Rotary sprayer for coating product and method for controlling the surface temperature of such a sprayer

Abstract

Rotary Coating Product Sprayer and Method for Controlling the Surface Temperature of Such a Sprayer. This rotary coating product sprayer comprises a spray bowl rotating about an axis of rotation (X2) and an air turbine (12) for driving the bowl. This turbine includes a rotor (14) and a body (16) forming a support for the rotor and defining at least one air supply duct (120-132) for a component (12, 56) of the sprayer. This air supply duct (120-132) for the component (12, 56) of the sprayer includes an intermediate chamber (132) defined radially to the axis of rotation (X2) between the body (16) and a ring (32, 90) mounted around this body. This limits the temperature drop of a sprayer housing element due to the circulation of exhaust air from the turbine (12). Figure for the abstract: 2

Description

Title of the invention: Rotary sprayer for coating product and method for controlling the surface temperature of such a sprayer

[0001] The present invention relates to a rotary coating product sprayer intended in particular for use in applying coating product to a surface to be coated. The invention also relates to a method for controlling the surface temperature of such a sprayer.

[0002] A rotary sprayer is, for example, used to apply a coating such as paint or varnish to a motor vehicle body, a motor vehicle component or a household appliance casing.

[0003] Such a sprayer includes a bowl driven in rotation around an axis of rotation by means of a turbine which may be an air turbine, that is to say a turbine which includes a rotor whose rotation results from the flow of an air stream which impacts fins attached to the rotor.

[0004] This type of sprayer generally performs satisfactorily. However, a problem arises due to the expansion of the drive air, which must be brought to the vicinity of the blades at a relatively high pressure, on the order of 6 bar, and which is at a pressure close to atmospheric pressure at the turbine outlet. This expansion of the drive air, which becomes exhaust air after impacting the rotor blades, has the effect of cooling it significantly, with a temperature difference of approximately 20°C.

[0005] Thus, considering that the air enters the turbine at a temperature of 20 to 25 degrees Celsius (°C) and a relative humidity between 55% and 65%, the temperature of the exhaust air exiting the turbine may be below the dew point, which is between 10 and 18°C. This has the effect of condensing the humidity in the air, to the point that water droplets may accumulate on the outside of the sprayer, even if the turbine body is covered by a hood. These water droplets are likely to detach from the sprayer during spraying and may fall by gravity, or be carried by an aerodynamic phenomenon, onto the surface being coated. This then creates a defect in the applied coating layer.

[0006] In practice, this is not acceptable and it is known to attempt to regulate the drive airflow of an air turbine to limit the risks of water condensation due to the exhaust air temperature.

[0007] For example, EP-A-2 808 089 teaches that a portion of the supply air from an air bearing should be directed into a volume where a vacuum could occur. This This approach has the effect of increasing the overall air consumption of the sprayer, which requires additional resources for the production of pressurized air and increases the operating cost of a coatings installation equipped with such a sprayer.

[0008] It is also known to insert an electric air heater on the air supply line of a sprayer in order to raise the drive air temperature to around 40°C, such that the exhaust air at the turbine outlet will not reach a temperature that could induce condensation of the moisture present in the air. This approach is particularly energy-intensive and requires the purchase of expensive additional equipment.

[0009] The invention aims to solve these problems by proposing a new rotary coating product sprayer with which the risk of water condensation on the surface of the sprayer is greatly reduced, or even completely eliminated, without significantly reducing the energy performance of the sprayer.

[0010] To this end, the invention relates to a rotary coating product sprayer comprising a spray bowl rotating about an axis of rotation and an air turbine for driving the bowl rotating about this axis. This turbine comprises a rotor and a body forming a support for this rotor and defining at least one air supply duct for a component of the sprayer. According to the invention, the air supply duct for the sprayer component comprises an intermediate chamber defined radially to the axis of rotation between the turbine body and a ring mounted around this body.

