Air cooler T 28-1/7

Transcription

1 Air cooler Structure Equipped with feed water heater (Horizontal-type) 6 Remark): There are 2 types of air cooler that are equipped with and without feed water heater. Tools : (The construction varies depending on extracting 1 Extracting tool Components: 1 Roller plate Rail Eye bolts a No. Name of article Check item 1 Casing Take care about high temp. 2,2a Element Take care about broken tube, salting, sea water flow & outlet temp. 3 Header (gate side) For A/C use 4 Header Coated inside to prevent damage. 5 Flange 6 O-ring Replace by a new one. 9 Gasket Ditto 12 Header (gate side) For feed water heater 13 Header 14 Flange 15 O-ring Replace by a new one. 16 Gasket Ditto 17 Gasket Ditto 18 Gasket Ditto 19 Side plate 20 Eye plate T 28-1/7

2 1-1 Air cooler list No. ENG-NO Cyl. Ship Air Cooler Eng.Type Ship Yard No No. Manufacturer Type No. Heater RTA84T IHI Kure 3030 Kawasaki Heavy Industries SGHV740S-B1 4J368-C1,C2 SGHV740S-B1 4J368-H1,H2 Co., RTA84T IHI Kure 3049 do SGHV740S-B RTA84T IHI Kure 3053 Suction Gas Engine Mfg. SWPX-193/R152, 94-A561,A562 SHL6-102/R H031,H032 Co., SWPX-365/R152/4 94-A563,A RTA84T IHI Kure 3069 do SWPX-304F/R220, 95-A617,A618 SHL6-175/R H010,H011 SWPX-802/R220/4 95-A629,A RTA84T SHI do SWPX-521/R150/ A615,97-A616 Yokosuka RTA84T IHI Kure 3093 do do 98-A499,98-A RTA84T IHI Kure 3101 do SWPX-1181F/R220/4 98-A045,98-A046 SHL6-97/R220/4 98-H008,H RTA84T IHI Kure 3102 do do 98-A136,98-A137 SHL6-97/R220/4 98-H015,H RTA84T IHI Kure 3105 do do 98-A300,98-A301 SHL6-97/R220/4 98-H020,H RTA84T IHI Kure 3104 do SWPX-845/R A621,98-A622 SHL6-137/R H043,H RTA84T IHI Kure 3106 do SWPX-1181F/R220/4 99-A091,99-A092 SHL6-125/R H002,H RTA84T IHI Kure 3109 do CH6W-633/R220/2 99-A186,99-A187 SHL6-129/R H008,H RTA84T IHI Kure 3110 do do 99-A275,99-A276 SHL6-129/R H013,H RTA84T IHI Kure 3119 do CH6W-949F/R220/4 99-A396,99-A397 SHL6-135/R H019,H RTA84T IHI Kure 3122 do do 99-A479,99-A480 SHL6-135/R H021,H RTA84T IHI Kure 3125 do CH6F-1284F/R220B/4 00-A212, RTA84T IHI Kure 3126 do do 00-A318, RTA84T IHI Kure 3124 do CH6W-949F/R220/4 00-A123,124 SHL6-135/R H001,H RTA84T IHI Kure 3127 do CH6F-1284F/R220B/4 00-A410, RTA84T IHI Kure 3128 do do 01-A020, RTA84T IHI Kure 3154 do CH6F-1352F/R220B/4 SHL6-150/R220B/6 01-A122, H004,H RTA84T NKK 222 do CH6F-1589F/R220B/4 01-A231,01-A RTA84T NKK 225 do do 01-A480,01-A RTA84T IHI Kure 3159 do do 01-A446,01-A RTA84T IHI Kure 3160 do CH6F-1015/R220B/4 02-A083,A RTA84T IHI MU do CH6F-1431F/R220B/4 02-A241,A Kure 84T 28-2/7

3 1-2 Outline of structure 2. Check item 2-1 Periodic checks At time of engine patrol The feature of air cooler for RTA84T type engine is as follows. Flow direction of scavenging air: Air passage in horizontal (left and right) direction (Vertical-type air cooler) Less channeling in tubes even in small quantity of water Feed water heater: With or without heater Main engine can be run without supply of feed water Cooling medium: Fresh water or seawater In case of seawater, limits on minimum flow and maximum outlet temperature due to salting 1) Check the jointing face of casing (inlet side) and air-duct for leakage of scavenging air. (Caution: Be cautions about the scavenging temperature that normally it reaches higher than 140 C.) Measures: Tighten the bolts. Change packing during repair at the dock. 2) Ensure that a small amount of seawater (fresh water) flows all the time from the air vent. 3) Check the scavenging differential pressure before and after air cooler (the degree of element contamination). 4) Check the gasket and connecting pipe flange in the cooling water chest for leakage of seawater (fresh water). 5) Check the relief valve of feed water heater. 6) If drain from the air duct increase suddenly, the tube of air cooler is in danger of being broken. 84T 28-3/7

