Abstract:
A station for reloading a sprayer is disclosed that includes a tank coupled to at least one coating material circuit by a coupler, a docking unit that is adapted to receive a sprayer; and at least one accumulator having a volume that is greater than or equal to the volume of the tank. Each accumulator is connected to at least one circuit by the coupler. The station also includes a mechanism for pressurizing the accumulator. The accumulator is connected to the docking unit which is, in turn, connected to the tank.

Description:
RELATED APPLICATIONS 
     The present application is a §371 U.S. national stage entry of International Application No. PCT/FR2009/052453, filed Dec. 8, 2009, which claims the priority of France patent application No. 08 58415 filed Dec. 9, 2008, all of which are incorporated herein by reference in its entirety. 
     FIELD 
     The present invention relates to a station and to a method for re-supplying a coating material to at least one atomizer equipped with a reservoir and disposed on a robot mounted to move relative to articles to be coated. 
     BACKGROUND 
     EP-A-0 274 322 describes a spraying installation for spraying a coating material onto articles to be coated, such as motor vehicle bodies. The term “coating material” is used to mean any material that is to be sprayed onto an article to be coated, e.g. a primer, a paint, or a varnish, etc. A station is used to re-supply coating material to an atomizer equipped with a reservoir and disposed on a robot mounted to move relative to motor vehicle bodies. That station includes coupling means for coupling to coating material circuits. The coupling means are formed by connector elements, each of which is mounted at the end of a respective coating material circuit. Each coating material circuit makes it possible, when selected, to feed the reservoir equipping the atomizer. 
     The re-supply station described by EP-A-0 274 322 also includes a docking unit defining an atomizer-receiving zone for receiving the atomizer equipped with its reservoir. After a stage of spraying on the articles to be coated, in order to re-supply the atomizer and its reservoir with coating material, the robot comes to place the atomizer in the atomizer-receiving zone. Then the reservoir is connected to the circuit of the coating material that is to be transferred to the reservoir, via corresponding coupling means of the docking unit. After the reservoir has been filled, the robot resumes moving the atomizer facing the articles to be coated. 
     When the coating material is to be changed, e.g. when the shade of paint is to be changed, then, prior to filling, the atomizer and its reservoir must be rinsed with a cleaning material. To that end, the re-supply station described by EP-A-0 274 322 also includes another connector element performing the function of coupling member for coupling to a cleaning material duct. The term “cleaning material” is used to mean any solvent adapted to remove the coating material from the surfaces of the reservoir and of the atomizer. 
     Prior art stations and methods take a relatively long time to change coating materials because the pressure in conventional circuits is generally limited to 6 bars, thereby resulting in a flow rate for filling the reservoir that is limited to 3000 cubic centimeters per minute (cm 3 /min). Thus, re-supply lasts about 20 seconds for a reservoir of 400 cm 3 , including 10 seconds for docking the atomizer and for connecting the reservoir to the docking unit. In an installation for painting motor vehicle bodies, such a re-supply station and such a re-supply method make it possible to coat no more than 50 vehicles per hour. 
     In addition, in order to limit settling-out of a coating material, in particular of a paint, when it stagnates in a circuit of a paint installation as described by WO-A-01 015 814, each coating material circuit must be made up of two distinct paths for causing the coating material to flow regularly. A “go” path brings the coating material from a pump to the coupling means of the station, while a “return” path brings the coating material back from the coupling means to the pump. Unfortunately, the costs of manufacturing, assembling, and maintaining such two-path circuits are relatively high. 
     A particular object of the invention is to remedy those drawbacks by proposing a station that makes fast re-supply possible, that is of simple construction, and that limits wastage and settling-out of the coating materials. 
     SUMMARY 
     To this end, the invention provides a station for re-supplying coating material to at least one atomizer equipped with at least one reservoir and disposed on a robot that is mounted to move relative to the articles to be coated. 
