PLANT CULTIVATION CHAMBER

Abstract: A cultivation chamber for plants and prestages thereof, comprising an outer chamber and an inner chamber, the inner chamber being arranged in the outer chamber in such a manner that spaces are formed on the one hand between the roof (1) and the ceiling (5) of the chambers and, on the other hand, between the sidewalls (2, 7 and 3, 8, respectively). The sidewalls (7, 8) of the inner chamber terminate at a distance from the floor (4) of the outer chamber, thereby forming gaps. Circulation means (9, 10) for circulating the air in the chamber are arranged such that air is supplied to the inner chamber via perforations (6) in the ceiling (5) thereof and is allowed to pass downwards through the inner chamber to be deflected at the floor to pass through said gaps and upwards in the spaces between the walls (2, 7 and 3, 8, respectively) and between the roof (1) and the ceiling (5).

Description: PLANT CULTIVATION CHAMBER The present invention relates to a cultivation chamber for plants and prestages thereof, such as seeds and cuttings, more precisely to a plant cultivation chamber for providing a reproducible climate when culti¬ vating plants and prestages thereof. In plant breeding, particularly in plant research, it is most important to create in a cultivation chamber a uniform, reproducible cultivation climate to be able to develop and, above all, select the best varieties. It is also important that the chamber is designed such that as similar conditions as possible prevail over the entire surface of a horizontal plane in the chamber (cultivation surface) with respect to light conditions, air humidity, temperature etc. Prior art cultivation chambers suffer from a number of drawbacks. They are thus expensive and inflexible, in so far as they generally require considerable alterations of and place restrictive demands on the installation sur¬ roundings, and the requirements described above are only satisfied to a certain extent. Cultivation chambers having a similar field of application and corresponding dimensions are available on the market and are characterised by air being pressed into a space under the perforated floor, then flowing upwards through the chamber so as to be finally passed into ducts in the side walls and recirculated to the space under the floor. This circulation of air is provided by fans, and cooling coils are in many cases arranged in connection with the fans. This principle of circulation involves several draw¬ backs. A significant drawback is that the basic require¬ ment that a cultivation surface be uniform, i.e. the cultivation chamber having a horizontal plane, is not satisfied , since the air is more rapidly changed at the edges of the cultivation tables in the chamber as compared to the centre of the tables because of the air flowing upwards from the floor. First of all, these circumstances may result in considerable variations in temperature over the cultivation surface, but of course also many other parameters will be affected. The inhomogeneity of the growth conditions is most undesired since it results in differences in the growth and development of the plant material and consequently strongly obstructs e.g. a selec tion of the cultivation material regarding genetically conditioned qualities. The principle of circulation meaning that air is supplied from below further implies a high velocity of fl to achieve fairly equivalent air humidity and temperature conditions over the entire cultivation surface. A constan wind having a velocity of up to several meters per second can easily give negative effects on the plants, besides being disagreeable to the staff and also rendering their work difficult, for example when reading symptoms of a disease. When simulating a sunny day, the differences in temperature will be pronounced between the centre and the periphery of a group of plants which are arranged in a cultivation chamber using the above-mentioned principle of circulation, since air is supplied to the plants from below and central regions therefore have a low rate of air chang . SE-A-16302/70 discloses a cultivation chamber having a cultivation space whose air temperature and air moisture are controllable. The air circulates according to a prin- ciple which is reversed in relation to the one described above. The cultivation chamber has no perforated roof to facilitate an even distribution of the supply air over the cultivation surface, and moreover the fan arrangement described therein is placed under the floor of the cultiva tion space, which necessitates considerable changes in connection with the installation. The object of the invention is to essentially reduce the above-mentioned drawbacks and provide a cultivation chamber which has almost uniform growth conditions over the entire cultivation surface, has a reproducible climate, is flexible so that it may be installed in an existing build¬ ing, without necessitating any major changes, and besides is considerably cheaper than existing cultivation chambers. The energy consumption of the cultivation chamber according to the invention in full operation is about one third of that used in similar prior art chambers which operate according to the principle described above. The reason for the low energy consumption is the motion of the air and the lack of an intermediate ceiling under the light fittings, which implies fewer lamps and, consequently, a reduced need of cooling. The above object is achieved by means of the cultiva¬ tion chamber having the characteristic features stated in claim 1. A preferred embodiment will now be described with reference to the accompanying drawing in which the only figure is a cross-sectional view of the cultivation chamber. As illustrated in the drawing, the cultivation chamber is box-shaped and comprises an outer chamber defined by a roof 1, side walls 2, 3 and a floor 4, and an inner chamber defined by a ceiling 5 having perforations or holes 6, and side walls 7, 8. The side walls 7, 8 extend in parallel with and at a distance from the side walls 2, 3 of the outer chamber, thereby forming a respective space, and terminate at a distance from the floor 4, thereby forming gaps between the floor and lower end portions of said side walls 7, 8. The ceiling 5 of the inner chamber is spaced from the roof 1 of the outer chamber and thus forms a space therebetween. Moreover, the cultivation chamber comprises circulation means in the form of fans 9, 10 which in the embodiment illustrated are arranged in the respective space defined by the walls 2, 7 and 3, 8, respectively. The fans 9, 10 for circulating the air in the cultivation chamber are arranged such that air is supplied to the inner chamb via the perforations 6 in the ceiling 5 and is allowed to pass downwards through the inner chamber to be deflected the floor 4 to pass through the gaps formed by the walls 8, and the floor 4 and upwards in the spaces defined by t walls 2, 7 and 3, 8, respectively, and the roof 1 and the ceiling 5. The cultivation chamber further comprises tem¬ perature controlling units 11, 12 in the form of heating and cooling elements which are arranged in said spaces, light fittings 13 and air humidifiers and dehumidifiers ( ot shown). Further the cultivation chamber comprises a control system for controlling the climate-affecting units (9-13 as well as the air humidifier and the air dehumidifier), recording units, such as printers, display units for demonstrating, inter alia, air humidity and temperature, and a climate-setting unit, i.e. a control panel on which the desired temperature, air humidity, length of the day etc are set (all of them not shown). According to a preferred embodiment, the inner dimen sions of the chamber are width = 2360 mm, depth = 2800 mm and height = 2200 mm. The inner walls 7, 8 are made of e.g. polyurethane sheets on the surface of which painted metal sheeting is mounted. The ceiling 5 is made of plastic-coated metal sheeting with perforations 6 and has a degree of perforation of up to 30%, preferably 10-20%. The light fittings 13 (12 pieces) comprise lamps which are either high-pressure sodium (NaV super) type or halogen (HQI-T) type lamps. The former produce a light exceeding 46,000 lux, the latter a light exceeding 23,000 lux, both measured at a distance of 1.12 m from the lamps. Experi¬ ments have proved that different crops develop optimally by means of one or the other type of lamp. A mixture of both types is also possible and, in some cases, preferred. The lamps may be controlled individually to simulate the different light conditions of a day, divided into day, night and twilight. Moreover, the lamps are arranged in such a manner that a significantly more uniform distribu¬ tion of light over the cultivation surface is achieved, as compared to prior art cultivation chambers. The invention is not limited to the embodiment described above and illustrated in the drawing, but modi¬ fications and variations are possible within the scope of the invention as defined in the claims.

