Anti-fouling System Installation & Operational Manual

Transcription

1 Anti-fouling System Installation & Operational Manual Vessel hull number T061 Customer Name TRINITY YACHTS Cathelco Reference Number CA60001 Revision number Original CA23444 (LATEST MANUAL FORMAT) Cathelco Ltd Marine House, Dunston Road, Chesterfield S41 8NY, United Kingdom, Telephone +44 (0) Fax +44 (0) Sig NB Date 5-Jul-12

2 Table of Contents SECTION 1 System Specification System size calculation Current Settings Scope of supply and weights per hull supplied by Cathelco...7 SECTION 2 Information Project identification Cathelco contact data Definitions Application Safety Approvals (and certification) Liability Warranties Intellectual Property...10 SECTION 3 The Principles of the Cathelco System The problem The Cathelco solution Basic principle Corrosion suppression The control panel Current reduction relays (Optional) System variations Anode Types Corrosion/Fouling Suppression in Sea chests Fresh or Brackish Water Operation Effect on Hull Cathodic Protection Forms of Fouling not Controlled by Cathelco Systems Treatment of Feed and Process Water Dosage Rates and Anode Life System Flushing Procedure...17 SECTION 4 Installing Nano Anodes Nano Anodes Anode with integral cathode Submersible anode Omni anode Submersible cathodes Pico anode Installation of submersible anodes with nylon mounting / Omni Anodes in strainer lid SECTION 5 Anodes Installation and Positioning Installation of treatment (electrolysis) tanks

3 5.2 Painting...24 SECTION 6 Control Panels Electrical Installation Cable Sizes and Types Cable Installation Power Supply Peripheral Circuits Testing Retrofit Installations Systems fitted with Current Reduction Relays...28 SECTION 7 Operating & Maintaining a Cathelco A/F System Daily Checks Current Settings Anode Life Fresh Water Seawater Supply Management Anode Change/Replacement Routine Maintenance Maintenance of electrolysis (treatment) tank systems Anode renewal in electrolysis (treatment) tanks...32 SECTION 8 Troubleshooting a Cathelco A/F System...33 SECTION 9 Testing and Commissioning a Cathelco A/F System Application Dry Tests Flooded Tests Open Circuit Potential Check Resistance Check Leak Check Function Check Wiring Verification Validation...36 SECTION 10 Commissioning Check List...37 SECTION 11 Project Specific Drawings...38 SECTION 12 Log Sheet for Anti-fouling System...39 SECTION 13 Appendix Recommended welding procedures Fitting Cathelco anti-fouling systems to vessels with aluminium hulls

4 SECTION 14 CATHELCO LIMITED STANDARD TERMS AND CONDITIONS

5 Table of Figures Figure 1 Basic Circuit...11 Figure 2 Typical Seachest Arrangement...12 Figure 3 Strainer Installation...14 Figure 4 In-Line (Pipe) Installation...14 Figure 5 Electrolysis Tank...15 Figure 6 Dedicated Cathode Arrangement...16 Figure 7 Nano Anodes...18 Figure 8 - Anode Orientation...20 Figure 9 Clearance for Weld-in Sleeves...21 Figure 10 Clearance for flanged sleeves...21 Figure 11 Mounting Anodes in Direct Flow (Plan View)...22 Figure 12 Clearance from Structural Members...23 Figure 13 Control Panels...26 Figure 14 Cable Colour Coding...26 Figure 15 Cable Supply Sizes...27 Figure 16 Power Consumption...28 Figure 17 - Galvanic Potential Ranges in Salt Water

6 SECTION 1 System Specification 1.1 System size calculation Anode Location Anode Life/Renewal every 1 x MG to be fitted in each of 4 strainers 1 year When re-ordering please quote Drawing No. A2573/60001 and the anode part number from table Current Settings The current settings which appear below should be used in most circumstances. If, however, there continue to be signs of fouling, refer to Section 7.2 for guidance on current settings. Current Settings for EB/NS Nano Panels When a strainer is not in use the setting for that anode = 0.04 amps (04 On Display) The actual Life of the anodes depends on the actual operation of the system, Anode Size Current 0.1 amps Current 0.2 amps 100/40 1 Year 6 Months 150/ Years 8 Months 100/ Years 8 Months 150/ Years 1.1 Years The actual life of the anode depends on the actual operation of the system; the above stated values assume continuous current setting and should be used as a guide. Note : On vessels where the strainers are self draining when not in use the current will automatically reduce when the anode is dry and the panel will show a reading of 0 amps. Switch off at the control panel when removing the anodes from the strainers. The higher the current setting the shorter the anode life. The lower the current setting the greater the anode life. Installation Spares Each new system is supplied with an Installation Spares Kit with spares which are specific to the equipment that has been supplied. These spares are for use during the initial fitting only. On Board Spares - Consumables 2 off fuses for control panel modules and 2 off fuses for control panel power unit, spare fuses fixed to inside rear of control panel casing. 6

7 1.3 Scope of supply and weights per hull supplied by Cathelco Cathelco Reference number: CA60001 Qty Description Cathelco Part No Weight. Each/kg Total Weight/kg 2 Anodes Ref : MG2525 QUZ107NC PAAZQUZ107NC 2.5 kg 5.0 kg 2 Anodes Ref : MG2525 QZZ107NC PAAZQZZ107NC 1.7 kg 3.4 kg 1 Control Panel EB/NS/4W 12-24v DC Painted : RAL 9010 PAPEBNS04W 3.0 kg 3.0 kg 1 Installation spares kit PAY kg 0.5 kg Total Nett weight of system 11.9 kg Supplied by Client/Contractor Cables from control panel to junction box Power supply cable Earth return cables Junction Boxes All Cable Glands as Required Power source required 12-24v DC 7

