Patent Publication Number: US-2017361342-A1

Title: Method and system of applying adhesive

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of the U.S. Provisional Application having the Ser. No. of 62/352,851, filed Jun. 21, 2016. 
    
    
     BACKGROUND 
     The use of liquid adhesive (i.e. an adhesive that is liquid at room temperature) is known. Such adhesives often have a carrier that can be volatilized (e.g. water, solvent, or mixtures thereof). Heat can be used to assist in this process. 
     When water is the carrier, the adhesive is referred to as a water-based or waterborne adhesive. Water-based adhesives allow for the application of adhesive without the need to hold tanks of adhesive and hoses that transport the adhesive at elevated temperatures as needed for the application of hot melt adhesives. Further, water-based adhesives often offer a more cost effective solution than hot melt adhesives. 
     However, water-based adhesives often suffer from slow set times (the time it takes an adhesive to convert into a fixed or hardened state) due to the fact that the water in the adhesive must evaporate before the adhesive is set. Conversely, hot melt adhesives offer the advantage of fast set times as they set immediately upon cooling. A short set time is particularly advantageous on a manufacturing line where longer set times decrease productivity and directly affect throughput of the manufacturing line. 
     Therefore, improvements to application systems of liquid adhesives are needed. 
     SUMMARY 
     The present disclosure relates generally to a system of applying adhesive. In one possible configuration, and by non-limiting example, the adhesive application system disclosed herein utilizes a heated air flow path and a heated adhesive flow path to dispense adhesive from an applicator. 
     In a first aspect of the present disclosure, a system for applying an adhesive is disclosed. The system includes an air flow path for conveying compressed air and an adhesive flow path for conveying liquid adhesive. The system includes an air heater coupled to the air flow path and configured to heat the compressed air and a liquid adhesive heater coupled to the adhesive flow path and configured to heat the liquid adhesive. The system also includes an applicator positioned downstream from the air and liquid adhesive heaters. The applicator is configured to receive the liquid adhesive from the adhesive flow path and the compressed air from the air flow path. The applicator is further configured to spray the liquid adhesive from the applicator using the compressed air. 
     In a second aspect of the present disclosure, a system for applying an adhesive is disclosed. The system includes an air flow path for conveying compressed air and an adhesive flow path for conveying liquid adhesive. The system includes an air heater coupled to the air flow path and configured to heat the compressed air and a heating air line that extends along at least a portion of the air flow path downstream of the air heater. The heating air line is configured to heat the compressed air. The system also includes an applicator positioned downstream from the air heater and heating air line. The applicator is configured to receive the liquid adhesive from the adhesive flow path and the compressed air from the air flow path. The applicator is further configured to spray the liquid adhesive from the applicator using the compressed air. 
     In a third aspect of the present disclosure, a method for applying a water-based adhesive is disclosed. The method includes receiving compressed air into an air flow path and pumping liquid adhesive from a source of liquid adhesive into an adhesive flow path. The method also includes heating the compressed air in the compressed air flow path using an air heater and heating the liquid adhesive in the adhesive flow path using a liquid adhesive heater. The method includes receiving the liquid adhesive from the adhesive flow path and the compressed air from the air flow path at an applicator and spraying the liquid adhesive from the applicator using the compressed air. 
     In a fourth aspect of the present disclosure, a method for applying a water-based adhesive is disclosed. The method includes receiving compressed air into an air flow path and pumping liquid adhesive from a source of liquid adhesive into an adhesive flow path. The method also includes heating the compressed air in the compressed air flow path using an air heater and heating the compressed air along at least a portion of the air flow path downstream of the air heater using a heating air line. The method includes receiving the liquid adhesive from the adhesive flow path and the compressed air from the air flow path at an applicator and spraying the liquid adhesive from the applicator using the compressed air. 
     A variety of additional aspects will be set forth in the description that follows. The aspects can relate to individual features and to combinations of features. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the embodiments disclosed herein are based. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following drawings are illustrative of particular embodiments of the present disclosure and therefore do not limit the scope of the present disclosure. The drawings are not to scale and are intended for use in conjunction with the explanations in the following detailed description. Embodiments of the present disclosure will hereinafter be described in conjunction with the appended drawings, wherein like numerals denote like elements. 
         FIG. 1  illustrates a schematic view of an adhesive application system, according to one embodiment of the present disclosure. 
         FIG. 2  illustrates an example of the adhesive application system of  FIG. 1 ; 
         FIG. 3  illustrates a schematic view of an air preparing system, according to one embodiment of the present disclosure. 
         FIG. 4  illustrates an example of the air preparing system of  FIG. 3 . 
         FIG. 5  illustrates an example of the air preparing system of  FIG. 3 . 
