Valve and system for coating a covering product including such a valve

Abstract

Valve and system for coating a covering product comprising such a valve. The valve (4) comprises a body (8) which comprises an inner central orifice (10) and a chamber (12), the valve further comprising a piston (24) formed by a rod (240) and a piston head (242) mounted in the chamber (12), the rod (240) extending outside the body (8) and being adapted to move in an orifice (6) of the coating system (2). The valve comprises a first sealing means (26) which is received in the body (8) around the piston rod (240) on the side of the valve where the piston rod extends outside the body (8), a part (12A) of the chamber (12) being adapted to be filled with a pressurized control fluid (F2) to obtain a movement (F3) of the piston (24) against the force of a spring (34) received in the body (8). The valve comprises a second sealing means (38) which is received in the body (8) around the piston rod (240) between the first sealing means (26) and the chamber (12). The valve comprises a discharge pipe (40) which is provided in the piston rod (240) and which is in communication with the inner central orifice (10) between the first sealing means (26) and the second sealing means (38) and opens out in an open-air or in a part (12B) of the chamber (12) in communication with the open air.

Description

Technical Field

[0001] The present invention relates to a valve and a system for coating a covering product including such a valve.

Background Art

[0002] A system for applying a covering product, such as a sprayer, includes at least one valve that controls a needle that can be actuated to allow the circulation of paint. This valve is generally controlled by injecting pressurized control air into a chamber. The pressurized air acts on a piston of the control needle. Such a valve includes sealing means that, on the one hand, prevent paint from entering the valve towards the chamber and, on the other hand, prevent the pressurized control air from escaping from the chamber and prevent other fluids from entering the chamber.

[0003] Such a valve is equipped with a drain port, i.e., a passage that allows, in the case of a valve that leaks at the seal on the paint side, the paint to be directed to the outside of the sprayer and, in particular, prevents the paint from entering the control air circuit to protect the control part of the valve. The drain port also allows the leaking valve to be located.

[0004] On some current valves, a perforation is made in the body of the valve to direct the paint to the outside of the valve and then, through a point facing the body of the sprayer and drilled therein, to the outside of the injector.

[0005] This type of drain port can cause damage to the sprayer due to any dried paint residue after leakage, which may clog the drain port in the body of the sprayer.

Summary of the Invention

[0006] The present invention aims to solve these drawbacks by proposing a new valve for a system for applying a covering product, on which a drain port is formed so as to avoid damage to the system for applying a covering product.

[0007] To this end, the present invention relates to a valve for a system for coating a covering product, the valve comprising a body which includes an inner central orifice and a chamber, the valve further comprising a piston formed by a rod mounted in the orifice and a piston head mounted in the chamber, the rod extending outside the body and being adapted to move in a hole of the coating system in which the valve is adapted to be mounted and in which a pressurized covering product or other fluid circulates, the valve including first sealing means formed by a dynamic seal which is received in the body around the piston rod on one side of the valve, on which side the piston rod extends outside the body, a part of the chamber being adapted to be filled with a pressurized control fluid in order to obtain a movement of the piston against the force of a spring received in the body, the valve including second sealing means formed by a dynamic seal which is received in the body around the piston rod between the first sealing means and the chamber. The valve is characterized in that it includes a discharge tube which is provided in the rod of the piston and which communicates with the inner central orifice between the first sealing means and the second sealing means and opens into the open air or into a part of the chamber which communicates with the open air.

[0008] Thanks to the present invention, the discharge function of the valve is carried out inside the valve. If the valve leaks on the paint side, then it suffices to replace the valve and the problems of known discharge orifices, in particular blockages in the body of the coating system, are avoided, which reduces maintenance operations. The total cost of the product coating system is also reduced.

[0009] According to an advantageous but optional aspect of the present invention, such a valve may incorporate one or more of the following features, which are considered in any technically admissible combination:

[0010] - The discharge tube includes at least one radial orifice which opens into the chamber of the inner central orifice which is axially located between the first sealing means and the second sealing means.

[0011] - The valve includes an indicator fixed to the piston which is configured to project outside the body based on the position of the piston and through which the discharge tube passes.

