Fan Blog

Updates and news about Puravents range of drum fans, ventilator fans, wall mounted fans, fume extraction and destratification fans.

Are you Wasting Heat and Energy?

Investing in destratification fans pays back instantly in terms of worker comfort also pretty quickly in terms of £££s as its puts an end to wasting heat and energy. Destratification fans can be retro-fitted to almost every workplace with immediate benefit.

CAT_C3N

Frico 9kW wall mounted fan heater

We recently quoted for a couple of Frico 9kW unit heaters to a client to heat his small manufacturing unit.

We also quoted for a thermostat to control the heaters and help to minimise his energy bills.

TAP_16R

Room thermostat

destrat_fan

Airius destratification Fan

To complete the offering we quoted for a small Destratification Fan to further minimise the bills by returning rising hot air from the ceiling of the factory to the working area (i.e. where the people are).

The client went ahead and bought the heaters and thermostat but did not proceed with the Destratification Fan.

A few weeks later we got a message to the effect that the heaters were working flat-out, the ceiling space was toasty (wasting heat and energy), but the workers were still cold! After some discussion the client decided to buy and install the Destratification Fan albeit with a little scepticism.

Today we got the following message and photographs…..

Hi Bill/Robert

IMG_9724

Two heaters and a destratification fan in use in a small manufacturing unit

You will be happy to know that the Airius 15 destrat fan is working a treat !

Heating is actually switching off now.  Fingers crossed the bills reduce too.

Appreciate the help and advice. Attached photo which you can use if you want.

…and here is the photo they sent, with the two heaters wall mounted with isolator switches towards the right of the photo and the fan hanging from the ceiling joist near the centre.

We have hundreds of heating and ventilation options available on our website so if you require any assistance please do call us to discuss your requirements on 01729 824108. Alternatively email through your enquiry to info@puravent.co.uk or follow us on Facebook or Linked In

HVLS fan or high volume low speed fan. Either way this is the machine to use in order to lower apparent temperature

HVLS Fans For Cooling in Buildings

Introduction to HVLS Fans and apparent temperature

The remarkable thing was that when I visited the  factory making HVLS fans in Italy it was a warm day. Leaving the factory building and walking to the car, the sun was relentlessly beating down and opening the door of the little hire car was like opening a preheated oven. It was only 20 minutes into the journey with the air conditioning running at full blast that the car came down to a comfortable temperature and the internal surfaces settled to somewhere below melting point.

But here’s the thing. All day inside the factory it had been cool and refreshing. Hot outside, yet cool inside.

As I drove back to the airport I reflected that with near 3 decades in the air business having sold and supplied 1000s of fans, I had never given thought to, nor even heard of, the concept of apparent temperature. It had been a good day – learning more about HVLS fans and discovering the nuts and bolts about apparent temperature.

What are HVLS Fans ?

HVLS fans  are so called for thier High Volume and Low Speed

HVLS fan or high volume low speed fan. Either way HVLS fans are the machines to use in order to lower apparent temperature in large buildings

HVLS fans are characterised by two elements – firstly High Volume, the HV bit. The Evel range of HVLS fans runs from the smallest with 1.4mØ blades moving 41,000m3/hr of air through 15 models to the largest with 7m Ø blades moving 850,000m3/hr. By any reckoning that is a huge airflow.

The second element is Low Speed, the LS bit. It refers to both the speed of the fan blades and to the air discharge velocity. As an example the largest in the range that moves the whopping 850,000 m3/hr rotates at a sloth like 50 rpm. In other words at full speed it takes over a second to complete a revolution. To someone like me used to fans on a direct drive doing 960 rpm or more it took a moment or two to understand just how slowly they move. Their slowness is however a good thing. Because of the lazy sweep of these vast blades the air speed that they create is slow so instead of a busy little throw of air from a normal fan that blows your socks off, the vast air flow from these HVLS fans gently washes over you.

It is difficult to adequately describe the effect. The area affected by the airflow from one HVLS fan is very large, and wherever you walk in this area you are aware of refreshing air movement, yet in no way are you ruffled by it. This constant gentle air movement is refreshing and it does make you feel cool and comfortable.

What is Apparent Temperature?

On a still hot day the mercury can be say 35°C and it will feel hot and uncomfortable, particularly if it is humid. If however there is a gentle breeze the mercury will still be 35°C but it will feel cooler. Evaporation of moisture from our skin cools our skin so that we feel cooler and indeed when it is on a continuous basis, we are kept cooler. In other words, when there is air movement our body’s’ natural cooling mechanism is more effective.

The relationship is straight forward so that apparent temperature changes as follows;

•   Increases with increasing humidity and visa versa

•   Decreases with air speed and visa versa

So apparent temperature and perceived temperature are one and the same thing and they differ from dry bulb temperature dependant on air speed and humidity.

Knowing that it is a hot day outside yet being inside a big building where you feel quite comfortable is a slightly weird experience – not cool exactly but not too warm either, and where there is a constant sensation of air movement throughout the building. It makes for a very pleasant working environment.

With no HVLS fans there is no air movement and the room condition is uncomfortable

When there is no air movement the set point of 27°C and 50%RH falls outside the comfort zone

With HVLS fans producing a net air velocity of 1m/s the room air is comfortable

When there is 1m/s air movement the set point of 27°C and 50%RH falls easily into the comfort zone.

 

What makes Evel HVLS fans a bit special?

Essentially there are only 4 main bits on a HVLS fan, the motor, the mounting, the blades and the controls.

Evel HVLS Fan Motors. Changes to European regulations on energy efficiency in recent years has resulted in many machines now being driven by EC (electronically commutated) motors. These brushless motors are without doubt more efficient and more readily controlled than old AC induction motors. The motors on the Evel HVLS fans are all brushless EC type but the clever bit is that they are direct drive. No belts, no gearbox – just a shaft direct from the motor to the fan hub assembly.

big motorWhen you have been used to 4 pole induction motors that whizz about 1450 rpm under load, it takes a bit of head scratching to realise that the motor of the biggest fan in the range can is spinning at the same speed as the fan blades i.e. 50 rpm But it is even more daunting that this is its maximum speed, and in fact taking a 0-10v control signal, it can be controlled to spin at much slower speed if required. The start-up on these motors is sublime and not unlike a Rolls Royce gently pulling away to hit walking pace. Loads of torque at minute speed.

