Heat exchanger module for arrangement on a welding system and having a nonwoven filter, and welding system

Abstract

A heat exchanger module (22) for removable arrangement on a soldering system (10), in particular on a reflow soldering system, the heat exchanger module (22) comprising a non-woven filter (70); and a welding system.

Description

[0001] The invention relates to a heat exchanger module for arrangement on a soldering system, in particular on a reflow soldering system. The heat exchanger module has an inlet for admitting process gas from the soldering system, a transfer chamber in which a heat exchanger element through which a coolant can flow is arranged, and an outlet for discharging process gas from the heat exchanger module into the soldering system. The heat exchanger element has an upper surface through which the process gas can flow. During operation, the arrangement is such that the process gas passes from the inlet through the transfer chamber and is guided to the outlet through the heat exchanger element arranged in the transfer chamber for cooling the process gas.

[0002] Such heat exchanger modules are installed by the applicant, for example, in the Hotflow 4 reflow soldering system available at the time of filing. The heat exchanger modules serve to cool heated process gases in the respective process zones, in particular in the cooling zone. The process gases contain both particles and vaporized soldering flux as well as soldering fumes, which condense during the cooling of the process gases. It has been shown that condensate and deposits form on the surfaces of the heat exchangers. This causes the heat exchanger elements to become clogged after a relatively short period of time, which necessitates cleaning or replacement of the heat exchanger elements.

[0003] The object of the invention is to prevent a heat exchanger element from becoming blocked, in particular by particles and condensate, for as long a period of time as possible.

[0004] This object is achieved by a heat exchanger module having the features of claim 1 and by a welding system having the features of claim 10 .

[0005] Therefore, in particular, it is proposed that the heat exchanger module has a first receiving element for the reel of a nonwoven filter, and a second receiving element for receiving the nonwoven filter unfolded from the reel. Two receiving elements are arranged so that, when the nonwoven filter is present on the receiving element, the nonwoven filter is guided to the second receiving element from the first receiving element above the top of the heat exchanger element. This ensures that the process gas is passed through the nonwoven filter immediately before entering the heat exchanger element. Therefore, the particles contained in the process gas and any condensate formed can be adsorbed by the nonwoven filter. By arranging the receiving element and the reel of the nonwoven filter, before the nonwoven filter is blocked by particles and condensate, the reel of the nonwoven filter can be unfolded so that the fresh, unblocked area of ​​the nonwoven filter is guided above the top of the heat exchanger element. In particular, the reel of the nonwoven filter can be unfolded when the welding system is in operation; therefore, the welding process is not interrupted, or is not adversely affected in any other way.

[0006] In addition, it is advantageous if a driver for rotatingly driving at least one receiving element is provided. Preferably, the receiving element on which the nonwoven filter is wound is a driven receiving element. In this case, the nonwoven filter can be moved on the top of the heat exchanger element by the driver. In this case, the drive can be carried out continuously, or when the nonwoven filter is expected to be blocked, or when the nonwoven filter is blocked.

[0007] In order to determine the state of the nonwoven filter, it is advantageous if a sensor unit is provided for providing a sensor signal, which represents the degree of contamination and / or the flow resistance of the nonwoven filter area guided on the upper side of the heat exchanger element. The sensor unit can be an optical sensor unit in particular, which detects the degree of contamination, for example, by image comparison and image recognition. It is also conceivable that the sensor unit determines the flow resistance of the nonwoven filter and determines the degree of contamination of the nonwoven filter according to the changing flow resistance when the nonwoven filter is blocked. By providing the sensor signal, it is possible to detect whether the nonwoven filter present on the top of the heat exchanger element is so dirty and blocked that it is necessary to move the nonwoven filter, and in particular whether it is necessary to control the drive to replace the nonwoven filter area present on the top of the heat exchanger element.

[0008] Furthermore, it is advantageous if a control unit for controlling the drive is provided, the control unit being configured such that the control unit controls the drive as a function of the sensor signal. This allows automatic control of the drive for replacing the nonwoven filter area on top of the heat exchanger element. Furthermore, it is also conceivable that the control unit is designed to control the drive in a continuous mode or in a periodic rhythm determined by an operator.

