Patent Publication Number: US-2023148782-A1

Title: Sous vide device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to and is a continuation of U.S. Pat. Application Serial No. 16/636,000, filed on Jan. 31, 2020, which is a national stage entry, filed under 35 U.S.C. § 371, of International Patent Application No. PCT/AU2018/000156, filed on Aug. 29, 2018, which claims the benefit of Australian Patent Application No. 2017903600, filed on Sep. 6, 2017. The contents of the aforementioned U.S. patent application, international patent application, and Australian patent application are incorporated herein by reference in their entireties. 
    
    
     FIELD 
     The invention relates to sous vide devices and more particularly to an immersion style sous vide device. 
     BACKGROUND OF THE INVENTION 
     Sous vide devices can be categorised as being either a bath type or an immersion type device. Bath type sous vide devices have a dedicated cooking vessel or reservoir that is integrated with a recirculating, heated water supply, timers and other features. The immersion type device seeks to provide comparable functionality in a compact form that can be immersed into an ordinary vessel. Because the device can be used with an ordinary pot, it solves storage problems associated with a vessel-sized solution, and also provides a cost advantage to vessel-based solutions. It is therefore favoured in kitchens. 
     The present technology seeks to improve the design and construction of both immersion and bath type sous vide devices. The technology provides performance benefits, ease and versatility of use, and facilities hygiene and maintenance. 
     SUMMARY OF THE INVENTION 
     There is disclosed herein a sous vide device including:
     an outer housing;   a first inner wall located within the housing and enclosing a space;   a second inner wall located in the space and enclosing a first duct, with a second duct being located between the first inner wall and second inner wall, with the first duct having a liquid inlet, and the second duct having a liquid outlet adjacent the liquid inlet, with the first duct being connected to the second duct at a position spaced from the inlet and outlet so as to provide a liquid flow path extending from the inlet to the outlet;   rotatably driven vanes associated with the fluid flow path to cause liquid to flow from the inlet to the outlet;   a motor drivingly connected to the vanes to cause rotation thereof; and   a heater operatively associated with the fluid flow path to heat the liquid passing therealong.   

     Preferably, the heater is mounted on a surface facing the second duct to heat the liquid as liquid passes along the second duct. 
     Preferably, the second inner wall is mounted for rotation about a rotational axis, and is rotatably driven by the motor, with the vanes attached to the second inner wall so as to be rotatably driven thereby. 
     Preferably, the vanes are located adjacent the outlet so as to propel the liquid through the outlet from the second duct. 
     Preferably, the first inner wall is tubular, and the second inner wall is tubular. 
     Preferably, the sous vide device further includes a temperature sensor mounted on the first inner wall and to provide a signal indicative of the temperature of the liquid passing along the second duct. 
     Preferably, the sous vide device further includes a switch operatively associated with the heater to deliver electric power thereto, with the switch being mounted on the first inner wall so as to be at least partly cooled by liquid passing along the second duct. 
     Preferably, the motor is mounted to be remote from the inlet and outlet so as to be positioned adjacent where the first duct communicates with the second duct. 
     Preferably, the vanes are vanes of an impeller. 
     Preferably, the sous vide device further includes a first magnetic coupling rotatably driven by the motor, and a second magnetic coupling driven by the first magnetic coupling and associated with the vanes so as to cause rotation thereof. 
     Preferably, the second duct is annular in configuration and surrounds the first duct. 
     There is further disclosed herein a sous vide device including:
     an outer housing;   a drive wall rotatably mounted in the housing and enclosing a duct that is at least part of a liquid flow path through the device;   a plurality of vanes mounted on the wall so as to be rotatably driven thereby to cause the liquid to pass along the flow path;   a heater to heat the liquid passing along the flow path; and   a motor drivingly coupled to the tubular wall to rotate the tubular wall.   

     Preferably, the sous vide device further includes a first magnetic coupling rotatably driven by the motor, and a second magnetic coupling, rotatably driven by the first magnetic coupling, and fixed to the tubular wall so that rotation of the motor causes rotation of the tubular wall via the first and the second magnetic coupling. 
     Preferably, the vanes are vanes of an impeller. 
