Coupling device for thermal length compensation

Abstract

The invention relates to a coupling device (1) for fluidically coupling a stationary first device (2) and a stationary second device (3) by means of a flow channel (4) and for telescopically compensating for thermal expansions along an axial extension (5) of the flow channel (4) while maintaining the fluidic coupling, wherein a standpipe device (6) is provided with a standpipe section (8) and with a first partial channel (9) that can be fluidically coupled to the first device (2), and an immersion pipe device (7) is provided with a second partial channel (11) that can be fluidically coupled to the second device (3), wherein an immersion pipe section (10) of the immersion pipe device (7) is partially telescopically received in the standpipe section (8) in the first partial channel (9), and wherein the standpipe device (6) comprises a radially circumferential temperature-control element (15) in a distal first end region (14) of the standpipe section (8).

Description

[0001] COUPLING DEVICE FOR THERMAL LENGTH COMPENSATION

[0002] The invention relates to a coupling device for the fluidic coupling of two devices by means of a flow channel, wherein the coupling device can be used to transfer melt, in particular plastic melt, through the flow channel from a first stationary device to a second stationary device. Since the usual temperature of the plastic material or the like is important during processing into a plastic melt and to maintain the flowability of the plastic melt,the plastic melt and thus the surrounding machine components of the devices and the coupling device is above room temperature, i.e. more than 20°, and in addition when starting up a process for plastics processing and during plastics processing temperature changes of the machine components as well as the plastic melt can occur, the coupling device is further designed in such a way that by means of this, at least in the axial direction of the flow channel, thermal expansions of the fixed devices can be compensated.

[0003] WO 2022 056 618 A1 discloses a melt coupling for an injection molding machine. The melt coupling comprises a dip tube and a heatable standpipe, wherein a flow channel is formed in the dip tube and the standpipe, and wherein the dip tube is telescopically received in a first sub-channel of the standpipe, so that thermal expansions in the axial direction of the flow channel can be telescopically compensated by arranging the dip tube for axial displacement within the first sub-channel. This disclosure further demonstrates the possibility of heating the standpipe and compensating for angular offsets in the axial direction of the melt coupling relative to the machine components of the injection molding machine coupled thereto.

[0004] A disadvantage of the embodiments of a coupling device of this type known from the prior art is that, particularly under repeatedly changing operating conditions, in particular the temperature or pressure of the melt flowing through the flow channel or the temperature of the devices coupled to the coupling device, jamming of the parts of the coupling device that are displaceable relative to one another or leaks in the coupling device can occur.

[0005] The object of the present invention was to overcome the disadvantages of the prior art and to provide a coupling device by means of which the fluidic coupling of two devices, between which a melt can be transferred by means of the coupling device, is designed reliably and safely, in particular under variable operating conditions.

[0006] This object is achieved by a device according to the claims.

[0007] The coupling device according to the invention for the fluidic coupling of a stationary first device and a stationary second device by means of a flow channel of the coupling device for melt and for the telescopic compensation of thermal expansions of the first device, the second device and the coupling device itself along an axial direction of the flow channel while maintaining the fluidic coupling, comprises

[0008] - a standpipe device with a standpipe section and with a first sub-channel that can be fluidically coupled to the first device and

[0009] - a dip tube device with a second sub-channel which can be fluidically coupled to the second device, wherein a dip tube section of the dip tube device is telescopically received in sections in the standpipe section in the first sub-channel, wherein the flow channel is formed by the first sub-channel and the second sub-channel.

[0010] The coupling device is further characterized in that the standpipe device comprises a clamping device in a distal first end region of the standpipe section. The clamping device can be designed to completely encompass the first end region of the standpipe section, wherein it can further be provided that the clamping device extends to a distal outermost first end of the standpipe section. The clamping device can be formed, for example, by a hydraulic clamping ring or a device that functions by a wedge effect, similar to a ring clamping element.

