The present invention relates to a hydraulic accumulator rack arrangement as defined in the preamble of claim 1 .

Hydraulic energy is used in many various purposes as a power source. For instance, it can be used in various production or manufacturing machines, such as machine presses, punching machines, which must be able to produce a great force in a very short time. It can also be used in many other heavy machineries, such as in mining, earthmoving and construction-equipment machinery, as well as in agriculture. Hydraulic energy can also be used in the production of renewable energy, for example in the recovery of wind or wave energy.

Usually, hydraulic energy is produced by hydraulic pumps. In order to produce the required great force in a very short time, for instance for machine presses or punching machines, the hydraulic pump should be big and very powerful. Commonly that is not possible and therefore hydraulic or pressure accumulators are widely used as closest power sources for the applications which require that kind of great force in a very short time. In many cases also those accumulators must be rather large in order to be able to perform the task. This may lead to heavy and complicated constructions. For instance, single large size accumulators have a challenge to reliably separate the sides of oil and nitrogen gas because the sealings between the sides are subjected to heavy stress.

The energy recovered from the renewable energy sources, such as wind and/or wave energy, is often pulsating and/or fluctuating. For this reason, the recovered energy is often not usable as such, so it must be made smoother and more homogeneous first. Hydraulic accumulators are very capable for this kind of task.

If an actuator, such as a press or punching machine or another type of machine tool, is not used all the time, the hydraulic accumulator has enough time to be filled up and then to convey the required dose of energy when the actuator is used again. Such prior art solutions are presented for example in US5657824A, where a drive unit for a fire fighting installation operating with a high drive pressure has at least one drive gas container charged to high pressure and at least first and second groups of hydraulic accumulators selectively connectable to the at least one drive gas container and connections which initially connect only the first group of the hydraulic accumulators to the at least one drive gas container and subsequently connect the second group of hydraulic accumulators to the at least one drive gas container.

It is common knowledge to connect multiple pressure accumulators to one larger system to achieve larger pressure reserve for operations. In these cases, the identical pressure accumulators each having same pressure settings are connected to pipeline to create a system capable for larger capacity operations. The connections between the separate pressure accumulators are done with pipelines or pressure hoses. The connecting pressure lines create a large web between the pressure accumulators and operated solution(s).

The prior art solutions are not as compact, not as robust, have more complicated parts being less cost effective, have not adjustable operational curve, have less connection opportunities and the setting is impossible or difficult to modify. Also, single big accumulators (instead of a set of small ones) have a challenge to separate reliably the oil and nitrogen gas sides (sealings in between). This is due to the more demanding manufacturing process of the bigger accumulators. Smaller accumulators are also more convenient for serial production.

The present invention creates a hydraulic accumulator rack arrangement which enables to connect multiple hydraulic accumulators together with simple and reliable connector and enables compact and robust structure for pressure accumulators which is also easily encapsulated for protecting hydraulic devices of the rack, and for protecting other devices near the rack. The arrangement of the invention is capable for utilizing all types of pressure accumulators. The hydraulic accumulator rack arrangement creates a robust, compact size and easy to transport solution, which has extremely long lifetime with pulsating loads because it requires no hoses or pipes. It enables a possibility to adjust operational curve of the hydraulic accumulator rack. Normally, operation of one hydraulic accumulator follows equation k=PV ^A 1 .4, which means that operation curve is not linear. However, with the arrangement of the invention the multi-accumulator rack arrangement can have hydraulic accumulators with different prefill values of gas medium (typically nitrogen) that enables linear operation curve. The hydraulic accumulator rack arrangement according to the invention enables extremely large connection surface area to the hydraulic accumulators. This means that instead of one 2” connection, we can have for example 40 x 1 ” connections. This increases the connection surface area significantly when compared to the prior art solutions.

The present invention creates a simple, robust, compact, versatile, scalable and cost-efficient hydraulic energy/power storage with adjustable operational curve.

It is also possible to change, service or inspect, the hydraulic accumulators if necessary and failure in one hydraulic accumulator will not affect to the operation of the rack arrangement. It is possible to integrate functionalities/components to the connecting manifold or distribution manifold of the hydraulic accumulator rack arrangement.

