Heating device for a tire curing press, tire curing press, and method for manufacturing tires

Abstract

The invention relates to a heating device for a tire curing press, a tire curing press comprising a heating device, and a method for manufacturing tires. According to the invention, the heating device includes a heater and a circulation pump outside the bellows of a tire curing press, the circulation pump allowing a heat transfer medium to be circulated through a circulation pipe and the bellows of the tire curing press. The heating device additionally includes a bypass pipe such that even during process steps in which the heat transfer medium is not circulated through the bellows, the heat transfer medium can be stored in a tank pipe while continuing to be circulated through the heater in order for the desired process temperature to be maintained.

Description

[0001] Heating device for a tire heating press, tire heating press and method for producing tires

[0002] The invention relates to a heating device for a tire heating press.

[0003] Furthermore, the invention relates to a tire heating press with at least one vulcanization chamber and at least one bellows as well as at least one heating device for vulcanizing a tire in the at least one vulcanization chamber.

[0004] Furthermore, the invention relates to a method for producing tires using such a tire heating press.

[0005] Tire curing presses typically have at least one vulcanization chamber in which a green tire is formed and vulcanized using molds and pressure. Vulcanizing the tire requires heating. For this purpose, heat energy is applied to the green tire.

[0006] Various heating systems are already known for supplying heat energy to the tire. Traditionally, this is achieved by supplying a heat transfer medium, such as hot steam, to the mold area (external heating) and / or to the interior of the tire being vulcanized (internal heating).

[0007] Many designs of tire curing presses feature a bellows that expands inside the vulcanization chamber inside the tire to be vulcanized. The bellows allows the tire to be vulcanized to be pressed into the mold or mold segments arranged around the tire in the vulcanization chamber. In known designs of an internal heater, a heat transfer medium, such as hot steam, is introduced into the bellows under pressure, heating the tire to be vulcanized from the inside. Electric internal heaters are also already known, particularly in the form of heating elements arranged in the bellows in combination with a fan.

[0008] Water and a large amount of energy are required to generate hot steam. Therefore, the use of inert gas, particularly nitrogen, as an alternative heat transfer medium, either alone or in combination with hot steam, is already known.

[0009] In conventional heating systems for tire curing presses, a new supply of heated heat transfer fluid is required for each new vulcanization run. This requires time and energy, making the vulcanization process long and energy-intensive.

[0010] It is therefore an object of the invention to provide a heating device for a tire heating press which at least partially eliminates the above-mentioned problems.

[0011] This object is achieved according to the invention by a heating device for a tire heating press according to patent claim 1.

[0012] It is a further object of the invention to provide a tire heating press which at least partially overcomes the above-mentioned problems.

[0013] This object is achieved according to the invention by a tire heating press according to patent claim 9.

[0014] It is a further object of the invention to provide a method for producing tires using a tire curing press which at least partially overcomes the problems mentioned above.

[0015] This object is achieved according to the invention by a method for producing tires according to patent claim 10.

[0016] Advantageous aspects of the invention are claimed in the dependent claims.

[0017] The features of a heating device for a tire curing press, a tire curing press, and a method for producing tires disclosed below are part of the invention in all feasible combinations. A heating device for a tire curing press according to the invention comprises at least one heat transfer source, for example, a connection to a supply line and / or a pressure accumulator, at least one heater, at least one circulation pump, at least one pressure control device, at least one circulation line, and at least one bypass line.

[0018] The circulation line is preferably designed for connection to the bellows of a tire heating press such that the heat transfer medium can be passed through the bellows and circulated in the circulation line.

[0019] The heater and the circulation pump are arranged outside the bellows of a connected tire heating press in the circulation line so that the heat transfer medium can be circulated through the heater.

[0020] In embodiments of the invention, the circulation pump is designed to convey the heat transfer medium with a volume flow of approximately 200 l / min at a pressure of 28 bar.

[0021] In preferred embodiments of the invention, the heater is designed as an electric heater. In other embodiments of the invention, other types of heaters, for example, implemented using heat exchangers, can also be used alone or in combination with an electric heater.

[0022] For connection to the bellows of a tire heating press, the heating device has a connection device that provides at least two connections.

[0023] The bypass line is connected to the circulation line in such a way that the section of the circulation line extending through the bellows when connected to a tire curing press can be bypassed.

