WO2017029644A1

WO2017029644A1 - Pipe gripping system in a pipe coating station

Info

Publication number: WO2017029644A1
Application number: PCT/IB2016/054982
Authority: WO
Inventors: Andrea ANDERLINI
Original assignee: Anderlini Meccanica S.R.L.
Priority date: 2015-08-19
Filing date: 2016-08-19
Publication date: 2017-02-23
Also published as: EP3337620A1; ITUB20153166A1

Abstract

A gripping system (100) of a pipe (TB) in a STATION VII for coating the pipe (TB). The gripping system (100) comprises: - a movable assembly (EM) to which the pipe (TB) is coupled; the movable assembly (EM) being adapted to move the pipe (TB) through the stations of a powder coating plant (PLT); and - a device (DR) for rotating the pipe (TB) about a vertical longitudinal axis (Y1). The gripping system (100) also comprises a device for the distribution of compressed air (DD) inside the pipe (TB) to prevent the accumulation of coating powder inside the pipe (TB).

Description

PIPE GRIPPING SYSTEM IN A PIPE COATING STATION

TECHNICAL FIELD

The present invention relates to a pipe gripping system in a pipe coating station.

The present invention also relates to a coating station comprising at least one innovative pipe gripping system. The present invention also relates to a coating plant comprising at least one innovative coating station.

BACKGROUND ART

The use of a metal pipe as a painted casing in which the actual electric components of the motor are then inserted is already known in the field of tubular electric motors. However, during the powder coating step of the metal pipe, before placing it in the oven, thanks to its high volatility (and to the electrostatic charge activating the powder paint), the coating also tends to deposit on the inner wall of the pipe, thus creating also an inner coating layer. In use, this jeopardizes the pipe electrical conductivity, thus making the pipe unusable in manufacturing tubular electric motors.

Therefore, the present pipe gripping system which is to be used in a powder coating plant has as specific objective to provide a perfect coating on the outer surface of the pipe, and leaving the pipe inner surface completely free of paint .

The following two methods are currently used to limit and solve this problem:

1) the first method uses a cap to be applied to at least one of the pipe ends; however, this solution has proved to be not very effective, since the end opposite to the one where the cap is applied is still open. Furthermore, when the cap is removed, the pipe outer edge shows coating films creating undesired impurities in the pipe assembling step the electric motor; moreover, from time to time, some coating accumulates in the part not protected by the cap and must then be mechanically removed, thus increasing the process cost;

2) the second method manually eliminates any residual powder by blowing air within the pipe before the polymerization; this system is certainly more effective than the first, but could involve safety problems for the operator blowing air into the pipe, since he/she might be exposed to the coating powder removed by the air blow.

DISCLOSURE OF INVENTION

Therefore, a main object of the present invention is to provide a pipe gripping system in a coating station, which is free from the aforesaid drawbacks and, at the same time, is easy and inexpensive to manufacture.

In particular, the present invention finds advantageous, but not exclusive, application in a coating plant for pipes used in the field of tubular electric motors, to which the following description will make explicit reference without thereby losing its generality.

The envisaged innovative solution is to provide a special pipe gripping system that, by entering air in the pipe, creates a positive pressure preventing the accumulation of coating powder inside the pipe, thus avoiding any manual intervention of an operator and hermetically isolating the coating area. The present system is therefore completely safe for the operators of the plant, which could be fully automated with the use of workpiece gripping robots for loading and unloading the pipes.

The present invention, therefore, provides a pipe gripping system in a coating station, as claimed in claim 1, or in any one of the claims directly or indirectly depending on claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, it is now described a preferred embodiment, purely by way of non- limiting example and with reference to the accompanying drawings, in which: - Figure 1 shows a general layout of a pipe powder coating plant using a pipe gripping system according to the teachings of the present invention;

- Figure 2 shows a three-dimensional view of a powder cabin used in a coating station belonging to the plant of Figure i;

- Figure 3 shows a longitudinal section of the powder cabin of Figure 2; and

- Figure 4 shows in detail a pipe gripping system according to the teachings of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Figure 1 indicates with (PLT) , as a whole, a powder coating plant for pipes (TB) .

As better explained below, the powder coating plant (PLT) comprises a plurality of pipe (TB) machining stations arranged in series.

The pipes (TB) are transported within the powder coating plant (PLT) by means of a single monorail conveyor device (DTM) (or a two-rail conveyor device with hook-changing stations) .

In the present case, all the operations are performed in steps, on groups of six pipes (TB) at a time.

