Hydraulic Reservoir Help

bjcsc · Oct 22, 2008

I'm setting up my reservoir for my 3pt. hydraulic setup. I bought a 30gal tank. On the top, it has two holes. One of which is for a filter/breather and I recognize it, the other I don't recognize. It is the same type of hole, but 1 3/8" Diameter with three holes 1.5" BC. What goes there?

It has 1 1/4 FPT inlet on one side and same size outlet on the other. The centers of those fittings are 9" from the top of the tank. It also has two 3" FPT holes in the lower rear corners on each side, the centers of which are 4" from either the back or the bottom (probably originally fitted as cleanouts). Would you use one of the higher 1 1/4" fittings to feed the pump (21 GPM 3000PSI) or would you use one of the 3"? I'm leaning towards the 3"...

john_bud · Oct 22, 2008

I am guessing here (a picture would be worth about 950 more words), but the extra hole on the top is probably for filling.

I would draw to the pump as low as possible, but would baffle it or screen it with ss mesh, so it does not draw any trash. You also ably will want to make the return to tank be smooth so it does not form bubbles.

bjcsc · Oct 22, 2008

I can post a pic of the fittings later tonight. The tank has a nice internal baffle. I can get a 3" MPT 100 mesh screen rated at 50+GPM with a 3PSI bypass that has a 1 1/2" FPT outlet. That's what I would use if I use the lower hole. I'm not sure what you mean by the return being 'smooth'...Anyway, I'll post a couple pics when I get home...

kthompson · Oct 22, 2008

bjcsc, I like your flag. Sort of jealous.

Are the 1 1/4 ports labeled as inlet and outlet? It is my opinion John is correct. kt

bjcsc · Oct 22, 2008

kthompson said:
bjcsc, I like your flag. Sort of jealous.

Are the 1 1/4 ports labeled as inlet and outlet? It is my opinion John is correct. kt

Hey neighbor, thanks! So where are you? Hemingway? Nothing is labeled, but the 1 1/4" ports are in the normal position for inlet/outlet.

bjcsc · Oct 22, 2008

OK, here are the pics. Pretty self-explanatory, but ignore the two 3/4" fittings on the top as I can easily plug those. You can see the 2" hole for the filler/breather and it is sized to fit the standard filler/breather. The opposite side is set up just like the one you see and then there is a 3/4" on the bottom for a drain...

Farmerford · Oct 23, 2008

You are on the right track with the suction strainer with bypass valve in one of the 3" holes. That will keep large particles (150 microns or so) out of the pump inlet. Consider a suction gauge at the pump inlet to tell you when the screen is clogged and the bypass opens.

Return to the tank should be through either 3/4" side hole. If built properly the baffle should be between the 3" outlet and the 3/4" inlet (regardless of the combination you choose). The baffle on a properly sized tank allows the incoming fluid to slow down and some particles will actually settle out before the fluid makes it to the outlet side. The baffle should run from the bottom of the tank up to a few inches below the lowest allowable fluid level. There should be no openings in the baffle below the top. That way, fluid from the inlet side has to flow up and over the baffle to get to the outlet side. One often sees baffles with through holes near the bottom, but that defeats the primary purpose of keeping the sediment that settles out on the inlet side away from the outlet to the pump.

The inlet to the tank should always be below the fluid level so that the incoming fluid is not spraying through the air and creating bubbles in the fluid. The best tanks have a diffuser on the inside of the inlet port (sort of like on a sink faucet) to break up the solid stream and reduce the agitation of the fluid.

I can't guess what the hole with three mounting screws is. Some tank mounted return filters use a three screw attachment, but I think the hole would be larger than 1 3/8".

If you have not purchased your return line filter, consider getting one with a bypass pressure of 40psi or so and a pressure guage to tell when the filter is clogged (and therefore fluid is bypassing the filter). The filters rated 10 micron "absolute" (Parker among many others has them) do a much better job than the 10 micron "nominal" filters. They cost two or three times the 10 micron nominal filters, but provide much more protection for the pump.

How about some pictures of your project?

bjcsc · Oct 23, 2008

Thanks farmerford. I don't have any pictures yet - just parts! But I'm pretty much following your lead, with the exception of the pump. The Prince PTO pumps won't give me the pressure I wanted (they are 2250PSI max) so I am using a speed increaser ( 1:5.51 gearbox) and one of Prince's other pumps to get 3000PSI. My reservoir baffle is setup exactly as you describe (nice baffle). The side ports are 1 1/4", not 3/4" as you stated (and you were probably wondering if they were large enough) so I am good there. I suppose I'll just make a plate with an o-ring to block that small top hole...

Thanks for the heads-up on the absolute vs. nominal filters. I will definitely be going that route regardless of increased cost; They're still cheaper than the pump and motors I'll be running! I am planning on using a suction gauge for exactly what you described. I plan on running 3 gauges: suction vacuum, system (work line) pressure, and return line pressure.

I should get some build time in this weekend, but it will be awhile until I have anything picture-worthy. I'll definitely post pics when I take them...

john_bud · Oct 23, 2008

Sounds like you are on it.

By "smooth" I was meaning that the fluid shouldn't go pouring in and splashing about making foam. Just a nice smooth return so the potential gunk can settle out and not get stirred up.

jb