Abstract:
A continuous flow pressurized cooker/blancher cooks a food product by continuously transporting the product on a conveyor system and by forcing steam through or over the surface of the food product. The food product to be cooked may be, but is not limited to, seafood and preferably crustaceans. The cooker/blancher includes an exterior pressurized housing, an infeed weigh hopper, an infeed and an outfeed transfer device, and an internal conveyor system. Each transfer device comprises an internal and an external transfer chamber. A pressure assembly forces steam into the exterior pressurized housing while the transfer device is adapted to maintain a selected pressurized environment.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to a continuous flow pressurized steam cooker/blancher for cooking, steaming or blanching a continuous flow of food product.  
       BACKGROUND OF THE INVENTION  
       [0002]     A conventional continuous process cooker/blancher, an example of which can be seen in Canadian Patent No. 2,087,418 (Hufford), processes food in a continuous fashion without the need for human intervention or handling of the food particles.  FIG. 5  of the drawings shows an example of such a conventional continuous process cooker/blancher. Food particles are transferred from a supply conveyor system to the cooker/blancher apparatus through an upper hopper  14 . In a conventional system, the food particles, having passed through the upper hopper  14  will move into an upper rotary valve  15 . The upper rotary valve  15  may be comprised of several fins resulting in numerous compartments to be filled by food particles and transferred to a conveyor system  16 . After travelling through the pressurized chamber the food particles will fall from the conveyor system  16  into a lower rotary valve  17  and finally out of the cooker/blancher apparatus.  
         [0003]     In the above described prior art cooker/blancher, food product is fed in a continuous fashion into the upper rotary valve  15  and the volume of food processed is controlled only by the speed at which the system is operating and the capacity of the compartments within the rotary valves  15 ,  17 . It is only possible to control the volume of food product being processed by altering the speed of the infeed conveyor, or the speed of the rotary valve, or both.  
         [0004]     Further, damage may occur to food products of a delicate nature when subjected to the rotation with the upper rotary valve  15  or lower rotary valve  17 . In the event that a single compartment may become filled to capacity, any food product near the edge of the fins, may become damaged by pressure or friction forces generated against the circumference of the rotary valves  15 ,  17 .  
       SUMMARY OF THE INVENTION  
       [0005]     It is therefore an object of the present invention to provide an improved pressurized steam cooker/blancher wherein food product is transferred to the system in a more controlled fashion. Additionally, the transfer of the food product from the exterior environment to the interior environment of the cooker/blancher is performed such that damage to the food product is reduced and the overall efficiency of the system improved.  
         [0006]     According to a first aspect of the present invention, there is provided a pressurized cooking/blanching apparatus for processing and cooking/blanching of food products, comprising: an cooking/blanching chamber sealed from the external environment and capable of sustaining an interior pressure elevated above atmospheric pressure, an infeed weigh hopper for receiving and measuring an appropriate amount of food product, a first transfer device to receive product from the infeed weigh hopper and transfer the food product from an environment at atmospheric pressure to an environment of elevated pressure within the cooking/blanching chamber, a conveyor belt inside the cooking/blanching chamber to receive the food product from the first transfer device and to transport the food product within the cooking/blanching chamber, a second transfer device to receive the food product from the conveyor belt, transfer the food product from the elevated pressure environment to an atmospheric pressure environment and to discharge the food product from the cooking/blanching apparatus, and a system controller for electrically controlling the operation of the cooking/blanching apparatus.  
         [0007]     The pressurized cooking/blanching apparatus may also comprise a sump positioned near to the bottom of the cooking/blanching chamber to facilitate the collection and removal of any liquid by-product of the cooking/blanching process.  
         [0008]     The cooker/blancher according to the first aspect of the present invention may further comprise a recirculating water system for cushioning and protecting the food product. The recirculating water system preferably introduces water into the first and second transfer device prior to the contact of the food product therewith, thereby providing additional suspension and protection for the food product while being transferred.  
         [0009]     The first and second transfer device preferably each comprise a first transfer chamber for transferring the food product to or from the conveyor belt, a void area to allow for pressurization or de-pressurization of the food product, and a second transfer chamber for transferring the food product into or out of the cooking/blanching apparatus, the first and second transfer chambers each being adapted to form pressure seals with the void area.  
         [0010]     The cooker/blancher according to the first aspect of the present invention may further comprise a rotational speed controller for controlling the rotational speed of the first transfer chamber of the first transfer device. By adjusting the rotation speed of the first transfer chamber, the food product can be evenly distributed onto the conveyor belt resulting in a more efficient use of steam and a more consistent processing.  
