Device for controlling a kaplan-type hydraulic machine

Abstract

Kaplan machines comprise a runner having pivotable runner blades. The present invention relates to a device which enables regulation of the pitch angle of the runner blades. Furthermore, a Kaplan machine comprises an adjustable wicket gate. The present invention relates in particular to the combined regulation of the rotor and the wicket gate of the hydraulic machine. The device according to the invention is characterised by high efficiency and high long-term reliability.

Description

[0001] Device for controlling a hydraulic machine of the Kaplan type

[0002] The invention relates to a device for controlling a Kaplan-type hydraulic machine, also known as a Kaplan machine. Kaplan machines comprise an impeller with pivoting impeller blades. The present invention relates to a device by which the angle of attack of the impeller blades can be controlled. Furthermore, a Kaplan machine comprises an adjustable guide vane. The present invention particularly relates to the combined control of the impeller and guide vane of the hydraulic machine.

[0003] In a Kaplan machine, the energy required to adjust the impeller blades is conventionally provided in the form of pressure and flow rate by a hydraulic accumulator with a downstream control valve. In this open system, the accumulator pressure is throttled by opening the control valve until the required flow rate for the required cylinder movement is achieved. This technology allows both differential and double-threaded cylinders to be controlled without restrictions.

[0004] Other devices for controlling a hydraulic machine have become known from the prior art. DE 10 2017 106 693 B3 discloses such a device, which is also suitable in principle for controlling the impeller of a Kaplan machine. The disclosed device uses a variable-speed pump arrangement connected to a hydraulic cylinder via releasable check valves. However, various difficulties arise related to the fact that the hydraulic cylinder used to pivot the rotor blades is part of the rotating system of the hydraulic machine, while the rest of the device is part of the stationary system.To allow the hydraulic fluid (usually oil) used to operate the hydraulic cylinder to flow from the stationary system to the rotating system and back again, a rotary union is typically provided, which is called an oilhead in hydropower. Rotary unions generally have a certain amount of internal oil leakage, which is also required to cool and lubricate the bearings of the rotary union. Depending on the type, the pressure applied to the rotary union, and the prevailing oil temperature, the internal oil leakage can range between 0.5 and 200 l / min. To keep the impeller in position (the most common operating mode, approximately 90% of operating time), constant control is necessary to compensate for the drift of the hydraulic cylinder (caused by the rotary union leakage).

[0005] If the device disclosed in DE 10 2017 106 693 B3 is to be used to control the impeller blade position of a Kaplan machine, different difficulties arise depending on the type of pump used. If a gear pump is used for the pump arrangement, this is problematic because these are not approved for continuous operation at the low speeds required to hold the impeller in position. The resulting rapid pump wear rules out this option. If a piston pump is used for the pump arrangement, low speeds at high pressure can be operated without any problems in continuous operation. However, the following aspects lead to significantly increased losses in such a system. For permissible continuous operation, piston pumps must be supplied with flushing oil. In addition to the constant operation of an additional flushing pump, this also means additional constant losses in the system.In addition, during continuous pump operation, the pilot-operated check valves must also be permanently open. This would continuously drain the internal pump leakage of the piston pump from the reservoir as a further loss.

[0006] The object of the invention is to modify the device disclosed in DE 10 2017 106 693 B3 in such a way that it can be used to control the impeller of a Kaplan machine efficiently and reliably over a long period of time.

[0007] The object is achieved according to the invention by an embodiment according to the independent claim. Further advantageous embodiments of the present invention can be found in the subclaims. The invention is explained below with reference to figures. The figures show in detail:

