A FILTER FOR FILTERING ENGINE OIL

This invention relates to a filter for filtering engine oil.

Filters for filtering engine oil are used in equipment such for example as vehicle engines and manufacturing plant. Often the equipment is used in temperature conditions which are hot during the day and substantially colder at night. Such a drop in temperature at night can lead to condensation of water from the atmosphere and this water can be taken up by the oil. Engines that are run with water in the oil may become damaged.

Engines are also damaged when they run with oil that contains metallic particles. The metallic particles come from parts of the engine itself and are usually caused during manufacture and/or running of the engine.

New and unused engine oil generally does not contain mutagens. As the oil is used in an engine, the period of use of the oil, the pressure at which the oil is used, and the temperature at which the oil is used, may cause the creation of mutagens. Many of these mutagens are toxic and they can cause fatal diseases such for example as cancer. It is customary to change engine oil at recommended intervals, for example at 6,000 mile intervals. I have now established that the recommended oil change intervals are sufficiently long that toxic levels of mutagens will be present in the engine oil. Indeed, the toxic levels of the mutagens will be present long before the recommended oil changes. The problems of harmful levels of mutagens in used engine oil is being exacerbated because engine

manufacturers are constantly striving towards producing engines that require oil changes at longer intervals rather than shorter intervals. Still further, the mutagens in the used engine oil make it dangerous to try and recycle the engine oil by treating it so that it can be re-used.

It is an aim of the present invention to provide a filter which is able to reduce the above mentioned problems.

Accordingly, in one non-limiting embodiment of the present invention there is provided a filter for filtering engine oil, which filter comprises a body, an inlet for engine oil passing into the body, an outlet for the engine oil passing out of the body, a foam material in the body for filtering the engine oil and removing water in the engine oil, magnet means in the body for attracting and retaining particles of magnetically-attracted material in the engine oil, and activated carbon in the body for removing mutagens from the engine oil.

The filter of the present invention is advantageous in that the foam material absorbs the water in the liquid. If the oil also contains silt, then this silt may also be removed by the foam material. The foam material is advantageous in that it contains a large volume of air and thus has a large operative surface area. The foam material may be regarded as having a honeycomb structure. The foam material may be 98% by volume air. The structure of the foam material thus gives very effective filtration and water absorbing.

The filter of the present invention is also advantageous in that the magnet means is able to remove magnetically-attracted material such for

example as metal particles that could otherwise damage the engine. The magnet means may be a disc. The disc may be provided with a plurality of holes. The magnet means should be of a size and/or constructions that does not cause undue resistance to the flow of the engine oil through the filter.

Preferably, the filter is one in which the activated carbon is fine particle activated carbon. Such fine particle activated carbon provides a large active surface area for filtering the mutagens.

Preferably, the activated carbon is 44 micron activated carbon. The activated carbon may be smaller or larger is size than 44 micron. Generally, increasing the micron size of the activated carbon reduces the active surface area. Reducing the size of the activated carbon may make the activated carbon of such a small particulate size that special handling is required. Preferably, the activated carbon is dust free activated carbon. A presently preferred dust free activated carbon is that produced by Chemviron Carbon of Sheffield, United Kingdom under Type No. SGL 8X30, Reference FE 05830A.

The filter may include retainer means for retaining the activated carbon in place.

The retainer means may be made of a foam material. The foam material may be a woven foam material and/or a polymer foam material. The foam material may be the same as the foam material that absorbs the water in the engine oil.

The filter of the present invention is further 'advantageous in that the active carbon is able to filter the mutagens from the engine oil. More specifically, the mutagens can be filtered from the engine oil as they are created. The filtered mutagens can be retained in the filter where they will cause minimum health problems. The activated carbon is a substance having large molecules and these large molecules are able to trap the mutagens. In addition, the activated carbon is a relatively cheap material, and one that is able to be achieved from natural sources. Thus the activated carbon itself is inexpensive to use so that it is able to meet commercial considerations, and the carbon is safe to use so that it is able to meet health and safety considerations. Thus the filter of the present invention is able to solve a considerable health problem in a cheap and failsafe manner. After use, the filter with the mutagens can be destroyed, for example by burning or any other suitable and appropriate method.

