Patent Publication Number: US-8978578-B2

Title: Powder delivery apparatus

Description:
CROSS REFERENCE TO CO-PENDING APPLICATION 
     The present application claims priority benefit to the Oct. 27, 2011 filing date of provisional patent application, Ser. No. 61/552,146 for POWDER DELIVERY APPARATUS filed in the name of Alexander I. Jittu, the contents of which are incorporated herein in its entirety. 
    
    
     BACKGROUND 
     The present invention relates, in general, to powder paint delivery apparatus and methods. 
     Paint coatings are typically applied to large objects, such as automotive vehicle bodies, automotive vehicle parts and other objects in a closed paint booth. The automotive bodies or parts to be painted move through the booth in a sequential manner, typically via conveyor. 
     Paint applicators are disbursed throughout the booth and, are frequently in the form of programmed robotic applicators. 
     Although liquid spray paint has been frequently employed in the past, current technology is moving to powder paint coating application. In a typical powder paint application, powder from a bag or tote is supplied to at least one virgin powder hopper. A percentage of the output of the virgin hopper is supplied to one or more mix hoppers which also receive reclaimed overspray powder paint from the paint booth in a selected ratio. 
     The powder paint is transported from the virgin and mix hoppers through a network of multi-directional valves to the paint applicators. A control system controls the position of the multi-directional valves so as to enable 100% virgin powder paint to be supplied to one or more specific paint applicators in the paint booth, and/or 100% mixed powder paint from the one or more mix hoppers to one or more specific paint applicators in the paint booth. 
     If additional mix hoppers are employed, the ratio of reclaimed powder paint to virgin paint in such mix hoppers can be different from the primary or other mix hopper so that a different mix of virgin and reclaimed powder paint can be supplied to specific applicators in the paint booth. 
     In dense phase powder paint systems using positive air pressure to transport the powder from the hoppers to the paint applicators, applicator pumps generally have a pump chamber including a gas permeable member. Powder paint is supplied to the chamber along with a fluidizing gas, such as air. The fluidized dense phase powder is then discharged from the pump chamber to a paint applicator for disbursal over the object being painted. 
     Since paint booths typically employ a large number of separate paint applicators, the complexity of the valve and pump networks used to transport powder paint from virgin and mix hoppers to the individual paint applicators can be complex. This complexity necessarily results in frequent breakdown due to the number of components, the viscosity of the powder being transported through the transport systems which can lead to frequent clogging, etc. Production must be halted to repair any damaged or inoperative component in the powder paint transport system. 
     It would desirable to provide a powder paint delivery apparatus which addresses these deficiencies. 
     SUMMARY 
     An apparatus for paint powder transportation between a first location and an application point includes a first powder hopper with a plurality of individual outlets, a first pair of transfer pumps, one pump coupled to each of the plurality of individual hopper outlets for transferring powder from the hopper in separate powder flow paths, two final dense phase pumps for transferring powder to two application location powder applicators, and a first cross feed network is formed of a plurality of multi-directional valves including a first pair of inlet valves, each coupled to one of the first pair of transfer pumps, and a pair of outlet valves, each coupled to one of the two final dense phase pumps. Each inlet valve has two outlets, each outlet coupled to one inlet of both outlet valves, whereby control of the inlet and outlet valves allows powder to be transferred from the hopper by either of the first and second transfer pumps through the cross feed network to either of the two final feed dense phase pumps. 
     In another aspect, a second pair of transfer pumps are provided with each second pump coupled to one of a plurality of individual first hopper outlets. The second pair of transfer pump is coupled to one of the multi-directional inlet valves of the cross feed network. 
     In another aspect, the apparatus further include, a second pair of final feed dense phase pumps at the application location which are coupled to individual powder applicators. Separate outlets of the cross-feed network are coupled to multi-directional valves in turn coupled to each of the second pair of final feed dense phase pumps such that control of the multi-directional valve selects one of each of the second pair of final feed dense phase pumps to deliver powder to one applicator. 
     In one aspect, the first powder hopper is a virgin powder hopper. 
     In another aspect, the first powder hopper is a mix hopper containing virgin powder and reclaimed powder. 
