Conventional screener vs. screening machine with direct excitation

15.05.2025,

Valentina Weber, RHEWUM GmbH

What's the best screening solution for your needs? Given the variety of screening machines available, companies are often faced with the challenge of finding the optimum solution for their specific requirements.

Although all technologies serve the same underlying purpose - separating particles by size - they are fundamentally different in their design, operation and applications. The right choice can not only increase productivity, but also minimize maintenance and downtime, which is crucial in today's competitive industrial landscape. So let's take a look at the differences between conventional motion screens (e.g. gyratory screeners, shaker screeners, etc.) and direct excitation screens to help you decide.

How do oscillating screens work?

Conventional motion screens work with an oscillating movement that is transmitted to the entire screen frame. The movement is generated by eccentric shafts or unbalanced motors and enables the material to move forward on the screen surface and the particles to fall through the meshes.

Benefits:	Drawbacks:
Simple design: These machines have a simple configuration and can be used in a wide range of applications.	Limitations in efficiency: Low vibration amplitudes lead to insufficient acceleration at the screen mesh, which results in mesh blockages and inefficient separation, especially with fine particles.
High throughput rates: Oscillating screens are suitable for applications with large quantities of material and coarse particles.	Higher maintenance costs: Mechanical components such as bearings and drives are subject to high wear. In addition, vibrations are transmitted to the installation and the building, which can cause additional structural damage.
Flexibility: The modular design allows them to be configured for different screen sizes and shapes.	High energy consumption: As the entire screen frame is set in vibration, the energy requirement is comparatively high.

What are screening machines with direct excitation of the screen mesh?

In contrast to conventional oscillating screens, this technology vibrates only the screen mesh directly. This is achieved by special electromagnetic drives, the so-called power packs. The screen frame remains static.

Advantages of direct excitation:

Higher efficiency for fine separation cuts: Direct excitation ensures that even very fine particles can be separated efficiently without clogging the meshes. High-frequency vibrations with accelerations of up to 15 g prevent the meshes from clogging and ensure precise separation performance.
Reduced mechanical stress: The static screen frame minimizes wear on mechanical components, which increases the service life of the machine. The surrounding steel structure and the building are protected.
Ease of maintenance: Screen mesh changes are quick and uncomplicated (= shorter downtime).
Energy saving: Since only the screen mesh is set in motion, energy consumption is lower.

RHEWUM counters the potential disadvantages of this technology with intelligent engineering approaches:

Throughput capacity: With models such as the RHEsono^®, RHEmoto^® or RHEfino^®, RHEWUM offers large-scale screening machines with up to five screening decks that guarantee maximum efficiency even with large quantities of material.
Initial purchase costs: RHEWUM relies on high-quality materials combined with precision manufacturing, which makes the machines durable and low in operating costs. Retrofit and modernization services offer additional flexibility to adapt existing machines to new requirements at reasonable cost.
High sensitivity: A modular design with several small drives ensures high operational reliability (=continuous production). The electronic control of the vibration heads allows the vibration amplitude and frequency to be continuously adjusted during operation, so that the machines can react flexibly to changing material properties.

Bottom line

The choice between a conventional oscillating screen and a screening machine with direct excitation of the screen mesh depends on the application in question. While the simple design and low acquisition costs of conventional motion screens are attractive, machines such as the RHEsono^®, RHEmoto^® or RHEfino^® score points for their efficiency with fine separation cuts, their ease of maintenance and their low energy consumption.

RHEWUM offers a wide range of screening machines optimized for a variety of products with individually matched frequencies and amplitudes. Contact us for a personal consultation and find out which solution best suits your process.