The energy-efficient force of new economy
Cover story . Hydraulic drives: energy-efficient application
The energy-efficient force of new economy.
A proven technology should never be written off. Unimaginable strengths often slumber here, which should be developed further. At transfluid®, we are always looking for better options, which means we always practically implement new ideas. In this way, the hydraulic pumps in our new tube processing machines are controlled more and more frequently using servo motors. This provides a wide range of advantages that improve the processes, ecological sustainability, and commercial effectiveness enormously.
First of all, this would mean the level of high efficiency, which is impressive because of energy savings up to 70 % versus conventional hydraulic systems. This is made possible thanks to the effective interplay of diverse technical details:
Electronic pressure controls
The speed and therefore the volume flow of the pumps is adjusted precisely to the required pressure. Energy losses that are otherwise familiar due to oil flowing down to pressure valves are absent.
Electronic volume flow controls
The speed and therefore the volume flow of the pumps is adjusted precisely to the required volume flows. Conventional flow losses due to flow valves are avoided completely.
Immediate motor stoppage
As soon as hydraulic functions are no longer active, the motor stops. At this moment, no heat will be produced in the system. Even during the automatic cycle, this is reached multiple times. For example, if a bending machine's electro-mechanical axes, length feed, or rotation functions are active, then the servo pump will stop. This reduces the overall activation duration of the pump - This saves energy.
Comparably small motors
In fact that the servo motors are able to be briefly overloaded multiple times the rated power, construction size is clearly reduced compared to normal alternating current motors. This results to lower mass inertia of the motor and improved dynamics.
Use of smaller hydraulic pumps
In fact that the servo motor has got an increased speed range, comparably small pumps may be installed, which may be run at up to 3,000 RPM. The mass inertia of the pump is therefore low.
Completely free of cooling
Normally this high energy efficiency does not require cooling. This saves on the energy consumption of cooling. Furthermore, no dust is agitated by a fan wheel. No noise is produced by a ventilator and cleaning of cooling fins is also unnecessary. Low noise emissions We use quiet internal toothed wheel pumps for this purpose. Flow noise due to throttle and pressure valves is prevented. Absolute quiet is possible in stand-by mode, because the pump is stopped and there is no cooling noise.
Clearly reduced operating costs
Power is saved thanks to significantly increased energy efficiency.
Example: Our hydraulic bending machine DB 2076 3A-CNC
A conventional hydraulic aggregate featuring a flow performance of approx. 60 l/min and an operating pressure of max. 200 bar normally requires a 15 kW drive. 80% of the drive power is certainly required on average, since normal motors also require high levels of power even while operating in idle mode. At a daily operative duration of six hours, this results in an annual power consumption of 15,840 kWh.
Normally a servo pump has got an average power consumption below 4 kW at a typical bending cycle including break times of 5 s for removing and loading tubes, which corresponds with an annual consumption of 5,280 kWh. If a kilowatt hour is calculated at 0.25 euros, then this technology already saves on annual power costs of 2,640 euros for this application.
In addition to this, maintenance and repair costs are also reduced thanks to the simplified valve technology. Throttle and pressure valves can normally be omitted completely. Pressure switches for querying axes are also omitted and replaced centrally by a pressure sensor.
A touch panel regulates the pressure of all axes, and the speed of all hydraulic axes may be set comfortably.
The path positioning of the axes is possible up to an exactness of 0.05 mm, provided the integration of a position measuring system is requested. Activation via an expensive control valve including control electronics may even be partially omitted. The "HNC axis" therefore becomes cheaper. Compared to conventional hydraulics, the price of the servo pump is nearly identical. The sustainable efficiency pays for itself right from the first practical application.