Patent Document

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0001]    This invention was made with U.S. Government support under grant number NSF Grant No. EEC-0332723 awarded by the National Science Foundation. The Government has certain rights in this invention. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a device and system for coating pipes and ducts. In particular, the device of the invention utilizes a duct coating applicator capable of navigating small ducts and is used with a system that provides data to an operator and to a remote recipient. 
       BACKGROUND OF THE INVENTION 
       [0003]    There are numerous patents and publications describing devices and systems purporting to inspect, repair, and seal pipes and ducts. However none of these devices and systems can navigate and treat small (e.g., 6 inch in diameter) HVAC ducts with elbows and transitions. In addition, none of these devices have been packaged in systems that enable regional and national franchising. This disclosure describes a device and system to meet the objectives. 
       SUMMARY OF THE INVENTION 
       [0004]    The duct coating system uses a self-propelled remotely operated tracked or wheeled vehicle (ROV) to conduct initial and final inspections and to video record those inspections of a duct interior. Preferably, a camera is also placed on the applicator head of the duct coating applicator to monitor the coating process and to track the location of the application head. This is particularly important when applying additional coats of material at specific locations in a duct. 
         [0005]    The applicator of the duct coating system is preferably passive, i.e., towed. The duct coating applicator may be provided with a scissor-type carriage or, alternatively, may be mounted on an ROV similar to the inspection ROV to position the nozzle and to assist the capstan or winch in propelling the duct coating applicator through the duct. 
         [0006]    The ROV may also be used to string a tow line through the duct to be attached to the applicator head. The tow line is used to pull the applicator head and material supply lines through the duct prior to coating the duct. The duct coating applicator of the invention is preferably a towed device that conveys a dynamic mixer for plural compounds, and a metering nozzle capable of uniformly coating the inside of the duct/pipe. The duct coating applicator can transport a single component nozzle for priming the duct, cameras for inspecting the duct, and devices to scarify the walls of the duct. The duct coating applicator can also convey an orientable nozzle to repair holes in the duct by injecting plural fluid compounds into cavities. 
         [0007]    The plural fluid nozzle and transporter works as follows. The duct coating applicator consists of a cylindrical body to which are attached four 4-bar extendable arms with wheels. These arms can extend or contract to follow the inside of a duct or pipe while positioning the body in the center of the duct. An annular air cylinder contracts or extends the arms. The cylinder is counterbalanced by a set of extension springs to control the forces exerted by the wheel against the wall of the duct. In an alternative version, springs extend the arms and arms are contracted manually. 
         [0008]    The duct coating system of the invention is a three fluid system, e.g., air, resin, and, in the case of polyurea, isocyanate. Preferably, the flow rates of each pump of the resin and isocyanate may be separately controlled because of the large ranges in viscosity of the two materials as a function of temperature. The two parts of the plural fluid are metered separately into the rear of the nozzle system. The two parts of the fluid are combined by impinging the two streams. Further mixing occurs in the slotted or round orifices. An adjustable nozzle produces a cone shaped pattern or radial fan shaped pattern of the mixed materials to coat the inside of the duct. Viscosity is controlled by resistance heaters (not shown). The transporter is towed through the duct by its supply hoses with speed controlled by a capstan (not shown). Servos controlled by a central computer drive the capstan plural fluid pumps, transporter arm, heaters, and other devices in the system. The system of the invention is capable of conveying a nozzle through HVAC ducts of a variety of sizes. The system facilitates mixing, atomizing, and applying plural compounds to seal and provide structural integrity to the duct. The duct coating system provides a means to inspect, clean, prepare, prime, coat, and document the sealing process. The system also provides a means to repair and disinfect a duct/pipe installation. 
         [0009]    The duct coating system includes the capacity to transmit to a franchiser and franchisee statistics obtained during the sealing of a duct system in a home. This feature provides for the ability for automated accounting and billing for a franchisee and franchiser. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a partial sectional drawing of a transport and plural fluid nozzle. 
           [0011]      FIG. 2  shows the transport and plural product nozzle of  FIG. 1  navigating a 6 inch duct 90 degree elbow. 