     In one aspect, the apparatus further includes a second powder hopper, another first pair of transfer pumps coupled to one of a plurality of individual second hopper outlets for transferring powder from the second hopper in separate powder flow paths, and a separate pair of final feed dense phase pumps. A second cross feed network is formed of a plurality of multi-directional valves including a first pair of inlet valves, each coupled to one of the another first pair of transfer pumps, a pair of outlet valves, each coupled to one of the another two final feed dense phase pumps. Each inlet valve has two outlets, each outlet coupled to one inlet of both outlet valves, whereby control of the inlet and outlet valves allows powder to be transferred from the second hopper to either of the first and second pairs of transfer pumps through the first and second cross feed networks to either of the final dense phase pumps. 
     The apparatus in the latter aspect includes a first group of powder applicators; a second group of powder applicators; and a plurality of multi-directional valves coupled between the outlets of the first and second cross feed networks and the first and second groups of powder applicators to provide powder from each of the first and second hoppers to at least one applicator in each of the first and second groups of applicators 
     In the latter aspect, the first hopper contains virgin powder; and the second hopper contains a mixture of virgin powder and reclaimed powder. 
     In the latter aspect, each of the first and second groups of applicators includes at least three separate applicators. 
     In this apparatus, multi-directional valves are coupled to the outlet of the outlet valves of each of the first and second cross feed networks and each of the three separate applicators in one of the first and second groups of applicators. 
     In one aspect, the apparatus includes each separate applicator having at least one final feed dense phase pump. 
     In another aspect, the apparatus further comprises at least one separate applicator including a pair of applicators. Multi-directional valves are coupled to each pair of the pair of applicators to selectively control the transport of powder to either pump of the pair of pumps. 
     In one aspect, the apparatus includes a third powder hopper, and a third pair of transfer pumps, each coupled to one of a plurality of individual third hopper outlets for transferring powder from the third hopper in separate flow paths. A third pair of transfer pumps has each pump coupled to one of a plurality of individual third hopper outlets. The third pair of transfer pumps are coupled to one of the multi-directional inlet valves of a third cross feed network. 
     In one aspect, the apparatus includes a plurality of powder hoppers, a plurality of transfer pumps coupled to each of a plurality of hopper outlets for transferring powder from each hopper in separate flow paths, separate cross-feed powder flow networks fluidically coupled to the outlets of each hopper, each separate cross feed network having a plurality of outlets, and valves coupled to the outlets of each of the plurality of cross feed network outlets for selectively delivering powder from each outlet of each of the plurality of hoppers to each of the plurality of application points. 
     In another aspect, a liquid paint overspray collection apparatus includes a collection tray located in a paint booth to collect paint overspray which did not adhere to an article being painted in the paint booth. A layer of lime is replaceably disposed in the collection tray for coagulating contact with the paint overspray, and means for discharging lime particles coated with paint overspray from the collection tray to a collection hopper. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The various features, advantages and other uses of the present powder delivery apparatus and method will become more apparent by referring to the following detailed description and drawing in which: 
         FIG. 1  is a schematic diagram of one aspect of a powder delivery apparatus; 
         FIG. 2  is a schematic diagram of one aspect of the transport network used to transport powder from the hopper shown in  FIG. 1  to paint applicator; 
         FIG. 3  is a schematic diagram of another aspect of one aspect of the transport network used to transport powder from the hopper shown in  FIG. 1  to paint applicator; 
         FIGS. 4 and 5  are cross-sectional views of different multi-directional valve employed in the powder transport network shown in  FIGS. 2 and 3 ; 
         FIG. 6  is a schematic diagram of one aspect of a final feed dense phase delivery pump arrangement; 
         FIG. 7  is a schematic diagram of another aspect of a final feed dense phase delivery pump configuration; 
         FIG. 8  is a partially cross-sectioned view of a final feed dense phase delivery pump which may be employed for any of the pumps shown in  FIGS. 6 and 7 ; 
         FIG. 9  is a partially cross-sectioned view of another aspect of a final feed dense phase delivery pump which may be employed for any of the pumps shown in  FIGS. 6 and 7 ; 
         FIG. 10  is a pictorial representation of a typical automotive body paint booth with a reclaim powder collection system and pump apparatus; 
         FIG. 11  is an exploded pictorial view of the supply of reclaim powder from the powder reclaim collectors shown in  FIG. 10  to a reclaim hopper; 
         FIG. 12   a  is a schematic and partially cross-sectioned diagram of a micro powder delivery apparatus; 
         FIG. 12   b  is a partially cross-sectioned view showing a construction of the micro powder material hopper shown in  FIG. 12   a;    
         FIG. 13  is a schematic diagram showing the connections to the final feed dense phase pump shown in  FIG. 12   a;    
         FIG. 14  is a schematic diagram of liquid paint spray apparatus using particulate lime collection trays for paint overspray collection; 
         FIG. 15  is a schematic diagram of another aspect of the powder delivery apparatus; 
         FIG. 16  is a schematic diagram of yet another aspect of the powder deliver apparatus; and 
         FIG. 17  is a schematic diagram of another aspect of a powder delivery apparatus. 
