Rotary coating product spray and method for controlling surface temperature of the same

Abstract

To provide a rotary coating product spray, and to provide a method for controlling a surface temperature of the spray.SOLUTION: A rotary coating product spray includes: a spray bowl which rotates around a rotation axis (X2); and an air turbine (12) for driving the bowl. The turbine includes: a rotor; and a body (16) forming a support for the rotor and defining at least one air supply line (120 to 132) for a rotation chamber (26) in which blades (142) of the rotor are disposed. The lines (120 to 132) for supplying air to the rotation chamber (26) in which the blades (142) of the rotor are disposed include an intermediate chamber (132) defined between the body (16) and rings (32, 90) attached to a periphery of the body in a radial direction with respect to the rotation axis (X2). The structure limits reduction of a temperature of an element of the spray housing caused by exhaust flow from the turbine (12).SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a rotary coating product spray that is intended to be used for applying a coating product to a surface to be coated, particularly. The present invention also relates to a method for controlling the surface temperature of such a spray.

Background Art

[0002] Rotary sprays are used, for example, to apply coatings of the paint or varnish type to the body of a vehicle, vehicle components or the housing of household appliances.

[0003] Such a spray comprises a bowl driven in rotation about an axis of rotation by a turbine, which may be an air turbine (i.e. a rotor comprising a rotor whose rotation is caused by the flow of an air stream that affects the blades rigidly connected to the rotor).

[0004] This type of spray is satisfactory overall. However, there is a problem caused by the expansion of the drive air, which has to be moved near the blades at a relatively high pressure of about 6 bar and is at a pressure close to atmospheric pressure at the outlet of the turbine. This expansion of the drive air, which exhausts after affecting the blades of the rotor, has the effect of significantly cooling the rotor over a temperature range of about 20°C.

[0005] Therefore, considering that air enters the turbine at a temperature of 20-25 degrees Celsius (°C) and a relative humidity of 55-65%, the temperature of the exhaust gas exiting the turbine may be lower than the dew point temperature of 10-18°C. This has the effect of condensing the moisture in the air to such an extent that water droplets may accumulate outside the spray, even if the turbine body is covered by a cover. These water droplets may fall from the spray onto the surface being coated during the spraying process, either by gravity or carried by the airflow. This can cause defects in the applied coating.

[0006] In practice, this is unacceptable, and attempts have been made to adjust the airflow of the air turbine to limit the risk of water condensation caused by exhaust temperature.

[0007] European Patent Application Publication No. 808089 teaches a method for directing a portion of the supply air from an air bearing to a volume in which a pressure drop may occur. The effect of this method is an increase in the overall air consumption of the spray, which requires additional resources to produce pressurized air and increases the cost of operating coating equipment equipped with such a spray.

[0008] Another known method involves inserting an electric air heater into the spray air supply line to maintain the drive air temperature at around 40°C, preventing the exhaust from reaching temperatures at the turbine outlet that could cause condensation of moisture in the air. This method is particularly energy-intensive and requires the acquisition of additional, expensive equipment. [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] The present invention aims to solve these problems by proposing a novel rotary coating product spray that significantly reduces, or even completely eliminates, the risk of water condensation on the spray surface without substantially reducing the energy performance of the spray. [Means for solving the problem]

[0010] For this purpose, the present invention provides a rotary coating product spray comprising a spray bowl that rotates around an axis of rotation, and an air turbine for driving the bowl around the axis, the turbine comprising a rotor and a body that forms a support for the rotor and defines at least one air supply line for supplying air to a rotating chamber in which the blades of the rotor are located. According to the present invention, the supply line for supplying air to the rotating chamber comprises an intermediate chamber defined radially with respect to the axis of rotation between the body of the turbine and a ring mounted around the body.