         FIG. 6  illustrates a schematic view of an adhesive preparing system, according to one embodiment of the present disclosure. 
         FIG. 7  illustrates an example of the adhesive preparing system of  FIG. 6 . 
         FIG. 8  illustrates an example of the adhesive preparing system of  FIG. 6 . 
         FIG. 9  illustrates a schematic view of a heater system, according to one embodiment of the present disclosure. 
         FIG. 10  illustrates an example of the heater system of  FIG. 9 . 
         FIG. 11  illustrates a schematic view of an applicator, according to one embodiment of the present disclosure. 
         FIG. 12  illustrates a schematic view of a nozzle, according to one embodiment of the present disclosure. 
         FIG. 13  illustrates an example of a portion the adhesive application system and the applicator of  FIG. 11 . 
         FIG. 14  illustrates an example of a portion the adhesive application system and the applicator of  FIG. 11 . 
         FIG. 15  illustrates an example of a portion the adhesive application system and the applicator of  FIG. 11 . 
         FIG. 16  illustrates an example of a portion the adhesive application system and the applicator of  FIG. 11 , including an adhesive line purge valve. 
         FIG. 17  illustrates a schematic view of a power and control system, according to one embodiment of the present disclosure. 
         FIG. 18  illustrates an example of the power and control system of  FIG. 17 . 
         FIG. 19  illustrates an example of the power and control system of  FIG. 17 , depicting internal components. 
         FIG. 20  illustrates a chart of example adhesives capable of being used with the adhesive application system of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments will be described in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. Reference to various embodiments does not limit the scope of the claims attached hereto. Additionally, any examples set forth in this specification are not intended to be limiting and merely set forth some of the many possible embodiments for the appended claims. 
     The adhesive application system disclosed herein is configured to use a heated air flow path and a heated adhesive flow path to dispense a water-based adhesive. The heated air flow path and heated adhesive flow path allow for the system to dispense a water-based adhesive that has a lower adhesive set time than other traditional water-based adhesive application systems. A lower set time improves productivity and increases efficiency. 
       FIG. 1  shows an adhesive application system  100 . The system  100  includes an air input  102 , an adhesive input  104 , and a power input  106 . The adhesive application system  100  also includes a frame  108 , an air preparing system  110 , an adhesive preparing system  112 , an applicator  116 , and a power and control system  117 . 
     The system  100  is configured to deliver a water-based adhesive  103  to a sprayable media  118 . In some embodiments, the sprayable media  118  is a chipboard, an air filter substrate, or other surface where an adhesive is needed. In some embodiments, the system  100  can be positioned on or near a conveyor  119 , or like conveying system, so that the system  100  can apply the adhesive  103  to a plurality of sprayable media  118  in a short amount of time. 
     The air input  102  is configured to receive an air flow from an air source  120  that is external to the system  100 . In some embodiments, the air source  120  is a compressor that provides compressed air to the air input  102 . In some embodiments, the air source  120  can provide compressed air to the air input  102  of between about 5 psi and 50 psi, or even between about 20 psi and 35 psi. In still other embodiments, the air source  120  can provide compressed air to the air input  102  of between about 25 psi and 30 psi. The air source  120  can be positioned in close proximity to the system  100  or, in other embodiments, the air source  120  can be an air line that connects to a compressed air system in a building (i.e., a manufacturing facility). In some embodiments, the air input  102  is configured to provide compressed air to the air preparing system  110  and the adhesive preparing system  112 . 
     The adhesive input  104  is configured to receive a flow of water-based adhesive  103  from an adhesive source  122 . In some embodiments, the adhesive source  122  is a holding tank. The type of adhesive  103  will be described in more detail with respect to  FIG. 20   
     The power input  102  is configured to receive power from a power source  124 . The power source  124  can be in the form of AC or DC power. In some embodiments, the system  100  can be attached to a 240 volt AC power source in a facility such as a manufacturing facility. 
     The frame  108  of the system  100  is configured to stabilize and support the system  100 . In some embodiments, the frame  108  includes a main frame  126  and frame arm  128 . The frame arm  128  can be either fixed or movable about the main frame  126 . The frame arm  128  is configured to support the applicator  116 . When movable about the main frame  126 , the frame arm  128  can be selectively positioned to control the direction and distance at which the system  100  applies sprayed adhesive  103 . This can be advantageous when needing to apply adhesive  103  to sprayable media  118  that has a complicated shape or unwieldy size. 
     The main frame  126  is configured to be positioned or mounted to a variety of different surfaces. For example, the main frame  126  can be mounted to a floor, beam, or other support structure in a manufacturing facility. In other embodiments, the frame is not fixed to a surface, thereby making the system  100  portable. 