     
    
    
     DETAILED DESCRIPTION 
     An apparatus and, more particularly, a powder paint delivery apparatus, uses a positive pressure, airflow powder pump  40  to transfer powder, such as paint powder, from a bulk powder supply bag or tote  30  to a virgin hopper  32  containing pure virgin powder. 
     Since paint booths typically employ a large number of separate paint applicators, the complexity of the valve and pump network. 
     A reclaim powder hopper  34  collects reclaim powder from a paint delivery booth or area, as described hereafter. A positive pressure pump  42  transfers reclaimed powder from the reclaim hopper  34  through a two way multi-directional valve  44  to at least one and, for example only, two mixer hoppers  36  and  38 , hereafter referred to as mix  1  hopper  36  and mix  2  hopper  38 . The mix  1  and mix  2  hoppers  36  and  38  serve as temporary storage for reclaimed powder and virgin powder, which is transferred through a two-way multidirectional valve  46  by a positive pressure pump  48  from the virgin hopper  36  to either mix  1  or mix  2  hopper  36  and  38 . 
     As shown in the powder paint deliver booth depicted in  FIG. 10 , powder paint is delivered to opposite sides of the booth for application to opposite sides of an article, such as a vehicle body. The powder paint delivery devices on either side of the paint booth are referred to generally as left side automation and right side automation. 
     As shown in  FIG. 2 , a plurality of positive pressure air flow powder pumps  50  are connected to individual, separate outlets of the virgin hopper  32 . By way of example, four pumps  50  are connected to individual outlets of the virgin hopper  32 . Each pump  50  can be paired with another pump  50  to form two positive pressure powder flow paths from the virgin hopper  32 . The outlets of each pair of pumps  50  are coupled through a two-way multi-directional valve  52  to a reverse oriented two-way multi-directional valve  54 . A second pair of pumps  50  are coupled to the inlets of a two way multi-directional valve  56 . The outlet of the valve  56  is coupled to the inlet of a two-way multi-directional valve  58 . 
     The multi-directional valves  54  and  58  form a pair of inlet valves of a cross feed network  51  which also includes a pair of outlet valves  60  and  62  and cross feed fluid connections or conduits extending between the two outlets on each of the inlet valves  54  and  58  and the two inlets of each of the outlet valves  60  and  62 . 
     One flow path extends directly from one outlet of the valve  54  to one inlet of the valve  60 . A second flow path  66  is coupled between the second outlet of the valve  54  and one inlet of valve  62 . 
     Similarly, a flow path  68  extends directly between one outlet of the valve  58  and one inlet of the valve  62 . A cross feed flow path  70  is formed between the other outlet of the valve  58  and the second inlet of the valve  60 . The outlet of the valve  60  is coupled to the inlet of a three way multi-directional valve  72 . Similarly, the outlet of valve  62  is coupled to the inlet of another three-way multi-directional valve  74 . 
     As shown in  FIG. 1  and described above, the mix  1  and  2  hoppers  36  and  38  have an inlet from the two-way valve  44  to receive reclaimed powder from the reclaim hopper  34  via pump  42 . Another inlet to the mix  1  and  2  hoppers  36  and  38  receives virgin powder from the virgin hopper  32  via two-way valve  46  and pump  48 . This enables the output of the virgin hopper  32 , as described above and shown in  FIG. 2 , to selectively be 100% virgin powder only or a mixture of virgin powder and reclaimed powder, such as a mixture of 90% virgin powder and 10% reclaimed and virgin powder from the mix  1  and  2  hoppers  36  and  38 . 
     Each mix  1  and  2  hopper  36  and  38 , as shown in  FIG. 2 , has outlets for supplying reclaimed powder from the reclaim hopper  34  mixed with virgin powder from the virgin hopper  32  directly to the paint area. The virgin hopper  32 , as also shown in  FIG. 2 , has additional outlets for directly supplying 100% virgin powder directly to the paint area, without any mixing with reclaimed powder. 
