HushKit for Frost Fans

The widespread use of industrial frost fans and blowers are a vital tool for many agricultural industries in the New Zealand to control damage from frost.  Grape growing winery vineyards and fruit orchards in particular can suffer greatly from damage to produce.

The resulting frost fan noise has led to an increase of formal complaints to authorities who have in turn reduced the allowable decibel noise limits putting many operators in serious breach of regulations.

The good news is SprintAero has developed a highly effective and affordable solution … the SprintAero Hush Kit for Frost Fans.

Huskit 6SprintAero Hush Kit for Frost Fans

Developed, tested and built in New Zealand, the SprintAero Hush Kit for Frost Fans provides the best solution available for reducing noise from Vineyard and Orchard frost fans.

Each kit consists of a replacement SprintAero SF50 aerofoil blade set with hub and spinner, a exhaust modification kit and a engine cover noise reducing upgrade kit. This comprehensive frost fan upgrade package has been tested to give a combined total noise reduction down to approximately 46db at our test site just south of Auckland!

In addition to dramatic noise reductions, the SF50 frost fan aerofoil is substantially lighter, stronger and more efficient so not only will you easily meet regulations, but will receive more performance and reliability from your frost fan.

SF50 Frost Fan Aerofoil

The five bladed SprintAero SF50 uses a much improved aerofoil type, this alone cuts the  unwelcome fan noise, very effectively, from between 67 and 72 DB down to 55 db at the required range compared to a standard fan blade assembly from the OEM’s (As tested by Marshall Day Acoustics at our test site).

Reduced Frost Fan Noise

Major gains come from a number of points of difference;

  • Our 5 bladed SF50 frost fan aerofoil moves the remaining noise up to a more pleasant frequency for the human ear which also happens to penetrate much less than the lower frequencies do.
  • A custom designed spinner covering the hub and mountings reduces the noise created by the air being chewed up by the sharp edges and fasteners that would otherwise be pushing through the air with each revolution for no gain
  • An upgraded exhaust system with innovative absorption methods to remove the grumble ( from the engine and the neighbours ).
  • Custom designed engine cover upgrade with airflow control and noise reduction at its core while still maintaining the serviceability required, to reduce the radiated engine noise.

Our independent noise testing, carried out by the world renowned Marshall Day Acoustics company, has shown the complete package output when allied with our SF50a fan system is down to approx 46 db at the required testing range.

Imagine running your SprintAero Hushkit upgraded frost fans and NOT getting complaints from the neighbours or the councils – wouldn’t that be nice?

Increased Efficiency from your Frost Fans

  • With that extra stiffness we are able to move the axis of the blades 10 degrees forward to move the blades away from the mounting pole to minimize interference noise and still increase the throughput of air at least 10% better than the OEM ( as tested by Opus, another well-known and independent testing company.)
  • Custom designed and lightweight composite blade tips that reduce the vortices at the blade ends, thus improving the  efficiency and also lowering the noise still further.
  • The ability to adjust the pitch of the blades to suit the exact requirements of your individual machine at every install allows us to maximise output and minimise noise from each machine, something no other supplier can do at this time.

Onsite testing of the two major competitors frost fan blade systems and found some interesting results. The two blade system was noisest and produced an overall airflow of approx 211 kg/m/sec while consuming around 90 hp to do so. The four blade system was somewhat quieter and produced approx 290 kg/m/sec but for the consumption of over 125 horsepower. So the result is 37.5% more air but for 42% more power so being 4.5% less efficient and therefore drinking more fuel. SprintAero’s HushKit upgrade has been tested by independent and industry recognised companies and proven to be quiet enough to pass all the regulations and have improved airflow as well!

Increased Strength, Safety and Reliability

The construction of the SF50 gives a radical reduction in weight of the blades while giving an equally radical improvement in blade stiffness. This claim is backed by the blades being tested to an aircraft specification by an independent company. OEM Blades are stated as being 21 kg per blade which at 500 rpm means the blade extracting forces are around 16,000 lbs ( ~ 7250 kg ) for each blade the SprintAero blades weigh in at under 5 kg each so the centrifugal loads come in below 22% of the OEM system. The SprintAero blades have also been load tested to an internationally acceptable standard for both extraction and bending forces ( reports available upon request )

  • Dramatically lower radial forces due to as low as 22% of the OEM type, lowering the consequence of failure
  • Proper testing to prove the resistance to failure
  • Much lower polar moment of inertia which lowers the stress on the gears, bearings and shafts etc
  • Much stiffer so wind speed limitations are relaxed to speeds so high you wouldn’t ever want the machine running in those conditions
  • Improved service life and it also lowers the noise output from these components as they are significantly less stressed.
  • The possibility of raising the speed at which the gearbox rotates around the tower to improve the spread of air if required

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We would be happy to help you with any questions about our products and services.
Please call Phil on +64 21 720 180