[0012] - The discharge tube is coaxial with the central axis of the piston.

[0013] - The discharge tube opens into the part of the chamber which communicates with the open air and in which the spring is mounted.

[0014] - The valve includes a pipe which passes through the body between the outer surface of the body and the chamber of the inner central orifice which is axially located between the first sealing means and the second sealing means in order to direct towards the discharge tube a leakage from a static sealing element which is inserted between the body and the hole.

[0015] The present invention also relates to a coating system for a covering product comprising a valve as described above.

Description of the Drawings

[0016] The present invention will be better understood and other advantages thereof will become more apparent from the following description of a valve and a system for coating a covering product according to its principle, which description is provided as a non-limiting example and with reference to the accompanying drawings, in which:

[0017] Figure 1 A cross-sectional view of a valve according to the present invention installed in a spraying system according to the present invention is shown.

[0018] Figure 2 is similar to Figure 1 and shows a cross-sectional view, Figure 1 of a variant of the valve.

[0019] Figure 3 is Figure 1 a perspective view of the valve and a tool according to the present invention.

[0020] Figure 4 is a perspective view of the valve from an angle opposite to Figure 3 that.

[0021] Figure 5 is Figure 3 a longitudinal cross-sectional view of the valve and the tool as shown.

[0022] Figure 6 is a longitudinal cross-sectional view of the valve engaged in the tool in an assembled configuration.

[0023] Figure 7 is a cross-sectional view of the tool and the valve along plane VII;

[0024] Figure 8 is Figure 9 a cross-sectional view of the valve and the tool assembled along plane VIII in

[0025] Figure 9 is a longitudinal cross-sectional view of the assembled valve and tool along plane IX.

Detailed Description

[0026] Figure 1 A part of a system 2 for coating a covering product is shown, for example, a sprayer for paint, varnish, anti-corrosion covering or any other conceivable type of product. The system 2 includes a valve 4 installed in a hole 6 of the system 2.

[0027] The valve 4 includes a body 8, which includes an inner central orifice 10 and a chamber 12. The orifice 10 and the chamber 12 are centered on a central axis X. Hereinafter, the terms "axial", "radial", "axially", "radially" are used with reference to the central axis X.

[0028] The orifice 10 is in fluid communication with the chamber 12. The orifice 10 emerges from the body 8 at the end face 14 of the body 8 in the hole 6.

[0029] The system 2 includes a fluid inlet conduit 16 in the hole 6 and a fluid outlet conduit 18 extending through the hole 6. In some applications, the inlet and outlet conduits can be reversed. The inlet conduit 16 and the outlet conduit 18 are mainly used for the circulation of the covering product, but other fluids, especially air or cleaning solvents, can also circulate in the inlet conduit 16 and the outlet conduit 18.

[0030] Between the inlet conduit 16 and the outlet conduit 18, the hole 6 includes a seat 20 with which the needle 22 of the valve 4 cooperates to close or allow the circulation of the covering product along the arrow F1 from the inlet conduit 16 to the outlet conduit 18. In a variant not shown, the seat 20 can also be machined directly in the material of the coating system 2. The inlet conduit 16 is connected to a covering product reservoir or a pump not shown, especially a pump of the "circulation" type, and the outlet conduit 18 is connected to a coating or spraying device not shown, such as a spray gun.

[0031] The valve 4 includes a piston 24 formed by a rod 240 mounted in the inner orifice 10 and a piston head 242 received in the chamber 12. The rod 240 extends to the outside of the body 8 and supports the needle 22. The rod 240 is intended to translate along the central axis X in the hole 6, and the pressurized covering product circulates in the hole 6 along the arrow F1.

[0032] The valve 4 includes a first sealing device 26 that is received in the body 8 around the piston rod 240 on one side of the valve 4, on which side of the valve 4 the rod 240 extends to the outside of the body 8. The first sealing device 26 is a dynamic seal that makes it possible to prevent the covering product from penetrating between the piston rod 240 and the body 8 towards the chamber 12 during the translational movement of the piston rod 240.

