Abstract:
A system for fryer oil usage has at least one fryer having a vat and a valved drain, a first oil storage container having an oil delivery line connected with the vat, a second oil storage container connected with the valved drain and vat of the fryer, both containers having an inert gas blanket in a vapor space thereof, a first filter connected with the valve of the drain of the fryer, a pump connected with the first filter and the second oil storage container and in valved communication with the vat, a polishing line connected with the pump and with the first filter, and a three-way valve movable to a first position for blocking the flow of oil, a second position for allowing the flow of oil to the second oil storage container, and a third position for allowing the flow of oil to the vat of the fryer.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority from U.S. Provisional Application Ser. No. 60/961,954, filed on Jul. 25, 2007, and entitled “Fryer Oil Supply, Recovery and Filtration System”. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
     Not applicable. 
     INCORPORATION-BY-REFERENCE OF MATERIALS SUBMITTED ON A COMPACT DISC 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to deep oil fryers used for food preparation. More particularly, the present invention relates to the storage of fryer oil, both new and used. More particularly, the present invention relates to filtration of fryer oil. More particularly still, the present invention relates to the use of recycled oil in deep oil fryers. 
     2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98 
     Restaurant fryer oils have largely consisted of hydrogenized oil in the past because they are more stable and less prone to spoilage; however, these hydrogenized oils are made of transfats which are unhealthy. Healthier, non-hydrogenized oils have become more popular and are even required for restaurants in certain areas of this country. However, non-hydrogenized oils and those high in polyunsaturated fats have a shorter shelf life than unhealthy hydrogenized trans fat oils because they are more susceptible to oxidation in addition to spoilage due to heat and light exposure. 
     Non-hydrogenized oils are susceptible because most cooking oils contain natural antioxidants. As cooking oils are exposed to oxygen, including during storage, filtration, and cooking, they slowly become rancid over time causing an unpleasant aroma and acrid taste. This oxidation also diminishes the nutrient value of vitamins, mineral, and essential amino acids in the oil. When food is dipped in and out of the hot fryer oil during cooking, the surface of the cooking oil changes over, causing depletion of the natural antioxidants even more rapidly. 
     Traditional methods of storing unused oil in restaurants, including storage in large plastic bottles and refillable interior tanks, have several problems. For example, smaller plastic oil jugs and cardboard boxes cause excessive waste disposal in the restaurant, require manpower to refill the fryers, and create an unsafe work environment due to heavy lifting, oil spillage, and sanitation concerns. When oil is poured into the fryers from traditional plastic oil jugs, the air space above the remaining oil in the jugs contains a larger volume of air than before, leaving more oxygen in the container to degrade the oil. This causes oxidation and introduces airborne contaminates that degrade the stored oil. 
     Larger refillable interior containers are occasionally used by restaurants; however, they also expose the oil to airborne contaminates and air (causing oxidation), reducing freshness and leading to unpleasant aromas and flavors. These containers are also held at atmospheric pressure, exposing the oil to humidity and environmental contaminates. 
     Traditionally, waste fryer oil is disposed of and stored by transferring it from a fryer to a pit, trap, sump, or container. The waste oil in these containers is sometimes used to make biodiesel. Biodiesel is made by chemically reacting vegetable oil with alcohol and a catalyst in a process called transesterification. This chemical reaction breaks down the fat molecules in the oil into an ester, which is the biodiesel fuel and glycerol. Many makers of biodiesel tend to avoid rancid oils because rancid oil produces less biodiesel and may not even react to make it. In addition, airborne contaminates and rancidity affect the value of the oil as a recyclable product. 
     Waste fryer oil should be turned into biodiesel as soon as possible or stored in a proper environment to make it more usable as a fuel. Waste oil already contains free fatty acids caused by cooking. As the waste oil oxidizes and becomes more rancid with air contact, the amount of free fatty acids increases. Vegetable oil, which has less free fatty acids, requires less chemical treatment to convert it to usable diesel fuel, and results in a greater percentage of the oil converting to usable biodiesel. 
     There are several waste oil storage containers on the market for indoor storage of waste oil; however, none of these containers store the waste oil in a manner that optimizes its recycled use for biodiesel, consumer products, animal food, or other various uses. Most containers store oil at atmospheric pressure and with air in the vapor space. As discussed above for unused oil storage containers, this method of storage subjects waste oil to oxidation, humidity and accelerated deterioration. 