[0011] Thanks to the invention, the intermediate chamber of the feed duct, which is defined between the body and the ring mounted around it, constitutes a zone of relatively warm air circulation in the outermost part of the body, thus preventing a marked drop in the temperature of the body's periphery in this area. This has the effect of limiting the risk of condensation in this area of ​​the sprayer. The air circulating in this intermediate chamber can then be used to drive the rotating rotor, or to power a component other than the turbine. By another component of the turbine, one might mean a conical paint flow shaping element, also called an "air skirt," or a sound sensor configured to measure the rotor's rotational speed.Using a feed airflow to a turbine element reduces the device's energy consumption compared to a solution using an airflow dedicated solely to limiting cooling, or a heating device for the incoming flow.

[0012] According to advantageous but not mandatory aspects of the invention, such a sprayer may incorporate one or more of the following features taken in any technically permissible combination:

[0013] - The supply conduit which includes the intermediate chamber is the conduit which The turbine's rotating chamber is supplied with drive air. Therefore, the air circulating in the intermediate chamber does not need to be supplied to the sprayer in addition to the air used for normal sprayer operation. Furthermore, as the turbine speeds up, the exhaust air cools, but as the supply air flow rate increases, the thermal effect of the air circulating in the intermediate chamber becomes greater. In other words, the cooling of the turbine's exhaust air and the compensation for this cooling achieved by the ring mounted around the sprayer body both vary in the same direction as the turbine's rotational speed. Moreover, since pressure losses are related to the pressure and flow rate of the supply air, the energy expenditure due to these pressure losses is a function of the energy required to rotate the sprayer bowl.

[0014] - The sprayer is equipped with a component defining circulation channels The air conforming to a cloud of droplets leaving the edge of the spray bowl is supplied by the duct containing the intermediate chamber, which feeds these channels with skirt air. Therefore, in this case as well, the air circulating in the intermediate chamber must not be supplied to the sprayer in addition to the air used for the sprayer's normal operation.

[0015] - The sprayer is equipped with at least one cavity, integral with the rotor, and a A noise-measuring microphone detects the airflow from the cavity to determine the rotational speed of the spray bowl. The duct, which includes an intermediate chamber, supplies the microphone with air through the cavity. Again, the air circulating in the intermediate chamber must not be supplied to the sprayer in addition to the air used for its normal operation.

[0016] - The body includes a tubular part which defines a housing for receiving the rotor and a base which seals the housing opposite the bowl and the ring is mounted around both the tubular part and the base.

[0017] - The ring is provided, on its internal radial surface, with at least one relief, including ribs or a net, configured to promote heat exchange between, on the one hand, the air circulating in the intermediate chamber and, on the other hand, the ring.

[0018] - The ring is made of metal.

[0019] - The sprayer includes an electrical potential balancing subset between the ring and the body, this sub-assembly being provided in particular in the form of an electrically conductive elastically deformable member bearing, directly or via an added electrically conductive element, against the ring and against the body.

[0020] - The ring is immobilized around the body by wedging.

[0021] - At least one sealing gasket, preferably two sealing gaskets, is or are interposed between the body and the ring and contribute to the ring being wedged around the body.

[0022] - The intermediate chamber is provided around a part of the body in which An exhaust gas collector for the turbine is provided.

[0023] - The sprayer is equipped with a temperature sensor to determine the air temperature in the intermediate chamber, ring temperature or sprayer hood temperature.

[0024] In another aspect, the invention relates to a method for controlling the surface temperature of a rotary coating product sprayer comprising a spray bowl rotating about an axis of rotation and an air turbine for driving the bowl rotating about the axis of rotation, this turbine comprising a rotor and a body forming a support for the rotor, this method comprising a step of supplying air to a component of the sprayer. According to the invention, the supply step includes a substep of diverting a supply airflow from the component to a peripheral area of ​​the body to limit a drop in the temperature of a sprayer housing element.

[0025] Advantageously, a sprayer control unit is configured to adjust the operating parameters of the sprayer, or of a cabin in which the sprayer is installed, according to the output signal of the temperature sensor.