[0009] In addition, it has been proved that it is advantageous if a main housing is provided, in which the heat exchanger element is arranged, and a receiving housing for receiving a corresponding receiving element is provided on two opposite sides of the main housing respectively. The reel of fresh nonwoven filter can be inserted into a receiving element in the receiving housing. Then, the free end of the nonwoven filter can be guided to another receiving element in its own receiving housing by the main housing, and is attached to the receiving element at this. By appropriately driving the receiving element that receives the free end of the nonwoven filter, the nonwoven filter can be launched from the reel. Since each receiving element has its own housing, the existing heat exchanger module without nonwoven filter can be refurbished.

[0010] In this case, it is advantageous if the driver is flange-connected to one of the receiving housings. The driver can be located outside the receiving housing, inside which a drive shaft is then arranged, which preferably extends through the receiving housing to the receiving element.

[0011] Furthermore, it has proven to be advantageous if at least one of the receiving housings has an inclined side which is parallel to its longitudinal axis and inclined relative to the upper side of the heat exchanger element. This arrangement is relatively space-saving and also operationally reliable.

[0012] Preferably, the inclined side has a window so that the condition of the nonwoven filter in the corresponding receiving housing can be checked by visual inspection. In addition, the inclined side is preferably designed to be openable so that the roll or the nonwoven filter can be replaced without having to open the main housing in which the heat exchanger element is arranged.

[0013] The heat exchanger element is preferably arranged so that it can be pulled out of the main housing in a drawer-like manner and replaced in this way. This allows the contaminated heat exchanger element to be easily removed from the main housing, while the nonwoven filter present above the heat exchanger element does not hinder the replacement of the heat exchanger element. The arrangement is preferably such that the removed heat exchanger element can be inserted into the main housing without colliding with the nonwoven filter. The arrangement is also preferably such that the heat exchanger element can be pulled out of the main housing in a drawer-like manner parallel to the plane where the top of the heat exchanger element is located or the heat exchanger element can be pushed into the main housing.

[0014] The objects mentioned at the outset can also be achieved by a soldering system, in particular a reflow soldering system, which has a process channel in which a process gas is conducted and on which a heat exchanger module according to the invention is arranged, in particular removably.

[0015] Further details and advantageous embodiments of the invention can be found in the following description, based on which an embodiment of the invention is described and explained in more detail.

[0016] In the attached picture: Figure 1 It is a welding system with a heat exchanger module; Figure 2 Is a separate basis Figure 1 heat exchanger module; Figure 3 is through according to Figure 2a cross section of a heat exchanger module; and Figure 4 is through according to Figure 1 Longitudinal section of a heat exchanger module.

[0017] Figure 1 The soldering system 10 is a reflow soldering system 10 without a cover, so that the individual modules and elements of the soldering system 10 can be seen. The soldering system 10 has an inlet 12, through which a circuit board to be soldered and equipped with electronic components can be introduced into the soldering system 10. The soldering system 10 has an outlet 14 on the side opposite to the inlet 12, from which the soldered circuit board can be removed. The circuit boards are transported from the inlet 12 in a process direction 13 to the outlet 14 via a transport system (not shown). The soldering system 10 has various soldering zones, in particular a preheating zone 16, a process zone 18 and a cooling zone 20. In the different zones 16 to 18, different temperatures exist. In order to reduce the temperature in the cooling zone 20, a preheating zone 16 is provided. In the cooling zone 20, a preheating zone 18 is provided. In the cooling zone 20, a preheating zone 16 ... Figure 1 2 shows a heat exchanger module 22 by way of example. According to the invention, in the cooling zone 20 or other zones, a plurality of heat exchanger modules 22 can be provided. The heat exchanger module 22 is removably arranged on a longitudinal beam 24 extending in the longitudinal direction of the welding system 10. With the heat exchanger module 22, the process gas can be removed from the process channel, cooled and fed back into the process channel.

