The NRS reduces total noise emission by up to 10 dB and can be fitted without dismantling the hydraulic unit.
The NRS system is made of 3D High Distance polyester fabric, which is tear-resistant, resistant against all commercially available hydraulic fluids and temperature-resistant from –40 to +120°C.
The pulsation of hydraulic pumps generates very strong vibrations that are not damped sufficiently by the aluminium bell housings normally used today. Moreover, rigid bell housings do not provide any isolation of structure-borne sound between the electric motor and the hydraulic pump. Vibration tests at Raja-Lovejoy have shown that the emitted air and structure-borne noise is at exactly those frequencies to which the human hearing is most sensitive. In some unfavourable cases the thin-walled aluminium bell housing even amplifies the pump’s running noise, acting as a resonance chamber that can further increase the oscillation amplitudes.
The NRS system was developed in cooperation with the Technical University of Chemnitz, the Cetex institute for textile and processing machines, and testing and certification company SLG. In tests the newly developed NRS system reduced noise levels by 50%. NRS is available in four different system widths and three lengths, both as retrofitting kit and for original equipment.