Electrically driven heater for steam-heated consumers

Abstract

The invention relates to an electrically driven heater (1) for steam-heated consumers (2), comprising: a fluid storage vessel (3) for receiving a fluid; a fluid-heated mould (5); and a pipe connection (4) between the fluid storage vessel (3) and the fluid-heated mould (5); and a temperature sensor (17) and / or a pressure sensor; and a heating means (19), which thermally interacts with the fluid and can be operated by means of electrical energy.

Description

[0001] Description

[0002] Electrically driven heating for steam-heated consumers

[0003] The invention relates to an electrically driven heater for steam-heated consumers with a fluid storage vessel for receiving a fluid and a piping of the fluid storage vessel with a fluid-heated mold and a temperature sensor and / or pressure sensor and a heating medium which is in thermal interaction with the fluid and can be operated by means of electrical energy.

[0004] Furthermore, the invention relates to a method for operating such an electrically driven heater.

[0005] An electrically driven heater with a fluid-heated mold, for example for heating tire curing presses, is known. These have a central boiler for generating steam, which is typically connected to a large number of tire curing presses via piping. It has proven disadvantageous to use one boiler for a large number of steam-heated consumers, or even to use just one boiler for several heating chambers, for example, in a tire curing press, as this results in significant piping costs. Furthermore, the piping requires maintenance, with flexible piping requiring increased maintenance. The piping takes up considerable space and therefore limits the design of the steam-heated consumers. Furthermore, the piping leads to energy losses during operation due to its heat dissipation, thus reducing efficiency.

[0006] Furthermore, decentralized electrically driven heaters are known, which, however, are not intended for heating a fluid-heated mold, but rather for heating the bellows of a tire curing press. Compared to the heater according to the invention, such heaters are more costly to manufacture and require more maintenance during operation. Known heaters for heating bellows are designed for cyclical operation and must be capable of being depressurized; they must be designed for pressures of approximately 25 bar. To achieve this pressure, the heaters have a pressure-increasing component such as a compressor. Bellows are subject to wear, so that bellows components can enter the fluid, and the heater must be equipped with filters and, in addition, be designed to be removable for regular maintenance.

[0007] A consumer not heated by steam, for example, one heated directly by electricity, has proven to be disadvantageous in terms of heat distribution and is far more complex and error-prone in terms of control and regulation to adjust the heat flow. Another disadvantage of such a consumer is that retrofitting existing consumers requires significantly more complex adjustments. Known processes would have to be re-evaluated and approved, which may require new sampling by the customer.

[0008] Against this background, the invention is based on the object of designing a steam-heated consumer and a method of the type mentioned at the outset which requires little installation space in such a way that the expenditure on manufacturing and maintenance of the electrically driven heater is reduced, whereby less installation space is required by means of piping and the energy consumption during use is to be reduced.

[0009] These objects are achieved by a device according to the features of patent claim 1 and a method for operating the electrically driven heater according to the independent claim. The subclaims relate to particularly useful developments of the invention.

[0010] These objects are achieved with a device according to the features of patent claim 1 and a method for operating the electrically driven heater according to the independent claim. The subclaims relate to particularly expedient developments of the invention. According to the invention, an electrically driven heater for steam-heated consumers is provided, comprising a fluid storage vessel for holding a fluid, a fluid-heated mold, and piping connecting the fluid storage vessel to the fluid-heated mold, as well as a temperature sensor and / or pressure sensor, and a heating means that thermally interacts with the fluid and can be operated using electrical energy, wherein the fluid storage vessel, the temperature sensor and / or pressure sensor, and the heating means that can be operated using electrical energy are mounted in the immediate vicinity of the fluid-heated mold.

[0011] Attaching the electric heater to the fluid-heated mold allows for shorter piping runs, thus reducing piping and maintenance costs and the space required for the piping. Enabling shorter piping runs reduces heat loss through the piping and increases the efficiency of the electrically driven heater.

[0012] A fluid-heated mold is a rigid mold, made of metal, for example. A rigid mold has the advantage over a flexible mold such as a bellows in that it can be permanently pressurized, allowing for a particularly cost-effective and compact electrically driven heater. Furthermore, a rigid mold is subject to less wear than a flexible mold when pressurized, especially during pressure fluctuations.

[0013] Thermal interaction means that heat can be transferred in a high and efficient manner. For this purpose, the electrically powered heating medium can be in direct contact with the fluid or thermally connected to the fluid, for example, through a heat exchanger or a conductive connection.

[0014] By being mounted in the immediate vicinity of the fluid-heated mold is meant that the fluid storage vessel, the temperature sensor or pressure sensor and the heating means operable by means of electrical energy are mounted on the fluid-heated mold or are at least not more than 10 meters, preferably not more than 5 meters, away from the mold.

