Patent Application
20170368484
The present invention pertains to a method and apparatus for removing water from oil. The present invention furthermore pertains to a method and apparatus for removing water from oil in combination with a tubular filter for filtering solid particles from said oil and a method of manufacturing said filter and a method of filtering oil.
The technical industries have problems with water contaminations in oils for lubrication, different power transmissions or transformers (hydraulics, gears, valves, etc.), wherein even small quantities of water severely impair the properties of said oils. Such contaminated lubricating oil used in internal combustion engines and other equipment is a principal cause of excessive wear and deterioration of engine parts and related equipment. At present, most internal combustion engines employ only a conventional mechanical filter for extracting materials such as dirt, carbon, soot, metal particles and other similar foreign material from lubricating oil. Liquid contaminants such as condensates, water and fuel, are often emulsified in the lubricating oil and cannot be separated by a conventional filter. It is therefore necessary for the lubricating oil of internal combustion engines using such mechanical filters to be changed at frequent intervals in order to minimize engine damage by contaminants entrained therein.
In recent years, the increasing worldwide price of oil has made it imperative to develop ways of reconditioning oil, e.g. lubricating oil, so that it may be used and reused for a longer time than hitherto. In this way, only small amounts of additional lubricating oil are required by engine usage.
The problem of liquid contaminants has been recognized, and some efforts have been made to develop devices, which use heat as a mechanism for separating oil and contaminants. Exemplary previous devices of this type are disclosed in U.S. Pat. No. 2,635,759, U.S. Pat. No. 2,785,109, U.S. Pat. No. 2,839,196, U.S. Pat. No. 3,550,871, U.S. Pat. No. 3,616,885, U.S. Pat. No. 3,915,860, U.S. Pat. No. 4,006,084, U.S. Pat. No. 4,146,475 U.S. Pat. No. 4,349,438.
These filters are, however not very efficient in removing water from oil. Therefore, these conventional oil filters, largely, are only slightly superior to the prior disposable filters, which remove only solid contaminants. With this oil filtering devices the engine lubricating oil may only be used for a slightly longer time than with conventional solid contaminant removing filters. The marginal improvement in oil recycling life that results from removing a small amount of the liquid contaminants cannot justify the incremental cost required to achieve this improvement.
In addition to the above-mentioned kind of filtering devices, it has for example been suggested in WO 86/04830 and WO 2007/015644 to use atomizing nozzles in order to enhance the separation of water from lubricating oil. However, there has been a need in the marked for more efficient filters for removal of water, from oil, and for efficient filters, which are able to effectively remove both water and solid particle contaminants in oil.
Traditionally, existing fluid filters that are adapted for filtering particles from fluids, are surface filters in the sense that the filtering occurs at just the outer surface of the element where the fluid first enters the element. With very fine surface filter elements, particles tend to accumulate at the outer surface, thereby loading the filter element and cutting off the flow of fluid through it. As a result, filtering is degraded and the element must be changed more frequently than desired. This has been a particular problem with high viscosity fluids such as oil, engine oil in particular. In order to alleviate this surface build-up problem so called string/yarn wound filters wherein a yarn is wound on a tubular bobbin have been developed. These filters have the advantage, that the fluid is filtered all the way along the thickness of the wound yarn. Examples of such yarn wound filters are known from EP 0489157, U.S. Pat. No. 5,552,065, U.S. Pat. No. 4,761,231, U.S. Pat. No. 5,772,952, FR 2097502 and WO 2007/015643.
This filter alleviates some of the problems associated with the other types of filters mentioned above and known in the art. However, it has been observed that some of the water that evaporates from the oil tend to condensate on the inner surface of the ventilation chamber, and thereby flow back together with the oil. Furthermore, it has proven to be technically complicated in praxis to provide adequate (i.e. enough, but not too much) heating of the distillation head, especially when the filter is used to filter water from a highly flammable type of oil, such as diesel.
