EP2588762B1 - Pressure store and insert part for a pressure store - Google Patents

Description

The invention relates to a pressure accumulator comprising a housing, a arranged between the housing and a flexible separation membrane first subspace, arranged between the separation membrane and a support body second subspace, and adjacent to the second subspace, the closure of the housing forming the head part, wherein the first Partial space with a first fluid and the second subspace with a second fluid can be filled, wherein the first and the second subspace vary by movements of the separation membrane depending on the respective filling state in their respective size, and wherein on the head part, a holding body is provided on which the Opening edge of the separation membrane is anchored.

Such an accumulator is off DE 101 13 415 A1 known. In the known pressure accumulator in the form of a hydropneumatic pressure accumulator, a flexible separating element is arranged in a storage housing, formed by a pipe end piece, and surrounds a support body having fluid passages. The support body has at least sections on a non-circular cross-sectional shape. The separating element is anchored to form a seal on the storage housing so that each separate receiving spaces are formed on the outside and inside of the separating element. A centrally located, through bore forms a passage leading to the internal receiving space of the storage for a storage medium. For filling the outside gas space, a gas valve is provided. The known pressure accumulator can be used for energy storage, for example in conjunction with vehicle suspensions, or as a pulsation damper. Furthermore, the known solution is particularly suitable for damping pressure peaks in hydraulic or other fluid power systems. For use as an accumulator for storage media in the form of chemically aggressive fluids, such as urea-water solution, the known solution leaves nothing to be desired.

Another accumulator is off DE 38 10 509 C2 known. A pressure accumulator is known, comprising a container main body with an outer tube of cylindrical shape, at one end of a side plate and at the other end a lid is arranged, at least one inlet opening and an outlet opening, which are formed on the outer tube, and a bladder or A membrane for dividing the interior of the container main body into a gas chamber and a liquid chamber, wherein an opening of the bubble is sealed by the lid. An insert is arranged to project into the bladder for the purpose of reducing the volume of the gas chamber. The insert is formed of a foot part, a middle part and a head part, wherein the head part is kept in contact with the bottom of the membrane, which makes it possible to prevent damage to the membrane by repeated contraction. In the contracted state, the bladder or membrane rests against the insert.

The GB 877,800 A describes a device for damping pressure pulses in fluid lines with a spherical housing, in which a flexible separation membrane between a first subspace and a second subspace is arranged. In the first subspace is the fluid to be damped. The first subspace is between the housing and the Separating membrane arranged. The second compartment is located between the separation membrane and a spherical support body. The second compartment enclosed by the separation membrane is filled with a pressurized gas. The housing is formed in two parts and has a head part, on which a holding body is arranged, on which an opening edge of the separating membrane can be anchored. For this purpose, the head part on a connectable to the housing cover part with inner wall parts in the form of a concentric to the axis of the housing spherical cap.

Pressure accumulators of this type are widely used in various sizes and structural designs to receive and deliver varying volumes of subject fluids that are under the operating pressure of a fluid system connected to the fluid side, with the bladder on its gas side under a biasing pressure of the working gas forming a pressure pad , The reliability of the pressure accumulator depends primarily on the usually made of a plastic material, especially butyl, existing from memory bladder, which is not only exposed to mechanical stresses in operation, but should also be resistant to chemically aggressive storage fluids. As has been shown, it is not yet possible in connection with aggressive fluids, such as urea-water solutions, to ensure a trouble-free life of sufficient length during continuous operation, for example over 20,000 hours.

The so-called "urea injection" is increasingly being used in automotive engineering to reduce nitrogen oxide (NOx) emissions by injecting it into the exhaust gas stream from internal combustion engines. In such an application, it is particularly important that a long service life in continuous operation is achievable trouble-free.

In this regard, the invention has the object to provide a pressure accumulator available, which is characterized in particular in connection with aggressive storage media by improved reliability and ease of installation.

According to the invention this object is achieved by a pressure accumulator having the features of claim 1 in its entirety.