[0026] The invention will be better understood and other advantages thereof will become more apparent in the light of the following description of an embodiment of a sprayer according to its principle and of a method for controlling its surface temperature, given solely by way of example and with reference to the accompanying drawings in which:

[0027] [Fig-1] [Fig. 1] is an axial section of a rotary sprayer according to the invention mounted on the wrist of a manipulator robot;

[0028] [Fig.2] The figure is an axial section of a turbine belonging to the sprayer shown in [Fig.1];

[0029] [Fig.3] The [Fig.3] is a larger scale view of detail III in the [Fig.2];

[0030] [Fig.4] Fig.4 is an axial section of the turbine of Figures 2 and 3 taken from a plane offset around an axis of rotation relative to that of figures 2 and 3;

[0031] [Fig.5] The [Fig.5] is an exploded perspective view of the turbine of figures 2 to 4;

[0032] [Fig. 6] [Fig. 6] is a perspective view of the turbine in Figures 2 to 5, along arrow VI in [Fig. 2], in which a base is omitted for clarity of the drawing; and

[0033] [Fig.7] Fig.7 is a perspective section of the turbine in Figures 2 to 6, the base being shown separately from the rest of the turbine and viewed from a different angle.

[0034] The electrostatic sprayer 2 shown in [Fig. 1] is mounted on the wrist 4 of a multi-axis robot 6 shown schematically. The wrist 4 defines an interface zone 8 through which flow supply lines (not shown) for the sprayer 2 supplying fluids, including turbine drive air, skirt air and liquid coating product, as well as power cables for high-voltage components.

[0035] The sprayer 2 includes a bowl 10 intended to be rotated around an axis of rotation X2 defined by a body 2A of the sprayer 2. The bowl 10 is driven in rotation around the axis X2 by an air turbine 12 which includes a rotor 14 movable in rotation around the axis X2 and to which the bowl 10 is attached, as well as a body 16 which forms a support for the rotor 14.

[0036] The body 2A comprises a main part 20 on which the turbine 12 is attached and which is supported against the interface area 8 and an auxiliary body 22.

[0037] The turbine 12, which is one of the components of the sprayer 2, is shown alone in figures 2 and following.

[0038] The rotor 14 and the body 16 are hollow and together define a volume V18 which forms a receiving housing for a coating product injector 18 which allows a flow of liquid coating product to be brought as close as possible to the bowl 10, to be sprayed by means of the bowl 10.

[0039] Here, advantageously, the injector is aligned on the X2 axis.

[0040] The rotor 14 is equipped with fins 142 which are formed on an annular and axial surface 143 of a ring 144 mounted around a hub 146. The number, distribution and geometry of the fins depend on the design choice of the rotor 14, and on the rotational speed intended for the bowl 10.

[0041] Alternatively, other structures are conceivable for the rotor 14. For example, parts 144 and 146 can be monobloc or the blades can be provided on a peripheral surface of the rotor 14.

[0042] The body 16 comprises a tubular part 162 and a base 164, centered respectively on a longitudinal axis XI62 and XI64. In the assembled configuration of the body 16, the axes XI62 and XI64 coincide and define a central axis X16 of the body 16. In the mounted configuration of the sprayer 2, the axes X2 and X16 coincide.

[0043] The tubular portion 162 defines a receiving volume V16 for the rotor 14, which is inserted into this receiving volume from below in Figures 2 and 4, while the base 164 allows this volume to be closed downwards in these figures. The volume V16 is centered on the axis XI6.

[0044] Two air bearings (not shown) are formed on either side of the ring 144, along the axis X2. When supplied with air, they allow the rotor 14 to be positioned relative to the body 16, within the volume V16 and along the axis X2. The air bearings allow the rotor 14 to rotate without contact within the body 16. The air bearings contribute to centering the rotor 14 along the axis X2 and can be described as axial air bearings.

[0045] On the other hand, a radial air bearing is formed around the rotor 14, in the volume V16 and inside the tubular part 162. The radial air bearing allows the rotor 14 to be centered around the axis X16, inside the body 16.

[0046] The bearings of the turbine 12 can, alternatively, be rolling bearings.

[0047] In the assembled configuration of the turbine shown in figures 1 to 4 and 6, the blades 142 are arranged in a rotation chamber 26 formed between portions 162 and 164 of the body 16, in a part left free by the rotor 14.