           [0012]      FIG. 3  shows a transporter and plural product nozzle with guide wheel arm expanded to navigate 10 inch diameter ducts. 
           [0013]      FIG. 4  shows the transporter of the invention in two configurations. 
           [0014]      FIG. 5  shows steps for a method of use of the duct coating system of the invention. 
           [0015]      FIG. 6  is a block diagram of a computer controlled application system and a motion control system to allow a plural component nozzle transporter to be positioned in the duct. 
           [0016]      FIG. 7  is a controller block diagram for the duct coating system of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]    Referring now to  FIGS. 1 and 2 , shown is a duct coating applicator or applicator head of the invention designated generally  10 . Duct coating applicator  10  is a towed device that is capable of navigating a duct  11  ( FIGS. 2 ,  4 ). Duct  11  may be of various sizes, e.g., 6 inch ducts, duct elbows, transitioning and wyes. Duct coating applicator  10  is capable of expanding for use in larger ducts, e.g., 10 to 12 inch diameter duct systems. Duct coating applicator  10  has a cylindrical body  12 . Cylindrical body  12  has an outer member  14  and a core member  16 . Cylindrical body  12  additionally has an inlet end  18  and an outlet end  20 . Outer member  14  defines an annular chamber  22  ( FIG. 1 ) for receiving an annular piston  24  for regulating extension of pairs of extension arms  70 ,  92 ,  114 ,  136 , discussed below. Core member  16  has an inlet end  26  and an outlet end  28  ( FIG. 1 ). Core member  16  defines a first longitudinal passageway  30  and a second longitudinal passageway  32 . First longitudinal passageway  30  has a first inlet  34  and second longitudinal passageway  32  has a second inlet  36 . Each of first inlet  34  and second inlet  36  communicate with inlet end  26  of core member  16 . First passageway  30  has a first outlet  38 . Second passageway  32  has a second outlet  40 . Each of first outlet  38  and second outlet  40  communicate with transverse combining passageway  42 . Transverse combining passageway  42  passes combined fluids to impinging mixing chamber  44  for passing fluid through a slotted or radially drilled orifice core mixer  46 . 
         [0018]    Slotted member  48  is located in slotted core mixer  46  adjacent to an outlet end of impinging mixing chamber  44 . 
         [0019]    Outlet cap  52  is threadably received on outlet end  28  of core member  16 . Outlet cap  52  receives stem  54  that defines exit passageway  56 . 
         [0020]    Adjustable nozzle  58  is positioned on an outlet end of stem  54  for dispersing fluids traveling through exit passageway  56 . 
         [0021]    Inlet member  62  is affixed to inlet end  18  of cylindrical body  12 . Inlet member  62  defines first threaded inlet  64  and second threaded inlet  66 . First threaded inlet  64  communicates with inlet  34  of first longitudinal passageway  30 . First threaded inlet  64  receives a first component of a plural fluid. Second threaded inlet  66  is in communication with second inlet  36  of second longitudinal passageway  32 . Second threaded inlet  66  receives a second component of a plural fluid. 
         [0022]    Slider  68  is slidably received on and surrounds outer member  14 . Slider  68  interacts with annular piston  24  for being longitudinally displaced thereby. 
         [0023]    First pair of extension arms  70  has a first arm  72  having a proximate end  74  pivotally affixed adjacent to inlet end  18  of cylindrical body  12 . First pair of extension arms  70  has a second arm  76  having a proximate end  78  pivotally affixed to extension slider  68 . First arm  72  and second arm  76  of first pair of extension arms  70  are pivotally affixed to one another at point  80  located approximately at a midpoint of each of first arm  72  and second arm  76 . 
         [0024]    First wheel  82  is affixed to a distal end of first arm  72 , and second wheel  86  is affixed to a distal end of second arm  76  of first pair of extension arms  70 . First extension spring  90  has a first end affixed to outer member  14  and a second end affixed to extension slider  68  for biasing extension slider  68  toward inlet end  18  of cylindrical body  12 , thereby biasing first wheel  82  and second wheel  86  away from cylindrical body  12  via scissor action of first arm  72  and second arm  76 . 