8 SECTION 2 Information 2.1 Project identification This manual refers to a Cathelco marine salt water pipe work anti-fouling (A/F) and corrosion suppression (C/S) installation. A combined system is referred to in short as an A/F system. 2.2 Cathelco contact data For technical matters, Tel +44 (0) Fax +44 (0) technical@cathelco.com For parts and component replacement quotations and purchase, Tel +44 (0) Fax +44 (0) sales@cathelco.com Please refer to the Cathelco website, for any additional contact information and for the locations of our agents worldwide. 8

9 2.3 Definitions Anode A/F, C/S Cable tail Cathode Client Contractor Earth Earth Fault Electrolyte FSR Inspection Authority Peripheral Sleeve Stud The electrode through which direct current enters an electrolyte. Anti-fouling, corrosion suppression. An A/F system can also have C/S components. A double insulated cable, generally 2 metres long, connecting an anode to a junction box. The electrode through which direct current leaves an electrolyte. The purchaser of the equipment or service. The shipyard or other party responsible for installing the equipment. In metal ships, the ship s structure is the earth, also known as ground. An unintentional connection between a live conductor and earth. A liquid in which electric current flows by the movement of ions. Field service representative. An engineer or technician authorized by Cathelco to commission a new system, and to carry out tests and repairs on Cathelco equipment A classification society and/or other organization having responsibility for compliance with the applicable ship safety regulations. A sensor such as a flow switch, valve, on-off proximity switch, pump on-off contact, which activates a relay in the control panel. A permanent watertight fitting in which anodes are mounted. A solid or hollow threaded steel bar forming part of an anode, by which the anode is fastened into its sleeve. 9

10 2.4 Application The generic parts of this manual apply to all commercial steel hulled vessels, including military vessels where commercial standards are specified, and semi-submersible MODU s. They may not apply to combat military vessels where shock test or other special requirements are specified, stationary offshore or onshore installations, or jack-up MODU s. 2.5 Safety Cathelco equipment is sold on the assumption that personnel handling, installing, operating or repairing it obey the safety rules of their workplace. In addition, this manual highlights specific safety warnings in the appropriate sections, and it is VERY IMPORTANT that these warnings be heeded. 2.6 Approvals (and certification) Cathelco operates under ISO 9001:2000 Quality Assurance standards and the Lloyd s Register of Shipping approved manufacturer scheme. Not being essential to the ship s continued operation or survival, the components of a Cathelco system are not normally individually approved or certified. Component certification by a Class or other authority surveyor can be arranged at extra cost and with reasonable notice. 2.7 Liability Cathelco s liability in warranty claims is limited to the value of the goods supplied. Please refer to our Standard Terms and Conditions as shown in SECTION 14 at the back of this manual. 2.8 Warranties Standard warranty is for 12 months from the date of commissioning, provided that the system is fully commissioned by a Cathelco Authorised Service Engineer and a signed copy of the Commissioning Check List sent to Cathelco. In order to meet the warranty requirements it is essential that monthly log sheets are recorded and returned to Cathelco. Failure to follow the instructions in the manual can void the warranty. 2.9 Intellectual Property The contents of this manual and all drawings associated with it are protected by copyright and intellectual property law. They should only be reproduced for purposes in connection with installing or operating Cathelco equipment. The word Cathelco, whether capitalized or not, is registered by Cathelco Ltd. as a trade mark or brand name in many but not all maritime jurisdictions. In this manual it is simply used as a convenient abbreviation for the company name, Cathelco Ltd. 10

11 SECTION 3 The Principles of the Cathelco System 3.1 The problem The settlement and growth of marine life forms in salt water piping systems in ships and other marine installations can be very costly. The resulting problems include overheating and possible shut-down of machinery, accelerated corrosion, and reduced fire fighting capability. The flow velocity and temperature in these systems are more often than not ideal for encouraging the larvae of marine animals to enter the adult stage after they have passed through the inlet strainers, and settle on the available surfaces of pipes, heat exchangers, valves, etc. The most common culprits are blue mussels, barnacles and tubularia. It is not practical to filter out the tiny spores and larvae of these creatures, thus filtration has to be supplemented with water treatment. 3.2 The Cathelco solution Basic principle Cathelco anti-fouling systems are based on the fact that the main fouling organisms can be inhibited from growing by the introduction of very small quantities of copper into the water. The required dosage per litre is only a few parts per billion. This amount is of the same order of magnitude as the copper content in a typical sample of sea water. Copper is introduced into the water flow by electrolysis, in the form of positive ions. Thus the principle is known as copper ion generation, or CIG. Sea water is a good electrolyte, and a low DC voltage is sufficient to provide the necessary current. Figure 1 shows the electrolysis circuit in its simplest form. D.C. Source Anode + - Cathode Figure 1 Basic Circuit In the simplified circuit with a copper anode, the cathode would in time become copper plated, and this effect can indeed be observed with Cathelco systems when there has been zero flow for a significant period. 11