[0011] Furthermore, it can be provided that the clamping device is a radially encircling temperature control element, wherein the radially encircling temperature control element extends to a distal outermost first end of the standpipe section. In this context, a temperature control element is understood to be a controllable element for active cooling or heating. For example, a controllable heating and cooling ceiling is understood to be a temperature control element. This ensures that the first end region of the standpipe section can be easily adjusted in terms of its tolerance to the immersion tube section of the immersion tube device encompassed or delimited by it.In this way, the tightness of the coupling device can also be adjusted particularly reliably, since the coupling device should not be tight at all times depending on the operating state of the devices coupled to it, but the sliding of the immersion pipe section and the standpipe section into each other must also be guaranteed.

[0012] For example, if the first device and the second device are brought from room temperature to an operating temperature of more than 20°C, the fit between the interlocking dip tube and standpipe sections can be adjusted by appropriately tempering the first end region using the tempering element in such a way that smooth compensation of thermal expansion is possible. Once the two devices and also the coupling device have been brought to operating temperature, also by transferring melt through the coupling device, the temperature of the distal end region of the standpipe section can now be adjusted using the tempering element in such a way that a press fit is established between the dip tube section and the standpipe section. This now establishes the tightness of the coupling device.This compensation of the thermal expansion and the subsequent guarantee of the tightness of the coupling device can be carried out very effectively and repeatedly by means of the tempering element in the distal end area of ​​the standpipe device.

[0013] In particular, it can also be provided that the standpipe device has a sharp edge at its distal end in the contact area or near the outer surface of the dip tube device in the dip tube section. This allows any plastic material that has already escaped to be scraped off the outer surface of the dip tube section during further compensation for thermal expansion. This scraping can be adjusted in a particularly simplified manner using the temperature control element, since this element reliably adjusts the fit between the outer surface of the dip tube device in the dip tube section and the inner surface of the standpipe device in the standpipe section.

[0014] Furthermore, it may be expedient for the radially encircling temperature control element to comprise a heating and cooling device or a heating device and cooling fins. This makes it easy to control the temperature of the distal end region of the standpipe device through targeted cooling, but also through targeted heating. The heating and cooling device can, for example, comprise an electric heater and a water cooling system. The precise design of the heating and cooling device is irrelevant, however, as long as a sufficient amount of heat can be supplied to the distal end region and as long as a sufficient amount of heat can also be removed to influence the fit between the standpipe section and the immersion tube section within a specified time interval.

[0015] In this context, a corresponding control or regulating device can also be provided. The control or regulating device can further comprise sensors for measuring the temperature at different positions of the coupling device, in the flow channel and / or on the devices fluidly connected by means of the coupling device. The control or regulating device can further comprise sensors for determining the thermal expansion of the immersion tube section of the immersion tube device and / or the standpipe section of the standpipe device. In cooperation with the temperature control element, a characteristic map for operating conditions can be stored in the control or regulating device so that appropriate measures of the temperature control element can be initiated in response to changes in the operating conditions by means of the control or regulating device.

[0016] Furthermore, it can be provided that the dip tube section of the dip tube device is formed from a second material, wherein the second material has a higher thermal expansion coefficient than a first material of the standpipe section of the standpipe device.

[0017] Alternatively, however, it can also be provided that the first material has a higher thermal expansion coefficient than the second material. In particular, it can also be provided that one of the two materials has the lowest possible expansion coefficient. For example, it can be provided that the dip tube section of the dip tube device is made of Invar or another iron-nickel alloy with similar material properties. This ensures that the diameter of the dip tube section on its outer surface changes as little as possible, depending on the temperature of the melt transferred through the flow channel, compared to the state without melt flow or different melt temperatures.Thus, the fit between the standpipe section and the dip pipe section can be significantly influenced by tempering the standpipe section using the tempering element in order to be able to control the tightness and thermal compensation of the coupling device in the simplest possible way.

