Abstract:
The present invention relates to an improved, simplified apparatus for rapidly cooking food in heated water with the assistance of increased pressure that provides the benefits of improved stirring capabilities, increased simplicity of the apparatus, and improved self-cleaning capabilities.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 09/785,509, now U.S. Pat. No. 6,360,652, filed on Feb. 16, 2001. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus for rapidly cooking food in heated water with the assistance of increased pressure. 
     2. Discussion of the Related Art 
     The relevant art teaches several automatic apparatuses for rapidly cooking, with increased pressure, doses of pasta in a relatively short time period. Generally, such automatic apparatuses are designed to cook pastas in a two-step process. The pasta is first exposed to high-temperature, high-pressure water for a brief period of time. The pasta is then exposed to heated water at a pressure and temperature that is lower than that which is used during the first stage of the cooking cycle to allow the pasta to continue cooking, and to absorb an appropriate amount of water. After the second stage of the cooking cycle, the pasta is then separated from the water. Once separated, the pasta is ready for consumption. 
     The apparatuses taught in the relevant art have several drawbacks. While some apparatuses are designed to allow an influx of water into the first cooking chamber to stir the pasta being cooked, this frequently is not sufficient. As a result, individual pieces of pasta tend to adhere to each other. Additionally, due to the apparatuses&#39; enclosed design, they are difficult to clean. While it is possible to run a cooking cycle without the pasta to flush the apparatus with water, simply filling the apparatus with water, without more, does not sufficiently remove food residue from the interior of the apparatus. An improved apparatus that will alleviate these problems is desired. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a view of a process diagram according to an embodiment of the present invention; 
     FIG. 2 illustrates a perspective view of one embodiment of the present invention, with the exterior panels partially shown; 
     FIG. 3 illustrates a perspective view of a cooking stack according to an embodiment of he present invention; 
     FIG. 4 illustrates an exploded perspective view of a cooking chamber according to an embodiment of the present invention; and 
     FIG. 5 illustrates a cross-section of a cooking stack according to an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     The apparatus of the present invention is capable of cooking virtually any food product that may be cooked using overheated water and steam. Such foods include pastas, grains, vegetables, prepared frozen foods, seafood, and meats. The invention may be made in larger sizes to accommodate industrial amounts of food, and in smaller sizes to prepare smaller quantities of food. 
     Intake water that is used with the present invention may come from any suitable supply, such as a community water system. In the preferred embodiment of the present invention, the intake water is put through a water filter and a water softener prior to entering the main body of the present invention. This helps to ensure regular operation and reduces service and maintenance costs. Water entering the present invention may pass through an intake line pressure switch  32 . This switch  32  ensures that pump  20  does not receive an inrush of water at greater-than-expected pressures. 
     The apparatus according to one embodiment of the present invention may be viewed as composed of essentially 4 components, the combination of which will be referred to as the apparatus: the boiler; the cooking stack or system; the programmable logic controller (PLC); and various accessories. The boiler primarily provides overheated water to the cooking system. The cooking stack is primarily composed of a cooking chamber  46 , where the food is initially exposed to pressurized, heated water, and a conditioning chamber  38  where the food may absorb additional water and flavorings. The PLC may be a standard industry control device that is capable of reading electrical signals and generating outputs. The accessories include items that are required to manage water, steam, raw and cooked product, and perform the cycle in a suitable manner. Such items include, but are not limited to, solenoid valves, water pumps, pressure switches, drain lines, and a strainer. 
     FIG. 1 illustrates a view of a process diagram according to an embodiment of the present invention. The boiler  10  is configured to produce heated, pressurized water. In one embodiment of the present invention, this water is preferably heated to a temperature between 160 and 200 degrees Celsius, and pressurized to a pressure between 8 and 14 bar. In order to produce such heat and pressure, the boiler  10  is equipped with at least one heater  11 . In one embodiment of the present invention, as depicted in FIG. 1, there is a plurality of heaters  11 . Preferably, such heaters are metal-clad electrical resistance heaters; however, any appropriate heater as is known in the art may be used. Water enters the boiler  10  through inlet line  100  and leaves the boiler through outlet lines  101 . The inlet line  100  and outlet lines  101  may each have valves as required to control fluid flow. Water is supplied to the boiler  10  through inlet line  100  by a pump, such as positive displacement pump  20 , or any other pump as is known in the art. The positive displacement pump  20  may supply water to the boiler  10  at moderate pressure (2 to 4 bar). 
