WO2020064724A1

WO2020064724A1 - Clamping system of a roller mill having a modular hydraulic accumulator unit

Info

Publication number: WO2020064724A1
Application number: PCT/EP2019/075701
Authority: WO
Inventors: Rainer Westphal; Michael Textores
Original assignee: Mitsubishi Hitachi Power Systems Europe Gmbh
Priority date: 2018-09-25
Filing date: 2019-09-24
Publication date: 2020-04-02
Also published as: DE102018123508A1; DE112019004795A5

Abstract

In a clamping system (118), in particular a hydropneumatic clamping system, of a roller mill (110) having at least two cylinder units (124) that are respectively intended to apply a grinding pressure and a counter-pressure, wherein each cylinder unit (124) is assigned at least two pressure accumulator vessels (126c, 126b), namely a grinding pressure accumulator vessel (126c) and a counter-pressure accumulator vessel (126b), and a hydraulic unit arranged in the vicinity of each particular cylinder unit (124), a solution is intended to be created that makes it possible to reduce the assembly effort and the space requirement and thus the installation costs and also to optimize operation so as to reduce the operating and maintenance costs. This is achieved in that the at least one grinding pressure accumulator vessel (126c) and the at least one counter-pressure accumulator vessel (126b) are configured to be exchangeable together with the hydraulic unit, as a modular hydraulic accumulator unit (130).

Description

Clamping system of a roller mill with a modular hydraulic storage unit

The invention relates to a clamping system, in particular a hydropneumatic clamping system, a roller mill with at least two cylinder units, each designed to exert a grinding pressure and a counter pressure, each cylinder unit having at least two pressure storage containers, a grinding pressure and a counter pressure storage container, and one for the respective cylinder unit Locally arranged hydraulic unit is assigned.

Furthermore, the invention is directed to a modular hydraulic storage unit for a clamping system of a roller mill, in particular a hydropneumatic clamping system, in particular according to an embodiment of the invention.

Finally, the invention is also directed to a roller mill itself, comprising a clamping system, in particular a hydropneumatic clamping system, according to an embodiment according to the invention with a modular hydraulic storage device.

Rolling mills, in particular roller bowl mills, are used, for example, as coal mills in the field of coal-fired power plants for grinding the coal to be burned in the combustion chamber of a steam generator. The basic structure of roller mills or roller bowl mills or also vertical mills comprises a mill housing with a grinding plate arranged therein, on which the grinding tools lying thereon are pressed due to their own weight, but also by applying additional spring force or hydraulic force.

A clamping system of such a roller or roller-type bowl mill expediently has a plurality of cylinder units arranged around the grinding table and connected to a clamping frame of the roller mill, each with a storage unit. Depending on the size of the grinding tools, a cylinder unit comprises one or two, preferably double-acting, hydraulic cylinders. There is a piston within such a double-acting hydraulic cylinder recorded longitudinally movable, which divides the cylinder space into a first hydraulic chamber assigned to the annular surface of the piston and a second hydraulic chamber assigned to the opposite piston surface of the piston. By introducing hydraulic fluid into the corresponding hydraulic chambers, a grinding pressure can be exerted on the annular surface of the piston and a counter pressure can be exerted on its opposite piston surface, as a result of which the piston can be moved within the hydraulic cylinder. The piston movement resulting from the grinding pressure or back pressure to be set is transmitted to the clamping frame of the clamping system by means of an external piston rod, which in turn allows the grinding tools to be pressed onto the grinding plate or also enables the grinding tools to be lifted off the grinding plate. The storage unit assigned to a respective cylinder unit preferably comprises a plurality of bladder accumulators, at least one of which is designed as a grinding pressure storage container for supplying the annular surface of the piston with hydraulic fluid and at least one other bladder accumulator as a counterpressure storage container for loading the piston surface with hydraulic fluid.

The supply of hydraulic fluid, preferably pressure oil or hydraulic oil, to the pressure reservoir tank required to set the intended grinding pressure and back pressure, is usually carried out for all cylinder units by a single, centrally arranged hydraulic device, also called a hydraulic unit. For this purpose, several connecting lines, in particular pipelines, with a relatively large and different length to the cylinder units are necessary around the mill base, which are connected to the individual cylinder units and storage units, as well as to the centrally arranged hydraulic device, in order to supply all cylinder units and storage units one To ensure clamping system with the required hydraulic fluid. Such piping requires a high installation effort with pressure tests, the arrangement of the central hydraulic device usually being carried out on the mill foundation of the roll mill or bowl mill or in the boiler house cellar. Hydropneumatic arrangements with an integrated hydraulic device are already known from the prior art. A compact hydropneumatic compression spring arrangement for setting pressure forces exerted by the rod of a single-acting hydraulic cylinder can be found, for example, in FR 2 614 665 A1. The hydraulic cylinder itself, a hydropneumatic accumulator, the associated hydraulic control unit and the motor-pump unit are combined to form an independent, self-contained assembly. Such a compression spring arrangement is, however, unsuitable for use for a clamping system of a roller mill due to the single-acting hydraulic cylinder, since pressurization of the piston on both sides and thus force on both sides of the grinding tools would not be possible. This would not guarantee the smoothness required for the desired grinding quality, and it would also not be possible to raise and lower the grinding tools by means of the one hydraulic cylinder. Furthermore, retrofitting existing clamping systems for roller mills would entail considerable expenditure due to the cylinder unit already integrated in the hydraulic unit, or may not be possible at all.

