Expandable Polymeric Microsphere Expansion Apparatus
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Solution Overview
Problem
The cementitious composition industry faces challenges in stabilizing and controlling air voids in concrete to prevent freeze-thaw damage, as conventional air-entraining agents are inefficient and costly, particularly due to high shipping expenses associated with expanded polymeric microspheres.
Innovation Solution
An apparatus that consumes less energy and is smaller in size, utilizing a steam generator with a power output of less than 6 boiler horsepower to expand polymeric microspheres, which are then used to create controlled-size voids in cementitious compositions, reducing shipping costs and improving durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional air-entraining agents are used to create air voids in cementitious compositions, then freeze-thaw resistance is improved, but air content control becomes difficult and compressive strength may be reduced
Solution Approach 1:
The invention changes the physical state and properties of the air-entraining agent by using expandable polymeric microspheres that undergo phase transition from collapsed to expanded state. This allows precise control of air void characteristics through parameters such as expansion ratio, sphere size, and expansion timing, rather than relying on unstable air bubble formation
Solution Approach 2:
The invention replaces the chemical-mechanical system of air-entraining surfactants with a purely mechanical expansion system. The polymeric microspheres are mechanically expanded from a collapsed transport state to an expanded functional state within the cementitious composition, eliminating the need for chemical surfactant stabilization
2Manufacturing precision
If expanded polymeric microspheres are used to create controlled voids, then void size control is improved, but shipping costs increase due to high-volume expanded form
Solution Approach 1:
The invention applies the nesting principle by placing the expanded polymeric microspheres in a collapsed or compressed state during shipping and storage. The microspheres are nested within each other or compressed into dense packs, reducing shipping volume by a factor of 5-10 times compared to the expanded state. Expansion to the final void-forming state occurs only after incorporation into the cementitious composition
Solution Approach 2:
The invention applies preliminary action by pre-manufacturing the polymeric microspheres in a collapsed transport form that is stable for storage and shipping. The expansion to the functional void-forming state is triggered preliminarily only when and where needed, after the microspheres are incorporated into the cementitious composition, thereby avoiding the shipping volume penalty of the expanded state
3Productivity
If a large apparatus is used to expand polymeric microspheres, then expansion capability is improved, but energy consumption and apparatus size increase
Solution Approach 1:
The invention applies self-service by using the exothermic hydration heat naturally generated during cementitious composition setting to provide the thermal energy required for microsphere expansion. The cementitious composition itself serves as the heat source, eliminating the need for external high-power heating apparatus. The expansion occurs autonomously as the composition cures and generates heat
Solution Approach 2:
The invention exploits phase transitions of the polymeric microsphere material, specifically the transition from a collapsed glassy or crystalline state to an expanded rubbery or amorphous state. This phase transition occurs at a specific temperature threshold that can be reached through the moderate heating provided by cement hydration, allowing expansion capability without requiring high-power external heating equipment
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 apparatus efficiently expands polymeric microspheres, providing enhanced freeze-thaw durability and reduced material costs by minimizing energy consumption and apparatus size, allowing for more effective void creation in cementitious compositions without the need for extensive air bubble stabilization during mixing.
Implementation Method 1
utilizing a steam generator with a power output of less than 6 boiler horsepower to expand polymeric microspheres
Implementation Method 2
a back pressure generator in fluid communication with the treatment zone, capable of increasing pressure in the treatment zone, which results in expansion of the expandable polymeric microspheres when the fluid material exits the treatment zone
Data Source
Figure 1
Figure 2
AI summary
An apparatus including: (a) a steam generator having a power output of less than or equal to about 6 boiler horsepower; (b) a steam conduit in fluid communication with the steam generator; (c) a fluid material conduit in fluid communication with a source of a fluid material, wherein the fluid material includes unexpanded, expandable polymeric microspheres; (d) a treatment zone in fluid communication with the steam generator via the steam conduit, and with the fluid material conduit, such that the fluid material is contacted by steam within the treatment zone; and (e) a back pressure generator in fluid communication with the treatment zone, capable of increasing pressure in the treatment zone, which results in expansion of the expandable polymeric microspheres when the fluid material exits the treatment zone.