Shaft seal water feed

[Matthew]

Hello guys!

I did replace shaft seal for new one,similar like PSS system,and have some worries about seawater cooling for shaft seal.

It is a sailboat,it has small Yanmar engine in it,and i did found for me perfect spot for connecting hose to shaft seal,and did put also small valve on this pipe,so i can close it when replacing impeller or other works.

Connection is on pipe which goes from seawater pump to heat exchanger. But engine lies just bit under waterline,or in same line,and it has syphon breaker of course.

Should i change this water feed,because water is coming from shaft seal when i open it,i did put also small valve on carbon stator on shaft seal,so i dont flood the engine?

Thanks a lot for your help!

Topic

[Bill Desmarais]

Tony’s crew installed the 3/8s nipple fitting for the water feed to the PSS shaft on the distal (aft) end of the heat exchanger. Easy enough to braze a nipple into the bronze end cap and it’s a short piece of hose from there to the shaft seal nipple.
The water feed is behind the dry riser.
One advantage is the cooling water has passed through the whole SWAC first for max engine cooling before being shunted off to wet lube the shaft seal?
And the SMX custom dry riser to downhill mixer using gravity to drain will disperse the raw water flow perfectly helping to keep the exhaust gases nice and cool and the turbo 100% dry !.

[Tony Athens]

In the big scheme of things, VERY LITTLE water is needed to cool/lube, or what ever you want to call it, a face type water seal or any type of shaft-log seal ..

Yes, that is a relative statement, but for a real number, it you had 2-3 PSI in the 3/8″ hose feeding the seal , that would cover any type of seal used in boats discussed in the type of forums would be more than sufficient…………………………I prefer lower pressures ( 1-2-ish psi max) , but a 100% reliable feed.That is the key.

PSS seals (and most others types) DO NOT need a feed at all in hull speed boats..

[pwrobert]

Another thought

Sometimes the water pressure is too high coming full blast through the shutoff valve to the shaft seal. You have to “play” with the valve a bit and close it until the leaking stops when you are running at WOT. Then leave it there and possibly secure the valve arm so it doesn’t get accidentally closed all the way. The PYI people state that the water pressure should be kept below about 10 pounds..
On my 6BTA 370’s the valve is barely opened as the 1730’s put out a tremendous amount of water and pressure.

[Matthew]

This is not a knock off,this company exists from end of 19 century in Europe,good quality parts,not copy nor nothing.

Guardianage company wants that i install water feed anyway,i will go with Y-piece from syphone breaker,easiest way to do it probably,so i dont waste more time.

[Rob Schepis]

Matija wrote:

This shaft seal is similar like PSS with carbon stator,and manufacturer sudgest to make a water feed to seal.

It sure looks like a PSS knock-off, copy or ??
For a PSS install on your boat a water feed would not be required, just a vent line to keep the unit from becoming air bound.

1 user thanked author for this post.

Bill Desmarais

[Matthew]

Hello Tony.

This shaft seal is similar like PSS with carbon stator,and manufacturer sudgest to make a water feed to seal.

I will post photo from seal itself,and other water pick up point from Y-piece installed near from syphone breaker. I like more water pick up point there from seawater pipe after seawater pump,because it comes always cold water.

[Tony Athens]

On a very “slow vessel” with the shaft seal below the water line that probably can be measured in feet & inches, why would you even need a water feed?

Looks like a Lapsedrop seal? Have you looked into that ?

Tony

[Author]

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