Chapter 13-CONDENSERS AND OTHER HEAT EXCHANGERS 



making chemical chloride tests. There are four 

 major causes of a salty condenser: 



1. Leaky tube(s) in the condenser. 



2. Make-up feed tank salted up. 



3. Low pressure drain tank salted up. 



4. Leaky feed suction and drain lines which 

 run through the bilges. 



Each of the aforementioned possibilities must 

 be investigated to determine the source of the 

 contamination and its elimination. 



If it is determined that there is a minor leak 

 in the condenser and the ship's prospective ar- 

 rival time is less than 24 hours, the affected plant 

 will probably be continued in operation. Isolate 

 the condensate system, and limit the number of 

 boilers on the engine involved. When operating 

 under these conditions it will be necessary to 

 blow down the boiler(s) as necessary, to keep the 

 boiler salinity within the specified limit. How- 

 ever, if the leak is serious, secure the plant and 

 locate the leaks. 



If leaky tubes are found, they must be 

 plugged so that the condenser can be kept in 

 service. Plugs, whicharefurnishedby the manu- 

 facturer, should be driven into the tube ends with 

 light hammer blows. If it becomes necessary to 

 plug tube sheet holes after a tube has been re- 

 moved, a short section of tube should be expanded 

 into the tube hole before the tube plug is inserted; 

 this will protect the tube holes from damage. 



Plugged tubes should be renewed during the 

 next shipyard availability if the water chests are 

 removed for other work; or if more than 10 per- 

 cent of the tubes are plugged, a retubing request 

 should be submitted, via the type commander, to 

 NavShips. 



For the procedure in locating and plugging 

 leaking condenser, tubes, refer to either the 

 manufacturer's technical manual for the specific 

 equipment or chapter 9460 of NavShips Technical 

 Manual. 



AIR EJECTOR ASSEMBLY 

 CONTROL AND SAFETY 



In order to provide for continuous operation, 

 two sets of nozzles and diffusers are furnished 

 for each stage of the air ejectors. Only one set 

 is necessary for operation of the plant; the other 

 set is maintained ready for use in case of damage 

 or unsatisfactory operation of the set in use. The 

 sets can be used simultaneously when excessive 

 air leakage into the condenser necessitates 

 additional pumping capacity. 



Before starting a steam air ejector, the steam 

 line should be drained of all moisture; moisture 

 in the steam will cut the nozzles, and slugs 

 of water will cause unstable operation. 



Before cutting steam into the air ejectors, 

 make sure that sufficient cooling water is flow- 

 ing through the condenser and that the condenser 

 has been properly vented. 



The loop seal line must be kept airtight, an 

 air leak may cause all water to drain out of the 

 seal. 



If it is necessary to operate both sets of air 

 ejectors to maintain proper condenser vacuum, 

 air leakage is indicated. It is more desirable 

 to eliminate the air leakage than to operate two 

 sets of air ejectors. 



Unstable operation of an air ejector may be 

 caused by any of the following: the steam pres- 

 sure may be lower than the designed amount, the 

 steam temperature and quality may be different 

 than design condition, there may be scale on the 

 nozzle surface, the position of the steam nozzle 

 may not be right in relation to the diffuser, or 

 the condenser drains may be stopped up. 



Difficulties due to low pressure are generally 

 caused by improper functioning or improper ad- 

 justment of the steam reducing valve supplying 

 motive steam to the air ejector assembly. It is 

 essential that DRY steam at FULL operating 

 pressure be supplied to the air ejector nozzles. 



Erosion of fouling of air ejector nozzles is 

 evidence that wet steam is being admitted to the 

 unit. Faulty nozzles make it impossible to oper- 

 ate the ejector under high vacuum. In some in- 

 stances, the nozzles maybe clogged with grease, 

 boiler compound, or some other deposit which 

 will decrease the jet efficiency. 



DEAERATING FEED TANK 

 CONTROL AND SAFETY 



During normal operation, the only control 

 necessary is maintaining the proper water level. 

 (On some of the newer ships, this is done with 

 automatic control valves.) If the water level is 

 too high, the tank cannot properly remove the 

 air and noncondensable gases from the feed 

 water. A low water level may endanger the main 

 feed booster pumps, the main feed pumps, and 

 the boilers. 



Deaerating feed tanks remove gases from the 

 feed water by using the principle that the solu- 

 bility of gases in feed water approaches zero 

 when the water temperature approaches the boil- 

 ing point. During operation, steam and water are 



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