Information

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.

Voorkant axiaal ventilator EC motor

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 motoren

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!

Information

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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Information

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.

Informatie
March 23, 2023

Determining the efficiency of a centrifugal fan.

Centrifugal fans

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.

Het rendement van een centrifugaal ventilator berekenen grafiek

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

Het rendement van een centrifugaal ventilator berekenen grafiek

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.

Case study

Centrifugal fans and coulisse dampers for a drying process

One of our customers, a company specialising in development, construction and maintenance of thermal drying processes received a question from a customer of theirs from the wood industry. Wood chips and sawdust are a source of energy, provided they are sufficiently dried and packaged in a manageable manner. So our client was commissioned to develop a dryer suitable for drying wood chips and fibres sufficiently on a belt dryer. The moisture in the wood chips is reduced so that it can be packed and transported better. This dryer was to be heated using a biofuel-fired furnace.

Input moisture concentration of the material was 55% and output moisture concentration only 12%. The dryer has a capacity of 7500 kg per hour.

Solution through 3 centrifugal fans and coulisse dampeners

Therefore, to carry out this drying process efficiently, sufficient air is needed to dry the material efficiently. It was decided to manufacture the heavy-duty centrifugal fans entirely from steel. Due to the high relative humidity in the medium, the choice was made to apply a high-quality customer-specific coating system suitable for this medium.

In this project, a low noise level was desired for the house radiation and appearance in the press side. To achieve this, centrifugal fans with a low 6-pole speed and adapted material thicknesses were chosen. To reduce the noise level in the press side, coulisse dampers, manufactured entirely from stainless steel 304, were chosen.

Specifications centrifugal fans

Volume: 100,000m3/h |Static pressure: 1420Pa 

  • WEG E motor 75kW/6p/IP65/C5 coating/NU bearings/insulated bearing shield 
  • 2-fold split casing for easy maintenance 
  • inspection doors 
  • condensation drain 2″ 
  • shaft sealing with carbon rings 
  • speed sensor with detection ring 
  • fan made of S355J2/S690QL 
  • class IIV impeller made of stainless steel 304 
  • impeller fitted with counter blades 
  • special coating system for steel parts 
  • cooling impeller with protective cover 
  • fixing materials SS304 
  • impeller balanced according to G2.5 including balance report

Specificaties coulisse dampener

  • dimensions 2200x1750x2500
  • housing and flanges of SS304, fully welded
  • housing for wings made of 304 stainless steel
  • 6 absorption/reflection covers
  • removable wings
  • inner perforated plate of SS304
  • Internal membrane due to high RH
  • coated on the outside for aesthetic reasons
Centrifugaal ventilatoren voor droogproces
Centrifugaal ventilatoren voor droogproces

Also in need of centrifugal fans for drying processes or another solution? Contact us!

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.

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

Case study

Plastic centrifugal fan with stainless steel fan and swing-out option

The customer is a large industrial bakery that produces a wide range of bakery products and needs efficient extraction to ensure the high quality of the final product. At this facility, they make various types of pastry bottoms from yeast doughs and sand doughs. They then offer these both unfilled, semi-filled and fully filled, from unfilled tartelet to ready-made flan.

Fan for extraction of air production lines

The customer was looking for a new solution for the extraction of one of their production lines. In this line, it was important to have sufficient extraction, allowing them to extract unnecessary dust and control the high humidity. This would allow them to improve the quality and shelf life of their finished product.

Solution with plastic centrifugal fan P354

We worked with our client to advise the end user to take a plastic centrifugal fan P354, including a plastic impeller and motor mount equipped with a swing-out option to allow proper cleaning of the fan at the end of the day.

The fan was equipped with a WEG motor of 0.55 kW B5 design. The fan’s PP impeller and PE housing made it corrosion resistant and suitable for use in humid environments. To address the problem of condensate build-up, the fan was equipped with a condensate drainage system that prevented moisture build-up and ensured that the system remained dry even after cleaning.

The fan’s frequency control allowed precise control of fan speed, which not only contributed to energy savings, but also allowed the customer to adjust the airflow to their specific requirements. To ensure the fan’s durability and ease of maintenance, we added additional components, including a motor foundation with a swing-out system made of stainless steel304, a stainless steel304 mesh grille on the discharge side, a flexible connection for the suction side, an ABB operating switch and 4 vibration dampers.

We would love to see what we can do for your business with a plastic centrifugal fan!

Are you struggling with a similar problem in your company? If so, please feel free to contact us for no-obligation advice. We not only have plastic centrifugal fans in our range, but also numerous other fans, and would be happy to discuss the possibilities with you. See you then!

Case study

High Temperature Fans for US furnace industry

Our client is a specialist in the field of industrial furnaces and thermal processes for industry. Their extensive knowledge and experience, together with advanced technologies, enable them to meet specific customer needs and deliver consistently high quality. From standard concepts to customised solutions, small batch ovens to large inline ovens, they offer a wide range of products. Furthermore, depending on the customer, the temperature range of the ovens ranges from 40°C to 1800°C.

High temperature fans for industrial furnace industry

For a recent project in America, 2 industrial furnace fans had to be supplied to withstand high temperatures. Designed specifically for the industrial furnace industry, these high-temperature fans are the ideal choice for efficiency and reliability.

Solution using 2 centrifugal fans

The 2 centrifugal fans have a standard coating in RAL 5017 and are suitable for 22kW 6-pole and 3kW 6-pole motors, respectively. In addition, both fans are equipped with housing insulation and a reduced impeller for 60Hz. This is of great importance as the fans are installed in America. Furthermore, the large fan has a discharge position in LG270 and the small fan in LG0.

