Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Clay or inorganic aluminosilicate salt component
Reexamination Certificate
2000-09-19
2003-10-21
Boyer, Charles (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Clay or inorganic aluminosilicate salt component
C510S195000, C510S199000, C510S436000, C510S467000, C510S485000, C510S510000, C510S534000
Reexamination Certificate
active
06635613
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
In one of its aspects, the present invention relates to a cleaning formulation for, inter alia, optical surfaces. In another of its aspects, the present invention relates to method for removing fouling materials, inter alia, from an optical surface.
2. Description of the Prior Art
Fluid treatment systems are known generally in the art.
For example, U.S. Pat. Nos. 4,482,809, 4,872,980 and 5,006,244 (all in the name of Maarschalkerweerd and all assigned to the assignee of the present invention and hereinafter referred to as the Maarschalkerweerd #1 Patents) all describe gravity fed fluid treatment systems which employ ultraviolet (UV) radiation.
Such systems include an array of UV lamp frames which include several UV lamps each of which are mounted within sleeves which extend between and are supported by a pair of legs which are attached to a cross-piece. The so-supported sleeves (containing the UV lamps) are immersed into a fluid to be treated, which is then irradiated as required. The amount of radiation to which the fluid is exposed is determined by factors such as: the proximity of the fluid to the lamps, the output wattage of the lamps, the fluid's flow rate past the lamps, the UV transmission (UVT) of the water or wastewater, the percent transmittance (%T) of the sleeves and the like. Typically, one or more UV sensors may be employed to monitor the UV output of the lamps and the fluid level is typically controlled, to some extent, downstream of the treatment device by means of level gates or the like.
However, disadvantages exist with the above-described systems. Depending upon the quality of the fluid which is being treated, the sleeves surrounding the UV lamps periodically become fouled with foreign materials, inhibiting their ability to transmit UV radiation to the fluid. For a given installation, the occurrence of such fouling may be determined from historical operating data or by measurements from the UV sensors. Once, or before fouling occurs, the sleeves must be cleaned to remove the fouling materials and optimize system performance.
If the UV lamp modules are employed in an open, channel-like system (e.g., such as the one described and illustrated in Maarschalkerweerd #1 Patents), one or more of the modules may be removed while the system continues to operate, and the removed frames may be immersed in a bath of suitable cleaning solution (e.g., a mild acid) which may be air-agitated to remove fouling materials. Of course, this necessitates the provision of surplus or redundant sources of UV radiation (usually by including extra UV lamp modules) to ensure adequate irradiation of the fluid being treated while one or more of the frames has been removed for cleaning. This required surplus UV capacity adds to the capital expense of installing the treatment system. Further, a cleaning vessel for receiving the UV lamp modules must also be provided and maintained. Depending on the number of modules which must be serviced for cleaning at one time and the frequency at which they require cleaning, this can also significantly add to the expense of operating and maintaining the treatment system. Furthermore, this cleaning regimen necessitates relatively high labour costs to attend to the required removal/re-installation of modules and removal/re-filling of cleaning solution in the cleaning vessel. Still further, such handling of the modules results in an increased risk of damage to or breakage of the lamps in the module.
If the frames are in a closed system (e.g., such as the treatment chamber described in U.S. Pat. No. 5,504,335 (in the name of Maarschalkerweerd and assigned to the assignee of the present invention) removal of the frames from the fluid for cleaning is usually impractical. In this case, the sleeves must be cleaned by suspending treatment of the fluid, shutting inlet and outlet valves to the treatment enclosure and filling the entire treatment enclosure with the cleaning solution and air-agitating the fluid to remove the fouling materials. Cleaning such closed systems suffers from the disadvantages that the treatment system must be stopped while cleaning proceeds and that a large quantity of cleaning solution must be employed to fill the treatment enclosure. An additional problem exists in that handling large quantities of cleaning fluid is hazardous and disposing of large quantities of used cleaning fluid is difficult and/or expensive. Of course open flow systems suffer from these two problems, albeit to a lesser degree.
Indeed, once installed, one of the largest maintenance costs associated with prior art fluid treatment systems is often the cost of cleaning the sleeves about the radiation sources. U.S. Pat. Nos. 5,418,370, 5,539,210 and 5,590,390 (all in the name of Maarschalkerweerd and all assigned to the assignee of the present invention and hereinafter referred to as the Maarschalkerweerd #2 Patents) all describe an improved cleaning system, particularly advantageous for use in gravity fed fluid treatment systems which employ UV radiation. Generally, the cleaning system comprises a cleaning sleeve engaging a portion of the exterior of a radiation source assembly including a radiation source (e.g., a UV lamp). The cleaning sleeve is movable between: (i) a retracted position wherein a first portion of radiation source assembly is exposed to a flow of fluid to be treated, and (ii) an extended position wherein the first portion of the radiation source assembly is completely or partially covered by the cleaning sleeve. The cleaning sleeve includes a chamber in contact with the first portion of the radiation source assembly. The chamber is supplied with a cleaning solution suitable for removing undesired materials from the first portion of the radiation source assembly.
In International publication number WO 00/26144 [Pearcey et al. (Pearcey)], published May 11, 2000, there is disclosed a cleaning apparatus for a radiation source module and a radiation source module incorporated such cleaning apparatus. Generally, the cleaning apparatus and related module comprise: (i) a slidable member magnetically coupled to a cleaning sleeve, the slidable member being disposed on and slidable with respect to a rodless cylinder; and (ii) motive means to translate the slidable member along the rodless cylinder whereby the cleaning sleeve is translated over the exterior of the radiation source assembly.
Further improvements to cleaning devices are described in:
copending U.S. patent application Ser. No. 09/258,142 [Traubenberg et al. (Traubenberg)], filed on Feb. 26, 1999;
copending U.S. patent application Ser. No. 60/136,766 [Dall'Armi et al. (Dall'Armi)], filed on May 28, 1999; and
copending U.S. patent application Ser. No. 60/148,648 [Fang et al.(Fang)], filed on Aug. 13, 1999;
each assigned to the assignee of the present invention.
The teachings of Pearcey, Traubenberg, Dall'Armi and Fang each represent important advances in the art, particularly when implemented in a fluid treatment module such as the one illustrated in the Maarschalkerweerd #1 Patents.
One area in the prior art which has received relatively little attention is the nature of the cleaning formulation used in such cleaning devices for optical radiation devices such as the ones taught in the Maarschalkerweerd #2 Patents and in Pearcey, Traubenberg, Dall'Armi and Fang.
It is known that the disinfection efficiency of a UV lamp is dependent on the cleanliness of the surface which houses the UV lamp—see Kreft, P.; Scheible, O.K.; Venosa, A. “HYDRAULIC STUDIES AND CLEANING EVALUATIONS OF ULTRAVIOLET DISINFECTION UNITS”, Journal WPCF, Volume 58, Number 12, p.1129 [Kreft]. Cleaning of a ultraviolet disinfection system is important in order for the system to operate at optimum efficiency. Surface fouling can significantly affect the dose efficiency needed for meeting the disinfection requirements. Fused quartz sleeves, which are conventionally used to house the radiatio
Boyer Charles
Katten Muchin Zavis & Rosenman
Trojan Technologies Inc.
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