Folded-seam connection, method of producing it and device

Description of the invention

The subject of the invention is an turned-over flange connection and a method and device for its production.

Folded flange connections between two ductile metal pipes, pipe sections, pipe segments, or pipe bends are well known in the field of ventilation and air conditioning. An inherent disadvantage of these connections is the lack of tightness, since after each folded flange connection has been produced, springback occurs, i.e. in the direction of opening. The resulting leakage losses of this type of connection are often unacceptable in terms of hygiene, health and safety and / or energy, so additional sealing measures are necessary, for example by inserting a rubber band and / or joining the flanged flange connection by gluing; see, among others WO 00/27557, Figures 10 to 13, which show different ways of joining seals.

This leads to further inconvenience. In addition to the expense of high-quality materials and the time it takes to insert additional sealing material into the flanged flange, its effectiveness essentially depends on the diligence of the contractor (worker). Additionally, even synthetic sealing materials become brittle and withstand only small pressure differences, especially when large gaps and / or shear forces are present.

Methods and devices for producing such known turned flange connections are also known.

A highly airtight, flanged flange connection between two ductile metal pipes, pipe sections, pipe segments or pipe bends, used to convey the flowing gases, according to the invention, is characterized by having a double flange flange at the first pipe end surrounded by a second double flange on the second the ends of the pipe to form at least a partial fit with an all-round metal seal.

The inner double flange fold has an air gap between its flange portions and at least part of its transverse surfaces resiliently resting inside the outer double flange.

The folded flange connection comprises at least one continuous insulating layer in part between one double flange eversion and a second double flange eversion surrounding the first.

A method of producing at least partially seamed metal folded flanges on plastic pipes and / or pipe bend segments in a flange folding machine and / or folding machine / closing machine having a rotatably mounted shaping roller and a feed roller, displaceable in one plane, in which both rollers are driven by a motor and protrude from the machine table, according to the invention, that in the first step of this method, a double flange is made at the end of the first pipe, then in the second step, a flange with a larger internal diameter than the double flange formed at the end of another pipe to be joined is made, then, in the third step, the folded edge is placed over the double flange and then the protruding part of the folded edge is bent and clamped on the double flange in the butt manner, so that the double flange connection is tightly enclosed.

In the first step, the end of the first tube is put on a rotating first shaping roll fixed in an axial position on the machine table in circumferential contact between the inside of the tube and said roll, then in the second step, a second shaping roll similarly rotating in a tangential plane is brought into contact with the tip pipes on the outer side, thanks to which the latter rotates in a synchronous manner, then, in the third step, the second shaping roll is steplessly moved in a tangential plane by the width of the double curl to the first shaping roll, so that a continuous folded edge is formed at the end of the pipe, and in the fourth step, the lower feed roller moves further towards the shaping roll in the second plane located below the tangent plane by at least twice the thickness of the pipe material, the second lower roll retracts under the second shaping roller synchronously in the opposite direction, thereby closing the flange and forming a double flange.

PL 198 627 B1

Device for producing metal sealing folded flange connections at least partially sealed seam on plastic pipes and / or pipe bend segments, on a flange folding machine and / or folding machine / closing machine having a rotatingly mounted shaping roller and feed roller, staggered in one plane, where the upper rollers the shapers are motor driven and protrude from the machine table according to the invention, characterized by that the adjustable lower roller is in the form of a hollow shaft, and inside the hollow shaft is arranged a drive shaft supporting the shaping roller mounted in its axial position, furthermore the supply roller is in the form of a hollow shaft, and inside said hollow shaft is a drive shaft supporting the upper shaping roller, with whereby the feed roller and the shaping roller are placed on the sliders so that the displacement takes place in a synchronous manner, and further, both rollers are disposed on a slider similarly staggered to the axially mounted shaping roll and the displaceable shaping roll.

The slider is guided in linear ball bearings.

The sliders are guided linearly in the transverse guide plates.

Hydraulic cylinders are connected to the spools.

The spools are connected to the hydraulic unit in linear synchronization by means of hydraulic cylinders.

The drive shafts are connected to the hydraulic unit in circumferential synchronization by cardan shafts and hydraulic motors.

The metal seal in the form of a folded flange connection according to the invention can meet the high sealing requirements of today's practice.

The turned-over flange connection is also suitable for air-conditioning units in air-tightness class C without additional sealing measures and / or additional processing. Class C in relation to highly tightly sealed flanged connections (defined by the Committee of Producers of Ventilation and Drying Equipment of the Committee of Producers of "Ventilation and Drying Plants (EUROVENT)) corresponds to a maximum leakage of, for example, 0.01 m³air / second in the test area of ​​200 m² at a pressure of 1000 Pa.