         [0011]     While it is preferred for the pressurized cooking/blanching apparatus of the present invention to operate under continuous flow, for continuous processing and cooking/blanching of the food products, it is also envisioned that the cooker/blancher may also be used in a batch format.  
         [0012]     According to a second aspect, the invention further provides a transfer device for transferring food products to or from a pressurized cooking/blanching apparatus. The transfer device comprises a first transfer chamber, a second transfer chamber, and a void area capable of selectively forming a pressure seal with one or both of the first and second transfer chambers. The void area is situated between the first and second transfer chambers.  
         [0013]     Movement of the first and second transfer chambers of the transfer device may be effected by a variety of mechanical means, such as actuation cylinders that hydraulically or otherwise drive the movement of the transfer chambers.  
         [0014]     As a third aspect of the invention, there is also provided a method for transferring food products between an outside environment and a pressurized environment. The method comprises a first step of forming a pressure seal between the pressurized environment and an internal transfer chamber; a second step of introducing food product from the outside environment into an external transfer chamber; a third step of lowering and rotating the external transfer chamber to transfer the food product through a void area and into the internal transfer chamber; a fourth step of rotating and raising the external transfer chamber to form a pressure seal between the void area and the outside environment; a fifth step of raising the internal transfer chamber thereby increasing pressure in the void area and the internal transfer chamber to pressure equivalent to the pressurized environment; and a sixth step of rotating the internal transfer chamber and depositing the food product into the pressurized environment.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     A preferred embodiment of the invention is described below with reference to the accompanying drawings, in which:  
         [0016]      FIG. 1  is a perspective view of a continuous flow pressurized cooker/blancher of the present invention;  
         [0017]      FIG. 2  is a cross-sectional view of a continuous flow pressurized cooker/blancher of the present invention as shown in  FIG. 1 ;  
         [0018]      FIG. 3  is a perspective view of a transfer device according to the present invention;  
         [0019]      FIG. 4  is a cross-sectional side view of a continuous flow pressurized cooker/blancher of the present invention as shown in  FIG. 1 ; and  
         [0020]      FIG. 5  is a side cross-sectional view of a conventional continuous flow cooker/blancher. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]     Referring to  FIG. 1 , in a continuous flow pressurized cooker/blancher, according to the present invention, an infeed conveyor (not shown) is positioned above a storage hopper (not shown). The storage hopper (not shown) is positioned above the infeed weigh hopper  3  connected at one end of the main housing, or cooking/blanching chamber  1  of the cooker/blancher. Positioned at the bottom of the opposite end of the main housing  1 , is a discharge chute  6 .  
         [0022]     Referring to  FIG. 2 , enclosed within the infeed weigh hopper  3  is an upper external transfer chamber  4  and an upper internal transfer chamber  5 , connected at a base flange  11 , forming an upper void area  9 . Below the upper internal transfer chamber  5 , one end of a conveyor belt  2  is positioned. The conveyor belt  2  travels substantially horizontally, and below the opposite end a lower internal transfer chamber  8  can be found. The lower internal transfer chamber is connected from above to the lower external transfer chamber  7  via a second base flange  11 , forming the lower void area  10 . Below the lower external transfer chamber  7 , the discharge chute  6  can be found.  
         [0023]     The infeed conveyor (not shown) moves food product from a storage hopper (not shown) into the infeed weigh hopper  3 . A system controller (not shown) is electrically connected to the infeed weigh hopper  3  such that the infeed weigh hopper  3  may signal the system controller (not shown) to stop the infeed conveyor once the infeed weigh hopper  3  is filled to a correct level. When the infeed weigh hopper  3  is again ready for product, it will signal the system controller (not shown) to start the infeed conveyor (not shown) to again begin transferring food product.  
         [0024]     Referring to  FIG. 2 , the infeed weigh hopper  3  meters an amount of food product necessary to fill the upper external transfer chamber  4 . When further food product is required, the infeed weigh hopper  3  signals the system controller to run the infeed conveyor (not shown) until a preset amount of food product is in the infeed weigh hopper  3 . The infeed weigh hopper  3  then signals the system controller (not shown) to stop the infeed conveyor (not shown). Once the infeed weigh hopper  3  has been filled, and the upper external transfer chamber  4  is ready for product, the infeed weigh hopper  3  releases the food product into the upper external transfer chamber  4 .  
