Coated hollow and evacuated insulation spheres (CEIS)
Inventors
Aytug, Tolga • Li, Kai • Lamm, Meghan E. • Hun, Diana • Biswas, Kaushik
Assignees
Publication Number
US-12005414-B2
Publication Date
2024-06-11
Expiration Date
2041-07-23
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Abstract
An insulation medium invention includes a plurality of microspheres. Each microsphere comprises a porous core comprising a porous core material and having an exterior surface, a gas within the porous core, and a coating layer coating all of the exterior surface of the porous core. The coating layer comprises a coating material which transitions from a first state to a second state. In the first state, the coating material is permeable to the gas. In the second state the material is impermeable to the gas. The coating material in the second state is configured to encapsulate and maintain partial vacuum of the gas inside the porous core. In one embodiment, in the second state the coating is impermeable to air. Insulated structures, a method of making an insulation medium, a fluid storage media, and a method of delivering a fluid are also disclosed.
Core Innovation
The invention discloses an insulation medium comprising a plurality of microspheres. Each microsphere includes a porous core made of a porous core material with an exterior surface, a gas within the porous core, and a coating layer that completely covers the exterior surface of the core. The coating material of this layer is designed to transition from a first state, in which it is permeable to gas, to a second state, in which it becomes impermeable to gas, effectively encapsulating and maintaining a partial vacuum of the gas inside the core. In the second state, the coating is also described as being impermeable to air.
This approach addresses persistent limitations in conventional building insulation materials due to space and technoeconomic constraints, which necessitate slim insulation profiles with low thermal conductivity. Previously, vacuum-insulated panels (VIPs) offered promising results in this area but suffered from fragility and loss of thermal performance over time due to barrier envelope breaches or gas permeation. Alternative core materials, such as aerogels, while possessing advantageous porosity and low thermal conductivity, have high production costs and poor mechanical strength, limiting their practical use.
The core innovation of the patent lies in using microspheres with nanoscale wall porosity and a coating layer that is initially gas-permeable, enabling gas evacuation or loading, and subsequently rendered gas-impermeable to seal the vacuum or contents inside. This system enables the creation of insulation with individually sealed microspheres that offer improved mechanical robustness and adaptability, as damage to one sphere only affects a localized area. Furthermore, the coating transition is compatible with scalable manufacturing techniques and flexible material selection for both core and coating, increasing the practicality for thermal insulation and a range of other uses.
Claims Coverage
There is one independent claim in this patent, which outlines a method for making an insulation medium. The claim encompasses several main inventive features.
Method for making microsphere-based insulation medium with gas-permeable to gas-impermeable coating transition
The method comprises the following main steps: 1. Providing a plurality of microspheres, each having a porous core of a porous core material with an exterior surface. 2. Positioning a gas within the porous core of the microspheres. 3. Applying a coating layer covering all of the exterior surface of the porous core, where the coating material transitions from a first state (permeable to gas) to a second state (impermeable to gas). 4. Applying a vacuum to the coated porous core so that some of the gas diffuses through the coating material in the first state, thereby establishing a partial vacuum in the core. 5. Transitioning the coating material from the first state to the second state while maintaining the partial vacuum inside the core—the coating in the second state seals the core with the partial vacuum within.
The independent claim establishes a method for manufacturing an insulation medium composed of microspheres, each with a porous core and a specially designed coating that transitions from a gas-permeable to a gas-impermeable state, enabling the sealing and maintenance of a partial vacuum within the microspheres. This creates an insulation medium with improved handling and performance characteristics.
Stated Advantages
The invention enables high-quality thermal performance similar to vacuum insulated panels but with significantly improved mechanical robustness, as localized damage affects only a few spheres rather than the entire insulation panel.
The system is flexible for on-site adaptation, as insulation media containing microspheres can be cut to size without sacrificing overall thermal performance.
Manufacturing processes for the invention are based on industry-standard equipment and are inherently scalable, allowing for practical, large-scale production.
Materials used to make the microspheres can be non-toxic, naturally abundant, and inexpensive, increasing the sustainability and affordability of the solution.
Documented Applications
Thermal insulation in buildings, including use in wall panels between surfacing materials such as gypsum, polymers, wood veneers, or engineered woods.
Insulated packaging mediums, using microspheres embedded in matrix materials and enclosed by packaging such as corrugated paper.
Fluid storage media in which microspheres are used to encapsulate and maintain various gases or fluids inside the porous core for later release.
Delivery of biologically active fluid medications to a patient, where the coating degrades at body temperature or in biological fluids to release medication.
Targeted drug delivery, including applications with chemotherapeutic agents for cancer therapy, radiographic contrast agents for imaging, and antimicrobial agents to fight infections.
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