[0033] The piston head 242 has an axial surface 244 perpendicular to the central axis X. The piston head 242 extends radially in a skirt 246 in which a sealing device 248 is received, which ensures a dynamic seal between the piston head 242 and the inner cylindrical wall 120 of the chamber 12 during the translational movement of the piston head 242 in the chamber 12. The sealing device 246 divides the chamber 12 into two fluid-isolated parts 12A and 12B, because the sealing device 246 prevents fluid from circulating around the piston head 242 between the parts 12A and 12B.

[0034] A portion 12A of the chamber 12 is located on the side of the piston rod 240. The axial surface 244 is located in the portion 12A. The spraying system 2 includes an inlet pipe 28 for pressurized control fluid, which inlet pipe emerges in a peripheral groove 30 of the body 8. The peripheral groove 30 communicates with the portion 12A through an axial orifice 32. The portion 12A of the chamber 12 is adapted to be filled with pressurized control fluid, such as air, in order to control the axial movement of the piston 24. The valve 4 includes a spring 34 mounted in a portion 12B of the chamber 12. The spring 34 is centered on the central axis X and exerts an elastic force on the piston head 242 in order to drive it downward, that is to say, to push it into the portion 12A. The spring 34 bears against a portion of the piston head 242 and against a plug 36 of the valve 4, which plug is fastened to the body 8 and screwed into the coating system 2.

[0035] Under the control action of the compressed air injected via the pipe 28 into the portion 12A (arrow F2), the piston 24 moves upward (arrow F3) against the force of the spring 34 by the force exerted on the axial surface 244 by the pressure of the pressurized air. This causes the needle 22 to be lifted off the seat 20 and allows the covered product to lead to the discharge pipe 18.

[0036] The valve 4 includes a second sealing device 38, which second sealing device is received in the body 8 around the piston rod 240 between the first sealing device 26 and the chamber 12. The sealing device 38 is a dynamic seal, which dynamic seal prevents air from leaving the chamber 12 during the translation of the piston rod 240 and also prevents other fluids from entering the portion 12A. It is necessary to keep the pressurized control air circuit free from any intrusion of external fluids (especially the covered product).

[0037] The valve 4 also includes a number of static sealing devices, which ensure the tightness between the orifice 6 and the body 8. These devices are formed by O-rings 39 received in grooves of the body 8 and bearing against the orifice 6, in particular the O-ring ensuring the tightness between the orifice 6 and the body 8 around the end face 14.

[0038] In the case of a failure of the first sealing device 26 that may cause leakage and the inflow of the covered product towards the chamber 12, the valve 4 includes a discharge pipe 40, which discharge pipe makes it possible to discharge the covered product that has leaked towards a position separate from the portion 12A of the chamber 12.

[0039] The discharge pipe 40 is provided in the piston rod 240 and communicates with the inner central orifice 10 between the first sealing device 26 and the second sealing device 38 and emerges in the open air or in a portion of the chamber 12 communicating with the open air. The discharge pipe 40 is formed by a pipe surrounded by the material forming the piston rod 240. Thus, the vent hole 40 is provided in the valve 4 itself, which does not require a vent passage in the coating system 2. It is possible to replace a defective valve without intervening in the coating system.

[0040] In one embodiment, the discharge pipe 40 is coaxial with the central axis X of the piston 24. The discharge pipe 40 includes at least one radial orifice 42 that is exposed in the cavity 44 of the inner central orifice 10, which cavity is axially located between the first sealing device 26 and the second sealing device 38. Thus, any leakage of the covering product through the first sealing device 26 accumulates in the cavity 44 and then rejoins the discharge pipe 40 via the radial orifice 42 along the arrow F4. The discharge pipe 40 may include a plurality of radial orifices 42 distributed around the central axis X.

[0041] The valve 4 includes an indicator 46 that is formed by a portion fixed to the piston 24 and is configured to project outside the body 8 based on the axial position of the piston 24. The indicator 46 is a cylindrical portion that is coaxial with the central axis X, is fastened to the piston head 242, and is inserted into the orifice 360 of the plug 36. When the piston 24 is pushed upward under the action of the compressed control air, the indicator 46 projects outside the plug 36 and is visible from the outside.