[0008] Fig. 1 a: Device according to the invention in a first embodiment

[0009] Fig. 1 b: Device according to the invention in a second embodiment

[0010] Fig. 2: Device according to the invention in a further embodiment

[0011] Figure 1a shows a schematic diagram of a first embodiment of a device according to the invention for controlling a Kaplan-type hydraulic machine. The device serves to control the angle of attack of the impeller blades. The device comprises a collecting and compensating tank, designated 1, a first pump arrangement, designated 2, a second pump arrangement, designated 3, an accumulator, designated 5, and a hydraulic cylinder, designated 6. The hydraulic cylinder 6 actuates the adjustment mechanism for the impeller blades, which is not shown in Figure 1a, and is part of the rotating system. The hydraulic cylinder 6 can be designed as a double-action cylinder or as a differential cylinder.In a double-acting cylinder, the pressurised areas and volumes of the two cylinder chambers are the same size, whereas in a differential cylinder they are different. In a differential cylinder, a distinction is made between two sides of the cylinder. The side on which the rod is located is called the rod side and the other side is the piston side. The hydraulic cylinder is connected to the rest of the device by a rotary union, which is designated 7. Each of the two pump assemblies 2 and 3 comprises a variable-speed pump drive. The first pump assembly 2 is used to control the hydraulic cylinder 6 in a first operating mode, and the second pump assembly 3 is used to control the hydraulic cylinder 6 in a second operating mode. The first operating mode is characterized by the rapid movement of the impeller blades. This operating mode typically accounts for approximately 10% of the total operating time.The second operating mode is characterized by the impeller blades being held in a fixed position or moving very slowly. This second operating mode typically accounts for approximately 90% of the total operating time.

[0012] The device shown in Figure 1a is very similar to the device known from DE 10 2017 106 693 B3 in the arrangement provided for the first operating mode (i.e. with regard to the first pump arrangement 2). Here too, the first pump arrangement 2 comprises two pumps with a reversible pumping direction. In Figure 1a, the two pumps are arranged on a shaft which is driven by the variable-speed pump drive connected to the shaft. However, other structural designs are also possible, e.g. the pumps are driven by the pump drive via a gear unit. It is even conceivable for the pump drive to comprise a motor and a frequency converter for each of the two pumps. The further description refers to the embodiment shown in Figure 1a.In each case, a connection of a pump is connected to a control line of the hydraulic cylinder 6, so that in one direction of rotation of the shaft, one pump delivers hydraulic fluid toward the hydraulic cylinder 6 and the other pump receives hydraulic fluid from the hydraulic cylinder 6. In the other direction of rotation of the shaft, the situation is reversed. In contrast to the device from DE 10 2017 106 693 B3, in Figure 1a, the rotary union 7 is arranged between the hydraulic cylinder 6 and the connections of the first pump arrangement 2. The rotary union 7 merely carries out the transmission to the rotating system.

[0013] Like the device from DE 102017 106693 B3, the device shown in Figure 1a comprises two pilot-operated check valves, designated 4.1 and 4.3, and two pilot valves, designated 4.2 and 4.4. The right connection of the lower pump is connected to the right side of the hydraulic cylinder 6 via the pilot-operated check valve 4.3, and the left connection of the upper pump is connected to the left side of the hydraulic cylinder 6 via the pilot-operated check valve 4.1. The lines from the first pump assembly 2 to the rotary union 7, in which the pilot-operated check valves 4.1 and 4.3 are arranged, are referred to below as control lines. The remaining connections of the pumps are each directly connected to the collection and equalization tank 1. This meansIn one direction of shaft rotation, the lower pump pumps hydraulic fluid from the collection and equalization tank 1 into the right side of hydraulic cylinder 6, while the upper pump simultaneously pumps hydraulic fluid from the left side of hydraulic cylinder 6 into the collection and equalization tank 1. In the other direction of shaft rotation, the flow rates are reversed. In each case, it is assumed that the check valves 4.1 and 4.3 are unlocked (see below in the description of operating states).

[0014] In contrast to the device from DE 10 2017 106 693 B3, the rotary union 7 causes a permanent outflow of hydraulic fluid into the collection and compensation tank 1. The hydraulic fluid required for this comes (in both operating modes) from the collection and compensation tank 1 and the accumulator 5, which is connected to one of the control lines. A preferably adjustable throttle, designated 4.9, is arranged between the relevant control line and the accumulator 5. A pilot-operated check valve, designated 4.7, is arranged parallel to the throttle 4.9. Analogous to the check valves 4.1 and 4.3, the check valve 4.7 is controlled by a pilot valve, designated 4.8. In the first operating mode, the check valve 4.7 is opened, so that the throttle 4.9 is ineffective. In the second operating mode, the check valve 4.7 is closed, so that the throttle 4.9 is effective (see below in the description of the operating states).

[0015] The shaft of the first pump assembly 2 is driven by a variable-speed pump drive that can be operated in both directions. The pump drive typically comprises an electric servomotor powered by a frequency converter. The pump drive of the first pump assembly 2 is preferably suitable for 4Q operation.

