Abstract:
A system comprising cultivating tables as well as an irrigation device for supplying a liquid medium to cultivation products being cultivated on the cultivating tables, a special feature being the fact that each cultivating table comprises an inlet and an outlet for the medium, with said inlet and/or said outlet comprising coupling means for detachably coupling adjacent cultivating tables.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates to a system comprising cultivating tables as well as an irrigation device for supplying a liquid medium to cultivation products being cultivated on the cultivating tables. The liquid medium is in particular water, which may or may not contain nutrients for the cultivation products, whilst the cultivation products themselves are usually potted plants or the like. It is noted that the invention is not limited to a specific irrigation method. Thus, the irrigation device may operate according to a so-called ebb-and-flow system, in which the cultivating tables are cyclically inundated to a certain level during a flow period and allowed to run completely dry during an ebb period so as to prevent in particular root rot and fungus occurring at the bottom side of the cultivation products. According to another irrigation method, the water is applied to the cultivation products directly or in drops above the cultivating tables.  
         [0003]     2. Description of the Related Art  
         [0004]     Such a system operating according to the aforesaid ebb-and-flow system, comprising ten to twenty cultivating tables, for example, is known from U.S. Pat. No. 5,355,618 (Pedersen). In this known system, water is supplied as the irrigation medium in a central inlet pipe under the cultivating tables, in which a magnetically actuated main valve can open the central supply of water during a flow period and shut it off during an ebb period.  
         [0005]     One drawback of the system that is known from the aforesaid US patent publication is the following. Nowadays it is usual to position cultivating tables side-by-side (i.e. without aisles) in a greenhouse in order to optimally utilize the space in said greenhouse. The cultivating tables roll on rails installed in the greenhouse in that case. Thus it is possible to move a cultivating table (via an automated system) to an adjoining space, where a manual operation (for example pruning or harvesting) of the cultivation products being cultivated on said cultivating table is to be carried out. Staff present in said adjoining space are thus not exposed to high temperatures and/or polluted air in the greenhouse. The known system is not suitable for this kind of use, since it concern a system of stationary cultivating tables.  
       SUMMARY OF THE INVENTION  
       [0006]     The invention includes coupling elements each comprising a valve which closes on its own accord in the uncoupled position of the coupling elements. Since the valve automatically closes as soon as the coupling elements become detached from each other, i.e. upon detachment of the respective cultivating tables, leakage of the liquid medium is prevented. At least one of the coupling elements is designed in a telescopic manner whereby a portion of the element extends outwards to facilitate a connection between the mating elements. Thereafter, when they are disconnected, the telescopic portion of the element is retractable into a housing to make the element flush with a side of the table and to avoid damage to components during movement of the tables. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  is a partially longitudinal section of two coupling elements, showing the coupling elements in uncoupled position.  
         [0008]      FIG. 2  is a partially longitudinal section of two coupling elements, showing the coupling elements in partially coupled position.  
         [0009]      FIG. 3  is a partially longitudinal section of two coupling elements, showing the coupling elements in a coupled position.  
         [0010]      FIG. 4  is a partial section view showing an alternative embodiment of the invention whereby the coupling means operates in a telescopic manner.  
         [0011]      FIG. 5  is a top perspective view of a plurality of cultivating tables illustrating their movement relative to each other. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0012]     In a preferred embodiment of a system according to the invention, the valve comprises a valve member which is movable between a first position, in which the coupling elements are coupled, and a second position, in which the coupling elements are uncoupled, said valve member opening the valve in said first position and closing the valve in said second position. In particular, the valve member can move from said first position to said second position under the influence of the action of a spring. The valve is a spring-loaded non-return valve in that case, therefore, which provides a seal when the coupling elements are being uncoupled.  
         [0013]     In another preferred embodiment of a system according to the invention, the valve members of mating coupling elements push against each other in said first position.  
         [0014]     The invention also relates to a cultivating table apparently suitable for use in a system according to the invention.  
         [0015]     The invention furthermore relates to coupling elements apparently suitable for use in a system according to the invention.  