[0018] Furthermore, it can be provided that a circumferential groove is formed between the first end region of the standpipe section and a remaining region of the standpipe section facing the coupling to the first device. This measure easily achieves the most effective thermal decoupling possible between the distal first end region and the remaining region of the standpipe section, so that the heat flow between the two regions is minimized. Thus, the distal first end region can be temperature-controlled or thermally influenced largely without further influencing the remaining standpipe device.

[0019] Another advantageous embodiment is one in which the standpipe device in the standpipe section outside the first end region can be heated by means of a circumferential heating element. This simple measure can further influence the fit between the standpipe section and the immersion tube section. In particular, it can positively influence the smoothness of the thermal expansion compensation. In appropriate combination with the previously described measures, this enables the coupling device to respond as quickly as possible to changing operating parameters.

[0020] According to a further development, it is possible for the standpipe device in the standpipe section to comprise a bushing made of a ceramic material or with a ceramic coating that surrounds the first partial channel. This effectively reduces heat transfer between the melt and the standpipe device. Thus, the thermal influence of the melt on the standpipe device is minimized, which subsequently enables improved and simplified adjustment of the fit using the temperature control element, even if the melt temperature may change during operation.

[0021] Furthermore, it may be expedient for the immersion tube device to have circumferential grooves or depressions spaced axially from an outer surface of the immersion tube device in the immersion tube section. This is a further measure to reduce the heat transfer from the immersion tube section of the immersion tube device, which is influenced by the temperature of the melt, to the standpipe section of the standpipe device.

[0022] Furthermore, it can be provided that, when the dip tube device is joined to the standpipe device, the second sub-channel of the dip tube device continuously widens in a distal second end region of the dip tube section towards the inner surface of the first sub-channel, wherein a distal end of the dip tube device, starting from the outer surface of the dip tube device, is undercut by a radially circumferential recess, so that the distal end of the dip tube device is designed as an elastic sealing lip that rests against the inner surface of the first sub-channel and radially circumferentially. Furthermore, in this context, it can be provided that the outermost distal end of the dip tube device, as the end by means of which the elastic sealing lip is formed, has a slightly larger diameter than the outer surface of the dip tube device in the dip tube section.This causes the elastic sealing lip to be pressed against the inner surface of the standpipe device in the standpipe section or in the first sub-channel. When the melt flows through the flow channel from the first device to the second device, through the first sub-channel, and subsequently through the second sub-channel, this simple design measure can improve the tightness of the coupling device.

[0023] Furthermore, it can be provided that the dip tube device in the dip tube section has a transition fit or a clearance fit relative to the standpipe device in the standpipe section at room temperature, in particular at 20°C. This ensures the smooth movement of the coupling device in the idle state or without melt being transferred, thus also enabling its assembly in a simple manner.

[0024] According to a particular embodiment, it is possible for the coupling device to comprise a control or regulating device with at least one sensor for directly or indirectly determining a fit between the outer surface and the inner surface and / or for directly or indirectly determining the stress state of the distal first end region and / or for determining a difference between the diameter of the dip tube device on the outer surface and the diameter of the standpipe device on the inner surface, wherein furthermore at least the tempering element can be controlled and regulated by means of the control or regulating device.

[0025] It can be provided that the sensor is an optical distance sensor, a voltage sensor or a pressure sensor. For example, it is conceivable that the voltage state of the distal first end region of the immersion tube device can be determined by means of the control or regulating device in cooperation with the sensor, so that control of the temperature control element can be initiated in order to change the voltage state. Since the voltage state allows conclusions to be drawn about the fit between the immersion tube device and the standpipe device, the fit can be changed in a simple manner by regulating the temperature control element. The same is possible if the sensor is designed as a pressure sensor or optical distance sensor. In any case, it is conceivable that the coupling device can be controlled by means of the control or regulating device.The control device can be controlled in such a way that, for example, a changed operating state of the two stationary devices or a changed temperature of the melt can be responded to in such a way that, in the event of an increased stress state due to a temperature-related interference fit between the immersion tube device and the standpipe device, a clearance fit is set by appropriately controlling the tempering element in order to thereby enable telescopic compensation of thermal expansion. Once compensation of thermal expansion has then taken place, the tempering element can be controlled in such a way that a interference fit is again established between the immersion tube device and the standpipe device in order to ensure the tightness of the flow channel or the coupling device.

