WO2018235030A1

WO2018235030A1 - Filtering cartridge with electrically conductive tape

Info

Publication number: WO2018235030A1
Application number: PCT/IB2018/054581
Authority: WO
Inventors: Giorgio Girondi
Original assignee: Ufi Innovation Center S.R.L.
Priority date: 2017-06-23
Filing date: 2018-06-21
Publication date: 2018-12-27
Also published as: EP3641908A1; CN111315465A; IT201700070458A1

Abstract

A filtering cartridge (1) of a fluid filtering assembly housable in a filter body of said filtering assembly. The filtering cartridge (1) comprises a filtering body (2) which extends axially along a main axis (X-X) having a tubular shape. The filtering body (2) comprises an inner filtering cylinder (20), a heating layer (21) and an outer filtering cylinder (22). Said heating layer (21) comprises a first annular device (211) and a second annular device (212), contactable by an external power supply and positioned proximal to the axial ends of the filtering cartridge (1). In addition, said heating layer (21) comprises an electrically conductive tape (210) which extends around the main axis (X-X) extending between the first annular device (211) and the second annular device (212).

Description

DESCRIPTION

"FILTERING CARTRIDGE WITH ELECTRICALLY CONDUCTIVE TAPE"

Field of application

[0001] The present invention relates to a filtering cartridge for a fluid filtering assembly and a method of producing a filtering cartridge.

[0002] The present invention finds specific application in the automotive film. Specifically, in fact, the context in which the present invention falls is that of fluid filtration assemblies whose viscosity is influenceable by the working temperature. For example, preferably, filtering assemblies are known which are adapted to perform the filtration of fuel, preferably of the diesel type, in order to separate the fuel from suspended particles, but also from aqueous particles. Moreover, in the automotive industry, filtering assemblies are known which are adapted to filter blow-by gas, oil, urea or air .

[0003] The main problem in the filtration of fluids is the more or less sudden occurrence of the accumulation of impurities on the first layer of the filtering body crossed by the fluid.

[0004] Obviously, said accumulation of impurities results in a clogging of the filtering body that affects the operation thereof. [0005] This situation is particularly felt when the fluid is at low temperatures (e.g. when the engine is switched on, or in particularly harsh weather situations) and contains a large amount of crystals: for example, paraffin crystals are present in diesel fuel; ice crystals are present in water-based fluids, such as urea; drops, crystals, of condensate are present in aeriform fluids, such as blow-by gas or ambient air.

[0006] In order to overcome this problem, in the prior art, it is known to heat the fuel or, more generally, the working fluid, reducing or avoiding the accumulation of paraffin crystals or, in general, of ice.

[0007] In fact, solutions of filtering assemblies are provided in which the filtering body comprises a heating layer, preferably electrically conductive, the temperature of which is electrically controllable, when necessary, so as to dissolve the crystals and prevent the above clogging.

[0008] The main problem afflicting these filtering cartridge solutions is to bring the power supply to said heating layer.

[0009] Typically, this need involves the design and production of filtering cartridges with particularly complex geometries. For example, filtering cartridges are known which have special electrically conductive cages surrounding the filtering body which on at least one end plate are provided with electrical contacts adapted to be placed in contact with electric supply means.

[0010] The more complicated the geometry of the cartridge and its components, the more complex the respective production operations.

[0011] An example of an embodiment of a filtering assembly exhibiting such a drawback is shown in document EP2811147.

Solution of the invention

[0012] The need to provide a filtering cartridge which has an electrically heatable layer, but above all that has a simple geometry and little complex production is therefore strongly felt.

[0013] Likewise, the need of having a filtering cartridge, comprising a heating layer, producible by means of a simple and effective production method, is therefore strongly felt.

[0014] The object of the present invention is to provide a filtering cartridge and a method of production of said filtering cartridge in which the above need is met and the needs of the specific application field are also effectively and efficiently met.

[0015] Such an object is achieved by the filtering cartridge claimed in claim 1 and by the method of producing a filtering cartridge according to claim 9. The dependent claims describe preferred embodiment variants involving further advantageous aspects.

