An Overview of the MARELCO NOXX LFP. Anti-fouling System

Transcription

1 An Overview of the MARELCO NOXX LFP Anti-fouling System Version Date: June 2017

2 Table of Contents Introduction Overview of the scientific principles involved Anti-fouling system components Emitters Emitter mounts Control Panels Power supplies Junction boxes, wiring and connection cabling Data connection to shipboard management system Areas to be protected Seachest intake grids Seachests Crossover tanks Piping, strainers and valves between seachests and crossover tanks Pipes and manifolds exiting crossover tanks Bow thruster seachests, tunnels and propulsion equipment Electric or hydraulic primary propulsion equipment Conventional propulsion equipment including shafts, struts and props Rudders Fittings that are external to the hull such as keel coolers Hulls Installation of system components Emitters and emitter mounts Control Panels Power supplies Junction boxes, wiring and connection cabling

3 Introduction The two main objectives of any anti-fouling system are to prevent fouling from occurring on the structures to be protected and to minimize or eliminate any negative effects on the surrounding environment. EMCS Industries is proud to offer a non-polluting anti-fouling solution that will work from the smallest recreational vessel to the largest cruise ship. It can also be applied to structures in the marine environment that can be difficult to protect with conventional means. The Marelco NOXX LFP (formerly Hydrosonic Hull Tender) anti-fouling system is an electronic system that is fitted on the inside of the hull or structure to be protected. The system comprises one or more control panels and a set of emitters operating on 12 volts DC with minimal energy consumption. The control panels can be fitted in any convenient location and all the emitters are fitted on the inboard side of the hull, sea chest, crossover, piping systems, strainers etc. The Marelco NOXX LFP emitters produce a low volume, low frequency audio signal that is transmitted through the vessel surfaces to be protected. The signal is unacceptable to the invaders and is seen to them as a predatory environment, keeping them away. This therefore provides complete protection against infestation by marine pets such as barnacles, mussels, pinworms and other crustaceans. The equipment can operate continuously to provide ongoing protection. It does not interfere with any electrolysis, marine depth sounders or radio equipment. The system works regardless of the material used on the hull or inboard applications. There is no need to bring the vessel out of the water to install the equipment. The installation of this equipment does not remove pest growth already present. Consequently, once installed the area must be free of fouling at the time of commissioning, thereafter the Marelco NOXX LFP will keep the treated areas fouling free. Overview of the Scientific Principles involved During the development of the system laboratory research was conducted on the effects of low frequency sound on cyprids or barnacle larvae. Initially the larvae are very small and are free-swimming looking for a suitable place to attach. They have to find a landing spot within a limited amount of time of around 2 weeks for their survival. Groups of cyprids of age 0, 3, 6 and 13 days were tested for an exposed period of 20 hours. For each age group, there was significantly less attachment when exposed to the low frequency sound. The low frequency vibrations discourage them from attaching to the protected surface and encourage them to settle on nearby unprotected surfaces.

4 The study also found that low frequency sound causes no apparent harm to barnacle larvae. They are still competent to metamorphose after prolonged exposure to the sound waves. These low frequency sound vibrations may cause a behavioral modification in the barnacle larvae such as predator avoidance. It was found that high frequencies are ineffective for the prevention of attachment (the test was conducted at Woods Hole Oceanographic Institute using frequencies of khz which were ineffective and remained heavily fouled). In addition, high frequencies are used by large sea mammals to communicate and the high frequency had a negative effect on these animals. It was determined in the same testing that the low frequency method of antifouling was environmentally benign, and is unlikely to cause any structural damage. Ultrasonic frequencies (14 khz) by comparison are lethal to barnacle and mussel larvae. Their conclusion is that any antifouling device that could reduce the need for anti-fouling paints and lengthen the haul-out times for vessels would be positive for both the environment and costs. Low frequency sound was also shown to be effective to combat potential in fouling situations where other approaches are ineffective, such as inside pipes and cooling systems, and on surfaces that cannot be readily removed from the water. In summary, it would appear that the sound frequency is similar to the barnacle larvae's natural enemies, which they wish to avoid, so they swim away from the protected surface and find a more suitable unprotected surface for attachment. In addition, the sound vibrations may produce a very slight movement of the microscopic layer of the water against the surface being protected to make attachment more difficult as they test for a good spot to land. Anti-fouling System Components Emitters Emitters are compact at only 2.5 x 3, weighing 2.2lbs there aren t any holes or drilling involved because it simply attaches to the surface its protecting that will conduct the sound. They are certified waterproof too. They have an electrical impedance of 6 ohms and are connected to the output of the Control Panel. Each emitter comes complete with 20ft of wire already sealed at the Emitter end.