     Since the following pumps and valves have the same arrangement and serve the same function as the pumps and valves  50 - 74  shown in  FIG. 2  for the virgin hopper  32 , like parts are given like reference numbers. Thus, at least one pair, and, for example, a plurality of pairs of positive pressure transfer pumps  50  are coupled to individual outlets of the mix  1  hopper  36 . The pumps  50  are arranged in pairs, with each pair of pumps  50  connected to separate outlets of the mix  1  hopper  36 . Each associated pair of pumps  50  is coupled to an inlet of a two-way multidirectional valve  52  or  56 . The valves  52  and  56  are coupled to two-way inlet valves  54  and  58  and form part of a cross-fee network  53  along with a cross feed fluid flow connections or fluid passageways  64 ,  66 ,  68  and  70 . The cross feed fluid flow network feeds outlet valves  60  and  62  which are coupled with fluid communication with three-way multi-directional valves  80  and  82 , respectively. 
     Another pair of pumps  50  are coupled to individual outlets of the mix  1  hopper  36 . Each pump of this pair of pumps  50  is coupled to two-way valves  57  and  59 . The two outlets of the valve  59  are coupled through positive pressure pumps  61  to individual powder delivery guns or nozzles, labeled “sill guns  61 ” by way of example only in  FIG. 2 . 
     Similar arrangement of separate outlet flow paths and a cross feed network is provided from the mix  2  hopper  38  and three-way valves  84  and  86 . 
     A plurality of three-way valves, with six three-way valves  90 ,  92 ,  94 ,  96 ,  98 , and  100  are arranged to receive selected outputs from the three-way valves  72 ,  74 ,  80 ,  82 ,  84  and  86  to supply powder to the left side and right side automation powder delivery devices or paint guns in one example. 
     The three-way valves  90 ,  92 ,  94 ,  96 , phase,  98  and  100  allow multiple flow paths for powder to be delivered through a plurality of final feed dense phase delivery pumps, all denoted by reference number  102 , from selected ones of the outlets of the virgin hopper  32  and the mix  1  and mix  2  hoppers  36  and  38 . 
     Thus, the three outlets of three-way valve  72 , which receive powder from the virgin hopper  32 , are connected to three-way valves  96 ,  98 , and  100  to feed the selected output devices on the right side automation. The opposed three-way valve  74  is coupled to receive powder from the virgin hopper  32  and feeds individual valves  90 ,  92 , and  94 . 
     Similarly, the right side three-way valve  80  is coupled to receive powder from the mix  1  hopper  36  and has three outlets respectively coupled to the three-way valves  96 ,  98  and  100 . The right side three-way valve  84  coupled to the mix  2  hopper  38  likewise has three outlets respectively coupled to the valves  96 ,  98 , and  100 . Similarly, for the left side automation, valves  74  coupled to the virgin hopper  32  has three outlets individually, respectively coupled to the valves  90 ,  92 , and  94 . The left side valve  82  coupled to the mix  1  hopper  36  has  3  outlets respectively coupled to individual inlets on the valves  90 ,  92 , and  94 . Similarly, the left side valve  86  coupled to the mix  2  hopper  38  has three outlets respectively coupled to the valves  90 ,  92 , and  94 . 
     By way of example, the three-way valves  90  and  96  are directly coupled to separate two-way valves  104 . The two-way valves  104  are coupled to two final feed dense phase delivery pumps  102 . 
     The single outlet of each three-way valve  92  and  98  is coupled through an individual two-way valve  106 . The two outlets of the two-way valves  106  are coupled to individual two-way valves  108  and  110 , each of which is coupled to two pairs of final feed dense phase delivery pumps  102 . 
     Similarly, the three-way valves  94  and  100  have a single outlet coupled to an inlet of individual two-way valves  112 . The two outlets of the valve  112  are coupled to inlets of additional two-way valves  114  and  116 , each of which is fluidically coupled to a pair of final feed dense phase pumps  102 . 
     The above-described powder flow arrangement allows any mixture of virgin powder, mix  1  hopper powder or mix  2  hopper  38  powder to be supplied through the final feed dense phase delivery pumps  102  to the powder applicator devices in the paint booth. A portion of the powder in the mix hoppers  36  and  38  also can be supplied to sill guns via sill gun transfer pumps  61 . 
