WO2023244102A1

WO2023244102A1 - Greenhouse

Info

Publication number: WO2023244102A1
Application number: PCT/NL2023/050317
Authority: WO
Inventors: Peter Eduard Maria Lansu
Original assignee: Dalsem Beheer B.V.
Priority date: 2022-06-15
Filing date: 2023-06-08
Publication date: 2023-12-21
Also published as: NL2032172B1

Abstract

The invention relates to a greenhouse (1) for cultivating crops therein, comprising: multiple rows of support columns (2) for forming a roof support construction; a roof (4) having a roof passage; a horizontal separation plane within the greenhouse (1) dividing the greenhouse (1) in a cultivation space below the separation plane and a roof space above the separation plane, wherein the horizontal separation plane is configured for receiving a fabric screen (26); and a ventilation system (40) comprising a ventilation arrangement, the ventilation arrangement comprising a ventilation device at least for displacing air within the greenhouse (1), and an air duct (50) with an air inlet (55), an air outlet (56), and an air channel extending between the air inlet (55) and the air outlet (56), wherein the air channel debouches into the air outside of the greenhouse (1) via the roof passage and passes through the separation plane, and wherein the ventilation device is configured for drawing air into the air channel, wherein the air duct (50) comprises a top duct section located above the horizontal separation plane, and a lower duct section located below the horizontal separation plane and in fluid communication with the top duct section, wherein the top duct section has a stationary portion and a moveable portion hingeably connected to the stationary portion, wherein the moveable portion is moveable between a first position, in which the air channel is substantially closed, and a second position, in which a gap is present between the top duct section and the lower duct section at the level of the horizontal separation plane.

Description

GREENHOUSE

Horticultural or agricultural greenhouse

BACKGROUND

The invention relates to a horticultural greenhouse for cultivating crops therein .

Such a horticultural greenhouse, for example, is well-known from the Dutch patent publication NL2024182 . NL2024182 describes a horticultural greenhouse for cultivating crops therein, comprising multiple rows of support columns forming a roof support construction; a roof that is supported by the roof support construction, and that separates the greenhouse from the environment , wherein the roof of the greenhouse comprises a roof passage ; and a fabric screen for at least partially darkening and/or thermally shielding the greenhouse, wherein the fabric screen extends in a hori zontal separation plane within the greenhouse that divides the greenhouse in a cultivation space below the separation plane and a roof space above the separation plane . The horticultural greenhouse is further provided with a ventilation system comprising a first ventilation arrangement , wherein the first ventilation arrangement comprises a first ventilation device for displacing air within the greenhouse, and a first air duct with a first air inlet , a first air outlet, and a first air channel extending between the first air inlet and the first air outlet . The first air channel debouches into the air outside of the greenhouse via the roof passage , wherein the first air channel passes through the separation plane, and wherein the first ventilation device is arranged for drawing air into the first air channel .

SUMMARY OF THE INVENTION

Currently, so-called pull-in fabric screens are hugely on the rise . Such pull-in fabric screens allow complete webs of fabric screen to be pulled in from a first side wall of a greenhouse . Each web of the fabric screen is provided with flexible strips at the longitudinal sides thereof . The webs of fabric screen are configured to be inserted, for example, into a rail profile by one of the flexible strips , and into a rail groove of a screen profile by the other one of the flexible strips . In order to pull in a web of the fabric screen, a rope is connected to the web via an adapter whereafter the web of fabric screen may be pulled into the greenhouse from a second side wall opposite to the first side wall , wherein the web of the fabric screen is placed in the horizontal separation plane . After pulling in the fabric screen, there is no need to secure the fabric screen to the greenhouse by human . After installment , the fabric screen may be moved between an open state, in which the fabric screen is folded, and a closed state, in which the fabric screen darkens and/or thermally shields the cultivation space, by moving the screen profile between subsequent transverse frames .

In the known greenhouse, the air duct is passing through the horizontal separation plane . The air duct, thus , prevents the fabric screen from being moved between the open position and the closed position . This disadvantageously results in that a pull-in screen cannot be used in the known greenhouse . An owner of the horticultural greenhouse, thus , has to choose between an ventilation system configured for drawing air from the outside into the cultivation space as described above, or a so-called pull-in screen .

It is an obj ect of the present invention to overcome or to ameliorate the disadvantage of the known greenhouse , to improve the known greenhouse or to provide an alternative greenhouse .