According to the characterizing part of claim 1, a significant feature of the invention is that within the cover part of the holding body is arranged such that between the outer wall in the form of spherical surface parts and the inner wall parts of the lid part, a gap for receiving a bordering on the edge of the opening edge region Separating membrane is formed.

The housing typically has a head part which adjoins the second subspace and forms the closure of the housing. The housing is expediently cup-shaped, wherein the first compartment is arranged on the bottom side. In the head part, a connection device for the second fluid can be provided.

A particularly secure anchoring of the separating membrane can be achieved if the holding body has, in an axially offset from its holding part in the direction of the connection means a machined into the outer wall annular groove in the anchoring of the separation membrane engages a peripheral edge surrounding the edge bead.

In particularly advantageous embodiments, the connection device has a screw socket, which engages through an opening concentric to the central axis of the cover part and the by screwing with the cover part, the holding body against the inner wall of the cover part pulls and clamped the located in the gap edge region of the separation membrane.

The invention further comprises an insert part for a pressure accumulator comprising a head part forming the closure of a housing, on which a holding body for anchoring the opening edge of a separating membrane is provided, and a supporting body for abutment of the separating membrane, wherein the holding body forms a holding part, on which the Support body is arranged, which is characterized in that the holding body in the region of the holding part forms a circular cylinder, at the edge region of which one or more latching elements are formed, which form with mating elements on the support body an anchoring this snap connection.

According to the invention, the arrangement is made such that the holding body forms a circular cylinder in the region of the holding part, on the edge region of which one or more catch elements are formed which form a snap-in connection anchoring this with counter-elements on the supporting body. This type of anchoring of the support body is particularly easy to install and allows low production costs.

Advantageous embodiments of the insert part according to the invention are objects of the corresponding dependent claims.

The locking elements can be offset from the end edge of the outer wall of the holding part and formed by depressions of the outer wall of the holding part, in which a bead-like, radially inwardly projecting projection on the inside of the support body can be snapped.

Alternatively, the locking elements on the inner wall of the holding member by an axially remote from the end edge recess and a radially inside projecting, be formed adjacent to the end edge projection which can be latched with counter-elements of distributed over the circumference of the opening of the support body locking fingers. In a ring of individual detent fingers thus formed, the assembly is particularly simple and convenient. The same applies to embodiments in which the latching takes place on the outside of the holding part. Also in this case, individual locking fingers may be provided at the end edge of the support body.

In a particular embodiment, the pressure accumulator according to the invention comprises a housing, an insert part inserted into the housing, a first subspace arranged between the housing and a flexible separation membrane, and a second subspace arranged between the separation membrane and the support body, wherein the head part adjoins the second part Partial space adjacent, wherein on the holding body, the opening edge of the separation membrane is anchored, wherein the first subspace with a first fluid and the second subspace is filled with a second fluid, and wherein the first and the second subspace by movements of the separation membrane depending on the respective filling state in vary in size.

In particularly advantageous embodiments of the support body has the shape of a rotating body, which is rounded at the end facing the first compartment and formed closed and provided with at least one lateral wall opening as a passage point between the second and third compartment. In such a design, the support body for the separation membrane or storage bubble can form a large-area support, so that the memory bubble which is practically free of creases when the pressure is exceeded is optimally protected.

In a particular embodiment of the pressure accumulator according to the invention, the holding body has the shape of a bell whose bell casing surrounds a fourth subspace adjoining the third subspace. In this way, the absorption capacity of the pressure accumulator for the second fluid or the typically gaseous working medium is increased and at the same time reduces the material requirement for the formation of the pressure accumulator.

The support body is preferably formed from a plastic material. With particular advantage this glass fiber-reinforced polyarylamide IXEF ^®, a material, which is distinguished over conventional glass fiber reinforced plastics by a smooth, closed outer skin can be provided. Because of these properties, the holding body and / or the connection device can be formed from this material in an advantageous manner.

