FR2832331A1 - Motor vehicle painting line applicator rinsing circuit for paint changing has retaining cylinder and scrapers with detector to control feed of flushing fluid - Google Patents

Abstract

The motor vehicle paint line applicator rinsing circuit has a line station mounted between the return and feed branches of the paint circuit and equipped with a retaining cylinder (10) and a scraper detector (15). The cleaner injects a rinsing fluid (PR1,2) behind the scrapers via solenoid valves (7,8). The rinsing fluid is drained through the station by solenoid valves (6,7,11) or through the return regulator (16) via a solenoid valve (9).

Description

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 The present invention relates to an autonomous, upgradeable and removable device for scraping closed-circuit pipes intended for rinsing produced lines with the aim of increasing their efficiency, reducing their duration as well as the economic and environmental impact by reduction of toxic effluents. This invention can be applied in particular in the automotive industry to the cleaning of paint lines but also to any process having similar constraints.

 Currently, in the automotive industry, each color is conveyed in an independent circuit and corresponds to a pumping group having its own return regulator. In addition, rinsing a line, carried out without a scraper by direct injection of solvent into the pipeline, is a costly step in terms of solvent, paint and time: this step generates large quantities of non-recoverable paint / solvent mixture, lasts 3 to 5 days and remains of poor efficacy at the low points.

There is currently no scraping device capable of remedying all of these drawbacks while meeting maintenance criteria (disassembly during production, ease of cleaning, compatibility, interchangeability, etc.), safety of use (simplicity of implementation, efficiency of the process, automation ...), scalability (number of scrapers, variety of rinsing products ...) and compactness sufficient for operation in an industrial environment. Existing systems in the agro-food, petroleum or pharmaceutical industries in particular remain in open circuit with a departure station and an arrival station forming an integral part of the product circuit which prohibits any intervention during production. These devices have never been the subject of advanced applications in the field of painting and are moreover of a fairly large size.

The device according to the invention makes it possible to bring the following improvements: - Reduction of the material investment and simplification of the pumping groups by using a circuit and a return regulator common to all the colors (the device mainly targets medium diffusion tones); - Recovery of almost the entire product (> 95%); - Considerable reduction in the amount of rinse aid required; - Increase in the efficiency of cleaning the line, particularly at the risers downstream from the low points; - Possibility of using several rinses, at least one of which may be incompatible with paint and / or other rinses thanks to the isolation possibilities allowed by the device (the use of several rinses can allow improve the efficiency of pipeline cleaning);

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 - Total independence of the pigging station which is no longer crossed during the production phase by the product flow which facilitates the maintenance of its elements, its disassembly or even its pure and simple transfer to another product line of the same diameter without obligation production stop; - Perfect interchangeability possible by adoption of a dimensional standard depending on the diameter of the product line but independent of the station's pigging capacity or the number of options selected; - Scalability possible by standardized implementation, on the base station as described in its preferred embodiment, of the connections that it needs in the form integrating all the options; - Reduction of the time for making colors available to 4 hours maximum.

 However, this device imposes a minimum quality of the product line which is part of the constraints imposed by any scraping process (constant pipe diameter, reduced bending ovality tolerance, assembly and valve elements in real full flow and with retention restricted, rolled tube welded with laminated cord, hyper-soaked, regular welds without shrinkage or protrusion).

 Figure 1 attached shows the operating principle diagram of the invention in its preferred embodiment (2 scrapers, 1 rinse aid). The device according to the invention is drawn in bold lines, the annexed devices and the circuit produced in thin lines.

 Figures 2,3, 4,5, 6,7 and 8 annexed illustrate all the functional steps of the method of implementing the device according to the invention in its preferred embodiment.

 FIG. 9 appended represents the operating principle diagram of the invention bringing together the various optional embodiments (more than 2 scrapers, second rinsing product, third shade, possibility of rinsing the head strand of the station).

 In order not to overload the diagrams (Fig. 1 to 9) and make them more readable, no manual valve or instrumentation element not directly linked to the automation of the implementation process has been shown.

 Figures 10, 11 and 12 attached show a possible variant of the invention produced here in one piece, equipped with a manual loading device of the scrapers without dismantling the station. These figures correspond respectively to the front view (Fig. 10), to the top view (Fig. 11) and to the section along AA 'of Figure 10 (Fig. 12).