     Preferably, the drive wall is a first wall, the duct is a first duct and the sous vide device includes a second wall, with the second wall surrounding the first wall so as to provide a second duct located between the first wall and the second wall that is connected to the first duct so as the first and second ducts provide said fluid flow path. 
     Preferably, the heater is mounted on the second wall. 
     Preferably, the sous vide device further includes a switch operatively associated with the heater to deliver electric power thereto. 
     Preferably, the first duct provides a fluid flow path inlet, and the second duct provides a fluid flow path outlet, adjacent the inlet, with the first duct communicating with the second duct at a position remote from the inlet and outlet, and the vanes are located adjacent the outlet. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the invention be better understood, reference is now made to the following drawing figures in which: 
         FIG.  1    is a perspective view of an immersion type sous vide device; 
         FIG.  1 A  is a perspective view of an immersion type sous vide device; 
         FIG.  2    is a cross-sectional schematic view of the device depicted in  FIG.  1   ; 
         FIG.  3    is an exploded perspective view of a main body, foot and impeller component; 
         FIG.  4    is a cross-sectional view through a main body, impeller and foot; 
         FIG.  4 A  is a perspective view of a heater tube comprising a thick film heater circuit on the dry or external surface of the tube; 
         FIG.  5    is a perspective view of a hybrid (or compound) impeller component; 
         FIG.  6    is a cross-sectional view of an immersion type sous vide device; 
         FIG.  7    is a cross-sectional view of an immersion type sous vide device; 
         FIG.  8    is a bottom plan view of a foot; 
         FIG.  9    is a cross-sectional view through the foot depicted in  FIG.  8   ; 
         FIG.  10    is an exploded perspective of an impeller component showing magnets located within the head; 
         FIG.  11    is a schematic cross-section of an immersion type sous vide device having a removable impeller where the (complex or hybrid) impeller is driven via mechanical coupling to motor through a conventional shaft seal; 
         FIG.  12    is a schematic cross-section of an immersion type sous vide device having a removable impeller, where the (complex or hybrid) impeller is driven via mechanical coupling to motor through a conventional shaft seal; 
         FIG.  13    is a cross-sectional illustration of an immersion type sous vide device having a motor with an elongated shaft and a static partition, where a single axial impeller is driven via mechanical coupling to motor through a conventional shaft seal; 
         FIG.  14    is a schematic cross-section illustrating the integration of the present technology with a dedicated reservoir; 
         FIG.  15    is a schematic cross-section illustrating the integration of the present technology with a dedicated reservoir; 
         FIG.  16    is a perspective view of a sous vide device having remote temperature probes; 
         FIG.  17    is a plan view of a user interface adapted to receive jacks from two different thermal probes; 
         FIG.  18    is a plan view of a user interface adapted to receive jacks from two different thermal probes; 
         FIG.  19    is a plan view of a user interface adapted to receive jacks from two different thermal probes; 
         FIG.  20    is a plan view of a user interface adapted to receive jacks from two different thermal probes; 
         FIG.  21    is a plan view of a user interface adapted to receive jacks from two different thermal probes; 
         FIG.  22    is a plan view of a user interface adapted to receive jacks from two different thermal probes; 
         FIG.  23    is a plan view of a user interface adapted to receive jacks from two different thermal probes; 
         FIG.  24    is a cross-sectional view through an embodiment impeller; 
         FIG.  25    is a cross-sectional view of an embodiment sous vide device; and 
         FIG.  26    is an exploded sectional view of the sous vide device of  FIG.  25   . 
     
    
    
     BEST MODE AND OTHER EMBODIEMENTS OF THE TECHNOLOGY 
     As shown in  FIG.  1   ,  FIG.  1 A  and  FIG.  2   , the present technology may be embodied in an immersion type sous vide device  100 . A device such as this is immersed in a vessel  101 . The device has a flat bottom surface  110  that can rest on the bottom of the vessel  102 . In the alternative and as shown in  FIG.  1 A , a clamp  150  may be provided to attach the device to a pot. The clamp  150  has a collar  151  in which the device  100  can be raised or lowered relative to the collar  151 . A screw tightened or spring loaded clip  152  bears against a lower part  153  of the collar  151 . In the alternative it can be attached to a side wall of the pot  103 . The device  100  has a cylindrical body (outer housing)  104 . The body  104  has a cylindrical and removable foot  105  that functions in this example as both an intake port and an output port. When the device is operating, water is drawn into an axial intake port  107  and is discharged through at least one radially directed output port  106 . As will be explained, the cylindrical main body portion  108  surrounds a cylindrical output flow path that is adjacent a cylindrical heating element and outwardly concentric an intake flow path within it. The flow paths may be reversed in some embodiments by changing the directionality of the impellers. 
