Abstract:
A sleeve ( 50 ) for forced immersion of an article including a tubular body ( 52 ) defining an article travel passage, and at least one fluid inlet ( 58 ) for establishing an article drive stream. The passage defined by the body is generally tubular. The sleeve has means ( 58, 60 ) for establishing a helical stream of liquid inside the passage flowing at the periphery of the passage. The apparatus is applicable to filling a container with fruit.

Description:
This application is a 371 of PCT/FR/01/01372 filed May 4, 2001. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to a sleeve for forced immersion of an article such as a fruit or a vegetable into a basin filled with water, the sleeve comprising a body defining an article travel passage and at least one inlet for a fluid for setting up an article drive stream. 
   Installations for grading and packaging fruit or vegetables are known. Such an installation comprises a conveyor for transporting fruits individually, each in its own cell. The conveyor passes through a station for evaluating the caliber of each fruit and then passes over a set of temporary storage basins, with each basin being assigned to fruits of a common caliber. Each fruit is ejected from the conveyor into the basin corresponding to its caliber. 
   Fruits having the same caliber are stored temporarily in a basin and are subsequently conveyed by a collector channel to a container-filling unit. Such containers are formed by rectangular cases having open top faces. The content of such a container is approximately 1 cubic meter (m 3 ) and such containers are sometimes referred to by the name “palox”. The walls of such containers are perforated. 
   In the filling station, the containers are immersed in a basin full of water and the fruits floating on the surface of the basin are immersed inside the container under the action of a flow of water established in the basin. 
   More precisely, while immersed in the basin of the filling station, the container is covered by a cover having a loading opening. This opening is fitted with a chute for guiding fruits into the inside of the container. The chute generally defines a bend having an open end disposed facing the loading opening in the cover and an opposite end defining a fruit inlet, said inlet extending in a generally vertical plane. The top end of the inlet of the chute is situated above the surface of the water in the basin in which the container is immersed. 
   In order to ensure that articles are immersed, a very fast flow of water is established between the top portion of the basin and its bottom portion. For this purpose, a pump delivering a flow of about 600 cubic meters per hour (m 3 /h) has its inlet connected to the vicinity of the bottom of the basin. The outlet from the pump is connected, for example, to the upstream ends of the temporary fruit-storage basins that are provided at the outlet from the conveyor. 
   The water stream established by the pump circulates from the temporary storage basins to the container-filling basin, flowing along the length of the collector channel. This stream causes fruit to be displaced towards the chute. 
   The water which is sucked into the bottom of the basin and which circulates through the perforated container sets up stream to drive fruits through the chute. 
   The fruits entrained in this way by the stream are caused to pass through the chute and through the cover. They are then retained inside the container by the cover. 
   It will be understood that such an installation for immersing fruits requires a pump to be used that has a very high delivery rate. 
   SUMMARY OF THE INVENTION 
   An object of the invention is thus to provide means for forced immersion of an article, which means make it possible to use a pump having a smaller delivery rate. 
   To this end, the invention provides a sleeve for forced immersion of an article, the sleeve being characterized in that said passage defined by the body is generally tubular and in that the sleeve has means for establishing, in said passage, a helical stream of liquid flowing at the periphery of said passage. 
   In particular embodiments of the invention, the sleeve comprises one or more of the following characteristics:
         said means for establishing the helical stream of liquid comprise at least one injection nozzle forming the liquid inlet and opening out substantially tangentially to the inside of the tubular body, the axis of the injection nozzle at its open end being angularly offset relative to the transverse plane of said passage taken at the open end of the injection nozzle;   the sleeve has at least two nozzles regularly distributed around a circumference of said passage;   the body has a generally tubular outer envelope defining part of said passage, the or each injection nozzle opening out through said envelope, and said means for establishing the helical liquid stream comprise a tubular skirt disposed inside the envelope facing the region into which the or each injection nozzle opens out, which skirt extends over a fraction only of the length of the envelope and defines an article guide duct therein, said skirt co-operating with the envelope to define an annular space in which the helical liquid stream travels, which annular space opens out into said passage at one end; and   the sleeve includes a helical guide disposed in said annular space between the outer envelope and the skirt.       