Hydropneumatic clamping systems, in which a central hydraulic device is to be replaced by several decentralized hydraulic units assigned to the respective cylinder or storage units, are also proposed in the area of roller mills. For example, from EP 2 408 565 B1 a hydraulic arrangement of a roller mill is known, in which each grinding roller or its suspension unit is assigned its own hydraulic supply unit as a so-called compact unit, in which all the necessary supply and control components are integrated. The hydraulic supply unit is connected by means of pipes to the storage stand, which is also designed as a compact unit and is associated with the suspension unit and which has hydraulic bladder accumulator and hydraulic piston accumulator. Each suspension unit of a grinding roller is thus assigned its own hydraulic supply unit as a compact hydraulic unit and a separate storage stand designed as its own compact unit. The hydraulic supply unit should be in a straight line be arranged with the suspension unit and the associated storage stand, so that the pipelines between the hydraulic supply unit and the high-pressure hoses between the storage stand and the hydraulic cylinders are relatively short and pipe elbows can therefore be omitted. The pre-assembled compact hydraulics is still placed directly on an oil tank and can be lifted from the oil tank in a relatively short amount of time and replaced with an identical unit. A disadvantage of this embodiment is that pipes are still required to connect the compact hydraulics to the storage stand designed as a compact unit. Such pipelines must be pickled, rinsed and subjected to pressure tests, which leads to increased costs. It is also necessary to connect the compact hydraulic system to or remove it from the oil tank during installation or replacement.

A similar design of a hydropneumatic clamping system for a roller mill with a block arrangement of a storage device and a hydraulic device is known from DE 10 2010 031 442 A1. The hydraulic device and the associated, separate storage device are connected to one another via a common carrier element. One or more bores can be provided within the carrier element, which can function as connecting lines between the storage device and the hydraulic device, as a result of which corresponding pipelines and their installation can be dispensed with. The storage devices and the hydraulic devices are each designed as separate assemblies or modules, which can be assembled at the desired position when the roller mill is commissioned on the construction site. This makes it possible not only to replace an entire block, but also a single hydraulic device or a single storage device. However, this also has disadvantages. On the one hand, a relatively high assembly effort for installation on the construction site is still necessary, since the storage device and the hydraulic device are to be installed and connected individually, on the other hand, the space requirement is increased due to the common support element, which connects the hydraulic device to the storage device. The invention is therefore based on the object of providing a tensioning system, in particular a hydropneumatic tensioning system, of a roller mill in which the assembly effort and the space requirement and thus the installation costs are reduced and, in addition, the operation is optimized to reduce the operating and maintenance costs.

In the case of a clamping system of the type specified in the introduction, this object is achieved according to the invention in that the at least one grinding pressure and the at least one back pressure storage container can be exchanged together with the hydraulic unit and are designed as a modular hydraulic storage unit.

Advantageous refinements and useful developments of the invention are the subject of the dependent claims.

According to the invention, it is therefore provided that two separate, individually exchangeable assemblies or modules, a hydraulic unit and a separate storage unit are no longer assigned to a respective cylinder unit of the clamping system, but rather the at least one grinding pressure and the at least one back pressure storage container, in particular also all for the operation of the cylinder unit required pressure storage container to be included directly in the hydraulic unit or to be arranged within the hydraulic unit. A modular hydraulic accumulator unit designed in this way can then be connected as a self-contained assembly or module to the clamping system of a roller mill, removed therefrom or exchanged for another modular hydraulic accumulator unit, in particular of an identical design. The at least one grinding pressure and the at least one back pressure storage container are preferably arranged ready for operation within the modular hydraulic storage unit, so that they can be exchanged with the hydraulic unit, in particular only together. On additional pipelines which, in the arrangements known from the prior art, for connecting a hydraulic unit to a separate storage unit or for connecting a respective storage unit with a central hydraulic device are therefore not necessary.

Preferably, the modular hydraulic accumulator unit is pre-assembled, i.e. the at least one grinding pressure and the at least one back pressure storage container, in particular all pressure storage containers required for operating the cylinder unit, are arranged within the hydraulic storage unit and are connected and connected ready for operation. The hydraulic accumulator unit can then be delivered ready for installation to the construction site for installing the roller mill and the clamping system and only has to be connected there to the assigned cylinder unit. This enables a much easier installation, which in particular avoids assembly errors, shortens the installation time and thus reduces the installation costs overall.

