Membrane Level Sensor for Sewage Lifting Reliability
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Solution Overview
Problem
Sewage lifting plants face reliability issues due to contamination impairing the functionality of level sensors used to switch pumps on and off, as these sensors come into contact with wastewater, leading to potential electrical and mechanical component damage.
Innovation Solution
A membrane-based level sensor design where the sensor and switch components are housed within a sealed membrane housing, with a movable membrane that deforms under water pressure to activate the pump, keeping electrical components protected from contamination and moisture, and allowing for easy maintenance and replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a level sensor is arranged in the container to detect water level and switch the pump on and off, then the pump can be switched on and off as required, but the level sensor can be impaired in its function by contaminants carried along in the sewage
Solution Approach 1:
The level sensor is segmented into two distinct parts: a sealed sensor housing containing the electrical components that remains outside the wastewater, and a membrane that interfaces with the wastewater. This segmentation allows the sensor to function in the harsh environment without contaminating the sensitive electrical components.
Solution Approach 2:
A membrane acts as an intermediary between the wastewater and the sensor components. The membrane transmits pressure information from the wastewater to the sensor while preventing direct contact between contaminants and the electrical components, thus mediating the interaction between the harsh environment and the sensitive sensor.
2Measurement precision
If the level sensor components are exposed to wastewater for direct detection, then the sensor can detect water level accurately, but electrical and mechanical components come into contact with waste water leading to contamination and potential damage
Solution Approach 1:
A flexible membrane serves as a protective shell that allows pressure transmission while blocking contaminants. The membrane is thin enough to be responsive to pressure changes for accurate level detection, yet provides sufficient protection to prevent contamination of the electrical components inside the sealed housing.
Solution Approach 2:
The electrical and mechanical components are extracted from the wastewater environment and placed inside a sealed sensor housing. Only the membrane remains in contact with the wastewater, extracting the harmful exposure away from the sensitive components while maintaining detection functionality.
3Reliability
If a sealed membrane housing is used to protect sensor components from wastewater, then electrical components are protected from contamination and moisture, but the membrane housing displaces part of the liquid causing pressure on the membrane
Solution Approach 1:
The patent replaces direct mechanical contact between sensor components and wastewater with a pressure transmission system. The membrane converts mechanical pressure from the wastewater into a form that can actuate the sensor inside the sealed housing, substituting the need for direct mechanical exposure with a pressure-based signaling mechanism.
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
The solution provides a robust and reliable level sensing mechanism that is resistant to contamination and moisture, ensuring consistent operation of the sewage lifting plant by isolating sensitive components from wastewater, thereby enhancing operational reliability.
Implementation Method 1
pressure is exerted from the outside on the membrane housing and thus the membrane by the waste water, which pressure leads to a movement or deformation of the movable membrane
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The sewage lifting unit a container (2), a pump (6) provided in the container and a liquid level sensor (14). The liquid level sensor in fully closed state is arranged in the membrane container housing which comprises a movable diaphragm. The membrane diaphragm in the interior of the housing comprises a switch which switches ON and OFF the pump. The membrane diaphragm is arranged on the lower side of the diaphragm housing.