EP0178236B1 - Apparatus for making corrugated tubes for heat exchangers, and similar applications - Google Patents

Abstract

For manufacturing tubes of the "corrugated" type, i.e. comprising at least one deformation of helicoidal profile, the smooth tube (28) is displaced axially inside a fixed sheath (7) about which rotates a sleeve (4) fixed to a head forming support for at least one radially mobile "corrugating" knurl; the displacement of the knurl is effected by a cam (25-26) which surrounds said head and which is actuated by a jack (13-14). Opposite this "corrugating" knurl there is provided a cutting knurl which cuts the tube at the end of the "corrugation" operation. The number of the "corrugating" knurls may vary.

Description

It is known that for the production of temperature exchangers and other devices of the same kind, tubes of the type have been proposed having, between two connecting sleeves provided smooth, a series of deformations with a helical profile, obtained by pushing back so as to affect the inner wall as the outer wall. Studies and measurements carried out on this type of tube have effectively demonstrated that the pressure losses and turbulence caused by "corrugations" on the fluid circuit very significantly improved the heat exchange coefficient.

However, the development of the use of these tubes has been slowed down due to production difficulties, the machines proposed to date (see for example FR-A-1 431 562) being far from satisfactory in practice, and c 'is to this drawback that the present invention intends mainly to remedy, and this using a manufacturing machine with high production rate and low maintenance cost.

The object of the invention is to make it possible to obtain “corrugated” tubes of any desired length, having at their ends (and even at one or more points along their length) smooth parts capable of facilitating connection operations and fixing. in place.

• Fig. 1 est une vue de côté avec arrachements montrant de manière schématique l'agencement général d'une machine de «repoussage» suivant l'invention.
• Fig. 2 en est une coupe transversale suivant le plan indiqué en II-II en fig. 1.
• Fig. 3 est une coupe axiale, à plus grande échelle, de la tête tournante et de la came de commande.
• Fig. 4 illustre en perspective, à l'état démonté, le montage du dé porte-molette de «repoussage» et son mode de réglage.
• Fig. 5 et 6 sont des coupes axiales analogues à celle de fig. 3, mais correspondant à deux autres positions.
• Fig. 7 est une vue de côté analogue à celle de fig. 1, montrant une machine équipée de trois molettes de repoussage».
• Fig. 8 et 9 sont des coupes transversales à plus grande échelle suivant les plans indiquée en VIII-Vill et IX-IX en fig. 7.

The appended drawing, given by way of example, will allow a better understanding of the invention, the characteristics which it presents and the advantages which it is capable of providing:

• Fig. 1 is a side view with cutaway diagrammatically showing the general arrangement of a "pushing back" machine according to the invention.
• Fig. 2 is a cross section along the plane indicated in II-II in FIG. 1.
• Fig. 3 is an axial section, on a larger scale, of the rotating head and the control cam.
• Fig. 4 illustrates in perspective, in the disassembled state, the mounting of the “push-back” wheel holder die and its adjustment mode.
• Fig. 5 and 6 are axial sections similar to that of FIG. 3, but corresponding to two other positions.
• Fig. 7 is a side view similar to that of FIG. 1, showing a machine equipped with three embossing knobs ”.
• Fig. 8 and 9 are cross sections on a larger scale according to the plans indicated in VIII-Vill and IX-IX in fig. 7.

The fixed frame of the machine shown in fig. 1 to 6 is formed by a sole 1 secured to two vertical flanges 2 drilled horizontally to allow, by means of the interposition of bearings 3, the mounting of a rotating sleeve 4. In the vicinity of one of its ends, this sleeve 4 carries a drive pulley 5 which a belt 6 connects to any motor, not shown, advantageously provided at variable speed. Inside the sleeve 4 is axially engaged a fixed sheath 7 whose end disposed in line with the pulley 6 is supported by a foot 8 made integral with the sole 1; it will be observed that the outlet of this sheath 7 is oriented along the axis of a device 9, of the roller type, intended to straighten the tube to be worked and to animate it with a continuous longitudinal movement, itself advantageously provided with adjustable speed.

