two stage hydraulic pump adjustment factory

I got the same pump as yours on my wood splitter, except mine is a John"s Barns but it is the same thing. Theses pumps give you 11 or 16 gpm under 700 psi and over 700 psi 6 to 8 gpm up to 3000 psi.

First, you must check your engine, if it will be able to handle this rise of pressure. Usually the factory setting for the first stage is 700 psi. If you got a 8 or 9 hp on a 11 gpm pumps, just forget it, the engine will dies on the effort. But if you got a 13 hp, it will works just fine.

Variable-displacement pumps are used in hydraulic systems where the flow requirements vary. This usually means the system has several actuators and, depending on the current cycle of the machine, the number of actuators moving at a given time will fluctuate. The most common type of variable-displacement pump is the pressure-compensating pump.

Pressure-compensating pumps are designed to deliver only the amount of flow required by the system to maximize efficiency and avoid heat generation. The compensator is adjusted to a pressure somewhat higher than that required to move the system’s heaviest load.

A pressure-compensating pump will deliver its maximum flow until the system pressure reaches the compensator setting. Once the compensator setting is reached, the pump will be de-stroked to deliver only the amount of flow that will maintain the compensator setting in the line.

Whenever more flow is demanded by the system (such as would occur when an additional actuator begins to move), the pump will increase its stroke to meet the new flow demand. Whenever the system flow needs to decrease (such as when one or more actuators are stopped), the pump stroke is reduced.

When the system is stopped completely, the pump stroke is reduced almost to zero. It will stroke only a very small amount or whatever is required to maintain the compensator setting in the line, overcoming any system bypassing or leaks. While a pressure-compensating pump is efficient, the standby pressure remains high.

Adjusting a pressure-compensating pump is quite simple. With all flow blocked and the system idle, the compensator valve is adjusted to the desired pressure. However, some pressure-compensating pumps have two valves mounted on the pump body.

The two adjustments can look nearly identical. This type of pressure-compensating pump is called a load-sensing pump. The second adjustment is called either a “load-sensing” valve or “flow-compensator” valve.

A load-sensing pump is designed to reduce its pressure to a much lower standby level whenever the system is idle. This can conserve energy and reduce heat and wear in systems that spend a significant amount of time in an idle condition.

The two separate pressure adjustments allow setting the compensator valve to the required maximum system pressure and the load-sensing adjustment to a much lower standby pressure.

Whenever the system is moving a load, the high-pressure adjustment limits the system pressure. For instance, as a cylinder is extended, pressure in the system will build as necessary to move the load. Eventually, the cylinder reaches the end of its stroke, and flow is blocked.

Most load-sensing systems have a pump-loading directional-control valve of some sort that can place the system in an idle condition until it is necessary to move another load. When the pump-loading valve is shifted, the system pressure drops to the much lower load-sensing valve setting.

A load-sensing valve usually is smaller than the compensator valve and typically mounted directly on top of the compensator. The compensator valve is closer to the pump. The load-sensing valve is factory preset and normally does not need to be adjusted during the initial pump setup. In most pumps, the factory preset is approximately 200-300 pounds per square inch (psi).

The most common reason to adjust a load-sensing valve is because someone unfamiliar with the pump has mistakenly attempted to set the maximum system pressure by adjusting the load-sensing valve instead of the compensator. This not only can result in unstable system pressure but in some cases can also void any warranty on the pump.

A typical configuration of a pressure-compensating pump is shown in Figure 1. A pump-loading valve is used to determine whether the system is idle or prepared to move a load. The pump-loading valve is de-energized whenever the system is idle.

Pilot pressure on the left-hand side of the load-sensing valve is then released to the tank. The pilot line on the right-hand side of the load-sensing valve is connected to the pressure line at the pump outlet. System pressure shifts the load-sensing valve and directs pressure to reduce the pump stroke so that system pressure drops to the load-sensing setting of 300 psi, as illustrated in Figure 2.

When a load is to be moved, the pump-loading valve is energized. This directs pilot pressure to the left side of the load-sensing valve, keeping it from shifting. System pressure shifts the compensator valve to de-stroke the pump exactly the amount necessary to limit system pressure to the compensator setting, 3,000 psi as shown in Figure 3.

To make the pressure settings, always adjust the load-sensing valve first. The pump should be deadheaded by closing the manual hand valve. With the pump-loading valve de-energized, pressure will build only to the current setting of the load-sensing valve. Adjust the load-sensing valve to the desired pressure.