According to a first aspect , the invention provides a horticultural greenhouse for cultivating crops therein, comprising : multiple rows of support columns for forming a roof support construction; a roof having a roof passage, which is supported by the roof support construction and separates the greenhouse from the environment ; a hori zontal separation plane within the greenhouse dividing the greenhouse in a cultivation space below the separation plane and a roof space above the separation plane , wherein the horizontal separation plane is configured for receiving a fabric screen for at least partially darkening and/or thermally shielding the greenhouse ; and a ventilation system comprising a ventilation arrangement , the ventilation arrangement comprising a ventilation device at least for displacing air within the greenhouse, and an air duct with an air inlet, an air outlet , and an air channel extending between the air inlet and the air outlet, wherein the air channel debouches into the air outside of the greenhouse via the roof passage and passes through the separation plane, and wherein the ventilation device is configured for drawing air into the air channel , wherein the air duct comprises a top duct section located above the hori zontal separation plane, and a lower duct section located below the hori zontal separation plane and in fluid communication with the top duct section, wherein the top duct section has a stationary portion and a moveable portion hingeably connected to the stationary portion, wherein the moveable portion is moveable between a first position, in which the air channel is substantially closed, and a second position, in which a gap is present between the top duct section and the lower duct section at the level of the horizontal separation plane .

During use of the horticultural greenhouse of the invention, for example after the so-called pull-in fabric screen is installed into the horticultural greenhouse , the pull-in fabric screen needs to be moved between the open state and the closed state . For example , the fabric screen is moved into the open state every morning, and into the closed state every evening . Movement of the fabric screen between the open state and the closed state promotes cultivation of the crops arranged within the cultivation space of the horticultural greenhouse . The top duct section of the air duct has the stationary portion and the moveable portion hingeably connected to the stationary portion, wherein the moveable portion is moveable between a first position in which the air channel is substantially closed, and a second position, in which a gap is present between the top duct section and the lower duct section at the level of the horizontal separation plane . As the moveable portion is hingeably connected to the stationary portion, the moveable portion may be moved between the first and second position relatively easily . For example , the moveable portion may be moved into the second position by pushing against it . This is advantageous , as the moveable portion may be moved into the second position by the fabric screen pushing against the moveable portion, thereby allowing the fabric screen to pass the air duct by moving through the gap between the top duct section and the lower duct section at the level of the horizontal separation plane . The horticultural greenhouse allows a user to use the ventilation system configured for drawing air from the outside into the cultivation space , and the so-called pull-in screen . The horticultural greenhouse according to the invention, thus , allows the user of the greenhouse to benefit from the ventilation system and from the pull-in fabric screen .

In an embodiment , the horticultural greenhouse further comprises one or more fabric screens extending within and/or parallel to the horizontal separation plane . In a preferred embodiment, at least one of the one or more fabric screens is configured for being moved between an open state and a closed state , in which the at least one of the one or more fabric screens thermally shields and/or darkens the cultivation area of the greenhouse at least partially . Preferably the at least one of the one or more fabric screens is provided with a screen passage configured for being aligned with the air channel when the at least one of the one or more fabric screens is in the closed state . An advantage of the screen passage aligned with the air channel of the air duct, when the fabric screen is in the closed state thereof , is that a free passage of air from the air inlet toward the air outlet of the air duct is enabled .

In an embodiment , the at least one of the one or more fabric screens comprises a strip arranged at a side of the fabric screen, wherein the strip is configured to be arranged within a screen profile configured for moving the fabric screen between the open and closed state . In an embodiment thereof , the moveable portion is configured to move from the first position to the second position upon the screen profile passing the air duct when moving between the open and closed state . Preferably the moveable portion is configured to be moved from the first position to the second position upon the screen profile abutting against the moveable portion when moving between the open and closed state . According to this embodiment , the screen profile may be used for moving the at least one of the one or more fabric screens between the open and closed state thereof . When the at least one of the one or more fabric screens is moved from the open state to the closed state , or vi ce versa, the screen profile has to pass the air duct . When the screen profile reaches the air duct, the screen profile abuts against the moveable portion of the top duct section of the air duct . As a result, the moveable portion is moved, in particular hinged, from the first position towards the second position, such that movement of the moveable portion is operated by means of the screen profile . When the screen profile has passed the air duct, the moveable portion may move, in particular, hinge back into the first position under influence of gravity . Therefore, an advantage of this embodiment is that, for example, no actuators are required for moving the moveable portion, such that working of the ventilation arrangement may be controlled relatively easily and reliable .