As more particularly shown in fig. 1 and 2, the flanges 2 of the fixed frame 1-2 support a horizontal console 10 on the free edge of which are articulated in 11 two pivoting arms 12 whose lower ends pass through the sole 1 through an opening 1 a for s hitch to a yoke 1 2a. The latter is fixed at the end of the movable member 13 of a pneumatic or hydraulic cylinder 14, of the double-acting type. It will be understood that, depending on whether the jack 14 is actuated by extension or by contraction, it controls the arms 12 to cause them to affect one or the other of the two oblique orientations indicated at 12 'and 12 "in FIG. 1 .

As illustrated in fig. 3, the end of the sleeve 4 opposite to that which carries the pulley 5 is made integral, for example by means of threaded tie rods not shown, with a rotating head 15 disposed immediately in front of a bearing 16 interposed between the fixed sleeve 7 and said sleeve 4. This head 15 is pierced with two radial bores (referenced 15a in fig. 4), oriented opposite one another and inside each of which is housed a guide cylindrical 17; the upper part of each guide 17 is provided with an overflowing flange 17a fixed to the rotating head 15 by means of screws 18.

The opening 17 _Q. (fig. 4) made axially through each guide 17 is established at a polygonal profile (rectangular in the envisaged exemplary embodiment), and inside this opening 17b is slidably engaged a die 19. The latter is profiled in the manner of a yoke open downwards, in order to carry a horizontal axis 20 forming a support for a wheel referenced 21 for one of the two dice 19, 22 for the other. Each die 19 is provided upwards with an overflowing flange 19a to which are fixed vertical studs 23 (only one of which has been shown in FIGS. 3 and 4 so as not to overload the drawing unnecessarily) turned downwards; each stud 23 is engaged inside a blind bore 1 7c of the corresponding guide 17, a spring 24 tending to elastically push the collar 1 9a and the die 19 upwards.

The wheel referenced 21 (arranged in the upper part of FIGS. 2 and 3) is profiled to repel the metal, and it will hereinafter be referred to as the "pushing back" wheel, while the wheel 22 turned downwards in the above figures is profiled to cut the tube. It will also be observed that if the screws 18 which secure the guide 17 associated with the die 19 fitted with the cutting wheel 22 pass through the holes in the flange 17a practically without play before being screwed into the threads of the head 15, it is not the same for those which retain the opposite guide forming a support for the "pushing" mold 21; as illustrated in fig. 4, these screws 18 are introduced into slots 17d with a profile in an arc of a circle concentric with the axis of the opening 17b, so as to allow the orientation of the envisaged guide 17 and of the knob 21 to be adjusted relative to the axis of the head 15.

Above its flange 19a each die 19 is secured to a pusher or axial finger 19b with a profile semi-spherical exterior, suitable for being actuated by a cam formed by the assembly of two rings 25 and 26 which surround the rotating head 15 to which they are linked by the two fingers 19b. To this end, the outer wall of each of the two rings 25 and 26 is hollowed out with two longitudinal grooves 25a and 25b, respectively 26a and 26b, diametrically opposite to receive the two fingers 19b, but while the bottom of the groove 25a, 26a is oriented parallel to the axis of the cam 25-26, that of the groove 25b-26b is oriented obliquely to form an actuating ramp for the corresponding die 19. It will also be noted that the arrangement of the four grooves or ramps indicated above is reversed, in the sense that once the rings are mounted in place, the ramps 25b and 26b have opposite obliquities.

One of the rings 25 or 26 (the ring 26 in the embodiment considered) is hollowed out on its periphery with an annular depression 26c intended to form a track for two opposite rollers 27 (fig. 1 and 2) carried by the pivoting arms 12 and it is understood that the control of the jack 14 ensures the axial displacement of the cam 25-26 despite the rotational movement imparted to it by the head 15.

The operation and mode of use of the machine described below follow from the foregoing explanations and are easily understood.

When the machine is put into operation, the cam 25-26 is in the middle position illustrated in fig. 1 and 3, in that the fingers 1 9b of the two opposite dice 19 are engaged in the straight bottom grooves 25a and 26a. The speed of advance imparted to the smooth tube 28 by the device 9 was adjusted as a function of the speed of rotation of the sleeve 4 and of the angle of obliquity conferred on the "pushing" wheel 21.