         [0025]    Second pair of extension arms  92  has a third arm  94  having a proximate end  96  pivotally affixed to inlet end  18  of cylindrical body  12 . Second pair of extension arms  92  has a fourth arm  98  having a proximate end  100  pivotally affixed to extension slider  68 . Third arm  94  and fourth arm  98  of second pair of extension arms  92  are pivotally affixed to one another at point  102  located approximately at a midpoint of each of third arm  94  and fourth arm  98 . Third wheel  104  is affixed to a distal end of third arm  94  and a fourth wheel  108  is affixed to a distal end of fourth arm  98  of second pair of extension arms  92 . 
         [0026]    A third pair of extension arms  114  has a fifth arm  116  having a proximate end  118  pivotally affixed to inlet end  18  of cylindrical body  12 . Third pair of extension arms  114  has a sixth arm  120  having a proximate end  122  pivotally affixed to extension slider  68 . Fifth arm  116  and sixth arm  120  of third pair of extension arms  114  are pivotally affixed to one another at point  124  proximate a midpoint of each of fifth arm  116  and sixth arm  120 . Fifth wheel  126  is affixed to a distal end of fifth arm  116  and sixth wheel  130  is pivotally affixed to sixth arm  120  of the third pair of extension arms  114 . 
         [0027]    Second extension spring  134  ( FIG. 4 ) has a first end affixed to outer member  14  and a second end affixed to extension slider  68  for biasing extension slider  68  toward inlet end  18  of cylindrical body  12 , thereby biasing fifth wheel  126  and sixth wheel  130  away from cylindrical body  12  via scissor action of fifth arm  116  and sixth arm  120 . 
         [0028]    A fourth pair of extension arms  136  has a fifth arm  138  having a proximate end  140  pivotally affixed to inlet end  18  of cylindrical body  12 . Fourth pair of extension arms  136  has a sixth arm  142  having a proximate end  144  pivotally affixed to extension slider  68 . Fifth arm  138  and sixth arm  142  of fourth pair of extension arms  136  are pivotally affixed to one another at point  146  proximate a midpoint of each of fifth arm  138  and sixth arm  142 . Fifth wheel  148  is affixed to a distal end of fifth arm  138  and sixth wheel  152  is pivotally affixed to sixth arm  142  of the fourth pair of extension arms  136 . 
         [0029]      FIG. 5  is a block diagram of the electronics and control system. The elements in the system describe some of its functionality. The block diagram shows a computer controlled application system and a motion control system to allow the plural component nozzle and transporter to be positioned in the duct. 
         [0030]    Referring now to  FIG. 5 , in practice, the method of sealing pipes or ducts comprises the steps of mounting video camera  344  ( FIG. 6 ) on duct coating applicator  10 . Duct technician  201  moves duct coating applicator  10  through duct  11 , recording a video of an inside of duct  11 , as shown in step  202 . The video information is then transferred and stored onto a storage medium, as shown in step  204 . The video recording is then reviewed with customer  205 , as shown in step  206 . Duct coating applicator  10  may then be moved through duct  11  for spraying plural compounds on an interior of duct  11  for sealing and providing structural integrity to duct  11  as shown in step  208 . A bill may then be printed at the duct location for the customer as shown in step  210 . The video recording is then transmitted to a remotely located franchisee and franchisor as shown in step  212 . Job statistics are additionally transmitted to the local franchisee  214  and to the franchiser  216 , as shown in step  218 . 
         [0031]    The duct coating applicator  10  may be of the type disclosed in U.S. patent application Ser. No. 12/723,425 entitled “Mixing Nozzle for Plural Component Materials,” which is hereby incorporated by reference. 
         [0032]    Referring now to  FIG. 6 , shown is duct coating system  300 . Duct coating system  300  includes a duct coating applicator  10  and controller  302 . A pump speed setting  304  is provided on controller  302  for adjusting the pump speed. Carriage speed setting  306  is provided on controller  302  for adjusting the travel speed of duct coating applicator  10  within duct  11 . 
