DK142693B - Method of attaching an elongated metal element to one side of a flat metal plate as well as systems for use in the practice of the method. - Google Patents

Description

(11) PUBLICATION 142693 DENMARK (si) i / oo § (21) Application No. 22l / 67 (22) Filed on 1 3 · Jan. 19 ^ 7 (24) Race day 15 Jan. 19 ^ 7 (44) The application presented and the petition published on 22nd C. 1980 THE DIRECTORATE OF _ ^. u.

PATENT AND TRADE MARKET (30) Priority requested from it

Jan. 28 1966, 523619, US

(71) THE STOLLE CORPORATION, 1501 Michigan Street, Sidney, Ohio, US.

(72) Inventor: Edward George Beck Jr., 532 South Fort Thomas Avenue,

Fort Thomas, Kentucky, U5.

(74) Plenipotentiary in the proceedings:

The engineering firm Lehmann & Ree. (54) Method of attaching an elongated metal element to one side of a flat metal plate as well as systems for use in the practice of the method.

The invention relates to a method of attaching an elongated metal element, e.g. a tube to one side of a flat metal plate, the method of which comprises an elongated metal strip having a lower melting point than both the plate and the element on the metal plate along the place where the element is to be secured, that the element is placed in place, where it is to be fixed in contact with the strip that the strip is heated to a temperature above the melting point of the strip but below the melting points of the plate and the element and that the assembly of the element, plate and strip is cooled.

A method of this kind is known from the disclosure of U.S. Patent No. 2,359,926. In this known method, an element is used in the form of an aluminum tube having a flat side in which a groove is recessed. In the groove, a welding wire or rod is inserted, and after the tube has been bent to the desired shape, the tube with the flat side facing a flat aluminum plate is placed and this assembly is heated to a temperature at which the wire or rod melts. so that the tube and plate are interconnected. Then, the unit can be used to prepare the walls of a cooling unit, e.g. by bending the plate with the attached tube to substantially U-shape. In said disclosure to United States Patent No. 2,359,926, it is stated that an important advantage of the invention described therein is that there are no joints in the single continuous piece of aluminum pipe, nor that there are no joints between the pipe and aluminum plate, and that the construction results in excellent heat transfer, since no joints exist to inhibit the heat flow, and no breakage can occur with respect to joints due to different heat expansions and no corrosion can occur. originating from galvanic effect due to the presence of dissimilar materials and the whole unit can be given a uniform finish by means of anodic cladding.

The method of the present invention is characterized in that the plate is clamped under uniform pressure over substantially all of the portion of its surface covered by the element, maintaining the mutual positioning of the element, plate and strip while continuously exerting pressure on the plate. the element and parallel heating of the assembly of element, plate and strip, and that the assembly of element, plate and strip is cooled at a relatively high temperature below the setting temperature of the strip until the strip is solidified. Hereby it is obtained that the plate, by virtue of its clamping under uniform pressure over substantially all of its surface and by the continuously exerted pressure on the element, is prevented from distorting or throwing during the heating, and also the high temperature during solidification contributes to that the plate is prevented from distorting, so that the plate retains a high degree of flatness, even if the plate and element should consist of metals with different heat expansion coefficients, and even if it is a very thin metal plate. Thereby, it is possible to produce radiant heat radiator cooling panels which are distinguished by the fact that the side of such a panel facing a living room appears as a completely smooth surface, even if that side of the panel is considered under a very point of view.

It has been found that excellent results are obtained by using a plate consisting of aluminum and an element consisting of a copper pipe, if according to the invention a strip consisting of a solder having the composition 91% tin and 9% zinc is used. , although the two materials aluminum and copper have quite different coefficients of expansion. In the application of these materials, a heating temperature of approx. 266 ° C and a cooling temperature of approx. 149 ° C, making sure that there is no excessive temperature decrease during solidification. Also, a relatively long heating time and a relatively long cooling time are important to prevent the plate from folding, and experiments have shown that excellent results are obtained if the heating step according to the invention is maintained for approx. three minutes, said uniform pressure being approx. 0.046 kp./cm 2, and if the cooling temperature is maintained for approx. 2 minutes.

The invention also relates to a plant for use in the method, which plant according to the invention is characterized by at least one processing station, wherein the element and the plate are assembled, heated and cooled, and which comprises a teach for positioning the element relative to the plate and arranged to keep the element and plate assembled correctly during the heating and cooling operation.