     The station includes:
         coupling means for coupling to at least one coating material circuit; and   a docking unit defining an atomizer-receiving zone for receiving at least one atomizer.       

     The station further includes:
         at least one accumulator having a volume greater than or equal to the volume of the reservoir, the or each accumulator being adapted to be connected to at least one respective coating material circuit via the coupling means;   pressurizing means for putting the volume of the accumulator under pressure;   connection means for connecting the or each accumulator to the docking unit; and   a connection member for connecting the docking unit to the reservoir.       

     According to other advantageous but optional characteristics of the invention, taken in isolation or in any technically feasible combination:
         the station includes a versatile accumulator connected to a plurality of circuits via coupling means that include a coating material change block, the versatile accumulator being connected firstly to the coating material change block and secondly to the docking unit;   the station includes a plurality of accumulators, each of which is connected to a respective circuit via distinct coupling means, the connection member including, for each accumulator, a head valve configured for being connected to the atomizer;   the station further includes at least one coupling member for coupling to at least one cleaning material duct, and the docking unit further includes a device for rinsing the outside surfaces of the atomizer, the device being connected to the cleaning material duct via the coupling member, the device being mounted to move between a plurality of positions corresponding to the respective head valves.   the versatile accumulator is dedicated to the coating materials that are used least often, while each other accumulator is dedicated to a coating material that is used more often;   the or each accumulator operates reversibly, so that it can transfer coating material either towards the docking unit or towards the coupling means for coupling to the corresponding circuit;   the pressurizing means comprise a coupling and a respective thrust chamber belonging to the or to each accumulator, the thrust chamber being designed to be put under pressure in such a manner as to expel coating material from the corresponding accumulator, the coupling being adapted to connect the thrust chamber to a compressed air duct;   the pressurizing means comprise a respective piston belonging to the or each accumulator, the piston defining the thrust chamber and being mounted to move in translation in the corresponding accumulator; and   the station further includes at least one pressure sensor for regulating the pressure prevailing in the or each accumulator and in the connection means.       

     The present invention also provides a method of re-supplying coating material to at least one atomizer equipped with at least one reservoir and disposed on a robot that is mounted to move relative to articles to be coated. 
     The method uses a station including:
         a docking unit defining an atomizer-receiving zone for at least one atomizer;   at least one accumulator having a volume greater than or equal to the volume of the reservoir, the or each accumulator being adapted to be connected to at least one respective coating material circuit via coupling means;   connection means for connecting the or of each accumulator to the docking unit; and   a connection member for connecting the docking unit to the reservoir.       

     The method comprises the following steps:
         a) filling the or each accumulator with coating material via the coupling means;   b) pressurizing the volume of the accumulator;   c) placing the atomizer in the atomizer-receiving zone;   d) connecting the reservoir to the docking unit;   e) transferring the coating material from one of the accumulators to the docking unit so as to fill the reservoir.       

     According to other advantageous but optional characteristics of the invention, taken in isolation or in any technically feasible combination:
         the filling step   e) consists in:   f) isolating the accumulator from the circuit by closing off the coupling means; and in   g) performing the transfer at a transfer flow rate lying in the range 4000 cm 3 /min to 6000 cm 3 /min, the accumulator being put under a transfer pressure greater than the filling pressure prevailing in the circuit, the transfer pressure lying in the range 10 bars to 30 bars, and preferably being equal to 15 bars;   the method further comprises the following steps:   h) prior to the placement step b), positioning a device for cleaning the outside surface of the atomizer at a head valve corresponding to the accumulator serving to perform the transfer step d); and   i) essentially during the coupling step c) and during the transfer step d), rinsing the outside surfaces of the atomizer by means of the device;   the method further comprises the following steps:   j) connecting the accumulator to the respective circuit by opening the coupling means; and   k) returning into the corresponding circuit the coating material contained in an accumulator, after a length of time determined so as to limit settling-out of the coating material.       