     The volume of the boiler  10  may vary depending on the intended production capacity of the apparatus of the present invention. In a preferred embodiment of the present invention, the boiler  10  holds approximately 6 liters of water. 
     As noted above, the level switch  13  operates to maintain the water level in the boiler  10 . When the water in the boiler  10  falls below a certain level, level switch  13  may operate to activate the positive displacement pump  20  and open valve  16  and check valve  18 . While such valves may be any appropriate valve as is known in the art, they are preferably solenoid valves. 
     There may be an additional check valve  18  that may operate to prevent hot boiler water from reaching the displacement pump  20  and causing damage if the boiler feed valve  16  fails to open. The temperature of the water inside boiler  10 , is maintained at a set temperature by means of a temperature sensor  12 . This temperature sensor  12  may be installed inside the boiler. This temperature sensor  12  may provide continuous or periodic readings of the water temperature. Preferably, the temperature is maintained above 100° C., and most preferably the water temperature is maintained at 180° C. 
     The pressure in the supply lines, the water level and temperature in the boiler  10 , and he flow of the water through the valves and other control procedures may be controlled by he PLC. Specifically, for example, each time that water is withdrawn from the boiler  10  to begin the cooking cycle, the central processing unit or other suitable device restores the water, temperature and pressure automatically. 
     The programmable logic controller (PLC) (not shown) uses the temperature reading from the temperature sensor  12  to maintain the previously selected temperature in the boiler  10  by controlling the power going to the heaters  11 . For the purposes of this description of the present invention, it is presumed that any embodiment of the present invention would include a power source and all wires, connections, interfaces and power systems necessary to allow the system to interface with the PLC. The PLC may be made accessible to the user at a control box, such as control box  62  (See FIG.  2 ). 
     As show in FIG. 2, the apparatus of the present invention may be encased in an exterior casing (not numbered). This casing serves to contain the system, and may provide some insulation. Such casing may have a frame  60 . 
     As shown in FIG. 1, the boiler  10  may be equipped with several features that serve to ensure first that the boiler  10  will maintain an adequate supply of heated, pressurized water and, secondly, that the boiler  10  does not become over-pressurized. Such over-pressurization could result in rupturing of the system or even explosion of the boiler  10 . In a preferred embodiment of the present invention, there is a level switch  13  that measures the water level in the boiler  10 , and sends signals to the PLC when there is sufficient (or excess) water in the boiler  10 , and when water needs to be added. There is also a thermocouple temperature sensor  12 . Additionally, there may be a pressure switch  30  that interrupts the power going to the heaters  11  and pump  20  if the boiler pressure exceeds a preset pressure threshold may be included. Alternatively, or additionally, there may be a relief valve  15  which may release excess pressure from boiler  10  when the pressure inside the boiler  10  reaches a preset pressure into a line which will route the steam, water and/or air through the system and eventually to the drip tray  52 . If this relief valve  15  is used in conjunction with the pressure switch  30 , the preset pressure should be is higher than the pressure at which the pressure switch  30  is set. In this situation where the two safety devices are used in conjunction, the relief valve  15  acts as a backup system in the case the pressure switch  30  fails. 
     In a preferred embodiment of the present invention, the entire system is insulated in order to minimize heat losses. Such insulation may be any appropriate insulation as is known in the art. 
     The cooking stack, which may be seen in greater detail in FIGS. 3 and 5, is designed to cycle a measured, predetermined amount of food through a two stage cooking process. The food is first exposed to heated, pressurized, water in a cooking chamber  46 , then passed to a conditioning chamber  38  where it may absorb additional water and seasonings, if desired. These seasonings may be initially placed into the system with the food product as it enters the cooking chamber. Alternatively, there may be an opening (not shown) in the conditioning chamber through which a user may add seasonings before the heated water and food enters. 