The motors only come in a couple of sizes basically the larger fans get the bigger one and the smaller fans get the smaller motor. But the clever bit is that each motor is programmed to a operate to suit the fan size and blade profile that is being fitted to it. Each fan model has a lengthy set of parameters that must be programmed into the motor so that it runs and the very best efficiency. Each complete fan can be connected via a controller to the internet. This is useful for periodic checking and also in the remote event that the HVLS fans brushless motor goes wrong because it can be interrogated remotely and its operating parameters can be compared to design values and even temperature of the casing and shaft can be seen.

Evel HVLS Fan Mounting. There a number of bits to the mounting arrangement and none of them is exactly lightweight.

Evel HVLS fans are mounted with a fail safe support cradle

The support structure is a thorough fail safe design.

The motor is cradled by a pair of inverted U-shaped brackets and these support a base plate to which the base of the motor is bolted. The impeller hub is bolted to end of the shaft with a number of bolts. These are designed to be tightened to different torques so that the weight is supported by the two tightest bolts but should they both fail other bolts will take the weight. A further layer of fail safe design is in the form of a pair or brackets bolted to the base of the motor which cradle but do not touch the rotating shaft. If the hub becomes part detached because all 3 bolts have failed these cradle plates will support the blades and prevent them detaching fully.

The hub comprises of a ‘spider’ assembly which comprises of 2 plates each of which has 5 spurs. These twin spider plates are so designed such that if one spur cracks then the other is perfectly touch enough to support the blade on its own.

Mounting of the complete fan assembly is facilitated by a number of optional fittings which are selected depending on the design of the roof structure.

aerofoil tip

Engineered aerofoil profile with moulded wing tip to ensure the air does not spill from the end of the blades

HVLS Fan Blades. It is interesting to note that HVLS fans come with a variety of blade quantities. Early ones had 10 blades, others have 8 or 6 blades. The Evel range of HVLS fans has 5 blades. The choice of the number of blades is the subject of much research. For a given fan speed, too many blades and you find that any one of the blades is trying to bit into turbulent air from the preceding blade. Too few blades and the fan will not move as much air as it could if it had another blade. In other words like so many things in engineering the game is to work out what the top of the bell curve for the parameter you are designing. The engineered balance between turbulence and maximum effectiveness for the speed that these aerofoil blade revolve results in a design that uses 5 blades, each with a upturned wing tip designed to stop air escaping the sweeping movement of the aerofoil profile of the blade.

Control. There are a number of control options to the Evel HVLS fans. All work from a 0-10v speed control signal but there are various options for added control sophistication and system monitoring via modbus.

What About The Racket?

It is a fair question. Moving say 850,000m3/hr of air is bound to be massively noisy. At least that is what I thought before visiting the factory in Italy. Well used to the sound of blades beating air into submission and of whirring motors and humming gears, I fully expected something to fill my ears.

I admit that after a former life in uniform  with the occasional loud bang, hearing pins drop is not exactly my forte. I listened, I felt the refreshing wash of air movement, and I think I detected a faint hum. My host said that noise was not the fan but was coming from the factory next door. Not convinced, I ambled across the factory floor towards the back wall adjacent to the next door property and right enough the hum increased in volume – it was the factory next door. Of the gently sweeping HVLS fan above my head I heard diddly squat.

With the lack of noise, the slowly rotating motor and blades and the gentle even breeze they created, the effect on the senses was sublime.

Make your environment comfortable and take your air space to the next level with Evel HVLS fans from Puravent.

Call us for more information or help.

HVLS fans in a fitness studio. A breeze in an environment like this - Bliss

HVLS fans in a fitness studio. A constant breeze in an environment like this – Complete bliss !

 

Heat Stress in Poultry- a financial disaster that can be avoided

Heat Stress in Poultry – What can you do?

Heat stress in poultry – What can you do?

Eleven of Plant Earth’s hottest years ever recorded have been in the last 20 years. This year the highest UK temperature ever was recorded at Cambridge – 38.7°C and the trend indicates records will be broken again and again in coming years.

Estimates vary, however it is widely assumed that each adult bird produces 10 – 20 watts of heat. On a hot day the roof of a poultry house can rise to 60°C due to the combined effects of the sun on the outside and rising heat from the poultry on the inside. If the body heat of a bird rises from 41°C (normal) to 45°C the bird will die.

Heat stress in poultry (and all other livestock production) is set to become a more frequent and an even more severe problem than it is today. Although it is a serious stock welfare and financial issue to livestock producers, it is also an issue with effects that can be minimized with preventative measures.

Where does the heat stress come from?

Apart from external heat sources the poultry produce a good deal of heat themselves as a result of metabolism – body maintenance, growth and egg production all produce heat which under normal weather conditions the heat is lost through :-

  • Radiation – heat is lost from the body of the bird by radiation provided the surrounding surfaces are at a lower temperature than the bird. Conversely hot roofs and walls will radiate heat towards the birds.
  • Convection – heat radiated from the bird will naturally rise towards he ceiling of the shed – where an outlet for the heat must be provided. Ventilation will assist this provided the airflow is high enough to break down the boundary layer of still air around the bird’s body.
  • Conduction – If the bird is in physical contact with a surface at a lower temperature than it’s body, heat will transfer to the cooler object.
  • External sources – Heat and humidity caused by the ambient weather conditions outside the poultry shed.

As well as sources of heat it is important to remember that heat stress results from a combination of temperature and humidity. The heat stress charts always pitch temperature on one scale against humidity on the other. For a given ambient temperature, the level of discomfort to the birds will be greater on high humidity days than if the humidity was lower.

What are the signs of heat stress in poultry?

  • Birds will pant at up to 230 times a minute in order to drive off heat in the form of water vapour – hence the need for plenty of cool drinking water for re-hydration. If the conditions are highly humid the panting of the bird is ineffective resulting in a very rapid increase in stress levels.

    Interior of a typical poultry shed

    Interior of a typical poultry shed

  • Raised wings in order to expose the featherless underwing area from which body heat (carried to the skin surface by blood vessels) may radiate.
  • Pale combs/wattles.
  • Lethargy.