[0024] The heating device preferably has at least one controllable bypass valve and at least two controllable circulation valves. The bypass valve is arranged in the bypass line, so that the bypass line can be opened or closed using the bypass valve. The circulation valves are arranged between the connection of the bypass line and the connection device for connecting the heating device to the tire heating press, so that the part of the circulation line that passes through the bellows in a connected state can be opened or closed using the circulation valve, while the remaining part of the circulation line, in conjunction with the bypass line, forms a closed second circulation line for idle operation.

[0025] The second circulation line thus forms a reservoir or reservoir line for the heat transfer medium, in which it can be stored at an adjustable temperature with the help of the circulation pump and the heater.

[0026] The circulation pump and the heater are arranged in the part of the circulation line assigned to the second circulation line.

[0027] This heating device design allows the heat transfer medium to be kept at the required temperature even during phases of the manufacturing process where it is not needed in the bladder. This is the case, for example, before and after the tire forming and vulcanization steps, when the bladder is compressed or contracted, and the green tire is inserted into the vulcanization chamber or the vulcanized tire is removed from it. This reduces the time required to heat the heat transfer medium.

[0028] Depending on the volume of the second circulation line, the heat transfer medium can also be kept available in sufficient quantities so that the heat energy required for vulcanization of the tire is available even more quickly.

[0029] In advantageous embodiments of the invention, at least one heat carrier storage device is integrated into the second circulation line so that the amount of heat carrier kept at the required temperature can be increased.

[0030] In preferred embodiments of the invention, the heat transfer medium is formed as an inert gas, particularly preferably as nitrogen.

[0031] In embodiments of the invention, the pressure control device is implemented using a modulation valve and a pressure measuring device.

[0032] In embodiments of the invention, at least one cooling device for cooling the heat transfer medium is integrated into the circulation line. With the aid of the cooling device, the heat transfer medium can be cooled, for example, after vulcanization has taken place, so that the vulcanized tire can be removed more quickly from the vulcanization chamber or mold. In embodiments of the invention, the cooling device comprises a heat exchanger with which the heat transfer medium can be cooled, for example, using cooling water or air.

[0033] In advantageous embodiments of the invention, at least one temperature sensor is integrated into the circulation line, so that temperature control is realized with the help of the temperature measurement and the heating.

[0034] In embodiments of the invention, at least one drain valve is integrated into the circulation line, with which the pressure in the circulation line can be reduced.

[0035] The at least one heat transfer source is preferably connected to the circulation line via at least one inlet valve.

[0036] Particularly preferably, the circulation line is connected to at least two heat transfer sources, each providing the heat transfer medium at a different pressure. For example, a first heat transfer source is provided with a pressure of approximately 3 bar, and a second heat transfer source with a pressure of approximately 28 bar. The lower pressure can be used to expand the bellows and perform the molding step, while the pressure for the vulcanization step can be adjusted to the desired higher value using the 28-bar heat transfer source.

[0037] In embodiments of the invention, the circulation line is connected via at least one drain valve to at least one drain for the heat transfer medium or a heat transfer medium sink, via which the heat transfer medium can be drained after completion of the vulcanization, so that the bellows can be contracted.

[0038] In embodiments of the invention, the circulation line is connected to a vacuum line via a valve. Using such a vacuum line, the bellows and / or the circulation line can be emptied as needed.

[0039] The at least one heating device can be connected to a tire heating press in such a way that at least one internal heating device can be realized, with which a heat transfer medium can be heated to a predetermined temperature and passed through the bellows of the tire heating press, so that the tire to be vulcanized can be heated from the inside through the bellows.

[0040] In embodiments of the invention, the heating device additionally comprises an external heater. In embodiments of the invention, at least one intermediate storage device is connected to the circulation line via a valve such that the heat transfer medium can be emptied from the circulation line and / or the bellows into the latter and temporarily stored therein.

[0041] This makes it possible to reuse the heat transfer medium in a subsequent vulcanization process cycle or another tire manufacturing process.

[0042] In advantageous embodiments, at least one mechanical safety valve, a flow measuring device and / or a device for testing for leaks are integrated into the circulation line.

[0043] In embodiments of the invention, a heating device according to the invention is used as an internal and / or external heater of a tire heating press.

[0044] A tire heating press according to the invention has at least one vulcanization chamber, at least one bellows and at least one heating device according to the invention.

[0045] The bellows is arranged centrally in the closed vulcanization chamber and is expandable in such a way that a tire to be vulcanized can be pressed from the inside into a mold arranged in the vulcanization chamber.