[0011] According to the present invention, an intermediate chamber in the supply line, defined between the body and a ring mounted around the body, forms a relatively high-temperature air circulation region on the outermost part of the body, which avoids a significant drop in temperature around the body in that region. This has the effect of limiting the risk of condensation of the spray in that region. The air flowing through the intermediate chamber can then be used to rotate the rotor or even to power components other than the turbine. It is understood that other components of the turbine may include an element for shaping a conical flow of paint, also called an "air skirt," or an acoustic sensor configured to measure the rotational speed of the rotor. The use of turbine element supply airflow reduces the energy consumption of the device compared to solutions that use airflow used only for limited cooling, or solutions that use devices to heat the incoming flow.

[0012] Since the rotating chamber is supplied through a line with an intermediate chamber, the air flowing through the intermediate chamber does not need to be supplied to the spray in addition to the air used for normal spray operation. In addition, as the turbine accelerates, the exhaust cools, and as the flow velocity of the supply air increases, the thermal effect of the air flowing through the intermediate chamber increases. In other words, the cooling of the turbine exhaust, and the compensation for that cooling, obtained by the ring mounted around the spray body, also develops with the turbine speed. Furthermore, since the turbine supply air is the strongest flow and has the highest flow velocity among the other flows supplying the functional components of the spray, higher heating performance is obtained. This is because a larger volume of air undergoes a heat transfer effect between the outside of the spray and the air in the intermediate chamber via the ring. In addition, since the head loss is related to the pressure and flow velocity of the supply air, the energy consumption due to the head loss depends on the energy required to rotate the spray bowl.

[0013] According to an advantageous but not essential embodiment of the present invention, such a spray can incorporate one or more of the following features in any technically acceptable combination. The supply line comprises at least one branch extending parallel to the axis of rotation, and a bent portion connecting the branch to an intermediate chamber radially with respect to the axis of rotation. The supply line comprises a spiral section perpendicular to the axis of rotation, which opens into the rotating chamber, and a bent section connecting the intermediate chamber to the spiral section. The spray has components that define channels for airflow to form a cloud of droplets leaving the edge of the spray bowl, while a supply line with an intermediate chamber supplies skirt air to the channels. The spray comprises at least one cavity rigidly connected to a rotor and a microphone that measures the noise of the airflow coming from the cavity to determine the rotation speed of the spray bowl, while a supply line with an intermediate chamber supplies air to the microphone through the cavity. The body comprises a tubular section that defines a housing to receive the rotor and a base that closes the housing on the opposite side of the bowl, while the ring is attached around both the tubular section and the base. The ring has at least one pattern of ridges, particularly ribs or threads, on its internal radial surface, configured to facilitate heat exchange between the ring and, on the one hand, with the air circulating inside the intermediate chamber, and on the other hand, with the air. The ring is made of metal. The spray comprises a subassembly for balancing the potential between the ring and the body, the subassembly being provided more specifically in the form of elastically deformable electrically conductive elements that are in contact with the ring and the body, either directly or via attached electrically conductive elements. The ring is secured around the body by a wedge fastener. At least one seal, preferably two seals, are positioned between the body and the ring to contribute to wedge-holding the ring around the body. The intermediate chamber is formed around the portion of the body where the turbine's exhaust manifold is located. The spray is equipped with a temperature sensor for determining the temperature of the air in the intermediate chamber, the ring, or the cover of the spray.

[0014] In another aspect, the present invention relates to a method for controlling the surface temperature of a rotary coating spray, comprising a spray bowl that rotates around an axis of rotation, and an air turbine for driving the bowl around the axis of rotation, wherein the turbine comprises a rotor and a body forming a support for the rotor, the method comprising a supply step of supplying air to a rotating chamber in which the blades of the rotor are located. According to the present invention, the supply step includes a sub-step of redirecting the flow of driving air for the rotor to a region around the body to limit the temperature drop of the spray's covering elements.

[0015] Advantageously, the spray control unit is configured to adjust the operating parameters of the spray or the booth into which the spray is introduced in response to the output signal of the temperature sensor.

[0016] The present invention will be better understood and the advantages thereof will become more apparent by referring to the following description of embodiments of a method for controlling a spray and its surface temperature according to the principles of the present invention, given merely by way of example, and to the accompanying drawings.