 The device according to the invention consists of a single scraper station of compact linear morphology (Fig. 1): - mounted as a branch between the return and departure strands of the product circuit to be treated;

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 - totally isolated from it by two lock solenoid valves (3) and (4); - independently supplied with rinse aid (PR1) by the solenoid valve (5); provided with a drain ensuring the elimination of the mixture generated by the cleaning operation or used rinsing product (PRU) by controlling the solenoid valves (6) for that of the station and (9) for that of the return strand containing in particular the regulator (16). The bypass solenoid valve (11) connects the two supply (PR1) and drain (PRU) circuits in order to evacuate the used rinse aid conveyed between the scrapers (RI) and (R2) and downstream of it. this ; provided with a scraper retaining cylinder (10), intended to ensure that they are stopped when they return at the end of the cycle but also the emptiness of the removable outlet connection (17), as well as a detector station (15) whose function is to inform the automation of the proper recovery of the scrapers; made removable by the use of fittings (17) (18) (19) (20) and (21) on the various connection circuits of the station; upgradeable by making, in anticipation of the installation of the various options, blind connections (22) (25) (26) and (27) as well as a sleeve (23 ') between removable (28) (29) intended to replace the optional solenoid valve (23) in the basic preferred configuration.

 This completely autonomous device is also supplemented by a battery of start (12), intermediate (13) (13 ') etc., and return (14) detectors, of one or more viewfinders (24) (24' ) etc. intended to provide information to automatic controls or to visually follow the route of the pigs in the product circuit. The solenoid valve (30), worn on this circuit, symbolizes all of the manual or automatic use stations which are connected to it. The regulator (16) common to all the lines is installed on the bypass of the return strand to which the product solenoid valves (2A) (2B) are connected.

 The correct functioning of the station requires that the nozzle of the used rinse aid drain controlled by the solenoid valve (6) is located in the same axis as the cylinder rod (10) and that the axis of the product injection nozzle flushing valve (PRl) controlled by the solenoid valve (7) is located at a distance from the previous one equal to the length of the scraper (RI) increased by the radius of the cylinder rod (10). The following tappings controlled by the solenoid valves (8) (8 ') etc. are separated by the length of a scraper.

 In the context of the preferred embodiment, the rinsing process implemented with a view to changing the product (from product A to product B) was divided into 7 steps (Fig. 1):

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In the initial configuration during production (product distribution A, step 0), the station is completely isolated from the product circuit (Fig. 2): - The pump of product group A is operating, that of product group B is at 'stop; - Only the product A solenoid valves (1A) and (2A) are open, all the other solenoid valves (1B) (2B) (3) (4) (5) (6) (7) (8) (9) and (11 ) are closed; - The scrapers (RI) and (R2) are in station and the retention cylinder (10) is out.

 Step 1 (Fig. 3) corresponds to stopping the production of product A and to ejecting the scraper (RI): - The pump of product group A is stopped and the product solenoid valve (1A) closed. At the end of these first two actions, product group A is isolated from the distribution circuit and production stopped; - The opening of the lock valve (3) and the withdrawal of the jack (10) allow the ejection of the scraper (RI) by pressurizing the rinse aid behind (RI) obtained by opening the solenoid valves ( 5) and (7). The ejection is controlled by the departure detector (12) and visually by the viewfinder (24 ').

Step 2 (Fig. 4) corresponds to the ejection of the scraper (R2). A time delay (tl) or the passage of the scraper (RI) in front of an intermediate detector (13) (13 ') etc. allows to fix the quantity of rinse aid injected between the two scrapers (RI) and (R2): - The rinse aid is routed at the rear of the second scraper (R2) by closing the solenoid valve (7) and opening the solenoid valve (8) to allow ejection; - The ejection of the scraper (R2) is, as in step 1, controlled by the detector (12) and the viewfinder (24 ');
Step 3 (Fig. 5) corresponds to the recovery of product A in the work tank of group A. A time delay t2 or the passage of the scraper (RI) in front of one of the detectors (13) (13 ') etc ., fixes the quantity of rinse aid injected behind the scraper (R2). The lock (3), supply (5) and switch (8) solenoid valves are closed and the pump of the color group B is activated after opening of the product solenoid valve (IB). Product B then pushes the last train of rinse aid without interposing the scraper.

 Intermediate detectors (13) (13 ') etc. can allow the progress of the pigs to be monitored by the automatic control system and the product A contained in the circuit can be fully recovered in the product tank A through the common return regulator (16) and the product return solenoid valve (2A ).

 Step 4 (Fig. 6) corresponds to the return of the scraper (RI) to the station after it has passed in front of the return detector (14) and the closing of the product return solenoid valve (2A). The

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 drain (6) and return lock (4) solenoid valves are open to allow this return by depressurization of the station upstream of (RI). The remainder of product A is discharged into the spent rinse aid circuit (PRU). The passage of the scraper (RI) in front of the detector (15) controlling its return to the station completes the step.

