Patent GB-352553-A (GB)
Title: Improvements in strainers for oil or other fluids
IPC: F16N39/06
Filed: 1930-01-16
Abstract: 352,553. Filters or strainers. SHANNON, D. M., 106, Fenchurch Street, London. Jan. 16, 1930, No. 1512. [Class 46.] The invention relates to that class of filters or strainers which can be rotated in order that successive sections of the straining element may be subjected to a reverse cleansing flow of liquid. A pump is used to cause the reverse flow of strained liquid and this liquid after reverse passage through the strainer enters a trap or separating chamber, in which solid impurities are collected and from which the liquid itself passes back to the inlet side of the strainer, thus rejoining the main flow. The straining member is cylindrical and constructed of wire gauze or perforated metal, or of a spirallywound strip, or of laminae in the form of rings with one or both sides, embossed, indented, or grooved. The strainer A, Fig. 1, is built up of annular laminae provided with teeth t<1>, so that the element takes the form of a toothed wheel, which is in gear with a toothed pinion B. With the normal straining flow outward, the teeth of the pinion constitute a pump and cause a reverse inward flow through the spaces between those teeth of the element with which they are at any time engaged. This flow is directed towards the bottom of a trough E, where solid impurities collect, while the liquid passes through apertures e3 and joins the unstrained liquid within the strainer A. The grooved laminae may alternate with plain spacing laminµ, which are also formed with teeth, but these teeth may be undercut, as shown in Fig. 6, so as to give an increased straining area. Modified forms of the undercut are described. Figs. 7 and 8 show an element within a casing F with inlet I and outlet O, the normal straining flow being inward through the element. The teeth t<1> are formed on the inner edges of the laminae and the pinion B<2> is within the element and rotated by means of a handle b<3>. The element is provided with end rings a<1> to which it is secured by bolts passing through lugs on the laminae. The impurities carried down by the reverse outward flow are deposited in the trough E<2>, which is provided with depending baffles e<4>, outlets e<3> for liquid, and an outlet e<5> for the deposited impurities. An arrangement is shown diagrammatically in Fig. 9e in which the laminµ themselves are not provided with teeth, but are mounted to form the straining surface on the outside of an internally-toothed cylinder W which has apertures w<2> through which the liquid flows from each section of the straining surface. The efficiency of the pumping action may be increased by a member K, the faces of which are just cleared by the tips of the teeth on the cylinder and on the pinion B<6>. In an arrangement shown in Figs. 16 and 17, the straining- element is not provided with teeth, but a toothed wheel G on the shaft a<5> of the element and a pinion B<3> engaging therewith act as a gear pump to give a reverse flow through the portion of the straining surface opposite to a trough-like structure H which is fixed longitudinally within the element. Strained liquid is drawn through a passage f<16> to the spaces between the teeth on the wheel G and is delivered therefrom to spaces between the teeth of the pinion B<3> and thence through a passage f<15> into the part H. An arrangement in which a piston pump p<5> takes the place of the gear pump is shown in Fig. 18. The suction valve p<4> of the pump is connected to the passage f<16> and the delivery valve p<2> to the passage f<15>. The piston p<5> is operated by a lever p<6>, which carries a rachet p<8> engaging a wheel a<10> by which the straining element is rotated. The arrangement is such that the element is temporarily at rest during each delivery movement of the pump. The invention is particularly applicable in connection with the straining of oil on motor vehicles in which case the strainer and the pump may be rotated by operation of the clutch pedal. The strainer may be on the suction side of the main oil pump of the vehicle and the compartment H connected to the delivery side so as to secure a continuous reverse cleansing flow The Provisional Specification describes a flat strainer formed by winding a metal tape spirally and mounted to rotate within a casing, the strainer being cleansed by the reverse flow of strained liquid through successive sector-shaped sections as they pass between compartments separated from the main spaces on either side of the strainer.