This invention relates to a disposable liquid filter supported by an open mounting holder allowing simple replacement of the filter. Description of the Prior Art

Most liquid filters are installed by the user in a steel housing which is a part of the filter and of the liquid path through it. Such a prior art housing typically has inlet and outlet pipe connections and is itself a pres¬ sure vessel with a heavy cover clamped in place to make the unit leak proof and to safely contain the liquid pressure. For some applications, for example, where the liquid pres- sure does not exceed 75 psi, it may be more convenient and less expensive to have a disposable filter unit in- its own plastic housing adapted for direct hose connection ^' s at inlet and outlet.

The prior art includes U.S. Patents 3,529,726 to Keenan; 3,820,661 to Pages; and 4,505,816 to Wozniak et al. Keenan discloses a filter assembly including a tie rod mounting holder and filter unit, the filter unit being removable from the holder by loosening the tie rods. Pages discloses a filter assembly, also held together by tie rods, and including a filter element having a plurality of axial fluid channels. These channels in Pages are open at both ends for a continuous fluid flow in series from one to another. Wozniak et al. discloses a filter assembly having radial flow channels in one of its end caps. While these items of prior art variously relate to some of the elements ■ of this invention, i.e., tie rods, removable and replace¬ able filter unit, and radial flow end caps, they do not relate to the combination or the principle of operation of this invention. SUMMARY OF THE INVENTION

The present invention may be summarized as a liquid filter apparatus, for connection to inlet and outlet liquid lines, and including a mounting holder and a

removable disposable filter unit mounted in the holder. The disposable filter unit includes bottom and top end caps, with a core tube plugged at both ends and a concen¬ tric outer tube sealed to and extending between the end caps. The top and bottom end caps and the outer tube are made of a plastic material for economy and disposability. A filter element between the core tube and the outer tube stands on radial ribs extending upward from the bottom end cap and is spaced from the top end cap by similar radial ribs extending downward from the top end cap, these ribs . creating radial flow channels above and below the filter element. The filter element is a wound spiral of a sandwich including a flat filter sheet material and a corrugated impermeable polymeric separator sheet, forming a plurality of axial flow channels. Some of these axial flow channels are open at the top to receive liquid from the top radial flow channel and closed at the bottom, and some of the axial flow channels are closed at the top and open at the bottom to discharge liquid into the bottom radial flow channel. Filter action is by radial flow, through the filter material, from the open-top ^' channels to the open- bottom channels. The mounting holder includes upper and lower mounting plates and tie rods between them to releas- ably hold the filter unit together and to permit easy removal and replacement of the filter unit. The mounting plates and tie rods give strength to the filter unit., preventing liquid pressure from blowing off the end caps. Means are provided to verit _y air from the filter unit. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a sectional elevation view of the filter and mounting holder of this invention.

Figure 2 is a top vie of the upper mounting holder of FIG. 1.

Figure 3 is a partial front view of the mounting holder of FIG. 2.

Figure 4 is a schematic top view, somewhat ^' enlarged, of a filter element according to this invention.

Figure 5 is a still further enlarged schematic detail of FIG. 4.

