Source extraction arms

Source extraction arms for effective capture directly at the source

Source extraction arms are among the most important capture elements in industrial air purification. They are used in applications where smoke, dust, vapors, or aerosols are not generated at a fixed machine opening, but rather where the emission source changes during the work process. Thanks to their flexible design, the extraction arms can be positioned directly at the workpiece, weld seam, or machining site and realigned after each work step.

Effectiveness does not depend solely on the fan or the filtration unit. It is crucial that the arm is positioned close enough to the source of the dust, that the required airflow is actually achieved, and that the diameter, length, and design are suitable for the workstation. An arm that is too small or too long can increase pressure loss and reduce capture efficiency. Conversely, a diameter that is too large can result in unnecessarily high air volumes and operating costs.

Which design is suitable for which workplace?

The series differ primarily in terms of their support structure, airflow path, reach, and mechanical load capacity. Compact LGF arms are suitable for small to medium-sized work areas, while RGF and RFF arms cover larger working radii. Steel tube arms are particularly dimensionally stable and robust. Hose arms, on the other hand, offer flexible airflow and are often easier to adapt to changing workplace conditions.

The TGI model features an internal support structure. This keeps the outer surface unobstructed and the arm contour compact. The LE arm with a swiveling hood is designed for larger coverage areas and long reach, such as at extensive welding or machining stations.

Comparison of the Most Important Source Extraction Arms

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Diameter and Air Flow Rate

The connection diameter significantly determines the volume of air that can be transported at an economical flow rate. Small diameters are suitable for compact intake points but result in a correspondingly high pressure loss at high air volumes. Larger diameters reduce the flow rate but require more space and can lead to deposits if the air volume is too low.

Therefore, when designing the system, it is not enough to consider only the arm. The hood, hose, piping, elbows, throttle valves, filters, and fan also influence the available flow rate. The rated power of a fan alone does not indicate the actual amount of air available at the hood.

Reach and Work Area Geometry

An extraction arm should be able to reach all standard working positions without having to be extended to its mechanical limit at all times. At the same time, a range that is significantly greater than necessary usually offers no advantage. As the length increases, so do the arm’s weight, the force required to operate it, and pressure loss. Before making a selection, the work surface, workpiece size, direction of movement, and mounting height should therefore be determined as precisely as possible.

Hose arm or steel tube arm?

Hose arms are versatile and can adapt well to changing workplace conditions. Steel tube arms are dimensionally stable, robust, and provide smooth airflow with minimal wear on the outer sections of the hose. A steel tube arm may be the better choice in cases of mechanical stress, flying sparks, or high durability requirements. For particularly flexible workflows, however, a hose arm is often more practical.

Installation and Connection

Wall brackets, ceiling brackets, or floor stands must safely support the arm’s own weight and the lever forces generated when the arm is fully extended. The connection to the piping system should be made without unnecessary constrictions or tight bends. Flexible connectors can reduce vibrations, but they must not be so long or flexible that they unnecessarily increase pressure loss.

ATEX Source Extraction Arms

In the case of flammable dusts, gases, or vapors, the entire extraction system must be evaluated based on the risk assessment. An ATEX extraction arm alone does not automatically make a system explosion-proof. The fan, filter, ductwork, grounding, electrical components, and potential ignition sources must be compatible with the zone classification and the properties of the substances.

FAQ

How close should the extraction hood be positioned to the source?
As close as practically possible without hindering the workflow. As the distance increases, the capture efficiency decreases significantly, and the required air flow rate increases.

What is a reasonable arm length?
The length should cover all relevant operating positions with some leeway. An unnecessarily long reach increases weight, operating forces, and pressure loss.

Can a source extraction arm be connected to a central filter system?
Yes. This is contingent on the system providing the required flow rate at the respective workstation. If multiple arms are open at the same time, concurrency and air distribution must be taken into account.

What is the difference between RGF and RFF?
RGF models primarily route the air through a flexible hose. RFF models use powder-coated steel pipes and are more mechanically robust.

When is a TGI arm useful?
When an internal support structure and a free-form outer contour are desired. This can be advantageous in tight installation situations or where frequent contact with the arm occurs.

Can an extraction arm be operated without a filtration unit?
The arm itself can be connected to a suitable fan or a central exhaust system. Whether the exhaust air may be filtered or discharged outdoors depends on the contaminant, the process, and operational requirements.

How is the required air flow rate determined?
It depends on the type of pollutant, the hood shape, the distance from the source, and interference flows. For a robust design, pressure losses throughout the entire system should be taken into account.

When is an ATEX-compliant design required?
If an explosive atmosphere could form and the risk assessment requires a corresponding design. The decision always applies to the entire system.