Patent Abstract:
A system for removing cooking oil from a fryer vat is provided. The system 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.

Full Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS  
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/293,855, filed May 25, 2001. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention generally relates to systems for handling cooking oils and, more particularly, to an improved system for collecting waste, spent cooking oil from fryer vats.  
         BACKGROUND OF THE INVENTION  
         [0003]    Historically, a number of techniques have been used for removing waste cooking oil or grease from fryer vats in a restaurant environment. These techniques generally involve transferring the waste cooking oil which is removed from the individual fryer vats to a remote bulk storage container, such as a tank or drum, which can be arranged either inside or outside the restaurant. The waste cooking oil typically remains in the bulk storage container until it is picked-up for delivery to a rendering facility where it can be recycled for use in products such as animal feed supplements.  
           [0004]    The techniques which have been and are currently being used suffer from the drawback that they typically require restaurant employees to physically handle and move containers filled with cooking oil. For example, until recently, it was common for restaurant employees to drain the fryer vats into containers which were then hand carried to a refuse area where the waste cooking oil would be transferred by hand into a larger bulk storage container. As can be appreciated, the manual handling of the containers of cooking oil which is associated with this technique creates a significant risk of splashing and spilling of the cooking oil. If the cooking oil is still at an elevated temperature, this splashing and spilling could result in the employee handling the cooking oil being burned. Moreover, spilled cooking oil can be quite slippery which creates a hazard for other employees as well. The splashing and spilling of the cooking oil also could pose health hazards particularly if it occurs in an area of the restaurant where food is prepared.  
           [0005]    One commonly used technique which has been developed to reduce the amount of manual handling of the cooking oil involves the use of wheeled caddies which can fit underneath the fryers and receive the spent cooking oil upon the opening of a drain valve in the fryer. Once the spent cooking oil is drained from the fryer vat, the caddie is wheeled to a remote tank to which the spent cooking oil is then transferred. While this system reduces the risk of spills when handling the waste cooking oil, this technique is quite labor intensive and time consuming. The storage of the wheeled caddies can also consume valuable floor space.  
         SUMMARY OF THE INVENTION  
         [0006]    A system for removing cooking oil from a fryer vat is provided. The system 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.  
           [0007]    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.  
           [0008]    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.  
           [0009]    These and other features and advantages of the invention will be more readily apparent upon reading the following description of a preferred exemplary embodiment of the invention and upon reference to the accompanying drawings wherein: 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is a schematic perspective view of an illustrative waste cooking oil handling system constructed in accordance with the present invention which provides for automated removal of waste cooking oil to a load-out tank.  
         [0011]    [0011]FIG. 2 is a schematic plan view of the waste cooking oil handling system of FIG. 1.  
         [0012]    [0012]FIG. 3 is a schematic side elevation view of the waste cooking oil handling system of FIG. 1.  
         [0013]    [0013]FIG. 4 is an enlarged schematic side elevation view of the waste cooking oil handling system of FIG. 1 showing the connection to the load-out tank.  
         [0014]    [0014]FIG. 5 is partially exploded perspective view of an exemplary load-out tank for use in the waste cooking oil handling system of FIG. 1.  
         [0015]    [0015]FIG. 6 is a schematic drawing of an exemplary controller for use in the waste cooking oil handling system of FIG. 1.  
         [0016]    [0016]FIG. 7 is a schematic drawing of a further embodiment of a waste cooking oil handling system according to the present invention. 
     
    
       [0017]    While the invention will be described and disclosed in connection with certain preferred embodiments and procedures, it is not intended to limit the invention to those specific embodiments. Rather it is intended to cover all such alternative embodiments and modifications as fall within the spirit and scope of the invention.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    Referring now more particularly to FIG. 1, there is shown a schematic block diagram of an illustrative waste cooking oil handling system constructed in accordance with the present invention for automatically removing spent cooking oil from one or more fryer vats. The present invention substantially eliminates the need for manual handling of waste cooking oil. Thus, messy and dangerous cooking oil spills are substantially eliminated. Moreover, the present invention makes the cooking oil changing process much less labor intensive and time-consuming than the commonly used manual techniques.  
         [0019]    While the present invention is described in connection with the removal of cooking oil from a plurality of fryer vats, those skilled in the art will appreciate that the distribution system of the present invention could be used in conjunction with a single vat. Moreover, while the invention is described in the context of a restaurant environment, it will be readily appreciated that the present invention is equally applicable to the removal of other materials such as grease from other types of cooking equipment such as may be used in food preparation plants. Thus, as used herein, the term cooking oil refers to any fluid such as cooking oil, grease, shortening and the like which are used to cook food. Moreover, the term fryer vat is used to refer to any cooking equipment that uses such a fluid.  