The filter of the present invention may be used with substantially all engines such for example as petrol engines, liquid petroleum gas (LPG) engines and diesel engines. The engines may form part of moving vehicles such for example as road vehicles in the form of cars, lorries, buses and motor cycles. Alternatively the engines may be in the form of tractors or earth moving equipment. The engines may also be in static equipment such for example as electrical generators and pumps.

The filter may be produced to be smaller than known filters of comparable filtering capacity. Thus, the filter of the present invention may be of especial use in engines where space is a problem.

The foam material is preferably a woven foam material.

The foam material may be a polymer material.

The foam material may be a foam material which is not hygroscopic. A presently preferred such material is that manufactured by the Camelot Company. Because the foam material is not hygroscopic, it does not become wet in humid atmospheres and so there is no need to protect the foam material, for example by encapsulating it, from the effects of the atmosphere. An alternative less preferred foam material which can be used and which is in fact hygroscopic is that sold under the trade mark Luquafleece by BASF Superabsorbents Ltd. of Birkenhead, United Kingdom.

The foam material may be in pieces which are positioned in the body.

Alternatively, the foam material and/or the activated carbon may form part of a cartridge which is positioned in the body. Advantageously, the cartridge may be a disposable cartridge so that the body of the filter can continue to be used with different cartridges. Used cartridges can simply being replaced by new cartridges. With such an arrangement, a pack could be sold with the filter comprising the body, the inlet and the outlet, and a plurality of the disposable cartridges for use with the same body. If desired however, the cartridge could be a permanent cartridge.

The cartridge, for example the disposable cartridge, may include a support member for the foam material and/or the activated carbon. The support member may have a plurality of apertures along its length for enabling the engine oil to pass through the support member.

In one embodiment of the invention, the foam material is positioned around the outside of the support member. In this embodiment of the invention, the foam material is preferably in sheet form and it is wrapped around the outside of the support member.

In an alternative embodiment of the invention, the foam material is positioned inside the support member. In this case, the foam material may be in sheet form or in the form of pieces. The filter may include end screen members for retaining the foam material and/or the activated carbon in the support member.

The filter may include a non-return valve. The non-return valve may be positioned in an end part of the filter.

The filter of the present invention may be of any suitable and appropriate construction. The body of the filter may be made of a plastics material. Any suitable and appropriate plastics materials may be employed. The plastics materials may be transparent for see-through purposes, or non- transparent. The body of the filter may also be made of a metal.

The filter may be one having a separate inlet and outlet.The separate inlet and outlet are preferably formed for push on hose connections held in place by clips such as jubilee clips. Other formations may be employed so that, for example, the separate inlet and outlet may be for receiving screw fittings or snap fittings. The filter may alternatively have a single combined inlet and outlet, and such a filter may be one in which the combined inlet and outlet is an internally threaded aperture for enabling the filter to be a screw threaded connection to a circuit, for example a hydraulic circuit.

It may be advantageous to know when the filter is blocking or a system containing the filter is blocking. Pressure sensing means such for example as a pressure differential gauge can be built in, so that a user can constantly monitor system conditions. The monitoring may be effected locally, or even remotely, for example for hospital emergency standby generators.

The use of the foam material, the magnet means and the activated carbon may also be advantageous in that they need not dictate the shape of the filter or component parts of the filter. Thus the filter can be made in a wide variety of shapes. This can be advantageous in causing the filter to be made in a shape, for example a star shape, that gives an oil cooling function. With such a shape, the filter can act as an oil cooler. With sufficient oil cooling from the filter, hitherto used radiators could be reduced in size or even dispensed with.

