Hydraulic system, construction and / or viscous pump and process

Abstract

The invention relates to a hydraulic system (1) for driving a construction and / or high-viscosity pump (50), wherein the hydraulic system (1) comprises: a feed pressure section (3) and a low pressure section (4) for hydraulic fluid (L), a controllable low pressure limiting valve device (5) for variably setting a low pressure range for a low pressure (N) for hydraulic fluid (L) in the low pressure section (4), a controllable feed pressure limiting valve device (6) for variably setting a feed pressure range for a feed pressure (S) of hydraulic fluid (L) in the feed pressure section (3), and a control device (7) configured to jointly control the low pressure limiting valve device (5) and the feed pressure limiting valve device (6) in such a manner as tothat the low-pressure limiting valve device (5) adjusts the low-pressure range and the feed-pressure limiting valve device (6) adjusts the feed-pressure range in a mutually dependent manner.

Description

FIELD OF APPLICATION AND STATE OF THE ART

[0001] The invention relates to a hydraulic system for driving a construction and / or slurry pump. The invention also relates to such a construction and / or slurry pump. Furthermore, the invention relates to a method for operating such a construction and / or slurry pump. TASK AND SOLUTION

[0002] It is an object of the present invention to provide a hydraulic system for driving a construction and / or slurry pump as well as such a construction and / or slurry pump and a method for operating such a construction and / or slurry pump, which have improved properties.

[0003] This problem is solved by the subject matter of the independent patent claims. Preferred embodiments are the subject matter of the dependent patent claims.

[0004] A hydraulic system according to the invention serves to drive a construction and / or slurry pump. The construction and / or slurry pump can be driven by the hydraulic system to convey construction and / or slurry. The hydraulic system has a feed pressure section and a low-pressure section, each for hydraulic fluid. Furthermore, the hydraulic system has a controllable pressure-limiting valve device designed to variably set a low-pressure value range for a low pressure of hydraulic fluid in the low-pressure section. The hydraulic system further has a controllable feed pressure-limiting valve device designed to variably set a feed pressure value range for a feed pressure of hydraulic fluid in the feed pressure section. The hydraulic system further has a control device.The control device is designed to jointly control the low-pressure relief valve device and the boost pressure relief valve device. The control device is designed to jointly control the low-pressure relief valve device and the boost pressure relief valve device such that the low-pressure relief valve device sets the low-pressure value range, in particular the prevailing low pressure within the low-pressure value range, and the boost pressure relief valve device sets the boost pressure value range, in particular the prevailing boost pressure within the boost pressure value range, in a mutually dependent manner. The hydraulic system can have a closed hydraulic circuit for hydraulic fluid, wherein the closed hydraulic circuit comprises the boost pressure section and the low-pressure section.The hydraulic circuit of the hydraulic system expediently comprises at least one hydraulic line, in particular a pipe and / or a hose. The low-pressure relief valve device and the feed pressure relief valve device can be coupled together for their joint control. At least one of the low-pressure relief valve device and the feed pressure relief valve device can expediently be electrically and / or hydraulically controlled by the control device. Advantageously, the hydraulic system enables demand-based adjustment of the feed pressure and / or the low pressure to enable particularly energy-efficient drive of the construction and / or slurry pump.In particular, the feed pressure and / or the low pressure can be reduced by means of the hydraulic system by appropriately adjusting the low pressure value range and / or the feed pressure value range in order to reduce power losses and thus minimize energy consumption of the construction and / or slurry pump.

[0005] The low-pressure relief valve device is expediently designed for automatic and / or controllable adjustment of the low-pressure value range, in particular during operation of the hydraulic system, in particular during operation of the construction and / or sludge pump. Alternatively or additionally, the feed pressure relief valve device is expediently designed for automatic and / or controllable adjustment of the feed pressure value range, in particular during operation of the hydraulic system, in particular during operation of the construction and / or sludge pump.

[0006] The hydraulic system according to the invention can advantageously enable a needs-based, i.e. adaptive, setting, in particular a reduction, of an upper limit value for the low-pressure value range and / or for the boost pressure value range. A boost pump of the hydraulic system for feeding the boost pressure section with hydraulic fluid at the boost pressure can overcome an upper limit of the boost pressure value range and / or work against it. In this way, needs-based energy consumption of the boost pump, in particular a reduction in the energy consumption of the boost pump, can be achieved, which can have a beneficial effect on the energy consumption of the hydraulic system. The boost pressure can be generated by means of the boost pump of the hydraulic system. The boost pump can therefore be designed to feed the hydraulic system with hydraulic fluid.The feed pressure value range for the feed pressure, for example, ranges from 8 to 40 bar, in particular from 8 to 34 bar.

