Abstract:
A rotary pump plural component applicator apparatus is provided for dispensing plural components, such as resins and adhesives or the like, with an activator for the resins or adhesives. A plural component applicator uses an electric motor gear box driving first and second rotary pumps. The use of an electric motor driving plural rotary pumps improves the plural component applicator performance in the application of the plural components.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/848,851, filed Oct. 3, 2006. 
         [0002]    The present invention relates to a plural component applicator in which multiple chemicals are metered prior to dispensing of the mixture and to an electrically operated rotary pump proportioning and dispensing system which may be operated in the field while maintaining precision ratios of liquid components under different physical conditions. 
         [0003]    Multiple component delivery pumps are used when two or more materials have to be combined to obtain a desired product prior to dispensing the mixture. The process generally has to ensure that the ratio between the components is maintained accurately and continuously. This is true, for example, when components of plastic materials are delivered which cure by chemical reaction. Multiple component dispensing systems for dispensing resins, adhesives, acrylic materials, urethanes and the like are well known and currently marketed by various manufacturers. 
         [0004]    These prior systems operate satisfactory but have several operational disadvantages as a result of being operated pneumatically through plural piston-type pumps. Typically, a multi-component dispensing system has an air operated drive motor operatively connected to a pair of metering piston pumps which serves to dispense materials, such as adhesive materials, or resins and an associated activator. These prior metering pumps typically are air driven or gear driven by means of a drive gear mounted to a drive motor. The drive motor in turn drives a pair of piston pumps which pump the liquid materials from mixing prior to dispensing. 
         [0005]    The concept of using a pair of piston pumps which are mechanically connected and operated by one power source for delivery of multi-components from separate tanks is well known. The operation of a piston pump produces slight variations in the mixture due to the cycling of the piston in the pumps. A reciprocating pump must change direction at the end of every stroke, similar to an engine; the piston reaches top dead center and is reversed. Each time a piston pump changes direction, the balls must re-set and send fluid in the opposite direction, showing gauge bounce or dip. If gauges could read fast enough, you would see pressure go to zero at top and bottom of each stroke if not for hose expansion, check valve and fluid reservoirs. Various techniques have been used to minimize this effect including using larger hoses, pumps and the like. 
         [0006]    The present invention advantageously utilizes plural rotary pumps driven by a single power source for simultaneously applying metered amounts of liquids from separate tanks into a mixing nozzle where they are mixed and dispensed. Rotary pumps which are electrically driven are used in dispensing of the liquids. 
         [0007]    Prior plural component application machines have generally been unable to maintain an exact ratio of two materials desired at a controlled temperature to achieve a uniform mix of materials at the spray nozzle. Most prior plural applicator machines use compressed air motors to drive a pair of piston pumps, one for each material. This results in a lead-lag in the material flow when the pistons pump stop and change direction since the pumps do not lead-lag at the same time thereby varying the ratio of material during a cross-over of the pistons sometimes causing clogging or stoppage of flow to materials. The materials are reactive when mixed together even for an instant which can cause a reaction, clogging or stopping the machine. 
       SUMMARY OF THE INVENTION 
       [0008]    A rotary pump plural component applicator is provided for dispensing plural components, such as resins and adhesives or the like, along with an activator for the resins and adhesives. The plural component applicator has an electric motor having a drive shaft connected to a gear box to drive first and second rotary pumps, each pump having an input and an output. A first storage tank is connected to the first rotary pump input while a second storage tank connects to a second rotary pump input. A first heater is coupled to the first rotary pump output for heating a liquid from the pump output while the second heater is coupled to the second rotary pump output for heating a liquid from the second rotary pump output. The first dispensing valve is connected to the first heater and to an applicator nozzle while a second dispensing valve is connected to the second heater for dispensing the heated liquid to the applicator nozzle. Thus, an electric motor driven rotary pump plural component applicator improves the ratio of the mixed components and of the application of the components. A first three-way valve is connected between the storage tank in the first rotary pump for directing a liquid from the first storage tank or from an auxiliary storage tank to the first rotary pump input. A second three-way valve is connected between the second storage tank and the second rotary pump for directing liquid from the second storage tank or from an auxiliary storage tank to the second rotary pump input. The rotary pump plural component applicator is mounted on a wheeled cart having an electric motor and gear box mounted generally vertical on the cart with each rotary pump mounted to one side of the gear box. An electric motor control is mounted on the wheeled cart. A first dispensing valve has a manifold having a feedback line to the first tank while the second dispensing valve has a manifold having a feedback line of the heated liquid to the second tank. An activation control allows the simultaneous activation of both first and second dispensing valves for dispensing liquids to an applicator nozzle. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Other objects, features, and advantages of the present invention will be apparent from the written description and the drawings in which: 
           [0010]      FIG. 1  is a flow diagram of the plural material portion of the system; 