[0046] In embodiments of the invention, the mold consists of several mold segments.

[0047] The heating device according to the invention is connected to the bellows of the tire heating press in such a way that it forms part of the circulation line and thus an internal heating system is realized.

[0048] In embodiments of the invention, the heating device according to the invention additionally provides external heating of the tire heating press.

[0049] In embodiments of the invention, the tire heating press comprises a post-treatment device for post-treating vulcanized tires, wherein the post-treatment device is connected to the at least one intermediate storage device of the heating device for utilizing the intermediately stored heat carrier.

[0050] A method according to the invention for producing tires using a tire heating press comprises at least the following process steps:

[0051] Loading a vulcanization chamber of the tire heating press with a green tire, closing the vulcanization chamber,

[0052] Expanding the bellows of the tire curing press by introducing inert gas, vulcanizing the green tire to form a tire, opening the vulcanization chamber, contracting the bellows, and discharging the vulcanized tire from the vulcanization chamber, wherein, at least during the vulcanization process step, an inert gas is circulated as a heat transfer medium through a circulation line and the bellows, wherein the inert gas is circulated and heated by means of a circulation pump and heater arranged in the circulation line outside the bellows to realize internal heating of the tire curing press, and wherein, in at least one further process step of tire production, the part of the circulation line connected to the bellows is bypassed by means of a bypass line so that no inert gas is circulated through the bellows,but the heat transfer medium is circulated through the heater in a reservoir line formed from the remaining part of the circulation line and the bypass line with the help of the circulation pump.

[0053] The process temperature required for vulcanization is adjusted by circulating the inert gas through the heater located outside the bellows, with the inert gas being used as a heat carrier.

[0054] The inert gas nitrogen is preferably used as the heat transfer medium.

[0055] Particularly preferably, the temperature of the inert gas is set to a desired value in a reservoir before the expansion of the bellows, so that inert gas of the desired temperature is available from the beginning for the expansion of the bellows and the subsequent vulcanization process.

[0056] In preferred embodiments of the method according to the invention, a tire heating press according to the invention is used.

[0057] Preferably, the pressure and / or temperature of the inert gas is regulated.

[0058] An example of the procedure is described below.

[0059] The inert gas is fed into the circulation line of the heating device via an inert gas source, in particular a nitrogen source, and heated by the heater. The heater is preferably designed to heat nitrogen from approximately room temperature (approximately 20°C) to a temperature of up to 200°C in a single pass.

[0060] The pressure and temperature are adjusted for the process steps of forming (expansion of the bellows) and vulcanization.

[0061] The pressure is adjusted, for example, using a modulation valve and a pressure measuring device.

[0062] As soon as the target pressure in the bellows is reached, the heater begins to circulate the inert gas through the circulation line and the integrated bellows with the aid of the pump. The heat transferred from the heat transfer medium to the tire being vulcanized, as well as other heat losses, are compensated for by the continuous circulation of the inert gas through the heater.

[0063] This makes it possible to achieve a very even heat distribution in the bellows.

[0064] After the tire vulcanization is completed, the bellows is contracted and the bypass valve and circulation valves are switched so that the inert gas circulates in the reservoir line.

[0065] Typical values ​​for process pressure and heat transfer medium temperature in the various possible process steps are 105°C at 1.5 bar in the forming step (bellows expansion), 200°C at 28 bar in the vulcanization step, and 50°C at 5 bar for the optional active cooling after vulcanization. These values ​​are derived from the tire vulcanization process using steam and are therefore determined by the vapor pressure curve. Other temperature / pressure values ​​can also be adjusted using nitrogen as the heat transfer medium.

[0066] The invention makes it possible to approach any point in the pressure-temperature characteristic curve for heating and pressurizing the bellows from the very beginning. This enables new and faster process steps in tire manufacturing. Steam and its generation are also preferably completely eliminated. This not only means significant energy savings but also completely eliminates water waste.

[0067] Embodiments of the invention are illustrated by way of example in the following drawings. They show: Figure 1: A schematic block diagram of the heating device of a heating device according to the invention.

[0068] tire heating press,

[0069] Figure 2: a schematic block diagram of a heating device with buffer storage,

[0070] Figure 3: a schematic block diagram of a heating device with an intermediate storage device connected to an aftertreatment device.