The smooth tube 28 penetrates axially into the fixed sheath 7 and passes through an internal end piece 29 (FIG. 3) mounted at the downstream end of the latter. The end of this tube passes in line with the knobs 21 and 22 to be introduced into an outlet end piece 30 carried by an upright 31 (fig. 1) secured to the sole 1. When the length of the end of this tube which has exceeded the transverse plane defined by the two knobs 21 and 22 corresponds to the desired length for the smooth connection cuff, the operator controls the jack 14 to the extension, in order to bring the pivoting arms 12 to the orientation 12 'of fig. 1; this change in orientation has the effect of moving the cam 25-26 which therefore affects the position illustrated in FIG. 5.

Under these conditions, the finger 19b of the die 19 which carries the “pushing back” wheel 21 is engaged in the ramp 26b, so that it is pushed radially inward with said die against the elastic reaction. return springs 24. As shown, the knob 21 comes to bear against the wall of the tube 28 which it pushes inwards, generating on the latter a helical thread or "corrugation", so that said tube penetrates into the outlet nozzle 31 in the "corrugated" state (reference 28).

It will be noted that the axial displacement of the cam 25-26 on the other hand has not affected the position of the die 19 which carries the cutting wheel 22, since the finger 19b of said die remains in the groove with a straight bottom 26a.

On the other hand, things will be reversed when the jack 14 is again ordered by the operator at the end of "corrugation". Actually, the control of this jack to the contraction brings the pivoting arms 12 to the oblique position 12 "of fig. 1, corresponding to the situation illustrated in fig. 6. As a result of axial displacement of the cam 25-26, the die 19 which carries the wheel 21 is pushed radially outwards by the springs 24, its finger 19b coming to engage in the straight bottom groove 25a; the "pushing back" wheel is thus moved away from the tube 28. On the other hand, the oblique bottom groove or ramp 25b, by action against the finger 19b of the die 19 which carries the wheel 22, pushes said die radially inwards, so that this wheel 22 crosses the tube transversely during work.

Obviously, the transition from position 12 '(fig. 5) to that 12 "(fig. 6) takes place in two stages, in the sense that when the length of" corrugated "tube 28 reaches the desired value, l The operator controls the jack 14 to bring the cam 25-26 to the middle position of Fig. 3, the "corrugation" action ceases, but the tube 28 continues to advance. When the desired length for the smooth cuff is itself even obtained, the operator stops the device 9 to immobilize the tube 28 axially, and he again actuates the jack 14 to ensure the cutting of said tube by means of radial displacement of the wheel 22.

The machine is then ready to make a new length of "corrugated" tube.

Fig. 7 to 9 schematically illustrate the general arrangement of a "corrugation" machine at a very high production rate, capable of printing on the tube three helical threads oriented at 120 ° relative to each other. This machine comprises a toothed wheel 32 connected by a chain 33 to an adjustable speed motor (not shown) and keyed onto a horizontal sleeve 34 suitably supported for rotation by the general frame. Opposite the straightening and advancing device (not visible in fig. 7), this sleeve 34 is secured to a rotating head 35 which penetrates inside an actuating cam 36 connected by rods longitudinal 37a to a rotating disc 37 linked axially to a transverse flange 38; the latter, provided with lateral guides 39 which immobilize it angularly, is fixed to the movable member 40 of a control jack 41, so that the contraction or extension thereof modifies the position of the cam 36 relative to the rotating head 35, as in the case of the embodiment according to FIG. 1 to 6.

The head 35 is hollowed out with three radial bores 35a (FIG. 8) oriented at 120 ° from one another and inside each of which is mounted a cylindrical die 42 forming a support for a "pushing back" knob 43. A l 'opposite of its wheel 43, each die 42 is assembled by a screw 44 to an actuating finger 45, the outer part of which is established in a dovetail profile in order to cooperate with a groove with corresponding profile 46a formed in one, referenced 46, of the parts which constitute the cam 36. As illustrated in FIG. 7, the bottom of the groove 46a is oriented obliquely to act radially in the manner of a ramp on the finger 45 which is engaged.