Advantageously, the pressure accumulator is designed as a hydropneumatic bladder accumulator for a gaseous second fluid as a working medium and / or a liquid first fluid as a storage medium. Particularly preferably, the pressure accumulator for filling a storage medium in the form of a chemically aggressive fluid, such as urea-water solution is formed. This allows use of the pressure accumulator according to the invention in the urea injection, especially in the automotive field.

Fig. 1

einen gegenüber einer praktischen Ausführungsform lediglich geringfügig vergrößert dargestellten Längsschnitt eines Ausführungsbeispieles des erfindungsgemäßen Druckspeichers;

Fig. 2

einen Längsschnitt eines erfindungsgemäßen Einsatzteils umfassend einen Haltekörper mit daran festgelegtem Stützkörper;

Fig. 3

einen gegenüber Fig. 2 stark vergrößerten Ausschnitt des in Fig. 2 mit III bezeichneten Bezirks; und

Fig. 4

einen der Fig. 2 ähnlichen Längsschnitt, in dem ein abgewandeltes Beispiel der erfindungsgemäßen Verrastung des Stützkörpers am Haltekörper dargestellt ist.

The invention is explained in detail below with reference to the drawing. Show it:

Fig. 1

a comparison with a practical embodiment only slightly enlarged illustrated longitudinal section of an embodiment of the pressure accumulator according to the invention;

Fig. 2

a longitudinal section of an insert part according to the invention comprising a holding body with fixed thereto supporting body;

Fig. 3

one opposite Fig. 2 greatly enlarged section of the in Fig. 2 District designated III; and

Fig. 4

one of the Fig. 2 similar longitudinal section, in which a modified example of the latching of the support body according to the invention is shown on the holding body.

The invention will be explained below with reference to the example of the use of the pressure accumulator for a system of urea injection. In Fig. 1 , which shows the embodiment of the pressure accumulator in its entirety, a memory housing is denoted by 2, which has the shape of a large cylindrical pot on the closed bottom 4, a flow opening 6 is located on the whole. The aligned on the central longitudinal axis 10 opening 6 allows the supply and removal of a first fluid, such as a urea-water solution, to or from the first compartment 8, which is located in the housing 2 adjacent to the bottom 4. A head part 12 which can be screwed to the storage housing 2 forms the fluid-tight closure of the upper, open end of the housing 2.

The head part 12 has an outer cover part 14 on which the screw connection with the housing 2 is formed and which may consist of a metallic material, for example of aluminum, as may also be the case with the housing 2. Alternatively, the cover part 14 may also be formed from a structurally stable plastic material. The cover part 14 has a central, concentric with the axis 10 opening 16. At a small distance from the opening 16, the cover part 14 inner wall parts in the form of a concentric to the axis 10 spherical cap 18. Within the cover part 14, the head part 12 has a holding body 20, with a integral therewith, the connecting device for the second fluid-forming screw socket 22, which passes through the opening 16 of the cover part 14 and is fixed by means of which in Zusammenwirküng with a nut 24 of the holding body 20 within the cover part 14. Through the screw neck 22, a central fluid channel 26 extends to fill a third subspace 28 with the working medium under bias pressure as the second fluid. A located within the channel 26 valve insert is not shown in the drawing.

The holding body 20 has the shape of a bell whose shell surrounds a fourth sub-space 30 which adjoins the third sub-space 28. The bell shell forms on its outer wall spherical surface parts 34 which define a clamping gap 36 for the anchoring region 38 located in the gap 36 of a separation membrane 40 between itself and the cap 18 of the cover part. The bladder formed from a plastic suitable for such pressure accumulators, such as butyl, forms the flexible separating membrane 40 between the first subspace 28 and the second subspace 54. The holding body 20 has an annular groove 42 between the end of the outer spherical surface part 34 and the screw neck 22, into which for particularly secure anchoring of the separation membrane 40 engages an edge rim 44 surrounding its opening edge.