[0016] The shaft of the second pump assembly 3 is also driven by a variable-speed pump drive, which can be operated in both directions. The pump drive typically comprises an electric servomotor powered by a frequency converter. The pump drive of the second pump assembly 3 is preferably suitable for 2Q operation.

[0017] The shaft of the second pump arrangement 3 is only connected to one pump. One connection of this pump is connected to the collection and equalization tank 1, and the other connection is connected to a control line. The line from the second pump arrangement 3 opens into the control line to which the accumulator 5 is not connected. The line from the second pump arrangement 3 to the relevant control line is referred to below as the pressure line. The opening of the pressure line into the relevant control line is also located between the associated pilot-operated check valve (Figure 1a - check valve 4.1) and the rotary union 7. A pilot-operated check valve, designated 4.13, is arranged in the pressure line. The check valve 4.13 is controlled by a pilot valve, designated 4.14.Optionally, the pressure line and the control line connected to it are connected to the collection and equalization tank 1 via a throttle and a 3 / 2-way valve. The throttle is designated 4.12, and the 3 / 2-way valve is designated 4.11. When the 3 / 2-way valve 4.11 is switched, a throttled bypass to the equalization tank (1) is opened (see below in the description of operating states).

[0018] The pumps of the first pump arrangement 2 can be designed as gear pumps or as piston pumps without flushing. Gear pumps allow easy adaptation to a hydraulic cylinder designed as a differential cylinder. In this case, the pumps of the first pump arrangement 2 are preferably designed as double gear pumps. Piston pumps are suitable for hydraulic cylinders designed as double-gear cylinders. The pump of the second pump arrangement 3 can be designed as a piston pump with or without flushing. If the pump is flushed, the bypass line with throttle 4.12 and 3 / 2-way valve 4.11 can be omitted. If the pump of the second pump arrangement 3 is designed as a piston pump without flushing or as a simple gear pump, the bypass line with throttle 4.12 and 3 / 2-way valve 4.11 is required to avoid critically low speeds that could permanently damage the pump of the second pump arrangement 3.

[0019] If the pumps used have designated pressure and suction connections, the pressure connections are preferably always connected to the hydraulic cylinder 6 and the suction connections to the collection and equalization tank 1.

[0020] Optionally, the device according to the invention can comprise two pressure relief valves connected to the control lines. In Figure 1a, the optional pressure relief valves are designated 4.5 and 4.6. Furthermore, a flow sensor can optionally be arranged in the line from the accumulator 5 to the respective control line. In Figure 1a, such an optional flow sensor is designated 4.10. This can be used to monitor the amount of hydraulic fluid withdrawn from the accumulator.

[0021] Optionally, the device according to the invention can comprise a so-called bypass unit, which represents an alternative storage charging option (see below in the description of the operating states). Such a bypass unit is shown in Figure 1a and designated by 8. The bypass unit 8 is connected to the collection and equalization tank 1 and the storage tank 5 and comprises a third pump arrangement, designated by 8.1. The third pump arrangement 8.1 comprises a drive and a pump connected to the drive. In a preferred embodiment, the third pump arrangement 8.1 comprises a constantly rotating AC motor with a flanged gear pump. However, the third pump arrangement 8.1 can also be designed differently. Optionally, the bypass unit can comprise a filter unit and / or a cooling unit. In Figure 1a, these units are indicated by rectangles and designated by 8.2 and 8.3.The bypass unit 8 comprises an electrically controlled changeover valve (not shown). If the changeover valve is closed, the accumulator 5 is charged via the pump of the bypass unit 8. If the changeover valve is open, the bypass unit 8 filters and / or cools the hydraulic fluid in the collection and equalization tank 1 in unpressurized circulation (if the bypass unit 8 comprises the corresponding units). If the hydraulic cylinder 6 is designed as a differential cylinder, the accumulator 5 is preferably connected to the control line belonging to the rod side of the hydraulic cylinder 6. The inventors have recognized that in this case the expected leakage at the rotary union 7 is lower. If a differential cylinder is used, it is advantageous if the flow ratio of the two pumps of the second pump unit 3 is adapted to the area ratio of the cylinder.This adjustment does not have to be perfect, as the remaining difference is compensated by storage 5. However, this exchange volume only comes into play in the second operating mode.