   The invention also provides equipment for forced immersion of an article, the equipment comprising an immersion sleeve as described above and a pump whose outlet is connected to the or each fluid inlet of the sleeve, which pump has a delivery rate lying in the range 20 m 3 /h to 100 m 3 /h. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood on reading the following description given purely by way of example and made with reference to the accompanying drawings, in which: 
       FIG. 1  is a diagrammatic plan view of a first embodiment of a grading installation including a sleeve of the invention for forced immersion of articles; 
       FIG. 2  is a longitudinal section view of the means for temporary storage of articles implanted in the installation of  FIG. 1 ; 
       FIG. 3  is a perspective view of the sleeve for immersing articles in the temporary storage means of  FIG. 2 ; 
       FIGS. 4 and 5  are views analogous to the view of  FIG. 2 , showing successive operating stages of the storage means; 
       FIG. 6  is a longitudinal section view of a variant embodiment of the temporary article-storage means suitable for including in the installation of  FIG. 1 ; 
       FIG. 7  is a diagrammatic plan view of a second embodiment of a grading installation; 
       FIGS. 8 and 9  are respectively a longitudinal section view and a plan view of means for temporarily storing articles as used in the installation of  FIG. 7 ; and 
       FIG. 10  is a longitudinal section view of a variant embodiment of the means for temporarily storing articles and suitable for being included in the installation of FIG.  7 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The fruit-grading installation shown in  FIG. 1  comprises a fruit-transporting conveyor  12  enabling fruits to be transported individually in cells. At the inlet to the conveyor  12  there is provided a conveyor-loading station  14  enabling fruits for grading to be received in bulk and serving to put the fruits successively in respective cells. 
   Downstream from the loading station  14  there is a station  16  for evaluating the caliber of each fruit traveling on the conveyor. By way of example, this station includes scales or a camera for observing each fruit. The station  16  is connected to a data processor unit  18 . 
   Downstream from the station  16 , the conveyor  12  travels transversely over a set of collector basins  20  filled with water. These basins constitute zones for storing fruit temporarily as a function of their caliber. 
   For each basin, there is provided means  22  for ejecting a fruit traveling on the conveyor. Each ejection means enables a fruit to be dropped into the basin  20  corresponding to its caliber. The ejection means  22  are connected to the data processor unit  18  to be controlled individually thereby. 
   In the invention, each collector basin  20  is fitted with means  24  for temporarily storing fruits in a plurality of superposed layers. These means are described in greater detail with reference to  FIGS. 2  to  5 . 
   Each collector basin  20  is connected at a downstream end to a collector channel  26  for conveying fruit to a container-filling station  28  disposed at one end of the channel  26 . 
   In conventional manner, the filler station  28  has means for bringing in empty containers, means for introducing the fruits brought in by the channel  26  to the inside of the containers, and means for removing filled containers. 
   Each basin  20 , one of which is shown on a larger scale in  FIGS. 2 ,  4 , and  5 , may have a depth of one meter, for example, a length of three meters, and a width of one and a half meters. The basins  20  are installed side by side along the length of the conveyor  12  with their long directions extending perpendicularly to the travel direction of the conveyor. 
   As shown in  FIG. 2 , at an upstream end, each basin  20  has a shallow region constituting a zone  32  for receiving fruits coming from the conveyor  12 . A fruit-guiding ramp  33  extends in part over the zone  32 . 
   At its opposite or downstream end, the basin presents a channel  34  for connection with the collector channel  26 . The channel  34  is likewise shallow. A gate  36  closes the channel  34  so as to allow the basin  20  to be isolated from the channel  26 . The gate is controlled by the data processor unit  18 . 