An embodiment of the plant according to the invention is characterized in that the leather comprises a flat metal support plate which is stable to form at a working temperature, e.g. of the order of 266 ° C and having at least one length and width substantially the same size as the length and width of the metal plate, a block of non-metallic material having good mechanical strength at said working temperature and with relatively poor thermal conductivity and at least the same length and width as the supporting plate and attached to the underside thereof, which block has a recess formed on its underside to accommodate the elongate member and with a depth greater than the diameter of the elongated member, and a resilient member. means resiliently secured in said recess, which is a resilient member of a material which will retain its resilience at said working temperature and wherein said resilient member exerts a pressure against said elongate member when said elongated member is in said recess and tangles the plane of said recess. the underside of the teacher. This embodiment of the plant is advantageous in ensuring that the heat during the heating step is located to the plate and the element, since the block of non-metallic material prevents the heat from being dissipated to the support plate, which in turn gives the leather the necessary physical strength, and furthermore For example, a uniform pressure exertion on the element is assured, namely by the resilient member, which, when the leather is placed against the plate, will be compressed until the plane of the underside of the leather touches the plate. In a particularly simple embodiment, the resilient member of the invention is a resilient pad. Eg. such a cushion may consist of silicone rubber.

According to a preferred embodiment of the plant, said processing station according to the invention comprises a collecting station, a heating station and a cooling station, each comprising a metal support plate of a material which is stable to temperatures at which they can be exposed, which support plates have planar upper sides. located in a row in a common horizontal plane under a metal belt having both thermal conductivity properties and arranged to pass across the support plates between the stations, where there are means for moving the belt relative to the stations, means for heating the support plate at the heating station to the melting temperature of the solder and by means for heating the support plate at the cooling station to the solidifying temperature of the solder. This embodiment of the plant is advantageous in that the process by it can be carried out in a very rational and economically advantageous way, since the heating station and the cooling station can be kept at constant temperatures, so that one and the same station need not alternately be heated and cooled. Admittedly, the metal belt will be heated as it is above the heating station and thus will include heat to the cooling station, but thereby avoiding too abrupt cooling of the metal belt transported by the metal belt with the leather placed thereon. By virtue of the leather block of non-metallic material, however, the leather will not cause any significant heat transfer from the heating station to the cooling station. In order to simplify the system, the collection and cooling station according to the invention may be one station.

The invention will now be explained in more detail with reference to the drawing, in which fig. 1 shows a schematic side view of an embodiment of the plant according to the present invention; FIG. 2 is a top view of the same, and FIG. 3 is a greatly enlarged cross-sectional view taken along line 3-3 of FIG. 2, showing details of a teaching which can be used in the practice of the method of the invention.

Briefly, in the practice of the invention, a teaching is used to first assemble a tube and plate. The leather is composed of a metal plate with such properties that it will not be distorted at the temperatures that occur during soldering or impact soldering. To the underside of the metal plate is attached a block of the same dimensions as the plate and a material which is non-metallic and has relatively poor thermal conductivity but sufficient mechanical strength to maintain its physical integrity without bias at the temperatures which occurs during the soldering or brazing operation. The ladder should have at least the same dimensions in the horizontal plane as the plate to which the tube is to be joined. The underside of the non-metallic block should have one or more grooves of a width sufficient to accommodate the element to be attached to the plate and at a depth greater than the thickness of the element to be attached to. plate. Attached within the groove or grooves, there is a resilient backing element having a thickness such that it is greater than the difference between the depth of the groove and the thickness of the element to be attached to the plate.

Generally, the plant consists of three flat steel blocks which serve as support plates having their upper surface in a common horizontal plane and arranged in a row with a thin metallic bell with good thermal conductivity arranged and designed to move over the top surface of the blocks. The first block serves as a collecting station where the plate, solder or brazing material and the tube are assembled with the leather for brazing or brazing. The belt is then designed to transport the assembly to a heating station on the second block where the assembly is heated to a temperature above the melting point of the soldering or brazing agent used. The bolt is then designed to move the assembly to a cooling station on the third block where the assembly is still being heated, but to a temperature below the solidification point of the brazing or brazing agent used.

