US 2084433 A
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June 22, 1937. F. 'Q L, CHORLTN 2,084,433
FILTER, STRAINER, AND THE ,LIKE
Filed Oct. 12, 1935 M /ff/f wf Y@ Patented June 22, 1937 UNITED STATES PATENT OFFICE pplication October 12, 1935, Serial No. 44,794
' In Great Britain October 27, 1934 6 Claims. (Q1. 210-169) 'Ihis invention relates to filters or strainers, and more particularly to lters or strainers for separating very fine solid particles from oil.
I have illustrated my invention in the accompanying drawing, in which:-
Figs. 1 and 2 show a cage construction suitable for use in that type of lter in which the cage on which the wire is wound is fixed in locating seatings in the filter casing so that the filteringl medium is interposed between the inlet and the outlet;
Fig. 1 being a sectional elevation on the line I-I of Fig. 2; and
Fig. 2 a plan, the left-hand half showing the casing and cover in medial section, and the righthand half showing the casing and cover in medial section and also showing the cage in section on the line II-,II of Fig. 1.
Fig. 3 is an elevation of a rotatable vfiltering unit showing a method of cleaning.
Figs. 4 to 11 illustrate cross-sections of wire which may be employed in carrying out the invention.
Fig. 12 illustrates to a considerable enlarged scale a fragmentary section on the plane XII- XIIof Fig. 1 as shown to a smaller scale at :c of Fig. 2, and
Figs. 13 and 14 are views similar to Fig. 12 and show grooves modified to suit wires of semicircular and trapezoidal shape. Y
Referring first toFigs. 1 and 2;-
A is a cage or former comprising a cylindrical portion al having externally projecting longitudinally disposed ribs a2, forming water-ways a3; at opposite ends the ribs a2 are connected by flanges a4 which fit with suitable jointing, in seatings bi and b2 of the filter casing B. In the outer faces a6 of theribs a2 which are of cylindrical conguration, grooves are cut which form interrupted portions of a helical groove running from end to end oi.' the cage, the pitch of which is slightly greater than the maximum transverse dimensions oi' the wire employed; if a wire of triangular cross-section (as shown in Fig. 4) is employed, a V-shaped groove (as shown in Fig. 12) would be cut, the depth of the groove being less than the distance from the apex of the triangle (Fig. 4) to the base thereof; a portion of the wire winding is shown at C; the ends oi' the wire are suitably secured and the cage is retained in any suitable manner in its seatings bl and b2 across the water-way of the tllter. the arrangement being such that liquid can pass from the inlet vpart b3 of the lter to the outlet part b5 through the filtering medium only; in Figs.
1 and 2 the ow of the water to be illtered is inwardlyv through the helical interstices between scribed except that the cake or former A' is rotatably mounted in the casing B'; the former A is provided with interior teeth a2il with which a wheel G engages; the wheel G is mounted on a spindle gl mounted in the casing A, and is adapted to be rotated by any suitable means, for example by an external handle on the spindle gl or by power, and a brushH is mounted onxa spindle hl in the casing in contact with the ltering medium, whereby when the cage A' is rotated the ltering medium is cleansed from dirt or other matter adhering to the outside.
The filtering medium formed of wires of sections shown in Figs. 4 to 11 may be employed, the shape o f the helical groove being modified as shown for example in Figs. 12 and 13.
Of the sections of wire given by way of example in Figs. 4 to 11, the wires shown in Figs, 4, 5, 7, 8
and 11 are suitable vfor those cases in which the grooves in the ribs on which the wires are' wound are adapted to take the apex or narrowest part cl of the section, as in Figs. 12, 13 and 14. e
In the cases of wires of the sections shown in Figs. 4, 5 and 8 the surface presented to the ow of liquid to be i'lltered is practically the plain cylindrical surface formed yby the-aligning faces c2 of the base ofthe section; in Figs. '7 and 11 the surfaces on each side of the entrance to the helical passage-Way` farm a reentrant angle which is found to be of advantage in some cases.
