DE102011121271A1 - Hydrostatic circuit, has control unit regulating storage pressure to instantaneous pressure set point of secondary device or high instantaneous pressure set point of secondary units, and working line connected to storage unit - Google Patents

Abstract

The circuit (1) has a working line (14) i.e. high pressure line, connected to a storage unit (8) that is connected to an adjustable primary unit (2) i.e. pure pump, or multiple adjustable secondary units (4, 6) i.e. adjustable hydrostatic axial piston machines, where storage pressure is embossed in the hydrostatic circuit. A control unit (10) regulates storage pressure to an instantaneous pressure set point of the secondary device or high instantaneous pressure set point of the secondary units. The primary unit comprises a steep unit for adjusting a hydrostatic machine.

Description

The invention relates to a hydrostatic circuit according to the preamble of patent claim 1.

According to the principle of a secondary control for hydrostatic circuits, hydraulic consumers of this circuit (hereinafter referred to as secondary units) are operated on a constant pressure network. In the secondary control is a speed control loop with a geometric displacement or a pivot angle or eccentricity of the secondary unit as a free size. A torque of the secondary unit is proportional to a set geometric stroke volume. Secondarily controlled units "seek" while specifying a speed automatically the torque required to hold at a given operating pressure, which is impressed on a hydrostatic accumulator of the circuit (accumulator pressure), a predetermined speed can.

Such a secondary-controlled hydrostatic circuit has a primary unit, for example an adjustable pump unit and the secondary side one or more secondary units, which are connected in a parallel circuit to a working line of the primary unit or to the high pressure line. The secondary units can work both motorized and regenerative. A major advantage of the secondary control is that in the energy-carrying working lines of the circle for a distribution of the pressure medium to the individual secondary units no throttle bodies must be arranged.

A central component of the hydrostatic circuit is the hydrostatic accumulator, which impresses the accumulator pressure on the hydrostatic circuit. In this case, the pressure is virtually constant, that is, the pressure level is variable, but a state of charge of the memory determines the working pressure prevailing in the hydrostatic circuit.

The patent DE 43 08 198 C1 shows a operated according to the principle of secondary control hydrostatic circuit with a control of the torque as a function of a pivot angle or an eccentricity of a secondary unit. The control concept envisages regulating the displacement of the secondary unit taking into account the operating parameters pressure, speed and temperature.

A disadvantage of this solution is that it is not ensured for a memory of the hydrostatic circuit that the degree of filling allows a recording of currently accumulating braking energy of a secondary unit in full. Thus, valuable kinetic energy of the loads driven by the secondary units can no longer be recovered for recuperation, which adversely affects hydrostatic cycle efficiency.

In contrast, the invention has for its object to provide a hydrostatic circuit with improved efficiency.

This object is achieved by a hydrostatic circuit having the features of patent claim 1.

Advantageous developments of the invention are described in the claims 2 to 8.

A hydrostatic circuit, in particular an open or a closed circuit, has a working line, in particular a high-pressure line, to which an adjustable primary unit for supplying pressure medium to one or more adjustable secondary units is connected. Furthermore, the hydrostatic circuit has the one or more adjustable, in particular secondary-controlled, secondary units. These are also connected to the working line, in particular in a parallel circuit. These secondary units serve in particular an acceleration or deceleration of a load or a consumer and can work by motor or generator. During normal operation of the hydrostatic circuit, a hydrostatic accumulator which can be charged in particular with braking energy of the one or more secondary units or with pressure energy of the primary unit is connected to the working line. A memory pressure is impressed on the hydrostatic circuit via this reservoir. The pressure in the working line is therefore the memory pressure prevailing in the memory or depends on it. The memory pressure in turn depends on the degree of filling of the memory. According to the invention, the hydrostatic circuit has a control unit, in particular a control / regulation unit, via which the accumulator pressure can be regulated to an instantaneous pressure setpoint of the one secondary unit or to a highest instantaneous pressure setpoint of the plurality of secondary units.

