Two-cylinder thick matter pump

Abstract

The invention relates to a two-cylinder thick matter pump (111), in particular for a truck-mounted concrete pump (100), comprising: at least one first hydraulic pump (115); two hydraulic drive cylinders (147) which are driven in push-pull mode by the at least one first hydraulic pump (115) in order to drive two delivery pistons and each of which runs in one of two delivery cylinders (148) of the two-cylinder thick matter pump (111), wherein the thick matter delivery rate can be set by adjusting the delivery rate of the at least one first hydraulic pump (115); a second hydraulic pump (117) which charges a switch-over hydraulic accumulator (146); at least one switch-over hydraulic cylinder (145) powered by the switch-over hydraulic accumulator (146); and a thick matter switch-over valve (112) driven by the at least one switch-over hydraulic cylinder (145) for alternately connecting the two delivery cylinders (148) to a thick matter delivery line (164). The delivery rate of the second hydraulic pump (117) can be adjusted depending on the set thick matter delivery rate.

Description

[0001] SHWG1247 15.02.2024 BD / AY Two-cylinder thick matter pump The invention relates to a two-cylinder thick matter pump, in particular for a truck-mounted concrete pump, with at least one first hydraulic pump, two hydraulic drive cylinders driven in push-pull by the at least one first hydraulic pump, which are provided for driving two delivery pistons, each running in one of two delivery cylinders of the two-cylinder thick matter pump, wherein a thick matter delivery rate can be adjusted by adjusting the delivery capacity of the at least one first hydraulic pump, with a second hydraulic pump and with a switchover hydraulic accumulator, wherein the second hydraulic pump is provided to charge the switchover hydraulic accumulator, at least one switchover hydraulic cylinder fed from the switchover hydraulic accumulator and with a thick matter switchover valve driven by the at least one switchover hydraulic cylinder, which is used for alternately connecting the two delivery cylinders witha slurry conveying line. In a truck-mounted concrete pump, a hydraulic pump train consisting of several hydraulic pumps arranged in series is usually used on the construction site to drive the units of the concrete pump structure, for example, a two-cylinder slurry pump, the placing boom, the support, and other units required for operation. To reduce the emission of undesirable exhaust gases and climate-damaging carbon dioxide, it is desirable to also electrically drive truck-mounted concrete pumps on the construction site. There are now concepts for driving the hydraulic pump train of a truck-mounted concrete pump with an electric motor, but with an electrically or hybrid (diesel and electric) driven truck-mounted concrete pump, the problem is that the electrical power provided by an on-board battery and / or a construction site power supply is insufficient in theUsually, this is not sufficient to electrically drive the truck-mounted concrete pump sufficiently or for a sufficiently long period of time for the concrete pumping / delivery process. A truck diesel engine today typically has an output of approximately 300-500 kW, so that there is always sufficient power reserve to drive the units of the truck-mounted concrete pump, which require a maximum drive power of 200-250 kW. For design reasons, several hydraulic pumps arranged in series, a so-called hydraulic pump train, are driven by the power take-off of the diesel engine in a truck-mounted concrete pump. The speed of the diesel engine should be kept as low as possible, but is ultimately based on the power requirements of the truck-mounted concrete pump structure, in particular the concrete pump, because this has the highest power requirements when delivering concrete. The simultaneous drive of all hydraulic pumps inevitably results in all hydraulic pumps, which, in addition to the concrete pump, also drive theThe placing boom, the outriggers, the agitator, the concrete changeover valve, and any other components of the superstructure, are driven at an identical, generally constant speed. This alone results in power losses because the available power of the hydraulic pumps is not drawn constantly, even if some hydraulic pumps can be switched to idle mode by adjusting the delivery rate. Due to the power losses described above when driving a hydraulic pump train, it is necessary to seek ways to reduce these losses in order to use the available electrical drive power as effectively as possible. One of the hydraulic pumps in the hydraulic pump train, the so-called accumulator charging pump, charges a hydraulic accumulator for switching the changeover valve of the two-cylinder slurry pump. The changeover valve must be actuated as quickly as possible (approx. 250-500 ms) by means of one or twoHydraulic cylinders are switched over. This short switching time is necessary because during the switching of the switching valve the delivery cylinders of the two-cylinder slurry pump are short-circuited with each other, which results in a drop in the delivery pressure and should therefore be kept as low as possible. The accumulator charging pump is dimensioned in such a way that, at an assumed diesel engine speed of, for example, 1200 rpm, it fills the hydraulic accumulator so quickly between the switching processes that even at the highest delivery rate of the two-cylinder slurry pump, the hydraulic accumulator fills sufficiently quickly for the switching process. At the highest delivery rate, the switching of the switching valve takes place approximately every two to two and a half seconds, so that the hydraulic accumulator must be refilled in about two seconds. The accumulator charging pump has a simple control system, i.e. when the pressure of the hydraulic accumulator reaches ahas reached the specified value, the pump is switched to idle by reducing the flow rate, or the hydraulic oil pumped by the accumulator charging pump is diverted past the hydraulic accumulator into the hydraulic oil tank. Furthermore, during the actual charging process of the accumulator, the energy consumption of the accumulator charging pump is very high. If a lower flow rate is required, where the switching valve is only switched every five seconds, for example, the accumulator charging pump is driven for approximately three seconds between switching processes without further charging the accumulator, and therefore requires a corresponding drive power even when idling. Therefore, the object of the invention is to provide a two-cylinder high-density solids pump with which the described disadvantages are at least partially eliminated, or with which the available drive