KR900000040B1 - Annealing Apparatus and Method - Google Patents

Abstract

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Description

Annealing Apparatus and Method

1 shows a preferred embodiment of an annealing device using resistance heating with respect to the length of a tube driven in both directions.

2 is a side view of the apparatus shown in FIG.

3 shows a modified embodiment of the annealing chamber using induction heating techniques.

4 shows a modified embodiment of the annealing chamber using a radiant gas heating technique.

FIG. 5 is a sectional view along line 5-5 of FIG.

* Explanation of symbols for main parts of the drawings

28: carriage 30: tube

32: annealing chamber 34: quenching chamber

52, 52 ', 54, 54': Clamp member 60: Air cylinder

72: power track assembly 98: counter

FIELD OF THE INVENTION The present invention relates to annealing elongated members such as tubes and similar rods or wires, and more particularly to being able to anneal only the necessary portions of the elongated member. Elongated members are used in heat exchangers as straight length fin tubes, which have been machined to short lengths cut from some straight portions of large coils which have been previously annealed. Here, the short cut lengths have long mandrels fitted therein, and then are placed in the snooping device, where the flattening member is brought into contact with the tube and the tube so that a free face and an end can be provided. It is possible to move selectively in.

When the free parts are in an annealed state, the tube can be easily assembled into the heat exchanger's baffle or tube sheet header by internal expansion techniques. Conventional techniques for annealing tubes include batch and continuous methods. In a staged approach, the whole coil or individual tubes have to stay in the furnace for longer. This method is very expensive and requires a lot of time. It also consumes a great deal of energy. The continuous method is a further refinement than the stepwise method, for example the device known from Herren et al Patent No. 3,518,405. In this device the tubes are partially bent around the electrode wheels which are separated from each other which causes the part of the tube between the wheels to heat up. The electrode wheel is made of graphite which is consumed relatively quickly, which requires maintenance costs and there is a downtime while changing the electrodes. As another example, the device known from Jude Patent No. 4,309,887 continuously heats the entire tube by induction heating and the device known from Patent No. 3,708,354 employs the continuous annealing method.

It is a first object of the present invention to provide an annealing apparatus capable of continuously operating at high speed a fining operation for making several short length tubes in a large coil. It also provides a relatively compact and simple structure that can be operated for a long time with little maintenance and is energy efficient.

These and other objects and effects are achieved by the apparatus and method according to the invention capable of selective or spot annealing at least at a speed sufficient for downstream firing operations along the length of the continuously moving tube. . However, the device can also be used for spot annealing flat tubes, fires or rods apart from downstream directional firing operations. The apparatus of the present invention includes an annealing chamber mounted to a reciprocating carriage moving in the direction of a tube or other workpiece. The annealing chamber includes a pair of clamps engaged with the tubes that are spaced from one another and are automatically operated, the clamps engaging the tubes. The attached camber and carriage move downstream with the tube during the limited time the clamp and the moving tube engage. Thus, spot annealing occurs during the time the carriage moves. As the clamp is released, the air cylinder or other means quickly returns the carriage upstream to its initial position. The quenching chamber is preferably placed directly below the anneal chamber so that the portion of the annealed tube can be quickly cooled as the carriage returns upstream. Filling the annealing chamber with an inert gas, such as nitrogen gas, can prevent the tube from oxidizing and / or discoloring during annealing, while quenching is to prevent oxidation and / or discoloration after annealing. In most cases, the surface defects described above have no effect on the performance of the tube unless a spot annealed tube is used. However, it is very beneficial to quench and inject inert gas as clean and shiny tubes can be more in line with the buyer's preferences than those that are not. In order to give the annealed tube cross-section good grain size or hardness characteristics, the annealing time and temperature should be selectively adjusted during spot annealing. Preferably, the signal from a small computer is controlled by an electrical relay. The computer receives a signal that is counted by a wheel of a counter operated by a wheel encoder that rotates as the tube moves. The above elements typically anneal only the portions of the tube that remain undisturbed in the downstream firing operation. In a preferred embodiment annealing is done by resistance heating through the clamps, where each element acts to allow the clamps to contact the tube for short time intervals before and after the residue is supplied to prevent arcing. In two modified examples, annealing is achieved by replacing the resistive heating annealing of the preferred embodiment with induction heating annealing and radiant gas annealing.

