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Advantages of EC medium pressure axial fans

Slingerland Techniek offers efficient EC medium pressure axial fans, which not only impress with their size, but also with their excellent performance. These fans use highly efficient EC technology and have infinitely variable speed control, ensuring maximum airflow. The motor, electronics and aerodynamics are matched for a superior combination.

The advantages of Slingerland Techniek’s EC medium-pressure axial fans are numerous. For example, there is a protective grille on both the suction and discharge side (optional), providing touch protection according to the DIN EN ISO 13857 standard. Moreover, there is plenty of space between the protective grille and the impeller, which ensures a robust design thanks to the steel-coated welded construction.

The impeller

The fan impeller has high efficiency and low vibration thanks to the dynamic balancing in two planes of the impeller-rotor unit. The robust design with blade made of PAG and hub made of corrosion-resistant cast aluminium ensures a long service life.

EC Technology

The electronics of the EC medium-pressure axial fans are also of a high standard. Thus, there is easy commissioning thanks to the central connection section for power supply, fault signal relay, control and communication, which is integrated in the motor. The fan has infinitely variable speed and different voltage variants for worldwide use. Moreover, integrated derating function and integrated blocking and overtemperature protection guarantee reliable operation.

The motor

The fan’s EC motor features precise speed control to ensure fan performance and save energy. The IEC footprint offers interchangeability with induction motors and the market-leading IE5/IE6 efficiency level ensures long service life thanks to maintenance-free ball bearings. By using permanent magnets, there are no magnetic losses in the rotor.

axiaal-ventilator-ec-motor-zonder-background-e1678354734209.png

axiaal-ventilator-ec-motor-achterkant-zonder-background-e1678354758155.png

Design

The motor holder has a robust design thanks to the steel welded construction and the double-flange housing provides lower noise emission and better efficiency with the optional rolled-in suction cone and minimal air gap. The robust sheet steel housing is optionally hot-dip galvanised and stainless steel and is easy to transport and assemble. Various mounting options are available, both with horizontal or vertical motor shaft, both on the suction and discharge side. Optionally, we can also provide cabling so that the connection box is accessible from outside.

Do you have a ventilation problem? Get in touch!

Slingerland Techniek understands that it is difficult for companies to say exactly what they are looking for. To provide the best possible service to companies, we look at the business situation together. We then discuss the possible solutions so that we can solve your business problem in full consultation.

Do you recognise yourself in this problem and would you like to discuss your own situation with our specialists? Then contact us today!

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Understanding fan operation and speed control with variable speed drives

Some basic mechanical laws come into play in the operation of a fan. But what happens when you change the speed by controlling it back with an AC drive? Understanding fan operation and speed control will help you better manage your fan and optimize its performance.

When the fan speed changes, the air volume also changes. This also affects the pressure (∆ PStat) that the fan can handle, which is directly proportional to the air volume. This means that the pressure increases or decreases quadratically with speed.

In addition, the fan’s power input changes to the 3ᵉ power output as the speed changes. This can have important implications for energy consumption and efficiency.

Sample exercises - fan operation and variable frequencies

Here are some exercises that will help you understand fan operation and speed control.

Example 1: Suppose we have a fan with a capacity of 10,000 m³/hour at 60 Hz and a power consumption of 3 kW. We want to increase the capacity to 12,000 m³/hour. What should the new frequency be?

Solution:

(Hz2 / Hz1) x Q1 = Q2

(Hz2 / 60) x 10,000 = 12,000

Hz2 = (12,000 / 10,000) x 60 = 72 Hz

Answer: The new frequency must be 72 Hz.

Example 2: Suppose we have a fan with a pressure of 300 Pa at 50 Hz and a power input of 1 kW. We want to reduce the pressure to 150 Pa. What should the new frequency be?

Solution:

(Hz2 / Hz1) ² x Pa1 = Pa2

(Hz2 / 50) ² x 300 = 150

Hz2 = √[(150 / 300) x 50²] = 35.4 Hz (rounded to 1 decimal place)

Answer: The new frequency should be about 35.4 Hz.

Example 3: Suppose we have a fan with a speed of 1200 opm and a capacity of 8000 m³/hr at 60 Hz. We want to increase the speed to 1500 opm. What should the new frequency be?

Solution:

(Hz2 / Hz1) x n1 = n2

(Hz2 / 60) x 1200 = 1500

Hz2 = (1500 / 1200) x 60 = 75 Hz

Answer: The new frequency must be 75 Hz.

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Convert pressure units of fans and ventilation systems

What is pressure?