energy is used as effectively as possible for the delivery of concrete or high-density solids.This object is achieved by a two-cylinder slurry pump having the features of claim 1, as well as a method for operating a two-cylinder slurry pump according to claim 13. Because the delivery capacity of the second hydraulic pump, which charges the hydraulic switching accumulator, is adjustable depending on the set slurry delivery rate, the drive power of the second hydraulic pump can be reduced if a lower slurry delivery rate is required. This is particularly advantageous if the two-cylinder slurry pump is driven by an electric motor whose drive power is lower than the drive power of an internal combustion engine, which regularly leads to a rather low slurry delivery rate. Power consumption peaks of the second hydraulic pump are also avoided, so that the available drive power can be better used for the actual slurry delivery, i.e., for driving the delivery cylinders.Advantageous embodiments and further developments of the invention emerge from the dependent claims. It should be noted that the features listed individually in the claims can also be combined with one another in any technologically expedient manner and thus demonstrate further embodiments of the invention. It is preferably provided that the delivery capacity of the second hydraulic pump is adjustable such that the switching hydraulic accumulator is completely filled immediately before a switching operation of the thick matter switching valve. By this measure, the maximum power consumption of the hydraulic pump that charges the switching hydraulic accumulator is reduced as best as possible depending on the requested thick matter delivery rate, so that the maximum possible drive power can always be used to drive the delivery cylinders. Advantageously, a control device is designed to control the delivery capacity of the at least onefirst hydraulic pump and the delivery capacity of the second hydraulic pump according to the set thick matter delivery rate. The control device can optimally adjust the delivery capacities of the at least one first and the second hydraulic pump depending on the set thick matter delivery rate and, if necessary, also take into account the available drive power for the hydraulic pumps, so that no short-term power consumption peaks occur that are above the available drive power. According to an advantageous embodiment, the delivery capacity of the second hydraulic pump can be adjusted by adjusting the geometric delivery volume of the second hydraulic pump. This is particularly advantageous if the second hydraulic pump is designed, for example, as an axial piston variable displacement pump, the geometric delivery volume of which can be easily adjusted by adjusting the pivoting angle of the swash plate andso that the delivery capacity of the second hydraulic pump can be easily adapted to the required thick matter delivery rate. In an alternative embodiment, the delivery capacity of the second hydraulic pump can be adjusted by adjusting the drive speed of the second hydraulic pump. This variant is particularly advantageous when the second hydraulic pump is designed as a so-called constant flow pump, e.g. as a cheap gear pump or as a simply constructed axial piston pump without the possibility of adjusting the delivery volume. By adjusting the drive speed, the delivery capacity of this type of hydraulic pump can be easily and inexpensively adjusted. In a further embodiment of the invention, a common drive motor drives the at least one first hydraulic pump and the second hydraulic pump, and the delivery capacity of the at least one first hydraulic pump and the delivery capacity of the second hydraulic pump can be adjusted by adjusting the speed of the drive motor.adaptable. In particular, in the case where the drive motor is an electric motor, the speed of which can be easily adjusted to the required slurry flow rate without having to maintain a particularly efficient speed range as with a combustion engine, the flow rate of the second hydraulic pump can be very easily adjusted to the required slurry flow rate. The joint drive of both hydraulic pumps automatically ensures that the correct ratio of the flow rates of both hydraulic pumps is always achieved. Alternatively, the first and second hydraulic pumps can advantageously also be driven by separate drive motors. This makes it possible to easily adjust the flow rate of the second and first hydraulic pumps to the respective flow rate of the two-cylinder slurry pump. In a particularly advantageous embodiment, the second hydraulic pump is connected to the drive motor that drives the second hydraulic pump.The drive motor is arranged spatially close to the high-viscosity switching valve, and the at least one first hydraulic pump and the second hydraulic pump are each assigned their own hydraulic oil tank. The spatially close arrangement of the second hydraulic pump with the drive motor at the high-viscosity switching valve in conjunction with separate hydraulic tanks reduces hydraulic power losses and, in particular, minimizes the length of the hydraulic suction hoses to a centrally located hydraulic tank, which are difficult to accommodate and complex to install. Preferably, the drive motor driving the second hydraulic pump drives another hydraulic pump, which is intended to feed a hydraulic oil cooling and / or filter circuit. This additional hydraulic pump for feeding the hydraulic oil cooling and / or filter circuit ensures a constant hydraulic oil flow through the hydraulic oil cooling and / or filter circuit.which is advantageous, especially because a hydraulic oil filter, in particular, reacts sensitively to a pulsating oil flow, as naturally occurs in the drive circuit of the hydraulic switching accumulator. In an advantageous embodiment, the geometric delivery volume of the second hydraulic pump is variable, and it has a leakage oil connection, via which leakage oil can be fed to the hydraulic oil cooling and / or filter circuit. In particular, if the second hydraulic pump is assigned its own hydraulic tank, this measure allows the usually particularly hot leakage oil to be very easily used to cool the entire tank volume. Preferably, an agitator in a feed hopper mixes the thick material filled into the feed hopper, wherein the speed of the agitator is adjustable depending on the set thick material delivery rate. Furthermore, the present invention relates to a method for operating aTwo-cylinder high-viscosity pump, wherein the two-cylinder high-viscosity pump has at least one switching hydraulic cylinder fed from a switching hydraulic accumulator for driving a high-viscosity switching valve, which is provided for alternately connecting two delivery cylinders of