Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B43/00—Machines, pumps, or pumping installations having flexible working members
  • F04B43/0009—Special features
  • F04B43/0054—Special features particularities of the flexible members
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B43/00—Machines, pumps, or pumping installations having flexible working members
  • F04B43/0009—Special features
  • F04B43/0054—Special features particularities of the flexible members
  • F04B43/0063—Special features particularities of the flexible members bell-shaped flexible members
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B13/00—Pumps specially modified to deliver fixed or variable measured quantities
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B37/00—Pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B25/00 - F04B35/00
  • F04B37/10—Pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B25/00 - F04B35/00 for special use
  • F04B37/14—Pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B25/00 - F04B35/00 for special use to obtain high vacuum
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B43/00—Machines, pumps, or pumping installations having flexible working members
  • F04B43/02—Machines, pumps, or pumping installations having flexible working members having plate-like flexible members, e.g. diaphragms
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B45/00—Pumps or pumping installations having flexible working members and specially adapted for elastic fluids
  • F04B45/04—Pumps or pumping installations having flexible working members and specially adapted for elastic fluids having plate-like flexible members, e.g. diaphragms
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
  • F05C2225/00—Synthetic polymers, e.g. plastics; Rubber
  • F05C2225/02—Rubber
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
  • F05C2225/00—Synthetic polymers, e.g. plastics; Rubber
  • F05C2225/08—Thermoplastics

