Liquid purification or separation – With means to add treating material
Reexamination Certificate
2000-05-17
2001-12-11
Lithgow, Thomas M. (Department: 1724)
Liquid purification or separation
With means to add treating material
C210S748080, C210S205000, C210S256000, C210S259000, C210S407000, C422S186300
Reexamination Certificate
active
06328884
ABSTRACT:
The invention relates to a device for sterilizing and filtering water flowing through a sanitary appliance, having
a) a housing, which comprises an inlet and an outlet for the water;
b) a filtering apparatus, which is disposed in the housing and through which the water travelling between the inlet and the outlet of the housing has to flow;
c) a UV lamp, which is disposed inside the housing and the radiation of which is directed towards the water flowing through and towards the filtering apparatus.
In recent years the dangers arising in the field of sanitation from water contaminated with micro-organisms, in particular bacteria, amoebae or other monocellular organisms, have become ever clearer. For said reason, increased importance is being attached to water sterilization. In said connection, there have been reports of experiments to sterilize flowing water through exposure to UV light, which is of a wavelength suitable for killing micro-organisms carried along in the water. To extend the retention time of said micro-organisms in the region of the UV lamp, use was made of filtering apparatuses, by which the micro-organisms were retained. The known filtering apparatuses however comprised solid substances and had a relatively low efficiency. After only slight penetration into the material of said filtering apparatuses the monocellular organisms were no longer accessible to the UV light. What is more, said known filtering apparatuses considerably restricted the water flow.
The object of the present invention is to indicate a device of the type described initially, which improves the efficiency of the filtering operation itself and the effectiveness of sterilization by means of UV radiation.
Said object is achieved according to the invention in that the filtering apparatus comprises:
d) a filter cloth bag made of knitted or woven plastic material which transmits, in particular guides, UV light;
e) a supporting cage, which lends the filter cloth bag a specific shape and is likewise made of a plastic material which transmits, in particular guides, UV light,
wherein
f) the filtering apparatus surrounds the luminous element of the UV lamp.
The present invention therefore brings together two ideas: firstly, the filter material no longer comprises solid substances, which for their mechanical stability have to have a considerable minimum thickness and moreover provide a relatively small effective filtering surface, but a knitted or woven plastic cloth. The supporting cage provided according to the invention lends said cloth such a shape that it may surround the entire luminous element of the UV lamp. The filter cloth may be relatively thin; it is light and mechanically stable and is optionally also exchangeable without difficulty. The second inventive idea, by means of which the effectiveness of the UV radiation is markedly further improved, lies in making the material, from which the filter cloth bag and the supporting cage are made, capable of transmitting the light emitted by the UV lamp. This has the advantage that even micro-organisms lying deeper in the filter cloth may be reached and killed by the UV light. Given a suitable selection of material, it is even possible to achieve the effect whereby filter cloth bag and supporting cage serve as a “light guide” for the light emitted by the UV lamp, which guides said light in a concentrated manner into the regions of the filtering apparatus which are more remote from the UV lamp.
It is advantageous when the filter cloth bag is folded a plurality of times in radial direction. By said means the effective filtering surface is further increased, which extends the retention time and reduces flow restriction.
Particularly preferred in said case are embodiments, in which the filter cloth bag is composed of individual webs, which at their edges directed towards one another are two-dimensionally connected to one another in such a way that the end faces are exposed and point towards the luminous element of the UV lamp. In said case, the light emitted by the UV lamp may namely enter at the end faces highly effectively into the material of the filter cloth bag.
A possible refinement of the supporting cage is such that it comprises a plurality of radially aligned ribs, which at one end are connected in a cupola-like manner to one another and against the internal contours of which the filter cloth bag is supported. In said manner, a highly stable formed body is inexpensively produced, which may optionally be easily removed from the device for the purpose of exchange.
The ribs should have an internal contour which at least over a specific distance extends parallel to the luminous element of the UV lamp. It is thereby guaranteed that all of the material of the filter cloth bag fastened to the internal contour of the ribs is easily reached by the UV light.
An alternative refinement of the supporting cage is such that it is formed from rod-like material.
It is least expensive when the supporting cage is formed from plastic ropes, which are stretched over a part situated in the housing. The supporting cage is in said case no longer dimensionally stable from the start but receives its “bearing” or “supporting” function only when the ropes are stretched after installation of the filtering apparatus inside the housing of the device.
It is particularly advantageous in terms of cost when the actual part, which is situated in the housing and over which the plastic ropes are stretched, is the luminous element of the UV lamp. In said manner, the entire filtering apparatus is adapted without special additional measures to the shape of the UV lamp.
Particularly advantageous in terms of assembly is the refinement of the filtering apparatus, in which the filter cloth bag is fastened to the supporting cage by means of fastening clips. Said embodiment optionally also enables an exchange of the filter cloth bag alone when the latter, after a specific operating period, is totally clogged with impurities.
REFERENCES:
patent: 3551091 (1970-12-01), Veloz
patent: 4694179 (1987-09-01), Lew et al.
patent: 4766321 (1988-08-01), Lew et al.
patent: 5529689 (1996-06-01), Korin
Hansa Metallwerke AG
Lithgow Thomas M.
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