The invention makes it possible to provide good quality turned flange connections in an economical manner and to use them in the most universal way, i.e. for pipes, pipe segments and pipe bends.

The folded flange connections according to the invention are achievable with conventional technology without the need for specialist training of operating personnel, and at least in appearance and stability correspond to known connections.

The folded flange connection forms an assembled seal inside the fold, in particular on the outer diameter of the double flange, due to the relatively large curl radius surrounding the second outer double flange. As a result, the springback of this connection is minimized. The metal seal is durable and only slightly insensitive to vibrations. The stiffening radius in the region of the largest outer diameter on the outer double fold is greater than the closed flange folded in a single way (with a so-called single edge). This prevents excessive protrusion of the bending point, which is unacceptable for material reasons, and hence a significant displacement of the material, also prevents hairline cracks and subsequent curl corrosion, which often occurs in existing ventilation devices.

The term "circumferentially continuous" means the presence of a joint sealing surface which rests on the mating member and which extends in a linear and concentric manner without interruption over the entire circumference of the folds.

When the folded flange connection is opened by a slit, unlike a single folded flange connection, it exhibits an almost perfect seal face contact with a tight fit over the entire inner double flange with respect to its shape.

The above-mentioned continuous connection of the sealing surfaces, mentioned above, is essential for the correct behavior of the seal in the joint, since, in addition to the actual closure, this forms at least one labyrinth connection with minimal leakage losses.

In contrast, it has proved advantageous if the double flange forms an air gap arranged inside, whereby a deliberate internal elastic action occurs.

PL 198 627 B1 fold over the second double fold. This ensures a durable metal seal even when operating under varying pressure.

Namely, in the case of non-clad pipes, an insulating polymer layer applied in a fluid state may be advantageous since there is no contact corrosion at the joint in the flange; the thin layer remaining after curing will additionally compensate for the sealing effect. Functionally, the insulation layer does not change the basic principle of the sealed seam generated during closure and generated by external forces, even if the metal contact surfaces are supplemented with thin intermediate layers or if the clad sheets are replaced and / or supplemented with an insulation layer.

An air gap that carries an intense external pinch action between parts of the collar as a result of its spring action is particularly advantageous. This improves the sealing due to the strong pressing of the contact surfaces and also compensates for thermal expansion and vibrations without increasing leakage.

The sealing can furthermore be improved by the inclusion of an additional insulating layer between the outer and inner turn.

The folded flange connection is made on a Gorelocker Beta 3 press brake from Spiro International SA, CH-3178 Boesingen (see Brochure 05.1998) using appropriate rollers.

This is done in the first step with a double flange flange at the end of the first pipe, in the second step with a flange edge with a larger inside diameter than the double flange formed on the end of another pipe to be joined, in the third step, in which the flange edge is placed over the double flange and then the protruding part of the flange is folded and clamped over the double flange in a butt fashion, whereby the double flange joint is tightly encircled.

In the device according to the invention, which is preferably used, the production of a double flange at the end of the first tube takes place in a first step, in which the end of the first tube is placed on a first rotating forming roll mounted in an axial position on the machine table in circumferential contact between the inside of the tube and said rollers, in the second step, the second shaping roller, similarly rotating, is brought in a tangent plane until it meets the pipe end on the outer side, whereby the latter rotates in conjunction, synchronously, in the third step, the second shaping roll is continuously adjusted in a tangent plane by the width double curl to the first shaping roller, thus creating a continuous, folded edge at the end of the pipe, in the fourth step, the lower feed roller moves further towards the shaping roller in a second plane located at a level lower than the tangential plane by at least twice the thickness of the pipe material, the second lower roller retracts under the second shaping roller synchronously in the opposite direction, thereby closing the rolled up edge and creating a double flange.

A device particularly suitable for producing a double flange flange is characterized in that the adjustable lower roller is made in the form of a hollow shaft and a drive shaft is placed inside the hollow shaft supporting a forming roll mounted in an axial position. The feed roller is made in the form of a hollow shaft. Inside this hollow shaft is a drive shaft that supports the upper forming roll. The feed roller and the forming roll are placed on sliders, so that the displacement takes place in a synchronous manner, and moreover, both rollers are placed on a slider similarly adjustable in relation to the axially mounted forming roll and the adjustable forming roll. This provides a particularly economical mode of operation.

The shaping roller and the lower supply roller located below are guided in a particularly precise and stable manner, thanks to their mounting in a slide provided with linear ball bearings.

Thanks to the use of transverse guide plates, it was very easy to move the next sliders lifting the similarly adjustable lower feed roller and the lower shaping roller.

