SELF-LOCKING MEMBRANE SYSTEM

Abstract

A membrane system comprising a membrane and connecting elements for connecting the membrane to a membrane pump for conveying a fluid, which membrane pump has a drive shaft designed for an oscillating translatory movement perpendicular to the plane of the membrane during operation of the membrane pump and has an external thread at an end portion for engagement with the membrane system by screwing. To ensure a secure and torque-proof connection between the membrane and the connecting element to be screwed to a drive shaft, the connecting elements comprise a threaded socket, a thrust ring and a thrust plate.

Claims

1-9. (canceled)

10. A membrane system comprising a membrane and connecting elements for connecting the membrane to a membrane pump for conveying a fluid, which membrane pump has a drive shaft designed for an oscillating translatory movement perpendicular to the plane of the membrane during operation of the membrane pump and has an external thread at an end portion for engagement with the membrane system by screwing, Wherein the connecting elements comprise a threaded socket, a thrust ring and a thrust plate, wherein the threaded socket has a cylindrical section arranged coaxially with an axis perpendicular to the plane of the membrane, is fixedly or detachably connected to the membrane on the outside of the circumferential surface of its cylindrical section has a socket male thread, and on the inside of the circumferential surface of its cylindrical section has a socket female thread, preferably a blind hole thread, wherein the thrust ring has a cylindrical portion arranged coaxially with the cylindrical portion of the threaded socket, and on the inner side of the circumferential surface of its cylindrical section has a thrust ring female thread (6) which is formed as a mating thread to the socket male thread of the threaded socket wherein the thrust plate has a cylindrical section arranged coaxially with the cylindrical section of the threaded socket on the outside of the circumferential surface of its cylindrical portion, has a thrust plate male thread formed as a mating thread to the socket female thread of the threaded socket, and on the inside of the circumferential surface of its cylindrical portion, a thrust plate female thread adapted to be connected to the male thread at an end portion of a drive shaft of a membrane pump, wherein the thrust plate male thread of the thrust plate and the socket female thread of the threaded socket formed as a mating thread thereof have a different thread pitch, a different thread rotation direction, or both a different thread pitch and a different thread rotation direction than the thrust plate female thread of the thrust ring and the socket male thread of the threaded socket formed as a mating thread thereof, and wherein the thrust plate can be connected or is connected to the thrust ring in a torque-proof manner via a connecting section.

11. The membrane system according to claim 10, wherein the thrust plate has at least one connecting section extending radially outwardly from the end of its cylindrical section facing away from the membrane, which connecting section extends at least as far as the thrust ring or beyond its end facing away from the membrane.

12. The membrane system according to claim 10, wherein at the thrust plate a connecting section is provided which extends radially outwardly from the cylindrical section of the thrust plate in the form of a circular disc, or two or more connecting portions are provided which are formed as webs or tabs extending radially outwardly from the cylindrical portion of the thrust plate.

13. The membrane system according to claim 10, wherein the torque-resistant connection of the thrust plate to the thrust ring is an adhesive connection, a welded connection, a bolt connection, a form-fit connection, a snap-in connection or a combination of two or more of the aforementioned connections.

14. The membrane system according to claim 10, wherein the thrust ring has at least one cutout or groove open in the direction of the thrust plate.

15. The membrane system according to claim 10, wherein the threaded socket is manufactured integrally with the membrane from the same material.

16. The membrane system according to claim 10, wherein the membrane is made of polytetrafluoroethylene (PTFE) and/or the threaded socket is made of polytetrafluoroethylene (PTFE) and/or the thrust ring is made of polyphenyl ether (PPE) or a derivative thereof or of a polymer blend containing polyphenyl ether (PPE) or a derivative thereof or of a polymer alloy containing polyphenyl ether (PPE) or a derivative thereof, wherein the polymer, the polymer blend or the polymer alloy is preferably glass fiber reinforced, and/or the thrust plate is manufactured from metal or a metal alloy, preferably from brass.

