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Rebuild, overhaul & retrofit of industrial fans and impellers

In short: “Because of our engineers and skilled workers, we are able to manufacture our own third-party fans or parts thereof, equivalent to the original. Naaykens’ strength in replacement is not only supplying high-quality fans, but we offer you total technical solutions, tailored to your needs and starting points.”

We are regularly approached with the question of replacing an old fan with a defective impeller or impeller. Often because the company that originally supplied these impellers no longer exists or no longer produces them.

Our engineers have extensive experience in reverse-engineering old impellers; based on drawings, know-how or on measuring an existing impeller.

Of course, we also look at the old design and whether we can make immediate improvements. With a 25-year-old fan, today’s techniques are sometimes much improved, so it is a shame not to apply them immediately.

When rebuilding existing fans, we can provide service in several areas. Consider:

Overhaul of fan or impeller;
Rebuild impeller or impeller based on old drawing;
Rebuild fan based on specifications;
Replaced defective motors and bearings.

1: Old supplied range – PDF

2: Plotted range – 3D CAD

Rebuilding old stainless steel impeller for homogenizing furnace

A customer in the metal industry who has many high-temperature furnaces came to us asking if we could provide them with an impeller for air movement in a high-temperature furnace.

Based on old drawings, we were able to create new models for the same impellers in a short period of time – which we then also produced directly using our skilled suppliers and welders who are experienced with stainless steel.

Technical Characteristics

Reference	Order 83471
Type	Custom, customer specific for oven
Dimensions	Ø1300 mm – blade depth 680 mm
Speed	619 rpm
Material type	Stainless steel version (stainless steel 309)
Finish	Fully welded and glass beaded
Material thicknesses	Front and back plate: 8 mm Blades: >3.2 mm
Specific requirements.	High temperatures, Includes hub that connects to existing drive system

Impression of delivered recreated fans

The photos below show an impression of the impellers produced.
The photos of the rebuilt impellers are before delivery – where the impellers are welded but not yet glass beaded.

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Replacement fan after fire

For another customer, their process unexpectedly did turn out to release large portions of dust; with smoldering pieces also found to be released.

A fire can happen, especially if there is unexpected dust accumulation. Fan overhaul is then often a stopgap measure to get back up and running quickly. But sometimes even that is not possible. Fortunately, after this fire we were able to replace the fan very quickly, after which production could quickly be restarted.

We were also able to apply our expertise to advise the customer on how to prevent both dust accumulation and the unexpected extraction of excessively hot particles in the installation.

Technical Characteristics

Reference	Order 85507
Type	Series 510 Type B135
Flow rate (m3/h)	1.300
Pressure (Pa)	400
Power consumption (kW)	0.18

Impression

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Replacing rusted-out impeller

Exposure to moisture causes an impeller to rust through over time. Apparently, there is a catalyst in the process that causes the rust:

Old age;
Improper preservation of the impeller;
Unexpected wear from airborne particles;
Aggressive gases;
Et cetera.

Therefore, it is very important to replace a rusting impeller in time before it fails. Impeller overhaul is actually almost never an option here. After all, a rusted impeller is unreliable, and it can do a lot of damage if it cracks or breaks during operation.

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Above you can clearly see what a rusted impeller can lead to. The flyaway debris from the rusted through and broken off side has done some good damage. And also the large vibrations from the extreme imbalance also made short work of the rest of the fan. Given that the installation was otherwise working well, we therefore delivered an identical replacement impeller, where the rest of the fan also had to be replaced due to the spontaneous breakage.

Inspecting and intervening in time can prevent large costs. Rust in an impeller is often visible long before it breaks – it is therefore important to install a replacement impeller in good time in the event of such visible defects. In such cases, repairing only a broken impeller is obviously not an option. Timely inspection and intervention before the impeller breaks saves a lot of money, effort and especially headaches. Repairing an impeller during scheduled downtime due to rust or wear before the impeller breaks down is the safest, cheapest and stress-free option.