         [0016]     The invention will be explained in more detail hereinafter with reference to the Figures:  
         [0017]     The Figures show two mating coupling elements A and B, which are each built up as follows. The coupling element A comprises a substantially tubular housing  1 , which can be mounted on a water outlet of a cultivating table (not shown) at its one end  2 , for example by means of a screwed or a glued joint, and which can be moved into an end  3 ′ of a (likewise substantially tubular) housing  1 ′ of the coupling element B at its other end  3  ( FIGS. 2 and 3 ). An end  2 ′ of the housing  1 ′ disposed opposite the end  3 ′ can be mounted on a water inlet of an adjacent cultivating table (likewise not shown), also by means of a screwed or a glued joint, for example. The two housings  1 , 1 ′ comprise a steel coil spring  4 , 4 ′, which is supported on an internal, radially inwardly extending edge  5 , 5 ′ of the housing  1 , 1 ′. The coil spring  4 , 4 ′ allows movement under spring load of a valve member  6 , 6 ′ disposed in the housing  1 , 1 ′ between a first position (in which the coupling elements A and B are coupled; see  FIGS. 2 and 3 ) and a second position (in which the coupling elements A and B are uncoupled; see  FIG. 1 ). In the first position ( FIG. 3 ) the valve member  6 , 6 ′ opens a valve thus formed, and in the second position ( FIG. 1 ) said valve member automatically closes the valve. Leakage of water during the uncoupling of adjacent cultivating tables, for example when one of said cultivating tables is moved off over rails installed in a greenhouse, for the purpose of manually pruning or harvesting—in a separate space—cultivation products being cultivated on said cultivating table, is impossible, therefore. As the Figures show, the valve member  6 , 6 ′ is circumferentially provided with legs  7 , 7 ′, which engage the coil spring  4 , 4 ′, as well as with pins  8 , 8 ′. Said pins  8 , 8 ′ push against each other in the aforesaid first position (in which the coupling elements A and B are coupled; see  FIGS. 2 and 3 ). A cap  9 , 9 ′ is present between the legs  7 , 7 ′ of each valve member  6 , 6 ′ for reducing the flow resistance of the water.  
         [0018]     The end  3 , 3 ′ of the housing  1 , 1 ′ is made up of a separate, hat-shaped element  10 , 10 ′, which is connected to the housing  1 , 1 ′ by means of a gland nut  11 , 11 ′ with the interposition of a ring-shaped element  12 , 12 ′. The end  2 , 2 ′ is integrally connected to the housing  1 , 1 ′. In order to prevent leakage of water during operation, rubber sealing rings  13 , 13 ′ are provided. In the illustrated embodiment, the housing  1 , 1 ′, the valve member  6 , 6 ′, and the elements  10 , 10 ′;  11 , 11 ′;  12 , 12 ′ are made of plastic material.  
         [0019]      FIGS. 4A &amp; 4B  illustrate an alternative design of the coupling means that prevents the components from extending outwards to be possibly damaged by other equipment when the table is moved relative to other equipment. The embodiment includes a cylindrical portion of at least one coupling member that is movable outwards from a housing under the influence of water pressure to force a male portion into a female portion of the other member and effect a coupling between the parts. After the water or other fluid has been passed through the apparatus and the parts are disconnected, the cylindrical portion is moveable back into the housing, typically by a stationary member that urges the portion in the direction of the housing as the table moves past the stationary member. Preferably, the retracted cylindrical portion results in the valve assuming a position within a spatial footprint of the table. In this manner the likelihood of damage to the parts is reduced.  
         [0020]      FIG. 4A  shows a cultivating table  26  having sides  29  with a female coupling member  20  at one side and a male coupling member  22  at an opposite side. In  FIG. 4A  the male coupling member includes the telescopic cylindrical portion  23 . In order to connect the table to adjacent tables, female coupling member  20  receives a telescopic portion of an adjacent male member  25  as shown in  FIG. 4B . Likewise, at the other side of the table, the telescopic member  24  of male coupling  22  is extending to facilitate connection with a female coupling  27  on another adjacent table.  
         [0021]      FIG. 5  shows the coupling means of the invention in use with a plurality of cultivating tables  30 - 35 . As illustrated, the tables move in a first direction and then a second direction as shown by arrows  36 ,  37 . In the first instance the tables are connected together so that fluid may be passed between them. In the second instance they are disconnected for separate transportation to anther location. For example, in  FIG. 5 , tables  30 ,  31 , and  32  are coupled together using the coupling means of the invention. Table  33  is shown having been disconnected from table  32 . Visible extending thorough wall of table  33  is cylindrical portion that was urged outwards by water pressure as previously described in order to mate with a mating female member of table  32 . In the example shown in  FIG. 5 , the telescopic male member is urged back inwards by a stationary inclined member  50  which is constructed and arranged to intersect the passing table. In another embodiment, the telescopic cylindrical portion could be urged inwards by a spring or other biasing member disposed in its housing.  
         [0022]     The invention is not limited to the embodiment as discussed above, but it also extends to other variants that fall within the scope of the appended claims.