Referring to FIG. 1, the annealing device 10 includes a pedestal 12. The pedestal 12 is composed of an upper fixed support plate 14 and a lower fixed support plate 16. The first of the two pairs of support blocks 20 supports the first guide rail 22, while the second supports the second guide rail 22 ′.

The support block 20 is attached to the upper fixed support plate 14 by any suitable means such as fasteners. A plurality of spaced guide blocks 24 mounted on the bottom surface of the carriage 28, that is, the carriage 28, are slidably mounted to the guide rails 22, 22 '. The annealing chamber 32 covered by the top plate 33 is mounted upstream of the arrow direction in which the tube 30 travels. The quenching camber 34 covered with the carver member 35 is located immediately downstream of the annealing chamber 32.

Carriage 28, including annealing and quenching chambers 32, 34, is provided with guide block 24 and guide rails 22, 22 'to reciprocate axially in the region. Movement downstream from the position shown in FIG. 1 is accomplished by fixing the carriage relative to the moving tube 30 as described below. Movement in the upstream direction is provided by the piston shaft 38 connected to the carriage by the support block 39 at its upstream or extended end and at the downstream end of the movable piston (not shown) of the air cylinder 40. Is done by The return movement of the piston shaft 38 and the carriage 28 is made by introducing air into the cylinder 40 through the hose 41 and discharged through the hose 42. In the downstream direction, each of the hoses 41 and 42 is preferably valve-controlled in the exhaust mode so as not to interfere with the downstream movement of the carriage. Since the carriage can be returned upstream by the air cylinder 40 at a very high speed, the hydraulic spring member 44 is preferably provided as cushion.

The forward drive tube 30 described above provides a force to advance the carriage 28 in the downstream direction, which is fixed clamp members 52 and 52 'when the piston shaft 58 of the air cylinder 60 is actuated. A pair of fixed clamp members 52, 52 ′ and movable clamp members 54, 54 ′ attached to the movable clamp plate 56 to secure the tube 30 with respect to the tube 30.

When resistance annealing is used, the fixed clamp members 52 and 52 'each have a conductive jaw of different potential so that a portion of the tube fixed therebetween is resistively heated. In addition, the fixed clamp members 52 and 52 'are attached to the bracket 61 which electrically insulates the member from the housing portion of the annealing chamber 32. Moreover, the insulating plate 62 insulates each of the movable clamp members 54 and 54 'and these members and the movable clamp plate 56 to which they are attached.

Current flows through the water-cooled electric table 66 connected to the transformer 68 at opposite ends to the fixed clamp members 52, 52 '. The cable 66 is a very thick line that is flexible and preferably moves along the carriage 28 by a power track assembly 72 securely attached to the carriage 28 at the top and to the lower fixed support plate 16 at the bottom. Is supported. The power track assembly 72 has a capacity to support a plurality of cable-like members, including hoses 74 and 75 for supplying air to the air cylinder 60.

Inert gas (nitrogen) is supplied from the nitrogen tank 76 to the interior space of the annealing chamber 32 and the quenching chamber 34. Gas is supplied through an appropriate valve (not shown) to the inlet tube 80 of the annealing chamber and the inlet tube 82 of the quenching chamber, respectively. Inert gas is present in both chambers up to the openings 32 'and 34' at the end through which the tube 30 passes. The quenching chamber 34 includes a coolant inlet nozzle 86. The shape of the nozzle is such that water can directly contact all outer peripheral surfaces of the tube. This cooling water exits the quenching chamber through the discharge passage 88.

The tube 30 is released from the annealing device 10 by the funnel-shaped discharge guide 92. The device of the present invention does not have a means for adjusting the tube downstream, but may include means for rewinding or shortening the tube or simple means for finishing the spot annealed tube.

The tube 30 is driven in a positive direction, ie, in the machining direction, when entering the annealing chamber 32 through the opening 32 '. The tube passes through a series of straightening rollers 94 at least partially powered with a good number of coils (not shown) wound. The straight tube passes through the wheel encoder means 96 in which the wheel rotates as the tube advances to generate a counter pulse that indicates tube displacement in the counter 98. The control panel 100 includes suitable adjusting means for manually operating the annealing device 10. Preferably, however, counter pulses generated at counter 98 in accordance with tube displacement are input to computer means and programmed to energize fixed air cylinder 60, return air cylinder 40 and clamp in accordance with counter pulses. . In order to prevent arcing during resistance annealing operations, the power is not fixed until the cylinder 60 is actuated to press the movable clamp members 54, 54 'against the tubes. It is told. Likewise, power to the clamping member is cut off before the clamping air cylinder 60 is released.

