Protective Membrane Layout for Diaphragm Pump Rupture Control
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Solution Overview
Problem
Metering diaphragm pumps face premature membrane rupture due to alternating tensile and compressive stress, leading to fluid leaks and limited operational scope, especially when using hydraulic drives with single-layer metal membranes.
Innovation Solution
Incorporating a protective membrane next to the metering membrane, made of a different material, to seal the working chamber in case of rupture, while maintaining the movement characteristics of the metering membrane, and using a pretensioned elastic metering membrane to minimize stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-layer metering membrane is used, then the membrane can be made elastic and move back to the second position without additional springs, but the membrane is susceptible to rupture due to alternating tensile and compressive stress
Solution Approach 1:
The single-layer membrane is divided into two separate membranes: a metering membrane for active pumping and a protective membrane for reliability. This segmentation allows each membrane to be optimized for its specific function while working together as a system.
Solution Approach 2:
The protective membrane is positioned adjacent to the metering membrane to provide a backup seal before the metering membrane fails. This preemptive measure prevents fluid leakage even when the metering membrane ruptures due to alternating stress.
2Reliability
If a multi-layer metering membrane is used to detect rupture, then leak detection is enabled, but the additional layers impede the movement of the metering membrane
Solution Approach 1:
The detection function is separated from the movement function by placing a distinct protective membrane adjacent to the metering membrane. This allows the metering membrane to move freely while the protective membrane provides leak detection capability.
Solution Approach 2:
The protective membrane acts as an intermediary element between the metering membrane and the environment. It detects leaks by becoming displaced when the metering membrane ruptures, without interfering with the metering membrane's normal movement.
3Reliability
If the metering membrane is pretensioned in one direction, then alternating tensile and compressive stress is eliminated and service life is improved, but the membrane requires additional tensioning mechanisms
Solution Approach 1:
The metering membrane's own elasticity is utilized to provide the restoring force for return movement, eliminating the need for additional spring elements or complex tensioning mechanisms. The membrane serves itself by leveraging its material properties.
4Ease of operation
If a hydraulic drive is used, then the metering membrane can be moved easily in one direction, but the pump requires a minimum suction pressure to ensure reliable return movement
Solution Approach 1:
The return movement function is extracted from the hydraulic drive system and assigned to the elastic restoring force of the metering membrane. This eliminates the dependency on minimum suction pressure for return movement, expanding the pump's application scope.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances membrane durability and leak detection, allowing operation with low fluid pressure and preventing fluid contamination, even in the absence of pressure differences.
Implementation Method 1
Due to the elasticity of the metal foil, the membrane can itself move back to the second position to a certain extent without the need for a corresponding drive or additional spring elements
Implementation Method 2
a protective membrane which is disposed next to the metering membrane on the working chamber side
Data Source
AI summary
A metering diaphragm pump includes a metering chamber, a working chamber and a metering membrane. The metering chamber and the working chamber are separated from one another by the metering membrane. A device for moving the metering membrane back and forth between a first and a second position is provided. The volume of the metering chamber is smaller in a first position than in the second position, and a protective membrane is disposed next to the metering membrane on the working chamber side.