In worst case:-

  • Diahorea.
  • Seizures/convulsions.

Other consequences of heat stress in poultry.

Unless measures are taken producers will see:-

  • Reduced growth rates in younger birds unable to react to rapid changes in temperature and humidity.

    Poultry discomfort chart by tempeture and humidity

    Poultry discomfort chart by temperature and humidity

  • Reduced egg production in more mature birds.
  • Darkening of the skin colour as more blood is diverted to the surface to combat the body heat rise.
  • Increased mortality in all birds but especially in the younger birds.

Measures to reduce heat stress in poultry

  • Make sure birds have cool, clean water.
  • Add electrolytes to water. Electrolytes help to balance the birds’ own electrolytes, plus they will drink more water.
  • Provide protection against direct sunshine and ensure the poultry house’s exterior structure is insulated and heat reflecting rather than heat absorbing
  • Reduce overcrowding and other forms of stress such as the presence of children, dogs, noise etc.
  • Provide adequate ventilation to remove the rising heat created by the flock.

Importance of good ventilation

Natural ventilation is not adequate in extreme circumstances. When high temperature is combined with high humidity all animals will naturally work to regulate their own body temperatures by measures such as sweating, panting, moving apart, reduction of food intake and activity etc.

It is important under extreme conditions to turn over the whole air volume of the shed regularly and also recirculate air within the shed when internal air distribution is poor.

Remebering that heat stress in poultry is in part a factor of humidity, it is important to realise that humidity levels will be higher inside the  poultry shed than outside. This is because of the littering of the stock and their sweating. Each bird delivers both heat and moisture load to the inside air. Although you can not change the humidity outside of the shed, with sufficient ventilation you can ensure that the effect of humidity on the heat stress level is no more than the outside ambient level.

Maximum_Ventialtion_rates_(m3_h_per_1000_birds) essential to prevention of heat stress in poultry

Maximum ventilation rates (m3/h per 1000 birds) – source DEFRA. The through flow of air based on these rates is essential to prevent heat stress in poultry

Main ventilation fans can be placed either:-

  • In a side wall preferably a North-Facing wall to push fresh air into the building – hot air would in this case exit the building through louvered  vents in the Apex or opposite end of the building.
  • In the Apex of the building to draw hot air out – fresh air would then enter through louvres in the walls (preferably North-Facing).
Box inlet fans - poultry house. An essential part of the shed infrastructrure to prevent heat stress in poultry

Internal view of Louvered Main Ventilation Fans

Suspended fan - part of the solution for heat stress in poultry

Suspended fan – poultry house

Puravent’s main recirculation ventilation fans are available in 3-blade or 5-blade versions, with or without inlet cones and in a wide variety of diameters (915mm to 140mm). We also offer panel fans range in diameter from 200mm to 920mm and in power from 60W to 1.8kW. They are also available in single phase (230v) or 3-phase (440v). All have IE2 or IE3 energy efficient motors.

Multifan with bird guard

Main ventilation fans – Optional cone for greater air flow

Puravent’s Internal recirculation fans should be placed  strategically around the shed so that fresh air does not short-circuit directly to the hot air outlets leaving discreet areas such as corners of rooms with no air turnover. These panel fans range in diameter from 200mm to 920mm ad in power from 60W to 1.8kW. They are also available in single phase (230v) or 3-phase (440v). This range covers air flows from 650m3/h through to 25,500m3/h.

V_flow_fans create disruption to linear flows down the poultry house

Typical V-Flo fan

V-flo fans can take air from above and below and throw it out to the sides of the shed. They are a great tool for the prevention of heat stress in poultry

V-Flo fan air flow patern

V-Flo fans in poultry application

As well as moving air through poultry buildings the air needs to be disrupted as it transits the building so that air movement reaches all of the corners and edges of the building.

Another method of minimising short-circuiting from inlet-fan to building-exhaust (thereby ensuring all the birds receive the benefit of the ventilation), is to create turbulence by the introduction of V- Flow fans. These ensure that air passing down the poultry house is driven out to the sides of the building as well as passing down the length of it.

Prevention of heat stress in poultry, is something that we know about and can help with. To view the full range of fans visit our website www.puravent.co.uk or call us on 01729 824108 to discuss your specific requirements.

 

Intrinsically Safe Ventilation Fans

Intrinsically Safe Ventilation Fans

Ventilation in confined spaces or hazardous environments is a ‘no-brainer’ and reliable and safe equipment is essential. This is where intrinsically safe ventilation fans come into their own.

Intrinsically safe ventilation fans are ideal for work in confined spaces as well as in association with welding, concrete cutting, demolition. The same equipment may be used during remediation work following flooding to dry out buildings or simply provide fresh air to work areas as needed.

Intrinsically Safe Ventilation with Compressed Air

Clustajet Intrinsically Safe Air Mover

Clustajet Intrinsically Safe Air Mover Range

Puravent’s range of Clustajet of Intrinsically Safe Ventilation fans are as safe as it gets. With capacity ranging from 765 to 5,270m3/h, no moving parts or electric motor and driven by compressed air, they are ideal for use in confined spaces, and in damp or wet locations. The Clustajet range of intrinsically safe ventilation fans include 4 sizes ranging in diameter from 4″ to 12″.

12" Clustajet Intrinsically Safe Ventilator

12″ Clustajet Intrinsically Safe Ventilation fan… …or should it be called an air mover?

But to call them a fan is wrong, because they dont have any blades, so perhaps they are more accuratly described as ‘air movers’. Instead of fan blades they have eductor nozzles where the idea is that the compressed air is discharged from the nozzle in a way that maximised the air to air friction in the duct, and which induces the air in the duct to move in the same direction as the discharged compressed air.

The Clustajet units are generally used to extract air from confined spaces to allow fresh air to replace the extracted air, and where there are duct runs of more than 25m, we recommend a unit for each 25m of ducting.

With no moving parts to cause sparking, these units are safe for use in problem applications, such as with air laden with dangerous gases, dust or solvent vapours.