[0007] The term “configured” can be used synonymously with the term “trained”.

[0008] The terms “comprises” or “has” can be used synonymously with each other and with the term “comprises”.

[0009] In this context, “control” can mean “steer” and / or “regulate”.

[0010] Building material can include, in particular, mortar, cement, screed, concrete, plaster, and / or bulk construction material, such as sand, gravel, and / or gravel. Additionally or alternatively, thick material can include, in particular, sludge.

[0011] The hydraulic system can expediently comprise a container, in particular a tank, for storing hydraulic fluid. The feed pump can be designed to feed hydraulic fluid into the feed pressure section from the container. Additionally or alternatively, the feed pump can be a constant flow pump. Additionally or alternatively, the feed pump can be designed for direct and / or indirect feeding into the feed pressure section.

[0012] In an embodiment of the invention, the control device is designed to jointly control the low-pressure relief valve device and the feed pressure relief valve device as a function of at least one operating parameter of the hydraulic system and / or hydraulic fluid. The at least one operating parameter can be a drive state, a drive flow, a drive pressure and / or a drive speed. In particular, the drive state can be an active, i.e. driven, state or an inactive, i.e. non-driven, drive state, in particular of the construction and / or slurry pump. Additionally or alternatively, the drive flow and / or the drive pressure can each have a, in particular variable, value or amount and / or be an operating parameter of the hydraulic fluid. Further additionally or alternatively, the drive speed can have a, in particular variable, value or amount.It can have a certain value and / or be an operating parameter of the feed pump and / or drive motor, if present. The working pressure, which can also be referred to as "high pressure" in contrast to low pressure, is, for example, 0 to 1,000 bar, in particular 0 to 400 bar.

[0013] In an embodiment of the invention, the low-pressure relief valve device and the boost pressure relief valve device are jointly hydraulically controllable, in particular pilot-controlled. The control device comprises one, in particular a single, electrically controllable control valve device. The control valve device is designed for joint hydraulic control, in particular pilot control, of the low-pressure relief valve device and the boost pressure relief valve device. The electrically controllable control valve device can be a pilot valve device. The control valve device can communicate fluidically with a hydraulic control line, wherein the low-pressure relief valve device and the boost pressure relief valve device communicate fluidically with each other via the same control line.

[0014] In an embodiment of the invention, the low-pressure value range extends from a minimum of 2.5 bar, in particular from a minimum of 5 bar, in particular from a minimum of 10 bar, in particular from a minimum of 15 bar, to a maximum of 40 bar, in particular up to a maximum of 35 bar, in particular up to a maximum of 30 bar, in particular up to a maximum of 25 bar. The low-pressure value range and the feed pressure value range can be coordinated such that the low pressure is, for example, 1 to 4 bar lower than the feed pressure.

[0015] In a further embodiment of the invention, the low-pressure relief valve device comprises a controllable proportional pressure relief valve designed for continuously adjusting the low-pressure value range. In particular, the proportional pressure relief valve of the low-pressure relief valve device is designed for automatically adjusting the low-pressure value range. In particular, the proportional pressure relief valve of the low-pressure relief valve device is controllable by means of the control device. Alternatively or additionally, the feed pressure relief valve device comprises a controllable proportional pressure relief valve designed for continuously adjusting the feed pressure value range. In particular, the proportional pressure relief valve of the feed pressure relief valve device is designed for automatically adjusting the feed pressure value range.In particular, the proportional pressure relief valve of the feed pressure relief valve device can be controlled by means of the control device.

[0016] The proportional pressure relief valve of the low-pressure relief valve device and / or the feed pressure relief valve device can expediently be a proportional pressure control valve and / or be referred to as a proportional pressure control valve.

[0017] In a further embodiment of the invention, the hydraulic system comprises a variably adjustable, in particular adjustable, drive pump. The drive pump is designed to generate the variable drive flow with a variable drive pressure of hydraulic fluid in at least one drive pressure section of the hydraulic system. Furthermore, the hydraulic system comprises at least one hydraulically based, in particular electrically controllable, actuator, which is designed to variably adjust, in particular set, the drive pump by means of a variable actuating pressure of hydraulic fluid. The feed pressure section is designed to supply hydraulic fluid to the at least one actuator at the set feed pressure for the actuating pressure.The control device is designed to control the at least one actuator, in particular as a function of the at least one operating parameter, in such a way that the at least one actuator adjusts the drive pump, in particular variably, to generate the variable drive flow with the variable drive pressure of hydraulic fluid in the at least one drive pressure section.