Naaykens is happy to relieve you completely, with the complete in-house capability for all steps:

Inspection of existing fans;
Advise and be able to perform necessary maintenance;
Balancing impellers so that they vibrate less, making the fan quieter, more efficient, and causing less wear;
Repair of defective parts where possible;
Replacing worn bearings, worn impellers or worn v-belts;
And of course where necessary, replacing worn, rusty and broken parts, impellers or complete fans.

Should this advice have come too late and you have a fan or impeller that has broken, Naaykens is of course happy to help as well:

Emergency repair if possible;
Inspection and advice on which broken parts should be replaced;
Through in-house manufacturing and short lines of communication with suppliers, we can design, manufacture and install an emergency replacement for your fan in a very short time.

In such cases where a solution needs to be found urgently, we advise you to call and send photos. We can then quickly provide you with an estimate of cost and delivery time.

Rush delivery of new range

In a high emergency, we can help you get a replacement impeller like no other. Because of our in-house engineering, inventory and manufacturing including laser cutting, welding and further finishing, we can have a new impeller on site within 24 hours in very close consultation. Note – this of course requires very tight communication and cooperation.

Dangers of rust on fan impeller

Failure to replace an impeller in a timely manner will eventually result in fan failure – with dire consequences. Stalled production, heavy damage to the fan and machinery are then among the possibilities. In cases where only minute amounts of rust or wear are still visible on the impeller then repair is sometimes still an option. However, repairing an impeller is rarely preferred, immensely it will break down faster than a new impeller. A worn impeller will also get unbalanced faster. The cost of a new impeller versus a repair is often not very favorable either. Finally, replacing an impeller has one very big advantage over repairing: the process can continue with the slightly worn or rusted impeller while the replacement impeller is being produced. When repairing an impeller, it is quickly out of service for a few weeks during the repair.

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In this case, the rusty fan impeller had been replaced in time, but the hub had rusted so badly that it had to be cut to remove it. Because the rust was spotted in time, the replacement impeller could be produced and replaced without prolonged production downtime. It could also be inserted into the existing fan without having to replace or overhaul the housing or motor. Without timely inspection, this impeller would have broken down in the fan, and purchasing a complete replacement fan in a hurry is a lot more pricey than replacing the impeller in a timely manner.

New techniques and standards fan construction

The design of the old fan may no longer meet all standards due to changes. Consider:

The ATEX Directives;
Efficiency classes of electric motors (IEC standards).

Especially with fans more than 25 years old, even newer technology can still provide efficiency gains. Consider:

Higher efficiency through improved designs;
A more energy-efficient fan, through smarter design and more precisely laser-cut parts;
Less transmission loss and wear due to direct driven design (frequency controlled) instead of V-belt driven fans.

Other concerns regarding energy consumption and the existing plant may include:

Is the existing fan still working at an optimum efficiency point;
Is the piping properly sized; for example, no right-angle bends exist;
Are valves set properly or is it better to install a frequency regulator.

We would be happy to help you with an energy-efficient and economical replacement for your fan!

Summary

Over time, parts or total fans will need replacement or improvement. Common reasons to consider replacement are wear and tear, capacity problems and energy consumption. Naaykens will assist you with this. Due to our structured archive, we have a good insight into previously delivered fans, but our knowledge also enables us to replace fans or parts of fans from third parties.

When replacing or improving fans, the replacement fan will be made to fit the existing situation, taking into account existing piping and placement. It is also important that the fan meets the current capacity requirements. In the past, the energy consumption of fans has often not been considered as much. It is possible to replace the existing fan with a high efficiency fan produced by our company, which have been developed in recent years.

With the high cost of energy consumption, investments in this area often pay for themselves within six months!

Do you have a fan or impeller that needs replacement? We are happy to take a look and can offer you customized no-obligation advice.