Gas separation: processes – Degasification of liquid – By reduction of pressure
Reexamination Certificate
2001-02-13
2003-03-25
Hopkins, Robert A. (Department: 1754)
Gas separation: processes
Degasification of liquid
By reduction of pressure
C096S193000, C055SDIG009, C588S006000
Reexamination Certificate
active
06537350
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Endeavor
The present invention relates to HEPA filers and more particularly to the disposal of HEPA filters.
2. State of Technology
U.S. Pat. No. 5,288,434 for a Hepa filter dissolution process by Brewer et al, patented Feb. 22, 1994, provides the following description, “A process for dissolution of spent high efficiency particulate air (HEPA) filters and then combining the complexed filter solution with other radioactive wastes prior to calcining the mixed and blended waste feed. The process is an alternate to a prior method of acid leaching the spent filters which is an inefficient method of treating spent HEPA filters for disposal.”
U.S. Pat. No. 6,86,365 for a method for dissolution and stabilization of silica-rich fibers by Carol M. Jantzen, patented Nov. 11, 1997 provides the following description, “A method for dissolving silica-rich fibers such as borosilicate fibers, fiberglass and asbestos to stabilize them for disposal. The method comprises (1) immersing the fibers in hot, five-weight-percent sodium hydroxide solution until the concentration of dissolved silica reaches equilibrium and a only a residue is left (about 48 hours), then immersing the residue in hot, five-weight-percent nitric acid until the residue dissolves (about 96 hours). After adjusting the pH of the dissolved fibers to be caustic, the solution can then be added to a waste vitrification stream for safe disposal. The method is useful in disposing contaminated HEME and HEPA filters.”
U.S. Pat. No. 4,613,348 for a disposable HEPA filtration device by Anothy Natale, patented Sep. 23, 1986, provides the following description: “A sealed filtration canister including a filtration mechanism sealed within the canister. A prefilter and a HEPA filter entrap asbestos-containing dust within the sealed canister. Upon usage of the filtration canister for a predetermined number of hours, the canister is disposed of in its entirety. The canister is used in conjunction with a separate vacuum cleaner device having a suction hose communicating with a canister lid removably mounted on top of the canister. Alternately, the canister is used with a portable vacuum motor assembly removably mounted on top of the canister to provide independent suction to the filtration canister.
SUMMARY OF THE INVENTION
The present invention provides the delivery of a low viscosity resin into a spent HEPA filter or other waste. The resin is introduced into the filter or other waste using a vacuum to assist in the mass transfer of the resin through the filter media or other waste. In one embodiment, a vacuum is applied to the resin in a vacuum chamber to remove entrained air. The low viscosity resin is introduced into the spent HEPA filter or other waste by a vacuum or pressure delivery system. Other features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating specific embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description and by practice of the invention.
REFERENCES:
patent: 4585583 (1986-04-01), Roberson et al.
patent: 4613348 (1986-09-01), Natale
patent: 4726825 (1988-02-01), Natale
patent: 4839102 (1989-06-01), Kertesz et al.
patent: 5288434 (1994-02-01), Brewer
patent: 5416251 (1995-05-01), Lomasney et al.
patent: 5686365 (1997-11-01), Jantzen
patent: 3-59499 (1991-03-01), None
Attebery Ronald W.
Bowers John S.
Gates-Anderson Dianne D.
Kidd Scott D.
Hopkins Robert A.
Scott Eddie E.
The Regents of the University of California
Thompson Alan H.
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