Once the load-sensing valve is set, energize the pump-loading valve. System pressure will then build to the current compensator setting. Adjust the compensator to the desired setting. Open the manual valve, and the system can be placed back into service.

Jack Weeks is a hydraulic instructor and consultant for GPM Hydraulic Consulting. Since 1997 he has trained thousands of electricians and mechanics in hydraulic troubleshooting methods. Jack has...

http://www.energymfg.com/pdf/16445x.pdfGood catch, I should have seen that. Now the interesting part is that the relief is preset 2000psi from factory and a max range of 2500psi. His engine should pull that without any serious bogging. Rereading the first post, he says it boggs out and stalls. I am now wondering if its the engine that is stalling, ( which is what I thought he was saying),or the cylinder that is stalling. I think that issue needs to be clarified before going any further. If the cylinder is what is stalling, and the engine continues to run, it could just be a matter of the relief being set to low, or to small a cylinder for the wood being split. If it is indeed not shifting into lowflow/high pressure, then he might need to adjust the pump to the the 650psi high flow/ low pressure. Remove the cap on the inlet side of the pump. Under the cap is a slotted screw. Turn clockwise to increase pressure. Turn the screw all the way clockwise to the stop and see if the engine can handle it. If not then back it out a little and try again. Run the engine full throttle and plan to play with the setting until you find the limit for your engine. You will find that the higher you can run the pressure on high flow side, the less the pump will kick down into low flow/high pressure and the faster your splitter will work. If you engine is actually already what is bogging, you may have to turn the screw counter clockwise to lower the unloader pressure.. It is best to use a pressure gauge, but you can do this by ear. If its killing the engine, just turn the screw out until it no longer kills the engine. You should adjust the relief setting on the control valvle first before trying to adjust the unloader valve on the pump. The load is what will cause the pressure to build, you can simulate a full load by fully extending or retracting the cyl, and the relief valve on the valve will activate. If it will not get to 2500 psi, then the valve pressure relief (on control valve) is not set, or you don"t have a load equivalent to 2500 psi. With a gauge installed, pressure will be at a minimum until you activate the lever on the control valve, Once lever is activated, pressure should climb on the gauge until the cyl is fully extended or retracted, at which point the pressure will climb rapidly to the relief setting. Watch the gauge, it should jump from the settings on the pump unloader valve (650psi), to the setting on the relief (2500psi). You may need to split a round or two to actually see the pressure spike as the spike can be pretty fast

I will just add, that I have never had to adjust the relief on the control valve or unloader relief on a pump that was new out of the box. Usually if the reliefs need adjusting, its because someone has already been messing with them. Usually the factory guys have it pretty close, not saying mess ups dont happen, just that it is unusual when it does. I also usually use large bore cyls and bigger hp engines than the minimums required. If you have the hp to pull the pumps and cyls that create more than enough force, the factory relief setting will usually take care of themselfs.

2-stage hydraulic pumps are used in motor-driven operations wherein a low-pressure, high rate inlet must be transferred to high pressure, low flow-rate outlet. Single-stage pumps are rated to a static max pressure level and have a limited recycle rate.

To achieve high pressure without a 2-stage unit, the drive engine would require significantly higher horsepower and torque capacity but still lack an effective cycle rate. Other hydraulic pump variants exist – such as piston pumps – but are expensive, making 2-stage units more feasible.

For example, a single gear hydraulic pump might be designed to generate a high-pressure output. Still, it will be unable to repeat a cycle rapidly due to a necessarily low flow rate at the intake. A 2-stage unit ensures consistent flow to increase cycle turnover.

Compactors utilize a similar 2-stage process. High-pressure flow drives the compacting rod, while the low-pressure flow retracts the mechanism and feeds the high-pressure chamber for repeated impacts.

2. Once the first-stage pressure meets a certain pressure threshold, a combiner check valve will open and feed into the second-stage, small-gear unit – joining flows at relatively low pressure.

A piston pump operates according to variable displacement. Flow is determined by the angle of an internal slant disk attached to the pump shaft. Pump adjustments – like torque or horsepower limiters – allow piston pumps to emit a max flow rate regardless of pressure level.

In most cases, hydraulic piston pumps are an order of magnitude more expensive than gear-based pumps. Potential downtime and part replacement in high volume work conditions exacerbate price disparities further.

Chiefly: fuel and power consumption. A piston pump operating in high-pressure ranges will regularly demand the full horsepower capabilities of its associated drive engine – increasing the power utilization of the system.