[0022] The embodiment of a device according to the invention shown in Figure 1a is suitable for hydraulic cylinders of all types, i.e., both differential and double-action cylinders. Figure 1b shows an embodiment that is suitable and optimized for double-action cylinders only. Since the embodiments shown in Figures 1a and 1b largely correspond, only the differences between the embodiment shown in Figure 1b and the embodiment shown in Figure 1a will be described below.

[0023] In the embodiment shown in Figure 1b, the first pump assembly 2 comprises only one pump with equal flow rates in both directions of rotation. This pump is preferably designed as a 4Q piston pump. The two pump connections are connected to the control lines. The connections from the first pump assembly 2 to the collection and equalization tank 1 shown in Figure 1a are omitted.

[0024] In the embodiment according to Figure 1 b, the bypass unit 8 is no longer optional, since the reservoir can no longer be filled with the aid of the pump arrangement 2. This can then only be done via the bypass unit, which on the other hand offers the advantage that the reservoir can be filled without interrupting control operation (see also below). Optionally, the pump can comprise a flushing oil connection which is connected to the bypass unit 8. A throttle is arranged in the corresponding connecting line, with which the flow rate of flushing oil can be adjusted. Furthermore, in this optional configuration, a pre-stressed check valve is arranged in the return line from the bypass unit 8 to the collection and equalization tank 1. When the third pump arrangement 8.1 operates in pressureless circulation (i.e. with the changeover valve open), part of the circulating volume flows through the pump of the first pump arrangement 2 in order to cool it.This optional arrangement can protect the pump of the first pump arrangement 2 from possible wear.

[0025] It should be noted that the embodiments of the device according to the invention shown in Figures 1a and 1b, in contrast to the device from DE 10 2017 106 693 B3, do not include the elements for an emergency closure disclosed therein. This is because, in a Kaplan-type hydraulic machine, the emergency closure is not realized (or only in a subordinate manner) via the position of the impeller blades, but (primarily) by closing the guide vane. An embodiment of the device according to the invention with emergency closure functionality is described further below.

[0026] The different operating states of the devices shown in Figures 1 a and 1 b are described below.

[0027] The first operating mode concerns the control of hydraulic cylinder 6. This operating mode is divided, as already described above, into a first operating mode (rapid change of the position of the impeller blades) and a second operating mode (holding the position of the impeller blades or moving them very slowly).

[0028] In the first operating mode, the second pump assembly 3 is deactivated and the first pump assembly 2 is activated simultaneously. Both check valves 4.1 and 4.3 in the control lines, as well as the check valve to the accumulator 4.7, are opened, and the check valve 4.13 in the pressure line of the second pump assembly 3 is closed (if open). Analogous to the device described in DE 10 2017 106 693 B3, the speed-controlled drive of the first pump assembly 2 can now control the hydraulic cylinder 6 in both directions in an efficient closed circuit in 4Q operation. Only the energy required to overcome the load and friction at the specified speed needs to be applied.

[0029] In the embodiment according to Figure 1 a, any required exchange volume can either be sucked in from the collection and equalization tank 1 or pressed into the accumulator 5 via the check valve 4.7 unlocked in the first operating mode.

[0030] The open connection to the accumulator 5 ensures in every embodiment that the pressure in the control line on the accumulator side does not collapse, even during rapid movements. Firstly, this ensures that the drive of the first pump arrangement 2 runs under energetically optimal pressure conditions and secondly, it avoids a possible critical pressure of < 5 bar, which could lead to cavitation of the pump. The drive of the first pump arrangement 2 is designed so that the maximum adjustment speed is achieved. Here, too, no control energy comes from the accumulator 5. The stored hydraulic fluid serves only to lubricate and cool the rotary union 7. In the embodiment according to Figure 1 b, the internal losses of the pump of the first pump arrangement are also compensated by the accumulator 5.

[0031] In the second operating mode, the position of the hydraulic cylinder 6 is maintained or very slowly regulated solely by the second pump assembly 3. The first pump assembly 2 is inactive. The pilot-operated check valves 4.1 and 4.3 in the control lines are in the closed position. This means that the pilot valves 4.2 and 4.4 are in the spring-loaded, de-energized position. The accumulator 5 is connected to a port of the rotary union 7 via the (preferably adjustable) throttle 4.9 and the pilot-operated check valve 4.7 connected in parallel. It primarily serves as a supply reservoir for hydraulic fluid as a lubricant and coolant for one half of the rotary union 7.