     The cooking stack is generally composed of a plurality of parts that are aligned in a liner, and preferably vertical, manner. As shown in the figures in varying detail, there is a funnel  34  which leads to the mounting plate  43 . This funnel  34  is preferably coupled to the mounting plate  43 . There is also a cooking chamber  46  located beneath the funnel, in which the product to be cooked is first exposed to the heated, pressurized water. The cooking chamber  46 , has an upper flange  45 , which upper flange is designed to be a swirl flange in the embodiment of the present invention shown in FIG. 4, and a lower flange  47 . An upper ball valve  21  and seal plate  44  are located between the mounting plate  43  and the cooking chamber swirl flange  45 . There is also a vent valve  27 , which may be a solenoid valve, that is associated with the cooking chamber  46  to permit the release of pressure from the cooking chamber  46 . Such release of pressure may be associated with an over-pressurization of the cooking chamber  46 , with a desired agitation of the cooking food, or with the transfer of food from the cooking chamber  46  to the conditioning chamber  38 . 
     The cooking chamber  46  may be located directly below the cooking chamber swirl flange  45 . The cooking chamber  46  may be tube-like in shape, as shown in the figures. However, the cooking chamber  46  may take any shape that permits the ready flow of water and material that is being cooked from the cooking chamber  46  to a conditioning chamber  38 . 
     The cooking chamber  46  is prepared for operation by closing the lower ball valve  22  and opening the upper ball valve  21 . The upper ball valve may be performed by an upper ball valve actuator  40 , while the lower ball valve may be performed by a lower ball valve actuator  41 . The opening and closing of the upper ball valve  21  and the lower ball valve  22  may be controlled by the PLC, or may be designed so that they may be manually opened. Such manual manipulation may be included in one embodiment of the present invention as a safety feature, since it allows a user to bypass the PLC in case the PLC fails to operate appropriately. 
     Uncooked food is fed through the funnel  34  and into the cooking chamber  46 . Movement of the uncooked food through the funnel  34  and into the cooking chamber  46  may be controlled by the opening and/or closing of the upper ball valve  21  and the force of gravity. The upper ball valve  21  is then closed, and hot, pressurized water is allowed to enter the bottom of the cooking chamber  46  through the cooking chamber inlet line  57  until it covers the food to be cooked. Inlet line  57  preferably feeds the heated, pressurized water into the bottom of cooking chamber  46 . This prevents linear pasta and other elongated foods from being broken by the force of the inrush of overheated pressurized water into the cooking chamber  46 , stirs the food being cooked, and facilitates even cooking. 
     The flow of the hot, pressurized water may be controlled by a valve  24 , which may be a solenoid valve, to ensure that the cooking chamber  46  receives sufficient water, yet does not receive too much water. The cooking chamber  46  should be sized such that once it has received the food and the hot, pressurized water, there should be only a small amount of air in the cooking chamber. Due to gravity, the food being cooked is generally located in the lower portion of the cooking chamber  46 , and should be generally covered by the high temperature water. 
     The upper ball valve  21  and lower ball valve  22  provide a high pressure seal that prevents water and/or steam from escaping during the cooking cycle. Additionally, the cooking chamber  46  is equipped with a pressure switch  31  that prevents the opening of both the upper ball valve  21  and lower ball valve  22  if there is a high pressure in the cooking chamber  46 . This safety feature prevents high temperature water from escaping from the cooking chamber  46  during the cooking cycle. 
     There is also a thermocouple  39  attached to the exterior of the cooking chamber  46 . This provides temperature feedback to the PLC. Based on this information, the PLC may add heat to the cooking chamber  46  by opening valve  24  and allowing heated, pressurized water to flow into the cooking chamber  46 . Alternatively, the PLC may reduce the heat in the cooking chamber  46  by opening the vent valve  27  and allowing air, steam and heated water to escape from the cooking chamber  46 . 
