Membrane system, membrane, and a metering diaphragm pump

Abstract

The present invention also relates to a metering diaphragm pump with a membrane system of the type described, or with a corresponding membrane, where the membrane is clamped at its outer section, and the metering diaphragm pump has a cavity that is divided by the membrane into a metering chamber and a working chamber. An actuator is provided, which moves the core back and forth between the first and second positions. Through the inventive measures, the metering diaphragm pump can be designed so that the ratio of the outer diameter of the flexing section to the distance between the first and second positions of the core is less than 15, preferably less than 12.5, particularly preferably less than 10 and greater than 5.

1 . A membrane system for a metering pump comprising a membrane, comprising: an outer section intended to be clamped, a central section, and a flexing section surrounding the central section, which connects both the outer section and the central section, wherein the flexing section is designed to allow the central section to move back and forth relative to the outer section between a first position and a second position along a longitudinal axis, wherein the membrane has a first side intended to come into contact with a dosing fluid, and a second side not intended to come into contact with the dosing fluid, as well as a core that rests against the second side at the central section, wherein the membrane has a fastening section located on the second side, and a clamping piece is provided, wherein the core, fastening section, and clamping piece are arranged and designed such that the fastening section is held between the core and the clamping piece, characterized in that a support element with a support surface is provided, wherein the support surface is in contact with the second side of the membrane in the area of the flexing section in the second position and is not in contact with the second side of the membrane in the area of the flexing section in the first position. 
     
     
         2 . The membrane system according to  claim 1 , characterized in that the support surface is arranged on the clamping piece, wherein preferably the core has a section with external threading and the clamping piece is screwed onto the external threading. 
     
     
         3 . The membrane system according to  claim 1 , characterized in that the support surface is at least partially made of an elastic material, or a plastic, an elastomer, or EPDM or NBR. 
     
     
         4 . The membrane system according to  claim 1 , characterized in that the support surface is convexly curved. 
     
     
         5 . The membrane system according to  claim 3 , characterized in that the core is at least partially convexly curved on the side resting against the central section, and optionally wherein at least a section facing the support surface is convexly curved. 
     
     
         6 . The membrane system according to  claim 5 , characterized in that the sum of the curvature radius of the support surface and the membrane thickness at the section in contact with the support surface, and the sum of the curvature radius of the convexly curved section of the core and the membrane thickness at the section in contact with the convexly curved section of the core, are substantially equal. 
     
     
         7 . The membrane system according to  claim 5 , characterized in that the membrane has a thickness d R  at an edge of the central section and a thickness d S  at the section in contact with the support surface in the second position, wherein in a sectional view, at least one edge of the central section and an imaginary line spaced from the support surface by the difference |d S −d R | run along a continuous and inflection-free section of a mathematical function. 
     
     
         8 . The membrane system according to  claim 1 , characterized in that the support surface is rotationally symmetrical. 
     
     
         9 . The membrane system according to  claim 1 , characterized in that the fastening section is located at a boundary between the central section and the flexing section. 
     
     
         10 . The membrane for a membrane system according to  claim 1 , characterized in that the membrane has two layers separated by a fabric. 
     
     
         11 . The membrane according to  claim 10 , characterized in that the membrane has a protective layer on its second side, which extends over the outer section, the flexing section, and the fastening section, but not over the central section, optionally wherein the protective layer rests against the second side of the membrane, at least in the area where the protective layer may come into contact with the support surface, in both the first and second positions, but is not bonded to it. 
     
     
         12 . The membrane according to  claim 11 , characterized in that the second side has a groove-shaped recess on the side of the flexing section facing the central section. 
     
     
         13 . The membrane according to  claim 10 , characterized in that the first side of the membrane has a convexly curved section at the transition from the outer section to the flexing section, a convexly curved section at the transition from the central section to the flexing section, and a concavely curved section connecting the two convexly curved sections, optionally wherein a tangent to the inflection point between the convexly curved section positioned at the transition from the outer section to the flexing section and the concavely curved section forms an angle of less than 30° with the longitudinal axis, and/or a tangent to the inflection point between the convexly curved section positioned at the transition from the central section to the flexing section and the concavely curved section forms an angle of less than 65° with the longitudinal axis. 
     
     
         14 . A metering diaphragm pump with a membrane system according to  claim 1 , further comprising a membrane having two layers separated by a fabric, wherein the membrane is clamped at its outer section, the metering diaphragm pump has a cavity that is divided by the membrane into a metering chamber and a working chamber, wherein an actuator is provided that moves the core back and forth between the first and second positions, characterized in that the ratio of the outer diameter of the flexing section to the distance between the first and second positions of the core is less than 15, preferably less than 12.5, particularly preferably less than 10 and greater than 5.