Definitions

• the present invention relates to a composite membrane with a flexible membrane body comprising a circumferential edge, a base, and a flexible membrane section connecting the circumferential edge to the base.
• the circumferential edge in particular, forms a clamping surface over which the composite membrane can be arranged, for example, within a diaphragm pump.
• Composite diaphragms of the type described above can be used, for example, to convert differential pressures, particularly in servo elements, actuators, brake boosters, or similar devices. They can also be used in pressure reducers, pressure regulators, or flow controllers. Furthermore, they are suitable for use in valve applications, such as pressure relief valves, safety valves, shut-off valves, or check valves.
• the invention preferably relates to composite diaphragms intended for use in diaphragm pumps and thus for pump applications.
• Such pumps can be, for example, metering pumps, mechanical pumps, diaphragm compressors, or vacuum pumps.
• Composite membranes are typically circular and have a disc-shaped base. For this reason, they are also referred to as disc-shaped membranes.
• the invention is not limited to such designs, but also relates to rolled membranes, corrugated membranes, dome-shaped membranes, and flat membranes.
• the corresponding composite membrane can then be clamped at its edge, while the base of the composite membrane performs lifting movements, whereby with each lifting movement the flexible membrane section is turned inside out, so that rolling movements of the flexible material can be observed in a radial section.
• the flexible membrane section is also referred to as a rolling loop in the prior art.
• the base typically does not participate in the rolling motion, so an insert made of an inflexible or dimensionally stable material can be arranged within it. This insert is then connected to the piston rod, allowing the rolling motion to be transmitted through the insert into the composite membrane.
• the membrane body is usually at least partially made of polytetrafluoroethylene (PTFE) and forms a media-side contact layer. This is typically provided as a separate contact film, which can then be bonded to a base material of the membrane body.
• PTFE polytetrafluoroethylene
• the invention aims to provide a composite membrane which can still be used in a known manner, particularly with chemically aggressive and toxic media, but which is also characterized by better recyclability.
• the object and solution of this problem is a composite membrane with a flexible membrane body having a circumferential edge, a base and a flexible membrane section connecting the circumferential edge to the base, wherein, according to the invention, the membrane body is provided to be at least partially made of ultra-high molecular weight polyethylene (PE-UHMW).
• PE-UHMW ultra-high molecular weight polyethylene
• ultra-high molecular weight polyethylene is understood to mean polyethylene having an average molecular weight of at least 5000 g/mol, preferably at least 10000 g/mol, and particularly preferably at least 50000 g/mol.
• the average molecular weight of such polyethylenes is between 5000 and 50 million g/mol, preferably between 10000 and 10 million g/mol, and particularly preferably between 50000 and 2 million g/mol.
• Ultra-high molecular weight polyethylene like polytetrafluoroethylene, is characterized by high chemical resistance. Furthermore, tests have shown that even with the use of corresponding composite membranes and despite a high number of rolling cycles, a high structural integrity is still maintained. The stability of the membrane body can be ensured. Based on such an inventive design, the use of polytetrafluoroethylene can therefore be dispensed with.
• the membrane body preferably the entire composite membrane, is designed completely without polytetrafluoroethylene.
• the membrane body is formed entirely of ultra-high molecular weight polyethylene, at least on a first surface.
• the first surface is, in particular, the surface of the membrane body that forms the media side, or which, in the intended use, for example in a diaphragm pump, comes into contact with the medium being pumped.
• the complete formation of this surface from ultra-high molecular weight polyethylene ensures that only the ultra-high molecular weight polyethylene comes into contact with the medium, thus guaranteeing the chemical resistance of the composite membrane through the use of ultra-high molecular weight polyethylene.
• the membrane body is multilayered.
• the membrane body comprises a surface layer made of ultra-high molecular weight polyethylene and a base layer.
• the ultra-high molecular weight polyethylene is preferably provided exclusively within a surface layer, which is then arranged on a base layer of the membrane body.
• the base layer can then also form a second surface, which is arranged on a side of the composite membrane facing away from the media.
• the base layer is preferably formed from an elastomer.
• the elastomer is preferably selected from the group consisting of acrylonitrile butadiene rubber (NBR), hydrogenated acrylonitrile butadiene rubber (HNBA), ethylene propylene diene monomer rubber (EPDM), chloropene rubber (CR), styrene butadiene rubber (SBR), fluororubber (FKM), silicone rubber (VMQ), and fluorosilicone rubber (FVMQ).
• NBR acrylonitrile butadiene rubber
• HNBA hydrogenated acrylonitrile butadiene rubber
• EPDM ethylene propylene diene monomer rubber
• CR chloropene rubber
• SBR styrene butadiene rubber
• FKM fluororubber
• silicone rubber VMQ
• FVMQ fluorosilicone rubber
• the overlay layer can be bonded to the base layer in various ways.
• a preferred design involves the overlay layer being directly bonded to the base layer.
• the base layer is made of ethylene propylene diene monomer (EPDM) rubber.
• EPDM ethylene propylene diene monomer
• the membrane body, or at least the overlay layer can be directly bonded to the base layer.
• This bonding is preferably achieved through compression molding.
• the material for the base layer is placed inside a molding press, which consists of an upper and a lower molding section that together form the shape of the finished composite membrane. By applying heat and pressure, the corresponding composite membrane can then be formed from the material for the base layer.
• the base layer and the top layer are thenbonded together during the compression molding process.
• the top layer is then provided as a separately manufactured top sheet and positioned above the base layer material within the compression mold. The pressure and heat then vulcanize the materials together.
