EP1384900A1 - Hydraulic accumulator - Google Patents

Abstract

The accumulator has a two-part (12,32) housing (10) with an internal divider diaphragm (14), made of elastomer material, dividing it into a gas chamber (20) and a fluid chamber (22). The gas chamber is connected via a connection device to a gas refill unit formed by a third housing part (34), which is connected to the accumulator housing to form a modular unit. The connection unit consists of at least one connection aperture (36) in the housing connecting the interior of the third housing part and the gas chamber. The third part encloses a first housing part, which defines the gas chamber. All housing parts are connected via a common weld seam (46).

Description

The invention relates to a hydraulic accumulator, in particular diaphragm accumulator, with a storage enclosure consisting of at least one or several, in particular two housing parts and a therein Separating element, in particular in the form of a separation membrane, the storage enclosure divided into a gas space and a fluid space, wherein the Gas space with a Gasnachfülleinrichtung via a connecting device Gas leading is connected.

Hydraulic accumulators of the type mentioned are preferred in hydrosystems used, inter alia, for energy storage, for an emergency operation of hydraulic systems, shock absorption etc. The hydraulic accumulators are by definition considered to be pressure vessels by Depending on the intended use, a specific useful volume can be stored. Usually, hydraulic accumulators are distinguished by a separating element in bladder accumulator, diaphragm accumulator and piston accumulator, wherein the Mode of action based on the fact that the compressibility of a working gas is used for fluid storage. As a rule, nitrogen is used as Working gas. The partition divides the hydropneumatic accumulators in a gas part and in a liquid part, the latter with the hydraulic Circulation is connected, so that when the Drukkes increase compressed on the fluid side, the gas on the gas side in the gas space and, accordingly, at a pressure drop on the fluid side, the compressed gas expand and the stored fluid in the memory again thereby push back into the hydraulic circuit.

Since the separating element regularly in the form of a separating membrane of elastomeric material subject to a particular gas permeability, this leads in particular with prolonged use of the hydraulic accumulator to the working gas diffused through the separation membrane to the fluid side of the memory and is lost in this way. The working capacity of the hydraulic accumulator decreases thus continuously. To counter this, is in the so-called bubble stores already been proposed on the gas side of the memory this specially provided for the connection of pressure vessels, with over a Piping as connecting means the gas side of the hydro bubble reservoir permanently in gas-conducting connection with the pressure vessel, then preferably as Gasnachfülleinrichtung for the respective working gas in the form of nitrogen. Basically, about the Gasnachfülleinrichtung not actually gas in the hydraulic accumulator tracked, rather, the gas volume is due to the addition of the volume of the gas Gas space in the store and the gas space in the pressure accumulator adds, so that partial gas losses due to diffusion across the separation membrane the total volume of stored working gas and withdraw the service life of the hydro bubble reservoir can be designed accordingly extend. In addition, there is a lower pressure increase at the same displaced fluid volume.

It has now been found in practice that in the case of the trained Solutions due to the separate arrangement of hydraulic accumulator and Pressure vessel as Gasnachfülleinrichtung much installation space is needed and the existing piping as a connecting device between the said containers regularly has leaks, so that at the advantage that you get about the additional Gasnachfülleinrichtung wants, at least partially lost again. Further is the said piping as permanently gas-conducting connection means between the mentioned containers first, so that not only through the piping itself production costs arise, but more Costs associated with assembly activities.

The above bladder accumulator with permanently connected Gas refilling device is characterized in that the separating membrane is designed in the manner of a gas bubble and the filling of said bubble takes place through the gas valve located at the upper part of the hydraulic accumulator, that as part of the connecting device open to the piping and thus connected to the gas refilling device. Because of the Use coming large-volume pressure vessel as Gasnachfülleinrichtung you have the pending Nachschaltausführung regularly only at large-volume hydraulic accumulators used, such as the bladder memories, or in piston accumulators, in which the separating element of a within the storage enclosure movable, sealed separating piston consists in the latter solution, the diffusion of the gas to Fluid side through the sealing device on the outer circumference of the separating piston takes place, on the inner peripheral side of the hydraulic accumulator housing for slides along a corresponding operation of the memory.

