How to update the current (failing) noise risk management process to make it much more effective – and self-financing Noise Induced Hearing Loss claims of £400,000,000 per annum show that thousands of people are suffering hearing damage, most of which could be avoided by changing the way risk management is is carried out. A simple, innovative approach that dramatically improves the effectiveness of noise risk management was described at the BOHS
Reduce Product Noise and Vibration – the innovative and profitable way…
We have been extremely successful at applying engineering experience, intuition and technology transfer across a wide range of industries to eliminate product noise and vibration problems. Our clients have benefited both commercially and technically from this success.
Innovation, innovation, innovation… For experienced engineers, solving noise and vibration problems is as much an art as a science – we provide both to help with your product development. Our reputation for successful innovation is illustrated by the range of novel and elegant engineering solutions contained in our case studies.
Sample Past Project Arenas
air conditioning – axles – office products – pneumatic nozzles – trains – compressors – power presses – weighing machines – steering columns – vibratory filters – white goods – pneumatic tools – woodworking machines – fans – wrapping machines – vacuum cleaners – vacuum pumps – ships and yachts …
Product Noise Control Case Studies
Vax Vacuum Cleaner
During the re-design exercise for a new model, the noise from this vacuum cleaner was not only reduced by a factor of 10 (10dB(A)), but the subjective character of the noise was also substantially changed by eliminating tonal components to make it sound “nicer” (a specialist technical term in acoustics!). This also had the side effect of making the vacuum cleaner sound more powerful….vaxbeforafter
Quiet Compressor Development
As part of a continuous product development programme to maintain their world – leading reputation, CompAir asked us whether it would be feasible to re-design the noise control package on one of their compressors. The initial target was to remove the existing silencer element to reduce the overall size of the unit – without any increase in noise or a reduction in the performance of the cooling system. Source control modifications were developed for the cooling system which significantly reduced the overall noise from this element at source and also dramatically cut the tonal content (less “nuisance”). Coupled with modest flow and geometry changes, the new package reduced the overall “headline” noise from the compressor by 2 – 3dB(A), despite removing the standard silencer – and all without any cost or performance implications.compair before after
Engineering source control techniques have been developed for separators and filters that reduce the noise by 5-12dB(A) at very low cost and without compromising hygiene.
Cigarette Making Machine
An engineering noise control kit was developed for this Molins making machine. It reduced the noise by 4dB(A) at very low cost and without affecting normal access or operation. It was licensed by the manufacturer to provide a profitable retro-fit or overhaul option service. This illustrates the commercial opportunities inherent in the engineering noise & vibration control technology in which we specialise.
Cooling Down – HVAC
There is enormous competitive pressure on suppliers to develop quieter A/C and chiller plant. We’ve recently applied our engineering skills to reduce the noise from a new range of A/C units. As a result, they can now quote sound power levels that are at least 4dB(A) lower than before, at, quite literally, no additional cost to the units at all. This has provided the company with a significant commercial advantage and illustrates the benefits of introducing engineering noise control techniques during the development of new products. Quoting the project manager “.. is the unit actually running?! .. That’s an amazing result over such a short timescale”.
We were asked to look at improving the acoustic design of Custom Design speaker stands for up-market Hi-Fi aficionados. As a result of vibration testing on the stands, we recommended replacing the top and bottom plates with laminated “dead-metal” versions. These reduced the vibration response of the stands by up to 40dB (a factor of x100). According to the review in Hi-Fi Choice ” .. switch to the Acoustic Steel plates and the sound is even better, with a deeper, quicker base and a more open mid-band. There’s definitely a neutralising effect with the acoustic steel that zaps a lot of colouration, giving a far more neutral sound … Top value upgrade .. 5 stars.”
Pick-and-Place Suction Fan Noise Reduction – a packet quieter…
This suction fan used in a newly designed, automated pick-and-place system for food packets on a production line generated high levels of noise. Conventional fan silencing would not only have posed a hygiene problem (attenuators make use of porous acoustic absorbent materials), but would also have required acoustic enclosure. We re-designed the fan mounting system (interestingly, the fan itself was designed for model aircraft engines) and modified the geometry slightly. This reduced the fan noise at source by 8dB(A) without affecting the efficiency.
Eurostar HVAC Fan Noise Control – no space, no spare capacity, no problem…
The noise produced by the Eurostar Nightstock HVAC module (of which 140 had been built) was unacceptable both in terms of overall noise levels and tonal noise at the blade pass frequency of the fan and harmonics. Introducing conventional noise control techniques (silencers) to reduce the tonal content (by the manufacturer) had been unsuccessful. Maintaining the fan performance was critical and space within the air conditioning system was severely limited. Moreover, a retro-fit solution had to be developed very rapidly. An HVAC module was tested in the workshop for both noise and performance. The optimum solution involved a combination of Quiet Fan technology coupled with a new 7 bladed impeller design. These modifications could not only be retro fitted quickly and at low cost, but they also fitted entirely within the existing HVAC unit i.e. no space implications. The whole project was completed within just a few days.
As the fan noise reduction modifications reduced the noise at source, they simultaneously treated the intake, exhaust and break-out noise through the fan casing. Conventional techniques would not only have required separate silencers for each of these 3 transmission paths, but would also have had a substantial impact on the HVAC system performance. In addition, the source control modifications will last the lifetime of the unit without maintenance or cleaning and with no degradation in acoustic or aerodynamic performance. Despite the remarkably high acoustic performance with a 24dB reduction in tonal content and an overall noise reduction of 8dB(A), the flow was only reduced by a very acceptable 4.7%. This engineering approach is widely applicable to other HVAC plant where it can be used to reduce costs and improve system efficiency.