         [0033]    First resin tank  308  is provided for receiving a quantity of a first resin. First reservoir  310  is in communication with and receives resin from first resin tank  308 . First reservoir temperature sensor  330  is provided to read temperature of the resin in first resin tank  308 . First temperature sensor  330  communicates temperature data with controller  302 . First temperature indicator  312  is provided on controller  302  for indicating temperature of the resin in first resin tank  308 . 
         [0034]    First pump  314  communicates with first resin tank  308  for receiving resin therefrom. First resin supply line  316  is provided for receiving resin from first pump  314  and for delivering resin to duct coating applicator  10 . First resin pressure sensor  318  communicates with first resin supply line  316  for measuring pressure in first resin supply line  316 . First resin pressure sensor  318  communicates pressure data to controller  302 . First resin supply pressure indicator  320  indicates the pressure readings of second resin pressure sensor  318  as instructed by controller  302 . 
         [0035]    Second resin tank  328  is provided for receiving a quantity of a second resin. Second reservoir  311  is in communication with and receives resin from second resin tank  328 . Second reservoir temperature sensor  331  is provided to read temperature of the resin in second resin tank  328 . Second temperature sensor  331  communicates temperature data with controller  302 . Second temperature indicator  332  is provided on controller  302  for indicating temperature of the resin in second resin tank  328 . 
         [0036]    Second pump  334  communicates with second resin tank  328  for receiving resin therefrom. Second resin supply line  336  is provided for receiving resin from second pump  334  and for delivering resin to duct coating applicator  10 . Second resin pressure sensor  338  communicates with second resin supply line  336  for measuring pressure in second resin supply line  336 . Second resin pressure sensor  338  communicates pressure data to controller  302 . Second resin supply pressure indicator  340  indicates the pressure readings of second resin pressure sensor  338  as instructed by controller  302 . 
         [0037]    Duct diameter proximity sensor  342  is provided on duct coating applicator  10  for measuring a diameter of duct  11  through which duct coating applicator  10  is traversing. Duct diameter proximity sensor  342  is in communication with controller  302 . 
         [0038]    Video camera  344  is located on duct coating applicator  10 . Video display  346  is provided for receiving video signal from video camera  344  on duct coating applicator  10  via a data signal cable  348 . Video recorder  350  is in communication with video display  346  and with data signal cable  348 . 
         [0039]    Winch  352  engages first resin supply line  316 , second resin supply line  336  and data signal cable  348  for pulling duct coating applicator  10  through duct  11 . Carriage variable speed drive  354  is in communication with winch  352  for directing a speed with which winch  352  pulls duct coating applicator  10 . Carriage variable speed drive  354  receives a carriage speed signal  356  from controller  302 . 
         [0040]    A remote jobs statistics collection computer  358  is provided at a location remote from duct coating applicator  10  and controller  302 . An external communicator, such as cell modem  360 , is in communication with controller  302  for passing job statistics to remote jobs statistics collection computer  358 . 
         [0041]    Referring now to  FIG. 7 , controller  302 , also shown in  FIG. 6 , is provided wherein a user may input pump speed setting  304  (see also  FIG. 6 ) and a carriage speed setting  306  (see also  FIG. 6 ) and may select between automatic or manual setting  400 . Duct coating applicator  10  ( FIGS. 1-5 ) may be provided with a duct diameter measuring device, e.g., duct diameter proximity sensor  342  ( FIG. 6 ). Duct coating applicator  10  is additionally provided with a transmitter so that a duct diameter may be transmitted to controller  302  when automatic/manual setting  400  of controller  302  is set for automatic operation. 
         [0042]    The overall methodology of the controller  302  is that of a feed forward system. In  FIG. 6  it can be seen that user inputs may be provided to or by the controller  302 . Control operations occur within the controller  302  that are then passed out of the controller to duct coating applicator  10 . The behavior of duct coating applicator  10  may be modeled by the system illustrated to the right side of controller  302  in  FIG. 7 . Based in part upon signals received back from the duct coating applicator  10 , the control outputs can be modified by the controller  302  as needed. In actuality, changes implemented by the controller  302  will not occur instantaneously throughout the rest of the system. However, given the relatively small size and speed of the duct coating applicator, and relatively small volume of the pump, it is appropriate in some embodiments to consider the system statically as shown in  FIG. 7 . 
