Flexible Pipe Connections - Wartsila ?31DF Series Product Manual

5. Piping Design, Treatment and Installation
Pipes are pickled in an acid solution of 10% hydrochloric acid and 10% formaline inhibitor for
4-5 hours, rinsed with hot water and blown dry with compressed air.
After acid treatment the pipes are treated with a neutralizing solution of 10% caustic soda
and 50 grams of trisodiumphosphate per litre of water for 20 minutes at 40...50°C, rinsed with
hot water and blown dry with compressed air.
Great cleanliness shall be approved in all work phases after completed pickling.
5.8

Flexible pipe connections

All external pipes must be precisely aligned to the fitting or the flange of the engine to minimize
causing external forces to the engine connection.
Adding adapter pieces to the connection between the flexible pipe and engine, which are not
approved by Wärtsilä are forbidden. Observe that the pipe clamp for the pipe outside the
flexible connection must be very rigid and welded to the steel structure of the foundation to
prevent vibrations and external forces to the connection, which could damage the flexible
connections and transmit noise. The support must be close to the flexible connection. Most
problems with bursting of the flexible connection originate from poor clamping.
Proper installation of pipe connections between engines and ship's piping to be ensured.
● Flexible pipe connections must not be twisted
● Installation length of flexible pipe connections must be correct
● Minimum bending radius must be respected
● Piping must be concentrically aligned
● When specified, the flow direction must be observed
● Mating flanges shall be clean from rust, burrs and anticorrosion coatings
● If not otherwise instructed, bolts are to be tightened crosswise in several stages
● Painting of flexible elements is not allowed
● Rubber bellows must be kept clean from oil and fuel
● The piping must be rigidly supported close to the flexible piping connections.
5-6
Wärtsilä 31DF Product Guide
DBAE248994