   The temporary storage means  24  comprise firstly a set of immersed vertical walls forming a closed outline  38  defining a space for storing fruits temporarily in a plurality of superposed layers, and secondly means  40  for forced immersion of each fruit coming from the conveyor  12  into the closed space defined by the closed outline  38 . 
   In the embodiment shown, the closed outline  38  is defined by two parallel side walls  42  of the basin and by two moving panels  44 A and  44 B extending parallel to each other and transversely to the side walls  42 . The panel  44 A is initially placed in the downstream region of the basin while the panel  44 B extends in its middle region. The panels  44 A and  44 B extend transversely to the length of the basin  20 . 
   The panels  44 A and  44 B are carried by a loop mounted to move around four guide gears  48  under the control of drive means  49 . The loop  46  is placed above the basin  20  and travels along the length of the basin. The panels  44 A and  44 B are associated with a third panel  44 C carried by the loop. The three panels  44 A,  44 B, and  44 C are regularly spaced apart along the length of the loop  46 . They are separated by intervals of about one meter. The panels are hinged to the loop  46  and they are maintained substantially vertical under the action of their own weight. The loop  46  has a bottom strand extending over about half of the length of the basin  20 , and a top return strand extending above the bottom strand. 
   The panels  44 A and  44 B as supported in this way by the loop  46  are partially immersed in the basin  20 . Their bottom ends are spaced apart from the bottom of the basin so as to define a gap through which fruits can pass. 
   The means  40  for forced immersion of fruits comprise an inclined fruit-guiding sleeve  50  having an inlet end extending in the fruit-reception zone  32  and an opposite, outlet end directed towards the bottom of the basin and opening out beneath the level of the bottom end of the panel  44 A. 
   The fruit-immersion sleeve  50  is shown on its own in FIG.  3 . It comprises a rectilinear outside tube  52  forming an envelope within which there is disposed, in its upstream portion, a skirt constituted by a tube  54  of smaller diameter. The tube  54  extends along substantially half the length of the outside tube  52 . The lengths of the tubes  52  and  54  are respectively 500 millimeters (mm) and 250 mm. Their outside diameters are respectively 168 mm and 139 mm. The tubes  52  and  54  are coaxial and between them they define an annular space  56  having a width of about 12 mm. 
   At the inlet end of the sleeve, the annular space  56  is closed by a washer  57  welded between the ends of the tubes  52  and  54 . 
   At least one nozzle  58  for admitting water under pressure opens out into the annular space  56  by passing through the outer tube  52 . The or each nozzle is disposed in the vicinity of the inlet end of the sleeve. 
   When a plurality of nozzles are present, they are regularly distributed around a common circumference of the outer tube  52 . 
   In the embodiment shown, the nozzle  58  opens out substantially tangentially to the outer tube  52  and relative to the axis of the sleeve it defines a non-zero angle, with the outlet from the nozzle being directed towards the outlet end of the sleeve. The angle defined by the nozzle  58  relative to the transverse plane of the tube advantageously lies in the range 10° to 120°, and is preferably 45°, for example. The diameter of the nozzle is about one and a quarter inches, i.e. about 3.175 centimeters (cm). 
   Advantageously, a helically-shaped guide wire bar is disposed in the annular space  56 . It bears against both tubes  52  and  54  and serves to guide the stream of fluid coming from the nozzle  58  to follow a helical path. The bar  60  terminates at the end of the inner tube  54 . The helical pitch defined by the bar  60  can be 120 mm, for example. Thus, the angle of inclination of the bar  60  relative to the axis of the tube is identical to that of the axis of the nozzle  58  at its open end. 
   The storage means further comprise a pump  64  whose inlet is connected to a water admission tapping point  66  installed in the vicinity of the bottom of the basin. Three water delivery ducts are connected to the outlet of the pump  64 . 