In an embodiment, the stationary portion of the top duct is arranged at the roof of the greenhouse . In an embodiment thereof , the moveable portion is arranged at the lower end of the stationary portion . As the moveable portion is hingeably arranged at the stationary portion, the moveable portion may be moved into the second position relatively easily . Because of the moveable portion being arranged at the lower end of the stationary portion, the moveable may move from the second position into the first position under influence of gravity . This is advantageous , as movement of the moveable portion between the first and second position may be achieved with a relatively simple construction .

In an embodiment, the moveable portion comprises a base plate extending substantially parallel to the separation plane and having an elongated base plate passage, and two or more hinging plates arranged hingeably, at one end thereof , at the base plate and, at another end opposite to the one end, at the stationary portion . According to this embodiment, the base plate is connected to the stationary portion by means of the two or more hinging plates . The hinging plates are hingeably arranged at the base plate and at the stationary portion, such that hinging may be performed around two separate hinging axes . As a result, movement of the moveably portion from the first position into the second position may comprise a sidewards and upwards movement . This is advantageous , as the space required for moving the moveable portion between the first and second position is kept to a minimum by means of the sidewards and upwards movement .

In an embodiment, the moveable portion comprises two upstanding edge plates arranged at the base plate and extending substantially transverse to the base plate and to the two or more hinging plates , wherein the two or more hinging plates are arranged between the two upstanding edge plates . In an embodiment thereof , a distance is present between the two upstanding edge plates , wherein the distance allows the lower end of the stationary portion to be received therebetween . When the moveable portion is in the first position, the upstanding edge plates and the two or more hinging plates , advantageously, define and close a part of the air channel of the air duct, such that air may pass from the air inlet of the air duct to the air outlet thereof .

In an embodiment, an abutting bar is provided between the two upstanding edge plates , wherein the abutting bar is configured for abutting against the stationary portion when the moveable portion is moved into the second position . In an embodiment thereof , an abutting bar is provided between the two upstanding edge plates and at each of the opposite ends thereof . The abutting bars are provided for abutting against the stationary portion when the moveable portion is moved to the second position, thereby preventing the moveable portion from moving too much upwards . The abutting bars , advantageously, prevent the moveable portion from becoming stuck in the second position because of moving too much upwards .

In an embodiment , the moveable portion is provided with a guiding ramp . In an embodiment thereof , the base plate , at the first end thereof , is provided with a first guiding ramp, and, at the second end thereof in longitudinal direction opposite to the first end, with a second guiding ramp, wherein each of the first and second guiding ramps extends from the base plate and is upwardly inclined with respect to the horizontal separation plane . The first and second guiding ramps advantageously allow for a smooth movement of the moveable portion between the first and second position thereof .

In an embodiment , the air duct comprises an intermediate duct section that is arranged between the top duct section and the lower duct section, wherein the top duct section, the intermediate duct section, and the lower duct section are arranged in series . In an embodiment thereof , the intermediate duct section comprises a stationary portion and a moveable portion that is hingeably connected to the stationary portion . In some greenhouse, two fabric screens are provided above each other, such that, for example, one fabric screen is used for darkening the cultivation space and the second fabric screen is used for thermally shielding the cultivation space . This embodiment advantageously allows both screens to pass the air duct of the ventilation arrangement .

In an embodiment , the ventilation arrangement comprises a first closing panel that is configured to move between a first position in which the first closing panel closes off the air channel , and a second position in which the first closing panel allows air to pass through the air channel . In an embodiment thereof , the air duct comprises in the roof space a further air inlet to the air channel , and a second closing panel that is configured to move between a third position in which the second closing panel allows air to pass through the further air inlet, and a fourth position in which the second closing panel closes off the further air inlet . Preferably, the first closing panel and the second closing panel are operably connected to each other for synchroni zed movement .

In an embodiment, the ventilation device comprises a fan connected to the air duct at the air outlet thereof for drawing air into the air channel . In an embodiment thereof , the ventilation device comprises an air blender that is provided between the air outlet of the air duct and the fan, wherein the air blender comprises a first blender inlet that is in air communication with the air outlet , a second blender inlet that is in air communication with the cultivation space , and a blender outlet that is in air communication with the fan, wherein the air blender is configured for providing an air blend from air from the cultivation space and air from the air channel to the fan .