     Thus, for example, virgin powder from the virgin hopper  32  may be independently supplied to each of the left side automation and right side automation powder applicator devices. The virgin powder may also be mixed with reclaim powder in either or both of the mix  1  hoppers  36  and  38  for transfer by the final feed dense phase delivery pumps  102  to the application points. 
     Reclaim powder in the mix  1  hopper  36  may also be supplied independently of powder in the mix  2  hopper  38  virgin powder from the virgin powder hopper  32  to the application points via the final feed dense phase delivery pumps  102 . Similarly, reclaim powder in the mix  2  hopper  38  may be supplied exclusively to the applicant points via the final feed dense phase delivery  102  without mixing with any powder from the mix  1  hopper  36  or the virgin hopper  32 . 
     The use of a pair of pumps coupled to individual outlets of each of the virgin hopper  32 , the mix  1  hopper  36  and the mix  2  hopper  38  allows multiple powder supply paths from the hoppers  32 ,  36  and  38 . This enables a continuous transfer of powder from the hoppers  32 ,  36 , and  38  even if one of the outlets is clogged and inoperative or if one of the transfer pumps  50  breaks down or is otherwise inoperative. 
     The cross feed network formed of valves  54 ,  58   60  and  64  and the cross feed flows path  64 ,  66 ,  68  and  70  allow powder from multiple transfer pumps  50  associated with each hopper  32 ,  36  and  38  to be supplied to either the left side or right side automation. This allows powder to be supplied continuously to the application points despite any breakdown in a single flow path or one of the pumps or valves in any flow path. 
     Previously, powder in such applications was delivered exclusively to the left side automation or the right side automation. A breakdown of the powder transfer apparatus on one side of the article being painted could lead to a total shut down of the production line since powder could only be supplied to one side of the article and not simultaneously to both sides. The cross feed network allows powder, in any mixture of virgin and reclaimed powder, to be supplied simultaneously to both of the left side and right side automation powder delivery paths and selectivity between flow paths to overcome any break down of equipment. 
       FIG. 3  depicts a powder delivery apparatus which is substantially identical to the apparatus described above and shown in  FIG. 2 . The only difference between the powder delivery apparatus shown in  FIGS. 2 and 3  is that the apparatus shown in  FIG. 3  has only a single final feed dense phase delivery pump  102  coupled to each discharge two-way valve  104 , rather than the separate pairs of final feed dense phase delivery pumps  102  shown in  FIG. 2 . 
     Referring now to  FIG. 15 , there is depicted another example of a powder delivery apparatus based on the principles of the powder delivery apparatus shown in  FIGS. 2 and 3  and described above. A hopper  500  can function as a hopper for either virgin powder, or as a mix hopper for a predetermined percentage of virgin and reclaimed powder. Two pumps  502  and  504  attached to separate discharge outlets of the hopper  500  and individually supply powder from the hopper  500  to separate inputs in the cross feed network formed of valves  54 ,  58 ,  60  and  64  and cross connected fluid connections as described above and shown in  FIGS. 2 and 3 . 
     The single outputs from the valves  60  and  62  are coupled through a multi-directional valve  506  and  508 , respectively, to individual single final feed dense phase pumps  510  and  512 , respectively. It will be understood that the use of the multi-position or direction valves  506  and  508  is optional. 
       FIG. 16  depicts a similar example of a powder delivery apparatus. In this aspect, powder supplied to the hopper  540  may again be virgin powder or a mixture of virgin and reclaimed powder. Further, in this aspect, pairs of delivery pumps  542  and  544  are connected to separate discharge outlets in the hopper  540 . The outlets of the pumps  542  are supplied to separate inputs of a multi-directional valve  546 , the output of which is coupled to the input of inlet valve  54  of a cross feed network. 
     The outputs of the other pair of pumps  544  are connected to the inputs of a multi-positional valve  548 . The single output of the valve  548  is coupled to the input of valve  58  of the cross feed network formed of valves  54 ,  58 ,  60  and  64  and fluid conduits. 
     The output of the cross feed network, namely, the separate outputs of valves  60  and  64 , are respectively supplied to multi-direction valves  550  and  552 . The separate outputs from each valve  550  and  552  are coupled to inputs of two multi-direction valves, such as valves  554  and  556  for the valve  550 , and valves  558  and  560  for the valve  552 . 
     The output or outputs of each valve  554 ,  556 ,  558  and  560  may supply powder to at least one final feed dense phase pump  562  or a pair of final feed dense phase pumps, including additional pumps  564 . 