     Waste oil discharge to an outdoor sump or grease trap is subjected to weathering, moisture, oxidation, debris and environmental contamination. The grease trap or sump is perhaps the worst storage method because it dramatically reduces the possibility of recycling the waste oils into usable product because the waste fryer oil is depleted of antioxidants and is subject to rapid deterioration due to oxidation. In this type of storage, waste oil can become rancid very quickly. Exposure to air, humidity, and environmental contaminates only hastens the rancidity of the waste oil. It also makes the oil more expensive to recycle and reduces its worth. Oils from restaurant grease traps can contain residues from pesticides, cleaning agents, debris, and any number of other contaminates. Removing these contaminants along with any moisture requires additional refining during filtration, which takes more time and increases the cost of recycling. 
     Some waste oil storage containers exist on the market for recycling the waste fryer oil in the fryers. Some are even designed for outdoor storage, however, all of them are subject to atmospheric conditions and allow oxidation of the waste oil. This not only leads to the rancid oil smell during storage, but causes the oil to deteriorate, reducing its recycled worth. 
     Traditionally, waste oil in a deep fryer system is filtered in order to increase its useful life. Unfortunately, the most efficient and quickest filtration systems require a very low-viscosity oil. High temperature oils, in the typical fryer temperature range of 350-400° F., have low viscosity and are more easily filtered than cooler oil. Filtering heated oil allows the hot oil to be returned to the fryers, reducing energy usage otherwise needed for reheating oil. Therefore, filtering hot fryer oil is more energy efficient and easier to filter than cooled oil. 
     Typically, a fast food restaurant will filter the oil in each vat of the fryer once or twice per day. The typical deep fryer system in a restaurant will include a plurality of fryer vats. Most existing oil filtration systems, whether portable or stationary, require oil to gravity-drain from the fryer into a filter housing. The oil flows through a filter mesh, cloth or steel, and then is pumped back into the fryer vat. Sometimes the restaurant will flush the oil through the vat for several minutes, allowing it to flow from the fryer vat into the filtering housing and back through the filter several times in a process called “polishing” the oil. 
     Filtering hot oil causes several safety concerns, primarily for burns. The United States Occupational Safety and Health Administration recommends against handling hot oil. However, most restaurants that use deep fryers typically ignore these recommendations. Hot oil is handled because it takes longer to filter the oil when it cools, the quality of the filtered oil is less when it is filtered cold as opposed to when it is filtered hot, and the time it takes for the oil to cool decreases productivity and wastes energy that is needed to reheat the cooled oil. 
     Typical filtration systems are designed for indoor use in the kitchen area of a restaurant. The systems are usually not sealed and sometimes require moving containers of hot oil around the kitchen of the restaurant where oil spills create slipping hazards. The oil containers where the oil is stored are open to the atmosphere. Likewise, the filter systems are open to the atmosphere, which allows the odor of the old oil to discharge into the restaurant. These indoors system are not designed to be used away from the kitchen in an outdoor environment so as to remove the “old oil” smell from the kitchen. Oil is usually stored in containers that are indoors and have the “old oil” smell. 
     It is desirable to keep unused oil as fresh as possible during storage so as to preserve the useful life of unused oil. It is similarly desirable to keep waste fryer oil as fresh as possible during storage and filtering so as to maximize the value of waste oil as a recyclable material. This is best accomplished in a reduced oxygen environment, preferably in the absence of oxygen and other airborne contaminants. Waste fryer oil is also preserved by minimizing its exposure to moisture and humidity and other airborne contamination during storage. 
     Various patents have issued and applications published relating to the filtering and storage of fryer oil. For example, U.S. Pat. No. 5,228,985, issued to Wells et al., describes a portable cooking oil filtering unit that has an outer housing completely enclosing all the filter stages and providing access to the stages for maintenance purposes via doors and removable closures. The housing has an inlet conduit for connection to a cooking vat drain outlet, and an outlet conduit for returning filtered oil to the cooking vat. A first stage filter in the housing is connected to the inlet conduit for filtering relatively large size particles from the oil, and the filtered oil is connected to at least one additional filter stage for filtering smaller particles from the oil. A pump is connected downstream of the final filter stage, between that filter stage and the outlet conduit, for drawing oil through the filter stages under vacuum rather than pumping it through the filters under positive pressure. One of the filter stages is accessible to allow oil-life enhancing chemicals to be added to the oil. 
