Liquid purification or separation – Electrical insulating or electricity discharging
Reexamination Certificate
2001-03-30
2004-06-22
King, Roy (Department: 1742)
Liquid purification or separation
Electrical insulating or electricity discharging
C204S665000, C210S323200, C210S435000, C210S497010, C210S500250, C210S500260
Reexamination Certificate
active
06752925
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
Applicant claims priority under 35 U.S.C. §119 of German Application No. 100 16 006.9 filed on Mar. 31, 2000.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention concerns a filter device to be connected to a conduit for microfiltration and/or ultrafiltration, preferably for varnishes, such as cathodic dipping varnishes, having a pressure housing and at least one ceramic membrane filter element located in the pressure housing. The present invention further concerns a process for microfiltration and/or ultrafiltration of fluids to be filtered using at least one filter device of the type previously described.
2. The Prior Art
In practice, filter devices for microfiltration and ultrafiltration of the type initially mentioned are used in many areas. Areas of use are, for example, the filtration of waste water, cleaning solutions, cooling lubricants as from drilling emulsions, and cell separations in high load biology, the concentration of brick engobes, the cleaning of pickling baths, as well as the recycling of swimming pool water. Filter devices of the type initially mentioned are also used in the chemical and biochemical industries for cell separation, protein filtration, dye filtration, catalyst reclamation, and purification of photochemical developing solutions. Furthermore, these types of filter devices are also used in the food industry, for example, in the filtration of sediment from beer, in the clarifying filtration of sugar syrup, fruit juice, wine, and vinegar, in the defatting of whey, and in lactoferrin filtration.
Filter devices of the type initially mentioned are not typically used in the area of varnish recycling, particularly of cathodic dipping varnishes which are used in the varnishing of motor vehicle parts. This is because it has become known that ceramic membrane filter elements clog relatively quickly, so that economical recycling of varnish with filter devices of the type under discussion is currently not possible. For these reasons, filter devices with polymer filters are typically currently used for the recycling of cathodic dipping varnishes.
However, it is problematic that polymer filters have a comparatively low operational capacity when used for the recycling of cathodic dipping varnishes. Due to the comparatively low operational capacity, very large filter areas are required to be able to process large amounts of fluids to be filtered and/or recycled, which, in turn, requires a relatively large amount of space for a polymer filter facility. A further disadvantage of polymer filter devices when used for cathodic dipping varnish recycling is that the polymer filter elements have a comparatively short service life of between half a year and a year. The polymer filter elements must subsequently be replaced, which requires a corresponding expenditure of work. Furthermore, when polymer filter elements are used in the way described, the polymer filters must be cleaned after shutting down the filter installation for operational reasons, in order to achieve the desired filtration capacity when the installation is started up again. These types of cleanings require increased expenditure of work and time, which is disadvantageous in regard to costs. If cleanings are not performed frequently enough or cleaning is unintentionally forgotten, the function of the entire installation can be significantly impaired.
SUMMARY OF THE INVENTION
An object of the current invention is therefore to provide a filter device of the type initially mentioned which is also suitable for the recycling of varnishes, particularly cathodic dipping varnishes.
The previously described object is essentially achieved, according to the invention, by a filter device of the type mentioned initially, in that a ceramic membrane filter element is electrically connected with at least one electrical conductor and is grounded via the electrical conductor. According to the method, it is provided that the fluid to be filtered is at least partially discharged before and/or during the filtration.
Surprisingly, it has been determined that, in the application of the invention, it is possible to recycle cathodic dipping varnishes economically with ceramic membrane filter elements without anything further being necessary. Other fluids having a charged state during filtration can also henceforth be filtered and/or recycled. The result according to the invention was surprising because the previous impression was that filter devices were, in practice, always grounded in any case. However, it has been determined using precise tests that, due to the nonconducting seals and buffers used, the pressure housings of the individual filter devices do not have sufficient grounding in and of themselves. Even with sufficient grounding of the pressure housing alone, the effect according to the invention could not be detected to the same degree occurring when the individual ceramic membrane filter elements are grounded. It is inferred from this that the effect according to the invention, namely the conductance of charges via the grounding, must occur directly at the location at which the filtration also occurs, namely at the ceramic membrane filter element itself. Furthermore, it is inferred from this that conductance of charges possibly present on the membrane surface of the ceramic membrane filter element itself also occurs due to the implementation according to the invention. In any case, the conductance of charges through the grounding of the ceramic membrane filter element keeps the individual molecules and/or ions of the fluid to be filtered from accumulating on the surface of the ceramic membrane filter elements and clogging the filter element in this way.
The advantages achievable with the invention are, in any case, convincing. Due to the significantly higher operational capacity, filter devices with ceramic membrane filter elements, which require significantly less space for the same operational capacity, can now also be used where previously only polymer filters could be used. Furthermore, it has been determined that the invention makes it possible, without anything further, to lengthen the intervals between cleaning of the filter device according to the invention, and/or not perform any cleaning at all over a long period of time, without this having disadvantageous effects on the degree of effectiveness of the installation. In addition, when ceramic membrane filter elements of the type according to the invention are used, the installation can be immediately started up again after it is shut down, i.e. no stripping or cleaning must be performed, which also contributes to improvement of the operational and/or functional reliability of the installation.
In a structurally simple development according to the invention, the pressure housing and/or the conduit which is connected to the filter device consists of an electrically conductive material, while the ceramic membrane filter element is connected via the electrical conductor with the pressure housing and/or the conduit. The grounding then occurs via the pressure housing and/or the conduit. Basically, it is, of course, also possible to lead the conductor as such out of the pressure housing and ground it directly.
In a particularly simple development of the present invention, the conductor is formed as a component separate from the pressure housing, preferably a wire, which electrically connects the pressure housing and/or the conduit with the ceramic membrane filter element. The use of a wire represents a very simple and economical development of a conductor which can also be realized as a supplement to existing installations at low cost, without anything further being necessary.
Particularly good filtration results are realized in this respect if the conductor is inserted in a through hole of the ceramic membrane filter element and extends at least over essentially the entire length of the through hole. In this way, a conductance of charges over the entire length of the ceramic membrane filter element is possi
Atech Innovations GmbH
Collard & Roe P.C.
King Roy
Leader William T.
LandOfFree
Filter device with an electrically grounded ceramic membrane... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Filter device with an electrically grounded ceramic membrane..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Filter device with an electrically grounded ceramic membrane... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3354650