It is thus an object of the invention to provide an improved, and less complicated, method and apparatus for removing water from oil.
It is a further object of the invention to provide an improved, and less complicated, method and apparatus for removing both water and solid particle contaminants in oil.
According to the present invention, the above-mentioned and other objects are fulfilled by a first aspect of the invention pertaining to a filter for the removal of water from oil, the filter comprising a distillation element having an inlet pipe that in one end is to be fluidly connectable to a reservoir of oil to be filtered, and in the other end being fluidly connected to a distillation head, said distillation head comprising a plurality of compression tubes for compressing said oil into an evaporation chamber, whereby eventual water within the oil evaporates from the said oil, the filter further comprising a tubular core with a plurality of apertures and a hollow interior, said core having an open end for fluid communication with the hollow interior, a length of yarn wound around an outer surface of the core, wherein the filter further comprises means for blowing air or an inert gas into the evaporation chamber for removal of the water vapor during use of the filter.
By providing a plurality of compression tubes for injecting the oil into the evaporation chamber, the oil is compressed as a liquid into the evaporation chamber. Due to the different thermodynamic properties of the oil and the water, they react differently to changes in heat and pressure. These vaporized contaminants; (steam) is then blown out of the evaporation chamber by the air or inert gas, which is blown into the evaporation chamber, while the oil is drained out in liquid form. A plurality of compression tubes is used in order to ensure an adequate flow rate, and the actual number of compression tubes needed may be chosen in dependence of the particular application of the inventive filter and oil types.
The technical industries have particular difficulties with water contaminants in oils used for lubrication and different transmissions or transformers (hydraulics, gears, valves etc.). These contaminants arise from condensation, leaks, frost, etc. Non combusted fuel remnants, acids and eventually other alien liquids can also be present. Acids and bacterial growth may be formed in the presence of water. Thus, by removing water, a lot of related problems are solved. Furthermore, since the filter additionally employs a length of yarn that is wound around a tubular core, effective removal of slid particles is achieved as well as removal of water in one single operation. An inert gas instead of air is preferably used in case the oil to be filtered is highly flammable type of oil, such as diesel.
In a preferred embodiment of the filter according to the invention, said means for blowing air or an inert gas into the evaporation chamber is for example a fan that is in fluid communication with said evaporation chamber via a pipe.
In a further preferred embodiment of the filter according to the invention, the evaporation chamber comprises an outlet for the air or inert gas, which during use is blown into the evaporation chamber.
Preferably, the compression tubes are made from a metal or metal alloy comprising aluminum, which has good heat conductivity and low reactivity with oil.
In an embodiment the compression tubes have barrel sizes that are smaller than 7 mm, preferably smaller than 3 mm or between 0.5 mm and 7 mm, preferably between 0.5 mm and 3 mm, more preferably between 0.7 and 1.2 mm. Separation is achieved by selecting a barrel size that creates a significant pressure differential across the opening. The viscosity of different oils is largely dependent of temperature, so the barrel sizes are preferably chosen in dependence of the temperature increase the oil undergoes during friction with the barrels, and the type of oil to be filtered. To this end the applicant estimates that by using barrel sizes as mentioned above it would be possible to separate water from most types of oils.
However, there is a delicate balance in selecting proper barrel opening sizes, because the opening size controls both the extent of separation and the flow rate through the filter. Selection of the barrel opening also controls the pressure differential between the oil inlet and the evaporation chamber.
The compression tube have preferably a barrel that is rifled in order to thereby impart a rotational motion to the compressed injected oil and thereby enhance the separation (evaporation) of contaminants from them.
In a preferred embodiment the length of the barrel of each of the compression tubes is between 4 mm and 40 mm.
In a preferred embodiment the evaporation chamber has a sloped floor with an oil drain that during use is configured to be situated at the lowest place of the floor. Hereby is achieved that the oil—relieved form most of the water contaminants—may be drained from the bottom of the evaporation chamber, while the gaseous phase, water steam, is removed from an upper part of the evaporation chamber by blowing in an inert gas or air. Here the terms “lower” and “upper” refers to the lower and upper parts of the ventilation chamber, when the filter is installed in its correct use position.
