US2592849A - Filter - Google Patents

Description

R.. A. BALLEY FILTER 2 SHEETS--SHEET l April 15, 1952 Filed May 2, 1949 R. A. BALLEY April 15, 1952 FILTER 2 SHEETS- SHEET 2 Filed May 2. 1949 //v VEN 7-0 R arr),

Patented Apr. 15, 1952 FILTER Ronald A. Bailey, Bletchley, England, assignor to Wipac Filtration Limited, Bletchley, England, a company of Great Britain Application May 2, 1949, Serial No.y 90,923 In Great Britain May 12, 1948 8 Claims. l

This invention relates to filters for liquids, and it is especially but not exclusively concerned with filters for fuel supplied to internal-combustion engines and for lubricating oil in pressure circulation systems of such engines and other machines.

An object of this invention is to provide a lter which is simple, efficient, inexpensive and easily reconditioned and which can be made in various capacities with standard parts.

Another object is to obviate the need for sealing washers fitting against the ltering elements.

Another object is to provide an improved filtering element.

According to this invention, a liquid filtering element consists of a perforated frustoconical annulus of stili sheet material having projections on its inner surface and an annulus of sheet filtering material fitted as a lining to the perforated annulus and held in place by two annular flanges on the perforated annulus overlying the radially inner and outer borders of the filtering annulus. The perforated annulus may be for example a sheet metal pressing, the projections being concentric pressed annular ridges. The iiltering annulus may consist of a layer of wire gauze adjacent to the perforated annulus and acting as a support for a layer of felt or other easily pliable sheet filtering material.

Also according to this invention, a iilter for liquid includes a stack of at least one pair of frustoconical ltering elements as hereinbefore specilied and pressed together base to base by means of a tie passing co-axially through the stack and having two annular abutments engaging the radially inner borders of the end elements of the stack, a vessel enclosing the stack, and two liquid ducts communicating respectively with the enclosed spaces inside and outside the stack.

The tie may be formed by a tubular duct which lits the central apertures in the elements and so ensures their co-axial relationship and which has one or more ports communicating with the space within each pair of elements.

In one form of the improved filter, the tie is a tubular screw engaged in an internally screwthreaded port in a body member, the said two abutments being formed respectively on the body and on a head on the screw. In another form the tie is a tube having flanged ends forming the said abutments.

Further according to this invention a iilter for liquid includes a stack of at least one pair of frusto-conical filtering elements as hereinbefore specified and pressed together base to base by means of a perforated tubular tie having one end closed, said tie passing co-axially through the stack and having two annular abutments engaging the radially inner borders of the end elements of the stack, a vessel enclosing the stack, liquid inlet and outlet ducts communicating respectively with the open end of the tie and with the enclosed space outside the stack, and' biasing means urging the stack axially in such a direction as to close the junction between the inlet duct and the open end of the tie.

Two embodiments of the invention as applied to a fuel-oil filter and to a full-flow lubricating oil filter for internal combustion engines will now be described, by Way of example, with reference to the accompanying drawings wherein:

Figure 1 is a section in elevation of a fuel-oil filter taken along the line I--I in Figure 2.

Figure 2 is a View in' elevation of the iilter to the same scale as in Figure 1.

Figure 3 is a diagrammatic section of one of the filtering elements appearing in Figures 1 and 2 and drawn to a larger scale. f

Figure 4 is a view in elevation of the same filtering element drawn to a scale intermediate between those of Figures 1 and 3.

Figure 5 is a diagrammatic section in elevation of a full-flow lubricating oil iilter according to the invention, and

Figure 6 is a section taken along the line 6--6 in Figure 5.

The iilter body I0 is a substantially circular die-casting having diametrically opposed radial inlet and outlet sockets II and I2 respectively. The body is mounted with its axis vertical and may be attached to a suitable support by screws passing through screw holes I3 and I 4 in a bracket I5 which is integral with the iilter body II). A sealing washer I6 is located in an annular seating in the underside of body Ill. A metal or glass bowl I'I is held with its edge pressing on to the sealing washer I6 by means of a wire stirrup I8 having its end-s pvoted in housings I9 and 20 integral with the body I0. The bowl is. pressed against the sealing washer by a nut 2I working on a jacking screw '22 which .has a slotted por-I tion 23 embracing a iiat on the stirrup I8. 'I'he nut 2l has an extension 24 forming an annular groove whose sides embrace the borders of an aperture in the bottom of a cup 25 against which the nut 2l presses; the extension retains the cup on the nut when the cup is not under pressure from the nut. The edge of the cup 25 surrounds a depression 28 in the bowl I 1; the depression serves to prevent movement of the cup 25 transversely to the axis of the lter whilst the nut 2| is tightened. The lip of the bowl I1 is narrow and consequently little pressure is required to seat it on the sealing washer I6 so as to give a tight seal. The outlet socket l2 communicates by means of a passage 21 with an internally threaded hollow cylindrical boss 28 projecting downwards from the middle of the body. The inlet socket Il communicates with a port 29 in the under side of the body between the outlet boss 28 and the sealing washer i6.

