Membrane Cover Gas Passage Pressure Equalization
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Solution Overview
Problem
Floating membrane covers on large industrial, municipal, and agricultural reservoirs face issues with gas pocket formation due to wind-induced forces and water accumulation, leading to membrane fatigue and potential rupture, despite previous solutions failing to entirely prevent puddle formation and flap-valve attachment conditions.
Innovation Solution
A method involving periodic pressure equalization in the gas passage under the membrane and a stiff, turbulence-inducing membrane structure to break flap-valve attachment conditions, allowing bio-gases to migrate and reducing adhesion forces between the membrane and liquid surface, combined with a stiffened and rough-surfaced membrane to prevent flexing and enhance gas flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If weight lines and drains are used to reduce water puddles, then water drainage is improved, but gas pocket formation and flap-valve attachment conditions persist
Solution Approach 1:
The patent applies periodic action by alternating between positive pressure application (to break flap-valve attachment and release gas pockets) and negative pressure maintenance (to contain bio-gases). This periodic pressure cycling prevents permanent attachment conditions while maintaining gas containment, resolving the contradiction between water drainage and gas pocket formation.
Solution Approach 2:
The patent changes the pressure parameter dynamically - switching between positive pressure (atmospheric or higher) to break attachment conditions and negative pressure to maintain gas containment. This parameter change allows the system to address both water drainage and gas pocket issues without compromise.
2Reliability
If negative pressure is applied to contain bio-gases, then gas containment is improved, but flap-valve attachment conditions worsen
Solution Approach 1:
The system periodically applies positive pressure to break flap-valve attachment conditions, then returns to negative pressure for gas containment. This periodic switching allows the membrane to be freed from attachment conditions while maintaining effective gas containment during the negative pressure phase.
Solution Approach 2:
Positive pressure is applied in advance (pre-action) to break flap-valve attachment conditions before the negative pressure phase begins. This preliminary action prevents the attachment conditions from developing during the subsequent gas containment operation.
3Duration of action of stationary object
If membrane is made stiff to prevent flexing, then membrane durability is improved, but gas flow migration is hindered
Solution Approach 1:
The patent uses periodic positive pressure application to temporarily overcome the stiffness-induced resistance to gas flow. During these periodic intervals, the pressure differential is sufficient to force gas migration through the stiff membrane, maintaining both durability and productivity.
Solution Approach 2:
The system maintains continuous gas flow migration by alternating pressure phases - when positive pressure is applied, gas flows freely; when negative pressure is applied, gas flow continues but at reduced rate. The continuous cycling ensures uninterrupted gas migration while preserving membrane stiffness.
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
Effectively reduces gas pocket formation, extends membrane life by preventing flap-valve attachment and reducing wind-induced stresses, allowing efficient bio-gas migration and rainwater drainage, thereby enhancing the durability and functionality of the membrane cover.
Implementation Method 1
the capillary effect between the membrane cover and the liquid surface inside the reservoir
Implementation Method 2
the capillary effect between the membrane cover and the liquid surface inside the reservoir
Implementation Method 3
periodically and momentarily increasing a pressure in the gas passage under the membrane cover to equal or to slightly exceed a pressure in the accumulation of bio-gases
Data Source
AI summary
In a covered wastewater reservoir, a gas passage is defined under the membrane cover and along the sides of the reservoir. An accumulation of bio-gases is held captive between the membrane cover and the liquid surface in a central region of the reservoir relative to the gas passage, by a flap-valve attachment condition extending between the accumulation of bio-gases and the gas passage. The new method for breaking this flap-valve attachment condition and for allowing bio-gases to flow from the accumulation of bio-gases toward the gas passage, consists of periodically and momentarily increasing a pressure in the gas passage to equal or to slightly exceed a pressure in the accumulation of bio-gases. In another aspect, the membrane cover is provided with a stiff and rough-surfaced bottom layer to facilitate the breaking of flap-valve attachment conditions when the pressure under the cover is made equal everywhere.