     As shown in  FIG.  2   , the tubular heater  201  and a motor driven impeller  202  are controlled by a power control module  203 . By way of example, a multiphase brushless DC motor and control circuit may be used. The power control module  203  also receives inputs from the heater’s over-temperature fuse or sensor  204 , a first temperature sensor  205  that senses the temperature of an incoming water flow and transmits relevant information to the power control module  203 , and a second temperature sensor  206  that measures the temperature of the heating element (for example a cylindrical thick film heater) and transmits this information to the processor  203 . The power control module  203  regulates a triac  207  that is preferably mounted to better dissipate heat by thermally conducting through a surface and or body with circulating water. The power control module  203  regulates the heating element by controlling the firing of the triac  207 . The power control module  203  also regulates the operation of the motor  208  providing the benefit of being able to control the flow rate of water for varied applications. Larger volume vessels can require higher flow rates to satisfactorily mix larger volumes of water, whereas smaller volume or shallowly filled vessels require can benefit from lower flow rates to prevent surface agitation or ‘bundling’ of bagged items. The motor  208  drives the impeller  202 . 
     The power control module  203  receives input commands from a user interface  210 . Conventional user input commands relate to time and temperature profiles, limits or other preferences. The power control module  203  provides information to the user interface through a graphic display  211 . The device has one or more temperature probe input ports  212 . Temperature information from a remote probe may be displayed on the graphic interface  211 . 
       FIG.  3    illustrates the main body tube  108  in relation a magnetically driven impeller  300  assembly and the generally cylindrical foot  301 . In preferred embodiments, the foot  301  and main body  108  removably and rotatably connected to one another and capture between them, the freely rotating impeller  300 . In this example, a neck or coupling area  302  has an external surface  306  that cooperates with a metallic spring type ring  303  internal to the foot  301 . When assembled, the foot’s exterior  301  is flush with the exterior of the main body  108  and its axial location with reference to the main body is established by contact of the upper rim  304  of the foot  301  with a shoulder  305  adjacent to the neck or coupling area  302 . The neck or coupling area  302  may be adapted to couple of engage the foot  301 . In this example, the coupling area  302  defines a groove  323  that aligns with the spring type ring  303  when the main body  108  is coupled to the foot. The spring can be retained by a groove in both the neck and the foot for enabling the body to rotate with respect to the foot while coupled. It will be appreciated that the engagement or coupling may alternatively use threads (e.g. at  306 ) or other means. The foot  301  is adapted to rotate and thereby provide user adjustability of the flow direction of the discharge water path. This is advantageous to optimise circulation and temperature stability to avoid disparate temperature regions within the bath when multiple bagged items are placed within. 
     As shown in  FIG.  3   , the impeller assembly  300  has a head  310  defined by the lower half of the magnetic coupling to the motor, a cylindrical, axial partition  311  an array of radial vanes  202  forming a discharge impeller  320  formed around the lower exterior of the inner tubular wall (inner wall-partition)  311  that encloses a first duct  461 . The base of each vane  202  is integrated with the upper surface  313  of the region of the impeller assembly whose lower surface forms a smoothly curved central intake port  312 . Thus, the same web of material forms the exterior surface of the intake and the inner surface of the discharge area between the individual vanes  202  and the in-current and ex-current flows are produced coaxially, minimizing the required water draft for operation. 
     As shown in  FIG.  4   , the outer tube  400  of the main body  108  contains a dry compartment  460  defined by a terminal ring  401  and having a heater tube (further inner wall)  448 . The ring  401  fits within the lower end of the outer tube  400  and is sealed against it. The ring has a groove  402  that carries a polymeric seal  403 , such as an O-ring type seal. The ring maybe attached to the tube in other ways. The ring forms a neck or a coupling surface  404  that is adapted to fit within the foot  105 . In this example, the foot forms the female portion of a coupling or engagement with the main body  108  and carries a polymeric seal or a circular spring wire  405  in a circumferential groove  406  for this purpose. Other means of attachment are contemplated. A second duct  462  is located between the inner tubular wall  311  and heater tube  448 . 