The holder body 20 forms with which located within the plane formed by the separating membrane 40 bubble cap, a holding portion 46 for anchorage of a projecting into the interior of the bladder support body 48. This is formed of a sufficiently structurally rigid plastic material, with glass fiber-reinforced polyarylamide IXEF ^® to be particularly well has proved suitable. How out Fig. 1 can be seen, the support body 48 has the shape of a body of revolution with spherical rounded, closed, located at a distance from the bottom 4 of the housing 2 lower end and surrounds adjacent to the fourth subspace 30 third subspace 28. The other, upper end 50 of the support body 48 is fixed to the holding part 46 by means of a snap connection. As Fig. 1 In addition, the support body 48 is approximately V-shaped in longitudinal section and has lateral wall openings 52 for the passage of the working fluid to the second compartment 54, which adjoins the third compartment 28.

The details of the insert for a pressure accumulator are the clearest FIGS. 2 and 3 removable. As can be seen 46 recesses 56 and 60 are formed at a small distance from the end edge 56 of the holding member, in which the end portion of the support body 48 is receivable, wherein a radially inwardly projecting projection 62 of the support body 48 can be snapped into the recess 60. The holding body 20 is formed in the present example, as well as the support body 48 and located in the channel 26 of the nozzle 22 valve made of glass fiber reinforced polyarylamide IXEF ^® , so that the insert part comprising the holding body 20 with the support body 48 fixed thereto a completely made of plastic unit forms.

In operation, when used for the urea injection, the first subspace 8 of the pressure accumulator is filled by means of a pump with the urea-water solution until an upper value of the system pressure is reached and the pump shuts off. The accumulator pressure forces the metered injection storage medium into the system. When a lower pressure value is reached, the pump switches on again. If it should come to unwanted pressure excesses and a certain limit of the volume increase of the first subspace 8 is exceeded, the separation membrane 40 applies to the support body 48 and is thereby protected against overloading and damage.

The Fig. 4 shows a variant of the design of the insert part, wherein the locking elements now on the inner wall of the holding part 46 of the holding body 20 are arranged. As Fig. 4 shows, it is a recess 64 axially remote from the end edge 56 and a radially inwardly projecting, adjoining the end edge 56 projection 66. The counter-elements on the part of the support body 48 are formed by retaining fingers 68 which extend beyond the circumference of the opening Support body 48 are arranged distributed. When formed by individual locking fingers 68 counter elements, the preparation of the locking designed particularly simple and convenient.

Also at the in FIGS. 2 and 3 shown embodiment of the latching on the outside of the holding member 46 of the holding body 20, the counter-elements of the support body 48 may also be formed of individual, circumferentially distributed locking fingers.

Claims (15)

1. A pressure accumulator comprising

   - a housing (2),

   - a first compartment (8) disposed between the housing (2) and a flexible separating diaphragm (40),

   - a second compartment (54) disposed between the separating diaphragm (40) and a support body (48), and

   - a head part (12) which forms the closure of the housing (2) and which borders the second compartment (54),

   the first compartment (8) being fillable with a first fluid and the second compartment (54) being fillable with a second fluid,
   the first and the second compartment (8, 54) varying in their respective size as a result of movements of the separating diaphragm (40) as a function of the respective filling state, and
   there being provided on the head part (12) a retaining body (20) to which the opening edge of the separating diaphragm (40) can be anchored,
   and the head part (12) having a cover part (14) that can be connected to the housing (2) and with inside wall parts in the form of a spherical cap (18) which is concentric to the axis (10) of the housing (2), characterised in that within the cover part (14) the retaining body (20) is arranged such that between its outside wall in the form of spherical surface parts (34) and the inside wall parts of the cover part (14) a gap (36) is formed for accommodating an edge region (38) of the separating diaphragm (40) which borders the opening edge.
2. The pressure accumulator according to Claim 1, characterised in that a connection device (22) is provided for the second fluid in the head part (12).
3. The pressure accumulator according to Claim 2, characterised in that the retaining body (20) in a region which is axially offset from its retaining part (46) in the direction of the connection device (22) has an annular groove (42) which has been machined into the outside wall and in which an edge bead (44) which surrounds the opening edge of the separating diaphragm engages for the anchoring of the separating diaphragm (40).
4. The pressure accumulator according to Claim 2 or 3, characterised in that the connection device has a screw fitting (22) which extends through an opening (16) of the cover part (14) which is concentric to the central axis (10), which fitting pulls the retaining body (20) against the inside wall of the cover part (14) by screwing to the cover part (14) and clamps the edge region (38) of the separating diaphragm (40) located in the gap (36).
5. An insert part for a pressure accumulator, comprising