A tubular tie 30, having a diameter of A; in., which is smaller than the external diameter of the tubular boss 28, is provided at its upper end with a screwed spigot 3| engaged in the boss. At the lower end the tie is closed by a hexagonal head 32 providing a flat annular facing 33 on its upper side. The filtering elements are identical, and any desired even number is provided, according to the capacity of the filter. Each element consists of-a truste-conical pressing 34 of soft sheet aluminum 21A; in. in diameter and 0.015

to 0.018 in. thick, the central aperture being 5/8 in. in diameter. The apex angle of the cone is 158". Two annular ribs 35 and 36 of arcuate section and liga in. deep are pressed in the cone so as to project on its inner surface. Each of the three annular zones 31,38 and 39 has eight perforations 40 of 1/8 in. diameter disposed symmetrically about the axis of the cone. The filtering media consist of an annulus 4I of fine-mesh wire gauze adapted to retain water and placed adjacent to the ribs 35 and 36 and an annulus 42 of felt lying against the gauze 4I. The edges 43 and 44 of the metal cone are turned inwards and towards each other so as to overlie the borders of the felt and the gauze and thus hold the filtering media in the cone.

The uppermost filtering element is placed concave side downwards with its edge 45 abutting the tubular boss 28. The next lower ltering element is placed concave side upwards with its edge 46 abutting the uppermost element. Any desired numberof pairs of similarly juxtaposed iiltering elements are placed on the tubular tie 30, the edge 45 of the lowest element abutting the annular facing 33 on' the head 32 of the tie 30. The length of the tie is such that the filtering elements are under axial compression.

In operation, liquid enters the bowl through the inlet Il and the port 29 and passes through the perforations 40 in the cones. Since the iiltering media are spaced by the ribs 35 and 36 from the general surface of the cones, the liquid has easy access to substantially the whole oi the filter surface. Filtered liquid passes through holes 41 in the interior of the tie 30 to the outlet I2.

Exhausted filter elements can be removed by removing the bowl l1 and unscrewing the tie 30, and are replaced by new elements. A bleed screw provided with a sealing washer 1| is provided in the body for equalising the internal and external pressures of the filter before the filter is opened.

The embodiment shown in Figures 5 and 6 is suitable for use as a full-now lter in the lubrication system of an internal-combustion engine.

The body of the lter is a die-cast pot 4i havingan inlet socket 48 and an outlet socket 49 integral therewith. A cover 50 is also a die casting and is fastened to the body by eight studs 5i and a stud 5 l co-operating with nuts 52 and a capped nut 52', the studs 4being disposed equidistantly around its circumference. A sealing washer 53 is provided between the body and the cover. The inlet socket 48 communicates with a bore 54 in a central boss 55 on the cover through a passage 56 and a chamber 51. The stud 5I passes through the chamber 51. A sealing washer 59 is provided between the n-ut 52' and the cover 50. The clamping action of this stud ensures a liquid-tight seal in the chamber 51. An even number of filter elements 60 are retained on a tubular tie 6| by flanges 62 and 63 formed at its ends. The tie has outlet holes 64 and is closed at its -lower end by a cup-shaped member 65 which is slidable upon a boss 66 integral with the body 41. A helical compression spring 61 surrounds the boss 66 and presses against the flange 63 on the tie. The sides of the cup-shaped member 65 extend beyond the flange 63 and serve to prevent sideways movement of the spring 61. The spring presses the flange 62 cn to an annular seating 68 on the cover and prevents the escape of liquid through longitudinal channels 89 in the boss 55. When the oil is cold or the iilter elements are choked, the oil pressure drop developed across the filter causes the stack consisting of the tie and the filtering elementsl to move axially against the force exerted by the compression spring 61 and to open the channels B9 so that oil can pass through them to the outlet port 49. While in these circumstances the filter will pass unfiltered oil, there is substantially no risk that matter already trapped by the filter will re-enter the lubrication system, since this matter is confined by the oil pressure within the double-conical chambers inside the iilter stackl and is therefore not likely to work back through the tie tube into the by-passing oil stream. This filter is reconditioned by renewing the complete sub-assembly of iilter elements and tie tube.

I claim:

1. A lter for liquid including a vessel, the vessel enclosingV a stack of at least one pair of frusto-conical filtering elements each filtering element consisting' of a pressed sheet metal perforated frusta-conical annulus having projections on its inner surface, and an armulusl of sheet filtering material fitted as a lining to the inner surface of the perforated frusta-conical annulus and held in place by two annular flanges formed by unperforated borders of the perforated annulus bent inwards and towards each other so as to overlie the radially inner and outer borders of the filtering annulus, the iiltering elements being pressed together base to base by means of a tie consisting of a headed tubular screw engaged in an internally-screw-threaded port in said vessel, said screw passing co-axially through and fitting central apertures in the said elements, said screw furthermore having an annular abutment formed on its head and having at least one port communicating with the space within each pair of elcments, a second annular abutment being formed on the vessel adjacent said internally threaded port, the annular abutments engaging the radially inner borders of the end elements of the stack, and two liquid ducts communicating respectively with the enclosed space outside the stack and with the interior of said screw.

