Internal-combustion engines – Accessories – Covers – trays – vibrators – corrosion inhibitors – air filters
Reexamination Certificate
2001-07-16
2003-07-29
Kamen, Noah P. (Department: 3747)
Internal-combustion engines
Accessories
Covers, trays, vibrators, corrosion inhibitors, air filters
C055S385300
Reexamination Certificate
active
06598580
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to an insert filter for cleaning a gas stream, which is replaceably positioned in a shaft of a duct system through which the gas stream is guided, and which comprises a filter frame, a filter element supported by the filter frame, and a shaft cover for closing an opening through which the filter is inserted into the shaft.
A filter, accommodated by an adapter, which is inserted in a shaft of a channel of a ventilation or air-conditioning unit is known from DE 42 34 047. The shaft is closed with a cover and clamped with clamps. The clamps can be displaced on locking bars. The locking bars are located both on the cover and on the channel. The filter has a filter frame, three sides of which are inserted in the shaft, with the cover forming the fourth side of the filter frame and also being inserted in the shaft. The shaft is constructed in such a way that it tapers continuously beginning at an insertion side, so that the force necessary to insert the filter is low and seals only come to bear against the filter when it is completely installed. The seals, which lie opposite the insertion side, are pressed firmly against the shaft when the cover is locked with the shaft.
To remove the filter from the shaft, the clamps must first be pushed aside. Subsequently, a pull is necessary, which pulls the filter out of the shaft. However, in order to transmit this pull to the filter, an additional removal aid is necessary because the cover itself is not positioned in the shaft in such a way that it can be readily grasped. This removal aid is thus absolutely necessary for every replacement of the filter. The use of an additional removal aid is, however, troublesome and if the removal aid is lost, the filter cannot be replaced.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to provide an insert filter, which can be placed in a shaft of a duct system for guiding gas flow, such that the insert filter can be removed from the shaft without additional removal aids.
This and other objects are achieved in accordance with the present invention by providing an Insert filter for cleaning a gas stream, which is replaceably positioned in a shaft of a duct system through which the gas stream is guided such that the filter separates an unfiltered side from a clean side, the filter comprising a filter frame, a filter element supported by the filter frame, and a shaft cover, wherein the shaft cover is constructed separately from the filter frame and attached thereto, and wherein the filter frame is removable from the shaft exclusively by using the shaft cover.
The insert filter according to the invention is positioned in the shaft of a duct system for guiding a gas stream and serves to purify a gas stream. The duct system can, for example, guide intake air for an internal combustion engine, ventilation air for a clean room, or another gas for a gas consumer. The insert filter is formed by a filter frame, a filter element supported by the filter frame, and a shaft cover connected with the filter frame, with the filter element able to be formed by a filter medium with a border or by a filter medium alone, such as a non-woven fabric or paper.
Furthermore, the filter frame may be comprised of a great variety of materials such as nonwoven webs, thermoplastic, or metal. The insert filter is placed in the shaft in such a way that it separates an unfiltered side from a clean side.
Depending on the filter element with its filter unit, a leakage airflow between the insert filter and the shaft may or may not be permissible. For a coarse filter element, which only filters out coarse impurities, a certain leakage airflow is permissible. For a fine filter element, such as for clean rooms, no leakage airflow is acceptable. In this case, a seal is to be provided between the insert filter and the shaft which, for example, can be positioned on the shaft.
The filter frame, which is completely inside the shaft, is connected with the shaft cover so that the insert filter can be removed from the shaft without an additional removal aid. For this purpose, the side of the filter frame facing the shaft cover can be constructed as taller than the other sides. In this way, a larger connection surface is available for attachment of the shaft cover to the filter frame. The shaft cover is constructed in such a way that it can be easily grasped for replacement of the insert filter. This can be achieved by, for example, a bulge or recesses. The connection existing between the filter frame and the shaft cover is constructed in such a way that the pull necessary for removal of the insert filter from the shaft can be transmitted. The shaft can run partially or completely at a slant in the direction from the top of the shaft to the bottom of the shaft, thereby making introduction of the insert filter into the shaft easier.
The shaft cover can be attached removably or permanently to the filter frame. In this regard, a permanent connection can be produced by, for example, gluing or welding. Removable connections between the shaft cover and filter frame can be formed by positive fits or non-positive fits. For this purpose, screws, hooks, clamps, springs, or fits, for example, can be used. Furthermore, the shaft cover can be inserted in a receiver groove on the filter frame. In other embodiments, the receiver groove can also be positioned on the shaft cover.
The shaft cover can have fastening means available with which the shaft cover is connected with the shaft, so that uncontrolled detachment of the insert filter from the shaft is prevented. Screws, catches, or frets can, for example, serve for this purpose.
According to a further embodiment of the invention, the connection between the filter frame and the shaft cover is constructed so as to be separable. In this way, the shaft cover can be separated from the filter frame after the filter frame is removed from shaft. This is particularly advantageous for replaceable filters in which the filter frame and the filter element must be disposed of, because the shaft cover can be used again. The use of snap hooks to connect the filter frame with the shaft cover represents an advantageous solution, because no additional fastening means are necessary, so that assembly time and expense can be minimized. The shaft cover is snapped onto the filter frame, with the snap hooks springing back and holding the filter frame together with the shaft cover in the assembled state.
It is advantageous to provide an integrated removal aid on the shaft cover, whereby the pull necessary for removal can be better transmitted to the shaft cover. This integrated removal aid can, for example, be formed by an lifting strap, a grip hollow, or a handle. The handle can have one or more attachment points available on the shaft cover, whereby greatly varying embodiments such as a knob or a bow are conceivable.
A further variant of the invention provides a cover seal between the shaft cover and the shaft. This cover seal prevents the entrance of external gases or the escape of gases carried in the duct system and can be connected with the shaft cover or the shaft by, for example, being glued, clipped, or molded on. It is, however, also conceivable that the cover seal is placed loosely between the shaft and the shaft cover and, after the insert filter is completely inserted in the shaft, is pressed between the shaft and shaft cover. Furthermore, however, the cover seal can also be produced through the application of suitable materials such as silicone or adhesive between the shaft cover and the shaft.
A further variant of the invention has a peripheral frame seal on the filter frame which supports itself on the shaft. This frame seal is comprised of a material which has sealing properties, and for this purpose the frame seal can be formed of the same material as the filter frame or of some other material. The frame seal can be inserted loosely in, for example, a groove on the filter frame or, for example, be permanently connected with adhesive or by two-component
Baumann Christoph
Dirnberger Timo
Holtz Steffen
Hoppmann Daniel
Huengsberg Ulrich
Ali Hyder
Crowell & Moring LLP
Filterwerk Mann & Hummel GmbH
Kamen Noah P.
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