DK147820B - PROCEDURE AND PLANT FOR MANUFACTURING PIPE STORES OF RESIN BONDED FIBER MATERIAL - Google Patents

Description

14782 '

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a method for producing tubular blanks of resin bonded fiber material and wherein a web of resin wetted fiber material is wrapped around a rotary mandrel and the inner surface of the wrap is hardened and the outer surface smoothed and cured, whereupon the wrap is removed from the mandrel and finished in an oven.

The known methods are to place the workpiece carried by the mandrel, in which the resin is partially polymerized, in an oven in which the polymerization is carried out. In addition to the disadvantage that a large number of mandrels are required and that these methods entail difficulties in handling items, there is also a risk that, upon contact with a heated mandrel, there will be damage to the item at the mandrel surface, as the temperature of the mandrel surface is difficult to control. In addition, the mandrels, especially when they are small in diameter, are exposed to accidental damage during treatment and handling.

2 147820

From the specification of US Patent No. 3,549,456, a method is known in which the subject, in which the resin is partially polymerized on a heated mandrel, is removed from the mandrel and immediately after winding, without intermediate measures for maintaining the dimensions, is transported to the furnace for final polymerization. -sering. Immediately after winding, or possibly after a quick smoothing of the workpiece surface on the mandrel, the work is transported further, these methods have the disadvantage that the workpiece is subjected to handling at a time when it can still be deformed, so that finished workpieces with poor appearance are obtained. . If the item is transported after a further and sufficient stabilization of the workpiece surface on the mandrel, the workpiece will be longer on the mandrel, therefore the number of workpieces which can be produced per unit time is considerably reduced.

SUMMARY OF THE INVENTION The invention seeks to alleviate these disadvantages, and for this purpose the method according to the invention is characterized in that immediately after curing its inner surface, the wrap is removed from the mandrel and caused to move between two substantially planar surfaces and in contact with these surfaces. which two surfaces are mutually effected to perform relative movement to advance the winding while rotating about its own axis, that at least one of said surfaces is heated to smooth and cure the outer surface of the winding, and that the winding is immediately thereafter placed in an oven in which the winding is advanced by simultaneous translation and rotation about its axis until curing is achieved.

The measures of the invention allow for gentle handling of the blanks immediately after their removal from the mandrel and until curing is carried out in the oven while shortening the duration of the blasting of the blanks, leading to increased productivity.

The invention also relates to a plant for carrying out the method according to the invention, which comprises a rotating mandrel for forming a winding from a web of resin-woven fiber material, means for curing the inner surface of the winding and smoothing and curing the outer surface and means for removing the winding from the dome and for curing in a furnace, the plant according to the invention being characterized in that the means for smoothing and curing the outer surface of the winding comprise two substantially planar surfaces adapted to perform a relative movement for conveying the winding so that it rotates. about its own axis, that at least one of said surfaces is heated for smoothing and curing the outer surface of the winding, and that the furnace has means for transporting the winding during continuous translation and rotation about its own axis.

The forward transport of the winding during the simultaneous rotation between said two planar surfaces allows for initial curing throughout the surface of the workpiece and the subsequent curing, still while the workpieces rotate on their own axis, ensures a very gentle handling and handling of the workpieces.

3 147820

Since the initial treatment between said planar surfaces is primarily intended to provide a fairly limited surface hardening, the blanks are still easily deformable at the time they are introduced into the furnace. To ensure equally gentle handling in the furnace, the conveying means in the furnace may conveniently consist of horizontal, transverse bars on which the coils rest without contact with each other, which bars are adapted to perform a vertical movement of the same amplitude for the individual bars, but phase-shifted from rod to rod for translation of the coils from one end of the furnace to the opposite end while simultaneously rotating about their longitudinal axis.

In accordance with a suitable embodiment of the system according to the invention, the ends of the rods may be connected to mutually displaced pivots on crankshafts, the angular displacement being such that the ends of the rods are located along a sine curve. As the crankshafts rotate, the rods move up and down like sine waves, and the items are transported forward and rotated about themselves.