     The air preparing system  110  is configured to receive an air flow from the air source  120  at the air input  102 , treat the air flow, and convey the air flow along an air flow path to the applicator  116 . The air preparing system  110  conveys the air through a heating air line  127 . The heating air line  127  includes a heated hose  130 , a manifold  131 , and a pair of air lines  132   a ,  132   b . Air travels through the heated hose  130  to the manifold  131  and through the pair of air lines  132   a ,  132   b , which connect to the applicator  116 . The heated hose  130  connects a portion of the air preparing system  110  with the manifold  131 . The air preparing system  110  will be described in more detail with respect to  FIGS. 3-5  and  FIGS. 9-10 . 
     The adhesive preparing system  112  is configured to receive the adhesive  103  from the adhesive source  122  at the adhesive input  104 , treat the adhesive  103 , and convey the adhesive  103  along an adhesive flow path to the applicator  116 . The adhesive preparing system  112  conveys adhesive  103  along an adhesive line  134  to the applicator  116 . The adhesive preparing system  112  will be described in more detail with respect to  FIGS. 6-10 . 
     The applicator  116  is operable by compressed air: however, in some embodiments the applicator  116  is operable, or triggered, mechanically. In some embodiments, the applicator  116  includes an applicator heater  113  that at least partially surrounds the applicator  116 . In particular, the applicator  116  is configured to receive air from the air preparing system  110  via a trigger line  114 , air from the air preparing system  110  via the heating air line  127 , and adhesive  103  from the adhesive preparing system  112  via the adhesive line  134 . The applicator  116  is configured to deliver a spray of adhesive  103  from a nozzle  136  using the compressed air. In some embodiments, the applicator  116  is configured to deliver an atomized spray of adhesive  103  to the sprayable media  118 . In other embodiments, the applicator  116  is configured to deliver a bead of adhesive  103  to the sprayable media  118 . The applicator  116  can be manually operated or it can be automatically operated by the power and control system  117 . The applicator  116  will be described in more detail with respect to  FIGS. 11-16 . 
     The power and control system  117  is configured to at least partially control the operation of the air preparing system  110 , the adhesive preparing system  112 , and the applicator  116 . The power and control system  117  can also be configured to distribute power received at the power input  106  from the power source  124  to different components of the system  100 . The power and control system  117  will be described in more detail with respect to  FIGS. 17-20 . 
       FIG. 2  shows an example of the adhesive application system  100 . The air preparing system  110 , adhesive preparing system  112 , and power and control system  117  are shown mounted to the main frame  126 . The applicator  116  is shown mounted to the frame arm  128 . 
       FIG. 3  shows the air preparing system  110 . The air preparing system  110  includes an air heater  129 , the heating air line  127 , a trigger line  114 , and a set of air preparing controls  138 . As shown, the heating air line  127  includes the heated hose  130 , the manifold  131 , and the pair of air lines  132   a ,  132   b . The air preparing system  110  is configured to convey air from the air source  120  along an air flow path  140  to the applicator  116 . 
     The air heater  129  is a heater that is powered by electricity and is configured to heat the compressed air received from the air input  102 , upstream from the applicator  116 . In some embodiments, the air heater  129  receives electric power from the power source  124  via the power and control system  117 . The air heater  129  includes an inlet  142  and an outlet  144 . At the inlet  142 , compressed air enters the air heater  129  and begins receiving heat generated by the air heater  129 . At the outlet  144 , compressed air exits the air heater  129  via the heated hose  130  at a temperature higher than it entered. 
     In some embodiments, the air heater  129  is an aluminum block heater, alternatively the block heater can comprise stainless steel, a ceramic or a coated metal. The compressed air that enters at the inlet  142  takes a serpentine path through a plurality of interior sealed channels (not shown) within the heater  129  until the air exits at the outlet  144 . Therefore, the air exiting the air outlet  144  is at a higher temperature than the air entering at the air inlet  142 . Air flow through the heater  129  is provided by the air source  120  (e.g., a compressor). 
     In some embodiments, the air heater  129  is configured to heat the air along the air flow path  140  to a temperature of between about 300 degrees Fahrenheit and about 450 degrees Fahrenheit, to a temperature of between about 350 degrees Fahrenheit and about 450 degrees Fahrenheit, or even to a temperature between about 375 degrees Fahrenheit and about 425 degrees Fahrenheit. In some embodiments, the air heater  129  is configured to heat the air along the air flow path  140  to about 400 degrees Fahrenheit. In some embodiments, the air heater  129  includes a temperature sensor such as a resistance temperature detector (RTD)  143  to monitor the temperature of the air heater  129 . In some embodiments, the RTD  143  is in communication with the power and control system  117  so that the power and control system  117  can automatically adjust the temperature of the air heater  129  based on the temperature measurement from the RTD  143 . In other embodiments, the air heater  129  includes a thermocouple instead of an RTD. In some embodiments, the air heater  129  is a 400 watt heater. 
