Industrial Noise & Vibration Centre

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Case Studies

An elegant engineering solution to your noise or vibration problem may already be available. Search below the largest database of source control case studies in the world for alternatives to conventional, high-cost palliatives such as acoustic enclosures, silencers, barriers etc.

Showing 16 to 30 out of 92
  • stack noise
  • environmental noise
  • fan noise attenuation
  • fans

Stacks of Low Cost Noise Control – emergency stack noise reduction

cement works fan and stack noise attenuation

Unfortunately, the plant update to improve the efficiency of the exhaust fans in a large cement works created a serious noise problem that generated complaints from miles around. A novel, low cost attenuation system was designed and fitted over a weekend to avoid the eye-watering down-time cost required to implement conventional solutions.

Conventional stack silencing would have resulted in an unacceptable delay in solving the problem plus massive capital and prolonged shut-down costs. Our alternative solution was based on the design of a set of bespoke stack silencer elements tuned to suit the noise signature. These were pre-fabricated off site and then inserted into the stack through a small access door over a weekend. The result was a 19dB noise reduction over the critical frequency range with no effect on the fan and stack efficiency – and at a small fraction of the cost of conventional silencing.

  • environmental noise
  • fan noise attenuation
  • fans

Steelworks Industrial Fan Noise Reduction – £1,000,000 cost savings

Tata steel gas fan stack noise attenuation

3 off, very large, 4 megawatt steelworks fans had been the cause of environmental noise issues for years. The problem was solved within months at a tiny fraction of the cost of attenuators by implementing our aerodynamic fan noise reduction technology. Fan power consumption was also reduced, making this a self-financing project.

A second opinion saves a £million…

The fans generated a low-frequency hum (c162Hz) over a wide area. As the fan speeds varied, sophisticated resonator silencers were ruled-out and conventional attenuators would have imposed a heavy penalty in terms of cost and reduced fan efficiency. Tata approached us for a second opinion as to potential alternatives. Our solution was to develop novel fan casing modifications, avoiding the need to modify either the existing ductwork or the stacks to fit silencers - thereby minimising downtime. These modifications have eliminated the noise at source for the lifetime of the fans. Significantly, the new fan modifications require no maintenance and do not affect the efficiency of the fan. Moreover, the willingness of Tata to invest in new and innovative technology has reaped very substantial rewards compared with conventional silencing:-

  • 94% reduction in noise (12dB)
  • capital cost savings of over £800,000
  • substantial environmental benefits (carbon emissions)
  • c £200,000 saved each year on running costs (power and carbon)
  • scrap extract
  • fans
  • attenuators
  • silencers
  • fan noise attenuation

Scrap Fan Noise Reduction – occupational and environmental in one

Scrap extract fan noise reduction

Attenuators do not take kindly to the passage of scrap – which is a problem when installing noisy chopper fans. Our cutting edge aerodynamic modifications, however, are even robust enough to be able to cope with extreme scrap metal. In this example, both occupational and environmental noise problems were simultaneously solved at source. Three sets of chopper fans are used to pull-off scrap cans from the lines and to shred them for recycling. These generated high levels of tonal noise, causing both occupational and environmental noise problems. Instead of fitting conventional fan attenuators, acoustic enclosures and noise lagging at a potential cost of £30k or more, our Quiet Fan technology was fitted to the fans in a matter of hours to give an overall noise reduction of 22dB(A) at an installed cost of c £1000/line – a capital cost saving of 90% and with no effect on fan performance or efficiency.

Unlike fan silencers, the modifications are unaffected by the passage of scrap cans and will last the lifetime of the fans without maintenance – and at less than 1% of the previous noise level…

  • hygiene
  • noise control
  • buy quiet

Supermarket Food Tray Washing Line Noise Control

Tray wash noise control

Two newly installed automated lines had failed to meet the Christian Salvesen noise specification despite the efforts of the supplier. Our engineering audit predicted both the cost and the precise noise levels that could be achieved using best practice control techniques. Following implementation by the manufacturer, noise levels were reduced from typical levels of 85 – 91dB(A) down to the 82dB(A) target and with more efficient drying performance.

The manufacturer has adopted the more effective, lower cost and more practical INVC technology as standard practice, improving performance and margins.

  • hygiene
  • noise control

Die-Header / Tablet Machine Noise Reduction

Die header and tablet machine noise reduction

The noise from die header machines and tableting machines (tablet presses) used to manufacture hard sweets, tablets and other products in the food and pharmaceutical industries is often 95 – 101dB(A). The conventional approach is to fit them with high-cost acoustic enclosures that cause serious access problems and also makes cleaning difficult. Even where enclosures are fitted, noise levels are often still very high. There is a more effective and lower-cost alternative approach.

Accurate diagnosis often makes it possible to reduce the noise at source. In this case, our solution was based on a very precise analysis of the source of the noise energy. This allowed us to more than halve the noise by developing a re-designed cam that not only extended the life of the cam significantly but also reduced operating costs. Coupled with hygienic close shields, this reduced noise levels by 10dB or more at a fraction of the cost of conventional enclosure.