In an embodiment, the ventilation system comprises multiple ventilation arrangements . An advantage of this embodiment is that the multiple ventilation arrangement allow for an even control of the climate within the horticultural greenhouse .

In an embodiment, the ventilation system comprises a top beam extending parallel to the separation plane, and wherein the air duct is supported by the top beam. In an embodiment thereof , the top beam comprises at least one top beam passage and the air channel extends through the at least one top beam passage .

In an embodiment, the roof support construction comprises transverse frames for supporting the roof , wherein the top beam extends between subsequent transverse frames in a direction transverse thereto, and wherein the fabric screen is guided over the top beam between the subsequent transverse frames .

The various aspects and features described and shown in the specification can be applied, individually, wherever possible . These individual aspects , in particular the aspects and features described in the attached dependent claims , can be made subj ect of divisional patent applications .

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be elucidated on the basis of an exemplary embodiment shown in the attached drawings , in which :

Figure 1 shows a schematic overview of a part of a greenhouse with multiple rows of support columns connected by transverse frames , a roof construction and a ventilation system according to an embodiment of the invention;

Figure 2 shows a cross-sectional view of a part of the greenhouse of figure 1 ;

Figure 3 shows a schematic overview of a part of the greenhouse of figure 1 , without the roof construction; and

Figure 4 shows a schematic sideview of the ventilation system of figure 1 .

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows an agricultural or horticultural greenhouse 1 according to an embodiment of the invention . The partially shown greenhouse 1 is in this example a Venlo type greenhouse, and comprises a number of identical metal columns 2 , for example metal lattice columns , that are positioned spaced apart and in rows oriented in the longitudinal direction L of the greenhouse 1 . The lattice columns 2 are connected by means of metal transverse frames 3 that extend in the transverse direction T of the greenhouse 1 , for forming a supporting structure for a roof 4 . The transverse frames 3 comprise a horizontal top bar 10 , a hori zontal bottom bar 11 extending below the top bar 10 , and diagonal brace struts 12 there in between .

The roof 4 of the greenhouse 1 comprises multiple identical support gutters 15 that extend parallel to each other in the longitudinal direction L of the greenhouse 1 . The support gutters 15 are in the transverse direction T of the greenhouse 1 alternately supported by the columns 2 or by the transverse frames 3 . The roof 4 further comprises multiple roof ridges 16 that extend parallel to the support gutters 15 in the longitudinal direction L of the greenhouse 1 . The support gutters 15 and the higher situated roof ridges 16 alternate in the transverse direction T of the greenhouse 1 . Multiple glass rods 17 are provided at the roof 4 , which extend in the transverse direction T of the greenhouse 1 between the support gutters 15 and the roof ridges 16 , and fixed glass panels 18 that are supported by the support gutters 15, the roof ridges 16 and the glass rods 17 along their circumference . The roof 4 separates the greenhouse 1 from the environment .

The roof 4 comprises a ventilation window assembly 20 that comprises multiple ventilation windows 21 . The ventilation windows 20 comprise glass panels 22 in frameworks 23 that are hingeably connected to one of the roof ridges 16 . In this exemplary embodiment, the ventilation windows 21 are shorter than the fixed glass panels 18 . Therefore, a horizontal window profile 24 is mounted between the two adj acent slanting glass rods 17 to form a rabbet for an additional fixed glass panel 25 below the ventilation windows 21 . The ventilation windows 21 are regularly distributed over the roof 4 , for example repeating alternating at the left side and right side of each roof ridge 16, wherein a repeating ventilation window 21 is provided after for example two fixed glass panels 18 . Hinging the ventilation windows 21 between an open position and a closed position, for example, may be done with slide rail assemblies that are known to the person skilled in the art .

As schematically shown in figure 2 , the greenhouse 1 comprises multiple fabric screens 26 that are provided between pairs of subsequent transverse frames 3 , and schematically shown parallel guiding wires 27 that extend in the longitudinal direction L of the greenhouse 1 between the top bars 10 thereof . Each of the screens 26 is a so-called pull-in screen and is slidably supported and guided along one or more of the guiding wires , and is configured for being moved between an open state and a closed state in which the screens 26 at least partially darken and/or thermally shield the cultivation space .

