Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/24—Earth materials
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
  • A01G24/00—Growth substrates; Culture media; Apparatus or methods therefor
  • A01G24/10—Growth substrates; Culture media; Apparatus or methods therefor based on or containing inorganic material
  • A01G24/18—Growth substrates; Culture media; Apparatus or methods therefor based on or containing inorganic material containing inorganic fibres, e.g. mineral wool
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/24—Earth materials
  • G01N33/245—Earth materials for agricultural purposes
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/84—Systems specially adapted for particular applications
  • G01N2021/8466—Investigation of vegetal material, e.g. leaves, plants, fruits

Definitions

• the present invention relates to a device for optical measurement of a parameter, or in other words a physical quantity, of the material of a plant substrate.
• the parameter in question may be the oxygen content or the acid content of the substrate, for example.
• the material of the substrate may be glass wool or rock wool, for example.
• European patent application EP 1 700 520 A1 describes a device for measuring the oxygen level at a plurality of positions in substrate material.
• the device makes use of a measuring apparatus, to which a plurality of sensors are connected.
• the sensors are each configured as lengths of glass fibre, which are provided with an oxygen-sensitive fluorescent coating at their free ends.
• the substrate is positioned on a plate in a gutter-shaped container. Upright pipes of varying length that extend into the substrate are fixed to the plate.
• the glass fibres are inserted into the substrate from the bottom side via the pipes, in such a manner that the respective coatings are located in the root area of plants that grow in the substrate.
• the known device has the drawback that it is not suitable for use on a larger scale and in an economically sound manner.
• the device as described appears to be intended rather for carrying out scientific research. Another drawback of the device as described is that there is a risk that the glass fibres are inserted deeper or, quite the contrary, less deep into the substrate than the length of the pipe through which a glass fibre extends. This entails the risk of incorrect measurements.
• the optical measuring device comprises a measuring unit that comprises a housing which comprises a hollow, pin-shaped portion which has an open first end and which is configured to be inserted into a substrate with said first end, and which has a second end that is located opposite the first end of the pin-shaped portion, wherein the measuring unit further comprises a stop portion which connects to the second end of the pin-shaped portion and which is configured to abut with a contact side thereof facing the pin- shaped portion against the upper side of the substrate into which the pin-shaped portion is inserted, wherein the device further comprises a first length of glass fibre which extends at least into the pin-shaped portion and which is rigidly connected thereto, a first end of which is located near the open first end of the pin-shaped portion, which first end of the first length of glass fibre is provided with a coating that is sensitive to the physical quantity that is to be measured, wherein furthermore the first length of glass fibre is or at least can be
• the measuring means can generate a light signal to the coating in the first length of glass fibre, which coating will reflect the light signal.
• the reflected light signal is received by the measuring means.
• the parameter in question is determined on the basis of characteristics of the generated light signal and the reflected light signal.
• Such a measuring method is described in US patent US 6,051 ,437 in which, as in EP 1 700 520 A1 , use is made of a fluorescent coating.
• a device as described above may be excellently suited for use from the upper side of a substrate, for example configured as a substrate mat.
• the use of the stop portion in combination with the feature that the first length of glass fibre is rigidly connected to the pin-shaped portion, which connection need not necessarily be a direct connection between the first length of glass fibre and the pin-shaped portion within the framework of the invention, makes it possible to precisely select the depth to which the first length of glass fibre and thus the coating on the first end thereof is inserted into the substrate thereof without precision being required in inserting the first length of glass fibre into the substrate.
• the invention to that end makes it possible to use measuring units with pin-shaped portions of varying length.
• US patent application US 2009/0166520 A1 describes a system for in situ measurement of the nitrate ion concentration in soil.
• the sensor that is used comprises a pin-shaped portion, within which a length of glass fibre extends.
• a cap assembly Provided at the upper side of the pin-shaped portion is a cap assembly, which in practice may extend above ground or below ground.
• the diameter of the cap assembly although slightly greater than that of the pin-shaped portion, is too small to function as a stop portion provided with a contact side, as upon insertion of the pin- shaped portion into a substrate, the cap assembly will not offer any resistance worth mentioning against further insertion of the pin-shaped portion into the substrate once the underside of the cap assembly makes contact with the substrate as, in contrast thereto, is the case with the invention once the contact side makes contact with the substrate.
• the contact side it is also preferable for the contact side to have a diameter at least two times, preferably at least three times, greater than that of the pin-shaped portion.
• the first length of glass fibre is not provided with a cladding, at least insofar as it extends into the pin-shaped portion.
• the stop portion is provided at least substantially concentrically relative to the pin-shaped portion, the ease with which a measuring unit can be inserted into a substrate with its pin-shaped portion is improved and the risk of the pin-shaped portion being obliquely inserted into the substrate can be reduced.