Since a torque of a secondary unit of the hydrostatic circuit is approximately proportional to the accumulator pressure, it is ensured via the control unit designed in such a way that always enough pressure energy is available for generating the required torque for each secondary unit. In addition, it prevents in this way that a higher storage pressure than required is stored in the memory. Thus, the degree of filling of the memory is too each moment optimally adapted to the torque requirements of the one or more secondary units of the circle and it is available for a braking operation of the one or more secondary units in the memory enough free volume. In this way, it is also possible to decouple the primary unit from the one or more secondary units. This means that the circuit can be removed by the one or more secondary machines at a first time pressure medium and at a second time via the primary unit required pressure medium can be supplied.

In an advantageous development of the instantaneous pressure setpoint is stored in the control unit as a function of a target speed or a current speed of the respective secondary unit.

In a particularly preferred advantageous embodiment, the control unit is connected via a respective signal connection, in particular via a signal line, with a speed determination unit of the one or more secondary units. In addition, the control unit is connected to a pressure determination unit arranged on the memory, via which the accumulator pressure or a pressure dependent thereon can be determined. Furthermore, the control unit is connected to an actuating unit of the primary unit. In the control unit thus takes place a signal processing of an incoming speed signal. The function stored in the control unit for each of the secondary units (instantaneous pressure setpoint as a function of the instantaneous speed) is used to determine the instantaneous pressure setpoint value for each secondary unit. In the case of several secondary units or instantaneous pressure setpoints, the highest of the instantaneous pressure setpoints is also determined. The instantaneous pressure setpoint of a secondary unit or the highest of the instantaneous pressure setpoint values is then the one to which the accumulator pressure is to be regulated by the control unit. The accumulator pressure can be increased, in which the control unit transmits a signal for increasing a pressure medium volume flow via the signal line, with which it is connected to the steep unit of the primary unit. Depending on the design of the primary unit, the signal can cause, for example, a swivel angle or an enlargement of the eccentricity or an enlargement of an opening cross section of a pressure medium flow path of the primary unit. As a consequence, the primary unit is controlled so that additional pressure medium is conveyed into the working line of the circuit. In otherwise stationary consumption conditions of the secondary units, this results in a filling of the hydrostatic accumulator and the accumulator pressure increases.

In a further preferred development, the primary unit has a hydrostatic machine which can be adjusted via the setting unit. This can be designed as a pure pump. Alternatively, it is designed both for pump operation and for engine operation, so that it can be transmitted in engine operation via a mechanical coupling to an internal combustion engine, a torque.

In another preferred development, the primary unit has a hydrostatic pump and a valve which can be adjusted via the setting unit of the primary unit, and via which a pressure medium volume flow conveyed into the working line can be changed. The valve is arranged in a preferred embodiment in a valve block. In this valve block further pressure fluid flow paths may be formed, via which further - non-secondary regulated - consumers of the primary unit can be supplied with pressure medium. The secondary-regulated circuit is then decoupled from the non-secondary-regulated consumers via the adjustable valve. In this case, existing hydraulic structures can be taken over by the working machines.

In a preferred embodiment, the control unit is designed to be particularly compact when it is connected via a respective signal connection, in particular a signal line, with an actuating unit of the one or more secondary units. Thus, via the control unit and the secondary control of the secondary units, for example, the control of a swivel angle or eccentricity occur.

Preferably, the one hydrostatic secondary unit or at least one of the hydrostatic secondary units of an axial piston machine or a radial piston machine. Alternatively or additionally, the one or more hydrostatic secondary units can also have more than one, for example two or three, axial piston or radial piston machines. A secondary unit with several machines advantageously has a higher dynamics.

In a further advantageous embodiment of the invention, the hydrostatic circuit in addition to the one memory at least one further memory, which is connected to the working line.

In the following, three embodiments of a hydrostatic circuit according to the invention will be explained in more detail with reference to drawings.

Show it

1 a first embodiment of a hydrostatic circuit,

2 a torque setpoint characteristic of a secondary unit of the first embodiment as a function of a rotational speed of the secondary unit, as well as a pressure setpoint characteristic of the secondary unit proportional to the torque setpoint characteristic as a function of the rotational speed,

3 a torque characteristic of the secondary unit of the first embodiment according to 2 as a function of the rotational speed of the secondary unit, as it results under the exclusive use of a hydrostatic accumulator as a pressure medium source or pressure medium sink, and a torque-curve proportional to the accumulator pressure characteristic as a function of the rotational speed,

4 one of the pressure setpoint characteristic and the accumulator pressure characteristic in accordance with 2 and 3 resulting pressure setpoint characteristic of the secondary unit of the first embodiment,

5 A second embodiment of a hydrostatic circuit and

6 a third embodiment of a hydrostatic circuit.

