Liquid purification or separation – With repair or assembling means
Reexamination Certificate
2001-12-14
2004-02-03
Lithgow, Thomas M. (Department: 1724)
Liquid purification or separation
With repair or assembling means
C210S248000, C210S130000, C210S131000, C210S440000, C210S444000
Reexamination Certificate
active
06685829
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a fluid filter suitable for use in an internal combustion engine.
This type of filter is known from DE-C2-34,09,219.
DE-U1-296,10,290 discloses a filter with a spring-loaded discharge valve fixed to the housing, which valve is retained in its closed position by the filter insert and which is opened when the filter is opened or the filter insert removed.
DE-U1-04,11,212 discloses a filter in which the discharge opening is closed by a screw.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a generic filter that is as cost-effective and as space-saving as possible.
This object is achieved by a filter having a discharge dome that is fixed to the filter housing.
The invention proposes, in other words, a filter in which the discharge dome is designed not as a component which is part of the removable filter insert but as a component which is fixed to the housing such that the discharge dome always remains on the filter. This approach allows for the space-saving packaging of the actual filter inserts since the top-to-bottom height of the latter is reduced by that dimension which is provided in generic filters as the closure pin which is still connected axially to the actual filter medium. The separate discharge domes themselves have a diameter which is considerably reduced with respect to the filter inserts and may thus be packaged in a considerably more space-saving manner for delivery to the engine manufacturer: either separately from the filter inserts, or if necessary located in the inner chamber of the filter insert, thereby obviating the need for a second, separate package—thereby enabling a shipping process which is overall more space-efficient and material-efficient, and generally more cost-efficient.
This cost advantage is particularly relevant to the supply of replacement parts, first of all again due to the space-and cost-efficient shipping of the filter inserts, and secondly as the material portion of the discharge dome is completely obviated since this component remains fixed to the filter housing—with the result that the cost of replacement parts is reduced twofold.
In the filters according to the species, the discharge line is opened by removing the filter insert since the discharge dome is removed from the filter housing together with the filter insert. In the present invention, exactly the same motion of filter insert and discharge dome is effected in that the spring-loaded discharge dome returns to its release position when the spring is released. This spring is compressed when the filter insert is inserted into the-filter housing, and the cover of the filter housing is closed, the discharge dome being moved into its closed position at the same time.
An additional cost savings during manufacture of a filter according to the invention results from the fact that the discharge dome advantageously is not only designed to function as the discharge closure device but is provided with a second valve function. The latter may, for example, form the conventional filter bypass valve which enables the fluid to bypass the filter medium in the event of excess pressure, or it may constitute an anti-drainback valve which prevents the oil from draining back into the crankcase and thus emptying the filter housing.
Specifically, there may be the simple and component-saving provision of having this additional valve function controlled by the axial adjustability of the discharge dome. In this way, the discharge dome may be fabricated from very few components and the valve functions integral to it realized in a particularly cost-effective manner; and the user, for example in the automobile plant, may save assembly steps of mounting various valves required for the associated valve functions.
An especially cost-effective provision may be made in which the additional valves are not yet functional at the delivery stage of the discharge dome but constitute simply a valve body which forms a functioning valve only when interacting with an additional sealing surface independent of the discharge dome. This approach permits the assembly of the valve body to be effected in an especially simple and cost-effective, i.e. optimally accessible manner.
A support dome within the filter insert may be advantageously provided in the conventional manner such that the removable filter insert may be fabricated using very little material, and its filter medium may attach to the permanently installed support dome remaining in the filter. This support dome may be advantageously designed as an extension or axial continuation of the discharge dome so that as few components as possible need to be fabricated and manipulated, with the resulting positive effect on manufacturing and assembly costs. Specifically, the extension of the discharge dome thus created permits a filter bypass valve to be provided on the side of the valve insert located opposite the discharge opening.
When designing the support dome as an extension of the discharge dome, it may be advantageous in certain cases to design the dome to consist of two sections such that when manufacturing a “product family” of filters, only one uniform base part having the discharge dome is fabricated and parts of various length dependent on the differing top-to-bottom heights of the filter housing and filter inserts are always connected to the same base component so as to ensure the sufficient support function of the dome.
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Ardes Wilhelm
Baumann Dieter
Ing. Walter Hengst GmbH & Co. KG
Lahive & Cockfield LLP
Lithgow Thomas M.
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