Expanded polymer material for cryogenic applications apparatus and method
OwnerThomas M. Golner, Shirish P. Mehta +1inventors
InventorsThomas M. Golner, Shirish P. Mehta, Edward F. Pleva
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Abstract
A structural and insulating material for cryogenic power transformers uses nonwoven fibers, such as polyester matting, embedded within epoxy made highly porous with a blowing agent. The open cell foam of the material is characterized by controlled pore size and density, tolerance of extreme thermal gradients, and strength at cryogenic temperatures, and is selected for compatibility with dielectric fluids such as liquid nitrogen and cryogenic blends.
Claims22
A porous structural material for immersion in a dielectric cryogenic fluid, comprising:
- a matrix of fibers comprising a first organic polymer, wherein the fibers are compatible with being subjected to power transmission field gradients in a cryogenic environment;
- an epoxy that wets the fiber matrix substantially completely, and that forms a second organic polymer in the course of a curing process, wherein the epoxy is compatible with being subjected to power transmission field gradients in a cryogenic environment;
- and
- an interconnected pore structure within the epoxy, wherein a blowing agent establishes the pore structure within the epoxy-wetted fiber matrix as a part of the curing process, and wherein the pore structure allows a specified extent of flow of a cryogenic fluid through a porous composite cryogenic structural material established by the curing process.
Apparatus for producing porous structural material for immersion in a dielectric cryogenic fluid, comprising:
- a mold having a mold cavity configured to constrain constituents to a defined shape during formation of a cryogenic structural component;
- at least one mold inlet port configured to admit a hardenable fluid constituent, comprising a blowing agent, into the mold cavity, wherein the hardenable fluid constituent is compatible with exposure to cryogenic fluids and temperatures after hardening;
- injection apparatus configured to urge the hardenable fluid constituent into the mold cavity;
- at least one mold outlet port configured to vent the mold cavity during filling the mold cavity with the hardenable fluid constituent, forming interconnected pores within the hardenable fluid constituent by a blowing gas released from the blowing agent, or curing of the hardenable fluid constituent at least in part within the mold;
- and
- an environment regulator configured to provide a specified extent of control over temperature or pressure within the mold cavity.
A porous structural material for immersion in a dielectric cryogenic fluid, comprising:
- means for providing mechanical strength to a cryogenic structural material;
- means for binding the means for providing mechanical strength into a solid mass, wherein the means for binding is compatible with exposure to cryogenic environments;
- and
- means for introducing a matrix of interconnected pores within the means for binding.
A process of forming a porous structural material for immersion in a dielectric cryogenic fluid, comprising:
- placing at least one precut mat of nonwoven fibers within a cavity of a mold;
- closing the mold to an extent sufficient to define a specific cavity interior volume and shape and to seal the cavity against uncontrolled outflow of fluids;
- injecting an epoxy mixture that includes a blowing agent into the cavity through at least one mold inlet port;
- venting gases from the cavity through at least one mold outlet port;
- and
- regulating mold temperature and pressure throughout a cryogenic structural material forming process to an extent sufficient to ensure wetting the fibers, curing the epoxy at least in part, and forming interconnected pores with a specified distribution throughout a cryogenic structural material compatible with immersion and saturation in a cryogenic dielectric fluid.
Dependencies are inferred from the claim text.