[0018] In particular, the drive pressure section can be different from the feed pressure section. In particular, the feed pressure section can be designed to feed hydraulic fluid into the drive pressure section by means of at least one feed check valve of the hydraulic system. The feed pump can thus be designed for indirect, ie, indirect, feeding into the drive pressure section.

[0019] In a further embodiment of the invention, the drive pump is an axial piston pump with a variably adjustable swash plate. The at least one actuator is designed for variably adjusting the swash plate. In particular, the axial piston pump has a variably adjustable, in particular adjustable, displacement. The actuator can be designed for, in particular automatically, variably adjusting the displacement. In particular, a pivot angle of the swash plate can be dependent on the operating parameter. In particular, the control device can be designed for, in particular automatically, determining and / or ascertaining and / or calculating the pivot angle, in particular its value, as a function of the at least one operating parameter.

[0020] In a further embodiment of the invention, the hydraulic system comprises at least one drive cylinder and an associated drive piston, in particular guided in the drive cylinder. The drive pump is designed to generate the drive flow of hydraulic fluid by variably moving the at least one drive piston, in particular in the drive cylinder. In particular, the hydraulic system can have at least one pump line. The drive pump and the drive cylinder can be connected by means of the pump line for a flow of hydraulic fluid, in particular between the drive pump and the drive cylinder. Additionally or alternatively, the drive piston can be designed to be pressurized with hydraulic fluid.Furthermore, or alternatively, the control device can be designed to control the movement of the drive piston, in particular automatically, depending on the at least one operating parameter.

[0021] In a further embodiment of the invention, the hydraulic system has at least two drive cylinders and at least two respectively associated drive pistons, in particular guided in the respective drive cylinder. Furthermore, the hydraulic system has a rocker line for hydraulic fluid. The drive pump and the two drive cylinders can form a closed drive circuit for hydraulic fluid by means of the rocker line. The two drive pistons are coupled by means of the rocker line, in particular in phase opposition. In particular, the two drive cylinders can be connected by means of the rocker line for a flow of hydraulic fluid, in particular between the drive cylinders. Additionally or alternatively, the hydraulic system can have at least two pump lines.The drive pump and the two drive cylinders can form the closed drive circuit for hydraulic fluid by means of the rocker line and the two pump lines. In particular, the drive pump and one of the two drive cylinders can be connected by means of one of the two pump lines for a flow of hydraulic fluid, in particular between the drive pump and the drive cylinder. The drive pump and another of the two drive cylinders can be connected by means of another of the two pump lines for a flow of hydraulic fluid, in particular between the drive pump and the drive cylinder. Furthermore, additionally or alternatively, the drive pump or the closed drive circuit can have a high-pressure side and a low-pressure side, in particular during operation of the hydraulic system, in particular during the drive of the construction and / or slurry pump.In particular, the drive pressure—as already mentioned above—can be referred to as high pressure, in particular the high pressure side. The low pressure can be created or generated by the feed pump. The drive pressure or high pressure or its value can be greater than the low pressure or its value. In particular, "closed drive circuit" can refer to a flow of hydraulic fluid from the drive pump, in particular its high pressure side, through one pump connection, one drive cylinder, the rocking connection, the other drive cylinder, the other pump connection to the drive pump, in particular its low pressure side.

[0022] In a further embodiment of the invention, the low-pressure relief valve device is designed to flush hydraulic fluid out of the low-pressure section by variably adjusting the low-pressure value range. Alternatively or additionally, the boost pressure relief valve device is designed to flush hydraulic fluid out of the boost pressure section by variably adjusting the boost pressure value range. In particular, hydraulic fluid can be flushed out to prevent it from leaving the low-pressure value range and / or the boost pressure value range at an upper limit of the low-pressure value range and / or the boost pressure value range.

[0023] In a further embodiment of the invention, the hydraulic system has at least one measuring sensor designed to measure at least one property, in particular a pressure, of the hydraulic system and / or hydraulic fluid. The control device is designed to determine at least one operating parameter depending on the measured property.

[0024] A construction and / or slurry pump according to the invention comprises a construction and / or slurry conveying device. The construction and / or slurry conveying device is designed to convey construction and / or slurry. Furthermore, the construction and / or slurry pump comprises a hydraulic system according to the invention as described above. The hydraulic system is designed to drive the construction and / or slurry conveying device. The above-explained advantages of the hydraulic system according to the invention also apply to the construction and / or slurry pump according to the invention with such a hydraulic system.

[0025] The construction and / or thick matter pump can expediently be designed as a mobile device, in particular as a car construction and / or thick matter pump.

