Liquid purification or separation – Filter – Within flow line or flow line connected close casing
Reexamination Certificate
2000-02-23
2001-10-30
Savage, Matthew O. (Department: 1723)
Liquid purification or separation
Filter
Within flow line or flow line connected close casing
C210S450000, C210S451000
Reexamination Certificate
active
06308836
ABSTRACT:
The field of the invention is that of the filtration of a liquid, notably oil, fuel or cooling liquid, circulating in an engine, in particular, in a thermal engine or in a piece of hydraulic equipment.
More precisely, the invention relates to a filter of the type comprising a tank that receives a filter cartridge and which can be closed by a closure element, said filter cartridge being detachable and being able to be replaced after a certain using time. This type of cartridge generally has a tubular shape and defines, within the filter, an upstream filtering compartment and a downstream filtering compartment. There are filters in which the upstream filtering compartment is formed between the internal wall of the tank and the outside of the cartridge while the downstream filtering compartment is constituted by the internal chamber of the cartridge while, conversely, in other types of filters, it is the internal chamber of the cartridge that constitutes the upstream filtering compartment, the downstream filtering compartment being formed between the internal wall of the tank and the external wall of the cartridge.
In certain types of engine, the tank of the filter is integrated with the engine block and closed by a cover which can be removed in order to access the filtering cartridge, while in other types of engine, it is the filter tank which is detachable and which can be screwed onto a “filter head” integrated with the engine block. In this description, one therefore understands the term “closure element” as being either the cover mentioned above or the filter head.
When the cartridge positioned in the tank is worn out, that is to say when the filtering element no longer fulfils its filtration role satisfactorily, according to the case, either the cover is removed or the tank is separated from the filter head, the used cartridge is taken out of the tank and is replaced by a new cartridge and the cover is replaced or the tank is replaced against the filter head.
Subsequently, used cartridges are incinerated in such a way that the polluting organic substances are destroyed and the inorganic polluting materials are concentrated. With the aim of optimizing such an operation, it has been proposed in the state of the technology that they are made from “green” materials which can be incinerated given a minimum of polluting materials. Such “green” cartridges have a mono-layered or multi-layered filtering material (also called a “medium” in the language of men skilled in the art) made up, for example, of paper, cardboard, fabric or woven or non-woven fibers (or of a mixture or a superimposition of such materials, one layer of which can be a support layer), most commonly folded into a star, and two end flanges made of a non-metallic material which preferably are not connected to one another by any rigid link other than the medium, which then facilitates their incineration, the lack of any rigid member then allowing one to reduce notably the proportion of plastic material necessary for the manufacture of such cartridges. In the case where a support material is present, this can be rigid or of chosen flexibility.
The operation of this kind of filter is as follows: the liquid to be filtered (for example oil) is admitted through an inlet orifice, it arrives in the upstream filtering compartment, passes through a filtering element of the cartridge which retains the particles found in suspension in the liquid, then the liquid filtered in this way passes into the downstream filtering compartment and leaves through an outlet orifice.
In a conventional way, the sealing of the tank with the closure element is provided by a gasket which must be positioned by the user. So as to facilitate the placement of the cartridge and to avoid handling such a gasket, it has also been proposed in the state of the technology to integrate such a gasket with the periphery of one of the flanges of the cartridge itself, this flange part being blocked between the cover and the tank during placement.
One of the disadvantages associated with the use of this kind of filter is apparent during the operation of clamping the tank with the closure element.
This clamping can, according to the various types of known filters, be carried out notably by directly screwing the tank with the closure element or by bolting it. In the majority of filters, it is very difficult for the user to obtain good clamping, that is to say clamping that is sufficiently strong to enable one to guarantee the seal provided by the gasket provided between the tank and the closure element but not too strong so that the properties of the gasket under consideration deteriorate or that the closure element or the tank is deformed or damaged.
Hence as a general rule, the user has a tendency either to tighten the tank and the closure element too much which leads to a reduction in the sealing capability of the filter and as a consequence its life, or to not tighten it sufficiently which leads to leaks, the gasket then only partially fulfilling its function.
In the filters that use several bolts to fix the closure element onto the tank, the clamping obtained is generally not well distributed between the various bolts, which increases the risks of leaks or of deterioration of the gasket. This problem is increased because this clamping operation must be carried out using a tool which makes it even more difficult to judge the degree of clamping.
In order to respond to this problem, it has already been proposed in the state of the technology to provide a gasket between the closure element and the tank. Such a solution has however the disadvantage of using a gasket which is not integral with the filter cartridge and also that of implying a contact between the metal of the closure element and the metal of the tank, such a contact possibly leading to seizing. Finally, such a solution necessitates a high clamping torque.
The objective of this invention is to describe a technical solution that allows one to use a seal integrated with a second flange of the filter cartridge and enables one to provide a homogeneous and straightforward clamping of the closure element with the tank, using a moderate tightening torque that can be provided manually.
This objective is achieved by the invention which relates to a filter for a liquid circulating in an engine block or in a piece of hydraulic equipment that includes a tank co-operating with a closure element and a filter cartridge inserted into said tank and locked into it by clamping said closure element with said tank, said cartridge being of the type that includes a filtering material having at one of its ends a first flange and at the other of its ends a second flange the peripheral part of which is designed to be blocked between said tank and said closure element when said tank is clamped with said closure element,
characterized in that it includes at least one element forming a stop provided on said second flange and/or said closure element and/or on said tank, said element forming a stop being designed to control said clamping of said tank with said closure element.
Such a stopping element allows the user to know at what moment the ideal clamping of the closure element with the tank has been achieved. It should be noted that such clamping will generally be carried out by screwing, this screwing taking place according to case, by screwing the closure element (cover) onto the tank, when this is integral with the filter head or by screwing the tank onto the filter head which then constitutes the closure element. In the first case, the invention could also be implemented when the cover is bolted onto the tank.
Furthermore, such a stopping element allows one to use a moderate tightening torque that permits effective clamping by hand and produces a clear sensation of clamping. This stopping element therefore enables one to avoid all the problems associated with too tight a clamping or insufficient clamping that are mentioned above.
It could also be envisaged to create the stopping element according to the invention on one of th
Guichaoua Jean-Luc
LeRoux Benoit
Picard Jean-Yves
Fleetguard Inc.
Gron Gary M.
Savage Matthew O.
LandOfFree
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