12 In practice, the majority of Cathelco systems are arranged as shown in Figure 2. Figure 2 Typical Seachest Arrangement The negative conductor from the power source is connected (earthed) to the ship s structure, which is in effect the cathode. The ions are carried by the water flow through the piping system. The copper ion concentration can still be high enough to inhibit the targeted marine growth one hundred meters or more from the anode Corrosion suppression With Cathelco systems, it is relatively simple and economic to supplement the anti-fouling function by adding corrosion suppression (C/S) anodes. They are energized by the same control panel as the antifouling (A/F) anodes, as shown in Figure 2. Experience has shown that by consuming the C/S and A/F anodes at the same rate by volume (with the convenience that all anodes are ready to change at the same time), substantial corrosion suppression is gained. In the case of ferrous piping, the C/S anodes are aluminium, and with cuprous piping they are iron. The Al anodes emit aluminium hydroxide ions, which form a protective coating on the inside of the pipes. Cuprous pipes (CuNi, CuNiFe, AlBro) are much more resistant to sea water corrosion than steel, but are nevertheless susceptible to what is known as impingement corrosion. (This form of erosion/corrosion is generally associated with the impingement of a high velocity, flowing liquid containing air bubbles against a solid surface.) The iron anodes emit ferrous ions, which give significant protection from this form of corrosion. Marine engineers are familiar with the use of iron or steel sacrificial anodes fitted in the headbox of a shell and tube condenser having cuprous tubes and tube sheets. The Cathelco anodes perform the same function, the only difference being that they are live, with a controlled rate of ion emission. Although it is extremely unusual, some vessels have aluminium sea water piping (AlBro is acceptable, see above). Cathelco A/F and C/S systems should not be installed in such cases. 12

13 3.2.3 The control panel Depending on their design, Cathelco control panels require a range of supply voltages:- 110 volt single phase AC 220 volt single phase AC volt DC AC power is transformed and rectified to a 0 12 volt DC output. The output voltage is automatically adjusted to maintain a constant current to each of a number of anodes. In general, each anode is controlled individually. The great majority of systems work with a current range of 0 2 amps per anode, manually adjustable in 0.2 amp steps. Using a conservative figure of 50% for panel efficiency, input power per anode can not exceed 48 watts. In practice, the power consumption of a ten anode panel will seldom exceed one quarter of a kilowatt. A/F panels are dust and spray tight to IP65, and are thus suitable for mounting in machinery spaces not too far from the anodes which they control Current reduction relays (Optional) As an optional extra the current setting can be modified automatically using peripheral devices such as flow switches, pump starter contacts, and valve open/close contacts. The peripherals are wired to current reduction or on/off relays in the panel which modify the current to the relevant anodes. The relays can also be manually activated by HI-LO switches mounted on the panel for convenient re-setting of the anode currents from seagoing to harbour sea water flow conditions and vice versa. Some installations include a slave panel with appropriate indicator lights, mounted in a convenient location from which the main panel(s) can be switched on or off or between HI and LO conditions System variations The seachest mounted anodes illustrated in Figure 2 are the preferred arrangement and the one used on the majority of installations. It is usually simpler than the alternatives, and, as well as protecting the seachest much more effectively than anti-fouling paint, it introduces the ions at the furthest upstream point in the pipe run, thus ensuring uniform dosage of the water regardless of its destination. The disadvantage is that anodes fitted in seachests can only be changed with the vessel in dry dock, or in the case of top mounted anodes by sealing off the chests with diver installed patches. With the trend to five year docking intervals, or in the case of retro-fits, it can be undesirable or physically impossible to fit sufficient quantity/size of anodes in the sea chests. The alternative locations for the anodes are : In the intake strainers Figure 3 In the intake pipes on large vessels Figure 4 In the electrolysis tanks Figure 5 In the case of an electrolysis tank, a source of sea water with sufficient head delivers water through the tank where it is dosed and injects it in the main intake(s). The dosage is of course calculated for the total flow through the pumps, but can be at a far higher concentration in the electrolysis tank loop, in order to keep the pipe size down. Up to one hundred times the concentration is acceptable. 13

14 Weld-in sleeve out 2 core cable from panel Anode Junction box Typical strainer installation showing weld-in sleeve. Seawater in The sleeve can be nylon. Metallic strainer assumed, which must be well earthed. Seawater out Strainer basket Figure 3 Strainer Installation Pipe upstand and flange sleeve must be used. Earth return Seawater in Seawater out Figure 4 In-Line (Pipe) Installation 14

15 Cathode Seawater in Anode Seawater out Figure 5 Electrolysis Tank Anode Types Cathelco produces a variety of anode types. Combination A/F and C/S anodes on the same stud are available for restricted space applications, and mounting sleeves are available for installation of new anodes from the wet or the dry side Corrosion/Fouling Suppression in Sea chests. Generally at dry docking of vessels with seachest mounted anodes, the anti-fouling paint shows very little deterioration and the sacrificial anodes in the chests are only partially used. Nevertheless, Cathelco recommends fitting sacrificial corrosion protection anodes and applying anti-fouling paint. This is to give protection in areas of the chest with little or no flow, or where dedicated cathodes are fitted, or in case of premature depletion of the anodes Fresh or Brackish Water Operation. The standard control panel maximum output voltage is usually sufficient to operate the anodes at full current in water with up to two or three times the resistivity of standard ocean water, or about 75 ohmcm, which includes many estuarial and coastal waters. However, in truly fresh water the system will go to maximum voltage with little or no current output, and it should be switched off if this situation lasts more than a few days. See also SECTION 7 of this manual. In brackish or very dirty water the same results may have been seen which include a drop in output current. This will rectify itself once the vessel is back in seawater Effect on Hull Cathodic Protection In a typical Cathelco system, the effect of using the hull structure as part of the return (negative) path for the anode current is to reduce the hull potential with respect to a standard reference cell. In other words, it is reinforcing the function of the hull cathodic protection system, be it by impressed current (ICCP) or sacrificial anodes. Usually, the effect is insignificant, but in very large A/F installations the reduction can amount to a few tens of millivolts, and where owners prefer not to have the systems interact, Cathelco can supply dedicated cathodes which are isolated from the hull Figure 6 15