     U.S. Pat. No. 4,913,922, issued to Hawkes et al., describes a method and apparatus arrangement for continuous cooking of food in hot oil with clarification, purification and recycle of oil. Particulates-laden oil from the cooker is passed through a comminutor then through a precoat filter to remove particulates. The filter bed may also contain a quantity of an adsorbent to remove free fatty acid from the oil before reuse. Elevated temperatures are maintained and the operation is conducted in an oxygen-poor environment. An apparatus arrangement includes a cooker, a comminutor and an enclosed precoat filter through which all oil passes. Appropriate piping and controls are provided. 
     U.S. Pat. No. 4,646,793, issued to Sherratt, describes a cooking oil and grease recycling apparatus for collecting hot cooking oil from fryer vats in restaurants and industrial food preparation companies and replacing it with fresh oil or grease. Holding tanks are connected to the frying vats by piping, which includes valves and pumps to permit the used oil or grease from the frying vats to flow into a holding tank. The holding tanks are in a location accessible for trucks to connect a hose for pumping the used liquid oil or grease into the truck tank. A second hose is connected from the truck tank to pump new, fresh oil or grease into a distribution tank which are mounted above the frying vats at any convenient place in the restaurant. The invention also includes a portable system preferably including a pump to distribute oil to the frying vat and a holding tank. 
     U.S. Pat. No. 6,783,685, issued to Hwang, describes an invention that is directed to an oil treatment apparatus and method for treatment of oil which transports oil to be treated from a source through a first conduit to a treatment station. The treatment station includes a filter system capable of extracting particulate material from the oil and removing the particulate material from the filter system as it is removed from the oil. The treated oil may then be transported for reuse, preferably in a continuous cycle with the source of the oil. A prefiltering system may be used to further enhance maintaining the quality of the oil and/or in efficiently treating the oil while accommodating throughput requirements. The prefiltering system may include a comminuter to reduce the size of larger particles in the oil, a coarse filtering system to remove larger particles, and a system to introduce a treatment material to the oil or other systems to facilitate processing. The filtering system is designed to remove particles from the oil having a size of fifteen microns or smaller in the preferred embodiment. 
     U.S. Patent Publication No. 2002/0174778, issued to Petrusha, describes a system for removing cooking oil from a fryer vat that includes a storage tank for storing cooking oil. The storage tank is disposed remotely from the fryer vat and in fluid communication with the fryer vat through a fixed piping system. A pump is arranged to transfer cooking oil from the fryer vat to the storage tank through the fixed piping system. A shut-off valve for directing cooking oil transferred by the pump to the storage tank is also provided. The shut-off valve is movable between an open position wherein the shut-off valve permits cooking oil to flow through the fixed piping system to the storage tank and a closed position wherein the shut-off valve blocks flow of cooking oil through the fixed piping system to the storage tank. A level sensor is arranged to detect whether the cooking oil in the storage tank is at a predetermined level. When the level sensor detects that the cooking oil in the storage tank is at the predetermined level, the shut-off valve moves from the open position to the closed position or the pump stops transferring cooking oil to the storage tank. An alarm device can provide an audio or visual alarm signal when the level sensor detects that the cooking oil is at the predetermined level. 
     U.S. Pat. No. 6,202,543, issued to Moya et al., describes a system for use with a hot oil fryer of the type which cooks food products in hot oil. Particulates from the food are shed into the hot oil in the fry during the cooking operation. The fryer has an inlet to receive hot oil, and an outlet for recirculation of hot oil. 
     U.S. Pat. No. 5,964,258, issued to Schoenbauer et al., describes a bulk cooking oil supply and disposal transport system and method for the supply of cooking oil to and the removal of waste oil from a receiving facility. The system includes a transport vehicle with a supply and a waste oil container. An oil conduit system is connected with the supply and waste container to selectively deliver and remove oil through oil fittings. Pumps and valves are disposed within the oil conduit system for restricting the flow of the cooking oil therethrough. A first fluid meter measures the amount of cooking oil delivered to the receiving facility and a second fluid meter measures the amount of waste oil removed from the receiving facility. A control device receives signals indicating the level or amount of oil delivered or removed through the oil conduit system. Signals are generated by sensors at the receiving facility or from the fluid meters monitoring flow through the system. A data reporting device is provided on the vehicle to document the amount of cooking oil delivered to and the amount of waste oil received from the receiving facility. 
     It is an object of the present invention to provide a sanitary, oxygen-free storage environment for new fryer oil storage. 
     It is another object of the present invention to provide an environment for new fryer oil storage that reduces contamination and retains freshness and flavor of the oil during storage in either an indoor or an outdoor environment. 
