GB668705A - Filter cartridge - Google Patents

Abstract

668,705. Filters. FRAM CORPORATION. May 24, 1950. No. 13030/50. Class 46. [Also in Group XXVIII] A filter element comprises a pair of spirally coiled webs of filtering material spaced from each other by an impervious strip at one end of the coil to provide a first spiral space, the convolutions of the pair of webs being in turn spaced by a second impervious strip at the other end of the coil to provide a second spiral space. In addition a corrugated sheet of material occupies most of the remainder of the first spiral space and a narrow corrugated strip is provided in the open end of the second spiral space. A pair of webs 32, 33, Fig. 2, e.g. of treated paper is spirally coiled about an imperforate tubular core 31, the space 62 between the pair being almost filled in an axial direction by a sheet 34 of corrugated aluminium. The remainder of this space is occupied by an impervious sealing strip 35 of soft paper or cardboard which is secured in place by friction or glueing. The 'space 61 between the inner web 33 of one convolution and the outer web 32 of the previous convolution is occupied at the top by a narrow strip 36 of corrugated aluminium, and at the bottom by a narrow strip 40 similar to 35. The spacing members are omitted from the outermost convolution of the completed element to ensure that it fits snugly in a shell 42, Fig. 1. The upper end of the core tube 31 is bent over the inner edge of a cap 50 having an annular series of holes 51, while the lower end of the element is spaced from a lower cap 43 by a plate 44 having upstanding radial fins 45. The unit thus formed is held between gaskets 55 and 56<SP>1</SP> in a casing 11. Liquid to be filtered enters at 24,. passes through holes 51 into a region 53 and thence into the spiral space 61, filters. through web 32 and 33 into the spiral space 62, and collects in a chamber 56. This chamber is in communication with the inside of the core tube 31, which in turn surrounds an outlet tube 13, into which filtered liquid flows when it reaches the level of an outlet aperture 15.