17. The membrane system according to claim 10, wherein the membrane system further comprises at least one bolt or securing pin extending through the connecting portion of the thrust plate, preferably through through-holes in the connecting portion of the thrust plate, into the cylindrical portion of the threaded socket.

18. A membrane pump for conveying a fluid, comprising a membrane system according to claim 10 and a drive shaft adapted for oscillating translatory movement perpendicular to the plane of the membrane during operation of the membrane pump and having an external thread at an end portion for engagement with the membrane system by screwing.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0049] Further advantages, features and possible applications of the present invention will become apparent from the following description and the accompanying figures. In the figures, corresponding elements are designated by the same reference signs.

[0050] FIG. 1 shows a cross-sectional view of an embodiment of a membrane system according to the invention with a membrane, a threaded socket formed integrally with the membrane, a thrust ring and a thrust plate in assembly.

[0051] FIG. 2A shows a top view of the membrane with threaded socket integrally formed thereon according to the embodiment shown in FIG. 1.

[0052] FIG. 2B shows a cross sectional view along A-A of the membrane with threaded socket integrally formed thereon according to the embodiment shown in FIG. 1.

[0053] FIG. 2C shows a perspective view of the membrane with threaded socket integrally formed thereon according to the embodiment shown in FIG. 1.

[0054] FIG. 3A shows a bottom view of the thrust ring according to the embodiment shown in FIG. 1.

[0055] FIG. 3B shows a cross-sectional view along line A-A of the thrust ring according to the embodiment shown in FIG. 1.

[0056] FIG. 3C shows a perspective view of the thrust ring according to the embodiment shown in FIG. 1.

[0057] FIG. 4A shows a top view of the thrust plate according to the embodiment shown in FIG. 1.

[0058] FIG. 4B shows a cross-sectional view along line A-A view of the thrust plate according to the embodiment shown in FIG. 1.

[0059] FIG. 4C shows a perspective view of the thrust plate according to the embodiment shown in FIG. 1.

[0060] FIG. 5A shows a cross-sectional view of a prior art membrane system with membrane, a trunnion integral with the membrane, and a membrane thrust piece in assembly.

[0061] FIG. 5B shows a perspective view of the prior art membrane with trunnion integral therewith.

DETAILED DESCRIPTION

[0062] FIGS. 1 to 4 show different representations and views of an embodiment of a membrane system according to the invention with a PTFE membrane 1, a threaded socket 2 formed integrally with the membrane 1 and therefore also made of PTFE, a thrust ring 5 and a thrust plate 8. FIG. 1 shows a cross-sectional view of the membrane system in assembly, while FIGS. 2 to 4 show the components membrane 1 with threaded socket 2, thrust ring 5 and thrust plate 8 connected in FIG. 1, each individually in different views.

[0063] The membrane 1 is essentially circular disc-shaped. As can be seen in the cross-sectional view of FIG. 1 and also in FIGS. 2b and 2c, the diaphragm 1 is thicker at its circumferential edge than in sections lying further inward, since the diaphragm is usually connected with its circumferential edge firmly and fluid-tightly to the housing of the pumping chamber of a diaphragm pump by clamping the circumferential edge of the diaphragm between housing parts of the pumping chamber and the working chamber of the diaphragm pump. The sections of the membrane further inwards from the circumferential edge are initially thinner in order to ensure sufficient flexibility and pliability during oscillating back and forth movement of the membrane in operation, the material of the membrane being made stronger again towards the center for a stable and firm structure in the one-piece design with the threaded socket 2 adjoining the membrane 1.

[0064] The threaded socket 2 comprises or consists essentially of a cylindrical section coaxial with the axis perpendicular to the plane of the membrane and passing through the center of the membrane. On the outer side of the circumferential surface of its cylindrical section, the threaded socket 2 has a socket male thread 3 for screw connection to the thrust ring 5 and on the opposite inner side of the circumferential surface a socket female thread 4 for screw connection to the thrust plate 8.

