Abstract:
A system and method for the mixing and the application of liquids to various surfaces. The system includes a primary tank having a liquid fill fitting, a gas fitting, and an outlet. A pressurized gas source is in fluid communication with the primary tank by way of the gas fitting and a mixing device is in fluid communication with both the outlet and a concentrate reservoir. The mixing device is arranged and configured to mix the liquid and the concentrate into a liquid mixture. The system is configured such that the pressurized gas source expels the liquid through the outlet and the mixing device, thereby creating the liquid mixture.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims priority to copending U.S. provisional application entitled, “A DEVICE FOR THE DILUTION AND APPLICATION OF LIQUIDS,” having Ser. No. 60/314,058, filed Aug. 22, 2001, which is entirely incorporated herein by reference. 

   TECHNICAL FIELD 
   The present invention is generally related to liquid application systems and methods. More particularly, the invention relates to an application system and method wherein a concentrate is mixed with a liquid and the resulting liquid mixture is dispersed without the use of a pump. 
   BACKGROUND OF THE INVENTION 
   The use and application of liquid substances, such as cleaning preparations, pesticides, herbicides, fertilizers, coatings, lubricants etc., often require that the substances be diluted with a liquid, such as water, and the diluted preparation applied to a surface or introduced into a container. Typically, this is a multi-step operation that first involves the dilution process, which often requires that a concentrate and diluent be measured and placed into a container, and then that the combination be adequately mixed. The liquid mixture is then transferred by use of a transfer system to either be applied to a surface or introduced into a container. Typically, a pump functions as the motive force of the liquid mixture and is powered by an electric motor, by an internal combustion engine, or other appropriate means. 
   Liquid application systems are frequently encountered in the paving industry. The process of paving roads, runways, parking areas and the like with asphaltic concrete (asphalt) involves the transportation of the asphalt from the manufacturing plant to the paving site. Numerous types of vehicles are employed to transport asphalt from the manufacturing plant to the paving site. These vehicles include tandem dump trucks, tri-axle dump trucks, dump trailers, live-bottom trailers, hopper trailers, center drop trailers, double trailers, and the like. The asphalt transported by these vehicles is received “hot” so that it is in a workable condition at the paving site. To prevent the asphalt from sticking or adhering to the bed of the transportation vehicle, a lubricating type material, commonly known as an asphalt release agent, is applied to the truck bed prior to loading the asphalt. 
   The most common form of release agents are liquids which are sprayed, splashed, or otherwise applied to the vehicle truck beds. One common method of applying the release agent to the truck bed is by the use of a pump-up sprayer. In such applications, a measure of release agent is placed into the tank of the pumping unit, diluted as required (typically with water), agitated, and then pressurized to a sufficient air pressure to spray the bed of the truck. The spraying is conducted by the vehicle operator or personnel at the asphalt plant by controlling a wand or a nozzle to direct the flow of the spray unit. This method is somewhat ineffective in that the sprayers generally do not spray uniformly, and encounter decreasing air pressure while they are being used. 
   Other conventional spray units typically employ a pump to urge the diluent through the system, thereby both creating a liquid mixture including the diluent and the release agent and supplying the necessary pressure to spray the diluted release agent through an appropriate nozzle. Such units tend to suffer from a lack of control over the release agent concentration, and a lack of uniformity of application due to variability of the output pressure of the pump. 
   Accordingly, there is a need for a system and method of applying various liquid solutions wherein the concentration and application of the liquid solution can be controlled without the use of a pump. 
   SUMMARY OF THE INVENTION 
   Embodiments of the present invention provide a system and method for the mixing and the application of liquids to various surfaces. Briefly described, one embodiment of the system includes a primary tank having a liquid fill fitting, a gas fitting, and an outlet. A pressurized gas source is in fluid communication with the primary tank by way of the gas fitting and a mixing device is in fluid communication with both the outlet and a concentrate reservoir. The mixing device is arranged and configured to mix the liquid and the concentrate into a liquid mixture. The system is configured such that the pressurized gas source expels the liquid through the outlet and the mixing device, thereby creating the liquid mixture. 
   The present invention can also be viewed as providing methods for of mixing and dispensing a liquid mixture. The method includes the steps of filling a primary tank to a desired level with liquid, pressurizing the primary tank to a desired pressure with a pressurized gas source, and passing the liquid through a mixing device, thereby mixing the liquid with a concentrate to create a liquid mixture. 
   Other systems, methods, features, and advantages of the present invention will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present invention, and be protected by the accompanying claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Many aspects of the invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
       FIG. 1  is a schematic diagram of an embodiment of a liquid application system of the present invention. 
       FIG. 2  is a schematic diagram of an embodiment of a liquid application system of the present invention. 
       FIG. 3  is a schematic diagram of an embodiment of a liquid application system of the present invention. 
       FIG. 4  is a schematic diagram of an embodiment of a liquid application system of the present invention. 