The energy storage of the hydraulic accumulator rack arrangement can be used in multiple applications which need storing or smoothing of energy or rap- id/instantaneous power boosting or tolerance for pulsating loads with limited space and rough environment. The arrangement offers possibility to adjust operational curve of the accumulator rack.

In the following, the invention will be described in detail by the aid of examples by referring to the attached drawings, wherein

Fig. 1 presents a side view of the hydraulic accumulator rack arrangements first side,

Fig. 2 presents a top view of the hydraulic accumulator rack arrangement, Fig. 3 presents a side view of the hydraulic accumulator rack arrangements second side,

Fig. 4 presents a side view of the hydraulic accumulator setups first side of Fig. 1 without the rack,

Fig. 5 presents a top view of the hydraulic accumulator setup of Fig. 2 without the rack,

Fig. 6 presents a side view of the hydraulic accumulator setups second side of Fig. 3 without the rack,

Fig. 7 presents a perspective view of the connecting manifold of the hydraulic accumulator rack arrangement, and

Fig. 8 presents a side view of the connecting manifold of the hydraulic accumulator rack arrangement of Fig. 7.

Fig. 1 is a side view of the hydraulic accumulator rack arrangements 1 first side. The hydraulic accumulator rack arrangement 1 comprises a support structure 30 having corner structures in every corner of the box like support structure structure. The support structure 30 is keeping the hydraulic accumulators 7 in place and enable the easy moving of the hydraulic accumulator rack arrangement 1 . In Fig. 1 you can see the support structure 30 including a long horizontal upper corner structure 2 and a long horizontal lower corner structure 4. The long horizontal corner structures 2 and 4 are connected with vertical corner structures 3 at both ends. Same structure is also on the other side of the sets of hydraulic accumulators 7. In this embodiment there are six sets of hydraulic accumulators 7 (three visible in Fig. 1 ). Therefore, the long horizontal corner structures 2 and 4 are made of two separate pieces which are connected with a connecting piece 6 making the hydraulic accumulator rack arrangement 1 adjustable for many solutions having different number of hydraulic accumulator 7 sets. This allows the length of the hydraulic accumulator rack arrangement 1 to be easily modified for one or more of hydraulic accumulator 7 sets in the rack. The long horizontal corner structures 2 and 4 are advantageously connected to each other by some ad- ditional support structures 5 which give the structure more rigid/robust form. These support structures 5 can be vertical or in some angle. It is to be understood that the support structure can vary depending on the design and of the number of the hydraulic accumulators 7. In another embodiment the hydraulic accumulator rack arrangement 1 can be, as a whole or as in part, covered with cover plates to protect the hydraulic accumulators 7 and/or the surrounding environment.

The hydraulic accumulators 7 are connected to the connecting manifold 8. The hydraulic accumulators 7 can be connected to the connecting manifold 8 from both sides so that one connecting manifold can take in two sets of the hydraulic accumulators. Also, only one set of hydraulic accumulators 7 can be connected to the connecting manifold 8 and the unnecessary connections of the connecting manifold can be plugged closed. In Fig. 1 both options for the connecting manifold 8 are presented as the hydraulic accumulator rack 1 includes three visible sets of hydraulic accumulators 7.

The number of the hydraulic accumulators 7 in one set can be selected freely according to the demands of the use. In this embodiment there are five hydraulic accumulators 7 on top of each other. Also, the type of pressure accumulators 7 can be any type commonly available.

To the hydraulic accumulator rack arrangement 1 is attached distribution manifold 9. The distribution manifold 9 is a solid metal block comprising hydraulic lines inside and connections for necessary equipments/accessories/functionalities. The distribution manifold 9 is connecting several connecting manifolds 8 together creating one big hydraulic accumulator 7 arrangement. To this distribution manifold 9 are attached for example the incoming and outgoing pressure lines. The distribution manifold 9 comprises connections for any other necessary equip- ments/accessories/functionalities that could be attached to the distribution manifold such as valves. In this embodiment the distribution manifold 9 is directly connected to the first (left side) connecting manifold 8 with an angle connector 10 and to the second (right side) connecting manifold is connected with the pipes 11 and an angle connector 10. The angle connector 10 is simply a metal block comprising hydraulic channels inside which channels are connecting incoming and outgoing hydraulic flows and directing the flow to and from the connecting mani- fold 8. The angle connector 10 is used with a non-threaded opening in the connecting manifold 8 and in the distribution manifold 9 for the assembly reasons enabling easy assembly of the system.