It should be noted that the operation of the screw 44 which assembles each die 42 to its finger 45 makes it possible to modify the orientation of said die inside its bore 35a and thus to adjust that of the corresponding wheel 43 relative to the axis of the tube 28 to be “corrugated”. A vernier scale 45_a, printed on the periphery of each finger 45 and cooperating with a mark provided thereon, facilitates the abovementioned adjustment.

In a transverse plane offset axially on the rotating head 35 with respect to that defined by the aforementioned bores 35a, two cylindrical bores 35b (fig. 9) diametrically opposite one another have been provided in this head. In one of these bores 35b is housed a die 47 whose end facing the axis of the head 35 is equipped with a cutting wheel 48, while the opposite end with a dovetail profile is engaged in a groove 46b made in the part 46 of the head 35, the bottom of said groove being oriented obliquely, parallel to the bottom of each groove 46a, as visible in FIG. 7. In the opposite bore 35b is mounted a support 49 rigidly fixed to the part 35.

The general operation is identical to that explained in the embodiment according to fig. 1 to 6. The smooth tube 28 (FIG. 7) is moved axially continuously so as to penetrate into a fixed sleeve 50 which is disposed inside the flange 38 and the rotating sleeve 34, and penetrates into the head 35, driven in a continuous rotational movement as a result of its connection with the aforementioned sleeve. The longitudinal displacement of the cam 36 (from left to right in FIG. 7), under the effect of the command to extend the jack 40-41, causes the three fingers 45 to be actuated simultaneously and the corresponding radial displacement of the dice 42 which carry the wheels 43, so that the latter push back the wall of the tube 28 which is thus "corrugated".

The above-mentioned movement of the cam 35 on the other hand has caused the radial movement of the die 47, so that the thumb wheel 48 cannot come into contact with the tube 28 '. It is only at the end of the "corrugation" operation and after actuating the jack 40-41 on contact that the axial displacement of the cam 36 ensures, at the same time as the radial withdrawal of the dice 42 which carry the wheels 43, the radial advance of the die 47 and the wheel 48, the latter thereby cutting the tube 28 ′, of course after the axial advance of the latter has stopped.

It will be noted that the arrangement of the machine according to the invention lends itself particularly well to fully automatic actuation, with prior display of the length of the “corrupted” part and of the smooth end cuffs of each tube to be produced. It is further understood that the number of "push-back" knobs can vary to a very large extent, depending in particular on the nature of the "corrugated" tubes to be manufactured and the desired production rate. It will also be understood that in certain cases the radial displacement of the rollers is capable of being effected by means of an actuating cam with angular displacement and not rectilinear as mentioned above.

The adjustment of the orientation of the "pushing" knobs, together with the adjustment of the tube advance and head rotation speeds, allows the realization of "corrugations" having any helix angle; by means of angular immobilization of the head one can even execute longitudinal "corrugations".

Claims (2)

1. Apparatus for making corrugated tubes for heat exchangers, and similar applications, of the kind comprising at least one bulging wheel (21) movable radially on a rotating hoad (15) and driven in order to apply itself forcibly against the wall of the smooth tube that is to be bulged which is kept angularly fixed whilst being axially displaced relative to the aforesaid head (15), characterised in that it comprises futhermore at least one sectioning cutting-wheel (22, 48) arranged relative to the bulging wheel (21, 43) in such a way that the radial drive of the latter in the opposite direction to the one corresponding to the bulging effects simultaneously the placing of the sectioning cutting-wheel (22, 48) in the working position and by application by force the transverse cutting of the tube (28) at the end of the bulging operation.

2. Apparatus according to claim 1, characterised in that the bulging (21, 43) and cutting (22, 48) wheels are carried by bearing-bushes (19, 47) which shift radially in the rotating head (15, 35) under the effect of two oblique slopes (25b and 26b, 46a and 46bJ orientated parallel to one another in the inner wall of an actuating cam (25-26, 36) which surrounds the said head, these slopes being offset axially relative to one another in order to act selectively on the one or the other of the two aforesaid bearing-bushes by way of displacement of the said cam.

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