FI80529B - Arrangement for counting fish one at a time - Google Patents

Description

1 80529

Equipment for counting fish one by one. - Anläggning för att räkna fiskar en i sänder.

The invention relates to an apparatus for counting fish according to the preamble of claim 1, in which a beam curtain is formed by means of a plurality of transceiver pairs connected to an electronic counting unit.

Various counting devices have recently been developed for use in the rearing of juvenile fish, with which the number of juvenile salmon, especially those of migratory age, released directly into water bodies can be automatically recorded without touching the fish. One such calculating device is presented in Finnish patent application no. 854235. In the apparatus disclosed in said application, the measuring arrangement is performed in such a way that the beam produced by the laser in the measuring flange is reflected back and forth several times from the prisms of the prism frame and ends in a photocell forming a light curtain covering the entire aperture. The number of fish passing through the light curtain is recorded on the basis of the rupture of the laser beam by means of a photocell and an adjustable electronic device connected to it.

It is an object of the invention to provide an improved apparatus for counting fish one by one, comprising a plurality of transceiver pairs connected to an electronic counting unit, pairs of rods on opposite sides of a measuring flange opening mounted in pairs on substantially the same line, the total reflection is prevented and only the longitudinal rays of the rod emanating from the radiation source travel from the transmitter rod over the measuring opening to the corresponding receiver rod and further along to the receiver sensor, causing a registration event. The apparatus 2 80529 according to the invention is characterized in that the length of the rods is chosen so that the temperature of the outer ends of the rods remains above the dew point of the ambient air, even if the temperature of the water flowing through the device is well below said dew point.

The invention will now be described with reference to the accompanying drawings, in which:

Figure 1 shows a measuring arrangement according to the invention in a partially sectioned cross-section with respect to the direction of water flow,

Fig. 2 shows the measuring arrangement according to Fig. 1 in section II-II, and

Figures 3a, 3b show the transmitter and receiver rods according to the invention on an enlarged scale.

According to Figures 1 and 2, the measuring arrangement according to the invention comprises a measuring flange 1, preferably hard plastic, in which transmitter rods 4 with radiation sources 3 are mounted on one edge of the formed opening 2. Receiver rods 6 with receiver sensors 5 are mounted on the opposite side of the opening. that they are essentially on the same line with each other. Radiation sources 3 and receiver sensors 5, preferably phototransistors, are connected to the measuring flange 1, preferably by means of rubber plates 9 and covers 10, which are preferably fastened by bolts 11 and nut pins j "; 12 to the measuring flange 1. The measuring flange 1 is further connected to a watertight housing 13 ( shown by dotted lines in Fig. 1) preferably on the side surfaces of the measuring flange.The instrument housing 13 can also be mounted above the measuring flange 1.

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Fig. 3a shows a transmitter rod 4 for use in a measuring arrangement according to the invention, having optically smooth spherical surfaces 7 at both ends. Fig. 3b shows a receiver rod 6 for use in a measuring arrangement according to the invention, having optically smooth planar surfaces perpendicular to the longitudinal direction of the rod. Rods 4 and 6 are preferably sanded with transverse scratches and coated with black matt paint. This coating means that no total reflection inside said rods can take place, but only the longitudinal beams 14 from the radiation source 3 pass from the transmitter rod 4 over said measuring opening 2 to the receiver rod 6 and along it to the receiver sensor 5. This ensures that any oblique scatter 15 cannot be reflected on the receiver sensors 5, but each beam only affects its own receiver sensor. Li. The scissors black matte surface absorbs outgoing stray radiation 16.

The length of the rods is preferably chosen so as to allow the temperature of the outer ends of the rods 4, 6 to be kept above the dew point of the ambient air in all situations, even if the temperature of the water flowing through the device is well below said dew point.

The counting of the fish takes place in such a way that when the fish swims through the radial curtain of the opening 2 it causes a change in the activation of the receiver sensors 5, whereby the sum of the currents leaving the receiver sensors 5 changes as a function of the width of the fish. The total current changes so that as the width increases, the current decreases and, correspondingly, as the width decreases, the current increases. The current continues to increase until the fish has completely swam through the curtain. If the next fish swims so close to the one above that there is no gap between them, the total flow does not reach its maximum value, but starts to decrease again as a function of the width of the new fish. On the basis of the change points in the total flow (minimum maximum values), individual fish can be distinguished from each other, even if there is no gap between them. The calculation unit can be adjusted so that it only takes into account periods exceeding a certain minimum limit, thus eliminating, for example, error values given by debris, etc.

Claims (2)

1. Laitteisto kalojen laskemiseksi yksitellen, joka laitteisto käsittää useamman lähetin-vastaanottoparin kytkettynä elektroniseen laskentayksikköön, mittauslaipan (1) aukon (2) vastakkaisilla puolilla olevat sauvaparit (4,6), jotka on asennett säteilyä absorboivalla aineella, jolloin sauvojen sisällä tapahtuva kokonaisheijastuminen on estetty ja ainoastaan séteilylähteestä (3) lähtevät sauvan (4) pituussuuntaiset séteet (14) kulkeutuvat lähetinsauvasta (4) 5) aikaansaaden rekisteröintitapahtuman, tunnettu siitä, että sauvojen (4,6) pituus on siten valittu, että sauvojen (4,6) ulkopäiden appropriate to pysyy 6 80529 An apparatus for counting fishes at a transmitter, the facility of which comprises several transmitter-receiver pairs connected to an electronic calculator, on opposite sides of the opening flange (1) of the measuring flange (1) (4.6), installed in pairs essentially on the same straight line, the coarse surface surfaces of the rods are profiled and lined with a straining absorbent, preventing the total reflection occurring within the rods and emitting rays (14) of the rods (4) only from the radiation source (3). longitudinal direction preferably from the transmitting rod (4) over the measuring aperture (2) to the corresponding receiver rod (6) and along this further to a receiver encoder (5) in order to achieve a registration process, characterized in that the length of the bars (4.6) is selected so that the temperature at the outer ends of the rods (4.6) is poured above the dew point of the surrounding air, even though the temperature of the water flowing through the plant is well below said dew point.