The new external Silence Plus gear pump from automation equipment manufacturer Bosch Rexroth reduces noise emissions by an average of 15 dBA, compared with conventional external gear pumps, the company states.
When used in coolant, filter and lubricant cycles at pressures under 50 bar, the pump runs almost silently.
For many applications, this eliminates the need for secondary noise reduction measures.
In addition, Bosch Rexroth, which is locally represented by hydraulic components manufacturer Hytec, has also moved the measurably reduced noise into a lower, more tolerable frequency range.
Field tests have shown that, at lower pressure ranges, the increased electric motor noise caused by the pump is barely noticeable.
At a working pressure of 10 bar, airborne noise increases by only 3 dBA, from 52 dBA to 55 dBA. In addition, by moving the noise into a 35% lower frequency range, its pitch is close to that of the electric motor. The result is a low-pitched ambient working noise that is much more pleasant than with other external gear pumps.
The design prevents oil from getting trapped between the tooth flanks and reduces pressure pulsation in the system by up to 75%. This reduces body-borne noise throughout the entire hydraulic cycle.
The new pump complements Bosch Rexroth’s existing pumps range. Having identical mounting dimensions, it is fully compatible with other pump models in the standard, as well as the Silence series, which enables users to exchange pumps without having to make any design changes.
The high-precision external gear pump ensures full surface, zero clearance and dual-flank contact in all areas of the gears. The pump’s helical gearing with a non- involute tooth profile creates a closed line of contact in the form of the ‘figure eight’. The first variant includes nominal sizes with a performance range of between 12 cm³ and 28 cm³ in every revolution.
The quiet hydraulic pump is especially suited for use in tool and paper cutting machines, passenger elevators, car lifts and materials handling or waste presses in residential areas.
Depending on the application, the Silence Plus pumps also complement the range of pumps used in Bosch Rexroth’s variable-speed pump drives, which reduce the energy consumption of hydraulic power units by up to 80%.
The Silence Plus was declared the overall winner of Industriepreis 2011 out of a field of more than 500 applications. This industrial award was bestowed at one of the world’s foremost technology events, the Hannover Messe, in Germany.
The pump was also awarded a ‘Noise Oscar’ by the Noise Abatement Society at the eleventh John Connell Awards, presented in the UK in November last year. These awards honour innovations aimed at making a positive contribution to the reduction of excessive noise exposure in industry.