     It is still another object of the present invention to provide a sanitary, oxygen-free storage environment for waste oil storage. 
     It is another object of the present invention to provide an environment for waste oil storage that reduces contamination and retains freshness and flavor of the oil in either an indoor or an outdoor environment. 
     It is another object of the present invention to provide a filtration system that filters hot oil. 
     It is another object of the present invention to provide a filtering system that minimizes fryer oil exposure to the environment. 
     It is still another object of the present invention to provide a filtering system that eliminates the need for handling hot waste oil. 
     It is yet another object of the present invention to provide a filtering system that allows the user to choose to continuously filter waste oil or send waste oil to a waste oil storage container or recycle waste oil back to the fryer. 
     It is yet another object of the present invention to provide a fryer oil usage system that is weather-resistant. 
     It is yet another object of the present invention to provide a fryer oil supply and recycling system that is located outside of the restaurant so as to minimize the rancid order of used oil inside the restaurant. 
     These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is a system for fryer oil usage comprising at least one fryer having a vat and a drain having a valve means for opening and closing the drain, a first oil storage container having an oil delivery line in fluid communication with the vat of the fryer and an inert gas blanket in a vapor space of the first oil storage container, and a second oil storage container having an inert gas blanket in a vapor space of the second oil storage container and being in fluid communication with the valve means of the drain of the fryer and being in valved communication with the vat of the fryer. The first oil storage container is a container of stainless steel or other material maintaining a positive pressure and temperature rating of up to 400° F. The second oil storage container is a container of stainless steel or other material maintaining a positive pressure and temperature rating of up to 400° F. 
     The fryer oil usage system further comprises an inert gas supplying means for maintaining a constant pressure in the vapor space of the first oil storage container and in the vapor space of the second oil storage container and being in valved communication with the first and second oil storage containers, a first filtering means for filtering oil from the fryer in fluid communication with the valve means of the drain of the fryer, a pumping means for filtering the oil passing from the fryer in fluid communication with the first filtering means and the second oil storage container and in valved communication with the vat of the fryer and the pumping means for vacuuming oil from the fryer through the first filtering means, a polishing means for recycling oil through the first filtering means in fluid communication with the pumping means and with the first filtering means, a selecting means for selecting the direction of a flow of oil being movable to a first position for blocking the flow of oil, a second position for allowing the flow of oil to the second oil storage container, and a third position for allowing the flow to the vat of the fryer and being in fluid communication with the pumping means and with the polishing means and with the second oil storage container, and a second filtering means for filtering oil passing from the fryer being in fluid communication with the selecting means and in valved communication with the fryer. 
     The first filtering means comprises a housing able to withstand 400° F. and able to operate under positive internal pressure or a vacuum. The housing has a body and lid or hatch opening, allowing access for changing the filter. The housing can be rectangular, cylindrical or another shape. A filtration media suitable for removing solids from the oil of the fryer is located inside the housing and removable through the lid or hatch opening. A seal is located between the body and the lid of the housing and has the ability to withstand 400° F. and has the ability to operate in a vacuum on positive internal pressure. 
     An alternative second filtering means comprises a housing having a removable cover or hinged cover. The housing is in fluid communication with the selecting means and in valved communication with the vat of the fryer. A filtration media is removable from the housing through the cover or hatch opening. The filtration media is suitable for removing particulate matter that is smaller than the solids removed by the first filtering means. 
     The first filtering means, the second filtering means, the pumping means, second oil storage container, the first oil storage container, the inert gas supplying means, the polishing means, and the selecting means are all positioned in spaced relation to the fryer. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a plan view of the fryer oil usage system of the present invention. 
         FIG. 2  is a perspective view of the oil storage containers of the present invention. 
         FIG. 3  is a first alternative embodiment of the fryer oil usage system of the present invention. 
         FIG. 4  is a second alternative embodiment of the fryer oil usage system of the present invention. 
         FIG. 5  shows a perspective view of the primary hot oil filter of the first filtering means of the first alternative embodiment as shown in  FIG. 3 . 