16 _ + Seachest top Anode Anode The Anodes and the Cathode are isolated from the hull Stainless Steel Cathode Figure 6 Dedicated Cathode Arrangement 3.3 Forms of Fouling not Controlled by Cathelco Systems Seaweed and grass are not affected, and have to be cleared from the intake strainers when they proliferate. Certain algae and green slimes are not affected, but these do not build up and block pipes in the way mussels do, as they require light for growth. 3.4 Treatment of Feed and Process Water The copper (and aluminium or ferrous) ions generated by the CIG process do not carry over with the condensate in evaporative type fresh water generators, or pass through the membranes in reverse osmosis units. The CIG process is approved by the UK Ministry of Health for feed water in potable water makers. While the addition of copper in the same order of magnitude as that already in sea water is enough to prevent transition of shell fish and mollusks from larvae to adults, it will not affect the adult animals. CIG treated water is used in holding tanks for adult shrimp, clams and lobster with no noticeable ill effects. 3.5 Dosage Rates and Anode Life Cathelco engineers will recommend the number, size and disposition of anodes in a new A/F system based on the sea water piping schematic, pump capacities, and the vessel s trading pattern (including port time, fresh water sailing time, and dry docking interval). The current settings, which in turn determine the rate of depletion of the anodes, will be specified to give reasonable assurance of fouling control, but because this is not an exact science, anodes will generally be sized with a margin to allow the user to increase current if some fouling is still experienced. Clearly, when a vessel s main engines are not running there is a significant reduction in sea water cooling requirement, and in the case of port stays lasting over 24 hours, the current settings can be reduced. This reduction can be accomplished manually, by adjusting current to each anode or by a master switch controlling all affected anodes through relays; alternatively it can be controlled automatically through relay(s) activated by contacts in the relevant pump starters. See also Section

17 3.6 System Flushing Procedure During long periods of the Cathelco system being set as not in use we recommend that you use the system flushing procedure. When the pumps are turned off the control panel is set to the not in use setting. During this period there is no flow in the sea chests and copper ions will build up in the isolated area over time. Please ensure that the pumps are regularly turned on for a minimum of one hour per week during down time and the control panel settings set to the in use settings. (See setting page) When the system is in flushing mode a greater concentration of ion rich water will purge the system for a short period of time. This will ensure that the entire system will work efficiently during the whole period. 17

18 SECTION 4 Installing Nano Anodes Nano Anodes These are a lot smaller in size and are designed to fit in confined areas with small flow rates. They come in two different diameters and different lengths depending upon the installation area and flow rates. There are two main types as follows:- Pico Anode 3355 Type Anode with integral cathode 2525 Type Submersible anode & Cathode 2755 Type Submersible Omni Anode with integral cathode Figure 7 Nano Anodes Anode with integral cathode These are fitted with an integral cathode, which allows them to be fitted into plastic strainers where there is no earth return path. A 19mm dia hole is drilled in the top of the strainer. The stud is removed from the top of the anode and inserted from the top strainer lid, the anode c/w neoprene gaskets and insulation washer are screwed on to the stud from the under side. The unit is fitted directly to the strainer lid through a 19mm diameter hole. The strainer should be smooth on the top surface to ensure that the 0 ring fits with a water tight seal to the strainer lid. Anode location The anode assembly should be located on the strainer lid. Ensure that the anode is located inside the strainer basket. It is important that the anode does not touch any metallic components and in certain cases it may be necessary to remove the strainer basket lifting bar. Note. The thickness of the strainer lid plus top insulation washer equals 25mm. If the actual measurement is less than this a smaller washer may be placed between the hexagonal section of the anode mounting stud and the top insulation washer. Ensure that the 0 is fitted in the chamfer in the top insulation washer and in contact with the strainer lid. The brown core from each anti-fouling anode should be wired to MG+ and the blue core should be connected to the corresponding earth return (MG-). For example:- First Anti-Fouling Unit in Strainer 1 (Brown Core) 2BA Eyelet To 2BA set screw +ve to Copper Anode (Blue Core) 3mm Eyelet To top of ve Cathode After switching one, check the polarity of the anodes in relation to the cathode. All anodes are to be positive, relative to a negative cathode. 18

