Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
  • F15B1/02—Installations or systems with accumulators
  • F15B1/04—Accumulators
  • F15B1/08—Accumulators using a gas cushion; Gas charging devices; Indicators or floats therefor
  • F15B1/10—Accumulators using a gas cushion; Gas charging devices; Indicators or floats therefor with flexible separating means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2201/00—Accumulators
  • F15B2201/30—Accumulator separating means
  • F15B2201/315—Accumulator separating means having flexible separating means
  • F15B2201/3151—Accumulator separating means having flexible separating means the flexible separating means being diaphragms or membranes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2201/00—Accumulators
  • F15B2201/30—Accumulator separating means
  • F15B2201/315—Accumulator separating means having flexible separating means
  • F15B2201/3153—Accumulator separating means having flexible separating means the flexible separating means being bellows
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2201/00—Accumulators
  • F15B2201/30—Accumulator separating means
  • F15B2201/315—Accumulator separating means having flexible separating means
  • F15B2201/3155—Accumulator separating means having flexible separating means characterised by the material of the flexible separating means

Definitions

• Pressure vessel in particular hydraulic accumulator
• the invention relates to a pressure vessel, in particular to a hydraulic accumulator, with a space in the container for a first, in particular gaseous, working medium of a space for a second working medium, in particular a fluid, separating, compliant and deformable movable separating element, which defines a domed major separation surface emanating from an annular rim.
• a pressure vessel of this kind in the form of a hydraulic accumulator is disclosed in DE 28 52 912 A1.
• the resilient separating element which in the known hydraulic accumulator consists of a rubber-like material (synthetic rubber, such as acrylonitrile-butadiene rubber) forms a deformable by deformation membrane which separates a gas side in the storage housing from a liquid side.
• impermeability of the membrane must be ensured in order to avoid gas diffusion.
• corresponding mechanical properties of the membrane are required, in particular easy mobility and high bending fatigue strength, which are also retained under the influence of aggressive media.
• known hydraulic accumulator these demands are only partially fulfilled.
• the invention has the object to provide a pressure vessel, in particular hydraulic accumulator available, which in contrast is characterized by a significantly improved performance.
• a separator is provided vorge- which is made of a material having a fluorine plastic material or preferably consists entirely of fluorine plastic material, on the one hand, an excellent diffusion tightness is ensured, while on the other hand, a separator is available , which has the optimum mechanical properties for use as a diaphragm in hydraulic accumulators, such as extreme fatigue strength. It can therefore be used very small wall thicknesses, resulting in the desired ease of mobility of the membrane. Due to the resulting good response of the pressure vessel is therefore particularly suitable for use as a pulsation damper.
• a particularly suitable material is polytretafluoroethylene.
• Polytetrafluoroethylene is not plastically moldable because of its very high melt viscosity, and the particular desired shaped body of this material is cold pressed from powdered raw material with 200 to 400 bar and sintered at 370 ° to 380 ° without pressure. If you want to receive films, they are regularly peeled off from cylindrical solid blocks. Accordingly, polytetrafluoroethylene is regularly marketed in the form of rigid solids such as plates, rods, tubes, etc. It is surprising to one of ordinary skill in the membrane art that he can nevertheless obtain parting elements made wholly or partly of polytetrafluoroethylene material, which have such a high mobility that they can even take over the function of a flexible rolling diaphragm.
• the pressure vessel according to the invention is also suitable for use in the presence of chemically aggressive media.
• the separating element defines a curved main separating surface, on whose inner side relative to the curvature ring-bead-like elevations are formed protruding.
• the vertexes of the annular bead-like elevations have a circular curvature, so that notch effects are avoided.
• the annular bead-like elevations are formed by folding, which are open on the outer side and here form annular groove-like depressions in the main separation surface.
• the height of the folds in the case of a membrane formed in this way, as is the case with a bellows, a particularly large length of the material web is available, which can be moved in order to roll or extend the membrane.
• the arrangement here is such that the height measured from the open end to the apex of the folds along their vertical axis is different from at least one fold with respect to the height of other folds.
• the wall section extending from the annular edge to the nearest first fold has a wall thickness which has the largest value at the annular edge and drops to the first fold towards the value of the wall thickness of the wall sections between the folds.
• the edge thickening thus formed favors, without impairing the flexibility of the remaining membrane, the clamping of the membrane on the associated housing element of the pressure vessel and the formation of a sealing connection at the clamping point.
• FIG. 1 shows a broken and slightly schematically drawn longitudinal section of an embodiment of the pressure vessel according to the invention in the form of a hydraulic accumulator, wherein only the region of the lower housing part and an adjacent part of the upper housing part can be seen;
• FIG. 1 enlarged and half-side drawn longitudinal section of only designed as a rolling diaphragm separating element of the embodiment of FIG. 1 and
