| 摘要 |
A diaphragm pump (1) with a working diaphragm (16) is provided with an additional diaphragm (26) arranged at a distance (a) from the working diaphragm (16), between the working diaphragm and eccentric drive (7). The diaphragm pump (1) provided with an additional diaphragm may alternatively have a swing connecting-rod with U packing ring instead of the working diaphragm (16). The additional diaphragm, together with a lateral confinement formed by an intermediate casing (4) of the pump case (2), composes an essentially closed diaphragm interspace. A deformable annular zone (30) of the additional diaphragm (26) has a channel-like convexity (31) which, in the undeformed condition of the diaphragm, points in the direction of the eccentric drive (7). For this purpose, the elastically deformable annular zone (30) of the additional diaphragm (26) has a radial expanse wider than the deformable annular zone (24) of the working diaphragm (16). When, for instance, the diaphragm/U packing ring interspace (29, 129) is evacuated, contamination of the pumped medium by the contents of the diaphragm/U packing ring interspace (29, 129) is largely prevented in case of damage to the working diaphragm (16)/U packing ring (143).
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