Obviously, different types of machining cycles are possible. As shown by the layout of Figure 1, the powder coating plant (PLT) comprises:

- a first STATION I for loading the pipes (TB) ;

- a second STATION II for degreasing the pipes (TB) ;

- a third STATION III for a first rinsing of the pipes (TB) ;

- a fourth STATION IV for a second rinsing of the pipes (TB) ;

- a fifth STATION V for passivating the pipes (TB) ;

- a sixth STATION VI for drying the pipes (TB) ;

- a seventh STATIION VII for applying the coating powder on the outer surfaces of the passing pipes (TB) ;

- an eighth STATION VIII for gelling the powder applied on the pipes (TB) ;

- a ninth STATION IX for polymerizing the pipes (TB) ; and

- a tenth STATION X for draining the coated pipes (TB) . Incidentally, the structural details of the single stations will be omitted because inessential to the understanding of the present invention.

Therefore, the attention will be focused only on the powder coating STATION VII (see below) because of its relevance for fully understanding the innovative aspects of the present invention.

Figure 4 indicates with 100, as a whole, a gripping system of a pipe (TB) in a pipe coating station (TB) having a substantially symmetrical first vertical axis (Yl) .

The gripping system 100 of the pipe (TB) comprises a sleeve 50 coupled at one of its ends to a ring 51, which, as shown below, works as pipe plug (TB) .

The lower end of the sleeve 50 is provided with a plurality of openings 50A for the passage of compressed air (see below) .

The lower part of the sleeve 50 is integral with a device provided with expansion springs 52 of known type, centring the pipe (TB) with respect to the sleeve 50 and coupling them. Alternatively, the centring rods may be provided at their ends with permanent magnets that increase the retaining strength of the pipe with respect to the hook. In an embodiment not shown, instead of (or in cooperation with the) the device provided with expansion springs 52, it is provided a support in which the sleeve must be inserted; such support comprises a control cylinder to expand at least a rubber ring (not shown) arranged at the end of the sleeve to allow a correct coupling of the sleeve to the pipe to be coated.

On the opposite side of the sleeve 50, a sleeve 60 protrudes upward from the ring 51. A toothed wheel 70 having a vertical axis (Yl) is keyed to the upper end of the sleeve 60.

A perforated rod 80 on which the toothed wheel 70 idly rotates is coaxial to the pipe (TB) , the sleeve 50 and the sleeve 60.

In actual use, the sleeve 50 and the sleeve 60 rotate about the perforated rod 80, which, in turn, does not rotate. The lower end 80A of the perforated rod 80 is open and allows the passage of compressed air (see below) which is then blown inside the pipe (TB) after passing through the openings 50A (see below) made in the pipe 50.

The shape of the central pipe allows keeping an outgoing air flow at a speed such as to prevent the powder from entering the pipe.

In other words, the toothed wheel 70, the sleeve 60, the ring 51 and the pipe 50 form a device (DR) for rotating the pipe (TB) about the first vertical axis (Yl) (according to an arrow (R) ) ; the rotation of the pipe (TB) occurs whenever the toothed wheel 70 meshes with a pinion 90 driven into rotation by an electric motor (MT) about a second vertical axis (Y2) substantially parallel to said first vertical axis (Yl) .

In a known way, a speed reducer (RD) is interposed between the electric motor (MT) and the pinion 90.

As already stated, the toothed wheel 70 is idle on the perforated rod 80 and therefore this latter does not rotate, but is coupled to a driving plate 71 by means of a nut 72 and a locknut 73, both provided with a respective vertical through hole.

As always shown in Figure 4, the through hole of the locknut 73 has a flared portion coupling it to a horizontal slot 74 from which pressurized air flows out, transported by an air box 75, which extends transversely to the first longitudinal axis (Yl) .

The plate 71, in turn, is integral with a carriage 85 provided with four driving wheels (WL) engaging a fixed guide (GD) .

It is thus obtained an actual movable assembly (EM) comprising the carriage 85, the plate 71 and the perforated rod 80 moving through the various stations of the coating plant (PLT) .

The movable assembly (EM) is moved through the various stations forming the coating plant (PLT) by the aforesaid monorail conveyor device (DTM) .

Therefore, the movable assembly (EM) is associated to said rotation device (DR) and to a device for the distribution of compressed air (DD) , comprising, in turn, the air box 75, the rod 80 and the pipe 50 having the openings 50A.

Therefore, by entering the seventh STATION VII for applying the powder coating on the pipe (TB) , the pipe is simultaneously set in rotation (about the first longitudinal axis (Y) and according to the arrow (R) ) by coupling the pinion 90 to the toothed wheel 70, and is hit by a blow of compressed air that laps its inner wall, coming out of the open lower and upper ends of the pipe (TB) .

The procedure for using the gripping system consists in fastening the pipe by means of the expansion spring (possibly with permanent magnets at the ends) on a core coupled to a motor to rotate the pipe during the steps for coating and polymerising it with IR and UV lamps UV, thus ensuring a perfect uniformity and polymerisation of the applied coating powder layer.

Air is fed inside the pipe, thus preventing the accumulation of coating powder inside the pipe and ensuring a perfect cleaning inside it.

Each pipe to be coated is provided with a motorized coupling system.