4 2-2 Cautions in operation 1) Take care about the followings so as to avoid scales accumulation in the tubes of air cooler. Kinds of scale Soft scale: Deposits of calcium carbonate (CaCO3) and magnesium hydroxide (Mg(OH)2 ) of seawater. Such deposit is not adhering usually to tube walls, but once dried, adheres to them and difficult to remove. (The wear and loss of anti-corrosion zinc causes similar phenomenon with the tubes.) Hard scale: The calcium sulfate (CaSO4) in seawater deposits and adheres to tube walls. Under a certain temperature continue, the tubes get blocked in a short time. So take care in controlling the temperature of cooling seawater. It is difficult to remove them chemically and/or mechanically. 2) Never use the feed water heater at the pressure exceeding maximum working pressure. 3) When seawater is leaking from a broken tube, provide blind plugs in the broken tube, as soon as possible. At the same time, check inside the scavenging space, then remove salt, and clean them with fresh water. 4) Control the air temperature of air cooler outlet by following procedure. Fully open the seawater outlet valve of air cooler. Fully close the seawater by-pass valve of air cooler. Adjust the air outlet temperature by control valve for circulating valve of seawater outlet. 5) Carry out the air vent for seawater line of air cooler at delivery from the port and at checking of M0 system, in order to prevent remaining the air in these lines. 6) Take countermeasures of corrosion at cooling seawater side. (Check the conditions of consumable Zn-plate etc. Correctly operate the MGPS, Fe-ion generator and supply unit of FeSO4 for countermeasure of corrosion at cooling seawater side. 7) Always confirm the tendency of differential pressure between air cooler inlet air pressure to outlet one, which is measured by manometer, in order to prevent contamination and blockage of cooler airside. 84T 28-4/7

5 2-3 Maintenance at dock 2-4 Investigation of air cooler renewal Check the protective metal: Every 3 ~ 6 months Inspection of painting / coating : 1 time / year 8) Check the protective metal at regular intervals, and renew it if necessary. 9) Take care not to damage rust-preventive coating (neoprene, hyperone, tar-epoxy, etc.) of the inner face of header. And any damage is discovered, repair it without delay. 10) When stopping the engine for a long periods, drain cooling seawater (include fresh water) inside air cooler. 1) As standard at the repair-dock, also considering the maintenance results of the air-coolers, to be unloaded this air-cooler and carried out overhauling and cleaning. At this chance, carry out the cleaning / inspection of both cooling water side and air side, also pressure test the leakage of cooling water side. 2) In the case that the erosion of cavitations etc. was discovered on the inlet side of cooling pipe with the inspection of the air cooler, insert the insertion tube (in case of round tube) in order to prevent the erosion 1) Grasp the condition of air cooler by periodic maintenance / inspection. 2) Make a proper maintenance plan according to the above conditions of the air cooler. 3) In the case that the operation point is not able to obtain the cooling ability of requiring in a short time in spite of after maintenance, consider renewal of the air cooler. Confirm the specification / capacity of the air cooler, and grasp the relation between the blockage rate (number) of tube and cooling ability. 3. Overhaul / reassembly 2) Retightening the bolts when scavenging air leakage happens. Just after overhaul and reassembly, air leak used to occur. 3) Replace the gasket and O-ring by new ones when the header is overhauled. And tighten the bolt clockwise (in the order of 12:00-6:00-3:00-9:00 of clock) 4) Ensure that there are no paint and oil sticking to the surface of protective metal and threads. 84T 28-5/7

6 3-1 Cleaning on air side Judging criterion for cleaning; To be cleaned before the maximum differential pressure reaches 300mm Aq. Cleaning method: 2)Cleaning by compressed air 3)Cleaning by steam Remove oil contaminated stuff with steam (3 ~ 7 kg/cm², 150 C) 4)Chemical cleaning (consult with the cleaning maker.) When airside is washed by the chemical, the stain of the upper tube falls to the lower tube by an insufficient washing, then the stain accumulates, and sometimes causes the blockage in the airside. Never heat the cleaning agent higher than 75 C. The cleaning time differs depending on the type of cleaning agent and the condition of dirt. After cleaning is finished, wash the tubes with fresh water to neutralize them. Confirm that the airside is not choked. 3-2 Cleaning on water side From the viewpoint of which the cooling pipes are blocked with salt, periodically carry out the washing by the brush or chemistry. Cleaning method: 1) Cleaning with a brush Do cleaning with a nylon brush (tool), during wet condition of inside the tubes. 2) Chemical cleaning (cooling effect cannot recovered with a nylon brush cleaning.) Improper chemical cleaning causes damages to the tubes and the life of equipment to be shortened remarkably, consult with the cleaning agent supplier. It is advisable to fit a water chest to the air cooler and to circulate chemicals. The cleaning effect increases with the rising temperature, but the temperature must not exceed 75 C. From the viewpoint of which the cooling pipes are corroded and broken, the medicine density that uses it for the chemistry washing is lowest density which is written in the instruction manual of medicine maker. 84T 28-6/7

7 4. Failure sample 1) Deposit of salt inside the scavenging space due to broken holes of air cooler. 2) Blocked tubes due to salting. 3) Water and air leakage due to aging of o-rings and gaskets 5. Technical information Service information DUQ1-059E Preventing maintenance against clogging of scavenge air cooler 84T 28-7/7