   - a head part (12) which forms the closure of a housing (2) and on which a retaining body (20) is provided for anchoring the opening edge of a separating diaphragm (40), and

   - a support body (48) for supporting the separating diaphragm (40),

   the retaining body (20) forming a retaining part (46) on which the support body (48) is arranged,
   and the retaining body (20) forming a circular cylinder in the region of the retaining part (46),
   characterised in that there are formed on an edge region of the circular cylinder one or more catch elements (58, 60) which with counter-elements (62) on the support body (48) form a snap connection which anchors the latter.
6. An insert part according to Claim 5, characterised in that the catch elements on the outer wall of the retaining part (46) are offset from its end edge (56) and are formed by depressions (58, 60) of the outer wall of the retaining part (46) into which a bead-like projection (62) which protrudes radially to the inside can be snapped on the inside of the support body (48).
7. The insert part according to Claim 5, characterised in that the catch elements on the inside wall of the retaining part (46) are formed by a depression (64) which is axially spaced apart from its end edge (56) and a projection (66) which adjoins the end edge (56) and protrudes radially to the inside, and said catch elements can be latched to counter-elements in the form of catch fingers (68) which are distributed over the periphery of the opening of the support body (48).
8. The insert part according to any of Claims 5 to 7, characterised in that the support body (48) is formed from plastic, preferably from glass fibre-reinforced polyarylamide IXEF^®.
9. A pressure accumulator comprising

   - a housing (2),

   - an insert part inserted into the housing (2) according to any of Claims 5 to 8,

   - a first compartment (8) disposed between the housing (2) and a flexible separating diaphragm (40), and

   - a second compartment (54) disposed between the separating diaphragm (40) and the support body (48),

   the head part (12) bordering the second compartment (54),
   the opening edge of the separating diaphragm (40) being anchored to the retaining body (20),
   the first compartment (8) being fillable with a first fluid and the second compartment (54) being fillable with a second fluid,
   the first and the second compartment (8, 54) varying in their respective size as a result of movements of the separating diaphragm (40) as a function of the respective filling state.
10. The pressure accumulator according to any of Claims 1 to 4 and/or 9, characterised in that the support body (48) comprises a third compartment (28) connected to the second compartment (54) such as to convey fluid.
11. The pressure accumulator according to Claim 10, characterised in that the support body (48) is a body of revolution which is made rounded and closed on the end facing the first compartment (8) and is provided with at least one wall opening (52) as a passage site between the second compartment (54) and the third compartment (28).
12. The pressure accumulator according to Claim 10 or 11, characterised in that the retaining body (20) has the shape of a bell the jacket of which surrounds a fourth compartment (30) which borders the third compartment (28).
13. The pressure accumulator according to any of Claims 1 to 4, 9 to 12, characterised in that the retaining body (20) and/or the connection device (22) is formed from plastic, in particular from glass fibre-reinforced polyarylamide IXEF^®.
14. The pressure accumulator according to Claim 1 to 4, 9 to 13, characterised in that the pressure accumulator is made as a hydropneumatic bladder accumulator for a gaseous second fluid as a working medium and/or a liquid first fluid as a storage medium.
15. The pressure accumulator according to any of Claims 1 to 4, 9 to 14, characterised in that the pressure accumulator is made for filling with a storage medium in the form of a chemically corrosive first fluid such as a urea-water solution.

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