19 4.1.3 Submersible anode These are fully sealed units and the cable used is suitable for use in sea water. They can be either mounted into the top of strainers or submerge mounted inside strainer baskets, especially where deep cylindrical or conical shaped strainer baskets are used. A 32mm dia hole needs to be drilled in a strainer lid or mounting flat to accommodate the anode. The anode should be inserted from underneath and secured with 2 nuts on the top side using a pin spanner Omni anode These are fitted with an integral cathode, which allows them to be fitted into plastic strainers where there is no earth return path. These are fully sealed units and the cable used is suitable for use in sea water. They can be either mounted into the top of strainers or submerge mounted inside strainer baskets, especially where deep cylindrical or conical shaped strainer baskets are used. A 32mm dia hole needs to be drilled in a strainer lid or mounting flat to accommodate the anode. The anode should be inserted from underneath and secured with 2 nuts on the top side using a pin spanner Submersible cathodes These are available where a dedicated earth return path is required, again these can be submerge mounted. A 32mm dia hole need to be drilled in strainer lid or mounting flat to accommodate the anode. Insert the anode from underneath side and secure with 2 securing nuts on the topside Pico anode These are very small anodes for very small strainers. A 10mm dia hole need to be drilled in strainer lid or mounting flat to accommodate the anode. Fit the anode from underneath side and secure with 2 securing nuts and isolating washers on the topside Installation of submersible anodes with nylon mounting / Omni Anodes in strainer lid. The unit is fitted directly to the strainer lid through a 32mm diameter hole. The strainer should be flat with a 60mm diameter machined flat section free from paint and burrs on the top and bottom surfaces to ensure that the O ring fits with a water tight seal to the underneath of the strainer lid. Ensure that the anode is located inside the strainer basket. It is important that the anode does not touch any metallic components and in certain cases it may be necessary to remove or relocate the strainer basket lifting bar and strainer lid lifting bolts. Ensure that the O ring is fitted in the bottom insulation washer and in contact with the strainer lid. 1) Determine the position of the anode mounting and 32mm diameter hole in strainer lid to suit. This is usually the dead centre when only one anode is used per strainer. 2) Fit the anode from underneath and secure with nylon nut using a pin spanner. 3) Fit or weld earth stud to either strainer lid or strainer body and attach earth cable. See wiring diagram in SECTION 11 (or connect to cathode if required). Installation of anodes with nylon mounting for submerged mounting 1) A suitable bracket must first be made and fitted to the strainer basket which must be a minimum of 50mm x 3mm thick. The bracket can be welded or bolted to the strainer basket. 2) Determine the position of the anode mounting sleeve and drill 32mm dia. hole in bracket to suit. This is usually in the dead centre of the bracket. Ensure the anode does not touch any steelwork or other metal objects in the locality 3) Fit anodes as for strainer lid mounting. 4) Lower basket into seawater intake. 5) Fit cable gland, suitable for cable size, in strainer lid. 6) Pass the cable through the gland and secure gland. Do not coil the cable Replace strainer lid. 7) If submersible cathodes are supplied they should be fitted in the same way as submersible anodes. 19

20 SECTION 5 Anodes Installation and Positioning Generally a given installation will have anodes of more than one size and material. The system information in SECTION 1 indicates the type and size of anode at each location. The Cathelco system diagram does not show structural details or the precise location and orientation of each anode. Sometimes the contractor will make working drawings showing such details, but even in those cases careful measurements should be made to ensure that the anodes and sleeves can be installed as shown. In locating anodes the following points must be taken into consideration: For orientation more than 30 º from the vertical, Cathelco should be consulted, see Figure 8. With weld-in sleeves, the clearance for inserting the anode must be its full length including the stud. See Figure 9. With flanged sleeves, the clearance must be more than the distance from the end of the anode to about 30 mm above the top of the cable gland. See Figure 10. Anodes must not be located in a dead space, but as nearly as possible in the direct flow path of the water from the inlet grids to the sea water suction pipes. See Figure 11 In order to prevent uneven burn-off of the anode, structural members must not be nearer to the anode surface than shown in Figure 12. Where this amount of clearance is a problem, Cathelco should be consulted. Before cutting and welding, it is advisable to have the location and orientation agreed to by Cathelco s on-site representative. Most anodes can be mounted up to 30 degrees from the vertical as shown on the right. Shorter anodes may be mounted horizontally after prior agreement with Cathelco. Consult Cathelco if angle is greater than 30 degrees. Figure 8 - Anode Orientation 20

21 The diagram shows the clearance required in the seachest for installing and replacing anodes when using weld-in sleeves. L= Required clearance for installation of weld-in sleeves Figure 9 Clearance for Weld-in Sleeves The installation of flanged sleeve anodes usually requires clear access from above to allow for the use of lifting equipment. L= Required clearance for installation with flanged sleeves Obstruction Seawater out Figure 10 Clearance for flanged sleeves 21

22 Anodes should be mounted in the main flow of seawater from the inlet grids to the seawater suction. Anodes should not be mounted in the dead areas, for example, unused frame spaces or in the top of large seachests where the inlet point is well below. Without grating. Do not mount anode here. Even with inlet grating, avoid mounting anode in this space Seawater Out If possible, mount anode in this space. Figure 11 Mounting Anodes in Direct Flow (Plan View) 22

23 See table below for minimum acceptable distance from structure. Anode Dia./Mounting A B C L 82.5 Weld in sleeve Weld in sleeve DN/JIS100/4 flange min DN/JIS150/6 flange min Cofferdam min anode length anode length anode length Nano anodes 50 min 70 min 50 min n/a The above table applies to all anode installations i.e. sea chest, strainer etc. A = Distance from centre of anode to nearest steelwork. B = Distance across centres of anodes. C = Clearance from bottom of anode to sea chest bottom Min. L = Clearance top of anode mounting to nearest obstruction. Figure 12 Clearance from Structural Members The above are recommended minimum distances. In some circumstances they may be reduced, but it is essential to consult Cathelco before installation. 23