If the hydraulic accumulator rack arrangement 1 comprises only one connecting manifold 8 there is no distribution manifold 9 present and then the equip- ments/accessories/functionalities that could be attached to the distribution manifold 9 can be attached directly to the connecting manifold 8.

Fig. 2 is a top view of the hydraulic accumulator rack arrangement 1 . In this embodiment the hydraulic accumulator rack arrangement 1 includes six sets of hydraulic accumulators 7, each set having 20 hydraulic accumulators. That makes total of 120 hydraulic accumulators 7 in the hydraulic accumulator rack arrangement 1. The embodiment comprises actually two similar rack modules side by side connected to each other with connecting pieces 13. The modular structure of the support structure 30 enables the flexibility of the hydraulic accumulator rack arrangement 1 . The long horizontal corner structures 2 are connected to each other with end support structure 12. This end support structure 12 can be a single plate or various number of separate flat structures like parts 5 in Fig. 1 . Advantageously, there are equal number of support structures 12 as there are pressure accumulators 7 on top of each other. The long horizontal corner structure 2 includes two parts that are connected to each other with connecting piece 6. This modular solution enables easy modifications of the hydraulic accumulator rack arrangement 1 structure. It is easy to add more sets of hydraulic accumulators 7 to the system or remove sets if necessary.

The four connecting manifolds 8 are connected to one distribution manifold 9. The left side connecting manifolds 8 directly with the angle connectors 10 and the right side manifolds 8 with pipes 11 and angle connectors 10.

Fig. 3 presents a side view of the hydraulic accumulator rack arrangements 1 second side. One end support structure 12 is removed to show the four hydraulic accumulators 7 inside the hydraulic accumulator rack arrangement 1. The hydraulic accumulators 7 have connections 7a for gas medium (preferably nitrogen) through which connections 7a the hydraulic accumulators 7 can be in advance set to desired pressure settings. Each hydraulic accumulator 7 can be set to indi- vidual pressure setting so that the whole system can be tuned to desired operational curve. The support structure 30 of the hydraulic accumulator rack arrangement 1 comprises vertical corner structures 3, long horizontal upper corner structures 2, long horizontal lower corner structures 4 and end support structures 12. The end support structures 12 have openings for hydraulic accumulators 7 connections 7a for easy maintenance and setting of the hydraulic accumulator. The two parallel hydraulic accumulator rack modules are connected to each other with connecting parts 13.

The angular connectors 10 are connecting the distribution manifold 9 to the upper side of the connecting manifold 8. The distribution manifold 9 comprises connections 14 for any necessary connections to be made available. It is possible to connect the distribution manifold 9 to any of the four sides of the connecting manifold 8.

Fig. 4 presents a side view of the hydraulic accumulator setups first side of Fig. 1 without the rack. In this Fig. 4 you can clearly see the pressure accumulators 7 connected to the connecting manifold 8. The left connecting manifold 8 is directly connected to the distribution manifold 9 with the angle connector 10 and the right connecting manifold 8 is connected with angle connector 10 and pipes 11 .

Fig. 5 presents a top view of the hydraulic accumulator setup of Fig. 2 without the hydraulic accumulator rack. The hydraulic accumulators 7 have the connections 7a for the pressure settings and maintenance of the hydraulic accumulators. The hydraulic accumulators 7 are connected to the connecting manifold 8. The left connecting manifolds 8 are directly connected to the distribution manifold 9 with the angle connectors 10 and the right connecting manifolds 8 with angle connectors 10 and pipes 11. The distribution manifold comprises connections 14 for any necessary equipments/accessories/functionalities.

Fig. 6 presents a side view of the hydraulic accumulator setups second side of Fig. 3 without the hydraulic accumulator rack. The hydraulic accumulators 7 have the connections 7a for the pressure settings and maintenance. The hydraulic accumulators 7 are connected to the connecting manifold 8. The connecting manifold 8 is connected to the distribution manifold 9 with angle connector 10. The distribution manifold 9 comprises connections 14 for any necessary equip- ments/accessories/functionalities.