The rectilinear shifts of the sliders are performed by hydraulic cylinders, which creates a very compact and advantageous structure of this device.

PL 198 627 B1

Another advantage of the device is the use of synchronous movement of the sliders, which is possible thanks to the hydraulic components.

The drive shafts of the driven rollers are driven in a very small space, using cardan shafts and hydraulic motors, which are fed from the central hydraulic system and set and regulated by means of known per se for circumferential synchronization, i.e. to obtain the same circumferential speed of the rollers .

The subject matter of the invention is shown in the examples of the drawing, in which Fig. 1 shows a typical connection in ventilation technology: two helical pipes arranged at right angles to each other are connected with each other by means of segmented bends and folded flange connections; Fig. 2 shows the folded flange connection according to Fig. 1, an enlarged fragment; Figures 3 to 6 show the individual steps of the method for producing the integral double flange flange according to Figure 2; fig. 7 - joining the folded flange connection; Fig. 8 is an assembly of the folded flange connection according to Fig. 7 by folding the folded edge; Fig. 9 is a partial sectional view of a device for producing a double flange flange; Fig. 10 is a left-hand drive shaft section in orthogonal view; Fig. 11 is a top view of the device of Fig. 9.

Fig. 1 shows tubes coiled from clad sheets s1 and s2 known as "spiral tubes" which are connected to each other by segmented bends s2 to s5. The segmented bends s2 to s5 are connected to the pipes s1 and s2 by traditional detachable connections V. The joining bends s2 to s5 have rolled edges W to serve as reinforcement and also as stops. The folded flange connections according to the invention are designated A; the center line of the pipe connection is marked m, which corresponds to the neutral line.

The folded flange connection A is enlarged in Fig. 2. Shown are the middle small bends s3 and s4 with the first pipe end X and the second pipe end Y. The transition elements were made in the form of offsets 5. The end X of the pipe ended with a double flanged turn 1 with flange parts 1a and 1b jointly forming the rim flange. An air gap 3 is formed between the flange portions 1a and 1b, which forms i.a. expansion joint for segment s3 and at the same time allows springback on the outer part surrounding the double fold 2.

The surrounding double fold 2 seams the outer region of the flange portions 1a and 2b and the fold 1c outside. Even though the sheet in the double fold is irregularly shaped, the illustrated spring joint gives points of contact more or less concentric on portions 1a to 1c, forming a labyrinth seal.

The connection by the inner flange, i.e. the double flange 1 with the surrounding double flange 2, is made in a manner known per se on a joining folding machine, e.g. of the Gorelocker Beta 3 type.

Figures 3 to 6 show the production of the folded flange connection. The molded part or pipe segment to be reworked is marked with 6 and is based on a bearing surface 29.

According to this method, as shown in Fig. 3, in a first operation, the tubular end of the segment 6 turns with the inside outward on a rotating forming roll 20 and a bottom roll 21 located below which is shaped like a hollow shaft and has a corresponding lower central recess H. which is much larger than needed to drive roll 22 without contact. The adjacent shaping roll 10 and the lower feed roll 11 are held in a rest position.

As shown in Fig. 4, both rollers 10 and 11 were brought against the molded part 6 by a motion a_about until the contact of the shaping roll 10 which has simultaneously started to rotate. Due to the friction of the outer circumference of the roller 10 and the molded part 6, the molded part starts to rotate. Mutually parallel tangent surfaces E1 and E2 are shown representing the possible displacement of the rollers 10 and 11.

As a result of the continuous stepless advance of the rotating shaping roller 11 up to the end of the movement a1, a folded edge 4 is formed, protruding around the entire circumference of the underside of the formed part 6. See Fig. 5.

As the molded part 6 continues to rotate as shown in Fig. 6, the lower supply roller 11 similarly performs the movement a₂but in the E plane₂thereby creating a double curl on the molded portion 6. This movement is possible because the rollers 11 and 21 form recesses H. The synchronization of the movement of the two rollers 11 and 21 leads to the formation of an exact curl shape without flattening the flange portion or changing the position of the rollers.

PL 198 627 B1

The molded part 6 with the folded flange connection can be removed after the rollers have returned to the initial position according to Fig. 3 and the next operation can be started.

The assembly of a flange connection is shown in Figures 7 and 8 using the previous reference numbers. It should be noted that by folding the lip 4 there has been a reduction of the rather large air gap 3 of Fig. 7 to the small air gap 3 'of Fig. 8. This explains the effect of constant springback present in practice and thus the seal within the flanged flange joint.