[0026] A method according to the invention serves to operate a construction and / or slurry pump according to the invention as described above. The construction and / or slurry pump according to the invention can therefore be operated according to the method according to the invention. The method comprises a step a), according to which the drive flow and / or the drive pressure of hydraulic fluid in the drive pressure section of the hydraulic system is varied, in particular by adjusting the variably adjustable drive pump of the hydraulic system. The method also comprises a step b), according to which - if a temporal rate of change of the drive flow and / or the drive pressure is greater in magnitude than a predetermined threshold value - the upper limit of the low-pressure value range is set to a predetermined maximum value.The method further comprises a step c), according to which – if the rate of change over time of the drive flow and / or the drive pressure is equal to or less than the predetermined threshold value – the upper limit of the low-pressure value range is lowered. In this way, the low pressure can be variably adjusted to a particularly energy-efficient level during operation of the construction and / or slurry pump.

[0027] In an embodiment of the invention, in particular of the method according to the invention, the drive flux is varied in an oscillating manner, particularly with a zero crossing. This can enable the antiphase adjustment of two drive pistons in the associated drive cylinders of the construction and / or slurry pump.

[0028] In particular, the construction and / or slurry pump, in particular the construction and / or slurry, can have at least one, in particular variable, delivery parameter, in particular with a value or amount. In particular, the at least one delivery parameter can be a delivery state, a delivery flow and / or a delivery pressure. Additionally or alternatively, the at least one operating parameter can be dependent on the at least one delivery parameter and / or must have a predetermined or required value to achieve the delivery parameter, in particular the one desired by the user. In particular, the drive state can be dependent on the delivery state, the drive flow on the delivery flow and / or the drive pressure on the delivery pressure, if present. In other words: the control unit can be used for a, in particular automatic, determination or ascertainment, in particular a calculation, of the at least one operating parameter orits value as a function of the at least one conveying parameter. Furthermore, or alternatively, the control unit may comprise a control panel for operating the construction and / or slurry pump or the hydraulic system, in particular an input device for user input or user selection of the at least one conveying parameter or its value. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Further advantages and features of the invention will become apparent from the claims and the following description of a preferred embodiment of the invention, which is illustrated with reference to the drawings. Like reference numerals refer to like, similar, or functionally identical components.

[0030] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0031] The only Fig. 1 shows schematically a circuit diagram for an embodiment of a construction and / or thick matter pump according to the invention with an embodiment of a hydraulic system according to the invention when carrying out a method according to the invention for operating the construction and / or thick matter pump. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] A construction and / or slurry pump 50 according to the invention has a construction and / or slurry conveying device 51. The construction and / or slurry conveying device 51 is designed to convey construction and / or slurry. Furthermore, the construction and / or slurry pump 50 has a hydraulic system 1 according to the invention, which is designed to drive the construction and / or slurry conveying device 51. The construction and / or slurry pump 50 can be driven by driving the construction and / or slurry conveying device 51. Accordingly, the hydraulic system 1 is designed to drive the construction and / or slurry pump 50.

[0033] The hydraulic system 1 has a feed pressure section 3 and a low pressure section 4, each for hydraulic fluid L. The feed pressure section 3 and the low pressure section 4 can be part of a, in particular closed, hydraulic circuit for hydraulic fluid L of the hydraulic system 1.

[0034] The hydraulic system 1 also has a controllable low-pressure relief valve device 5. The controllable low-pressure relief valve device 5 serves to variably adjust a low-pressure value range for a low pressure N of hydraulic fluid L in the low-pressure section 4.

[0035] In addition, the hydraulic system 1 has a controllable feed pressure relief valve device 6. The controllable feed pressure relief valve device 6 serves to variably set a feed pressure value range for a feed pressure S of hydraulic fluid L in the feed pressure section 3.

[0036] The hydraulic system 1 further comprises a control device 7. The control device 7 is designed to jointly control the low-pressure relief valve device 5 and the boost pressure relief valve device 6 such that the low-pressure relief valve device 5 sets the low-pressure value range and the boost pressure relief valve device 6 sets the boost pressure value range dependent on one another. The low-pressure relief valve device 5 and the boost pressure relief valve device 6 can be coupled to one another for their joint control.

[0037] The hydraulic system 1 in the present case has a feed pump 19, which is designed to supply the feed pressure section 3 with hydraulic fluid at feed pressure S. The hydraulic system 1 in the present case also comprises a reservoir 20, in particular a storage container or tank, for hydraulic fluid L. The feed pump 19 can be supplied with hydraulic fluid L from the reservoir 20. The hydraulic system 1 has, for example, a feed check valve 21, which can fluidically connect the feed pressure section 3 to the low-pressure section 4, in particular unidirectionally. The hydraulic system 1 in the present case also has an alternating flushing valve 22, to which the low-pressure section 4 is fluidically connected. The alternating flushing valve 22 can be designed to be controllable for fluidically connecting the low-pressure section 4 to the low-pressure relief valve device 5.