[0026] In the context of the preceding description, the term "distal" is to be understood as a position designation that refers to the outermost end or an outermost region. The opposite would be "proximal," in which case this position designation refers to the middle or a central region of a component, device, or facility.

[0027] For a better understanding of the invention, it is explained in more detail using the following figures.

[0028] They show in a highly simplified, schematic representation: Fig. 1 a cross section of a possible embodiment of the coupling device.

[0029] By way of introduction, it should be noted that in the variously described embodiments, identical parts are provided with identical reference symbols or component designations. The disclosures contained throughout the description can be applied analogously to identical parts with identical reference symbols or component designations. Furthermore, the positional information chosen in the description, such as top, bottom, side, etc., refers to the directly described and illustrated figure, and these positional information must be applied analogously to the new position in the event of a change in position.

[0030] As shown in Fig. 1, the coupling device 1 can be used for the fluidic coupling of a stationary first device 2 and a stationary second device 3, wherein the devices 2 and 3 can be, for example, machines or machine components for plastics processing, wherein a melt or in particular a plastics melt can be transported or transferred between the devices 2 and 3 by means of a flow channel 4 with an axial extension 5 of the coupling device 1. Due to the process, the devices 2 and 3 can undergo heating and cooling cycles when starting up or during operation, which causes thermal expansion of the components of the devices 2 and 3. Since the devices 2 and 3 are stationary, this thermal expansion must be compensated for by the coupling device 1. This length compensation orThis compensation of thermal expansion is made possible by means of a telescopic or telescopic-like compensating movement of the coupling device 1.

[0031] To enable this telescopic compensation of thermal expansion while maintaining the fluidic coupling between the devices 2 and 3, the coupling device 1 can comprise a standpipe device 6 and a dippipe device 7, wherein the standpipe device 6 can have a standpipe section 8 and a first sub-channel 9 that can be fluidically coupled to the first device 2. Furthermore, the dippipe device 7 can have a dippipe section 10 and a second sub-channel 11 that can be fluidically coupled to the second device 3. The dippipe section 10 of the dippipe device 7 can be accommodated in sections in the first sub-channel 9 and thus in the standpipe section 8 of the standpipe device 6.It can be provided that the dip tube device 7 has a first diameter on an outer surface 12 at room temperature or in particular at 20°C with a transition fit or a clearance fit relative to a second diameter on an inner surface 13 of the first partial channel 9 of the standpipe device 6. In any case, the dip tube section 10 thus projects into the first partial channel 9 of the standpipe device 6 in the standpipe section 8, so that the flow channel 4 extending between the devices 2 and 3 along the axial extent 5 is formed by the first partial channel 9 and the second partial channel 11 in order to be able to transport or transfer melt between the devices 2 and 3.

[0032] In order to ensure the tightness of the coupling device 1 in the region of the contacting outer surface 12 and inner surface 13 and, at the same time, the intended sliding of the two sections 8 and 10 into one another for telescopic compensation, a radially circumferential tempering element 15 can also be arranged or formed in a distal first end region 14 of the standpipe section 8. This tempering element 15 can, for example, comprise a heating and cooling device 16 or a heating device 17 and cooling fins 18, so that the first end region 14 of the standpipe section 8 can be tempered according to the operating conditions of the devices 2 and 3 and according to the temperature of the melt flowing through the flow channel 4.This makes it easy to ensure tightness in the first end region 14, and at the same time, the fit between the immersion tube section 10 of the immersion tube device 7 and the standpipe section 8 of the standpipe device 6 can be adjusted in this region, so that in addition to tightness, the smooth sliding of these two sections or the immersion tube section 10 of the immersion tube device 7 into the first sub-channel 9 is ensured. Preferably, the radially encircling tempering element 15 can extend to a distal end 19 of the standpipe section 8.