The sections shown in Figs. 6, 9 and 10are suitable for use when the grooves in the ribs' ished; similarly the wire of Fig. 10 could be wound in helical grooves of triangular crosssection' as in Fig. 12, the angle between the sides of the grooves being an obtuse angle as at c4 Fig. 12.
The bases cl (Figs. 6. 9 and 10) are in the construction last described on the entrance side to'the helical groove, the flow in this case being outwardly through the wire-wound filtering medium; the radius of curvature of the sides of the base cl of Figs. 6 and 9 is therefore made comparatively great, and the angle between the two sides of the base c4 in Flg.\10 is made very obtuse, in order to prevent any wedging action tak- 10 ing place which would tend to clog the entrance to the helical passage-ways.
The configuration of the unit is above referred to as approximately cylindrical but obviously the 4wire-wound helix isnot truly cylindrical but pol'5 lygonal, and where desired the body part al of the cage A may be made polygonal.
Having now fully described my invention, what I claim and desire to secure by Letters Patent isz- 1. In filtering apparatus in combination;a fllter casing having inlet and outlet openings; a cage located within the casing and having peripherally situated, circumferentially spaced, longitudinally disposed upstanding members constituting a polygonal former to support a filtering element comprising a wire helix wound thereon with a space between successive convolutions; jointing means on the casing and on the cage which when jointed connect the enclosed space outside the helix to one of the said casing openings and the enclosed space within the helix to the other said opening; and a filtering element consisting of a wire helix wound on said cage members with a space between its successive convolutions, the normal transverse cross-section of the wire of which the helix is wound being a segment of a circle, the helix being wound with a part oi' the circular periphery of the wire on and supported by the longitudinal members of the former, and 40 with the side of the wire Vwhich in transverse section is a straight line rdisposed in a surfaceof revolution, the generatrix of which is a line, and the axis of which is the axis of the helix, the pitch of the helix being slightly greater; than the width of the said side.
2. In filtering apparatus in combination;-a cage comprising a hollow cylindrical portion with end flanges, the outer portion of the cylinder having a series of circumferentially spaced ridges forming a series of shallow troughs bounded by the flanges and the ridges, passage-ways being provided through the flanges, one at each end of each trough; a cylindrical casing open at one end to admit the cage and having an opening through the opposite end and an opening through the side of the casing, one of said openings forming the inlet and the other the outlet for the fluid to be filtered; a seating in the said casing located between the two said openings to make joint with the inner flange of the cage when the latter is inserted in the casing; a seating at the open end of the casing to make joint with the other flange of the inserted cage; and a cover to close the open end of the casing, the inner face of said cover being some distance axially away from the adjacent flange of the cage; and a filtering medium consisting of a wire helix wound on said cage ridgeswith a space between its successive convolutions, the normal transverse cross-section of the wire of which the helix is wound being a figurev having one side which is approximately a straight line of length greater than any other transverse dimension of the figure parallelto said-line, the two sides of the figure adjacent the said straight line side converging in a direction away from the said straight line, the helix being wound with the side of the wire corresponding with the said straight line substantially forming a plain cylindrical surface. A
3. A filter constructed in accordance with claim 2, and in which the inlet for the flow of fluid to be filtered is the side opening of the casing, in which the wire forming the helix is of triangular cross-sectiony wound on the cage so that the apex is supported by the ridges of the cage and the side of the wire opposite the apex is wound to form a plain cylindrical surface intersected by a helical slot.
4. A filter constructed in accordance Awith claim 2, and in which the inlet for the flow of fluid to be filtered is at the end of the casing in which the wire forming the helix is of triangular cross-section wound on the cage so that one side of the wire is supported by the ridges, the helix having a plain cylindrical interior traversed by a helical slot.
5. A filter constructed in accordange with claim 2, in which the wire forming the filtering medium is of trapezoidal cross-section.
6. A filter constructed in accordance with claim 2, in which the wire forming the filtering medium is of semi-'circular cross-section.
FRANK O. L. CHORLTON.