• the ease of use can be further increased if the pin-shaped portion is pointed at the first end and/or if the pin-shaped portion has a tapered longitudinal section.
• the second end of the first length of glass fibre is located near the second end of the pin-shaped portion or in the stop portion
• the device further comprises a further measuring unit provided with a engagement portion that is configured to be connected to the stop portion of the measuring unit, as well as a second length of glass fibre which is connected to the engagement portion and which has a first end that is optically connected to the second end of the first length of glass fibre in the connected state of the further measuring unit to the measuring unit, wherein the second end of the second length of glass fibre opposite the first end of the second length of glass fibre is or at least can be optically connected to measuring means for measuring the parameter on the basis of light signals reflected by the coating.
• Such an embodiment provides the practical possibility to have a plurality of measuring units, which can be produced at relatively low cost, (semi) permanently inserted in one or a plurality of substrates, for example distributed over a greenhouse, and to connect these measuring units to a further measuring unit at desired moments for measuring the desired parameter by means of the measuring means.
• the invention also provides a further measuring unit as such for use in a device according to the invention as discussed in the foregoing and as will be discussed yet hereinafter. If the engagement portion has an endless edge within which the first end of the second length of glass fibre is positioned, a reliable and accurate connection between the measuring unit and the further measuring unit can be realised in a constructionally simple manner. With a view to obtaining a stable connection it may further be advantageous in that case if the endless edge surrounds and connects to the stop portion in the connected state.
• the stop portion comprises a chamber which is in communication with the cavity of the pin-shaped portion and which is or at least can be in communication with the environment of the measuring unit via a passage, wherein the second length of glass fibre extends through the passage in the connected state of the further measuring unit to the measuring unit.
• a chamber has advantages in particular in combination with closure means (yet to be discussed) for which space is available within the chamber.
• a chamber may also be used if the first length of glass fibre is optically connected directly, i.e. not via a second length of glass fibre, to the measuring means.
• Such a permanent arrangement is in particular suitable for (semi) continuous measurements, where typically a measurement is carried out every four minutes, for example.
• closure means for closing the passage in the non- connected state of the further measuring unit to the measuring unit and for leaving the passage open in the connected state of the further measuring unit to the measuring unit, so that the second length of glass fibre can extend through the passage, unnecessary exposure of the first length of glass fibre, in particular of the coating on the first end thereof, can be prevented or at least be reduced. Depending on the type of coating, such exposure may lead to undesirable degradation of the coating.
• the closure means comprise a resilient flexible closure element which is connected to the stop portion and which is configured to close the passage in the non-connected state and to be clear of the passage in the connected state
• the closure means and in general the measuring unit can be of simple design.
• the pin-shaped portion and the stop portion may form an integral unit, which may lead to a lower cost price and a greater ease of use of the measuring device.
• the pin-shaped portion and the stop portion form part of one and the same component.
• Such a component may typically be an injection-moulded product, for example.
• the closure means may be positioned in the chamber, so that the chamber provides protection for the closure means.
• Figure 1 is a vertical cross-sectional view showing the use of the invention with a cultivating block
• Figure 2 is a vertical cross-sectional view showing the use of the invention with a substrate mat with the cultivating block of figure 1 thereon;
• Figures 3a and 3b are perspective views of a measuring device according to the invention, showing the further measuring unit in the unconnected state (figure 3a) and in the connected state (figure 3b) to the measuring unit of the measuring device.
• Figures 4a and 4b are vertical cross-sectional views showing the measuring device of figures 3a and 3b.
• Figure 1 shows a block-shaped cultivating block 1 .
• the cultivating block 1 consists in large part of substrate material 2, such as glass wall or rock wool, for example. On the underside of the substrate material, a number of parallel grooves 3 are provided for drainage of excess water.
• the cultivating block 1 further comprises a plastic film 4, which extends around and abuts the substrate material 2. Plastic film is not provided on the upper side and the underside of the cultivating block 1 .
• the substrate material 2 grows a young plant 5 to be further cultivated, for example a tomato plant or a paprika plant.
• the roots of the plant 5 extend into the substrate material 2.
• I n order to be able to stimulate the growth of the plant 5 it is important to have an insight, inter alia, into the conditions that prevail in the substrate material. These conditions can for example be expressed in parameter values such as those of the acidity of the substrate material and of the humidity of the substrate material.
• a measuring unit 6 is inserted in the substrate material 2 from above. This measuring unit 6 will be discussed in more detail hereinafter in the description of figures 3a-4b.
• the term “measuring unit” is not intended to express that the unit in question is independently capable of carrying out measurements.
