Efficient Construction Machine Cooling: How Variable Displacement Pumps in Fan Motors can Finally be Cost-Effective This solution only generates the energy that is actually needed
Energy prices are on the increase – and this has a direct impact on large construction machine cooling. If you work with hydraulic fan motors, this mostly involves the use of inefficient fixed displacement pumps. They are inefficient because they produce more energy than is needed. They constantly provide the maximum flow rate, although this is needed in very few load cases. The alternative is variable displacement pumps with electronic load-sensing, but these pumps are costly and the valves needed for the pump control are excessively complex and expensive. But not any more – HYDAC has an innovation that makes variable displacement pumps more cost-effective: the PPDB08PZ-01 combination valve.
What Pump should I Use to Cool my Fan Motors?
Fixed displacement pumps are inefficient.
For thermal management in construction machines, hydraulic fan motors are installed that can provide precisely the cooling capacity that is needed via a variable rotational speed. A fixed displacement pump combined with a proportional bypass controller is the wrong choice here. This combination is a real energy guzzler, as it diverts the flow that is not needed for the fan motor through a bypass valve, resulting in high throttle losses. But the low costs speak for themselves, as pressure-controlled pumps and their complex pump control are too costly. It's no wonder that people tolerate the inefficiency of the fixed displacement pump.
The Innovation that makes Variable Displacement Pumps in Fan Motors a SuccessCost-effective at last: variable displacement pumps with the HYDAC combination valve
The advantages of pressure-controlled pumps are plain to see: lower energy consumption, power supplied as needed, greater efficiency – and reduced diesel engine exhaust emissions, as the media being cooled can function at an optimal operating temperature. All of these are important factors which make using your construction machines more sustainable and energy-efficient. This was previously only possible with load-sensing controls and external pilot valves, but HYDAC now has a valve that can do it all.
Our latest development: to operate your variable displacement pump with electronic load-sensing, you now only need one valve. Our electroproportional swivel angle control valve is compact, inexpensive and highly efficient. That's why it makes sense to rethink the variable displacement pump – with the lower valve costs and reduced energy consumption, you will find that pressure-controlled pumps quickly pay for themselves. With energy prices constantly increasing, this means you can be well prepared for the future.
How the HYDAC PPDB08PZ-01 Combination Valve WorksThings are going to get a little technical now
- Closed-loop control of the pump pressure: The combination valve measures the pump outlet pressure and uses direct control of the pump swivel angle to achieve closed-loop proportional control of the pump pressure.
- Setting the pump pressure mechanically: The valve has an inverse performance curve. This means that at zero solenoid current, the pump pressure is at its maximum value. You can set this value at the valve mechanically.
- Pressure measurement & setting flow rates: A cartridge valve replaces the load-sensing control and the external remote valve. It measures the pressure at the pump connection and directly alters the pressurisation of the swivel angle actuator to set the required flow rate.