     The invention can be well understood and its advantages also appear from the following description, given merely by way of non-limiting example and with reference to the accompanying drawings, in which: 
    
    
     
       FIGURES 
         FIG. 1  is a perspective view of a station of the invention; 
         FIG. 2  is a perspective view from a different angle of the station of  FIG. 1 ; 
         FIG. 3  is a view on a larger scale of detail III in  FIG. 2 ; 
         FIG. 4  is a section view on plane IV of  FIGS. 2 ; and 
         FIG. 5  is a view on a larger scale of detail V in  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a station S including a docking unit  200  that defines an atomizer-receiving zone  250  for receiving an atomizer  1 . The atomizer  1  is carried by a robot  2 , the casing of which is shown in chain-dotted lines. The robot  2  is mounted to move in such a manner as to move the atomizer  1  relative to the articles to be coated, which articles may be vehicle bodies moved by a conveyor, as shown in  FIGS. 1 to 3  of EP-A-0 274 322. 
     The atomizer  1  is equipped with a reservoir  10  that is said to be “internal” because it is incorporated in a body  11  defining the outer casing of the atomizer  1 . When the atomizer  1  is in the atomizer-receiving zone  250 , the station S can re-supply the reservoir  10  with coating material. 
     The docking unit  200  includes a frame  201  and a deck  210  mounted at the top of the frame  201 . The frame  201  and the deck  210  support some of the components of the docking unit  200  and some other components of the station S. 
     The station S also includes five accumulators  110 ,  120 ,  130 ,  140 , and  150  that are stationary relative to the station S. The accumulators  110 ,  120 ,  130 ,  140 , and  150  have identical structures, so that only the structure of the accumulator  120  is described in detail below. The description given below of the accumulator  120  and of its peripheral components can be transposed directly to the accumulators  110 ,  130 ,  140 , and  150 , with the exception of the differences explicitly mentioned on the subject of the accumulator  150 . 
     The accumulators  110 ,  120 ,  130 , and  140  are disposed in the bottom portion of the frame  201 , while the accumulator  150  is mounted close to the deck  210 . Each accumulator  110 ,  120 ,  130 ,  140 , and  150  has a body that is essentially tubular in shape with a circular base. The accumulators  110 ,  120 ,  130  and  140  extend vertically and in juxtaposed manner, while the accumulator  150  extends horizontally. The accumulators  110 ,  120 ,  130 , and  140  thus form a set of accumulators  100 . Each accumulator  110 ,  120 ,  130 ,  140 , or  150  is made of an electrically conductive material, e.g. of metal, and it is grounded, i.e. it is taken to ground potential, by means of conductor wires or of fastening screws (not shown), so as to ensure operator safety. 
     As shown in  FIG. 4 , the tubular body of the accumulator  120  has a volume V 120  that is defined at its two ends by respective end plates  127  and  128 . The accumulator  120  is connected to a circuit  20  that is represented as a chain-dotted line in  FIG. 4 , and that contains a coating material, namely liquid paint of a determined shade of color in this example. The accumulator  120  is connected to the circuit  20  via a coupling  121  to which the end-piece of the circuit  20  is fastened. The coupling  121  forms coupling means for coupling the accumulator  120  to the circuit  20 . 
     In the present patent application, the terms “interconnect”, “connect”, and “couple” refer to fluid communication, i.e. to a link enabling a gaseous or liquid fluid to flow or to circulate between two or more points or parts. Such a link may be direct or indirect, i.e. formed by a duct, by a pipe, or by a channel etc. Similarly, the nouns derived from these verbs, such as “interconnection”, “connection”, and coupling, concern such fluid communication. 
     Like the accumulator  120 , each accumulator  110 ,  120 ,  130 , and  140  is connected to a respective paint circuit, not shown, such as the circuit  20  via respective couplings that are visible in  FIG. 2  but that are not referenced therein. In other words, each accumulator  110 ,  120 ,  130 , or  140  may be dedicated to a paint of a determined shade. 