[0038] The hydraulic system 1 has, for example, a valve 23, by means of which a supply of hydraulic fluid L to a rocking oil discharge valve 24 of the hydraulic system 1 can be adjusted, in particular shut off. Furthermore, the hydraulic system 1 in this case has a rocking oil discharge throttle 25, which can be supplied with hydraulic fluid L by means of another rocking oil discharge valve 24. Furthermore, the hydraulic system 1 in this case has a flushing line 26, which can be part of the low-pressure section 4 and which is designed for the fluid-conducting connection of the low-pressure section 4 to the alternating flushing valve 22.

[0039] In addition, the hydraulic system 1 in the present case has control lines 27, each for controlling the alternating flushing valve 22 as well as the low-pressure relief valve device 5 and the feed pressure relief valve device 6. For example, the hydraulic system 1 has a control pressure line 28 for controlling actuators 13 of the hydraulic system 1. In the present case, the hydraulic system 1 has two, in particular hydraulic, control lines 27 for, in particular automatically, controlling the alternating flushing valve 22.

[0040] For example, the control device 7 is designed to jointly control the low-pressure relief valve device 5 and the feed pressure relief valve device 6 depending on at least one operating parameter B of the hydraulic system 1. Alternatively or additionally, the control device 7 is designed to jointly control the low-pressure relief valve device 5 and the feed pressure relief valve device 6 depending on at least one operating parameter B of hydraulic fluid L. In this case, the at least one operating parameter B is a drive state, a drive flow, a drive pressure A, and / or a drive speed.

[0041] The feed pressure S can be generated by means of the feed pump 19 of the hydraulic system 1. The feed pump 19 is designed to feed the hydraulic system 1 with hydraulic fluid L. The feed pressure range for the feed pressure S ranges, for example, from 8 to 40 bar, in particular from 8 to 34 bar. The working pressure A, which can be referred to as “high pressure” compared to the low pressure N, is, for example, 0 to 1,000 bar, in particular 0 to 400 bar. The low pressure N can be 1 to 4 bar lower than the feed pressure S. For example, a lower limit of the low pressure range is 2.5 bar, in particular 5 bar, in particular 10 bar, in particular 15 bar. An upper limit of the low pressure range can be, for example, 40 bar, in particular 35 bar, in particular 30 bar, in particular 25 bar.

[0042] For example, the low-pressure relief valve device 5 and the boost pressure relief valve device 6 are jointly hydraulically controllable. In this case, the low-pressure relief valve device 5 and the boost pressure relief valve device 6 are jointly hydraulically pilot-controlled. The control device 7 comprises, for example, an electrically controllable control valve device 8. In this case, the control device 7 comprises a single electrically controllable control valve device 8. The control valve device 8 is designed, for example, for the joint hydraulic control of the low-pressure relief valve device 5 and the boost pressure relief valve device 6. In this case, the control valve device 8 is designed for the joint hydraulic pilot-control of the low-pressure relief valve device 5 and the boost pressure relief valve device 6.

[0043] The electrically controllable control valve device 8 may be a pilot valve device. The control valve device 8 may fluidically communicate with one of the control lines 27, with the low-pressure relief valve device 5 and the feed pressure relief valve device 6 fluidically communicating with each other via the same control line 7.

[0044] The low-pressure relief valve device 5 in this case has a controllable proportional pressure relief valve 9. The controllable proportional pressure relief valve 9 of the low-pressure relief valve device 5 is designed, for example, for continuously adjusting the low-pressure value range. Alternatively or additionally, the feed pressure relief valve device 6—as in the present case—has a, in particular further, controllable proportional pressure relief valve 10. The controllable proportional pressure relief valve 10 of the feed pressure relief valve device 6 is designed, for example, for continuously adjusting the feed pressure value range.

[0045] The hydraulic system 1 has, for example, a variably adjustable drive pump 11. The variably adjustable drive pump 11 is designed in this case to generate a variable drive flow with a variable drive pressure A of hydraulic fluid L in at least one drive pressure section 12 of the hydraulic system 1. The hydraulic system 1 has, for example, at least one hydraulic-based actuator 13, which is designed to variably adjust the drive pump 11 by a variable actuating pressure of hydraulic fluid L. In the present case, two such hydraulic-based actuators 13 are present. The feed pressure section 3 is designed, for example, to hydraulically supply the at least one actuator 13 with hydraulic fluid L at the set feed pressure S for the actuating pressure.The control device 7 is designed, for example, to control the at least one actuator 13 such that the at least one actuator 13 adjusts the drive pump 11 to generate the variable drive flow with the variable drive pressure A of hydraulic fluid L in the at least one drive pressure section 12. In the present case, the control device 7 is designed to control the at least one actuator 13 depending on the at least one operating parameter B.