Description of the drawings

[0016] Further, features and advantages of the invention will be made readily apparent from the following description of preferred embodiment examples thereof, provided purely by way of a non limiting example, with reference to the accompanying figures, in which:

[0017] - figures from la to lg show the various steps of the method of producing a filtering cartridge, object of the present invention, according to a preferred embodiment; in particular, figure lg shows a perspective view of a filtering cartridge according to a preferred embodiment ;

[0018] - figure 2 shows a perspective view of some components of a filtering cartridge as shown in figure lg, in particular it shows an inner filtering cylinder and a heating layer according to a preferred embodiment;

[0019] - figures 3b and 3a show a front view and a longitudinal sectional view, respectively, of the filtering body included in a filtering cartridge according to a preferred embodiment of the present invention;

[0020] - figure 4 shows an enlarged view of a heating tape included in the heating layer, according to a preferred embodiment of the present invention.

Detailed description

[0021] In the accompanying figures, reference numeral 1 denotes a filtering cartridge according to an embodiment of the present invention.

[0022] In particular, said filtering cartridge 1 is specific for a fluid filtering assembly; preferably, the fluid to be filtered is fuel, preferably diesel. In further embodiment variants, the filtering cartridge 1 is specific for a fluid filtering assembly in which said fluid is urea, oil, air, blow-by gas, etc.

[0023] According to the present invention, the filtering cartridge 1 of the present invention is accommodated in a filtering body of the filtering assembly which delimits a dedicated filtering chamber.

[0024] The filtering cartridge 1 extends along a main axis X-X.

[0025] The filtering cartridge 1 comprises a filtering body 2 which extends axially along the main axis X-X having a tubular shape.

[0026] Said filtering body 2, in fact, is traversable by the fluid in the radial direction: from outside inwardly in a preferred embodiment of the present invention such as that shown in the accompanying figures, but also from inside outwardly in an embodiment variant thereof.

[0027] According to the present invention, the filtering body 2, in the radial extension thereof, comprises an inner filtering cylinder 20, a heating layer 21 and an outer filtering cylinder 22. Specifically, in the present disclosure, reference is made to filtering cylinders to indicate filtering means having a substantially cylindrical, tubular shape.

[0028] In other words, the filtering body 2 has three distinct components which develop around axis X-X concentrically to one another. Preferably, the heating layer 21 is thus sandwiched between the inner filtering cylinder 20 and the outer filtering cylinder 22. That is to say, the heating layer 21 is sandwiched between two filter media.

[0029] According to a preferred embodiment, said inner filtering cylinder 20 consists of non-woven fabric of synthetic fibres, or glass fibres, or synthetic fibres mixed with cellulose and/or viscose and/or regenerated viscose fibres.

[0030] According to a preferred embodiment, the inner filtering cylinder 20 has a depth partition consisting of a non-woven fabric of synthetic fibres.

[0031] According to a further preferred embodiment of the present invention, the inner filtering cylinder 20 comprises a plurality of stacked filtering layers. Preferably, such stacked filtering layers exhibit different physical features.

[0032] According to a preferred embodiment, said outer filtering cylinder 22 consists of a non-woven fabric of synthetic fibres, or glass fibres, or synthetic fibres mixed with cellulose and/or viscose and/or regenerated viscose fibres.

[0033] According to a further preferred embodiment of the present invention, the outer filtering cylinder 22 comprises a plurality of stacked filtering layers. Preferably, such stacked filtering layers exhibit different physical features.

[0034] The solution object of the present invention is implementable independently of the thickness of the inner filtering cylinder 20 and the outer filtering cylinder 22.

[0035] According to a preferred embodiment, the heating layer 21 comprises a first annular device 211 and a second annular device 212, electrically conductive and contactable by an external power supply, for example provided on the filtering body (not shown) .

[0036] In addition, the heating layer 21 comprises an electrically conductive tape 210 which extends between the first annular device 211 and the second annular device 212 so as to place them in mutual electrical contact .

[0037] According to a preferred embodiment, the filtering cartridge 1 in the vicinity of the axial ends thereof has said first annular device 211 and said second annular device 212 and the electrical connection between said two components is ensured by the electrically conductive tape 210.