Fig. 7 presents a perspective view of the connecting manifold 8 of the hydraulic accumulator rack arrangement. The connecting manifold 8 in this embodiment is a solid metal block which comprises openings 16, 17 and 18 in x- y-, and z- directions. The openings 18 for the hydraulic accumulators are in the x-y -plane, openings 17 are in y-z -plane and openings 16 in x-z -plane. These openings 16, 17, and 18 extend through the connecting manifold 8 forming hydraulic lines 16a, 17a and 18a which hydraulic lines 16a, 17a and 18a are forming a 3D-mesh of hydraulic lines inside the connecting manifold. This 3D-mesh distributes the hydraulic pressure evenly to all openings 16, 17 and 18 of the connecting manifold 8. The openings 16, 17 and 18 have threads so that any necessary equip- ments/accessories/functionalities and hydraulic accumulators can be connected to the connecting manifold 8. Any of the openings 16 and 17 can also be threadless if any connected means requires non-threaded connection. This is the case with the connection of the angle connector.

The connecting manifold 8 enables easy, compact and simple assembly of the hydraulic accumulators to the hydraulic accumulator rack arrangement when the hydraulic accumulators are connected to the threaded openings 18. The assembly enables the compact positioning of the hydraulic accumulators and compact hydraulic accumulator rack arrangement. The connecting manifold 8, and if necessary, the distribution manifold 9, eliminates the use of pressure pipes and pressure hoses for connecting the hydraulic accumulators together. This makes the assembly faster, more compact, and more reliable in use. The connecting manifold 8 and distribution manifold 9 have long lifetime in pulsating pressure environment. Commonly used solutions with pipes and hoses take more space and are more complex than the present solution. The robust hydraulic accumulator rack arrangement also enables easy transportation of the hydraulic accumulators to the site of use and setting the arrangement already at factory with desired pressure curve. At the site of use only minor assembly is needed compared to prior art systems which require number of pipes or hoses and accessories to be assembled at the site. It is also possible to leave some openings 16, 17 or 18 without the threads as is done with opening 19 situated to the narrow side of the connecting manifold 8 with openings 16. This opening 19 is in this embodiment used for connecting the angle connector 10 presented in Figs. 1 -6 to the connecting manifold 8. The angle connector is attached to the connecting manifold with threaded holes 21 and connecting bolts. Opening 19 is used as a line for the incoming and outgoing pressure medium and for assembly reasons is not threaded.

In this embodiment the connecting manifold 8 comprises 20 openings 18 for the hydraulic accumulators at one side of the connecting manifold and same number of openings 18 at the opposite side of the connecting manifold 8 in x-y -plane. Other openings 16 and 17 situated to the narrow sides of the connecting manifold 8 are used for other connections, such as incoming/outgoing pressure medium, valves, safety valve, etc. If the openings are not in use, they are easily plugged closed. The large number of possible connections of the connecting manifold 8 enables easy modifications to the hydraulic accumulator rack arrangement.

The connecting manifolds 8 can be manufactured in different sizes for different sized hydraulic accumulators and for different number of hydraulic accumulators in the system. Also, the number of sets of hydraulic accumulators in the hydraulic accumulator rack arrangement and the rack modules combined together are enabling a flexible arrangement.

Fig. 8 presents a side view of the connecting manifold 8 of the hydraulic accumulator rack arrangement. Part of the connecting manifold 8 is drawn open so that the pressure lines 16a, 17a and 18a can be seen. The openings 18 in x-y -plane are threaded for the assembly of the pressure accumulators and are forming pressure line 18a for the pressure medium. Opening 19 is executed without threads for the connection of the angle connector for incoming and outgoing pressure medium. Other openings 16 and 17 at the x-z and y-z -planes of the connecting manifold are threaded and are forming pressure lines 16a and 17a inside the connecting manifold 8. All pressure lines 16a, 17a and 18a are forming a 3D-mesh inside the connecting manifold 8 so that the pressure medium is freely moving inside the connecting manifold and between the hydraulic accumulators. The pressure lines 16a, 17a and 18a are in 90-degree angle to each other. It is also possible to manufacture the connecting manifold 8 so that the pressure lines 16a, 17a and/or 18a are only open at one side of the connecting manifold. This reduces the possible number of connection points and reduces the need for plugging the openings 16, 17 and/or 18 closed.