5 Emitters are fastened to the surface to be protected via a pedestal made from the same material as the mounting surface. If you examine an emitter, you will note that the body and the stem are not rigidly fastened together. Connection between the stem and the body is via a plastic membrane. It is this non-rigid membrane that allows the stem to impact the surface to be vibrated when the emitter is electrically excited. The heavy body of the emitter acts as a reaction mass, thus an inertial emitter transferring energy (vibration) from the heavy body to the surface to be vibrated. Each emitter can protect an area whose radius is up to 2.50 meters. Emitter Mounts For many applications to flat surfaces, a flat stainless steel pedestal for each emitter can be made, with a minimum size between 2 to 3 inches square. It needs to include a M14 machine screw for attaching the emitter in the centre of the pedestal. This central machine screw should not extend more than 3/8 inch above the flat surface of the pedestal. For round items such as pipes, the above method can be used, or a hounds-type strap around the pipe with the flat pedestal on top. Where possible, the material used to make the mounting pedestals be the same as that of the material to which it is to be attached. For example, a mounting plate of Plexiglas could be used to protect a fiberglass structure.

6 Control Panels The control panels are made up of PCB cards that provide the audio signal to drive the emitters. Each card has an output impedance of 8 ohms and can handle up to 24 emitters. Control Panels are powered by 12 volts DC and are connected to the set of emitters in a series-parallel configuration. The configurations are in sets of 12, 24 and 48 emitters wired to a junction box and a home run to the main control panel. The control panels are designed to run continuously, as the system must be turned on and active to be effective. Power Supplies The power supplies provide power to the Control Panel. If ship battery power of 12 volts DC is available, this is ideal provided these batteries are always kept charged. An alternative is to provide a power supply that takes the ship s normally available power and converts it to 12 volts DC. Solar power solutions providing 12 volts DC can also be used.

7 Junction Boxes, Wiring and Connection Cabling Junction boxes are used to make the series-parallel connections between a set of emitters. All wiring and cables should be marine grade, tinned and stranded wire, colorcoded to meet the standards as used on that vessel. Data Connection to Shipboard Management System This would be a data cable going from the junction boxes to the control panels. The Seafarer Monitoring System can be added to ensure proper management of all the emitters. The software shows the status and location of each emitter. Areas to be Protected Seachest Intake Grids

8 This is critical as it is the first point of entry of the vessel s salt water. Emitters should be placed on the sides of the hull in the frames adjacent to the intake grids. The number of emitters is based on the number of grids and their size. Seachests Each seachest surface inside the vessel would have emitters. Number of emitters and their spacing will be based on the area of each surface, where each emitter can protect an area whose radius is up to 2.83 meters.

9 Crossover tanks Each crossover tank surface inside the vessel would have emitters. Number of emitters and their spacing will be based on the area of each surface, where each emitter can protect an area whose radius is up to 2.83 meters. Ideally surfaces include the two ends, two sides and the top.

10 Piping, Strainers and Valves Between Seachests and Crossover Tanks Each item should be protected with a emitter. Some items like strainers can be very large so could use several emitters. Pipes and Manifolds Exiting Crossover Tanks Each item should be protected with a emitter. Some items like pipes and manifolds can be quite long so could use several emitters. Bow Thruster Seachests, Tunnels and Propulsion Equipment Each item should be protected with one or more emitters.

11 Electric or Hydraulic Primary Propulsion Equipment Each component should be protected with one or more emitters. Conventional Propulsion Equipment Including Shafts, Struts and Props Each component should be protected with one or more emitters.

12 Rudders Two or more emitters should be attached to the rudder shaft. Fittings that Are External to the Hull such as Keels and Keel Coolers Inlets, outlets and fastening points that attach to the hull should have emitters. Hulls Inside access to attach emitters must be available to protect those surfaces. Each emitter can protect an area whose radius is up to 8.5ft Installation of System Components The equipment to be installed consists of two parts: A Control Panel unit which is the main control. Emitters, the units which transmit the vibrations to the hull. Placement of Emitters The placement of emitters locations will be determined by EMCS Industries Ltd. The emitters are normally installed at a maximum spacing of 6m.

13 Mounting of Emitter Pedestal When the positions of the emitters have all been finalized, and clearly marked on the inside of the hull, the mounting pedestals can be fastened in the assigned and marked locations, Figure 1 below shows the details of the pedestals to be used for mounting the emitters. FIGURE 1 For all sea chests, sea suctions, cross overs etc the mounting pedestals are made of stainless steel and welded or screwed to the inboard side (as shown in Figure 1 above). For the G.R.P (Fiberglas) hulls a mounting plate of Plexiglas can be used. These should be coated with resin and firmly attached to the hull/seachest etc. In all cases, the central machine screw (#10:24) for attaching the emitter to the pedestal, should not extend more than 9.5mm (3/8 ) above the surface of the pedestal. This screw must be stainless steel, brass or other non-ferrous material. Where the pedestals are of aluminum, a stainless steel washer should be placed over the screw before mounting the emitter, as the emitter socket is made of brass.

14 Installing the Emitters Screw the emitters onto the pedestals as shown below in Figure 2. Note connectors must be a tightest in the 5 o clock position. FIGURE 2 Connecting to the Control Panel The Control Panel can be placed in the convenient location on the vessel, preferably near the ship s source of power. The unit requires volts D.C to operate. Reference to Figure 4 will show the unit s terminal connections. Inter-connections between the oscillator and the emitters are also shown. Complete the wiring connections to the main Control Panel as shown in Figure 4 and 5 below. The wiring is simple but the correct securing and placement can best be done by an authorised MARELCO technician.

15 FIGURE 4

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