According to 1 has a hydrostatic circuit according to the invention 1 a primary unit 2 for pressure medium supply, two secondary units 4 and 6 for driving or braking a consumer 24 . 26 , a hydrostatic accumulator 8th and a control unit 10 , To a high pressure connection 12 the primary unit 2 is a work management 14 connected. Via a first work line branch 14a is the secondary unit 4 , via a second work line branch 14b the secondary unit 6 and via a third work line branch 14c the hydrostatic accumulator 8th with the work management 14 connected. The hydrostatic circuit 1 is open, with the primary unit 2 and the two secondary units 4 and 6 with a tank T in fluid communication stand. Via a work line branch 16 is to the energy or high pressure working line 14 a spring-loaded in the closed position pressure relief valve 18 connected, which relieved the tank T out.

Both hydrostatic secondary units 4 . 6 are each about a wave 20 . 22 with the consumer assigned to them 24 . 26 , For example, a slewing of a crane or a driven wheel of a traction drive or a winch coupled. About the waves 20 . 22 is thus, provided the hydrostatic secondary units 4 . 6 working in motor mode, a torque from the secondary units 4 . 6 to the consumers 24 . 26 transferable.

To detect a respective speed of the hydrostatic secondary units 4 . 6 indicates the hydrostatic circuit 1 for each secondary unit 4 . 6 a speed determination unit 28 . 30 on that the speed on the shaft 20 . 22 determine. The secondary units 4 . 6 are designed as adjustable hydrostatic axial piston machines and accordingly each have an actuating unit 32 . 34 for adjusting a stroke volume or swivel angle. Both secondary units 4 . 6 can be pivoted beyond their zero angle. For detecting a storage pressure or a dependent on the accumulator pressure in the working line 14 prevailing operating pressure is a pressure determination unit 36 at the third line of work 14c of the memory 8th arranged. Also the primary unit 2 is designed adjustable and has an actuating unit 38 on.

The following is a designated stationary operation of the hydrostatic circuit 1 described. In this operation promotes the primary unit 2 a constant pressure medium volume flow in the working line 14 , At the pressure relief valve 18 is a not to be exceeded maximum pressure of the circuit preset and protects against pressure overload. The one from the primary unit 2 supplied pressure medium volume flow is divided into the two secondary units 4 and 6 on. In a time-previous operating interval, the pressure medium volume flow was used to fill the hydrostatic accumulator 8th with pressure medium up to a later detailed explained pressure setpoint of the accumulator pressure. The accumulator pressure is the hydrostatic circuit 1 from the store 8th imprinted so that in the work line 14 or in the work line branches 14a to 14c and 16 and at the high pressure ports of the secondary units of the accumulator pressure is applied.

In steady-state operation of the circuit 1 is that of the primary unit 2 supplied pressure medium volume flow and that of the secondary units 4 . 6 taken off volume flow same size. The accumulator pressure then remains constant over time. The secondary units 4 . 6 have steady rotational speeds in the steady state operating state, which via the speed determination units 28 . 30 in the parts 20 . 22 be tapped. Equally stationary is one about the actuators 32 . 34 at the secondary units 4 . 6 set swivel angle. One from each wave 20 respectively 22 output torque is proportional to a product of the accumulator pressure p _s and a geometric displacement V _{g of} the secondary unit. This relationship is illustrated by the relation:
M _d p _s V _g ; with M _d torque, p _s storage pressure and V _g : Geometrical displacement.

The secondary control is used by the corresponding secondary unit 4 . 6 delivered torque over the swing angle of the respective secondary unit 4 . 6 set. In other words, according to the currently impressed storage pressure, the displacement (swing angle or eccentricity) of the secondary units 4 . 6 adjusted so that sufficient torque is generated by them to a desired speed or velocity profile of the waves 20 . 22 to reach. The torque generated in this way depends only on the accumulator pressure and the displacement of the secondary unit and not on the speed of the secondary unit 4 . 6 ,

In a practical interpretation of a secondary unit is often in a range of high speed or speed of the individual secondary units 4 . 6 no more torque required. Consequently, no high or maximum high storage pressure must be made available at a high current or instantaneous speed. At this point, the erfindungemäße configuration of the control unit 10 at. For a better understanding, consider now 2 . 3 and 4 , Although the characteristics shown therein refer to the first embodiment, in principle, the following considerations apply to any secondary unit and thus for all embodiments. The description will now be given by way of example with reference to the secondary unit 4 (see. 1 such as 5 and 6 ).