In particular, the at least one grinding pressure and the at least one back pressure storage container, preferably all the respective pairs of grinding pressure and back pressure storage container, are then only or exclusively jointly designed as a component of and in the form of the self-contained and modular hydraulic storage unit. For this purpose, the respective grinding pressure and counterpressure storage containers are connected to one another ready for operation and arranged in an interconnected manner within the hydraulic storage unit. The storage containers are consequently connected to one another in a respective hydraulic storage unit ready for operation and connected, so that a self-contained hydraulic storage unit is formed which can only be replaced in its entirety. This ensures an identical structure and also a uniform, central regulation and / or control of all hydraulic accumulators, so that they can be interchanged with one another as desired. At the same time, assembly errors which can occur during the installation or replacement of individual pressure storage tanks or individual hydraulic devices, in particular also when they are connected, are thereby avoided. In particular, the grinding pressure storage container and the counterpressure storage container are arranged on a control block which has the necessary piping in the form of bores, and above this or the latter Holes connected and interconnected ready for operation. The control block is also part of the hydraulic accumulator unit or hydraulic unit and can be exchanged as a modular unit in unit with this and the grinding pressure container and the counter pressure container.

The invention therefore provides in an embodiment that the at least one grinding pressure and the at least one back pressure storage container can only be exchanged together with the hydraulic unit, in the form of a self-contained and modular hydraulic storage unit, the at least one grinding pressure and the at least one back pressure storage container, in particular as a module unit, preferably by means of a control block, ready for operation, in particular also with one another, connected and connected within the modular hydraulic accumulator unit.

The modular design and combination of the hydraulic storage unit with at least one grinding pressure and at least one counter-pressure storage container and possibly a control block to form a modular exchange unit results in the possibility of this modular unit "hydraulic storage unit" in the sense of a "plug-out / plug in" - Exchange, so that such a change can also be carried out by trained assistants and no specialists are required. This is even more the case if, in addition, the at least one grinding pressure and at least one back pressure storage container together with a control block also form a modular unit which is part of the modular hydraulic storage unit. This simplifies the assembly process for manufacturing the modular hydraulic accumulator unit.

In the tensioning system according to the invention, each cylinder unit is assigned a decentralized, modular hydraulic storage unit, which means that a central hydraulic device can be dispensed with on the one hand and the respective separate storage units are no longer required on the other. The decentralized and modular hydraulic accumulator unit according to the invention is designed to be considerably smaller than an otherwise customary centrally arranged hydraulic device and also requires a smaller installation space than previously known designs of decentralized hydraulic units with separately connected storage units.

According to an advantageous embodiment of the invention, it is provided that the modular hydraulic accumulator unit is arranged adjacent to the respectively assigned cylinder unit and is directly connected to it via hydraulic lines, in particular via a grinding pressure line and a back pressure hydraulic line.

By arranging the hydraulic storage unit adjacent, preferably directly adjacent, to the associated cylinder unit, the hydraulic lines between the respective cylinder unit and the associated hydraulic storage unit can be made particularly short, thereby reducing the losses that usually occur in an elongated line. The cylinder unit and the hydraulic accumulator unit are immediate, i. H. connected without any additional modules or modules. Preferably, to connect the hydraulic accumulator unit to the cylinder unit, in particular exclusively, a grinding pressure hydraulic line, by means of which hydraulic fluid between the at least one grinding pressure storage container and the hydraulic cylinder, and a counter-pressure hydraulic line, by means of which hydraulic fluid is guided between the at least one counter-pressure storage container and the hydraulic cylinder, are provided.

An expedient embodiment of the invention provides that the modular hydraulic storage unit has a leakage oil container and is connected to the cylinder unit, in particular directly, via a leakage oil hydraulic line.

In addition, a leakage oil reservoir can also be integrated or accommodated in the hydraulic storage unit and connected to the cylinder unit by means of a further hydraulic line, a leakage oil hydraulic line, preferably also directly. In combination with the embodiment described above, all hydraulic lines leaving the cylinder unit thus lead into the hydraulic accumulator unit or is the cylinder unit directly connected to the hydraulic storage unit by means of the hydraulic lines, so that only three hydraulic lines (grinding pressure, counterpressure and leakage oil hydraulic lines) lead to the respectively assigned cylinder unit per hydraulic unit. In an advantageous embodiment, the hydraulic lines are implemented as hydraulic hoses, which can be connected to the cylinder unit and / or the hydraulic accumulator unit in a simple manner, each with a quick-release fastener. Consequently, it is possible to design the hydraulic accumulator unit with only three external line connections. Since only hydraulic hoses are used between the hydraulic storage unit and the respectively assigned cylinder unit, all steel pipelines are eliminated and the material costs, the assembly costs and the assembly times are considerably reduced. The costs for pickling and flushing the steel lines are eliminated, as are the costs for pressure tests.

The possibility of simply connecting or disconnecting the hydraulic storage unit to the cylinder unit using quick-release fasteners

Overall availability of the clamping system increased. In a corresponding manner, power supply and signal cables can be connected or detached from the hydraulic unit by means of simple plug connections, as a result of which the assembly effort and the assembly costs are further reduced. In this way, installation and replacement of a modular hydraulic accumulator unit are also conceivable without specially trained specialist personnel, in particular without the use of an electrician.

Furthermore, it is advantageously provided that the modular

Hydraulic storage unit has an integrated oil tank.