 Step 5 (Fig. 7) corresponds to the recovery of the first train of used rinse aid. It begins with the closing of the solenoid valve (6) following the return of the scraper (RI) in abutment on the cylinder rod (10) then by the opening of the solenoid valve (9) to allow rinsing of the line at through the return regulator (16) either for a period (t3), fraction of the time delay (tl) or until detection of the scraper (R2) by the return detector (14). At the end of this period, the solenoid valve (9) is closed and the solenoid valves (7) and (11) open to obtain, by depressurizing the station, the emptying of the end of the first train of rinse aid in the circuit ( PRU) and the return of the scraper (R2) to the station by the same process as for step 4. Passing (R2) in front of the station detector (15) ends the step. The lock solenoid valve (4) can then be closed.

 Step 6 (Fig. 8) corresponds to the return to production of product B. It begins with the reopening of the solenoid valve (9) either for a period t4, fraction of the time delay t2, to complete the cleaning of the regulator of return (16) by the second train of rinse aid either until product B starts in the circuit (PRU) and ends with the opening of the product return solenoid valve (2B) directing the new product to the group B work tank.

The solenoid valve (9) is then closed. At the end of this last stage, product B is in production and the station again completely isolated from the product circuit.

 The device, as described in its preferred embodiment, can evolve with the aim of increasing the effectiveness of the scraping (multi-scraper option), of expanding the functional possibilities of the station (option of second rinsing product) or of reducing the impact of nuisance linked to retention impossible to completely eliminate (options with flush diaphragm valves and rinsing of the head of the station) (Fig. 9). It can also be provided with a device facilitating the installation or the manual or automatic change of the scrapers without dismantling the station (manual scraper loader option) (Fig. 10 to 12). These options are described below.

 In order to improve the quality of scraping, the device according to the invention can operate with an undetermined number of scrapers. In general, for operation with N scrapers of length L, the station is described as follows: - A jack whose rod is of radius R in front of which is carried out the drain connection controlled by the solenoid valve (6) ; - A second injection nozzle for rinsing product (PRl) or (PR2), located at the distance (L + R) from this first connection, and controlled by the solenoid valve (7);

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 (N-1) nozzles on which the switch valves (8), (8 ') are placed etc. and whose axes are spaced by the length L.

 In this case, solenoid valves (8 ') etc. are installed by means of blind connections (26) on the supply side of the rinse aid supply (PR1) or (PR2) and (25) etc. station side and step 2 of the functional description of the implementation process must be repeated as many times as there are scrapers by replacing the solenoid valve (7) with the (8) etc., the (8 ) by the (8 ') etc. and the scraper (R2) by the (R3) etc.

 Likewise, the device according to the invention can admit several different rinsing products (PR2). In this case, a solenoid valve (5 ') is connected to the station by means of the dismountable (27) on the feed side and (19') on the feed side (PR2). The functional description of the implementation process is then modified: the supply of rinse aid (PR2) by opening the solenoid valve (5 ') replaces the supply of rinse aid (PR1) by opening the solenoid valve (5).

 The potential retention zones have been identified by a double line in Figures 1 and 9.

 Among these, the zones located in the vicinity of the product solenoid valves (1A) (2A) (1B) and (2B) which are relatively small can be eliminated, at the cost however of limiting the product flow rate, by replacing the solenoid valves involved. by flush diaphragm solenoid valves.

 The area between the solenoid valves (3) and (6), the cylinder (10) and the scraper (RI) can be removed by adding an additional rinsing step. This requires adding to the circuit (PRU) of the station a solenoid valve (23) between the removable (28) and (29) replacing the cuff (23 ') blocking the emptying of rinse aid to the circuit (PRU) and replace the lock solenoid valve (3) with a 3-way solenoid valve, the third way of which would be connected to this same circuit via the connection (22). A rinsing cycle of this circuit, completely independent of the rinsing of the product circuit, can then be initiated by opening the solenoid valves (5) for supplying rinsing product (PR1) or (5 ') in product (PR2) if the option several rinsing products are available, bypass (11) and drain (6) used here against the current, correct switching of the product to the circuit (PRU) being allowed by closing the isolation solenoid valve (23 ).