[0071] The heating device (1) shown in Figure 1 has a circulation line (2), a bypass line (3), a heater (4) and a circulation pump (5).

[0072] The circulation line (2) is connected to the bellows (31) of a tire heating press via a connecting device (18) in such a way that the interior of the bellows (31) is integrated into the circulation line (2).

[0073] The heating device (1) has two heat transfer medium sources (7), wherein a first heat transfer medium source (7) provides nitrogen at a pressure of 28 bar and a temperature of 20°C, and a second heat transfer medium source (7) provides nitrogen at a pressure of 3 bar and a temperature of 20°C. By opening the respectively assigned supply valve (21), the heat transfer medium, selected here as nitrogen, can be admitted from the respective heat transfer medium source (7) into the circulation line (2).

[0074] The circulation line (2) can be functionally divided into two sections, whereby the sections are separated from each other by the connection points of the bypass line (3) on the circulation line (2).

[0075] At least one bypass valve (13) is integrated into the bypass line (3). When the bypass valve (13) is closed, the heat transfer fluid circulates through the circulation line (2) and the bellows (21).

[0076] If the bypass valve (13) is opened and the circulation valves (14), which are arranged in the part of the circulation line (2) facing the connection device (18) downstream of the connection points of the bypass line (3), are closed, the heat transfer medium circulates in the reservoir line (6) formed by the bypass line (3) and the remaining part of the circulation line (2). The circulation pump (5) and the heater (4) are arranged in the reservoir line (6), so that the heat transfer medium can only be heated in the reservoir line (6), even during circulation.

[0077] In embodiments of the invention, the volume of the reservoir line (6) can be expanded by a storage device (10).

[0078] In embodiments of the invention, the flow in the circulation line (2) can be measured by means of a flow measuring device (22).

[0079] If heat transfer fluid is to be drained from the heating device (1) and / or the bellows (31), this can be done via heat transfer fluid sinks (8). If multiple heat sinks (8) are provided, they can be designed for different pressure ranges.

[0080] The pressure in the circulation line (2) can be measured using a pressure measuring device (15). The temperature can be measured at at least one point in the circulation line (2) and / or in the bellows (31) using at least one temperature sensor (16).

[0081] In the illustrated embodiment of the invention, a cooling device (17) is integrated into the circulation line (2). This is optional and serves to cool the heat transfer medium.

[0082] Heat transfer fluid can be drained from the circulation line (2) via a safety drain (19) using a safety valve (20) if this should be necessary for safety reasons.

[0083] According to the embodiment in Figure 2, the heating device (1) shown in Figure 1 is extended by an intermediate storage (23), optionally by two intermediate storages (23), which can be connected to or separated from the circulation line (2) via a valve (11).

[0084] The intermediate reservoir (23) is designed as a pressure accumulator. A suitable pressure range for the pressure accumulator is, for example, 1 to 30 bar.

[0085] The intermediate storage tank (23) enables the heat transfer medium to be emptied from the circulation line (2) and / or the bellows (31) into it, instead of removing it via a heat transfer medium sink (8) or the vacuum system (9).

[0086] The heat transfer medium is temporarily stored under pressure in the intermediate storage unit (23). This allows the heat transfer medium to be reused for subsequent process cycles, in particular a subsequent vulcanization process, or for other tire manufacturing processes.

[0087] In addition to the reduced energy consumption for heating the heat transfer medium to the required process temperature, depending on the residual heat present in the temporarily stored heat transfer medium, the use of temporarily stored heat transfer medium also saves the costs and effort for purchasing or producing new heat transfer medium or for applying the required process pressure to the heat transfer medium.

[0088] Figure 3 shows a system according to the invention with a post-treatment device (40). Post-treatment devices (40) are used in tire production after vulcanization, for example, to cool the still-hot tires under controlled conditions.

[0089] In certain post-treatment devices (40), the vulcanized tires are subjected to internal pressure. Compressed air is required for this.

[0090] The heat transfer medium from a heating device (1) according to the invention, which is temporarily stored in an intermediate storage (23), has a sufficient pressure for the after-treatment of the tires.

[0091] In the illustrated embodiment of the invention, the aftertreatment device (40) has two aftertreatment stations (41, 42). The compressed air device (43) of the aftertreatment device (40) is connected to the at least one intermediate storage device (23), so that the intermediately stored heat transfer medium can be used for the aftertreatment of the tires.

