Mankato Bruce, the electrician?
I would use a two spool valve if you don't need detent return on the splitter part. You still have to control the flow and speed to the lifter or it could catapult logs right over you into the trailer.....
Cut & paste & edited from answering this in another forum. There are also other ways to achieve that I deleted:
2 parts to post
kcj
HOW PROVIDE AUX HYDR FOR LOG LIFTER
Several ways to do it, depending if adding to an existing circuit or building from scratch.
Personally, I’d either:
A. Find a two spool single valve (if I didn’t need detented return) and shim the spool to limit the speed of operation of the lifter, or
B. Use a 6 port selector valve for lifter or splitter, or
C. Add a second power beyond valve for the lifter (if I wanted detented return), before the existing splitter valve, and locate it somewhere away from the main valve so there is no way of confusing the levers.
Three issues come to mind:
A. The selecting circuit to get oil to the second cylinder. That is easy.
B. Controlling flow. If you send all 11 or 16 or 22 gpm to a small lifter cylinder, it could toss the logs over the beam right into the trailer….
C. Heat and throttling losses involved in taking a couple gpm off the main circuit. Any way this happens the rest of the flow is converted to heat. Since this is an intermittent cylinder use, don’t worry about it. If a continuous use, like the conveyor motor discussed earlier, heat would be a big issue and the circuit needs to be more complicated to prevent overheating.
A. SELECTING WHICH FUNCTION
-2 SPOOL VALVE. This would be the cleanest installation.
The handles should be oriented differently (say one 4 inches shorter, or turned down instead of up) so there is no chance of accidentally pulling the wrong handle full stroke, moving the lifter, and having a log roll at you.
Getting a two spool valve will be harder to find and more expensive than the common box store splitter valves. Buying new is easy to build up just what you want, but scrap or surplus will be harder. The cylinder spool section is normal and common. The detent section is a bit harder to find in industrial applications, especially with a kickout. Most surplus/salvage detented manual valves are for motor use. They will have all ports open in center, (cylinder won’t hold position) and a detent in each direction but no kickout. They are made for running a motor continuously. Depending on the valve, you can buy various spools to convert. Most mobile valves are loose enough in tolerance that new spools interchange in the old body. You can buy detent and kickout kits. Overall though, you will probably spend more buying parts then buying a valve new.
If you don’t need a detented return (i.e. if the return cycle is fast enough, say 3 or 4 seconds, the detent isn’t necessary) then a simple two section cylinder spool valve with inlet relief valve is easy to find surplus or salvage. This is by far the cleanest if you don’t need detent.
-6 PORT SELECTOR valve between the existing valve and the existing cylinder.
Basically this takes the two A & B lines out of the valve and sends them to one of two possible directions: to the existing splitter cylinder, or to the log lifter cylinder. Cross SD4 and Prince DS. I didn’t see a 6 port in Energy Mfg. (I only list these three because they are the cheap end of the industry and most common in the retail channels.)
Valve needs to be big enough to handle not only the pump flow, but also the return flow when cylinder is retracting. 11 gpm from pump could be 15-18 returning from closed side of cylinder in retract. Minimize the pressure drop, as every cycle of splitting must go through this valve.
+Can add to existing machine pretty easy.
+When in splitter mode, the lifter is disabled. It cannot accidentally move if the main valve were hit by hand or by a piece of wood. If there is a second spool for lifter, the lifter is live all the time.
-Cost of the 6 port valve is close to adding a spool to the main valve if building from scratch.
-Extra hoses and space required.
-? Extra motions: move selector, then move manual valve, then selector back to split. May have to switch back and forth a couple times to align log on the beam and bite it with the wedge. If the lifter is not used a lot, this could be a minor issue.
-3 PORT SELECTOR in the P line between the pump and the original splitter valve. This sends the oil to either the lifter or the splitter.
+Can add to existing.
+Lifter is disabled in splitter mode.
-Needs another relief valve on the pump side, as the selector blocks flow as it passes through from one direction to the other. This blocked condition, even briefly, could spike the pressure and blow hose or pump.
-Still need the separate lever valve for the lifter. Costs increase.
-? Extra motions: move selector, then move manual valve, then selector back to split. May have to switch back and forth a couple times to align log on the beam and bite it with the wedge. Given that lifter is not used a lot, this could be a minor issue.
-More complexity and cost. I would not go this way.
-MANUAL STEEL HIGH PRESSURE BALL VALVES, two required, in the P line. Turn on the line to the lifter, then turn off the splitter. Lift the log, then splitter on, and lifter off.
+Only advantage I can see is that parts are easy to get.
- -Needs additional RV, chance of getting valves turned in wrong order, and lot of messing around. I would not go there. Only listed because it was asked.
-SECOND VALVE, ADDED BEFORE MAIN SPLITTER VALVE
The new lifter valve needs to be either power beyond or series function. It also needs a relief valve built in if there is not one at the pump, since the RV in the existing splitter valve is downstream of this point. The existing splitter valve can be used with no changes.
Power Beyond valves have one inlet and two outlets. One is a normal tank line for return from a function operated by this valve. It also connects to spring and seal cavities so that high pressure is never applied to those places. The second outlet goes downstream to other valves. If nothing is being operated in valve 1, the full flow is available to operate downstream functions in valve 2. If anything is operated in valve 1, usually there is no flow downstream to operate valve 2.
Add sketch and schem
Series valve has only one outlet port, but that port as well as spring and operator cavities can withstand full pressure. If a downstream valve is operated, the entire Series valve sees full system pressure. If functions are operated in both valves, the sum of the pressures required by each function can’t exceed the pump RV setting. If two cylinders each required 2000 psi to operate, but were connected to series control valves, either one would work fine individually. However, if both were operated at once, the resulting demand of 4000 psi exceeds the relief valve setting and neither cylinder would move.
If loads in each valve are quite low, a series valve allows both functions to work at once. If loads are high, both will stop.
Add sketch and schem
+Easy to add.
+Single spool power beyond valve is easy to find. Does not need detent.
+Keep existing splitter valve
-An extra valve
+ and - Lifter is live all the time.
-SECOND VALVE, ADDED AFTER THE MAIN SPLITTER VALVE
If the lifter valve were added downstream of the splitter valve (in what was the line to tank), the lifter valve does not need to be PB or series, BUT the existing splitter valve must be changed to PB or series. Most cheap valves, especially with detent and kickout option, should not have full system pressure applied to the tank port. I don’t know of a readily available, cheap Power Beyond valve with detent and kickout.
+Easy to add.
-Single spool power beyond valve with detent is harder to find.
-Have to buy two new valves
-An extra valve
-Change the hose because line between the two valves will now have full pressure at times.
+ and - Lifter is live all the time.
I would not go this way unless the valves were available free.
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