The annealing apparatus of the present invention may use other methods such as induction heating annealing or radiant gas annealing, in addition to resistance annealing, and the power inpot, the moving time and the annealing temperature of the tube and the carriage while the power is applied to various requirements. Can be designed to change accordingly. In the case of resistance annealing, the power can be varied by appropriately selecting a transformer 68 with an adjustment tab. For example, a suitable annealing temperature for a copper tube is 649 ° C., which provides an annealed area between the clamp having a hardness of 57-60 of particle size 15 and Rockwell 15T at that temperature. Obviously, when performing resistance annealing at a specific tube speed, the power to be applied should be sufficient to produce the required tube temperature, depending on the tube density, the distance between the clamping members 52, 52 ', and the heating time. Change. Since the heating time is limited by the traveling speed of the tube and the maximum moving capacity of the carriage 28, an experiment is found to find a power tap that can obtain the required temperature in the range of possible carriage movements when operating the device for a particular tube. It is relatively straightforward to provide a time-varying time to power up to the correct temperature. Quenching water flows in continuously, changing the flow volume through the nozzle 86. Similarly, nitrogen gas is continuously introduced while varying the flow rate through the pipes 80 and 82.

The following describes an embodiment of spot annealing, that is, an embodiment in which resistance annealing is performed by allowing a current to flow through the fixed clamp members 52, 52 'through a portion of the tube 30 engaged between the clamps. Other methods could be replaced by resistive heating techniques with little change to the apparatus shown in FIG. 1 and FIG.

3 shows an induction heating annealing chamber 132, which includes a pair of fixed clamp members 152, 152 ′, a pair of movable clamp members 154, 154 ′ and a water cooled induction heating coil. (188) is included. The one clamp is engaged with the moving tube 130 and the annealing chamber and carriage together with the tube during annealing via a water cooled induction heating coil 188 surrounding a portion of the tube engaged with the annealing clamp. Move downstream To ensure safety during operation and to protect the material of the tube, interrupt the current before releasing the clamp and engage the clamp before applying an induction field to the tube. In other annealing methods (induction heating annealing, radiation gas annealing), the structure of the annealing chamber and the movement control operation of the carriage are very similar to those described in resistance heating annealing. The induction heating coil consists of a hollow tube (188 ') connected to the cooling water supply and discharge tubes (190, 190') and a solid bar (188 ') through which a spiral wound current is connected to the electrical cable (166). It is shown to be.

4 and 5 illustrate an arrangement of the radiant gas annealing chamber 232 that uses natural gas to perform spot annealing on the tube 230. The chamber 232 includes a pair of fixed clamp members 252 and 252 ', a pair of movable clamp members 254 and 254' and a water-cooled radiant heating chamber 291 positioned longitudinally between the tube clamps. The housing has a longitudinal row of spark plug gas burners 292 mounted about its internal reflecting wall surface 293.

As in the annealing technique described above, the clamps engage the moving tube 230 and allow the annealing chamber and carriage to advance downstream with the tube while annealing is in the tube burner housing. In general, all other structures of the annealing chamber and the control operation of the carriage are similar to those described in resistance spot annealing. The gas burner 292 is a mixed burner commercially available from the North American Manufacturing Co., Cleveland, Ohio. It is preferably mounted to the gas receiving manifold 294 to extend through the outer wall of the radiant heating chamber 291 and the inner reflecting wall surface 293. Superheat inside the wall of the radiant heating chamber 291 is discharged by the circulating cooling water entering the pipe 295 and exiting the pipe 296.

In some cases, a hose may be attached to the interior of the radiant heating chamber 291 to provide a flame passage.

Claims (22)

