ian:
sound good that it is coming together.
-pumps. Barnes is usually stated gpm at 3600 rpm. Pumps are usually defined as cubic inches or cubic centimeter per revolution. Outside of the logspltter world with 3400/3600 rpm engines, most applications run either by 1800 rpm electric motors, or any imaginable range if driven from engines or gearboxes. Thus, size is given in cubic inches, easily converted to gallons with the rpm a given pump runs at.
-tank size: old rules of thumb were tank size in gallons = one to one and a half times pump flow gpm. This allowed 60 to 90 seconds of dwell time for oil in the tank to settle particles downward, and release air upwards. Not realistic or required anymore, especially for mobile equipment that just doesn’t have the space or weight for a big tank.
The old ‘rule’ was for industrial use, often with a fixed pump, where space wasn't a big deal. The sides of the tank provided enough area for cooling of simple circuits on presses, auto assembly stuff, conveyor lines, etc. New oils act differently and release air better. Better filters clean the oil. Basically no junk big enough to ‘settle out’ had better be in the oil or there are other problems. Heating and oxidation and additive life should not be a problem on a logsplitter or any consumer equipment.
Of more importance is tank design. As wk noted, the return oil can short circuit right across and go around again. So the internal baffling should decelerate the high speed flow from return line (way UNDER the fluid level, not above it), let it spread out and move slowly as a nice uniform lazy river with no dead corners, as long as possible to the suction ports. Some dead space at bottom is good for dirt and water to accumulate and be drained off. A large internal hex bushing type suction strainer works well as a return line diffuser-the flow goes out through all the openings or holes or screens.
Using that old rule, your tank should be 40 gallons. Not a chance.…… 10 would be I think too small, since that is effectively maybe 8 of oil and 2 of air. 15 gallons or so would give you about 30 seconds of dwell time with good baffle design and that is workable. I am working on a small machine design (sort of like a logsplitter) that will have about 11-14 gpm normal flow with a 3.5 gallon tank. I would not recommend that small for a home project. It is taking some creative return line diffusing and internal baffling, but weight is critical and for the life of a few hundred hours it will work just fine. If the tank is small, it is also cheaper to change oil out more often.
-tank: I would not use the old air tank. a. it is a bit small b. can't add baffles properly c. might be galvanized or coated and thus tough to weld leak free d. most importantly it will be full of rust and scale no matter what you do to clean it, especially if you can’t open it up for access.
So, now I just added another item to your list, to buy and fab a tank….. Most Northern or similar tanks are a simple box, with no baffles and no cleanout/access cover. Some are also pretty thin metal and with poor mounting feet that tend to crack easily.
-engine mount. I forgot, you did say vertical shaft. Not many bellhousings available as there isn’t a standard SAE mounting pattern for most L&G applications. You are sort of stuck making a plate, getting things aligned as best as possible then welded up, in lieu of doing the proper machining after welding. Do most of the welding except final alignment, then use lots of spacer blocks and clamps to hold things rigid. Weld the final joints with short beads and lots of cooling. This will minimize distortion. Not a big deal, the coupling might eat center inserts a bit quicker but it will work just fine for the hours use it will get.
-the 16 hp Kaw (V twin?) should be sweet. Son has a 19? Hp Kaw V twin on his Lesco commercial mower and it was a good engine, pretty smooth running. 1100 engine hours and it runs just fine.
-Prince valve: the 1/2 ports and 3/4 ports are based on the same casting and spool, so the pressure drop internally will be similar. Although it seems much bigger, the 3/4 version is not. However, the adaptors and hose fittings will be much bigger ID, so the 3/4 version is overall a better choice.
Mission creep, big time, but in the end you will understand the system well, know why you did what you did, and have a fast and powerful machine.
kcj
Since companies usually puff up the stats, I expected that 22 would be more in line with a valve claiming 25, not the other way around.
but....