[0032] In the second operating mode, the pilot-operated check valve 4.7 to the accumulator 5 is in the closed position. This means that only the throttle 4.9 is active, reducing the cross-section and thus the resulting pressure at the rotary union 7. This also reduces the resulting leakage of the rotary union 7 on the accumulator connection side. The pressure on the accumulator side, in conjunction with the leakage on the non-accumulator side, causes the hydraulic cylinder 6 to move slowly towards the non-accumulator side. In order to hold the hydraulic cylinder 6 in position, the second pump arrangement 3 must work against this movement. The second pump arrangement 3 must therefore compensate for the leakage of the rotary union 7 on the non-accumulator side. Since the second pump arrangement 3 is a speed-controlled drive, only the energy corresponding to the actual load and the actually required volume flow needs to be applied.The second pump arrangement 3 must be designed large enough to compensate for leaks and allow small control movements to be carried out. In order to always guarantee the minimum speed of the second pump arrangement 2, which depends on the applied pressure, the 3 / 2-way valve 4.11 with upstream throttle 4.12 is integrated in the pressure line of the second pump arrangement 3 (unless it is a flushed piston pump). If the solenoid valve is switched, a throttled bypass to the collection and equalization tank 1 is opened. The resulting leakage must also be compensated by the second pump arrangement 3, which results in an increase in the delivery volume and thus an increase in the speed. This avoids critically low speeds that could damage the pump of the second pump arrangement 3 in the long term.Critical low speeds can occur with reduced leakage from the rotary union 7, which in turn can be caused by low ambient temperatures, since the viscosity of the hydraulic fluid also decreases at low temperatures. Such bypass operation of the second pump arrangement 3 can also be used to heat the hydraulic fluid. Smaller control movements in both directions can also be performed with the second pump arrangement 3.

[0033] • If the hydraulic cylinder 6 is to be moved towards the storage side, the associated pump must build up pressure and pump to the storage side.

[0034] • If the hydraulic cylinder 6 is to be moved to the non-accumulator side, the associated pump must reduce pressure and drain the hydraulic fluid into the collection and equalization tank 1. For this purpose, the pilot-operated check valve 4.13 in the pressure line of the auxiliary drive is opened via the associated solenoid valve 4.14.

[0035] If the flow rate of hydraulic fluid required for a required control movement exceeds the maximum flow rate that can be achieved by the second pump arrangement 3, a change from the second operating mode to the first operating mode takes place.

[0036] The accumulator pressure should be at least as high as the maximum pressure required to move the hydraulic cylinder 6 against the hydraulic load and against friction. Otherwise, when a control movement is required, the accumulator may first charge up to the specified maximum pressure before any cylinder movement can take place. In many cases, this will correspond to the conventional minimum system pressure PR. Typical values ​​for PR in the high pressure range are 80 or 110 bar. Since the accumulator only has to hold hydraulic fluid for lubrication and cooling and some exchange volume, but is not required to control the hydraulic cylinder, the accumulator volume only depends on the selected accumulator charging interval and the exchange volume to be maintained. The shorter the accumulator charging interval, the lower the accumulator volume and vice versa.For the upper nominal storage pressure, the maximum pressure according to IEC 61362 can be taken for pomax: pomax = 160 bar.

[0037] The accumulator charging function can be implemented in the embodiment according to Figure 1 a in two alternative ways, which can also be combined. Analogous to the device described in DE 10 2017 106 693 B3, the accumulator 5 can be charged via the drive of the first pump arrangement 2. For this purpose, the drive of the second pump arrangement 3 is deactivated and both check valves 4.1 and 4.3 in the control lines are blocked. If the drive of the first pump arrangement 2 now pumps into the accumulator side, the accumulator 5 is charged. Due to the leaks in the rotary union and the inactive control from the drive of the second pump arrangement 3 and the drive of the first pump arrangement 2, the hydraulic cylinder 6 will slowly drift in this situation. Since the provision of hydraulic fluid for lubrication and cooling must be given higher priority than the control quality in this case, this behavior is acceptable for the short period of accumulator charging.

[0038] Alternatively, a bypass unit 8 can be provided for charging the storage tank. Its functionality, with optional filtering and cooling functionality, has already been described above. Providing a bypass unit 8 for charging the storage tank offers the advantage that the storage tank charging function can be implemented redundantly. If charging the storage tank with the bypass unit 8 does not work, the drive of the first pump assembly 2 can be used for charging the storage tank.