[0065] The thrust ring 5 comprises a cylindrical section which is arranged coaxially with the cylindrical section of the threaded socket 2 and has, on the inside of the circumferential surface of its cylindrical section, a thrust ring female thread 6 which is designed as a mating thread to the socket male thread 3 for screwing onto the threaded socket 2. In the present embodiment, the thrust ring is manufactured from glass fiber reinforced polyphenyl ether (PPE+GF). The blind holes 14 on the thrust ring 5 shown in FIGS. 1 and 3 serve to engage a tool when screwing the thrust ring onto the threaded socket 2.

[0066] The thrust plate 8 also has a cylindrical portion arranged coaxially with the cylindrical portion of the threaded socket 2, and, on the outer side of the circumferential surface of its cylindrical portion, a thrust plate male thread 9 formed as a mating thread to the socket female thread 4 of the threaded socket 2, and, on the inner side of the circumferential surface of its cylindrical portion, a thrust plate female thread 10 formed for connecting with the male thread at an end portion of a drive shaft of a membrane pump.

[0067] Furthermore, the cylindrical portion of the thrust plate 8 is adjoined by a connecting portion formed as a circular disk which extends radially outward from the cylindrical portion of the thrust plate 8. The cylindrical portion of the thrust plate is thus perpendicular to the circular disk, so that the thrust plate has a substantially hat shape in cross-section. In the present embodiment, the thrust plate 8 is manufactured from brass.

[0068] To assemble the diaphragm system according to the invention, the thrust ring 5 with the thrust ring female thread 6 is first screwed onto the socket male thread 3 of the threaded socket 2 until the thrust ring is in contact with the diaphragm. In the present embodiment, an adhesive connection is manufactured between the thrust plate 8 and thrust ring 5 for the torque-proof connection required by the invention. For this purpose, after screwing the thrust ring 5 onto the threaded socket 2, an adhesive is applied to the thrust ring 5 and then the thrust plate 8 with the thrust plate male thread 9 is screwed into the socket female thread 4 of the threaded socket 2. In the present embodiment, the thrust ring 5 additionally has a circumferential groove 7 open in the direction of the thrust plate 8, into which adhesive is also applied in order to achieve a particularly stable connection between the thrust ring 5 and the thrust plate 8 after the adhesive has cured. Furthermore, in the present embodiment, two additional bores 13 are furthermore provided in the connecting section 11 of the thrust plate 8, into which adhesive can also pene-trate, thus creating additional bonding surfaces and, after the adhesive has cured, also additional sections with a form-fit connection against a rotational movement of the thrust plate 8 relative to the thrust ring 5. Once the adhesive has cured, the thrust plate 8 and the thrust ring 5 are firmly connected to each other, in particular torque-proof.

[0069] In the present embodiment, the socket male thread 3 of the thrust ring 2 and the thrust ring female thread 6 of the thrust ring 5 are designed as right-handed M18?1.25 fine pitch threads, while the socket female thread 4 of the thrust ring 2 and the thrust plate male thread 9 of the thrust plate 8 are designed as right-handed M8?0.75 fine pitch threads. The thrust plate female thread 10 for screwing to the drive shaft of a membrane pump is an M5?0.8 standard thread. Alternatively, right-hand and left-hand threads with the same or different thread pitch can be combined.

[0070] The combination of the torque-proof connection between thrust plate 8 and thrust ring 5 with the different thread pitches (or also different thread runnings) on the thrust plate male thread 9 and socket female thread 4 on the one hand and thrust ring female thread 6 and socket male thread 9 on the other hand achieves a self-locking effect against the thrust plate 8 connected to thrust ring 5 being unscrewed from the threaded socket 2. The self-locking prevents the thrust plate 8 from detaching from the threaded socket 2 on the diaphragm 1 when the diaphragm is unscrewed from the drive shaft of a diaphragm pump and from remaining on the drive shaft.

