Hydraulics specialist R+L Hydraulics GmbH has introduced a system for reducing hydraulic equipment noise emissions. Consisting of a textile shrouding for hydraulic unit bell housings, the patented NRS system is claimed to be able to reduce the total acoustic power output by up to 50 per cent, i.e. the equivalent of about 10 dB. The NRS system can be fitted without dismantling the hydraulic unit and is a cost-effective solution as original equipment and for retrofitting to existing hydraulic equipment. Vibration issue The pulsation of hydraulic pumps generates strong vibrations that are not damped sufficiently by the aluminium bell housings commonly used today. Moreover, rigid bell housings do not provide acoustic insulation against structure-borne sound between the electric motor and the hydraulic pump. In unfavourable circumstances the thin-walled aluminium bell housing even acts as a resonance chamber that further increases the oscillation amplitude and thereby amplifies the pump's running noise. Joint project R+L Hydraulics was involved in a joint project aimed at developing a solution to this problem. The brief was to develop a practical, cost-effective system that could also be retrofitted to existing equipment with poor sound and vibration insulation. In tests, the NRS system – which has now been patented – reduced noise levels by 50 per cent or the equivalent of up to 10 dB. The housing of the NRS system consists of a recyclable 3D 'high distance' polyester fabric that is said to be tear resistant and also resistant against all commercially available hydraulic fluids. It is also claimed to be temperature resistant from -40degC to +120degC. The NRS system can be supplied in four different widths and three lengths both as original equipment and as a retrofitting kit. Other solutions In addition to the NRS system, R+L Hydraulics produces and distributes a comprehensive range of hydraulics accessories, such as heat exchangers, oil-air coolers, offline cooling units, rigid and damped bell housings, aluminium and steel tanks, power transmission couplings and sintered metal products. www.rl-hydraulics.com www.jbj.co.uk