[0033] In order to further improve these advantageous effects, it can be provided that the dip tube section 10 of the dip tube device 7 is formed from a second material, wherein the second material has a higher thermal expansion coefficient than a first material of the standpipe section 8 of the standpipe device 6.

[0034] The standpipe device 6 can be arranged in the standpipe section 8 outside the first end region

[0035] 14 can be heated by means of a circumferential heating element 21 in order to be able to easily influence the thermal expansion of the standpipe section 8. In addition to this measure, it can also be provided that a circumferential groove 20 is formed between the first end region 14 of the standpipe section 8 and a remaining region of the standpipe section 8 facing the first device 2, whereby the first end region 14 can be thermally insulated as best as possible from the remaining region of the standpipe section 8.

[0036] In order to further improve the thermal insulation of individual components of the coupling device 1, it can further be provided that the standpipe device 6 in the standpipe section 8 comprises a bushing 22 made of a ceramic material or with a ceramic coating, which bushing encloses the first partial channel 9. As a further measure with regard to thermal insulation, it can also be provided that the immersion tube device 7 in the immersion tube section 10 has circumferential grooves 23 or depressions spaced apart in the axial extent 5, starting from an outer surface 12 of the immersion tube device 7 in the immersion tube section 10. This can further reduce the heat transfer from the immersion tube section 10 to the standpipe section 8. These measures, in turn, can improve the tightness of the coupling device 1 and the smooth sliding of the immersion tube section 10 and the standpipe section 8 into one another.

[0037] In order to further improve the tightness of the coupling device 1, it can also be provided that the second sub-channel 11 of the dip tube device 7 in a distal second end region 24 of the dip tube section 10 continuously widens to an inner surface 13 of the first sub-channel 9, wherein a distal end 25 of the dip tube device 7, starting from the outer surface 12 of the dip tube device 7, is formed by a radially circumferential recess

[0038] 26 is undercut, so that the distal end 25 of the dip tube device 7 acts as a radially encircling elastic sealing lip which rests against the inner surface 13 of the first sub-channel 9

[0039] 27 is trained.

[0040] The exemplary embodiments show possible embodiments. It should be noted at this point that the invention is not limited to the specifically illustrated embodiments. Rather, various combinations of the individual embodiments are also possible. This variation possibility, based on the teaching of technical action based on the invention in question, lies within the skill of the person skilled in the art. The scope of protection is determined by the claims. However, the description and drawings must be used to interpret the claims. Individual features or combinations of features from the various exemplary embodiments shown and described may represent independent inventive solutions in themselves. The problem underlying the independent inventive solutions can be derived from the description.

[0041] All information on value ranges in this description is to be understood as including any and all sub-ranges thereof, e.g. the information 1 to 10 is to be understood as including all sub-ranges starting from the lower limit of 1 and the upper limit of 10, ie all sub-ranges begin with a lower limit of 1 or greater and end with an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

[0042] For the sake of clarity, it should finally be pointed out that, in order to better understand the structure, some elements have been shown out of scale and / or enlarged and / or reduced in size.

