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CA1269048A - Multiple layer precision wound filter - Google Patents

Multiple layer precision wound filter

Info

Publication number
CA1269048A
CA1269048A CA000485582A CA485582A CA1269048A CA 1269048 A CA1269048 A CA 1269048A CA 000485582 A CA000485582 A CA 000485582A CA 485582 A CA485582 A CA 485582A CA 1269048 A CA1269048 A CA 1269048A
Authority
CA
Canada
Prior art keywords
wind
base
cartridge
ratio
range
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CA000485582A
Other languages
French (fr)
Inventor
Stephen A. Nemesi
James E. Schmitz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kennecott Corp
Original Assignee
Kennecott Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kennecott Corp filed Critical Kennecott Corp
Priority to CA000485582A priority Critical patent/CA1269048A/en
Application granted granted Critical
Publication of CA1269048A publication Critical patent/CA1269048A/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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  • Filtering Materials (AREA)

Abstract

ABSTRACT OF THE DISCLOSURE

A precision wound tubular shaped filter cartridge having a filter medium of multiple wind or layer construction having prealigned and disposed diamond shaped flow passages between winds to permit unrestricted fluid flow paths through the filter medium.

Description

lZ~ )48 MULTILAYER PRECISION WOUND FILTER CARTRIDGE

BACKGROUND OF THE INVENTION
The present invention is directed to new and useful improvements in filter cartridges and in particular to precision wound tubular shaped filter cartridges comprised of helically wound multiple layers of yarn or roving.
It is well known to provide filter cartridges for purifying liquid input streams wherein the cartridge comprises a tubular element having a foraminous core about which layers of spaced convolutions of fibrous filter yarn are precision wound . The yarn is applied in crisscross fashion to form a plurality of diamond shaped filtering passageways from the outer surface of the element to the foraminous core. As fluid passes through the filter element through the diamond shaped passageways dirt particles or the like in the fluid are captured among the fibrous yarn strands which may be napped to provide additional dirt capturing fibers.
In general, precision wound filters are formed by mounting the foraminous core in a horizontal position on a motor driven spindle. One end of the strand of filtering material is tied or otherwise fixed to one end of the sidewall of the core. The strand passes through a guide which is arranged through a gear train or similar arrangement to maintain a precise relationship between rotations of the core and traverse of the guide, to move back and forth along the length of the core, as the core is rotated. As the guide travels in one direction along the rotating core, a spiral or strand is wrapped around the core from one end to the other. When the guide reaches the far end of the core, it reverses in direction and travels back to the beginning point. During this travel in a reverse direction, the core continues to rotate in the same ~irection. In this manner a reverse spiral of strand is 3'~

1~6~

laid down on the core overlaying the original strand spiral, forming a diamond pattern which provide passageways for the fluid to be filtered.
Typical filter cartridges have a foraminous core with a diameter of about 1 - 1/8 inches and an overall diameter of about 2 - 7/1~ inches with a filter medium ti.e. the buildup of fibrous strands on the core) being about 11/16 inches thick. The standard length of the filter cartridge is 10 inches for insertion in a suitable file housing. ~he ratio of circumferential diamond shaped passages to axial diamond shaped passages is usually within the range of about 2 to about 5 whereby for each circumferential diamond there are about 2 to 5 axial diamonds.
Since these filter cartridges are disposable and replaceable once they reach their rated dirt holding capacity there have been many prior art efforts to increase the useful life and dirt holding capacity of these cartridges within the previously mentioned required dimensional restrictions.
In one known type precision wound filter cartridge of the type described it is known to provide a filter medium comprised of layers of different densities (wind geometries) wherein the inner layer or base wind is provided with a greater number of circumferential diamonds than the outer layer or wind to improve the efficiency of the cartridge over mono-layer wound cartridges.
Although these known multi-layer filter cartridges are meant to maintain efficiency and maximize filter characteristics of the cartridge problems are encountered in preventing the plugging of the radial helically disposed flow passageways due to restrictions in the flow patterns of the diamond shaped passageways occurring at the interface between adjacent layers. The communication of passageways and the interlayer restrictions between layers resulted in the loss of efficiency and shortening of the useful life span of the filter cartridge. It was found that in the positioning of layers the roving strands in the more open outer layer restricted access of fluid to the channels in the tighter inner layer adjacent the core. These flow restrictions were found to cause a higher pressure drop and thus a decrease in dirt holding capacity and a plugging of the radial passageway.
It is an object of the present invention to provide a novel multiple layer precision wound filter.
Another object is to provide a novel multilayer filter cartridge having increased dirt holding capacity.
A still further object is to provide a multiple layer filter cartridge wherein flow restrictions between adjacent layers is greatly reduced through novel positioning of the radial flow passages between adjacent layers.
SUMMARY OF_THE INVENTION
The present invention contemplates a novel precision yarn wound tubular shaped filter cartridge of multiple wind or layer construction wherein at least the inner layer or base wind is more tightly wound than the outer layer or wind resulting in a greater number of axial and circumferential diamond shaped flow passages in the inner layer which is wound about a foraminous inner core discharge tube. The present invention contemplates the proper prealignment of flow passages between the flow channels of the inner and outer layer at the interface thereof to avoid flow restrictions and increase dirt holding capacity of the filter cartridge.
The above and other objects and advantages of the present invention will appear more fully hereinafter from a consideration of the detailed description which follows taken together with the accompanying drawings wherein an embodiment of the invention is clearly illustrated.