[0046] The drive pump 11 is an axial piston pump 14 with a variably adjustable swash plate. The at least one actuator 13 is designed, for example, for variably adjusting the swash plate.

[0047] The hydraulic system 1 comprises, for example, at least one drive cylinder 15 and an associated drive piston 16. The drive pump 11 is designed to generate the drive flow of hydraulic fluid L by variably moving the at least one drive piston 16. In the present case, the hydraulic system 1 has two drive cylinders 15 and associated drive pistons 16, which are coupled to one another by means of a rocker line 17 for hydraulic fluid L.

[0048] For example, the low-pressure relief valve device 5 is designed to flush hydraulic fluid L out of the low-pressure section 4 by variably adjusting the low-pressure value range. Alternatively or additionally, the feed pressure relief valve device 6—as in the present case—is designed to flush hydraulic fluid L out of the feed pressure section 3 by variably adjusting the feed pressure value range.

[0049] The hydraulic system 1 can comprise at least one measuring sensor 18, which is designed to measure at least one property, in particular a pressure, of the hydraulic system 1 and—alternatively or additionally—of hydraulic fluid L. The control device 7 is designed to determine the at least one operating parameter B as a function of the measured property. In this way, closed-loop control of the low-pressure relief valve device 5 and / or the feed pressure relief valve device 6 can be achieved by feedback of the measured property via the operating parameter B determined therefrom.

[0050] The construction and / or slurry pump 50 is operated according to a method according to the invention. The method comprises a step a), according to which the drive flow and—alternatively or additionally—the drive pressure A of hydraulic fluid L in the drive pressure section 12 of the hydraulic system 1 are varied. In the present case, the drive flow and, alternatively or additionally, the drive pressure A in the drive pressure section 12 are varied by adjusting the variable-displacement drive pump 11. The method also comprises a step b), according to which—if a time rate of change, in particular a first time derivative, of the drive flow and, alternatively or additionally, of the drive pressure A is greater in magnitude than a predetermined threshold value—the upper limit of the low-pressure value range is set to a predetermined maximum value.The method further comprises a step c), according to which—if the temporal rate of change of the drive flow and / or the drive pressure A is equal to or less than the predetermined threshold value—the upper limit of the low-pressure value range is lowered. The drive flow can be varied in an oscillating manner, for example, with a zero crossing as in the present case.

[0051] The drive pump 11 has, for example, a high-pressure side and a low-pressure side, which are cyclically exchanged with each other during operation of the hydraulic system 1 and / or the construction and / or slurry pump 50. The drive pressure A is, for example, higher than the upper limit of the low-pressure value range. If in Fig. 1 the high pressure side is at the top, then the low pressure side is at the bottom, and vice versa. This is indicated by the slash between the reference symbols N and A. If the high pressure side is in Fig. 1 is at the top, hydraulic fluid L flows with the drive pressure A from the drive pump 11 to the Fig. 1 drive cylinder 15 shown below. This forms a hydraulic connection between the drive pump 11 and the Fig. 1 drive cylinder 15 shown below, in particular at least partially, the drive pressure section 12. Thus, the drive cylinder 15 shown in Fig. 1 drive piston shown below 16 in Fig. 1 to the right. Hydraulic fluid L, especially with a rocking pressure, flows from the Fig. 1 drive cylinder 15 shown below through the swing line 17 to the Fig. 1 drive cylinder 15 shown above. The swing line 17 and the drive cylinder 15 can form, in particular at least partially, a swing pressure section. Thus, the Fig. 1 drive piston shown above 16 in Fig. 1 to the left. Hydraulic fluid L with low pressure N flows from the Fig. 1 drive cylinder 15 shown above to the drive pump 11. The connection between the drive pump 11 and the Fig. 1 drive cylinder 15 shown above, in particular at least partially, form the low-pressure section 4. The feed pressure section 3 feeds the low-pressure section 4, in particular by means of the Fig. 1 feed check valve 21 shown above.

[0052] When the drive pistons 16 have reached their end positions, the high-pressure side and the low-pressure side of the drive pump 11 are swapped. Then the high-pressure side is in Fig. 1 at the top and the low pressure side at the bottom. Thus, the Fig. 1 the drive piston 16 shown below in Fig. 1 to the left and the drive piston 16 shown above to the right.