     The heating air line  127  is configured to extend along at least a portion of the air flow path  140 , downstream of the air heater  129 . The heating air line  127  is further configured to apply heat to the compressed air within the air flow path  140  between the air heater  129  and the applicator  116 . Specifically, the heating air line  127  is configured to deliver a heated atomization air flow and a heated fan air flow to the applicator  116 . The heating air line  127  includes the heated hose  130 , manifold  131 , and air lines  132   a ,  132   b.    
     The heated hose  130  is flexible and extends along at least a portion of the air flow path  140  downstream of the air heater  129 . The heated hose  130  is configured to apply heat to the compressed air leaving the air outlet  144  of the air heater  129 . In some embodiments, the heated hose  130  raises the temperature of the compressed air passing therethrough. In other embodiments, the heated hose  130  is configured to maintain the temperature of the air passing therethrough at or above a present temperature value. 
     At a first end  146 , the heated hose  130  is fluidly connected to the air outlet  144  of the air heater  129  and, at an opposite second end  148 , the heated hose  130  is fluidly connected to the manifold  131 . Air flows in a sealed channel within the heated hose  130  from the first end  146  to the second end  148 . In some embodiments, the heated hose  130  surrounds the majority of the air lines  132   a ,  132   b.    
     The heated hose  130  includes a heating element  125  disposed therein. In some embodiments, the heating element  125  is a coiled wire that is configured to heat an interior channel of the heated hose  130 . The heating element  125  can travel the length of the heated hose  130  and can be circumferentially positioned around the interior channel of the heated hose  130 . In some embodiments, the heating element  125  is a 25 watts/foot heating element capable of being powered by the power and control system  117 . In some embodiments, the heated hose  130  includes a layer of thermal insulation around the heating element  125  to aid in heat retention. The amount of insulation can be varied to improve the heat retention properties of the heated hose  130 . Around the insulation, in some embodiments, the heated hose  130  includes an outer protective layer, such as a polyamide braided sheath. The outer protective surface serves to protect the interior components from abrasion and allows for safe handling of the heated hose  130 . In some embodiments, the heated hose  130  can include a strength member embedded therein, such as a stainless steel braided sheath. 
     In some embodiments, the heated hose  130  includes a temperature sensor  150  such as an RTD or thermocouple. In some embodiments, like the RTD  143  of the air heater  129 , the power and control system  117  is in communication with the temperature sensor  150  of the heated hose  130  so as to allow the power and control system  117  to control the behavior of the heated hose  130 , such as its operating temperature. 
     In some embodiments, the heated hose  130  is about six feet in overall length from the first end  146  to the second end  148 . In some embodiments, the heated hose  130  has a #6 core size having an internal channel diameter of about ⅝ inches. In other embodiments still, the heated hose  130  is configured to be operated between about 350 degrees Fahrenheit and about 450 degrees Fahrenheit, or even between about 375 degrees Fahrenheit and about 425 degrees Fahrenheit In some embodiments, the heated hose  130  is configured to heat the air along the air flow path  140  to about 400 degrees Fahrenheit. 
     A variety of combinations of heating elements and thermal insulation that form a heated/insulated passage between the air heater  129  and the applicator  116  including, but not limited to, a heated hose  130 , may be utilized and is considered within the scope of the present disclosure. 
     The manifold  131  allows air flow to be transferred from the heated hose  130  to the air lines  132   a ,  132   b  and then to the applicator  116 . The air lines  132   a ,  132   b  are configured to create a sealed fluid connection between to the manifold  131  and the applicator  116 . In some embodiments, the air lines  132   a ,  132   b  are silicon tubing. In some embodiments, the air lines  132   a ,  132   b  are disposed with the heated hose  130 , eliminating the need for a manifold. In such an embodiment, the air lines  132   a ,  132   b  are configured to create a sealed fluid connection between the outlet  144  of the air heater  129  and the applicator  116 . Also in such an embodiment, the air lines  132   a ,  132   b  are configured to be insulated and/or receive heat from the heated hose  130 . In some embodiments, the air line  132   a  supplies atomization air flow to the applicator  116  and the air line  132   b  supplies fan air flow to the applicator. This will be discussed in more detail with respect to  FIGS. 11-16 . 
     The trigger line  114  is configured to selectively convey compressed air from the air input  102  to the applicator  116  so as to cycle the applicator  116  between an on (i.e., spraying) and an off (i.e., not spraying) operation. In some embodiments, the trigger line  114  includes a valve  111  that can be either manually or automatically operated to either allow air flow along the trigger line  114  or block air flow along the trigger line  114 . In the depicted embodiment, the trigger line  114  bypasses the air heater  129  and the heated hose  132 . In some embodiments, the trigger line  114  is controlled by the air preparing controls  138  and/or the power and control system  117 . 