• the term “measuring unit” is merely intended to indicate that the unit in question is intended to be of use in carrying out measurements, for example of the pH-value or of the degree of humidity of the substrate material 2.
• the cultivating block 1 with the plant 5 growing therein is placed on a beam-shaped substrate mat 1 1 once the plant 5 of figure 1 has reached a specific growth stage.
• the length of the substrate mat is such that two, three or more cultivating blocks 1 can be placed thereon with a certain spacing between them.
• the substrate mat 1 1 largely consists of substrate material 12, such as glass wall or rock wool.
• the substrate material is omnilaterally surrounded by a plastic film 14.
• the film 14 protects the substrate material against external influences, such as germs that might interfere with the growth of the plant 5, or against light so as to prevent algal growth in the substrate material.
• Openings are provided in the film 14 at the location of the cultivating blocks 1 that are placed on a substrate mat 1 1 , so that the underside of substrate material 2 of the cultivating blocks 1 directly connects to the upper side of substrate material 12 of the substrate mat 1 1 .
• the roots of the plant 5 continue to grow into the substrate material 12 of the substrate mat 1 1 after the cultivating block 1 has been placed on the substrate mat 1 1 . It is important, also in view of the further growth of the plant 5, to have an insight into specific parameter values of substrate material 12. In order to gain an insight into these values, a measuring unit 6 is inserted through the film 14 and into the substrate material 12.
• Figures 3a-4b show the measuring unit 6 in combination with a further measuring unit 16.
• the measuring unit 6 is at least in large part a plastic component made by injection-moulding.
• the measuring unit 6 has a housing comprising a hollow, pin-shaped portion 21 and a disc-shaped stop portion 22.
• the measuring unit further comprises a first length of unclad glass fibre 23, which extends into the cavity of the pin-shaped portion 21 , along the length thereof. Starting from the orientation shown in figures 1 2, both the lower end 24 and the upper end 25 of the pin-shaped portion 21 are open.
• the lower end 24 is free and has a pointed shape so as to facilitate insertion of the measuring unit 6 into the substrate material. It is for that reason that the pin-shaped portion 21 is also slightly tapered in downward direction.
• a coating 39 is provided on the lower end of the first length of glass fibre 23.
• the material of the coating 39 is sensitive to a physical or chemical quantity of the substrate material into which the measuring unit 6 is inserted.
• the lower end of the first length of glass fibre 23, and thus also the coating 39 is in contact with the substrate material and with the feed water in the substrate material in the inserted position of the measuring unit in the substrate material.
• the sensitivity of the coating 39 manifests itself in that light incident on the coating 39 via the first length of glass fibre 23 is reflected by the coating in a manner that makes it possible to determine the parameter value of the physical or chemical quantity to be measured, using measuring means not shown, on the basis of the difference between the characteristics of the incident light and the reflected light.
• the coating may be a kind of hydrogel, in other words, the coating may be a layer of hydrogel or comprise hydrogel.
• a hydrogel is a network of natural or synthetic polymer chains that are hydrophilic.
• a hydrogel has a high absorption capacity and contains water.
• Such hydrogel materials and coatings on the basis thereof are known to the skilled person in this field; they are not particularly limited for the present invention.
• the hydrogel comprises one or more compounds (substances) that are sensitive to the parameter to be measured, such as the oxygen content or the pH-value.
• Examples include compounds or combinations of compounds or chemical complexes, which emit light beams upon contact with a specific compound to be measured (oxygen in the case of measuring the oxygen content), which light beams can be measured and which are a measure of the amount of the compound to be measured from which the value of the parameter can be determined.
• the thickness of the coating ranges between 0.01 mm and 4.0 mm, for example, in one embodiment it ranges between 0.03 mm and 1 .00 mm.
• Examples of a coating that is suitable for measuring the oxygen content are described in European publication EP 1 700 520 A1 , inter alia in paragraphs [0009] and [0010] thereof, which paragraphs are to be regarded as incorporated herein. Further examples are given in International publication WO 01/63264 A1 , of which at least page 1 , lines 4-24 are to be regarded as incorporated herein.
• Examples of a coating that is suitable for measuring a pH-value are described in US publication US 2005/0090014 A1 , for example in paragraphs [0033] - [0038] thereof, which paragraphs are likewise to be regarded as incorporated herein.
• the upper end 25 of the pin-shaped portion 21 connects to the underside, hereinafter called the stop side 26, of the stop portion 22.
• the diameter of the stop side 26 is about four times larger than the diameter of the pin-shaped portion 21 , at least at the location where the pin-shaped portion 21 and the stop portion 22 join one another.