Puravent’s VAF intrinsically safe ventilation fans extends the operating range to 7,500m3/h and is the ideal in confined spaces or in zones where use of electricity is forbidden. Available in 300 and 400mm diameter, the double wall construction protects the inner casing giving extended product lifetime. The bodies on these intrinsically safe ventilation fans are made from a dual wall polythene rotational moulding allowing it to withstand the knocks normally found in industrial use – a common cause of failure with traditional steel cased fans.

VAF-400 Pneumatic Ventilation fan. Pneumatic ppwered fanThe 400mm diameter VAF-400P – FRL ventilator, weighs 13 kg and provides 7500 m3/h of air flow, driven by a pneumatic motor developing 1.1kw of power. It is built to provide maximum power where it is needed and it is the ideal large air flow  intrinsically safe ventilation fan. Intrinsically Safe Ventilation using a VAF300P-FRL pneumatic fan

The smaller variation on the theme is the VAF-300P – FRL intrinsically safe ventilation fan.  With 3400m3/hr of air flow it is a bit more portable that the 400mm unit and is suitable to ventilating smaller hazardous enclosed atmospheres

One of the big benefits of using compressed air to power a fan is that it is very, very controllable. Electrically driven ventilation fans are almost always an on/off affair, however the regulator valve on the compressed air inlet to the VAF pneumatic fans allows the airflow through the fan to be steplessly adjusted from 0 to maximum flow. It means that beyond the obvious applications in hazardous confined spaces, that they also have application in some process applications where fine adjustment of airflow is essential

It can out perform conventional metal bodied fans several times over. In fact we are so confident in the VAF-400’s quality then VAF offer it with an industry beating 10 YEAR warranty upgrade on the fan body.

Stacked 300mm dia. VAF Ventilators

Stacked 300mm dia. VAF Ventilators

VAF300_pneumatic fan and duct.  Intrinsically Safe Ventilation at its bestAll VAF models, both the pneumatic powered and the electrically powered versions can be stacked for ease of storage and to give maximum airflow from minimum floor space.

The high pressure capability of this fan make it very capable of use with up to 3 lengths of our 7.5m anti-static flexible ducting.

 

For further information and/ or help in sizing, please email us at puravent@gmail.com or call us on +44 (0)1729 824108

 

HVLS Destratification Fans – A Guide

High Volume Low Speed destratification fans (better known as HVLS destratification fans) are able to provide great improvements in working environments, customer environments and  livestock housings, and better operating conditions for many types of machinery. Due to their whisper-quiet operation (<60dBa) the Evel HVLS destratification fans are applicable across a wide range of environments including for example – restaurants, hotel lobbies, large open plan office places, atriums, conferance centres, warehouses, manufacturing environments and livestock buildings.

What is ‘stratification’ of air?

Evel HVLS destratification fans

HVLS Destratification Fans ranging from 2.5m to 7m diameter are available

Stratification of air is due to the fact that hot air rises, leading to the temperature at ceiling level being higher than at ground level. It is generally accepted that in rooms with stratified air, the temperature differential is typically 2-3°C per 5m height but can be as much as 1°C/m height in some circumstances.  In the worst case, this means that in a 10m high room the difference between temperature at floor level and ceiling level would be 10°C. To achieve a comfortable working environment of say 18°C therefore entails heating the ceiling to 28°C in this circumstance and the higher the ceiling the greater the potential temperature differential, and the greater the likely savings from implementing effective thermal destratification fans.

How do HVLS destratification fans work?

HVLS destratification fans take in the warmer ceiling air and transport it to the floor in a slow-moving column to create a better working environment and greatly reduce total energy consumption. In winter the most significant benefit is a considerable reduction in the cost of heating to create the optimum working/storage environment. During summer months HVLS destratification fans provide low-cost ventilation, reducing or eliminating the need for air conditioning.

When are HVLS destratification fans used?

Evel HVLS Farming 1

HVLS Destratification Fan in use in a livestock application

These fans come into their own in larger applications where there is an economic advantage to using HVLS fans rather than typically up to 7 smaller conventional destratification fans. The increased cost per fan of HVLS fans will be offset by lower installation costs (particularly power and control cabling), lower ongoing operating costs (due to far more efficient motors and responsive control systems) and lower future maintenance costs (due to lower speed and automated, variable speed operation).

Where are HVLS destratification fans used?

In retail or manufacturing situations it is necessary to maintain a comfortable environment to maximise customer enjoyment and / or employee productivity. In high-tech environments a stable controlled environment is required for efficient operation of electronic equipment.

In warehousing it is often necessary to maintain certain air quality standards including temperature and humidity in order to maintain the quality of the stored materials. Similar requirements apply to indoor sports arenas. HVLS destratification fans are ideal for such applications as they are able to respond rapidly to changing environmental conditions.

Enclosed or semi enclosed livestock buildings such as poultry sheds, livestock wintering buildings and cow milking parlours will enjoy the benefits of energy savings and enhanced productivity and improved animal welfare when HVLS destratification fans are put in place.

‘Evel’ range of HVLS destratification fans

All Evel HVLS destratification fans incorporate brushless motor technology with integrated inverter to give optimum efficiency and also allowing remote control and/or monitoring of more complex environments. Fans may be controlled remotely as individual units or may be grouped together as a system and controlled by a central controller.

  • The ‘WD’ range – This range is particularly though not exclusively applicable to the Hotel / Restaurant / Small Commercial markets. These have  5 ‘Selig’ profile fan blades with a diameters of  2.5 – 4 metres rotating at between 160 and 250rpm. These are suitable for ceiling heights up to 7 metres.
  • The ‘WZ’ range – This range is aimed at the Industrial / Large Commercial / Farming markets. These have  5 ‘Naca’ profile fan blades with a diameters of 2.5 – 7 metres rotating at between 38 and 250rpm. These are suitable for ceiling heights up to 12 metres.

