Abstract:
A fryer unit includes a boil-out drain path that does not require boil-out fluid to pass through a pump.

Description:
TECHNICAL FIELD 
   The present invention relates generally to deep-fat fryers and, more particularly, to a, deep-fat fryer cooking oil filtration arrangement that includes a boil-out bypass feature. 
   BACKGROUND 
   A typical deep-fat fryer will include a fryer vat containing a heated bath of cooking oil. The cooking oil is adapted to receive baskets of food products such that the food products will be immersed within and cooked by the heated cooking oil. Such fryers include a heat exchanger, which may take the form of in vat fire tubes and associated burners, with combusted gases being passed therethrough to heat the oil. 
   To extend the useful life of the cooking oil, it is a common practice to filter the particulate food matter from the cooking oil to minimize the carbonization of such food matter within the cooking oil. Various configurations of filtering systems in which oil is drained from the vat into a pan, tub or other below unit containment vessel and then passed through a filter have been provided, with a pump used to return oil to the fryer vat after the oil has been filtered. 
   The cleaning process for fryer vats typically involves a “boil-out” process in which the vat is filled with a mixture of oil and vinegar and the heating system of the fryer is run to produce a boiling of the mixture, which in turn cleans the vat. Once the boil-out process is completed, the mixture must be removed from the vat, preferably drained without leaving any significant amount of the mixture in the unit and without running the mixture through the pump, as that may degrade the pump/motor assembly causing early failure. Typically, oil in the vat is drained into the pan, tub or other below unit containment vessel of the oil filtering system prior to the boil-out. Upon completion of the boil-out, including removal of the cleaning mixture, the oil in the vessel is returned to the vat. Since the oil is held in the below unit vessel during boil-out, the below unit vessel is not available for draining of the cleaning mixture. It would be desirable to provide a fryer that facilitates removal or draining of the boil-out cleaning mixture. 
   SUMMARY 
   A fryer unit includes a boil-out drain path that does not require boil-out fluid to pass through a pump. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIGS. 1 and 2  depict a prior art fryer including a filtration arrangement; 
       FIG. 2  is a side elevation of the oil pan and associated filter assembly of the fryer of  FIG. 1 ; 
       FIG. 3  depicts one embodiment of a boil-out drain pipe; 
       FIG. 4  depicts an alternative embodiment of the end of a boil-out drain pipe; 
       FIG. 5  is a partial side view depicting position of the installed boil-out drain pipe; 
       FIGS. 6 and 7  show an alternative embodiment of a boil-out drain pipe; 
       FIG. 8  shows a schematic of an alternative embodiment using a three way valve; 
       FIG. 9  shows a schematic of en embodiment having a stowable drain pipe. 
   

   DETAILED DESCRIPTION 
   Referring to drawing  FIGS. 1 and 2 , a fryer filtration arrangement similar to that shown and described in U.S. Pat. No. 6,890,428 is shown, with certain modifications made for implementing the boil-out bypass feature. The fryer  10  includes two fryer vats  12 A and  12 B. Each fryer vat includes at least one respective basket  16 A and  16 B which is automatically movable upward and downward via respective positioning guides  18 A and  18 B in a manner well known in the art. Manual raising and lowering of the baskets is also possible in some fryers. The fryer  10  includes a frame  20  which preferably includes associated housing  22  such as stainless steel. A front panel  24  of the fryer  10  includes a control and display panel  26 A and  26 B for each fryer vat. The lower portion of the housing frame includes a set of doors  30 A,  30 B which are movable between open and closed positions, and which are illustrated in the open position. Below the doors  30 A,  30 B a drawer  32  which is movable between open and closed positions relative to the frame  20  is provided, the drawer being illustrated in the open position. Positioned within the drawer  32  is an oil receiving pan  34  having a rim  36  which sits on rails  38  of the drawer  32 . Handles  40  extend from the interior sidewalls of the pan  34  to allow the pan to be easily picked up and removed from the drawer to facilitate cleaning at a location away from the fryer  10 . Positioning of the handles  40  on the inner portion of the pan helps facilitate simple positioning of the pan in the drawer  32 . As used herein, the term “pan” is intended to broadly encompass any oil receiving container, unless otherwise specifically indicated. 
   A basket type screen  42  is removably positioned within the pan  34  for filtering out debris entering the pan  34  within oil which is drained from one of the fryer vats  12 A and  12 B. At the bottom of the pan  34  a filter assembly  45  is provided for filtering the oil. An oil return path from the pan  34  back to the fryer vat  12 A,  12 B is formed in part by a coupler  44  which is connected to and extends from a front sidewall of the pan  34 . The illustrated coupler  44  extends rearwardly back toward the fryer frame  20 . A corresponding coupler  46  ( FIG. 2 ) is positioned on the fryer frame  20 , with the two couplers aligned for slidingly mating with each other in a friction fit arrangement when the drawer  32  is moved to a closed position. 
   In the illustrated fryer  10 , each vat  12 A,  12 B includes an associated exhaust stack  200 A,  200 B formed at the back of the fryer for venting combustion gases produced by the oil heating system which includes in vat fire tubes. 
   Referring now to  FIG. 2 , the pan  34  includes an outlet opening  48  through its bottom wall  50 . The oil return path is formed in part by a flow passage through member  52  and piping  54  which runs along the external surface of bottom wall  50  and front wall  56  of the pan  34 . 
   Near the top of front wall  56  a wall penetrating coupling assembly  58  passes through the wall  56 , with piping  60  extending upward from the pan  34  and rearwardly as shown. The end of piping  60  acts as the return coupler  44 . The return coupler  44  mates with corresponding coupler  46 . 
   The oil return path leads back to the fryer vat and includes a pump  110 , which may be driven by an electric motor, positioned therealong for drawing oil out of the pan  34  and pumping it back to the vat. Oil traveling out of the pan  34  during a filtration operation travels from the pan  34 , through the outer filter screen material of the filter assembly  45 , into the interior of the filter assembly  45 , and out of the interior of the filter assembly  45 . Operation of the pump  110 , and the associated flow of oil drawn out of the pan  34 , creates a suction force for holding the coupler of the filter assembly  45  to the coupler of the pan  34 , without requiring any latch or hold down member. The suction force created by the pump  110 , and the associated flow of oil drawn out of the pan  34 , also holds the return coupler  44  of the pan  34  to the corresponding coupler  46  of the fryer frame  20  so as to maintain the drawer  32  in a closed position during a filtration operation, without requiring any positive latch. 
   In  FIG. 2 , the fryer vat  12 B is shown. An outlet opening  120 B in a wall of the  12 B leads to a draining pipe  122 B. The draining pipe  122 B leads to a drain pipe/manifold  124  which extends laterally across a front portion of the fryer  10  as seen in  FIG. 1 . The drain pipe  124  includes an outlet  126  for delivering oil into the pan  34 . Fryer vat  12 A includes a similar drainage path to the manifold  124 . Thus, each vat  12 A,  12 B includes a respective oil drain path extending from its outlet opening to the pan  34 . Positioned along each oil drain path is a flow control device  130 A,  130 B for controlling the draining of each vat. In particular, each flow control device may be a manually operable valve including a respective handle  132 A,  132 B for permitting a user to open and close the drain path as desired. Of course, other flow control devices may be used, including automatically controlled devices. 
   In connection with the boil-out cleaning process, one vat at a time is typically cleaned. For example, with respect to vat  12 B, drain valve  130 B would be opened to allow the oil from vat  12 B to drain into the pan  34 . The oil may be circulated through the vat  12 B, pan  34  and filter  45  for a period of time to filter out debris. The drain valve  130 B is then closed. The vat  12 B can then be filled with the cleaning fluid, which as described above may be a combination of oil and vinegar. The heating system for vat  12 B is then operated to bring the cleaning fluid to a boil for a cleaning time period, after which the cleaning fluid can be removed from the vat  12 B. In this regard, the manifold  124  includes boil-out drain opening  300 B that is typically covered by a cap member  302 B, which may have an associated tether  304 B to avoid loss of the cap member when removed. The opening  300 B is located in line with the drain path pipe  122 B and the drain valve  130 B. In the illustrated 2-vat fryer, a similar boil-out drain opening and cap member  302 A is provided in line with drain valve  130 A (see  FIG. 1 ). The boil-out drain openings are adapted to receive a drain pipe as will be described in detail below. 
   Referring now to  FIG. 3 , in one embodiment, the boil-out opening  300 B is internally threaded to threadingly receive the drain pipe  310 . The cap member may likewise include external threads for closing the opening. The illustrated boil-out drain pipe has an unthreaded drain end  312 , an externally threaded middle coupling portion  314  and an unthreaded, smaller diameter extension  316  which passes through diametrically opposite opening  320 . Opening  320  includes an associated mount flange  322  to which the drain valve  130 B (not shown) can be coupled. The end of extension  316  may be sized and configured for seating against an internal portion of the drain valve so that, with drain pipe  312  in place, when the drain valve is opened, the boil-out cleaning fluid bypasses the manifold  124  and instead passes directly along the drain pipe path  324  and out of the drain pipe  310 , thereby avoiding mixing of the boil-out cleaning mixture with the oil in the pan. Once the boil-out cleaning mixture is drained, the valve is closed and the drain pipe is unthreaded from opening  300 B. The cap member is then replaced, returning the fryer unit to its normal operating configuration. Referring to  FIG. 4 , in an alternative embodiment; the end of the extension  316  could be tapered as shown, for seating against the inside surface of the flange  322 . Referring to the partial side view of  FIG. 5 , note that the boil-out drain pipe  310  can be installed with the drawer unit in its closed position, and extends forward of the drawer unit, enabling a boil-out container  330 , such as a bucket or pan, to be placed in the front of the unit to receive the draining boil-out cleaning fluid. This feature is advantageous because, in many cases, the pan  34  will contain the vat oil and it would be undesirable to have to pull the pan out in such instances. 
   Referring now to  FIGS. 6-7 , another embodiment is shown in which boil-out opening  300 B includes a flange  331  that is externally threaded (in which case the cap member is internally threaded for attachment). The boil-out drain pipe  310 ′ passes through opening  300 B without connection thereto. The opening  320  is includes an internally located threaded coupling  332  for receiving the end  334  of the drain pipe  310 ′ which is correspondingly threaded. Similar to  FIG. 5 , the drain pipe  310 ′ may extend out past the drawer when installed, facilitating positioning of a boil-out cleaning fluid receiving vessel. 
   Thus, for a typical boil out of a given vat, oil is drained from the vat into the pan by opening the drain valve. The drain valve is closed. The vat is filled with the boil-out cleaning fluid. The heating system of the vat is operated for a cleaning time period. The cap member associated with the boil-out opening for the vat is removed. The boil-out drain pipe is installed. The boil-out cleaning fluid vessel is positioned in front of the fryer below the outlet of the boil-out drain pipe. The drain valve associated with the vat is opened, allowing the boil-out cleaning fluid to exit the unit via the boil-out drain pipe, bypassing the manifold. The valve is closed. The boil-out drain pipe is removed. The cap member of the boil-out opening is put back in place and the drain valve is closed. The oil in the pan is pumped back into the vat. In this way, the pump need not be used for moving the boil-out cleaning fluid, and the under unit oil-receiving pan or other vessel can be kept in place during the entire boil-out process. 
   In an alternative embodiment, as shown in  FIG. 8 , the valve  132 B could be replaced by a three way valve. In one position, the valve is closed, preventing the contents of the vat from draining. In a second position the valve is opened to allow oil to be drained into the manifold  124  and ultimately into the oil-receiving drain pan  34 . In a third position the valve is opened to a allow the boil-out cleaning liquid to be diverted by a separate drain line/boil-out drain pipe, which need not be associated at all with the manifold, to a receptacle  330  for disposal. In one embodiment of this implementation the separate boil-out drain pipe may be a component that is not regularly removed from the fryer. Instead, and as shown in  FIG. 9 , the boil-out drain pipe  310 ″ could be movable, as by rotation per arrow  350 , between a stowed position within the fryer (shown in dashed line form) and a use position in which the boil-out drain pipe extends forward of the front of the fryer (shown in solid line form). 
   Various boil-out drain pipe constructions have been shown and described. Regardless of the exact construction, the pipe may be formed as a single piece or as multiple different pieces coupled together as by press fitting or welding. The boil-out drain pipe could also be formed, in part or in whole, of a flexible or hose-like material. It is also recognized that the boil-out bypass path could be used for draining oil from the vat into a front located receptacle such as receptacle  330  of  FIG. 5 . 
   Variations on the foregoing are possible. For example, while a fryer including two vats has been shown above in the illustrated embodiment, fryers including more or less vats could incorporate the subject boil-out drain feature. While the various constructions have been described primarily in conjunction with vat  12 B, it is recognized that in a multi-vat fryer apparatus each fryer vat could readily include a similar boil-out bypass feature.