 The device according to the invention can be modified in order to facilitate manual loading and handling of the scrapers (Fig. 10, 11 and 12). In this case, the station produced here in the form of a drilled block can be provided with a cover (31), of length at least greater than the length of a scraper, located upstream of the jack (10) and secured to the station body (32) by screws, the fixings of which are identified by the marks (33) (cover drilling) and (34) (body tapping).

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L'étanchéité entre le corps (32) et le couvercle (31) est assurée au moyen d'un joint de type torique épousant la forme du contour du couvercle (31) et passant dans l'échancrure (35). f
De façon plus générale, la réalisation de la station sous forme monobloc permet d'envisager diverses possibilités d'alimentation manuelle ou automatique des racleurs (tiroir, barillet, injecteur...).

The seal between the body (32) and the cover (31) is ensured by means of an O-ring type matching the shape of the outline of the cover (31) and passing through the notch (35). f
More generally, the realization of the station in one-piece form makes it possible to envisage various possibilities of manual or automatic feeding of the scrapers (drawer, barrel, injector, etc.).

 The device according to the invention is particularly suitable for scraping paint lines in the automotive industry with a view to rinsing carried out at the time of the color changes.

 It can nevertheless be applied, in general, to the scraping of all incompressible fluids a priori without viscosity limit (the compressibility imposes tolerance constraints, in particular in terms of bending ovalization which, because of their implications economical, limit their implementation and in the absence of which the variations of the scraping / tube friction forces induce pressure waves in the fluid responsible for a saltatory movement of the scrapers and detection errors which can adversely affect the monitoring of the process by automatic control).

Claims (10)