Sizing your system

Selection of the most applicable size and the correct quantity of fans to gain maximum cost effectiveness in any particular situation is complex, because there are a number of other variables that conribute to the overall calculation.These include,

  • Ambient temperature outside
  • Materials of construction and how well insulated the building is
  • The efficiency of the heating system
  • The control accuracy of the heating system
  • The actual temperature differential pre destratification
  • The effectiveness of the destratification fans
  • The running costs of the destratification fans
  • The pricing structure of the running cost to your heating system

Help and advice

If you would like to find out more or to get advice on reaching an ideal air circulation system for your application then email us at puravent@gmail.com or call us on +44 (0)1729 824108

Oscillating Wall Fans – keeping everyone cool

oscillating wall fans – not just for fitness studios


Cyclone oscillating wall fans
are a popular choice for creating air movement and ventilation in a variety of applications whether they be small or large rooms, sheds, industrial, or livestock applications. When the sun gets up, the heat gain on industrial and commercial buildings can be spectacular, making the building quite

oscillating wall fans

Heavy Duty Cyclone Oscillating wall fan.

When the outside temperature is in the 20’s, the temperature inside some buildings can easily reach into the 30’s. Although there is no legal minimum or maximum temperature in the work place in the UK, the HSE recommends a range between 13 and 30°C as being comfortable.

Most people find it uncomfortable to be in, or work in, an indoor environment much above 24°C. But the solution that increasingly being used is industrial wall mounted fans. When they are put in key positions to blow over crowded areas, or work stations, they can bring welcome relief to people who would otherwise be wilting in the heat. We find that they are very popular in shops, health clubs, gyms, and as we have recently discovered, in animal enclosures!

Wall mounted fans can be used in conjunction with open doors and windows to move air around the building and can, if cleverly placed, can induce air movement through the building, bringing cooler outside air in to replace the hot inside air. In addition to the cooler replacement air, people will feel air movement over their skin and thus feel cooler as evaporation from skin is increased.

 cyclone Oscillating wall mounted fans for Giant Galapagos Tortoises

tortoises appreciate cyclone wall mounted fans too

Dirk the Giant Galapagos Tortoise

We all can appreciate a bit of air movement in a warm environment, but as it turns out Giant Galapagos Tortoises also like some air movement to keep their living environment fresh.  Dirk the 70-year-old Giant Galapagos Tortoise is the largest of his kind in the UK. He happily resides at Crocodiles of the World in Oxfordshire, amongst other smaller reptiles, mammals, exotic birds, and 17 of the world’s 24 species of crocodiles. Dirk and the other Giant Galapagos Tortoises at Crocodiles of the World have Cyclone oscillating wall fans to ensure that the there is constant air movement round their enclosure which helps prevent stagnant air pockets, damp and rot.cyclone wall mounted fans

The spectacle of the crocodile feeding time is an understandably popular one and at busy times visitors may have a few minutes to wait before seeing Hugo and the other crocodiles. Luckily the waiting area for seeing the crocodile feeding has a number of Cyclone oscillating wall fans gently moving the air around to help visitors keep cool for those few moments of waiting. Once in to see the crocodiles feeding it is not a great idea to throw things in the enclosure as the management take a firm line on such antics.

Hugo loves cyclone wall mounted fans

Hugo the croc

Air circulation is one of the most important factors in keeping livestock and zoo animals. Whether it be cattle, pigs, poultry or indeed a Giant Galapagos Tortoise, proper movement of air can keep the enclosure healthy, and the animals comfortable. In stark contrast stagnant air mean that enclosures can be sources of infections caused by mould, damp, rotting vegetation and bedding.  An efficient cycle of moving air can keep moldy areas, and airborne infections at bay.

If you have any further queries on cyclone oscillating wall fans or their applications, please contact our UK-based office on 01729824108, or at info@puravent.co.uk.

If you want more information or to have a look for yourself at the animals mentioned here, take a further look at Crocodiles of the World’s website at https://www.crocodilesoftheworld.co.uk/

Giant Galapagos Tortoise loves oscillating wall fans

Case study in simple office cooling

Hot Office Problem
It’s not uncommon to have a south-facing window, and as much as we like the view from our office, there is a problem. In summer as the morning progresses we can feel the heat gain through our south-facing window as the sun reaches its zenith. For the rest of the day the office remains hot and can become stifling. Work rate decreases. Mistakes increase 😡

Office Cooling Solution Step 1
Rather than get an air conditioner to rattle away in the corner, we decided to lower the window blind before mid morning on the big window in the office and to use natural ventilation. So we opened the windows. Both windows are on the south side so whilst it was an improvement the air movement through the windows was limited 😐

Office Cooling Solution Step 2
The office has its access door from outside on the east side of the building. So we opened it and held it open with a bungee. Soon we had doors and windows banging shut as air rushed in or out of the office. Whilst the canister of bungees was out, it seemed like a good idea to use some more bits of hooked elastic to hold the internal doors and the toilet window open. Great. No more banging windows or doors and reasonable air flow though the office. With only a slight breeze outside we get outside air (which is always cooler than inside air,) flowing through the office 🙂

But There Is Still A Problem
The recent hot weather has been from a ‘blocking high’. It’s because the jet stream is well above the UK that there is a large area of high pressure sitting over the British Isles. Not only does this high pressure give us clear blue skies and hot weather, it also means that there is precious little wind or even a light breeze. It means that our office does not have enough air moving through even with doors and windows open 🙁

Office Cooling Solution Step 3
Seeing that a small part of our business is the supply of wall mounted fans it seemed like a good idea to use one of these fans in the office. It was the clever placement that made it really work. The office is long and narrow and the fan was mounted at one end near the door. With the oscillation function switched off it was left set at an angle which helps to pull air though the doorway from outside and blow the air through the length of the office. Bliss – fresh relatively cool air flowing through the office even when there is no breeze outside 🙂

And here is a plan view of our office complete with ‘cheap as chips’ office cooling…

office cooling with natual ventilation and a wall mounted oscillating fan

Effective office cooling with natural ventilation and a wall mounted oscillating fan….Genius!

You to could probably work wonders cooling your work place with a wall mounted fan. Heres the line up that we offer…

The Cyclone 45T-W 18"Ø wall mounted oscillating fan

The Cyclone 45T-W 18″Ø wall mounted oscillating fan

The Cyclone 50W oscillating wall mounted fan

The Cyclone 50W 20″ Ø oscillating wall mounted fan

The Cyclone 650T-W 26"Ø oscillating wall mounted fan

The Cyclone 650T-W 26″Ø oscillating wall mounted fan

The Cyclone 750W 30"Ø oscillating wall mounted fan

The Cyclone 750W 30″Ø oscillating wall mounted fan

 

About 50Hz And 60Hz Machines

50Hz or 60Hz?

