Abstract:
A deep fryer having a plurality of fryer pots disposed in the deep fryer. Each of the plurality of fryer pots having a first temperature sensor, a second temperature sensor a drain valve and return valve. The system further has a controller that is pre-programmed to count a number of cooking cycles. After the first temperature sensor senses a first predetermined temperature, oil drains from the fryer pot through the drain valve and when the second temperature sensor senses a second predetermined temperature the oil has substantially returned to the fryer pot through the return valve.

Description:
[0001]    This application claims benefit of U.S. Provisional Patent Application Ser. No. 60/962,046 filed on Jul. 26, 2007, the contents of which are incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This disclosure relates to deep fryers for the food service industry. More particularly, this disclosure relates to deep fryers that are capable of filtering used oil to conserve the oil and to the oil filtering process. Still more particularly, this disclosure relates to deep fryers that are capable of filtering used oil to conserve the oil and to the oil filtering process wherein the process uses thermal sensor feedback to monitor the location of oil in the fryer. 
         [0004]    2. Description of Related Art 
         [0005]    Deep fryers are a necessity of the food service industry and particularly for the fast food service industry. Deep fryers use a substantial amount of shortening or oil during the cooking process. During the cooking process much of the oil is absorbed by a food product, resulting in loss of oil volume. The remaining oil can become filled with debris due to constant use. Accordingly, there is a need to extend the usable life of the unabsorbed oil and to keep the unused oil clean during the cooking process. 
         [0006]    Accordingly, there is a need for a deep fryer that automatically filters used oil in a continuous filtering loop using sensor feedback. 
       SUMMARY OF THE INVENTION 
       [0007]    The present disclosure provides for a deep fryer that filters used cooking oil to extend the life of the cooking oil, using feedback from temperature sensors. 
         [0008]    The present disclosure also provides for a deep fryer that has a closed loop oil filtering system for removing debris from the cooking oil. 
         [0009]    The present disclosure provides for a deep fryer system that is capable of filtering oil using temperature sensor feedback to ensure correct location of the oil in the deep fryer. 
         [0010]    The present disclosure further provides for a method of filtering cooking oil in a deep fryer that is based on feedback from temperature sensors in the deep fryer. 
         [0011]    The present disclosure still further provides for a method of filtering cooking oil for a plurality of fryer pots using a manifold to collect cooking oil and a pump associated with each deep fryer. 
         [0012]    The present disclosure further provides for a plurality of fryer pots that are controlled using a centralized system that uses sensory feedback to ensure filtering steps are performed in the correct timed sequence. 
         [0013]    The present disclosure provides for a deep fryer that provides at least two sensors; one of the two sensors is a temperature sensor to ensure oil is in the deep fryer to commence the filtration cycle and the other of the two sensors ensures that the oil has reached the desired height in the pot during the filler operation. 
         [0014]    The present disclosure still yet further provides for a deep fryer having slots at its lower edge proximate the oil return valve to disperse oil in a spray pattern, the spray pattern ensures that crumbs on the bottom surface of the deep fryer will be flushed. 
         [0015]    Accordingly, there is a need for a centralized process that controls the automatic filtering operation of a deep fryer having a plurality of fryer pots, by using feedback from temperature sensors and timers that control the operation of the pumping and filling operations in each pot. 
         [0016]    These and other further benefits and features are provided by an automatic filtration system for cooking oil in a deep fryer having a plurality of fryer pots disposed in the deep fryer. Each of the plurality of fryer pots having a first temperature sensor, a second temperature sensor, a drain valve and return valve. The system further has a controller that is capable of counting the number of cooking cycles of a particular fryer pot. After the first temperature sensor senses a first predetermined temperature, oil drains from the fryer pot through the drain valve and when the second temperature sensor senses a second predetermined temperature the oil has substantially returned to the fryer pot through the return valve. 
         [0017]    An automatic filtration system for cooking oil in a deep fryer having a deep fryer and a plurality of fryer pots disposed in the deep fryer. Each of the plurality of fryer pots having a first temperature sensor, a drain valve, a second temperature sensor, a return valve associated therewith and at least one slot proximate the drain valve. The system further includes a controller. After the first temperature sensor senses a first predetermined temperature, oil drains from the fryer pot through the drain valve and when the second temperature sensor senses a second predetermined temperature the oil returns to the fryer pot through the return valve and the at least one slot. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    Other and further benefits, advantages and features of the present invention will be understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference characters denote like elements of structure and: 
           [0019]      FIG. 1  illustrates a top perspective view of a deep fryer having two fryer pots, each fryer pot having two temperature sensors, according to the present invention; 
           [0020]      FIG. 2  illustrates a front view of the deep fryer of  FIG. 1  according to the present invention; 
           [0021]      FIG. 3  illustrates a rear view of the deep fryer of  FIG. 1  showing the manifold and filtering system components, according to the present invention; 
           [0022]      FIG. 4  illustrates a top perspective view of the a fryer pot of  FIG. 1  with a heating element and two temperature sensors, according to the present invention; 
           [0023]      FIG. 5  illustrates an exploded view of a filter pan of the present invention; 
           [0024]      FIG. 6  illustrates a side view of the fryer pot of  FIG. 4  having, a linear motion actuators, a drain valve and a return valve, according to the present invention; and 
           [0025]      FIG. 7  illustrates a top perspective view of fryer pot of  FIG. 4 , having spray slots, according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0026]    Referring to  FIG. 1 , a deep fryer is shown, and generally referred to by reference numeral  10 . Deep fryer has a housing  14  and two fryer pots  15  that are each used for cooking the same or different foods. Referring to  FIG. 4 , each deep fryer pot  15  has a heating element  20  proximate to its lower surface. Adjacent to each heating element  20  is a temperature sensor  25 . Each fryer pot  15  also has a temperature sensor  95  located on a side wall to provide temperature feedback as the fryer pot is filled. Sensors  25  and  95  could also be bi-metallic switches or any other temperature sensor capable of providing temperature feedback. 
         [0027]    Deep fryer  10  has a control panel  35  that is associated with each fryer pot  15 . Control panel  35  is operatively connected to a controller  40  that monitors the operation of sensors and timers associated with each fryer pot  15 . Controller  40  can accept various settings, such as, for example, temperature and timing settings. For example, controller is  40  is capable of counting the number of times cooking cycles processed in a fryer pot  15 . After a predetermined temperature has been sensed, and a number of cooking cycles have been counted, the automatic filtration can be initiated. Alternatively, after a predetermined temperature has been sensed, the control panel  35  prompts the user with filter cycle indicator  42 , such as a lamp or an audible indicator for manual operation of the initiation of the automatic filtration cycle with or without a counted number or basket cycles. Controller  35  permits user selection of either automatic or manual operation. 
         [0028]    Referring to  FIGS. 1 through 7 , the components of the oil filtration cycle are described in sequence. Prior to commencement of a filtration cycle, a bubbling period of from approximately 5 to 15 second disturbs any debris that may have come to rest on the inner surface of fryer pot  15 . Air for the bubbling period is introduced to each fryer pot  15  by return valve  90 . Each fryer pot  15  has a drain valve  45  that is opened and closed by a linear actuator  50 . Drain valve  45  has a diameter of approximately 1.25 inches in its fully open position to prevent clogging by debris formed during the cooking process. Linear actuator  50  is either automatically or user activated by operation of controller  40  following prompting by filter cycle indicator lamp  42  on control panel that will commence draining of fryer pot  15 . Beneath each fryer pot  15  is a drain manifold  55  that collects oil from drain valves  45  of each fryer pot  15 . Manifold  55  collects oil from each drain valve  45  in deep fryer  10 . While instant deep fryer  10  shows two fryer pots  15 , there could be as many as twelve fryer pots in a deep fryer. 
         [0029]    Oil passes from drain manifold  55  to crumb basket  65 , via downspout  60 . Crumb basket  65  is a preliminary filter that removes large pieces of residual food product from oil. Referring to  FIGS. 4 and 5 , after oil passes through crumb basket  65 , it is deposited in filter pan  70 . As oil passes through filter pan  70 , it is pulled through a filter pad  72  located in the bottom of filter pan  70 . Filter pad  72  has a series of ridges and grooves on the lower surface thereof to permit oil to flow around pad  72 . Filter pan  70  contains a hold down ring  71  to maintain position of filter pad  72 . Filter spout  75  and filter spout receiver  80  transfer filtered oil to filter pump and motor assembly  85 . Filter pump and motor assembly  85  push oil through return valve  90 , when it is in an open position, to return oil to fryer pot  15 . Return valve  90  is opened and closed by a linear actuator  52 . Return valve  90  has a much smaller diameter of approximately 0.5 inches, in comparison to drain valve  45 . Drain valve  45  must be able to accommodate debris from bottom of fryer pot whereas, oil entering return valve  90  would have already been filtered by crumb basket  65  and filter pad  72 . 
         [0030]    Referring to  FIGS. 2 through 7 , the process of filtering the oil will be described. Cooking oil must be of a temperature that is warm enough to support a filtration cycle so that oil may freely flow through filtering cycle components. The oil temperature must be in a range of from 270° F. to 300° F. If oil is too cool to commence a filtration cycle, feedback from temperature sensor  25  immersed in oil prevents initiation of an automatic filtration cycle. Alternatively, a user can disable the filtration cycle and warm the oil to an acceptable temperature. Once the oil has reached an acceptable temperature, such as above 270° F., linear actuator  50  can be actuated to open drain valve  45  and allow oil to drop into manifold  55 . The user can also initiate the filtration cycle after the acceptable temperature has been sensed, based upon the number of basket uses or if within their judgement a filtration cycle is needed. 
         [0031]    Once a substantial amount of oil has drained from fryer pot  15  into filter pan  70  from manifold  55 , temperature sensor  25  in fryer pot  15  is exposed to an ambient air temperature. When temperature sensor  25  senses a 10° F. to 20° F. temperature drop below the set oil temperature, controller  40  energizes linear actuator  52  to open return valve  90  and pump and motor assembly  85  are switched on to return oil back to fryer pot  15 . Sensor  25  senses a temperature of from approximately 250° F. to 280° F. The pumping action pulls the oil through filter pad  72  located in the bottom of filter pan  70  and forces clean filtered oil through return valve  90 . The temperature drop sensed by sensor  25  informs controller that oil is no longer in fryer pot  15  and that pump and motor assembly  85  can be switched on to commence filling of fryer pot  15 . Were filtration system only time based, the pump and motor assembly  85  may improperly commence operation and run in the absence of oil and cause premature component failure. 
         [0032]    After filtered oil is pushed through opened return valve  90 , it is forced through a narrow slot or several slots  100  at lower edge of fryer pot  15  and sprayed over fryer pot lower surface. These slots are from 2 to 5 inches long, 0.05 to 0.10 inches in height, and from 1 to 5 in number. The force with which oil is sprayed back over lower surface of fryer pot  15  is strong enough to push remaining heavy debris that did not initially flow through drain valve  45  at commencement of filtering cycle, but not so great as to force oil to splash out of the fryer pot  15 . By having an oil flow rate of approximately 3 to 9 gallons/minute through a limited size pump and motor assembly  85 , oil is prevented from splashing out of fryer pot  15 . The sprayed oil and additional debris will then flow through drain valve  45 . The amount of time for spraying the oil from return valve  90  back and though the drain valve  45  is predetermined and set in controller  40  for a duration of 15 to 30 seconds. During this time, cooking oil is repeatedly cycled through filtration system. After 15 to 30 seconds, linear actuator  50  is activated to close drain valve  45  while pump and motor assembly  85  return oil to fryer pot  15 . The repeated or polishing cycles filters the oil to ensure that substantially all food particles have been removed from the cooking oil and the fryer pot  15 . The polishing filtration cycles eliminate the need for the cooking oil to be replaced prematurely and therefore extends the useful life of the cooking oil. Further the centralized control of drain valve  45 , return valve  90 , and pump and motor assembly  85  provides sensory feedback to ensure that the filtering cycle is performed in the correct timed sequence. 
         [0033]    Approximately 15 to 30 seconds after drain valve  45  is closed, heating elements  20  are automatically energized to warm cooking oil that has been returned to fryer pot  15 . After 20 to 45 more seconds, the volume of cooking oil in fryer pot  15  is great enough so that temperature sensor  95  on fryer pot wall is able to sense an increase in temperature because it is immersed. When sensor  95  senses approximately 5 to 10 seconds of rising temperature the oil is considered to be returned substantially to the pot. Twenty to forty-five additional seconds of bubbling insure that the oil is completely returned to the fryer pot from filter pan  70 . At this time, pump and motor assembly  85  are de-energized and linear actuator  52  is energized to close return valve  90 . 
         [0034]    While the instant disclosure has been described to incorporate linear actuators, either hydraulic or pneumatic pistons could also be used for opening and closing the drain and return valves of the instant disclosure. 
         [0035]    The present invention having been thus described with particular reference to the preferred forms thereof, it will be obvious that various changes and modifications may be made therein without departing from the spirit and scope of the present invention as defined in the disclosure.