As shown in figure 2 , each fabric screen 26 has a first flexible strip 28 arranged at a first side of the fabric screen 26 , and a second flexible strip 29 arranged at a second side , opposite to the first side, of the fabric screen 26. The first flexible strip 28 is configured to be arranged within a rail profile 30 that is arranged at one of the transverse frames 3 , in particular at the top bar 10 thereof . A first sealing lip 31 is provided between the top bar 10 and the rail profile 30 . The second flexible strip 29 is configured to be arranged within a rail groove 32 of a screen profile 33 that is moveable between the top bars 10 of the subsequent transverse frames 3 in order to move the fabric screen between an open state , and a closed state . A second sealing lip 34 is provided at the screen profile 33 , in particular at the side facing away from the fabric screen 26. In the closed state the screen 26 extends in a substantially horizontal separation plane S and bound, together with the roof 4 , a roof space that is located above the separation plane S , and bound, together with nonshown side walls of the greenhouse 1 , a cultivation space that is located below the separation plane S . In the closed state the screens 20 darken and thermally shield the entire cultivation area of the greenhouse 1 . The closed state of the screen 20 enables the roof space and the cultivation space to have dif ferent climate conditions , for example with respect to air temperature , air humidity, and concentrations of carbon dioxide and oxygen in the air .

In this exemplary embodiment , the greenhouse 1 is provided with an additional fabric screen below each fabric screen 26, which additional fabric screen is arranged at the level of the bottom bars 11 of the subsequent transverse frames 3 .

The roof 4 has regularly distributed roof passages 35 of which one is shown in figure 1 . In this example the roof passage 35 has a rectangular shape and is located near one of the roof ridges 16. A first closing panel 36 is hingeably attached to the roof 4 near the roof passage 35, wherein the first closing panel 36 is configured to move between a first position in which the first closing panel 36 closes off the roof passage 35, and a second position in which the first closing panel 36 extends away from the roof 4 whereby it is open to allow fresh air to pass through the roof passage 35.

The horticultural greenhouse 1 comprises a ventilation system 40 that comprises the ventilation window assembly 20 , and that comprises a ventilation arrangement 41 for circulating air in the cultivation space and for drawing fresh air from outside the greenhouse 1 into the cultivation space .

As shown in figure 3 , the ventilation arrangement 41 comprises a top beam 42 extending between and substantially transverse to the two subsequent transverse frames 3 in the separation plane S . The top beam 31 has two oblique first top beam legs 43 which merge into a top beam center section 44 . The top beam 42 comprises a not shown elongated top beam passage within the top beam center section 44 .

The ventilation arrangement 41 further comprises a bottom beam 45 which is provided below and substantially parallel to the top beam 42 and that extends between and substantially transverse to the two subsequent transverse frames 3 . The bottom beam 45 has two oblique bottom beam legs 46 which merge into a bottom beam center section 47 . The bottom beam 45 comprises a not shown elongated bottom beam passage within the bottom beam center section 47 . The bottom beam passage is located directly below and is aligned with the top beam passage .

The first ventilation arrangement 41 comprises an air duct 50 that is arranged at and supported by the top beam 42 and the bottom beam 45. The air duct 50 comprises a top duct section 51 , an intermediate duct section 52 and a bottom duct section 53 which are arranged in series . The top duct section 51 is mounted to the top beam 42 around the top beam passage and extends therefrom towards the roof passage 35. The top duct section 51 has a rectangular cross section, and converges in a direction from the roof 4 towards the top beam 42 . The intermediate duct section 52 extends between the top beam 42 and the bottom beam 45 and is respectively mounted thereto around the top beam passage and the bottom beam passage . The intermediate duct section

52 has a rectangular cross section . The bottom duct section

53 is mounted to the bottom beam 45 around the bottom beam passage and extends therefrom downwards into the cultivation space . The first bottom duct section 53 has a rectangular cross section and diverges substantially parallel to the transverse direction T of the greenhouse 1 , and converges substantially parallel to the longitudinal direction L of the greenhouse 1 in a downwards direction away from the bottom beam 45.

The air duct 50 , at the upper end of the top duct section 51 near the roof 4 , has a rectangular air inlet 55 that is near and/or adj acent to the roof passage 35 . At the lower end of the bottom duct section 53 , which is located within in the cultivation space, the air duct 50 has a substantially square shaped air outlet 56. The top duct section 51 , the intermediate duct section 52 and the bottom duct section 52 of the air duct 50 together define an air channel that extends between the air inlet 55 and the air outlet 56.