l2~sa~

DESCRIPTION OF THE DRAWINGS
In the Drawings:
FIG. 1 is a generally schematic perspective view of a multilayer filter cartridge with portions of the outer layer cut away to expose the inner layer; and FIG. 2 is a transverse cross-sectional view of a filter cartridge in accordance with the present invention.
DETAILED DE CRIPTIO
Referring now to the drawings for a more detailed description of the present invention a filter cartridge made in accordance with the present invention is generally indicated by the reference numeral 10 in FIG. 1. Cartridge 10 has a cylindrical inner foraminous core 11 and although ordinarily formed preferably of a perforated tinned steel, other materials such as stainless æteel or plastic may be used.
Cartridge 10 includes a precision wound base wind or inner layer of yarn identified by the reference numeral 12 and an outer wind or layer of yarn identified by the reference numeral 14. In the precision winding of layers 12 and 14 as the fibrous yarn or woven is laid in crisscross pattern by a winder machine a greater number of helical flow passages 16 are provided in base wind 12 than the helical diamond shaped flow passages 18 in outer wind 14. In the embodiment of the present invention shown in FIG. 2 the ratio of circumferential or radial diamonds 16 in the base wind 12 to the circumferential or radial diamonds 18 in outer wind 14 is a ratio of 19 to 11 with the diamond shaped passages 18 of the outer wind 14 of a greater size than the diamonds of the base wind 12.
Although not shown in a filter cartridge 10 of a standard ten inch length it is well known that the ratio number of axial or longitudinally situated diamond shaped passages to circumferential diamond shaped passages are about 2 to 5 axial diamonds. The number of diamonds and layer ratio of dia~onds between the base wind and outer wind lZ~9(J'~8 of a cartridge being selected in accordance with the micron rating for the cartridge for the selected fluid to be filtered. The micron rating is defined as the point at which 90~ of a specific size of dirt particle is removed from the fluid passing through the filter. In the cartridge of FIG. 2 assuming the micron rating is 10 the ratio of radial to axial diamonds in the base wind 12 is 11 - 36 and in the outer wind 14 the ratio is 19 to 66. A suggested chart is as follows:
MICRON RATING BASE WIND OUTER WIND
RADIAL AXIAL RADIAL AXIAL

3 25 - 87 12 - 39.5 23 - 80 12 - 39.5 17 - 58 7 - 23.5 The structure thus far described represents known structure for filter cartridges of the type for example as disclosed in co-pending application Serial No. 447,177 filed December 6, 1982 entitled "Multiple Layer Precision Wound Filter". It is also known that a filter cartridge will fail and require replacement when the cartridge is clogged and the pressure drop across the filter becomes excessive. In these cartridges the dirt is entrapped in the filter strands within the flow passageways and in known multiple layer type cartridge although the outer layer is effective to entrap a significant number of dirt particles a clogging of the passage occurs at the transition or interface of flow passage from the outer wind to the base wind.
It was found that by prealigning the exit flow of the circumferential flow passages 18 of outer wind 14 with the entry openings of passages 16 of base wind 12 rather than permit random positioning of the interface between the base dnd outer winds achieved maximum dirt holding capacity for the filter cartridge can be achieved. In forming a yarn a ;sa~8 cartridge the roving or yarn is applied to a rotating core while traversing it along the length thereof with a cam or guide. ~he wind pattern is developed by holding the ratio speeds of the rotating core and transversing cam constant and the wind patterns are changed by changing the latter ratio. Typically winders hold these ratios constant by using a specified number and combination of gears in a known manner to connect the core and the cam or by electronically controlling the speeds of motors driving the core and cam.
If a multiple layer cartridge is wound differential gear boxes or electronic switching mechanisms are used to change the ratio at completion of the base wind.
In known multilayer cartridge forming processes, the diamond pattern is changed from that of the base wind to that of the outer wind as the winder traverses the length of the cartridge in an area referred to as a coasting area. In this coasting area, the ratio of the core to traverse speeds is momentarily uncontrolled and the winder is free to coast.
It was found that as a result of the change over in diamond patterns in the coasting area, the random alignment of flow passages between base and outer winds was effected.
It is also known that in such processes that there is a transition zone at each end of the cartridge where the reversal of the roving takes place. It was found that if the ratio change was effected in the transition zone that the proper alignment of helical flow passages can be controlled. Since for any given winder device both the length of the transition zone and the time to make the ratio change are constant proper position for ratio change is accomplished by matching the winder traversing speed to the transition zone length and causing the change to begin as the roving enters the transition zone with proximity switches at the end of the cartridge activated for changing the mechanism at the appropriate predetermined time.
It will be apparent from the foregoing description that the novel filter cartridge and means for aligning flow 90'18 passages has many advantages in use. One advantage is that the flow pattern from outer wind to base wind to the foraminous core is unrestricted and permits increased dirt holding capacity for a filter cartridge.
Although one embodiment of the present invention has been illustrated and described in detail it is to be expressly understood that the invention is not limited thereto. Various changes can be made in the design and arrangement of parts without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art.