2 shows a torque setpoint characteristic of the secondary unit 4 depending on their speed and a pressure setpoint characteristic of the secondary unit proportional to the torque setpoint characteristic 4 depending on the speed.

Both diagrams according to 2 represent a required characteristic curve, as he used to design the secondary unit 4 for their specific area of application. In 2 on the left is the secondary unit 4 to be provided maximum torque as a function of the speed or the rotational speed of the secondary unit 4 shown. It can be clearly seen that, starting from a speed or zero speed, the maximum required torque M _{max is} initially to be kept constant in a specific speed range, so that, for example, one of the secondary unit 4 driven consumer 24 (see. 1 such as 5 and 6 ) experiences a constant acceleration in this area. From a speed V ₁ or one of these corresponding speed is from the secondary unit 4 with increasing speed or speed no such high maximum torque M _max required more. It instead decreases with increasing speed. As already stated above, the maximum torque M _{max is} dependent on the maximum geometric displacement of the secondary unit 4 and the system pressure or storage pressure. Assuming that the geometric displacement is kept constant, it follows from the required torque curve according to 2 on the left, a corresponding course of the accumulator pressure as a function of the speed or rotational speed of the secondary unit 4 in 2 right.

3 additionally shows a torque characteristic of the secondary unit 4 depending on the speed of the secondary unit 4 as they are under the exclusive use of a hydrostatic accumulator 8th (see. 1 . 5 and 6 ) results as a pressure medium source or pressure medium sinks, as well as a proportional to this torque curve storage pressure curve as a function of speed.

Furthermore, the above-described relationship M _d ~ p _s × V _g applies, or the torque is proportional to the accumulator pressure. In the 3 shown characteristics apply both in engine operation of the secondary unit 4 when pressure medium from the hydrostatic accumulator 8th to the secondary unit 4 as well as in the generator or pump mode, if via the secondary unit 4 for example, the consumer 24 is braked and pressure medium from the tank T (see. 1 . 5 and 6 ) in the hydrostatic accumulator 8th is encouraged.

In the 2 shown pressure setpoint characteristic and the in 3 shown storage pressure characteristic of the secondary unit 4 are in a diagram according to 4 shown together. Therein, the velocity V or the rotational speed is on the abscissa and the associated nominal torque of the secondary unit on the ordinate 4 or the associated desired storage pressure of the hydrostatic accumulator 8th applied. Dashed are the original pressure setpoint curve p ₂ according to 2 right and the original accumulator pressure curve p ₁ according to 3 to the right. The pressure setpoint characteristic curve p ₂ shows its striking two-part linear course or the prominent kink in the course. The accumulator pressure characteristic p ₁ has the substantially curved course.

From the two curves p ₁ and p ₂ results in dependence on the speed of the secondary unit 4 a course of a pressure setpoint characteristic of the accumulator pressure shown in solid lines. At a certain instantaneous speed V _{M, this} always maps the higher value of the two characteristic curves p ₁ and p ₂ . For an exemplary instantaneous speed V _M1 according to FIG 4 this results in a maximum necessary accumulator pressure p _max , which on the approximately horizontal section of the original characteristic p ₂ (see. 2 right). On the other hand, for a still higher instantaneous speed V _M2, a maximum necessary accumulator pressure, which is based on the original characteristic p ₁ (cf. 3 right) is arranged.

It should be noted that for each secondary unit used in the embodiments 4 . 6 two pressure characteristics analogous to the pressure characteristics according to 2 and 3 created and in a pressure setpoint characteristic according to 4 can be summarized. Then assign each secondary unit 4 . 6 the embodiments shown an individual pressure setpoint characteristic of the accumulator pressure in dependence on the instantaneous speed. According to the invention is in the control unit 10 the embodiments shown for each secondary unit 4 . 6 this pressure setpoint characteristic according to 4 saved.

