Abstract:
Systems and methods of fluid conveyance and/or heating are provided. A system according to the present invention provides improved selected localized or distributed fluid heating, master/slave dual pump control, hose construction, and/or a combination thereof. Another system according to the present invention provides a portable plural fluid heating apparatus, which may be located closer to a fluid application point than a fluid source, thereby minimizing the distance required to be traveled by fluid after heating.

Description:
RELATED APPLICATION 
       [0001]    This application claims the benefit of Provisional patent application Ser. No. 61/622,350 filed 10 Apr. 2012. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Embodiments according to the present invention relate generally to fluid handling, and more particularly to multi-component fluid handling and heating. Plural-component fluid handling is common in applications such as spray elastomers, which may be used in spray coating applications, such as spray foam insulation (e.g., polyurethane (isocyanate and resin)), polyurea coatings, polyethylene, polyaspartic (e.g. polyisocyanate and polyaspartic ester), polyurethane/urea foams, etc. Fixed-ratio, dual component proportioners have been known for many years. In fact some prior component proportioners have even included heating elements so as to heat fluid prior to mixing so as to desirably adjust fluid viscosity to provide a more thorough mixture for spraying or other application. 
         [0003]    There remains room for improvement in the art of fluid handling, and especially in the art of plural component fluid handling prior to mixture, such as improved selective heating, dual pump control, hose construction, and/or a combination thereof. 
       SUMMARY OF THE INVENTION 
       [0004]    Systems and methods according to the present invention provide improved selective heating, dual pump control, hose construction, and/or a combination thereof. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a top plan view of a first embodiment of a system according to the present invention. 
           [0006]      FIG. 2A  is a diagram of an embodiment of a fluid flow path according to the present invention. 
           [0007]      FIG. 2B  is a cross-section view taken along lines  2 B- 2 B of  FIG. 2A . 
           [0008]      FIG. 2C  is a cross-section view taken along lines  2 C- 2 C of  FIG. 2A . 
           [0009]      FIG. 3  is an electrical schematic of an embodiment of a control panel according to the present invention. 
           [0010]      FIG. 4  is a partial perspective view of the system of  FIG. 1 . 
           [0011]      FIG. 5  is a partial front elevation view of an embodiment of a user interface according to the present invention. 
           [0012]      FIG. 6A  is a perspective view of an embodiment of a portable fluid heater according to the present invention. 
           [0013]      FIG. 6B  is an internal top plan view of the embodiment of  FIG. 6A . 
           [0014]      FIG. 7  is an electrical schematic of the embodiment of  FIG. 6A . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0015]    Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention. 
         [0016]    Turning now to the figures,  FIG. 1  provides a plan view of a fluid handling system  100  according to the present invention. Also with reference to  FIG. 2A , generally, the preferred system  100  includes a fluid supply  110 , a fluid distribution system  120 , a fluid conveyor  150 , and an electrical operational interface  170 . The fluid supply  110  comprises at least one, but preferably a plurality of fluid vessels  112 , each of which may include a siphoning mechanism (not shown), as is known in the art for drawing fluid therefrom. The fluid distribution system  120  generally includes at least one, but preferably a plurality of pumps  122 , each of which is in fluid communication with a fluid vessel  112 . The fluid conveyor  150  generally comprises at least hose  152 , which may include one or more conduits  154  each configured to receive fluid from a pump  122 , and a nozzle  160 . The electrical operational interface  170  may comprise one or more electrical component cabinets  172 , through which electricity flows from a generator  174  or power mains, is controlled, and then delivered to various electrical components, as explained further below. The system  100  may be housed in a movable shell, such as an enclosed trailer  101 , disposed on one or more wheeled axles (not shown). The trailer  101  preferably includes a hitch mechanism  102  configured to mechanically cooperate with a ball hitch or hitch receiver member coupled to a motorized vehicle for easy transport. The trailer  101  may have a plurality of internal cavities  103   a,b,  each of which may be accessed by one or more manway doors  104 . 