         [0020]    For storing the spent cooking oil, the illustrated handling system includes a waste oil bulk load-out tank  14  as shown in FIGS.  1 - 3 . The load-out tank  14  preferably has a capacity several times the capacity of the fryer vat, such as for example 100-250 gallons. The load-out tank  14  can have a conventional design and can be located either inside or, as in this case, outside the restaurant. If the load-out tank  14  is arranged inside the restaurant, it is preferred that hook-ups be provided on an outside wall of the restaurant so that the tank can be easily drained via a pumper truck on the outside of the building. An example of a suitable load-out tank that can be located outside the restaurant is the Model ME480E OUTDOOR RECYCLER sold by Mahoney Environmental of Joliet Illinois. An example of a suitable load-out tank that can be located inside the restaurant is the Model ME 1103 INDOOR RECYCLER sold by Mahoney Environmental.  
         [0021]    Because the cooking oil solidifies at room temperature, the load-out tank  14  can be provided with a heating element which maintains the cooking oil at an elevated temperature, for example 110° F., to ensure it can be readily pumped. As shown in FIG. 5, the heating element  18  can have an L-shaped tubular configuration including a hollow, substantially vertical tube  19  and a hollow, substantially horizontal tube as is described in greater detail in U.S. Pat. No. 5,850,503, which is incorporated herein by reference. The L-shaped heating element  18  is filled with a heat transfer fluid which is heated by a heating coil  22 . In order to help prevent an over pressure condition, a safety valve  24  may be provided on either the horizontal or vertical legs.  
         [0022]    For transferring the waste cooking oil from one or more fryer vats to the load-out station  14 , a piping system is provided. As shown in FIGS.  1 - 3 , the piping system interconnects the load-out station  14  with, in the case of the illustrated embodiment, a plurality of fryers  30 . Adjacent the fryers  30 , the piping system includes a manifold  32  to which the fryers are connected. In particular, the manifold  32  can be connected to the filter systems of the individual fryers by respective high temperature hoses  34  or any other suitable conduits. Each of the connections can include a respective on/off valve  33  that can be used to control the flow of waste cooking oil from the fryer  30  into the piping system. In the illustrated embodiment, a check valve  35  is provided in the manifold  32  downstream from the connections  34  to the individual fryers  20  to prevent waste cooking oil from back-flowing into the manifold.  
         [0023]    In the illustrated embodiment, a substantially vertical pipe segment  36  is located just downstream of the manifold. This vertical segment  36  can be located out of sight such as inside an interior wall of the restaurant and serves to raise the piping system to a level at which it is out of the way, in this instance, above the ceiling  38  of the restaurant as shown in FIG. 3. The vertical segment  35 , in turn, connects into a substantially horizontal pipe segment  40  that extends across the restaurant to where the load-out tank  14  is located. There, another vertical pipe segment  42  (see, e.g., FIG. 4), which again can extend inside a wall of the restaurant, is provided that brings the piping system down to a level at which it can be tied into the load-out tank  14 . In this case, the piping system includes a final segment  44  which extends through an exterior wall  46  of the restaurant to the load-out tank  14  as best shown in FIG. 4.  
         [0024]    To prevent the waste cooking oil from accumulating, the horizontal piping segments can be sloped such that the waste cooking oil will drain towards the load-out station  14  such as shown in FIG. 3. The interior of the piping also can be coated so as to facilitate drainage of the cooking oil. In cases where sloping the piping is not an option, for example, because of the long distance between the fryers and the load-out tank and the limited space above the drop ceilings in the restaurant, at least the substantially horizontal segments of the piping system can be heated so as to prevent the cooking oil therein from solidifying. For example, the piping can be heated by surrounding the metal piping with a pipe jacket filled with a heat transfer fluid. The heat transfer fluid can be heated via a heating element and circulated through the pipe jackets by a pump.  
         [0025]    For moving the cooking oil through the piping system to the load-out tank  14 , one or more pumps may be provided. For example, in the illustrated embodiment, the filter pumps  50  (shown schematically in FIGS. 1 and 2) provided in the individual fryers  30  are used to force the waste oil through the piping system to the load-out tank  14 . Accordingly, the hoses  34  connecting the manifold  32  to the individual fryers  30  communicate with the respective fryer&#39;s filter pump  50  so that when the on/off valve  33  is opened, the waste oil will be driven by the pump through the hose into the manifold. Alternatively, one or more pumps can be provided in the piping system that are separate from the individual fryers.  
         [0026]    To prevent the load-out tank  14  from overflowing, the system is configured to automatically shut-off when the load-out tank is full. If such overflow protection is not provided there is the possibility that the spent cooking oil could be pumped out of the tank vent and create a hazardous situation for employees of the restaurant as well as unsanitary conditions that could pose a health hazard with regard to the preparation of food. To this end, the load-out tank  14  includes a level sensor  60  such as a float switch that detects when the fluid level in the load-out tank  14  reaches a predetermined level. In one embodiment, the level sensor  60  is in communication with a shut-off valve  52 , for example an electrically operable solenoid valve, in the piping system. In the illustrated embodiment, the shut-off valve  52  is located adjacent the downstream end of the horizontal pipe segment  40 . When the cooking oil in the load-out tank  14  reaches the predetermined level, the level sensor  60  is triggered. This signals the shut-off valve  52  to close, thereby stopping the flow of waste cooking oil to the load-out tank  14 . The level sensor  60  can also communicate with an alarm device such as a horn  62  or indicator light  64  that can provide an audible or visual signal when the load-out tank  14  is full. For example, the horn  62  could be arranged adjacent the fryers  30  that would sound for a predetermined amount of time to signal that the load-out tank  14  was full. The horn  62  could then repeat periodically until the level of cooking oil in the load-out tank  14  is reduced. Alternatively, the system could be configured to shut down the pump  50  when the load-out tank  14  is full or to place the pump  50  into a recycle mode wherein the cooking oil is returned to the fryer  30 .  