The invention is explained in more detail below with reference to the schematic drawing, in which fig. 1a and 1b show a plant according to the invention, fig. 2a-2d a mechanism for tearing a web of fibrous material; 3 shows a mechanism for transporting the web pieces from the tearing mechanism to a winding mechanism; FIG. 3a shows another embodiment of the embodiment shown in FIG. 3; FIG. 4 is a perspective view of the winding mechanism; FIG. 5 is a portion of the embodiment of FIG. 4; FIG. 6 and 7 are sectional views through details of this mechanism; 8 shows the location of the winding rollers and a synchronization mechanism which keeps these rollers at a suitable distance from one another; FIG. 9 is a perspective view of the drive mechanism of the rollers; FIG. 10 shows a mechanism for transferring the coils from the winding mechanism to an apparatus for smoothing and curing the outer surface of the coils; FIG. 11 shows the apparatus for smoothing and surface hardening the coils; FIG. 12 is a top plan view of the same apparatus; FIG. 13 the furnace for curing the coils; FIG. 14 and 15 detail the mechanism for transporting and rotating the coils in the furnace, and FIGS. 16a – 16f successive images of this mechanism for translation and rotation of the coils in the furnace.

The FIG. 1a and 1b include the following parts: - A drying furnace 2 which receives from a conveyor 3 a resin-wetted felt strip 1. This furnace may be of a kind known per se and should therefore not be described in detail, - a mechanism 4 for tearing off the strip 1 into pieces 1a of a given length, - a conveyor 5 for transporting the strip pieces, - a mechanism 6 with rotating mandrel for winding the strip pieces to form tubular blanks during curing of the inner surface of the blanks, - a conveying means 7, - a mechanism 8, receiving the coils from the conveyor 7 and serving to cure and smooth the outer surface of the coils, - a furnace 9 for curing the coils, - a mechanism 10 for cutting the ends of the coils to obtain coils of given length, - a mechanism 11 for generating longitudinal slots in the coils, - a station 12 for packaging the coils.

Referring now to FIG. 2a-2d. The mechanism for tearing the felt strips comprises four mechanically rotational driven rollers operated in synchronism with the conveyor 5. The two furthest away from the arriving strip rollers 14 and 14a have a constant rotational speed corresponding to a tangential velocity V2.

The front rollers 13 and 13a are alternately driven for rotation with the tangential velocity V2 and are braked, for example, under the control of a time relay.

FIG. 2a shows the beginning of the mechanism's duty cycle. A piece of felt strip is just provided and the front end of the strip 1 is held between the rollers 13 and 13a which are disengaged and braked. The strip faces a detector means, e.g. As the strip exits the drying oven 2 at a constant velocity VI, a loop is formed in front of the rollers 13 and 13a, which remain disconnected and braked, cf. 2b.

After a given period of time, corresponding to the desired length of the strip section, the time relay initiated by the photocell 15 causes the rollers 13 and 13a to start at the tangential velocity V2. Hereby the loop disappears, cf. fig. 2c.

Once the loop has completely disappeared, the felt strip again faces the photocell 15 which is turned off, thereby again blocking rollers 13 and 13a. Due to the tensile stress exerted by the rotating rollers 14 and 14a on the felt, the felt is torn between the rollers 13, Da and 14, 14a, cf. 2d. The strip strip 1a obtained is transported further and a new cycle can begin.

147820 5

Referring now to FIG. 3. The embodiment of FIG. 3, the felt strips 1a transport from the tearing mechanism to the unwinding mechanism. It consists of a smooth hand 16 of polyamide material on which the strip can slip without the risk of being stuck while unwinding. The winding gives the felt strip a growing acceleration as the winding diameter grows.

The conveyor belt 16 is supported horizontally by a series of small diameter rollers 17 and by longitudinal guides. It is driven by a drive mechanism 18 which also drives the rollers of the tear-off mechanism.

On the side facing the felt strip winding mechanism, the chassis supporting the band 16 is terminated by an extremely height adjustable roller 19. This means allows the felt strips to be positioned in the proper position for winding.

Instead of such a conveyor with conveyor belt, a conveyor as shown in FIG. 3a, the conveyor comprising the rollers 13, 13a and 14, 14a, as well as the belt 16 and a height adjustable roller 19, the speed of the rollers and the belt speed increasing during the winding of the felt strip while controlling the speed of the roller 14a from a tachometer 18a associated with one of the rollers. the rollers that cooperate with the dome for the purpose of winding the felt strip.