     The ducts  461  and  462  co-operate to provide a flow path  463  extending from the inlet port  107  to the outlet port  106 . The duct  461  is cylindrical in configuration which the duct  462  is annular and surrounds the first duct  461 . The direction of flow in the duct  461  is opposite the direction of flow in duct  462 . 
     The ring  401  preferably makes flush contact  407  with the upper surface of the foot’s intake port  407 . The ring  401  thus forms a smooth or tapered throat  408  that receives the impeller assembly and related parts  300 . 
     The impeller component  300  is isolated from the electric motor  410  by a sealed barrier or plate  411 . In this example, the plate has a dimple  412 , the underside of which receives an upper most bearing surface protrusion  413  of the impeller  300 . The motor  410  drives one half  414  of a magnetic coupling. An upper portion  415  of the impeller component  300  carries internal magnets and forms the other half of the magnetic coupling arrangement. Thus, no direct contact is made between the motor and the impeller assembly and the motor remains fluidically isolated or environmentally sealed from the impeller  300  and the flow path of the water around it. The ducts  461  and  462  communicate adjacent the motor  410 . 
     In one direction, the axial motion of the impeller assembly  300  is restrained by the contact between the bearing surface  413  and the dimple  412 . In the other direction, the motion is restrained by a hub  416  carried by one or more arms  417  that extends inward from underside  418  of the foot  105 . The hub  416  may have a bearing or bushing  419  for carrying a tip  420  of the impeller component  300 . In preferred embodiments, the outer diameter of the hub  419  is the same as the diameter of the tapered distal tip of the shaft  422 . The tip  420  maybe provided as the terminal end of a longitudinal metal shaft  421  carried along and within all or a part of the longitudinal extent of the impeller shaft  422 . The impeller shaft  422  interconnects the impeller’s head  430  with the array of vanes  202 . The impeller device  300  also has a cylindrical partition  311 . Water drawn into the device travels upwards through the centre of the partition and then reverses direction and flows downward, contacting the cylindrical heated surfaces of the tubular heater and scavenging the heat applied. 
     The cylindrical heater tube  448  interconnects the sealing plate  411  and the ring  401 . In this example, the heater tube  448  carries a heater such as a thick film heating element. The lower end of the heater tube  448  is attached to the inner diameter of the ring  401 . The heater tube is empty, but for the impeller. 
     Cooler water from the vessel is picked-up by the innermost chamber of the hybrid impeller which is defined about the impeller’s shaft  422  and within an inner surface of the cylindrical partition  311 . At the upper terminus of the impeller, there is optionally a flow diverter shape formed on the underside of the lower magnetic coupling body  442 . This flow diverter advantageously changes the collective vector of the incoming water from upward to downward, permitting the water to scavenge heat that is generated by the heated tube  448 . The now heated water flowing downward outside the tubular partition  311  changes its collective vector from axial to radial direction by action of the multiple rotating vanes (202). The flow paths may be reversed in some embodiments by changing the directionality of rotation and vanes. 
     The radially displaced discharge flow is carried between the wall of the tubular heater or heated tube  448  and the outer surface of the partition  311 . The partition tube  311  and the impeller shaft  422  are attached by legs which are in one embodiment comprised of the plurality of axial impeller vanes  450 . 
     The underside of the foot is formed by the flared or tapered, intake throat area  418 , blending smoothly into a diameter that is defined by the inside surfaces  445  of the projections  446  that elevate the intake port from the bottom surface of a pot should it be resting on one. Elevated scallops  447  in the bottom edge of the foot allow the cooler water from the bottom of the vessel to be entrained into the upward flow created by the central axial impeller  450  even when the device is resting flat against the bottom of a pot. 
     As shown in the example  FIG.  4 A , the thick film heating element  440  is formed directly on to or applied to a cylindrical heater tube  501 . Contact points  502  for the heating elements circuit are contained within the dry compartment adjacent and concentric to the outer tube. It will be evident to one skilled in the art that other types of heaters may be used to heat the cylindrical heater tube  501 . 