[0071] In the present embodiment, two through-holes 12 are provided in the circular disc-shaped connecting section 11 of the thrust plate 8, through which bolts or securing pins (not shown here) can be inserted and anchored in the comparatively soft material PTFE of the cylindrical section of the threaded socket 2 to supplement the torque-proof adhesive connection with the thrust ring. This ensures additional torque protection of the thrust plate 8 with respect to the threaded socket 2. Simple metal pins, preferably sharpened for easier driving into the material of the threaded socket 2, or alternatively screws with a self-tapping or self-drilling thread can be con-sidered as bolts or securing pins.

[0072] FIG. 5a shows a cross-sectional view of a membrane system according to the prior art described above with a PTFE membrane 20, which is manufactured in one piece with a trunnion 21 of PTFE arranged centrally on the membrane 20 and extending perpendicular to the plane of the membrane. The trunnion 21 has a circular cross-section and has a trunnion male thread 22 on its circumferential surface. Threaded onto the trunnion 21 made of PTFE is a substantially cylindrical membrane thrust piece 23 made of a hard polymeric material. For this purpose, starting from one end of the cylinder, the cylindrical membrane thrust piece 23 has a first thrust piece female thread 24, which is designed as a mating thread for screwing to the male thread 22 of the trunnion 21. Starting from the opposite end of the cylindrical membrane thrust piece 23, a second thrust piece female thread 25 is provided, which is designed as a mating thread to the male thread on the drive shaft of a membrane pump and is provided for connecting the membrane to the drive shaft. FIG. 5b shows a perspective view of the PTFE membrane 20 with the trunnion 21 manufactured in one piece therewith and extending perpendicular to the plane of the membrane, without the membrane thrust piece fixed thereto.

[0073] Since the membrane thrust piece 23 is merely screwed onto the PTFE, trunnion 21, one or more metal bolts or split pins (not shown here) must be driven through one or more holes in the membrane thrust piece (not shown here) into the PTFE material of the trunnion for torque-proof securing of the membrane thrust piece 23 to the PTFE trunnion 21 to ensure that the membrane 20 with the trunnion 21 does not move away from the PTFE, membrane thrust piece 20 when it is unscrewed from a drive shaft for dismantling or from the membrane thrust piece 23 when unscrewing it from a drive shaft for disassembly or replacement, and the latter remains on the thread of the drive shaft.

[0074] Comparison of FIGS. 1 and 5 reveals a further disadvantage of the prior art structure, namely that the cylindrical membrane thrust piece 23 must be comparatively long in design since it must receive a thread from each end, which in turn limits the usability of such PTFE membranes.

[0075] For purposes of the original disclosure, it is pointed out that all features as they appear to a person skilled in the art from the present description, the drawings and the claims, even if they have been specifically described only in connection with certain further features, can be combined both individually and in any desired combinations with other of the features or groups of features disclosed herein, unless it has been expressly excluded or technical circumstances make such combinations impossible or pointless. The comprehensive, explicit presentation of all conceivable combinations of features is omitted here only for the sake of brevity and reada-bility of the description.

[0076] While the invention has been illustrated and described in detail in the drawings and the forego-ing description, this description of presentation is by way of example only and is not intended to limit the scope of protection as defined by the claims. The invention is not restricted to the embodiments shown.

[0077] Variations of the disclosed embodiments will be obvious to those skilled in the art from the drawings, description and appended claims. In the claims, the word having does not exclude other elements, and the indefinite article one or a does not exclude a plurality. The mere fact that certain features are claimed in different claims does not preclude their combination.

REFERENCE LIST

[0078] 1 membrane [0079] 2 threaded socket [0080] 3 socket male thread [0081] 4 socket female thread [0082] 5 thrust ring [0083] 6 thrust ring female thread [0084] 7 groove on thrust ring [0085] 8 thrust plate [0086] 9 thrust plate male thread [0087] 10 thrust plate female thread [0088] 11 connecting section of thrust plate [0089] 12 through hole on the connecting section of the thrust plate [0090] 13 holes on thrust plate [0091] 14 blind holes for tool engagement on thrust ring [0092] 20 membrane [0093] 21 trunnion [0094] 22 trunnion male thread [0095] 23 membrane thrust piece [0096] 24 first thrust piece female thread [0097] 25 second thrust piece female thread