The regulation according to the invention by the control unit 10 will be described below by way of example with reference to the first embodiment 1 described. It is assumed that during a previous hydrostatic braking by the secondary unit 4 the accumulator pressure or the pressure in the working line 14 was charged to 260 bar. Both consumers 24 and 26 stand still and the tilt angle of the secondary units 4 . 6 are turned back to zero. Also the primary unit 2 has a tilt angle of zero. To simplify the description, it is assumed that the consumer 26 continue to stand still.

To the control unit 10 Now a request is made to the consumer 24 to accelerate. For this purpose, the control unit transmits 10 a control signal via a signal line 40 to the actuator 32 the secondary unit 4 and causes an increase of the swivel angle. Since the accumulator pressure is momentarily constant, the torque M _{d of} the secondary unit increases as a result of this measure in accordance with the proportionality M _d -p _s .V _g 4 so that the consumer 24 is accelerated or the instantaneous speed of the shaft 20 increases. At this time, the consumer will 24 or the secondary unit 4 exclusively from the hydrostatic accumulator 8th existing hydrostatic pressure energy at 260 bar (decreasing tendency) operated. The primary unit works here 2 still with zero stroke. The acceleration of the consumer 24 is maximum, since the tilt angle of the secondary unit 4 are set to maximum value.

Task of the control unit 10 it is now, the accumulator pressure during the acceleration process according to the pressure setpoint characteristic of the secondary unit 4 according to 4 readjust. This is done continuously via a signal line 42 that of the pressure determination unit 36 certain memory pressure to the control unit 10 reported. Equally continuous is via a signal line 44 from the speed determination unit 28 certain speed of the shaft 20 to the control unit 10 reported. In the control unit 10 While the thus detected values of the instantaneous speed and the accumulator pressure with the instantaneous pressure setpoints of the accumulator pressure characteristic are continuously determined according to FIG 4 adjusted.

If the memory pressure measured at the instantaneous speed deviates from the instantaneous pressure setpoint of the accumulator pressure characteristic, then the control unit intervenes 10 about an adjustment of the actuator 32 the secondary unit 4 or about the actuator 38 the primary unit 2 one. The actuator 38 is via a signal line 46 with the control unit 10 connected. As long as the accumulator pressure is greater than the current pressure setpoint according to 4 is, so in 4 above the solid memory pressure characteristic, the primary unit 2 continue with zero stroke or with zero swivel angle or Nullexzentrizität. At this time, the pressure medium supply of the secondary unit takes place 4 exclusively from the hydrostatic accumulator 8th , which leads to a decrease of the accumulator pressure. However, should the accumulator pressure be below the accumulator pressure characteristic for a given instantaneous speed 4 fall, then causes the control unit 10 an adjustment of the actuator 38 in the direction of a swivel angle greater than zero. From this point, the primary unit promotes 2 Pressure medium in the working line 14 , Is this way in the work line 14 supplied pressure medium flow greater than that of the secondary unit at the same time 4 the hydrostatic accumulator 8th withdrawn pressure medium volume flow, so approaches that of the pressure determination unit 36 certain accumulator pressure de current pressure setpoint or the accumulator pressure characteristic according to 4 from the bottom until he has reached this.

With the help of the outlined control strategy or the control unit designed according to the invention 10 becomes the accumulator pressure of the hydrostatic accumulator 8th according to the curve of the instantaneous pressure setpoint according to 4 continuously regulated. It is easy to see that, especially at high speeds or high speeds (in 4 right) the instantaneous pressure set point of the accumulator pressure is significantly smaller than at low speeds. This control strategy thus leads to a speed or speed-dependent specification of the accumulator pressure, whereby at any time or at any instantaneous speed of the Secondary unit 4 or the secondary units 4 . 6 in hydrostatic accumulator enough free volume for the absorption of braking energy is kept. In this way, the hydrostatic circuit 1 be energetically operated particularly efficiently.