     During the time that the food is located in the cooking chamber  46 , it is desirable to agitate the food to promote uniform cooking and minimize the food&#39;s tendency to adhere to itself This may be done while the valve  24  is closed by venting a small amount of pressure through the vent valve  27  that is associated with the cooking chamber  46 . The reduction in pressure will cause the high temperature, pressurized water in the cooking chamber to boil, thereby agitating the food. Further agitation may be provided by briefly reopening the cooking chamber fed valve  24  after the venting step to allow for an influx of heated, pressurized water. This will also restore some of the heat and pressure that was lost during the venting agitation step. The PLC of the present may be pre-programmed to perform these steps periodically, or almost continuously throughout the time that the food is in the cooking chamber  46 . 
     In the preferred embodiment of the present invention, the vent valve  27  is designed to ensure that air, not water, is primarily venting process. As such, the location of the vent valve  27  is preferably towards the top of the cooking chamber  46  so that steam is vented instead of water. Additionally, flange  45  may be a swirl flange that is equipped with a swirl ring  55 . The swirl ring  55 , as shown in FIG. 4, may be equipped with a multiple of slots  104  to provide multiple paths from the cooking chamber  46  to the swirl inlet line  56 . The swirl inlet line  56  leads to vent valve  27  as well as to boiler  10 . The flow of water through swirl inlet line  56  from the boiler  10  may be controlled by a valve  23 . There may also be an o-ring or washer  54  located between the upper flange  45  and the seal plate  44 . The seal plate  44  serves to hold the washer  54  and the swirl ring  55  in position so that a seal is formed; this may be is assisted by an o-ring  54  which may be located between the seal plate  44  and the swirl flange  45 . 
     The multiple slots  104 , which are located towards the top of the cooking chamber  46 , serve several purposes. First, they are sized to prevent food from escaping. Secondly, they help to ensure that steam, and not water, escape through the vent valve  27 . Additionally, as described below, they assist in the cleaning cycle of the invention. 
     The conditioning chamber  38  is located below the cooking chamber  46 . The conditioning chamber  38  has an upper flange  48  and a lower flange  49 . A valve such as a ball valve  22  may be located between the cooking chamber lower flange  47  and the conditioning chamber top flange  48 . There may also be a slide valve assembly  80  coupled to the lower flange  49  that may be opened when it is desired to remove the cooked food from the conditioning chamber. This slide valve assembly  80  may be opened when the operator desires to remove the cooked food from the conditioning chamber, or after a predetermined mount of time has elapsed. As shown in FIG. 3, A strainer  50 , with optional handle  51  and a drip tray  52  may be located under the conditioning chamber  38  to receive the cooked food once the slide valve assembly  80  is opened and the cooked food is removed from the conditioning chamber. 
     Once the food in the cooking chamber  46  has been exposed to the high temperature pressurized water for a sufficient amount of time, it is ready to be transferred to the conditioning chamber  38 . Before transfer, the elevated pressure in the cooking chamber  46  is preferably reduced to by opening the vent valve  27 . This reduced pressure is preferably from 1 to 2 bar. The reduction in pressure reduces the possibility of a high velocity flow that may damage the food being cooked. The lower ball valve  22  may then be opened to allow the food and heated water drop into the conditioning chamber  38 . This movement of the water and food may be caused primarily by gravity. The movement of the water and food may be also caused or facilitated by residual pressure left in the cooking chamber  46  after vent valve  27  has been opened. Such natural movement of the water and food product obviates the need for additional pumps, the action of which may break or otherwise damage the food, to move food between stages. The slide valve assembly  80  at the bottom of the conditioning chamber  38  is preferably closed at the time the lower ball valve  22  is opened. Valve  22  is then closed after the water and food product have passed into the conditioning chamber  38 . 
     The closing of the ball valve  22  isolates the cooking chamber  46  from the conditioning chamber  38 . As such, cooking chamber  46  will be ready to repeat the cooking cycle once the ball valve  22  is closed. 
     If the slide valve assembly  80  was closed at the time the lower ball valve  22  was opened, the conditioning chamber  38  will retain the food in a pool of heated water, and allow the food to further cook and/or absorb water. Alternatively, if a conditioning step is not desired by the operator, the slide valve assembly may remain open at the time the lower ball valve is opened, and the food and water may proceed directly to the strainer. The texture of the food may be affected by time, temperature and agitation. To optimize the conditioning effect, the conditioning chamber  38  is equipped with hot and cold water supplies. The cold water may be supplied by a cold water intake line  26  and may enter the conditioning chamber  38  through the conditioning chamber cold water inlet  58 . The hot water may enter the conditioning chamber  38  through a hot water intake line and valve  25  from the boiler  10  to the hot water inlet  53 . The hot water inlet  53  is preferably located near the bottom of the conditioning chamber  38  so that the blast of heated water will further agitate the cooking and conditioning food. 