• a central opening 27 is provided in the bottom wall 28, which bottom wall 28 is integral with the pin-shaped portion 21 and whose underside forms the stop side 26, which is in communication with the cavity of the pin-shaped portion 21 .
• the first length of glass fibre 23 is fixedly connected to the bottom wall 28 with its upper end, for example by being glued in place in the central opening 27.
• the stop portion 22 also comprises a cap portion 29 having a circumferential wall 30 and an upper wall 31 that joins said circumferential wall.
• the bottom wall 28, the circumferential wall 30 and the upper wall 31 define an internal chamber 32.
• a central passage 33 is provided in the upper wall 31 .
• the passage 33 is closed by a leaf spring 34, for example made of metal, preferably a soft metal such as a copper alloy, which leaf spring is provided in the chamber 32 and which is connected to the underside of the upper wall 31 via a connection 35, for example a snap connection.
• a leaf spring 34 for example made of metal, preferably a soft metal such as a copper alloy, which leaf spring is provided in the chamber 32 and which is connected to the underside of the upper wall 31 via a connection 35, for example a snap connection.
• an edge may be provided on the underside of the upper wall 31 , which edge closely abuts the circumference of the leaf spring 34 so as to prevent ingress of light into the chamber 32 via a passage 33 as much as
• the further measuring unit 16 comprises a lid member 52 comprising an upper wall 53 and a circumferential wall 54 that joins the upper wall at the bottom side and the outer side thereof.
• the lid member 52 is made of aluminium.
• the further measuring unit 16 further comprises a second length of glass fibre 55, which, unlike the first length of glass fibre 23, is provided with a protective cladding, for example of stainless steel.
• a central passage 56 Provided in the upper wall 53 is a central passage 56, through which the second length of glass fibre 55 extends.
• the second length of glass fibre 55 is connected to the upper wall 53, for example by glueing, in such a manner that the lower end of the second length of glass fibre 55 is positioned just above the bottom side of the circumferential wall 54.
• the internal diameter of the circumferential wall 54 is just a little larger than the external diameter of the circumferential wall 30, so that the further measuring unit 16 can be slid over the stop portion 22 with a close fit from the upper side until the underside of the upper wall 53 abuts against the upper side of the upper wall 31 .
• the lower end of the second length of glass fibre 55 extends through the passage 33 and the leaf spring 34 deforms elastically, as indicated in figure 4b.
• the aforesaid lower end of the second length of glass fibre 55 will eventually connect to the upper end of the first length of glass fibre 23. In this way an optical connection between the two glass fibres 23 and 55 has been effected.
• the second length of glass fibre 55 is connected (or at least can be connected) to optical measuring equipment, which is capable of sending a light signal from said end via, in succession, the second length of glass fibre 55, the connection between the second length of glass fibre 55 and the first length of glass fibre 23 and the first length of glass fibre 23 to the coating 39.
• the coating 39 will reflect this light signal in a manner that depends on the values of a physical or chemical quantity of the substrate material with which the coating 39 is in contact.
• the measuring equipment is capable of determining the parameter value in question on the basis of (the difference between the emitted light signal and) the reflected light signal.
• measuring units 6 and further measuring units 16 the very practical possibility is created to keep a relatively large number of measuring units 6, distributed over various substrate materials, for example cultivating blocks or substrate maps, in a greenhouse, permanently, at least over a growth period of a plant, inserted in the substrate material.
• the measuring units 6 can be manually inserted into a substrate with their pin-shaped portions 21 until the stop side 26 of the stop portion 22 strikes the substrate.
• the lower end 24 is thus positioned at a defined depth equal to the length of the pin-shaped portion 21 .
• the leaf spring 34 ensures that hardly any light, if any, can reach the coating 39 via the passage 33.
• an operator can make his round past the various measuring units 6 with the measuring equipment and a further measuring unit 16 connected thereto at regular intervals, for example once or several times every day, and carry out a measurement with the measuring equipment for every measuring unit 6 after having temporarily connected the further measuring unit 16 to the measuring unit 6.

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• Life Sciences & Earth Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• Inorganic Chemistry (AREA)
• Food Science & Technology (AREA)
• Physics & Mathematics (AREA)
• Geology (AREA)
• Remote Sensing (AREA)
• Environmental & Geological Engineering (AREA)
• Pathology (AREA)
• Medicinal Chemistry (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Environmental Sciences (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)

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• 2016
  • 2016-02-15 NL NL2016260A patent/NL2016260B1/nl active
• 2017
  • 2017-02-13 WO PCT/NL2017/050085 patent/WO2017142398A1/en active Application Filing
  • 2017-02-13 EP EP17709820.9A patent/EP3417285A1/de not_active Withdrawn

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