     The prime function of the circuit  20  is to feed the accumulator  120  with paint. Such a circuit is usually referred to as a “circulating” circuit. The circuit  20  may be formed by a hose, in which case the paint is subjected to a pressure of about 6 bars by a pump (not shown). The circuit  20  belongs to the paint spraying installation in the same way as the station S does. 
     In addition, the accumulator  120  is connected to the docking unit  200  by connection means that comprise a coupling  122 , a pipe  123 , and a coupling  222 . 1 . The coupling  122  is fastened in the end plate  127 . The coupling  222 . 1  is fastened in a base  220  belonging to the docking unit  200 . The pipe  123  extends between the couplings  122  and  222 . 1 . 
     The base  220  is disposed on the deck  210  close to the atomizer-receiving zone  250 . As shown in  FIG. 3 , the base  220  is provided with a plurality of juxtaposed head valves, including the head valves  221 ,  222 ,  223 ,  224 , and  225  that correspond to respective ones of the accumulators  110 ,  120 ,  130 ,  140 , and  150 . Each valve  221 ,  222 ,  223 ,  224 , or  225  has a conventional structure and it is driven by pneumatic members (not shown). Alternatively, each valve  221 ,  222 ,  223 ,  224 , or  225  may be configured to be driven by the atomizer  1 , either mechanically or by means of a pneumatic drive, thereby making it possible to open the respective valve  221 ,  222 ,  223 ,  224 , or  225  only after the atomizer  1  has been connected. 
     As shown in  FIG. 5  the head valve  222  controls the flow of material into an outlet channel  232 , i.e. it allows material to flow into said outlet channel or it prevents material from flowing into said outlet channel. The outlet channel  232  is defined in the base  220  in which it forms the downstream end of the docking unit  200 , and thus of the station S. Each head valve  221 ,  222 ,  223 ,  224 , or  225  forms a connection member for connecting the docking unit to the reservoir  10 . In practice, the head valve  222  or equivalent connects an outlet channel  232  or equivalent of the base  220  to the reservoir  10  via the atomizer  1 . In order to re-supply its reservoir  10 , the atomizer  1  must be connected to an outlet channel  232  or equivalent. The selected outlet channel is the outlet channel that corresponds to the required shade of paint. 
     In the present patent application, the terms “downstream” and “upstream” are used with reference to the direction of flow of the fluid, coating material, compressed air, or cleaning material. 
     Unlike the accumulators  110 ,  120 ,  130 , and  140 , the accumulator  150  is connected to a plurality of circuits  70  to  79  that circulate various different coating materials which, in this example, are paints of various different shades. The paint circuits  70  to  79  are shown in chain-dotted lines in  FIGS. 1 and 2 . The accumulator  150  is connected to the circuits  70  to  79 , in particular via a coating material change block  152 . The block  152  has a conventional structure and conventional functions. 
     As shown in  FIG. 1 , the block  152  is made up of a juxtaposition of a plurality of elementary modules  160  to  169 , with one elementary module  160  to  169  per circuit  70  to  79 . A respective coupling  170  to  179  is connected to each elementary module  160  to  169 . The end-pieces of the paint circuits  70  to  79  are fastened in respective ones of the couplings  170  to  179 . The coupling means for coupling the accumulator  150  to the paint circuits  70  to  79  comprise the block  152  and the couplings  170  to  179 . 
     These coupling means also comprise a coupling  151  fastened in an end plate  157  mounted at one end of the accumulator  150 . The coupling  151  is connected to the block  152  via a pipe  154  that is shown as a chain-dotted line in  FIG. 2 . 
     In addition, as shown in  FIGS. 1 ,  2 , and  4 , the accumulator  150  is connected to the base  220  via connection means that comprise:
         a coupling  156  fastened in the end plate  157 ;   a coupling  225 . 1  fastened in the base  220  and analogous to the coupling  222 . 1 ; and   a pipe  153  that extends between the couplings  156  and  225 . 1 .       