By also integrating the usually provided oil tank into the hydraulic storage unit or pre-assembling it ready for operation, all components (pressure storage tank, leakage oil tank, oil tank) provided for holding hydraulic fluid, in particular pressure oil or hydraulic oil, can be integrated in the hydraulic storage unit or have the hydraulic storage unit all for the absorption of hydraulic fluid, in particular of pressure oil or Hydraulic oil, components provided. These components are expediently arranged within an oil drip pan, which is also formed as part of the hydraulic accumulator unit. Because of this much more compact design, in which the at least one grinding pressure storage container, the at least one back pressure storage container and preferably the leakage oil container as well as an oil tank and an oil drip pan are integrated in the hydraulic storage unit, significantly less hydraulic fluid is also required, which further reduces operating costs. At the same time, the risk of leakage decreases. All in all, apart from the three hydraulic lines described above, no additional lines for guiding hydraulic fluid between the hydraulic storage unit and external components, such as an oil tank, are necessary. Other line connections, such as a return line, a suction line and / or a control pressure line, are also designed internally in the module.

In a further advantageous embodiment of the invention, the modular hydraulic storage unit each has a pump device for the at least one grinding pressure and the at least one back pressure storage tank, the respective pump device being designed to regulate the pressure to be set in the grinding pressure storage tank or in the back pressure storage tank.

In a further development of this embodiment, it can be expedient for each pump device to be assigned a frequency-controlled motor, in particular a grinding pressure motor or a counter-pressure motor, and integrated in the hydraulic storage unit, the pressure to be set in the grinding pressure and / or in the counter-pressure storage container being based on the frequency of the respective associated motor is controllable.

In an advantageous further development it is therefore provided that each pressure storage container is assigned its own pump device with its own associated frequency-controlled motor. The pump devices with the respective frequency-controlled motors are also integrated in the hydraulic accumulator device and are preferably ready for operation with them connected so that the pressure to be set in the respective pressure storage container can be regulated via the frequency of the correspondingly assigned motor. Instead of the standard motor used up to now, which is provided both for regulating the pressure inside the grinding pressure storage container and within the counter-pressure storage container, two frequency-controlled motors are used in accordance with the design of the invention, as a result of which the proportional valves usually used for pressure control are also eliminated. In addition, it is possible to operate the frequency-controlled motors only when the grinding pressure or back pressure actually has to be readjusted, ie it drops by, for example, 2 bar compared to a preset pressure. The use of separate, frequency-controlled motors for each pressure storage container, ie for the at least one grinding pressure and the at least one back pressure storage container, consequently means that the hydraulic storage units require a significantly lower drive power than is the case with conventional hydraulic units. In addition, because of the line lengths standardized in this way between the respective cylinder unit and the associated hydraulic storage unit, the cylinder units can be controlled in a more targeted manner, as a result of which a much more uniform grinding force can be applied to the grinding tools of the roller mill. For this purpose, it is provided that the length of the hydraulic lines between the modular hydraulic accumulator units and the respectively assigned cylinder units of a roller mill and a power plant block is essentially the same.

Overall, the hydraulic accumulator unit therefore requires a significantly lower total output and, owing to the considerably shorter operating times of the two frequency-controlled motors in part-load operation, has a significantly lower power requirement, which in turn enables savings in energy costs. In addition, the hydraulic fluid is heated less, which means that a complex cooling system, in particular water cooling, can be dispensed with and the operating costs are further reduced.

Instead of the commonly used, complex water cooling, however, it is optionally also possible, according to an expedient embodiment of the invention, for the modular hydraulic accumulator unit to include integrated air cooling. A further advantage of the invention consists in an embodiment according to which each modular hydraulic accumulator unit is connected to a central control unit and can be controlled by means of this central control unit.

A central control unit, which is connected to each of the modular hydraulic storage units and is provided for controlling all modular hydraulic storage units, enables an improved and optimized operation of the roller mill to be implemented. The central control unit expediently receives the measurement signals transmitted by the respective modular hydraulic storage units, controls and adjusts the individual modular hydraulic storage units to one another. The central control unit can be equipped with a screen, via which the respective measured values and, if applicable, error messages or warnings for all or individual modular hydraulic accumulator units can be clearly displayed. This considerably simplifies checking and troubleshooting by appropriate operating personnel.

Finally, for a quick and uncomplicated exchange of defective hydraulic units according to an embodiment of the invention, it is also advantageous that two modular hydraulic accumulator units can be connected in parallel to a cylinder unit of the clamping system.

In the context of the inventive idea, it is therefore provided that the modular hydraulic accumulator units can be easily replaced in the event of a defect or in the course of maintenance work. Due to the modular design, it is therefore possible to connect two hydraulic accumulator units to a cylinder unit at the same time and in parallel. Controllable shut-off valves can then immediately be used to convert from one modular hydraulic storage unit to the other modular hydraulic storage unit. For example, when a malfunction is detected on a first modular hydraulic accumulator unit that is currently in operation, it is possible to switch over to a second modular hydraulic accumulator unit, which initially works in parallel is connected and then takes over the operation by switching the shut-off valves.

The initially mentioned inventive task is consequently also achieved by a modular hydraulic storage unit for a clamping system of a roller mill, in particular a hydropneumatic clamping system, preferably according to one of the previously described embodiments, the modular hydraulic storage unit being a ready-to-fit, preferably self-contained module with a hydraulic unit and formed at least one grinding pressure and at least one back pressure storage container and can be connected via hydraulic lines, in particular directly, to a cylinder unit of the clamping system.

