Advanced dual filtering apparatus

A dual filtering apparatus for filtering and purifying contaminated oil used in deep-fat frying vats, comprising:

• a tub divided into an upper chamber and a lower chamber by a substantially horizontal divider;
• a remote filtering screen attached to the tub by a flexible conduit through which the oil is conveyed, the remote filtering screen being adapted for placement in the vat and providing partial filtering of oil before it is conveyed to the tub, the remote screen being comprised of a two-layer, envelope-like, perforated element positioned between two layers of an envelope filter, a first layer of the element and a first layer of the envelope filter having coaxially alignable apertures for allowing the flexible conduit to be inserted in fluid communicating relationship with the interior of the two-layer perforated element, the envelope filter being comprised of Nylon 6 having 25 micron openings therein;
• a handle on the flexible conduit for manipulating the remote screen and placing it inside the vat of oil to be filtered;
• a fine filtering assembly at least partially disposed within the upper chamber of the tub and comprising a generally cylindrical canister having a cap covering the canister on its top, the cap having an annular depending skirt that fits into the interior of the canister;
• a central conduit through a portion of the canister and in fluid communicating relationship with the lower chamber of the tub;
• a perforated lower retainer plate disposed around the central conduit and forming together with the bottom of the cannister a lower sediment area;
• a perforated upper retainer plate disposed around the central conduit and forming together with the cap an upper void area, the central conduit being in fluid communicating relationship with the upper void area;
• a tightly wound fibrous filter in surrounding relationship to the central conduit between the lower and upper plates, upward displacement of the filter being prevented by the upper plate which is held against the filter by the depending skirt of the cap, the fibrous filter being comprised of 30-50% crepe;
• an inlet conduit through the bottom of the canister through which partially filtered oil is conveyed from the flexible conduit to the lower sediment area and through the fibrous filter;
• an overflow conduit through the bottom of the canister, the overflow conduit being provided with a pressure relief valve which opens in response to an increase in pressure in the lower sediment area for dispelling overflow from the canister to the lower chamber through an overflow conduit;
• an introduction port in the inlet conduit through which oil from the flexible conduit is introduced into the inlet conduit;
• a first check valve in the inlet conduit which moves between a closed position for preventing passage of oil to the lower chamber when oil is being drawn through the flexible conduit and forced through the fibrous filter, and an open position for allowing oil to move through the inlet conduit from the lower chamber to the flexible conduit when oil is being expelled through the flexible conduit;
• a second check valve in the central conduit which moves between a closed position when oil is being expelled through the flexible conduit and an open position when oil is being forced through the fibrous filter and into the central conduit;
• a first compression sealing means secured to the upper plate in surrounding relationship to the central conduit and a second compression sealing means circumferentially secured to the upper plate adjacent the inner wall of the canister in sealing engagement therewith;
• a motor-driven pump disposed in the upper chamber for drawing fluid from the vat through the flexible conduit and forcing it into the inlet conduit when the check valve in the inlet conduit is in the closed position and the motor is rotating in a forward direction, and for drawing oil through the inlet conduit into the flexible conduit and back to the vat when the check valve in the inlet conduit is in the open position and the direction of the motor is reversed.

A dual filtering apparatus for filtering and purifying contaminated oil used in a deep-fat frying vat, comprising:

• a tub;
• an external conduit in fluid communicating relationship with the tub and through which oil is conveyed from the frying vat;
• a remote filtering screen between the vat and external conduit for providing partial filtering of the oil before it is conveyed to the tub;
• a fine filtering assembly carried by the tub and comprising a generally cylindrical canister having a cap covering the canister on its top, the cap having an annular depending skirt that fits into the interior of the canister;
• a central conduit through a portion of the canister and in fluid communicating relationship with the tub;
• a perforated, lower retainer plate disposed around the central conduit and forming together with a bottom and side walls of the canister a lower sediment area;
• a perforated upper retainer plate disposed around the central conduit forming together with the cap an upper void area, the central conduit being in fluid communicating relationship with the upper void area;
• a fine filter means mounted in surrounding relationship to the central conduit between the lower and upper plates, upward displacement of the filter means being prevented by the upper plate which is held against the fine filter means by the depending skirt of the cap;
• an inlet conduit through the bottom of the canister through which partially filtered oil is conveyed from the external conduit to the lower sediment area and through the fine filter means;
• an overflow conduit through the bottom of the canister, the conduit being provided with a pressure relief valve which opens in response to an increase of pressure in the lower sediment area;
• means for drawing oil through the external conduit and forcing it into the inlet conduit, through the fine filter means, into the central conduit and then to the tub;
• and
• means for drawing oil from the tub and expelling it through the external conduit into the vat.