[0039] In the embodiment according to Figure 1 b, only the bypass unit 8 is available for storage charging.

[0040] In any case, the lower switching point for the accumulator charge pomin can be selected very low, since neither hydraulic fluid is required for control in normal operation nor hydraulic fluid for an emergency shutdown function.

[0041] The inventors designed the device according to the invention for a selected Kaplan-type hydraulic machine. Oil is used as the hydraulic fluid. In the selected example, a reservoir with a usable capacity of 40 liters of oil between pR=110 bar and pomax=160 bar resulted. The lower switching point pomin was set to 120 bar. Thus, the volume between PR and pomin is 10 liters. With a realistic leakage oil flow of a standard high-pressure rotary union of 2 l / min, the reservoir must be recharged after 15 minutes. If the reservoir charging fails, the remaining 10 liters provide lubricating and cooling oil for another 5 minutes to safely shut down the machine.

[0042] In a Kaplan-type hydraulic machine, in addition to the position of the impeller blades, the position of the vanes of the guide vanes is also controlled. In principle, the two control units can be independent of one another, with the control being controlled by a common control device. However, the device according to the invention shown in Figure 1 can be particularly advantageously combined with a device as described in DE 10 2017 106 693 B3. Such a combination is shown in Figure 2. For better clarity, various elements of the device shown in Figure 1 are combined to form a so-called impeller unit. The relevant elements are framed in Figure 1 by the dotted line, designated 4.

[0043] Figure 2 shows a device according to the invention for controlling a Kaplan-type hydraulic machine, wherein the device can be used to control both the position of the impeller blades and the position of the vanes of the guide vane. To control the position of the impeller blades, the device comprises an impeller unit, which is again designated by 4. The impeller unit can be constructed as shown in Figure 1a or Figure 1b. To control the position of the vanes of the guide vane, the device comprises a so-called guide vane unit. The relevant elements are framed in Figure 2 by the dotted line, which is designated by 9. The guide vane unit 9 shown in Figure 2 represents a special embodiment. However, the guide vane unit 9 could also be constructed differently.For the various possible embodiments of the guide vane unit 9, reference is made to DE 102017 106 693 B3, the description of which is intended to be part of this document for the purpose of explaining the structure and functioning of a guide vane unit 9 in more detail. For this reason, the designation of the elements of the guide vane unit 9 in Figure 2 has been adapted to the designations in DE 10 2017 106 693 B3. "9." has been placed in front of each element merely to indicate that the elements in question belong to the guide vane unit 9. It should therefore only be mentioned here in addition that the impeller unit 4 and the guide vane unit 9 use a common collecting and equalizing tank 1, that the accumulator 9.5 of the guide vane unit 9 is designed as a piston accumulator, and that the guide vane unit 9 shown in Figure 2 does not have the optional quick-closing functionality.In addition, the device according to the invention can optionally have a bypass unit 8, as shown in Figure 2, which jointly provides the accumulator charging function described above and, if appropriate, filtering and cooling functions for the impeller unit 4 and the guide vane unit 9. If the impeller unit is designed according to Figure 1b, the bypass unit 8 is no longer optional. In addition, the guide vane unit 9 can be designed analogously to the impeller unit according to Figure 1b, ie the pump arrangement 9.3 has only one pump, and the connecting lines from the pump arrangement 9.3 to the collection and equalization tank are omitted. In this case, the hydraulic cylinder 9.6 must act as a synchronized cylinder. Optionally, in this case too, the pump of the pump arrangement 9.3 can be supplied with flushing oil via the bypass unit 8.

[0044] Finally, it should be mentioned that there are Kaplan machines in which the impeller blades must be set to a predefined position in the event of an emergency shutdown. This must continue to function even if the first pump arrangement 2 fails. To achieve this, an impeller unit 4 according to the invention can easily be equipped with the elements required for emergency shutdown functionality. These are the same elements that are used in a guide vane unit 9 for emergency shutdown. These are at least the elements 9.71 (emergency shutdown valve), 9.72 (emergency shutdown solenoid valve) and at least one throttle. As with a guide vane unit 9, the energy required for emergency shutdown then comes from the storage unit s. Further optional elements, e.g.for a quick closure, or if more than one throttle is to be used to adjust the maximum closing speed, can easily be integrated into the impeller unit 4 in a similar way to the designs in DE 10 2017 106 693 B3.