Based on this prior art, the invention has the object based, the previously described and known hydro storage solution to further improve such that a corresponding gas refill also can be used for diaphragm accumulator with the proviso of a cost-effective and functionally reliable solution that requires little installation space and cheap in the manufacture, installation and maintenance is. A task solves a hydraulic accumulator with the features of claim 1 in his Entirety.

Characterized in that according to the characterizing part of claim 1 the gas refilling device from at least one further housing part is formed with the memory housing to form a structural unit is connected, and that the connecting means of at least one Connection opening in the storage enclosure, which is the interior of the other Housing part connects to the gas space, is the Gasnachfülleinrichtung in the form of a further housing part of the memory on the actual Storage housing with the gas space and the fluid space and placed over the immediately existing connection device between the gas space the storage housing and the interior of the further housing part, with its internal volume also the intake of the working gas serves, the known piping is avoided, which costs and installation space saves for the total solution of the thus supplemented hydraulic accumulator. There by dispensing with the piping it is in the area of the junction between Piping and the respective memory and gas tank as Gasnachfülleinrichtung no longer can lead to leaks is avoided the pertinent problem with the solution according to the invention and also over a longer stand or duration of use of the hydraulic accumulator it comes to gas losses through diffusion processes on the separator especially in the form of a separation membrane not at a loss of the working gas required for the function of the memory, in particular in the form of nitrogen gas. The execution prevents the Membrane is inhibited at pressure peaks in their movement and it can not to a, the membrane damaging overstretching in the gas space come.

In a preferred embodiment of the hydraulic accumulator according to the invention the further housing part comprises the one housing part of the storage housing Outside circumference, which limits the gas space of the memory. Preferably, it is provided that the other housing part, the limited at least the fluid space, at its free, the one housing part facing edge forms a paragraph on which the free end of the other Housing part can be placed. This can be easier during installation Make the other housing part on the actual storage enclosure placed on the hydraulic accumulator and then connected with this be so basically that in a single operation with three housing parts the storage solution according to the invention can be realized.

In a further particularly preferred embodiment of the invention Hydraulic accumulator are all three housing parts on their front side Ends via a common junction, preferably in Form a weld, interconnected, with the weld od also via a laser process. Like. Can be realized. That's how it works So with a single operation in a cost effective manner the overall assembly reach the hydraulic accumulator.

In one embodiment of the hydraulic accumulator according to the invention the separating element is made of an elastomeric material held by a fastening ring, which leaves the connection point on the inner peripheral side of the storage housing. In this case, in a further advantageous embodiment, the one housing part, which at least partially comprises the gas space, with a step-shaped shoulder at its free fastening edge cover the connection point inwards. Thus, it is avoided that any hot welding materials or weld spatter can penetrate into the interior of the hydraulic accumulator, so as to damage the separation membrane. Rather, ends the inner peripheral side, the weld on the stepped shoulder of a housing part.
In an alternative embodiment, such a covering could also be formed by the upper end of the above-mentioned fastening ring.

In a further particularly preferred embodiment of the invention Hydraulic accumulator is the capacity of the other housing part about twice the storage volume of the storage enclosure on his gas side. The pertinent embodiment with the above Volume ratios have become particularly important for diaphragm accumulators proved favorable and allows a significant extension of the service life of the memory through the attached nitrogen downstream. It is doing a surprising job for a person skilled in the field of hydraulic accumulators, that he doing the wall thickness of the other housing part, the Nitrogen Nachschaltung serves, compared to the wall thickness of the other two Can reduce housing parts of the storage enclosure, in particular about can train as strong, without this leading to safety impairments for the memory leads. In particular, the inventive Arrangement designed such that the free mobility of the membrane is restricted accordingly and not on the gas side of the other Memory housing can escape.