[0048] The base 164 is fixed to the tubular part 162 by means of several screws 167 which pass through the base from one side to the other, parallel to the axis X164, and are received in corresponding threads of the tubular part 162.

[0049] Screws 28 pass through bores 282 and 284 provided respectively through the tubular part 162 and through the base 164 and allow the turbine 12 to be immobilized against the main part 20.

[0050] The tubular portion 162 has a stepped external shape. More specifically, portion 162 has a circular cross-section about axis XI62 and comprises a front portion 162A, located on the side of the bowl 10 when the bowl is in place, i.e., towards the front of the sprayer, and which has a first external diameter D162A. Part 162 also comprises a rear portion 162B opposite the bowl 10 when it is mounted, i.e., located towards the rear of the sprayer, and which has a second external diameter D162B strictly larger than the first diameter D162A. The base 164 also has a circular cross-section about axis XI64 and has an external diameter DI64 identical to the diameter D162B. Thus, portions 162B and 164 constitute the portion of the body 16 with the largest diameter.

[0051] Alternatively, parts 162 and / or 164 do not have circular external cross-sections. In this case, the tubular part is stepped such that the largest external dimension of the front portion 162A, transverse to the axis XI62, is strictly smaller than the largest external dimension of the rear portion 162A, transverse to axis XI62. Parts 162B and 164 also constitute the portion of the body with the largest transverse dimension relative to axis XI6.

[0052] The front portion 162A is surrounded by the auxiliary body 22, which supports adjacent components and in which circulation channels (not shown) are provided. This auxiliary body 22 is sometimes referred to as the "inner skirt." It is made of a thermally insulating material, such as a plastic, so that it insulates the front portion 162A from a cowling 90 that covers the turbine housing 16 and the auxiliary body 22.

[0053] Keying pins 30 allow the turbine 12 to be oriented around the axis X2 relative to the main part 20, at the rear, and relative to the inner skirt 22, at the front.

[0054] The rotation chamber 26 is supplied with drive air for rotation of the rotor 14 through two conduits 120 and 122, themselves supplied with air by conduits 80 and 82 provided in the main part 20.

[0055] The conduit 120 is straight, in the example parallel to the axis X16 and connected directly to a groove 124 in a spiral portion centered on the axis X16. The conduit 120 is formed in the base 164, while the groove 124 is formed in the tubular part 162. The flow of the drive air in the body 16, along this first path, is represented by the arrows El in Figures 2 and 6.

[0056] The conduit 122 is connected to a second groove 126, also in a spiral portion centered on the axis XI6, which opens into the chamber 26 and which is provided in the tubular part 162.

[0057] Here, the grooves 124 and 126 are provided in the part 162 symmetrically with respect to the axis XI62.

[0058] In practice, in this example, the grooves 124 and 126 are provided in a face of the portion 162B turned towards the base 164 and extend perpendicularly to the axes XI62 and XI6, therefore to the axis X2 in the mounted configuration of the sprayer 2.

[0059] The conduit 122 is straight, in the example parallel to the axis X2, and connected to an elbow 128 which opens onto the peripheral surface S164 of the base 164, opposite a ring 32 which surrounds both parts 162B and 164 of the body 16.

[0060] On the other hand, an elbow 130 is provided in the annular part 162 and opens onto the external peripheral surface S162 of the portion 162B.

[0061] The surfaces S162 and S164 are flush and have the same diameter, D162B or DI64, which corresponds to the fact that the ring 32 has the same diameter over its length L32 parallel to the axis X2.

[0062] If, alternatively, the diameters D162B and DI64 are different, the ring 32 can be stepped.

[0063] Opposite its outlet on the surface S162, the elbow 130 is connected to the spiral groove 126.

[0064] Along a radial direction to the axis X2, between the surfaces S162 and S164, on the one hand, and an internal radial surface 322 of the ring 32, an annular chamber 132 is formed which constitutes a portion of the supply duct to the chamber 26 for drive air, this supply duct being made up of the volumes 122, 128, 132, 130 and 126 into which the drive air flows, as represented by the flow arrows E2 in figures 2, 3 and 6. The chamber 132 is intermediate between the inlet of the supply duct, which is constituted by the mouth of the conduit 122, and the outlet of this duct, which is constituted by the outlet of the conduit 136 into the rotation chamber 26.

