herein involved, it is intended that all of the subject matter of the above description or shown in the accompanying drawings shall be interpreted merely as examples illustrating the inventive concept herein and shall not be construed as limiting the invention.