the two-cylinder high-viscosity pump to a high-viscosity delivery line. According to the invention, in particular, a charging speed with which the switching hydraulic accumulator is charged with hydraulic oil between the switching operations of the high-viscosity switching valve is adjustable depending on a predetermined high-viscosity delivery rate. Due to the adaptability of the charging speed, in particular, the maximum power consumption for charging the switching hydraulic accumulator at a reduced high-viscosity delivery rate can be reduced by better distributing the power consumption over time, thereby freeing up drive power for driving the delivery cylinders. Further features, details, and advantages of theThe invention will become apparent from the following description and from the drawings, which show exemplary embodiments of the invention. Corresponding objects or elements are provided with the same reference numerals in all figures. They show: Figure 1 View of a two-cylinder piston pump according to the invention Figure 2 Drive diagram of a truck-mounted concrete pump according to the prior art Figure 3 Drive diagram according to the invention in a first embodiment Figure 4 Drive diagram according to the invention in a second embodiment Figure 5 Drive diagram according to the invention in a third embodiment Figure 6 Drive diagram according to the invention in a fourth embodiment Figure 7 Drive diagram according to the invention in a fifth embodiment Figure 8 Detailed view of a hydraulic drive unit according to the invention in a first variant Figure 9 Detailed view of a hydraulic drive unit according to the invention in a second variant Figure 10 Detailed viewa hydraulic drive unit according to the invention in a third variant Figure 1 shows a truck-mounted concrete pump 100 with a two-cylinder thick matter pump 111 according to the invention. The truck-mounted concrete pump 100 has a truck 102 driven by an internal combustion engine 103 and having a chassis 104, on the frame 105 of which a concrete pump structure 101 is arranged. The concrete pump structure 101 essentially has a concrete pump substructure 127 with a support 108 with hydraulically driven support cylinders 109 and foldable or extendable support beams 121, as well as a hydraulically driven two-cylinder thick matter pump 111 for conveying or pumping concrete. The concrete pump substructure 127 carries a feed hopper 116 for liquid fresh concrete at its rear end, in which an agitator 113 driven by a hydraulic motor stirs the fresh concrete, for example, poured in from a truck mixer. In the lower area of ​​the feed hopper 116A hydraulically driven high-density solids switching valve 112, for example in the form of a pipe switch (see Fig. 3), is arranged in an upwardly open housing 144. Instead of a pipe switch 112 (e.g., an S-pipe or a so-called rock slide valve), the high-density solids switching valve 112 could, for example, also be constructed from one or more rotary or flat slide valves. The concrete pump substructure 127 also contains the hydraulic pumps 115, 119, 117, and 118 (see Fig. 3) for driving the units 111, 107, 108, and 113 of the concrete pump superstructure 101. The concrete pump substructure 127 is connected via a turntable 106 to a placing boom 107, the individual boom segments 126 of which are connected to one another via articulated joints 125. The distribution boom 107, or each of the articulated joints 125, is actuated by means of hydraulic cylinders 110 or other suitable joint drives 110. The hydraulic pressure for driving the hydraulic cylinders 110 of the distribution boom 107 and the support 108 is supplied by theHydraulic pump 119 is provided. Figure 2 shows a drive diagram of a hybrid, i.e., diesel / electrically driven truck-mounted concrete pump 100 with a two-cylinder thick matter pump 111 according to the prior art. An internal combustion engine 103 drives the chassis 104 for driving operation via a transmission 134. The support 108, the distribution boom 107, the agitator 113, and the two-cylinder thick matter pump 111 are hydraulically driven by the hydraulic pumps 115, 119, 117, and 118 combined to form a hydraulic pump train 128, with an electric motor 122 driving the hydraulic pump train 128. The electric motor 122 draws its electrical energy from an electrical supply device 166. The electrical supply device 166 can, for example, draw electrical energy for the drive from a construction site power supply 133, an external accumulator 120 on a transporter 136 or a trailer, from an on-board accumulator 120 or from a generator 132.of the electric motor 122. The electric motor 122 typically rotates at a constant speed so that all units 107, 108, 111, 113 of the concrete pump assembly 101 can be supplied with pressurized oil and driven at all times via the hydraulic pumps 115, 119, 117, 118. Two hydraulic drive cylinders 147, driven in push-pull by the two first hydraulic pumps 115, are provided for driving two delivery pistons 149, each of which runs in one of two delivery cylinders 148 of the two-cylinder thick matter pump 111, wherein the thick matter delivery rate can be adjusted by adapting the delivery capacity of the at least one first hydraulic pump 115. The delivery capacity of the hydraulic drive cylinders 147 and thus the thick matter delivery rate is usually changed by adjusting the swivel angle of the hydraulic pumps 115 designed as axial piston pumps and the switching of the delivery cylinders is carried out via the switching device 163. The hydraulic pump 117, thecan also be referred to as a storage charging pump, always charges the switching hydraulic accumulator 146 for switching the thick matter switching valve 112 so quickly that, even with the maximum set thick matter delivery rate, the switching hydraulic accumulator 146 is filled at the switching time of the thick matter switching valve 112. Figure 3 shows a drive diagram of a two-cylinder thick matter pump 111 according to the invention in a first embodiment. The structure of the two-cylinder thick matter pump 111 with regard to the arrangement of the hydraulic drive cylinders 147, the delivery pistons 149, the delivery cylinders 148, and the thick matter switching valve 112 corresponds to the structure shown in Figure 2. The two-cylinder thick matter pump 111 has at least one, in this case two first hydraulic pumps 115, two hydraulic drive cylinders 147 driven in push-pull by the two first hydraulic pumps 115, which are provided for driving two delivery pistons 149, each of which is arranged in one of twoDelivery cylinders 148 of the two-cylinder thick matter pump run, wherein the thick matter delivery rate can be adjusted by adjusting the delivery capacity of the two first hydraulic pumps 115. The two-cylinder