HYDRAULIC PLANT PHILOSOPHY

The traditional machines have always been characterized by an engineering foreseeing big tanks under pressure, the so called accumulators. Such systems are subject to periodical revisions and controls from the part of the Bodies appointed by the Public Administration Authority. As a matter of fact as time passes by and also as a consequence of the corrosive action of the fluid, their trend is to deteriorate and therefore to get even dangerous. The checks foreseen are meant to control their compliance and endurance and eventually, if they proved to be not complying with their strict technical specifications, they are derated. When un accumulator get derated that means that its use in the circuit of the press has been accepted but it must work then absolutely under a lower pressure, which is established time by time by the Body in charge during its inspection. This entails that a lower force will be available to the press, thence by derating the accumulators, automatically also the press get derated. The components forged which before the periodical control of the accumulators proved to be perfect may then prove to get refused or even no more forgeable since the press has become too small. It is necessary to underline that such control activity can lead to some Machine-stop even of 3÷4 weeks. A system realized in such a way, foresees the use of a series of pumps having a fixed flow rate and which do pump continuously the fluid into the accumulators under the max pressure. In this way the energy wasting is maximum since the fluid which had been pumped under the maximum pressure is used also when only low forging forces are needed, and therefore by the maximum energy wasting.

In order to face this troublesome matter characterizing the 'old conception' machines the new TDS series definitely eliminated the use of the accumulators and of any tank under pressure. In this way the TDS series drastically reduces the Plant-stop and increases the average rate of machine availability to be working and always at its max nominal pressure.

It was possible to get these evident technical advantage by the use of a single tank small sized, under no pressure but always outdoors, equipped with its corresponding dust-proof protection devices. Even some pumps equipped with pistons, no valves, and having a variable flow rate are used. Such pumps are driven by electric three phase motors which are coupled directly to the pumps. The pumps are kept at zero flow rate at every pause or when the machine is not working and the corresponding motors are set at the minimum rotation (it is even possible to stop them by a suitable drive) and in this way the maximum energy yield is assured. In the forging phases the machine will be working in its maximum energy yield conditions since the pumps' flow rate percentage and the motors' rotation speed are adjusted.

The electrical Power yield is about 95% , its net cosφ being equal to 0,89÷0,90.

The benefits deriving from that are noted immediately during the production of the forged components: high speed forging is available, in an absolutely controlled manner, and a continuous thermic addition to the piece being forged is available so that the thermic losses of the material being worked are fed and therefore the forging time, before re-starting the heating in the oven is remarkably lengthened. In many instances the components which had to be set into the oven once again in order to end the forging, can now be obtained by a single heating. For this reason the machine has been equipped with remarkable installed electric power. Such power has been fractioned, therefore is possible to work even by two, three pumps at the same time and therefore once again some energy will be saved, thence the incidence of the electric energy on the piece will be always the smallest possible.