  • hygiene
  • noise control

Pharmaceutical – Food and Drink – Confectionery – new low noise materials

high hygiene and GMP noise control

Coupling new acoustic materials and systems with engineering source control technology is re-defining what constitutes noise control best practice in the food, drink and pharmaceutical industries. Whilst conventional acoustic materials (foam, fibreglass, rockwool) pose an unacceptable hygiene problem, we have invested heavily in the development of new techniques specifically for hygienic applications in clean industries that can be implemented quickly and painlessly – often as an extension to a maintenance schedule. The new generation of noise reducing materials includes…

  • laminated stainless steel from SoundDampedSteel. This highly damped replacement (or retro-fit upgrade) for existing guides, chutes, guards, hoppers etc is hygienic, rugged, low cost and yet can reduce radiated noise by 10dB – 20dB in conjunction with engineering techniques that cut noise at source
  • sound absorbent systems developed by Ecophon that are suitable for use in GMP (Good Manufacturing Practice), high care areas and clean rooms. These can withstand aggressive cleaning regimes, including pressure washing
  • all aluminium sound absorbent micro-mesh that is very efficient at absorbing sound with no hygiene implications

These noise control materials and techniques are ideal for the pharmaceutical, electronic and food and confectionery industries where hygiene is a key requirement.

  • hygiene
  • damping
  • noise control
  • weighing

Weighing Machine Noise Control

Weighing machine noise control

Weighing machines often generate noise levels of 90 – 100dB(A). The conventional approach is to fit partial or full enclosures round each machine. These often produce a noise reduction of only c 5dB(A) (and even an increase at the operator in some cases…) at a cost of the order of £8000 – £15000 per machine – and with the associated access and cleaning problems. We have developed source control techniques that reduce noise levels by 10 – 12dB(A) (typically) with no effect on normal operation, cleaning, hygiene or access – and at a small fraction of the cost of enclosures.

In this case, implementing our techniques reduced the 94dB(A) using the supplied acoustic enclosure down to 82dB(A) (PPE no longer mandatory) with the enclosure removed. This also reduced cleaning downtime from most of a day down to a couple of hours, improving productivity. Successful applications range from confectionery to pharmaceuticals to meat product processing.

  • hygiene
  • noise control
  • fan noise attenuation

Pick-and-Place Suction Fan Noise Reduction – a packet quieter…

Pick and place fan noise reduction

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.

  • hygiene
  • noise control
  • fan noise attenuation

Reducing Noise from Air Transport Fans – higher efficiency…

Air transport fan noise control

Noise levels in a pharmaceutical manufacturing area were 95-100dB(A), dominated by the product air transport fan system. Whilst a traditional high-cost hygienic absorption system could be used to reduce the average area noise level by 5-10dB(A), it would still leave hot-spots of up to 95dB(A) near the air transport fans. As strict hygiene requirements ruled out conventional silencers, novel aerodynamic inserts were fitted inside the fan casings to reduce the tonal noise from these units by close to 20dB with no hygiene or performance implications over the life of the fans.

With the local fan noise eliminated, it was possible to reduce operator noise exposures to well below 85dB(A), reducing the hearing damage risk by around 95%, allowing PPE to be made advisory.

  • hygiene
  • damping
  • noise control

Noise Control for Vibratory Hoppers, Feeders, Graders, Conveyors, Separators…

Bottle vibratory feeder noise damping

The noise from dozens of vibratory feed hoppers and separators in a pharmaceutical plant generating 95 – 99dB(A) was reduced by 22dB via retro-fit modifications to the geometry and the introduction of sophisticated damping. As an additional benefit, the modifications substantially improved product feed and eliminated persistent fatigue cracking. The cost was not only a tiny fraction of the c £100000 required to fit conventional acoustic enclosures, but there was no effect on access/cleaning (unlike acoustic enclosures) and productivity was significantly improved.

A similar approach has also been successfully applied to control the noise from vibratory bottle feeders to give an 8dB(A) reduction at a cost of c£500 and with substantially improved performance and productivity.

  • vibration control
  • HAVS
  • product development

Grass Mowing Machine

dennis grass mower vibration control

Manufacturers are under increasing commercial pressure from their customers to develop low vibration plant. The innovative low vibration handle developed by the INVC for a Dennis Mowers lawn-mower reduced operator exposure from 6m/s^2 down to 2m/s^2 – without compromising mower control. This is a dramatic improvement that would allow operators to use the mower all day without reaching the 2.5m/s^2 Exposure Action Value.

  • vibration control
  • HAVS

Pedestal / Backstand Grinding

Flash removal from hand-held aluminium components generated 32m/s^2 – the Exposure Limit Value (ELV) would be reached in 12 minutes, severely limiting production. Detailed analysis revealed dominant vibration was caused by a pedestal grinder component rest resonance. It was replaced by a floor mounted version that improved the ergonomics and reduced the vibration to 1m/s^2, allowing unlimited use without risk of HAVs.

  • vibration control
  • HAVS

Concrete Mould Ramming Tool

concrete lintel rammer vibration.png

A hand-held Ingersoll Rand sand rammer packing concrete lintel moulds generated 28m/s^2 with a maximum trigger time of only 15 minutes/day before reaching the ramming tool vibration control Exposure Limit Value, seriously limiting production. We designed a mass / sprung balance system that reduced the vibration to 11.5m/s^2, extending the “safe” trigger time to 90 minutes/day. Combined with substantial ergonomic improvements, operator HAVS risk was virtually eliminated and there were large productivity gains. As the whole project was completed within days (no site visit) via information (data, video) forwarded by email, the total cost was a few £hundred, making it self-financing over a few days.

  • vibration control
  • HAVS

Riveting Aluminium Panels

Vibration from riveting on a bench jig posed a very high risk of HAVS. Our redesigned, stiffer jig reduced the riveting time by 50% and the vibration by 25%. This cut the overall operator dose by nearly 90% – improving productivity as a side effect.

  • vibration control
  • HAVS

Impact Wrench Bolt Tightening Vibration

The operator used a spanner on one side of conveyor frames and an impact wrench on the other, producing significant HAVS risk in both hands. We recommended a larger, more ergonomic spanner and a more powerful wrench. These measures halved the vibration dose and significantly improved productivity.

Showing 16 to 30 out of 92