Pressure is a fundamental concept in physics that refers to the amount of force per unit area that a substance or object exerts on another surface. Simply put, it is the force applied perpendicularly to the surface of an object divided by the area of that surface. Pressure can be defined as the amount of force distributed over a given surface.

Pressure plays a crucial role in many different areas of science and engineering, including fluid mechanics, thermodynamics and atmospheric science. In these fields, pressure is a crucial parameter that must be carefully controlled and monitored to ensure the effectiveness of systems.

In ventilation systems, pressure is an essential aspect to ensure that the system works effectively. These systems are designed to move air from one place to another, for example in a building or industrial environment. The pressure of the air in the system affects how the air moves, which is crucial to ensure that the system functions as intended.

Pressure in ventilation systems is an essential aspect to ensure the system works effectively. Ventilation systems are designed to move air from one place to another. The pressure of the air in the system affects how the air moves, which is important to ensure that the system works as intended.

In short, pressure is an essential concept that plays a vital role in various scientific and engineering disciplines. Understanding the principles of pressure is crucial to optimising the performance of ventilation systems and ensuring their effectiveness.

Formula

To calculate pressure, we use the formula:

Pressure = Force / Area.

This formula states that pressure is directly proportional to the force applied and inversely proportional to the area over which that force is distributed. Therefore, if the same force is applied to a smaller surface area, it results in a higher pressure.

Conversion factors

The SI unit for pressure is the pascal (Pa), which corresponds to a force of one newton per square metre (N/m²). Other commonly used units for pressure include pounds per square inch (psi), bar and torr.

The relevant units for pressure in ventilation systems are tabulated below.

Abbreviation	Unit
Pa	Pascal
N/m²	newton per square metre
mm H2O	millimeter of water
mbar	millibar
bar	bar
in H2O	inch of water
ft H2O	feet of water

Conversion table

Pressure unit	Pa	N/m²	mm H2O	mbar	bar	in H2O	ft H2O
1 Pa	1	1	0,10197	0,01	0,01	0,0040146	0,003345
1 N/m²	1	1	0,10197	0,01	0,00001	0,0040146	0,0003345
1 mm H2O	9,8067	9,8067	1	0,098067	0,000098067	0,03937	0,0032808
1 mbar	100	100	10,0197	1	0,001	0,40146	0,0033455
1 bar	100.000	100.000	10197	1000	1	401,46	33,455
1 in H2O	249,09	249,09	25,4	2,4909	0,0024909	1	0,08333
1 ft H2O	2989,10	2989,10	304,8	29,981	0,029891	/	1

Not sure of your calculation?

If so, feel free to contact us for no-obligation advice. Our experts will be happy to discuss the options for your requirements with you.

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March 23, 2023

Determining the efficiency of a centrifugal fan.

As you know, there are specific fans available for almost all applications. In this information article, we are going to give you an example of centrifugal fan efficiency. If you want to know more about the operating point or efficiency of your fan, contact us at sales@slingerlandtechniek.nl

Centrifugal fans for drying systems

This week while prospecting, I phoned a potential customer who supplies manure drying systems to poultry farms.

From the customer’s story, it was clear that in autumn and winter, it is very important to dry manure properly because dry manure means less weight, so less cost. They dry this manure using centrifugal fans. These are used to blow in air. After our conversation, the customer was actually immediately interested to get acquainted because the centrifugal fan was an important part of his drying system.

After the pleasant conversation, I sent him an email with a link of our centrifugal fans. The customer then started searching our selection tables himself and sent me the following message not much later;

Email communication

Hi Steven,

Thanks for your email.

Scrolling through the sheets, I don’t actually come across a 7.5KW centrifugal fan that gives 15,000m3h at 2500 pascal pressure.

Do you know which one I should have then?

Response

Hello Sir,

I have briefly studied your application, but we think this is indeed impossible. If anyone else can supply these fans, then I am very curious about the fan curves. Because it seems that these fans generate energy….

To determine the efficiency of a centrifugal fan, we need the following:
Absorbed power is calculated using the following formula:
Air volume x total pressure : 3600 : (efficiency x 10) = power consumption

If we fill this in with the air and pressure data you provide and with the assumption that this fan has 87% efficiency, we arrive at the following formula:

15,000 m3/h x 2500 Pa : 3600 : 870 = 11.97 kW….

So a fan with 87% efficiency has a power consumption of 11.97kW. This means it will never achieve this with a 7.5kW motor.

If we fill in the same formula with 110% efficiency (this is impossible as the machine would generate energy), we arrive at the following data:

15,000 m3/h x 2500 Pa : 3600 : 1100 = 9.46 kW….

So even with this efficiency, the fan does not make it below 7.5kW.