[0038] According to a preferred embodiment, each annular device comprises a contact pin 2115, 2125, which extends in a radial direction to protrude from the filtering body 2 in such a way as to be contactable by an external power supply, for example provided on the filtering body in which the filtering cartridge 1 is housed. Preferably, therefore, each contact pin 2115, 2125 crosses, up to protrude from, the outer filtering cylinder 22 or the inner filtering cylinder 20.

[0039] According to a preferred embodiment, the electrically conductive tape 210 extends in length wrapped around the inner filtering cylinder 20.

[0040] According to a preferred embodiment, the electrically conductive tape 210 extends helical-wise around the main axis X-X.

[0041] Preferably, the electrically conductive tape 210 comprises a plurality of electrically conductive filaments supported by a spacer element, configured as a network or a fabric or a non-woven fabric, adapted to form a series of interstices H between the electrically conductive filaments that make up the conductive tape. The presence of this spacer allows keeping the distance between the conductive filaments wound around axis X-X of the filtering element uniform and facilitates the handling of the tape during the assembly sequence of the filtering element.

[0042] Preferably, the conductive filaments are made of an electrically conductive material such as, for example, stainless steel or aluminium or a metal alloy having an electrical conductivity suitable for the purpose.

[0043] According to a preferred embodiment, the electrically conductive filaments are made of a PTC (Positive Temperature Coefficient) metal alloy. Preferably, said metal alloy is a nickel alloy.

[0044] That is to say, the electrically conductive tape 210 in turn allows being traversed by the fluid, having the electrically conductive portions that vary their temperature on electrical command.

[0045] According to the present invention, the electrically conductive tape is characterized by a width L determined by the value of interstices H and by the diameter of the electrically conductive filaments. The value of H may be less than 5 mm, typically between 1 mm and 4 mm.

[0046] According to an object of the present invention, the electrically conductive tape 210 covers the inner filtering cylinder 20 in a percentage depending on the features of the electrically conductive tape 210 itself, but also depending on the features of the inner filtering cylinder 20 and/or the outer filtering cylinder 210.

[0047] In fact, preferably, the geometrical features of the filaments (number, diameter, length) and the electrical properties of the material used for said filaments (electrical resistivity) determine the thermal power of the system while the value of spacing H determines the percentage of filtering surface covered by said tape and, consequently, the distribution of the thermal power on the filter surface. The distribution type affects the maximum temperature reached on the outer surface of the filtering media and consequently affects the efficiency of the heating system.

[0048] In other words, some portions of the inner filtering cylinder 20 will be in contact with respective portions of the outer filtering cylinder 22. While, where present, the heating tape 210 is arranged between the inner filtering cylinder 20 and the outer filtering cylinder 22.

[0049] According to a preferred embodiment of the present invention, both the first annular device 211 and the second annular device 212 each comprise an inner ring 211', 212' and an outer ring 211", 212", in which the electrically conductive tape 210 is positioned between them.

[0050] Preferably, therefore, an inner ring 211', 212', the electrically conductive tape 210 and an outer ring 211", 212" are located in the radial direction, or vice versa. Preferably, the inner ring 211', 212' lies on the inner cylinder 20, while the outer ring 212" lies on the outer cylinder 22.

[0051] According to a preferred embodiment, the inner ring 211', 212' serves as a support and the outer ring 211", 212" is electrically connectable with the power supply by means of the respective contact pin 2115, 2125. In a preferred embodiment, therefore, the inner ring 211', 212' is not electrically conductive.

[0052] According to a further embodiment, both the inner ring 211', 212' and the outer ring 211", 212" are electrically conductive.

[0053] According to a preferred embodiment of the filtering cartridge 1 object of the present invention, this also comprises a first end plate 31 and a second end plate 32 placed at the ends of the filtering body 2.

[0054] An object of the present invention is also the method of producing a filtering cartridge for a fluid filtering assembly having the features described above.