Brief Description of the Drawings

[0017] [Figure 1] It is an axial section of a rotary spray according to the present invention. [Figure 2] It is an axial section of a turbine belonging to the spray shown in FIG. 1. [Figure 3] It is an enlarged view of detail III in FIG. 2. [Figure 4] It is an axial section of the turbines of FIGS. 2 and 3 taken in a plane offset around the axis of rotation with respect to the planes of FIGS. 2 and 3. [Figure 5] It is an exploded perspective view of the turbines of FIGS. 2 to 4. [Figure 6] It is a perspective view of the turbines of FIGS. 2 to 5 following arrow VI in FIG. 2, and the base is omitted for clarity of the drawing. [Figure 7] It is a perspective section of the turbines of FIGS. 2 to 6, and the base is shown separated from the rest of the turbine and viewed at different angles.

[0018] The electrostatic spray 2 shown in FIG. 1 is attached to the list 4 of a multi-axis robot 6 shown very schematically. The list 4 is an interface region 8 through which pass the not-shown supply lines of the spray 2 for fluids (fluids including turbine drive air, skirt air and liquid coating material), and the power cables for high voltage components, defining the interface region 8.

[0019] Sprayer 2 includes a bowl 10 designed to rotate about an axis X2 defined by a body 2A of the sprayer 2. The bowl 10 is an air turbine 12 that includes a rotor 14 that is rotatable about the axis X2 and to which the bowl 10 is rigidly attached, and a body 16 that forms a support for the rotor 14, and is rotated about the axis X2 by the air turbine 12.

[0020] The body 2A includes a main portion 20 into which the turbine 12 is inserted and that is in contact with the interface region 8, and an auxiliary body 22.

[0021] The turbine 12, which is one of the components of the sprayer 2, is shown separately in FIG. 2 and the following figures.

[0022] The rotor 14 and the body 16 are hollow and together define a volume V18 that forms a housing for receiving a coating product injector 18 for transporting the flow of the liquid coating product to be sprayed using the bowl 10 as close as possible to the bowl 10.

[0023] Here, advantageously, the injector is along the axis X2.

[0024] The rotor 14 includes blades 142 formed on an annular and axial surface 143 of a ring 144 attached around a hub 146. The number, distribution, and shape of the blades with respect to the intended rotational speed of the bowl 10 depend on the design considerations of the rotor 14.

[0025] Alternatively, other structures are possible for the rotor 14. For example, the portions 144 and 146 may be integral, or the blades may be formed on the peripheral surface of the rotor 14.

[0026] The body 16 comprises a tubular portion 162 and a base portion 164 centered on longitudinal axes X162 and X164, respectively. In the assembled configuration of the body 16, axes X162 and X164 coincide and define the central axis X16 of the body 16. In the assembled configuration of the spray 2, axes X2 and X16 coincide.

[0027] As shown in Figures 2 and 4, the tubular portion 162 defines a volume V14 for receiving the rotor 14, which is introduced into the receiving volume V14 from below, while in these figures, the base 164 closes this volume from below. The volume V16 is centered on the axis X16.

[0028] Two air bearings, not shown, are formed on either side of the ring 144 along the axis X2. The bearings allow the rotor 14 to be positioned relative to the body 16 in volume V16 and along the axis X2 when air is supplied to it. The air bearings enable non-contact rotation of the rotor 14 within the body 16. The air bearings are involved in centering the rotor 14 along the axis X2 and are sometimes referred to as axial air bearings.

[0029] On the other hand, radial air bearings are formed around the rotor 14 in volume V16 and within a tubular portion 162. The radial air bearings allow the rotor 14 to be centered on axis X16 inside the housing 16.

[0030] In one embodiment, the bearings of the turbine 12 may be roller bearings.

[0031] In the assembled configuration of the turbine shown in Figures 1-4 and 6, the blades 142 are positioned in a rotating chamber 26 formed between portions 162 and 164 of the body 16, in the portion left open by the rotor 14.

[0032] The base 164 is fixed to the tubular portion 162 by a plurality of screws 167 that traverse the base from side to side parallel to the axis X164 and are received by corresponding internal threads of the tubular portion 162.