[0065] The elbows 128 and 130 allow the drive air flow E2 to be diverted in radial directions to the axis XI6, therefore to the axis X2 in the mounted configuration of the sprayer 2, relative to the pipes 122 and 126. This allows the drive air to circulate in a peripheral area 168 of the body 16 which is radially further from the axis X16 than the pipes 120 and 122.

[0066] The internal radial surface 322 of the ring 32 is provided with ribs 36 which create as many baffles in the chamber 132, which has the effect of increasing the contact area between the air circulating between the bends 128 and 130 in the chamber 132 and the ring 32. Thus, the ribs 36 are configured to promote heat exchange between the drive air circulating in the chamber 132 and the ring 32.

[0067] L32 denotes the axial length of the ring 32, that is to say the length of the ring measured parallel to the axis XI6.

[0068] L162 is also noted as the axial length, measured parallel to the axis XI62, of the portion 162B of the tubular part 162 and L164 as the axial length, measured parallel to the axis XI64, of the base 164.

[0069] In the example, the length L32 is equal to the sum of the lengths L162 and L164. In practice, the ratio L32 / (L162+L164) is chosen to be greater than 0.8, preferably greater than 0.95. In other words, the ring 32 surrounds the widest part of the body 16 over most of its length measured parallel to the axis of rotation.

[0070] Alternatively, the ratio L32 / (L162+L164) may be strictly greater than 1.

[0071] In the wider portion of the body 16, as shown in [Fig. 7], a spiral groove 224 is provided, comparable to grooves 124 and 126. The exhaust air is formed from the drive air, after this air has been used to set the rotor 14 in motion around the axis X2, exerting an orthoradial force to the axis X2 on the blades 142. The spiral groove 224 opens into two cavities 226 connected to two conduits 220 and 222, which form the exhaust air conduits to the outside of the body 16. The exhaust air flow is represented by the arrows E3 in [Fig.4]. Volumes 220 to 226 together form an exhaust air manifold for turbine 12.

[0072] It is noted in [Fig.4] that the ring 32 allows the exhaust manifold 220-226 to be "masked" in a radial direction to the axis X2, vis-à-vis the outside of the body 16, in particular vis-à-vis the hood 90 which surrounds the body 2A and the turbine 12.

[0073] Thanks to the annular chamber 132 formed between the body 16 and the ring 32, radially to the axis XI6, therefore to the axis X2 in the mounted configuration of the sprayer 2, the drive air of the rotor 14 circulates in the vicinity of the outermost surface of the body 16 before being expanded, that is to say when it is at a relatively high temperature, on the order of 20 to 25°C in an automotive painting workshop where the temperature is regulated.

[0074] This allows the ring 32 to be maintained at this pre-expansion drive air temperature, or at a temperature close to this temperature. By "close," we mean that the difference between the temperature of the ring 32 and the pre-expansion drive air temperature is less than 5°C.

[0075] The material constituting the ring 32 is advantageously chosen to facilitate heat exchange with the air circulating in the chamber 132.

[0076] Thus, the ring 32 can be made of metal, for example steel or aluminum.

[0077] Since the length L32 is substantially equal to the sum of the lengths L162 and L164 and since, in steady state, the ring 32 is at a homogeneous temperature, its contact with the air circulating in the chamber 132 allows it to avoid water condensation along the entire length L162+L164 of the portion of the body 16 made up of parts 162B and 164, which is the portion of this body which has the largest dimensions transversely to the axis X2 and the axis XI6.

[0078] At the level of chamber 132, the ring 32 is not in contact with parts 162B and 164. In particular, the ribs 36 extend at a distance from surfaces S162 and S164, in a direction radial to axis XI16. In other words, a clearance J36, radial to axis X16 and of non-zero thickness, exists between each rib and the surface S162 or S164 opposite that rib. This allows the circulation of the drive air in a direction parallel to axis X16 in chamber 132, between the outlets of elbows 128 and 130.

