Our Electric Fish Repelling Device emits pulses of electric current into the water. The electric pulses and their frequency cause muscle contractions to the fish. The fish interpret these contractions as a danger and they swim away from the area to escape.
Unlike other Electric Fish Repelling Devices, our system emits short polarity-changing sequences, which prevent fish moving towards our anodes (galvanotaxis)
We have developed unique optimization software, which determines optimum electrode location and pulse magnitude and frequency, for each installation site. This assures each system is tailored to the customers' requirements
Fish Return Systems can easily be retrofitted to our Screening Machines. Fish Return Systems include specially developed buckets mounted on each screen panel. The buckets transport fish, cyclostamata and other valuable species in front of the screen panels to a water filled trough. The trough is then lead to an area where the fish can be returned to the water source. The various illustrations shown in this chart demonstrate the different ways of emptying the fish buckets.
The sophisticated MultiDisc® technology can also be adapted to include special provisions for gentle fish recovery. Due to the rotation of the screening panels on a MultiDisc® the fish buckets are emptied directly into the return trough, with a low drop height.
Fish return troughs and debris troughs can be independent or combined based on customers' requirements.
Another option for gentle aquatic species protection is the use of the Geiger Traveling Band Screen with Fish Protection Provision. Here also the emptying of the fish buckets can be done independent from the debris trough. The special design features of the machine also ensure a low drop height.
Inadvertent fish mortality in screening plants can be significantly decreased by adding our fish return system to the Geiger Traveling Band Screens with in-to-out, or out-to-in flow patterns. When possible it is better to use the Geiger Traveling Band Screens with in-to-out flow pattern, because the fish are never dewatered. Existing Traveling Band screen machines installed at screening plants can also be equipped with fish buckets. However, due to the special design parameters very high drop heights may exist and there is no possibility to separate debris from the fish buckets
Fish Immobilization Systems are only used in connection with Fish Return Systems. The Fish Immobilization systems are located at the inlet chambers and prevent fish or cyclostomata from avoiding a Fish Return System. The system is used when it is likely that fish trying to avoid a Fish Return Ssystem may exhaust themselves.
The immobilization of the fish and cyclostomata in the inlet chamber is accomplished by the emission of short electric pulse sequences. The fish become momentarily immobilized and are then easily caught into the fish buckets of our rotating screen.
A Fish Immobilization System has to fulfill the following requirements:
For the mechanical as well as for the electro-technical design of a Fish Immobilization System many criteria must be taken into consideration, including:
We have developed a special optimization software, which determines exact positions of the electrodes and pulse frequencies, specifically tailored for each customers site.