[0045] The inventors redesigned a total of six different Kaplan machines, which had previously been conventionally designed (see the second section of this document), according to the present invention. They compared the inventive design with the conventional design in terms of required storage volume, storage costs, and tank volume. Considering only the impeller adjustment, the following average reductions were achieved with the inventive design:

[0046] - Storage volume: - 77%

[0047] - Storage costs: - 66%

[0048] - Container volume: -54%

[0049] When considering the combined impeller and diffuser adjustment, the following average reductions were achieved with the inventive design:

[0050] - Storage volume: - 69%

[0051] - Storage costs: - 58%

[0052] - Container volume: -62%

[0053] List of reference symbols

[0054] 1 collection and compensation tank

[0055] 2 First pump arrangement

[0056] 3 Second pump arrangement

[0057] 4 Impeller unit

[0058] 5 storage

[0059] 6 hydraulic cylinders

[0060] 7 Rotary union

[0061] 8 Bypass unit

[0062] 9 Control unit

[0063] 4.1 Check valve

[0064] 4.2 Pilot valve

[0065] 4.3 Check valve

[0066] 4.4 Pilot valve

[0067] 4.5 Pressure relief valve

[0068] 4.6 Pressure relief valve

[0069] 4.7 Check valve

[0070] 4.8 Pilot valve

[0071] 4.9 Throttle

[0072] 4.10 Flow sensor

[0073] 4.11 3 / 2-way valve

[0074] 4.12 Throttle

[0075] 4.13 Check valve

[0076] 4.14 Pilot valve

[0077] 8.1 Third pump arrangement

[0078] 8.2 Filter unit

[0079] 8.3 Cooling unit

[0080] 9.3 Pump unit of the distributor unit

[0081] 9.5 Control unit memory

[0082] 9.6 Hydraulic cylinder of the guide vane unit

Claims

Patent claims 1 . Device for controlling a hydraulic machine of the Kaplan type with an impeller unit (4) comprising a first pump arrangement (2) with a variable-speed pump drive, an accumulator (5), a hydraulic cylinder (6), two releasable check valves (4.1, 4.3) and two pilot valves (4.2, 4.4) for releasably releasing the check valves (4.1, 4.3), wherein the first pump arrangement (2) comprises at least one pump with a reversible delivery direction, which is connected to the variable-speed pump drive such that the pump can be driven in both delivery directions by the pump drive, and wherein the device further comprises a collecting and equalizing tank (1), characterized in that the impeller unit (4) comprises a second pump arrangement (3) with a variable-speed pump drive, a rotary feedthrough (7), a throttle (4.9), two further releasable check valves (4.7, 4.13) and two further pilot valves (4.8, 4.14) for unlocking the further check valves (4.7, 4.13), and wherein the second pump arrangement (3) comprises a further pump with a reversible delivery direction, which is connected to the associated variable-speed pump drive in such a way that the further pump can be driven in both delivery directions by the pump drive, and wherein a first connection of the first pump arrangement (2) is connected via a first control line and via the rotary feedthrough (7) to a first side and a second connection of the first pump arrangement (2) is connected via a second control line and via the rotary feedthrough to a second side of the hydraulic cylinder (6), and wherein a releasable check valve (4.1, 4.3) is located in sections of the control lines which extend from the first pump arrangement (2) to the rotary feedthrough (7) and which are aligned in such a way that in each state of the check valves (4.1, 4.3) Hydraulic fluid passed in the direction of the rotary union (7). can be, and wherein one side of the pump of the second pump arrangement (3) is connected to the collecting and equalizing tank (1) and the other side is connected via a pressure line to a section of the first control line, which extends between the respective check valve (4.1) and the rotary feedthrough (7), and wherein a check valve (4.13) is arranged in the pressure line, which is aligned such that in every state of the check valve (4.13) hydraulic fluid can be passed through in the direction of the first control line, and wherein the accumulator (5) is connected via the throttle (4.9) to a section of the second control line, which extends between the respective check valve (4.3) and the rotary feedthrough (7), and wherein a check valve (4.7) is arranged parallel to the throttle (4.9) such that in every state of the check valve (4.7) hydraulic fluid can be passed through the check valve (4.7) can reach the accumulator (5) from the second control line, and wherein the impeller unit (4) further comprises lines which connect the accumulator (5) to the check valves (4.1, 4.3, 4.7, 4.13) in order to be able to unblock the check valves (4.1, 4.3, 4.7, 4.13), and wherein the pilot control valves (4.2, 4.4, 4.8, 4.14) are each arranged in the lines between the accumulator (5) and the check valves (4.1, 4.3, 4.7, 4.13) in such a way that one of the pilot control valves (4.2, 4.4, 4.8, 4.14) can unblock a check valve (4.1, 4.3, 4.7, 4.13).