Here, too, advantageous refinements and expedient developments of the invention are the subject of the dependent claims.

The modular hydraulic accumulator unit in one embodiment of the invention is characterized in that the at least one grinding pressure container and the at least one counterpressure accumulator container, in particular as a module unit, preferably by means of a control block, are connected ready for operation, in particular also with one another, and are arranged within the modular hydraulic storage unit.

The same advantages result as those listed above with regard to the clamping system.

Designing the hydraulic accumulator unit as a ready-to-install module with at least one preassembled or integrated grinding pressure accumulator and at least one preassembled or integrated counterpressure accumulator makes it possible for any modular hydraulic accumulator unit to be replaced as required within a roller mill or even within a power plant block. The modular design enables particularly simple and quick assembly and disassembly of the individual hydraulic accumulator units. Regardless of which component of the modular Hydraulic storage unit (e.g. pressure storage tank, pump, motor, etc.) is actually responsible for a defect, a defective hydraulic storage unit can be easily replaced with a new hydraulic storage unit, so that the downtimes necessary in this case can be kept very short.

A modular hydraulic storage unit is preferably connected exclusively by means of three hydraulic lines, a grinding pressure hydraulic line, a back pressure hydraulic line and a leakage oil hydraulic line, as well as a connection to the power supply and a line for transmitting signals to the clamping system of a roller mill. For particularly convenient and quick assembly and disassembly, the corresponding connections are designed as plug connections for the power and signal line and as quick-release fasteners for the hydraulic lines, which are preferably listed as hydraulic hoses. Special technical knowledge, in particular in the electrical engineering field for connecting the electrical connections, is therefore not necessary for the assembly or disassembly of a modular hydraulic accumulator unit.

The clamping system according to the invention and the modular hydraulic accumulator unit according to the invention are suitable both for the installation of new roller mills, but also for converting or retrofitting old systems without changing the control system.

Finally, a roller mill, comprising a tensioning system, in particular a hydropneumatic tensioning system, with a modular hydraulic accumulator device, as previously trained and developed, is provided to solve the object of the invention.

The invention is explained in more detail below using the drawings as an example. These show in

FIG. 1 shows a schematic illustration of a conventional roller mill with a central hydraulic device, FIG. 2 shows a schematic illustration of a conventional clamping system of a roller mill as shown in FIG. 1, with a central hydraulic device,

Figure 3 shows an exemplary embodiment of an inventive

Roller mill with modular flydraulic storage units,

Figure 4 is a schematic representation of the invention

Clamping system of the embodiment shown in Figure 3, with modular hydraulic storage units and

Figure 5 shows an exemplary embodiment of a modular hydraulic storage unit according to the invention.

1 shows a schematic representation of a conventional roller mill 10, as known from the prior art, here designed as a roller bowl mill, with a central hydraulic device 30. In the roller mill 10, 12 grinding tools 14 in the form of grinding rollers are attached to a clamping frame can be ground or ground a rotating grinding table 16 arranged by rotating the grinding plate 16 and the grinding tools 14. A clamping system 18 is arranged on the clamping frame 12, by means of which the grinding tools 14 are pressed onto the rotating grinding plate 16. The grinding plate 16 is arranged on a grinding bowl carrier 20, which is seated on a gear 21, which in turn is arranged on a mill base 22.

By means of the clamping system 18 arranged on the clamping frame 12, a desired contact pressure or grinding pressure of the grinding tools 14 and thus a grinding force can be applied to the grinding plate 16 or to the grinding material located on the grinding plate 16, whereby, for example, the degree of comminution or Throughput of the ground material to be ground can be adjusted.

A clamping system 18 usually has a plurality of cylinder units 24, the number of which is usually determined as a function of the grinding tools 14, with one cylinder unit 24 being usually provided per grinding tool 14. The cylinder units 24 are according to the embodiment shown in FIG. 1 circular, equidistant from each other, arranged around the roller mill 10 on the clamping frame 12. An associated storage unit 26 is also assigned to each cylinder unit 24. The cylinder units 24 shown here are designed as double-acting hydraulic cylinders, so that counter to the downward pressure in the direction of the grinding plate 16, an upward counterforce can also be exerted, by means of which, for example, the grinding tools 14 are lifted from the grinding plate 16 is feasible. To set the grinding force or the counterforce, the working pressure within respective hydraulic chambers of the hydraulic cylinder assigned to the annular surface or the piston surface is increased or decreased by hydraulic fluid being pumped into the corresponding hydraulic chamber or escaping from the corresponding hydraulic chamber. For this purpose, the hydraulic chambers are connected via a grinding pressure hydraulic line 25c to a grinding pressure storage tank 26c or a back pressure hydraulic line 25b to a back pressure storage tank 26b. The grinding pressure storage container 26c and the back pressure storage container 26b are designed as bladder accumulators and are combined in the storage unit 26. To supply the storage units 26 with hydraulic fluid, in particular pressure oil or hydraulic oil, the central hydraulic unit 30 is usually arranged next to the roller mill 10 on the mill foundation and is connected to the individual storage units 26 and the associated cylinder units 24 by means of ring lines, not shown here, designed as pipelines.

