Expansion device

Abstract

The utility model relates to expansion equipment which is provided with an expansion shell (10), the expansion shell is provided with a separating membrane (12), the separating membrane divides the expansion shell (10) into two medium chambers (14 and 18), one medium chamber (14) can be filled with liquid through a liquid connector (16) in the expansion shell (10), and the expansion equipment is characterized in that even in the operation process of the equipment, the medium chamber (14) can be filled with liquid through the liquid connector (16). The other medium chamber (18) is also permanently connected to the surroundings (21) via at least one opening (20) in the expansion housing (10) such that an ambient pressure is present in the other medium chamber (18).

Description

Technical Field

[0001] The utility model relates to an expansion device. The expansion device is provided with an expansion shell. The expansion shell is provided with a separation membrane. The separation membrane divides the expansion shell into two medium chambers. One of the medium chambers can be filled with liquid via a liquid joint in the expansion shell. Background Art

[0002] DE 43 02 356 C2 discloses a safety assembly for installation in a cold water line connected to a pressure-resistant water heater, comprising an expansion vessel. The expansion vessel comprises a membrane and a pipe, on the inlet side of which a backflow preventer is provided, and downstream a safety valve is provided. The pipe is provided with a penetration, and the membrane of the expansion vessel is formed by a flexible hose, which is tensioned onto the pipe and surrounded by a pressure accumulator housing, which is filled with a gas, such as nitrogen, at a predetermined pressure via a connection.

[0003] EP 0 943 872 A2 discloses a combined domestic and heating water expansion vessel designed to accommodate volume changes caused by temperature fluctuations during operation of the associated systems. The expansion vessel is divided by an elastic membrane into a pressurized compressed gas chamber and a water chamber. The water chamber is connected to the water system via a connection. The domestic and heating water chambers are integrated into a common vessel. This results in a domestic water expansion vessel and a heating water expansion vessel that can be charged with different pressures. The domestic water expansion vessel consists of the actual domestic water chamber and a further compressed gas chamber that can be filled with compressed gas at a predefined pressure via a filling valve.

[0004] Because known expansion vessels are continuously exposed to the relevant operating pressure of the working gas contained in the respective closed chamber, they comply with the European Pressure Equipment Directive, which is implemented in Germany within the framework of the Pressure Equipment Ordinance. As soon as pressure vessels are operated at a maximum permissible pressure of 0.5 bar or more, they fall under the relevant regulations, which requires them to undergo internal or visual tests at certain intervals and, at longer intervals, at least strength tests (also called pressure tests). This is correspondingly time-consuming and costly, and monitoring periods must also be monitored to ensure their maintenance. Utility Model Content

[0005] Based on this prior art, the object of the present invention is to further improve the known solution in such a way that it no longer complies with the restrictive requirements of the Pressure Equipment Directive or the Pressure Vessel Ordinance with their legally prescribed inspection intervals.

[0006] An expansion device according to the invention achieves the corresponding object in its entirety. The invention is based on the recognition that for many applications, the corresponding expansion device only needs to compensate for the swing volume of the liquid in a more or less pressure-free manner, so that a high-pressure container with a closed gas volume at a predeterminable pressure, which is usually above the limit of 0.5 bar according to the Pressure Equipment Directive or the Pressure Vessel Ordinance, is not required.

[0007] The present invention therefore proposes an expansion device comprising an expansion housing with a separating membrane that divides the expansion housing into two media chambers. One of the media chambers can be filled with liquid via a liquid connection in the expansion housing. Even during operation of the device, the other media chamber is permanently connected to the surroundings via at least one opening in the expansion housing, such that ambient pressure prevails in the other media chamber. Liquid at a predeterminable pressure and volume can thus flow into one of the media chambers of the expansion housing. As a result, the elastic separating membrane bulges toward the other media chamber, and ambient air from the other media chamber is discharged through corresponding openings in the expansion housing. If the oscillation volume of the liquid is then withdrawn from one of the media chambers of the container, the membrane relaxes again and returns to its initial state. Air is then "re-sucked" into the other media chamber via corresponding ambient openings for compensation. The expansion device of the present invention can therefore be used for many applications in which a predeterminable oscillation volume must be compensated only on the liquid side, without having to comply with the strict regulations for containers subjected to a continuous operating pressure greater than 0.5 bar.