[0033] The screw 28 passes through the tubular portion 162 and the base portion 164, respectively, across the bores 282 and 284, and secures the turbine 12 to the main portion 20.

[0034] The tubular portion 162 has a stepped external shape. Specifically, portion 162 has an annular cross-section around axis X162 and includes a front portion 162A that is positioned on the side of the bowl 10 when the bowl 10 is in place (i.e., facing forward of the spray), and the front portion 162A has a first external diameter D162A. Portion 162 further includes a rear portion 162B that is on the opposite side of the bowl 10 when the bowl 10 is mounted (i.e., facing backward of the spray), and the rear portion 162B has a second external diameter D162B that is strictly larger than the first diameter D162A. The base portion 164 also has an annular cross-section around axis X164 and has an external diameter D164 identical to the diameter D162B. Thus, portions 162B and 164 constitute the portion of the body 16 having the largest diameter.

[0035] Instead, portions 162 and / or 164 do not have an annular external cross-section. In this case, the tubular portion is stepped in the sense that the maximum external dimension of the front portion 162A in the lateral direction relative to the axis X162 is strictly smaller than the maximum external dimension of the rear portion 162A in the lateral direction relative to the axis X162. Furthermore, portions 162B and 164 constitute the body portion having the maximum lateral dimension relative to the axis X16.

[0036] The front section 162A is surrounded by an auxiliary body 22, which supports adjacent components and forms a flow line not shown. The auxiliary body 22 is sometimes referred to as an "internal skirt". The auxiliary body 22 is made of a thermally insulating material, such as plastic, and isolates the front section 162A from the cover 90 that covers the turbine body 16 and the auxiliary body 22.

[0037] The keying pin 30 allows the turbine 12 to be oriented around the axis X2, rearward relative to the main portion 20 and forward relative to the internal skirt 22.

[0038] The rotating chamber 26 is supplied with air to rotate the rotor 14 through two ducts 120 and 122, which in turn are supplied with air through ducts 80 and 82 formed in the main section 20.

[0039] The duct 120 is straight and, in this example, parallel to the axis X16, and connects directly to the groove 124 in a helical portion centered on the axis X16. The duct 120 is formed in the base 164, while the groove 124 is formed in the tubular portion 162. The flow of drive air through the body 16 along this first path is indicated by arrow E1 in Figures 2 and 6.

[0040] The duct 122 is also connected to a second groove 126 in a helical portion centered on axis X16, the second groove 126 leading to the chamber 26 and formed within the tubular portion 162.

[0041] Here, grooves 124 and 126 are formed in portion 162 symmetrically with respect to axis X162.

[0042] In practice, in this example, grooves 124 and 126 are formed on the surface of portion 162B facing the base 164 and extend perpendicularly to axes X162 and X16, and therefore perpendicular to axis X2 in the assembled configuration of spray 2.

[0043] The duct 122 is straight and, in this example, parallel to axis X2, and connects to a bent portion 128 that opens to the circumferential surface S164 of the base 164, facing the ring 32 that surrounds both portions 162B and 164 of the body 16.

[0044] On the other hand, the bent portion 130 is provided within the annular portion 162 and opens to the outer peripheral surface S162 of portion 162B.

[0045] Surfaces S162 and S164 are on the same plane and have the same diameter, either D162B or D164, which corresponds to the ring 32 having the same diameter along its length L32, parallel to the axis X2.

[0046] In one embodiment, if the diameters D162B and D164 are different, the ring 32 may have a stepped shape.

[0047] On the opposite side of the opening to the surface S162, the bent portion 130 is connected to the helical groove 126.

[0048] Along the radial direction with respect to axis X2, an annular chamber 132 is formed on one side between surfaces S162 and S164 and the internal radial surface 322 of ring 32. The annular chamber 132 constitutes part of the supply line for chamber 26 by the driving air, and the supply line consists of volumes 122, 128, 132, 130 and 126, through which the driving air flows, as shown by the flow arrow E2 in Figures 2, 3 and 6. Chamber 132 is located between the inlet of the supply line, which is the mouth of duct 122, and the outlet of the supply line, which is the outlet of duct 136 to the rotating chamber 26.

