PUMP DIAPHRAGM

Abstract

A pump diaphragm for a diaphragm pump for conveying a fluid includes a solid core with a connection device for a drive rod of the diaphragm pump, and a plate-shaped elastic diaphragm body made of rubber having a peripheral clamping edge. The solid core is embedded at least partially in the diaphragm body and the solid core is produced from a thermoplastic and forms covalent bonds with the elastic diaphragm body made of rubber without adhesive. For this purpose, the thermoplastic, for example polyamide 612 or polyphenylene ether, and the rubber, a periodically cross-linked rubber such as EPDM, are selected in such a way that they are covalently cross-linked with one another at the boundary layer. In this way, a bonding layer that is susceptible to weakening or destruction is not present between the core and the diaphragm body.

Claims

1. A pump membrane for conveying fluids comprising a solid core with a connection member for a drive rod of the diaphragm pump and a plate-shaped, elastic diaphragm body made of rubber with a peripheral clamping edge, wherein the solid core is at least partially embedded in the diaphragm body, wherein the solid core is produced from a thermoplastic and forms covalent bonds with the elastic diaphragm body made of rubber without adhesive.

2. The pump membrane according to claim 1, wherein the rubber is a peroxidically cross-linked rubber.

3. The pump membrane according to claim 1, wherein the thermoplastic is a polyamide 612 or a polyphenylene ether.

4. The pump membrane according to claim 1, wherein the rubber is a silicone rubber or a fluorosilicone rubber (MVQ/FMQV) and the thermoplastic is a polybutylene terephthalate (PBT).

5. The pump membrane according to claim 1, wherein the solid core comprises a plate-shaped anchoring plate, wherein the anchoring plate comprises a plurality of through-holes arranged in a circular manner around the longitudinal axis of the pump diaphragm, which through-holes in each case have a constriction of the cross-section, as viewed from the side facing away from the fluid in the direction of the side facing the fluid.

6. The pump membrane according to claim 1, wherein the solid core comprises a plate-shaped anchoring plate, wherein the anchoring plate comprises an annular groove at the side facing away from the fluid and a plurality of through-holes are arranged in the groove.

7. The pump membrane according to claim 1, wherein the solid core comprises a peg, at the end whereof facing away from the fluid the connection member is arranged.

8. The pump membrane according to claim 7, wherein the peg comprises a central blind hole at the side facing away from the fluid.

9. The pump membrane according to claim 1, wherein the connection member is a metallic threaded insert.

10. The pump membrane according to claim 2, wherein the rubber is a peroxidically cross-linked ethylene-propylene-diene rubber (EPDM).

11. The pump membrane according to claim 3, wherein the thermoplastic is poly-2,6-dimethyl-1,4-phenylene ether.

Description

BRIEF EXPLANATION OF THE FIGURES

[0027] The invention will be explained in greater detail below with the aid of examples of embodiment in conjunction with the drawing(s). In the figures:

[0028] FIG. 1 shows a perspective view onto the side of a pump diaphragm facing away from the fluid comprising a solid core and an elastic diaphragm body;

[0029] FIG. 2 shows a cross-sectional representation of the pump diaphragm;

[0030] FIG. 3 shows a perspective view onto the side of a solid core of the pump diaphragm that is facing away from the fluid;

[0031] FIG. 4 shows a perspective view onto the side of the solid core facing the fluid; and

[0032] FIG. 5 shows a perspective partially cross-sectional representation of the pump diaphragm.

WAYS OF PERFORMING THE INVENTION

[0033] FIG. 1 shows a perspective view of a pump diaphragm 1 for a diaphragm pump, in particular a metering diaphragm pump, for conveying a fluid. FIG. 2 shows a cross-sectional representation through the pump diaphragm from FIG. 1. Pump diaphragm 1 comprises a plate-shaped, elastic diaphragm body 2 made of rubber with a circular functional region 8 and a peripheral clamping edge 6 encircling a longitudinal axis A of pump diaphragm 1. Longitudinal axis A runs through the centre of circular functional region 8 and parallel to the deflection direction of pump diaphragm 1. Pump diaphragm 1, in the installed state, is held in a sealing manner with clamping edge 6 in a pump housing to delimit a pump chamber in which the fluid to be pumped flows. In the embodiment shown, clamping edge 6 is formed T-shaped in cross-section. Other shapes are also possible.