The majority of power outlets across the world operate 50Hz (220–240 V), ranging from majority of Europe and Asia, Africa, Australia, Russia, and South-Southern America. However, Northern America, and Nothern South America, operate a frequency of alternating current at 60Hz (100–127 V). To most, this is not new information, but how many can actually answer- why the difference?

The waveform of 230 volt, 50Hz compared with 110V, 60Hz

The waveform of 230 volt, 50Hz compared with 110V, 60Hz

When looking at the choice of grid frequency (assuming both voltage levels are the same), there can be seen to be no particular major advantages between either frequencies, with both being quite similar from an electrical perspective. Where they differ, however, is from a design perspective. Simply, 60Hz supplied to a motor makes it rotate faster compared to it being supplied by 50Hz.

It used to be easy, insofaras machines with motors would be able to work on either 50 or 60Hz, however as electric motors have developed over the years to become increasingly efficient, it seems that they are also more fussy about the frequancy or the supply. These days a machine that can run on both frequencies is a rarity and it is typical that they either run on 50Hz or 60Hz, but not both.

Historical Influences

Choices over frequencies does however have historical reasons. Early on in the history of electricity, the norm was set with Thomas Edison’s General Electric company distributing direct current (DC) electricity at 110 volts in the United States (U.S). With this, Nikola Tesla introduced three-phase alternating current (AC) at 240V. This allowed for three slightly out of phase alternating currents (AC) to combine and even out great variations in voltage occuring in AC electricity. With this, Tesla conclued that 60 cycles per second (60Hz) was the most effective frequency. However, due to safety reasons, reduced the voltage down to 120V. With this, 60Hz became the standard for the United States and Americas.

Over in Europe, German company AEG invested in generating electricity at 120V/ 50Hz instead of 60Hz to better fit their metric standard, and the result became the norm in mainland Europe. Post World War II, Europe switched to 220V for better efficiency in electrical transmission, and simulatensously, Great Britain changed from 60Hz to 50Hz to follow the European lead. What could have been an expensive switch-over was averted because few people possessed electrical appliances at this stage. However, at this stage a large portion of U.S consumers possessed electrical appliances and such a switch-over would not be viable. A comprimise was concluded with 240V being able to be introduced to a house where it could be split to 120V to power most appliances, whilst certain household appliances such as the electric stove and electric clothes dryer, would be powered at 240V.

Today, there are still a small minority of countries split between the two. For example, all of Japan runs on the same voltage, however the frequency differs from region to region. Eastern Japan (including Tokyo), uses 50Hz after purchasing electrical generators from the German company AEG in 1895. A year later, American company General Electric, provided 60Hz generators for cities in western Japan (including cities such as Osaka and Kyoto).

electricity_map jap

Japan’s (in)compatable power supply grid

Brazil faces a similar situation- despite the country running primarily on 60Hz, most states run between 110V and 127V AC electricity, whilst the northeast of the country run 220-240V (along with majority of the hotels spread all over the country)

Interested in products catered to 60Hz?

There seems to be a slight bend in the rule however. Majority of offshore vessels and platforms run off 60Hz, no matter where they originate or are manufactured. Ranging from oil rigs in the North Sea to the ships deployed by the Royal Navy (*excluding DC ships*), most of these run off 60Hz. The offshore market for 60Hz fans and other 60Hz machines has ensured that we have adjusted our product range to meet this requirement.

Here is a highlight of some of the products ranging from 60Hz fans, 60Hz fan heaters, 60Hz basket fans and 60Hz recirculation fans. The range of 60Hz that are either available in a 60Hz variant, or can be built to order for connection to a 60Hz supply.

60Hz fan options and 60Hz fan heaters available from stock

DVG-T/H Roof 60 Hz Fan

DVG-T/H Roof 60Hz Fan

DVV-EX Roof 60 Hz fan

DVV-T Roof fan

AJR jet 60 hz fan

60Hz AJR jet fan

BF-W Wall mounted 60 Hz fan

BF-W Wall mounted fan

Elektra 60Hz fan heater

Elektra 60Hz fan heater

Panther wall mounted fan heater can be supplied with a 60Hz fan

Panther wall mounted 60Hz fan heater

130cm basket 60 Hz fan

Vostermans Basket fan

Multifan Recirculation 60 hz fan

Multifan Recirculation fan

vflo fan available in 60hz

60Hz V FLo fan

water fed fan heaters available in 60 Hz

60Hz LTHW Unit Heater

AXCBF-EX ATEX certified bifurcated medium pressure axial 60 Hz fan

AXCBF-EX bifurcated axial fan

Multifan Tube mounting 60 Hz fan

Multifan Tube mounting fan

 

Machines which can be built to suit 60Hz supply

VRF range of desiccant dehumidifiers can be built as a 60Hz version

60Hz VRF Desiccant dehumidifier

MCM air conditioners are available in 60 Hz

60Hz MCM air conditioner

AD range of evaporative coolers can be built as 60Hz verions

60Hz Evaporative coolers

 

With that in mind, if you have any questions on purchasing a product that runs on 60Hz from this list or more from our range, (including its application), contact our specialists at info@puravent.co.uk or call our UK based office at 0845 6880112.

 

 

 

ATEX fans and Explosive Environments

Explosion Proof Fans

atexs. ATEX in explosive environments

Puravent’s range of ATEX fans

What is often misunderstood is what exactly is a ‘potentially explosive environment’, and where would you actually need an ATEX fan in an explosive environement, compared to a fan not designed for these sorts of applications. Firstly, explosive atmospheres can be occur in environments where there are flammable gases, mists or vapours, or combustible dusts. With enough of one of these substances mixed with sufficient oxygen in the air, the result is potentially explosive, needing nothing more than the spark from an electric motor or closing switch to cause an explosion. The costs associated to such an occurrence can cause not only significant damage, but also serious injuries, or loss of life. Therefore, the need to prevent releases of certain dangerous substances which can create explosive atmospheres and the need to prevent sources of ignition, are two important ways to reduce the risk. This can be done by using the correct equipment and understanding the dangers and regulations associated. Equipment used in ATEX zoned areas is required to be suitably certified for use the that particular category of zone. Likewise fans used for moving air or for pneumatic conveyance of powers are no different and also need to be certified.