[0049] The bends 128 and 130 allow the drive airflow E2 to be redirected radially with respect to the ducts 122 and 126, with respect to the axis X16, and therefore with respect to the axis X2 in the assembled configuration of the spray 2. In this way, the drive air can flow through the peripheral region 168 of the body 16, which is radially further from the axis X16 than the ducts 120 and 122.

[0050] The radial inner surface 322 of the ring 32 is provided with ribs 36 that create multiple baffles inside the chamber 132, thereby increasing the contact area between the air flowing between the bends 128 and 130 inside the chamber 132 and the ring 32. Thus, the ribs 36 are configured to facilitate heat exchange between the driving air flowing through the chamber 132 and the ring 32.

[0051] The axial length of ring 32, that is, the length of the ring measured parallel to axis X16, is represented by L32.

[0052] Furthermore, L162 represents the axial length of portion 162B of the tubular portion 162 when measured parallel to axis X162, and L164 represents the axial length of the base portion 164 when measured parallel to axis X164.

[0053] In the example, length L32 is equal to the sum of lengths L162 and L164. In practice, the ratio L32 / (L162+L164) is selected to be greater than 0.8, preferably greater than 0.95. In other words, the ring 32 encloses the widest part of the body 16 for most of its length when measured parallel to the axis of rotation.

[0054] In one embodiment, the ratio L32 / (L162+L164) may be strictly greater than 1.

[0055] As shown in Figure 7, a helical groove 224 corresponding to grooves 124 and 126 is provided in the widest part of the body 16. After the drive air is used to operate the rotor 14 around the shaft X2 by applying a positively radiating force to the blades 142 with respect to the shaft X2, exhaust is formed by the drive air. The helical groove 224 leads to two cavities 226 connected to two ducts 220 and 222, which form an exhaust duct to the outside of the body 16. In Figure 4, the exhaust flow is represented by arrow E3. Volumes 220-226 together form an exhaust manifold for the turbine 12.

[0056] Figure 4 shows that the ring 32 "conceals" the exhaust manifolds 220-226 from the outside of the body 16, particularly from the cover 90 surrounding the body 2A and the turbine 12, in a radial direction relative to the axis X2.

[0057] In the assembled configuration of spray 2, the drive air for the rotor 14 flows near the outermost surface of the body 16 before it is expanded (i.e., while it is at a relatively high temperature of about 20-25°C in a temperature-controlled car paint shop) through an annular chamber 132 formed between the body 16 and the ring 32, radially with respect to axis X16 and therefore axis X2.

[0058] In this way, the ring 32 can be kept at the temperature of the drive air before expansion, or a temperature close to it. "Close to" means that the difference between the temperature of the ring 32 and the temperature of the drive air before expansion is less than 5°C.

[0059] Advantageously, the constituent material of the ring 32 is selected to facilitate heat exchange with the air flowing through the chamber 132.

[0060] Therefore, the ring 32 may be made of metal, for example, steel or aluminum.

[0061] When length L32 is substantially equal to the sum of lengths L162 and L164, and when ring 32 is at a uniform temperature under steady conditions, contact of ring 32 with air flowing through chamber 132 prevents ring 32 from condensing water over the entire length L162 + L164 of the body 16 portion consisting of portions 162B and 164, which is the portion of body 16 having the greatest dimensions laterally with respect to axes X2 and X16.

[0062] In chamber 132, ring 32 is not in contact with portions 162B and 164. In particular, ribs 36 extend radially with respect to axis X116, away from surfaces S162 and S164. In other words, a gap J36 with a non-zero thickness exists radially with respect to axis X16 between each rib and the surface S162 or S164 facing the rib. In this way, the driving air flows in chamber 132 between the openings of the bent portions 128 and 130, in a direction parallel to axis X16.