     The air preparing controls  138  are configured to alter the flow and pressure of air through the system  100 . Specifically, the air preparing controls  138  are configured to allow a user to alter the pressure at which the air is provided to the applicator  116  via air lines  132   a ,  132   b  and via the trigger line  114 . In some embodiments, the air preparing controls  138  are controlled by the power and control system  117 . 
     Examples of the air preparing controls  138  are shown in  FIGS. 4 and 5 . As shown in  FIG. 4 , a regulator  152  is shown to control the pressure being delivered to the applicator  116  via the trigger line  114 . A second regulator  154  is shown to control the pressure being delivered to the applicator  116  via the heating air line  127 . Each regulator  152 ,  154  includes a pressure gauge dial  156  and an adjustment knob  158 . Each regulator  152 ,  154  is configured to selectively control the air pressure being delivered to the heating air line  127  and the trigger line  114 , respectively. In other embodiments, the preparation controls  138  are digital and can be adjusted via the power and control system  117  of the adhesive application system  100 . 
       FIG. 5  shows an example of the air preparing controls  138  located near the applicator  116  at the manifold  131 . As shown, a fine adjustment knob  155  is disposed on the air line  132   a  and a similar fine adjustment knob  157  is shown on air line  132   b . The fine adjustment knobs  155 ,  157  allow the user to further fine tune the air flow and pressure that is delivered to the applicator  116  via lines air  132   a ,  132   b . Therefore, in some embodiments, the regulator  154 , shown in  FIG. 4 , can be used for gross regulation of the air flow along the heating air line  127 , while the fine adjustment knobs  155 ,  157  can be used for finer adjustments to the air flow in air lines  132   a ,  132   b.    
       FIG. 6  shows the adhesive preparing system  112 . The adhesive preparing system  112  includes a pump  160 , an adhesive heater  162 , and a set of adhesive preparation controls  164 . The adhesive preparing system  112  is configured to convey adhesive  103  from the adhesive source  122  along an adhesive flow path  166  to the applicator  116 . 
     The pump  160  is configured to create a flow of adhesive  103  from the adhesive source  122  along the adhesive flow path  166 . As shown, the pump  160  is internal to the system  100 , specifically to the adhesive preparing system  112 . However, in some embodiments, the pump  160  can be positioned exterior to the system  100 . For example, the pump  160  can be positioned with the adhesive source  122 . 
     The pump  160  includes an inlet  168  and an outlet  170 . The pump  160  draws adhesive  103  from the adhesive source  122  through the adhesive input  104  to the inlet  168  of the pump. The pump  160  then pushes the adhesive  103  out of the outlet  170  along the adhesive flow path  166  to the applicator  116 . 
     In some embodiments, the pump  160  is a piston pump powered by the air source  120  via a pump air line  172 . In some embodiments, the maximum air input pressure via pump air line  172  is about 125 psi. In other embodiments, the maximum fluid pressure of the pump  160  is about 625 psi. 
     The adhesive heater  162  receives adhesive flow from the pump  160  along the adhesive flow path  166 . The adhesive heater  162  is substantially similar to the air heater  129 , described above. The adhesive heater  162  is a heater that is powered by electricity and is configured to apply heat to the adhesive  103  from the adhesive source  122 . In some embodiments, the adhesive heater  162  receives electric power from the power and control system  117 . The adhesive heater  162  includes an inlet  174  and an outlet  176 . At the inlet  174 , adhesive  103  enters the adhesive heater  162  and begins receiving heat generated by the air heater  129  until the adhesive  103  exits at the outlet  176 . 
     In some embodiments, the adhesive heater  162  is an aluminum block heater, alternatively the adhesive heater can comprise stainless steel, a ceramic or a coated metal. The adhesive  103  that enters at the inlet  174  takes a serpentine path through a plurality of interior sealed channels within the adhesive heater  162 , and exits at the outlet  176 . The adhesive  103  exiting the adhesive heater outlet  176  is at a higher temperature than the adhesive  103  entering at the heater inlet  174 . 
     In some embodiments, the adhesive heater  162  is configured to heat the adhesive  103  along the adhesive flow path  166  to a temperature between about 75 degrees Fahrenheit and about 300 degrees Fahrenheit, between about 120 degrees Fahrenheit and about 210 degrees Fahrenheit, or even between about 140 degrees Fahrenheit and about 170 degrees Fahrenheit. In some embodiments, the adhesive heater  162  is configured to heat the adhesive  103  along the adhesive flow path  166  to about 170 degrees Fahrenheit. Similar to the air heater  129 , the adhesive heater  162  can include a temperature sensor such as an RTD  178 . In some embodiments, the RTD  178  is in communication with the power and control system  117  so that the power and control system  117  can automatically adjust the temperature of the adhesive heater  162  based on a temperature measurement taken by the RTD. In other embodiments, the adhesive heater  162  includes a thermocouple instead of an RTD. In some embodiments, the adhesive heater  162  is a 400 watt heater. 