         FIG. 6  is a perspective view of the second filtering means of the second alternative embodiment as shown in  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , there is shown the fryer oil usage system  100  in accordance with preferred embodiment of the present invention. The fryer oil usage system  100  includes fryers  75  that have vats  1  and drains  2 . As can be seen, the valve means are two-way valves  3  connected to the drains  2  of the fryers  75 . The valves  3  have a line  4  through which the oil from the fryers  75  flows through to the first filtering means  76 . Line  4  has a backflow prevention device  5  so as to prevent oil from flowing from the first filtering means  76  back to the fryers  75 . The first filtering means has a housing  7 , a lid  6 , a seal  8  and a filtration media  9 . The filtration media  9  is kept within housing  7  by closing the lid against the seal  8  of the housing  7 . The seal  8  acts to give the housing a gas-tight seal. Oil flowing from line  4  into the filter housing  7  is passed through filtration media  9  to the drain of the filter  10  where it passes in line  11  to the pump  12 . The pump  12  causes oil to flow from the vats  1  of the fryers  75  through the drains  2 , the valves  3 , and line  4  and through the first filtering means  76  to the pump  12  by means of a vacuum pressure. The housing  7  of the first filtering means  76  has an air relief line  18  in the event air builds up in the housing  7 . The air relief line  18  has a backflow prevention device  19  so as to prevent air from going into the housing  7  of the first filtering means  76 . A pressure relief valve  17  is also attached to the housing  7 . 
     Once oil passes through line  11  to the pump  12 , it is sent to the selecting means  24  where it can either flow by line  22  to the second oil storage container  21 , by line  25  back to the vats  1  of the fryers  75 , or through the polishing line  15  back to the first filtering means  76 . The pump  12  has a motor  13  in a weather-protective housing  65 . In the preferred embodiment, the selecting means  24  is a three-way valve. When the three-way valve  24  is positioned to block the flow of oil, oil flows through the polishing line  15  back to the first filtering means  76 . The blockage of flow of oil by the three-way valve  24  causes a rise in pressure in the outlet line of the pump  12  which opens a pressure relief valve  14  and allows flow in the polishing line  15 . There is a backflow prevention device  16  on polishing line  15  so as to prevent flow from going from the first filtering means  76  back to the pump  12 . 
     When the three-way valve  24  is positioned to allow flow to the second oil storage container  21 , oil flows from the three-way valve  24  through line  22  to the second oil storage container  21 . There is a backflow prevention device  23  on line  22 . When the three-way valve  24  is set to allow flow of oil to the fryers  75 , oil flows through line  25  to valves  26 . Valves  26  are typical two-way valves which can be opened and closed manually. When valves  26  are opened, oil flows from line  25  into the vats  1  of the fryers  75 . Oil can also flow from line  25  through valve  27  where it flows through a flexible line  28  to a hot oil sprayer  29 . 
     Still referring to  FIG. 1 , the first oil storage container  33  is connected by line  45  to the fryers  75 . An inert gas supplying means  47  is connected to the first oil storage container  33 . In the preferred embodiment, the inert gas supplying means  47  is a supply of nitrogen gas. Nitrogen is supplied from the nitrogen supply  47  so as to create a nitrogen blanket in the vapor space of the first oil storage container  33 . The pressure from the nitrogen supply  47  also forces oil through line  45  to the fryers  75 . This accomplished when valves  74  are open. Valves  74  are typical two-way valves which can be opened or closed manually. Therefore, when valves  74  are in the open position, oil flows from the first oil storage container  33  to the vats  1  of the fryers  75  because of the pressure supplied by the nitrogen blanket from the nitrogen supply  47 . The nitrogen blanket in the first oil storage container  33  helps ensure that the oxygen and other environmental contaminants are removed from the vapor space above the oil in the first oil storage container  33 . This also reduces humidity and oxidation of the oil so as to cause the oil to stay fresher longer. Alternatively, the second oil storage container  21  may be directly connected to the nitrogen supply  47 , using a separate line and regulator. Nitrogen passes from the first oil storage container  33  by line  36  to the second oil storage container  21 . Thus, the second oil storage container  21  also has a nitrogen blanket in its vapor space. The nitrogen blanket of the vapor space has the same preservative qualities for the oil in the second oil storage container  21  as does the nitrogen in the vapor space of the first oil storage container  33 . 
       FIG. 2  shows a detailed view of the first oil storage container  33 , the second oil storage container  21 , and the nitrogen supply  47 . Nitrogen travels from the nitrogen supply  47  through a nitrogen regulator  48  then through a backflow prevention device  49  to a valve  50 . Valve  50  is a typical needle valve that can be opened or closed manually. When valve  50  is opened, nitrogen flows from the nitrogen supply  47  to the first oil storage container  33 . The pressure of the nitrogen in the first oil storage container  33  is shown on pressure indicator  51 . The first oil storage container  33  has a manway access  52  for cleaning the first oil storage container  33 . As can be seen, the container  33  also has a level indicator  53  and a visual level indicator  34 . 