If preferably the separating element is provided with a stop member, with which the fluid connection of the storage housing is closable, it is ensured that at a complete emptying of the storage enclosure of fluid, the separating element not via the fluid port in the direction of Hydrokreises can be sucked, causing damage to the membrane material would lead.

Furthermore, it has proven to be advantageous, all housing parts in the area of their Cylindrical connection form and at least at their end sides provide partially curved end pages. The resulting design has to be initiated with regard to the in the storage enclosure Compressive forces proved favorable and the hydraulic accumulator is accordingly functionally reliable.

Since the Gasnachfülleinrichtung is very compact executable, is with the described Solution now also readily the use of a Gasnachfülleinrichtung for usual diaphragm accumulator possible, which so far not the case was because of the large-volume pressure accumulator as a gas refilling device such arrangements with piping only for bubbles or Piston accumulator has been used.

Fig.1

teilweise im Schnitt, teilweise in Ansicht eine bekannte Gasnachfülleinrichtung, bestehend aus einem Blasenspeicher und einem Druckbehälter;

Fig.2

einen Längsschnitt durch den erfindungsgemäßen Hydrospeicher.

In the following, the hydraulic accumulator according to the invention will be explained in more detail with reference to an embodiment according to the drawing. This show in principle and not to scale representation of the

Fig.1

partly in section, partly in view a known Gasnachfülleinrichtung consisting of a bladder accumulator and a pressure vessel;

Fig.2

a longitudinal section through the hydraulic accumulator according to the invention.

FIG. 1 shows a hydraulic accumulator in the direction of view on its left side in the form of a bubble store. The pacemaker memory has a Storage housing 10, consisting of a contiguous housing part 12. In the storage housing 10, a separating element 14 is guided in Shape of a bubble made of a rubber-elastic material (elastomer). The The bubble is filled by the upper part of the storage housing 10 located gas connection part 16. The seen in the direction of view at the bottom End of the hydraulic accumulator attached liquid valve 18 in the Art a poppet device prevents in the first place that the bubble during Outflow of the fluid is sucked out. The provision of Valve device takes place in the usual way via a corresponding, not shown compression spring. Furthermore, the separating element 14 divides the storage housing 10 in a gas space 20 and in a fluid space 22nd

On its upper side, the known memory is provided with an adapter 24, which establishes the connection between the gas space 20 via the gas connection part 16 to a designated as a whole with 26 piping in Shape of single pipe pieces. Thus, the piping 26 opens with her a free end to the adapter and with its other free end a pressure vessel 28 as Gasnachfülleinrichtung. If now due the elastomeric storage bubble it to gas losses in the gas space 20 of the storage enclosure 10 comes, by diffusion processes of the working gas usually in the form of nitrogen through the separator 14 through in Direction to the fluid space side 22 of the memory, the pertinent Losses of working gas over the more available volume within the pressure vessel 28 at least over a predefinable Balanced period, which also with pressurized working gas is filled and makes the refilling via the piping 26.

Even if you install the piping 26 carefully, it is not excluded that it in particular at the connection points 30 to leakage problems with corresponding gas losses occurs, so that the gas loss is caused not only on the part of the memory bubble, but also by the Gas refilling device in the form of the pressure vessel 28 with piping 26 and adapter 24. Another leak is due to the connection point 30 between adapter 24 and outlet side of the gas connection part 16th Furthermore, Fig.1 makes it clear that the known solution constructively large builds and due to the variety of parts (adapter, piping, separate pressure vessel etc.), both the production and the subsequent maintenance is costly.

In the inventive solution according to Figure 2 are those described above Disadvantages in the prior art avoided with certainty. Of the hydraulic accumulator according to the invention, here in the form of a so-called membrane accumulator, with in the initial state in cross-section W-shaped separation membrane as a separating element 14 as shown in FIG. 2, has a storage housing 10 on with a first housing part 12 and another second Housing part 32. The partition member 14 in the form of the W-shaped separation membrane subdivides the storage housing 10 in turn into a gas space 20 and a fluid space 22, wherein in the present solution, the gas space 20 also with a Gasnachfülleinrichtung via a connecting device Gas leading is connected. The gas refilling facility in the present case consists of a further third housing part 34, the with the storage enclosure 10 to form a compact unit is connected, said connecting means of at least a connection opening 36 in the storage housing 10, which is the interior 38 of the other third housing part 34 with the gas space 20 of the hydraulic accumulator combines. In addition to the connection opening 36 shown can several, also smaller in diameter passage points in the assigned Housing part be present.