[0055] Such a production method comprises the steps of:

[0056] - producing an inner tubular element 200 extending along a main axis X-X;

[0057] - wrapping an electrically conductive tape 210 on the inner tubular filtering element 200;

[0058] - arranging a plurality of pairs of annular devices 211, 212, each comprising a first annular device 211 and a second annular device 212, wherein each pair of annular devices 211, 212 is axially spaced from the next along the main axis X-X, wherein each annular device 211, 212 comprises a pin 2125, 2125, which extends radially with respect to the main axis X-X;

[0059] - producing an outer tubular element 220 thus obtaining a tubular filtering body;

[0060] - dissecting said resulting tubular filtering body in the radial direction with respect to the main axis X-X between the first annular device 211 and the second annular device 212, thus obtaining a plurality of filtering bodies 2 similar to those described above.

[0061] According to a preferred embodiment, in said step of the method in which the plurality of pairs of annular devices 211, 212 is arranged with respect to two consecutive pairs, a first axial distance d-d is identified as the distance between two inner annular devices (facing each other), while a second axial distance D-D is identified as the distance between two outer annular devices (i.e. those arranged furthest, respectively) .

[0062] Preferably, therefore, the tubular filtering body is radially sectioned by identifying the ends of the tubular body at an axial section distance A-A; specifically, the tubular filtering body is sectioned radially between the two annular devices belonging to the same pair of annular devices. That is to say, the tubular filtering body is radially sectioned in the space present between the first axial distance d-d and the second axial distance D-D.

[0063] According to a preferred embodiment, the production method comprises the step of:

[0064] - positioning a first end plate 31 and a second end plate 32 on each filtering body, preferably by joining the whole by infrared welding, thus obtaining a complete filtering cartridge 1.

[0065] Preferably, said first end plate 31 and second end plate 32 are placed at the axial ends of each filtering body; namely, between the first end plate 31 and the second end plate 32 is the axial section distance A-A.

[0066] According to a preferred embodiment, in the production method, the step of arranging a plurality of pairs of annular devices 212, 212 comprises, for each annular device, the steps of:

[0067] - arranging an inner ring 211', 212' on the inner tubular filtering element 200;

[0068] - arranging an outer ring 211", 212" at the first inner ring 211', 212'.

[0069] In particular, the wrapping step of the electrically conductive tape 210 on the inner tubular filtering element 200 and on the inner rings 211', 212' arranged thereon is carried out between the above two steps.

[0070] Moreover, according to a preferred embodiment of both the production method and of the filtering cartridge product 1 per se, the electrically conductive tape 210 is wrapped around the inner tubular filtering element 200 helical-wise, with an actual pitch equal to the distance between two pairs of annular devices 211, 212.

[0071] Innovatively, the filtering cartridge and the method of producing a filtering cartridge described above amply meet the object of the present invention overcoming the typical drawbacks of the prior art.

[0072] Advantageously, in fact, the filtering cartridge has a simple and effective geometry. In particular, advantageously, the filtering cartridge has an electrically powered heating layer with a simple power supply mode. [0073] Advantageously, the filtering cartridge has a plurality of radial layers with different physical features to provide different filtering modes. Advantageously, said radial layers are the different cylinders. Advantageously, the same cylinders have specific radial layers therein having different physical features .

[0074] Moreover, advantageously, the heating tape is kept in position due to it being sandwiched between the two filtering cylinders.

[0075] Advantageously, the filtering cartridge contains the heating layer within the filtering body, thus without requiring specific heating components, cages or jackets, surrounding the filtering media.

[0076] Innovatively, the production method provides for simple operations reproducible over time.

[0077] Advantageously, by applying the production method, a plurality of filtering cartridges is obtained at the same time .

[0078] It is clear that a man skilled in the art may make changes to the filtering cartridge or to the production method in order to meet incidental needs, all falling within the scope of protection defined in the following claims .

