An Alternative to Tracing Impeller Parts!

[s/v Jedi]

Hi all,

I hope that I'm the only one that had to trace impeller parts (after it failed) into the heat exchanger etc but I'm afraid not.

There's this long time solution of installing a strainer between the impeller pump and the heat exchanger, which I tried. The problem is that it gets clogged with other nasty stuff quickly, leading to other disasters.

So, we just installed a new genset and this time I gave it some more thought and came up with a strainer with a self-made PVC insert instead of the standard mesh. See attached photo's.

The strainer I used is a Shureflo model with 3/4" threaded connections. You must at least use this heavy duty model and not the ones with molded hose barbs (been there, those barbs collapse with major leaks as the result). The original mesh screen is stainless steel and 1-1/4" diameter. I still had some thin wall PVC pipe and using some of my artistic abilities (not! ;-) and drill made the insert as can be seen on the photo's. The biggest holes are still smaller than the channels in the heat exchanger.

Also: make the insert just a little shorter than the original mesh screen, so that it is sure the strainer bowl screws on all the way. The PVC insert will not give like the original screen, leading to possible leaks otherwise. There's about 1/4" room for making it shorter without problems but I decided on even less than 1/8".

I had to use new pieces of hose with steel reinforcement to be able to make the bends without collapsing the hose. I installed the strainer as low as possible and right next to the pump. The new Northern Lights genset had a nice bracket for holding the drain-hose for the oil sump which is used for both the strainer and drain hose now. With short pieces of hose, the strainer must be attached (and move with) the engine.

We just put the first hour run time on the genset and it works perfectly. The PVC insert even turns around slowly with the rotating water flow through the strainer, giving another indication of waterflow as a bonus.

Hope that the idea is of use for someone!

ciao!
Nick.

[Chief Engineer]

I am impressed.......Ah....the mind of a sailor.......all those hours at the tiller give ya time to think

[speciald@ocens.]

Good idea but more frequently I have found blades stuck in the outflow of the pump housing so they would not have made it to your trap.

[s/v Jedi]

Originally Posted by speciald@ocens.

Good idea but more frequently I have found blades stuck in the outflow of the pump housing so they would not have made it to your trap.

Oh yes, those are the easy parts. But in most cases what you find there is not all that is missing from the impeller. I only had that once and think it was a manufacturing defect of the impeller. After fitting the puzzle of the recovered pieces together, parts are missing and they often are big enough to not fit through the heat exchanger. Well, you don't know actually, because a part that's missing might be broken up in several pieces that would go through the heat exchanger. But you don't know that. With the strainer, you can be positive that the heat exchanger is clean.

It's cheap and easy to do; I spent less than an hour on the project and most of that was trying to drill a nice pattern in the PVC which is totally not useful ;-)

cheers,
Nick.

[Lepke]

Nicely done addition! I may copy your design for my generators. My main Detroit Diesels have easy to clean exchangers and I've never had an impeller fail.

[Jd1]

Never mind the strainer ... I had to put on my heavy duty shades and I still got blinded by that immaculate and VERY white genset ! I have no idea how you do it but holy cow !!!!