11-27-2011 11:20 PM
We are planning to add some additional fuel filtration (Racor Turbine 1000s) before our CAT C27:800 genset. The Racors have SAE ORB input connections. After much time spent searching the web, I am having difficulty locating adapter fittings that meet the Cat requirements of no zinc content. From the A&I guide "Valves and fittings may be cast iron or bronze (not brass). Zinc plating or zinc, as a major alloy should not be used with diesel fuel due to instability in presence of sulfur. The sludge formed by chemical action is extremely harmful to engines internal components." Most of the adapters (preferably to NPT) seem to be steel with some sort of zinc plating (usually specified as zinc,Trivalent Chromium Zinc, zinc phosphate, or unspecified). The only other option I have found is stainless steel with their 10 times higher cost. Is that what we need to use? Are there any platings that are OK? What does CAT recommend? What are the fittings on the fuel lines on the engines? What are people using?
Thanks for your help,
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11-28-2011 07:36 PM
My opinons are following:
1. Racor is manufactured by Parker who is very professional in this field and CAT supply Fuel/water sepearetor in3500 series from Racor;
2. Parker would consider what kind material is available to satisfy the application condition;
3. In Fuel system, we use black iron pipe, steel tube, stainless steel pipe and matched connectors;
11-28-2011 11:31 PM
I think times have changed a bit since that guideline was published, but a few things to keep in mind, at least based on my experience.
10 years ago there was enough sulphur and other contaminents in normally available diesel fuel that zinc contamination could be a problem. Adding to that was crappy cheap fittings from developing countries that had poorly applied coatings that could easily come off in service at normal fuel flow rates.
Most CAT, Parker, Aeroquip fittings (adaptors and hose fittings) are coated with a zinc containing material, a quality part well made and fininshed has never been a problem even with higher sulphur fuels like marine DFM as far as I know. Poorer quality fuels can always attack fuel piping material, and in some cases black iron is not acceptable. Galvanized pipe and fittings are never a good choice for fuel piping in my opinion. But clean coated steel tube and quality coated steel fitings have been used in many installations with no problems, on CAT and many competitors products.
If your in the USA or some place else with strict emissions rules and only ULSD fuel, and quality parts are available from reputable suppliers, then you shouldn't have any problems.
My two cents worth, Mike L.
12-02-2011 08:19 PM
Thank you both for your replies. Looks like I was worrying about something I didn't need to.
MikeL - I appreciate reading your "two cents worth" posts. Thank you for sharing your experience backed knowledge with the rest of us.