     As shown in  FIG.  5   , the impeller component  300  may have a second set of impeller vanes  450  that interconnect the hub  416  with the cylindrical partition  311 . In this example three (3) fan or propeller-like blades  502  assist in pumping liquid into the partition  311  when the impeller is rotated. Three propeller vanes are depicted however other numbers of propeller vanes can be substituted. The vanes  502  are formed around the impeller shaft adjacent to the bearing or tip  420 . The portion of the shaft  422  between the vanes  502  and the tip  420  is preferably tapered  503 . 
     As shown in  FIG.  6   , the discharge port  601  is in the form of one or more circumferentially elongated openings, in one embodiment having rounded ends. The port  602  is adjacent to the tips  603  of the discharge vanes  604  in the impeller component  300 . 
     In the example of  FIG.  7   , the upper surface of the impeller component  300  forms a recess  701 . In one embodiment the recess is formed into an engineering polymer or other material adapted to receive a locating pin or stub shaft  702 . The shaft  702  is preferably formed on to or attached to a sealed plate or component  703  that defines the dry compartment  704  between the heater tube  705  and the main body’s outer tube  706 . 
     As shown in  FIG.  8   , in one embodiment the circular foot  800  has integral and curved supporting legs  801  that extend from the intake throat area  802  to the central hub  803 . The legs  801  are static with respect to the flow and are therefore preferably shaped and tapered to minimise hydrodynamic drag. 
     As shown in  FIG.  9   , the coupling between the main body and the foot  900  maybe achieved by way of a circular spring wire  901  carried by a groove  902  formed on an interior surface of the foot. The wire  901  has a flat spot  903  or other feature that either creates friction or engages a cooperating groove formed on the neck  302  of the main body  108 . 
     As shown in  FIG.  10   , the impeller component  300  has a head  1000  within which is located a circular array of magnets  1001 . In this example, the magnets are arranged to alternate between north and south poles facing upward. The cooperating array of magnets associated with the device’s motor is similarly arranged so as to optimise the centering and magnetic coupling relationship between the two coupling halves. The magnets may be moulded into the head, placed into the head and sealed with an epoxy or other sealing means, or retained below a separate and sealed cap  1002 . The cap has a central opening  1003  so that the upper bearing  1004  is not interfered with but so that the separator plate or bulkhead  411  is continuously washed by incoming water permitting the incoming water temperature to be accurately thermally monitored. 
     As shown in  FIG.  11   , the impeller component  300  is easily removed by disconnecting the foot  1100  from the main body  108 . In this example, cooperating threads  1101  are formed on the sealing ring  1102  and the foot  1100 . In this example, the impeller component  300  is driven by a first coupling component  1103  that is attached to the shaft of the motor  1104 . The other half of the coupling arrangement  1105  is formed as a recess in the impeller components head  1106 . In this embodiment a circumferential seal  1107  around the motor’s shaft fluidically isolates the motor from the flow of fluid around the impeller. 
     As shown in  FIG.  12   , one embodiment of the device’s motor  1200  may have an elongated, flatted or otherwise coupling-enhanced shaft  1201  to permit positive rotation of the impeller. In this example, the shaft extends from approximately the upper edge  1202  of the partition tube  1203  to a separable female coupling  1204  located just above the legs or vanes  1205  that connect the partition  1203  to the hub  1206 . In preferred embodiments, the legs or vanes  1205  are located at a lower portion of the partition tube  1203 . In this example, the foot  1207  carries a first part  1208  of bayonet coupling and that ring  1209  carries a second part  1210  of a bayonet coupling by which the foot and that main body are interconnected. In this example, the heater tube  1211  has a circumferential flange  1212  around the lower end. The flange is affixed to the ring  1209  within an array of axial fasteners  1213 . In this example two (2) circumferential polymeric seals  1214  prevent the ingress of liquid into the dry compartment  1215 . In the example of  FIG.  12   , the impeller lacks a head. Optionally, a flow diverter  1220  is fastened to an upper end of the heater tube  1211 . The flow diverter preferably has a half-toroid shape. It is appreciated the flow diverter may comprise a different shape and be integral with the upper end of the heater tube  1211 . The central part of the diverter carries a circumferential seal  1221  through which passes the elongated shaft  1201 . The diverter assists with a low friction change of direction, folding or vector reversal of the flow  1230  as the flow is directed from an upward motion inside the partition tube to a downward motion between the partition tube  1203  and the heater tube  1211 . 