Claims: CLAIMS 1. Cultivation chamber for plants and prestages thereof, comprising an outer chamber defined by a roof, side walls (2, 3) and a floor (4), and an inner chamber defined by a ceiling (5) and side walls (7, 8) and arranged in the outer chamber in such a manner that spaces are formed on the one hand between the roof (1) and the ceiling (5) and, on the other hand, between the side walls (2, 7 and 3, 8, respectively), the side walls (7, 8) of the inner chamber terminating at a distance from the floor (4) of the outer chamber to form gaps, the cultivation chamber further comprising means (11, 12) for controlling the room temperature, light fittings (13) and circulation means (9, 10) for circulating the air in said chamber, c h a r a c t e r i s e d in that the ceiling (5) is formed with perforations (6), and that the circulation means (9, 10) are arranged such that air is supplied to the inner chamber via the perforations (6) in the ceiling (5) and is allowed to pass downwards through the inner chamber to be deflected at the floor (4) to pass through said gaps and upwards in the spaces defined by said walls (2, 7) and said walls (3, 8), respectively, and said roof (1) and said ceiling (5). 2. Plant cultivation chamber as claimed in claim 1, c h a r a c t e r i s e d in that the circulation means (9, 10) are arranged in said spaces between the walls (2, 7 and 3, 8, respectively) to produce an upwardly directed air flow therein. 3. Plant cultivation chamber as claimed in claim 1 or 2, c h a r a c t e r i s e d in that said ceiling (5) has a degree of perforation of up to 30%.

Inventors: BJOERKLUND HANS, BJOERKLUND, HANS
Applicants: SVALOEF AB
Application year: 1992
Main classification: A01G9
IPC codes: A01G9