     The adhesive preparation controls  164  are configured to alter the flow of adhesive  103  through the system  100 . Specifically, the adhesive preparation controls  164  are configured to allow a user to alter the flow rate at which the adhesive  103  is provided to the adhesive heater  162  and to the applicator  116  via the adhesive line  134 . In some embodiments, the adhesive preparation controls  164  are in communication with the power and control system  117 . 
     An example of the adhesive preparing system  112  is shown in  FIG. 7 . The adhesive preparing system  112  is shown mounted to the main frame  126  of the system  100 . 
     An example of the adhesive preparation controls  164  is shown in  FIG. 8 . As shown, a regulator  179  is shown to be connected to the pump air line  172 . The regulator  179  is configured to alter the amount of compressed air that is delivered to the pump  160 . By altering the amount of compressed air delivered to the pump  160 , the regulator  179  can alter the output of flow of the adhesive  103  from the pump (i.e., varying the displacement). The regulator  179  includes a pressure gauge dial  180  and an adjustment knob  181 . In some embodiments, like the air preparing controls  138 , the adhesive preparation controls  164  can include fine adjustment controls located near the applicator  116  along the adhesive line  134 . In other embodiments, the controls  164  are digital. 
       FIG. 9  shows an example heater system  182  that includes the air heater  129  and the adhesive heater  162 . The heaters  129 ,  162  are contained within a single housing  183 . Because both heaters  129 ,  162  operate similarly, containing both within a single housing  183  can offer advantages to the system  100  such as easing serviceability, reducing heat loss of the heaters  129 ,  162  to other parts of the adhesive application system  100 , and improving safety by shielding the heaters  129 ,  162  with the housing  183 . In some embodiments, the housing  183  can be insulated to help reduce heat loss. 
       FIG. 10  shows an example of the heater system  182 . In the example, a plurality of electrical connections  175  are shown to be contained within the housing  183 . The electrical connections  175  can deliver power and control signals to the air and adhesive heaters  129 ,  162  from the power source  124  and/or the power and control system  117 . 
       FIG. 11  shows a schematic of the applicator  116 . The applicator  116  includes the applicator heater  113 , an applicator body  184 , a plurality of inputs  177 , and the nozzle  136 . The applicator  116  is configured to deliver an atomized spray of the adhesive  103 , delivered from the adhesive line  134 , to the sprayable media  118 . 
     The applicator heater  113  is configured to apply heat to the applicator  116 , specifically the applicator body  184 . By heating the applicator body  184 , heated air entering via air lines  132   a ,  132   b  is less likely to substantially lower in temperature once entering the applicator body  184  and prior to being expelled from the nozzle  136 . The applicator heater  113  can be a block heater that at least partially surrounds the applicator body  184 . In some embodiments, the applicator heater  113  includes an electric heating element. 
     The applicator heater  113  is in communication with the power and control system  117  so that the power and control system  117  can alter the temperature of the applicator heater  113 . In some embodiments, the applicator heater  113  includes a temperature sensor  115  that is configured to measure the temperature of the applicator heater  113 . In some embodiments, the applicator heater  113  is maintained at a temperature of between room temperature and about 300 degrees Fahrenheit, between about 120 degrees Fahrenheit and about 210 degrees Fahrenheit, or even between about 140 degrees Fahrenheit and about 170 degrees Fahrenheit In other embodiments, the applicator heater  113  is maintained at a temperature of about 150 degrees Fahrenheit. 
     As mentioned above, the applicator  116  includes a plurality of inputs  177  that are configured to receive the air lines  132   a ,  132   b , the trigger line  114 , and the adhesive line  134 . The air line  132   a  delivers heated atomization air to the applicator, the air line  132   b  delivers heated fan air to applicator  116 , the trigger line  114  delivers air that is configured to cycle the applicator between on/off, and the adhesive line  134  delivers heated adhesive  103  to the applicator  116 . In some embodiments, the adhesive line  134  enters the applicator  116  on the applicator body  184  away from the applicator heater  113 . 