In this exemplary embodiment, the air inlet 55 and the roof passage 35 are arranged near and/or adj acent with respect to each other . The top duct section 51 of the air duct 50 may also be part of the construction of the roof 4 and therewith define the roof passage 35 in the roof 4 . The top duct section 51 may also extend through the roof 4 and therewith define the roof passage 35 in the roof 4 .

The air duct 50 , in particular the top duct section 51 thereof , is further provided with a second closing panel 57 that is movably connected to the top duct section 51 near the air inlet 55. Although not shown, closing panel actuators are provided, which are configured to move the second closing panel 57 between an open position in which the closing panel 57 allows air to pass from the roof space into first air channel , and a closed position in which the second closing panel 57 prevents air from the roof space from entering the air channel .

The ventilation arrangement 41 is provided with a ventilation device 60 comprising an air blender 61 that is connected to the air outlet, and a fan 62 that is connected to the air blender 61 . The air blender 60 is configured for determining whether air is drawn into the air blender 60 from the cultivation space to circulate, and/or air is drawn into the air blender 60 from outside the greenhouse 1 , wherein the ratio of air from outside the greenhouse 1 and air from the cultivation space can be regulated . The first air blender 60 then provides an air blend from air from outside the greenhouse 1 and air from the cultivation space to the fan 60 . By means of the closing panel 57 , additionally, it may be determined whether air is drawn into the air blender 60 from the roof space .

Optionally, the horticultural greenhouse 1 may comprise a not shown heat exchanger arranged downstream of the first fan 65 , such that air from the first air blender 60 flows along the heat exchanger in order to cool or heat the passing air .

As shown in figures 3 and 4 , the top duct section 51 has a stationary portion 70 and a moveable portion 71 that is hingeably connected to the stationary portion 70 . As is clear from the figures , the stationary portion 70 is arranged at the roof 4 of the greenhouse 1 at the upper end thereof , while the lower end thereof is at a distance from the top beam 42 , and the moveable portion 71 is connected to the lower end of the stationary portion 70 . The moveable portion 71 , thus , is provided between the top beam 42 and the stationary portion 71 of the top duct section 51 .

The moveable portion 71 comprises a base plate 72 that is arranged substantially parallel to the separation plane S . The base plate 72 has a width that substantially corresponds to the width of the top beam 42 , a length that is larger than the length of the stationary portion 70 at the level of the lower end thereof , and a longitudinal direction substantially parallel to the longitudinal direction of the top beam . The base plate 72 is provided with a not shown elongated base plate passage that may be aligned with the elongated top beam passage such that air is allowed to pass from the top duct section 51 towards the lower duct section 53 .

At the side facing away from the cultivation space and facing towards the roof space, the base plate 72 is provided with two upstanding edge plates 73 that extend over substantially the complete length of the base plate 72 . The upstanding edge plates 73 are placed at such a distance from each other, that the lower end of the stationary portion 70 may be received between the upstanding edge plates 73 . The height of the upstanding edge plates 73 is , preferably slightly, larger than the distance between the top beam 42 and the lower end of the stationary portion 70 of the top duct section 51 . At the edge facing away from the base plate 72 and at the opposite ends thereof , abutting bars 74 are provided between the upstanding edge plates 73 . Each of the abutting bars 74 is configured for abutting against the lower end of the stationary portion 70 of the top duct section 51 .

Additionally, hinging plates 75 are provided at the base plate 72 at the side thereof facing away from the cultivation space . The hinging plates 75 are arranged between the two upstanding edge plates 73 and extend substantially transverse to the upstanding edge plates 73 and to the separation plane S . At a first end thereof , each of the hinging plates 75 is hingeably connected to the base plate 72 such that each of the hinging plates 75 may be hinged within respect to the base plate 72 about a first hinging axis 76. At a second end thereof , opposite to the first end thereof , each of the hinging plates 75 is hingeably connected to the stationary portion 70 of the top duct section 51 , in particular the lower end thereof , such that each of the hinging plates 75 may be hinged with respect to the stationary portion 70 about a second hinging axis 77 . The height of the hinging plates 75 substantially corresponds to the distance between the top beam 42 and the lower end of the stationary portion 70 of the top duct section 51 .