         [0043]    In operation of the present embodiment, a signal from the pump speed setting  304  is summed with a G FF     —     carriage  signal, which is derived in part based on the carriage speed setting  306  as described below. These signals are also summed with a G FF     —     dia  signal, which is derived from the duct diameter, and also described below. The result of this summation is the Pump Speed Signal from the control system  302 . The Pump speed signal K pump  can be considered as a flow rate signal K flow  governed by the equation K flow =1/πD ss v ss . Here D ss  is the pipe diameter and V ss  is the velocity of the duct coating applicator  10  in the pipe or duct. Hence, for a constant coating thickness, the flow rate is inversely proportional to the diameter and velocity. 
         [0044]    The flow rate signal K flow  is summed with the duct diameter as K dia , which follows the equation K dia =−Q/πD 2   ss v ss . Here Q is the volumetric flow rate. Hence, to maintain a constant coating thickness T, the volumetric flow rate Q must remain in proportion to the product of the diameter squared and the velocity. In the present system, the actual measured duct diameter is reported to the controller  302  by the duct coating applicator  10 . This measurement is scaled by a feed forward gain factor G FF     —     dia  to account for changes in the pipe diameter as the duct coating applicator  10  moves. When the system is in automatic mode, this factor will be utilized to control the pump speed signal thus feeding forward through the system. 
         [0045]    In producing a thickness of coating T, K flow  and K dia  are summed with K carr  or K carriage  which follows the following equation: K carr =−1/πD ss v 2   ss . K carr  is a carriage speed signal from the controller  302 . Thus it will be appreciated that carriage speed, as relating to thickness T, is directly proportional to volumetric flow and inversely proportional to diameter and velocity. The final thickness T may be computed from the system using the equation T=Q/πDv. 
         [0046]    Based on the foregoing, it will be appreciated that in operation both the pump speed and carriage speed may be controlled by the controller  302  to produce a uniform and desired coating thickness T. In the present embodiment, the carriage speed signal is produced by the controller  302  and fed to duct coating applicator  10 . The pump speed is derived based upon the carriage speed to produce the proper flow rate for the desired thickness. Since the speed is controlled by controller  302  it will be known (assuming adequate traction and correct mechanical operation of the controller  302 ) and can be fed into G FF     —     carriage , which is a feed forward gain factor. This factor can account for changes in the speed of duct coating applicator  10  determined from the carriage speed setting  306 . The provided duct diameter signal provided back to controller  302  from duct coating applicator  10  scaled by the feed forward factor G FF     —     dia  to account for duct diameter changes as well. 
         [0047]    Through the feed forward mechanisms just described, combined with user inputs, controller  302  controls the pump speed and carriage speed to create the desired thickness T of the applied coating. It will be appreciated that controller  302  must have the correct forward gain factors G FF     —     carriage  and G FF     —     dia . These may be derived based upon computations based on known factors, such as thickness T, nominal pipe diameter, and projected speed of the carriage. However, in some embodiments, it may be faster and more convenient to determine them empirically through testing. The gain factors can then be programmed into, or provided to, controller  302 . 
         [0048]    The controller  302  may be implemented in hardware, software, or a combination. A graphical interface could be designed that allows a user to enter parameters and to start and stop the operation of the duct coating applicator  10 . In other embodiments, a selection of switches and dials may be arranged on a control box. In this case, a user may dial in or select for parameters and modes of operation. The underlying control hardware could be a general purpose microcontroller, an application specific integrated circuit, or various computers on a chip that may also incorporate I/O ports for sending the control signals to the duct coating applicator  10 . 
         [0049]    Thus, the present invention is well adapted to carry out the objectives and attain the ends and advantages mentioned above as well as those inherent therein. While presently preferred embodiments have been described for purposes of this disclosure, numerous changes and modifications will be apparent to those of ordinary skill in the art. Such changes and modifications are encompassed within the spirit of this invention as defined by the claims.

Technology Category: b