         [0025]     Once food product has been transferred to the upper external transfer chamber  4 , the system controller (not shown) checks to ensure the upper internal transfer chamber  5  is in a sealed position suitable for receiving product from the upper external transfer chamber  4 . The system controller (not shown) then vents the upper void area  9  between the upper external transfer chamber  4  and the upper internal transfer chamber  5  to atmospheric pressure, equalizing the pressure across the upper internal transfer chamber  5  and the upper void area  9 . The void area pressure is examined by the system controller (not shown) to ensure that it is at atmospheric pressure and that there are no leaks. The upper external transfer chamber  4  is then raised, breaking its seal with the upper void area  9 , and then the upper external transfer chamber  4  is rotated by 180 degrees, dumping the food product into the upper internal transfer chamber  5 . The upper external transfer chamber  4  is then rotated 180 degrees in the reverse direction, and lowered to reseal with the upper void area  9 . When the upper external transfer chamber  4  is returned to the original, ready position, the infeed weigh hopper  3  is signaled by the system controller (not shown) to deliver additional food product.  
         [0026]     The upper void area  9  and upper internal transfer chamber  5  are then charged with steam from inside the main housing  1  via a steam inlet valve. The pressure within the upper void area  9  is then examined to ensure that it is at equilibrium with the pressure inside the main housing  1  of the cooker/blancher.  
         [0027]     With food product in the upper internal transfer chamber  5  at the elevated pressure of the main housing  1 , the upper internal transfer chamber  5  is then lowered, breaking its seal with the upper void area  9 , and rotated 180 degrees, emptying its contents onto the internal conveyor belt  2 .  
         [0028]     The upper internal transfer chamber  5  is then rotated 180 degrees in the reverse direction, and raised to seal with the upper void area  9 . The upper void area  9  is then vented to atmospheric pressure, and the pressure checked by the system controller (not shown) completing one complete cycle of food product loading.  
         [0029]     Inside the main housing  1 , the conveyor belt  2  travels at such a rate as to expose the food product to the pressure and temperature inside the main housing  1  for a desired amount of time. The conveyor belt  2  may run at a selectable, but fixed speed, such that the duration of time the food product is on the belt relates to the cook/blanch time. Alternatively, the conveyor belt  2  may be encoded, allowing the system controller (not shown) to track the location on the belt of each load of food product.  
         [0030]     The lower interior transfer chamber  8 , lower void area  10 , and lower external transfer chamber  7  are operated in a manner analogous to the infeed operation.  
         [0031]     Condensate from the cooking/blanching steam and liquid from the food product will accumulate in the bottom of the main housing  1 . Liquid removal means may therefore be provided to remove and recover this liquid while the system is in process. The main housing  1  is typically mounted at a slight angle to allow the liquid to flow to one end of the main housing  1 . At that end, the collected liquid may pass through a sump valve (not shown) into a discharge sump (not shown). The sump valve (not shown) between the sump (not shown) and the main housing  1  are then closed and the sump (not shown) brought to atmospheric pressure. A lower discharge valve (not shown), situated at the bottom of the sump (not shown), may then be opened, emptying the sump (not shown) of the liquid contained within.  
         [0032]     The system controller (not shown) may control the sump valve (not shown) and the lower discharge valve (not shown) upon receiving an electric signal from a level switch (not shown), which indicates the necessity to empty the sump (not shown). A cooling device (not shown) may also be included to reduce the temperature of the collected liquid to a safe and manageable level.  
         [0033]      FIG. 3  depicts an embodiment of the transfer device of the invention. As shown, the transfer device comprises the aforementioned upper external transfer chamber  4  and the upper internal transfer chamber  5 . The transfer device also comprises a plurality of actuation cylinders  12  and one of more chamber positioning arms  13 . When the system controller determines that the position of the upper external transfer chamber  4  or the upper internal transfer chamber  5  is to be changed, a signal is sent to the actuation cylinders  12 , and the chamber positioning arm  13  is moved, thereby moving the associated transfer chamber into the desired position. The void area (not shown) between the upper external and upper internal transfer chambers  4 ,  5  is formed by the base flange  11 .  
         [0034]     Referring to  FIG. 4 , and in contrast to the conventional cooker/blancher as shown in  FIG. 5 , the cooker/blancher of the present invention comprises the infeed weigh hopper  3  positioned above and in cooperation with the upper transfer device  18 . Below the upper transfer device, a first end of the conveyor belt  2  is positioned. The discharge chute  6  is positioned below and in cooperation with the lower transfer device  19 .  
         [0035]     The foregoing are exemplary embodiments of the present invention, and a person skilled in the art would appreciate that modifications to these embodiments may be made without departing from the scope of the invention as defined in the appended claims. All documents identified above are herein incorporated by reference.