thick matter pump 111 also has a second hydraulic pump 117 and a switchover hydraulic accumulator 146, wherein the second hydraulic pump 117 is provided to charge the switchover hydraulic accumulator 146. Furthermore, the two-cylinder thick matter pump 111 has a switchover hydraulic cylinder 145 fed from the switchover hydraulic accumulator 146 and a thick matter switchover valve 112 driven by the at least one switchover hydraulic cylinder 145, which is provided for alternately connecting the two delivery cylinders 148 to a thick matter delivery line 164. The delivery capacity of the second hydraulic pump 117 can be adjusted depending on the set thick matter delivery rate. That is, the loading speed with which the switching hydraulic accumulator 146 switches between theThe thick matter switching valve 112 is loaded with hydraulic oil, is adjusted depending on a predetermined thick matter delivery rate. The thick matter delivery rate or the stroke rate of the hydraulic drive cylinders 147, which ultimately determines the thick matter delivery rate, is specified by an operator, for example, on an input unit 143, for example in the form of a remote control 143, and passed on to the control device 142. The control device 142 adjusts the swivel angles of the first hydraulic pumps 115, which are designed, for example, as axial piston pumps with swivel plates, via an output unit and the control line 141, such that the desired thick matter delivery rate or stroke rate of the two-cylinder thick matter pump 100 is achieved. In addition, the delivery capacity of the second hydraulic pump 117, which loads the switching hydraulic cylinder 146, is also adjusted depending on the set thick matter delivery rate, in thatsecond hydraulic pump 117, the delivery capacity of which is adjusted accordingly, for example, by adjusting the geometric delivery volume, for example, by adjusting the swivel angle of the hydraulic pump 117, if the latter is designed as an axial piston pump 117 with a swivel plate. The control device 142 and the second hydraulic pump 117 are connected to one another via the control line 135. This means that the control device 142 is configured to adjust the delivery capacity of the at least one first hydraulic pump 115 and the delivery capacity of the second hydraulic pump 117 in accordance with the set thick matter delivery rate. In the exemplary embodiment according to Figure 3, the hydraulic pumps 115, 119, 117, 118 are combined to form a hydraulic pump train 128 and are jointly driven by an electric motor M1. However, the hydraulic pump train 128 could also be driven by an internal combustion engine 103, for example, the drive system of the truck 102.Hydraulic oil is pumped from the second hydraulic pump 117 via a check valve 151 into the switching hydraulic accumulator 146, thereby charging it. At the time when the delivery pistons 149 each reach their end position in the delivery cylinders 148, the directional control valve 150, which controls the switching hydraulic cylinder 145, is switched, causing the high-viscosity switching valve 112 in its housing 144 to switch abruptly and connect the other delivery cylinder 148 to the high-viscosity delivery line 164 for the delivery of high-viscosity material. At the same time, the other delivery cylinder 148 is opened to the interior of the housing 144 so that it can suck in high-viscosity material or concrete from the housing 144. The delivery pistons 149 then move again in the opposite direction in the delivery cylinders 148, while the switching hydraulic accumulator 146 is charged in such a way that it is immediately before the next switching process of theThick matter switching valve 112 is completely filled, i.e. the switching hydraulic accumulator 146 is filled to such an extent that the filling volume and the filling pressure are sufficient to switch the switching hydraulic cylinder(s) 145 and thus the thick matter switching valve 112. It should be noted that even during the switching process the second hydraulic pump 117, which continues to run, provides hydraulic pressure, in addition to the hydraulic pressure of the switching hydraulic accumulator 145, for switching the thick matter switching valve 112. A pressure relief valve 152 ensures that any excess pressure in the switching hydraulic accumulator 146 is diverted into the hydraulic oil tank 153. This could occur, for example, if the thick matter switching valve 112 is stuck. In this exemplary embodiment, all hydraulic pumps 115, 117, 118, 119 draw hydraulic oil from the shared hydraulic oil tank 153. In the second embodiment according to Figure 4, the hydraulic pump train128 of a truck-mounted concrete pump 100 is divided into two sub-lines 128a and 128b, each driven separately by electric motors M1 and M2. The electric motor M2, connected to the DC link 130, which has, for example, a constant DC voltage of 600 volts, via the inverter 160a, drives the placing boom 107 or the support 108 via the hydraulic pump 119 and the agitator 113 via the hydraulic pump 118. For this purpose, the electric motor M2 is operated continuously at a constant speed, for example, as long as the hydraulic consumers 107, 108, 113 are in operation. The speed of the electric motor M2 could also be controlled via the inverter 160a. An optional accumulator 120 and an inverter 158 are also connected to the DC link 130. Instead of or in addition to the accumulator 120, a fuel cell for generating electrical energy, a supercapacitor or similarElectrical equipment may be provided. The inverter 158 is, for example, an on-board charger (OBC) that draws the alternating current from the construction site power supply 133 via one or more power connectors 159 and converts it into direct current for the DC link 130. The accumulator 120 can, on the one hand, be charged via the DC link 130, and, on the other hand, provide direct current for driving the electric motors M1 and M2 in order to operate them for a limited time when the construction site power supply 133 is not available. Furthermore, the accumulator 120 can absorb power peaks that could overload the construction site power supply 133 if the construction site power supply 133 is present and connected. The two first hydraulic pumps 115 for driving the hydraulic drive cylinders 147 of the two-cylinder thick matter pump 111 and the second hydraulic pump 117 for charging the switching hydraulic accumulator 146 together form theHydraulic pump train 128a and are driven by the common drive motor M1, in this case an electric motor M1, whereby the delivery capacity of the two first hydraulic pumps 115 for the hydraulic drive cylinders 147 and the delivery capacity of the second hydraulic pump 117 for charging the switchable hydraulic accumulator 146 can be