An apparatus for selectively annealing a portion of a tube while moving a metal tube (30), comprising: a pedestal (12) comprising guide rails (22, 22 '); A carriage 28 mounted to reciprocate on the guide rail; A pair of clamp members 52, 52 spaced apart from each other by the axial length of the annealing chamber 32 mounted to the carriage 28 and the tube portion mounted and annealed at the upper end of the annealing chamber. ', 54,54'); Means (58) for periodically actuating the spaced clamp member to engage at least one separation site of the tube passing through the annealing chamber and to allow the carriage and annealing chamber to be moved by movement of the tube (58). 60); Means (58,60) for heating and annealing at least one separation of the tube and for releasing the clamp member while placed in the annealing chamber and the tube is engaged by the clamp member; And an means (38,40) for returning said carriage to an upstream end of said guide rail (22, 22 '). 2. An annealing device according to claim 1, wherein the annealing chamber comprises inlet means (80) for receiving an inert gas. A quenching chamber according to claim 1, further comprising a quenching chamber located immediately downstream of said annealing chamber and containing fluid inlet nozzle means 86 for rapidly cooling the portion of the heated tube with fluid after the clamp member is released. Annealing device, characterized in that provided. 4. The annealing device according to claim 3, wherein the quenching chamber (34) comprises an inlet port (82) for receiving an inert gas. 4. The annealing device according to claim 3, wherein the fluid inlet nozzle means (86) comprises a spray nozzle for injecting water into the heating portion of the tube. 2. The clamp according to claim 1, wherein the clamp is mounted against the axially spaced clamping members (52, 52 ') and the spaced clamp member for movement in a direction perpendicular to the axis of the tube. Annealing device, characterized in that it consists of a pair of movable clamp members (54, 54 ') that exert a force on the tube. 7. The annealing device according to claim 6, wherein the movable clamp member is moved by an air cylinder (60). 2. An annealing device according to claim 1, characterized in that the means (40) for returning the carriage comprise an air cylinder (40). The apparatus of claim 1, further comprising a straightening roller means 94 positioned upstream to move the tube through the annealing chamber, the annealing chamber having the tube at its axially opposite end. And an opening (32 ', 34') for receiving. 10. The annealing chamber according to claim 9, wherein the annealing chamber is covered with a top plate (33) and is located in the middle of the end and has inlet means (80) for receiving an inert gas, said inert gas being the Annealing device, characterized in that it exits from the chamber through axially opposed openings (32 ', 34'). 7. The pair of flexible electrical cables 66 according to claim 6, wherein said clamping member is carried by said pedestal 12 which is adapted to transmit an electric current to said clamping portion for heating at least one separating portion of the tube. And an movable clamp member (54,54 ') electrically insulated from each other. 2. The annealing apparatus of claim 1, wherein the means for heating and annealing comprises a pair of flexible electrical cables attached to the pair of clamp members for resistively heating the separated portions of the tube. . The annealing chamber 132 of claim 1, wherein the means for heating and annealing is between a pair of spaced clamp members 152,152 ', 154, 154' for inductively heating the separation portion of the tube. And an induction heating coil (188) mounted to the shaft, wherein the axis of the coil coincides with the axis of the tube. The annealing device according to claim 13, wherein the induction heating coil is connected to a cooling water supply and discharge tube (190, 190 '). 15. The method of claim 14, wherein the induction heating coil comprises a solid bar (188 ') coupled to the hollow tube (188 "), which bar is connected to the electrical cable means (166) and the hollow tube supplies cooling water. And annealing device characterized in that connected to the discharge tube (190, 190 '). The heating and annealing means according to claim 1, wherein the means for heating and annealing comprises a radiant heating chamber (291) mounted to an annealing chamber (23) for heating the separating portion of the tube. An annealing device, characterized in that it matches. 17. The annealing apparatus as claimed in claim 16, wherein the radiant heating chamber includes a plurality of gas burners (292) radially toward the tube and the inner reflective wall surface (293). 18. The annealing device of claim 17, wherein the inner reflective wall surface is surrounded by a coolant jacket. In a method of selectively annealing a spaced portion of a continuously moving constant length tube 30 being guided to move in one direction of the axis, the mounting pedestal 12 in the direction of the tube axis such that a portion of the tube is in the chamber. Mounting an annealing chamber (32) on the carriage (28) with a tube receiving opening at its end for reciprocating with respect to it; Clamp members 52, 52 ', 54, 54 which space a portion of the tube relative to the annealing chamber at an upstream end of the annealing chamber such that the carriage and the annealing chamber move with the moving tube in a downstream direction. Fixing to '); When the tube is fixed, heating a portion of the tube to an annealing temperature, and releasing the tube; Returning said carriage and annealing chamber to an initial upstream position relative to a mounting pedestal. 20. The method of claim 19, further comprising the step of cooling the heating portion of the tube after the clamping of the tube is released by passing through a liquid denominator quenching chamber 34 placed immediately downstream of the annealing chamber. How to anonymize. 21. The method of claim 20, wherein said cooling step returns said carriage and annealing chamber to their initial upstream position. 21. The method of claim 20, wherein said inert gas is supplied to said annealing and quenching chamber.

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