With this explanation, the customer was naturally willing to send the curves of the colleagues.

Conclusion

After studying the curves above, we saw that the numbers were slightly different. From the curve, you can see that the fan can move 12,000 m3/h of air at 1900 pascal pressure.

12,000 m3/h x 1900 Pa :3600 : 870 = 7.2kW

This is already a pretty efficient fan. But we still don’t actually know whether they are talking about dynamic pressure or total pressure. So, very curious, we googled some more and finally found drawings of the fan. This fan has an inlet of 285mm.

If 12,000 m3/h is sucked through this inlet, you have a speed of 55 metres per second and a dynamic pressure loss of 1800 Pa, so there is almost nothing left for the system. So it is very likely that this fan has its operating point somewhere to the left of the curve. So moving less air and building up more pressure.

Since even this data did not really match what the customer wanted, they gave us permission to measure the fan through.

We took measurements and created the actual fan curve, see tables below (the blue dotted line is what the colleagues claim the fan does, and the red line is what we measured).

After these measurements, we were able to show that the fan does not do what the supplier promises, and so we have now supplied alternative ones with 5.5kW motor power. These are going to give the same result.

Measure curves

Contact us for free advice

Slingerland Techniek understands that it is difficult for companies to indicate exactly what they are looking for. To provide companies with the best possible service, we look at the business situation together. The possible solutions are then discussed so that we can solve your business problem in full consultation.

If you have any questions, we are happy to help. You can reach us at +31 (0)33 465 13 92 or by filling in the contact form.

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April 29, 2021

Why you should buy a roof fan

As you know, there are specific fans available for almost all applications. So also in this case: the roof fans. For each application, the space and the objectives must be taken into account. Want to spar with our professionals beforehand? We are at your service via sales@slingerlandtechniek.nl.

To be found in this article:

What does a roof fan do?
What is a roof fan?
How does this roof fan work?
Installation, connection and maintenance of your roof fan

What does a roof fan do?

We can be relatively simple about what a roof fan does. Namely: ventilate. That makes sense. A big advantage of a roof fan is the placement: both on a flat and on a sloping roof, these fans can be placed at your location. Again, the space is essential for the power of the fan. The larger the space, the stronger the fan’s motor must be. Various options are available. Would you like personal advice for your situation? Then you are welcome via sales@slingerlandtechniek.nl.

Why a roof fan?

A roof fan is one of the most diverse ventilation systems on the market. They are mainly used in industry, commercial and residential construction. The fans are equipped with a centrifugal impeller and are distinguished by durability, a sleek and flat design and a fairly low noise level. So you are assured of a pleasant solution in your work environment. Do you want to have a roof fan installed on a sloping roof? Then we have the necessary accessories to make the fan suitable for any roof. Which is very convenient.

How does a roof ventilator work?

A roof fan provides vertically blowing air for optimal ventilation at your business premises. Such as industrial, commercial or residential construction. The fans can be placed on a flat or sloping roof with the right accessories. A horizontal blowing fan is also available: this provides horizontal air displacement and is equipped with an energy-efficient DC motor. Both variants of the roof fan are energy efficient and noise friendly for your environment.

Installation, connection and maintenance

A major advantage of the roof ventilator is that it can be installed by yourself. Would you prefer to outsource to professionals? That is, of course, no problem. If you want to install the fan yourself, we are available for remote assistance. What is important about installing the roof ventilator is that you are not afraid of heights.

Aside from that, installing a roof ventilator is simple. All supplies are included in order to firmly attach the roof fan. Roof fans are suitable against wind attacks and absorb fluctuations in pressure loss. Do you want to install the fan on a sloping roof? Then we recommend ordering the appropriate accessories so that it can be placed perfectly.

Because the roof fans are constantly in the open, it is advisable to check it regularly for proper operation. This applies to both the horizontal and vertical versions. Also, the roof on which the fan is placed does not matter for maintenance. You can do most of the maintenance yourself with a blower or vacuum cleaner with a low capacity. This will prevent the fan from clogging up and will ensure that it works properly. Does the fan start making more noise than before? Then it is time to check what could be stuck. Note: Always wear a helmet and the right equipment when entering the roof, for your safety and of your surroundings.

A different solution applies to every environment. The larger the space, the more powerful the fan’s motor should be. Because roof fans take up little space and can have a high capacity, there are many options available. Both for sloping roofs and for flat roofs. Therefore, always be well informed about which solution is perfectly suited to your situation. Did you know that advice is completely free at Slingerland Techniek? Our professionals are ready to help you at sales@slingerlandtechniek.nl. Also for all your technical questions.