[0079] The ring 32 is provided with two lugs 38 arranged on either side of the ribs 36, each of which has a frustoconical surface 382, ​​positioned opposite the ribs 36. The frustoconical surfaces 382 converge towards each other as they approach the axis X16. Each frustoconical surface 382 is inclined at approximately 45° with respect to the axis X16 and bears against a sealing gasket 40, which, in its unconstrained configuration, is an O-ring and is compressed within a triangular receiving volume 42. A first volume 42 is formed between a first lug 38 and portion 162B of body 16, while a second volume 42 is provided between the second heel 38 and the base 164.

[0080] The lugs 38 are also not in contact with the surfaces S162 and S164, due to the existence of a radial clearance between these lugs and these surfaces. Thus, the ring 32 is not in direct contact with the body 16.

[0081] Given the respective orientations of the frustoconical surfaces 382 of the two heels 38, the compression of the O-rings 40 has the effect of exerting on the ring 32 a clamping force which immobilizes the ring 32 on the body 16. In addition, this compression of the O-rings 40 has the effect of fluidly isolating the chamber 132 from the outside of the body 16 and of preventing a transmission of cold between the body 16 and the ring 32 by conduction.

[0082] Since the sprayer 2 is an electrostatic sprayer, it includes the subassembly 56 which is brought to high voltage when the sprayer is operating and which surrounds the front part of the turbine 12. This subassembly 56 is one of the components of the sprayer 2 and defines channels 58 for the circulation of a conforming air of the cloud of coating product droplets leaving the edge of the bowl, this subassembly 56 being sometimes referred to as the "conforming skirt".

[0083] In the case of an externally charged sprayer, the parts of the sprayer 2 carried to high voltage include electrodes not shown.

[0084] Alternatively, the sprayer may not be electrostatic. In this case, it is devoid of high-voltage parts and electrodes.

[0085] Since the ring 32 is metallic in the example, it must be avoided that it be at a floating electrical potential, especially because of the high voltage applied to the subassembly 56, which is on the order of -60 to -100 kV.

[0086] A device 60 for maintaining the ring 32 at the electrical potential of the body 16 is constituted by a helical spring made of electrically conductive material, in particular metal, disposed in a blind hole 64 of the body 16 and which pushes a ball 66, in a radial and centrifugal direction with respect to the axis XI6, against the internal peripheral surface 322 of the ring 32. Thus, even if it is not in contact with the body 16 at the ribs 36 and the heels 38, the ring 32 is maintained at the electrical potential of the body 16 by the device 60.

[0087] Thanks to the invention, the chamber 132, which forms part of the supply duct for the rotating chamber 26 to the drive air, allows the air passing through it to maintain the ring 32 at a relatively high temperature, equal to or close to that of the drive air entering the body 16. This means that the outer peripheral surface of the body 16 in its widest part, which is formed by the outer peripheral surface 324 of the ring 32, is not at risk of being at a temperature that could induce water condensation, even if the air exhaust circuit The exhaust which includes portions 220 to 229 is also provided in this part of the body 16. This control of the temperature of the peripheral surface 324 of the ring 32, therefore of the peripheral surface of the body 16, takes place without overconsumption of air since the air which passes through the intermediate chamber 132 is part of the driving air in rotation of the rotor 14 of the turbine 12.

[0088] Thus, the hood 90 of the sprayer 2 is not at risk of its temperature dropping in the vicinity of the widest part of the body 16 to the point that condensation droplets would form on its outer surface, even if the air in the coating booth in which the sprayer 2 is located has a high relative humidity, for example, above 55%. The surface temperature of the sprayer 2, at the level of the hood 90, is thus controlled by limiting a drop in the temperature of the hood 90 that could result from the circulation of exhaust air.

[0089] The risks of deterioration of the applied coating product layer are therefore minimized thanks to the invention.

[0090] According to one aspect of the invention shown only in [Fig.3], a temperature sensor 35 is integrated into the base 164 and allows the temperature of the air passing through the intermediate chamber 132 to be detected, and therefore the temperature of the ring 32 to be estimated.

[0091] Alternatively, the sensor 35 is installed to directly detect the temperature of the ring 32 or that of the hood 90.