Advantageously, the oil is pressurized, e.g. to a pressure of between 8 bars and 40 bars, before it injected through the compressing tubes.
In a preferred embodiment, the evaporation chamber has a sloped floor with an oil drain that during use is configured to be situated at the lowest place of the floor. Hereby is achieved that the oil—relieved form most of the water contaminants—may be drained from the bottom of the evaporation chamber, while the gaseous phase, water steam, is removed from an upper part of the evaporation chamber by blowing in an inert gas or air. Here the terms “lower” and “upper” refers to the lower and upper parts of the ventilation chamber, when the filter is installed in its correct use position.
Advantageously, the oil is pressurized, e.g. to a pressure of between 10 bar and 20 bar, before it atomized through the nozzles.
In a preferred embodiment of the filter, the yarn is wound in a series of at least 4 layers around the outer surface of the core, wherein the first layer closest to the surface of the core comprises at least 15 windings of the yarn, the second layer comprises at least 15 windings of the yarn and the third layer comprises at least 10 windings of the yarn, and wherein at least two consecutive layers have been wound in accordance with different winding patterns.
Investigations performed by the applicant has shown that this particular way of building up the filter in a layered structure of yarn that wound onto the tubular core in accordance with winding patterns that are different for three consecutive layers and wherein the layers are built up with the minimum number of windings in the first, second, and third layer as stated above, is particularly effective filtering oil, for particles having a diameter or average particle size in the range from 0.5 μm to 50 μm, without having using excessive pressure, but merely by letting the fluid flow freely through the filter at a pressure that is usually used in engines, power transmissions, such as hydraulics, gears, valves etc.
In one embodiment according to the invention each of the three layers have been wound in accordance with a winding pattern that is different from the winding pattern of the other layers. Hereby is achieved a filter wherein each layer mainly filters particles from the fluid up to a certain size. Thus, allowing a more effective utilization of the total volume of the filter for the filtering purpose.
In another embodiment, the first layer comprises preferably less than 20 windings of the yarn, the second layer comprises less than 20 windings of the yarn, and the third layer comprises less than 15 windings of the yarn.
In a preferred embodiment, the first layer comprises between 15 and 17 windings of the yarn, the second aspect of the invention the second layer comprises between 15 and 20 windings of the yarn, and the third layer comprises between 10 and 15 windings of the yarn.
In order to facilitate a good flow of the fluid through the filter without applying excessive pressure, each of the three layers of the filter comprises, preferably, less than 45-65 windings of yarn.
One way of providing a particular winding pattern is by using a particular winding angle, and the applicant has found it advantageous if the first layer of yarn has been wound around the outer surface of the core at an angle larger than 55 degrees with respect to an axis parallel to the tubular core, and the second layer of yarn has been wound around the outer surface of the core at an angle larger than 50 degrees with respect to an axis parallel to the tubular core, and the third layer of yarn has been wound around the outer surface of the core at an angle larger than 45 degrees with respect to an axis parallel to the tubular core. Preferably, the angle with which the yarn has been wound around the core is different for two consecutive layers, in order to facilitate winding patterns that are able to trap particles of different sizes.
Preferably, the yarn comprises a mix of natural and synthetic fibers. Since natural fibers are hydrophilic, while synthetic fibers generally are hydrophobic, a filter wherein the yarn is made of a mix of both natural and synthetic fibers has the additional advantage that in addition to being able to filter particles from the fluid, also water may be absorbed by the yarn and thereby filtered from the fluid without having to heat the filter.
In a preferred embodiment, the natural fibers are chosen from a list of fibers comprising cotton and/or wool and the synthetic fibers are chosen from a list of fibers comprising any of the following materials: acryl, polyester, flax, polyamide, acetate and/or viscose. Cotton and wool are cheap natural fibers that are easy to mix with any or a plurality of the synthetic fibers mentioned above. Thus facilitating an effective, yet cheap yarn that for the filter.