The usual ring lines or connecting lines 28 can be found in the schematic illustration of a conventional clamping system 18 shown in FIG. 2 of a roller mill 10 as shown in FIG. 1 with a central hydraulic device 30. The cylinder units 24 and the storage units 26 are connected via the connecting lines 28, preferably via pipelines, to the single, centrally arranged hydraulic device 30, via which hydraulic fluid is conducted to the cylinder units 24 and the storage units 26. The connecting lines 28 are arranged in a ring around the roller mill 10 and have spur lines which branch off from the ring-shaped connecting lines 28 and to the Guide cylinder units 24 and / or the storage units 26. The connecting lines 28 in this case comprise a control pressure suction line 28a connected to the storage unit 26, a counter pressure line 28b and a grinding pressure line 28c, which each lead to the storage unit 26 and to the cylinder unit 24, a leakage oil line 28d connected to the cylinder unit 24, one to the storage unit 26 connected return storage protection line 28e and a suction line 28f also connected to the storage unit 26.

A schematic representation of an exemplary embodiment of a roller mill 110 according to the invention can be seen in FIG. 3. The operation of the roller mill 110 according to the invention corresponds to the operation of the known roller mill 10, as shown in Figure 1. In the roller mill 110 according to the invention, grinding tools 114 in the form of grinding rollers are also attached to a clamping frame 112, which grinding material can be ground or ground on a rotating grinding plate 116 by rotating the grinding plate 116 and the grinding tools 114. The grinding tools 114 are pressed onto the rotating grinding table 116 or lifted by the clamping frame 112 and the clamping system 118 arranged on the clamping frame 112 via the cylinder units 124 designed as double-acting hydraulic cylinders. The grinding plate 116 is arranged on a grinding bowl carrier 120, which is seated on a gear 121, which in turn is arranged on a mill base 122.

Instead of a central hydraulic device 30 (see FIG. 1), a decentralized, modular hydraulic storage unit 130 is assigned to each cylinder unit 124 in the exemplary embodiment of the clamping system 118 according to the invention. The number of cylinder units 124 and thus the hydraulic accumulator units 130 usually corresponds to the number of grinding tools 114, whereby usually one cylinder unit 124 with an associated hydraulic accumulator unit 130 is provided per grinding tool 114. In the embodiment shown in FIG. 3, the cylinder units 124 are each arranged at the same distance from one another on the clamping frame 112. The modular Hydraulic accumulator units 130 are preferably located directly next to the respective cylinder unit 124 on the mill foundation.

Each modular hydraulic storage unit 130 has both a grinding pressure storage container 126c and a counter-pressure storage container 126b, so that a separately connected storage unit 26 (see FIG. 1) is no longer required, as a result of which the modular hydraulic storage units 130 are each directly connected to the associated cylinder unit 124. Consequently, each cylinder unit 124 of the clamping system 118 is assigned only the hydraulic storage unit 130, which is designed as a self-contained assembly or a module, and is directly connected to the respectively assigned cylinder unit 124 exclusively via hydraulic hoses 128 (not shown here). Both when installing and commissioning the roller mill 110 and the associated clamping system 118, and when replacing defective components, the hydraulic accumulator unit 130 is connected as a self-contained assembly or module together, in particular only jointly, with the grinding pressure accumulator 126c and the counterpressure accumulator 126b, removed and exchanged.

FIG. 4 schematically shows a clamping system 118 according to an exemplary embodiment of the invention, as shown in FIG. 3, in which a modular hydraulic accumulator unit 130 is assigned to each cylinder unit 124. The cylinder units 124 with the associated modular hydraulic accumulator units 130 are arranged in a circle around the roller mill 110 at the same distance from one another. Each of the modular hydraulic storage units 130 comprises a grinding pressure storage container 126c and a back pressure storage container 126b, and is directly connected to corresponding hydraulic chambers of the cylinder unit 124 designed as a hydraulic cylinder via hydraulic lines or hydraulic hoses 128, more precisely via a grinding pressure hydraulic line 125c and a back pressure hydraulic line 125b. An additional leakage oil hydraulic line 125d runs between a cylinder unit 124 and the respectively assigned modular hydraulic accumulator unit 130, so that a cylinder unit 124 is connected to the associated hydraulic accumulator unit 130 exclusively via three hydraulic lines is. The hydraulic lines are preferably designed as hydraulic hoses 128 and are connected to the cylinder unit 124 via a quick connector.

The hydraulic accumulator units 130, which are arranged decentrally and have a modular design according to the invention, have a considerably more compact design than a centrally provided hydraulic device 30 (see FIG. 1) and a significantly smaller space requirement than a hydraulic unit with a separately connected accumulator unit 26 (not shown). According to the invention, both the annular connecting lines 28 and external connecting lines running between a storage unit 26 and a hydraulic unit, mostly in the form of pipelines, are no longer required. The previously installed connecting lines 28 for the control pressure suction line 28a, the return storage protection line 28e and the suction line 28f are provided here within the hydraulic accumulator unit 130, whereby further costs, in particular for flushing and pickling the pipelines or also for carrying out a pressure test, can be saved .