2. A filter for liquid including a vessel, the vessel enclosing a stack of at least one pair of filtering elements, each filtering element consisting of a pressed sheet metal perforated frustoconical annulus having concentric annular ridges formed on its concave surface and having a iiltering annulus fitted as a lining and held in place by two annular flanges on the perforated annulus overlying the radially inner and outer borders of the filtering annulus, said filtering annutral apertures in the said elements, said screw furthermore having an annular abutment formed on its head and having at least one port coznmunicating with the space within each pair of i elements, a second annular abutment being formed on the vessel adjacent said internally threaded port, the annular abutmentsengaging the radially inner borders of theend elements of the stack, and two liquid ducts communicating` respectively with the enclosed space outside the stack and with the interior of said screw.

3. A liquid filtering element consisting of a perforated frusta-conical annulus of stili sheet material having projections on its inner surface and an annulus of sheet vfiltering material fitted A as a lining to the inner surface of the perforated i i'rusto-conical `annulus and held in place by two annular anges formed by ini-perforated borders of the perforated annulus bent inwards and inner and outer borders of the filtering annuli.

7. A filter for liquids including a stack of at least one pair of filtering elements, each of said elements consisting of a perforated frusto-conical annulus of stili sheet material having projections on its inner surface and an annulus of sheet filtering material fitted as a linin-g to the inner surface of the perforated frusto-conical annulus and held in place lby two annular anges formed by imperforated borders of the perforated annulus bent inwards and towards each other so as to overlie the radially inner and outer borders of the filtering annulus, said elements being placed together base to base, said filter also including a tie passing co-axially through said stack and having two annular abutments engaging the radially inner borders of the end elements of the stack, a vessel enclosing the stack, and

two liquid ducts communicating respectively with towards each other so as to overlie the radiallyl A inner and outer borders of the filtering annulus.

4. A liquid filtering element consisting of a per forated frusto-conical sheet metal annular pressing having concentric pressed annular ridges pro jecting on its inner surface and an annulus of sheet filtering material tted as a lining to the inner surface of said pressing and held in place by two annular flanges formed by borders of said pressing bent inwards and towards each other so Aas to overlie the radially inner and outer borders of the filtering annulus.

5. An oil filtering element consisting of a perforated frusto-conical annulus of stiff sheet material having projections on its inner surface, a primary filtering annulus of wire gauze fine enough to retain water and fitted against said projections on the inner side of said ,stiff annulus V and a secondary filtering annulus of fibrous material tted against the inner side of said gauze annulus, said filtering annuli being held in place by two annular flanges formed integrally with the stili? annulus and projecting towards each other so as to overlie the radially inner and outer borders of the filtering annuli.

6. An oil filtering element consisting of a perforated frusto-conical sheet metal annular pressing having concentric pressed annular ridges projecting on its inner surface, aprimary filtering annulus of wire gauze fine enough to retain water and tted against said ridges on the inner side of said pressing, and a secondary filtering annulus of fibrous material fitted against the inner side of said gauze annulus, said filtering annuli being held in place by two annular flanges formed integrally with said pressing and bent inwards land towards each other so as to overlie the radially -fue of this patent:

the space enclosed in said vessel outside said stackl and with the interior ofsaid stack, the axial spacing of said abutments ,being shorter than the height of said stack in its untied state, so that said elements are compressed by said tie. 8. A filter for liquids including a stack of at.

least one pair of filtering elements, each of said elements consisting of a perforated frusto-conical annulus of stiff sheet material having projections on its inner surface, a primary ltering annulus of wire gauze fine enough to retain water and fitted against said projections on the inner side of said stiff annulus and a secondary filtering annulus of fibrous material fitted againstfthe inner side of said gauze annulus. said filtering annuli being held in place4 by two annular flangesv formed integrally with the stiff annulus and projecting towards each other so as to overlietheV radially inner and outer borders of the filtering` annuli, said elements being placed together base to base, said filter also including a perforated tubular tie passing co-axially through said stack and having two annular abutments engaging the radially inner borders of the end elements of the stack, a vessel enclosing the stack, and two liquid ducts communicating"respectively with space enclosed in said vessel outside said stack and with the interior of said ,tiethe axial spacing of said abutments being shorter than the height of said stack in its untied state. so that said elements are compressed by said tie.

RONALD A. BALLEY.

REFERENCES lCITED The following references are of record in the UNITED STATES PATENTS Number Name Date 1,619,118 Guy et al. Mar. 1, 1927 1,989,795 Fellows Feb. 5, 1935 2,088,199 Gleason `July 27, 1937 2,230,408 Lockey Feb. 4, 1941 2,266,350 Womack Dec. 16, 1941 2,279,423 Vokes Apr. 14, 1942 2,288,532 Knapp June 30, 1942 2,313,612 Alsop Mar. 9, 1943 l2,452,486 OMeara Oct. 26, 1948

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