Solenoid valves for marine diesel application

[KOstratavarius]

Just found these forums...WOW! What a resource!

I am upgrading the fuel delivery/filtration system on my 32' Grand Banks trawler, which is powered by the venerable Ford-Lehman 120 diesel. The plan is to install the usual dual Racor filters (I will use the 900MA type), but instead of manual ball valves to select the filters, my plan is to use solenoid actuated valves, which will allow me to switch filters from the helm, thereby eliminating the dreaded trip into the engine room in rough seas, to switch filters, which is often the time when the filters are likely to clog and require switching. Leaving the helm under adverse sea conditions is not something that I wish to experience.

I need help selecting the proper solenoid valves. Safety is my primary concern. Do I need to use explosion proof units?
I understand that uncompressed, ambient temperature diesel vapors are not explosive, but I want to make absolutely certain that I select the proper units.
I have seen valves that state they are "compatible with diesel fuel", but I suspect this is more related to durabilty of the seal material (viton, buna-n, flourocarbon, etc.).

I hope to find units that require an activation voltage of 12VDC, but these seem to be a rare breed. Most are 24VDC or AC, which I could live with if necessary.

I look forward to your comments and suggestions, sources of supply, etc.,

Tom

 

[IceStationZebra]

I don't have any experience with the exact type of valve you are looking for, but I'll throw in my 2 cents.

- "I have seen valves that state they are "compatible with diesel fuel", but I suspect this is more related to durabilty of the seal material (viton, buna-n, flourocarbon, etc.)." I would agree with this. Normally the coils are sealed and they should only see occasional oil/fuel/water splashing. I would look for a coil that uses either a sealed integrated connector or flying leads so you can make a sealed connection. DO NOT use spade connectors, they are not sealed and will corrode.

- I would also be concerned about the relay that will power this valve. It needs to be rated for continuous duty at elevated temperatures. Solid state would be nice, but again it should be sealed from water.

- Make sure that the wires to the control switch are large enough to minimize the voltage drop. You might also consider rigging up a light near the helm that is powered off of the relay output, that way you know everything is working. And don't forget to put a fuse in the circuit.

- If you wanted to be super conservative you could rig up some manual bypass valves in case the electric valve goes bad.

ISZ

 

[GregLocock]

Why not rig a mechanical, vacuum, pneumatic, electrical or hydraulic actuator on your current valves?

Anyway, somebody must make an electric diesel cut-off valve. Well, lookee here, these guys do even if they don't want to sell you one...

http://www.tgk-jp.com/english/e_seihin_morter.html#n05

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[pauljohn]

My advice would be don't do it.
Hand controlled valves are near 100% reliable, any other types are not. Better the 'dreaded trip to the engine room' than the dreaded sound of no engine at all in rough weather and the dreaded radio call of help to the coastguard!

I always visit the engine room regularly ESPECIALLY in rough weather. Makes sense to take a quick peek just to make sure everything is where it should be.

 

[KOstratavarius]

Thanks guys.

Just to give a few more details of my proposed system, if I might.
The original, single Racor fuel system, which has worked flawlessly for over ten years, will be left intact, and will always be there as a back-up system. The "new" dual filter system will be slected or deselected by maunal valves, and will tie into the original system just beyond the original single Racor 500, with a manual valve on this end as well. All (3) of the solenoid valves are normally open types, so in the event of a failure, filtered fuel will continue to flow to the engine, and I can switch back to the original system if so desired.
The new system will have it's own Walbro fuel pump, which allows the dual filters to be used for fuel polishing, while underway, if desired, which to me, is the best time to polish fuel....when the fuel in the tanks is sloshing around.
Your cautions about the continuous duty relays, proper gauge wiring, spade connectors, and indicator lights are all well taken, indeed. In addition, there will be a digital vacuum gauge at the helm to keep track of filter condition.
All helpful comments....Thank You!

 

[Fabrico]

You could also leave them working in parallel, all or some of the time.

If it must be done, I'd second the idea of remote actuation of a manual type valve.

 

[IceStationZebra]

I just had a thought - what about the fuel valve from a 1 ton diesel pickup with dual tanks? Its made for 12vdc and continuous duty. ISZ

 

[KOstratavarius]

That's an idea, but the trick seems to be finding valves that are normally open, with 1/4" NPT ports. I'm guessing the truck valves are NC, 1/8" NPT. From my searches, the vast percentage of these valves are of the NC variety, as you might expect.
I'll do a little googling and see what turns up.

 

[starspangled]

I'm no expert on any of this but: Wouldn't you be better off to never shutoff the fuel 'Main'? Instead open an additional bypass to the second filter when rough seas are encountered? No filtration loss, no chance of defueling, and just an extra failsafe measure to insure full fuel flow, properly filtered, under adverse conditions. Could be reset as needed.

Seems a high quality brass ball valve could easily handle the task, with a solenoid fired lever linkage. There are heavy hitting solenoids used for 'door poppers' by some of the custom car crowd which are 12VDC, very strong, reliable and fairly inexpensive.

Starspangled