     In this latter aspect, inoperability, breakdown or clogging of any one line in the powder transport network between the hopper  540  and any of the pumps  562  and  564  may be overcome by switching any of the valves  546 ,  548 ,  550 ,  552 ,  554 ,  556 ,  558  and  560  as well the individual valves  54 ,  58 ,  60  and  64  in a cross feed network to alter the route that powder from the hopper  540  is delivered to a particular pump  562  or  564 . 
       FIG. 17  depicts another aspect of a powder delivery apparatus which is similar to the apparatus depicted in  FIG. 3 , but only includes two hoppers. One of the hoppers, such as hopper  600 , may be supplied with virgin powder. The other hopper  602  may be supplied with a mixture of reclaim powder and virgin powder. 
     As the pump and valve networks used to transport powder from the hopper  600  and  602  to a plurality groups of pumps, respectively denoted by reference numbers  604  and  606 , as the same as that depicted in  FIG. 3 , the description of the powder delivery network shown in  FIG. 3  and described above will be understood to apply equally to the powder delivery network shown in  FIG. 17 . 
     The details of one example of a two-way multi-directional valve, such as two-way valve  54 , is shown in  FIG. 4 . The two-way multidirectional valve  54  includes a body with separate conduit connections including first, second and third connections  120 ,  122 , and  124 . The fluid connections allow a conduit representatively shown by reference number  126  to be fluidically coupled to the body  118  of the valve  54 . 
     The two-way valve  54  is multidirectional in that the conduit  126  may serve as a single inlet or a singlet outlet for the valve  54 . Likewise, the pairs of conduits  126  coupled to connections  122  and  124  may serve as a pair of outlets or a pair of inlets depending upon how the valve  54  is coupled in the powder flow path. The conduits  126  coupled to the valve body  118  via the connections  122  and  124  have bores  128  and  130 , respectively, which merge within the interior of the valve body  118  into a single bore  132  leading through the conduit connection  120 . 
     An example of a three-way multi directional valve, such as valve  72 , is shown in  FIG. 5 . The three-way valve  72  has a construction similar to the two-way valve  54  in that a first connection  140  allows a first conduit  142  to be coupled to the body  144  of the valve  72 . Three separate connections  146 ,  148  and  150  allow connection of individual conduits  152 ,  154 , and  156 , respectively, to the valve body  144 . Each conduit  152 ,  154 , and  156  is respectively disposed in fluid flow communication with an interior bore  160 ,  162 , and  164 . The bores  160 ,  162 , and  164  merge into a single bore  166  leading to the single connection  140 . 
     In both of the two-way and three-way valves  54  and  72 , for example, pneumatically actuated pinch valves, not shown, are mounted in each inlet and outlet coupling to control the flow of powder through the valve. The pinch valves are controlled by external pneumatic circuitry to enable each valve to direct fluid flow in the desired flow path through the valves  54  and  72 . 
       FIG. 6  depicts one pair of final feed dense phase deliver pumps  102 , hereafter referred to separately by reference numbers  102 A and  102 B, coupled to a single two-way valve  116 , as shown in  FIG. 2 . 
     Each final feed dense phase delivery pump  102 A and  102 B is similarly constructed of a hollow body  180 . The body  180  rests on a scale  182 . A fluidization inlet port  184  is provided for supplying air to the powder within the body  180  to fluidize the powder for consistent volume delivery. A powder support port  186  is coupled to the valve  116  and the body  180  to supply powder to the pump  102 A. A vent port  188  with a restriction or pinch valve is provided on the body  180  to prevent pressure build up within the body  180 . 
     A delivery valve  190  is coupled within a discharge path  192  leading from the pump body  180  to one or more such as two powder delivery applicators  194 . 
     It should be noted that the other final feed dense phase delivery pump  102 B is identically constructed and has its discharge path  192  coupled in common with a discharge path  192  from the opposite pump  102 A. This allows powder to be supplied from either pump  102 A or  102 B to the powder applicator(s)  194 . 
     For example, the final feed dense phase delivery pump  102 A can be active and supplying powder to the applicators  194 ; while the opposite final feed dense phase delivery pump  102 B is inactive or being refilled with powder. Similarly, pump  102 B can be active and supplying powder to the applicators  194 ; while the other pump  102 A is inactive or being refilled with powder. 