24 5.1 Installation of treatment (electrolysis) tanks The anode treatment tank is made from mild steel. The inside surface of the treatment tank is coated with a rubber lining up to 3mm thick or a coal tar epoxy paint. In order to avoid fire damage and mechanical damage to the rubber lining, welding or any other potential fire risk, work should not be carried out in the vicinity of the tank. It is recommended that the treatment tank is installed as low as practicable in the engine room and should be placed as close as possible to the sea chests. The tank must be securely fixed in a position which allows sufficient height for installation and removal of the anodes. After fabrication of the anode treatment tank, the anodes should be mounted on the lid in accordance with the drawings supplied. An earth return (-ve) (cathode rod) is installed in the electrolysis tank. Use a minimum of 1 earth return lead for each cathode and 1 cathode for every 4 to 6 anodes. 5.2 Painting Cathelco recommend painting all mounting sleeves to the same specification as the seachest or strainer lid to which they are fitted. The only surfaces that should not be painted are those which are in contact with sealing gaskets such as the flange gaskets and top sides of the anodes. All weld-in and flanged mounting sleeves are supplied painted with a weldable primer. 24

25 SECTION 6 Control Panels Modular RS/DD Modular EL/DD Mini EB/CC 4 Way Small Boat EB/SB 2 Way Nano EB/NS Cathelco A/F panels are dust and spray proof to a maximum rating of IP65, and can be located in machinery spaces. The IP rating must be preserved by using spray tight strain relief glands for cable entry. The contractor must make a robust structural frame to which the panel will be bolted. Bolt size and spacing are shown on the panel drawing in SECTION 11 of this manual. The panel should be located at about eye level, with convenient and safe access for adjusting currents and servicing. The door on type EB/** panels, and the whole hinged module section on type EL/**/** panels must be clear to swing out at least 90 degrees. It is highly recommended that EL/DD/ and EL/4D/ type panels are mounted on the horizontal brackets shown on the panel drawing. These give additional support, particularly when the module section is open. Cathelco also recommends gluing a 5 mm thick strip of rubber to the top of the bracket to give greater protection to the front door and mid-section of the panel. The contractor shall punch or drill the control panel gland plate with the correct size holes (or use the pre-punched holes in EB/** type panels) and supply and fit glands to the required standard. In the case of EL Modular Panels with swing-out module sections, care must be taken to leave sufficient length of cable between gland and terminal block to swing the module section through at least 90 degrees. When installing RS Modular Panels, the gland plate must be removed to gain access to the terminal connection block which is attached to the inside of the gland plate. Control panels must be earthed to the ship s structure. Generally the mounting bolts will perform this function satisfactorily. This can be checked by carrying out a continuity test between the panel casing and the ship s structure. After fitting, check that the panel is set for the correct voltage. Type EL and RS Modular panels have a switch inside the power supply module that can be toggled between 115 and 230 volts. Type EB/CC panels have a 115/230 switch accessible from the front and located on the bottom of the PCB board. Type EB/SB and EB/NS panels take either a 12V or a 24V DC supply and are auto-sensing. 25

26 Type EL/DD/** RS/DD EL/4D/** RS/4D EB/CC EB/SB Modular yes yes no no EB/NS 1-2 no EB/NS 3-4 no Input Voltage 220/110 AC 220/110 AC 220/110 AC 24/12 DC 24/12 DC 24/12 DC Max no. Modules 4 per row 4 per row Max Anodes 8 per row 4 per row Max Output Per Anode 2 A 4 A Fuse (Power) 2.5 A or 5A 2.5 A or 5A Fuse (Anode) Weight 3.15 A 25kg+ 6.3 A 25kg+ I.P Rating I.P 55 I.P 65 I.P 55 I.P 65 N/A 4 2 A 2.5 A 3.15 A 5-8kg I.P 65 N/A 4 1 A 5 A 1.6 A N/A A 2.5 A 630 ma N/A A 5 A 630 ma Figure 13 Control Panels 4-4.6kg 2.5-3kg 2.5-3Kg I.P 65 I.P 65 I.P 65 For details of the specific equipment supplied for your installation, please refer to SECTION 1and the drawings which appear at the back of the manual. 6.1 Electrical Installation Cable Sizes and Types Cathelco supplies each anode with a minimum of 1 metre of double insulated single conductor cable (longer if ordered by the client). For ease of identification, cables supplied as part of anode assemblies are coloured as follows:- Anode Type Cable Colour Coding MG (Copper) Red Outer/Red Inner PVC covering OR Grey Outer/Brown Inner PVC covering TC (Aluminium) Black Outer/Black Inner PVC covering OR Grey Outer/Blue Inner PVC covering FE (Cast Iron) Black Outer/Black Inner PVC covering OR Grey Outer/Blue Inner PVC covering Note : For Dual Purpose Anodes, smaller Nano Type and Submerged Anodes refer to drawing for cable specification. Figure 14 Cable Colour Coding 26