In one embodiment according to the invention, the yarn comprises less than 15% natural fibers. In another embodiment, the yarn comprises more than 45% acryl. In yet another embodiment the yarn comprises more than 20% polyester, and in yet even another embodiment the yarn comprises more than 25% flax.
Preferably, the yarn comprises between 4% and 5% polyamide or between 5% and 10% polyamide.
In an alternative embodiment, the yarn comprises more than 2% viscose, or between 2% and 4% viscose.
Another embodiment of the first aspect of the invention the length of yarn is wound in a series of at least four layers around an outer surface of the core, at least three of the at least four layers being wound in accordance with different winding patterns, the yarn comprising a mixture of natural and synthetic fibers, wherein the natural fibers constitutes less than 15% of the yarn, and the reminder constitutes fibers or a mix of fibers made from one or more of the following synthetic materials: acryl, polyester, flax, polyamide, acetate.
By providing a layered filter with a yarn that is made from a mix of natural constituting less than 15% (of the yarn) and synthetic fibers made from any of the synthetic materials mentioned above, a filter is achieved that is particularly effective for filtering particles having a diameter or an average particle size between 0.5 μm and 50 μm from oil.
In one embodiment according to the invention each of the three layers have been wound in accordance with a winding pattern that is different from the winding pattern of the other layers. Hereby is achieved a filter wherein each layer mainly filters particles from the fluid up to a certain size. Thus, allowing a more effective utilization of the total volume of the filter for the filtering purpose.
According to a preferred embodiment of any of the aspects of the invention, the outer surface of the tubular core is covered with a fluid permeable sheet that covers the core at least one time, the sheet being placed between the outer surface of the core and the first layer of yarn. The sheet is preferably a piece of textile, preferably a tightly woven textile.
According to an embodiment of the invention, the filter may further comprise a housing that completely encloses the tubular core and yarn. The housing further comprises a first opening that is fluidly connected to the hollow interior of the tubular core, and a second opening that is fluidly connected to the layers of yarn. Preferably, the second opening functions as a fluid inlet, and the first opening functions as a fluid outlet. Hereby is achieved a self-contained unit that that may be adapted to be mounted in connection with a power transmission system, such as an engine, hydraulics, gears, valves etc. Furthermore, this self-contained unit may be used as a bypass filter for providing additional filtering in already existing installations and power transmission systems. The housing is preferably made from metal.
In order to facilitate easy exchange of the filter, e.g., when it is worn out, without having to change the whole housing as well, the housing may comprise a container and a cap that is releasable attached to the container.
In one embodiment of any of the aspects of the invention, the first opening is placed in the cap and the second opening is placed in the container, and in another embodiment the second opening is placed in the cap and the first opening is placed in the container.
However, in a preferred embodiment of any of the aspects of the invention both the first and the second openings are placed in the cap. Hereby is achieved an embodiment wherein the filter may be replaced in an easy manner without having to unplug one or both if the first and second openings of the housing. The container may for example just be screwed of the cap and the filter replaced. Alternatively, both the first and second opening is placed in the container.
According to an embodiment of any aspects of the invention, the longitudinal extension of the yarn-covered core is between 4-8 times the total radial thicknesses of the layers as measured from the outer surface of the tubular core. The dimensions that are chosen in any particular case may be chosen in dependence of the capacity needed, i.e. how much fluid is needed to be filtered pr. hour. For example, a filter according to any aspects of the invention having a longitudinal extension between 24 cm and 70 cm will be suitable for filtering up to 300-2500 l/h (liters/hour).
The above mentioned and further objects are achieved by a second aspect of the invention, pertaining to a method of manufacturing a filter as described above, the method comprising the steps of
In an embodiment, the method further comprises the step of winding each of the three layers in accordance with pre-programmed winding patterns different from the winding patterns of the other layers.
