Low Temperature High Pressure Rubber Hose Construction
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Solution Overview
Problem
Flexible rubber hoses used in high-pressure applications face challenges in maintaining flexibility at low temperatures while meeting the demands of abrasion resistance and high service pressures, as existing constructions often become stiff and prone to kinking or fatigue.
Innovation Solution
A hose construction featuring an inner tube of nitrile butadiene rubber with a specific elastic modulus and durometer, combined with a chloroprene rubber outer cover, and wire spiral reinforcement, which allows for flexibility at -57°C and resistance to pressures up to 8000 psi, ensuring a strong bond between layers without excessive stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional rubber hose construction is used, then abrasion resistance and high pressure resistance are achieved, but flexibility at low temperatures deteriorates
Solution Approach 1:
The patent applies parameter changes by carefully controlling the elastic modulus and durometer of the nitrile butadiene rubber inner tube. The elastic modulus is maintained between 4.4-8.4 MPa and durometer between 70-80 Shore A, which allows the material to remain flexible at low temperatures while still providing the necessary strength for abrasion and pressure resistance. This precise parameter control resolves the contradiction between strength and low-temperature flexibility.
Solution Approach 2:
The patent uses composite materials by combining nitrile butadiene rubber (NBR) for the inner tube with chloroprene rubber (CR) for the outer cover. The NBR provides oil resistance and structural integrity for pressure containment, while the CR cover provides abrasion resistance and enhanced low-temperature flexibility. This composite construction allows each layer to contribute its superior properties, resolving the contradiction between overall strength and low-temperature flexibility.
2Strength
If rubber hardness is increased for strength, then pressure resistance is improved, but flexibility at low temperatures worsens
Solution Approach 1:
The patent applies parameter changes by precisely controlling the durometer of the NBR inner tube to be between 70-80 Shore A and elastic modulus between 4.4-8.4 MPa. These specific parameter ranges ensure the rubber maintains sufficient hardness for pressure resistance while retaining enough elasticity to remain flexible at low temperatures. The parameter optimization resolves the contradiction between pressure resistance and low-temperature flexibility.
3Strength
If reinforcement layers are added for high pressure, then pressure resistance is improved, but hose stiffness increases
Solution Approach 1:
The patent applies flexible shells and thin films by using a spirally-wound wire reinforcement structure rather than traditional braided or laminated reinforcement. The spiral configuration allows the wire to flex and deform more easily under bending conditions while still providing high pressure containment. This flexible reinforcement approach maintains pressure resistance while minimizing stiffness, resolving the contradiction between pressure strength and operational flexibility.
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 hose construction remains flexible at low temperatures, maintains abrasion resistance, and meets high service pressure requirements, making it suitable for various hydraulic and industrial applications while being economical to manufacture.
Implementation Method 1
an inner tube or core formed of a nitrile butadiene rubber (NBR) or other such rubber compound formulated for low temperature use such as having an elastic modulus (at 100% elongation) of not greater than about 1200 psi (8.4 MPa)
Implementation Method 2
at least a pair of metal or metal alloy wire reinforcement layers are spiral wound to provide resistance to internal working pressures of 4000 psi (28 MPa) or more
Implementation Method 3
the rubber layers and thereby consolidate the construction into an integral hose structure
Implementation Method 4
an outer cover or jacket formed of chloroprene rubber (CR) or other such rubber compound similarly formulated for low temperature use
Data Source
AI summary
Flexible reinforced rubber hose adapted for conveying fluids under low temperatures and high pressures. The hose includes a inner tube formed of an acrylonitrile butadiene rubber (NBR) or other low temperature rubber compound having an elastic modulus of not greater than about 8.4 MPa (1200 psi), and an outer jacket formed of a chloroprene rubber (CR) or other low temperature rubber compound having a durometer of not greater than about 75 Shore A.