The method for producing the inner double flap 1 described with reference to Figs. 3 to 6 is used in the device illustrated in Figs. 9 to 11.

As shown in Fig. 9, the movable shaping rollers 10 and the feed roller 11 are mounted in a slider 37 which slides in a similar manner. The roller 10 is mounted on the drive shaft 12 in an axial mounting 22 made as a threaded connection with a key. In a similar manner, the underside of the drive shaft 12 has a key 14 and communicates with the hydraulic motor 26 via the cardan shaft 24. The shaft 12 is rotatably mounted in the slider 37 in roller bearings 16a and 16b, and the slider is driven by the piston rod 31 'of the hydraulic cylinder 31. There is also a slightly smaller hydraulic cylinder 30 fixed with bolts 35, connected to the piston rods 30' by a pin 33 located in the slider 38, sliding in similar way. In the slide 38 there are mounted roller bearings 18a and 18b concentrically mounted on the shaft 12, the inner rings of which are connected to the feed roller 38. A cylindrical recess 39 is provided between the shaft 12 and the bore in the feed roller 31. The housing of the roller bearings 18a and 18b is indicated by 18 '; the play required for free rotation of the rollers 10 and 11 is indicated by L.

The opposite pair of rollers, namely the shaping roll 20 and the lower roll 21, are similarly made, and there is play L between these rollers. Unlike the previous example, a shaping roll plate 44 is used which is attached to the machine, i.e., is stationary. The roller 21 is mounted on the drive shaft 13 by an axial mounting 23 made as a threaded connection with a key. The drive shaft 13 likewise has a key 14, and the hydraulic motor 27 is connected below it by means of a cardan shaft 25. Shaft 13 is rotatably connected to plate 44 in roller bearings 17a and 17b. The hydraulic cylinder 32 is fastened with screws 36, and the piston rods 32 are connected by a pin 34 embedded in the sliding slide 45. In the slide 45 there are roller bearings 19a and 19b concentrically mounted on the shaft 13, the inner bearing rings are placed on the sliding roller 21 underneath the hollow shaft. The mounting of the roller bearings 19a, 19b is shown as 19 '; the cylindrical airspace that exists here is marked with 40. The molded part 6 to be converted rests on a support surface that is movable on the machine table 29.

The hydraulic components are supplied from the central hydraulic unit 50 located in the machine body and connected by hydraulic conduits 49 with the control system and driving elements.

The AA section of the shaft 12 marked in Fig. 9 is shown in Fig. 10 showing the parts described above and additionally two linear ball bearings 41, 42, sleeves 41 'and 42' mounted in the slide 37. The mounting frame 46 of the machine body is visible from the side, and welding seams 47.

Threaded holes 28 are provided in the slide slide 37 to accommodate the transverse plates and guides 38 'of slide 38 bolted above and similarly slideable. The sliding part 18 'is also a holder for roller bearings 18a, 18b. The slide 45 shown in Fig. 9 is made in a similar manner.

The individual parts are again visible in Fig. 11 in plan view, which also shows the previously unmarked guide plates 45 'and additionally the adjustment screws 48 for limiting the movement and adjusting the offset of the sliders 38, 45.

The method of operation of the apparatus for the cost-effective production of high-quality and reproducible double flange folds is easily reproduced according to Figs. 3 to 6 and the description given. Further details of the design of the device correspond to that of the machine according to EP-A1-0 998 997.

The easiest way to adjust the spacing between the rollers 10, 11 and 20, 21 is by means of intermediate rings (not shown), which changes the clearance L accordingly. This allows the tough and elastic behavior of the double flange to be easily varied and optimized, which at the same time it determines the service life of the rollers and the wear exerted on the molded part 6.

In practical testing of the folded flange joints according to the invention, the leakage rate was measured and the result was at least 20% better than with the Eurovent, KlaPL 198 627 B1 sa C. The double folds produced and tested had a typical fold width of 4.0 to 12.0 mm with measurements on the inner double fold.

The precondition for this, however, is the reliable production of the folds, which is reproducible with the device according to the present invention.

Such high-quality flanged connections are particularly important in processing technology and for clean rooms, etc., where transient leaks can lead to all kinds of hazards. Again, the invention allows low-cost pipe segments to be used in conjunction with the well-known spiral tubes (spiral tubing) instead of the generally used costly welded tubes with corresponding joints and / or joints sealed with flexible liners. In addition, the necessary maintenance of such units is reduced as the metal seals are generally not subject to wear.

In an aspect of development, the device can be automated, for example by producing folded flange connections with memorized all machine settings and control parameters, which can then be used in mass production. For this purpose, usually known "training programs" in combination with measuring sensors etc. can be used.