[0015] In particular, for existing steam-heated consumers, it is still advantageous not to create any changed conditions, since otherwise procedures for existing products would have to be re-evaluated and, if necessary, approved.

[0016] A preferred embodiment provides that the steam-heated consumer is a tire curing press, in particular tread segments and / or an upper heating plate and / or a lower heating plate of the tire curing press. An electrically driven heater according to the invention is particularly advantageous for tire curing presses, since tire curing presses are regularly arranged in large numbers next to one another, thus requiring complex and extensive piping.

[0017] A preferred embodiment provides for the piping to have a flexible section for assembly purposes, while the other sections of the piping are rigid. The flexible section of the piping makes it easy to use an electrically driven heater, for example, on differently sized conical ring containers, thus enabling flexibility in production.

[0018] A preferred embodiment provides for the electrically driven heater to be mounted immovably to the fluid-heated mold. This immovable mounting eliminates the need for flexible piping. These are necessary in known electrically driven heaters to enable the fluid-heated molds to be movable.

[0019] A preferred embodiment provides that the heating means operable by means of electrical energy is a heating coil and / or an induction generator, which preferably inductively heats a wall of the fluid storage vessel, and / or a combined heat and power engine, in particular a heat pump. The use of a heating coil enables a particularly cost-effective implementation of an electrically operated heating means. However, it has been found that an induction generator has a high durability and is also particularly easy to maintain, since it can be replaced without opening the fluid system. Furthermore, a high power transmission density is thus enabled using a particularly compact heating means. Combined heat and power engines have proven to be particularly efficient in terms of energy consumption.

[0020] A preferred embodiment provides for the electrically operated heater to have a valve circuit consisting of several valves, the actuation of which enables the fluid to be conveyed through the fluid-heated mold using steam pressure. Such a valve circuit eliminates the need for a conveying means for conveying the fluid, thereby saving costs and space and increasing the energy efficiency of the electric heater.

[0021] A preferred embodiment provides for the electric heater to have a condensate tank. A condensate tank allows for a simple valve circuit for conveying the fluid using steam pressure.

[0022] A preferred embodiment provides for a fourth switchable valve on a discharge line from the fluid-heated mold, a fifth switchable valve on a liquid-phase line from the condensate vessel to the fluid storage vessel, and a second switchable valve on a vapor-phase line between the fluid storage vessel and the condensate vessel. This valve circuit enables, in a simple manner, a vapor flow into the fluid-heated mold and a condensate flow into the condensate vessel in a first switching position of the valves, while a gravity-driven backflow of the condensate from the condensate vessel into the fluid storage vessel is enabled in a second switching position of the valves. A preferred embodiment provides for the electrically driven heater to be designed for an operating pressure of less than 12 bar, thereby enabling a particularly cost-effective and compact implementation of the heater.

[0023] A preferred embodiment provides for the electrically driven heater to have a pump for conveying the fluid. This can, for example, accelerate the return of the condensate to the fluid storage vessel and allow for more flexibility in the arrangement of the fluid storage vessel relative to the condensate vessel. Furthermore, the valve circuit can be simplified.

[0024] A preferred embodiment provides that the electrically driven heater is designed for continuous operation, whereby continuous operation is understood in particular to mean a substantially constant pressure, although process-related fluctuations may occur. However, at least a permanent overpressure of greater than one bar relative to the ambient temperature is maintained. Furthermore, the temperature is preferably kept substantially constant.

[0025] A preferred embodiment provides for the electrically driven heater to be a closed system, so that no volume flow is exchanged with the environment. This enables a particularly reliable and low-maintenance electrically driven heater.

[0026] A preferred embodiment provides that the fluid comprises or consists of water, or is a heat transfer oil or a refrigerant. Water as a fluid has proven advantageous in terms of procurement and disposal and, moreover, has a high enthalpy of vaporization. Heat transfer oils have proven advantageous due to their low oxidation rate in metals and their ability to operate at high temperatures and low pressures. Refrigerants as a fluid offer the advantage that an additional fluid and heat exchanger are not required when using a combined heat and power engine.

[0027] A preferred embodiment provides for the electrically operated heater to have a vent valve and / or a safety valve. This allows for easy venting of the electrically operated heater and allows for simple commissioning and safe operation of the electrically operated heater.

[0028] A preferred embodiment provides for the fluid storage vessel and the piping to be sections of a heat pipe. Configuring the fluid storage vessel and the piping as sections of a heat pipe enables simple implementation of the electrically operated heater, since the steam is driven by steam pressure, and the condensate is conveyed back to the electrically operated heating element by gravity and / or capillary forces. Valves and a pump can be omitted.