As can be seen from Fig.2 further, the further housing part comprises 34 the one housing part 12 of the storage housing 10 on the outer peripheral side, wherein the one housing part 12 in the initial state of the memory anyway the respective proportions of the gas space 20 limited, the pertinent Gas filling volume between the first housing part 12 and the top of the separating element 14 is enclosed.

The other housing part 32, which limits at least the fluid space 22, allows the inclusion of fluid connectable via the fluid port 40 Hydrocircle (not shown), as well as the volume of the gas space 20 may vary. Depending on the pressure conditions within the storage enclosure 10 and the quantities of fluid received can the separating element 14 between the inside of the second Housing part 32 and the corresponding inner side of the first housing part 12 move, and was between the connection point for the fluid connection 40 and the connection opening 36.

The other housing part 32 forms at its free, the one housing part facing edge of a paragraph 42, to which the respective free end of the second housing part 32 and the third housing part 34 can be placed. There Consequently, all housing parts 12, 32 and 34 with their facing each other Touching ends along a common edge line 44, can be over a common connection point 46, preferably in the form of a connecting weld (not shown), the assembly in the form of a Realize total hydraulic storage. The separating element 14 in the form of Separation membrane is at its bead-like widened end in a mounting ring 48, with its free end face 50 in the direction of view 2 seen below the edge line 44. If you pull that upper edge of the fastening ring 48 in a not shown Embodiment further upward, the edge thus obtained can Cover joint 46 in the form of the weld inwards and such is avoided that any weld spatter od. Like. Inside could damage the sensitive separation membrane. At the present Embodiment is provided, however, that the one housing part 12, which at least partially comprises the gas space 20, with a stepped Paragraph 52 at its free attachment edge against the junction 46, so that the same protection described above is obtained. About the thus obtained paragraph 52 is also an internal centering obtained for the first housing part 12, which is a touchdown and facilitates the assembly of the hydraulic accumulator.

In particular, the capacity of the other third housing part 34 is about twice as large as the storage volume of the storage enclosure 10 on its gas side 20. Thus, the following calculation example results for the extension of the operating time by the nitrogen downstream. In the case of the membrane memory shown, let p _o = 10 bar apply as initial pressure, with a gas volume in the gas space 20 of V _o = 0.5 l, which corresponds to a gas volume of 5Nl (standard liters). The loss of gas over a predefinable time x may be 2 Nl. This results in a difference of 5Nl - 2Nl = 3Nl and this in turn follows a gas pressure of 3Nl / 0.5l = 6 bar, after the aforementioned period x. The pressure loss due to the mentioned gas loss of 2Nl is then 4 bar after said period x.

In the event that the above-described membrane memory is provided with a nitrogen downstream, again results for an output pressure of p _o = 10 bar, a gas output volume V _o of 11, with respect to the previous example 0.51 by the gas volume of the third housing part 34 with is applied to his interior. This results in a total gas volume of 10NI. The gas loss over the predeterminable period x should be again 2Nl, which gives a pressure drop of 2 bar after the time x. 10Nl - 2Nl give 8NI, resulting in a gas pressure of 8/1 = 8 bar after time x. The working example described above makes it clear that the possibility of gas refilling, which is an integral part of the membrane hydraulic accumulator, can significantly increase the service lives for the relevant membrane accumulators.