[0008] The expansion device according to the present invention is particularly suitable for connection to any type of fluid circuit, particularly a hydraulic circuit. In aircraft, due to the wide operating temperature range of +40°C to -56°C (ISA temperature), the hydraulic oil, which is essentially enclosed in the hydraulic working circuit, can expand or contract. The resulting oscillation volume in the hydraulic circuit can be reliably compensated for with minimal structural effort using the expansion device according to the present invention. This approach is therefore not available in the prior art.

[0009] In a preferred embodiment of the expansion device according to the invention, the liquid connection and the at least one opening for letting ambient air into the further medium chamber are arranged on opposite end faces of the expansion housing. This ensures a substantially predetermined vertical orientation of the expansion housing within its operating range, and the oscillation volume to be accommodated can freely enter and exit one of the medium chambers under the effect of gravity. The topmost arrangement of the air opening in the expansion housing achieves particularly favorable flow conditions for air entering and exiting the further medium chamber, the respective volume of which is predetermined by the expansion dimension of the elastic separating membrane, which in turn receives the oscillation volume on the liquid side.

[0010] In a particularly preferred embodiment of the expansion device according to the invention, the at least one opening in the expansion housing for the passage of air is used to accommodate an air filter. This allows the air volume flowing into the expansion housing to be cleaned of particulate contaminants. In a corresponding embodiment, the air filter can also separate moisture from the ambient air in a conventional manner.

[0011] In another particularly preferred embodiment of the expansion device according to the invention, the expansion housing is formed from two shell-shaped housing parts that are bonded together and made of a plastic material (e.g., a conventional composite material). Since the container-shaped expansion housing is not exposed to high pressure, in particular only to ambient pressure, a lightweight design made of plastic can be achieved.

[0012] In another preferred embodiment of the expansion device according to the invention, one of the housing parts with the corresponding opening overlaps the other housing part with the liquid connection, and a retaining ring is inserted in the overlapping region on the inner circumference of the other housing part with the liquid opening, which retaining ring presses the membrane into the annular recess of the other housing part. This achieves a sealed connection between the housing parts and, without additional fixing means, secures the membrane in a defined manner at the edges in the expansion housing by means of the retaining ring. Preferably, the one housing part with the opening protrudes inwardly in the region of the retaining ring and thus overlaps the other housing part and the retaining ring, which, combined with the shell-like design of the housing parts, still results in a pressure-stable design of the expansion housing.

[0013] In another preferred embodiment of the expansion device according to the invention, an axial play is provided between the other housing component with the retaining ring and the one housing component at the overlapping location. This provides tolerance compensation, making it possible to securely install the retaining ring with the membrane in the shell assembly of the housing components in any case.

[0014] The membrane is preferably formed from a shell-shaped elastomer having a closing element on its underside for closing the liquid connection when the other housing part is completely drained on the liquid side of the liquid connection. This allows the membrane to easily move into its closed position and allow the other housing part to be completely drained of liquid.

[0015] In a preferred embodiment of the expansion device according to the invention, it is further provided that the separating membrane has a ridge-like thickening which engages with a radially protruding lip into an associated annular gap in the other housing part. This provides an additional possibility for fixing the edge-side end of the membrane in the other housing part.

[0016] In another preferred embodiment of the expansion device according to the invention, the liquid connection in the other housing part has two connection parts, which pass through the liquid connection and clamp the other housing part fixedly relative to one another at the edge region of the liquid connection between the two connection parts. In this way, the other housing part, which may be reinforced with glass fibers, is reliably passed through by the metal material of the connection parts, so that despite the lightweight design of the housing itself, a secure connection of the hydraulic circuit with its standardized connection geometry is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The expansion device according to the present invention will be explained in detail below using an embodiment according to the drawings.

[0018] Figure 1 The main components of the expansion device are shown in longitudinal section. DETAILED DESCRIPTION

[0019] according to Figure 1 The expansion device has an expansion housing 10 with a partition wall in the form of an elastic partition membrane 12 arranged therein. The partition membrane 12 divides the housing 10 in its interior into a medium chamber 14, which can be filled with a liquid, for example in the form of hydraulic oil, via a liquid connection 16. Via the corresponding liquid connection 16 (which is connected in a conventional manner to a hydraulic supply (not shown in detail), the liquid can also be discharged from the medium chamber 14 when necessary. Figure 1 As seen from the direction of view, a further second medium chamber 18 is provided above the separating membrane 12 , which is permanently connected to the surroundings 21 via an opening 20 in the expansion housing 10 even during operation of the device, so that ambient pressure prevails in the relevant further medium chamber 18.