adjusted by adjusting the speed of the drive motor M1. The speed of the electric motor M1 is controlled, for example, via an inverter 160b. The inverter 160b draws the power for the drive motor M1 from the DC intermediate circuit 130. The inverter 160b is also connected to the control device 142 via the control line 135, which adjusts the speed of the drive motor M1 via the inverter 160b based on the thick matter delivery rate set on the input unit 143. The delivery capacity of the second hydraulic pump 117 is also in the embodiment of Figure 4 dependent on the set thick matter delivery rateadapted, wherein the delivery capacity of the at least one first hydraulic pump 115 and the delivery capacity of the second hydraulic pump 117 can be adjusted by adjusting the speed of the drive motor M1. The embodiment according to Figure 5 shows a drive diagram in a third embodiment with a hybrid-driven truck-mounted concrete pump 100, i.e., the concrete pump structure 101 of the truck-mounted concrete pump 100 can be driven either by several electric motors M1 / G, M2, M3 or by the combustion engine 103 of the truck 102, or a combination thereof. The electric motor M1 / G, which in this embodiment, for example, drives the two first hydraulic pumps 115 for driving the hydraulic drive cylinders 147 and the hydraulic pump 119 for driving the distribution boom 107 and the support 108, additionally functions as a power generator in this embodiment. This means that the shaft of the motor / generator M1 / G can be connected to the hydraulic drive cylinder 147 via the decoupling device 165.For example, a switchable clutch or a freewheel can be mechanically coupled to the power take-off 123 or the power take-off gear 124 of the internal combustion engine 103, so that the hydraulic pumps 115 and 119 are driven via the power take-off 123 of the internal combustion engine 103, and the electric motor M1 / G generates electrical current, which is fed to the DC link 130 via the inverter 160a, for example to charge the accumulator 120 and / or to drive the electric motors M2 and M3 via their inverters 160b and 160c. Thus, in this exemplary embodiment, the concrete pump structure 101 can be driven with the aid of the internal combustion engine 103 even if the capacity of the accumulator 120 is insufficient and / or a construction site power supply 133 is not available. In this embodiment, the electric motor M3 directly drives the agitator 113. This has the advantage that hydraulic losses due to aHydraulic circuit with hydraulic pump and hydraulic motor can be avoided. Furthermore, through the independent operation of the agitator 113 via the electric motor M3, the speed of the agitator 113 can be adapted to the flow rate of the two-cylinder piston pump 111, whereby the drive energy for the agitator 113 is also reduced with a reduced flow rate. The principle of direct drive by an electric motor can also be applied to other units of the concrete pump structure 101 that do not necessarily have to be hydraulically driven, for example, a high-pressure cleaner. For the hydraulic control of the switchover hydraulic cylinder 145, a separate hydraulic drive unit 161 is provided in the embodiment according to Figure 5, which comprises, for example, the electric motor M2, the second hydraulic pump 117, a hydraulic oil cooling and / or filter circuit 137 with a hydraulic oil filter 155 and a hydraulic oil cooler 156, and a hydraulic oil tank 154. These elementsthus form a separate, self-contained hydraulic drive unit 161, which can be positioned at a suitable location, i.e., for example, as close as possible to the hydraulic consumer, in this case, the high-viscosity switching valve 112 with the switching hydraulic cylinder 145. In this exemplary embodiment, the electric motor M2 of the hydraulic drive unit 161, in addition to the second hydraulic pump 117, which charges the switching hydraulic accumulator 146, also drives a hydraulic pump 157, which continuously pumps hydraulic oil from the hydraulic oil tank 154 to the hydraulic oil filter 155 and hydraulic oil cooler 156 in order to filter and cool the hydraulic oil of the hydraulic drive unit 161. The second hydraulic pump 117 and the hydraulic pump 157 can, for example, be combined as a tandem pump. In this exemplary embodiment, the delivery capacity of the second hydraulic pump 117 is adjusted by adjusting the geometric delivery volume of the second hydraulic pump.117, as already described in connection with Figure 3 via the control line 135. In order to be able to more accurately determine the slurry flow rate delivered by the hydraulic drive cylinders 147 and, based on this, to optimally adjust the flow rate of the second hydraulic pump 117, the hydraulic oil flow rate to the hydraulic drive cylinders 147 is measured at the output of the first hydraulic pump 115 and signaled via the flow measurement signal line 131 to the control device 142, which, based on this, sets the optimal flow rate for the second hydraulic pump 117, so that the switching hydraulic accumulator 146 is completely filled immediately before a switching operation of the slurry switching valve 112. Because in the embodiment according to Figure 5 the essential hydraulic pumps are designed as variable displacement pumps, the electric motors M1 / G; M2 and M3 can run at constant speeds. The speeds of the motors M1 / G; M2 and M3 could, however, also be determined by theThe fourth exemplary embodiment shown in Figure 6 differs from the exemplary embodiment according to Figure 5 in particular in that the delivery capacity of the second hydraulic pump 117 is adjusted via the speed of the electric motor M2. This means that a control line 135 leads from the control device 142 to the inverter 160b for adjusting the speed of the electric motor M2. This has the advantage, for example, that with a reduced delivery capacity, the hydraulic pump 157 also drives the hydraulic oil cooling and / or filter circuit 137 with lower power, thereby reducing hydraulic losses. The fifth exemplary embodiment in Figure 7 shows a drive diagram of a truck-mounted concrete pump 100 with a two-cylinder thick matter pump 111 according to the invention, in which both the truck chassis and the concrete pump structure 101 are fully electric.This means that an electric drive motor MF is also provided for the travel drive of the truck-mounted concrete pump 100. The electric motor M1 drives the two first hydraulic pumps 115 for driving the hydraulic drive cylinders 147 and the hydraulic pump 119 for driving the placing boom 107 and the support 108. The second hydraulic pump 117, driven by the electric motor M2, charges the switchable hydraulic accumulator 146, wherein the delivery capacity of the second hydraulic pump 117 is adjusted depending