       FIG. 7  depicts an example of a single final feed dense phase delivery pump  102  for the single final feed pump aspect of the powder delivery apparatus shown in  FIG. 3 . As the pump  102  shown in  FIG. 7  is identically constructed as the pumps  102 A and  102 B, the description of the construction and operation of the pump  102 A will be understood to apply equally to the pump  102  shown in  FIG. 7 . The single pump  102  shown in  FIG. 7  can be refilled during down time in the production line, between production shifts, between paint application operations, or between two adjacent cars running on the production line. 
     The use of one or more applicators supplied by a single pump allows dispersion as well as a back up capability in case of clogging or failure of one of the applicators  194 . 
     Referring now to  FIG. 8 , there is depicted one example of the structure of a final feed dense phase delivery pump  200 , which can be employed in any of the pumps  102 . The pump  200  has a closed body  202  with a cleaning gas port  204 , a powder supply port  206  and a vent port  208  which may be located on the upper end of the body  202 . A restriction valve, such as a pinch valve  210 , is contained within the body  202  for converting the turbulent flow of the powder delivered through the powder inlet  206  to laminar flow into the interior of the pump body  202 . A pressure control  212  is coupled to the body  202  for controlling the pressure of the air within the body  202 . A fluidization plate  214  is mounted within the lower portion of the interior of body. The air or gas within the body  202  fluidizes the powder above the plate  214 . 
     A powder pickup tube or conduit  216  is disposed at an angle within the body  202  and extends from above the fluidization plate  216  to an outlet connection on a side portion of the body  202 . A vent port  220  is also coupled to the connection  219 . The connection  219  provides fluid communication between the powder pickup  216  within the body  202  and an external powder supply conduit  222  which extends from the connection  219  to a trigger valve  224 . Dilution air is supplied through a fitting  226  to dilute the powder as it exits an applicator  228 . 
     A fluidization port  215  opens below the fluidization plate  214  to provide fluidization air or gas to the powder within the body  202 . 
       FIG. 9  depicts a modification of the final feed pump shown in  FIG. 8 . In this aspect of the final feed dense phase delivery pump, the powder supply port  206  is still located on the upper end of the pump body  202 . However, in this aspect, a first restrictive valve or pinch valve  229  is located in the upper portion or neck of the pump body  202 . The neck of the pump body  202  expands from the narrow upper end into an enlarged chamber  231 , which is formed between the first restrictive or pinch valve  229  and a second restrictive or pinch valve  233 . The vent port  204  and the cleaning port  208  are coupled in fluid communication with the enlarged chamber  231 . 
     The purpose of the two pinch valves  229  and  231  in this aspect of the final feed pump is to control powder delivery to the body  202  by gradually opening the tightly closed first pinch valve  229 . This translates turbulent flow of the powder delivered through the powder inlet port  206  to laminate flow through the second pinch valve  233  as the second pinch valve  233  is opened to allow the powder to flow to the interior of the pump body  202 . 
       FIG. 10  depicts a typical powder paint application in which a closed area, such as a closed paint booth  230 , contains multiple robotic devices  232  and/or automatic machines, and/or manual paintwork stations which carry powder applicators  234  for dispensing powder paint onto an article being painted, such as vehicle body  236 . 
     Excess powder that does not adhere to the vehicle body  236  falls through openings in the booth floor  238 . Powder collector chambers  240  are located below the booth floor  238 . Multiple powder collector chambers  240  may be situated side-by-side along each side of the length of the booth  230 . Filters  242  located in a lower portion of the powder collector chambers filter debris from the powder and allow the powder to flow through a pump  244 . The pump  244  may be used for any of the pumps  40 ,  42 ,  50 , etc., described above. The outlets of the left side and right side automation collector pumps  244  are coupled through a two-way multi-directional valve  246  to transfer the reclaimed powder to a powder reclaim collector via conduit  248 . 
     A level sensor, not shown, or a scale can be employed to detect the powder level or quantity of powder within each powder collection chamber  240 . Once a predetermined powder level is detected within either powder collector  240 , control circuitry activates movement of the filters  242  in a back pulse manner to allow the powder to flow from the powder collector  240  by the pump  244  to the collection hopper. 
     It should be noted that the pair of left and right side pumps  244 , the two way valve  246 , and the conduit  248  are repeated for each pair of left side and right side powder collectors along the length of the booth  230 , as well as any manual paint applicator zones or work stations, and a silenced zone as shown in  FIG. 11 . 