[0053] For example, hydraulic fluid L can be flushed out of the hydraulic system 1, in particular into the reservoir 20, by means of the low-pressure relief valve device 5 and / or by means of the feed pressure relief valve device 6.

[0054] For example, a portion of the hydraulic fluid L flows out of the boost pressure section 3 into the low pressure section 4. Another portion of the hydraulic fluid L can be flushed out of the boost pressure section 3.

[0055] For example, a portion of the hydraulic fluid L flows from the low-pressure section 4 to the drive pump 11. Another portion of the hydraulic fluid L can be flushed out of the low-pressure section 4.

[0056] The low-pressure section 4 and the low-pressure relief valve device 5 are connected by means of the alternating flushing valve 22 for a flow of hydraulic fluid L. If in Fig.1 the low-pressure section 4 is arranged at the top, hydraulic fluid L can flow from the low-pressure section 4 through the alternating flushing valve 22 to the low-pressure relief valve device 5.

[0057] For example, the hydraulic system 1 has two flushing lines 26 for hydraulic fluid L. The low-pressure section 4 and the drive pressure section 12 are each connected to the alternating flushing valve 5 via one of the flushing lines 26. The alternating flushing valve 5 is designed, for example, to connect the flushing line 26 to the low-pressure relief valve device 5, in particular for a flow of hydraulic fluid L from the respective flushing line 26 to the low-pressure relief valve device 5, which has a relatively lower pressure than the other flushing line 26.

[0058] The construction and / or high-density material conveying device 51 has, for example, at least one, in particular two, conveying cylinders and one, in particular two, associated conveying pistons, in particular arranged in the conveying cylinder. In particular, the at least one conveying cylinder is designed for construction and / or high-density material. The at least one conveying cylinder can be designed to pressurize construction and / or high-density material. The hydraulic system 1 can have at least one, in particular two, piston rods. The at least one piston rod can be designed to couple or transmit the movement of the at least one drive piston 16 to the at least one conveying piston. In particular, the at least one piston rod is attached to the at least one drive piston 16 or to the at least one conveying piston. In addition, the construction and / or high-density material conveying device 51 can have a pipe switch system.

[0059] The construction and / or thick matter conveying device 51 can thus have conveying cylinders with variable-volume conveying chambers. To change the volumes of the conveying chambers, in particular in opposite directions, each of the conveying cylinders can be assigned an adjustable conveying piston. The construction and / or thick matter conveying device 51 can also comprise an S-shaped pipe switch, in particular an S-pipe, which is fluidly connected at one end to a pressure port acting as a construction and / or thick matter pump outlet. The pipe switch can be arranged in a storage chamber that can be filled with construction and / or thick matter from above for storing construction and / or thick matter. The pipe switch can be rotatably mounted at one end on the pressure port within the storage chamber. The variable-volume conveying chambers can open into the storage chamber.The pipe switch can be pivoted relative to the conveying chambers in the storage chamber such that it can be alternately connected to one of the conveying chambers for the conveying of building materials and / or high-density material. In this way, the counteraction of the pivoting of the pipe switch and a change in the volume of the conveying chambers allows the building materials and / or high-density material located in the storage chamber to be alternately sucked in by the conveying chambers and pumped out through the conveying chambers, through the pipe switch, and via the discharge nozzle.

[0060] The invention can provide an advantageous hydraulic system 1 for a construction and / or slurry pump 50 as well as an advantageous construction and / or slurry pump 50 comprising such a hydraulic system 1, which respectively have improved properties, in particular enabling a saving of energy or power.