   

   Reference will now be made in detail to the description of the liquid application system illustrated in the drawings. While the liquid application system will be described in connection with these drawings, there is no intent to limit it to the embodiment or embodiments disclosed therein. On the contrary, the intent is to cover all alternatives, modifications and equivalents included within the spirit and scope of the liquid application system as defined by the appended claims. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now in more detail to the drawings,  FIG. 1  illustrates an embodiment of a liquid application system  100 . Preferably, the system includes a primary tank  110 , a pressurized gas source  120 , a mixing device  130 , a concentrate reservoir  147 , and a flow activation device  150 . As shown, the primary tank includes a liquid fill fitting  112 , a gas fitting  114 , an outlet  116 , and a liquid fill control device  118 . The pressurized gas source  120  is in fluid communication with the primary tank  110  by way of the gas fitting  114 . Preferably, the gas fitting  114  is a three way valve that can be used to line-up the pressurized gas source  120  to the primary tank  110  during pressurization, isolate the primary tank  110  from the pressurized gas source  120 , and vent the primary tank  110  to atmosphere during liquid fill operations or simply to de-pressurize the primary tank  110 . The liquid fill fitting  112  is preferably a valve that is used to either line-up the primary tank  110  to a liquid source (not shown) during fill operations or isolate the primary tank  110  from the liquid source during pressurization of the tank with the pressurized gas source  120 . The liquid fill control device  118  is used to determine the amount of liquid in the primary tank  110  and thereby indicate when the flow of liquid into the tank should be secured. However, the system  100  need not include the liquid fill control device  118  as the amount of liquid to be added to the primary tank can be pre-determined before fill operations. 
   Preferably, the mixing device  130  is a venturi having an inlet side  142 , an outlet side  146 , a suction  144 , and an activation valve  145 . The inlet side  142  is adjacent the outlet  116  of the primary tank  110  and the suction  144  is in fluid communication with the concentrate reservoir  147 . The activation valve  145  is used to prevent the flow of liquid through the venturi  140  until desired. The activation valve  145  need not be a part of the venturi  140 , but instead can be on the upstream or downstream side of the venturi  140 . Preferably, a ratio selector  148  is disposed in the suction  144  between the venturi  140  and the concentrate reservoir  147 . Although not necessary to the present invention, the ratio selector  148  permits the ratio of concentrate to liquid to be adjusted, or allows the concentrate reservoir  147  to be isolated from the venturi  140 . A flow activation device  150 , a trigger activated wand  151  is shown, is frequently disposed on the outlet side of the venturi  140  to allow manual application of the liquid mixture to a desired surface. Alternatively, the venturi  140  may deliver the liquid mixture to an automatic spray device (not shown) rather than a manual one. 
   Although the system  100  can be operated manually, embodiments are envisioned wherein an electronic controller  160  is used to automatically operate the system. For example, as shown, electronic controller  160  can be used to operate some, or all, of the liquid fill fitting  112 , the gas fitting  114 , the activation valve  145 , and the ratio selector  148 . The electronic controller  160  can be used to activate/de-activate the pressurized gas source  120  as well as receive inputs from the liquid fill control device  118 . The electronic controller can be either a programmable logic controller (PLC) or a device such as a timer/relay. 
   As shown in  FIG. 2 , other embodiments include a reservoir gas tank  170  disposed between the pressurized gas source  120  and the primary tank  110 . The reservoir gas tank  170  includes an inlet and an outlet, each typically fitted with a gas fitting  114  similar to those found on the primary tank  110 . The reservoir gas tank  170  adds flexibility to the system  100  in that the primary tank  110  can be pressurized although the pressurized gas source  120  has been secured. The reservoir gas tank  170  can be lined up to multiple primary tanks  110 . 
   As shown in  FIG. 3 , other embodiments include a receiver tank  180  disposed on the downstream side of the venturi  140 . Typically, the receiver tank includes a liquid fill fitting  112 , a gas fitting  114 , and an outlet  116 , similar to those found on the primary tank  110 . The receiver tank  180  functions as a storage area for the liquid mixture after it has been prepared, but prior to application. The liquid mixture is introduced into the receiver tank  180  through the liquid fill fitting  112  while the gas fitting  114  is used to vent the receiver tank  180 . Once the liquid mixture is in the receiver tank, the liquid fill fitting  112  is used to isolate the receiver tank  180  from the primary tank  110  and the gas fitting  114  is used to pressurize the receiver tank  180  with the pressurized gas source  120 . With the receiver tank pressurized, the liquid mixture is then dispensed either through a flow activation device  150  (FIGS.  1  and  2 ), or an automatic spray device (not shown). Each primary tank  110  can be lined up with one or more receiver tanks  180 . As well, the primary tank can have one venturi  140  lined up to multiple receiver tanks  180 , or rather, have an individual venturi  140  dedicated to each receiver tank  180  as shown in FIG.  4 . This permits a single primary tank  110  to be used to prepare and store multiple liquid mixtures of varying concentrations, depending upon the settings of each venturi  140  and contents of each concentrate reservoir  147 , either independent of each other or simultaneously. Because each receiver tank is pressurized independently, the liquid mixtures contained in multiple receiver tanks may also be dispensed either simultaneously or independently. Embodiments are envisioned that include both reservoir gas tanks  170  ( FIG. 2 ) and receiver tanks  180 . 