on the set thick material delivery rate by adjusting the drive speed, for example, by the inverter 160b controlled by the control device 142. In the illustration in Figure 7, the accumulator 120 supplies both the travel drive motor MF and the electric motors M1, M2, M3 with electrical energy, whereby during concrete conveyance on the construction site, the mains connection plug(s) 159 are primarily used to supply the electric motorsM1, M2, M3 are provided with electrical power. In this case, the accumulator 120 serves, for example, to provide additional electrical power to the construction site power supply 133 during power consumption peaks of the concrete pump assembly 101, for example, when the two-cylinder thick matter pump 111 is delivering a high volume of thick matter. On the other hand, the construction site power supply 133 can be used to charge the accumulator 120 when the electrical power consumption of the concrete pump assembly 101 is low, for example, during delivery breaks. The accumulator 120 can also be a drive battery assigned to the truck chassis 104. The concrete pump assembly 101 can also have a separate accumulator 120 or be fully supplied with electrical power from one or more construction site power supplies 133 via the external power connector(s) 159, if a drive battery of the truck chassis 104 is not available for the electricalOperation of the concrete pump assembly 101 can be used. In the embodiments of Figures 4 to 7, the inverters 158, 160a, 160b, 160c are shown as separate modules that are connected to one another via the DC link 130. In principle, the inverters 158, 160a, 160b, 160c can also be combined to form an electrical supply device 166, i.e., practically as shown in Figure 2. Because the inverters 158, 160a, 160b, 160c generally need to be cooled during operation, a common air or liquid cooling system can then be provided for the inverters 158, 160a, 160b, 160c, for example. Figure 8 shows a variant of the hydraulic drive unit 161 in which the geometric delivery volume of the second hydraulic pump 117 is variable and it has a leakage oil connection via which leakage oil can be fed to the hydraulic oil cooling and / or filter circuit 137. In particular, hydraulic pumps with a variable geometricDisplacement volumes, e.g., axial piston pumps with a swivel disk, usually have such a leakage oil connection 162, so that the hydraulic oil escaping via the leakage oil connection 162 is fed to the hydraulic oil cooling and / or filter circuit 137 and cooled and, if necessary, also filtered via the hydraulic oil filter 155, which is located upstream of the hydraulic oil cooler 156. Figure 9 shows a further alternative embodiment of a hydraulic drive unit 161, with which the thick matter changeover valve 112 and the agitator 113 are driven. The hydraulic drive unit 161 has two hydraulic pumps 117 and 118, which are provided for the pressure oil supply to the two working devices 112, 113 in hydraulic working circuits and which suck hydraulic oil from a hydraulic oil tank 154. For example, the hydraulic pump 117 drives the thick matter switching valve 112 and the hydraulic pump 118 drives the agitator 113. Both the thick matter switching valve 112 and theAgitators 113 are arranged in or on the feed hopper 116 of the concrete pump 100, respectively, so the hydraulic drive unit 161 is located spatially close to the working devices 112, 113. The hydraulic working circuit of the agitator drive, in which a hydraulic motor drives the agitator shaft, is also used here to cool the hydraulic oil of the hydraulic drive unit 161. The hydraulic oil is supplied from the hydraulic pump 118 to the agitator 113, or to the hydraulic motor that drives the agitator 113. From the agitator 113, the return line leads through the hydraulic oil filter 155 and the hydraulic oil cooler 156 back to the hydraulic oil tank 154. This simultaneously turns the hydraulic pump 118 into a cooling circuit pump and the return line simultaneously fulfils the function of the hydraulic oil cooling and / or filter circuit 137. In addition, in this embodiment, the hydraulic oil cooled by the hydraulic oil cooler 156 is used for liquid cooling of theElectric motor M2 is used in that the hydraulic oil is fed via a line to the electric motor M2, then flows through the motor housing of the electric motor M2, cooling it in the process, and is then fed via another line to the hydraulic oil tank 154. Alternatively, in this exemplary embodiment, the hydraulic pumps 117 and 118 could be combined into one hydraulic pump, which drives both the thick matter switching valve 112 and the agitator 111 simultaneously. However, this requires a suitable hydraulic circuit for adjusting the hydraulic oil pressures for the two working units 112 and 113. In this variant, it is particularly advantageous that the common drive motor M2 of the agitator 113 and the switching hydraulic accumulator 146 allows the charging process of the switching hydraulic accumulator 146 to be adjusted to the delivery capacity of the second hydraulic pump 117 depending on the set thick matter delivery rate via the speed of the drive motor.M2, the speed of the agitator 113 is also adapted to the delivery rate. This means that by adjusting the delivery rate of the second hydraulic pump 117 depending on the set thick matter delivery rate, the speed of the agitator 113 is also automatically adapted to the thick matter delivery rate, which saves drive energy for the concrete pump 100, particularly when the set thick matter delivery rate is low. Figure 10 shows a variant of the hydraulic drive unit 161 in which the second hydraulic pump 117, whose delivery rate in this case is regulated via the drive speed of the electric motor M2, is switched to pressureless circulation when the necessary accumulator filling pressure is reached for switching the thick matter changeover valve 112, by the directional valve 138 opening the hydraulic oil cooling and / or filter circuit 137. The remaining time until the switching hydraulic accumulator 146 is emptied can thus be used for cooling and filteringof the hydraulic oil of the hydraulic drive unit. Once the pressure falls below a set hysteresis, the directional control valve 138 is closed again and the switching hydraulic accumulator 146 is refilled. The exemplary embodiments shown here relate to the hydraulic drive of the hydraulic drive cylinders 147 of the two-cylinder high-viscosity pump in a so-called open hydraulic circuit. The invention is also readily transferable to the hydraulic drive of the hydraulic drive cylinders 147 in a closed hydraulic circuit with so-called reversing pumps, in which the hydraulic switching of the high-viscosity switching valve 112 is possible in the same way as presented here.