• FIG. 3 is a comparison with FIG. 2 further enlarged partial view of the marked in Fig. 2 with III area.
• a lower housing part 3 with a concentric to the housing longitudinal axis 7, bottom-side fluid port 9 and an adjacent to the lower housing part 3 portion of the upper housing part 5 are shown.
• annular edge 13 clamped a separating element in the form of a designated as a whole with 1 rolling diaphragm.
• an edge thickening 21 of the rolling diaphragm 1 is supported, on the one hand, on an annular surface 22 of the lower housing part 3 and, on the other hand, abuts an O-ring 15, which in turn sits in an annular groove 20 on an axially projecting annular body 14 of the upper housing part 5.
• FIG. 1 and 2 show the rolling diaphragm 1 in a fully unrolled or extended state, in which the space 11 in FIG. 1 above the membrane 1, the gas side of the hydraulic accumulator, has the largest volume and there is no fluid pressure at the fluid connection 9 , so that the membrane 1 rests against the inner wall of the housing lower part 3, wherein a central reinforcing bead 29 of the membrane 1 engages over the edge of the fluid connection 9 and thus provides a mechanical safeguard against pressing the membrane 1 into the fluid connection 9 in the absence of Fluid pressure forms.
• the wall thickness in such a way that the wall thickness decreases to the first fold 17, namely to the thickness value of flat wall portions 23, which are respectively between the folds 17 and 19.
• the wall thickness drops from the thickening 21 to the first fold 17 from a value of 1.2 mm to the value of 0.5 mm, which occurs at the successive wall sections 23 between the folds 17 and 19 is given in each case.
• the edge thickening 21 on the inside forms a kind of shell shape, which forms a partial enclosure of the O-ring 15 (not shown in FIG. 2).
• the fold height measured along the vertical axis 25 is smaller in the first fold 17 than in the subsequent folds 19, which each have the same height, with all the folds 17 and 19 being circular at their apex are.
• the folds 17 and 19 are open on the outer side with respect to the curvature, so that annular groove-like depressions 27 (see in particular FIG. 3) are formed, which respectively form interruptions in the curvature course of the main separating surface between the wall sections 23.
• the clear width of the annular groove-like depressions 27 at the open end of the folds 17, 19 is in each case substantially smaller than the fold height measured along the vertical axis 25, and indeed in the illustrated example the height of the folds 19 is approximately larger by a factor of 4.
• the inner sides of the recesses 27 of the folds 17, 19 are slightly diverging towards the open end, so that the open end of the recesses 27 has a greater width than the bottom of the recesses 27 at the apex region of the folds ,
• the vertical axes 25 of the gaps 19 each extend approximately perpendicular to the tangential plane to the adjacent wall portions 23, while the vertical axis 25 of the first fold 17 is slightly inclined to this tangential plane, wherein the vertical axis 25 of the first fold 17 with the plane of the annular edge 13 forms an angle of about 10 °.
• the vertical axes 25 are increasingly inclined from fold to fold to the plane of the edge 13.
• annular bead-like elevations are formed by folding 17 and 19, resulting in a particularly easy mobility for curling the membrane.
• ring-bead-like elevations could be provided. It is possible to use unfilled PTFE materials or those with filler and / or filler combinations, as may be provided in a manner known per se with PTFE materials, for example if extreme temperature resistance or other special properties are desired. Glass fiber materials, carbon or metallic fillers may be considered among others.
• PTFE materials are semi-finished in many forms available, for example, blocks peeled from slabs, rods, rounds and the like. Due to the mechanical properties of finished products, such as the rolling membrane used in the pressure vessel according to the invention, can be prepared by machining of moldings, which in turn are pressed from powdered raw material and sintered. In particular, in the case of thin-walled products, shaping by blow-molding of a PTFE dispersion before sintering is also possible. If the membrane spherical shape shown in FIG. 1 is obtained from a solid polytetrafluoroethylene solid, it is then machined of the green body into the separation membrane shape shown. In order to minimize the polytetrafluoroethylene waste produced during the cutting process, it is preferable to produce a preform body as a blank in a sheath mold as a press mold.
• the said polytetrafluoroethylene material as the fluoroplastic material may comprise both pure PTFE and modified PTFE and include both unfilled PTFE and PTFE compounds.
• modified PTFE material fillers such as bronze, carbon dust, MoS 2 and glass fiber and carbon fiber materials come into question.
• other fluoroplastic materials include ethylene tetrafluoroethylene (ETFE), ethylene chlorotrifluoroethylene copolymer (ECTFE), polychlorotrifluoroethylene copolymer (PCTFE), perfluoroalkoxy copolymer (PFA), polyvinylidene fluoride (PVDF), and tetrafluoroethylene-perfluoropropylene (FEP).

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Supply Devices, Intensifiers, Converters, And Telemotors (AREA)
• Diaphragms And Bellows (AREA)

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

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• 2007
  • 2007-01-25 DE DE102007003724A patent/DE102007003724A1/de not_active Withdrawn
  • 2007-12-04 JP JP2009546656A patent/JP5319551B2/ja active Active
  • 2007-12-04 EP EP07856342A patent/EP2126368B1/fr active Active
  • 2007-12-04 US US12/448,674 patent/US8418726B2/en active Active
  • 2007-12-04 WO PCT/EP2007/010500 patent/WO2008089812A1/fr active Application Filing
  • 2007-12-04 AT AT07856342T patent/ATE534824T1/de active

Non-Patent Citations (1)

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