         [0017]    Turning now to  FIGS. 2A-2C , a fluid flow path through an embodiment of a system according to the present invention may be explained. Generally, the system is configured to transport fluid from the fluid supply  110  to the nozzle  160 . In a preferred embodiment, as shown, the system may be configured to convey a plurality of fluids, each from a separate fluid supply vessel  112   a,b,  to the nozzle  160 , such as a plural component mixing gun  162 . In the preferred embodiment, a first pump  122   a  has an input line  124   a  in fluid communication with a first fluid vessel  112   a.  The first pump  122   a  has an output line  126   a,  which may form a component of the fluid conveyor  150 , or as shown, may convey the fluid from the first vessel  112   a  to a primary fluid heater  130 . A second pump  122   b  has an input line  124   b  in fluid communication with a second fluid vessel  112   b.  The second pump  122   b  has an output line  126   b,  which may form a component of the fluid conveyor  150 , or as shown, may convey the fluid from the second vessel  112   b  to the primary fluid heater  130 . The first pump  122   a  and the second pump  122   b  may be operated separately, but advantageously are operated in a master/slave configuration  128 , whereby blend ratios of a plurality of fluids may be controlled from a single pump control panel. 
         [0018]    As shown, in a preferred system, a plurality of fluids is conveyed through a primary fluid heater  130  prior to being presented to the fluid conveyor  150 . The primary heater  130  preferably includes an aluminum parallelepiped heater body  132  including at least one, but preferably a plurality of parallel U-shaped heating cavities  134 , extending between a first control end  133  and a second fluid end  135  thereof. On the fluid end  135  of the heater body  132 , each heating cavity  134  has an input end  136  in fluid communication, such as through a quick-connect fitting  137 , with a pump output line  126 , and has an output end  138  in fluid communication, such as through a quick-connect fitting  139 , with a fluid conveyor conduit  154 . Most preferably, the input end  136  and output end  138  of each heating cavity is provided on the fluid end  135  of the heater body  132  to provide easy fluid connectivity access. The fluid is heated within the heating cavities  134  by electrically resistive heating elements  140 , which are electrically coupled to the electrical operational interface  170  through connectors  142  and/or wires  144 . Disposed in fluid communication with preferably each heating cavity  134  is a thermocouple  146  or other temperature sensor or transducer, which may be used to generate an electrical representation of the temperature, or an approximation of the temperature, of the respective fluid. The thermocouple  146  preferably extends through an aperture formed through a surface of the heater body  132  and into the output end  138  of a cavity  134 . The thermocouple  146  is electrically coupled to the electrical operational interface  170  through connectors and/or wires  147 . A heater body thermocouple  148  may also be provided, to enable the measurement or approximation of the temperature of the heater body  132  for safety reasons. The heater body thermocouple  148  is electrically coupled to the electrical operational interface  170  through connectors and/or wires  149 . 
         [0019]    A cross-section of a preferred fluid conveyor hose  152 , which runs for at least fifty feet, but more preferably about 200 feet, may be seen in  FIG. 2C . The hose  152  preferably includes a first fluid flow conduit  154   a  and a second fluid flow conduit  154   b,  generally secured by an adhesive conduit jacket  155  extending therearound. Conventionally, in prior plural conduit hoses, the conduit jacket is structurally bonded to the plurality of conduits, thus rendering it nearly impossible to change a single conduit in the event of failure (e.g., cracking or bursting) or clogging. For instance, some fluids that may be conveyed with systems according to the present invention may react with air or oxygen so as to form a solid material. If hoses are not properly cleaned after use, air or oxygen may eventually permeate the hose or enter at fitting locations and clog such conduits. In such event, in prior hoses, the entire hose including a plurality of conduits had to be disposed of, while only a single one of the multiple conduits may have been compromised. By providing an adhesive conduit jacket  155  according to this embodiment according the present invention, such as an adhesive tape, the conduit jacket  155  may be easily removed and a single conduit  154  may be replaced upon failure or clogging, rather than requiring disposal of the entire hose. Other easily removable conduit jackets  155  may likewise be utilized, preferably along a majority of the length of the hose  152 , or at discrete locations along the hose  152 . 
         [0020]    Extending completely circumferentially around the conduit jacket  155  is preferably a scuff jacket  158 , which may be formed from a woven tubular plastic material. The scuff jacket  158  may be secured at each end thereof to the conduits  154 , the conduit jacket  155 , or both. In addition to or alternatively to the primary fluid heater  130 , a secondary fluid heater may be utilized. In the depicted embodiment, the secondary fluid heater comprises one or more heat tape lengths  156  preferably sandwiched between the fluid flow conduits  154  and generally held in respective position thereto by the conduit jacket  155  previously described. If a plurality of heat tape lengths  156  are provided, they are preferably disposed in a serial arrangement (i.e., end-to-end) to allow for selective heating control along portions of the hose  152 . 