[0018] from Figure 2 (It shows the heat exchanger module 22 separately on the longitudinal member 24) It is clear that the heat exchanger module 22 comprises a main housing 26 and two receiving housings 28, 30. The two receiving housings 28, 30 are fastened to the main housing 26 on opposite sides of the main housing, respectively. The receiving housing 28 faces the machine inlet 12 and the receiving housing 30 faces the machine outlet 14.

[0019] The main housing 26 is substantially cuboid and has a lever 34 on its longitudinal front side 32, with which the main housing 26 can be opened and with which a heat exchanger element 36 present in the main housing 26 (which can be removed) can be removed. Figure 3 and Figure 4 ) is pulled out of the main housing 26 in a drawer-like manner transversely to the process direction 13 and essentially horizontally along the arrow 38.

[0020] As from Figure 2 It is further clear that the two receiving housings 28, 30 each have an inclined side 40 extending parallel to their longitudinal axis (which extends transversely to the process direction 13) and inclined relative to the upper side of the heat exchanger module 22. On the respective inclined side 40, an openable window 42 is provided, which can be locked with a rod 44 respectively.

[0021] The cover element 46 (not shown) can also be opened by removing or pivoting it. Figure 2 but shown in cross section at Figure 3 and Figure 4 In this case, the cover element 46 rests on a Figure 2 The peripheral seal 48 is clearly seen in FIG.

[0022] As according to Figure 3 and Figure 4 As is clear from the cross section of FIG. 2 , the heat exchanger module 22 has an inlet 50 for introducing a process gas 52 from the welding system 10. The inlet 50 leads to a transfer chamber 54 in which the heat exchanger element 38 is accommodated. The heat exchanger element 38 itself is designed so that a coolant, in particular water, can flow through it, for which purpose a cooling device such as the one shown in FIG. 2 is provided. Figure 2 The connectors 56, 58 shown in FIG. Figure 3 In the cross section of FIG. , only the connecting member 58 is visible. Figure 3 The distribution pipe 60 shown in FIG. 1 is provided for distributing the coolant in the heat exchanger element 36. Thus, during operation of the welding system, the process gas 52 is passed into the transfer chamber 54 through the inlet 50. Furthermore, the process gas 52 is passed through the substantially horizontally arranged heat exchanger element 38, the process gas 52 entering the heat exchanger element 36 at the top 62 and leaving the heat exchanger element 36 at the bottom 64 thereof. The cooled process gas 66 then leaves the heat exchanger module 22 via an outlet 68 provided on the heat exchanger module 22 and is fed back into the process channel.

[0023] In order to prevent the heat exchanger element 36 from being contaminated by particles or condensate, a nonwoven filter 70 is provided on the top 62 of the heat exchanger element 36 (which is particularly suitable for the case of a heat exchanger element 36). Figure 4 clearly visible in the cross section).

[0024] A first receiving element 72 is provided in the receiving housing 30, on which a roll 74 with nonwoven material 70 is arranged. The nonwoven material 70 from the roll 74 extends over the top 62 of the heat exchanger element 36 to a second receiving element 76 present in the receiving housing 28, on which the used nonwoven material 70 leaving the transfer chamber 54 is wound on a roll 75. In this case, the arrangement is such that the nonwoven material 70 present in the receiving chamber 54 at least for the most part completely covers the top 62 of the heat exchanger element 36 and extends to the openings 79 present on the main housing 26 and the receiving housings 28, 30.

[0025] In order to unwind the nonwoven material 70 from the receiving element 72 and to wind the nonwoven material 70 onto the receiving element 76, a drive 78 is provided, which can be driven by Figure 2The drive 78 is in this case flange-connected to the receiving housing 28 , the drive shaft of the drive 78 passing through the housing wall of the receiving housing 28 and being rotationally coupled to the receiving element 76 .