     In the example of  FIG.  13   , the partition tube  1300  is static. It is attached to the foot  1301 . The upper end  1302  of the partition tube sits adjacent to or within a half-toroidal flow diverter  1303 , the centre of which carries one or more seals  1304  for isolating the motor from the fluid flow. The motor’s elongated shaft  1305  terminates in a coupling section  1306  that removably carries an impeller  1307 . The foot  1301  has a flexible upper rim  1308  that receives the lower end of the main body  1309 . The lower end of the main body  1309  has one or more individual or circumferential protrusions  1310  that sit within one or more pockets or a circumferential groove  1311  formed around the inside surface of the rim  1308 . In some embodiments, the rim  1308  comprises one or more flexible arms  1320 , each having a protruding lip  1321 . The arms flex to engage and disengage a continuous protrusion  1310  around the lower end of the main body  1309 . 
     Although previous examples have disclosed the utilisation of a cylindrical thin film heater to create an elongated and heated flow path, heat may be applied to the heater tube using conventional heating elements  1315  that are wound about or otherwise applied to an exterior of the heater tube  1330  or even function as a heated replacement for the separator tube. 
     As shown in  FIG.  14   , a device fabricated in accordance with the previous disclosure for stand-alone use  1400  may be integrated with or attached to a dedicated reservoir  1401 . Liquid in the reservoir flows into the partition tube  1402  through the intake  1403 . The flow is discharged through the discharge port  1404 . As suggested by  FIG.  14   , the main body  1400  is rigidly attached to or affixed to the reservoir while the foot  1405  is removable in the ways previously described. This allows the impeller component  1410  to be easily removed for cleaning or replacement. In the example of  FIG.  14   , the device extends through an opening  1430  in a bottom surface of the reservoir. In the example of  FIG.  15   , the device is retained within an opening  1501  in a sidewall  1502  of the reservoir  1503 . 
     As shown in  FIG.  16   , the head of the device  1600  may have one, two or more receptacles  1601  for receiving the plug or plugs  1602  associated with a thermal probe  1603 . In the example of  FIG.  16   , the receptacles  1601  are located on opposite lateral sides of the user interface  1603 . 
     As shown in  FIG.  17   , the receptacles  1700  may be located on the same side of the user interface  1702 . In this example, the interface displays cooking time information  1703 , a measured temperature or average of same  1704  and a target temperature  1705 . 
     As shown in  FIG.  18   , when only one of two thermal probes  1801  is attached to the head, a temperature display for that probe is created in an area  1802  of the graphic interface adjacent to the subject probe  1801 . 
     As shown in  FIG.  19   , when both probes are inserted into their respective receptacles, two different temperature displays are created  1901 ,  1902  each in an area of the graphic display  1903  that is adjacent to the insertion location of the respective probes  1904 ,  1905 . The time graphics are moved to the opposing display side to the active probe receptacles. 
     As shown in  FIG.  20   , the device may display temperature information  2000  generated from temperature probes located within the device. Because no external probe  2001  is connected, no information regarding the external probes is displayed. In the example of  FIG.  21   , a single display  2100  is generated adjacent to the receptacle opening  2101  that has received an operating probe  2102 . In the example of  FIG.  22   , both remote probes  2200 ,  2201  are inserted into their receptacles  2202 ,  2203 . The processor upon receiving information from the receptacles  2202 ,  2203  generates a separate display of temperature for each probe  2204 ,  2205 . Preferably, the displays  2204 ,  2205  are directly adjacent to the appropriate receptacle  2202 ,  2203 . In preferred embodiments, the graphics will re-arrange or be modified when the probe is introduced to the receptacle. For example, the temperature sensed by the probe may be displayed larger and more prominent than the bath temperature. 