[0092] In the embodiment of the invention shown, the aftertreatment pressure can be adjusted by means of a modulation valve (12).

Claims

Patent claims 1. A heating device (1) for a tire curing press, comprising at least one heat transfer medium source (7), at least one heater (4), at least one circulation pump (5), at least one pressure control device, at least one circulation line (2), and at least one bypass line (3), wherein the heating device (1) is connectable to a tire curing press in such a way that at least one internal heater can be realized, with which a heat transfer medium can be heated to a predetermined temperature and passed through the bellows (31) of the connected tire curing press, so that the tire to be vulcanized can be heated from the inside through the bellows (31), characterized in that the heater (4) and the circulation pump (5) are arranged outside the bellows (31) of a connected tire curing press in the circulation line (2), so that the heat transfer medium can be circulated through the heater (4), and that the bypass line (3) is connected to the circulation line (2) in such a way thatthat the section of the circulation line (2) extending through the bellows (31) in a state connected to a tire heating press can be bypassed., 2. Heating device (1) according to claim 1, characterized in that the heater (4) is designed as an electric heater.

3. Heating device (1) according to one of the preceding claims, characterized in that it has at least one controllable bypass valve (13) and at least two controllable circulation valves (14), wherein the bypass valve (13) is arranged in the bypass line (3) so that the bypass line (3) can be opened or can be closed, and wherein the circulation valves (14) are arranged between the connection of the bypass line (3) to the circulation line (2) and the connections of the connection device (18) for connecting the heating device (1) to the tire heating press, so that the part of the circulation line (2) which passes through the bellows (31) in a connected state can be opened or closed by means of the circulation valves (14), while the remaining part of the circulation line (2) in connection with the bypass line (3) forms a reservoir line (6).

4. Heating device (1) according to claim 3, characterized in that at least one heat medium storage device (10) is integrated into the reservoir line (6), so that the reservoir volume is increased.

5. Heating device (1) according to one of the preceding claims, characterized in that the heat carrier is designed as an inert gas.

6. Heating device (1) according to one of the preceding claims, characterized in that the heat transfer medium is designed as nitrogen.

7. Heating device (1) according to one of the preceding claims, characterized in that at least one cooling device (17) for cooling the heat transfer medium is integrated into the circulation line (2).

8. Heating device (1) according to one of the preceding claims, characterized in that it has at least one intermediate storage device (23) which is connected to the circulation line (2) via a valve (11) in such a way that the heat transfer medium from the circulation line (2) and / or the bellows (31) of a connected tire heating press can be emptied into the latter and temporarily stored therein.

9. Tire heating press comprising at least one vulcanization chamber (30) and at least one bellows (31), characterized in that it comprises at least one heating device (1) according to one of claims 1 to 8, wherein the bellows (31) is connected to the circulation line (2).

10. A method for producing tires using a tire curing press comprising at least the following process steps: a. Loading a vulcanization chamber (30) of the tire curing press with a green tire, b. Closing the vulcanization chamber (30), c. Expanding the bellows (31) of the tire curing press by introducing inert gas, d. Vulcanizing the green tire to form a tire, e. Opening the vulcanization chamber (30), f. Contracting the bellows (31), g.Unloading the vulcanized tire from the vulcanization chamber (30), wherein at least during the vulcanization process step, an inert gas is circulated as a heat transfer medium through a circulation line (2) and the bellows (31), wherein the inert gas is circulated and heated by means of a circulation pump (5) and heater (4) arranged in the circulation line (2) outside the bellows (31) to realize an internal heating of the tire heating press, and wherein in at least one further process step of the tire production, the part of the circulation line (2) connected to the bellows (31) is bypassed by means of a bypass line (3) so that no inert gas is circulated through the bellows (31), but rather the heat transfer medium is circulated through the heater (4) in a reservoir line (6) formed from the remaining part of the circulation line (2) and the bypass line (3) by means of the circulation pump (5).

11. A process for producing tires according to claim 10, characterized in that nitrogen is used as the heat carrier.

12. A method for producing tires according to one of claims 10 and 11, characterized in that the temperature of the inert gas is set to a desired value in a reservoir before the expansion of the bellows (31), so that inert gas of the desired temperature is available from the beginning for the expansion of the bellows (31) and the subsequent vulcanization process.

13. A method for producing tires according to any one of claims 10 to 12, characterized in that a tire heating press according to claim 9 is used.

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