         [0021]      FIG. 3  provides an electrical schematic of a heating control circuit  200  according to the present invention. Generally, so long as the heater body thermocouple  148 , which may be or be connected to a temperature activated switch, is sensing a normal heater body operating temperature (i.e. not too hot), then the contactor CR 1  will be activated, thereby providing electrical power therethrough, and also through circuit breakers CB 3  and CB 4  to the heating elements  140  in the primary heater  130 . The heating elements  140  are gated with power, such as by one or more proportional-integral-derivative (PID) controllers PM 6 , which receive input from the fluid thermocouples  146 . Each PID controller then respectively turns a solid state relay SCR 1 , 2  on and off as needed to supply power to the wires  144  electrically coupled to the heating elements  140 . A preferred PID controller is an EZ-ZONE® PM Express PID Controller available from Watlow Winona, Inc. of Winona, Minn. 
         [0022]    The circuit  200  also preferably provides circuit breaker protected power to the pumps  122  and to secondary heater controllers  202 . The secondary heater controllers  202  preferably receive temperature feedback from the hose  152 , thereby gating power its respective heat tape length  156 . A preferred secondary heater controller  202  is an A419 Series Electronic Temperature Control available from Johnson Controls, Inc., of Milwaukee, Wis. 
         [0023]    The circuit  200  is also preferably provided with a safety circuit  220 , which may be activated by the tripping of the temperature activated switch controlled by or as a result of the heater body thermocouple  148 . The safety circuit  220  generally operates as follows. If the temperature activated switch opens, then CR 1  is deactivated, which means power is removed from the heater lines HL 1 , 2 , regardless of the demand for heat from the PID controllers. Warning indicators such as a horn  222  and a light  224  may be activated, and a latching circuit  226  may be provided to allow clearing of one or both of the warning indicators. As shown, upon depression of a normally open push button switch  228 , CR 2  is activated, thereby disconnecting the horn  222  and light  224 . Alternatively, the light  224  may be connected on the other side of CR 2 , such that the button  228  clears only the horn  222 , and the light  224  remains lit until the warning situation is cleared by the heater body thermocouple  148 . Once the temperature activated switch senses a normal (i.e. low enough) heater body temperature through the heater body thermocouple  148 , then CR 1  is reactivated and the warning condition is cleared. The circuit  200  is preferably provided in or supported on at least one wiring panel  172 . However, in some circumstances it may be desirable to, for instance, separate the circuit breakers into a wiring panel of their own. 
         [0024]      FIG. 4  generally provides an elevation view of an arrangement of the system of  FIG. 1 . 
         [0025]      FIG. 5  depicts a preferred electrical system user interface  174  according to the present invention. The user interface  174  preferably includes user input devices, such as buttons  176  on the PID controllers PM 6 , the warning clearing button  228 , and a main disconnect switch DS 1 . The user interface  174  further preferably includes user output devices such as visual displays  178  on the PID controllers PM 6 , the warning horn  222 , and the warning light  224 . 
         [0026]    In use, a fluid path is established between a fluid supply vessel  112  and a pump  122 , and between the pump  122  and a nozzle  160 . The pump  122  draws fluid from the fluid supply vessel  112  and delivers it at a desired pressure to the nozzle  160 . In a preferred use, two fluid supply vessels  112   a,b  each is coupled to a separate pump  122   a,b,  respectively. From the pumps  122   a,b,  one or both fluids are fed through a primary heater  130 , through a length of conduit  152  and to the nozzle  160  in or at which the fluids are mixed just prior to or during spraying or other application. Even more preferably, the conduit  152 , which may have a plurality of distinct fluid flow paths, is heated along at least a portion of its length. Indeed, separate portions of the conduit  152  may be heated, such as by heat tape sections  156 , which may be placed in a longitudinally serial manner along the conduit  152 . In this manner, each fluid may be selectively heated to approximately a desired temperature within the primary heater  130 , and/or both fluids may be heated to approximately a desired temperature in the conduit  152  by one or more heat tape sections  156 . A desired fluid temperature may be programmed into the respective PID controller PM 6  for each fluid, a desired fluid temperature may be programmed into the secondary heater controllers  202  for one or more tape section  156  provided, and a desired fluid pressure may be programmed into or selected on each pump  122 . The fluid pressure may be selected individually, or one of the pumps may control the second pump as a slave device. If in a master/slave control arrangement, the master pump may have preprogrammed modes of operation to enable preset mixtures of the fluids, where such preset mixtures may depend upon the nature or type of the fluids to be mixed, ambient temperature, ambient humidity, and/or distance from pump to fluid application location. 