Notwithstanding the first embodiment according to 1 shows a second embodiment of a hydrostatic circuit 101 according to 5 a concrete primary unit 102 with a hydrostatic machine designed as an adjustable axial piston machine of a swashplate design 148 on. Its swing angle is about one of the control unit 10 over the signal line 46 controlled setting unit 138 changeable. The hydrostatic machine 148 is designed swing-through and can be driven both in pump mode and in engine operation. According to 5 is the hydrostatic machine 148 over a wave 151 with a motor 150 coupled, over which the machine 148 is drivable. In particular, when the accumulator pressure is higher than the present-time pressure set value in accordance with the accumulator pressure characteristic according to FIG 4 is lower, the prescribed control unit can 10 the machine 148 about the actuator 138 adjusted so that it goes into engine operation and torque to the engine 150 emits. In this way, on the one hand, the accumulator pressure is controlled to its current pressure setpoint and on the other hand, the machine 148 the engine 150 assist in driving other units.

Notwithstanding the two embodiments according to 1 and 5 shows a third embodiment of a hydrostatic circuit 201 according to 6 a primary unit 202 with a hydrostatic pump designed as an adjustable axial piston pump with a swashplate design 252 on. A change in the pressure medium volume flow does not take place in this embodiment via a change in the pivot angle of the pump. Instead, the pump is 248 with a valve block 254 connected to a valve 256 that has over one of the control unit 10 over the signal line 46 controlled setting unit 238 is adjustable. An engine 250 is about a wave 251 with the hydrostatic pump 248 coupled. There are two hydraulic cylinders on the valve block 258 . 260 connected. These are not secondary regulated. With the help of this valve or valve block design of the primary unit 202 is the secondary controlled hydrostatic circuit 201 can be integrated in hydraulic architectures of existing machines.

Disclosed is a secondary-controlled hydrostatic circuit with a primary unit for pressure medium supply, with at least one secondary unit for accelerating or decelerating a load and with a memory through which the hydrostatic circuit, a storage pressure is impressed. By way of a control unit of the hydrostatic circuit, the accumulator pressure in the event that only one secondary unit is present can be regulated to its instantaneous pressure setpoint or, if a plurality of secondary units are present, can be regulated to the highest instantaneous pressure setpoint of the plurality of secondary units.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 4308198 C1 [0005]

Claims (8)

Hydrostatic circuit with a working line ( 14 . 14a . 14b . 14c ) to which an adjustable primary unit ( 2 ; 102 ; 202 ), one or more adjustable secondary units ( 4 . 6 ) and a memory ( 8th ), wherein the hydrostatic circuit ( 1 ; 101 ; 201 ) a memory pressure is impressed, characterized in that via a control unit ( 10 ) the accumulator pressure to an instantaneous pressure setpoint of the one secondary unit or to a highest instantaneous pressure setpoint of the plurality of secondary units ( 4 . 6 ) is controllable. Hydrostatic circuit according to claim 1, wherein in the control unit ( 10 ) the respective instantaneous pressure setpoint of the secondary unit or units ( 4 . 6 ) as a function of a desired speed or an instantaneous speed of the respective secondary unit ( 4 . 6 ) is stored. Hydrostatic circuit according to claim 1 or 2, wherein the control unit ( 10 ) via a respective signal connection ( 44 . 45 ) with a speed determination unit ( 28 . 30 ) of the one or more secondary units ( 4 . 6 ), and with a pressure determination unit ( 36 ) of the memory ( 8th ), and with an actuator ( 38 ; 138 ; 238 ) of the primary unit ( 2 ; 102 ; 202 ) connected is. Hydrostatic circuit according to claim 3, wherein the primary unit ( 102 ) one via the steep unit ( 138 ) adjustable hydrostatic machine ( 148 ) having. Hydrostatic circuit according to claim 3, wherein the primary unit ( 202 ) a hydrostatic pump ( 248 ) and a valve ( 256 ), which via the steep unit ( 238 ) of the primary unit ( 202 ) and about the one in the work line ( 14 ) Promoted pressure medium volume flow is changeable. Hydrostatic circuit according to one of the preceding claims, wherein the control unit ( 10 ) via a respective signal connection ( 40 . 41 ) with an actuating unit ( 32 . 34 ) of the one or more secondary units ( 4 . 6 ) connected is. Hydrostatic circuit according to one of the preceding claims, wherein the one hydrostatic secondary unit or at least one of the plurality of hydrostatic secondary units ( 4 . 6 ) is an axial piston machine or a radial piston machine. Hydrostatic circuit according to one of the preceding claims, wherein the working line ( 14 ) at least one additional memory is connected.

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