Hydraulic energy is widely used in our daily life. Actually log splitter machine is a great example to understand basic hydraulic circuit and components. We would like to give brief information regarding special directional control valves and gear pumps for log splitters. High flow-low pressure and high pressure-low flow working modes are generally used in log splitters, hydraulic press and garbage trucks.
Basic hydraulic circuit for log splitter
In a typical log splitter; user operates a control valve to route fluid from the pump to the cap end of the cylinder. The combined flow from tandem pump extends the cylinder’s piston rapidly to reduce the time it takes to advance the wedge to the engage the log.
- Once the wedge engages the log, the log resists further extension of the cylinder, pressure increases.
Big section of tandem pump (also called high-low pump, it helps to use smaller power in the system) does not provide flow to the system directly, only small pump provides flow. When the pressure reaches a certain value, unloading valve opens and big pump flow is unloaded.
Directional control valve for log splitter
- Directional control valve directs the fluid to the hydraulic cylinder. There is a pressure relief valve in valve body to protect the system. When the pressure reached a set value, valve lever is back to neutral position.
- In some models there is a function of extremely fast “rapid extend” high speed mode. It has been designed to reduce system cost by allowing a single stage pump to be used in systems currently using two stage (hi-low) pumps. When extra force is required it allows the user to manually shift from high speed mode to high force mode.
High-low tandem pump
- Another component which is widely used in log splitters is high-low tandem pump. During rapid traverse, both pumps supply flow to system. When pressure rises during clamping or feed, the large-volume main pump unloads and the small pump maintains pressure. These gear pumps offer the advantage of requiring lower power of the motor.
There are gasoline engines or cast iron gear pumps for different log splitter designs. Capacities of the machines also vary from 5-6 ton up to 25-30 ton.
Photos in the post are used for information purpose only.
Sources
https://www.hydraulicspneumatics.com/applications/forestry-lumber/article/21883550/log-splitter-works-doubletime