27 All other cables in the A/F system are to be supplied by the contractor. Cables and their insulation must be of a type approved by the inspection authorities for their location, voltage and temperature. In order to achieve acceptable voltage drop, and based on not more than four anodes per earth return conductor, Cathelco recommends the following conductor sizes for the anode circuits: Length of cable run/m Minimum conductor DD modules up to 2 amps output. Minimum conductor 4D modules up to 4 amps output. Metric AWG Metric AWG sq.mm 14 4 sq.mm sq.mm 12 6 sq.mm sq.mm sq.mm 8 Figure 15 Cable Supply Sizes Cable for the power supply should not exceed 2.5 sq.mm 2 with a minimum of 1.0mm 2 core. Oversize cables should be avoided, as they are likely to cause mechanical overload on the terminal blocks. For signal circuits from peripherals to relays, 1.5 sq.mm or AWG 16 will generally suffice, regardless of length. 6.2 Cable Installation Proximity to other cables, cable clip spacing, and mechanical protection in vulnerable areas, shall all meet with the approval of the inspection authorities. The Cathelco supplied anode cables shall be connected to the system wiring in water tight junction boxes, located as far above the bilges as practicable. In the case of solid stud anodes, make sure the anode cable is tightly secured to the top of the stud using the 6 mm cap screw. To avoid malfunctioning of the system due to leaky glands or condensation, Cathelco recommends packing the sleeve cavities and junction boxes with petroleum jelly or non-conducting silicone grease. After packing the sleeve cavity and screwing on the safety cap, tighten the gland, making sure there is no mechanical tension on the cable. Cathelco recommends that all cables be tagged. Future troubleshooting can be simplified if a marked up copy of the Cathelco wiring diagram or a contractor s working drawing with the tag numbers identified, is placed in the back of the control panel. This drawing should also show the supply distribution panel number and circuit number. 6.3 Power Supply Each AC panel should have a properly identified dedicated single phase supply circuit, protected by a fuse or circuit breaker. The supply cable shall have three conductors, phase, phase or neutral, and earth. 27

28 The fuse/circuit breaker rating must not be less than the maximum input of the wattage divided by the voltage. In most cases a 10 amp rating will suffice, although 15 amps is commonly the smallest available. In any case, the ampacity of the supply cable must exceed the fuse/breaker rating. DC panel supply cables should be two conductors with an ampacity of 10 amps. Panel Type Power Consumption/ Per Channel (No of anodes) 2 Amp Module 30 VA Per Channel (60 VA Total) 4 Amp Module 60 VA 30 VA CC SB NS 20 Watts Per Channel 12 Watts Per Channel 6.4 Peripheral Circuits Figure 16 Power Consumption In most cases a two conductor 1.5 sq.mm cables will suffice for connecting a peripheral to the corresponding relay in the panel. If Cathelco are not supplying or specifying the peripheral, they should be informed of its specifications. 6.5 Testing Final testing of the system is described in SECTION 9, Commissioning. Before installing hollow stud anodes, the resistance between the anode and the stud should be checked using a multimeter. It should be infinity for a dry anode before it has been fitted in situ. Cable run integrity should be checked before the system is flooded, with the anode supply and return cables disconnected at the panel. Once the anodes are connected, their circuit resistance to earth must be checked using a multimeter only, a meggertester voltage is too high. 6.6 Retrofit Installations When retrofitting a CIG system caution should be taken. There may be a large amount of growth already in the pipework. Once the CIG system is switched on this growth will gradually die and so regular inspection of strainers and coolers is recommended for the first 6 months. This should be taken as a positive sign that the system is working correctly. 6.7 Systems fitted with Current Reduction Relays If the control panel is fitted with current reduction relays which means that when a sea chest is not in use the current to the anodes in that particular sea chest will be reduced. The connections on the back of the panel will be marked for each pump or sea chest/strainer valves. Each Pump/Valve needs to be fitted with a relay N/C Zero voltage. The relays in the control panel will give out 24 V dc, a pair of wires from each set of connectors on the panel needs to be connected to the N/C Zero Voltage relays on the Pump or Strainer / Sea Chest valves. The current needs to be set to the high (in operation setting) when the valve is open or the pump is on. When the valve is then closed or the pump is off then the current to the anodes for the appropriate strainer or sea chest will automatically be reduced by the predetermined amount. 28

29 SECTION 7 Operating & Maintaining a Cathelco A/F System 7.1 Daily Checks Cathelco recommends recording the current readings, or at least deviations, for each anode daily on a log sheet. This will ensure that anomalies can be dealt with promptly, and reduce the chance that crew will forget to adjust from in use to not in use settings. A standard copy of the log sheet can be downloaded from the Cathelco website. All log sheets can be sent to Cathelco for analysis free of charge. They should be ed to aflogsheets@cathelco.com this is important because the record of the current settings will help in determining the cause of any problems that might arise. If one of the current settings is showing zero and cannot be adjusted, or there are any other problems with system, please see SECTION 8 of the manual. If the cause of the problem cannot be found, please contact Cathelco for further assistance by ing technical_af@cathelco.com As part of the daily supervision, check that all the digital display ammeters are working. When an anode has nearly wasted, the corresponding display will start to fall. When this happens, turn the anode current knob back to zero and leave it until the anode renewal. Reset once again at sea after renewal to the previously given current settings. 7.2 Current Settings SECTION 1of this manual gives the recommended current setting for each anode. The effective working of the system can only be determined by inspection and it is suggested that if after 6 months of operation the opportunity to examine a strainer, length of pipe or heat exchanger, presents itself, this should be done. This routine can be repeated at intervals, the current being adjusted accordingly. The seagoing current settings are adjusted manually. If there is evidence of mussel or other marine growth beginning to appear in strainers or heat exchangers, adjust this setting for the copper (A/F) anodes upwards in increments of 0.2 amps until new growth ceases to appear. Each increment should be left set for 30 days before further adjustment up or down. For installations in which current reduction is not automatically controlled by peripherals, adjustment to the not in use settings given in SECTION 1 must be made manually. Cathelco recommends doing this whenever a port stay, with the main sea water circulating pumps shut down, lasts more than 24 hours or whenever a sea chest is not in use. Some vessels such as shuttle tankers may have large ballast pumps running during unloading operations. If the ballast pumps draw from the same sea chests as the main circulating pumps, the current should be left at the in use setting even if the latter are not running. 7.3 Anode Life Since Cathelco has no control over anode current settings after a system has been commissioned, anode lifetime cannot be guaranteed. In the case of new builds at shipyards located in fouling prone areas, it may be desirable to operate the system during the outfitting afloat stage. Owners must takes this period into account when estimating the time to re-order anodes. 7.4 Fresh Water When navigating rivers and lakes (fresh water) for more than a few days, Cathelco recommends switching off the system until the vessel returns to salt water. (See also SECTION 3.2.8) Fresh water will cause the system settings to drop to zero and when the vessel is in brackish water there may also be a reduction in current output. This is because the brackish (less salty) water has a higher electrical resistance than normal seawater. 29