In a further embodiment, the method further comprises the steps of
In a further embodiment, the method further comprises the steps of
In a further embodiment, the method further comprises the steps of
In a further embodiment of the method, the yarn comprises a mix of natural and synthetic fibers.
In a further embodiment of the method, the natural fibers are chosen from a list of fibers comprising cotton and/or wool and wherein the synthetic fibers are chosen from a list of fibers comprising any of the following materials: acryl, polyester, flax, polyamide, acetate.
In an embodiment of the method, the yarn comprises less than 15% natural fibers, and in a further embodiment of the method, the yarn comprises more than 45% acryl, in a yet further embodiment of the method, the yarn comprises more than 20% polyester, and in an yet even further embodiment of the method, the yarn comprises more than 25% flax.
In a further embodiment of the method, the yarn comprises less than 10% polyamide or between 4% and 5% polyamide.
In a further embodiment, the method further comprises the step of varying the winding resistance of the yarn by varying the speed at which the yarn is fed through the head relative to the speed of rotation of the tubular core.
In a further embodiment, the method further comprises the step of winding the yarn around the outer surface of the core with different winding resistance in at least two of the three layers.
In a further embodiment, the method further comprises the step of winding the yarn of the first and third layer around the outer surface of the core with a winding resistance that is larger than the winding resistance used for the second layer.
In a further embodiment, the method further comprises the step of winding the yarn of the first layer around the outer surface of the core with a winding resistance that is larger than the winding resistance used for the second layer, and winding the yarn of the second layer around the outer surface of the core with a winding resistance that is larger than the winding resistance used for the third layer.
In a further embodiment, the method further comprises the step of covering at least in part the outer surface of the tubular core with a fluid permeable sheet prior to the step of winding the yarn onto the core.
The above mentioned and further objects are achieved by a method for removing water from oil, the method comprising the following steps:
According to an embodiment of the method of removing water from oil, the oil is pressurized to a pressure of between 8 bars to 40 bars before injecting it into the evaporation camber through the plurality of compression tubes.
According to a further embodiment of the method of removing water from oil, the compression tubes have rifled barrels for imparting a rotational movement to the oil that is injected into the evaporation chamber through the compression tubes.
The above mentioned and further objects are achieved by a method for removing water from oil, the method comprising the following steps:
According to an embodiment of the method of removing water from oil, the oil is pressurized to a pressure of between 10 bars to 20 bars before injecting it into the evaporation camber through the plurality of atomizing nozzles.
According to a further embodiment of the method of removing water from oil, the nozzles have rifled barrels for imparting a rotational movement to the oil that is injected into the evaporation chamber through the nozzles.
The method of removing water from oil, may further comprise the steps of,
In a preferred embodiment of the method of filtering oil, said method may utilize a filter manufactured according to any of the above-mentioned embodiments of manufacturing a filter according to the invention.
The above mentioned and further objects are also fulfilled by a filter battery comprising a plurality of filters as described above, said filters being fluidly connected in series for consecutive filtering of oil, through said filters. The oil is first filtered through the first filter in the series, and then through the next, etc., until it reaches the last filter, from which it leaks back to the circuit from where it originated.
A further understanding of the nature and advantages of the present invention may be realized by reference to the remaining portions of the specification and the drawings. In the following, preferred embodiments of the invention is explained in more detail with reference to the drawings, wherein
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. The invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout. Like elements will, thus, not be described in detail with respect to the description of each figure.
Preferably, the first layer 15 comprises between 15 and 17 windings of the yarn 12, the second layer 17 comprises between 15 and 20 windings of the yarn 12, and the third layer 10 comprises between 10 and 15 windings of the yarn 12.
