Two-Layer Separator Element for Gas-Tight Pressure Accumulators
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Solution Overview
Problem
Existing separator elements in pressure accumulators face challenges in achieving high permeation resistance and media resistance while being cost-effective and durable, as they are prone to delamination and costly to manufacture with complex multilayer structures.
Innovation Solution
A separator element composed of two types of plastic layers, one resistant to mineral oils and the other gas-tight, firmly bonded together to form an elastically flexible structure, with a thin wall thickness to enhance elasticity and prevent delamination, using epichlorohydrin rubber for media resistance and isobutene-isoprene rubber for low gas permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex multilayer structure with many layers is used to achieve high permeation resistance and gas-tightness, then the separator element achieves the desired gas-tightness, but the manufacturing cost increases significantly and delamination risk increases
Solution Approach 1:
The patent applies composite materials by combining two distinct plastic layers with complementary properties: a mineral oil-resistant layer (e.g., NBR, ECO) and a gas-tight layer (e.g., EVOH, PVAc). This composite structure achieves both gas-tightness and media resistance without requiring multiple repetitive layers, thereby reducing overall complexity while maintaining high reliability.
Solution Approach 2:
The separator element is segmented into functionally distinct layers: an outer mineral oil-resistant layer and an inner gas-tight layer. This segmentation allows each layer to specialize in its specific function, achieving high gas-tightness through the dedicated gas-tight layer while the outer layer provides media resistance, avoiding the need for complex multilayer combinations.
2Strength
If a thick wall thickness is used in the separator element to ensure durability and resistance, then the separator element achieves higher strength, but the elasticity decreases
Solution Approach 1:
The patent optimizes the wall thickness parameter to achieve an optimal balance between strength and elasticity. By carefully selecting and controlling the thickness of each functional layer, the separator element maintains sufficient mechanical strength and durability while preserving the elasticity required for flexing movements during accumulator operation.
Solution Approach 2:
The composite structure of two specialized layers provides enhanced strength-to-thickness ratio. The mineral oil-resistant layer provides mechanical strength and durability, while the gas-tight layer provides barrier functionality, allowing the overall wall thickness to be reduced compared to a single-layer design, thereby improving elasticity.
3Device complexity
If a simple two-layer structure is used to reduce manufacturing cost and improve elasticity, then the separator element achieves cost-effective production and better flexibility, but the permeation resistance may be insufficient
Solution Approach 1:
The patent successfully achieves high permeation resistance with only two layers by using composite materials with complementary properties. The EVOH or PVAc layer provides exceptional gas-tightness, while the NBR or ECO layer provides mineral oil resistance. This targeted material selection achieves the required performance with minimal layer count, reducing complexity while maintaining high reliability.
Solution Approach 2:
The patent optimizes material composition parameters and layer thickness ratios to achieve sufficient permeation resistance with a simple two-layer structure. By adjusting the thickness of the gas-tight layer and selecting materials with high barrier properties, the design achieves adequate permeation resistance without requiring additional layers.
4Stability of the object's composition
If multiple impregnating layers and adhesive coatings are applied to prevent delamination, then the bond strength between layers is improved, but the manufacturing process becomes more complex and costly
Solution Approach 1:
The patent uses composite materials with inherent bonding compatibility. The selection of NBR/ECO and EVOH/PVAc layers ensures good adhesion between layers due to their chemical compatibility and surface properties, reducing or eliminating the need for additional adhesive coatings and impregnating layers, thereby simplifying the manufacturing process while maintaining strong bonds.
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 ensures long-lasting, cost-effective production of a separator element with improved elasticity and gas-tightness, preventing unintentional delamination and maintaining functionality in pressure accumulators, particularly in diaphragm accumulators.
Implementation Method 1
the impregnating layers, achieving an intimate, non-detachable bond with consistently high permeation resistance
Implementation Method 2
achieving an intimate, non-detachable bond with consistently high permeation resistance between the gas-tight impregnation and the filaments of the substrate
Implementation Method 3
the process gas stored in the pressure accumulator, such as nitrogen gas, cannot reach the liquid side of the accumulator containing the mineral oil. Otherwise, the nitrogen unintentionally reaches the oil side of the accumulator by first diffusing into the elastomer material of the separator element
Data Source
AI summary
1. Separator element2. A separator element consisting of at least two types of layers of plastic material,one type of which layers is media resistant to mineral oils; andthe other type of which layers has low permeability to gases or is gas-tight,wherein the two types of layers are firmly bonded to each other when in direct contact and form the elastically flexible separator element (12).