     Since the accumulator  150  is connected to a plurality of paint circuits  70  to  79 , it is said to be “versatile”. In other words, the accumulator  150  is not dedicated to any one specific paint, but rather it is dedicated to a plurality of distinct paints of various different shades of color. The accumulator  150  is dedicated to paints that are used least often, whereas each accumulator  110 ,  120 ,  130 , or  140  is dedicated to a shade of paint that is used more often. In other words, the accumulator  150  is dedicated to “rare” shades, whereas each accumulator  110 ,  120 ,  130 , or  140  is dedicated to a “main” shade. 
     In addition, the docking unit  200  includes a device  251  for rinsing the outside surfaces of the atomizer  1 . The device  251 , which is known per se, is connected to a cleaning material duct (not shown) via a coupling member or coupling  252  that is visible in  FIG. 1 . The atomizer-receiving zone  250  comprises the top rectangular opening in the frame  201 , through which opening a portion of the atomizer  1  can pass so as to penetrate into the device  251 . In addition, the device  251  is connected to a compressed air duct (not shown) in such a manner as to dry the previously injected cleaning material. 
     The device  251  is mounted on a carriage  253  that is mounted to move in translation relative to the frame  201 , as indicated by the doubled-headed arrow X 251 , by means of an actuator (not shown). The device  251  is thus movable between positions corresponding to the body  11  of the atomizer  1  being aligned with each respective head valve  221 ,  222 ,  223 ,  224 , or  225 . In addition, the docking unit  200  includes a jack  215  configured to move the deck  210 , and thus the base  220 , in translation as indicated by the double-headed arrow X 220  in such a manner as to connect the base  220  and the atomizer  1  to each other and to disconnect them from each other. 
     As shown in  FIGS. 2 and 3 , the docking unit  200  further includes a plate  204  that is secured to the docking unit  200 . When the atomizer  1  is connected, the plate  204  is situated facing the distal end of the atomizer  1 . The plate  204  is fastened to the carriage  253 , so that it is also movable in translation relative to the frame  201  as indicated by the double-headed arrow X 251 . The adjective “distal” designates an element of the atomizer  1  that is relatively far away from the robot  2 , while the adjective “proximal” designates an element that is closer thereto. 
     The plate  204  is provided with a through orifice  206 . The plate  204  has a lug  207  on each of its faces so as to guide the atomizer  1  and the base  220  into leaktight contact. The plate  204  serves as a interface between the atomizer  1  and the docking unit  200 , and more precisely between the atomizer and each head valve  221 ,  222 ,  223 ,  224 , or  225 . 
     While the docking unit  200  is being connected to the atomizer  1  and to its reservoir  10 , firstly the actuator  215  moves the deck  210  until the base  220  and the plate  204  come into contact with each other. The plate  204  and the head valve  222  are put into leaktight contact by moving relative to each other, it being possible for this relative movement to be achieved in translation by the robot  2  and/or by the actuator  215 . When one of the lugs  207  has penetrated into a bore corresponding to the head valve  222 , the outlet channel  232  is connected to the orifice  206 . 
     Secondly, the robot  2  places the atomizer  1  close to the plate  204 . A valve  12  is incorporated into the atomizer  1  in order to control re-supplying the reservoir  10 . The plate  204  and the distal portion  13  of the valve  12  are put into leaktight contact by relative movement that can be achieved in translation by the robot  2  and/or by the actuator  215 . 