   A first duct  68  emerges into the bottom of the fruit reception zone  32  behind a vertical wall  70  provided with a horizontal row of nozzles  72  serving to diffuse the water. These nozzles extend substantially level with the surface of the water in the basin  20 . 
   A second duct  74  conveys the water to the bottom of the basin in the fruit reception zone  32 . It opens out between the partition  70  and the inlet to the sleeve  50 . 
   Finally, a third duct  76  is connected to the nozzle  58  of the sleeve for forced immersion of the fruits. The pump is such that the flow rate through the nozzle  58  lies in the range 20 m 3 /h to 100 m 3 /h, and preferably in the range 20 m 3 /h to 40 m 3 /h. 
   An immersed pump  80  is also placed above the sleeve  50 . It sets up a flow of water in the basin  20  flowing round a closed circuit going from upstream to downstream on the surface, i.e. from the zone  32  to the connection channel  34 . 
   The installation shown in  FIGS. 1  to  5  operates as follows. 
   Fruits received in bulk in the station  14  are placed individually in cells. The caliber of each fruit is evaluated in the unit  16 . As a function of the caliber allocated thereto, each fruit is ejected over one of the reception zones  32  of a water-filled basin that corresponds to said caliber. The fruit is then guided to the reception region  32  by the ramp  33 . 
   Initially, the loop  46  of the temporary storage means is placed in a position such that two panels  44 A and  44 B are partially immersed and co-operate with the side walls  42  of the basin to define a closed space for receiving fruits. 
   Under the action of the water circulation set up by the pump  64 , the fruits are guided to the sleeve  50 . 
   The water under pressure delivered to the sleeve  50  from the nozzle  58  enters the annular space  56  with a non-zero angle of incidence relative to the transverse plane. In addition, its path curves on coming into contact with the cylindrical wall of the outer tube  52 . Thus, a helical stream is created inside the sleeve  50  along its outside wall. This stream is directed towards the fruit outlet end. 
   Fruits are sucked into the sleeve  50  by the Venturi effect under the action of the helical stream established at the periphery of the outer tube. The fruits are then conveyed through the sleeve to the bottom end thereof from which the fruits are released into the water of the basin at a depth that is deeper than the bottom end of the panel  44 A. 
   The ejection of fruits from the sleeve  50  and the entry of fruits into the mass of water in the basin  20  are facilitated by the helical stream formed at the outlet from the sleeve, this stream sets up a corkscrew effect that prevents the fruits from coming into abutment against the mass of water. The helical stream set up in the sleeve  50  enables the flow rate of driving water stream needed to immerse one fruit to be relatively small, thereby limiting the capacity needed from the pump  64 . 
   After being expelled from the sleeve  50 , the fruits rise towards the surface since the density of the fruits is less than that of water. Since the fruits are released beneath the closed outline  38 , they are confined within the closed space defined by said outline. 
   As more and more fruits arrive, as shown in  FIG. 4 , the fruits accumulate inside the closed outline  38  and occupy a plurality of layers. The fruits are simultaneously entrained towards the downstream panel  44 B under drive from the stream set up by the immersed pump  80  placed behind the upstream panel  44 A. 
   As soon as the number of fruits introduced between the panels  44 A and  44 B corresponds to the number of fruits that can be contained in a container, the loop  46  is set into motion as shown in  FIG. 5 , causing the downstream panel  44 B to be retracted, being lifted towards the return path, while the upstream panel  44 A pushes the fruits towards the outlet panel  34 . Simultaneously, the panel  44 A constitutes a barrier for retaining any fruits that continue to be delivered by the forced immersion means  40 . The panel  44 A is brought into the position previously occupied by the panel  44 B, with the initial position of the panel  44 A now being occupied by the third panel  44 C which was initially on the return path of the loop. The newly-positioned panels thus define a new closed space for receiving fruits. The above-described cycle is started over. 
   The fruits released by the temporary storage means are then taken by the channel  26  to the container-filling station  28 . 