[0029] A preferred embodiment provides for the electrically operated heater to be mounted immovably to the fluid-heated mold. This immovable mounting eliminates the need for flexible piping. These are necessary in known electrically operated heaters to enable the fluid-heated molds to be moved.

[0030] According to the invention, a method for operating the electrically driven heating system of a steam-heated consumer is provided, wherein the measured values ​​of a temperature sensor and / or a pressure sensor are compared with target values, and the heating output of an electrically driven heating means is adjusted to bring the measured value closer to the target value. A simple and efficient method for operating a steam-heated consumer is enabled. A preferred embodiment provides for the condensate to be pumped into a steam generating vessel by a pump. A high and constant delivery rate of the condensate is enabled.

[0031] A preferred embodiment provides that the condensate is pumped into a condensate vessel by steam pressure in a first step and into a fluid storage vessel in a second step by actuating valves. The process can thus be operated without actively pumping the fluid, making it particularly efficient.

[0032] According to the invention, a use of an inventive electrically driven heater for heating a steam-heated consumer, in particular for carrying out an inventive method, is provided.

[0033] The invention permits numerous embodiments. To further clarify its basic principle, two of them are shown in the drawings and are described below. These show in

[0034] Fig. 1 shows an electrically driven heater for a tire heating press with a fluid storage vessel during steam generation;

[0035] Fig. 2 an electrically driven heater for a tire heating press with a fluid storage vessel for condensate recovery;

[0036] Fig. 3 an electrically driven heater for a tire heating press with a fluid reservoir and a pump.

[0037] Figure 1 shows an electrically driven heater 1 for a tire heating press 2 with a fluid reservoir 3 for steam generation. The electrically driven heater 1 is connected to the fluid reservoir 3, which has an electrically operated heating medium 19, via rigid piping 4 to a fluid-heated mold 5 in the form of a conical ring container of a tire heating press 2. Only a flexible section 6 of the piping 4 is provided for mounting the electrically driven heater 1 on differently dimensioned steam chambers in the conical ring container.

[0038] The conical ring container has a recess 7 for receiving the water vapor generated by the electrically driven heater 1, which is supplied to it via the piping 4. In the recess 7, the water vapor releases heat to the conical ring container, condenses, and collects in the lower area of ​​the recess 7. The further water vapor flow transports the resulting condensate against the force of gravity g through the piping 4 into a condensate vessel 8, which is arranged above the fluid storage vessel 3 with respect to the force of gravity g.

[0039] The condensate vessel 8 is connected via a 3 / 2-way valve 9 to a safety valve 10, a vent valve 11 and a blocking first switchable valve 12 for maintenance purposes.

[0040] The condensate vessel 8 for the conduction of steam is connected to the fluid storage vessel 3 via a second switchable valve 13 which is switched to a blocking position and together with the piping 4.

[0041] A third, conductively switched, switchable valve 14 is arranged between the fluid storage vessel 3 and the conical ring container. The switchable valve 14 serves, when the valve is closed, for example, to calibrate a temperature sensor 17 installed in the fluid storage vessel 3. Furthermore, the switchable valve 14 can also be closed during operation in order to briefly achieve a somewhat higher pressure in the steam generator. Furthermore, a fourth, conductively switched, switchable valve 15 is arranged between the conical ring container and the condensate vessel 8, and a fifth, non-conductively switched, switchable valve 16 is arranged between the condensate vessel 8 and the fluid storage vessel 3, for returning the water to the fluid storage vessel 3.In these switching positions of the switchable valves 13, 14, 15, 16, the water vapor generated in the fluid storage vessel 3, the temperature of which is measured by the temperature sensor 17, is conveyed by the vapor pressure into the recess 7 and from there as condensate into the condensate vessel 8.

[0042] Once a sufficient amount of condensate has been pumped into the condensate vessel 8, the fourth switchable valve 15 is closed and the second switchable valve 13 and the fifth switchable valve 16 are opened. No further condensate is fed into the condensate vessel 8. The condensate is pumped from the condensate vessel 8 into the fluid storage vessel 3 by gravity g. Figure 2 shows the electrically driven heater 1 of Figure 1 for a tire curing press 2 with a fluid storage vessel 3 during condensate recovery with this circuit of the switchable valves 13, 14, 15, 16.

[0043] Once the water has been pumped back into the fluid storage vessel 3, the switching of the switchable valves 13, 14, 15, 16 shown in Figure 1 is carried out and the process starts again.