[0092] The invention makes it possible to implement a method for controlling the surface temperature of the sprayer 2, at the level of the hood 90. This method includes a step of supplying the rotation chamber 26 with drive air, during which a flow of drive air, represented by the arrows E2, is diverted towards the area 168 of the body 16, more particularly towards the intermediate chamber 132, to control the temperature of this part 168. This limits a drop in the temperature of the part 168 and the hood 90 and prevents water from condensing in the vicinity of this area 168, in particular on the hood 90.

[0093] Advantageously, the output signal from sensor 35 is supplied to a control unit (not shown) for the sprayer 2, which is configured to adjust the operating parameters of the sprayer. For example, a computer in the control unit can be programmed to decrease the rotational speed of the rotor 14 if the temperature detected by sensor 35 approaches the dew point temperature, within 2°C. Furthermore, this unit can be configured to send an alert message to a master control unit for the temperature or humidity of the air present in a cabin in which the sprayer 2 is located, depending on the temperature detected by sensor 35. For example, if the detected temperature As sensor 35 approaches the dew point temperature, within 2°C, the main control unit can increase the ambient air setpoint temperature or decrease its relative humidity.

[0094] Parts 20, 22 and 56 are part of the body 2A of the sprayer 2.

[0095] According to an unshown embodiment of the invention, the ribs 36 are replaced by a thread formed on the internal peripheral surface 322 of the ring 32.

[0096] According to another, unshown, embodiment of the invention, air circulation can take place within a duct internal to the ring 32, for example a helical duct. This is particularly feasible with a ring 32 manufactured by 3D printing.

[0097] According to another variant, the internal peripheral surface 322 of the ring 32 is smooth, i.e. without relief.

[0098] According to another variant of the invention, the ring 32 can be made of a material other than metallic, in particular of a plastic, composite or ceramic material.

[0099] According to another variant of the invention, only a part of the drive air flow circulating in the conduit 122 is directed towards the chamber 132. To do this, a direct communication, of reduced diameter, is provided between the elbow 128 and the groove 126, by means of a conduit 140 which is represented in center lines in [Fig.3] only.

[0100] According to another unrepresented variant of the invention, chamber 132 is supplied with drive air from the two conduits 120 and 122 and the two grooves 124 and 126 are supplied from chamber 132.

[0101] According to another variant not shown of the invention, the spring 62 is in direct contact with the ring 32, without interposition of the ball 66.

[0102] According to another unrepresented variant of the invention, the elbows 128 and 130 are not arranged in the same radial plane with respect to the axis XI6, but are angularly offset around this axis.

[0103] Alternatively, the peripheral zone 168 can be defined as a zone of the body 16 whose diameter is greater than 75%, preferably 90%, of the diameters D162B and DI 64.

[0104] According to another variant not shown of the invention, the chamber 132 can be defined, radially to the axis X2, between the body 12 and the hood 90. In this case, the hood 90 constitutes a ring, in the sense of the ring 32 of the embodiment shown in the figures, without having to add an additional part compared to known sprayers.

[0105] According to an unshown embodiment of the invention, the component fed by the duct that includes the intermediate chamber 132 is not the turbine 12, but the subassembly 56 that defines the channels 58. In this case, the air that circulates in the chamber intermediate 132 is the skirt air, intended to pass through the channels 58 and which is used to conform the cloud of coating product droplets leaving the edge of the bowl 10 when the sprayer 2 is operating.

[0106] According to yet another, unshown, embodiment of the invention, the component fed by the duct that includes the intermediate chamber 132 is not the turbine 12, but a microphone used to measure the rotational speed of the rotor 14. In this case, the air flowing through the intermediate chamber is supply air to one or more cavities, unshown, attached to the rotor. The microphone is installed downstream of these cavities to detect the frequency of noise induced by the airflow in the cavities and transmit a corresponding signal to a processing unit that determines the rotational speed of the rotor based on this frequency.

[0107] The invention can be implemented for coating the bodies of motor vehicles, vehicle components, the casing of household appliances and more generally for any application of a rotary sprayer of coating product.