[0020] If also from Figure 1As a result, the liquid connection 16 and the opening 20 for the passage of ambient air into the further medium chamber 18 are arranged on opposite end faces of the expansion housing 10 , specifically coaxially with respect to a longitudinal axis 22 of the expansion housing 10 .

[0021] In a preferred embodiment of the expansion device according to the present invention, Figure 1 The illustration further provides that an opening 20 for the passage of air in the expansion housing 10 serves to accommodate an air filter 24, which is screwably received in the form of a replacement element in the opening 20. If the air filter 24 becomes clogged with particulate matter from the ambient air, this air filter can be easily replaced by a new air filter 24.

[0022] The expansion housing 10 is essentially composed of two shell-shaped housing parts 26, 28, which are bonded to one another along a predeterminable bonding section 30 and are made of a plastic material, preferably a glass-fiber-reinforced plastic. However, it is also entirely possible to manufacture the housing parts 26, 28 from aluminum die-castings, etc. Instead of the described bonding via the bonding section 30, other connections can also be provided. For example, in an embodiment not shown in detail, the two housing parts 26, 28 can be screwed to one another.

[0023] The upper housing part 26 with the opening 20 overlaps the other housing part 24 with the liquid connection 16 along a protruding edge 32, and in the area of this overlap, a retaining ring 36 is inserted on the inner circumference 34 of the other housing part 28 with the liquid connection 16, which retaining ring presses the separating membrane 12 into the annular recess 38 of the other housing part 28. At the overlapping point, an axial gap exists between the other housing part 28 with the retaining ring 36 and the one housing part 26, as viewed in the longitudinal orientation of the longitudinal axis 22. The retaining ring 36 rests on the protruding contact surface 42 of the other housing part 28. Figure 1 The annular recess 38 is located below the annular contact surface 42 , and above it the contact surface 42 extends into an outwardly widening cone 44 , the upper end-side boundary walls of which together delimit the gap 40 when viewed horizontally downward.

[0024] The separating membrane 12 is formed from a shell-shaped elastomer having a closing element 46 on its bottom side, which serves to close the liquid connection 16 on the liquid side of the separating membrane, or on the side of one of the media chambers 14, when the housing part 28 is completely empty. The closing element 46 is designed in the manner of a solid valve disk and is molded, in particular "snapped," into the lower end of the membrane body of the separating membrane 12. The disk-shaped closing element 46 is arranged concentrically with the longitudinal axis 22, and its circumferential diameter is selected at least so that a downwardly projecting closing edge, flush with the free end face of the separating membrane 12, comes into contact with a free circumferential edge 50 that delimits the liquid connection 16 on the opposite inner side of the other housing part 28.

[0025] Furthermore, the separating membrane 12 has a ridge-like thickening 52 at its outer free end. This thickening is surrounded outwardly by the annular recess 38 and inwardly, toward the longitudinal axis 22, by a concave recess 54 in the retaining ring 36. The retaining ring 36 is preferably designed as a resiliently yielding plastic clip that can be inserted from above through a free opening in the other housing part 28 and latched to the other housing part via the thickening 52 along the contact surface 42. Due to the elastic preload, the retaining ring 36 forms a retaining clip for the thickening 52 of the separating membrane 12. To securely fix the separating membrane 12 in the other housing part 28, the thickening 52 further comprises a radially protruding, thin-walled lip 56 at its upper end, which engages flush with an associated annular gap 58 in the other housing part 28. This ensures secure anchoring of the separating membrane 12 in the other housing part 28, even when viewed in the axial direction parallel to the longitudinal axis 22.