[0026] Furthermore, a sensor unit 82 is provided, which is schematically shown in FIG. Figure 2 The sensor unit 82 is used to generate a sensor signal 84, which is representative of the degree of contamination or flow resistance of the nonwoven filter 70 guided on the top 62 of the heat exchanger element 36. The sensor signal 84 is fed to the control unit 80, such as Figure 2 As indicated in . Depending on the sensor signal 84, the control unit 80 can then drive the drive 78. Thus, if a high degree of contamination is detected via the sensor unit 82, the drive 78 is activated, whereby the contaminated nonwoven filter 70 is wound onto the receiving element 76 and a fresh, unused nonwoven filter 70 is unwound from the receiving element 72 until eventually the entire top 62 of the heat exchanger element 36 is covered by a fresh nonwoven filter 70.

[0027] In general, this can ensure that a sufficiently clean nonwoven filter 70 is always placed on the top 62 of the heat exchanger element 36. This arrangement can make it possible to continuously or discontinuously provide the nonwoven filter with fresh filter material 70 on the top 62 of the heat exchanger element 36 during operation of the welding system 10, depending on the degree of contamination. As a result, the heat exchanger module 22 can be operated for a relatively long time without malfunctioning due to deposits or contamination.

Claims

1. A heat exchanger module (22) for being removably arranged on a soldering system, in particular on a reflow soldering system, the heat exchanger module comprising: an inlet (12) for admitting a process gas (52) from the welding system (10); a transfer chamber (54), in which a heat exchanger element (36) is arranged through which a coolant can flow, the heat exchanger element (36) comprising a top (62) onto which the process gas (52) can flow; and an outlet (68) for discharging process gas (66) from the heat exchanger module (22) into the welding system (10), arranged such that during operation the process gas (52, 66) passes from the inlet (50) through the transfer chamber (54) and is directed to the outlet (68) through the heat exchanger element (36) disposed in the transfer chamber (54), It is characterized in that The heat exchanger module (22) has: a first receiving element (72) for a roll (74) including a nonwoven filter (70); and a second receiving element (76) for receiving the nonwoven filter (70) unrolled from the roll (74), the two receiving elements (72, 76) being arranged so that when the nonwoven filter (70) is present on the receiving elements (72, 76), the nonwoven filter (70) is guided from the first receiving element (72) to the second receiving element (76) above the top (62) of the heat exchanger element (36).

2. The heat exchanger module (22) according to claim 1, characterized in that A drive (78) is provided for rotationally driving the first receiving element and / or the second receiving element (76).

3. The heat exchanger module (22) according to claim 1 or claim 2, characterized in that: A sensor unit (82) is provided for providing a sensor signal (84) which is indicative of the degree of contamination and / or the flow resistance of a nonwoven filter region guided over the top (62) of the heat exchanger element (36).

4. The heat exchanger module (22) according to claim 3, characterized in that A control unit (80) is provided for controlling the driver (78), and the control unit (80) is configured such that the control unit (80) controls the driver (78) according to the sensor signal (84).

5. The heat exchanger module (22) according to any one of the preceding claims, characterized in that A main housing (26) is provided, in which the heat exchanger element (36) is arranged, and receiving housings (28, 30) for receiving corresponding receiving elements (72, 76) are provided on two opposite sides of the main housing (620).

6. The heat exchanger module (22) according to claims 3 and 5, characterized in that The driver flange is connected to one of the receiving housings.

7. The heat exchanger module (22) according to claim 5 or 6, characterized in that At least one of the receiving housings (28, 30) has an inclined side (40) extending parallel to its longitudinal axis and inclined relative to the top (62) of the heat exchanger element (36).

8. The heat exchanger module (22) according to claim 7, characterized in that The inclined side (40) has a window and / or is designed to be openable.

9. A heat exchanger module (22) according to any one of the preceding claims, characterized in that The heat exchanger element (36) is arranged so that the heat exchanger element (36) can be pulled out of the main housing (26) in a drawer-like manner and replaced.

10. A soldering system (10), in particular a reflow soldering system, comprising: a process channel for conveying process gas (52); as well as A heat exchanger module (22) according to any one of the preceding claims, arranged on the process channel.

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