     An example nozzle  136  is shown in  FIG. 12 . The nozzle  136  is configured to help apply a spray of adhesive  103  to the sprayable media  118 . The nozzle  136  includes an adhesive channel  185  in which an adhesive stream  186  of adhesive  103  flows, atomization air channels  187  in which atomization air streams  188  flow, and fan air channels  189  in which fan air streams  190  flow. The fan air channels  189  are positioned within fins  191  on the nozzle  136 , away from the atomization air channels  187  and the adhesive channel  185  which are positioned in a pocket  192  of the nozzle  136 . The nozzle  136  is configured to allow the applicator  116  to apply the atomization air streams  188  (from air line  132   a ) and the fan air streams  190  (from air line  132   b ) to the adhesive stream  186  as it leaves the applicator  116 . The atomization air streams  188  and the fan air streams  190  help to atomize and shape the spray of adhesive  103 . 
     Because the atomization air streams  188  and the fan air streams  190  are heated by the heating air line  127 , and the applicator body  184  is heated by the applicator heater  113 , heated compressed air exits the nozzle  136  at a temperature that aids in vaporizing at least a portion of the water content of the adhesive  103  in the adhesive stream  186 . By vaporizing the adhesive  103  leaving the applicator  116 , the time that the adhesive  103  takes to set (e.g., set time) can be controlled. In some embodiments, the set time is lower (i.e., faster) when compared to a system using unheated atomizing and fan air. By lowering the set time, productivity can be increased and less adhesive  103  is used from the adhesive source  122 , which is cost effective. 
     In some embodiments the applicator  116  includes a zero cavity needle to selectively open and close the adhesive channel  185 . The zero cavity needle prevents adhesive build up in the adhesive channel  185  to prevent the applicator  116  from clogging. In some embodiments, the zero cavity needle is attached to a spring-loaded plunger that resides in a cavity in the applicator body  184 . The needle can be biased to a closed position and then move to an open position so as to expel adhesive  103  from the applicator  116 , thereby overcoming the spring force when the cavity receives air from the trigger line  114 . 
       FIGS. 13-16  show an example of the applicator  116  and the system  100 .  FIG. 13  shows the applicator  116  with the applicator heater  113  partially surrounding the applicator body  184 .  FIGS. 14-15  show the applicator  116  and the applicator heater  113  attached to the frame arm  128 . Also shown is the manifold  131  from which the heated hose  130  connects and the air lines  132   a ,  132   b  exit.  FIG. 16  shows a purge valve  193  disposed along the adhesive line  134 . The purge valve  193  can be selectively activated via a lever  194  so as to drain adhesive  103  from the adhesive line  134  to prevent clogging. 
       FIG. 17  shows the power and control system  117 . The power and control system  117  is connected to the power source  124  at the power input  106 , the air preparing system  110 , the applicator  116 , and the adhesive preparing system  112 . As described above, the power and control system  117  is configured to supply power to and control the operation of a plurality of the components in system  100 . 
     In the depicted embodiment, the power and control system  117  is configured to monitor and control four separate zones: zone  1 , zone  2 , zone  3 , and zone  4 . The zones represent different components in the adhesive application system  100 . The power and control system  117  is configured to receive inputs from sensors located in each zone, and alter the operating characteristics of each zone depending on the values measured by the sensors. In some embodiments, the sensors are temperature sensors such as RTD  143  of the air heater  129 , sensor  150  on the heated hose  130 , RTD  178  on the adhesive heater  162 , and the temperature sensor  115  on the applicator heater  113 . In some embodiments, power and control system  117  can control and monitor more or less zones. 
     In one example, the zones represent the heat sources in the adhesive application system  100 . For example, zone  1  represents the heated hose  130 , zone  2  represents the applicator heater  113 , zone  3  represents the adhesive heater  162 , and zone  4  represents air heater  129 . Each zone can be set at a preset temperature, and the power and control system  117  will monitor and adjust the power being sent to the various components to maintain such a preset temperature. In one embodiment, zone  1  is preset to maintain a temperature of about 400 degrees Fahrenheit, zone  2  is preset to maintain a temperature of about 150 degrees Fahrenheit, zone  3  is preset to maintain a temperature of about 150 degrees Fahrenheit, and zone  4  is preset to maintain a temperature of about 400 degrees Fahrenheit. The power and control system  117  can also monitor and power a variety of other different components of the adhesive application system  100 , such as spraying parameters. 
       FIGS. 18 and 19  show an example power and control system  117 . The power and control system  117  includes a housing  195 , a readout  196 , a standby knob  197 , and a power switch  198 . The housing  195  is configured to store related electronics  199  of the power and control system  117 . For example, the electronics  199  can include a microprocessor  201  and connection terminals  202  to connect components of the adhesive application system  100  to the power and control system  117 . 
     The readout  196  is configured to display the preset temperature value of each of the zones along with the real-time measured value for each zone. 
     The standby knob activates a standby setting where the power and control system  117  operates each zone in a low-power state but does not shut down power to each zone. This allows the system  100  to be quickly powered up to its full operation state quickly. 