One way of providing a particular winding pattern in the illustrated filter element 10 is by using a particular winding angle λ. The applicant has found it advantageous if the first layer 11 of yarn 12 has been wound around the outer surface 16 of the tubular core 2 at an angle λ larger than 55 degrees with respect to an axis 12 parallel to the longitudinal extension of the tubular core 2, and the second layer 17 of yarn 12 has been wound around the outer surface 10 of the tubular core 2 at an angle λ larger than 45 degrees with respect to an axis 14 parallel to the longitudinal extension of the tubular core 2, and the third layer 10 of yarn 12 has been wound around the outer surface 16 of the tubular core 2 at an angle λ larger than 40 degrees with respect to an axis 14 parallel to the longitudinal extension of the tubular core 2. Preferably, the angle λ with which the yarn 12 has been wound around the tubular core 2 is different for two consecutive layers 10 and 12, in order to facilitate winding patterns that are able to trap particles of different sizes.
In another (not illustrated) embodiment, the filter element 10 may comprise additional layers, for example, the illustrated layer structure of 3 layers 11, 13 and 15 could be repeated for a suitable number of times.
Hereby is achieved a self-contained filter 27 that that may be adapted to be mounted in connection with a power transmission system, such as an engine, hydraulics, gears, valves etc., which is able to remove both solid particle contaminants as well as water from the oils. Furthermore, this self-contained filter 27 may be used as a bypass filter for providing additional filtering in already existing installations and power transmission systems. The housing 17 is preferably made from metal, such as Aluminum.
In order to facilitate easy exchange of the filter element 10, e.g. when it is worn out, without having to change the whole housing 17 as well, the housing 17 may comprise a container 23 that is releasable attached to the housing 17. This releasable attachment could for example be provided by the illustrated threading 19.
In the illustrated embodiment both the drainage pipe 22 and the inlet opening 24 are placed in the cap 20. Hereby is achieved an embodiment wherein the filter element 10 may be replaced in an easy manner without having to unplug one or both if the drainage pipe 22 and inlet opening 24 of the housing 17. The container 23 may for example just be screwed of the cap 20 and the filter element 10 replaced.
According to an embodiment the longitudinal extension 6 of the yarn 12 covered tubular cores 2 is between 5-10 times the total radial thicknesses 21 of the layers as measured from the outer surface 16 of the tubular core 2. The dimensions that are chosen in any particular case may be chosen in dependence of the capacity needed, i.e. how much oil is needed to be filtered pr. hour. For example a filter 10 having a longitudinal extension 6 between 24 cm and 30 cm will be suitable for filtering up to 250-500 l/h (liters/hour) of oil, while a filter 10 that has a longitudinal extension 6 between 45 cm and 60 cm will be suitable for filtering up to 1000-1500 l/h.
The illustrated main block 81 further having an inlet pipe 24 that in one end 79 is fluidly connected to a container, i.e. the housing 17, adapted to temporarily store the oil to be filtered, and in the other end being fluidly connected to a distillation unit 81, said distillation head comprising a plurality (only three visible) of compressing tubes 78 for injecting the oil into a evaporation chamber 80. In the wall of the evaporation chamber 80, there is provided an inlet 82 for blowing air or an inert gas into said evaporation chamber 80.
By providing a plurality of compression tubes 78 for injecting the oil into the evaporation chamber 80, the oil is compressed as a liquid into the evaporation chamber 80. Due to the different thermodynamic properties of the oil and the water, they react differently to changes in heat and pressure. These vaporized contaminants; (steam) is then blown out of the evaporation chamber 80 through an opening in the cap 91, while the oil is drained out in liquid form through a drainage pipe 22. A plurality of compressing tubes 78 is used in order to ensure an adequate flow rate, and the actual number of compressing tubes 78 needed may be chosen in dependence of the particular application of the inventive filter 27.
When oil enters the housing 17 through the inlet opening 24 in the cap 20 of the housing 17 it will flow into the hollow interior 25 of the container 23. The oil will then flow through the layers (not illustrated explicitly) of yarn 12 along the total radial thickness 21 of the yarn 12 and into the hollow interior 8 of the tubular core 2 via the apertures 4. During its flow through the layers (not explicitly illustrated in this figure, but see for example
However, there is a delicate balance in selecting proper barrel opening sizes, because the opening size controls both the extent of separation and the flow rate through the filter 27. Selection of the barrel opening 88 also controls the pressure differential between the oil inlet 24 and the evaporation chamber 80.