         [0027]    A controller  70  can be provided which communicates with and controls the level sensor  60 , shut-off valve  52 , alarm horn or light  62 ,  64  and/or pump  50  as shown in FIG. 6. For example, the controller  70  could be configured to direct the shut-off valve  52  to move from the open to the closed position and actuate the horn  62  and indicator light  64  when the level sensor  60  detects that the load-out tank  14  is full. Alternatively, the controller  70  could direct the pump  50  to shut-off or recycle cooking oil back to the fryer  30  when the level sensor  60  detects that the load-out tank  14  is full. In one embodiment, the control panel for the load-out tank  14  can be modified as necessary to operate as the controller  70 . Examples of suitable solenoid shut-off valve are the Model 8267G23 2-way direct-acting solenoid valve available from Asco and the Type 72228 direct lift diaphragm solenoid valve available from Parker Hannifin. An example of a suitable level sensor is the LS-1959 series single station level switch available from Gems Sensors.  
         [0028]    With the distribution system of the present invention, when it becomes time to change out the cooking oil in a fryer vat, an operator need only open the appropriate on/off valve  33  and activate the pump  50  which drains the cooking oil out of the fryer vat  30 . The waste cooking oil is then directed through the piping to the load-out tank  14 . Once the fryer vat is completely drained, and cleaned, as necessary, the operator can fill the fryer with new cooking oil. Once the load-out tank  14  is filled with spent cooking oil, the system will be automatically shut-off, for example via the shut-off valve  52 , so as to prevent any spillage out of the load-out tank  14 . The cooking oil can be pumped from the load-out tank to a truck which hauls away the spent cooking oil for disposal.  
         [0029]    For fryers using roller pumps, the illustrated arrangement of the solenoid valve is sufficient to shut-off the flow of waste cooking oil to the load-out tank. If the system is connected into a fryer using a gear pump, or if the system otherwise uses a gear pump to move the cooking oil, a recirculation line should be placed in the piping system downstream from the pump.  
         [0030]    An exemplary embodiment of a system according to the present invention that utilizes a gear pump is illustrated in FIG. 7. The system illustrated in FIG. 7 includes a load-out station  14  that is connected to a fryer  30  by a fixed piping system (note components the same or similar to those used in the FIGS.  1 - 6  embodiment are given the same reference numbers). A gear pump  50  is provided which moves the cooking oil through the piping system to the load-out tank  14 . To prevent the load-out tank  14  from overflowing, the piping system again includes a shut-off valve  52  that closes when the cooking oil in the load-out tank  14  reaches a predetermined level and stops the flow of cooking oil to the load-out tank. The piping system also includes a manifold  32  to which a plurality of fryers can be attached.  
         [0031]    To allow for the cooking oil to recirculate back to the fryer  30  when the shut-off valve closes, the illustrated piping arrangement has a recirculation line  80  that extends back to the fryer filter pan  82  from a point downstream of the pump  50 . In this case, a check valve  84  is provided between the gear pump  50  and the tee connection  86  to the recirculation line  80  that prevents flow back to the pump  50 . To ensure that the recirculation line  80  only opens when the shut-off valve  52  is closed, the recirculation line  80  is adapted to be activated only when the pressure in the piping system exceeds a predetermined value (e.g., 60 psi). To this end, the illustrated recirculation line  80  includes a reverse flow check valve  88  which opens the recirculation line  80  back to the fryer filter pan  82  when the pressure in the piping system rises to the predetermined value because of closure of the shut-off valve  52 . When the recirculation line  80  is activated, the pump  50  will continue to recirculate cooking oil back to the fryer pan  82  until the shut-off valve  52  re-opens allowing flow into the load-out tank  14  thereby relieving the pressure in the system.  
         [0032]    It will be appreciated that the filling of the fryer with fresh cooking oil can also be done via a direct connect piping system. With such an arrangement, a tank of fresh cooking oil is provided which is connected to the fryer by piping and the fryer is filled by operation of a pump which transfers the fresh cooking oil from the tank to the fryer through the piping.  
         [0033]    From the foregoing it can be seen that a cooking oil distribution system has been provided which substantially eliminates the need for any manual handling of the waste cooking oil. Accordingly, messy, and potentially dangerous, oil splashing and spilling of hot cooking oil is avoided. Moreover, the cooking oil distribution system much quicker and more efficient than commonly used methods for changing oil in fryer vats which require employees to transfer the used cooking oil away from the fryer.  
         [0034]    While this invention has been described with an emphasis upon preferred embodiments, it will be obvious to those of ordinary skill in the art that variations of the preferred embodiments may be used and that it is intended that the invention may be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications encompassed within the spirit and the scope of the invention.

Technology Classification (CPC): 0