     As shown in  FIG.  23   , the receptacles  2300 ,  2301  for the temperature probe jack  2302  may be located on an upper surface  2303  of the head  2304 . As suggested above, upon noting the presence the jack inserted into a receptacle, the processor causes a temperature display  2305  adjacent to the corresponding probe. In preferred embodiments, a display  2305  is only created by the processor when a probe is inserted through a receptacle. 
       FIG.  24    teaches an embodiment impeller assembly  2400  having a head  310  that defines a lower half of the magnetic coupling to a motor, a cylindrical axial partition  311  that forms a discharge impeller  320  about the lower exterior of the partition. Each vane of the impeller is integrated with a surface  313  such that the under-side surface forms a smoothly curved central intake port  312 . In-current and ex-current flows are produced coaxially, which can reduce the required water draft for operation. The impeller assembly  2400  may have a second set of impeller vanes  450  that interconnect the hub  416  with the cylindrical partition  311 . In this embodiment, by way of example only, a first set of fan or propeller-like vanes  502  assist in drawing or pumping liquid into the partition  311  when the impeller is rotated. The first set of vanes  502  are formed around the impeller shaft adjacent to the bearing or tip  420 . In this embodiment, by way of example only, a second set of three (3) fan or propeller-like vanes  2402  are provided about the top of the partition  311  to assist in drawing or pumping liquid into the partition  311  when the impeller is rotated. It will be appreciated that, while three propeller vanes are depicted, other numbers of propeller vanes can be substituted. 
       FIG.  25    and  FIG.  26   , teach use of a stationary disc element  2500  with an aperture  2502  that, in use, can reduce the vortex generated beneath the spinning impeller of the sous vide device. This de-vortexer element  2500  provides a stationary concentric disc with an aperture, which is supported by the foot  301  and closely spaced under the rotating impeller. This reduces an undesirable vortex forming below the axial intake. The underside or lower surface  312  of the impeller  320  is generally disc-shaped, having a smooth transition to the interior of the cylindrical partition  311 . The de-vortexer element  2500  presents a substantially stationary underside for the sous vide device, with an aperture that exposes the fluid to the intake propeller vanes  502 . The underside or lower surface  2504  of de-vortexer element  2500  can be contoured (e.g. at  2506 ) to present a curved smooth transition to the intake aperture. The technology provides an immersion type sous vide cooking device that utilises a heated element in contact with a flow path. The heated element is described as a tubular heater or heated volute. The flow path enters and exits the device from the same end, by means of a hybrid or compound impeller. The prior art devices have separate intake and output ports, located in substantially different or opposing regions of the device. The present sous vide cooking device positions intake and output ports about the distal end of the device, thereby creating two distinct advantages: the device requires a less complex sealing of internal components; and the device is able to work in shallow water to prepare custards, eggs and aspics and the like. 
     In some embodiments a flow path through a sous vide device has a folded or concentric flow path. It will be appreciated that, this folded path is enabled by the axial propeller which is submersed even if the water level is very low. It is this first propeller that enables the priming of the concentric path. It has a folded or concentric flow path in order to move incurrent and excurrent paths closer and enabling use in substantially shallower vessels. By way of example only, an embodiment sous vide cooking device may operate in 12.5 mm of water. 
     Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms. 
     The technology provides an immersion type sous vide cooking device that utilises a tubular heater. In the present embodiments the tubular heater includes a heater in contact with a flow path. The flow path enters and exits the heater from the same end by means of a hybrid (or compound) impeller. 
     As used herein, unless otherwise specified, the use of the ordinal adjectives “first”, “second”, “third”, etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner. 
     Reference throughout this specification to “one embodiment” or “an embodiment” or “example” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an example” in various places throughout this specification are not necessarily all referring to the same embodiment or example, but may. 
     Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments. 
     Similarly it should be appreciated that in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Any claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this invention. 
     Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification discussions utilizing terms such as “processing,” “computing,” “calculating,” “determining” or the like, refer to the action and/or processes of a microprocessor, controller or computing system, or similar electronic computing or signal processing device, that manipulates and/or transforms data. 
     Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination. 
     Thus, while there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the scope of the invention, and it is intended to claim all such changes and modifications as fall within the scope of the invention. 
     While the present invention has been disclosed with reference to particular details of construction, these should be understood as having been provided by way of example and not as limitations to the scope of the invention.