     Each accumulator  120  or equivalent includes a piston  120 . 2  and a thrust chamber  120 . 1 . The piston  120 . 2  is mounted to move in translation inside the accumulator  120 . The thrust chamber  120 . 1  is defined by the piston  120 . 2  and by the walls of the accumulator  120 . The paint is contained in the chamber, referenced V 120 , that is defined by the piston  120 . 2  and that is situated above the thrust chamber  120 . 1 . In a variant, the thrust chamber  120 . 1  may be placed above the chamber containing the paint. The thrust chamber  120 . 1  is designed to be put under pressure so as to exercise a thrust force F 120  on the piston  120 . 2 , in such a manner as to expel the paint from the accumulator  120 . 
     In order to increase the pressure in the thrust chamber  120 . 1 , a thrust fluid, which is compressed air in this example, is delivered via the air duct  25 . The air duct  25  is connected to the end plate  127  via a coupling  125 , and then to the end plate  128  via a duct and via a coupling that are not shown. The thrust fluid flows from the duct  25  into the coupling  125 , and then into the end plate  127 , before being injected into the thrust chamber  120 . 1 , via the duct and the coupling that are not shown. Alternatively, a coupling of type  125  may be mounted directly on the end plate  128 . 
     A pneumatic distributor valve (not shown), such as a three-port valve, controls intake of compressed air into the thrust chamber  120 . 1 , via the air duct  25 . This pneumatic distributor valve also controls discharge of compressed air from the thrust chamber  120 . 1 , preferably to the atmosphere, so as to reduce the thrust force F 120  to zero, thereby making it possible to fill the accumulator  120  with paint. 
     Each accumulator  110 ,  120 ,  130 ,  140 , or  150  operates reversibly, i.e. it can transfer paint either towards the docking unit  200  via the pipe  123  and via the coupling  122 , or towards the circuit  20  via the coupling  121 . The direction of the paint delivered by the accumulator  120  is selected by means of a selector valve  129 . 1  received in the end plate  127 . The selector valve  129 . 1  can close off the couplings  121  and  122  in alternation and simultaneously. The selector valve  129 . 1  thus controls intake of paint into the accumulator  120  from the paint circuit  20 , and discharge of paint from the accumulator  120  towards the pipe  123 . 
     The pipes  123  and  153  that connect the base  220  to respective ones of the accumulators  110 ,  120 ,  130 ,  140 , and  150  have relatively short lengths, thereby making it possible to minimize the head losses in the flow of the paint, and thus to limit the length of time necessary for re-supplying the reservoir  10  via the accumulator  120  or equivalent. 
     The station S operates using a re-supplying method of the invention. This method includes a step consisting in filling one or more accumulators  110 ,  120 ,  130 ,  140 , and  150 , as a function of the shades of paint selected for the next paint spraying cycles, this step being performed in masked time. For example, the accumulator  120  is filled with the paint that is contained in the circuit  20 . The expression in “masked time” means that the step is performed as a background task concurrently with a paint spraying cycle, i.e. without slowing down the throughput rate of the painting installation. 
     In order to perform this filling, the pneumatic distributor valve is caused to go into discharge mode, so as to establish, inside the accumulator  120 , a pressure that is less than the pressure prevailing in the duct  20 . The thrust force F 120  is zero and the paint can enter the accumulator  120  by pushing back the piston  120 . 2 . In this state, the pressure in the accumulator  120  is the same as the pressure in the circuit  20 , namely typically 6 bars. 
     Then, the selector valve  129 . 1  is caused to “open” the coupling  121 , so that paint flows from the duct  20  into the accumulator  120 . Since the piston  120 . 2  does not resist intake of the paint into the accumulator  120 , the accumulator  120  can be filled in masked time, during the paint spraying stage performed by the atomizer  1 . When coating a vehicle body, the spraying stage lasts about 1 minute. 
     In order to fill the volume V 10  of the reservoir  10  completely, the volume V 120  of the accumulator  120  or equivalent must be greater than or equal to the volume V 10 . For example, for a volume to be filled V 10  of 400 cm 3  it is possible to use an accumulator  120  having a volume V 120  of 600 cm 3 , or indeed of 1000 cm 3 . 