   It will be understood that the installation descried above makes it possible for each caliber of fruit to have a temporary storage zone for calibrated fruits while considerably reducing the total area occupied by the installation. Each temporary storage means occupies a small amount of floor space because the fruits are stored in a plurality of layers. 
     FIG. 6  shows a variant embodiment of the temporary storage means suitable for use in the installation of FIG.  1 . 
   In this variant embodiment, the vessel  20  is split into two temporary accumulation regions  102  and  104  of substantially identical volumes, by means of a perforated transverse wall  106 . The first region  102  is situated immediately downstream from the fruit reception zone  32 . A forced immersion sleeve  108  whose inlet end is disposed in the fruit reception zone  32  connects the zone  32  to the accumulation region  102 . The outlet end of the sleeve points towards the bottom of the vessel  20  and extends to a depth that enables fruit to accumulate in a plurality of layers. A vertical partition  110  is provided over the outlet end of the sleeve  108 . 
   A second sleeve  112  for forced immersion of fruits is provided through the intermediate partition  106 . The inlet end of this sleeve is placed in the vicinity of the surface of the water contained in the accumulation region  102 . Its outlet end is placed in the region  104 . It points towards the bottom of the vessel and is spaced apart from the level of the liquid. 
   The two sleeves  108  and  112  for forced immersion of fruit are identical to the sleeve  50  of FIG.  3 . They are fed by a pump  114  taking water from the basin  20  and reinjecting it through the sleeves, and also through nozzles provided in the fruit reception zone  32 . 
   Finally, a removable panel  116  is mounted facing the inlet end of the second sleeve  112 . By way of example, the panel  116  can be slid in a vertical direction between a position in which it closes off the inlet to the sleeve  112 , and a position in which it is retracted above the level of the water so that the fruits are freed to engage in the sleeve  112 . The panel  116  thus forms a guillotine. 
   In this embodiment, the panel  116  is initially in its position for closing off the inlet to the sleeve  112 . 
   The fruits arriving from the conveyor and dropping into the reception zone  32  are immersed by the sleeve  112  and are released at depth in the first accumulation region  102  beneath the closed space defined by the side walls of the basin  20  and the walls  110  and  116 . 
   As fruits are ejected from the sleeve  108  they accumulate in a plurality of layers between the walls  110  and  116 . Once a quantity of fruits sufficient for filling a container has accumulated in the region  102 , the panel  116  is raised so that the fruits present in this temporary accumulation region are sucked progressively through the second sleeve  112  and transferred into the accumulation region  114  where they likewise take up positions in a plurality of superposed layers. 
   For loading into a container, the fruits contained in the accumulation region  104  are subsequently transferred by the collector channel  26  and they are taken to the loading station  28 . 
   With such temporary storage means, the total area of the installation is likewise small since the fruits are stored in a plurality of thicknesses. 
     FIG. 7  shows a variant embodiment of the installation of the invention. 
   In this embodiment, elements that are identical or analogous to those of the embodiments in the preceding figures are designated by the same reference numerals. 
   As shown in  FIG. 7 , the variant embodiment of the installation does not have a collector channel  26  for transferring fruits, nor does it have a common unit for loading fruits into containers. 
   Nevertheless, for each caliber of fruit, it does comprise a basin  20  having means  200  for temporarily storing fruits in a plurality of superposed layers. As shown in  FIGS. 8 and 9 , these means comprise means for directly loading fruits in a plurality of layers into the inside of an immersed container. 
   For this purpose, the means  200  comprise a spiral-shaped horizontal channel  202  having the fruits coming from the conveyor  12  received in one end thereof and having a forced immersion sleeve  204  identical to the sleeve  50  of  FIG. 3  installed at its other end. 
   A container  206  is immersed beneath the sleeve  204  in the basin  20 . Such a container has an open top face. 
