Process for making a ceramic hot gas filter
AssigneeDupont Lanxide Composite, L.P.
InventorsElizabeth Sokolinski Connolly, George Daniel Forsythe, Govindasamy Paramasivam Rajendran
Life of this patent
Estimating the term…
Abstract
A ceramic hot-gas candle filter having a porous support of filament-wound oxide ceramic yarn at least partially surrounded by a porous refractory oxide ceramic matrix, and a membrane layer on the outside surface of the porous support. The membrane layer is formed of an ordered arrangement of continuous filament oxide ceramic yarn which is at least partially surrounded by a porous refractory oxide ceramic matrix. The filter can withstand thermal cycling during backpulse cleaning and is resistant to chemical degradation at high temperatures.
Claims8
A method of making a ceramic hot gas filter comprising:
- (a) fabricating an elongated porous filter support having an outer surface, an opening at one end into a hollow interior, a closed end opposite said open end, an external flange integral with said open end by coating a ceramic oxide support yarn with a first oxide ceramic material, winding said coated ceramic oxide support yarn onto a mandrel to form a plurality of layers of said coated support yarn, each layer being arranged in a criss-crossing relationship with neighboring layers to form a plurality of quadrilateral-shaped openings wherein said winding is controlled to provide dimensions of said quadrilateral shaped openings between about 100 to 500 microns after the heat treatment and said support having an outer surface and openings at its ends into a hollow interior, said mandrel being contoured to provide an external flange as an integral part of said support adjacent one of said openings, said first oxide ceramic material providing, upon heat treatment, a porous refractory oxide support matrix;
- (b) drying the support then removing the mandrel;
- (c) forming a porous membrane layer having a porosity less than that of said support by coating a continuous filament oxide ceramic membrane yarn with a second oxide ceramic material, applying said coated membrane yarn in an ordered arrangement on the outer surface of said support using a method selected from the group consisting of hoop winding, multiple yarn winding, and fabric wrapping, and wherein said second oxide ceramic material providing, upon heat treatment, a porous refractory oxide membrane matrix;
- (d) closing the end of said support opposite said flanged end with an oxide ceramic;
- and
- (e) heat treating said support and said membrane layer.
Dependencies are inferred from the claim text.