     After the accumulator  120  has been filled, the coupling  121  is “closed”, by controlling the selector valve  129 . 1  in such a manner as to interrupt the fluid communication between the circuit  20  and the accumulator  120  or equivalent. The accumulator  120  is then isolated from the circuit  20 . 
     Then the means for putting the volume V 120  under pressure are actuated: a pneumatic distributor valve feeds the thrust chamber  120 . 1  via the coupling  125  so as to increase the pressure prevailing in the accumulator  120  to a pressure significantly higher than the pressure of the circuit  20 . When the thrust chamber  120 . 1  of the accumulator  120  is at a pressure of about 15 bars, the accumulator  120  is ready to deliver the paint it contains towards the docking unit  200  for the purpose of re-supplying the reservoir  10 . 
     Thus, the coupling  125  and the thrust chamber  120 . 1  form means for putting the volume V 120  of the accumulator  120  or equivalent under pressure, to a pressure (15 bars) strictly greater than the pressure that prevails in the circuit  20  (6 bars). 
     At the end of a paint spraying cycle, after the step of filling the accumulator  120  or equivalent, the atomizer  1  is connected to the base  220 , by moving the robot  2  and the deck  210  towards the plate  204 . More precisely, the atomizer  1  and the base  220  are moved closer together until the plate  204  comes into contact on one side with the front portion  13  of the valve  12  and on the other side with the valve head  222 . 
     The volume V 10  is brought to a pressure that is relatively low or zero, e.g. to atmospheric pressure. Then, the coupling  122  is “opened” so as to deliver paint into the pipe  123  and to the reservoir  10  via the docking unit  200 . 
     When the reservoir  10  is filled, the atomizer  1  and the base  220  are disconnected and the robot disengages the atomizer  1  from the atomizer-receiving zone  250 . The atomizer  1  thus leaves the station S so as to reach the paint spraying space. 
     At the end of a paint spraying cycle, the reservoir  10  equipping the atomizer  1  is partially or fully empty. It is then necessary to re-supply the reservoir  10  with paint, by filling it as described above. To this end, the robot  2  places the atomizer  1  in the atomizer-receiving zone  250 . Prior to this, the device  251  is positioned at the head valve  222  corresponding to the accumulator  120  or equivalent that serves to transfer paint as a function of the selected shade. When the atomizer  1  is in the device  251 , any paint residue is dumped from the reservoir  10 . Said paint residue is collected by the device  251  and is then conveyed to a waste treatment center (not shown). 
     When the shade of paint is to be changed, the inside of the reservoir  10  is rinsed by means of a solvent duct (not shown) that can be connected to the plate  204 . As is known per se, the device  251  uses solvent brought via the coupling  252  to clean the outside surfaces of the portion of the atomizer  1  that carries the atomizer member and that can thus have been soiled. 
     As described above, once the thrust chamber  120 . 1  has been put under pressure, and thus once the paint contained in the volume V 120  of the accumulator  120  has been put under pressure, the head valve  222  and the coupling  121  are “opened” via the selector valve  129 . 1 , so that the paint flows from the accumulator  120  into the reservoir  10  via the pipe  123 , thereby transferring the paint from the accumulator  120  towards the docking unit  200 , and towards the reservoir  10 . 
     The flow rate of this transfer from the volume V 120  to the volume V 10  depends on the pressure prevailing in the volume V 120  or equivalent. When the volume V 120  is put under 15 bars of pressure via the coupling  125 , the flow rate of filling of the volume V 10  can reach 6000 cm 3 /min throughout the stage of re-supplying the reservoir  10 . 
     Such a filling flow rate makes it possible to fill a volume V 10  of 400 cm 3  in less than 5 seconds. This filling time, plus the time necessary for docking the atomizer  1 , makes it possible to limit the total re-supply time necessary for re-supplying the atomizer  1  to less than 12 seconds. The “total re-supply time” means the length of time between stopping and resuming spraying paint onto the articles to be coated. 