Embodiments of the invention will now be described solely by way of example and with reference to the accompanying drawings in which:

Figure 1 is a cross section through a first filter for filtering engine oil;

Figure 2 is a perspective view of the filter shown in Figure 1 ;

Figure 3 is an exploded view of a second filter for filtering engine oil;

Figure 4 is a an exploded view of a third filter for filtering engine oil;

Figure 5 is a perspective view of a part of the third filter for filtering engine oil shown in Figure 4;

Figure 6 shows two charts relating to the testing of liquid petroleum gas and petrol for mutagens after predetermined use periods;

Figure 7 shows a first chart illustrating the advantages of the invention; and

Figure 8 shows a second chart illustrating advantages of the invention.

Referring to Figure 1, there is shown a filter 2 for filtering engine oil. The filter 2 comprises a body 4, an inlet 6 for engine oil passing into the body 4, an outlet 8 for engine oil passing out of the body 4, and foam material 10 in the body 4 for filtering the engine oil as it passes through the body 4. The foam material 10 acts to absorb water and silt in the engine oil.

The foam material 10 is a woven polymer foam material. The woven polymer foam material is non-hygroscopic. The foam material 10 is in small pieces as shown.

The filter 2 also comprises activated carbon 11 for removing the mutagens that are in the engine oil and that are created during use of the engine oil in the engine. The activated carbon 11 is in the form of a separate layer in the filter 2.

The filter 2 further comprises magnet means which is in the form of a disc magnet 15 and which is for removing magnetically-attracted material, for example ferrous material, from the engine oil. The disc magnet 15 has apertures 17 for ensuring that the disc magnet 15 does not unduly block the flow of the engine oil through the filter 2.

The body 4 is made of a plastics material. The body 4 comprises a main body part 16 and a cap part 18 which screws to the main body part 16 via screw threads 20. The cap part 18 may have a grip portion 22 for

helping the cap part 18 to be tightened and un-tightened from the main body part 16.

An oil seal 24 is provided for preventing loss of the engine oil from between the main body part 16 and the cap part 18 when the filter 2 is operating under hydraulic pressure.

The main body part 16 and the cap part 18 may be made as mouldings, for example from glass reinforced nylon.

The filter 2 may includes a non-return valve (not shown). The nonreturn valve acts as an anti-drain valve.

A screen 26 are positioned as shown in order to retain the pieces of the foam material 10 in the body 4

Reference will now be to the following Example in which new oil with various additives was twice filtered through a filter 2 of the construction shown in Figure 1. A control batch of the engine oil was passed through a known filter. Another portion of the engine oil was passed through the filter 2 shown in Figure 1. The results obtained are given hereinbelow. These results deal solely with the effect of the foam material.

TABLE 1

OIL PASSED THROUGH KNOWN OIL FILTER WITH NO FOAM MATERIAL

Additives New Oil Filtered Once Filtered Twice

Iron 5 4 4

Chromium 0 0 0

Aluminium 0 0 1

Copper 1 1 1

Lead 4 5 4

Nickel 0 0 0

Tin 0 0 0

Manganese 0 0 0

Titanium 0 0 0

Silver 0 0 0

Molybdenum 0 0 0

Zinc 405 403 319

Phosphorus 270 269 263

Calcium 38 35 35

Barium 0 0 0

Magnesium 1 1 1

Silicon 1 2 1

Sodium 3 6 6

Boron 1 1 1

Vanadium 0 0 0

Water 163ppm 123ppm 209ppm

OIL PASSED THROUGH FILTER WITH FOAM MATERIAL

(Figures 1 and 2).

Additives New Oil Filtered Once Filtered Twice

Iron 0 0 0

Chromium 0 0 0

Aluminium 0 0 0

Copper 0 0 0

Lead 0 2 1

Nickel 0 0 0

Tin 0 0 0

Manganese 0 0 0

Titanium 0 0 0

Silver 0 0 0

Molybdenum 0 0 0

Zinc 426 441 547

Phosphorus 269 266 281

Calcium 26 27 28

Barium 0 0 0

Magnesium 0 1 1

Silicon 4 5 4

Sodium 0 0 0

Boron 0 0 0

Vanadium 0 0 0

Water 84ppm 91ppm 84ppm

It will be noted from Table 1 that the additives of zinc, phosphorus and calcium are at an acceptable level, both in the new engine oil and after the engine oil had been filtered twice. However, the amount of water in the new engine oil was 163ppm but this increased to 209ppm at the second filtering. This amount of water in the engine oil was not acceptable.