     Once the food in the conditioning chamber  38  has been exposed to the heated water for a sufficient amount of time, the slide valve assembly  80  may be opened so that the food can drop into the strainer  50 . A preferred embodiment of the invention includes a safety sensor (not shown) that prevents the slide valve assembly  80  from opening when the strainer  50  is not in place. This prevents the operator of the invention from the burns that may be caused by when the hot food and water spills out. Additionally, the placement of the strainer  50  prohibits the operator from placing their hand in the path of the hot food and water. The strainer  50  may also be retained by a latch assembly  61  (see FIG. 2) that locks the strainer  50  in position and releases only after excess water has drained from the cooked food. 
     Once the latch assembly  61  unlocks, the strainer  50  may be removed, and the contents may be accessible for their intended use (individual servings, large platters, storage, etc.). The empty strainer  50  may then be replaced so that it is ready to receive the next batch of cooked product. When processing batches of food in succession, the cooking chamber  46  and conditioning chamber  38  will both contain product at the same time. To accommodate this, if the length of time the food is in the cooking chamber  46  is shorter than the time that the food is in the conditioning chamber  38 , the operator may either (1) space the input of food into the cooking chamber  46  so that the conditioning chamber  38  is timed to be empty when the food is due to be transferred from the cooking chamber  46  to the conditioning chamber  38  or (2) adjust the length of time of each cycle so that the conditioning chamber  38  cycle is not longer than the cooking chamber  46  cycle. 
     The PLC may be any electronic control device as is known in the industry. It should be capable of reading electrical signals from a variety of sensors, such as pressure switches, position sensors and thermocouples. In a preferred embodiment of the present invention, the PLC is capable of interacting with a touch screen  70  to allow an operator to command the PLC to initiate and perform a cooking sequence. The PLC takes input from such sensors, performs a logic sequence, and generates a series of outputs. These outputs take the form of a display on the touch screen  70  that provides information to the operator. The outputs also include the electrical signals that operate the valves, heaters and motors that are required to execute the cook sequence. 
     In a preferred embodiment of the present invention, the PLC is equipped with modem capacity. This permits remote monitoring of the functions of the invention. The monitoring can be used for billing, inventory control, and diagnostic purposes. 
     The present invention has a cleaning cycle in which high temperature water is passed through the apparatus. During this cycle, valve  23  is opened to allow hot water to flow through the swirl inlet line  56 . This water is directed to swirl ring  55 . The slots  104  in the swirl ring  55  are oriented to direct cleaning water tangentially along the inner wall of the cooking chamber  46 . The high velocity and the centrifugal force of the swirling water on the inside of the cooking chamber  46  enhance the action of the cleaning water. Further, the high temperature pressurized water that is used to wash the apparatus is hot enough to kill bacteria, either in liquid or vapor form. This is a significant improvement over the cleaning methods that are known in the art. 
     The drain line is also regularly cleaned to prevent bacteria build-up. The vent lines that transport high temperature fluid and steam are routed to the drain fitting on the drip tray  52 . This ensures that the drain line is purged with steam every cooking cycle. 
     FIG. 5 illustrates a cross-section of a cooking stack according to an embodiment of the present invention. In this embodiment of the invention, the cooking chamber  46  is located above the conditioning chamber  38 . While the cooking chamber  46  shown is primarily tubular and the conditioning chamber  38  has a bulbous shape, it should be understood that these aspects of the present invention may take any shape that is appropriate for the cooking of food as taught by the present invention. 