The hinging plates 75 are arranged such that the moveable portion 71 may be moved between a first position, in which the base plate 72 is located against the top beam 42 and the elongated base plate passage is aligned with the elongated top beam passage, and a second position, in which the base plate 72 is hinged upwards and sideways with respect to the top beam 42 as is schematically shown in figure 4 .

The base plate 72 , at the first end thereof , is provided with a first guiding ramp 78 , and, at the second end thereof in longitudinal direction opposite to the first end, with a second guiding ramp 79 . Each of the first and second guiding ramps 78 , 79 extends from the base plate 72 and is upwardly inclined with respect to the hori zontal separation plane S . The first and second guiding ramps 78 , 79 are provided such that the screen profile 33 when moving towards the open or closed state abuts against one of the first and second guiding ramps 78 , 79 . For example, when the screen profile 33 in figure 4 moves from right to left , the screen profile 33 abuts against the first guiding ramp 78 . By moving the screen profile 33 further to the left , the first guiding ramp 78 is pushed to the left . As a result , the moveable portion 71 hinges with respect to the stationary portion 70 from the first position to the left and upwards into the second position, such that a gap, as shown in figure 4 , is provided between the base plate 72 and the top beam 42 . The gap is sufficient for allowing the screen profile 33 , together with the screen 26 , to pass beyond the air duct 50 of the first ventilation arrangement 41 . When the screen profile 33 has passed the air duct 50 , the moveable part 71 moves back into the first position, for example, under influence of gravity . When the screen profile 33 in figure 4 moves from left to right, the moveable portion 71 hinges with respect to the stationary portion 70 from the first position to the right and upwards into the second position . This allows the screen profile 33 to pass the air duct 50 of the ventilation arrangement 41 when the screen needs to be moved into the open or closed state . The screen 26 is provided with a not shown screen passage that is configured to be aligned with the air channel of the air duct 50 when the screen 26 is in the closed state .

As shown in figure 4 , the intermediate duct section 52 also comprises a stationary portion and a moveable portion that constructively is equivalent to the moveable portion of the top duct section .

It is to be understood that the above description is included to illustrate the operation of the preferred embodiments and is not meant to limit the scope of the invention . From the above discussion, many variations will be apparent to one skilled in the art that would yet be encompassed by the scope of the present invention .

Claims

C L A I M S

1 . Horticultural greenhouse for cultivating crops therein, comprising : multiple rows of support columns for forming a roof support construction; a roof having a roof passage, which is supported by the roof support construction and separates the greenhouse from the environment ; a hori zontal separation plane within the greenhouse dividing the greenhouse in a cultivation space below the separation plane and a roof space above the separation plane , wherein the horizontal separation plane is configured for receiving a fabric screen for at least partially darkening and/or thermally shielding the greenhouse ; and a ventilation system comprising a ventilation arrangement , the ventilation arrangement comprising a ventilation device at least for displacing air within the greenhouse, and an air duct with an air inlet, an air outlet , and an air channel extending between the air inlet and the air outlet, wherein the air channel debouches into the air outside of the greenhouse via the roof passage and passes through the separation plane, and wherein the ventilation device is configured for drawing air into the air channel , wherein the air duct comprises a top duct section located above the hori zontal separation plane, and a lower duct section located below the hori zontal separation plane and in fluid communication with the top duct section, wherein the top duct section has a stationary portion and a moveable portion hingeably connected to the stationary portion, wherein the moveable portion is moveable between a first position, in which the air channel is substantially closed, and a second position, in which a gap is present between the top duct section and the lower duct section at the level of the horizontal separation plane .

2 . Horticultural greenhouse according to claim

1 , further comprising one or more fabric screens extending within and/or parallel to the horizontal separation plane .

3 . Horticultural greenhouse according to claim

2 , wherein at least one of the one or more fabric screens is configured for being moved between an open state and a closed state , in which the at least one of the one or more fabric screens thermally shields and/or darkens the cultivation area of the greenhouse at least partially, preferably wherein the at least one of the one or more fabric screens is provided with a screen passage configured for being aligned with the air channel when the at least one of the one or more fabric screens is in the closed state .

4 . Horticultural greenhouse according to claim

3 , wherein the at least one of the one or more fabric screens comprises a strip arranged at a side of the fabric screen, wherein the strip is configured to be arranged within a screen profile configured for moving the fabric screen between the open and closed state .

