SEPARATOR ELEMENT

Abstract

1. Separator element

2. A separator element consisting of at least two types of layers of plastic material, one type of which layers is media resistant to mineral oils; and the other type of which layers has low permeability to gases or is gas-tight,
wherein the two types of layers are firmly bonded to each other when in direct contact and form the elastically flexible separator element (12).

Claims

1. A separator element consisting of at least two types of layers of plastic material, one type of which layers (28) is media resistant to mineral oils; and the other type of which layers (30) has low permeability to gases or is gas-tight, wherein the two types of layers (28, 30) are firmly bonded to each other when in direct contact, resulting the elastically flexible separator element (12).

2. The separator element according to claim 1, characterized in that a layer (30) of the other type is accommodated between two layers (28) of the one type across the entire surface.

3. The separator element according to claim 1, characterized more than three layers (28, 30, 28) are bonded together in that in alternating sequence, wherein preferably the outermost layers (28) in the laminate are media resistant to mineral oils.

4. The separator element according to claim 1, characterized in that the layer (28) of one type is made of epichlorohydrin rubber and the layer (30) of the other type is made of isobutene-isoprene rubber.

5. The separator element according to claim 1, characterized in that the bonded types of layers (28, 30) form a shell body, preferably in the manner of a half shell (32).

6. The separator element according to claim 5, characterized in that there is a thickened rim (22) at the free end half-shell-shaped laminate formed by the layers (28) of one type, into which the free end of the layer (30) of the other type opens out.

7. A method of manufacturing a separator element according to claim 5, characterized in that the respective types of a layer (28, 30) are a sheeting; and in that the layers (28, 30) are bonded together by thermoforming to form the shell body.

8. The method of manufacturing a separator element according to claim 5, characterized in that the respective types of layer (28, 30) assumes the shape of the shell body as a partial body by means of thermoforming, and that subsequently the partial bodies are bonded to each other by vulcanization to form the shell body as a whole.

9. The method for producing a separator element according to claim 7, characterized in that the thermoforming, respectively the vulcanizing, is followed by a manufacturing step of annealing.

10. A hydraulic accumulator, in particular a diaphragm accumulator, in which a separator element (12) according to claim 1 is used to separate a fluid space (13), which can be filled with mineral oil, such as hydraulic oil, from a fluid space (14) filled with a process gas, such as nitrogen gas, and in that one type of layer (28) of the separator element (12) is arranged adjacent to the fluid space (13) holding the mineral oil in one accumulator housing (10).

11. A separator element consisting of at least two types of layers of plastic material, one type of which layers (28) is media resistant to mineral oils; and the other type of which layers (30) has low permeability to gases or is gas-tight, wherein the two types of layers (28, 30) are firmly bonded to each other when in direct contact, resulting the elastically flexible separator element (12), wherein the two outer layers (28) consist of one type of epichlorohydrin rubber and receive a layer (30) of the other type between them, characterized in that the layer (30) of the other kind between the two layers (28) of the one kind is made of isobutene-isoprene rubber; in that all layers (28, 30) consist of a single layer each; in that the respective type of layer (28, 30) is formed into the shape of a shell body as a partial body by means of thermoforming; and in that the three individual partial bodies are subsequently bonded together by vulcanization to form an overall shell body.

Description

[0035] Below, the separator element according to the invention is explained in more detail based on an exemplary embodiment according to the drawing. In the figures, in schematic representation, not to scale,

[0036] FIG. 1 shows the diaphragm accumulator with inserted separator element partly in view, partly in longitudinal section; and

[0037] FIG. 2 shows an enlarged view (5:1) of a section of the wall of a separator element of FIG. 1 labeled X.