         [0027]    It is to be understood that the primary heating system (primary heater  130  plus control circuitry) described thus far is mounted in a stationary wiring cabinet  172  that may be mounted in a movable trailer unit  101 . However, it may be desirable to provide a portable primary heating unit, such that the primary heating is performed at a location remote from (outside of) the structure that otherwise houses a fluid supply and/or fluid distribution mechanism or pump. An embodiment of a portable or remote fluid heating system  300  is shown with reference to  FIGS. 6A-7 , where like reference numerals refer, in at least utilitarian terms, to the same or similar structure to the system  100  described above. The system  300  generally includes a container having a lid  302  mateable to a base  304 . The base  304  preferably defines at least one cavity, but preferably at least a heating cavity  306  and a control cavity  308 . Disposed within the heating cavity  306  is a primary heater  130 , as previously described. Access to fluid inputs and outputs of the heater  130  may be provided through a first fluid interface  310  and a second fluid interface  312 . While various configurations are possible, the fluid interfaces  310 ,  312  are preferably provided on two different faces of the base  304 , preferably at about ninety degrees to each other, proximate to a corner of the base  304 . Each fluid interface  310 ,  312  may be respectively color coded (e.g. one red and one blue) to enhance connection reliability. Extending through a wall of the base  304  and into the heating cavity  306  is a fan assembly  314 . The fan assembly  314  draws outside air into the heating cavity  306  in a first direction  316  through one or more apertures  318  formed through the wall of the base  304 , and blows heated air out of the heating cavity  306  in a second direction  320  that is substantially opposite the first direction  316 . 
         [0028]    In the control cavity  308  are preferably mounted some of the electrical components of the circuit of  FIG. 7 . The disconnect switch DS 1  provided on the outside of the cover  302  operates through a mechanical cooperation of a male member  322  and a female member  324  to enable rotation of the switch. Power is supplied to the electrical components through an electrical cable  326 , which is coupled to a power supply, which may provide power that is locally generated or supplied via standard power mains. 
         [0029]    Fixedly situated between the heating cavity  306  and the control cavity  308  is an insulation barrier  328 , which preferably extends through an entire height of the heating cavity  306  so as to shield the electrical components from excessive ambient heat from the primary heater  130 . Additionally or alternatively, a second fan assembly (not shown) may be arranged so as to vent the control cavity  308  similar to how the fan assembly  314  vents the heating cavity  308 . 
         [0030]    The circuit schematic provided in  FIG. 7  is identical to the schematic in  FIG. 3 , without the power feed to the fluid distribution system  120 . Additionally, the circuitry related to the secondary heater controllers  202  may be removed if desired. A secondary fluid heater, such as the heat tape sections  156  may not be required in conjunction with the portable heater system  300  of  FIG. 6A  because the heater may be located and used proximate to a fluid application point, thereby shortening the distance required to be traversed by the fluid conduit  152 . That is, if fluid is heated in a trailer, or closer to a fluid supply than to a fluid application location, a generally recognized conduit length is about 200 feet. However, if a portable heating system  300  is used, and located closer to the fluid application location than the fluid supply, then a shorter hose, such as 20 feet to about 50 feet may be used, thereby potentially eliminating the need for any secondary heating requirement. 
         [0031]    In use, the portable heating system  300  may be located closer to the fluid application location than the fluid supply. Fluid supply inputs at a desired pressure may be coupled to respective inputs on the fluid interfaces  310 ,  312 , and the outputs may be placed in fluid communication with a fluid flow conduit  152 . Like with the system  100  described above, a desired fluid temperature may be programmed into the respective PID controller PM 6  for each fluid, a desired fluid temperature may be programmed into the secondary heater controllers  202 , if provided, for one or more tape section  156  provided, and a desired fluid pressure may be programmed into or selected on each pump  122 . The fluid pressure may be selected individually, or one of the pumps may control the second pump as a slave device. If in a master/slave control arrangement, the master pump may have preprogrammed modes of operation to enable preset mixtures of the fluids, where such preset mixtures may depend upon the nature or type of the fluids to be mixed, ambient temperature, ambient humidity, and/or distance from pump to fluid application location. 
         [0032]    The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. For instance, while the system has been described with respect to usage with at least one and preferably two fluids, it is to be understood that such usage is exemplary, and more fluids may be utilized. While the preferred embodiment has been described, the details may be changed without departing from the invention.