     As briefly described above, the adhesive application system  100  is configured to apply a liquid adhesive (i.e. an adhesive that is liquid at room temperature). The adhesive has a carrier that can be volatilized with heat (e.g. water, solvent, or mixtures thereof). The adhesive application system  100  can be used to apply any liquid adhesive  103  that uses a carrier (i.e., water based, solvent based, etc.). The adhesive  103  can be an emulsion, a dispersion or a solution and can include any polymer type including homopolymers and polymers comprising one or more monomer (e.g., copolymers, terpolymers, etc.). The water based liquid adhesive can be borated (i.e. boric acid can added to it). 
     Some common monomers that can be used to make water-based adhesives include, e.g., vinyl acetate, vinyl chloride, vinyl acrylics, vinylidene chloride, ethylene, ethyl acrylate, ethyl hexyl acrylate, butyl acrylate, methyl acrylate, methyl methacrylate, styrene, and urethanes. The adhesive  103  can further use any protection system (i.e. be stabilized in a number of different ways) including polyvinyl alcohol, surfactant and cellulose. 
     The viscosity of the adhesive  103  can be no greater than about 5000 cps, no greater than about 2500 cps, no greater than about 2000 cps, no greater than about 1600 cps, between about 300 and about 2000 cps, or even between about 500 and about 1600 cps when tested at 26° C. using a Brookfield Viscometer (20 rpm, spindle=3). The solids of the adhesive  103  can be from about 45% to about 65%, from about 45% to about 60%, or even from about 45% to about 55% by weight. 
     In one embodiment, the adhesive  103  can be a water-based emulsion including polyvinyl alcohol as the protection system (i.e., the water-based adhesive is polyvinyl alcohol stabilized). 
     The polymer present in the emulsion can be a polyvinyl acetate (PVA) homopolymer, a vinyl acetate-ethylene (VAE) copolymer, a vinyl acrylic, a styrene acrylic, a polychloroprene, a block copolymer, a styrene butadiene rubber, an olefin or a starch based polymer. 
     The water-based emulsion can include a plasticizer. The plasticizer can comprise phthalates (e.g., diisodecyl phthalate (DIDP), diisooctyl phthalate (DIOP), etc.), benzoates (e.g., diethylene glycol dibenzoate, dipropylene glycol dibenzoate, and mixtures thereof) and triacetin. The plasticizer can be present at from about 3% to about 20% by weight, from about 5% to about 15% by weight, or even from about 7% to about 13% by weight. 
       FIG. 20  shows a chart containing characteristics of example adhesives  103  that can be used with the adhesive application system  100 . 
     The following test methods were used to generate the data in  FIG. 20   
     Solids 
     Total solids of the polymer emulsion was determined by first weighing an aluminum weighing dish to the nearest milligram. The polymer emulsion to be tested was mixed or stirred to insure homogeneity. One gram+/−0.2 grams of the polymer emulsion was added to the dish and dried in an oven for 1.5 to 2.5 hours at a temperature of 130° C. The sample was cooled for approximately 5 minutes and reweighed. An average of at least two samples not differing by more than 0.3% was recorded. 
     Viscosity 
     Viscosity is determined using Brookfield viscometer model RVT at 20 rotations per minute. An appropriate spindle is chosen to obtain an accurate reading based on the anticipated viscosity of the composition and the manufacturer&#39;s recommendations. The sample composition is maintained at 25° C. and the measurement is taken within 1 hour of making the composition. The results are reported in centipoise (cps). 
     Set Time 
     The adhesive was applied in a spray pattern to a piece of recycled chip board (recycled content of 40-60%) utilizing the claimed application system with the following conditions: adhesive temperature: 65.6° C. (150° F.), air temperature: 190.5° C.-204.4° C. (375-400° F.); gun pressure: 70 psi: atomization pressure: 2-30 psi. Immediately after application, a second piece of chip board was pressed into place using hand pressure. The Set Time was determined by pulling the bond at various times after formation until 100% of the bond line resulted in fiber tear from the chip board. 
     Spray Pattern 
     The spray pattern observed during the set time test was given a ranking on a scale from 1 (poor) to 10 (excellent). A score of 10 was given to an adhesive exhibiting a finely atomized spray with no globules (larger bits of adhesive). Lower numbers indicate that more globules were present. 
     Nozzle Clogging 
     Nozzles were merely observed during spraying and if they clogged were give a Yes and if they did not clog were given a No. 
     The various embodiments described above are provided by way of illustration only and should not be construed to limit the claims attached hereto. Those skilled in the art will readily recognize various modifications and changes that may be made without following the example embodiments and applications illustrated and described herein, and without departing from the true spirit and scope of the following claims.