[0063] The ring 32 is provided with two stubs 38 positioned on both sides of the rib 36, each having a frustoconical surface 382 positioned opposite the rib 36. The frustoconical surfaces 382 converge toward each other as they approach the axis X16. Each frustoconical surface 382 is angled approximately 45° with respect to the axis X16 and is adjacent to a seal 40, which is an O-ring in an unloaded configuration and is compressed in a receiving volume 42 having a triangular cross-section. The first volume 42 is formed between the first stub 38 and a portion 162B of the body 16, while the second volume 42 is formed between the second stub 38 and the base 164.

[0064] Because there is a radial clearance between the stub 38 and surfaces S162 and S164, the stub 38 does not come into contact with either surface S162 or S164. Therefore, the ring 32 does not come into direct contact with the body 16.

[0065] Given the orientation of the frustoconical surfaces 382 of the two stubs 38, the compression of the O-ring 40 has the effect of applying a wedging force to the ring 32, which secures the ring 32 to the body 16. In addition, the compression of the O-ring 40 has the effect of fluidly isolating the chamber 132 from the outside of the body 16, thereby preventing the transfer of cooling between the body 16 and the ring 32 by conduction.

[0066] Since spray 2 is an electrostatic spray, spray 2 is subjected to a high voltage when the spray is in operation and includes a subassembly 56 that surrounds the front portion of the turbine 12. This subassembly 56 is one of the components of spray 2 and defines a channel 58 for the flow of forming air to create a cloud of droplets of the coating product leaving the edge of the bowl, and the subassembly 56 is sometimes referred to as a “forming skirt”.

[0067] In the case of an externally charged spray, the high-voltage portion of spray 2 includes electrodes not shown.

[0068] In one embodiment, the spray does not have to be electrostatic. In this case, the spray does not have a high-voltage part and electrodes.

[0069] In this example, since ring 32 is made of metal, it should not be at a stray potential, and especially due to the high voltage applied to the subassembly 56, it should be around -60 to -100 kV.

[0070] The device 60 for holding the ring 32 at the potential of the body 16 consists of a spiral spring made of an electrically conductive material, particularly metal, positioned in a blind hole 64 of the body 16, and pushing a ball 66 radially and centrifugally with respect to the axis X16 toward an adjacent portion of the ring 32 toward the inner peripheral surface 322. Thus, although the ring 32 does not come into contact with the body 16 at the ribs 36 and stub 38, it is held at the potential of the body 16 by the device 60.

[0071] According to the present invention, the chamber 132, which constitutes part of the supply line that supplies drive air to the rotating chamber 26, allows the air flowing through it to maintain the ring 32 at a relatively high temperature equal to or close to the temperature of the drive air at the inlet of the body 16. In this way, the outer peripheral surface of the body 16 at its widest portion, formed by the outer peripheral surface 324 of the ring 32, should not reach a temperature that could cause water condensation, even if an exhaust discharge circuit including portions 220-229 is further formed on the body 16. Since the air flowing through the intermediate chamber 132 is part of the air used to rotate the rotor 14 of the turbine 12, temperature control of the peripheral surface 324 of the ring 32, and therefore the peripheral surface of the body 16, is achieved without excessive consumption of air.

[0072] Therefore, even if the air in the coating booth where the spray 2 is located has a relatively high relative humidity, for example, a relative humidity of more than 55%, the cover 90 of the spray 2 is not at risk of condensation droplets forming on its outer surface in the vicinity of the widest part of the body 16 at its temperature. Thus, the surface temperature of the spray 2 at the level of the cover 90 is controlled by limiting the temperature drop of the cover 90, which may be caused by the exhaust flow.

[0073] Therefore, the risk of damaging the layer of the coating product to which it is applied is minimized by the present invention.

[0074] According to one aspect of the present invention shown only in Figure 3, a temperature sensor 35 is incorporated into the base 164, enabling detection of the temperature of the air flowing through the intermediate chamber 132, and thus the estimation of the temperature of the ring 32.

[0075] In one embodiment, the sensor 35 is introduced to directly detect the temperature of the ring 32 or the temperature of the cover 90.