[0042] In the illustrated example, the discharge pipe 40 extends through the perforation 460 of the indicator 46. Thus, the covering product that has leaked through the discharge pipe 40 is discharged to an open area along the arrow F4. Thus, if the first sealing device 26 fails, the covering product leaks through the piston rod 240 and then the indicator 46 (i.e., a component of the valve 4) and is discharged to an open area without passing through the spraying device 2. This does not require a special valve that must be cleaned in the event of a leak. In addition, the covering product is directed away from the portion 12A via the vent hole 40 to prevent contamination of the control air circuit.

[0043] According to a variant (not shown), the discharge pipe 40 is not coaxial with the central axis X.

[0044] According to Figure 2 In another variant shown, the discharge pipe 40 does not pass through the indicator 46 in order to discharge the covering product to an open area. For example, the discharge pipe 40 may follow a path inside the piston rod 240 and the piston head 242 through the pipes 400, which pipes 400 are exposed in the portion 12B of the chamber 12. The portion 12B communicates with the open air via the orifice 360 of the plug 36, and the indicator 46 slides along the central axis X through the orifice 360. Thus, the covering product can be discharged from the portion 12B via the orifice 360. A certain amount of the leaked covering product can accumulate around the indicator 46 and the spring 34, and advantageously blocks the valve 4 in the closed position. The portion 12A is protected from the leakage of the covering product by the dynamic sealing device 248. The blocking of the valve 4 in the closed position results in a rapid indication of the failure of the valve 4.

[0045] According to a variant not shown, the indicator 46 may also not be coaxial with the central axis X. The indicator 46 may also not be a part separate from the piston 24. The indicator and the piston 24 may be integral and form an integral part through which the discharge pipe 40 always passes between the radial orifice 42 and the open area at the plug 36.

[0046] According to an alternative aspect, the valve 4 may include a perforation 500 passing through the body 8 between the orifice 6 and the chamber 44. The opening of the perforation 500 is arranged behind the seal 39A with respect to the end face 14. Thus, in the case of a sealing problem at the seal 39A, the leakage between the outer surface of the body 8 and the orifice 6 is directed through the perforation 500 and along the arrow F5 towards the chamber 44 and then towards the radial orifice 42 and the discharge pipe 40.

[0047] See Figures 3 to 9 , additional aspects of the valve 4, a tool 52 for assembling and disassembling the valve 4, and the operation of the tool 52 are described.

[0048] The valve 4 includes a protruded or recessed shape on the peripheral part, which is configured to cooperate with the protruded or recessed shape of the tool 52. These protruded or recessed shapes are configured to transmit a rotational movement to the valve 4 and to be fixed to the tool 52 during the disassembly of the valve 4. The peripheral part is formed by a plug 54 having Figure 4 the specific shape shown, and the main function of this plug is similar to Figure 1 that of the plug 36 of

[0049] The protruded or hollow shape provided on the plug 54 includes a peripheral profile 542 and a peripheral profile 544, which is located behind the peripheral profile 542 with respect to the outer end 546 of the valve 4, and the outer end is supported by the axial surface of the plug 54. The peripheral profiles 542 and 544 are graded along the axis X, and the peripheral profile 542 is closest to the end 546.

[0050] The peripheral profile 542 has three flat surfaces 542A that extend parallel to the axis X and form a break in the cylindrical shape of the plug 54. The peripheral profile 544 includes three flat surfaces 544A that are aligned with the three flat surfaces 542A of the peripheral profile 542 and three flat surfaces 544B that are angularly offset with respect to the three flat surfaces 542A. "Aligned" means that the flat surface 544A is at least partially located in the extension of the axis X along the flat surface 542A and forms the same plane. "Angularly offset" means that the surface 544B is located in an angular sector that is offset with respect to the angular sector in which the flat surface 542A extends, such that the respective planes formed by the flat surfaces 542A and 544B are secant. This angular offset allows the flat surface 544B to form an axial shoulder 545 that is recessed with respect to the peripheral profile 542. As Figure 4 shown, the flat surface 544B retreats from the cylindrical portion of the peripheral profile 542.