2. Device according to claim 1, wherein the device comprises a bypass unit (8), and wherein the bypass unit (8) is connected to the collection and equalization tank (1) and the accumulator (5), and wherein the bypass unit (8) comprises a third pump arrangement (8.1), and wherein the third pump arrangement (8.1) comprises a drive and a pump connected to the drive.

3. Device according to claim 1 or 2, wherein the hydraulic cylinder (6) is designed as a synchronous cylinder.

4. Device according to claim 1 or 2, wherein the hydraulic cylinder (6) is designed as a differential cylinder.

5. Device according to one of the preceding claims, wherein the first pump arrangement (2) comprises a first pump and a second pump, each with a reversible delivery direction, which are connected to the variable-speed pump drive such that the pumps can be driven in both delivery directions by the pump drive, and wherein a connection of the first pump is connected via a first control line and via the rotary union (7) to a first side and a connection of the second pump is connected via a second control line and via the rotary union to a second side of the hydraulic cylinder (6), and wherein the remaining connections of the first and second pumps are each connected to the collection and equalization tank (1),so that in a drive direction of the first pump arrangement (2), the first pump can pump hydraulic fluid from the collecting and equalizing tank (1) in the direction of the hydraulic cylinder (6) and the second pump can pump hydraulic fluid from the side of the hydraulic cylinder (6) into the collecting and equalizing tank (1).

6. Device according to claim 2 and 3, wherein the first pump arrangement (2) comprises exactly one pump with equal flow rates in both directions of rotation, and wherein the connections of the pump are connected to the control lines.

7. Device according to claim 6, wherein the pump of the first pump arrangement (2) is designed as a 4Q piston pump.

8. Device according to claim 7, wherein the pump of the first pump arrangement (2) comprises a flushing oil connection which is connected to the bypass unit (8), and wherein a throttle is arranged in the corresponding connecting line, and wherein in a A pre-stressed check valve is arranged in the return line from the bypass unit (8) to the collecting and equalizing tank (1).

9. Device according to one of the preceding claims, wherein the impeller unit (4) comprises a further throttle (4.12) and a 3 / 2-way valve (4.11), wherein the throttle (4.12) and the 3 / 2-way valve (4.11) are arranged in a line which extends from the pressure line to the collecting and equalizing tank (1).

10. Device according to one of the preceding claims in conjunction with claim 4, wherein the second control line is connected to a rod side of the hydraulic cylinder (6).

11. Device according to claim 4 or 10 in conjunction with claim 5, wherein the first and second pumps of the first pump arrangement (2) are designed as gear pumps.

12. Device according to one of the preceding claims in conjunction with claim 9, wherein the pump of the second pump arrangement (3) is designed as a gear pump or as a piston pump without flushing.

13. Device according to one of the preceding claims, wherein the impeller unit (4) comprises a flow sensor (4.10) which is arranged in the line extending between the reservoir (5) and the second control line.

14. Device according to one of the preceding claims, wherein the impeller unit (4) comprises two pressure relief valves (4.5, 4.6), one of which is connected to the first control line and the other to the second control line.

15. Device according to one of the preceding claims, wherein the impeller unit (4) comprises a further throttle, an emergency shut-off valve (9.71) and an emergency shut-off solenoid valve (9.72).

16. Device according to one of the preceding claims, wherein the device comprises a guide unit (9) which is connected to the collecting and equalizing tank (1).

17. Device according to claim 2 and 16, wherein the guide unit (9) comprises a reservoir (9.5), and wherein the bypass unit (8) is connected to the reservoir (9.5) of the guide unit (9).

18. Device according to one of claims 2 to 17, wherein the bypass unit (8) comprises a filter unit (8.2).

19. Device according to one of claims 2 to 18, wherein the bypass unit (8) comprises a cooling unit (8.3).

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