[0026] If also from Figure 1As can be seen, the liquid connection 16 in the other housing part 28 has two connection parts 60 and 62, which pass through the liquid connection 16 and clamp the other housing part 28 fixedly relative to each other between them at the edge region 64 of the liquid connection 16. One connection part 60 has an external thread 65 (not shown in detail) on its free end, via which the expansion device can be connected to a hydraulic supply circuit (not shown) as a whole with the expansion housing 10 in a conventional manner. On the outer circumference, one connection part 60 has an O-ring 66 for sealing any leakage from the first media chamber 14 to the surrounding environment 21. The O-ring 66 rests sealingly on the inner circumference of the edge region 64 of the other housing part 28. Once the media chamber 14 is completely drained of liquid, the other connection part 62 is first inserted from the inside. Its free upper end is formed as a flat contact surface 67 transverse to the longitudinal axis 22 for contact of the closure part 46. The connecting part 62 has an external thread 68 along a cylindrical, hollow engagement socket, via which the hollow cylindrical connecting part 60 can be screwed from the outside with a correspondingly configured internal thread section onto the connecting part 62. If the two connecting parts 60, 62 are thus fixed to one another at the given thread section, the edge region 64 is clamped between the connecting parts 60, 62. For this purpose, the connecting part 62 has a flange-like widening 69 in the direction of the closing part 46, the outer diameter of which corresponds to the outer diameter of the edge 48 of the closing part 46.

[0027] In addition to or as an alternative to the adhesive section 30, the upper housing part 26 can also be designed as a clip part with a widened outer edge 70 and clipped onto the lower housing part 28. This creates a housing structure that is simple and cost-effective to manufacture and that dispenses with conventional connection techniques such as adhesive bonding, screwing, etc., for connecting the housing parts 26, 28 to one another. A clip or snap connection can be implemented, since only ambient pressure prevails in the other media chamber 18 via the opening 20 or the air filter 24. In any case, viewed in a horizontal plane, the free edge of the outer wall 70 protrudes beyond the lower end face of the retaining ring 36. To exert the necessary retaining force, the circumferential outer wall 70 widens in diameter toward its free end.

Claims

1. An expansion device comprising an expansion housing (10), the expansion housing comprising a separating membrane (12), the separating membrane dividing the expansion housing (10) into two media chambers, one of the media chambers (14) being fillable with liquid via a liquid connection (16) in the expansion housing (10), characterized in that Even during operation of the device, the further medium chamber (18) is permanently connected to the surroundings (21) via at least one opening (20) in the expansion housing (10), so that ambient pressure prevails in the further medium chamber (18).

2. The expansion device according to claim 1, characterized in that The liquid connection (16) and the at least one opening (20) for letting ambient air into the further medium chamber (18) are arranged on opposite end sides of the expansion housing (10).

3. The expansion device according to claim 1 or 2, characterized in that The at least one opening (20) in the expansion housing (10) for the passage of air is used to accommodate an air filter (24).

4. The expansion device according to claim 1 or 2, characterized in that The expansion housing (10) is composed of two shell-shaped housing parts which are bonded to each other and made of plastic material.

5. The expansion device according to claim 4, characterized in that One of the housing parts (26) having the corresponding opening (20) overlaps the other housing part (28) having the liquid connection (16), and a retaining ring (36) is inserted in the overlapping region on the inner circumference (34) of the other housing part (28) having the liquid connection (16), which retaining ring presses the separating membrane (12) into the annular recess (38) of the other housing part (28).

6. The expansion device according to claim 5, characterized in that The one housing part (26) having the opening (20) protrudes inwardly in the region of the retaining ring (36) and overlaps the other housing part (28) and the retaining ring (36).

7. An expansion device according to claim 5 or 6, characterized in that At the overlapping location, an axial gap (40) exists between the other housing part (28) having the retaining ring (36) and the one housing part (26), and the other housing part (28) rests on the retaining ring (36) having a protruding contact surface (42).

8. The expansion device according to claim 5 or 6, characterized in that The separating membrane (12) is formed from a shell-shaped elastomer which has a closing element (46) on the bottom side for closing the liquid connection (16) when the other housing part (28) on the liquid side of the separating membrane is completely empty.

9. The expansion device according to claim 5 or 6, characterized in that The separating membrane (12) has a ridge-like thickening (52) which engages with a radially protruding lip (56) in an associated annular gap (58) in the other housing part (28).

10. The expansion device according to claim 5 or 6, characterized in that The liquid connection (16) in the other housing part (28) has two connection parts (60, 62) which pass through the liquid connection (16) and clamp the other housing part (28) between the two connection parts in a fixed manner relative to each other at an edge region (64) of the liquid connection (16).

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