Our fans are supplied with 2 Techtop e-motors of 22.0kW and 3kW. The special version is designed for use in industrial applications with a voltage of 3x480V-D-60Hz and has CSA/UL certification and IP55 protection. The motors are made of cast iron and equipped with PTC sensors.

Our client offers a wide range of high temperature fans for the industrial furnace industry. Whether standard or customised, small or large batch furnaces, they have the right solution for your specific needs.

Also in need of high temperature fans for a similar solution? Contact us today!

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.

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

Case study

Stainless steel Centrifugal ventilator for food industry

Our client provides customised solutions for production lines in the potato, fruit and vegetable sector. They integrate and streamline machines in every step of the production process. In this industry, hygiene and quality are very important. High demands are also placed on finishing.

Fan for suction of a strawberry belt

Developing a new machine is not easy and needs to be tailor-made for a process. Our client had a request to develop a machine to automatically remove the crown from strawberries. The strawberries were placed on a belt and had to be sucked with their crown into a small hole. Several strawberries on a belt until it was full and then a knife would automatically run under it and top the strawberries. It was not easy to determine the suction here. But thanks to our engineering department, we were able to go on site and measure what would be needed in terms of suction power. This enabled us to select a suitable fan for our customer.

Solution using stainless steel centrifugal ventilator with pull-out system

In the end, we designed very high-quality stainless steel centrifugal fans with a pull-out system to remove the impellers for easy cleaning. As we use robust impellers, the hinges naturally had to be sufficiently heavy duty. We therefore provided two mounting brackets on the swing-out system and the motor plate was equipped with three quick-release fasteners. We also provided a condensation drain with G½” internal thread. This stainless steel fan was equipped with a 5.5kW 2-pole WEG motor. The fan was manufactured entirely from stainless steel 304, after which it was shot-blasted to give all welds a perfect finish. The fan was fully TIG-welded, which is also very important in the food industry.

Also in need of a stainless steel centrifugal ventilator for a similar solution? Contact us today!

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.

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

Case study

Double-inlet centrifugal fans with backward-curved blades used for spray booth air extraction

A customer of our client wanted to install a new spray booth to be able to finish their products with the latest technology again. Here, of course, it is important to use a suitable ventilation system, such as double-inlet fans. To develop a good ventilation system, several factors need to be considered. One of these factors is the size of the spray booth and the volume that needs to circulate through it. The ventilation system must be able to effectively remove the air pollutants produced, such as paint mists and toxic gases, while ensuring air quality. Because of the toxic gases, the solution also had to comply with Atex guidelines. This is why we chose double-inlet centrifugal fans. Read more about this under the heading “solution”.

Background of the customer

Our client is a company that specialises in providing energy-efficient solutions for commercial and industrial facilities. Their offerings include energy-efficient HVAC systems, lighting systems, building automation systems and renewable energy solutions. Their goal is to help companies reduce their energy consumption and costs, improve indoor air quality and promote sustainability. By offering a wide range of energy-efficient solutions and services, they help their customers create more comfortable and efficient buildings while reducing their impact on the environment.

Solution using double-inlet fans

As a solution, we offered the customer three different double-inlet fans. Namely the VTZ 500, 560 and 710. They comply with T1A ATEX3GZ2. These double-inlet centrifugal fans are specially designed for use in explosive environments and comply with the ATEX guidelines for zone 2 (II 3 G c). The fan housing is welded and coated with 40h RAL5015 for extra protection.

The fans feature a corner frame with block bearings and a discharge flange for easy installation. An inspection hatch is also provided for easy maintenance, as well as a condensation drain to prevent moisture from sticking in the fan housing.

The maximum fan speed is 1820 rpm, 1700 rpm and 1230 rpm, respectively, and the maximum available power is 12, 17 and 22kW. The discharge position is RD/LG90 and grilles are present on both the suction and discharge sides.

Also in need of double-inlet fans for a similar solution? Contact us

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.

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

Case study

Centrifugal fan in stainless steel sound attenuated housing for dust extraction system in the salt industry

One of our customers, Herding filtertechniek, a specialist company of dedusting systems for various industries, received a request from a producer in the salt industry.

In a salt tablet manufacturing process, there was a need for a dedusting system in which our customer could provide a solution by means of a Herding sinter-plate filter and Slingerland Techniek’s centrifugal fan.

Solution using centrifugal fan in sound attenuated housing

Due to the high salt load in the process and the environment, a centrifugal fan and motor with a high-quality coating system were chosen that are suitable for this salt load. The casing was also adapted to this environment by being made of stainless steel 316 panels and aluminium profiles with a suitable coating system.

Operating point & specifications centrifugal fan

Volume: 5000m3/h | Static pressure: 4500Pa

Manufactured from S355J2 steel
High-efficiency impeller with backward-curved blades
Fan casing fully welded
Equipped with special Doublezinc coating system
Fan housing fitted with inspection hatch
Fan housing with condensation drain
Stainless steel fixing materials
WEG E-motor 11kW-2p-IE3
Motor fitted with special coating system
Fan installed vibration-free in casing by means of flexible connection sleeves and vibration dampers

Sound attenuated casing specifications

Dimensions: LxWxH = 1200x1200x1400mm
Stainless steel 316 panels
Stainless steel 316 inspection door with lock and handles
Aluminium profiles with 3-layer powder coating system
Connection suction and discharge side ut RVS316, with collar connection
Akotherm acoustic insulation
Interior suction box with acoustic insulation
Suction and discharge grilles made of 316 stainless steel

Also in need of a centrifugal fan in a sound proofed casing for a similar solution? Contact us today!

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.

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