• the adhesive effect between the base layer and the top layer has proven to be sufficiently stable, so that further measures to strengthen the adhesive effect are not absolutely necessary.
• an alternative design can provide for an adhesion promoter layer between the top layer and the base layer. Accordingly, the top layer can bond to the base layer by incorporating this adhesion promoter layer.
• the adhesion promoter layer consists, in particular, of a polyurethane adhesive.
• a preferred embodiment of the invention further provides that a reinforcing layer is arranged in the base layer.
• This reinforcing layer increases the strength of the membrane body.
• the reinforcing layer is formed from a fabric, especially polyamide, polyester and/or high-temperature polyamide.
• the bearing layer forms exclusively a closed first surface. Accordingly, the bearing layer can be comparatively thin. In particular, it is provided that the bearing layer has a thickness between 0.15 and 1.5 mm, preferably between 0.2 and 1.2 mm.
• the flexible membrane section has a plurality of nubs.
• the nubs can also form raised areas in the support layer.
• the nubs are shaped like spherical caps with a circular or elliptical base.
• the nubs create point stiffeners in the flexible membrane section.
• the areas between the nubs are flexible, allowing the flexible membrane section to be inverted with minimal pressure, and the point stiffeners prevent creases or folds from forming in the support layer.
• the composite membrane performs defined rolling movements during use, with low rolling resistance at the fold. Furthermore, the studded structure of the composite membrane on the media side ensures better adhesion between the membrane body and the ultra-high-molecular-weight polyethylene (UHPE) layer. This improved adhesion of the layered composite is due to an interlocking effect of the studs and/or a larger surface area resulting from the studded features.
• UHPE ultra-high-molecular-weight polyethylene
• a particularly preferred embodiment of the invention further provides that the base forms a chamber in which an insert is arranged, at least partially.
• the chamber is formed by an upper and a lower wall, the upper wall forming part of the first surface, and the insert being arranged between the upper and lower walls.
• the insert is preferably a dimensionally stable insert, which is accordingly made of a dimensionally stable material.
• the insert is intended to be made of aluminum, brass, steel, stainless steel, or plastic.
• the insert may also have a receptacle for a piston rod.
• This receptacle is... in particular a recess with internal thread arranged in the insert or a protrusion with external thread, so that the piston rod can be attached to the insert via the corresponding thread.
• the invention provides that a diaphragm pump is also part of the invention, wherein the diaphragm pump has a composite membrane according to the invention.
• the Fig. 1 Figure 1 shows a composite membrane according to the invention.
• the composite membrane has a flexible membrane body, which in turn has a clamping surface 3 on a circumferential edge 2, which is connected to a base 4 via a flexible membrane section 5.
• the base 4 consists of an upper and a lower wall 6a, 6b, wherein the walls 6a, 6b form a chamber 7 arranged between the walls 6a, 6b, in which an insert 8 made of a dimensionally stable material is arranged.
• the membrane body 4 is multilayered and consists essentially of a base layer 9 made of an elastomer and a support layer 10 arranged on it.
• a reinforcement layer 11 is arranged within the base layer 9, which is intended to increase the strength of the membrane body.
• the coating layer 11 is now made of ultra-high molecular weight polyethylene (UHMWPE).
• UHMWPE ultra-high molecular weight polyethylene
• PTFE polytetrafluoroethylene
• the coating layer 11 is now made of ultra-high molecular weight polyethylene (UHMWPE).
• PTFE polytetrafluoroethylene
• the coating layer 11 is now made of ultra-high molecular weight polyethylene (UHMWPE).
• PTFE polytetrafluoroethylene
• ultra-high molecular weight polyethylene can be recycled much more easily and in a more environmentally friendly manner.
• the Fig. 1 Furthermore, the figure shows that the support layer 10 is located on a first surface 12 facing the media side.
• the base layer 9 can be co-extruded together with the support layer 10, resulting in sufficient bond strength between the base layer 9 and the support layer 10.
• the support layer 10 it is also conceivable to provide the support layer 10 as a separate support film, which is then bonded to the base layer 9 by incorporating an adhesion promoter layer (not shown in detail).
• an adhesion promoter layer not shown in detail
• materials for the base layer 9 that would otherwise not form sufficient bond strength with the support layer 10 without the inclusion of an adhesion promoter layer.
• EPDM it is intended that the base layer 9 be co-extruded together with the support layer 10.
• the second surface of the membrane body 1 is formed by the base layer 9, which is accordingly the side facing away from the medium.
• the second surface 13 has an opening in the base 4 through which the insert 8 extends.
• the insert 8 has an internal thread 14 via which a membrane piston (not shown) can be connected to the insert 8.
• the Fig. 2 shows a further development of the composite membrane according to the Fig. 1 , whereby the clamping surface 3 is now formed by thickenings on the edge.
• a large number of studs 15 are provided in the area of the flexible membrane section 5, which are also located in the Fig. 1 are shown, but according to the Fig. 2 These nubs form 15 elevations in the support layer 10. This further improves the bond strength between the base layer 9 and the support layer 10.
• the one in Fig. 3 The composite membrane shown has a design that largely corresponds to that described in the Fig. 1 and 2
• the composite membranes shown are shown, but now the bottom 4 has only a wall 6 which does not form a chamber 7, so that accordingly no insert 8 can be arranged within a corresponding chamber 7.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Diaphragms And Bellows (AREA)
• Reciprocating Pumps (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=96093270

Family Applications (1)

Country Status (4)

Citations (8)

Family Cites Families (12)

• 2024
  • 2024-07-04 DE DE102024119053.1A patent/DE102024119053A1/de active Pending
• 2025
  • 2025-06-25 EP EP25185152.3A patent/EP4675104A1/fr active Pending
  • 2025-07-02 US US19/258,142 patent/US20260009379A1/en active Pending
  • 2025-07-04 CN CN202510920886.XA patent/CN121273588A/zh active Pending

Patent Citations (8)

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