5. Horticultural greenhouse according to claim

4 , wherein the moveable portion is configured to move from the first position to the second position upon the screen profile passing the air duct when moving between the open and closed state, preferably wherein the moveable portion is configured to be moved from the first position to the second position upon the screen profile abutting against the moveable portion when moving between the open and closed state .

6. Horticultural greenhouse according to any one of the preceding claims , wherein the stationary portion of the top duct is arranged at the roof of the greenhouse .

7 . Horticultural greenhouse according to any one of the preceding claims , wherein the moveable portion is arranged at the lower end of the stationary portion .

8 . Horticultural greenhouse according to claim

7 , wherein the moveable portion comprises a base plate extending substantially parallel to the separation plane and having an elongated base plate passage , and two or more hinging plates arranged hingeably, at one end thereof , at the base plate and, at another end opposite to the one end, at the stationary portion .

9. Horticultural greenhouse according to claim

8 , wherein the moveable portion comprises two upstanding edge plates arranged at the base plate and extending substantially transverse to the base plate and to the two or more hinging plates , wherein the two or more hinging plates are arranged between the two upstanding edge plates .

10 . Horticultural greenhouse according to claim

9, wherein a distance is present between the two upstanding edge plates , wherein the distance allows the lower end of the stationary portion to be received therebetween .

11 . Horticultural greenhouse according to claim 9 or 10 , wherein an abutting bar is provided between the two upstanding edge plates , wherein the abutting bar is configured for abutting against the stationary portion when the moveable portion is moved into the second position .

12 . Horticultural greenhouse according to claim 11 , wherein an abutting bar is provided between the two upstanding edge plates and at each of the opposite ends thereof .

13 . Horticultural greenhouse according to any one of the claims 8- 12 , wherein the moveable portion is provided with a guiding ramp .

14 . Horticultural greenhouse according to claim 13 , wherein the base plate, at the first end thereof , is provided with a first guiding ramp, and, at the second end thereof in longitudinal direction opposite to the first end, with a second guiding ramp, wherein each of the first and second guiding ramps extends from the base plate and is upwardly inclined with respect to the hori zontal separation plane .

15. Horticultural greenhouse according to any one of the preceding claims , wherein the air duct comprises an intermediate duct section that is arranged between the top duct section and the lower duct section, wherein the top duct section, the intermediate duct section, and the lower duct section are arranged in series .

16. Horticultural greenhouse according to claim 15, wherein the intermediate duct section comprises a stationary portion and a moveable portion that is hingeably connected to the stationary portion .

17 . Horticultural greenhouse according to any one of the preceding claims , wherein the ventilation arrangement comprises a first closing panel that is configured to move between a first position in which the first closing panel closes off the air channel , and a second position in which the first closing panel allows air to pass through the air channel .

18 . Horticultural greenhouse according to any one of the preceding claims , wherein the air duct comprises in the roof space a further air inlet to the air channel , and a second closing panel that is configured to move between a third position in which the second closing panel allows air to pass through the further air inlet , and a fourth position in which the second closing panel closes off the further air inlet .

19. Horticultural greenhouse according to claim 17 and 18 , wherein the first closing panel and the second closing panel are operably connected to each other for synchronized movement .

20 . Horticultural greenhouse according to any one of the preceding claims , wherein the ventilation device comprises a fan connected to the air duct at the air outlet thereof for drawing air into the air channel .

21 . Horticultural greenhouse according to claim 20 , wherein the ventilation device comprises an air blender that is provided between the air outlet of the air duct and the fan, wherein the air blender comprises a first blender inlet that is in air communication with the air outlet, a second blender inlet that is in air communication with the cultivation space, and a blender outlet that is in air communication with the fan, wherein the air blender is configured for providing an air blend from air from the cultivation space and air from the air channel to the fan .

22 . Horticultural greenhouse according to any one of the preceding claims , wherein the ventilation system comprises multiple ventilation arrangements .

23 . Horticultural greenhouse according to any one of the preceding claims , wherein the ventilation system comprises a top beam extending parallel to the separation plane, and wherein the air duct is supported by the top beam.

24 . Horticultural greenhouse according to claim 23 , wherein the top beam comprises at least one top beam passage and the air channel extends through the at least one top beam passage .

25 Horticultural greenhouse according to claim 23 or 24 , wherein the roof support construction comprises transverse frames for supporting the roof , wherein the top beam extends between subsequent transverse frames in a direction transverse thereto , and wherein the fabric screen is guided over the top beam between the subsequent transverse frames .

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