The solution of the present invention enables to modify the pressure curve of the outcoming pressure medium. This is done by presetting different pressure settings to separate hydraulic accumulators. If only one big hydraulic accumulator, according to prior art solutions, is in use the pressure curve is not linear. The nitrogen inside the hydraulic accumulator (or in separate gas station) behaves with adiabatic reaction (not isothermal) and therefore the pressure curve is not linear. With multiple hydraulic accumulators connected together with connecting manifold the pressure curve can be optimized for the most effective use of the hydraulic accumulators. If a linear pressure curve is needed the presettings of the hydraulic accumulators can be set to achieve such curve. The pressure curve can be modified to fulfill any needs of the different uses of the hydraulic accumulators. The hydraulic accumulator rack arrangement is also easier to transport to the site of use than one big hydraulic accumulator. The hydraulic accumulator rack arrangement can be assembled at the factory to ready to use condition, transported to the place of use and with minimum work required connected to the main pressure line.

The flow of the pressure medium is faster in the solution according to the invention than the flow of the solution including one big hydraulic accumulator. The incoming pressure medium can be taken into the pressure accumulators through openings that can be for example 40x1 ” compared to one big accumulator having only one 2” opening for intake.

The regulations for pressurized vessels are more demanding when the pressure is increased so dealing with smaller pressures and larger number of accumulators gives advantages over solution with one or few big vessel(s). Also, smaller connections are easier to make and are safer/reliable to use.

If only one or few big hydraulic accumulators are used together the system is not sensitive for pressure changes. With multiple small hydraulic accumulators adjusted for separate pressure settings the system is very sensitive for pressure changes and reacts easier and more precisely to the changes. Also, taking the pressure medium out of one big connection the flow through the hole slows down and the efficiency drops.

It is possible to install all necessary actuators to the top of the hydraulic accumulator rack arrangement and keep the pipes and hoses to the minimum (actuators connectable directly to the distribution manifold or to the connecting manifold). Depending on the place of use the connecting manifold is providing multiple connecting openings around the hydraulic accumulator rack arrangement so that the assembly of necessary equipments/accessories/functionalities or connections can be made easily. The connections can be all at one side of the connecting manifold or divided to two or more sides of the connecting manifold.

The maintenance of the hydraulic accumulator rack arrangement is easier than maintenance of one or few bigger hydraulic accumulator(s). It is easy to replace or take out of use one or more accumulators without significant disadvantage to the use of the whole system. Also, if one or two hydraulic accumulators are broken down the system is still operatable. It is easy to find broken/inactive hydraulic accumulators by the use of thermal imaging. The broken/inactive hydraulic accumulator can be warmer or colder than properly operating hydraulic accumulator depending what is the reason for the malfunction.

The connecting manifold enables to connect a large number of hydraulic accumulators together into a compact hydraulic accumulator rack arrangement according to the present invention. The number of hydraulic accumulators connected to the one side of the connecting manifold can be varied freely depending on the needs of the operated system/device. One typical solution is to have 24 hydraulic accumulators connected to one side (x-y -plane) of the connecting manifold which results to total of 48 hydraulic accumulators connected to one connecting manifold. These modular sets of hydraulic accumulators can be connected together to fulfill the present need of the operation. The pre-filling pressure of the 24 hydraulic accumulators can vary for example from 150 bar to 180 bar so that 6 accumulators each have 150 bar, 160 bar, 170 bar and 180 bar. This gives more linear operation curve than having 24 hydraulic accumulators at 165 bars. It is understood to the man skilled in the art that the number of the hydraulic accumulators and the pre-filling pressures can vary depending on the needs of the operated sys- tem/devise. The hydraulic accumulator rack arrangement is here presented to comprise only pre-filled separate hydraulic accumulators. It is also clear that these hydraulic accumulators can have separate gas station(s) connected to the hydraulic accu- mulators gas side, which is common knowledge to the man skilled in the art.

The hydraulic accumulator rack arrangement is more reliable than arrangements according to the prior art. It has extremely long lifetime with pulsating load compared to arrangements with pipes and hoses.