     The powder reclaim collector  250  is mounted above the reclaim powder hopper  34  and receives the conduits  248  from each pair of reclaim powder collector pumps  244  and two-way valves  246 . The collected powder passes through a powder seive  252  before flowing into the interior of the reclaim hopper  34 . 
       FIG. 12A  is a schematic diagram depicting a micro-powder delivery apparatus. In this apparatus, micro powder material  250  is supplied to one or more bulk powder tanks  252 . A dense phase powder pump  254  transfers micro-powder from the bulk tanks  252  to a seive  256 . A powder conduit tube  258  is coupled between the seive  256  and a micro-powder material hopper  260 . 
     The hopper  260  supplies micro sized powder material through a pump  262  to a final feed pump  264  which can be constructed according to either of the final feed pumps  200  shown in  FIG. 8  or  9 . The final feed pump  264  supplies powder to one or more powder applicators  266 . 
     An example of the construction of the hopper  260  is shown in  FIG. 12B . An electric motor  272  drives an agitator  274  within the interior of the pump body  276 . A fluidization plate  278  is located above the bottom of the hopper  260  and below the agitator  274 . The hopper  260  may rest on a scale  280 . 
     An example of the connections to the final feed dense phase pump  264  depicted in  FIG. 12A  is shown in  FIG. 13 . A vent port  290  with a restriction or pinch valve  292  is coupled to an upper end of the pump body  294 . A powder supply port  296  is also provided on the upper end of the body  294 . A pressure control device  296  is coupled to the interior of the body  294  to control air pressure within the pump body  294 . A fluidization port  298  is coupled to a lower portion of the pump body  294  to provide a fluidization air or gas to the powder through a fluidization plate  300  located in bottom portion of pump body  294 . A powder delivery tube or conduit  302  exits the body  294  through a delivery valve or trigger  304 . A delivery tube  306  extends from the trigger  304  to one or more powder delivery applicators  308 . Each applicator  308 , as shown from one of the applicator&#39;s  308  can include a recovery valve  310 , a multicolor dilution port  312  and the powder delivery applicator itself  314 . 
     Referring now to  FIG. 14 , there is depicted another aspect of the present invention which applies selected features described in the previous various powder delivery apparatus to a liquid paint spray system using a particular material that coagulates with the liquid paint particles, such as lime or domolit, as a paint overspray collection medium. 
     In a liquid paint spray application, such as the application of liquid spray paint in a spray booth  400  by one or more applicators, such as one more left side applicators and one or more right side applicators, overspray or liquid paint which does not adhere to the vehicle body  402  falls onto collector tray, such as a left side collector  404  and an identical right side collector  406  which are located on or below the paint booth  400  floor adjacent to the opposite lower sides of the vehicle body  402 . 
     The liquid paint droplets fall onto the lime or domolit supplied to the collection trays  404  and  406  and coagulate and/or are captured by the solid lime or domolit particles. The coagulated particles of lime and liquid paint fall into chambers  408  and  410 . Filters  412  and  414  are mounted in the lower portions of the chambers  408  and  410 , respectively. The filters  412 ,  414  are back pulsed or vibrated to separate the dry lime particles from the coagulated paint lime droplets. The coagulated paint and lime particles are drawn off for disposal. 
     Transfer pumps  416  and  418  draw the paint lime particles from the filters  412  and  414 , respectively. Pipes connected to the pumps  416  and  418  are merged in a two-way multi-directional valve  420 . The output of the valve  420  is connected to a collection hopper  422 . 
     As shown in  FIG. 14 , virgin lime is supplied to a bulk unload hopper  430 . Virgin lime is transferred from the bulk onload hopper  430  by a transfer pump  432  to a delivery hopper  440 . At least two transfer pumps  442  and  444  are connected to separate outlets of the hopper  440  to disperse virgin lime to the left side and right side collection trays  404  and  406 . 
     A lime discharge drive  450  and  452  is associated with each collection tray  404  and  406 , respectively. The drives  450  and  452  are movable along the longitudinal length of each collection tray  404  and  406 , respectively, to disburse fresh lime particles from the conduits coupled to the transfer pumps  442  and  444 . 
     The coagulated lime and paint particles are drawn forcibly through the filters  412  and  414  by a pressurized air stream. When a drop in air pressure is detected, the filters  412  and  414  are vibrated or back pulsed to allow the coagulated lime and paint particles to flow through the filters  412  and  414  and be drawn into the collection hopper  422 .