According to a further embodiment not shown of the present invention, the flow of compressed air enters on the opposite side with respect to the coupling point, or even on any intermediate area of the pipe surface having an access hole.

The pipe coupling could be manufactured also by using a special frame with multiple ports to be coupled directly to the feeding chain of the coating line.

As shown in more detail in Figures 2, 3, 4 in the seventh STATION VII for powder coating there is a powder cabin (CAB) (Figures 2, 3) containing some of the devices composing the above-mentioned gripping system 100.

The powder cabin (CAB) comprises an outer coating (RIV) having a substantially cylindrical shape.

The outer coating (RIV) provides a corridor (CRD) , which, in use, is crossed by the pipes (TB) to be treated transported by said monorail conveyor device (DTM) .

As shown in more detail in Figures 2, 3, 4 the powder cabin (CAB) is provided with an opening (APR) through which coating powder distributing sprayers (LCN) are inserted as needed. Advantageously, but not necessarily, the sprayers (LCN) are mounted on a carriage (CAR) (Figure 3) , which is (with systems known and not shown) transversely moved towards (arrow (Fl)) and from (arrow (F2)) the powder cabin (CAB) .

The coating powder is distributed in a known manner on the outer surfaces of the pipes (TB) passing through the powder cabin (CAB) , blowing the coating powder with compressed air through the sprayers (LNC) .

The coating powder only deposits on the outer surface of the passing pipes (TB) and not on their inner surface because, as previously stated, the deposition on the inner surface of the pipes (TB) is prevented by the leakage of compressed air through the openings 50A made in the sleeve 50 (see above) . As already stated, by applying the coating powder, each pipe rotates about the axis (Yl) according to the arrow (R) (Figure 1) .

Looking again at Figure 1, a compressed air distributing nozzle (NZL) is advantageously arranged within the powder cabin (CAB), laterally with respect to the sleeve 60.

The compressed air jet leaving the nozzle (NZL) prevents the (unwanted) accumulation of coating powder on the outer surface of the sleeve 60 as well.

The main advantage of the pipe gripping system in accordance with the present invention is to prevent, in a simple and fully automated way, the unwanted coating powder deposition on the inner surface of the passing pipes. This has an obvious beneficial influence on the health of the operators who are no longer forced to inhale and/or to be exposed to coating powders.

Claims

1. A gripping system (100) of a pipe (TB) in a coating STATION VII of the pipe (TB) ;

said gripping system (100) comprising:

- a movable assembly (EM) to which the pipe (TB) is coupled; said movable assembly (EM) being able to move the pipe (TB) through the stations of a powder coating plant (PLT) ; and

- a device (DR) for rotating said pipe (TB) about a vertical longitudinal axis (Yl);

said gripping system (100) being characterized in that it further comprises a device for the distribution of compressed air (DD) inside said pipe (TB) to prevent the accumulation of coating powder inside the pipe (TB) .

2. Gripping system (100), according to Claim 1, characterized in that said device for the distribution of compressed air (DD) inside said pipe (TB) comprises an air box (75), a perforated rod (80) and a sleeve (50) having a plurality of openings (50A) through which the compressed air is blown inside the pipe (TB) .

3. Gripping system (100), according to anyone of the preceding Claims, characterized in that said device for the distribution of compressed air (DD) is coupled to said pipe (TB) through reversible locking means (52) .

4. Gripping system (100), according to Claim 3, characterized in that said reversible locking means (52) comprise at least one device provided with extension springs (52) and/or permanent magnets touching the inner wall of the pipe (TB) .

5. Gripping system (100), according to anyone of the preceding Claims, characterized in that the flow of compressed air enters the pipe (TN) on the side of the coupling point of the pipe (TB) .

6. Gripping system (100), according to anyone of Claims 1-4, characterized in that the flow of compressed air enters the pipe (TN) on the opposite side with respect to the coupling point, or on any intermediate area of the pipe surface having an access hole.

7. A coating station (STATION VII) of a powder coating plant (PLT) for pipes (TB) ;

said coating station (STATION VII) comprising:

- a cabin (CAB) provided with coating powder distribution means (LNC) on the outer surface of passing pipes (TB) ;

said coating station (STATION VII) being characterized in that it comprises at least a gripping system (100) according to anyone of Claims 1-6.

8. Coating station (STATION VII), according to Claim 7, characterized in that said powder cabin (CAB) contains at least a compressed air distribution nozzle (NZL) , preventing the accumulation of coating powder on parts of the gripping system (100) of the pipe (TB) .

9. Coating station (STATION VII), according to Claim 7 or to Claim 8, characterized in that said powder cabin (CAB) is provided with a corridor (CRD) for the passage of the pipes (TB) transported by a conveyor device (DTM) ; said powder cabin (CAB) being further provided with an opening (APR) through which said coating powder distribution means (LNC) are inserted.

10. Powder coating system (PLT) characterized in that it comprises at least one coating station (STATION VII) according to anyone of Claims 7-9.