Claims

[1] Hydraulic system (1) for driving a construction and / or viscous material pump (50), wherein the hydraulic system (1) comprises: - a feed pressure section (3) and a low pressure section (4) for hydraulic fluid (L), - a controllable low-pressure limiting valve device (5) for variably setting a low-pressure value range for a low pressure (N) of hydraulic fluid (L) in the low-pressure section (4), - a controllable feed pressure limiting valve device (6) for variably setting a feed pressure value range for a feed pressure (S) of hydraulic fluid (L) in the feed pressure section (3), and - a control device (7) designed to jointly control the low-pressure limiting valve device (5) and the feed-pressure limiting valve device (6) such that the low-pressure limiting valve device (5) adjusts the low-pressure value range and the feed-pressure limiting valve device (6) adjusts the feed-pressure value range in a dependent manner. [2] Hydraulic system (1) according to the preceding claim, - wherein the control device (7) is configured to jointly control the low-pressure limiting valve device (5) and the supply pressure limiting valve device (6) depending on at least one operating parameter (B) of the hydraulic system (1) and / or hydraulic fluid (L), - in particular wherein at least one operating parameter (B) is a drive state, a drive flow, a drive pressure (A) and / or a drive speed. [3] Hydraulic system (1) according to any one of the preceding claims, - wherein the low-pressure limiting valve device (5) and the feed-pressure limiting valve device (6) are jointly hydraulically controllable, in particular pilot-operable, - wherein the control device (7) has an, in particular a single, electrically controllable control valve device (8), wherein the control valve device (8) is designed for common hydraulic control, in particular pilot control, of the low pressure limiting valve device (5) and the feed pressure limiting valve device (6). [4] Hydraulic system (1) according to any one of the preceding claims, wherein the low-pressure range extends from a minimum of 2.5 bar, in particular a minimum of 5 bar, in particular a minimum of 10 bar, in particular a minimum of 15 bar, to a maximum of 40 bar, in particular a maximum of 35 bar, in particular a maximum of 30 bar, in particular a maximum of 25 bar. [5] Hydraulic system (1) according to any one of the preceding claims, - wherein the low-pressure relief valve device (5) comprises a controllable proportional pressure relief valve (9) designed for continuous adjustment of the low-pressure value range, and / or - wherein the feed pressure limiting valve device (6) has a controllable proportional pressure limiting valve (10) designed for continuous adjustment of the feed pressure range. [6] Hydraulic system (1) according to any of the preceding claims, comprising - a variably adjustable drive pump (11) designed to generate a variable drive flow with a variable drive pressure (A) of hydraulic fluid (L) in at least one drive pressure section (12) of the hydraulic system (1), and - at least one hydraulic pressure-based actuator (13) designed to variably adjust the drive pump (11) by means of a variable actuating pressure of hydraulic fluid (L), - wherein the supply pressure section (3) is designed to supply the at least one actuator (13) with hydraulic fluid (L) at the set supply pressure (S) for the actuating pressure, - wherein the control device (7) is designed to control the at least one actuator (13) in particular depending on at least one operating parameter (B) such that the at least one actuator (13) adjusts the drive pump (11) to generate the variable drive flow with the variable drive pressure (A) of hydraulic fluid (L) in the at least one drive pressure section (12). [7] Hydraulic system (1) according to the preceding claim, - wherein the drive pump (11) is an axial piston pump (14) with a variably adjustable swashplate, - wherein at least one actuator (13) is designed for variable adjustment of the swashplate. [8] Hydraulic system (1) according to one of the two preceding claims, comprising - at least one drive cylinder (15) and one associated drive piston (16), - wherein the drive pump (11) is designed to generate the drive flow of hydraulic fluid (L) by variably moving the at least one drive piston (16). [9] Hydraulic system (1) according to the preceding claim, comprising - at least two drive cylinders (15) and each associated drive piston (16), and - a swing line (17) for hydraulic fluid (L), - wherein the two drive pistons (16) are coupled by means of the swing line (17). [10] Hydraulic system (1) according to any one of the preceding claims, wherein the low-pressure limiting valve device (5) is designed to flush hydraulic fluid (L) out of the low-pressure section (4) by variably adjusting the low-pressure value range, and / or wherein the feed pressure limiting valve device (6) is designed to flush hydraulic fluid (L) out of the feed pressure section (3) by variably adjusting the feed pressure value range. [11] Hydraulic system (1) according to any of the preceding claims, comprising: - at least one measuring sensor (18) designed to measure at least one property, in particular a pressure, of the hydraulic system (1) and / or hydraulic fluid (L), - wherein the control device (7) is designed to determine at least one operating parameter (B) depending on the measured property. [12] Construction and / or viscous material pump (50), comprising: - a construction and / or thick material conveying device (51) designed for conveying construction and / or thick material, - a hydraulic system (1) according to one of the preceding claims, designed to drive the construction and / or thick material conveying device (51). [13] Method for operating a construction and / or high-viscosity pump (50) according to the preceding claim, the procedure comprises the following steps: a) Varying a drive flow and / or a drive pressure (A) of hydraulic fluid (L) in a drive pressure section (12) of the hydraulic system (1), in particular by adjusting a variable drive pump (11) of the hydraulic system (1); b) if the rate of change of the drive flow and / or the drive pressure (A) over time is greater in magnitude than a predetermined threshold: setting an upper limit of the low-pressure value range to a predetermined maximum value, c) if the rate of change over time of the drive flow and / or the drive pressure (A) is equal to or less than the predetermined threshold: lowering the upper limit of the low-pressure range. [14] Method according to the preceding claim, where the drive flow is varied in an oscillating manner, particularly with zero crossings.

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