[0076] The present invention enables the implementation of a method for monitoring the surface temperature of the spray 2 at the level of the cover 90. The method includes the steps of supplying drive air to a rotating chamber 26, in which case the flow of drive air, represented by arrow E2, is redirected to a region 168 of the body 16, more specifically to an intermediate chamber 132, to control the temperature of this portion 168. This limits the temperature drop of the portion 168 and the cover 90 and prevents water from condensing in the vicinity of this region 168, particularly on the cover 90.

[0077] Advantageously, the output signal from sensor 35 is provided to a control unit of spray 2 (not shown) configured to adjust the spray's operating parameters. For example, the computer in the control unit may be programmed to reduce the rotational speed of rotor 14 when the temperature detected by sensor 35 approaches within 2°C of the dew point temperature. In addition, the unit may be configured to send an alert message to a main control unit for the temperature or humidity of the air present in the booth where spray 2 is located, based on the temperature detected by sensor 35. For example, if the temperature detected by sensor 35 approaches within 2°C of the dew point temperature, the main control unit may raise the set temperature of the ambient air or decrease its relative humidity.

[0078] Parts 20, 22, and 56 are parts of the body 2A of the spray 2.

[0079] According to an embodiment of the present invention not shown, the rib 36 is replaced by threads provided on the inner peripheral surface 322 of the ring 32.

[0080] According to another embodiment of the present invention, air circulation can be performed in an internal line of the ring 32, for example, in a spiral line. In particular, this may be done by a ring manufactured using 3D printing.

[0081] According to another embodiment, the inner peripheral surface 322 of the ring 32 is smooth, i.e., it does not have a pattern of undulations.

[0082] According to another embodiment of the present invention, the ring 32 may be made of a material other than metal, particularly a plastic material, a composite material, or a ceramic material.

[0083] According to another embodiment of the present invention, only a portion of the flow of driving air through the duct 122 is directed towards the chamber 132. For this purpose, a reduced diameter direct communication is formed between the bend 128 and the groove 126 by a line 140, which is shown only by a center line in Figure 3.

[0084] According to another embodiment of the present invention not shown, the chamber 132 is supplied with driving air from two ducts 120 and 122, and two grooves 124 and 126 are supplied from the chamber 132.

[0085] According to another embodiment of the present invention (not shown), the spring 62 is in direct contact with the ring 32 without the ball 66 being interposed.

[0086] According to another embodiment of the present invention (not shown), the bent portions 128 and 130 are not arranged in the same radial plane with respect to axis X16, but are angularly offset with respect to axis X16.

[0087] In another embodiment, the peripheral region 168 may be defined as a region of the body 16 whose diameter is greater than 75%, preferably greater than 90%, of the diameters D162B and D164.

[0088] According to another embodiment of the present invention not shown, the chamber 132 may be defined radially with respect to axis X2 between the body 12 and the cover 90. In this case, the cover 90 constitutes a ring in the sense of the ring 32 of the embodiment shown in the figure, without the need to add any further parts compared to known sprays.

[0089] According to an embodiment not shown in the figures of the present invention, the component supplied by the line including the intermediate chamber 132 is not the turbine 12, but a subassembly 56 defining the channel 58. In this case, the air flowing through the intermediate chamber 132 is skirt air, which is intended to pass through the channel 58 and is used to form a cloud of droplets of the coating product that leave the edge 10 of the bowl when the spray 2 is operating. In this case as well, it is not necessary to supply the spray with air flowing through the intermediate chamber in addition to the air used to bring the normal spray operation. This embodiment can be used independently or in addition to the embodiment shown in the figures.

[0090] According to yet another, not-illustrated embodiment of the present invention, the component supplied by the line including 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 the supply air to one or more cavities, not illustrated, that are rigidly connected to the rotor. The microphone is introduced downstream of the cavities to detect the frequency of noise induced by the airflow in the cavities and transmit a signal corresponding to a calculation unit that determines the rotational speed of the rotor based on that frequency. Furthermore, this means that it is not necessary to supply air flowing through the intermediate chamber to the spray in addition to the air used for the normal spray operation. This embodiment can also be used independently or in addition to the embodiments shown in the figures.