Claims (17)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR PRIVILEGE
IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A precision helically wound filter cartridge of yarn or roving having a micron rating in the range of 1 to 30 comprising (a) a helically wound base wind of diamond shaped passages of filter yarn material wound onto a cylindrically shaped foraminous core in a crisscross path using a wind number in the range of about 17 to about 39;
(b) a helically wound second wind of diamond shaped passage of filter yarn material wound over said base wind in a crisscross path having a different wind number than said base wind number selected in the range of 7 to 21, forming an outer wind wherein the diamond shaped flow passages in said outer wind are lesser in number than said base wind;
(c) the flow passages at the interface of said winds being aligned one with the other to provide unrestricted flow paths between said base and outer winds.
2. The cartridge of claim 1 wherein said wind number of said base wind to said outer wind is a ratio of about 31 to 7.
3. The cartridge of claim 1 wherein the micron rating of the cartridge is 10 and the wind number of said base wind to said outer wind is a ratio of about 19 to 11.
4. The cartridge of claim 1 wherein the micron ratio of the cartridge is 3 and the wind number of said base wind to said outer wind is a ratio of about 25 to 12-21.
5. The cartridge of claim 1 wherein the micron ratio of the cartridge is 2 and the wind number of said base wind to said outer wind is a ratio of about 39 to 13.
6. The cartridge of claim 1 wherein the wind number for the base wind is in the range of 17 to 31 and the wind number for the outer wind is in the range of 7 to 13.
7. The filter cartridge of claim 1 wherein the circumferential flow passages of said base wind at said interface are arranged in generally unobstructed flow relationship with a lesser number of flow passages in said outer wind.
8. The filter cartridge of claim 1 wherein said ratio of axial diamond shaped passages to the circumferential diamond shaped passages is in the range of 5 to 2 in each of said winds.
9. The caartridge of claim 1 wherein the ratio of circumferential diamond shaped passages of said base wind to said outer wind is in the range of 19 to 9 and the micron rating is in the range of 10 to 20.
10. A method of making a precision helically wound filter cartridge of yarn or roving having a micron rating in the range of 1 to 30 comprising (a) helically winding by a precision winder a base wind of diamond shaped passages of filter yarn material onto a rotating cylindrically shaped foraminous core in a crisscross path using a wind number in the range of about 17 to about 39;
(b) helically winding by the precision winder a second wind of diamond shaped passage of filter yarn material over said base wind in a crisscross path having a different wind number than said base wind number selected in the range of 7 to 21 to form an outer wind wherein the diamond shaped flow passages in said outer wind are lesser in number than said base wind;
(c) switching the ratio of the core rotation speed to the winder speed in a coasting zone at one end of the core prior to commencing the laying of said outer wind and prior to completion of said base wind, and (d) reversing the direction of the yarn in a predetermined transition zone at said core end to align said flow passages at the interface of said winds one with the other to provide unrestricted flow paths between said base and outer winds.
11. The method of claim 10 wherein the winder is switched in a transition zone of 1/4 to 1/2 inches in length at the end of said filter cartridge.
12. The method of claim 11 wherein said wind number of said base wind to said outer wind is a ratio of about 31 to 7.
13. The method of claim 11 wherein the micron rating of the cartridge is 10 and the wind number of said base wind to said outer wind is a ratio of about 19 to 11.
14. The method of claim 11 wherein the micron rating of the cartridge is 3 and the wind number of said base wind to said outer wind is a ratio of about 25 to 12-21.
15. The method of claim 11 wherein the micron rating of the cartridge is 2 and the wind number of said base wind to said outer wind is a ratio of about 39 to 13.
16. The method of claim 10 wherein the wind number for the base wind is in the range of 17 to 31 and the wind number for the outer wind is in the range of 7 to 13.
17. The method of claim 16 wherein the winder is switched in a transition zone of 1/4 to 1/2 inches in length at the end of said filter cartridge.
CA000485582A 1985-06-27 1985-06-27 Multiple layer precision wound filter Expired - Fee Related CA1269048A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA000485582A CA1269048A (en) 1985-06-27 1985-06-27 Multiple layer precision wound filter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA000485582A CA1269048A (en) 1985-06-27 1985-06-27 Multiple layer precision wound filter

Publications (1)

Publication Number Publication Date
CA1269048A true CA1269048A (en) 1990-05-15

Family

ID=4130855

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000485582A Expired - Fee Related CA1269048A (en) 1985-06-27 1985-06-27 Multiple layer precision wound filter

Country Status (1)

Country Link
CA (1) CA1269048A (en)

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