Referring now in more detail to the drawing, the collection station is shown in FIG. 1 at A, the heating station at B and the cooling station at C. At each station a flat block of annealed steel of uniform thickness and with flat top and bottom surfaces is provided. These blocks or support plates are indicated at 10, 11 and 12. Over these three blocks having their upper surface in a common horizontal plane, a belt 13 is arranged to pass. The belt 13 must have good thermal conductivity and may be of perforated aluminum with a thickness of 0.8 mm. In FIG. 1, the ladder and the parts to be assembled there are generally denoted by 14a at the collection station A, and with dotted lines, the teaching is shown at 14b at the heating station B, and at 14c at the cooling station C.

By way of example, in FIG. 2 at station A is shown a pipe piece 15 which has sinusoidal appearance, which is to be joined with the aluminum plate, which is seen at 16 in fig. 1 and 3. It will be appreciated that the particular configuration of the tube 15 is shown by way of example only and that the tube may have any desired number of turns.

Referring to FIG. 3, the surrender ratio of the tube 15 and the plate 16 with the leather 14 will now be described. The leather, generally denoted by 14a, is composed of a metallic support plate such as e.g. may be a cast aluminum working plate 17. Such plate may have a thickness of e.g. 25.4 mm. Attached to the support plate 17 by bolts 18 is a block 19 of a non-metallic material having relatively poor thermal conductivity but sufficient mechanical strength to maintain its physical integrity without biasing at brazing or brazing temperatures. For example, block 19 may be made of asbestos fiber with an inorganic binder. For example, the block 19 3 may have a thickness of 25.4 mm and a density of 1040 kg / m.

The underside of the block 191 is provided with the groove or grooves 20, and in a view of FIG. 2, it is clearly seen that the groove 20 must have a design in such a way that the pre-bent piece of pipe 15 can lie in the groove. As shown in FIG. 3, the width of the groove 20 is such that it conveniently accommodates the tube 15 and its depth is greater than the diameter of the tube 15. Attached to the bottom of the groove 20 are one or more strips 21 of a resilient material which will retain its resilience at solder or brazing temperatures. For example, the strip may be of a silicone rubber composition having a surface hardness of 30 durometers. The thickness of the strip or support 21 is greater than the difference between the diameter of the tube 15 and the depth of the groove 20.

When assembling the pipe and the plate for soldering or brazing, the plate 16 is placed in position and then the soldering or brazing agent is placed on the plate at the location which will be received by the tube. The soldering or brazing means is given in FIG. 3 at 22, and it will be appreciated that a suitable flux will also be used in conjunction with material 22. In the present case, a solder consisting of 91% tin and 9% zinc is used. The soldering or brazing means 22 may be applied in the form of a band or in the form of a wire. When the word "strip" in the claims is used in connection with the soldering or brazing agent, it is intended that this word includes the brazing or brazing agent in the form of a ribbon or thread. If it is in the form of a ribbon, the tube 15 is laid on the ribbon and if it is in the form of a thread, the thread is laid in such a way that the tube 15 communicates with the thread on one or both sides.

The bearing 14a is then placed over the assembly of plate, tube and solder or brazing means, and it is understood that tube 15 is consequently pressed against plate 16 by virtue of the suspension of the strip or substrate 21.

In the particular example shown, the flat sheet element has a thickness of 1 mm and is of aluminum, while the tube is of copper with an internal diameter of 13 mm and with a wall thickness of 0.7 mm. The weight of the leather is sufficient to impart an average unit pressure of approx. 0.01 kp / cm.

When the assembly, as shown in FIG. 3, when the belt 13 is moved in any desired manner to bring the leather and plate and tubes to station B. With the particular solder described above, the block 11 is heated by any desired means to a temperature of approx. 266 ° C. This temperature is above the melting point of the solder used but below the melting point of the aluminum plate and the copper pipe, and, of course, the belt 13. At station B, it is desirable to increase the unit pressure on the plate 16, and additional weight must be placed on top of the leather to bringing the unit pressure up to about 0.045 kp / an ^. With the particular materials described above, assembly 14b is held at station B for approx. 3 minutes. It will be understood that as the soldering or brazing agent melts, the suspension of the strip or substrate 21 continuously presses the tube 15 downwardly so that the tube 15 is in line contact with the plate 16, with the solder forming brakes between the tube and the plate on both sides of the tube. as seen clearly in FIG. 3. If the solder is in thread form, the tube is initially pressed against the plate and as the solder wire melts, it floats and forms brakes on both sides of the tube in the same manner. With the particular solder and flux described above, good humidification is obtained and the assembly is ready for cooling after approx. 3 minutes.

