Patent Publication Number: US-2010122955-A1

Title: Method and system of filtering oil

Description:
BACKGROUND OF THE INVENTION 
     This invention is directed to a method and system for filtering oil and petroleum products and more particularly for removing particles down to about 0.1 microns. 
     Methods and systems for filtering oil and petroleum products are known in the art. While these systems work for their intended purpose, these systems are not effective in removing small particles for filtrate recovery. Part of the reason is that the oil does not have an acceptable viscosity to permit the removal of small particles. Thus, a need exists in the art for a method and system that addresses these deficiencies. 
     An object of the present invention is to provide a filtering system that removes particles down to about 0.1 microns. 
     Another object of the present invention is to provide a system that utilizes a sintered module. 
     A still further objective of the present invention is to provide a system that optimizes the viscosity of the filtered material. 
     These and other objectives will be apparent to one of skill in the art based upon the following disclosure. 
     SUMMARY OF THE INVENTION 
     A filtering system having a feed tank and output line where the pressure of fluid is sensed within the line and the flow rate adjusted to maintain a selected pressure. The output line extends from the feed tank to a cell. The cell has a pump, flow meter, heater, and sintered or ceramic module. The module is connected to a filtrate tank via a filtrate line and permits fluid having particles of 0.1 microns to seep through to the filtrate line. Fluid having particles greater than 0.1 microns are released from the cell to a feed stock tank. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic of the oil filtering system; and 
         FIG. 2  is a flow diagram of a method for filtering oil. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the Figures, the system  10  has a feed tank  12 . The feed tank  12  contains used oil or petroleum. The feed tank is connected to an output line  14  that extends from the feed tank  12  to a cell  16 , or plurality of cells. Operatively connected to the output line  14  is a flow control valve  18 , an in-line filter  20 , and a pressure sensor  22 . Preferably, the in-line filter  20  is a rudimentary 5 micron in-line filter. The flow control valve  18  and the pressure sensor  22  are connected to a controller such that the controller  24  sends a signal to open or close the flow valve  18  based on a signal received from the pressure sensor  22 . In this manner, a constant pressure in the output line  14  may be preselected and maintained by the controller  24 . 
     Along the output line  14 , and downstream from the pressure sensor  22 , are a plurality of shut off valves  26 . The shut off valves are normally in a closed position, and are opened to clean or discharge fluid from output line  14 . When the shut off valve  26  is closed, flow is diverted from the output line to a cell input line  28 . 
     The cell  16 , has a shut off valve  30  that is normally opened except for cleaning or discharge, a pump  32 , a flow meter  34 , a heater  36 , a module  38 , and a flow control valve  40 . Fluid flows from output line  14  to the pump  32 , through the flow meter  34  and the heater  36 , to the sintered module  38 . Preferably, the sintered module has porous metal filter elements constructed of sintered titanium powder that has exceptional chemical and temperature resistance and can withstand repeated cycles such as the TPM Series Liquid Process Filters manufactured by Graver Technologies. The sintered module  38  is preferably porous at 0.1 micron to permit particles such as dirt, carbon, metallic fibers and the like to seep through to a filtrate line  42 . Alternatively, the module is made of a ceramic material. 
     The fluid, with particles greater than 0.1 microns, flows to flow control valve  40 . The flow meter  34  and flow control valve  40  are connected to the controller  24  such that the flow control valve  40  is opened and closed by the controller  24 , based on a signal from the flow meter  34 . When closed, or partially closed, the flow control valve  40  diverts all or some fluid back to pump  32  where the fluid is recirculated through the cell  16 . To the extent that flow control valve  40  is open, or partially open, some or all fluid flows back to output line  14  downstream from shut off valve  26 . From cell  16 , fluid flows either to subsequent cells, where the process is repeated, to a feed stock tank  44 , or back to feed tank  12 . 
     The filtrate line  42  extends from module  38  to a filtrate recovery tank  46 . The filtrate line has a flow sensor  48  that is connected to the controller  24 . A shut off valve  50  is also connected to the filtrate line  42  and is normally open except for cleaning and discharge. 
     To optimize the filtering, the fluid should have a desirable viscosity. The viscosity of the fluid is dependent upon the rate of flow, the pressure, and the temperature of the fluid. Preferably, the pressure in lines  14 ,  28  and  42  should range between 28 to 40 PSI. The temperature of the fluid should range between 340 to 360 degrees F. without exceeding 360° F. The rate of flow should range between 1.5 to 3.2 lbs/hr per sq. ft. Optimally the flow rate should be between 1.8 and 2.3 lbs/hr per sq. ft. 
     In operation, the pressure, flow rate, and desired temperature are selected and input into the system. Once inputted, the system is activated such that fluid flows from feed tank  12  to cell  16 . The pressure in line  14  is maintained at the selected rate based on a signal from pressure sensor  22  which controls flow valve  18  via controller  24 . Within the cell, fluid having particles 0.1 microns or smaller are removed through the sintered module  38  to a filtrate tank  46  through a filtrate line  42 . Fluid having particles greater than 0.1 microns recirculates within cell  16  until the fluid is released by flow valve  40  based on the rate of flow determined by the flow meter  34 . Once released, fluid flows to other cells for subsequent filtering, to a stock feed tank  44 , or back to feed tank  12 . 
     Thus a method and system of filtering oil has been disclosed that at the very least meets all of the stated objectives.