Explosive Environments and Regulations

The Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) outlines the required duties for employers to enforce in order to eliminate or control the risks from explosive atmospheres in the workplace.

DSEAR defines an area where an explosive atmosphere may occur that requires special precautions to protect the health and safety of workers and enivornment as
hazardous. An area where an explosive atmosphere is not expected to occur in quantities that require such special precautions is deemed to be non-hazardous.

What is an Explosive Atmosphere?

According to DSEAR, an explosive atmosphere is identified as the mixture of dangerous substances (gases, vapours, mist or dust with air), under atmospheric conditions. With contact to ignition, combustion spreads to the entire unburned mixture and can result in explosion and harm to the workplace. These atmospheric conditions present are commonly referred to as ‘ambient temperatures and pressures’, which is temperatures of –20°C to 40°C and pressures of 0.8 to 1.1 bar.

Where can Explosive Atmospheres occur?

Typical ATEX zoned area in powder handling facility. ATEX fans

Typical ATEX zoned area in powder handling facility

  • Work places which produces and store foodstuffs (flour, cereals, grains, etc.) such as (powder silos, warehouses);
  • Farms;
  • Painting workshops (including vehicle spray painting workshops);
  • Carpentry workshops;
  • Petrochemical plants;
  • Fuel, gas or solvent storage and handling facilites
  • Laboritories and research facilites
  • Energy production plants (power stations);
  • Pumping stations;
  • Holds of cargo ships;
  • Within big fuel tanks/ drums and road tankers;

    refinery. ATEX fans

    Petrochemical facilities are typically covered with ATEX gas zones.

  • Underground and surface mines.

Employers hold the responsibility to classify these potentially explosives areas into zones. DSEAR provides a ‘ formula’ to the classification of each product. This can be broken down to see what environment the product is designed for. In regards to ATEX fans, the categories and ratings can be seen below. For further information on the protection ratings, refer to the 2002 Dangerous Substances and Explosive Atmospheres Regulations.

 

 

 

Identification for atex explosion proof fans

Zoning Definition and Equipment Suitability

Zone Description

Equipment Suitability

 0
 A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapour or mist is present continuously or for long periods or frequently. 1G 
 1 A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapour or mist is likely to occur in normal operation occasionally. 2G
 2 A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapour or mist is not likely to occur in normal operation but, if it does occur, will persist for a short period only. 3G
 20
 A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is present continuously, or for long periods or frequently. 1D
 21 A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is likely to occur in normal operation occasionally. 2D
 22 A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is not likely to occur in normal operation but, if it does occur, will persist for a short period only. 3D


Types of Protection

Gas
Dust
TYPE ATEX CODE STANDARD
General Requirements EN 60079-0
Intrinsic Saftey Ex ia and ib EN 60079-11
Increased Saftey Ex e EN 60079-7
Flameproof Ex d EN 60079-1
Pressurisation Ex p EN 60079-2
Powder FIlling Ex q EN 60079-5
Encapsulation Ex ma and mb EN 60079-18
Oil Immersion Ex o EN 60079-6
Type n Ex n EN 60079-15
TYPE ATEX CODE Standard
General Requirements EN 61241-0:2006
Protection by Enclosures tD EN 61241-1:2004
Protection pD EN 61241-4:2006
Intrinsic Saftey iD EN 61241-11:2006
Encapsulation mD EN 61241-18:2004


Groups

I Electrical equipment intended for use in mines susceptible to firedamp~
II Electrical equipment intended for use in places with an explosive gas atmosphere other than group I
III Electrical equipment intended for use in places with an explosive dust atmosphere other than group I

Gas Group

IIA Propane
IIB Ethylene
IIC Hydrogen/ Acetylene

Dust Group

IIIA Combustible flyings
IIIB Non-conductive dust
IIIC Conductive dust

Level of Maximum Surface Temperature

T1 450°c
T2 300°c
T3 200°c
T4 135°c
T5 100°c
T6 85°c

With these ratings and categories in mind and when looking at certain ATEX explosion proof fans, it is easier to understand more about a product range and the ATEX zone type that the fan is certified and suited to.

Interested in the ATEX range?

Inline Ducted ATEX fans

KTEX Rectangular duct fan. ATEX fans

KTEX Rectangular duct ATEX fan

KTEX

II 2G Ex e IIB + H²  T3 Gb

  • (II) Suitable for common surface application
  • (2G) Suitable for zone 1
  • (Ex e) Increased saftey mechanisms
  • (IIB) Suited to applications with Ethylene
  • (H²) Also suitable for applications with Hydrogen
  • (T3) Max surface temperature of 200°c
  • (Gb) Gas equipment protection level
Roof EX fans

DVEX roof ATEX fan. ATEX fans

DVEX roof ATEX fan

DVEX
II 2G c Ex e IIB T3

  • (II) Suitable for common surface application
  • (2G) Suitable for zone 1
  • (Ex e) Increased saftey mechanisms
  • (IIB) Suited to applications with Ethylene
  • (T3) Max surface temperature of 200°c

DVV-EX Roof fan. ATEX fans

DVV-EX Roof ATEX fan

DVV-EX
II 2G c IIB T4

  • (II) Suitable for common surface application
  • (2G) Suitable for zone 1
  • (c) Increased constructional saftey mechanisms
  • (IIB) Suited to applications with Ethylene
  • (T4) Max surface temperature of 135°c
Medium Pressure Axial Fans

 

AXC-EX long cased ATEX axial fan. ATEX fans

AXC-EX long cased ATEX axial fan

AXC-EX
II 2G c Ex d IIC T4 Gb

  • (II) Suitable for common surface application
  • (2G) Suitable for zone 1
  • (c) Increased constructional saftey mechanisms
  • (Ex d) Flameproof
  • (IIC) Suited to applications with Hydrogen and Acetylene
  • (T4) Max surface temperature of 135°c
  • (Gb) Gas equipment protection level

 