[0091] The present invention can be implemented for coating vehicle bodies, vehicle components, and household appliance casings, and more generally for any application of rotary spray for coating products.

[0092] By combining the embodiments of the versions of the embodiments considered above, new embodiments of the present invention can be created.

Claims

1. A rotary spray (2) for a coating product, comprising a spray bowl (10) that rotates around an axis of rotation (X2), and an air turbine (12) for rotating the bowl around the axis of rotation, wherein the turbine comprises a rotor (14) and a body (16) that forms a support for the rotor and defines at least one supply line (120-132) for supplying air to a rotary chamber (26) in which rotor blades (142) are arranged, and wherein the supply line (120-132) for supplying air to the rotary chamber (26) comprises an intermediate chamber (132) defined radially with respect to the axis of rotation (X2) between the body (16) and a ring (32, 90) attached around the body. A spray characterized by this.

2. The spray according to claim 1, characterized in that the supply line (120-132) comprises at least one branch portion 122 extending parallel to the axis of rotation (X2) and a bent portion (128) connecting the branch portion to the intermediate chamber (132) radially with respect to the axis of rotation.

3. The supply line (120-132) is a spiral portion (126) perpendicular to the axis of rotation (X2) opening into the rotary chamber (26), and a bent portion (130) connecting the intermediate chamber (132) to the spiral portion. The spray according to claim 1 or 2, characterized by this.

4. The body (16) comprises a tubular portion (162) defining a housing (V16) for receiving the rotor (14) and a base (164) closing the housing on the opposite side of the bowl (10), and the ring (32) is attached around both the tubular portion and the base. The spray according to claim 1 or 2, characterized by this.

5. The ring (32) is provided on its inner radial surface (322) with at least one pattern of undulations configured to promote heat exchange, on the one hand, between the air circulating inside the intermediate chamber (132) and, on the other hand, between the ring and the spray according to claim 1 or 2.

6. The spray according to claim 5, characterized in that the pattern of undulations consists of ribs (36) or threads.

7. The spray according to claim 1 or 2, characterized in that the ring (32) is made of metal.

8. The spray according to claim 1 or 2, characterized in that it comprises a sub-assembly (60) for equalizing the potential between the ring (32) and the body (16).

9. The spray according to claim 8, characterized in that the sub-assembly is provided in the form of an elastically deformable electrically conductive element (62) in contact with the ring (32) and the body (16) either directly or via an attached electrically conductive element (66).

10. The spray according to claim 1 or 2, characterized in that the ring (32) is fixed around the body (16) by means of a keying.

11. The spray according to claim 10, characterized in that at least one seal (40) is arranged between the body (16) and the ring (32) and contributes to the keying of the ring around the body.

12. The spray according to claim 11, characterized in that two seals (40) are arranged between the body (16) and the ring (32) and contribute to the keying of the ring around the body.

13. The spray according to claim 1 or 2, characterized in that the intermediate chamber (132) is formed around the part (162B, 164) of the body in which the manifold (220 - 226) of the exhaust gas from the turbine (12) is formed.

14. The spray according to claim 1 or 2, characterized in that it comprises a temperature sensor (35) for determining the temperature of the air in the intermediate chamber (132), the temperature of the ring (32) or the temperature of the cover (90) of the spray (2).

15. A method for controlling the surface temperature of a rotary coating product spray (2), comprising a spray bowl (10) rotating around an axis of rotation (X2) and an air turbine (12) for rotating the bowl around the axis of rotation, the turbine comprising a rotor (14) and a body (16) forming a support for the rotor, the method comprising a supply step of supplying air to a rotating chamber (26) in which the blades (142) of the rotor are arranged, the supply step comprising a sub-step consisting of converting a flow of drive air (E2) for the rotor into a peripheral region (168) of the body (16) to limit a decrease in the temperature of a cover element (90) of the spray (2).

16. The method according to claim 15, characterized in that the spray is the spray according to claim 14 and the control unit of the spray is configured to adjust the operating parameters of the spray (2) or of the booth into which the spray is introduced according to the output signal of the sensor (35).

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