The belt is then moved again in any desired manner to bring the assembly to the position indicated at 14c at station C, which is the cooling station. It has been found that it is critical to control the cooling of the soldering or brazing agent down to the solidification temperature if folding or biasing of the plate 16 is to be prevented. There is a maximum temperature difference between block 11 and block 12 over which biasing or folding of plate 16 will be experienced.

The maximum temperature difference must be determined experimentally for each combination of sheet material and thickness, as well as the material and size of the linear element. Accordingly, station C is actually also a heating station, the block 12 being heated; for the particular composition described, it is heated to a temperature of about 149 ° C. With the particular solder and materials as described above, the solder will solidify at approx. 2 minutes with the block at station C at a temperature of 149 ° C; then the solder will have developed sufficient physical properties to allow assembly 14c to be removed by means of the belt 13 to a take-off station where the leather can be lifted simply by

Claims (7)

8 and the assembly of the plate 16 and the tube 15 can be removed from the apparatus. In summary, it is noted that from the moment the leather is assembled over the sheet 16, the sheet 16 is tightly confined throughout its area, except for the grooves 20, between the bottom surface of the non-metallic block 19 and the top surface of the belt 13, which in turn rests on the blocks 12 surface successively while the tube 15 is kept tightly in contact with the plate 16. In the practice of this invention, it has been found that if the guidelines set forth herein are followed, an excellent joint is obtained both from the mechanical standpoint and from the heat transfer standpoint between the aluminum plate. and the copper pipe, and the aluminum sheet retains its great degree of flatness and is in no way biased. It is possible that, due to the difference in coefficient of heat expansion between the aluminum sheet and the copper pipe, there may be a deviation from flatness as the assembly is cooled to room temperature, but if such deviation from flatness occurs, it will take the form of a uniform rounding with a large radius in one direction, which rounding can later be removed by a simple straightening operation which will leave the plate 16 substantially flat without folds, waves or other signs of localized bias. It will be appreciated that while the invention is particularly well suited to the manufacture of heating cooling jet panels, it can be used with equal success where it is desired to attach stiffening elements of the same or other metal to one side of a plate where it is desired to maintain. the flatness of the plate. Claims. A method of attaching an elongated metal element, e.g. a tube to one side of a flat metal plate, the method of which comprises an elongated metal strip having a lower melting point than both the plate and the element on the metal plate along the place where the element is to be secured, that the element is placed in place, where it is to be fixed in contact with the strip, that the strip is heated to a temperature above the melting point of the strip but below the melting points of the plate and element and that the assembly of element, plate and strip is cooled, characterized in that the plate is clamped under uniform pressure to it substantially the entire portion of its surface covered by the element / that the mutual positioning of the element, plate and strip is maintained while the pressure is continually exerted on the element and parallel heating of the assembly of element, plate and strip, and that the assembly of element, plate and strip is cooled at a relatively high temperature below the setting temperature of the strip until strip n is solidified. Process according to claim 1, wherein an aluminum plate and a copper tube element are used, characterized in that a strip comprising a solder having the composition 91% tin and 9% zinc is used. Process according to Claim 1, characterized in that a heating temperature of about 266 ° C and a cooling temperature of approx. 149 ° C. Process according to claims 1 and 3, characterized in that the heating step is maintained for approx. 3 minutes, the said 2 uniform pressure being approx. 0.046 kp / cm and the cooling temperature is maintained for approx. 2 minutes. System for use in the method according to claim 1, characterized by at least one processing station (A, B, C), wherein the element (15) and the plate (16) are assembled, heated and cooled, comprising a ladder (14a) for positioning the element relative to the plate and arranged to hold the element and plate correctly assembled during the heating and cooling operation. Installation according to claim 5, characterized in that the ladder (14a) comprises a flat support plate (17) of metal which is stable to form at a working temperature, e.g. of the order of 266 ° C and having at least one length and width substantially the same size as the length and width of the metal plate (16), a block of non-metallic material (19) having good mechanical strength at said working temperature and with relatively poor thermal conductivity and at least the same length and width as the support plate (17) and attached to the underside thereof, which block has on its underside a recess (20) designed to accommodate the elongated member, and a resilient member ( 21) which is fixed in the recess which is a resilient member of a material which will retain its resilience at said working temperature and wherein the resilient member exerts pressure against the elongate member when the elongated member is in the recess and tangles the plane for the underside of the teacher. Installation according to claim 6, characterized in that the resilient member (21) is a resilient pad.