     As may be seen in FIG. 5, food may be provided to the cooking chamber  46  through funnel  34 . This funnel may be covered by a top plate  33  to prevent unwanted materials from dropping into the funnel and, consequently, into the cooking chamber  46 . Towards the bottom of the funnel  34 , there is a sliding door  35  that may be opened when it is desired to add food to the cooking chamber  46  at an appropriate point in the cooking cycle. Such opening may be performed by a sliding door actuator  42 . The funnel  34  is mounted on the apparatus at the mounting plate  43 . Upper ball valve  21  is located below the mounting plate  43 . Upper ball valve  21  may be opened by any means as is known in the art, such as upper actuator crank  63 . Upper ball valve motor  71  may be used to open upper ball valve  21 . Below the upper ball valve  21 , the seal plate  44  and cooking chamber o-ring  54 , which provide a seal between the ball valve  21  and the cooking chamber  46 , may be seen. Swirl inlet line  56 , which provides pressurized, heated water, and swirl flange  45  may also be seen in this view of the present invention. 
     Cooking chamber inlet line  57 , through which heated, pressurized water may enter the cooking chamber  46 , is also shown in the view of FIG.  5 . The cooking chamber inlet line  57  is preferably located towards the bottom of the cooking chamber  46  to allow the heated, pressurized water to enter the cooking chamber  46  without subjecting the food to be cooked to unnecessary forces. A cooking chamber lower flange  47  is also located towards the bottom of the cooking chamber. A lower ball valve, through which food and heated water may flow into the conditioning chamber  38 , is located below lower flange  47 . Lower ball valve  21  may be opened by any means as is known in the art, such as lower actuator crank  64 . Lower ball valve  21  is also equipped with ball valve stam  78  and a lower ball valve motor  72 , which may be used to open lower ball valve  21 . 
     The conditioning chamber  38  has an upper flange  48  and a lower flange  49 . There is a cold water inlet line  58  to allow cool water to enter the conditioning chamber  38 , and a hot water inlet line  53  to allow heated water from the boiler  10  to enter the conditioning chamber. Hot water inlet line  53  is preferably located towards the bottom of conditioning chamber  38  so that the addition of heated, pressurized water may be used to agitate or stir the cooking food. 
     As further shown in FIG. 5, in one embodiment of the invention there may be a slide valve assembly  80  coupled to the lower flange  49  that may be opened when it is desired to remove the cooked food from the conditioning chamber. Such slide valve assembly  80  may include a sliding door o-ring  65  to provide an adequate seal between the conditioning chamber  38  and the sliding door plate  73 . The sliding door plate  73  may be supported and guided by a sliding door plate support  74 . The sliding door plate  73  may also be supplied with sliding door rails  66  along which it may slide. A wheel  68  may rotate about an axle  77  to facilitate and guide the movement of the sliding door plate  73 . The slide valve assembly  80  may also have a sliding door plate activator  81  to and a sliding door activator bracket  75 , which served to link the sliding door plate activator  81  to the apparatus. The actuator  81  may pivot around a lead screw  69  at pivot  76 . The sliding door plate  73  may be moved into either an open position or a closed position by the turning of the lead screw  69 . The sliding door actuator  81 , which controls the turning of the lead screw  69  may be manually manipulated to open the slide plate door. Alternatively, the PLC may be programmed to open the sliding door plate  73  when the food has spent sufficient time in the conditioning chamber  38 . There may also be what will be referred to as a cam track  67 , which is a track along which those portions of the present invention that are joined to the sliding door plate  73  may move. 
     While a detailed description of a slide valve assembly  80  has been provided, it should be understood that any configuration that would allow for a controllable opening at the bottom of the conditioning chamber is within the scope of this disclosure. 
     As noted above, a preferred embodiment of the present invention has a cooking stack that is primarily vertical. That is, the cooking chamber  46  is arranged so that it is located substantially above the conditioning chamber  38 . While a large set-up may be suitable in some settings, it may be preferable to limit the height of the present invention so that it is appropriately sized for a larger number of spaces. To this end, it may be preferable to limit the height of the cooking chamber so that it is suitable for cooking food that is no longer than 7.5 inches in length. 
     While the materials of the present invention may be made from any reasonable material as is known in the art, it is preferable that the portions of the present invention that contact food are preferably made from stainless steel. The stainless steel has a tendency to shed food build up after a thorough rinse with water, such as the manner described above.