[0043] Reference symbol list

[0044] Coupling device

[0045] First device

[0046] Second device

[0047] flow channel

[0048] Axial extension

[0049] Standpipe device

[0050] T pipe device

[0051] Standpipe section

[0052] First sub-channel

[0053] Dip tube section

[0054] Second sub-channel

[0055] exterior surface

[0056] inner surface

[0057] First end area

[0058] Tempering element

[0059] Heating and cooling device

[0060] Heating device

[0061] Cooling fins

[0062] Distal end of the standpipe device

[0063] Nut

[0064] heating element

[0065] socket

[0066] grooves

[0067] Second end area

[0068] Distal end of the dip tube device

[0069] recess

[0070] sealing lip

Claims

Patent claims 1. Coupling device (1) for the fluidic coupling of a stationary first device (2) and a stationary second device (3) by means of a flow channel (4) of the coupling device (1) for melt and for the telescopic compensation of thermal expansions of the first device (2), the second device (3) and the coupling device (1) along an axial extent (5) of the flow channel (4) while maintaining the fluidic coupling, the coupling device (1) comprising - a standpipe device (6) with a standpipe section (8) and with a first sub-channel (9) which can be fluidically coupled to the first device (2), wherein the first sub-channel (9) is delimited by an inner surface (13), and - a dip tube device (7) with a second sub-channel (11) which can be fluidically coupled to the second device (3), wherein a dip tube section (10) of the dip tube device (7) has an outer surface (12) and is telescopically received in sections in the standpipe section (8) in the first sub-channel (9), wherein the flow channel (4) is formed by the first sub-channel (9) and the second sub-channel (11), characterized in that the standpipe device (6) comprises a clamping device (15) in a distal first end region (14) of the standpipe section (8).

2. Coupling device (1) according to claim 1, characterized in that the clamping device (15) is designed as a radially circumferential tempering element (15).

3. Coupling device (1) according to claim 2, characterized in that the radially circumferential tempering element (15) comprises a heating and cooling device (16) or a heating device (17) and cooling fins (18).

4. Coupling device (1) according to one of the preceding claims, characterized in that the dip tube section (10) of the dip tube device (7) is formed from a second material, wherein the second material has a higher thermal expansion coefficient than a first material of the standpipe section (8) of the standpipe device (6).

5. Coupling device (1) according to one of the preceding claims, characterized in that a circumferential groove (20) is formed between the first end region (14) of the standpipe section (8) and a remaining region of the standpipe section (8) facing the first device (2).

6. Coupling device (1) according to one of the preceding claims, characterized in that the standpipe device (6) in the standpipe section (8) outside the first end region (14) can be heated by means of a circumferential heating element (21).

7. Coupling device (1) according to one of the preceding claims, characterized in that the standpipe device (6) in the standpipe section (8) comprises a bushing (22) made of a ceramic material or with a ceramic coating, which bushing surrounds the first partial channel (9).

8. Coupling device (1) according to one of the preceding claims, characterized in that the dip tube device (7) in the dip tube section (10) has circumferential grooves (23) or depressions spaced apart in the axial extension (5) starting from the outer surface (12) of the dip tube device (7) in the dip tube section (10).

9. Coupling device (1) according to one of the preceding claims, characterized in that the second partial channel (11) of the dip tube device (7) widens continuously in a distal second end region (24) of the dip tube section (10) towards the inner surface (13) of the first partial channel (9), wherein a distal end (25) of the dip tube device (7) is undercut by a radially circumferential recess (26) starting from the outer surface (12) of the dip tube device (7), so that the distal end (25) of the dip tube device (7) is designed as an elastic sealing lip (27) which bears against the inner surface (13) of the first partial channel (9) and which radially circumferentially extends.

10. Coupling device (1) according to one of the preceding claims, characterized in that the dip tube device (7) in the dip tube section (10) has a transition fit or a clearance fit relative to the standpipe device (6) in the standpipe section (8) at room temperature, in particular at.

11. Coupling device (1) according to one of the preceding claims, characterized in that the coupling device (1) comprises a control or regulating device with at least one sensor for directly or indirectly determining a fit between the outer surface (12) and the inner surface (13) and / or for directly or indirectly determining the stress state of the distal first end region (14) and / or for determining a difference between the diameter of the dip tube device (7) on the outer surface (12) and the diameter of the standpipe device (6) on the inner surface (13), wherein furthermore at least the tempering element (15) can be controlled and regulated by means of the control or regulating device.

12. Coupling device (1) according to claim 11, characterized in that the sensor is an optical distance sensor, a voltage sensor or a pressure sensor.

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