It will be noted from Table 2 that the additives of zinc, phosphorus and calcium remained at acceptable levels and also that the water remained at an acceptable level. More specifically, the water content of the engine oil after the second pass through the filter 2 was exactly the same as the water content of the new oil, namely 84ppm. Thus the filter 2 with the foam material 10 maintained the water content of the engine oil after two passes through the filter 2 at exactly the same level of parts per million as it was initially in the new engine oil. Further, the use of the foam material 10 did not adversely affect the additives in the engine oil and thus the additives were able to perform the function which they were intended to by the oil manufacturer. Also, the use of the foam material 10 absorbed silt in the engine oil, this not being shown in Table 2. The foam material 10 acts as a purifier to purify the engine oil from the water and the silt.

Referring now to Figure 6, there are shown two charts, one for liquid petroleum gas and the other for petrol. The two charts show the effect of the activated charcoal on mutagenicity of the engine oil.

Petrol engine oil is shown to be mutagenic in the presence and absence of liver S9 metabolic activation. The effect was tested of activated charcoal on the mutagencity of a petrol engine oil sample without the liver

S9. Charcoal was mixed with the oil and DMSO (equal volumes) and after sedimenting the charcoal, 100 microlitres of supernatant were tested. The results are given below.

Number of revertants (mutagenicity) S a m p l e S. typh. TA98

Negative control 20, 23, 30

Oil - charcoal treatment 113, 100, 105

Oil + charcoal treatment 23, 26, 24

Figure 10 illustrates the testing of two engine oil samples for mutagenicity in Salmonella typhimurium strain TA98 as DMSO/oil emulsions. Tests were in triplicate with a range of concentrations.

1. LPG with polymer, c.a. 4000 miles

2. Petrol with polymer, c.a. 2000 miles

Both samples gave a dose - response both with and without a metabolic activation system.

This indicates that both samples contained mutagens. The values were higher when a metabolic activation system was present.

Figure 7 shows a chart for a with-charcoal treatment and a without- charcoal treatment. The advantages of the use of the activated charcoal can clearly be seen.

Figure 8 shows that in all instances levels of mutagenicity are able to be reduced by the present invention. Figure 8 gives percentage levels of reduction of mutagens for the specified test conditions.

The filter 2 is also advantageous in that it uses snap-on fittings for the inlet 6 and the outlet 8. The snap-on fittings are cheaper than screw threads to manufacture, they require simpler tooling, and they are easier to use than threaded fittings. With threaded fittings, there is a tendency for people fitting the filters to over-tighten the threads and/or to cross thread the threads.

The filter 2 is also advantageous in that the screens 26 can easily be located adjacent the inlet 6 and the outlet 8 by welding. The welding may be ultrasonic welding, for example where the body 4 and the illustrated lid 4 are made of plastics materials.

If desired, the oil filter 2 can be made such that the body 4 and/or the lid 4 are made of a transparent plastics material so that it is possible to see inside the oil filter 2 and see how the foam material 10 is working.

The oil filter 2 may be manufactured as a cheap, easily installed and highly efficient disposable filter. By removing water from the engine oil, damage to equipment can be avoided, which in turn helps to reduce warranty claims for equipment manufacturers.

Referring now to Figure 3 there is shown a filter 28 comprising a body 30, an inlet for liquid passing into the body 30, and outlet for liquid passing out of the body 30, a foam material 32 for filtering the liquid as it passes through the body 30 and also for absorbing water in the liquid, the disc magnet 17 shown in Figures 1 and 2, and the activated carbon 11. The filter 28 shown in Figure 3 is advantageously employed as a filter for an engine for a road vehicle such for example as a car.

The foam material 30 is a woven polymer foam material. The foam material 30 is in sheet form which is wound around a support member 34. The support member 34 with the foam material 30 forms a disposable cartridge which can be replaced in the body 30 when it becomes used up. The positioning of the disc magnet 17 and the activated carbon is reversed to that shown in Figures 1 and 2.