FIG. 5 shows an exemplary embodiment of a modular hydraulic accumulator unit 130 according to the invention. The hydraulic accumulator unit 130 comprises a grinding pressure accumulator 126c, which is designed here as a bladder accumulator, and a counterpressure accumulator 126b. Both pressure accumulator containers 126c, 126b are arranged, connected and connected within the hydraulic accumulator unit 130 ready for operation, so that the pressure accumulator containers 126c, 126b can each be connected to an assigned cylinder unit 124 (not shown here) via a hydraulic line or a hydraulic hose 128. The hydraulic storage unit 130 also has a leakage oil tank 134, which is also connected and connected ready for operation, so that the leakage oil tank 134 can also be connected to the associated cylinder unit 124 (not shown here) via a leakage oil hydraulic line 125d. The pressure storage tanks 126c, 126b are mounted on a control block 136 above an oil tank 135 for holding hydraulic fluid, in particular pressure oil or hydraulic oil Oil drip pan 137 arranged. The control block 136 is designed in the manner of a hydraulic console and contains the necessary line connections between the pressure storage tanks 126b, 126c and to connecting lines to the hydraulic fluid tank 135 and possibly further components or components of the roller mill 110 in the form of internal bores with corresponding outlets on the control block side surfaces. These make it possible to combine the block of grinding pressure storage container 126c, counter-pressure storage container 126b and control block 136 into a modular unit that can be handled as one component. The control block 136, the oil tank 135 and the oil drip pan 137 are integrated into the hydraulic storage unit 130 as part of the latter. A grinding pressure motor 131c and a back pressure motor 131b are assigned to the grinding pressure storage container 126c and the back pressure storage container 126b, each of which is designed as a frequency-controlled motor. The pressure to be set within the pressure storage containers 126c, 126b can thus be regulated via a respective pump device based on the frequency of the motor 131c, 131b. By replacing the previously standard single motor for regulating the pressure of both pressure storage tanks 126c, 126b by two respective frequency-controlled motors 131c, 131b, the hydraulic storage units 130 require a significantly lower drive power overall. In addition to the two motors 131 c, 131 b, measuring devices, control valves, pressure relief valves and oil filters are also arranged on or above the oil tank 135. In the uppermost area, the hydraulic accumulator unit 130 shown here also has air cooling 133, which can be optionally and, if necessary, also integrated. Overall, the hydraulic accumulator unit 130 therefore only requires one external connection each for connection to the required power supply and for connection to a control unit, as well as three external hydraulic connections to which the grinding pressure hydraulic line 125c, counter-pressure hydraulic line 125b and leakage oil hydraulic line 125d can be connected.

To control and regulate each hydraulic accumulator unit 130 is connected to a central control unit in a data and signal-transmitting connection. The central control unit is used to receive and process signals the control system of the boiler as well as measured values and measurement signals from the individual hydraulic storage units 130.

The central control unit records, for example:

Grinding pressure, current values, per hydraulic accumulator unit 130,

Grinding pressure, current value, averaged over all hydraulic accumulator units 130,

Back pressure, current values, per hydraulic accumulator unit 130,

Back pressure, current value, averaged over all hydraulic accumulator units 130,

Oil level, OK / not OK, per hydraulic accumulator unit 130,

Oil temperature, OK / not OK, per hydraulic accumulator unit 130,

Oil inside the oil pan 137, OK / not OK, each

Hydraulic accumulator 130,

Oil filter, OK / not OK, per hydraulic accumulator unit 130.

For example, for the following error messages, a warning in

Control system generates:

Oil level = minimum,

Oil temperature> 70 ° C,

Oil filter = 100% full,

There is oil in the oil pan 137.

On the basis of the warning generated, it is possible for the operating personnel to replace the modular hydraulic storage unit 130 which issues the error message with a new modular hydraulic storage unit 130 and only then to look for the specific cause of the error message. This significantly reduces downtime in the event of a warning or even a shutdown due to an error message.

The following error messages in particular result in the hydropneumatic clamping system 118 being switched off:

Oil level <minimum,

Oil temperature> 80 ° C, Electrical error.

By regulating and controlling all the modular hydraulic accumulator units 130 by means of a single central control unit, the individual hydraulic accumulator units can be coordinated with one another and thus an improvement in operation can be achieved.

In particular, the at least one grinding pressure reservoir 126c and the at least one back pressure storage reservoir 126b, preferably all respective pairs of grinding pressure and back pressure storage reservoirs 126c, 126b, are each designed to be interchangeable only or exclusively together, in the form of a self-contained and modular hydraulic storage unit 130. For this purpose, the respective grinding pressure and counterpressure storage containers 126c, 126b are connected to one another in a ready-to-operate state and are connected in a circuit within the hydraulic storage unit 130. The storage tanks 126c, 126b are consequently connected and connected to one another within the respective hydraulic storage unit 130 ready for operation, so that a self-contained hydraulic storage unit 130 is formed which can only be replaced in its entirety. This ensures an identical structure and also a uniform, central regulation and / or control of all hydraulic accumulator units 130, so that they can be interchanged with one another as desired. At the same time, assembly errors which can occur when installing or replacing individual pressure storage tanks 126b, 126c or individual hydraulic devices, in particular also when they are connected, are thereby avoided. In particular, the grinding pressure storage container 126c and the counterpressure storage container 126b are arranged on the control block 136 having the necessary piping in the form of bores, and are connected and connected to one another ready for operation via this or its bores. The control block 136 is also part of the hydraulic accumulator unit 130 or hydraulic unit and can be exchanged in unit with this and the grinding pressure container 126c and the counterpressure container 126b as a modular unit. Reference symbol list:

10, 110 roller mill

12, 112 stenter

14, 114 grinding tool

16, 116 grinding plates

18, 118 clamping system

20, 120 grinding bowl holders

21, 121 gearbox

22, 122 mill base

24, 124 cylinder unit

25b, 125b back pressure hydraulic line

25c, 125c grinding pressure hydraulic line

125d hydraulic oil drain line

26 storage unit

26b, 126b back pressure storage tank

26c, 126c grinding pressure storage container

28a control pressure suction line 28b back pressure line

28c grinding pressure line

28d drain line

28e return storage protection line 28f suction line

128 hydraulic hoses

30 central hydraulic device

130 modular hydraulic accumulator unit 131 b counter-pressure motor

131 c grinding pressure motor

133 air cooling

134 leakage oil container

135 oil tank

136 control block

137 oil drip pan

Claims

1. clamping system (118), in particular hydropneumatic clamping system, a roller mill (110) with at least two, each for applying one

Grinding and a counterpressure formed cylinder units (124), each cylinder unit (124) at least two pressure storage containers (126c, 126b), a grinding pressure (126c) and a back pressure storage container (126b), as well as one arranged close to the respective cylinder unit (124) Hydraulic unit is assigned, characterized in that

that the at least one grinding pressure (126c) and the at least one back pressure storage container (126b) can be exchanged together with the hydraulic unit as a modular hydraulic storage unit (130).

2. Clamping system (118) according to claim 1, characterized in that the at least one grinding pressure (126c) and the at least one

Back pressure storage container (126b) can only be exchanged together with the hydraulic unit, in the form of a self-contained and modular hydraulic storage unit (130), the at least one grinding pressure unit (126c) and the at least one

Back pressure storage container (126b), in particular as a module unit, preferably by means of a control block (136), ready for operation, in particular also with one another, connected and connected within the modular hydraulic storage unit (130).

3. Clamping system (118) according to claim 1 or 2, characterized in that the modular hydraulic accumulator unit (130) is arranged adjacent to the respectively assigned cylinder unit (124) and with it via hydraulic lines (128), in particular via a grinding pressure (125c) and a back pressure hydraulic line (125b) is directly connected.

4. Clamping system (118) according to one of claims 1 to 3, characterized in that the modular hydraulic storage unit (130) one Has leakage oil tank (134) and is connected to the cylinder unit (124), in particular directly, via a leakage oil hydraulic line (125d).

5. Clamping system (118) according to one of the preceding claims, characterized in that the modular hydraulic storage unit (130) has an integrated oil tank (135).

6. Clamping system (118) according to one of the preceding claims, characterized in that the modular hydraulic storage unit (130) each has a pump device for the at least one grinding pressure (126c) and the at least one back pressure storage container (126b), the respective pump device for regulation of the pressure to be set in the grinding pressure (126c) or in the back pressure storage container (126b).

7. clamping system (118) according to claim 6, characterized in that each

Pump device is assigned a frequency-controlled motor (131c, 131b), in particular a grinding pressure motor (131c) or a counterpressure motor (131b) and integrated in the hydraulic accumulator unit (130), the in the grinding pressure (126c) and / or in the

Back pressure storage container (126b) pressure to be set via the frequency of the respectively assigned motor (131 c, 131 b) can be regulated.

8. clamping system (118) according to any one of the preceding claims, characterized in that the modular hydraulic storage unit (130) comprises an integrated air cooling (133).

Clamping system according to one of the preceding claims, characterized in that each modular hydraulic accumulator unit (130) is connected to a central control unit and can be controlled by means of this central control unit.

10. Clamping system according to one of the preceding claims, characterized in that two modular hydraulic accumulator units (130) can be connected in parallel to a cylinder unit (124) of the clamping system (118).

11. Modular hydraulic accumulator unit (130) for a clamping system (118) of a roller mill (110), in particular hydropneumatic clamping system, in particular according to one of the preceding claims, characterized in that

that the modular hydraulic accumulator unit (130) as a ready-to-install, preferably self-contained module with a hydraulic unit and at least one grinding pressure (126c) and at least one

Back pressure storage container (126b) is formed and can be connected via hydraulic lines (128), in particular directly, to a cylinder unit (124) of the clamping system (118).

12. Modular hydraulic accumulator unit (130) according to claim 11, characterized in that the at least one grinding pressure (126c) and the at least one counterpressure accumulator container (126b), in particular as a module unit, preferably by means of a control block (136), ready for operation, in particular also with one another, connected and connected within the modular hydraulic accumulator unit (130).

13. Rolling mill (110), comprising a clamping system (118), in particular a hydropneumatic clamping system, with a modular hydraulic accumulator device (130) according to one of claims 1-12.