   One embodiment does not utilize a pressurized gas source  120 , but rather, utilizes a positive displacement pump (not shown), such as a diaphragm, gear or piston type, to introduce liquid into the primary tank  110 . As liquid is pumped into the primary tank  110  with all fittings closed with the exception of the liquid fill fitting  112 , the primary tank  110  becomes pressurized as the gas present in the tank is compressed. Because no pressurized gas source  120  is required for operation, the gas fitting  114  can be omitted from this embodiment. 
   OPERATION 
   Operation of the embodiment as shown in  FIG. 1  will now be addressed. While filling the primary tank  110  with the desired liquid (preferably water), the primary tank  110  is vented through the gas fitting  114  to facilitate the operation. The liquid fill control device  118  detects and controls the amount of liquid introduced into the primary tank  110 , preferably, the amount of liquid introduced into the tank is approximately 30-95% of the volume of the primary tank  110 . Alter be introduced into the primary tank  110 , thereby negating the use of the liquid fill control device  118 . Liquid may be introduced into the primary tank  110  by any suitable means, such as gravity, pumping, or pressure from a community water system. Once the primary tank  110  has been filled to the desired level, the liquid fill fitting  112  is placed in the closed position to isolate the primary tank  110  from the source of the liquid. The primary tank  110  is next pressurized by placing the gas fitting  114  into a position that secures venting of the primary tank  110  and lines the tank up with the pressurized gas source  120 . Preferably, the pressurized gas source  120 , such as a compressor, remains lined up to the primary tank  110  during operation of the system  100 , however, the gas fitting  114  may be used to isolate the primary tank  110  after the tank has been pressurized. 
   After the primary tank  110  has been pressurized, the liquid contained therein is passed through a mixing device  130  that mixes the liquid with a concentrate stored in the concentrate reservoir  147 . As shown, the venturi  140  is the preferred mixing device. The venturi  140  may be either a fixed concentration venturi or a variable concentration venturi. To initiate flow through the venturi  140 , the activation valve  145 , such as an air actuated ball valve or a solenoid valve, is opened, thereby allowing liquid to flow into the inlet side  142  of the venturi  140 . As the liquid flows from the inlet side  142  to the outlet side  146  of the venturi  140 , concentrate from the concentrate reservoir  147  is drawn through the suction  144  and entrained in the flow of liquid. The ratio selector  148  is used to adjust the amount of concentrate entrained for a given flow rate, and therefore to adjust the concentration of the resulting liquid mixture. As shown, the flow of liquid through the venturi  140  is controlled by a trigger activated wand for manually applying the liquid mixture to a desired surface. Alternately, the liquid mixture can be directed to an automatic spray device (not shown) or a receiver tank  180  (FIG.  3 ). 
   As previously noted, an electronic controller  160  can be used to operate the system  100 . When such a device is used, the operation of the pressurized gas source  120 , gas fittings  114 , liquid fill fittings  112 , liquid fill control device  118 , and activation valve  145  are all synchronized so that the system functions in an automatic fashion. Although all embodiments of the present system  100  can be operated in an automatic fashion, the system of  FIG. 1  is discussed herein. Upon an operator activating the system  100 , the controller places the gas fitting  114  in position to vent the primary tank  110  to atmosphere and the liquid fill fitting  112  in position to fill the primary tank  110 . Sensing and control lines  162  of the controller are represented by dashed lines. Once the liquid fill control device  118  detects the desired volume of liquid in the primary tank  110 , the controller  160  isolates the primary tank  110  from the liquid supply source by repositioning the liquid fill fitting  112  and subsequently re-positions the gas fitting  114  such that the pressurized gas source  120  pressurizes the primary tank  110  to the desired pressure, preferably from approximately 50 pounds per square inch (psi) to 2000 psi. 
   Once the primary tank  110  has been pressurized, the controller  160  operates the activation valve  145 , thereby allowing liquid to flow into the venturi  140 . Flow is initiated through the venturi  140  by activating the flow activation device  150 . As shown, this is accomplished by manually pulling a trigger  152  on a wand applicator  151 . In other embodiments, flow through the venturi will initiate when the controller  160  opens the activation valve  145 , such as when the venturi is lined up to a receiver tank  170  ( FIG. 3 ) or an automatic nozzle system (not shown). Once a pre-determined volume of liquid has passed through the venturi  140 , the controller  160  will close the activation valve  145 , vent the primary tank  110  to atmosphere, and line up the liquid fill fitting  112  to fill the primary tank in preparation for the next application operation. 
   It should be emphasized that the above-described embodiments of the present liquid application system  100 , particularly, any “preferred” embodiments, are merely possible examples of implementations, merely set forth for a clear understanding of the principles of the liquid application system  100 . Many variations and modifications may be made to the above-described embodiment(s) of the liquid application system  100  without departing substantially from the spirit and principles of the liquid application system  100 . All such modifications and variations are intended to be included herein within the scope of this disclosure and the present liquid application system  100  and protected by the following claims.