[0051] The tool 52 includes a protruding or recessed shape on the peripheral portion that is configured to cooperate with a protruding or recessed shape provided on the plug of the valve 4. These protruding or recessed shapes of the tool 52 are configured to transfer a rotational movement to the valve 4 and secure to the valve 4 during the assembly or disassembly of the valve 4.

[0052] The tool 52 extends along a central axis X52 and includes a handle 520 and an end piece 522 having a hole 524. The protruding or hollow shape of the tool 52 is provided on the inner peripheral surface 524A of the hole 524. The inner peripheral surface 524A includes three flat peripheral surfaces 526, which is equal to the number of flat surfaces 542A of the peripheral profile 542 of the valve 4. The flat surfaces 526 are parallel to the axis X52 in the same way as the surface 542A is parallel to the axis X. The peripheral surface 524A also includes a groove 528 that retreats radially from the flat peripheral surface 526. The groove 528 is located behind the flat surface 526 with respect to the front end 530 of the tool 52. The groove 528 forms an axial shoulder 527 that is configured to receive a portion of the valve 4 by securing the valve 4 to the tool 52.

[0053] The groove 528 includes an elastic element 529 that, when the valve 4 is received in the tool 52, exerts an elastic force directed along the axis X52 against the portion of the valve 4 received in the groove 528. The elastic element 529 can be, for example, an O-ring. In a variant not shown, the elastic element can also be a helical spring or a lock washer (Belleville washer).

[0054] In a variation not shown, the perimeter contour 542 may include a different number of planar surfaces, more typically at least one planar surface. Similarly, the perimeter contour 544 may have a number of planar surfaces (different from three, more typically at least one) aligned with the planar surface of the perimeter contour 542 and at least one planar surface angularly offset relative to the planar surface of the perimeter contour 542. Like the planar surfaces of the perimeter contours 542 and 544, the tool 52 may have a number of planar surfaces 526 different from three, more typically at least one planar surface.

[0055] The operation of the tool 52 with the valve 4 will be described below. Figure 5 , Figure 6 as well as Figure 7 The assembly of the valve 4 in its housing is shown. The valve 4 is positioned in its hole 6 and then the tool 52 is brought closer to the valve 4 so that the axes X and X52 are combined ( Figure 5 ).

[0056] When the end piece 522 is pushed into the plug 54 ( Figure 6 ) so that the peripheral profile 542 is at least partially axially aligned with the flat surface 526, the flat surfaces 542A and 544A cooperate by making planar contact with the flat surface 526 ( Figure 7 , in which the elastic element 529 is omitted). Thus, by imparting a rotational tightening movement to the tool 52 along the arrow R1, the operator can screw the valve 4 into the hole 6.

[0057] When the operator wishes to unscrew the valve 4 and remove it, he pushes the tool 52 deeper so that the elastic element 529 is crushed. The peripheral contour 542 is axially aligned with the groove 528 ( Figure 9 ). Next, the operator applies a rotation in the unscrewing direction along the arrow R2, causing the surfaces 526 to pivot about the axis X until they come into planar contact with the flat surface 544B ( Figure 8 ). This rotation is allowed by the fact that the peripheral profile 544 has a rounded surface 544C at the junction of the flat surfaces 544A and 544B that allows rotation in the unscrewing direction.

[0058] In this configuration, the peripheral profile 542 is blocked in the groove 528 by inserting the flat surface 526 of the tool 52 into the retracted protrusion formed by the peripheral profile 544. The shoulder 527 of the tool 52 is then axially opposed to the shoulder 545 of the valve 4 and prevents the tool 52 from being removed from the valve 4. The elastic force exerted by the elastic element 529 tends to push the valve 4 back outside the hole 544, thus locking the contact between the shoulders 527 and 545. The valve 4 and the tool 52 then form an integral assembly. The valve 4 and the tool 52 form a "bayonet" assembly.