     A station and a method of the present invention thus make it possible to achieve re-supply in a significantly shorter time than prior art stations and methods. The time necessary for changing shades is thus also shortened. Therefore, a station and a method of the present invention make it possible to achieve a spraying throughput rate of about 60 to 70 vehicles per hour. 
     In practice, the transfer pressure may lie in the range 10 bars to 30 bars, and the transfer flow rate may lie in the range 4000 cm 3 /min to 6000 cm 3 /min. In the present application, the pressures that are mentioned are pressures that are relative and static. 
     In order to regulate this pressure of 15 bars prevailing in the accumulator  120  or equivalent, and in the connection means such as the pipe  123  or  153 , the station S also has at least one pressure sensor  208 , shown diagrammatically in  FIG. 5 . 
     In a painting installation, the shade of paint to be sprayed onto each motor vehicle body is selected by a supervision unit. This supervision unit defines a wide variety of shade sequences, so that it is possible for a shade not to be selected for a relatively long time, during which the paint stagnates in one or more accumulators  110 ,  120 ,  130 ,  140 , or  150 . 
     In order to limit settling-out of said stagnant paint, a method of the invention further includes a step during which the paint stagnating in the accumulator  110 ,  120 ,  130 ,  140 , or  150  is returned into the respective paint circuit after a length of time that is determined as a function of the characteristics of the paint. 
     In order to return paint in this way, the accumulator  120  or equivalent is connected to the circuit  20  by opening the coupling  121  by means of the selector valve  129 . 1 . Since the volume V 120  is at a pressure, typically 15 bars, that is higher than the pressure, typically 6 bars, prevailing in the circuit  20 , the paint flows from the accumulator  120  back into the circuit  20 , until the volume V 120  has been fully emptied. This return thus limits stagnation of paint in the accumulator  120  or equivalent. Subsequently, it is possible to fill the accumulator  120  again, in the steps described above, so as to respond to a command from the supervision unit. 
     In a variant (not shown), instead of returning the paint via the coupling  121 , a station of the invention may, for each accumulator, have a specific return coupling and a specific return duct, feeding of these specific elements being controlled by valves. 
     In addition, a station of the invention may, for each accumulator, have a “drain” circuit and a “drain” valve in order to collect the solvent that has flowed through the accumulator during the cleaning stage. 
     This reversible operation of the accumulators limits paint settling-out. Thus, a re-supply station of the invention may be connected to coating material circuits, each of which is made up of a single path for the “go” and “return” flows of the coating material. Nevertheless, a re-supply station of the invention may be connected to coating material circuits having two paths, namely a “go” path and a “return” path, that generally exist in a conventional painting installation. 
     In addition, a re-supply station of the invention does not need coating material circuits of greater dimensions because they are brought to usual pressures, of about 6 bars. 
     The structure of the station and the structure of the installation of which it is part are thus simpler than those of the prior art, thereby significantly reducing manufacturing, assembly, and maintenance costs. 
     In addition, in spite of the shade sequences that can be complex, a station and a method of the present invention improve the management of paints of different shades because the “rare” shades are handled by the versatile accumulator, and the “main” shades are handled by dedicated accumulators. This improved management of the various shades of paint also makes it possible to reduce wastage of coating material and of cleaning material. 
     The station S is shown with five dedicated accumulators. However, a re-supply station of the invention may have as many dedicated accumulators as there are “main” shades. For example, a re-supply station of the invention may have in the range one dedicated accumulator to thirty dedicated accumulators, and preferably sixteen accumulators. 
     In a variant (not shown), the means for putting the volume of each accumulator under pressure comprise a thrust chamber formed directly above the coating material. Such an accumulator is not provided with any piston and the compressed air then exerts its pressure directly on the coating material that it expels from the accumulator. Each accumulator then operates like a pot under pressure.