FIG. 4-9 shows an apparatus for producing the coils. This apparatus comprises a heated dome consisting of two parts 20 and 20a, and three rollers 21, the axis of which is parallel to the axis of the dome, and which is disposed approximately 120 ° at an angle off the dome. These rollers which act as guide rollers are mechanically connected to each other and progressively remove from the axis of judgment as the winding is formed.

The mandrel parts 20 and 20a are mounted on slides 22 which move across transverse rails 23 located within a housing 24. The sledges can move over ball guide 33 and rollers 33a. The rotation of the mandrel parts 20 and 20a is achieved by means of a motor 25 and a transmission shaft 26. The slides 22 are actuated by pressure cylinders 27 for moving the mandrel parts.

The rollers 21 are driven in rotation by a drive shaft 28, through a reduction gear 29. The distance from the roller 21 to the axis through the mandrel is obtained by a rotatable arm 30, which is connected by rods to a pressure cylinder 31, which arms are mounted on end plates 34 The ends of these arms slide into guide slots 35. A set of lug rings 36 allows for power supply to resistors with which the mandrel parts 20, 20a can be heated.

The operation of this apparatus is explained below: Before a piece of felt strip 1a arrives, the ends of the two halves 20, 2oa of the mandrel are in contact with each other. The parts of the mandrel are heated to approx. 400 ° C. The front end of the felt strip comes into contact with the mandrel, and adheres to the mandrel to form the first winding. The inner surface of the wrap is cured while the strip is wound. The mandrel rotates at a constant speed of, for example, 80 to approx. 800 rpm per minute and felt strips are wound at a growing tangential velocity. The three rollers 21, which are mechanically connected to each other, slowly disassemble, exerting constant pressure on the winding being manufactured. At the end of the winding operation and due to the rapid polymerization of the resin on the inner surface, the winding is detached from the mandrel, on which it is still retained rotating by the rollers 21. The movement of the rollers away from each other and the rotation of the mandrel is interrupted when the winding is complete. This period, in which the winding is held in place and in rotation by the rollers 21, aims to further treat the wrap by smoothing its surface in contact with the rollers.

When this operation is completed, the rollers 21 quickly remove from the halves 20 and 20a of the dome, and the winding descends. Immediately after the fall of the winding, the rollers are brought back toward the mandrel parts and they control these parts as they return to abutment against each other, at the same time causing them to turn again. Thereafter, a winding cycle can begin.

The wrap 1b emanating from this apparatus has an inner hard and smooth surface which is obtained as soon as there is contact between the felt strip and the heated mandrel, as well as an outer surface which has been smoothed first by the action of the rollers 21.

The duty cycle of the mandrel and rollers can be controlled from a photocell where the light bundle to the photocell is interrupted by the portion of the felt strip conveyed across the band 16 which determines the beginning of the duty cycle after a time determined by the duration of movement from the photocell to the mandrel.

FIG. Figure 10 illustrates the mechanism for transferring the coils from the apparatus described above to the apparatus for smoothing and curing the outer surface of the coil.

This mechanism receives the coils 1b in a trough 40 located horizontally under the winding mechanism. This gutter is firmly connected to a support frame 41 which is pivotally mounted about a shaft 42 and caused to rotate by means of a pressure cylinder 43. At the end of the movement of the pressure cylinder, the winding which is supported over its entire length by means of the gutter 40 rolls. from this trench and .. is placed across a conveyor belt for the polymerization apparatus.

FIG. 11 and 12 show this apparatus for polymerizing the outer surface of the wrap.

The apparatus comprises a carrier chassis 44 having the form of a dual portal, which is provided at the top with a hoist for the height adjustment of a heating plate 45, which is equipped with electric heaters. This hoist comprises a motor gear 7 with electric brake and with four height adjustment screws 47 which are simultaneously controlled from the motor gear. These screws are connected to the heating plate 45 through longitudinally straight bars 48 connected to the heating plate by braces 49. In this way, the heating plate is supported horizontally by these screws.