The support member 30 has top and bottom flanges 36, 38 respectively for helping to locate the wound foam material 32, and also for ensuring that the foam material 32 does not slip longitudinally on the support member 34.

The support member 34 has a plurality of apertures 40 along its longitudinal length. These apertures enable the filtered liquid, for example filtered oil, to pass through the wall of the support member 34 and be filtered by the foam material 32. The flow and return can be of any suitable and appropriate way so that the material being filtered could flow radially outwardly or radially inwardly with respect to the support member 34.

Also shown in Figure 3 is a bottom part 42 of the filter 28. The bottom part 32 has an internally screw-threaded portion 44 which screws to an externally screw-threaded portion 46 of the body 30. Engine oil flow through the filter 28 is shown by arrow 48, and engine oil return through the oil filter 28 is shown by arrow 50. The engine oil flow shown by arrow 48 is such that the engine oil passes through apertures 52 in the bottom part 42. These apertures 42 are advantageously covered with a diaphragm (not shown). Thus, when the engine is not operating, the diaphragm retains

engine oil in the filter 28 because it prevents the engine oil from running out through the apertures 52. Thus, at start-up conditions, the filter 28 is always full of engine oil and there is no period when the engine could be starved of engine oil for lubrication purposes.

Figure 3 shows schematically part of the engine 54. The engine 54 is provided with a threaded stud 56 onto which the oil filter 28 is screwed.

Figure 4 shows a third filter 58 which is for filtering engine oil and which also employs a replaceable cartridge similar to that shown in Figure 3. Similar parts have been given the same reference numerals for ease of comparison and understanding.

In Figure 4, there is shown a top part 60 which has a threaded portion 62 for enabling the top part 60 to be screwed into position on the top of the body 30 of the filter 58.

Figure 5 is a perspective view of the top part 60 and it will be seen that the top part 60 has a boss 64 for receiving a pressure relief valve (not shown). The pressure relief valve is employed for ensuring that, in the event of a blockage, the pressure relief valve will enable engine oil still to be passed to the engine.

It is to be appreciated that the embodiments of the invention described above with reference to the accompanying drawings have been given by way of example only and that modifications may be effected. Thus, for example, the bodies of the oil filters are preferably made of a plastics material so that the oil filters can be recycled. The engine oil filters can however be made of other materials such as metals if desired. The oil filters

may be such that it is secured in position by means other than screw threads. The filters can be mounted in any suitable and appropriate position.

Where a pressure relief valve is employed, then the pressure relief valve may comprise a ball valve and a spring for biasing the ball valve to a normally closed position against a valve seat. If the filter should become blocked with filtered impurities from the oil, then the engine oil may not be able to get through the filter. Any engine requiring the oil could thus be starved of the oil. If the oil filter becomes blocked, then pressure will rise in the filter. This will cause the engine oil to flow through apertures and force the ball valve off its seat. A bore will then be opened and the engine oil can flow along the passageway to the outlet. Thus, the engine oil will still be provided to an engine or whatever else requires the oil, even in the event of a blockage in the filter.

The pressure relief valve is advantageously located as shown in a cap part of the filter. Thus the cap part can be removed from the main body part in order to allow the foam material, for example in the form of a cartridge to be replaced. The use of replacement cartridges can thus be effected without having to throw away the main body or the cap part of the filter. These parts are relatively expensive, especially when they contain the pressure relief valve. Thus the filter of the present invention can be extremely cheap to maintain.

The magnet means, for example the disc magnet 15, may be located in the cap or lid of the filter. Thus the magnet can easily be retained if the

filter is opened up and provided with new water absorbing polymer material and new activated carbon. The cap or lid may be a bayonet fitting to the main body instead of being a screw threaded fit.

In Figures 1 and 2, the inlet 6 and the outlet 8 may be reversed. If desired, the oil filter 2 may be rotated through 90° from the position shown in Figure 1 so that the filter 2 may be installed horizontally rather than vertically as shown in Figure 1. If desired, the inlet and the outlet may both be in a single opening in the filter.