As further shown in Figure 2, the wall thickness of the other housing part 34 against the wall thickness of the other two housing parts 12,32 be substantially reduced, in particular about half as strong be like the housing walls of the storage enclosure 10. The separator 14 itself is provided with a bottom-side stop member 54, However, what is customary for such hydraulic accumulators, so that at this Job will not be discussed in detail. Ultimately, that serves Stopper member 54 to pull out with emptied memory on the fluid side the elastic separating element 14 via the fluid port 40 to avoid what permanently damage the sensitive membrane material could. On the stop member 54 is rather a defined closing the fluid port 40 without the described disadvantage possible, so that the stop member 54 has a similar function as the already described poppet valve 18 in the initially described Bubble memory.

All housing parts 12,32,34 are in the range of their connection, ie in the area the junction 46, cylindrically shaped, wherein they at their End sides at least partially curved end sides 56 have what in particular within the storage enclosure 10 is so far favorable, as the separator 14 then gently in the maximum end positions lean against the housing parts of the storage enclosure 10 supporting can, without causing overstressing of the sensitive membrane material comes.

The memory according to the invention is characterized, as explained, by a prolonged service life, since gas losses by diffusion over the Separating membrane by the Gasnachfülleihrichtung in the form of the other Housing part 34 can be compensated. By the enlarged, Downstream gas volume leads to a lower pressure increase with nevertheless displaced oil volume as in other standard stores, The total memory, which is complemented as a unit, can be found in the Implementation of a modular kit with standard components and with only three housing parts and a connection seam is the hydraulic accumulator created with his workspaces. Through the on the actual memory attachable Gasnachfülleinrichtung a space-saving construction is achieved with few components waiving an elaborate, not tight to get Piping, which also the manufacturing and assembly costs as well reduces the maintenance of the solution according to the invention.

Claims (10)

Hydraulic accumulator, in particular diaphragm accumulator (12), comprising a storage housing (10), comprising at least one (12) or more, in particular two housing parts (32) and a separating element (14) located therein, in particular in the form of a separating membrane, which stores the accumulator housing (12). 10) into a gas space (20) and a fluid space (22), wherein the gas space (20) is gas-conductively connected to a gas refilling device via a connecting device, characterized in that the Gasnachfülleinrichtung is formed from at least one further housing part (34) is connected to the storage housing (10) to form a structural unit, and that the connecting means of at least one connecting opening (36) in the storage housing (10), which connects the interior (38) of the further housing part (34) with the gas space (20) , Hydraulic accumulator according to Claim 1, characterized in that the further housing part (34) comprises the outer peripheral side of a Cehäuseteii (12) of the storage housing (10), which limits the gas space (20). A hydraulic accumulator according to claim 1 or 2, characterized in that the other housing part (32) which delimits at least the fluid space (22) at its free, one housing part (12) facing edge forms a shoulder (42) on which the free End of the other housing part (34) can be placed. Hydraulic accumulator according to one of claims 1 to 3, characterized in that all three housing parts (12, 23, 34) are connected together at their front ends via a common connection point (46), preferably in the form of a weld seam. A hydraulic accumulator according to claim 4, characterized in that the separating element (14) is a separating membrane, preferably formed from an elastomeric material, which is held by a fastening ring (48) which leaves the connection point (46) on the inner circumference of the storage housing (10). Hydraulic accumulator according to claim 4 or 5, characterized in that the one housing part (12) which at least partially comprises the gas space (20), with a step-shaped shoulder (52) at its free fastening edge, the connection point (46) covers. Hydraulic accumulator according to one of claims 1 to 6, characterized in that the capacity of the further housing part (34) is twice as large as an output storage volume of the storage housing (10) on its gas side (20). Hydraulic accumulator according to one of claims 1 to 7, characterized in that the wall thickness of the further housing part (34) with respect to the wall thicknesses of the other two housing parts (12,32) of the storage housing (10) is reduced, in particular approximately half as strong. Hydraulic accumulator according to one of claims 1 to 8, characterized in that the separating element (14) is provided with a connection part (54) with which the fluid connection (40) of the accumulator housing (10) can be closed. Hydraulic accumulator according to one of claims 1 to 9, characterized in that all housing parts (12, 32, 34) are cylindrical in the region of their connection and have at their end sides at least partially curved end sides (56).

Images