Below, the apparatus comprises a belt 50 driven by a motor gear 51 which is spaced horizontally between two rollers 52. The upper branch of the belt is supported by small diameter rollers 53. The belt is operated by means of two chains, which are located at each side of the belt · The heating plate 45 is heated to a temperature of approx. 400 ° C.

They, by means of the transfer mechanism, transmit coils 1b pass between the belt 50 and the plate 45 and move forward as they rotate about their own axis under the influence of the belt and from a slight pressure from the plate. In this way, the windings are communicated to the required outer diameter and their outer surface stabilized. Due to the heat applied from the plate, the outer surface of the coils is polymerized which gives a smooth surface of satisfactory appearance, thereby making any further grinding unnecessary.

The polymerization furnace will now be described in more detail with reference to FIG.

13-16f. The coils emanating from the apparatus described above are transported further to the furnace 9, in which a complete and uniform curing of the coils is carried out at a temperature of approx. 250 ° C for polymerization with minimal smoke and gas formation. During this heat treatment, the coils are transported without mechanical impact to avoid disassembling the outer layers and without impact or friction which could cause surface defects to damage the appearance of the coils. During their stay in this furnace, the wrappers are supported over their entire length and they perform at least δη complete rotation about their own axis to obtain a uniform heat treatment.

Immediately after their exit from the apparatus in which the outer surface is smoothed, and to take full advantage of the heat supply which occurs upon contact with the heating plate, the individual windings are received in a lifting member comprising a gutter 54 which is fixedly connected to the rod of a pressure cylinder 56. A photocell detects the presence of a winding and the transfer of the guide wire to the upper floor of the furnace. During this vertical transport, the position of the winding is transversely corrected by centering guide. At the end of the movement of the pressure cylinders, the gutter 54 tilts and the winding rolls into the oven. A door 61, driven from a pressure cylinder 62, stops the winding briefly before being inserted into the furnace. This forces the winding to run parallel to the bars 63 mentioned below in the oven. The door opening is time controlled and of limited duration to reduce the heat losses from the oven.

Claims (2)

In order to extend the duration of the coils' stay in the furnace and at the same time limit the length of the furnace, the furnace comprises several floors, for example five floors in the example shown here. In each floor there is a layer of transverse rods 63, the ends of which rest on the pivots 64 on a crankshaft 65. The ends of the rods 63 are controlled in vertical slots 66 in metal profiles 67. The angular displacement between the individual pivots is such that the rods form a rug with sinusoidal profile. In the embodiment shown, there are six 60 ° angular offset pivots for complete rotation of the crankshaft. The crankshafts are provided with a rotary motion by means of a motor gear 68 through a chain 69 engaged by a sprocket 70 on the crankshafts. Due to the continuous rotation of the crankshafts, the blanket formed by the rods 63 will continually deform while maintaining a constant wavelength and amplitude. As a result, both a translational motion and a rotational motion for the windings are obtained. FIG. 16a-16f show the movement of the winding as the crankshaft rotates, these individual figures corresponding to successive rotations of the crankshaft of 60 °. Because of its own weight, the winding is held at the bottom of the wave while it deforms so that the winding moves forward and at the same time rotates about its own axis. At each floor there are two crankshafts with such an increase and the windings pass through the furnace over its entire length. After passing on the last transverse bar on a given floor, the windings fall down to the underlying floor, where they again perform the same movement as in the previous case and again perform a horizontal translation in the opposite direction. The lower level winders roll over an inclined plane 71. The furnace is heated by gas burners 72 located below the bottom 73 of the furnace, while above the individual burners are stainless steel caps 74 which serve to avoid a local overheating of the lower floor. A homogeneous distribution of the upward hot air through the furnace is ensured by a thin perforated metal plate 75 which is parallel to the upper edge of the caps 74 and spaced a certain distance from these caps. A method of producing tubular blanks of resin-bonded fiber material and wherein a web of resin-woven fiber material is wound around a rotary mandrel and the inner surface of the winding is cured and the outer surface is smoothed and cured, the winding is removed from the mandrel and cured in an oven, characterized in immediately after curing its inner surface, the wrap is removed from the mandrel and caused to move between two substantially planar surfaces and in contact