[0002] List of reference symbols 100 Truck-mounted concrete pump 101 Concrete pump body 102 Truck 103 Truck combustion engine 104 Chassis 105 Truck frame 106 Turntable 107 Distributor boom 108 Support 109 Support cylinder 110 Articulated joint drive 111 Two-cylinder thick matter pump 112 Thick matter changeover valve 113 Agitator 115 First hydraulic pump for hydraulic drive cylinder 116 Feed hopper 117 Second hydraulic pump for changeover hydraulic accumulator 118 Hydraulic pump agitator 119 Hydraulic pump mast / support 120 Accumulator 121 Support beam 122 Electric motor (St.dT) 123 Power take-off (PTO) 124 Power take-off gearbox (NMV) 125 Articulated joint 126 Boom arm segments 127 Concrete pump substructure 128 Hydraulic pump line 130 DC link 131 Flow measurement signal line 132 Power generator (St.dT) 133 Construction site power supply 134 Travel drive gear 135 Control line for delivery capacity of second hydraulic pump 136 Transporter with electrical energy storage 137 Hydraulic oil cooling and / or filter circuit 138 Directional control valve 139 Power line 140 Hydraulic control line for cooling circuit 141 Control line for delivery rate 142 Control device 143 Input unit 144 Housing for high-viscosity switching valve 145 Switching hydraulic cylinder 146 Switching hydraulic accumulator 147 Hydraulic drive cylinder 148 Delivery cylinder 149 Delivery piston 150 Directional control valve 151 Check valve 152 Pressure relief valve 153 Hydraulic oil tank 154 Hydraulic oil tank - drive unit 155 Hydraulic oil filter 156 Hydraulic oil cooler 157 Cooling pump 158 Inverter 159 Mains connection 160 Inverter 161 Hydraulic drive unit 162 Leakage oil connection 163 Switching hydraulic drive cylinder 164 Thick matter conveying line 165 Decoupling device 166 Electrical supply device M; M1; M2; M3: Electric motors MG: Electric motor / generator - Patent claims -.