[0108] The embodiments of the variants envisaged above can be combined to generate new embodiments of the invention.

Claims

Demands

1. A rotary coating product sprayer (2) comprising a spray bowl (10) rotating about an axis of rotation (X2) and an air turbine (12) for driving the bowl rotating about the axis of rotation, this turbine comprising a rotor (14) and a body (16) forming a support for the rotor and defining at least one air supply duct (120-132) for a component (12, 56) of the sprayer, characterized in that the air supply duct (120-132) for the component (12, 56) of the sprayer comprises an intermediate chamber (132) defined radially to the axis of rotation (X2) between the body (16) and a ring (32, 90) mounted around this body, and in that the ring (32) is provided, on its internal radial surface (322), with at least one relief, in particular ribs (36) or a net, configured to promote heat exchange between, on the one hand, the air circulating in the intermediate chamber (132) and, on the other hand, the ring.

2. Sprayer according to claim 1, characterized in that the supply conduit (120-132) which includes the intermediate chamber (132) is the conduit which supplies the rotation chamber (26) with drive air for the turbine (12).

3. Sprayer according to claim 1, characterized in that it is equipped with a component (56) defining air circulation channels (58) conforming a cloud of droplets leaving the edge of the spray bowl (10) and in that the duct which includes the intermediate chamber supplies these channels with skirt air.

4. Sprayer according to claim 1, characterized in that it is equipped with at least one cavity, integral with the rotor (14), and a noise-measuring microphone for an airflow from the cavity to determine the rotation speed of the spray bowl (10) and that the conduit which includes the intermediate chamber supplies the microphone with air through the cavity.

5. Sprayer according to any one of the preceding claims, characterized in that the body (16) comprises a tubular part (162) which defines a housing (VI6) for receiving the rotor (14) and a base (164) which closes the housing opposite the bowl (10) and in that the ring (32) is mounted around both the tubular part and the base.

6. Sprayer according to any one of the preceding claims, characterized in that the ring (32) is made of metal.

7. Sprayer according to any one of the preceding claims, characterized in that it comprises a sub-assembly (60) for balancing electrical potential between the ring (32) and the body (16), this sub-assembly being provided in particular in the form of an electrically conductive elastically deformable member (62) bearing, directly or via an added electrically conductive element (66), against the ring (32) and against the body (16).

8. Sprayer according to any one of the preceding claims, characterized in that the ring (32) is immobilized around the body (16) by wedging.

9. Sprayer according to the preceding claim, characterized in that at least one sealing gasket (40), preferably two sealing gaskets, is or are interposed between the body (16) and the ring (32) and contribute(s) to the clamping of the ring around the body.

10. A pulverizer according to any one of the preceding claims, characterized in that the intermediate chamber (132) is provided around a part (162B, 164) of the body in which is provided a collector (220-226) of exhaust gas from the turbine (12).

11. Sprayer according to any one of the preceding claims, characterized in that it is equipped with a temperature sensor (35) for determining the air temperature in the intermediate chamber (132), the temperature of the ring (32) or the temperature of a hood (90) of the sprayer (2).

12. A method for controlling the surface temperature of a rotary coating product sprayer (2) comprising a spray bowl (10) rotating about an axis of rotation (X2) and an air turbine (12) for driving the bowl rotating about the axis of rotation, this turbine comprising a rotor (14) and a body (16) forming a support for the rotor, this method comprising a step of supplying air to a component (12, 56) of the sprayer, the supply step comprising a substep of diverting a flow (E2) of supply air from the component (12, 56) to a peripheral area (168) of the body (16) and to an intermediate chamber (132) defined radially to the axis of rotation (X2), between the body (16) and a ring (32, 90) mounted around this body, characterized in that the ring is provided, on its radial surface internal (322), of at least one relief, in particular of ribs (36) or of a net, to limit a lowering of the temperature of a dressing element (90) of the sprayer (2).

13. A method according to the preceding claim, wherein the sprayer is according to claim 11, characterized in that a control unit of the sprayer is configured to adjust the operating parameters of the sprayer (2), or of a cabin in which the sprayer is installed, according to the output signal of the sensor (35).

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