[0034] Furthermore, pump diaphragm 1 comprises a solid core 3, which is at least partially embedded in diaphragm body 2 and on the fluid side, i.e. towards the pump chamber, is completely covered by diaphragm body 2. On the side facing away from the fluid, core 3 comprises a connection means 4, which can be in an operative connection with the drive of the diaphragm pump for deflecting pump diaphragm 1 along longitudinal axis A.

[0035] For the chemical anchoring of core 3 in diaphragm body 2, core 3 is produced in one piece from a thermoplastic, which forms covalent bonds with elastic diaphragm body 2 made of rubber without adhesive. The thermoplastic can be a polyamide 612 or a polyphenylene ether, in particular poly-2,6-dimethyl-1,4-phenylene ether, which enters into covalent bonds with peroxidically cross-linked rubber, preferably peroxidically cross-linked ethylene-propylene-diene rubber (EPDM). The covalent bonds arise during the vulcanisation of the rubber.

[0036] Alternatively, a silicone rubber or a fluorosilicone rubber (MVQ/FMQV) can be used as rubber and a polybutylene terephthalate (PBT) as plastic.

[0037] For the mechanical anchoring, core 3 comprises an anchoring plate 5, which is covered at least partially by diaphragm body 2 at the side facing away from the fluid. In the shown embodiment, core 3 also comprises a peg 7, and connection means 4 is not arranged directly in anchoring plate 5, but rather at the end of peg 7 facing away from the fluid.

[0038] Furthermore, in the shown embodiment, connection means 4 is fixed in the core as a separate part, e.g. in the form of a threaded insert. Core 7 can also be constituted polygonal at the end facing away from the fluid, so that it can be screwed tight to the drive rod using an Allen key.

[0039] Pump diaphragm 1 can be produced by injection moulding technology, for example by a two-component injection moulding process, in which first the solid core and then diaphragm body 2 are injected. A metallic connection means 4, e.g. in the form of a threaded insert, can be injection moulded directly with the core material.

[0040] FIG. 3 and FIG. 4 show a perspective exploded view onto solid core 3 on the side facing away from the fluid and the side facing the fluid. FIG. 5 shows a perspective partially cross-sectional representation of pump diaphragm 1 from FIGS. 1 and 2 with the core from FIGS. 3 and 4. Anchoring plate 5 comprises an inner ring comprising a plurality of inner through-holes 51 arranged around longitudinal axis A. As can be seen in FIG. 2 and in FIG. 5, inner through-holes 51 for the mechanical anchoring of core 3 in diaphragm body 2 in each case comprise a circumferential shoulder, so that they are constricted on the fluid side. Inner through-holes 51 of anchoring plate 5 are filled, in finished pump diaphragm 1, completely with the rubber of the diaphragm body. As additional mechanical anchoring, anchoring plate 5 also comprises on the side facing away from the fluid an annular groove 52, in which an outer ring comprising a plurality of outer through-holes 53 is arranged. In addition, in the example of embodiment shown, outer wall 54 of groove 52 has a smaller height than inner wall 55 of groove 52, so that, in finished pump diaphragm 1, diaphragm body 2 surrounds the peripheral edge of anchoring plate 5 with its outer wall 54 and completely fills groove 52 together with outer through-holes 53.

[0041] Furthermore, core 3 comprises a central opening 31 on the fluid side, which together with the connection means constitutes a blind hole. It finished pump diaphragm 1, this blind hole is also filled with the rubber of diaphragm body 2. The described structures of core 2 (through-holes, groove, blind hole) all lead to an enlargement of the bonding area between core 3 and diaphragm body 2, which, particularly in the case of the previous described chemical anchoring, leads to a much more durable and stronger fastening of core 3 in diaphragm body 2.

REFERENCE LIST

[0042] 1 pump diaphragm [0043] 2 diaphragm body [0044] 3 core [0045] 4 connection means [0046] 5 anchoring plate [0047] 6 clamping edge [0048] 7 peg [0049] 8 functional region [0050] 31 central opening/central blind hole [0051] 51 inner through-holes [0052] 52 annular groove [0053] 53 outer through-holes [0054] 54 outer wall [0055] 55 inner wall [0056] A longitudinal axis