[0059] By continuing to rotate in the unscrewing direction, the operator applies a planar contact between surfaces 526 and 544B, which enables the valve 4 to be unscrewed. Once the valve is removed from the hole 6, the valve 4 can be easily removed, even from hard-to-reach positions, because the valve 4 remains attached to the end piece 522 of the tool 52. The valve 4 remains fixed to the tool 52 and there is no risk of dropping.

[0060] This possibility of attaching the valve 4 to the end piece 522 can also be used during the assembly of the valve 4 in hard-to-reach positions. The operator can fasten the valve 4 to the tool 52 before assembly by pushing the valve 4 into the hole 524 and then turning the valve 4 in the unscrewing direction. After the valve 4 is installed in its hole 6, the operator then turns the tool 52 in the tightening direction. Then, the valve 4 will rotate freely and tighten itself until the tightening encounters resistance. Then, the rotational torque of the tool 52 overcomes the force exerted by the elastic element, and the tool 52 rotates relative to the valve 4 until cooperation between the surface 526 and the surfaces 542A and 544A is obtained. Then the tightening can be continued until it is locked.

[0061] Thus, the tool 52 and the recessed / protruding projections provided on the valve 4 enable the use of the same tool for assembling and disassembling the valve. If the means for both assembly and disassembly are provided on the same end piece 522 of the tool 52, it is not necessary to rotate it in order to perform either operation. The possibility of fixing the valve 4 and the tool 52 by a bayonet assembly enables the valve 4 to be easily assembled or disassembled in hard-to-reach positions. Different from the known techniques, the unscrewing and removal of the valve can be carried out especially in a single operation. In the known techniques, two different tools are used for unscrewing and removal, and sometimes heavy replacement is required for the two tools if the valve is not unscrewed sufficiently.

[0062] In the context of the claims, the features of the above embodiments and alternatives can be combined to form new embodiments of the present invention.

Claims

1. A valve (4) for a coating system (2) for coating a covering product, said valve comprising a body (8) which includes an inner central orifice (10) and a chamber (12), said valve further comprising a piston (24) formed by a rod (240) mounted in said inner central orifice (10) and a piston head (242) mounted in said chamber (12), said rod (240) extending outside said body (8) and being adapted to move in an orifice (6) of said coating system (2), said valve (4) being adapted to be mounted in the orifice (6) and the covering product or another fluid circulating in the orifice (6), said valve comprising a first sealing means (26) formed by a dynamic seal which is received in said body (8) around said rod (240) on one side of said valve, on which side of said valve the rod extends outside said body (8), a part (12A) of said chamber (12) being adapted to be filled with a pressurized control fluid (F2) in order to obtain a movement (F3) of said piston (24) against the force of a spring (34) received in said body (8), said valve comprising a second sealing means (38) formed by a dynamic seal which is received in said body (8) around said rod (240) between said first sealing means (26) and said chamber (12). Characterized in that: said valve comprises a discharge pipe (40) provided in said rod (240) of said piston and communicating with said inner central orifice (10) between said first sealing means (26) and said second sealing means (38) and opening into a part (12B) of said chamber (12) which is open to the atmosphere or communicates with the atmosphere. said discharge pipe (40) includes at least one radial orifice (42) opening into a cavity (44) of said inner central orifice (10) which is axially located between said first sealing means (26) and said second sealing means (38). said valve comprises a pipe (500) which passes through said body (8) between an outer surface of said body (8) and said cavity (44) of said inner central orifice (10) which is axially located between said first sealing means (26) and said second sealing means (38) in order to direct a leakage (F5) from a static sealing element (39A) inserted between said body (8) and said orifice (6) towards said discharge pipe (40).

2. The valve according to claim 1, characterized in that, said valve comprises an indicator (46) fixed to said piston (24) which is configured to project outside said body (8) based on the position of said piston (24) and said discharge pipe (40) passes through said indicator (46).

3. The valve according to claim 1, characterized in that, said discharge pipe (40) is coaxial with a central axis (X) of said piston (24).

4. The valve according to claim 1, Characterized in that, the discharge pipe (40) is exposed in the part (12B) of the chamber (12) that communicates with the open air and in which the spring is installed.

5. A coating system (2) for covering a product, the coating system comprising a valve (4) according to any one of the preceding claims.

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