     The first oil storage container  33  can sit in a oil spill containment basin  43 , if required. Oil can be added to the first oil storage container  33  by inlet nozzle  44 . Pressure of nitrogen by the nitrogen supply  47  causes oil to flow through line  45 . Valve  46  is a typical two-way valve that can be opened or closed manually. When valve  46  is opened, oil travels through line  45  to the vats  1  of the fryers  75 . Nitrogen in the vapor space of the first oil storage container  33  travels through a pressure relief valve  35  to the second oil storage container  21  through line  36 . Air from filter housing  7  can also travel into the second oil storage container  21  through line  18 . The second oil storage container  21  can alternatively be directly connected to the nitrogen supply. Backflow prevention device  19  prevents any vapor from traveling from the second oil storage container  21  to the filter housing  7 . When air travels from the filtering housing  7  to the second oil storage container  21 , there may be a need to release air from the second oil storage container  21 . Air and/or nitrogen is released from the second oil storage container  21  by opening valve  32  and releasing it through air filter  37 . Valve  32  is a typical two-way valve that can be opened or closed manually. The second oil storage container  21  also has a pressure relief valve  40  for relieving nitrogen or air in the vapor space of the second oil storage container  21 . 
     The second oil storage container  21  has a manway access for cleaning the second oil storage container  21 . The second oil storage container  21  has a level indicator  39  and a visual level indicator  30 . The second oil storage container  21  can sit in an oil spill containment basin  42 , if required. 
     Oil travels from the selecting means  24  through line  22  into the second oil storage container  21 . A backflow prevention device  23  exists on line  22  so as to keep oil from traveling from the second oil storage container  21  back to the selecting means  24 . The second oil storage container  21  has a discharge fitting  41  for draining oil from the container  21 . 
     Referring to  FIG. 3 , there is shown a first alternative embodiment of the present invention. The embodiment is the same as those shown in  FIGS. 1 and 2 , except that the filtering system has a primary hot oil filter  63  and a hot oil filter  7 . Hot oil filter  7  is the same as the first filtering means  76  in  FIG. 1 . Oil flows from the drain line  4  of the fryers  75  into the filtering system. The first stage of filter is the primary hot oil filter  63  where large solids are removed. The oil then flows from the primary hot oil filter  63  through line  77  into the hot oil filter  7 . Oil is filtered, as stated above, in the hot oil filter  7  and flows through line  11  to the pump  12 . Oil flows from the pump to the selecting means  24 , which is typically a three-way valve. Oil can flow from the pump  12  through the polishing line  15 , through the recycle line  25  or through the waste oil line  22  depending on which position the selecting means  24  is placed. 
     Referring to  FIG. 4 , there is shown a second alternative embodiment of the present invention. Oil is filtered through the first filtering means  76  and travels to the pump  12  through line  11 . Oil then flows from the pump  12  to the selecting means  24 , which is a three-way valve. When the three-way valve is positioned to block the flow of oil, pressure in the oil line causes the pressure relief valve  14  to allow the flow of oil through the polishing line  15  back to the first filtering means  76 . Oil is continuously recycled, or “polished,” when the three-way valve is set to block the flow of oil. The three-way valve  24  can also be set to a second position that allows oil to flow to the second oil storage container  21  through line  22 . The three-way valve  24  can be set to a third position allowing oil to travel through line  78  to a second filtering means  64 . The second filtering means  64  removes solid particulates from the oil and gives the user an option to add preservatives to the oil. After passing through the second filtering means  64 , oil passes from line  25  to the valves  26  and then to the vats  1  of the fryers  75 . 
       FIG. 5  shows the primary hot oil filter  63  of the first alternative embodiment shown in  FIG. 3 . As can be seen, the filter  63  has a cover  66  that fits over a seal  68  and is secured the filter  63  by latch  67 . Inside the filter  63  is a filter basket  69  which removes large particulate matter. 
       FIG. 6  shows the second filtering means of the second alternative embodiment shown in  FIG. 4 . The second filtering means  64  has a cover  70  that fits over a seal  72  and is secured to the second filtering means  64  by latch  71 . Inside the second filtering means  64  is a filter basket  73  which is removable and can be of a fine mesh screen so as to remove small particles, or it can be a mesh filter basket that is used for holding additives that are added to the oil as oil passes through the second filtering means  64 . 
     The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction can be made within the scope of the appended claims without departing from the true spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents.