Abstract:
A steam cooking system includes a steam cooking chamber having an access door and a drain for draining condensate from the steam cooking chamber along a drain path. A steam generator unit heats water to generate steam. The steam generator unit is connected for delivery of steam from the steam generator to the steam cooking chamber via a first steam path during a cooking operation. The steam generator unit is also connected for delivery of steam from the steam generator to the drain path via a second steam path during a steam flushing operation.

Description:
TECHNICAL FIELD 
     The present application relates to steam cookers, and more particularly to a steam cooker with steam flushing system. 
     BACKGROUND 
     Steam cookers have been successfully employed by restaurants, hospitals and other food service operations to prepare large quantities of food quickly and conveniently. Increases in productivity and efficiency are regularly sought, for example, to decrease the time and energy needed to cook the products. 
     SUMMARY 
     In an aspect, a steam cooking system includes a steam cooking chamber having an access door and a drain for draining condensate from the steam cooking chamber along a drain path. A steam generator unit heats water to generate steam. The steam generator unit is connected for delivery of steam from the steam generator to the steam cooking chamber via a first steam path during a cooking operation. The steam generator unit is also connected for delivery of steam from the steam generator to the drain path via a second steam path during a steam flushing operation. 
     In another aspect, a method of cleaning a steam cooking system is provided. The method includes generating steam using a steam generator. The steam generator is connected to a steam cooking chamber for delivery of steam to the steam cooking chamber via a first steam path during a cooking operation. The steam cooking chamber has an access door and a drain for draining condensate from the steam cooking chamber along a drain path. Steam is delivered from the steam generator to the drain path via a second steam path during a steam flushing operation. 
     The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagrammatic view of an embodiment of a steam cooking system; and 
         FIG. 2  is a diagrammatic view of the steam cooking system of  FIG. 1  including steam flushing system. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a steam cooker system  10  includes a steam generator  12  for generating steam and a cooking chamber  14  that is in communication with the steam generator. The cooking chamber  14  is formed by an insulated housing and includes a door  16  that is moveable between open and closed positions. In some embodiments not shown by  FIG. 1 , the system  10  may include more than one cooking chamber  14  connected to the steam generator  12 , such as two cooking chambers. 
     Disposed in a heating chamber  18  of the steam generator  12  may be any suitable heating system  20 . In one embodiment, the heating system  20  includes a gas heat exchanger  22  in the form of a submerged heat exchange tube. The heat exchanger  22  is connected to a burner unit  24  (e.g., a metal fiber, fan driven burner) that is capable of generating hot gases for delivery to the heat exchanger. The heat exchanger  22  is located in the heating chamber  18  such that it can be in a heat exchange relationship with water disposed therein. While the illustrated heat exchange relationship is via submersion with the heat exchanger, it is possible that hot gas could pass through ducts that are not submerged, such as ducts that run across the interior wall of the heating chamber  18 . Electric heating elements could also be used. 
     The heating chamber  18  includes an inlet  26  for ingress of water into the heating chamber from a water source and an outlet  28  for egress of water from the heating chamber. A valve  30  may control water flow into the heating chamber, e.g., to maintain a desired water level within the heating chamber  18  during steam production. Water level sensors may be positioned in the heating chamber  18  for this purpose. Similarly, a valve  31  may control water flow from the heating chamber  18  during a flushing operation. 
     Referring now to  FIG. 2 , the steam generator  12  is connected to the cooking chamber  14   a . In some embodiments, as noted above, the steam generator  12  may also be connected to another cooking chamber  14   b  represented by dashed lines. 
     In the illustrated embodiment, a steam header  34  is used to connect steam cooking lines  36   a  and  36   b  to the steam generator  12 . The steam cooking lines  36   a  and  36   b  are, in turn, connected to the cooking chambers  14   a  and  14   b . Steam valves  38   a  and  38   b  are used to control delivery of steam to the cooking chambers  14   a  and  14   b.    
     Cooking compartment drains  40   a  and  40   b  are used for draining condensed water, other liquids and debris from their respective cooking chambers  14 . The cooking compartment drains  40   a  and  40   b  are connected to a drain line  42 , which is, in turn, connected to a condenser  44 . The drain line  42  carries the water, other liquids and debris from the cooking compartment drain  40  to the condenser  44 , where the water, other liquids and debris can be flushed into a floor drain line  46 . Typically, the floor drain line  46  has a diameter that is larger than that of the drain line  42  to facilitate the draining of debris flushed from the drain line. In some embodiments, the outlet  28  of the steam generator  12  is also connected to the condenser  44 . A cooling water line  48  may be used to reduce temperature of the water drained from the steam generator  12  to an acceptable level. The condenser  44  may include a temperature sensor  45  for use in determining the temperature of the fluids and other particles before they enter the floor drain line  46 . In some embodiments, cooling water may be delivered to the condenser  44  if the temperature determined is above a predetermined temperature level permitted by local code. 
     Occasionally, fat and/or oils drained from the steam cooking chamber  14  can build up in the drain line  42 , reducing the effectiveness of the drain path. Accordingly, a steam flushing system, referred to generally as element  50 , is used to flush debris, such as food particles, oils and fats from the drain line  42 . Steam flushing system  50  includes a steam flush line  52  that is connected to the steam generator  12  via the steam header  34 . Thus, in this embodiment, the steam generator  12  selectively supplies steam to the cooking chambers  14  and the steam flushing system  50 . A steam valve  54  controls delivery of the steam through the steam flushing system  50 . In some instances, the steam valve  54  provides steam at rate of between about one lb/hr and about three lb/hr, such as about 2 lb/hr. The rate of steam delivery may vary, however. As can be seen, the steam flush line  52  is connected to the drain line  42 . A check valve  56  is located between the steam valve  54  and the drain line  42  to inhibit reverse flow of steam, liquids and debris thereby. In some embodiments, a compartment drain cooling water line  58  is also connected to the drain line  42  for temperature control in the drain line. 
     As steam is delivered through the drain line  42 , any solidified fats and/or oils will tend to liquefy due to the temperatures effectively cleaning the drain line  42 . In operation, control  70  may include respective connections to the steam generator  12  for controlling production responsive to a cooking chamber interface  72  setting, connections to steam cooking line valves  38  to control delivery of steam to the chambers  14 , and connection to the steam flush line valve  54  to control steam delivery to the drain line  42 . The control may be configured to perform the steam flush operation for the drain line  42  on a timed basis, e.g., periodically as part of a steam generator shut down procedure and/or responsive to a specific control input of the interface  72 . In one embodiment, the steam flush operation is performed upon shut down where steam is delivered to the drain line  42  immediately prior to draining of the steam generator  12 . After steam is delivered to the drain line  42 , the water is drained from the steam generator  12 , into the condenser  44 . In some embodiments, the steam flush operation is not connected to shut down. For example, the steam flush operation may be initiated manually through a user input. 
     In the illustrated two chamber system, a separate steam delivery line  36   b  and associated valve  38   b  is provided for the second chamber  14   b . The drain  40   b  of the second chamber  14   b  is connected to the same drain line  42  as the first chamber  14   a , such that a single steam flushing operation via valve  54  is sufficient to clean the drain paths of both chambers. In an alternative arrangement, the drain path of the second chamber  14   b  is distinct from the drain path of the first chamber  14   a , and two steam flush lines could be provided, one for each drain path. 
     It is to be clearly understood that the above description is intended by way of illustration and example only and is not intended to be taken by way of limitation. Other changes and modifications could be made, including both narrowing and broadening variations and modifications of the appended claims.