The compression tube 78 have preferably a barrel 90 that is rifled in order to thereby impart a rotational motion to the compressed injected oil and thereby enhance the separation (evaporation) of contaminants from them.
In a preferred embodiment the length of the barrel 90 of each of the compression tubes 78 is between 4 mm and 40 mm.
The technical industries have particular difficulties with water contaminants in oils for lubrication and different transmissions or transformers (hydraulics, gears, valves etc.). These water contaminants mainly arise from condensation, leaks, frost, etc. Non combusted fuel remnants, acids and eventually other alien liquids can also be present, where especially acids may be formed in the presence of water.
Advantageously, the oil is pressurized, e.g. to a pressure of between 8 bars and 40 bars, before it is injected through the compressing tubes 78.
Also shown is the start block 89 and end block 72.
The yarn 12 comprises a number of fibers 26, 28 and 30 (of which only three have been given designation numbers in order to increase the intelligibility of the figure).
Preferably, the yarn 12 comprises a mix of natural and synthetic fibers. For example in the illustrated embodiment, the fibers 26 and 30 may be natural, while the fiber 28 may be synthetic. Since natural fibers 26 and 30 are hydrophilic, while synthetic fibers 28 generally are hydrophobic, a filter element 10 wherein the yarn 12 is made of a mix of both natural (26 and 30) and synthetic (28) fibers has the additional advantage that in addition to being able to filter particles from the oil, also water may be absorbed by the yarn 12 and thereby filtered from the oil.
In a preferred embodiment, the natural fibers 26 and 30 are chosen from a list of fibers comprising cotton and/or wool and the synthetic fibers (28) are chosen from a list of fibers comprising any of the following materials: acryl, polyester, flax, polyamide, acetate and/or viscose. Cotton and wool are cheap natural fibers that are easy to mix with any or a plurality of the synthetic fibers mentioned above. Thus facilitating an effective, yet cheap yarn 12 for the filter element 10.
In one embodiment according to the invention, the yarn 12 comprises less than 15% natural fibers. In another embodiment, the yarn 12 comprises more than 45% acryl. In yet another embodiment the yarn 12 comprises more than 20% polyester, and in yet even another embodiment the yarn 12 comprises more than 25% flax.
Preferably, the yarn 12 comprises less than 10% polyamide or between 4% and 5% polyamide.
In an alternative embodiment, the yarn 12 comprises more than 2% viscose, or between 2% and 4% viscose.
In a preferred embodiment of any of the filter elements 10 illustrated in any of the
The winding resistance may be adjusted by varying the speed at which the yarn 12 is fed through the head 44 relative to the speed of rotation of the tubular core with respect to the axis 14. The winding machine 42 preferably automatically controls this adjustment of the winding resistance.
In another embodiment of any of the filter elements 10 illustrated in any of the
While it has not been illustrated in any of the figures, the outer surface 16 of the tubular core 12 illustrated in any of the figures may also be covered with a fluid permeable sheet that covers the outer surface 16 of the tubular core 2 at least one time. The sheet, thus being placed between the outer surface 16 of the core 2 and the first layer 11 of yarn 12. The sheet is preferably a piece of textile, preferably a tightly woven textile.
In the following more specific examples of filter elements 10 are given, wherein
In a preferred embodiment of a filter element 10 as illustrated in any of the
In another preferred embodiment of a filter element 10 as illustrated in any of the
In yet another preferred embodiment of a filter element 10 as illustrated in any of the
The method illustrated by the flow diagram in
In the following is given a list of reference numbers used in the detailed description of the invention.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/NO2015/050015 | 1/23/2015 | WO | 00 |