Opportunity cost may also be considered when using a piston pump. Depending on the application (e.g., log splitting), work output can be heavily impacted by the cycle speed of the pump. Not only is a piston pump more expensive to peruse, it is also slower than 2-stage pumps.

Panagon Systems has specialized in manufacturing industry-standard and custom hydraulic assemblies for 25 years. Reach out to our team for a consultation on your specific operational and equipment needs.

How does a 2 stage hydraulic pump work? Knowing the answer to this question means going back to the basics. This includes understanding that 2 stage pumps are usually called log splitter pumps. In terms of purpose, these pumps are an amazing way to expect better performance without worrying about an increase in the horsepower.

A 2 stage pump is often regarded as an excellent time-saver. This is because the pump is composed of two pumping parts, along with an inside pressure-sensing valve which works by cutting between the two. A section of the hydraulic pump creates the max gpm flow rate at a relatively low-pressure rate.

As mentioned, looking inside the housing of this type of pump will introduce you to two components – a huge volume pump, alongside its low volume counterpart.

What makes this pump unique is that it makes possible that a hydraulic system produces either high pressure or high flow, which can easily be powered using an engine of a moderate size. The usual log splitters come between 5 and 12 hp.

In contrast to single stage pump which is composed of a single dual suction impeller that is situated on both vehicle sides and giving volume to all of the vehicle discharges, the2-stage hydraulic pump features two suction impellers that work side-by-side.

With this in mind, it is the operator’s call whether more volume or more pressure is required. This can be done by choosing the right switch that is located on the panel of the pump.

In a standard log splitter, a log is placed by the operator on the splitter, shifting a directional valve so as to route fluid coming from the pump and into the cap end of the cylinder. Then, the smaller pump works by moving the piston rod at a low speed, and can still attain higher pressure in pushing the wedge to the log, splitting it.

Engine– The engine is typically a small 4-stroke gasoline engine. It works by providing power to the entire system. It is connected to the hydraulic oil pump. A regular log splitter has a 5-hp gasoline engine or a a higher horsepower such as a Briggs & Stratton engine.

Hydraulic Oil Pump – This component produces a continuous high-pressure oil stream, running to a valve. The usual splitter features a 2 stage hydraulic oil pump that is rated at a max of 11 gpm, at 2500 psi.

Valve – This part allows the operator to actuate the hydraulic cylinder, thus splitting a log. The valves work by applying forward and backward pressure into the piston. A certain type of valve is called “spool valve” because it looks similar to a spool of thread.

Tank – The tank is the component that holds the hydraulic oil which feeds the pump. There is also a filter that keeps the oil clean. It can also be found in the tank. A usual log splitter comes with a 3.5 gallon hydraulic oil tank.

It is also possible to speed up the log splitter. For this, you need to have a bigger hydraulic pump. As you also upgrade your pump, you may also have to upgrade the size of the tank. This will help in preventing fluid overheating. You may also want to increase the size of the hoses, as this will also help in accommodating the increase in the flow rate.

As such, controlling the flow rate of a pump requires setting the output pressure towards the point using the P-V diagram, allowing the pump to provide the flow rate desired.

2 stage hydraulic pumps are often seen in hydraulic systems. They work by allowing the passage of different substances right into the pump, as well as the other components that are in the system. The different aspects of working can be adjusted, such as the valve accuracy, pressure settings, and creating minor adjustments using tools that you can find at home.

Locate the adjustment screw that is situated at the back of the hydraulic gauge. For this process, you can use a flathead screwdriver in turning the screw. This step enables you to easily adjust the needle of the screw. When needed, you can also turn it into zero.

This time, take time in adjusting the pressure switch. This switch can be found at the back of the hydraulic gauge. The best tool for this step is a wrench, using it to loosen the nut on the switch. Turn the adjusting screw afterwards. The pressure switch may also be adjusted in stopping the pump as it reaches a given setting in the pressure. Turn it in a counterclockwise direction to decrease the setting for the pressure switch.

After adjusting the 2 stage hydraulic pump, you can then focus your attention on adjusting the pressure regulating valve. This valve is situated right beside the pressure switch. This can be done with a wrench, loosening the nut on the switch.

How does a 2 stage hydraulic pump work? As mentioned earlier, this equipment is truly a life saver and very effective. It contains two sections for pumping, along with an internal pressure-sensing valve, cutting over between both. A section creates the maximum gallon per minute flow rate at a low pressure. Among the uses include drawing the piston back from a log after splitting the log. Drawing it back to the cylinder requires little force, and should be done fast, so as to expect the best possible flow rate at a lower pressure.