List of reference numerals: 1 filtering cartridge

X-X main axis

2 filtering body

2 ' central cavity

20 inner filtering cylinder

200 inner tubular filtering element

21 heating layer

210 electrically conductive tape

22 outer filtering cylinder

220 outer tubular filtering element

211 first annular device

211' first inner ring

211" second outer ring

2115 first contact pin

212 second annular device

212' second inner ring

212" second outer ring

2125 second contact pin

31 first end plate

32 second end plate

H interstices of the electrically conductive tape

L width of the electrically conductive tape d-d first axial distance

D-D second axial distance

A-A axial section distance

Claims

1. A filtering cartridge (1) of a fluid filtration assembly housable in a filter body of said filtration assembly, wherein the filtering cartridge (1) extends along a main axis (X-X) and comprises a filtering body (2) which extends axially along the main axis (X-X) having a tubular form being traversable by the fluid in the radial direction, wherein said filtering body (2) in its radial extension comprises:

i) an inner filtering cylinder (20) ;

ii) a heating layer (21) ;

iii) an outer filtering cylinder (22) ;

wherein the heating layer (21) comprises:

- a first annular device (211) and a second annular device (212), both electrically conductive, and positioned proximal to the axial ends of the filtering cartridge (1), wherein each annular device comprises a contact pin (2115, 2125) extending in a radial direction to protrude from the filtering body (2) so as to be contactable by an external electrical power supply, e.g. present on the filter body;

an electrically conductive strip (210) extending in length around the principal axis (X-X) between the first annular device (211) and the second annular device (212) in such a way as to bring them into mutual electrical contact .

2. Filtering cartridge (1) according to claim 1, wherein the electrically conductive strip (210) is wrapped around the inner filtering cylinder (20) .

3. Filtering cartridge (1) according to claim 2, wherein the electrically conductive strip (210) is helically wrapped around the main axis (X-X) .

4. Filtering cartridge (1) according to any one of the preceding claims, wherein the electrically conductive strip (210) comprises a plurality of electrically conductive filaments supported by a spacer element.

5. Filtering cartridge (1) according to any one of the preceding claims, wherein the first annular device (211) and the second annular device (212) each comprise an inner ring (211', 212') and an outer ring (211", 212"), wherein the electrically conductive strip is positioned between them.

6. Filtering cartridge (1) according to claim 5, wherein the inner ring (211', 212') is for support and the outer ring (211", 212") is electrically connectable to the electrical supply by means of the respective contact pin (2115, 2125) .

7. Filtering cartridge (1) according to claim 6, wherein the inner ring (211', 212') and the outer ring (211", 212") are electrically conductive.

8. Filtering cartridge (1) according to any one of the preceding claims, comprising, in addition, a first end plate (31) and a second end plate (32) positioned at the ends of the filtering body (2) .

9. Method for producing a filtering cartridge for a fluid filtration assembly, comprising the steps of:

- producing an inner tubular filtering member (200) that extends along a main axis (X-X) ;

- wrapping an electrically conductive strip (210) on the inner tubular filtering member (200) ;

- arranging a plurality of pairs of annular devices (212, 212), each comprising a first annular device (211) and a second annular device (212), wherein each pair of annular devices (212, 212) is axially spaced from the next one along the main axis (X-X) , wherein each annular device (212, 212) comprises a pin (2125, 2125) extending radially with respect to the main axis (X-X) ;

- producing an external tubular filtering member (220) to obtain a tubular filtering body;

- sectioning the obtained tubular filtering body in a radial direction with respect to the main axis (X-X) between the first annular device (211) and the second annular device (212) thereby achieving a plurality of filtering bodies (2) .

10. Method for producing a filtering cartridge according to claim 9, comprising the step of:

- positioning a first end plate (31) and a second end plate (32) on each filtering body, preferably by combining the whole by means of infrared welding.

11. Method for producing a filtering cartridge according to claims 9 or 10, wherein the step of arranging a plurality of pairs of annular devices (212, 212) comprises for each annular device the steps of:

- arranging an inner ring (211', 212') on the inner tubular filtering member (200) ;

- arranging an outer ring (211", 212") in correspondence with the first inner ring (211', 212') ;

wherein, between the aforementioned steps, the step of wrapping the electrically conductive strip (210) is carried out on the inner tubular filtering member (200) and on the inner rings (211', 212') arranged thereon.

12. Method for producing a filtering cartridge according to any one of claims 9 to 11, wherein the electrically conductive strip (210) is helically wrapped around the inner tubular filtering element (200) with a real pitch equal to the distance between two pairs of annular devices (211, 212) .