[0038] FIG. 1 shows a pressure accumulator or hydraulic accumulator as a so-called diaphragm accumulator having an accumulator housing 10 in the form of a welded structure, in which a diaphragm 12 of multi-layer design separates a liquid side 13 from a gas side 14 as a movable separator element. A process gas, such as nitrogen gas, can be used to fill it via a filling port 16. The filling port 16 is covered by an end cap 18. On the fluid side 13 there is a fluid port 20 as a connection to a hydraulic system (not shown). In this respect, a hydraulic medium, such as mineral oil, reaches the fluid side 13 of the accumulator housing 10 from the side of the hydraulic system. In the central area of the diaphragm 12, on its end facing the fluid port 20, there may be a valve disk (not shown), which closes the fluid port 20 when the fluid side 13 is emptied and the diaphragm 12 is correspondingly extended. FIG. 1 shows the diaphragm 12 or the separator element in a position, in which a certain amount of liquid in the form of mineral oil is introduced onto the liquid side 13, thereby preloading the gas supply on the gas side 14 of the accumulator via the elastic diaphragm 12.

[0039] Pressure accumulators of this type, also in the form of so-called diaphragm accumulators, are state of the art and can be used in hydraulic systems as shock absorbers or pulsation dampers to dampen pressure surges in a hydraulic power circuit. Furthermore, they can be used as an energy source for a pumpless emergency circuit and are also suitable, for example, as hydraulic compression springs and the like in vehicles. Overall, hydraulic energy can be stored by preloading the gas supply on the gas side 14 of the accumulator.

[0040] The membrane 12 in the form of the separator element flares at its upper free end in a bulged rim 22. At this location of this bulged rim 22 the otherwise uniformly extending wall thickness of the accumulator housing 10 is provided with a wall recess with which the bulged rim 22 engages on the outer circumference, which bulged rim is held in this position by an inner circumferential metal clip 24, which is elastically flexible. In this way, the contact of the bulged rim 22 of the diaphragm 12 creates a fixed support 26 for the diaphragm 12 as a whole in the accumulator housing 10.

[0041] The diaphragm 12 as the separator element of the diaphragm accumulator is elastically flexible. An enlarged view of the laminate is shown in FIG. 2. In particular, according to the embodiment shown in FIG. 2, a three-layer laminate is implemented for the membrane 12, in which the two outer layers 28 form the one type that is resistant to mineral oils. The two layers 28 of the same thickness encase between them a layer 30 of the other type, which has low permeability to gases and is preferably completely gas-tight. In terms of wall thickness, this layer 30 is also approximately of the same thickness as the two rim layers 28 encasing the layer 30 to the outside.

[0042] The media-resistant layer 28 of one type is made of epichlorohydrin rubber, and the layer 30 of the other type is made of isobutene-isoprene rubber, which is to be regarded as gas-tight in this laminate shown in FIG. 2. The layers 28, 30 are firmly bonded together by vulcanization. Any stresses occurring between or in the laminate are eliminated by appropriate annealing. The shaping of the membrane 12 as a shell body can be achieved by thermoforming to form a kind of half shell 32. As further shown in FIG. 1, the bulged rim 22 formed from the outermost layers 28 is shaped as a receptacle, in which the upper free end of the middle layer 30 ends in such a way that the wall material of the bulged rim 22 still covers the free rim. It is particularly advantageous to select the specifications below for the different elastomer layers 28, 30: [0043] Hardness 50 to 70 Shore A; [0044] Elongation at break >400% (400% to 700%); [0045] Strength >10 N/mm.sup.2; and [0046] Temperature retraction <−10° C.

[0047] Owing to the use of different fluids at different temperatures and the requirements for flexibility, different demands are placed on the membrane materials, some of which are contradictory. For example, materials are used for low temperatures, but these usually have higher permeation values due to the required flexibility. Materials that achieve low-temperature flexibility with low permeation, on the other hand, may have problems with resistance to certain media and then cannot be used. By using two different materials (compounds), which are manufactured combined into one product, a highly flexible diaphragm 12 is created using ECO with good resistance to mineral oils and butyl with low gas permeability, which is media-resistant to mineral oils and, in the broadest sense, gas-tight to highly volatile process gases, such as nitrogen gas. This is without parallel in the prior art.