1) Autonomous, upgradeable and removable device for scraping closed-circuit pipes intended for rinsing product lines, characterized in that it consists of a single station of compact linear morphology mounted as a branch between the return and departure strands of the product circuit to treat, completely isolated from it by two solenoid valve locks (3) and (4), supplied independently with rinse aid (PR1) by the solenoid valve (5) or (PR2) by the solenoid valve (5 ') which can be injected between the various scrapers or downstream of the latter via the solenoid valves (7) (8) (8') etc., provided with a drain of the used rinse aid (PRU) controlled by the of the solenoid valves (6) for that of the station and (9) for that of the outer strand containing in particular the return regulator (16), the two circuits (PR1) and (PRU) being connected by a bypass solenoid valve (11 ) to allow the emptying of products from worn flushing (PRU) carried between the various scrapers and downstream of the latter, fitted with a scraper retaining cylinder (10) and a station detector (15), made removable by interposition of the fittings (17) (18 ) (19) (19 ') (20) and (21) and upgradeable by blind connections (22) (25) (26) (27) and the cuff (23').  2) Scraping device according to claim 1 characterized in that the closure and isolation of the station, intended to remove it from the crossing by the product flow for maintenance or transfer to other product lines and to allow automation of the process by the automatic return to the station of the scraper (s) at the end of the cleaning cycle in the exact configuration in which they were at the start of the cycle, are obtained by mounting in bypass between the return and departure strands of the product to be treated pipeline and interposition of the lock valves (3) and (4).  3) Scraping device according to claims 1 and 2 characterized in that the dismantling of the station is obtained by interposition between the latter and the lock valves (3) and (4) as well as those for supplying products rinsing (5) (5 ') and draining (6) (9) and (23), removable connectors (17) (18) (19) (20) (21) or (19') allowing the loading of or scrapers, their replacement, their cleaning or the change of their seals, the maintenance of the various elements of the station or even the transfer of the latter to another product line designed to accept a similar device.  4) Scraping device according to claims 1, 2, and 3 characterized in that the scalability of the station in its preferred embodiment, corresponding to its ability to accept the installation of various options, is obtained by the standard realization of the blind connection (22) and a sleeve (23 ') between removable (28) (29) for rinsing the head end of the station, and <Desc / Clms Page number 9>  blind connections (25) (26) for the multi-scraper option and (27) for the second rinse aid option (PR2).  5) Scraping device according to any one of the preceding claims, characterized in that the pig train can accept an unlimited number of elements (RI) (R2) (R3) etc. by the adoption of a linear morphology and the implementation of a number of nozzles for dispensing the rinsing product as high as necessary for the implementation of this function, ie 1 nozzle downstream of each of the pigs, the center distance is equal to the length L of the scrapers and controlled by the solenoid valves (7) (8) (8 ') etc., these nozzles ensuring both the supply of rinsing products downstream of the various scrapers and their ejection in the circuit produces only the emptying of this same circuit during the depressurization phase which precedes their return to the station.  6) Scraping device according to any one of the preceding claims, characterized in that its compatibility with other similar devices not having the same number of scrapers is obtained by adoption of a dimensional standard depending only on the diameter of the line produced. and consisting in fixing the overall dimension of the station between the demountables (17) and (18) on the basis of a maximum number of scrapers, 3 and 4 appearing to be reasonable numbers, and in making the number of blind connections (25 ) see (25 ') etc. based on this basis.  7) Scraping device according to any one of the preceding claims, characterized in that the supply of rinsing product can accept an undetermined number of different products, at least one of which may be incompatible with the product and / or the other products. rinsing, each product being injected into the feed manifold controlled by its own solenoid valve, (5) for (PR1), (5 ') for (PR2) etc. to then be switched to the back of any of the scrapers (RI) (R2) (R3) etc. by the corresponding solenoid valves (7) (8) or (8 ').  8) device for rinsing the potential retention zone between the solenoid valves (3) and (6), the jack (10) and the scraper (RI) of the scraper device according to any one of the preceding claims, characterized in that the rinse aid (PRl) or (PR2) is routed in the area between these 4 elements by opening the supply solenoid valve corresponding to the desired rinse aid (5) for (PRl) or (5 ') for ( PR2), the bypass solenoid valve (11) and the drain solenoid valve (6) crossed here against the current, the lock solenoid valve (3) of the device according to the preferred embodiment being in this case replaced by a 3-way valve, the third way of which would be connected to the draining circuit for used rinsing product (PRU) via the fitting (22), the solenoid valve (23) placed in place of the sleeve (23 ') between the removable (28) and (29) having the function of isolating this circuit from the rinse aid supply line (PRl) or (PR2). <Desc / Clms Page number 10>  9) Device for scraping closed-circuit pipes according to any one of the preceding claims, characterized in that the station, produced in the form of a drilled block and provided with a cover (31) of length at least greater than the length of a scraper to allow extraction, located upstream of the cylinder (10) and secured to the body of the station (32) by fixings identified by the marks (33) (drilling the cover) and (34) (tapping body), the seal between the body (32) and the cover (31) being ensured by means of an O-ring type matching the shape of the outline of the cover (31) and passing through the notch (35).  10) Method for implementing the scraping device according to any one of the preceding claims, characterized in that it comprises the following steps: Step 0, initial configuration: The product pump A is in operation, the product solenoid valves (1A) (2A) are open, the solenoid valves (1B) (2B) (3) (4) (5) (6) (7) ( 8) (9) and (11) are closed, the scrapers (RI) and (R2) are in station and the jack (10) released; Step 1: Interruption of product distribution A by stopping the product pump A and closing the product supply solenoid valve (lA) and ejecting the scraper (RI) obtained after opening the lock solenoid valve (3) and withdrawal of the jack (10) by opening the solenoid valves (5) and (7) and controlled by the detector (12) and possibly the sight (24 '); Step 2: Ejection of the scraper (R2) obtained after time delay (tl) or passage of (RI) in front of an intermediate detector (13) (13 ') etc. by closing the solenoid valve (7) and opening the solenoid valve (8) and controlled by the detector (12) and possibly the viewfinder (24 '), this step being, as part of the multi-valve option, repeated as much of times there are scrapers by replacing in its description the solenoid valve (7) by the (8) etc., the (8) by the (8 ') etc. and the scraper (R2) by the (R3) etc. ); Step 3: Recovery of product A in the tank of product group A after time delay (t2) or passage of the scraper (RI) in front of an intermediate detector (13) (13 ') etc. closing the solenoid valves (3) (5) and (8) and starting the pump of the product group B after opening the solenoid valve (1B); Step 4: Depressurization and return of the scraper (RI) to the station obtained after detection of (RI) by the detector (14) by closing the product solenoid valve (2A) and opening the solenoid valves (6) and (4) and controlled by the detector (15); Step 5: Recovery of the first train of depressurization rinse aid and return of the scraper (R2) to the station obtained by closing the solenoid valve (6) and opening the solenoid valve (9) to rinse the strand containing the regulator (16) either for a period (t3) fraction of (tl) or until detection of the scraper (R2) by the detector (14) then by closing of the solenoid valve (9) and <Desc / Clms Page number 11> Step 6: Launching of the distribution of product B obtained by opening the solenoid valve (9) either for a period (t4) fraction of (t2) or until the initiation of product B in the circuit (PRU) then by opening the product solenoid valve (2B) and closing the solenoid valve (9).  opening of the solenoid valves (7) and (11) for emptying the rest of the train into the circuit (PRU) and controlled by the detector (15) finally isolating the station by closing the solenoid valve (4);