   In the vessel  20 , there is placed a path  210  on which the container  206  can run and be supported. This path comprises a succession of rollers extending parallel to one another. The path  210  presents a plane region  214  for supporting the container beneath the sleeve  204  and a ramp-forming inclined region enabling an empty container to be immersed and enabling a full container to be extracted from the basin. The position of the path  210  is defined in such a manner that the open face of the container lies immediately beneath the bottom of the channel  202 . 
   A pump  218  having a suction inlet drawing from the basin  20  has its delivery outlet connected firstly to the end of the spiral-shaped channel  202  in which the fruits are received, and secondly to the sleeve  204  in order to feed it with water. 
   In this embodiment, the closed outline defining the fruit-reception space is defined by the four side walls of the container  206 . 
   It will be understood that in this embodiment, as in the preceding embodiment, the fruits from the conveyor  12  all having the same caliber are taken to the sleeve  204  by the channel  202 . The fruits are then immersed and released at the bottom of the case  206  by the sleeve  204 . On rising, the fruits accumulate inside the case  206 , occupying a plurality of superposed layers. The bottom of the channel  202  thus forms a barrier preventing the fruits from escaping from the container  206 . 
   When a container is full, it is extracted from the basin and replaced by an empty container. 
   In this embodiment likewise, temporarily storing caliber-graded fruits in a plurality of superposed layers makes it possible to reduce considerably the area occupied by each of the basins, and thus the total area occupied by the installation. 
     FIG. 10  shows a variant embodiment of the temporary storage means suitable for being installed at each conveyor outlet  12  in the  FIG. 7  installation. 
   In this embodiment, a water-filled basin  300  is adapted to receive a container  302  for transporting graded fruits. The main portion of the basin is of sufficient depth to enable the container  302  to be fully immersed. 
   Moving equipment  304  is mounted so as to be displaceable relative to the basin between a container-filling position shown in  FIG. 10  in which it is immersed, and a retracted position in which the container is retracted to above the level of the basin  300 . This moving equipment is vertically displaceable. It comprises means  307  for supporting a container and a horizontal plate  306  suitable for forming a cover for closing off the container  302  whose top end is normally open. This cover  306  has a sleeve  308  passing therethrough for forced immersion of fruits inside the container  302 . This sleeve is identical to the sleeve shown in FIG.  3 . The sleeve  308  is fed from a pump  310  whose inlet takes water from the vessel  300 . 
   The vessel  300  presents a region of smaller thickness  320  for receiving fruits from the conveyor  12 . The region  320  has a moving shutter partition  322  placed at its end that opens out into the main portion of the vessel that is suitable for receiving a container  302 . 
   In addition, an overflow  324  formed by a generally vertical tube  326  passes through the vessel  300 . A top end  328  defines the height of the liquid surface contained in the vessel  300 . The bottom end  330  of the tube opens out into a buffer vessel  332  disposed beneath the region  320  of the vessel. The bottom of the buffer vessel  332  is connected to a pump  334  whose outlet is connected to one end of the region  320  of the vessel. 
   In this embodiment, fruits are conveyed from the transporter  12  to the calibrated fruit-reception region  320 . When the equipment  304  is in its filling position, the fruits are taken to the inlet end of the forced immersion sleeve  308 . The sleeve takes the fruits to the bottom of the container  302 . Under the effect of buoyancy, the fruits rise and accumulate in a plurality of layers inside the container  302 , being held by the cover-forming plate  306 . Once the container is full, it is extracted from the basin  300  together with the moving equipment  304 , such that during movement of the container, the plate  306  is maintained on the open end of the container so as to prevent any fruit from escaping. 
   In addition, it will be understood that as the fruits arrive progressively in the reception region  320  and accumulate in the container  302 , the water level in the vessel  300  tends to rise. Thus, the water flows out through the overflow  324  and accumulates in the buffer tank  332  so as to ensure there is no risk of the vessel  300  overflowing. 
   After a full container  302  has been extracted, the water level in the vessel  300  is reestablished by the pump  334  which returns the water temporarily stored in the buffer tank  332  back to the basin  300 .