30 7.5 Seawater Supply Management The assumption in determining anode current values is generally that all sea valves, except for high suctions for use in shallow muddy or sandy water, are normally open, and only closed during strainer cleaning. Any departure from this mode of operation may lead to insufficient dosing in some seawater systems. Some operators have found that where dosing appears to be insufficient, and overheating of engines is not a problem, light growth can be stopped by recirculating dosed seawater to the seachests instead of overboard. This can avoid increasing current settings and shortening anode life. 7.6 Anode Change/Replacement Only genuine Cathelco anodes/parts should be fitted. Using anodes/parts supplied by other manufacturers will invalidate the Cathelco warranty. Most anodes are available from stock. Nevertheless it is recommended that Cathelco be given 4-6 weeks notice for supply of replacement anodes. The Cathelco reference, vessel name and anode reference should be quoted when ordering replacements. The system must be switched off before any work is carried out on the anodes. All anodes are sacrificial anodes and will be consumed after a period of time. Seachest mounted anodes must be replaced at every dry docking. Anodes mounted in-board of a sea valve (i.e. in strainers) can be replaced as required. For the majority of installations where a mounting sleeve has to be used, the procedure below should be followed. 1. Slacken the sleeve gland nuts, back off the sleeve safety caps, and disconnect the tail cables at the anode or the junction box as appropriate. Remove the spent anodes using the appropriate box spanner. 2. In the case of cofferdams, the top flange should be removed to allow access. Then the cable should be disconnected from the anode before the whole assembly is removed from the seachest. When removing nuts from the anode mountings, care must be taken to prevent the remaining part of the anode from falling through the seachest, creating a risk to personnel, or damaging the bottom of the seachest. 3. Once removed, thoroughly clean the sleeve cavities and install the new anodes as indicated in Error! Reference source not found. of the manual. Fit new O rings and gland grommets. 30

31 Submersible anodes Cables should be disconnected from the junction box/anode top as appropriate. The securing nuts should be undone as required and the anodes removed. In the case of anodes with integral cathodes, the remains of the copper anode should be unscrewed from the stud and whole assembly removed. After installation, perform the same dry and afloat tests as for a new system installation. 7.7 Routine Maintenance Cathelco anti-fouling systems are rugged, relatively simple, and very reliable if installed correctly. No routine preventative maintenance is required between anode changes. If a Cathelco representative is not present to supervise the anode change, a responsible technician should inspect the panel(s) for cleanliness and check the fastenings, as well as performing commissioning checks/installation tests. Fault finding is dealt with in SECTION 8 of the manual. 7.8 Maintenance of electrolysis (treatment) tank systems To ensure that electrolysis tank systems stay in good working order it is essential that they are cleaned on a regular basis. 1) The air vent should be opened daily to prevent air pockets inside the tank. 2) The tank should be cleaned out to remove anode floc at least once every 2 months including a drain off operation, if necessary, as follows:- a) Turn of main power in control panel. b) Close inlet valve of anode treatment tank and open drain valve. c) Remove hydroxide that has settled inside the tank. 3) The water strainer and flow meter on the sea water flow pipe should be cleaned out to remove anode floc every 2 months. 4) The valves for the not-in-use seachests should be closed and valves for the in-use seachest opened to give appropriate flows to each seachest as required. 31

32 7.9 Anode renewal in electrolysis (treatment) tanks Anodes need to be replaced when there is only a small amount of copper showing below the heat shrink. Replacement anodes are supplied with all the parts that are necessary for replacing them. It is not necessary to replace the mounting sleeves. 1) Switch off the power to the control panel and pump, then close the inlet and outlet valves to the treatment tank. 2) Open the drain valve and air release valve. 3) Empty the treatment tank. 4) Disconnect anode/cathode cables in junction box, if required. 5) If the anodes are flange mounted, remove each anode individually from tank c/w flange mounting. 6) If anodes are weld-in sleeve design, remove the whole tank lid. 7) Loosen cable gland and remove each lid on each sleeve. 8) Remove cable, undo nuts and remove old anodes. 9) If necessary, clean flat surfaces and inside sleeves to remove any unwanted debris, etc. 10) Install new anodes in reverse order making sure the neoprene washer is on top of the anodes and makes a seal with the underside of the mounting sleeve. See anode replacement sheet for correct torque setting of anodes. 11) The tank should be thoroughly cleaned inside. 12) The sleeve lids and tank lid should be replaced in the reverse order and secured. Replace gaskets if necessary. 13) Reconnect the anodes inside junction, if necessary. 14) Close drain valve and air vent valve. 15) Open valves, restart pump and turn on control panel. 16) Open air valve to release any trapped air until water appears, then close. 17) Check current settings on control panel are correct according to the manual. 32