Claims

1. A two-cylinder slurry pump (111), in particular for a truck-mounted concrete pump (100), comprising - at least one first hydraulic pump (115), - two hydraulic drive cylinders (147) driven in push-pull by the at least one first hydraulic pump (115), which are provided for driving two delivery pistons (149), each running in one of two delivery cylinders (148) of the two-cylinder slurry pump (111), wherein a slurry delivery rate can be adjusted by adjusting the delivery capacity of the at least one first hydraulic pump (115), - a second hydraulic pump (117), - a switchover hydraulic accumulator (146), wherein the second hydraulic pump (117) is provided for charging the switchover hydraulic accumulator (146), - at least one switchover hydraulic cylinder (145) fed from the switchover hydraulic accumulator (146), - one of the at least one switchover hydraulic cylinder (145) driven thick matter switching valve (112),which is provided for the alternating connection of the two delivery cylinders (148) to a thick matter delivery line (164), characterized in that the delivery capacity of the second hydraulic pump (117) is adjustable depending on the set thick matter delivery rate.

2. Two-cylinder thick matter pump (111) according to claim 1, characterized in that the delivery capacity of the second hydraulic pump (117) is adjustable such that the switching hydraulic accumulator (146) is completely filled immediately before a switching operation of the thick matter switching valve (112).

3. Two-cylinder thick matter pump (111) according to claim 1 or 2, characterized by a control device (142) which is designed to control the delivery capacity of the at least one first hydraulic pump (115), and adjust the delivery rate of the second hydraulic pump (117) according to the set slurry delivery rate.

4. Two-cylinder slurry pump (111) according to one of claims 1 to 3, characterized in that the delivery rate of the second hydraulic pump (117) is adjustable by adjusting the geometric delivery volume of the second hydraulic pump (117).

5. Two-cylinder slurry pump (111) according to one of claims 1 to 3, characterized in that the delivery rate of the second hydraulic pump (117) is adjustable by adjusting the drive speed of the second hydraulic pump (117). 6.A two-cylinder slurry pump (111) according to one of claims 1 to 3, characterized by a common drive motor (M1) that drives the at least one first hydraulic pump (115) and the second hydraulic pump (117), wherein the delivery capacity of the at least one first hydraulic pump (115) and the delivery capacity of the second hydraulic pump (117) are adjustable by adjusting the speed of the drive motor (M1).

7. A two-cylinder slurry pump (111) according to one of claims 1 to 6, characterized in that the at least one first hydraulic pump (115) and the second hydraulic pump (117) are driven by separate drive motors (M1, M2).

8. A two-cylinder slurry pump (111) according to claim 7, characterized in that the drive motor (M2) driving the second hydraulic pump (117) is an electric motor.Two-cylinder thick matter pump (111) according to claim 7 or 8, characterized in that the second hydraulic pump (117) with the drive motor (M2) driving it is arranged spatially close to the thick matter switching valve (112) and the at least one first hydraulic pump (115) and the second hydraulic pump (117) are each assigned their own hydraulic oil tank (153, 154).

10. A two-cylinder slurry pump (111) according to one of claims 7 to 9, characterized in that the drive motor (M2) driving the second hydraulic pump (117) drives a further hydraulic pump (157) intended to feed a hydraulic oil cooling and / or filter circuit (137).

11. A two-cylinder slurry pump (111) according to one of claims 7 to 9, characterized in that the geometric delivery volume of the second hydraulic pump (117) is variable and it has a leakage oil connection (162) via which leakage oil can be supplied to the hydraulic oil cooling and / or filter circuit (137).

12. Two-cylinder slurry pump (111) according to one of the preceding claims, characterized in that an agitator (113) in a feed hopper (116) mixes the slurry filled into the feed hopper (116), wherein the speed of the agitator (113) is adjustable depending on the set slurry flow rate.Method for operating a two-cylinder thick matter pump (111), wherein the two-cylinder thick matter pump (111) has at least one switching hydraulic cylinder (145) fed from a switching hydraulic accumulator (146) for driving a thick matter switching valve (112) which is provided for alternately connecting two delivery cylinders (148) of the two-cylinder thick matter pump (111) to a thick matter delivery line (164), characterized in that a charging speed at which the switching hydraulic accumulator (146) is charged with hydraulic oil between the switching operations of the thick matter switching valve (112) is adapted as a function of a predetermined thick matter delivery quantity.

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