[0044] Figure 3 shows an electrically driven heater 1 for a tire heating press 2 with a fluid reservoir 3 and a pump 18. The tire heating press 2 corresponds to that shown in Figure 1. The electrically driven heater 1 is an alternative embodiment to Figure 1, but can be combined with the embodiment shown in Figure 1, for example, by arranging the pump 18 between the recess 7 and the condensate vessel 8.

[0045] The electrically driven heater 1 has the fluid storage vessel 3 with the temperature sensor 17 as well as a safety valve 10, a vent valve 11, and a first switchable valve 12 connected via the 3 / 2-way valve 9. The piping 4 is rigid and has only a flexible section 6 for mounting on various conical ring containers. The pump 18 for conveying the condensate is arranged between the conical ring container and the fluid storage vessel 3. When the electrically driven heater 1 is in operation, water vapor is conveyed by its pressure from the fluid storage vessel 3 into the recess 7. There, the water vapor condenses to form condensate, which is conveyed by the pump 18 into the fluid storage vessel 3.

[0046] List of reference symbols

[0047] 1 electrically powered heater

[0048] 2 tire heating presses

[0049] 3 Fluid storage vessel

[0050] 4 Piping

[0051] 5 Fluid heated mold

[0052] 6 flexible area

[0053] 7 Recess

[0054] 8 Condensate vessel

[0055] 9 3 / 2-way valve 0 Safety valve 1 Vent valve 2 First switchable valve 3 Second switchable valve 4 Third switchable valve 5 Fourth switchable valve 6 Fifth switchable valve 7 Temperature sensor 8 Pump 9 Electrically operated heating medium g Gravity

Claims

Patent claims 1. Electrically driven heater (1) for steam-heated consumers (2) comprising a fluid storage vessel (3) for holding a fluid, a fluid-heated mold (5) and piping (4) of the fluid storage vessel (3) with the fluid-heated mold (5) and a temperature sensor (17) and / or pressure sensor and a heating means (19) which is in thermal interaction with the fluid and can be operated by means of electrical energy, characterized in that the fluid storage vessel (3) and the temperature sensor (17) and / or pressure sensor and the heating means (19) which can be operated by means of electrical energy are mounted in the immediate vicinity of the fluid-heated mold (5).

2. Electrically driven heater (1) according to claim 1, characterized in that the steam-heated consumer is a tire heating press, in particular profile segments and / or an upper heating plate and / or a lower heating plate of the tire heating press.

3. Electrically driven heater (1) according to claims 1 or 2, characterized in that the piping (4) has a flexible region for assembly purposes, the other regions of the piping (4) being rigid.

4. Electrically driven heater (1) according to one of the preceding claims, characterized in that the electrical heater (1) is suitable and / or usable for heating exactly one fluid-heated consumer at the same time.

5. Electrically driven heater (1) according to one of the preceding claims, characterized in that the heating means operable by means of electrical energy is a heating coil and / or an induction generator, which preferably inductively heats a wall of the fluid storage vessel (3) and / or a combined heat and power machine, in particular a heat pump.

6. Electrically driven heater (1) according to one of the preceding claims, characterized in that the electrical heater (1) has a valve circuit whose actuation enables the fluid to be conveyed through the fluid-heated mold (5) by means of steam pressure.

7. Electrically driven heater (1) according to one of the preceding claims, characterized in that the fluid-heated mold consists of a metal.

8. Electrically driven heater (1) according to one of the preceding claims, characterized in that the valve circuit has a fourth switchable valve (15) on a discharge line from the fluid-heated mold (5) and a fifth switchable valve (16) on a liquid phase line from the condensate vessel (8) to the fluid storage vessel (3) and a second switchable valve (13) on a vapor phase line between the fluid storage vessel (3) and the condensate vessel (8).

9. Electrically driven heater (1) according to one of the preceding claims, characterized in that the electrically driven heater (1) is designed for an operating pressure of less than 12 bar.

10. Electrically driven heater (1) according to one of the preceding claims, characterized in that the electrically driven heater (1) is designed for continuous operation.

11. Electrically driven heater (1) according to one of the preceding claims, characterized in that the electrically driven heater (1) is a closed system.

12. Electrically driven heater (1) according to one of the preceding claims, characterized in that the fluid comprises or consists of water or is a heat transfer oil or a coolant.

13. Electrically driven heater (1) according to one of the preceding claims, characterized in that the fluid storage vessel (3) and the piping (4) are partial regions of a heat pipe.

14. Method for operating an electrically driven heater (1) of a steam-heated consumer (2) according to one of claims 1 to 12, characterized in that the measured values ​​of a temperature sensor (17) and / or pressure sensor are compared with setpoint values ​​and the heating output of an electrically driven heating means (19) is adjusted to bring the measured value closer to the setpoint value.

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