Figure 6 is a bottom view of the top end cap. Figure 7 is a top view of the bottom end cap. DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawing, the mounting holder and filter of this invention are shown in combination, the mounting holder being generally indicated at 2 and the filter unit at 20. Mounting holder 2 includes an upper mounting plate 4 fastened to a stationary support means such as flanged brackets exemplified at 6, and a similar lower mounting plate 8 which hangs from upper plate 4 on four tie rods 10. Tie rods 10 include wing nuts 12 at their tops by which the assembly is tightened for normal operation and loosened for removal and replacement of the filter 20. Each of the mounting plates is somewhat "C" shaped, having an open aperture 14 facing forward of the apparatus (see also FIG. 2) . A pair of upper channel beam ^' s or cross bars 16 extend across the top of upper plate 4, ^' one extending -between the two tie rods 10 at the rear and one extending between the two tie rods 10 at the front. ^" Similarly, a pair of lower channel beams or cross bars 18 extend across the bottom of lower plate 8, one extending between the two tie rods 10 at the rear and one extending between the two tie rods 10 at the front. Cross bars 16 and 18 bear on their respective upper and lower mounting plates by means of the tie rods 10 and wing nuts 12 pro¬ viding longitudinal strength to the mounting plates. Cross bars 16 and 18 in the front of the unit are mounted for rotation on one of the front tie rods so they can be swung open when the wing nuts are loosened to permit placement and removal of the filter 20. The upper front cross bar 16 includes depending heel piece 17 to fill the space of the open aperture 14 when the mounting holder is closed. A similar heel piece, not shown, is mounted atop the lower front cross bar 18 for the same purpose. This makes the mounting plate-heel combination flush at top and bottom. Thus, when the filter is in place and the mounting holder

is clamped over it, the end surfaces of the top and bottom end caps are substantially in total contact with the flush mounting plate-heel combination at top and bottom. This prevents distortion of the filter and the consequent breaking of seals when hydraulic pressure is applied.

The filter 20 is an integral unit which fits into the mounting holder 2 and is laterally removable from it. Filter 20 includes a bottom end cap 22 (see also FIG. 7) having a central outlet port ^ιr 0UT" which is adapted, as for example by pipe threads, for connection to an outlet liquid line. A similar top end cap 26 (see also FIG. 6) includes a central inlet port ^•■ IN" which is also adapted, as for example by pipe threads, for connection to an inlet liquid line. Bottom end cap 22 includes a plurality of upstanding radial ribs 23 creating a plurality of radial outlet flow channels 24 ^" and supporting the filter element 40. Top end cap 26 includes a plurality of depending radial ribs 27 creating a plurality of radial inlet flow channels 28 over the filter element 40. An outer cylindrical tube 30 fits * within peripheral flange 32 in the bottom end cap 22 and peripheral flange 34 in the top end cap 26. These connections between outer tube 30 and the bottom and top end caps 22 and 26 are sealed with a sealant such as an electro-magnetically actuated polypropylene adhesive sealer or similar suitable sealing composition so that the filter unit is liquid-tight. The end caps and the outer tube are all of a plastic material such as polypropylene for economy and disposability. A normally closed vent passage 29 is provided in the top end cap 26 to remove air or gases from the system as necessary. The sealing engagement of the bottom end cap 22 with the outer tube 30, and the sealing engagement of the top end cap 26 with the outer tube 30, are all represented by deposits 50 of sealant at the respective locations of connection.

A filter element 40 (see also FIG. 4) is a spiral wound roll of a sandwich including a flat filter sheet material 43, interleaved with a corrugated polymeric separator sheet 41 resting on the tops of upstanding*ribs

23 of the bottom end cap. The corrugations of the filter element provide spacing between successive layers of the wound roll, which spaces are axial flow channels for the liquid passing through the filter. Alternate axial flow channels 42 are blanked off at the bottom, while successive alternate axial flow channels 44 are blanked off at the top so that fluid enters at the top of the open-top channels 42 and leaves at the bottom of the open-bottom channels 44. Filter action is by way of radial flow, through the filter material 43, from the open-top channels 42 to the open- bottom channels 44 as indicated in FIG. 5. The filter element 40 is formed around a core tube 46 which is sealed at its ends by plugs 48. This gives structural support to the filter element and prevents straight axial flow through its center from inlet to outlet. The blanking of the ends of the flow channels is formed by a hot melt plastic.

When a filter unit is to be changed, the-fluid system is shut down and disconnected at the inlet and outlet connections. Then the mounting holder 2.is opened by loosening the wing nuts and tie rods and the front cross bars are swung out* of the way. The filter unit 20 is then simply pulled forward out of the holder. A replacement filter unit 20 is then inserted, clamped in place, and connected to the liquid inlet and outlet lines.