AXCBF-EX ATEX certified bifurcated medium pressure axial fan. ATEX fans

AXCBF-EX ATEX certified bifurcated medium pressure axial fan

AXCBF-EX

II 2G c Ex de IIC T4 Gb

  • (II) Suitable for common surface application
  • (2G) Suitable for zone 1
  • (c) Increased constructional saftey mechanisms
  • (Ex de) Flameproof and increased saftey mechanisms
  • (IIC) Suited to applications with Hydrogen and Acetylene
  • (T4) Max surface temperature of 135°c
  • (Gb) Gas equipment protection level

 

Centrifugal Explosion Proof Fans

 

DKEX Radial fan. ATEX fans

DKEX Radial fan

DKEX

II 2G 3G Ex e T1 T2 T3

  • (II) Suitable for common surface application
  • (2G and 3G) Suitable for zone 1 and zone 2
  • (Ex e) Increased saftey mechanisms
  • (T1, T2, T3) Max surface temperature of
    either 450°c, 300°c, 200°c, respectively

 

ATEX centrifugal fan direct drive. ATEX fans

ATEX centrifugal fan direct drive

EX

II 2G 3G Ex de IIA IIB T1 T2 T3 Gb

  • (II) Suitable for common surface application
  • (2G and 3G) Suitable for zone 1 and zone 2
  • (Ex e) Flameproof and Increased saftey mechanisms
  • (IIA and IIB) Suited to applications with propane
    and ethylene
  • (T1, T2, T3) Max surface temperature of either
    450°c, 300°c, 200°c, respectively
Low Pressure Axial EX Fans

AW-EX Axial fan. ATEX fans

AW-EX Axial fan

AW-EX
II 2G c Ex e IIB T4 T3

  • (II) Suitable for common surface application
  • (2G) Suitable for zone 1
  • (c) Increased constructional saftey mechanisms
  • (Ex e) Flameproof and Increased saftey mechanisms
  • (IIB) Suited to applications with ethylene
  • (T4 or T3) Max surface temperature of either
    135°c, or 200°c, respectively
Plastic EX Fans

PRF Plastic radial fan. ATEX fans

PRF Plastic radial fan

PRF-EX

II 2G c Ex e IIB T3

  • (II) Suitable for common surface application
  • (2G) Suitable for zone 1
  • (c) Increased constructional saftey mechanisms
  • (Ex e) Flameproof and Increased saftey mechanisms
  • (IIB) Suited to applications with ethylene
  • (T3) Max surface temperature of 200°c

RVK-EX ATEX circular duct fan. ATEX in explosive environments

RVK-EX ATEX circular duct fan

RVK-EX
II 3G Ex d IIB T4

  • (II) Suitable for common surface application
  • (3G) Suitable for zone 2
  • (Ex d) Flameproof
  • (IIB) Suited to applications with Ethylene
  • (T4) Max surface temperature of 135°c

 

For further information on ATEX clasifications or products on the Puravent range, please visit the Puravent website. Or email further enquiries at info@puravent.co.uk

Destratification Fan Energy Savings

Destratification Fan Energy Savings – The Performance Claims. 

There are many manufacturers of destratification fans these days as people wake up to the

Destratification Fan Energy Savings  - open bladed destratification fan

Conventional open bladed destratification fan

lost energy that lurks beneath their ceilings. But there is a problem – with so many products competing in the market for your custom, the technical and sales information being banded about is becoming fiendishly confusing. Some say that their destratification fan energy savings can as much as 20% of your heating costs, some say 30%, some even say 40 % savings.

So what is the truth of these claims and how do you compare  different models?

 The key advice here is to ignore completely the claims on destratification fan energy savings because they are all true…., in a sense.

Understanding Destratification Fan Energy Savings Potential

Destratification Fan Energy Savings  - Airius Destratification Fans - The most cost effective to operate

Airius destratification fan energy savings are impressive because they are very effective and use very little energy /m2 of floor area.

It is generally accepted that in rooms with stratified air, the temperature differential is typically 2-3°C per 5m hight, and as much as 1°C/m height.  Taking the largest differnetial rate as an example, this means that in a 10m high room the difference between temperature at floor level and ceiling level can be 10°C. The simple truth is that the higher the ceiling the greater the potential temperature differential, and therefore the greater the likely savings from implementing effective thermal destratification fans.

 

How Do Destratification Fans Save Energy

Destratification Fan Energy Savings  -  The helecentrifugal destratification fan

Helecentrifugal destratification fan – Nothing better for greenhouses

The way the savings come through is that when the destratification fans are installed and switched on, air is destratified and the heating system can be set to a lower temperature. Lets assume you have a 10m ceiling and the objective is to heat to 18°C at experienced level.

Assuming 1°C/m as differance (for easy maths), then the air at the air at ceiling level could easily be 28°C. The average of these temperatures is 23°C. In order to achieve the 18°C target, the heating systems needs to work to achieve a 23°C average temperature. The theory is that the cost difference between heating to 18°C, and heating to 23°C is the potential saving that you can achieve, by using destratification fans.

Destratification Fan Energy Savings  - Ssquare destratification fan

Modern square cased destratification fans

Now whether that cost saving is 10, 20, 30 or 40% depends on a whole host of factors, but before discussing that it is worth reflecting that the potential cost saving increases as the ceiling height increases. What this means is that leaving aside the other factors in the potential savings equation, that is very unlikely that 40% heating cost saving will be achieved if your ceiling height is only 3.5m. If on the other hand you have 30m roof line ceiling then 40% heating cost saving is much more likely.

The other factors that determine the extent of the destratification fan energy savings include,

  • Ambient temperature outside
  • Materials of construction and how well insulated the building is
  • The efficiency of the heating system
  • The control accuracy of the heating system
  • The actual temperature differential pre destratification
  • The effectiveness of the destratification fans
  • The running costs of the destratification fans
  • The pricing structure of the running cost to your heating system

Soucing Destratification Fans? – A Little Advice. 

So beware the destratification fan energy savings claims of the manufacturers, but instead endeavor to understand the source and factors influencing the potential savings. The key thing though is  to select destratification fans based on their destratification performance and effectiveness. But before launching into selecting the destratification fan with the highest airflow in the belief that this is the measure of performance, please take a moment to read our guide on destratification fans, because it is not quite as straight forward as that.

 

 

 

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