           [0011]      FIG. 2  is an exploded perspective of an electric motor, gear box and rotary pumps; 
           [0012]      FIG. 3  is a perspective view of the plural component applicator in accordance with the present invention; 
           [0013]      FIG. 4  is a front elevation of the plural component applicator of  FIG. 3 ; 
           [0014]      FIG. 5  is a partially exploded perspective of the plural component applicator of  FIGS. 3 and 4 ; 
           [0015]      FIG. 6  is a partial perspective of a second embodiment of the plural component applicator having the motor and one pump removed; and 
           [0016]      FIG. 7  is a partial perspective view showing the three way diverter valve of the plural component applicator. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0017]    Referring to the drawings and especially to  FIG. 1 , a flow chart is illustrated by the operation of the pumping system in which the electric motor  12  is shown connected to gear box  14  which in turn is connected to the rotary pump  20  on one side and  22  on the other side. A tank  24  is connected through a three-way diverter valve  25  to the rotary pump  22  while a tank  26  for holding a separate liquid material to be pumped is connected through a three-way diverter valve  27  to the rotary pump  20 . The rotary pump  22  is connected through a heater  28  while the rotary pump  20  is connected to a heater  30 . After the liquid in the tank  24  is pumped through the heater  28 , it passes through an output  31  to the spray gun passing through a valve  32 , which valve controls the output  31  to the application device, such as a spray gun, injection nozzle or pouring. Simultaneously, a recirculation line  33  recirculates the heated material back to the tank  24 . Similarly, the liquid being pumped from the tank  26  through the heater  30  is directed into a dispensing valve  34  and from there through the output  35 ,to the application device where the outputs  31  and  35  are mixed in the application device prior to dispensing. A feedback line  36  is also connected through the dispensing valve  34  to allow the recirculation of the heated liquid from the tank lead back to the tank  26 . The valves  32  and  34  are controlled simultaneously by an activation handle  37  for dispensing the liquids from tank  24  and  26  simultaneously to the spray gun. 
         [0018]    Referring to  FIG. 2 , an electric motor  10  is connected through couplings  11  to a motor output housing  12  which is connected by an adaptor plate  13  to a gear box  14  having an output shaft  15  and  16  from each side of the gear box  14 . The output shaft  15  is connected through a coupling  17  through a lubrication housing  18  to the pump  20 . Similarly, an output shaft  16  is connected through a second lubrication housing  21  to a second rotary pump  22  so that the pumps  20  and  22  are driven simultaneously by the electric motor  10  through the gear housing  14 . 
         [0019]    Referring to  FIGS. 3 ,  4  and  5 , a plural component applicator  40  is illustrated. The applicator  40  is mounted in a cart  41  having a plurality of wheels  42  for rolling the applicator  40  into position. Cart  40  also has a handle  43  for grasping and rolling the cart  41 . The electric motor  10  is mounted in the cart and is attached to the housing  12 . The electric motor output shaft is coupled to the gear box  14 . Gear box  14  output shafts are coupled through the lubrication housings  18  and  21  to the rotary pumps  20  on one side  22  on the other side. A rolling cart  41  has a face plate  44  and a cord hook  45  on one side thereof. The tanks  24  and  26  are mounted to the rear of the cart  41 . Adaptor plate  13  can be seen connecting the drive housing  12  to the gear box  14 . Each pump  20  and  22  is connected through a check valve  45  through a tube  46  into a manifold  47  having a pressure gauge  48  mounted thereon. Manifold  47  in turn is connected through a tube  50  into an adapter  51  for connecting a hose and application device to the left side of the plural component applicator  40 . The return tube  33  is also connected between the manifold  47  and the tank  24  while the manifold activation handle  37  can be connected to both manifolds  32  and  34 . The rotary pump  22  and the rotary pump  20  are each connected through a line  52  to their respective tanks  24  and  26  into a three-way diverter valve and through a pressure switch used to start and stop the machine. A speed controller  56  is mounted to the backplate  44 . 
         [0020]    In  FIG. 6 , the electric motor  10  has been removed from the cart and a more detailed control box  57  has been added to provide additional controls including an electric motor speed control  58  for controlling the speed of the DC motor  10 . In  FIG. 6 , the heater  30  is also incorporated into the housing with the heater  28  being removed. 
         [0021]    Referring to  FIG. 7 , a partial perspective view of a corner of the plural component applicator is illustrated showing one corner of the rolling cart  41  having a wheel  42  and illustrating the diverter valve  25  having a handle  60  for changing the input from the tank  24  to a capped output  61 . The diverter valve allows for the connection to a larger remote tank or source of one of the plural components. A matching diverter valve is, of course, located on the other side of the cart below the tank  26 . Thus, a larger source of components can be connected directly to the applicator for handling larger applications of mixed liquids or for a permanent installation. 
         [0022]    It should be clear at this time that a plural component applicator has been provided which distinguishes from prior applicators by utilizing DC electric motors for driving a performance closed loop rotary pumps which allow for the dispenser controls to be turned on or off and which has a full recirculation of each component of liquid back into the tank. The present applicator also advantageously has a three-way diverter valve allowing pumping from larger drums, pails or tanks or for permanent installation and also has various heat settings, ratios and outputs available. However, the present invention is not to be construed as limited to the forms shown which are to be considered illustrative rather than restrictive.